Crayfish neuromuscular facilitation activated by constant presynaptic action potentials and depolarizing pulses

PubMed Central

Zucker, Robert S.

1974-01-01

1. Experiments were conducted to test the hypothesis that facilitation of transmitter release in response to repetitive stimulation of the exciter motor axon to the crayfish claw opener muscle is due to an increase in the amplitude or duration of the action potential in presynaptic terminals. No consistent changes were found in the nerve terminal potential (n.t.p.) recorded extracellularly at synaptic sites on the surface of muscle fibres. 2. Apparent changes in n.t.p. are attributed to three causes. (i) Some recordings are shown to be contaminated by non-specific muscle responses which grow during facilitation. (ii) Some averaged n.t.p.s exhibit opposite changes in amplitude and duration which suggest a change in the synchrony of presynaptic nerve impulses at different frequencies. (iii) Some changes in n.t.p. are blocked by γ-methyl glutamate, an antagonist of the post-synaptic receptor, which suggests that these changes are caused by small muscle movements. 3. The only change in n.t.p. believed to represent an actual change in the intracellular signal is a reduction in n.t.p. amplitude to the second of two stimuli separated by a brief interval. 4. Tetra-ethyl ammonium ions increase synaptic transmission about 20% and prolong the n.t.p. about 15%. This result suggests that an increase in n.t.p. large enough to increase transmission by the several hundred per cent occurring during facilitation would be detected. 5. The nerve terminals are electrically excitable, and most synaptic sites have a diphasic or triphasic n.t.p., which suggests that the motor neurone terminals are actively invaded by nerve impulses. 6. When nerve impulses are blocked in tetrodotoxin, depolarization of nerve terminals increases the frequency of miniature excitatory junctional potentials (e.j.p.s), and a phasic e.j.p. can be evoked by large, brief depolarizing pulses. Responses to repetitive or paired depolarizations of constant amplitude and duration exhibit a facilitation similar to that of e.j.p.s evoked by nerve impulses. 7. It is concluded that facilitation in the crayfish claw opener is not due to a change in the presynaptic action potential, but is due to some change at a later step in the depolarization—secretion process. PMID:4153766

Crayfish neuromuscular facilitation activated by constant presynaptic action potentials and depolarizing pulses.

PubMed

Zucker, R S

1974-08-01

1. Experiments were conducted to test the hypothesis that facilitation of transmitter release in response to repetitive stimulation of the exciter motor axon to the crayfish claw opener muscle is due to an increase in the amplitude or duration of the action potential in presynaptic terminals. No consistent changes were found in the nerve terminal potential (n.t.p.) recorded extracellularly at synaptic sites on the surface of muscle fibres.2. Apparent changes in n.t.p. are attributed to three causes.(i) Some recordings are shown to be contaminated by non-specific muscle responses which grow during facilitation.(ii) Some averaged n.t.p.s exhibit opposite changes in amplitude and duration which suggest a change in the synchrony of presynaptic nerve impulses at different frequencies.(iii) Some changes in n.t.p. are blocked by gamma-methyl glutamate, an antagonist of the post-synaptic receptor, which suggests that these changes are caused by small muscle movements.3. The only change in n.t.p. believed to represent an actual change in the intracellular signal is a reduction in n.t.p. amplitude to the second of two stimuli separated by a brief interval.4. Tetra-ethyl ammonium ions increase synaptic transmission about 20% and prolong the n.t.p. about 15%. This result suggests that an increase in n.t.p. large enough to increase transmission by the several hundred per cent occurring during facilitation would be detected.5. The nerve terminals are electrically excitable, and most synaptic sites have a diphasic or triphasic n.t.p., which suggests that the motor neurone terminals are actively invaded by nerve impulses.6. When nerve impulses are blocked in tetrodotoxin, depolarization of nerve terminals increases the frequency of miniature excitatory junctional potentials (e.j.p.s), and a phasic e.j.p. can be evoked by large, brief depolarizing pulses. Responses to repetitive or paired depolarizations of constant amplitude and duration exhibit a facilitation similar to that of e.j.p.s evoked by nerve impulses.7. It is concluded that facilitation in the crayfish claw opener is not due to a change in the presynaptic action potential, but is due to some change at a later step in the depolarization-secretion process.

The P300 in middle cerebral artery strokes or hemorrhages: Outcome predictions and source localization.

PubMed

Ehlers, Mana R; López Herrero, Carmen; Kastrup, Andreas; Hildebrandt, Helmut

2015-08-01

There are no reliable outcome predictors for severely impaired patients suffering from large infarctions or hemorrhages within the territory of the middle cerebral artery. This study investigated whether the amplitude of the event-related potential (ERP) component P300 predicts if a patient will be transferred to the next stage of rehabilitation (positive outcome) or to a nursing home (negative outcome). The second goal was to look for lesion locations determining the generation of the P300 amplitude. Forty-seven patients performed an auditory oddball task to elicit the P300 and were assessed with different scores for activities of daily living (ADL). Patients were divided in two groups according to their outcome. P300 amplitudes were compared between these groups controlling for age and gender. Post-hoc analyses were performed to analyse the relationship between P300 amplitude and neurological outcome scores. In addition, lesion overlaps were created to detect which lesion pattern affects P300 generation. Patients with a positive outcome showed higher P300 amplitudes at frontal electrode sites than those with a negative outcome. P300 amplitude correlated with ADL score difference. Lesions in the superior temporal gyrus, middle and inferior frontal and prefrontal regions led to visibly diminished P300 amplitudes. The findings suggest that an impairment of attention (P300 amplitude reduction) negatively influences successful neurological rehabilitation. Left superior temporal lobe and the left premotor/prefrontal areas are essential brain areas for the generation of the P300. P300 amplitude may be used as an outcome predictor for severely impaired patients suffering from middle cerebral artery strokes or hemorrhages. Copyright © 2014 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.

Abnormal Selective Attention Normalizes P3 Amplitudes in PDD

ERIC Educational Resources Information Center

Hoeksma, Marco R.; Kemner, Chantal; Kenemans, J. Leon; van Engeland, Herman

2006-01-01

This paper studied whether abnormal P3 amplitudes in PDD are a corollary of abnormalities in ERP components related to selective attention in visual and auditory tasks. Furthermore, this study sought to clarify possible age differences in such abnormalities. Children with PDD showed smaller P3 amplitudes than controls, but no abnormalities in…

[Pattern-reversal electroretinogram (PERG): a normative study in adults].

PubMed

Alves, Letícia Dourado; Berezovsky, Adriana; Sacai, Paula Yuri; Pereira, Josenilson Martins; Salomão, Solange Rios

2010-01-01

To determine normative values for pattern-reversal electroretinogram (PERG) in healthy adult volunteers according to the standard protocol recommended by the International Society for Clinical Electrophysiology of Vision-ISCEV. Participants were 30 healthy volunteers (15 males) with ages from 18 to 61 years (mean= 30.8 +/- 8.7 yrs.; median= 29.5 yrs). Inclusion criteria were: visual acuity of 0.0 logMAR (20/20 Snellen) in each eye, absence of visual complaints, absence of media opacities, negative history for ocular or neurological diseases, negative family history for ocular and informed consent. PERG was recorded from each eye in a darkened room at 1 m from a high resolution display monitor. Stimuli were monochromatic checkerboards subtending 60, 15 e 7.5 minutes of visual angle reversing at 1.9 Hz. Responses were obtained from modified disposable fiber electrodes developed at UNIFESP. Latency (ms) for N35, P50 and N95 components as well as peak-to-peak amplitudes (microV) for N35-P50 and P50-N95 were determined. For normative values only one randomly chosen eye was included. Normal limits were calculated as 97.5% percentiles for latency and 2.5% percentile for amplitudes for each stimulus size. Normal limits for N35, P50 and N95 latencies for 60', 15' and 7.5' stimuli were respectively: N35 - 40.1; 39.9 and 41.3 ms; P50 - 60.5; 64.4 and 65.6 ms and N95 - 103.4; 104.6 and 104.6 ms. For amplitude the normative values for N35-P50 and P50-N95 for 60', 15' and 7.5' were respectively: N35-P50 - 1.7; 1.6 and 0.9 microV; P50-N95 - 3.8; 2.8 and 1.5 microV. No gender differences were found either for latency or for amplitude in the three stimulus sizes. There was no correlation between PERG latency and amplitude with age, except for P50 amplitude for stimulus 15'(r=0.39; P=0.035). Normative values were determined for PERG parameters of amplitude and latency for three stimulus sizes. These parameters are important for evaluating the normal functioning of retinal ganglion cells and the macula. The normative values obtained in this study are comparable to previous studies in the literature.

Effect of flow rate, duty cycle, amplitude, and treatment Time of ultrasonic regimens towards Escherichia coli harbouring lipase

NASA Astrophysics Data System (ADS)

Omar, W. S. A. W.; Sulaiman, A. Z.; Ajit, A.; Chisti, Y.; Chor, A. L. T.

2017-06-01

A full factorial design (FFD) approach was conducted to assess the effect of four factors, namely flow rate, duty cycle, amplitude, and treatment time of ultrasonic regimens towards Escherichia coli harbouring lipase. The 22 experiments were performed as the following values with six replicates of centre point: flow rate (0.1, 0.2, and 0.3 L/min), duty cycle (0, 20, and 40 ), amplitude (2, 6, and 10), and treatment time (10, 35, and 60 min). The FFD was employed as preliminary screening in shake flask cultivation to choose the significant factors (P< 0.05) for further optimisation process. In this study, zero duty cycle signified non-sonication of amplitude and no treatment time effect to the E. coli culture. Also, the designated flow rate and amplitude accordingly showed no effect towards the amount of dry cells weight (DCW). DCW1 was found significantly degraded after the exposure of high duty cycle and treatment time as other factors remained constant. Whereas for the lipase activity, no significant difference was observed in any main factors or interactions. Paired samples t-test confirms the result at a p-value of 0.625. This experimental study suggests the direct and continuous approach of sonication caused an adverse effect on the cells culture density.

Temporal Features of the Differentiation between Self-Name and Religious Leader Name among Christians: An ERP Study

PubMed Central

Xia, Ruixue; Jin, Ruijie; Yong, Lin; Li, Shaodong; Li, Shifeng; Zhou, Aibao

2018-01-01

Existing neuroimaging studies have shown that religion, as a subjective culture, can influence self-referential processing. However, the time course of this impact remains unclear. The present study examined how Christians process their own names, the name of their religious leader (i.e., Jesus), and a famous person’s name (i.e., Yao Ming). Behavioral and EEG data were recorded while the participants performed a name-color judgment task for these three names. The behavioral data showed no significant differences in reaction time or accuracy among the names. However, the ERP data showed that the P200 and P300 amplitudes elicited by the self-name and religious leader name were larger than those elicited by the famous name. Furthermore, the self-name also elicited a larger P300 amplitude than the religious leader name did. These results suggested that both the self-name and the religious leader name were processed preferentially due to their important social value for the self as compared to a generally famous name. Importantly, the dissociation between the self-name and the religious leader name was observed at a high-order cognitive stage, which might be attributed to their different roles in one’s self-concept. PMID:29422874

Purinergic signaling triggers endfoot high-amplitude Ca2+ signals and causes inversion of neurovascular coupling after subarachnoid hemorrhage

PubMed Central

Pappas, Anthony C; Koide, Masayo

2016-01-01

Neurovascular coupling supports brain metabolism by matching focal increases in neuronal activity with local arteriolar dilation. Previously, we demonstrated that an emergence of spontaneous endfoot high-amplitude Ca2+ signals (eHACSs) caused a pathologic shift in neurovascular coupling from vasodilation to vasoconstriction in brain slices obtained from subarachnoid hemorrhage model animals. Extracellular purine nucleotides (e.g., ATP) can trigger astrocyte Ca2+ oscillations and may be elevated following subarachnoid hemorrhage. Here, the role of purinergic signaling in subarachnoid hemorrhage-induced eHACSs and inversion of neurovascular coupling was examined by imaging parenchymal arteriolar diameter and astrocyte Ca2+ signals in rat brain slices using two-photon fluorescent and infrared-differential interference contrast microscopy. We report that broad-spectrum inhibition of purinergic (P2) receptors using suramin blocked eHACSs and restored vasodilatory neurovascular coupling after subarachnoid hemorrhage. Importantly, eHACSs were also abolished using a cocktail of inhibitors targeting Gq-coupled P2Y receptors. Further, activation of P2Y receptors in brain slices from un-operated animals triggered high-amplitude Ca2+ events resembling eHACSs and disrupted neurovascular coupling. Neither tetrodotoxin nor bafilomycin A1 affected eHACSs suggesting that purine nucleotides are not released by ongoing neurotransmission and/or vesicular release after subarachnoid hemorrhage. These results indicate that purinergic signaling via P2Y receptors contributes to subarachnoid hemorrhage-induced eHACSs and inversion of neurovascular coupling. PMID:27207166

Purinergic signaling triggers endfoot high-amplitude Ca2+ signals and causes inversion of neurovascular coupling after subarachnoid hemorrhage.

PubMed

Pappas, Anthony C; Koide, Masayo; Wellman, George C

2016-11-01

Neurovascular coupling supports brain metabolism by matching focal increases in neuronal activity with local arteriolar dilation. Previously, we demonstrated that an emergence of spontaneous endfoot high-amplitude Ca 2+ signals (eHACSs) caused a pathologic shift in neurovascular coupling from vasodilation to vasoconstriction in brain slices obtained from subarachnoid hemorrhage model animals. Extracellular purine nucleotides (e.g., ATP) can trigger astrocyte Ca 2+ oscillations and may be elevated following subarachnoid hemorrhage. Here, the role of purinergic signaling in subarachnoid hemorrhage-induced eHACSs and inversion of neurovascular coupling was examined by imaging parenchymal arteriolar diameter and astrocyte Ca 2+ signals in rat brain slices using two-photon fluorescent and infrared-differential interference contrast microscopy. We report that broad-spectrum inhibition of purinergic (P2) receptors using suramin blocked eHACSs and restored vasodilatory neurovascular coupling after subarachnoid hemorrhage. Importantly, eHACSs were also abolished using a cocktail of inhibitors targeting G q -coupled P2Y receptors. Further, activation of P2Y receptors in brain slices from un-operated animals triggered high-amplitude Ca 2+ events resembling eHACSs and disrupted neurovascular coupling. Neither tetrodotoxin nor bafilomycin A1 affected eHACSs suggesting that purine nucleotides are not released by ongoing neurotransmission and/or vesicular release after subarachnoid hemorrhage. These results indicate that purinergic signaling via P2Y receptors contributes to subarachnoid hemorrhage-induced eHACSs and inversion of neurovascular coupling. © The Author(s) 2016.

Heterosynaptic changes accompany long-term but not short-term potentiation of the perforant path in the anaesthetized rat.

PubMed

Abraham, W C; Bliss, T V; Goddard, G V

1985-06-01

Brief high-frequency trains of electrical stimulation delivered to the perforant path result in long-term potentiation (l.t.p.) of field potentials recorded extracellularly from granule cells of the dentate gyrus. L.t.p. of the population spike is often disproportionately greater than l.t.p. of the population excitatory post-synaptic potential (e.p.s.p.). We have investigated the basis of this effect in rats anaesthetized with sodium pentobarbitone. A series of graded stimuli were given before and after tetanization of the perforant path. From data obtained in this way, we plotted stimulus-response curves, and the relation (E-S curve) between the slope of the population e.p.s.p. (E) and the amplitude of the population spike (S). Curves relating spike onset latency to the slope of the e.p.s.p. were also constructed. Tetanization of the combined medial and lateral components of the perforant path led to long-term changes in the relation between the e.p.s.p. and the population spike. For a given e.p.s.p., the corresponding population spike was of greater amplitude and earlier onset. This E-S potentiation was marked by a shift to the left of the E-S amplitude curve and a downward displacement of the E-S latency curve. Tetanization of the lateral component of the perforant path had two long-term effects on responses evoked by test stimuli to the untetanized medial component: (1) long-term depression of the medial e.p.s.p. and (2) long-term E-S potentiation. The net result of these two heterosynaptically induced effects was to leave unaltered information transfer across medial perforant path-granule cell synapses; for a given test volley the e.p.s.p. was smaller, but because of E-S potentiation the population spike remained relatively unaffected. Short-term potentiation, which has a time course of only a few minutes and is presumed to be mediated by presynaptic mechanisms, was not accompanied by E-S potentiation or by corresponding changes in spike latency. Possible mechanisms of long-term heterosynaptic depression of the e.p.s.p. and of homo- and heterosynaptic E-S potentiation, are discussed. We conclude that although these effects probably reflect a generalized post-synaptic change, this change is unlikely to be a prolonged reduction in the membrane potential of granule cells.

Field-theoretical description of electromagnetic Δ resonance production and determination of the magnetic moment of the Δ+ (1232) resonance by the ep → e' N' π' γ' and γp → N' π' γ' reactions

NASA Astrophysics Data System (ADS)

Machavariani, A. I.; Faessler, Amand; Buchmann, A. J.

1999-02-01

The ep → e' N' π' γ' and γp → N' π' γ' reactions in the Δ resonance region are investigated in the framework of the relativistic field-theoretical spectral decomposition method for the γ ∗N → γ'π'N' transition amplitude. This approach allows us to express the amplitude through three-dimensional diagrams with on-mass shell intermediate states. The Δ resonance is constructed as intermediate cluster state | ΨΔ> with real bare mass MΔ ˜ 1232 MeV and with a complex propagator of Breit-Wigner shape for the P33 π N amplitude. Thus, the usual off-mass shell ambiguities in spin {3}/{2} effective Lagrangians do not affect the present description. Using a unified treatment of nucleons, mesons, and Δ's as bound systems of quarks according to the Haag-Nishijima-Zimmermann field-theoretical approach, it is shown that quark-gluon degrees of freedom only change the rule for constructing the form factors in three-dimensional diagrams for obtaining the γ ∗N → γ'π'N' transition amplitude. However, the structure of these-dimensional diagrams remains the same as in formulations with only meson and nucleon degrees of freedom. A simple redefinition of the γ ∗N → γ'π'N' amplitude which insures gauge invariance in every order of perturbation theory with an arbitrary choice of phenomenological vertices is considered. We calculate the leading diagram of this amplitude in the Δ resonance region. It is demonstrated that the differential cross section of the ep → e' N' π' γ' and γp → N' π' γ' reactions is sensitive to the value of the magnetic moment of the Δ+ resonance. Thus, the measurement of the differential cross section for ep → e' N' π' γ' and γp → N' π' γ' reactions can be used for determining the magnetic dipole moment of Δ+.

How disgust facilitates avoidance: an ERP study on attention modulation by threats.

PubMed

Liu, Yunzhe; Zhang, Dandan; Luo, Yuejia

2015-04-01

This study investigated the attention modulation of disgust in comparison with anger in a dot-probe task. Results indicated a two-stage processing of attention modulation by threats. When participants viewed the cues that were represented by Chinese faces (i.e. the in-group condition), it was found at the early processing stage that an angry face elicited a larger occipital P1 component whereas a disgusted face elicited a smaller P1 for validly than for invalidly cued targets. However, the result pattern was reversed at the later processing stage: the P3 amplitudes were larger for valid disgust cues but were smaller for valid angry cues, when both were compared with invalid cue conditions. In addition, when participants viewed the cues that were represented by foreign faces (i.e. the out-group condition), the attention modulation of disgust/anger diminished at the early stage, whereas enhanced P3 amplitudes were observed in response to validly cued targets in both disgusting and angry conditions at the later stage. The current result implied that although people can perceptually differentiate the emotional categories of out-group faces as accurately as in-group faces, they may still be not able to psychologically understand the subtle differences behind different categories of out-group facial expressions. © The Author (2014). Published by Oxford University Press. For Permissions, please email: journals.permissions@oup.com.

Electroexcitation of the P33(1232), P11(1440), D13(1520), S11(1535) at Q{sup 2} = 0.4 and 0.65(GeV/c){sup 2}

DOE Office of Scientific and Technical Information (OSTI.GOV)

Inna Aznauryan; Volker Burkert; Hovanes Egiyan

2004-07-01

Using two approaches: dispersion relations and isobar model, we have analyzed recent high precision CLAS data on cross sections of {pi}{sup 0}, {pi}{sup +}, and {eta} electroproduction on protons, and the longitudinally polarized electron beam asymmetry for p({rvec e},e{prime}p){pi}{sup 0} and p({rvec e},e{prime}p){pi}{sup +}. The contributions of the resonances P{sub 33}(1232), P{sub 11}(1440), D{sub 13}(1520), S{sub 11}(1535) to {pi} electroproduction and S{sub 11}(1535) to {eta} electroproduction are found. The results obtained in the two approaches are in good agreement with each other. There is also good agreement between amplitudes of the {gamma}* N {yields} S{sub 11}(1535) transition found in {pi}more » and {eta} electroproduction. For the first time accurate results are obtained for the longitudinal amplitudes of the P{sub 11}(1440), D{sub 13}(1520) and S{sub 11}(1535) electroexcitation on protons.« less

Measurement of the polarized structure function σLT' for p(e→,e'p)π0 in the Δ(1232) resonance region

NASA Astrophysics Data System (ADS)

Joo, K.; Smith, L. C.; Burkert, V. D.; Minehart, R.; Adams, G.; Ambrozewicz, P.; Anciant, E.; Anghinolfi, M.; Asavapibhop, B.; Audit, G.; Auger, T.; Avakian, H.; Bagdasaryan, H.; Ball, J. P.; Barrow, S.; Battaglieri, M.; Beard, K.; Bektasoglu, M.; Bellis, M.; Benmouna, N.; Bianchi, N.; Biselli, A. S.; Boiarinov, S.; Bouchigny, S.; Bradford, R.; Branford, D.; Briscoe, W. J.; Brooks, W. K.; Butuceanu, C.; Calarco, J. R.; Carman, D. S.; Carnahan, B.; Cetina, C.; Ciciani, L.; Cole, P. L.; Coleman, A.; Cords, D.; Corvisiero, P.; Crabb, D.; Crannell, H.; Cummings, J. P.; Desanctis, E.; Devita, R.; Degtyarenko, P. V.; Denizli, H.; Dennis, L.; Dharmawardane, K. V.; Dhuga, K. S.; Djalali, C.; Dodge, G. E.; Doughty, D.; Dragovitsch, P.; Dugger, M.; Dytman, S.; Dzyubak, O. P.; Eckhause, M.; Egiyan, H.; Egiyan, K. S.; Elouadrhiri, L.; Empl, A.; Eugenio, P.; Fatemi, R.; Feuerbach, R. J.; Ficenec, J.; Forest, T. A.; Funsten, H.; Gaff, S. J.; Gavalian, G.; Gilad, S.; Gilfoyle, G. P.; Giovanetti, K. L.; Girard, P.; Gordon, C. I.; Griffioen, K.; Guidal, M.; Guillo, M.; Guo, L.; Gyurjyan, V.; Hadjidakis, C.; Hakobyan, R. S.; Hardie, J.; Heddle, D.; Heimberg, P.; Hersman, F. W.; Hicks, K.; Hicks, R. S.; Holtrop, M.; Hu, J.; Hyde-Wright, C. E.; Ilieva, Y.; Ito, M. M.; Jenkins, D.; Kelley, J. H.; Khandaker, M.; Kim, K. Y.; Kim, K.; Kim, W.; Klein, A.; Klein, F. J.; Klimenko, A. V.; Klusman, M.; Kossov, M.; Kramer, L. H.; Kuang, Y.; Kuhn, S. E.; Kuhn, J.; Lachniet, J.; Laget, J. M.; Lawrence, D.; Li, Ji; Lima, A. C.; Lukashin, K.; Manak, J. J.; Marchand, C.; McAleer, S.; McNabb, J. W.; Mecking, B. A.; Mehrabyan, S.; Melone, J. J.; Mestayer, M. D.; Meyer, C. A.; Mikhailov, K.; Mirazita, M.; Miskimen, R.; Morand, L.; Morrow, S. A.; Mozer, M. U.; Muccifora, V.; Mueller, J.; Murphy, L. Y.; Mutchler, G. S.; Napolitano, J.; Nasseripour, R.; Nelson, S. O.; Niccolai, S.; Niculescu, G.; Niculescu, I.; Niczyporuk, B. B.; Niyazov, R. A.; Nozar, M.; O'Rielly, G. V.; Opper, A. K.; Osipenko, M.; Park, K.; Pasyuk, E.; Peterson, G.; Philips, S. A.; Pivnyuk, N.; Pocanic, D.; Pogorelko, O.; Polli, E.; Pozdniakov, S.; Preedom, B. M.; Price, J. W.; Prok, Y.; Protopopescu, D.; Qin, L. M.; Raue, B. A.; Riccardi, G.; Ricco, G.; Ripani, M.; Ritchie, B. G.; Ronchetti, F.; Rossi, P.; Rowntree, D.; Rubin, P. D.; Sabatié, F.; Sabourov, K.; Salgado, C.; Santoro, J. P.; Sapunenko, V.; Sargsyan, M.; Schumacher, R. A.; Serov, V. S.; Sharabian, Y. G.; Shaw, J.; Simionatto, S.; Skabelin, A. V.; Smith, E. S.; Sober, D. I.; Spraker, M.; Stavinsky, A.; Stepanyan, S.; Stoler, P.; Strakovsky, I. I.; Strauch, S.; Taiuti, M.; Taylor, S.; Tedeschi, D. J.; Thoma, U.; Thompson, R.; Todor, L.; Tur, C.; Ungaro, M.; Vineyard, M. F.; Vlassov, A. V.; Wang, K.; Weinstein, L. B.; Weller, H.; Weygand, D. P.; Whisnant, C. S.; Wolin, E.; Wood, M. H.; Yegneswaran, A.; Yun, J.; Zhao, J.; Zhou, Z.

2003-09-01

The polarized longitudinal-transverse structure function σLT' has been measured in the Δ(1232) resonance region at Q2=0.40 and 0.65 GeV2. Data for the p(e→,e'p)π0 reaction were taken at Jefferson Lab with the CEBAF large acceptance spectrometer (CLAS) using longitudinally polarized electrons at an energy of 1.515 GeV. For the first time a complete angular distribution was measured, permitting the separation of different nonresonant amplitudes using a partial wave analysis. Comparison with previous beam asymmetry measurements at MAMI indicate a deviation from the predicted Q2 dependence of σLT' using recent phenomenological models.

Salience of Somatosensory Stimulus Modulating External-to-Internal Orienting Attention.

PubMed

Peng, Jiaxin; Chan, Sam C C; Chau, Bolton K H; Yu, Qiuhua; Chan, Chetwyn C H

2017-01-01

Shifting between one's external and internal environments involves orienting attention. Studies on differentiating subprocesses associated with external-to-internal orienting attention are limited. This study aimed to reveal the characteristics of the disengagement, shifting and reengagement subprocesses by using somatosensory external stimuli and internally generated images. Study participants were to perceive nociceptive external stimuli (External Low (E L ) or External High (E H )) induced by electrical stimulations (50 ms) followed by mentally rehearsing learned subnociceptive images (Internal Low (I L ) and Internal High (I H )). Behavioral responses and EEG signals of the participants were recorded. The three significant components elicited were: fronto-central negativity (FCN; 128-180 ms), fronto-central P2 (200-260 ms), and central P3 (320-380 ms), which reflected the three subprocesses, respectively. Differences in the FCN and P2 amplitudes during the orienting to the subnociceptive images revealed only in the E H but not E L stimulus condition that are new findings. The results indicated that modulations of the disengagement and shifting processes only happened if the external nociceptive stimuli were of high salience and the external-to-internal incongruence was large. The reengaging process reflected from the amplitude of P3 correlated significantly with attenuation of the pain intensity felt from the external nociceptive stimuli. These findings suggested that the subprocesses underlying external-to-internal orienting attention serve different roles. Disengagement subprocess tends to be stimulus dependent, which is bottom-up in nature. Shifting and reengagement tend to be top-down subprocesses, which taps on cognitive control. This subprocess may account for the attenuation effects on perceived pain intensity after orienting attention.

Retest reliability of individual alpha ERD topography assessed by human electroencephalography.

PubMed

Vázquez-Marrufo, Manuel; Galvao-Carmona, Alejandro; Benítez Lugo, María Luisa; Ruíz-Peña, Juan Luis; Borges Guerra, Mónica; Izquierdo Ayuso, Guillermo

2017-01-01

Despite the immense literature related to diverse human electroencephalographic (EEG) parameters, very few studies have focused on the reliability of these measures. Some of the most studied components (i.e., P3 or MMN) have received more attention regarding the stability of their main parameters, such as latency, amplitude or topography. However, spectral modulations have not been as extensively evaluated considering that different analysis methods are available. The main aim of the present study is to assess the reliability of the latency, amplitude and topography of event-related desynchronization (ERD) for the alpha band (10-14 Hz) observed in a cognitive task (visual oddball). Topography reliability was analysed at different levels (for the group, within-subjects individually and between-subjects individually). The latency for alpha ERD showed stable behaviour between two sessions, and the amplitude exhibited an increment (more negative) in the second session. Alpha ERD topography exhibited a high correlation score between sessions at the group level (r = 0.903, p<0.001). The mean value for within-subject correlations was 0.750 (with a range from 0.391 to 0.954). Regarding between-subject topography comparisons, some subjects showed a highly specific topography, whereas other subjects showed topographies that were more similar to those of other subjects. ERD was mainly stable between the two sessions with the exception of amplitude, which exhibited an increment in the second session. Topography exhibits excellent reliability at the group level; however, it exhibits highly heterogeneous behaviour at the individual level. Considering that the P3 was previously evaluated for this group of subjects, a direct comparison of the correlation scores was possible, and it showed that the ERD component is less reliable in individual topography than in the ERP component (P3).

Retest reliability of individual alpha ERD topography assessed by human electroencephalography

PubMed Central

Vázquez-Marrufo, Manuel; Benítez Lugo, María Luisa; Ruíz-Peña, Juan Luis; Borges Guerra, Mónica; Izquierdo Ayuso, Guillermo

2017-01-01

Background Despite the immense literature related to diverse human electroencephalographic (EEG) parameters, very few studies have focused on the reliability of these measures. Some of the most studied components (i.e., P3 or MMN) have received more attention regarding the stability of their main parameters, such as latency, amplitude or topography. However, spectral modulations have not been as extensively evaluated considering that different analysis methods are available. The main aim of the present study is to assess the reliability of the latency, amplitude and topography of event-related desynchronization (ERD) for the alpha band (10–14 Hz) observed in a cognitive task (visual oddball). Topography reliability was analysed at different levels (for the group, within-subjects individually and between-subjects individually). Results The latency for alpha ERD showed stable behaviour between two sessions, and the amplitude exhibited an increment (more negative) in the second session. Alpha ERD topography exhibited a high correlation score between sessions at the group level (r = 0.903, p<0.001). The mean value for within-subject correlations was 0.750 (with a range from 0.391 to 0.954). Regarding between-subject topography comparisons, some subjects showed a highly specific topography, whereas other subjects showed topographies that were more similar to those of other subjects. Conclusion ERD was mainly stable between the two sessions with the exception of amplitude, which exhibited an increment in the second session. Topography exhibits excellent reliability at the group level; however, it exhibits highly heterogeneous behaviour at the individual level. Considering that the P3 was previously evaluated for this group of subjects, a direct comparison of the correlation scores was possible, and it showed that the ERD component is less reliable in individual topography than in the ERP component (P3). PMID:29088307

Sex differences in face gender recognition: an event-related potential study.

PubMed

Sun, Yueting; Gao, Xiaochao; Han, Shihui

2010-04-23

Multiple level neurocognitive processes are involved in face processing in humans. The present study examined whether the early face processing such as structural encoding is modulated by task demands that manipulate attention to perceptual or social features of faces and such an effect, if any, is different between men and women. Event-related brain potentials were recorded from male and female adults while they identified a low-level perceptual feature of faces (i.e., face orientation) and a high-level social feature of faces (i.e., gender). We found that task demands that required the processing of face orientations or face gender resulted in modulations of both the early occipital/temporal negativity (N170) and the late central/parietal positivity (P3). The N170 amplitude was smaller in the gender relative to the orientation identification task whereas the P3 amplitude was larger in the gender identification task relative to the orientation identification task. In addition, these effects were much stronger in women than in men. Our findings suggest that attention to social information in faces such as gender modulates both the early encoding of facial structures and late evaluative process of faces to a greater degree in women than in men.

On the effects of multimodal information integration in multitasking.

PubMed

Stock, Ann-Kathrin; Gohil, Krutika; Huster, René J; Beste, Christian

2017-07-07

There have recently been considerable advances in our understanding of the neuronal mechanisms underlying multitasking, but the role of multimodal integration for this faculty has remained rather unclear. We examined this issue by comparing different modality combinations in a multitasking (stop-change) paradigm. In-depth neurophysiological analyses of event-related potentials (ERPs) were conducted to complement the obtained behavioral data. Specifically, we applied signal decomposition using second order blind identification (SOBI) to the multi-subject ERP data and source localization. We found that both general multimodal information integration and modality-specific aspects (potentially related to task difficulty) modulate behavioral performance and associated neurophysiological correlates. Simultaneous multimodal input generally increased early attentional processing of visual stimuli (i.e. P1 and N1 amplitudes) as well as measures of cognitive effort and conflict (i.e. central P3 amplitudes). Yet, tactile-visual input caused larger impairments in multitasking than audio-visual input. General aspects of multimodal information integration modulated the activity in the premotor cortex (BA 6) as well as different visual association areas concerned with the integration of visual information with input from other modalities (BA 19, BA 21, BA 37). On top of this, differences in the specific combination of modalities also affected performance and measures of conflict/effort originating in prefrontal regions (BA 6).

The effects of self-focus on attentional biases in social anxiety:An ERP study.

PubMed

Judah, Matt R; Grant, DeMond M; Carlisle, Nancy B

2016-06-01

Cognitive theories of social anxiety disorder suggest that biased attention plays a key role in maintaining symptoms. These biases include self-focus and attention to socially threatening stimuli in the environment. The goal of this study was to utilize ERPs that are elicited by a change detection task to examine biases in selective attention (i.e., N2pc) and working memory maintenance (i.e., contralateral delay activity; CDA). Additionally, the effect of self-focus was examined using false heart rate feedback. In support of the manipulation, self-focus cues resulted in greater self-reported self-consciousness and task interference, enhanced anterior P2 amplitude and reduced SPN amplitude. Moreover, P2 amplitude for self-focus cues was correlated with reduced task performance for socially anxious subjects only. The difference in P2 amplitude between self-focus and standard cues was correlated with social anxiety independent of depression. As hypothesized, socially anxious participants (n = 20) showed early selection and maintenance of disgust faces relative to neutral faces as indicated by the N2pc and CDA components. Nonanxious controls (n = 22) did not show these biases. During self-focus cues, controls showed marginal evidence of biased selection for disgust faces, whereas socially anxious subjects showed no bias in this condition. Controls showed an ipsilateral delay activity after being cued to attend to one hemifield. Overall, this study supports early and persistent attentional bias for social threat in socially anxious individuals. Furthermore, self-focus may disrupt these biases. These findings and supplementary data are discussed in light of cognitive models of social anxiety disorder, recent empirical findings, and treatment.

Neurophysiological analyses in different color environments of cognitive function in patients with traumatic brain injury.

PubMed

Kodama, Takayuki; Morita, Kiichiro; Doi, Ryo; Shoji, Yoshihisa; Shigemori, Minoru

2010-09-01

Colors are thought to elicit various emotional effects. Red, with its high likelihood of attracting attention, is considered to have an exciting, active effect; whereas green, with its low attention value, is considered to have a relaxing, sedative effect. Colors are also thought to affect human cognition and emotion. However, there have been few studies of the influence of colors in one's surroundings (e.g., the color environment and its effect on cognitive function). In this study, we investigated the influence of differences in color environments (red, green, or darkness) on cognitive function by analyzing the P300 component of event-related potentials (ERPs) elicited by oddball visual paradigms as a measure of cognitive characteristics in patients who had sustained traumatic brain injury (TBI). In 18 patients with TBI and 18 age-matched control subjects, ERPs were recorded in response to photographs of crying babies. We found that P300 amplitudes in the red environment were significantly larger in controls than in TBI patients, while those in both the green environment and darkness showed no difference between controls and patients. P300 latencies in the red environment and in darkness were significantly longer in patients than in controls. P300 latency in the red environment was significantly shorter than that in darkness. However, P300 latency in the green environment showed no difference between controls and patients. In healthy individuals, the emotional effects of the red environment enhanced cognitive function. In patients with TBI, however, cognitive function was reduced in the red environment. Furthermore, P300 amplitude and latency were strongly correlated with the time on the Trail Making Test (TMT), and the value of the intelligence quotient of the Wechsler Adult Intelligence Scale-III (WAIS-III). These findings suggest that P300 amplitude and latency are useful indexes for the evaluation of TBI patients, and that color environments affect cognitive function.

Theory of electron capture from a hydrogen-like ion by a bare ion with extensions to inner-shell capture

DOE Office of Scientific and Technical Information (OSTI.GOV)

Alston, S.G.

1982-01-01

A complete systematic derivation is given of a new approximation for the calculation of the cross section for electron capture from a hydrogen-like ion of large nuclear charge Z/sub T/e by a bare ion of charge Z/sub p/e moving with speed v. The amplitude in the wave treatment is obtained through consistent expansion in the small parameters Z/sub p//Z/sub T/ and Z/sub p/e/sup 2//hv; however, the ratio Z/sub T/e/sup 2//hv is not assumed small. Electron-target nucleus interactions are included to all orders and electron-projectile interactions were included consistently to first order so that the theory is called the strong potentialmore » Born (SPB). Following a careful analysis of the approach to the energy shell, an off-shell factor is seen to arise which does not appear in the impulse approximation (IA). The effects of this factor on the capture amplitude are explored. It is shown that, in comparison with the IA, the correct weighting of the target spectrum of intermediate states in the SPB significantly alters the 1s ..-->.. ns cross section and at the same time makes peaking approximations to the amplitude more realistic, even for intermediate velocity Z/sub p/e/sup 2//h<« less

Surface electromyographic amplitude does not identify differences in neural drive to synergistic muscles.

PubMed

Martinez-Valdes, Eduardo; Negro, Francesco; Falla, Deborah; De Nunzio, Alessandro Marco; Farina, Dario

2018-04-01

Surface electromyographic (EMG) signal amplitude is typically used to compare the neural drive to muscles. We experimentally investigated this association by studying the motor unit (MU) behavior and action potentials in the vastus medialis (VM) and vastus lateralis (VL) muscles. Eighteen participants performed isometric knee extensions at four target torques [10, 30, 50, and 70% of the maximum torque (MVC)] while high-density EMG signals were recorded from the VM and VL. The absolute EMG amplitude was greater for VM than VL ( P < 0.001), whereas the EMG amplitude normalized with respect to MVC was greater for VL than VM ( P < 0.04). Because differences in EMG amplitude can be due to both differences in the neural drive and in the size of the MU action potentials, we indirectly inferred the neural drives received by the two muscles by estimating the synaptic inputs received by the corresponding motor neuron pools. For this purpose, we analyzed the increase in discharge rate from recruitment to target torque for motor units matched by recruitment threshold in the two muscles. This analysis indicated that the two muscles received similar levels of neural drive. Nonetheless, the size of the MU action potentials was greater for VM than VL ( P < 0.001), and this difference explained most of the differences in EMG amplitude between the two muscles (~63% of explained variance). These results indicate that EMG amplitude, even following normalization, does not reflect the neural drive to synergistic muscles. Moreover, absolute EMG amplitude is mainly explained by the size of MU action potentials. NEW & NOTEWORTHY Electromyographic (EMG) amplitude is widely used to compare indirectly the strength of neural drive received by synergistic muscles. However, there are no studies validating this approach with motor unit data. Here, we compared between-muscles differences in surface EMG amplitude and motor unit behavior. The results clarify the limitations of surface EMG to interpret differences in neural drive between muscles.

Selective depolarization of the muscle membrane in frog nerve-muscle preparations by a chromatographically purified extract of the dinoflagellate Ostreopsis lenticularis

PubMed Central

Meunier, Frédéric A; Mercado, José A; Molgó, Jordi; Tosteson, Thomas R; Escalona de Motta, Gladys

1997-01-01

The actions of a chromatographically identified extract of the marine dinoflagellate Ostreopsis lenticularis, named ostreotoxin-3 (OTX-3), were studied on frog isolated neuromuscular preparations. OTX-3 (1–10 μg ml−1) applied to cutaneous pectoris nerve-muscle preparations depolarized skeletal muscle fibres and caused spontaneous contractions. The depolarization was neither reversed by prolonged washing nor by (+)-tubocurarine. OTX-3 decreased the amplitude of miniature end plate potentials (m.e.p.ps) but did not affect their frequency. Extracellular recording of compound action potentials revealed that OTX-3 affected neither excitability nor conduction along intramuscular nerve branches. End-plate potentials (e.p.ps) elicited by nerve stimulation were reduced in amplitude by OTX-3 and even showed reversed polarity in junctions deeply depolarized by the toxin. Membrane depolarization induced by OTX-3 was decreased about 70% in muscles pretreated for 30 min with 10 μM tetrodotoxin. In contrast, muscles pretreated with 5 μM μ-conotoxin GIIIA were completely insensitive to OTX-3-induced depolarization. OTX-3 did not affect e.p.p. amplitude and the quantal content of e.p.ps in junctions in which muscle depolarization was abolished by μ-conotoxin GIIIA. OTX-3 is a novel type of sodium-channel activating toxin that discriminates between nerve and skeletal muscle membranes. PMID:9249261

Deviance detection by a P3-like response in rat posterior parietal cortex

PubMed Central

Imada, Allicia; Morris, Allyn; Wiest, Michael C.

2013-01-01

To better understand sensory processing in frontal and parietal cortex of the rat, and to further assess the rat as a model of human frontal-parietal processing, we recorded local field potentials (LFPs) from microelectrode arrays implanted in medio-dorsal frontal, and posterior parietal cortex of awake rats as they were presented with a succession of frequent “standard” tones and infrequent “oddball” tones. Extending previous results from surface recordings we found, after controlling for the frequencies of the standard and oddball tones, that rat frontal and parietal-evoked LFPs (eLFPs) exhibit significantly larger N1 (~40 ms latency), P2 (~100 ms), N2 (~160 ms), P3E (~200–240 ms), and P3L (~300–500 ms) amplitudes after an oddball tone. These neural oddball effects could contribute to the automatic allocation of attention to rare stimuli. To determine whether these enhanced responses to rare stimuli could be accounted for in terms of stimulus-specific neural adaptation (SSA), we also recorded during single-tone control sessions involving frequent standard, or infrequent oddball beeps alone. We compared the difference between rare-tone and frequent-tone response amplitudes in the two-tone context (oddball effect) or single-tone context which isolates the contribution of SSA (SSA effect). An analysis of variance (ANOVA) revealed a significant main effect of tone context on rare-tone response enhancements, showing that the rare-tone enhancements were stronger in the two-tone context than the single-tone context. This difference between tone contexts was greatest at the early P3E peak (200–240 ms post-beep) in parietal cortex, suggesting true deviance detection by this evoked response component, which cannot be accounted for in terms of simple models of SSA. PMID:23316147

Increased Amplitude of the P3a ERP Component as a Neurocognitive Marker for Differentiating Amnestic Subtypes of Mild Cognitive Impairment.

PubMed

Correa-Jaraba, Kenia S; Lindín, Mónica; Díaz, Fernando

2018-01-01

The event-related potential (ERP) technique has been shown to be useful for evaluating changes in brain electrical activity associated with different cognitive processes, particularly in Alzheimer's disease (AD). Longitudinal studies have shown that a high proportion of people with amnestic mild cognitive impairment (aMCI) go on to develop AD. aMCI is divided into two subtypes according to the presence of memory impairment only (single-domain aMCI: sdaMCI) or impairment of memory and other cognitive domains (multi-domain aMCI: mdaMCI). The main aim of this study was to examine the effects of sdaMCI and mdaMCI on the P3a ERP component associated with the involuntary orientation of attention toward unattended infrequent novel auditory stimuli. Participants performed an auditory-visual distraction-attention task, in which they were asked to ignore the auditory stimuli (standard, deviant, and novel) and to attend to the visual stimuli (responding to some of them: Go stimuli). P3a was identified in the Novel minus Standard difference waveforms, and reaction times (RTs) and hits (in response to Go stimuli) were also analyzed. Participants were classified into three groups: Control, 20 adults (mean age (M): 65.8 years); sdaMCI, 19 adults (M: 67 years); and mdaMCI, 11 adults (M: 71 years). In all groups, the RTs were significantly longer when Go stimuli were preceded by novel (relative to standard) auditory stimuli, suggesting a distraction effect triggered by novel stimuli; mdaMCI participants made significantly fewer hits than control and sdaMCI participants. P3a comprised two consecutive phases in all groups: early-P3a (e-P3a), which may reflect the orienting response toward the irrelevant stimuli, and late-P3a (l-P3a), which may be a correlate of subsequent evaluation of these stimuli. The e-P3a amplitude was significantly larger in mdaMCI than in sdaMCI participants, and the l-P3a amplitude was significantly larger in mdaMCI than in sdaMCI and Control participants, indicating greater involuntary capture of attention to unattended novel auditory stimuli and allocation of more attentional resources for the subsequent evaluation of these stimuli in mdaMCI participants. The e-P3a and l-P3a components showed moderate to high sensitivity and specificity for distinguishing between groups, suggesting that both may represent optimal neurocognitive markers for differentiating aMCI subtypes.

Increased Amplitude of the P3a ERP Component as a Neurocognitive Marker for Differentiating Amnestic Subtypes of Mild Cognitive Impairment

PubMed Central

Correa-Jaraba, Kenia S.; Lindín, Mónica; Díaz, Fernando

2018-01-01

The event-related potential (ERP) technique has been shown to be useful for evaluating changes in brain electrical activity associated with different cognitive processes, particularly in Alzheimer’s disease (AD). Longitudinal studies have shown that a high proportion of people with amnestic mild cognitive impairment (aMCI) go on to develop AD. aMCI is divided into two subtypes according to the presence of memory impairment only (single-domain aMCI: sdaMCI) or impairment of memory and other cognitive domains (multi-domain aMCI: mdaMCI). The main aim of this study was to examine the effects of sdaMCI and mdaMCI on the P3a ERP component associated with the involuntary orientation of attention toward unattended infrequent novel auditory stimuli. Participants performed an auditory-visual distraction-attention task, in which they were asked to ignore the auditory stimuli (standard, deviant, and novel) and to attend to the visual stimuli (responding to some of them: Go stimuli). P3a was identified in the Novel minus Standard difference waveforms, and reaction times (RTs) and hits (in response to Go stimuli) were also analyzed. Participants were classified into three groups: Control, 20 adults (mean age (M): 65.8 years); sdaMCI, 19 adults (M: 67 years); and mdaMCI, 11 adults (M: 71 years). In all groups, the RTs were significantly longer when Go stimuli were preceded by novel (relative to standard) auditory stimuli, suggesting a distraction effect triggered by novel stimuli; mdaMCI participants made significantly fewer hits than control and sdaMCI participants. P3a comprised two consecutive phases in all groups: early-P3a (e-P3a), which may reflect the orienting response toward the irrelevant stimuli, and late-P3a (l-P3a), which may be a correlate of subsequent evaluation of these stimuli. The e-P3a amplitude was significantly larger in mdaMCI than in sdaMCI participants, and the l-P3a amplitude was significantly larger in mdaMCI than in sdaMCI and Control participants, indicating greater involuntary capture of attention to unattended novel auditory stimuli and allocation of more attentional resources for the subsequent evaluation of these stimuli in mdaMCI participants. The e-P3a and l-P3a components showed moderate to high sensitivity and specificity for distinguishing between groups, suggesting that both may represent optimal neurocognitive markers for differentiating aMCI subtypes. PMID:29483869

Auditory-evoked cortical activity: contribution of brain noise, phase locking, and spectral power

PubMed Central

Harris, Kelly C.; Vaden, Kenneth I.; Dubno, Judy R.

2017-01-01

Background The N1-P2 is an obligatory cortical response that can reflect the representation of spectral and temporal characteristics of an auditory stimulus. Traditionally, mean amplitudes and latencies of the prominent peaks in the averaged response are compared across experimental conditions. Analyses of the peaks in the averaged response only reflect a subset of the data contained within the electroencephalogram (EEG) signal. We used single-trial analyses techniques to identify the contribution of brain noise, neural synchrony, and spectral power to the generation of P2 amplitude and how these variables may change across age group. This information is important for appropriate interpretation of event-related potentials (ERPs) results and in understanding of age-related neural pathologies. Methods EEG was measured from 25 younger and 25 older normal hearing adults. Age-related and individual differences in P2 response amplitudes, and variability in brain noise, phase locking value (PLV), and spectral power (4–8 Hz) were assessed from electrode FCz. Model testing and linear regression were used to determine the extent to which brain noise, PLV, and spectral power uniquely predicted P2 amplitudes and varied by age group. Results Younger adults had significantly larger P2 amplitudes, PLV, and power compared to older adults. Brain noise did not differ between age groups. The results of regression testing revealed that brain noise and PLV, but not spectral power were unique predictors of P2 amplitudes. Model fit was significantly better in younger than in older adults. Conclusions ERP analyses are intended to provide a better understanding of the underlying neural mechanisms that contribute to individual and group differences in behavior. The current results support that age-related declines in neural synchrony contribute to smaller P2 amplitudes in older normal hearing adults. Based on our results, we discuss potential models in which differences in neural synchrony and brain noise can account for associations with P2 amplitudes and behavior and potentially provide a better explanation of the neural mechanisms that underlie declines in auditory processing and training benefits. PMID:25046314

Pattern Differences of Small Hand Muscle Atrophy in Amyotrophic Lateral Sclerosis and Mimic Disorders.

PubMed

Fang, Jia; Liu, Ming-Sheng; Guan, Yu-Zhou; Du, Hua; Li, Ben-Hong; Cui, Bo; Ding, Qing-Yun; Cui, Li-Ying

2016-04-05

Amyotrophic lateral sclerosis (ALS) and some mimic disorders, such as distal-type cervical spondylotic amyotrophy (CSA), Hirayama disease (HD), and spinobulbar muscular atrophy (SBMA) may present with intrinsic hand muscle atrophy. This study aimed to investigate different patterns of small hand muscle involvement in ALS and some mimic disorders. We compared the abductor digiti minimi/abductor pollicis brevis (ADM/APB) compound muscle action potential (CMAP) ratios between 200 ALS patients, 95 patients with distal-type CSA, 88 HD patients, 43 SBMA patients, and 150 normal controls. The ADM/APB CMAP amplitude ratio was significantly higher in the ALS patients (P < 0.001) than that in the normal controls. The ADM/APB CMAP amplitude ratio was significantly reduced in the patients with distal-type CSA (P < 0.001) and the HD patients (P < 0.001) compared with that in the normal controls. The patients with distal-type CSA had significantly lower APB CMAP amplitude than the HD patients (P = 0.004). The ADM/APB CMAP amplitude ratio was significantly lower in the HD patients (P < 0.001) than that in the patients with distal-type CSA. The ADM/APB CMAP amplitude ratio of the SBMA patients was similar to that of the normal controls (P = 0.862). An absent APB CMAP and an abnormally high ADM/APB CMAP amplitude ratio (≥4.5) were observed exclusively in the ALS patients. The different patterns of small hand muscle atrophy between the ALS patients and the patients with mimic disorders presumably reflect distinct pathophysiological mechanisms underlying different disorders, and may aid in distinguishing between ALS and mimic disorders.

Quasi-elastic electroproduction of charged ρ -mesons on nucleons

NASA Astrophysics Data System (ADS)

Sviridova, L. L.; Fedorov, D. K.; Neudatchin, V. G.; Obukhovsky, I. T.; Faessler, A.

2010-06-01

The electroproduction of charged ρ -mesons on the nucleon at intermediate energy is discussed for quasi-elastic kinematics. It is shown that at these kinematics both the longitudinal σ_{{L}}^{} and transverse σ_{{T}}^{} cross-sections are dominated by the ρ -meson t -pole contribution, and thus the corresponding dσ L( T)/d t data can give a valuable information on the ρ -meson component of the nucleon cloud. The differential cross-sections for the reaction p( e, e ' ρ+_{}) n at Q 2 = 2 , 3.5GeV^2 and at the invariant mass W = 3 and 4GeV are calculated on the basis of quasi-elastic knockout mechanism with form factors. Questions about the gauge invariance of the electroproduction amplitude are considered and it is noted an important difference between photo- and electroproduction amplitudes.

Faddeev approach to the reaction K-d →π Σ n at pK=1 GeV /c

NASA Astrophysics Data System (ADS)

Miyagawa, K.; Haidenbauer, J.; Kamada, H.

2018-05-01

The reaction K-d →π Σ n is studied within a Faddeev-type approach, with emphasis on the specific kinematics of the E31 experiment at J-PARC, i.e., K- beam momentum of pK=1 GeV/c and neutron angle of θn=0∘ . The employed Faddeev approach requires as main input amplitudes for the two-body subsystems K ¯N →K ¯N and K ¯N →π Σ . For the latter, results from recently published chiral unitary models of the K ¯N interaction are utilized. The K ¯N →K ¯N amplitude itself, however, is taken from a recent partial-wave analysis. Because of the large incoming momentum of the K-, the K ¯N interaction is probed in a kinematical regime where those chiral potentials are no longer applicable. A comparison of the predicted spectrum for various π Σ charge channels with preliminary data is made and reveals a remarkable agreement as far as the magnitude and the line shape in general is concerned. Noticeable differences observed in the π Σ spectrum around the K ¯N threshold, i.e. in the region of the Λ (1405) resonance, indicate a sensitivity to the details of the employed K ¯N →π Σ amplitudes and suggest that pertinent high-precision data could indeed provide substantial constraints on the structure of the Λ (1405).

Cluster analysis of behavioural and event-related potentials during a contingent negative variation paradigm in remitting-relapsing and benign forms of multiple sclerosis

PubMed Central

2011-01-01

Background Event-related potentials (ERPs) may be used as a highly sensitive way of detecting subtle degrees of cognitive dysfunction. On the other hand, impairment of cognitive skills is increasingly recognised as a hallmark of patients suffering from multiple sclerosis (MS). We sought to determine the psychophysiological pattern of information processing among MS patients with the relapsing-remitting form of the disease and low physical disability considered as two subtypes: 'typical relapsing-remitting' (RRMS) and 'benign MS' (BMS). Furthermore, we subjected our data to a cluster analysis to determine whether MS patients and healthy controls could be differentiated in terms of their psychophysiological profile. Methods We investigated MS patients with RRMS and BMS subtypes using event-related potentials (ERPs) acquired in the context of a Posner visual-spatial cueing paradigm. Specifically, our study aimed to assess ERP brain activity in response preparation (contingent negative variation -CNV) and stimuli processing in MS patients. Latency and amplitude of different ERP components (P1, eN1, N1, P2, N2, P3 and late negativity -LN) as well as behavioural responses (reaction time -RT; correct responses -CRs; and number of errors) were analyzed and then subjected to cluster analysis. Results Both MS groups showed delayed behavioural responses and enhanced latency for long-latency ERP components (P2, N2, P3) as well as relatively preserved ERP amplitude, but BMS patients obtained more important performance deficits (lower CRs and higher RTs) and abnormalities related to the latency (N1, P3) and amplitude of ERPs (eCNV, eN1, LN). However, RRMS patients also demonstrated abnormally high amplitudes related to the preparation performance period of CNV (cCNV) and post-processing phase (LN). Cluster analyses revealed that RRMS patients appear to make up a relatively homogeneous group with moderate deficits mainly related to ERP latencies, whereas BMS patients appear to make up a rather more heterogeneous group with more severe information processing and attentional deficits. Conclusions Our findings are suggestive of a slowing of information processing for MS patients that may be a consequence of demyelination and axonal degeneration, which also seems to occur in MS patients that show little or no progression in the physical severity of the disease over time. PMID:21635741

Negative attention bias and processing deficits during the cognitive reappraisal of unpleasant emotions in HIV+ women.

PubMed

McIntosh, Roger C; Tartar, Jaime L; Widmayer, Susan; Rosselli, Monica

2015-01-01

Deficits in emotional processing may be attributed to HIV disease or comorbid psychiatric disorders. Electrocortical markers of emotional attention, i.e., amplitude of the P2 and late positive potential (LPP), were compared between 26 HIV+ women and 25 healthy controls during an emotional regulation paradigm. HIV+ women showed early attention bias to negative stimuli indexed by greater P2 amplitude. In contrast, compared with the passive viewing of unpleasant images, HIV+ women demonstrated attenuation of the early and late LPP during positive reappraisal. This interaction remained significant after adjusting for individual differences in apathy, anxiety, and depression. Post hoc analyses implicated time since HIV diagnosis with LPP attenuation during positive reappraisal. Advancing HIV disease may disrupt neural generators associated with the cognitive reappraisal of emotions independent of psychiatric function.

Temperature dependence of acoustic harmonics generated by nonlinear ultrasound beam propagation in ex vivo tissue and tissue-mimicking phantoms.

PubMed

Maraghechi, Borna; Kolios, Michael C; Tavakkoli, Jahan

2015-01-01

Hyperthermia is a cancer treatment technique that could be delivered as a stand-alone modality or in conjunction with chemotherapy or radiation therapy. Noninvasive and real-time temperature monitoring of the heated tissue improves the efficacy and safety of the treatment. A temperature-sensitive acoustic parameter is required for ultrasound-based thermometry. In this paper the amplitude and the energy of the acoustic harmonics of the ultrasound backscattered signal are proposed as suitable parameters for noninvasive ultrasound thermometry. A commercial high frequency ultrasound imaging system was used to generate and detect acoustic harmonics in tissue-mimicking gel phantoms and ex vivo bovine muscle tissues. The pressure amplitude and the energy content of the backscattered fundamental frequency (p1 and E1), the second (p2 and E2) and the third (p3 and E3) harmonics were detected in pulse-echo mode. Temperature was increased from 26° to 46 °C uniformly through both samples. The amplitude and the energy content of the harmonics and their ratio were measured and analysed as a function of temperature. The average p1, p2 and p3 increased by 69%, 100% and 283%, respectively as the temperature was elevated from 26° to 46 °C in tissue samples. In the same experiment the average E1, E2 and E3 increased by 163%, 281% and 2257%, respectively. A similar trend was observed in tissue-mimicking gel phantoms. The findings suggest that the harmonics generated due to nonlinear ultrasound beam propagation are highly sensitive to temperature and could potentially be used for noninvasive ultrasound tissue thermometry.

P300 Amplitude in Alzheimer's Disease: A Meta-Analysis and Meta-Regression.

PubMed

Hedges, Dawson; Janis, Rebecca; Mickelson, Stephen; Keith, Cierra; Bennett, David; Brown, Bruce L

2016-01-01

Alzheimer's disease accounts for 60% of all dementia. Numerous biomarkers have been developed that can help in making an early diagnosis. The P300 is an event-related potential that may be abnormal in Alzheimer's disease. Given the possible association between P300 amplitude and Alzheimer's disease and the need for biomarkers in early Alzheimer's disease, the main purpose of this meta-analysis and meta-regression was to characterize P300 amplitude in probable Alzheimer's disease compared to healthy controls. Using online search engines, we identified peer-reviewed articles containing amplitude measures for the P300 in response to a visual or auditory oddball stimulus in subjects with Alzheimer's disease and in a healthy control group and pooled effect sizes for differences in P300 amplitude between Alzheimer's disease and control groups to obtain summary effect sizes. We also used meta-regression to determine whether age, sex, educational attainment, or dementia severity affected the association between P300 amplitude and Alzheimer's disease. Twenty articles containing a total of 646 subjects met inclusion and exclusion criteria. The overall effect size from all electrode locations was 1.079 (95% confidence interval=0.745-1.412, P<.001). The pooled effect sizes for the Cz, Fz, and Pz locations were 1.226 (P<.001), 0.724 (P=.0007), and 1.430 (P<.001), respectively. Meta-regression showed an association between amplitude and educational attainment, but no association between amplitude and age, sex, and dementia severity. In conclusion, P300 amplitude is smaller in subjects with Alzheimer's disease than in healthy controls. © EEG and Clinical Neuroscience Society (ECNS) 2014.

Electrocardiogram of Clinically Healthy Mithun (Bos frontalis): Variation among Strains

PubMed Central

Sanyal, Sagar; Das, Pradip Kumar; Ghosh, Probal Ranjan; Das, Kinsuk; Vupru, Kezha V.; Rajkhowa, Chandan; Mondal, Mohan

2010-01-01

A study was conducted to establish the normal electrocardiogram in four different genetic strains of mithun (Bos frontalis). Electrocardiography, cardiac electrical axis, heart rate, rectal temperature and respiration rate were recorded in a total of 32 adult male mithun of four strains (n = 8 each). It was found that the respiration and heart rates were higher (P < .05) in Manipur than other three strains. Amplitude (P < .05) and duration of P wave and QRS complex differed (P < .01) among the strains. Mizoram strain had the highest amplitude and duration of P wave and QRS complex. On the other hand, higher (P < .05) amplitude and duration of T wave were recorded in Arunachalee and Mizoram strains. The mean electrical axis of QRS complex that were recorded for Arunachalee and Manipur strains were similar to that reported for other bovine species; whereas the electrical axis of QRS for Nagamese and Mizoram strains were more close to feline and caprine species, respectively. In conclusion, electrocardiogram of mithun revealed that the amplitude and duration of P wave, QRS complex and T wave were different among four different genetic strains of mithun and the electrical axis of QRS complex for Nagamese and Mizoram mithuns are dissimilar to bovine species. PMID:20886013

Calibration of Attenuation Structure in Eurasia to Improve Discrimination and Yield

DTIC Science & Technology

2010-09-01

and travel-times over large and tectonically complicated regions. As a result regional discrimination methods (e.g., high-frequency P/S, Ms:mb) and...a poor job of predicting both regional amplitudes and travel-times over large and tectonically complicated regions. As a result regional...regions. Earthquake-explosion discrimination using high-frequency regional P/S amplitude ratios over large and tectonically complicated regions can only

Differences in Sustained Attention Capacity as a Function of Aerobic Fitness.

PubMed

Luque-Casado, Antonio; Perakakis, Pandelis; Hillman, Charles H; Kao, Shih-Chun; Llorens, Francesc; Guerra, Pedro; Sanabria, Daniel

2016-05-01

We investigated the relationship between aerobic fitness and sustained attention capacity by comparing task performance and brain function, by means of event-related potentials (ERP), in high- and low-fit young adults. Two groups of participants (22 higher-fit and 20 lower-fit) completed a 60-min version of the Psychomotor Vigilance Task (PVT). Behavioral (i.e., reaction time) and electrophysiological (ERP) (i.e., contingent negative variation and P3) were obtained and analyzed as a function of time-on-task. A submaximal cardiorespiratory fitness test confirmed the between-groups difference in terms of aerobic fitness. The results revealed shorter reaction time in higher-fit than in lower-fit participants in the first 36 min of the task. This was accompanied by larger contingent negative variation amplitude in the same period of the task in higher-fit than in lower-fit group. Crucially, higher-fit participants maintained larger P3 amplitude throughout the task compared to lower-fit, who showed a reduction in the P3 magnitude over time. Higher fitness was related to neuroelectric activity suggestive of better overall sustained attention demonstrating a better ability to allocate attentional resources over time. Moreover, higher fitness was related to enhanced response preparation in the first part of the task. Taken together, the current data set demonstrated a positive association between aerobic fitness, sustained attention, and response preparation.

Relationships between the resting-state network and the P3: Evidence from a scalp EEG study

NASA Astrophysics Data System (ADS)

Li, Fali; Liu, Tiejun; Wang, Fei; Li, He; Gong, Diankun; Zhang, Rui; Jiang, Yi; Tian, Yin; Guo, Daqing; Yao, Dezhong; Xu, Peng

2015-10-01

The P3 is an important event-related potential that can be used to identify neural activity related to the cognitive processes of the human brain. However, the relationships, especially the functional correlations, between resting-state brain activity and the P3 have not been well established. In this study, we investigated the relationships between P3 properties (i.e., amplitude and latency) and resting-state brain networks. The results indicated that P3 amplitude was significantly correlated with resting-state network topology, and in general, larger P3 amplitudes could be evoked when the resting-state brain network was more efficient. However, no significant relationships were found for the corresponding P3 latency. Additionally, the long-range connections between the prefrontal/frontal and parietal/occipital brain regions, which represent the synchronous activity of these areas, were functionally related to the P3 parameters, especially P3 amplitude. The findings of the current study may help us better understand inter-subject variation in the P3, which may be instructive for clinical diagnosis, cognitive neuroscience studies, and potential subject selection for brain-computer interface applications.

Dysfunction in different phases of working memory in schizophrenia: evidence from ERP recordings.

PubMed

Zhao, Yan Li; Tan, Shu Ping; Yang, Fu De; Wang, Li Li; Feng, Wen Feng; Chan, Raymond C K; Gao, Xiao; Zhou, Dong Feng; Li, Bin Bin; Song, Chong Sheng; Fan, Feng Mei; Tan, Yun Long; Zhang, Jin Guo; Wang, Yun Hui; Zou, Yi Zhuang

2011-12-01

The present study combined a time-locked paradigm and high-time-resolution event-related potential (ERP) recordings to examine different phases of working memory, including early visual processing and late memory-related processes of encoding, maintenance, and retrieval, in 67 adults with schizophrenia and 46 healthy controls. Alterations in ERP components were correlated with task performance. Patients performed significantly worse in the working memory task than healthy subjects, although all subjects' accuracy exceeded 80%. During encoding, the N1 and P2 component amplitudes were lower while the P300 amplitude was higher in schizophrenic patients compared to healthy controls. There were no differences between groups with respect to the mean amplitudes of the negative slow waves in the early stage (the first 400 ms) of the maintenance phase. However, in the next 500-ms time window, the patients exhibited a more negative deflection in the middle fronto-central region than the control group. Likewise, a similar pattern was observed in the second 500-ms period in the middle fronto-central region, although the effect was marginally significant. There were no differences between groups in the remaining 1000 ms. During retrieval, the P1, N1 and P2 amplitudes were lower while the P300 amplitude and latency were higher in schizophrenic patients. The present results indicate early visual deficits in the working memory task in adults with schizophrenia. Impairments in the maintenance phase were confined to the late rehearsal stage. The increased P300 amplitude at the fronto-central electrode sites along with the poorer behavioral performance suggests that schizophrenic patients have an inefficient working memory system. Copyright © 2011 Elsevier B.V. All rights reserved.

Age differences in neural correlates of feedback processing after economic decisions under risk.

PubMed

Fernandes, Carina; Pasion, Rita; Gonçalves, Ana R; Ferreira-Santos, Fernando; Barbosa, Fernando; Martins, Isabel P; Marques-Teixeira, João

2018-05-01

This study examines age-related differences in behavioral responses to risk and in the neurophysiological correlates of feedback processing. Our sample was composed of younger, middle-aged, and older adults, who were asked to decide between 2 risky options, in the gain and loss domains, during an EEG recording. Results evidenced group-related differences in early and later stages of feedback processing, indexed by differences in the feedback-related negativity (FRN) and P3 amplitudes. Specifically, in the loss domain, younger adults showed higher FRN amplitudes after non-losses than after losses, whereas middle-aged and older adults had similar FRN amplitudes after both. In the gain domain, younger and middle-aged adults had higher P3 amplitudes after gains than after non-gains, whereas older adults had similar P3 amplitudes after both. Behaviorally, older adults had higher rates of risky decisions than younger adults in the loss domain, a result that was correlated with poorer performance in memory and executive functions. Our results suggest age-related differences in the outcome-related expectations, as well as in the affective relevance attributed to the outcomes, which may underlie the group differences found in risk-aversion. Copyright © 2018 Elsevier Inc. All rights reserved.

Total Sleep Deprivation and Recovery Sleep Affect the Diurnal Variation of Agility Performance: The Gender Differences.

PubMed

Romdhani, Mohamed; Hammouda, Omar; Smari, Khawla; Chaabouni, Yassine; Mahdouani, Kacem; Driss, Tarak; Souissi, Nizar

2018-05-30

Romdhani, M, Hammouda, O, Smari, K, Chaabouni, Y, Mahdouani, K, Driss, T, and Souissi, N. Total sleep deprivation and recovery sleep affect the diurnal variation of agility performance: The gender differences. J Strength Cond Res XX(X): 000-000, 2018-This study aimed to investigate the effects of time-of-day, 24 and 36 hours of total sleep deprivation (TSD), and recovery sleep (RS) on repeated-agility performances. Twenty-two physical education students (11 male and 11 female students) completed 5 repeated modified agility T-test (RMAT) sessions (i.e., 2 after normal sleep night [NSN] [at 07:00 and 17:00 hours], 2 after TSD [at 07:00 hours, i.e., 24-hour TSD and at 17:00 hours, i.e., 36-hour TSD], and 1 after RS at 17:00 hours). The RMAT index decreased from the morning to the afternoon after NSN (p < 0.05, d = 1.05; p < 0.01, d = 0.73) and after TSD (p < 0.001, d = 0.92; d = 1.08), respectively, for total time (TT) and peak time (PT). This finding indicates a diurnal variation in repeated agility, which persisted after TSD. However, the diurnal increase in PT was less marked in the female group after NSN (2.98 vs. 6.24%). Moreover, TT and PT increased, respectively, after 24-hour TSD (p < 0.001; d = 0.84, d = 0.87) and 36-hour TSD (p < 0.001, d = 1.12; p < 0.01, d = 0.65). Female participants' PT was less affected by 24-hour TSD (1.76 vs. 6.81%) compared with male participants' PT. After 36-hour TSD, the amount of decrease was not different between groups, which increased the diurnal amplitude of PT only for male participants. Total sleep deprivation suppressed the diurnal increase of PT and increased the diurnal amplitude of oral temperature only in women. Nevertheless, RS normalized the sleep-loss-induced performance disruption. Conclusively, sleep loss and RS differently affect repeated-agility performance of men and women during the day. Sleep extension postdeprivation could have potent restorative effect on repeated-agility performances, and female participants could extract greater benefits.

Chevron folding patterns and heteroclinic orbits

NASA Astrophysics Data System (ADS)

Budd, Christopher J.; Chakhchoukh, Amine N.; Dodwell, Timothy J.; Kuske, Rachel

2016-09-01

We present a model of multilayer folding in which layers with bending stiffness EI are separated by a very stiff elastic medium of elasticity k2 and subject to a horizontal load P. By using a dynamical system analysis of the resulting fourth order equation, we show that as the end shortening per unit length E is increased, then if k2 is large there is a smooth transition from small amplitude sinusoidal solutions at moderate values of P to larger amplitude chevron folds, with straight limbs separated by regions of high curvature when P is large. The chevron solutions take the form of near heteroclinic connections in the phase-plane. By means of this analysis, values for P and the slope of the limbs are calculated in terms of E and k2.

Anti-spastic effects of footbaths in post-stroke patients: a proof-of-principle study.

PubMed

Matsumoto, Shuji; Shimodozono, Megumi; Etoh, Seiji; Noma, Tomokazu; Uema, Tomohiro; Ikeda, Keiko; Miyara, Kodai; Tanaka, Nobuyuki; Kawahira, Kazumi

2014-12-01

To investigate whether a footbath inhibits spasticity in the hemiplegic lower limbs of post-stroke patients. Randomized, controlled study. Rehabilitation education and research hospital. Twenty-two post-stroke patients were randomly allocated to control or experimental groups. After relaxing in a supine posture for 30min, the experimental group subject's legs were immersed in 41°C water below the knee joint for 15min, while the control group remained in a resting posture. Modified Ashworth Scale (MAS) scores of the affected triceps surae muscle and F-wave parameters (i.e., F-wave amplitude, F/M ratio, and F-wave persistence) were recorded before, immediately after, and 30min after each intervention. Physiological parameters were simultaneously monitored to determine the thermo-therapeutic mechanisms and side effects of footbath usage. At the time immediately after the intervention, F-wave amplitudes decreased significantly in the experimental group, compared to the control group (p<0.01, difference: -106.8; 95% CI; -181.58 to -32.09). F-wave amplitudes decreased significantly after 30-min intervention in the experimental group, with a total reduction of 161.2μV being recorded compared to 8.8μV increase in the control group (p<0.01, difference: -170.0; 95% CI; -252.73 to -87.33). There were also significant differences between the experimental and control group for both F/M ratio and F-wave persistence, immediately after and 30min after the intervention. Further, there were significant differences between the experimental and control group for the MAS scores immediately after the intervention (p<0.05, difference: -0.72; 95% CI; -1.262 to -0.193), and 30min after the intervention (p<0.05, difference: -0.73; 95% CI; -1.162 to -0.293). These findings demonstrate that the use of footbaths is an effective non-pharmacological anti-spastic treatment for use in stroke rehabilitation. Copyright © 2014 Elsevier Ltd. All rights reserved.

Determining optimal torsional ultrasound power for cataract surgery with automatic longitudinal pulses at maximum vacuum ex vivo.

PubMed

Ronquillo, Cecinio C; Zaugg, Brian; Stagg, Brian; Kirk, Kevin R; Gupta, Isha; Barlow, William R; Pettey, Jeff H; Olson, Randall J

2014-12-01

To determine the optimal longitudinal power settings for Infiniti OZil Intelligent Phaco (IP) at varying torsional amplitude settings; and to test the hypothesis that increasing longitudinal power is more important at lower torsional amplitudes to achieve efficient phacoemulsification. Laboratory investigation. setting: John A. Moran Eye Center, University of Utah, Salt Lake City, Utah. procedure: Individual porcine nuclei were fixed in formalin, then cut into 2.0 mm cubes. Lens cube phacoemulsification was done using OZil IP at 60%, 80%, and 100% torsional amplitude with 0%, 10%, 20%, 30%, 50%, 75%, or 100% longitudinal power. All experiments were done using a 20 gauge 0.9 mm bent reverse bevel phaco tip at constant vacuum (550 mm Hg), aspiration rate (40 mL/min), and bottle height (50 cm). main outcome measure: Complete lens particle phacoemulsification (efficiency). Linear regression analysis showed a significant increase in efficiency with increasing longitudinal power at 60% torsional amplitude (R(2) = 0.7269, P = .01) and 80% torsional amplitude (R(2) = 0.6995, P = .02) but not at 100% amplitude (R(2) = 0.3053, P = .2). Baseline comparison of 60% or 80% vs 100% torsional amplitude without longitudinal power showed increased efficiency at 100% (P = .0004). Increasing longitudinal power to 20% abolished the efficiency difference between 80% vs 100% amplitudes. In contrast, 75% longitudinal power abolished the efficiency difference between 60% vs 100% torsional amplitudes. Results suggest that longitudinal power becomes more critical at increasing phacoemulsification efficiencies at torsional amplitudes less than 100%. Increasing longitudinal power does not further increase efficiency at maximal torsional amplitudes. Copyright © 2014 Elsevier Inc. All rights reserved.

eAMI: A Qualitative Quantification of Periodic Breathing Based on Amplitude of Oscillations

PubMed Central

Fernandez Tellez, Helio; Pattyn, Nathalie; Mairesse, Olivier; Dolenc-Groselj, Leja; Eiken, Ola; Mekjavic, Igor B.; Migeotte, P. F.; Macdonald-Nethercott, Eoin; Meeusen, Romain; Neyt, Xavier

2015-01-01

Study Objectives: Periodic breathing is sleep disordered breathing characterized by instability in the respiratory pattern that exhibits an oscillatory behavior. Periodic breathing is associated with increased mortality, and it is observed in a variety of situations, such as acute hypoxia, chronic heart failure, and damage to respiratory centers. The standard quantification for the diagnosis of sleep related breathing disorders is the apnea-hypopnea index (AHI), which measures the proportion of apneic/hypopneic events during polysomnography. Determining the AHI is labor-intensive and requires the simultaneous recording of airflow and oxygen saturation. In this paper, we propose an automated, simple, and novel methodology for the detection and qualification of periodic breathing: the estimated amplitude modulation index (eAMI). Patients or Participants: Antarctic cohort (3,800 meters): 13 normal individuals. Clinical cohort: 39 different patients suffering from diverse sleep-related pathologies. Measurements and Results: When tested in a population with high levels of periodic breathing (Antarctic cohort), eAMI was closely correlated with AHI (r = 0.95, P < 0.001). When tested in the clinical setting, the proposed method was able to detect portions of the signal in which subclinical periodic breathing was validated by an expert (n = 93; accuracy = 0.85). Average eAMI was also correlated with the loop gain for the combined clinical and Antarctica cohorts (r = 0.58, P < 0.001). Conclusions: In terms of quantification and temporal resolution, the eAMI is able to estimate the strength of periodic breathing and the underlying loop gain at any given time within a record. The impaired prognosis associated with periodic breathing makes its automated detection and early diagnosis of clinical relevance. Citation: Fernandez Tellez H, Pattyn N, Mairesse O, Dolenc-Groselj L, Eiken O, Mekjavic IB, Migeotte PF, Macdonald-Nethercott E, Meeusen R, Neyt X. eAMI: a qualitative quantification of periodic breathing based on amplitude of oscillations. SLEEP 2015;38(3):381–389. PMID:25581914

Entrainment range of the suprachiasmatic nucleus affected by the difference in the neuronal amplitudes between the light-sensitive and light-insensitive regions.

PubMed

Gu, Changgui; Yang, Huijie; Ruan, Zhongyuan

2017-04-01

Mammals not only can be synchronized to the natural 24-h light-dark cycle, but also to a cycle with a non-24-h period. The range of the period of the external cycle, for which the animals can be entrained to, is called the entrainment range, which differs among species. The entrainment range as a characteristic of the animal is determined by the main circadian clock, i.e., the suprachiasmatic nucleus (SCN) in the brain. The SCN is composed of ∼10000 heterogeneous neurons, which can be divided into two subgroups, i.e., the ventrolateral subgroup (VL) directly receiving the light information from the retina and relaying the information to the dorsomedial subgroup (DM). Among the SCN neurons, the amplitudes are different; however, it is unclear that the amplitude is related to the location of the neurons in experiments. In the present study, we examined the effect of the difference in the neuronal amplitude between the VL and the DM on the entrainment range of the SCN, based on a mathematical model, i.e., the Poincaré model, which is used to describe the circadian clock. We find that the maximal entrainment range is obtained when the difference is equal to a critical point. If the difference of the amplitudes of the VL neurons to the amplitudes of the DM neurons is smaller than a critical point, with the increase of the difference, the entrainment range of the SCN increases, while if the difference is larger than the critical point, the entrainment range decreases with the increase of the difference. Our finding may give a potential explanation for the diversity of the entrainment range among species.

Entrainment range of the suprachiasmatic nucleus affected by the difference in the neuronal amplitudes between the light-sensitive and light-insensitive regions

NASA Astrophysics Data System (ADS)

Gu, Changgui; Yang, Huijie; Ruan, Zhongyuan

2017-04-01

Mammals not only can be synchronized to the natural 24-h light-dark cycle, but also to a cycle with a non-24-h period. The range of the period of the external cycle, for which the animals can be entrained to, is called the entrainment range, which differs among species. The entrainment range as a characteristic of the animal is determined by the main circadian clock, i.e., the suprachiasmatic nucleus (SCN) in the brain. The SCN is composed of ˜10 000 heterogeneous neurons, which can be divided into two subgroups, i.e., the ventrolateral subgroup (VL) directly receiving the light information from the retina and relaying the information to the dorsomedial subgroup (DM). Among the SCN neurons, the amplitudes are different; however, it is unclear that the amplitude is related to the location of the neurons in experiments. In the present study, we examined the effect of the difference in the neuronal amplitude between the VL and the DM on the entrainment range of the SCN, based on a mathematical model, i.e., the Poincaré model, which is used to describe the circadian clock. We find that the maximal entrainment range is obtained when the difference is equal to a critical point. If the difference of the amplitudes of the VL neurons to the amplitudes of the DM neurons is smaller than a critical point, with the increase of the difference, the entrainment range of the SCN increases, while if the difference is larger than the critical point, the entrainment range decreases with the increase of the difference. Our finding may give a potential explanation for the diversity of the entrainment range among species.

Influence of education level on design-induced N170 and P300 components of event related potentials in the human brain.

PubMed

Begum, Tahamina; Reza, Faruque; Ahmed, Izmer; Abdullah, Jafri Malin

2014-03-01

Simple geometric and organic shapes and their arrangement are being used in different neuropsychology tests for the assessment of cognitive function, special memory and also for the therapy purpose in different patient groups. Until now there is no electrophysiological evidence of cognitive function determination for simple geometric, organic shapes and their arrangement. Then the main objective of this study is to know the cortical processing and amplitude, latency of visual induced N170 and P300 event related potential components on different geometric, organic shapes and their arrangement and different educational influence on it, which is worthwhile to know for the early and better treatment for those patient groups. While education influenced on cognitive function by using auditory oddball task, little is known about the influence of education on cognitive function induced by visual attention task in case of the choice of geometric, organic shapes and their arrangements. Using a 128-electrode sensor net, we studied the responses of the choice of the different geometric and organic shapes randomly in experiment 1 and their arrangements in experiment 2 in the high, medium and low education groups. In both experiments, subjects push the button "1" or "2" if like or dislike, respectively. Total 45 healthy subjects (15 in each group) were recruited. ERPs were measured from 11 electrode sites and analyzed to see the evoked N170/N240 and P300 ERP components. There were no differences between like and dislike in amplitudes even in latencies in every stimulus in both experiments. We fixed geometric shapes and organic shapes stimuli only, not like and dislike. Upon the stimulus types, N170 ERP component was found instead of N240, in occipito-temporal (T5, T6, O1 and O2) locations where the amplitude is the highest at O2 location and P300 was distributed in the central (Cz and Pz) locations in both experiments in all groups. In experiment 1, significant low amplitude and non-significant larger latency of the N170 component are found out at O1 location for both stimuli in low education group comparing medium education groups, but in experiment 2, there is no significant difference between stimuli among groups in amplitude and latency. In both experiments, P300 component was found in Cz and Pz locations though the amplitudes are higher at Cz than Pz areas. In experiment 1, medium education group evoked significantly (geometric shape stimuli, P = 0.05; organic shape stimuli, P = 0.02) higher amplitude of P300 component comparing low education group at Cz location. Whereas, there is no significant difference of amplitudes among groups across stimuli in Cz and Pz locations in experiment 2. Latencies have no significant differences in both experiments among groups also, but longer latency are found in low education group at Cz location comparing medium education group, though not significant. We conclude that simple geometric shapes, organic shapes and their arrangements evoked visual N170 component at temporo-occipital areas with right lateralization and P300 ERP component at centro-parietal areas. Significant low amplitude of N170 and P300 ERP components and longer latencies during different shape stimuli in low education group prove that, low education significantly influence on visual cognitive functions in low education group.

Sex dimorphism in a mediatory role of the posterior midcingulate cortex in the association between anxiety and pain sensitivity.

PubMed

Kisler, Lee-Bareket; Granovsky, Yelena; Sinai, Alon; Sprecher, Elliot; Shamay-Tsoory, Simone; Weissman-Fogel, Irit

2016-11-01

Behavioral studies found greater pain sensitivity in females that vanishes fully or partially when controlling for the emotional state. Furthermore, pain-related brain activation hints at the role of limbic structures in sex differences in pain processing. We aimed to investigate the role of pain-related limbic structures in mediating the relation between subjects' affective state (i.e., anxiety) and pain. Contact heat-evoked potentials (CHEPs) were recorded in 26 healthy subjects (13 males) simultaneously with innocuous (42 °C) baseline and target noxious (52 °C) series of stimuli administered to the left non-dominant volar forearm. The N2 and P2 components were analyzed, and their generators' activity was estimated using standardized low-resolution brain electromagnetic tomography. Thereafter, structural equation modeling (SEM) was applied separately for females and males, examining the mediatory role of the CHEPs' limbic structures generators [posterior midcingulate cortex (pMCC), insula, amygdala, and hippocampus] in the anxiety-pain sensitivity association. Females exhibited greater P2 amplitudes that were highly associated with larger pMCC activity (r = 0.910, p < 0.001). This correlation was also evident in males, though with less strength (r = 0.578, p = 0.039). Moreover, the P2 amplitudes were associated both in females (r = 0.645, p = 0.017) and males (r = 0.608, p = 0.028) with the activity of the amygdala\\hippocampus\\insula. SEM revealed that the relationship between state anxiety and pain ratings was only in females fully mediated via the effect of the pMCC on the P2 amplitude. These findings suggest that sexual dimorphism in anxiety-related brain activity may explain the differences found in CHEPs and the sex-related association between anxiety and pain.

Early exposure to general anesthesia with isoflurane downregulates inhibitory synaptic neurotransmission in the rat thalamus

PubMed Central

Joksovic, Pavle M.; Lunardi, Nadia; Jevtovic-Todorovic, Vesna; Todorovic, Slobodan M.

2015-01-01

Recent evidence supports the idea that common general anesthetics (GAs) such as isoflurane (Iso) and nitrous oxide (N2O; laughing gas) are neurotoxic and may harm the developing mammalian brain, including the thalamus; however, to date very little is known about how developmental exposure to GAs may affect synaptic transmission in the thalamus which, in turn, controls the function of thalamocortical circuitry. To address this issue we used in vitro patch-clamp recordings of evoked inhibitory postsynaptic currents (eIPSCs) from intact neurons of the nucleus reticularis thalami (nRT) in brain slices from rat pups (postnatal age P10-P18) exposed at age of P7 to clinically relevant GA combinations of Iso and N2O. We found that rats exposed to a combination of 0.75% Iso and 75% N2O display lasting reduction in the amplitude and faster decays of eIPSCs. Exposure to sub-anesthetic concentrations of 75% N2O alone or 0.75% Iso alone at P7 did not affect the amplitude of eIPSCs; however, Iso alone, but not N2O, significantly accelerated decay of eIPSCs. Anesthesia with 1.5% Iso alone decreased amplitudes, caused faster decay and decreased the paired-pulse ratio of eIPSCs. We conclude that anesthesia at P7 with Iso alone or in combination with N2O causes plasticity of eIPSCs in nRT neurons by both presynaptic and postsynaptic mechanisms. We hypothesize that changes in inhibitory synaptic transmission in the thalamus induced by GAs may contribute to altered neuronal excitability and consequently abnormal thalamocortical oscillations later in life. PMID:26048671

Sex and the money--How gender stereotypes modulate economic decision-making: An ERP study.

PubMed

Fabre, Eve F; Causse, Mickael; Pesciarelli, Francesca; Cacciari, Cristina

2015-08-01

In the present event-related potential study, we investigated whether and how participants playing the ultimatum game as responders modulate their decisions according to the proposers' stereotypical identity. The proposers' identity was manipulated using occupational role nouns stereotypically marked with gender (e.g., Teacher; Engineer), paired with either feminine or masculine proper names (e.g., Anna; David). Greater FRN amplitudes reflected the early processing of the conflict between the strategic rule (i.e., earning as much money as possible) and ready-to-go responses (i.e., refusing unequal offers and discriminating proposers according to their stereotype). Responders were found to rely on a dual-process system (i.e., automatic and heuristic-based system 1 vs. cognitively costly and deliberative system 2), the P300 amplitude reflecting the switch from a decision making system to another. Greater P300 amplitudes were found in response to both fair and unfair offers and male-stereotyped proposers' offers reflecting an automatic decision making based on heuristics, while lower P300 amplitudes were found in response to 3€ offers and the female-stereotyped proposers' offers reflecting a more deliberative reasoning. Overall, the results indicate that participants were more motivated to engage in a costly deliberative reasoning associated with an increase in acceptation rate when playing with female-stereotyped proposers, who may have induced more positive and emphatic feelings in the participants than did male-stereotyped proposers. Then, we assume that people with an occupation stereotypically marked with female gender and engaged in an economic negotiation may benefit from their occupation at least in the case their counterparts lose their money if the negotiation fails. Copyright © 2015 Elsevier Ltd. All rights reserved.

Y2-receptor-mediated selective inhibition of slow, inhibitory postsynaptic potential in submucous neurones of guinea-pig caecum.

PubMed Central

Cunningham, S M; Mihara, S; Lees, G M

1994-01-01

1. The subtype of neuropeptide Y receptor mediating the selective inhibition of the slow inhibitory postsynaptic potential (i.p.s.p.) of submucous neurones in guinea-pig caecum was investigated by use of conventional intracellular electrophysiological recording techniques. 2. Neuropeptide Y (NPY) (1-300 nM) was found to depress or abolish reversibly the slow i.p.s.p. evoked by focal stimulation of internodal fibre tracts. At low concentrations (1-30 nM), a reduction in the duration of the slow i.p.s.p. was often apparent before any inhibition of the amplitude of this synaptic potential. 3. These inhibitory effects of NPY were mimicked by peptide YY (PYY; 0.3-100 nM), NPY13-36 (1-300 nM) and NPY22-36 (10-100 nM); [Leu31,Pro34]NPY ([Pro34]NPY) and bovine pancreatic polypeptide (bPP) were without pre- or postsynaptic effects at concentrations of up to 300 nM. The IC50 +/- s.e. mean values for PYY, NPY, and NPY13-36 were 2.7 +/- 0.3, 7.8 +/- 2.1 and 30 +/- 4.8 nM, respectively, and were significantly different from each other. Thus, the apparent rank order of potency was PYY > NPY > NPY13-36 >> [Pro34]NPY and bPP. 4. In concentrations of up to 300 nM, NPY and its analogues had no depressant effects on the active and passive properties of the impaled neurone and did not affect the amplitude or duration of either cholinergic fast synaptic potentials or non-cholinergic, slow excitatory postsynaptic potentials (e.p.s.ps). Furthermore, none of these peptides altered the amplitude or time-course of changes in membrane potential induced by focal application of acetylcholine or noradrenaline.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:7858881

The Association Between P3 Amplitude at Age 11 and Criminal Offending at Age 23

PubMed Central

Gao, Yu; Raine, Adrian; Venables, Peter H.; Mednick, Sarnoff A.

2014-01-01

Reduced P3 amplitude to targets is an information-processing deficit associated with adult antisocial behavior and may reflect dysfunction of the temporal-parietal junction. This study aims to examine whether this deficit precedes criminal offending. From a birth cohort of 1,795 children, 73 individuals who become criminal offenders at age 23 and 123 noncriminal individuals were assessed on P3 amplitude. The two groups did not differ on gender, ethnicity, and social adversity. P3 amplitude was measured over the temporal-parietal junction during a visual continuous performance task at age 11, together with antisocial behavior. Criminal convictions were assessed at age 23. Reduced P3 amplitude at age 11 was associated with increased antisocial behavior at age 11. Criminal offenders showed significantly reduced P3 amplitudes to target stimuli compared to controls. Findings remained significant after controlling for antisocial behavior and hyperactivity at age 11 and alcoholism at age 23. P3 deficits at age 11 are associated with adult crime at age 23, suggesting that reduced P3 may be an early neurobiological marker for cognitive and affective processes subserved by the temporal-parietal junction that place a child at risk for adult crime. PMID:22963083

The association between p3 amplitude at age 11 and criminal offending at age 23.

PubMed

Gao, Yu; Raine, Adrian; Venables, Peter H; Mednick, Sarnoff A

2013-01-01

Reduced P3 amplitude to targets is an information-processing deficit associated with adult antisocial behavior and may reflect dysfunction of the temporal-parietal junction. This study aims to examine whether this deficit precedes criminal offending. From a birth cohort of 1,795 children, 73 individuals who become criminal offenders at age 23 and 123 noncriminal individuals were assessed on P3 amplitude. The two groups did not differ on gender, ethnicity, and social adversity. P3 amplitude was measured over the temporal-parietal junction during a visual continuous performance task at age 11, together with antisocial behavior. Criminal convictions were assessed at age 23. Reduced P3 amplitude at age 11 was associated with increased antisocial behavior at age 11. Criminal offenders showed significantly reduced P3 amplitudes to target stimuli compared to controls. Findings remained significant after controlling for antisocial behavior and hyperactivity at age 11 and alcoholism at age 23. P3 deficits at age 11 are associated with adult crime at age 23, suggesting that reduced P3 may be an early neurobiological marker for cognitive and affective processes subserved by the temporal-parietal junction that place a child at risk for adult crime.

Prediction of Auditory and Visual P300 Brain-Computer Interface Aptitude

PubMed Central

Halder, Sebastian; Hammer, Eva Maria; Kleih, Sonja Claudia; Bogdan, Martin; Rosenstiel, Wolfgang; Birbaumer, Niels; Kübler, Andrea

2013-01-01

Objective Brain-computer interfaces (BCIs) provide a non-muscular communication channel for patients with late-stage motoneuron disease (e.g., amyotrophic lateral sclerosis (ALS)) or otherwise motor impaired people and are also used for motor rehabilitation in chronic stroke. Differences in the ability to use a BCI vary from person to person and from session to session. A reliable predictor of aptitude would allow for the selection of suitable BCI paradigms. For this reason, we investigated whether P300 BCI aptitude could be predicted from a short experiment with a standard auditory oddball. Methods Forty healthy participants performed an electroencephalography (EEG) based visual and auditory P300-BCI spelling task in a single session. In addition, prior to each session an auditory oddball was presented. Features extracted from the auditory oddball were analyzed with respect to predictive power for BCI aptitude. Results Correlation between auditory oddball response and P300 BCI accuracy revealed a strong relationship between accuracy and N2 amplitude and the amplitude of a late ERP component between 400 and 600 ms. Interestingly, the P3 amplitude of the auditory oddball response was not correlated with accuracy. Conclusions Event-related potentials recorded during a standard auditory oddball session moderately predict aptitude in an audiory and highly in a visual P300 BCI. The predictor will allow for faster paradigm selection. Significance Our method will reduce strain on patients because unsuccessful training may be avoided, provided the results can be generalized to the patient population. PMID:23457444

Observation of the Forbidden Magnetic Dipole Transition 6{sup 2}P{sub ?} --> 7{sup 2}P{sub ?} in Atomic Thallium

DOE R&D Accomplishments Database

Chu, S.

1976-10-01

A measurement of the 6{sup 2}P{sub ?} --> 7{sup 2}P{sub ?} forbidden magnetic dipole matrix element in atomic thallium is described. A pulsed, linearly polarized dye laser tuned to the transition frequency is used to excite the thallium vapor from the 6{sup 2}P{sub ?} ground state to the 7{sup 2}P{sub ?} excited state. Interference between the magnetic dipole M1 amplitude and a static electric field induced E1 amplitude results in an atomic polarization of the 7{sup 2}P{sub ?} state, and the subsequent circular polarization of 535 nm fluorescence. The circular polarization is seen to be proportional to / as expected, and measured for several transitions between hyperfine levels of the 6{sup 2}P{sub ?} and 7{sup 2}P{sub ?} states. The result is = -(2.11 +- 0.30) x 10{sup -5} parallel bar e parallel bar dirac constant/2mc, in agreement with theory.

Different proactive and reactive action control in fencers' and boxers' brain.

PubMed

Bianco, Valentina; Di Russo, Francesco; Perri, Rinaldo Livio; Berchicci, Marika

2017-02-20

Practicing sport at top level requires excellent physical and cognitive skills. The goal of the present study was to investigate whether specific sport practice may affect the preparation-perception-action stages of processing during a visuo-motor task requiring perceptual discrimination and fast response. We recruited 39 participants (two groups of professional fencers and boxers, and a control group; N=13 for each group) and measured behavioral performance and event-related potentials (ERPs) while performing a go/no-go task. Results revealed that athletes were faster than controls, while fencers were more accurate than boxers. ERP analysis revealed that motor preparation, indexed by the Bereitschaftspotential (BP), was increased in athletes than controls, whereas the top-down attentional control, reflected by the prefrontal negativity (pN) component, was enhanced only in fencers when compared to controls. Most of the post-stimulus ERPs i.e. the N1, the N2, the P3, and the pP2, were enhanced in fencers. Combat sports require fast action execution, but the preparatory brain activity might differ according to the specific practice required by each discipline. Boxers might afford to commit more errors (as reflected by high commission error (CE) rate and by a small pN amplitude), while fencers have to be as much fast and accurate as possible (thanks to an enhanced pN amplitude). Although the possible influence of repetitive head blows on cerebral activity cannot be excluded in boxers, our results suggest that cognitive benefits of high-level sport practice might also be transferred to the daily (i.e., no sport-related) activities. Copyright © 2016 IBRO. Published by Elsevier Ltd. All rights reserved.

A general population twin study of conduct problems and the auditory P300 waveform.

PubMed

Bertoletti, Eleonora; Michelini, Giorgia; Moruzzi, Sara; Ferrer, Giuseppina; Ferini-Strambi, Luigi; Stazi, Maria Antonietta; Ogliari, Anna; Battaglia, Marco

2014-01-01

Reduced amplitude of the P300 event-related potential has been consistently associated with a variety of externalising problems, including conduct disorder. The few available genetically-informative studies of these relationships, however, were conducted among adolescents/adults (i.e., at an age when conduct disorder has typically already become manifest). Among 200 general population twins with a mean age of 9 years (range 6-14 years), we studied the relationship between the P300 waveform elicited by an auditory oddball task and the DSM-oriented conduct problems scale of the Child Behavior Checklist 6-18. Conduct problems scores were negatively and significantly correlated (r = -0.19, p = 0.01) with P300 amplitude; correlations between P300 amplitude and the other DSM-oriented Child Behavior Checklist scales were non-significant, except for oppositional defiant problems (p = 0.01). We found moderate heritability estimates for both P300 amplitude (0.58, CI:0.37;0.73) and conduct problems (0.52, CI:0.25;0.70). Bivariate twin analyses indicated that the covariation between these two phenotypes can be explained by additive genetic factors only, with a genetic correlation of -0.33. An association between reduced P300 amplitude and conduct problems can be substantiated already in childhood, at an age that precedes the most typical onset of conduct disorder. This relationship appears to be genetic in nature. Reduced P300 amplitude can represent a valuable marker for conduct problems, and can contribute to the early identification of children at high-risk for conduct disorder.

The interaction between hexamethonium and tubocurarine on the rat neuromuscular junction.

PubMed Central

Rang, H. P.; Rylett, R. J.

1984-01-01

The ability of hexamethonium (C6) to reverse the neuromuscular blocking action of tubocurarine (Tc) has been reinvestigated at the voltage clamped endplate of the omohyoid muscle of rat. The possibility that a weak anticholinesterase action of C6 could contribute to the paradoxical potentiation of the peak amplitude of the endplate response has been examined. C6 (50-200 microM) caused an increase in the amplitude of nerve-evoked endplate currents (e.p.cs) recorded in the presence of 0.6 microM Tc. The effect decreased with hyperpolarization of the muscle fibre. Irreversible inhibition of acetylcholinesterase resulted in a loss of the anti-curare effect of C6. C6 did not cause an increase in e.p.c. amplitude when acetylcholine (ACh) receptors were blocked irreversibly by alpha-bungaratoxin. When transmission was blocked by increased Mg2+ concentration, C6 (50-400 microM) reduced the amplitude of e.p.cs without appreciably affecting their time course. C6 caused a decrease in the amplitude of miniature endplate currents (m.e.p.cs) the effect being slightly increased when the fibre was hyperpolarized. An e-fold increase in the effectiveness of C6 occurred with approximately 58 mV hyperpolarization. High concentrations (greater than 400 microM) affected the time course of m.e.p.cs in a manner suggestive of open channel block, but this was not evident at 200 microM, the concentration that was most effective in reversing Tc block. When tested against responses to short ionophoretic pulses of agonists, C6 was less effective against ACh (EC50ca. 300 microM) than against carbachol (CCh) (EC50 100 microM). When cholinesterase was irreversibly inhibited, C6 blocked responses to both agonists equally (EC50ca. 100 microM). The effectiveness of C6 in blocking the action of CCh was reduced 10 fold in the presence of 0.6 microM Tc, implying that the two antagonists compete for the same binding site. C6 (50-200 microM) in the presence of Tc (0.6 microM) increased the response to ionophoretically applied ACh but not that to CCh. C6 was equipotent in blocking m.e.p.cs and responses to ionophoretically applied ACh whereas Tc was more potent against the exogenously applied agonist. C6 was a weak inhibitor of acetylcholinesterase activity in rat muscle homogenates (EC50 1.5 mM). The results are discussed in terms of the kinetic hypothesis advanced by Ginsborg & Stephenson (1974) to account for the Tc reversal phenomenon.(ABSTRACT TRUNCATED AT 400 WORDS) PMID:6141831

Gender differences in the recognition of spatially transformed figures: behavioral data and event-related potentials (ERPs).

PubMed

Mikhailova, E S; Slavutskaya, A V; Gerasimenko, N Yu

2012-08-30

The gender differences in accuracy, reaction time (RT) and amplitude of the early P1 and N1 components of ERPs during recognition of previously memorized objects after their spatial transformation were examined. We used three levels of the spatial transformation: a displacement of object details in radial direction, and a displacement in combination with rotation of the details by ±0° to 45° and ±45° to 90°. The accuracy and the RT data showed a similarity of task performance in males and females. The effect of rotation was significantly greater than the effect of simple displacement, and the accuracy decreased, and the RT increased with the rotation angle in both genders. At the same time we found significant sex differences in the early stage of visual processing. In males the P1 peak amplitude at the P3/P4 sites increased significantly during the recognition of spatially transformed objects, and the wider the angle of rotation the greater the P1 peak amplitude. In contrast, in females the P1 peak amplitude did not depend on the rotation of figure details. The N1 amplitude revealed no gender differences, although the object transformation evoked somewhat greater changes in the N1 at the O1/O2 sites in females compared to males. This new fact that only males demonstrated the sensitivity of early perceptual stage to the transformation of objects adds information about the neurobiological basis of different strategies in the visual processing used by each gender. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

Clarifying Relations Between Dispositional Aggression and Brain Potential Response: Overlapping and Distinct Contributions of Impulsivity and Stress Reactivity

PubMed Central

Venables, Noah C.; Patrick, Christopher J.; Hall, Jason R.; Bernat, Edward M.

2011-01-01

Impulsive-aggressive individuals exhibit deficits in amplitude of the P3 brain potential response, however, it remains unclear how separable dispositional traits account for this association. The current study sought to clarify the basis of this association by examining contributions of trait impulsiveness and stress reactivity to the observed relationship between dispositional aggression and amplitude of the P3 brain potential response in a visual novelty-oddball procedure. A significant negative association was found between aggressiveness and amplitude of P3 response to both target and novel stimuli over frontal-central scalp sites. Impulsivity showed a parallel inverse relationship with P3 amplitude, attributable to its overlap with dispositional aggression. In contrast, stress reactivity did not exhibit a zero-order association with P3 amplitude, but modestly predicted P3 in a positive direction after accounting for its overlap with aggression. Results are discussed in terms of their implications for individual difference variables and brain processes underlying impulsive-aggressive behavior. PMID:21262318

The electrophysiological correlate of saliency: evidence from a figure-detection task.

PubMed

Straube, Sirko; Fahle, Manfred

2010-01-11

Although figure-ground segregation in a natural environment usually relies on multiple cues, we experience a coherent figure without usually noticing the individual single cues. It is still unclear how various cues interact to achieve this unified percept and whether this interaction depends on task demands. Studies investigating the effect of cue combination on the human EEG are still lacking. In the present study, we combined psychophysics, ERP and time-frequency analysis to investigate the interaction of orientation and spatial frequency as visual cues in a figure detection task. The figure was embedded in a matrix of Gabor elements, and we systematically varied figure saliency by changing the underlying cue configuration. We found a strong correlation between the posterior P2 amplitude and the perceived saliency of the figure: the P2 amplitude decreased with increasing saliency. Analogously, the power of the theta-band decreased for more salient figures. At longer latencies, the posterior P3 component was modulated in amplitude and latency, possibly reflecting increased decision confidence at higher saliencies. In conclusion, when the cue composition (e.g. one or two cues) or cue strength is changed in a figure detection task, first differences in the electrophysiological response reflect the perceived saliency and not directly the underlying cue configuration.

High test-retest-reliability of pain-related evoked potentials (PREP) in healthy subjects.

PubMed

Özgül, Özüm Simal; Maier, Christoph; Enax-Krumova, Elena K; Vollert, Jan; Fischer, Marc; Tegenthoff, Martin; Höffken, Oliver

2017-04-24

Pain-related evoked potentials (PREP) is an established electrophysiological method to evaluate the signal transmission of electrically stimulated A-delta fibres. Although prerequisite for its clinical use, test-retest-reliability and side-to-side differences of bilateral stimulation in healthy subjects have not been examined yet. We performed PREP twice within 3-14days in 33 healthy subjects bilaterally by stimulating the dorsal hand. Detection (DT) and pain thresholds (PT) after electrical stimulation, the corresponding pain ratings, latencies of P0, N1, P1 and N2 components and the corresponding amplitudes were assessed. Impact of electrically induced pain intensity, age, sex, and arm length on PREP was analysed. MANOVA, t-Test, interclass correlation coefficient (ICC), standard error of measurement (SEM), smallest real difference (SRD), Bland-Altmann-Analysis as well as ANCOVA were used for statistical analysis. Measurement from both sides on both days resulted in mean N1-latencies from 142.39±18.12ms to 144.03±16.62ms and in mean N1P1-amplitudes from 39.04±12.26μV to 40.53±12.9μV. Analysis of a side-to-side effect showed for the N1-latency a F-value of 0.038 and for the N1P1-amplitude of 0.004 (p>0.8). We found intraclass correlation coefficients (ICC) from 0.88 to 0.93 and a standard error of measurement (SEM)<10% of mean values for all measurements concerning the N1-Latency and N1P1-amplitude. Intraclass correlation coefficients, standard error of measurement and Bland-Altman-Analyses revealed excellent test-retest-reliability for N1-latency and N1P1-amplitude without systematic error and there was no side-to-side effect on PREP. N1-latency (r=0.35, p<0.05) and N1P1-amplitude (r=-0.45, p<0.05) correlated with age and additionally N1-latency correlated with arm length (r=0.45, p<0.001). In contrast, pain intensity during the stimulation had no effect on both N1-latency and N1P1-amplitude. In summary, PREP showed high test-retest-reliability and negligible side-to-side differences concerning the commonly used parameters N1-latency and N1P1-amplitude. Copyright © 2017 Elsevier B.V. All rights reserved.

Suppression of cognitive function in hyperthermia; From the viewpoint of executive and inhibitive cognitive processing

NASA Astrophysics Data System (ADS)

Shibasaki, Manabu; Namba, Mari; Oshiro, Misaki; Kakigi, Ryusuke; Nakata, Hiroki

2017-03-01

Climate change has had a widespread impact on humans and natural systems. Heat stroke is a life-threatening condition in severe environments. The execution or inhibition of decision making is critical for survival in a hot environment. We hypothesized that, even with mild heat stress, not only executive processing, but also inhibitory processing may be impaired, and investigated the effectiveness of body cooling approaches on these processes using the Go/No-go task with electroencephalographic event-related potentials. Passive heat stress increased esophageal temperature (Tes) by 1.30 ± 0.24 °C and decreased cerebral perfusion and thermal comfort. Mild heat stress reduced the amplitudes of the Go-P300 component (i.e. execution) and No-go-P300 component (i.e. inhibition). Cerebral perfusion and thermal comfort recovered following face/head cooling, however, the amplitudes of the Go-P300 and No-go-P300 components remained reduced. During whole-body cooling, the amplitude of the Go-P300 component returned to the pre-heat baseline, whereas that of the No-go-P300 component remained reduced. These results suggest that local cooling of the face and head does not restore impaired cognitive processing during mild heat stress, and response inhibition remains impaired despite the return to normothermia.

Electroexcitation of the P{sub 33}(1232), P{sub 11}(1440), D{sub 13}(1520), and S{sub 11}(1535) at Q{sup 2}=0.4 and 0.65 (GeV/c){sup 2}

DOE Office of Scientific and Technical Information (OSTI.GOV)

Aznauryan, I.G.; Burkert, V.D.; Egiyan, H.

2005-01-01

Using two approaches - dispersion relations and the isobar model - we have analyzed recent high precision CLAS data on cross sections of {pi}{sup 0}, {pi}{sup +}, and {eta} electroproduction on protons, and the longitudinally polarized electron beam asymmetry for p(e{sup {yields}},e{sup '}p){pi}{sup 0} and p(e{sup {yields}},e{sup '}n){pi}{sup +}. The contributions of the resonances P{sub 33}(1232), P{sub 11}(1440), D{sub 13}(1520), and S{sub 11}(1535) to {pi} electroproduction and of S{sub 11}(1535) to {eta} electroproduction are found. The results obtained using the two approaches are in good agreement. There is also good agreement between amplitudes of the {gamma}*N{yields}S{sub 11}(1535) transition found inmore » {pi} and {eta} electroproduction. For the first time accurate results are obtained for the longitudinal amplitudes of the P{sub 11}(1440), D{sub 13}(1520), and S{sub 11}(1535) electroexcitations on protons. A strong longitudinal response is found for the Roper resonance, which rules out presentation of this resonance as a hybrid state.« less

Intensity dependence narrowing of electromagnetically induced absorption in a Doppler-broadened medium

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dimitrijevic, J.; Arsenovic, D.; Jelenkovic, B. M.

In this paper, we present a theoretical model for studying the interaction between linearly polarized laser light and near-degenerated Zeeman sublevels for a multiple V-type atomic system of {sup 2}S{sub 1/2}F{sub g}=2{yields}{sup 2}P{sub 3/2}F{sub e}=3 transition in {sup 87}Rb. We have calculated the laser absorption in a Hanle configuration, as well as the amplitudes and the widths of electromagnetically induced absorption (EIA) in the range of laser intensities from 0.01 to 40 mW/cm{sup 2}. Our results, showing nonvanishing EIA amplitude, a nonmonotonic increase of the EIA width for the increase of laser intensity, and pronounced shape differences of the Hanlemore » EIA curves at different laser intensities, are in good agreement with recent experimental results. We have found that the EIA behaves differently than the electromagnetically induced transparency (EIT) as a function of the laser intensity. Both the amplitude and width of the EIA have narrow maximums at 1 to 2 mW/cm{sup 2}. We have shown the strong influence of Doppler broadening of atomic transition on Hanle resonances and have suggested the explanation of it.« less

Accessing the real part of the forward elastic J/Psi-p and Phi-p threshold scattering amplitudes

NASA Astrophysics Data System (ADS)

Gryniuk, Oleksii; Vanderhaeghen, Marc

2017-09-01

We provide an updated analysis of the forward J / ψ -p scattering amplitude, relating its imaginary part to γp -> J / ψp and γp -> c c X cross section data, and calculating its real part through a once-subtracted dispersion relation. From a global fit to both differential and total cross section data, we extract a value for the spin-averaged J / ψ -p s-wave scattering length aψp = 0.046 +/- 0.005 fm, which can be translated into a J / ψ binding energy in nuclear matter Bψ = 2.7 +/- 0.3 MeV. We estimate the forward-backward asymmetry to the γp ->e-e+ p process around the J / ψ resonance, which results from interchanging the leptons in the interference between the J / ψ production and the Bethe-Heitler mechanisms. We show that this asymmetry can reach values around -25%. Its measurement can thus provide a very sensitive observable for a refined extraction of aψp. A preliminary analysis of the ϕ-p forward scattering led to the estimated forward-backward asymmetry reaching values of about -20% for the beam energies E = 2.2 , 4.4 GeV. The suitable kinematics were investigated for the specific setup of HMS and SHMS detectors of Hall C at JLab. Studies for the other JLab experiments (e.g. GlueX, SOLID) are ongoing.

The MOC reflex during active listening to speech.

PubMed

Garinis, Angela C; Glattke, Theodore; Cone, Barbara K

2011-10-01

The purpose of this study was to test the hypothesis that active listening to speech would increase medial olivocochlear (MOC) efferent activity for the right vs. the left ear. Click-evoked otoacoustic emissions (CEOAEs) were evoked by 60-dB p.e. SPL clicks in 13 normally hearing adults in 4 test conditions for each ear: (a) in quiet; (b) with 60-dB SPL contralateral broadband noise; (c) with words embedded (at -3-dB signal-to-noise ratio [SNR]) in 60-dB SPL contralateral noise during which listeners directed attention to the words; and (d) for the same SNR as in the 3rd condition, with words played backwards. There was greater suppression during active listening compared with passive listening that was apparent in the latency range of 6- to 18-ms poststimulus onset. Ear differences in CEOAE amplitude were observed in all conditions, with right-ear amplitudes larger than those for the left. The absolute difference between CEOAE amplitude in quiet and with contralateral noise, a metric of suppression, was equivalent for right and left ears. When the amplitude differences were normalized, suppression was greater for noise presented to the right and the effect measured for a probe in the left ear. The findings support the theory that cortical mechanisms involved in listening to speech affect cochlear function through the MOC efferent system.

The disturbing function for polar Centaurs and transneptunian objects

NASA Astrophysics Data System (ADS)

Namouni, F.; Morais, M. H. M.

2017-10-01

The classical disturbing function of the three-body problem is based on an expansion of the gravitational interaction in the vicinity of nearly coplanar orbits. Consequently, it is not suitable for the identification and study of resonances of the Centaurs and transneptunian objects on nearly polar orbits with the Solar system planets. Here, we provide a series expansion algorithm of the gravitational interaction in the vicinity of polar orbits and produce explicitly the disturbing function to fourth order in eccentricity and inclination cosine. The properties of the polar series differ significantly from those of the classical disturbing function: the polar series can model any resonance, as the expansion order is not related to the resonance order. The powers of eccentricity and inclination of the force amplitude of a p:q resonance do not depend on the value of the resonance order |p - q| but only on its parity. Thus, all even resonance order eccentricity amplitudes are ∝e2 and odd ones ∝e to lowest order in eccentricity e. With the new findings on the structure of the polar disturbing function and the possible resonant critical arguments, we illustrate the dynamics of the polar resonances 1:3, 3:1, 2:9 and 7:9 where transneptunian object 471325 could currently be locked.

Facial Cosmetics Exert a Greater Influence on Processing of the Mouth Relative to the Eyes: Evidence from the N170 Event-Related Potential Component.

PubMed

Tanaka, Hideaki

2016-01-01

Cosmetic makeup significantly influences facial perception. Because faces consist of similar physical structures, cosmetic makeup is typically used to highlight individual features, particularly those of the eyes (i.e., eye shadow) and mouth (i.e., lipstick). Though event-related potentials have been utilized to study various aspects of facial processing, the influence of cosmetics on specific ERP components remains unclear. The present study aimed to investigate the relationship between the application of cosmetic makeup and the amplitudes of the P1 and N170 event-related potential components during facial perception tasks. Moreover, the influence of visual perception on N170 amplitude, was evaluated under three makeup conditions: Eye Shadow, Lipstick, and No Makeup. Electroencephalography was used to monitor 17 participants who were exposed to visual stimuli under each these three makeup conditions. The results of the present study subsequently demonstrated that the Lipstick condition elicited a significantly greater N170 amplitude than the No Makeup condition, while P1 amplitude was unaffected by any of the conditions. Such findings indicate that the application of cosmetic makeup alters general facial perception but exerts no influence on the perception of low-level visual features. Collectively, these results support the notion that the application of makeup induces subtle alterations in the processing of facial stimuli, with a particular effect on the processing of specific facial components (i.e., the mouth), as reflected by changes in N170 amplitude.

Facial Cosmetics Exert a Greater Influence on Processing of the Mouth Relative to the Eyes: Evidence from the N170 Event-Related Potential Component

PubMed Central

Tanaka, Hideaki

2016-01-01

Cosmetic makeup significantly influences facial perception. Because faces consist of similar physical structures, cosmetic makeup is typically used to highlight individual features, particularly those of the eyes (i.e., eye shadow) and mouth (i.e., lipstick). Though event-related potentials have been utilized to study various aspects of facial processing, the influence of cosmetics on specific ERP components remains unclear. The present study aimed to investigate the relationship between the application of cosmetic makeup and the amplitudes of the P1 and N170 event-related potential components during facial perception tasks. Moreover, the influence of visual perception on N170 amplitude, was evaluated under three makeup conditions: Eye Shadow, Lipstick, and No Makeup. Electroencephalography was used to monitor 17 participants who were exposed to visual stimuli under each these three makeup conditions. The results of the present study subsequently demonstrated that the Lipstick condition elicited a significantly greater N170 amplitude than the No Makeup condition, while P1 amplitude was unaffected by any of the conditions. Such findings indicate that the application of cosmetic makeup alters general facial perception but exerts no influence on the perception of low-level visual features. Collectively, these results support the notion that the application of makeup induces subtle alterations in the processing of facial stimuli, with a particular effect on the processing of specific facial components (i.e., the mouth), as reflected by changes in N170 amplitude. PMID:27656161

Linguistic processing in idiopathic generalized epilepsy: an auditory event-related potential study.

PubMed

Henkin, Yael; Kishon-Rabin, Liat; Pratt, Hillel; Kivity, Sara; Sadeh, Michelle; Gadoth, Natan

2003-09-01

Auditory processing of increasing acoustic and linguistic complexity was assessed in children with idiopathic generalized epilepsy (IGE) by using auditory event-related potentials (AERPs) as well as reaction time and performance accuracy. Twenty-four children with IGE [12 with generalized tonic-clonic seizures (GTCSs), and 12 with absence seizures (ASs)] with average intelligence and age-appropriate scholastic skills, uniformly medicated with valproic acid (VPA), and 20 healthy controls, performed oddball discrimination tasks that consisted of the following stimuli: (a) pure tones; (b) nonmeaningful monosyllables that differed by their phonetic features (i.e., phonetic stimuli); and (c) meaningful monosyllabic words from two semantic categories (i.e., semantic stimuli). AERPs elicited by nonlinguistic stimuli were similar in healthy and epilepsy children, whereas those elicited by linguistic stimuli (i.e., phonetic and semantic) differed significantly in latency, amplitude, and scalp distribution. In children with GTCSs, phonetic and semantic processing were characterized by slower processing time, manifested by prolonged N2 and P3 latencies during phonetic processing, and prolongation of all AERPs latencies during semantic processing. In children with ASs, phonetic and semantic processing were characterized by increased allocation of attentional resources, manifested by enhanced N2 amplitudes. Semantic processing also was characterized by prolonged P3 latency. In both patient groups, processing of linguistic stimuli resulted in different patterns of brain-activity lateralization compared with that in healthy controls. Reaction time and performance accuracy did not differ among the study groups. AERPs exposed linguistic-processing deficits related to seizure type in children with IGE. Neurologic follow-up should therefore include evaluation of linguistic functions, and remedial intervention should be provided, accordingly.

Repeatability of short-duration transient visual evoked potentials in normal subjects.

PubMed

Tello, Celso; De Moraes, Carlos Gustavo V; Prata, Tiago S; Derr, Peter; Patel, Jayson; Siegfried, John; Liebmann, Jeffrey M; Ritch, Robert

2010-06-01

To evaluate the within-session and inter-session repeatability of a new, short-duration transient visual evoked potential (SD-tVEP) device on normal individuals, we tested 30 normal subjects (20/20 visual acuity, normal 24-2 SITA Standard VF) with SD-tVEP. Ten of these subjects had their tests repeated within 1-2 months from the initial visit. Synchronized single-channel EEG was recorded using a modified Diopsys Enfant System (Diopsys, Inc., Pine Brook, New Jersey, USA). A checkerboard stimulus was modulated at two reversals per second. Two different contrasts of checkerboard reversal patterns were used: 85% Michelson contrast with a mean luminance of 66.25 cd/m(2) and 10% Michelson contrast with a mean luminance of 112 cd/m(2). Each test lasted 20 s. Both eyes, independently and together, were tested 10 times (5 times at each contrast level). The following information was identified from the filtered N75-P100-N135 complex: N75 amplitude, N75 latency, P100 amplitude, P100 latency, and Delta Amplitude (N75-P100). The median values for each eye's five SD-tVEP parameters were calculated and grouped into two data sets based on contrast level. Mean age was 27.3 +/- 5.2 years. For OD only, the median (95% confidence intervals) of Delta Amplitude (N75-P100) amplitudes at 10% and 85% contrast were 4.6 uV (4.1-5.9) and 7.1 uV (5.15-9.31). The median P100 latencies were 115.2 ms (112.0-117.7) and 104.0 ms (99.9-106.0). There was little within-session variability for any of these parameters. Intraclass correlation coefficients ranged between 0.64 and 0.98, and within subject coefficients of variation were 3-5% (P100 latency) and 15-30% (Delta Amplitude (N75-P100) amplitude). Bland-Altman plots showed good agreement between the first and fifth test sessions (85% contrast Delta Amplitude (N75-P100) delta amplitude, mean difference, 0.48 mV, 95% CI, -0.18-1.12; 85% contrast P100 latency delay, -0.82 ms, 95% CI, -3.12-1.46; 10% contrast Delta Amplitude (N75-P100) amplitude, 0.58 mV, 95% CI, -0.27-1.45; 10% contrast P100 latency delay, -2.05 mV, 95% CI, -5.12-1.01). The inter-eye correlation and agreement were significant for both SD-tVEP amplitude and P100 latency measurements. For the subset of eyes in which the inter-session repeatability was tested, the intraclass correlation coefficients ranged between 0.71 and 0.86 with good agreement shown on Bland-Altman plots. Short-duration transient VEP technology showed good within-session, inter-session repeatability, and good inter-eye correlation and agreement.

Atrial Premature Depolarization-Induced Changes in QRS and T Wave Morphology on Resting Electrocardiograms in Horses.

PubMed

Broux, B; De Clercq, D; Decloedt, A; Van Der Vekens, N; Verheyen, T; Ven, S; Pardon, B; van Loon, G

2016-07-01

The electrocardiographic differentiation between atrial (APDs) and ventricular (VPDs) premature depolarizations is important. P wave prematurity and normal QRS and T wave morphology generally are used as discriminating criteria for APDs. The aim of this study was to determine whether P, Q, R, S, and T wave amplitude, PQ interval, QRS and P wave duration and P and T wave morphology differ between APDs and sinus beats. To determine the relationship between the RR coupling interval and the change in S wave amplitude between sinus beats and APDs. Case-control study. From a modified base-apex configuration of 30 horses with APDs at rest, sinus beat and APD associated preceding RR interval, P, PQ and QRS duration and P, R, S, and T wave amplitudes were measured. Linear mixed models and logistic regression were used to determine the effect of APDs on the ECG variables studied. In comparison to sinus beats, APDs were associated with a significant (P < .001) change in P amplitude (-0.03 ± 0.01 mV) and increase in S (0.20 ± 0.02 mV) and T (0.08 ± 0.03 mV) amplitude. PQ (-20.3 ± 5.2 ms) and RR (-519 ± 14 ms) interval and P duration (-21.1 ± 3.0 ms) decreased (P < .001). APDs were significantly associated with a singular positive P wave (OR: 11.0, P < .001) and were more likely to have a monophasic positive T wave (OR: 9.2, P < .001). A smaller RR coupling interval was associated with an increased relative difference in S amplitude (P < .01). Atrial premature depolarizations may lead to changes in QRS and T wave morphology. Knowledge of these changes is important to avoid interpreting certain APDs as VPDs. Copyright © 2016 The Authors. Journal of Veterinary Internal Medicine published by Wiley Periodicals, Inc. on behalf of the American College of Veterinary Internal Medicine.

Violent offending predicts P300 amplitude.

PubMed

Bernat, Edward M; Hall, Jason R; Steffen, Benjamin V; Patrick, Christopher J

2007-11-01

Prior work has consistently revealed a relationship between antisocial behavior and reduced P300 amplitude. Fewer studies have directly evaluated behavioral indices of aggression and P300, and those that have generally do not account for potential mediating variables such as age, intelligence, and behavioral task performance. The current study assessed the relationship between the total number of convicted violent and non-violent offenses and P300 in a sample of inmates from a medium security state prison. Violent offenses evidenced a robust negative relationship with P300 amplitude, whereas non-violent offenses did not. Additional analyses evaluated age, intelligence, and behavioral task performance as potential mediating variables. Only reaction time significantly predicted P300 amplitude, and mediational analyses showed that this relationship did not account for the violent-offense/P300 relationship. Findings are discussed in terms of personality correlates and neurobiological process related to aggression. There is long-standing interest in the notion that antisocial behavior, and aggression in particular, involves neurobiologically-based deficits in information processing. Neuropsychological research has revealed that antisocial behavior is associated with impaired executive function (c.f. Morgan and Lilienfeld, 2000), and neuroimaging studies have consistently identified frontal lobe abnormalities among violent offenders (Goyer et al., 1994; Raine et al., 1997; Raine et al., 2000; Volkow et al., 1995). Furthermore, research using event-related brain potentials has indicated that antisocial behavior is associated with reduced P300 responses to task-relevant stimuli in target detection tasks (e.g., Bauer et al., 1994; Iacono et al., 2003). These deficits may reflect inefficient neural processing of salient environmental stimuli (Donchin and Coles, 1988), which could potentially contribute to risk for antisocial deviance. Notably, antisocial behavior encompasses both violent and nonviolent transgressions. One unresolved issue is whether P300 amplitude is associated with both violent and non-violent forms of antisocial behavior, or more predominantly with aggressive forms of acting out. Some research has examined P300 response in aggressive individuals specifically (e.g., Barratt et al., 1997); this work has revealed that reduced P300 amplitude is selectively related to impulsive, but not instrumental, aggression. However, this work has not compared associations for aggressive versus non-aggressive offending behavior. Thus, the aim of the present study was to replicate and extend prior research on antisocial behavior and brain response by examining relations between violent and non-violent offenses and P300 amplitude in a sample of adult male inmates. Our prediction was that reduced P300 response would be associated more predominantly with a history of violent offending, and that this effect would be independent of age, intelligence, and task performance effects.

Elevated Production of Nociceptive CC Chemokines and sE-Selectin in Patients With Low Back Pain and the Effects of Spinal Manipulation: A Nonrandomized Clinical Trial.

PubMed

Teodorczyk-Injeyan, Julita A; McGregor, Marion; Triano, John J; Injeyan, Stephen H

2018-01-01

The involvement of inflammatory components in the pathophysiology of low back pain (LBP) is poorly understood. It has been suggested that spinal manipulative therapy (SMT) may exert anti-inflammatory effects. The purpose of this study was to determine the involvement of inflammation-associated chemokines (CC series) in the pathogenesis of nonspecific LBP and to evaluate the effect of SMT on that process. Patients presenting with nonradicular, nonspecific LBP (minimum pain score 3 on 10-point visual analog scale) were recruited according to stringent inclusion criteria. They were evaluated for appropriateness to treat using a high velocity low amplitude manipulative thrust in the lumbar-lumbosacral region. Blood samples were obtained at baseline and following the administration of a series of 6 high velocity low amplitude manipulative thrusts on alternate days over the period of 2 weeks. The in vitro levels of CC chemokine ligands (CCL2, CCL3, and CCL4) production and plasma levels of an inflammatory biomarker, soluble E-selectin (sE-selectin), were determined at baseline and at the termination of treatments 2 weeks later. Compared with asymptomatic controls baseline production of all chemokines was significantly elevated in acute (P=0.004 to <0.0001), and that of CCL2 and CCL4 in chronic LBP patients (P<0.0001). Furthermore, CCL4 production was significantly higher (P<0.0001) in the acute versus chronic LBP group. sE-selectin levels were significantly higher (P=0.003) in chronic but not in acute LBP patients. Following SMT, patient-reported outcomes showed significant (P<0.0001) improvements in visual analog scale and Oswestry Disability Index scores. This was accompanied by a significant decline in CCL3 production (P<0.0001) in both groups of patients. Change scores for CCL4 production differed significantly (P<0.0001) only for the acute LBP cohort, and no effect on the production of CCL2 or plasma sE-selectin levels was noted in either group. The production of chemotactic cytokines is significantly and protractedly elevated in LBP patients. Changes in chemokine production levels, which might be related to SMT, differ in the acute and chronic LBP patient cohorts.

Effect of transcutaneous electrical stimulation amplitude on timing of swallow pressure peaks between healthy young and older adults.

PubMed

Barikroo, Ali; Berretin-Felix, Giedré; Carnaby, Giselle; Crary, Michael

2017-03-01

This study compared the effect of transcutaneous electrical stimulation (TES) amplitude on timing of lingual-palatal and pharyngeal peak pressures during swallowing in healthy younger and older adults. Transcutaneous electrical stimulation amplitude is one parameter that may have different impacts on the neuromotor system and swallowing physiology. One aspect of swallowing physiology influenced by age is the timing of swallowing events. However, the effect of varying TES amplitudes on timing of swallowing physiology is poorly understood, especially in older adults. Thirty-four adults (20 younger and 14 older) swallowed 10 ml of nectar-thick liquid under three TES conditions: no stimulation, low-amplitude stimulation and high-amplitude stimulation. TES was delivered by surface electrodes on the anterior neck. Timing of pressure peaks for lingual-palatal contacts and pharyngeal pressures were measured under each condition. A significant age × stimulation amplitude interaction was identified for the base of tongue (BOT) [F(2,62) = 5.087, p < 0.009] and the hypopharynx (HYPO) [F(2,62) = 3.277, p < 0.044]. At the BOT, low-amplitude TES resulted in slower swallows in the younger adults compared with no TES. In older adults, low-amplitude TES resulted in faster swallows compared with high-amplitude TES. At the HYPO, no significant differences were identified in pressure timing across the three TES amplitudes in both age groups. In each case, low-amplitude TES resulted in faster swallows in older adults compared with younger adults. Transcutaneous electrical stimulation influences pharyngeal pressure timing differently in young and old people, which questions the appropriateness of using a 'one-size-fits-all' TES amplitude for rehabilitating people with dysphagia. © 2015 John Wiley & Sons A/S and The Gerodontology Association. Published by John Wiley & Sons Ltd.

The K-π+ S-wave from the D+→K-π+π+ decay

NASA Astrophysics Data System (ADS)

FOCUS Collaboration; Link, J. M.; Yager, P. M.; Anjos, J. C.; Bediaga, I.; Castromonte, C.; Machado, A. A.; Magnin, J.; Massafferri, A.; de Miranda, J. M.; Pepe, I. M.; Polycarpo, E.; Dos Reis, A. C.; Carrillo, S.; Cuautle, E.; Sánchez-Hernández, A.; Uribe, C.; Vázquez, F.; Agostino, L.; Cinquini, L.; Cumalat, J. P.; Frisullo, V.; O'Reilly, B.; Segoni, I.; Stenson, K.; Butler, J. N.; Cheung, H. W. K.; Chiodini, G.; Gaines, I.; Garbincius, P. H.; Garren, L. A.; Gottschalk, E.; Kasper, P. H.; Kreymer, A. E.; Kutschke, R.; Wang, M.; Benussi, L.; Bianco, S.; Fabbri, F. L.; Zallo, A.; Casimiro, E.; Reyes, M.; Cawlfield, C.; Kim, D. Y.; Rahimi, A.; Wiss, J.; Gardner, R.; Kryemadhi, A.; Chung, Y. S.; Kang, J. S.; Ko, B. R.; Kwak, J. W.; Lee, K. B.; Cho, K.; Park, H.; Alimonti, G.; Barberis, S.; Boschini, M.; Cerutti, A.; D'Angelo, P.; Dicorato, M.; Dini, P.; Edera, L.; Erba, S.; Inzani, P.; Leveraro, F.; Malvezzi, S.; Menasce, D.; Mezzadri, M.; Moroni, L.; Pedrini, D.; Pontoglio, C.; Prelz, F.; Rovere, M.; Sala, S.; Davenport, T. F.; Arena, V.; Boca, G.; Bonomi, G.; Gianini, G.; Liguori, G.; Pegna, D. Lopes; Merlo, M. M.; Pantea, D.; Ratti, S. P.; Riccardi, C.; Vitulo, P.; Göbel, C.; Otalora, J.; Hernandez, H.; Lopez, A. M.; Mendez, H.; Paris, A.; Quinones, J.; Ramirez, J. E.; Zhang, Y.; Wilson, J. R.; Handler, T.; Mitchell, R.; Engh, D.; Hosack, M.; Johns, W. E.; Luiggi, E.; Moore, J. E.; Nehring, M.; Sheldon, P. D.; Vaandering, E. W.; Webster, M.; Sheaff, M.

2009-10-01

Using data from FOCUS (E831) experiment at Fermilab, we present a model independent partial-wave analysis of the K-π+ S-wave amplitude from the decay D+→K-π+π+. The S-wave is a generic complex function to be determined directly from the data fit. The P- and D-waves are parameterized by a sum of Breit-Wigner amplitudes. The measurement of the S-wave amplitude covers the whole elastic range of the K-π+ system.

Alteration of the fast excitatory postsynaptic current by barium in voltage-clamped amphibian sympathetic ganglion cells.

PubMed Central

Connor, E. A.; Parsons, R. L.

1984-01-01

Barium-induced alterations in fast excitatory postsynaptic currents (e.p.s.cs) have been studied in voltage-clamped bullfrog sympathetic ganglion B cells. In the presence of 2-8 mM barium, e.p.s.c. decay was prolonged and in many cells the e.p.s.c. decay phase deviated from a single exponential function. The decay phase in these cases was more accurately described as the sum of two exponential functions. The frequency of occurrence of a complex decay increased both with increasing barium concentration and with hyperpolarization. Miniature e.p.s.c. decay also was prolonged in barium-treated cells. E.p.s.c. amplitude was not markedly affected by barium (2-8 mM) in cells voltage-clamped to -50 mV whereas at -90 mV there was a progressive increase in peak size with increasing barium concentration. In control cells the e.p.s.c.-voltage relationship was linear between -20 and -100 mV; however, this relationship became progressively non-linear with membrane hyperpolarization in barium-treated cells. The e.p.s.c. reversal potential was shifted to a more negative value in the presence of barium. There was a voltage-dependent increase in charge movement during the e.p.s.c. in barium-treated cells which was not present in control cells. We conclude that the voltage-dependent alteration in e.p.s.c. decay time course, peak amplitude and charge movement in barium-treated cells is due to a direct postsynaptic action of barium on the kinetics of receptor-channel gating in postganglionic sympathetic neurones. PMID:6333261

P3 event-related potential impairments in antisocial and psychopathic individuals: a meta-analysis.

PubMed

Gao, Yu; Raine, Adrian

2009-12-01

Prior findings on P3 event-related potential deficits in antisocial populations are mixed and it has been suggested that these abnormalities may not apply to psychopaths. A meta-analysis of 38 studies (total N=2616) was conducted to investigate the relationship of P3 measures to antisocial behavior. Reduced P3 amplitudes (d=0.252, p<.001) and longer P3 latencies (d=0.130, p=.019) were significantly associated with antisocial behavior across all electrode sites, and when using both normal and non-normal control groups. A significant moderating effect of electrode site indicated longer latencies at Fz but not Pz. Compared to non-psychopathic offenders, psychopathic offenders showed P3 amplitudes impairments in standard oddball tasks, but not other tasks. Findings suggest that reduced P3 amplitudes and prolonged P3 latencies may reflect inefficient deployment of neural resources in processing cognitive task-relevant information in individuals characterized with generic antisocial behavior (i.e., aggression, antisocial personality disorder, conduct disorder/oppositional-defiant disorder, and psychopathy), whereas this association in psychopaths may be moderated by the type of tasks.

Neuromuscular performance of lower limbs during voluntary and reflex activity in power- and endurance-trained athletes.

PubMed

Kyröläinen, H; Komi, P V

1994-01-01

Neural, mechanical and muscle factors influence muscle force production. This study was therefore, designed to compare possible differences in the function of the neuromuscular system among differently adapted subjects. A group of 11 power-trained athletes and 10 endurance-trained athletes volunteered as subjects for this study. Maximal voluntary isometric force and the rate of force production of the knee extensor and the plantar flexor muscles were measured. In addition, basic reflex function was measured in the two experimental conditions. The power athletes produced higher voluntary forces (P < 0.01-0.001) with higher rates for force production (P < 0.001) by both muscle groups measured. Unexpectedly, however, no differences were noticed in the electromyogram time curves between the groups. During reflex activity, the endurance group demonstrated higher sensitivity to the mechanical stimuli, i.e. the higher reflex amplitude caused a higher rate of reflex force development, and the reflex amplitude correlated with the averaged angular velocity. The differences in the isometric conditions could be explained by obviously different muscle fibre distribution, by different amounts of muscle mass, by possible differences in the force transmission from individual myofibrils to the skeletal muscle and by specificity of training. In addition, differences in nervous system structure and muscle spindle properties could explain the observed differences in reflex activity between the two groups.

The relation between schizotypy and early attention to rejecting interactions: The influence of neuroticism

PubMed Central

Premkumar, Preethi; Onwumere, Juliana; Albert, Jacobo; Kessel, Dominique; Kumari, Veena; Kuipers, Elizabeth; Carretié, Luis

2015-01-01

Abstract Objectives: Schizotypy relates to rejection sensitivity (anxiety reflecting an expectancy of social exclusion) and neuroticism (excessive evaluation of negative emotions). Positive schizotypy (e.g., perceptual aberrations and odd beliefs) and negative schizotypy (e.g., social and physical anhedonia) could relate to altered attention to rejection because of neuroticism. Methods: Forty-one healthy individuals were assessed on positive and negative schizotypy and neuroticism, and event-related potentials during rejecting, accepting and neutral scenes. Participants were categorised into high, moderate and low neuroticism groups. Using temporo-spatial principal components analyses, P200 (peak latency =290 ms) and P300 amplitudes (peak latency = 390 ms) were measured, reflecting mobilisation of attention and early attention, respectively. Results: Scalp-level and cortical source analysis revealed elevated fronto-parietal N300/P300 amplitude and P200-related dorsal anterior cingulate current density during rejection than acceptance/neutral scenes. Positive schizotypy related inversely to parietal P200 amplitude during rejection. Negative schizotypy related positively to P200 middle occipital current density. Negative schizotypy related positively to parietal P300, where the association was stronger in high and moderate, than low, neuroticism groups. Conclusions: Positive and negative schizotypy relate divergently to attention to rejection. Positive schizotypy attenuates, but negative schizotypy increases rejection-related mobilisation of attention. Negative schizotypy increases early attention to rejection partly due to elevated neuroticism. PMID:26452584

Low-amplitude pulses to the circulation through periodic acceleration induces endothelial-dependent vasodilatation.

PubMed

Uryash, Arkady; Wu, Heng; Bassuk, Jorge; Kurlansky, Paul; Sackner, Marvin A; Adams, Jose A

2009-06-01

Low-amplitude pulses to the vasculature increase pulsatile shear stress to the endothelium. This activates endothelial nitric oxide (NO) synthase (eNOS) to promote NO release and endothelial-dependent vasodilatation. Descent of the dicrotic notch on the arterial pulse waveform and a-to-b ratio (a/b; where a is the height of the pulse amplitude and b is the height of the dicrotic notch above the end-diastolic level) reflects vasodilator (increased a/b) and vasoconstrictor effects (decreased a/b) due to NO level change. Periodic acceleration (pG(z)) (motion of the supine body head to foot on a platform) provides systemic additional pulsatile shear stress. The purpose of this study was to determine whether or not pG(z) applied to rats produced endothelial-dependent vasodilatation and increased NO production, and whether the latter was regulated by the Akt/phosphatidylinositol 3-kinase (PI3K) pathway. Male rats were anesthetized and instrumented, and pG(z) was applied. Sodium nitroprusside, N(G)-nitro-l-arginine methyl ester (l-NAME), and wortmannin (WM; to block Akt/PI3K pathway) were administered to compare changes in a/b and mean aortic pressure. Descent of the dicrotic notch occurred within 2 s of initiating pG(z). Dose-dependent increase of a/b and decrease of mean aortic pressure took place with SNP. l-NAME produced a dose-dependent rise in mean aortic pressure and decrease of a/b, which was blunted with pG(z). In the presence of WM, pG(z) did not decrease aortic pressure or increase a/b. WM also abolished the pG(z) blunting effect on blood pressure and a/b of l-NAME-treated animals. eNOS expression was increased in aortic tissue after pG(z). This study indicates that addition of low-amplitude pulses to circulation through pG(z) produces endothelial-dependent vasodilatation due to increased NO in rats, which is mediated via activation of eNOS, in part, by the Akt/PI3K pathway.

Effects of temperature and electric field on order parameters in ferroelectric hexagonal manganites

NASA Astrophysics Data System (ADS)

Zhang, C. X.; Yang, K. L.; Jia, P.; Lin, H. L.; Li, C. F.; Lin, L.; Yan, Z. B.; Liu, J.-M.

2018-03-01

In Landau-Devonshire phase transition theory, the order parameter represents a unique property for a disorder-order transition at the critical temperature. Nevertheless, for a phase transition with more than one order parameter, such behaviors can be quite different and system-dependent in many cases. In this work, we investigate the temperature (T) and electric field (E) dependence of the two order parameters in improper ferroelectric hexagonal manganites, addressing the phase transition from the high-symmetry P63/mmc structure to the polar P63cm structure. It is revealed that the trimerization as the primary order parameter with two components: the trimerization amplitude Q and phase Φ, and the spontaneous polarization P emerging as the secondary order parameter exhibit quite different stability behaviors against various T and E. The critical exponents for the two parameters Q and P are 1/2 and 3/2, respectively. As temperature increases, the window for the electric field E enduring the trimerization state will shrink. An electric field will break the Z2 part of the Z2×Z3 symmetry. The present work may shed light on the complexity of the vortex-antivortex domain structure evolution near the phase transition temperature.

Somatosensory spatial attention modulates amplitudes, latencies, and latency jitter of laser-evoked brain potentials.

PubMed

Franz, Marcel; Nickel, Moritz M; Ritter, Alexander; Miltner, Wolfgang H R; Weiss, Thomas

2015-04-01

Several studies provided evidence that the amplitudes of laser-evoked potentials (LEPs) are modulated by attention. However, previous reports were based on across-trial averaging of LEP responses at the expense of losing information about intertrial variability related to attentional modulation. The aim of this study was to investigate the effects of somatosensory spatial attention on single-trial parameters (i.e., amplitudes, latencies, and latency jitter) of LEP components (N2 and P2). Twelve subjects participated in a sustained spatial attention paradigm while noxious laser stimuli (left hand) and noxious electrical stimuli (right hand) were sequentially delivered to the dorsum of the respective hand with nonnoxious air puffs randomly interspersed within the sequence of noxious stimuli. Participants were instructed to mentally count all stimuli (i.e., noxious and nonnoxious) applied to the attended location. Laser stimuli, presented to the attended hand (ALS), elicited larger single-trial amplitudes of the N2 component compared with unattended laser stimuli (ULS). In contrast, single-trial amplitudes of the P2 component were not significantly affected by spatial attention. Single-trial latencies of the N2 and P2 were significantly smaller for ALS vs. ULS. Additionally, the across-trial latency jitter of the N2 component was reduced for ALS. Conversely, the latency jitter of the P2 component was smaller for ULS compared with ALS. With the use of single-trial analysis, the study provided new insights into brain dynamics of LEPs related to spatial attention. Our results indicate that single-trial parameters of LEP components are differentially modulated by spatial attention. Copyright © 2015 the American Physiological Society.

Influence of the Dirac-Hartree-Fock starting potential on the parity-nonconserving electric-dipole-transition amplitudes in cesium and thallium

NASA Technical Reports Server (NTRS)

Perger, W. F.; Das, B. P.

1987-01-01

The parity-nonconserving electric-dipole-transition amplitudes for the 6s1/2-7s1/2 transition in cesium and the 6p1/2-7p1/2 transition in thallium have been calculated by the Dirac-Hartree-Fock method. The effects of using different Dirac-Hartree-Fock atomic core potentials are examined and the transition amplitudes for both the length and velocity gauges are given. It is found that the parity-nonconserving transition amplitudes exhibit a greater dependence on the starting potential for thallium than for cesium.

Direct reconstruction of p-p elastic scattering amplitudes at 1.8 and 2.1 GeV

NASA Astrophysics Data System (ADS)

Ghahramany, Nader; Forozani, Ghasem

2000-06-01

The direct reconstruction of the proton-proton elastic-scattering complex amplitudes is carried out at 1.8 and 2.1 GeV. Five independent amplitudes both in helicity and transversity frame were obtained by using an extensive set of data measured recently at SATURNE II and by the EDDA (COSY) Collaboration. The real and imaginary parts of the amplitudes are plotted versus different interpolated c.m. angles for both frames. Four distinct sets of solutions exist, one of which is chosen on the basis of minimum χ2.

Clarifying relations between dispositional aggression and brain potential response: overlapping and distinct contributions of impulsivity and stress reactivity.

PubMed

Venables, Noah C; Patrick, Christopher J; Hall, Jason R; Bernat, Edward M

2011-03-01

Impulsive-aggressive individuals exhibit deficits in amplitude of the P3 brain potential response, however, it remains unclear how separable dispositional traits account for this association. The current study sought to clarify the basis of this association by examining contributions of trait impulsiveness and stress reactivity to the observed relationship between dispositional aggression and amplitude of the P3 brain potential response in a visual novelty-oddball procedure. A significant negative association was found between aggressiveness and amplitude of P3 response to both target and novel stimuli over frontal-central scalp sites. Impulsivity showed a parallel inverse relationship with P3 amplitude, attributable to its overlap with dispositional aggression. In contrast, stress reactivity did not exhibit a zero-order association with P3 amplitude, but modestly predicted P3 in a positive direction after accounting for its overlap with aggression. Results are discussed in terms of their implications for individual difference variables and brain processes underlying impulsive-aggressive behavior. Copyright © 2011 Elsevier B.V. All rights reserved.

Blocked versus randomized presentation modes differentially modulate feedback-related negativity and P3b amplitudes

PubMed Central

Pfabigan, Daniela M.; Zeiler, Michael; Lamm, Claus; Sailer, Uta

2014-01-01

Objective Electrophysiological studies on feedback processing typically use a wide range of feedback stimuli which might not always be comparable. The current study investigated whether two indicators of feedback processing – feedback-related negativity (FRN) and P3b – differ for feedback stimuli with explicit (facial expressions) or assigned valence information (symbols). In addition, we assessed whether presenting feedback in either a trial-by-trial or a block-wise fashion affected these ERPs. Methods EEG was recorded in three experiments while participants performed a time estimation task and received two different types of performance feedback. Results Only P3b amplitudes varied consistently in response to feedback type for both presentation types. Moreover, the blocked feedback type presentation yielded more distinct FRN peaks, higher effect sizes, and a significant relation between FRN amplitudes and behavioral task performance measures. Conclusion Both stimulus type and presentation mode may provoke systematic changes in feedback-related ERPs. The current findings point at important potential confounds that need to be controlled for when designing FRN or P3b studies. Significance Studies investigating P3b amplitudes using mixed types of stimuli have to be interpreted with caution. Furthermore, we suggest implementing a blocked presentation format when presenting different feedback types within the same experiment. PMID:24144779

P300 in individuals with sensorineural hearing loss.

PubMed

Reis, Ana Cláudia Mirandola Barbosa; Frizzo, Ana Claudia Figueiredo; Isaac, Myriam de Lima; Garcia, Cristiane Fregonesi Dutra; Funayama, Carolina Araújo Rodrigues; Iório, Maria Cecília Martinelli

2015-01-01

Behavioral and electrophysiological auditory evaluations contribute to the understanding of the auditory system and of the process of intervention. To study P300 in subjects with severe or profound sensorineural hearing loss. This was a descriptive cross-sectional prospective study. It included 29 individuals of both genders with severe or profound sensorineural hearing loss without other type of disorders, aged 11 to 42 years; all were assessed by behavioral audiological evaluation and auditory evoked potentials. A recording of the P3 wave was obtained in 17 individuals, with a mean latency of 326.97ms and mean amplitude of 3.76V. There were significant differences in latency in relation to age and in amplitude according to degree of hearing loss. There was a statistically significant association of the P300 results with the degrees of hearing loss (p=0.04), with the predominant auditory communication channels (p<0.0001), and with time of hearing loss. P300 can be recorded in individuals with severe and profound congenital sensorineural hearing loss; it may contribute to the understanding of cortical development and is a good predictor of the early intervention outcome. Copyright © 2014 Associação Brasileira de Otorrinolaringologia e Cirurgia Cérvico-Facial. Published by Elsevier Editora Ltda. All rights reserved.

Altered Cortical Responsiveness to Pain Stimuli after High Frequency Electrical Stimulation of the Skin in Patients with Persistent Pain after Inguinal Hernia Repair

PubMed Central

van den Broeke, Emanuel N.; Koeslag, Lonneke; Arendsen, Laura J.; Nienhuijs, Simon W.; Rosman, Camiel; van Rijn, Clementina M.; Wilder-Smith, Oliver H. G.; van Goor, Harry

2013-01-01

Background High Frequency electrical Stimulation (HFS) of the skin induces enhanced brain responsiveness expressed as enhanced Event-Related Potential (ERP) N1 amplitude to stimuli applied to the surrounding unconditioned skin in healthy volunteers. The aim of the present study was to investigate whether this enhanced ERP N1 amplitude could be a potential marker for altered cortical sensory processing in patients with persistent pain after surgery. Materials and Methods Nineteen male patients; 9 with and 10 without persistent pain after inguinal hernia repair received HFS. Before, directly after and thirty minutes after HFS evoked potentials and the subjective pain intensity were measured in response to electric pain stimuli applied to the surrounding unconditioned skin. Results The results show that, thirty minutes after HFS, the ERP N1 amplitude observed at the conditioned arm was statistically significantly larger than the amplitude at the control arm across all patients. No statistically significant differences were observed regarding ERP N1 amplitude between patients with and without persistent pain. However, thirty minutes after HFS we did observe statistically significant differences of P2 amplitude at the conditioned arm between the two groups. The P2 amplitude decreased in comparison to baseline in the group of patients with pain. Conclusion The ERP N1 effect, induced after HFS, was not different between patients with vs. without persistent pain. The decreasing P2 amplitude was not observed in the patients without pain and also not in the previous healthy volunteer study and thus might be a marker for altered cortical sensory processing in patients with persistent pain after surgery. PMID:24376568

Finger tapping analysis in patients with Parkinson's disease and atypical parkinsonism.

PubMed

Djurić-Jovičić, Milica; Petrović, Igor; Ječmenica-Lukić, Milica; Radovanović, Saša; Dragašević-Mišković, Nataša; Belić, Minja; Miler-Jerković, Vera; Popović, Mirjana B; Kostić, Vladimir S

2016-08-01

The goal of this study was to investigate repetitive finger tapping patterns in patients with Parkinson's disease (PD), progressive supranuclear palsy-Richardson syndrome (PSP-R), or multiple system atrophy of parkinsonian type (MSA-P). The finger tapping performance was objectively assessed in PD (n=13), PSP-R (n=15), and MSA-P (n=14) patients and matched healthy controls (HC; n=14), using miniature inertial sensors positioned on the thumb and index finger, providing spatio-temporal kinematic parameters. The main finding was the lack or only minimal progressive reduction in amplitude during the finger tapping in PSP-R patients, similar to HC, but significantly different from the sequence effect (progressive decrement) in both PD and MSA-P patients. The mean negative amplitude slope of -0.12°/cycle revealed less progression of amplitude decrement even in comparison to HC (-0.21°/cycle, p=0.032), and particularly from PD (-0.56°/cycle, p=0.001), and MSA-P patients (-1.48°/cycle, p=0.003). No significant differences were found in the average finger separation amplitudes between PD, PSP-R and MSA-P patients (pmsa-pd=0.726, pmsa-psp=0.363, ppsp-pd=0.726). The lack of clinically significant sequence effect during finger tapping differentiated PSP-R from both PD and MSA-P patients, and might be specific for PSP-R. The finger tapping kinematic parameter of amplitude slope may be a neurophysiological marker able to differentiate particular forms of parkinsonism. Copyright © 2016 Elsevier Ltd. All rights reserved.

Polarization and Out-of-Plane Observables in the γ^*NarrowΔ Transition

NASA Astrophysics Data System (ADS)

Kaloskamis, N. I.

1998-10-01

The H(e,e^' p)π^0, H(e,e^' p)π^0 and H(e,e^' π^+)n reactions have been studied at Bates during the past three years. Polarization observables have been measured for the first time in order to extract the Coulomb quadrupole amplitude of the γ^*NarrowΔ transition, by isolating it from that due to background processes. The detection equipment included a focal plane polarimeter (FPP) in the first experiment, and out-of-plane spectrometers (OOPS) in the second. Measurements were made at Q^2=0.127 (GeV/c)^2, invariant masses of W=1170, 1232, 1294 MeV and angles θ_pq^cm of up to 61^o. Data will be presented for the total cross section and the proton recoil polarization (P_n). Combined with sequencial measurements of the space asymmetry (A_LT), they provide clear discrimination among available electroproduction models and do not confirm a recent reportfootnote F. Kalleicher et al., Z. Phys. A359, 201 (1997) of a large Coulomb quadrupole amplitude. Preliminary data of the helicity asymmetry (A_LT^'), measured simultaneously using two OOPS modules, will also be presented.

In-vivo corneal pulsation in relation to in-vivo intraocular pressure and corneal biomechanics assessed in-vitro. An animal pilot study.

PubMed

Rogala, Maja M; Danielewska, Monika E; Antończyk, Agnieszka; Kiełbowicz, Zdzisław; Rogowska, Marta E; Kozuń, Marta; Detyna, Jerzy; Iskander, D Robert

2017-09-01

The aim was to ascertain whether the characteristics of the corneal pulse (CP) measured in-vivo in a rabbit eye change after short-term artificial increase of intraocular pressure (IOP) and whether they correlate with corneal biomechanics assessed in-vitro. Eight New Zealand white rabbits were included in this study and were anesthetized. In-vivo experiments included simultaneous measurements of the CP signal, registered with a non-contact method, IOP, intra-arterial blood pressure, and blood pulse (BPL), at the baseline and short-term elevated IOP. Afterwards, thickness of post-mortem corneas was determined and then uniaxial tensile tests were conducted leading to estimates of their Young's modulus (E). At the baseline IOP, backward stepwise regression analyses were performed in which successively the ocular biomechanical, biometric and cardiovascular predictors were separately taken into account. Results of the analysis revealed that the 3rd CP harmonic can be statistically significantly predicted by E and central corneal thickness (Models: R 2  = 0.662, p < 0.005 and R 2  = 0.832, p < 0.001 for the signal amplitude and power, respectively). The 1st CP harmonic can be statistically significantly predicted by the amplitude and power of the 1st BPL harmonic (Models: R 2  = 0.534, p = 0.015 and R 2  = 0.509, p < 0.018, respectively). For elevated IOP, non-parametric analysis indicated significant differences for the power of the 1st CP harmonic (Kruskal-Wallis test; p = 0.031) and for the mean, systolic and diastolic blood pressures (p = 0.025, p = 0.019, p = 0.033, respectively). In conclusion, for the first time, the association between parameters of the CP signal in-vivo and corneal biomechanics in-vitro was confirmed. In particular, spectral analysis revealed that higher amplitude and power of the 3rd CP harmonic indicates higher corneal stiffness, while the 1st CP harmonic correlates positively with the corresponding harmonic of the BPL signal. Copyright © 2017 Elsevier Ltd. All rights reserved.

Neutral Pion Electroproduction in the Δ Resonance Region

DOE Office of Scientific and Technical Information (OSTI.GOV)

Villano, Anthony

2007-11-01

The electroproduction of baryon resonances at high Q 2 is examined. Analysis focuses on the Δ(1232) resonance via exclusive pseudoscalar meson production of π 0 particles. Differential cross sections are extracted for exclusive π 0 electroproduction. In the central invariant mass (W) region the cross sections are used to extract resonant multipole amplitudes. In particular, the ratio of the electric quadrupole to magnetic dipole amplitudes (E2/M1) will be discussed for the Δ(1232) resonance. The transition to pQCD is discussed in terms of E2/M1 and other multipoles. The helicity amplitude A 3/2 can be used as a baryon helicity conservation meter in this context and will be discussed. The fast shrinking of the resonant contribution in the Δ region is observed at this high momentum transfer. Apart from the observables related to pQCD scaling, the transition form factor Gmore » $$*\\atop{M}$$ is extracted along with the scalar to magnetic dipole ratio C2/M1.« less

Increased Evoked Potentials and Behavioral Indices in Response to Pain Among Individuals with Intellectual Disability.

PubMed

Benromano, Tali; Pick, Chaim G; Granovsky, Yelena; Defrin, Ruth

2017-09-01

Previous studies on the sensitivity and reactivity to pain of individuals with intellectual disability (ID) are inconsistent. The inconsistency may result from the reliance on self-reports and facial expressions of pain that are subject to internal and external biases. The aim was therefore to evaluate the reactivity to pain of individuals with ID by recording pain-evoked potentials (EPs), here for the first time, and testing their association with behavioral pain indices. Forty-one healthy adults, 16 with mild-moderate ID and 25 controls. Subjects received series of phasic heat stimuli and rated their pain on self-report scales. Changes in facial expressions and in pain EPs were recorded and analyzed offline. Pain self-reports, facial expressions, and the N2P2 amplitudes of the EPs exhibited stimulus-response relationship with stimulation intensity in both groups. The facial expressions and N2P2 amplitudes of individuals with ID were increased and N2P2 latency prolonged compared with controls. N2P2 amplitudes correlated with self-reports only in controls. Individuals with ID are hypersensitive/reactive to pain, a finding bearing clinical implications. Although pain EPs may reflect a somewhat different aspect of pain than the behavioral indices do, there is evidence to support their use to record pain in noncommunicative individuals, pending further validation. © 2017 American Academy of Pain Medicine. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com

The utility of event-related potentials (ERPs) in understanding food-related cognition: A systematic review and recommendations.

PubMed

Carbine, Kaylie A; Rodeback, Rebekah; Modersitzki, Erin; Miner, Marshall; LeCheminant, James D; Larson, Michael J

2018-05-19

Daily dietary decisions have the potential to impact our physical, mental, and emotional health. Event-related potentials (ERPs) can provide insight into cognitive processes, such as attention, working memory, and inhibitory control, that may influence the food-related decisions we make on a daily basis. We conducted a systematic review of the food-related cognition and ERP research in order to summarize the extant literature, identify future research questions, synthesize how food-related ERP components relate to eating habits and appetite, and demonstrate the utility of ERPs in examining food-related cognition. Forty-three articles were systematically extracted. In general, results indicated food cues compared to less palatable foods or neutral cues elicited greater ERP amplitudes reflecting early or late attention allocation (e.g., increased P2, P3, late positive potential amplitudes). Food cues were associated with increased frontocentral P3 and N2 ERP amplitudes compared to neutral or less palatable food cues, suggesting increased recruitment of inhibitory control and conflict monitoring resources. However, there was significant heterogeneity in the literature, as experimental tasks, stimuli, and examined ERP components varied widely across studies, and therefore replication studies are needed. In-depth research is also needed to establish how food-related ERPs differ by BMI groups and relate to real-world eating habits and appetite, in order to establish the ecological validity. Copyright © 2018. Published by Elsevier Ltd.

[A study of sympathetic skin response to the damage of autonomic nerves function in patients with chronic N-hexane poisoning].

PubMed

Situ, Jie; Wu, Jian; Wang, Jing-lin; Zhu, De-xiang; Zhang, Jian-jie; Liu, Wei-wei; Qin, Zhuo-hui

2012-05-01

To study the sympathetic skin response (SSR) to the effects of N-hexane on autonomic nerves function in patients with chronic N-hexane poisoning. The subjects in present study included 30 controls and 37 cases with chronic N-hexane poisoning. Also 37 patients were divided into 3 subgroups (mild, moderate and severe poisoning) according to diagnostic criteria of occupational diseases. All subjects were examined by SSR test and nerve conduction velocity (NCV) test. All patients were reexamined by SSR and NCV every 1 ∼ 2 months. The differences in SSR parameters (latency, amplitude) among groups were observed. In the severe poisoning subgroup, the changes of SSR and NCV parameters (conduction velocity, amplitude) in different poisoning stages were observed. There were significant differences in SSR latency of upper extremity among groups and the significant differences in SSR amplitude of upper and lower extremity among groups (P < 0.05). No significant differences in SSR parameters were found between the adjacent groups (P > 0.05). There were significant differences in SSR latency of upper extremity during different periods and the significant differences in SSR amplitude of upper and lower extremity during different periods among all groups (P < 0.05). The change of SSR parameters consistent with that in NCV. The longest SSR latency of upper extremity and the smallest SSR amplitudes of upper and lower extremity appears 1 - 2 months earlier than that of the smallest action potential amplitude. The damage of autonomic nerves induced by N-hexane increased with poisoning progresses. The damage of autonomic nerves corresponded with the damage of myelin sheath of large myelinated nerves, but which appeared 1 - 2 months earlier than the damage of axon of large myelinated nerves. SSR test may serve as a method to detect the damage of autonomic nerves function in patients with chronic N-hexane poisoning.

P3 event-related potential amplitude and the risk for disinhibitory disorders in adolescent boys.

PubMed

Iacono, William G; Carlson, Scott R; Malone, Stephen M; McGue, Matthew

2002-08-01

The children of parents who abuse alcohol typically show reduced amplitude of the P3 event-related potential wave. We determined if this effect was present in a population-based sample of older adolescent boys, whether it was associated with paternal antisocial personality and drug use, and whether it appeared in youth with childhood externalizing and substance use disorders. A statewide sample of 502 male youth, identified from Minnesota birth records as members of twin pairs, had their P3 amplitude measured, using a visual oddball paradigm when they were approximately 17 years old. Structured clinical interviews covering attention-deficit/hyperactivity disorder, conduct disorder, oppositional defiant disorder, antisocial personality disorder, and substance use disorders were administered in person to the youth and his parents at the time of the P3 assessment and again to the youth 3 years later. Reduced P3 was associated with disorders and paternal risk for disorders, reflecting a behavioral disinhibition spectrum that included attention-deficit/hyperactivity disorder, oppositional defiant disorder, conduct disorder, antisocial personality disorder, alcoholism, nicotine dependence, and illicit drug abuse and dependence. Reduced P3 at age 17 predicted the development of substance use disorders at age 20. Most effect sizes associated with these group differences exceeded 0.70, indicating medium to moderately large group differences. Maternal alcoholism and substance use during pregnancy were unrelated to P3 amplitude in offspring. Small amplitude P3 may indicate genetic risk for a dimension of disinhibiting psychiatric disorders, including childhood externalizing, adult antisocial personality disorder, and substance use disorders.

Quantum effects in amplitude death of coupled anharmonic self-oscillators

NASA Astrophysics Data System (ADS)

Amitai, Ehud; Koppenhöfer, Martin; Lörch, Niels; Bruder, Christoph

2018-05-01

Coupling two or more self-oscillating systems may stabilize their zero-amplitude rest state, therefore quenching their oscillation. This phenomenon is termed "amplitude death." Well known and studied in classical self-oscillators, amplitude death was only recently investigated in quantum self-oscillators [Ishibashi and Kanamoto, Phys. Rev. E 96, 052210 (2017), 10.1103/PhysRevE.96.052210]. Quantitative differences between the classical and quantum descriptions were found. Here, we demonstrate that for quantum self-oscillators with anharmonicity in their energy spectrum, multiple resonances in the mean phonon number can be observed. This is a result of the discrete energy spectrum of these oscillators, and is not present in the corresponding classical model. Experiments can be realized with current technology and would demonstrate these genuine quantum effects in the amplitude death phenomenon.

Waveform modeling of the seismic response of a mid-ocean ridge axial melt sill

NASA Astrophysics Data System (ADS)

Xu, Min; Stephen, R. A.; Canales, J. Pablo

2017-12-01

Seismic reflections from axial magma lens (AML) are commonly observed along many mid-ocean ridges, and are thought to arise from the negative impedance contrast between a solid, high-speed lid and the underlying low-speed, molten or partially molten (mush) sill. The polarity of the AML reflection ( P AML P) at vertical incidence and the amplitude vs offset (AVO) behavior of the AML reflections (e.g., P AML P and S-converted P AML S waves) are often used as a diagnostic tool for the nature of the low-speed sill. Time-domain finite difference calculations for two-dimensional laterally homogeneous models show some scenarios make the interpretation of melt content from partial-offset stacks of P- and S-waves difficult. Laterally heterogeneous model calculations indicate diffractions from the edges of the finite-width AML reducing the amplitude of the AML reflections. Rough seafloor and/or a rough AML surface can also greatly reduce the amplitude of peg-leg multiples because of scattering and destructive interference. Mid-crustal seismic reflection events are observed in the three-dimensional multi-channel seismic dataset acquired over the RIDGE-2000 Integrated Study Site at East Pacific Rise (EPR, cruise MGL0812). Modeling indicates that the mid-crustal seismic reflection reflections are unlikely to arise from peg-leg multiples of the AML reflections, P-to- S converted phases, or scattering due to rough topography, but could probably arise from deeper multiple magma sills. Our results support the identification of Marjanović et al. (Nat Geosci 7(11):825-829, 2014) that a multi-level complex of melt lenses is present beneath the axis of the EPR.

Hexamethonium- and methyllycaconitine-induced changes in acetylcholine release from rat motor nerve terminals.

PubMed

Tian, L; Prior, C; Dempster, J; Marshall, I G

1997-11-01

1. The neuronal nicotinic receptor antagonists hexamethonium and methyllycaconitine (MLA) have been used to study the putative prejunctional nicotinic ACh receptors (AChRs) mediating a negative-feedback control of ACh release from motor nerve terminals in voltage-clamped rat phrenic nerve/ hemidiaphragm preparations. 2. Hexamethonium (200 microM), but not MLA (0.4-2.0 microM), decreased the time constant of decay of both endplate currents (e.p.cs) and miniature endplate currents (m.e.p.cs), indicating endplate ion channel block with hexamethonium. However, driving function analysis and reconvolution of e.p.cs and m.e.p.cs indicated that this ion channel block did not compromise the analysis of e.p.c. quantal content. 3. At low frequencies of stimulation (0.5-2 Hz), hexamethonium (200 microM) and MLA (2.0 microM) increased e.p.c. quantal content by 30-40%. At high frequencies (50-150 Hz) neither compound affected e.p.c. quantal content. All effects on quantal content were paralleled by changes in the size of the pool of quanta available for release. 4. The low frequency augmentation of e.p.c. quantal content by hexamethonium was absent when extracellular [Ca2+] was lowered from 2.0 to 0.5 mM. 5. At the concentrations studied, MLA and hexamethonium produced a small (10-20%) decrease in the peak amplitude of m.e.p.cs. 6. Neither apamin (100 nM) nor charybdotoxin (80 nM) had effects on spontaneous or nerve evoked current amplitudes at any frequency of stimulation. Thus the ability of nicotinic antagonists to augment e.p.c. quantal content is not due to inhibition of Ca(2+)-activated K(+)-channels. 7. We suggest that hexamethonium and MLA increase evoked ACh release by blocking prejunctional nicotinic AChRs. These receptors exert a negative feedback control over evoked ACh release and are probably of the alpha-bungarotoxin-insensitive neuronal type.

Hexamethonium- and methyllycaconitine-induced changes in acetylcholine release from rat motor nerve terminals

PubMed Central

Tian, >Lijun; Prior, Chris; Dempster, John; Marshall, Ian G

1997-01-01

The neuronal nicotinic receptor antagonists hexamethonium and methyllycaconitine (MLA) have been used to study the putative prejunctional nicotinic ACh receptors (AChRs) mediating a negative-feedback control of ACh release from motor nerve terminals in voltage-clamped rat phrenic nerve/hemidiaphragm preparations. Hexamethonium (200 μM), but not MLA (0.4–2.0 μM), decreased the time constant of decay of both endplate currents (e.p.cs) and miniature endplate currents (m.e.p.cs), indicating endplate ion channel block with hexamethonium. However, driving function analysis and reconvolution of e.p.cs and m.e.p.cs indicated that this ion channel block did not compromise the analysis of e.p.c. quantal content. At low frequencies of stimulation (0.5–2 Hz), hexamethonium (200 μM) and MLA (2.0 μM) increased e.p.c. quantal content by 30–40%. At high frequencies (50–150 Hz) neither compound affected e.p.c. quantal content. All effects on quantal content were paralleled by changes in the size of the pool of quanta available for release. The low frequency augmentation of e.p.c. quantal content by hexamethonium was absent when extracellular [Ca2+] was lowered from 2.0 to 0.5 mM. At the concentrations studied, MLA and hexamethonium produced a small (10–20%) decrease in the peak amplitude of m.e.p.cs. Neither apamin (100 nM) nor charybdotoxin (80 nM) had effects on spontaneous or nerve evoked current amplitudes at any frequency of stimulation. Thus the ability of nicotinic antagonists to augment e.p.c. quantal content is not due to inhibition of Ca2+-activated K+-channels. We suggest that hexamethonium and MLA increase evoked ACh release by blocking prejunctional nicotinic AChRs. These receptors exert a negative feedback control over evoked ACh release and are probably of the α-bungarotoxin-insensitive neuronal type. PMID:9401765

The impact of cognitive control, incentives, and working memory load on the P3 responses of externalizing prisoners.

PubMed

Baskin-Sommers, Arielle R; Krusemark, Elizabeth A; Curtin, John J; Lee, Christopher; Vujnovich, Aleice; Newman, Joseph P

2014-02-01

The P3 amplitude reduction is one of the most common correlates of externalizing. However, few studies have used experimental manipulations designed to challenge different cognitive functions in order to clarify the processes that impact this reduction. To examine factors moderating P3 amplitude in trait externalizing, we administered an n-back task that manipulated cognitive control demands, working memory load, and incentives to a sample of male offenders. Offenders with high trait externalizing scores did not display a global reduction in P3 amplitude. Rather, the negative association between trait externalizing and P3 amplitude was specific to trials involving inhibition of a dominant response during infrequent stimuli, in the context of low working memory load, and incentives for performance. In addition, we discuss the potential implications of these findings for externalizing-related psychopathologies. The results complement and expand previous work on the process-level dysfunction contributing to externalizing-related deficits in P3. Copyright © 2013 Elsevier B.V. All rights reserved.

[Differential effects of attention deficit/hyperactivity disorder subtypes in event-related potentials].

PubMed

Tamayo-Orrego, Lukas; Osorio Forero, Alejandro; Quintero Giraldo, Lina Paola; Parra Sánchez, José Hernán; Varela, Vilma; Restrepo, Francia

2015-01-01

To better understand the neurophysiological substrates in attention deficit/hyperactivity disorder (ADHD), a study was performed on of event-related potentials (ERPs) in Colombian patients with inattentive and combined ADHD. A case-control, cross-sectional study was designed. The sample was composed of 180 subjects between 5 and 15 years of age (mean, 9.25±2.6), from local schools in Manizales. The sample was divided equally in ADHD or control groups and the subjects were paired by age and gender. The diagnosis was made using the DSM-IV-TR criteria, the Conners and WISC-III test, a psychiatric interview (MINIKID), and a medical evaluation. ERPs were recorded in a visual and auditory passive oddball paradigm. Latency and amplitude of N100, N200 and P300 components for common and rare stimuli were used for statistical comparisons. ADHD subjects show differences in the N200 amplitude and P300 latency in the auditory task. The N200 amplitude was reduced in response to visual stimuli. ADHD subjects with combined symptoms show a delayed P300 in response to auditory stimuli, whereas inattentive subjects exhibited differences in the amplitude of N100 and N200. Combined ADHD patients showed longer N100 latency and smaller N200-P300 amplitude compared to inattentive ADHD subjects. The results show differences in the event-related potentials between combined and inattentive ADHD subjects. Copyright © 2014 Asociación Colombiana de Psiquiatría. Publicado por Elsevier España. All rights reserved.

Age-related differences in early novelty processing: Using PCA to parse the overlapping anterior P2 and N2 components

PubMed Central

Daffner, Kirk R.; Alperin, Brittany R.; Mott, Katherine K.; Tusch, Erich; Holcomb, Phillip J.

2015-01-01

Previous work demonstrated age-associated increases in the anterior P2 and age-related decreases in the anterior N2 in response to novel stimuli. Principal component analysis (PCA) was used to determine if the inverse relationship between these components was due to their temporal and spatial overlap. PCA revealed an early anterior P2, sensitive to task relevance, and a late anterior P2, responsive to novelty, both exhibiting age-related amplitude increases. A PCA factor representing the anterior N2, sensitive to novelty, exhibited age-related amplitude decreases. The late P2 and N2 to novels inversely correlated. Larger late P2 amplitude to novels was associated with better behavioral performance. Age-related differences in the anterior P2 and N2 to novel stimuli likely represent age-associated changes in independent cognitive operations. Enhanced anterior P2 activity (indexing augmentation in motivational salience) may be a compensatory mechanism for diminished anterior N2 activity (indexing reduced ability of older adults to process ambiguous representations). PMID:25596483

Blocked versus randomized presentation modes differentially modulate feedback-related negativity and P3b amplitudes.

PubMed

Pfabigan, Daniela M; Zeiler, Michael; Lamm, Claus; Sailer, Uta

2014-04-01

Electrophysiological studies on feedback processing typically use a wide range of feedback stimuli which might not always be comparable. The current study investigated whether two indicators of feedback processing - feedback-related negativity (FRN) and P3b - differ for feedback stimuli with explicit (facial expressions) or assigned valence information (symbols). In addition, we assessed whether presenting feedback in either a trial-by-trial or a block-wise fashion affected these ERPs. EEG was recorded in three experiments while participants performed a time estimation task and received two different types of performance feedback. Only P3b amplitudes varied consistently in response to feedback type for both presentation types. Moreover, the blocked feedback type presentation yielded more distinct FRN peaks, higher effect sizes, and a significant relation between FRN amplitudes and behavioral task performance measures. Both stimulus type and presentation mode may provoke systematic changes in feedback-related ERPs. The current findings point at important potential confounds that need to be controlled for when designing FRN or P3b studies. Studies investigating P3b amplitudes using mixed types of stimuli have to be interpreted with caution. Furthermore, we suggest implementing a blocked presentation format when presenting different feedback types within the same experiment. Copyright © 2013 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.

Effects of contralateral white noise stimulation on distortion product otoacoustic emissions in myasthenic patients.

PubMed

Di Girolamo, S; d'Ecclesia, A; Quaranta, N; Garozzo, A; Evoli, A; Paludetti, G

2001-12-01

Myasthenia gravis (MG) induces a reduction of transient evoked otoacoustic emissions (TEOAEs) and distortion product otoacoustic emissions (DPOAEs) that reverses partially after administration of an acetylcholinesterase (AChE) inhibitor. In normal subjects a contralateral acoustic stimulation (CAS) produces an amplitude reduction of TEOAEs and DPOAEs. This effect, called contralateral suppression (CS), is mediated by the efferent auditory system. Twenty subjects affected by MG underwent DPOAE recording with and without contralateral white noise in a drug-free baseline period ('basal') and 1 h ('post') after administration of a reversible AChE inhibitor. In 'basal' condition CAS did not induce significant DPOAE amplitude changes but a paradoxical slight increase was observed. After drug administration, CAS produced a significant decrease of DPOAE amplitudes for middle frequencies (f(2) between 1306 and 2600 Hz). In normal controls CAS caused a significant decrease (P<0.001) for all frequencies. The amount of CS in controls and in the MG 'post' condition was not significantly different. The increased acetylcholine (ACh) availability following drug consumption seems to partially restore outer hair cell function and enhances their electromotility; a further influx of ACh due to CAS yields to restoration of the CS. These findings also suggest that DPOAEs may be useful in the diagnosis of MG and for monitoring the effectiveness of treatment.

Minimum Electric Field Exposure for Seizure Induction with Electroconvulsive Therapy and Magnetic Seizure Therapy.

PubMed

Lee, Won H; Lisanby, Sarah H; Laine, Andrew F; Peterchev, Angel V

2017-05-01

Lowering and individualizing the current amplitude in electroconvulsive therapy (ECT) has been proposed as a means to produce stimulation closer to the neural activation threshold and more focal seizure induction, which could potentially reduce cognitive side effects. However, the effect of current amplitude on the electric field (E-field) in the brain has not been previously linked to the current amplitude threshold for seizure induction. We coupled MRI-based E-field models with amplitude titrations of motor threshold (MT) and seizure threshold (ST) in four nonhuman primates (NHPs) to determine the strength, distribution, and focality of stimulation in the brain for four ECT electrode configurations (bilateral, bifrontal, right-unilateral, and frontomedial) and magnetic seizure therapy (MST) with cap coil on vertex. At the amplitude-titrated ST, the stimulated brain subvolume (23-63%) was significantly less than for conventional ECT with high, fixed current (94-99%). The focality of amplitude-titrated right-unilateral ECT (25%) was comparable to cap coil MST (23%), demonstrating that ECT with a low current amplitude and focal electrode placement can induce seizures with E-field as focal as MST, although these electrode and coil configurations affect differently specific brain regions. Individualizing the current amplitude reduced interindividual variation in the stimulation focality by 40-53% for ECT and 26% for MST, supporting amplitude individualization as a means of dosing especially for ECT. There was an overall significant correlation between the measured amplitude-titrated ST and the prediction of the E-field models, supporting a potential role of these models in dosing of ECT and MST. These findings may guide the development of seizure therapy dosing paradigms with improved risk/benefit ratio.

Neuromuscular response amplitude to mechanical stimulation using large-array surface electromyography in participants with and without chronic low back pain.

PubMed

Pagé, Isabelle; Nougarou, François; Descarreaux, Martin

2016-04-01

The present study aimed to compare the neuromuscular response under various mechanical stimulations of the lumbar spine in participants with and without chronic low back pain (cLBP). Four mechanical stimulations, characterized by forces ranging from 75 to 225N, were delivered using a servo-controlled linear actuator motor to the L3 spinous process of 25 healthy participants and 26 participants with cLBP. Lumbar neuromuscular responses were recorded using 64-electrodes large surface electromyography arrays. Between-group differences in the dose-response relationship (neuromuscular response amplitude according to each force level) were assessed using mixed model ANOVAs. No differences between groups were shown (all p values>.05). A significant linear relationship was observed between forces and neuromuscular response amplitudes (p<.001) indicating an increase in response amplitudes with increasing stimulation force. Responses were observed throughout the lumbar region with highest response amplitudes in the vicinity of the contacted vertebra. The neuromuscular response amplitude triggered by localized lumbar mechanical stimulations does not differ between participants with and without cLBP. Moreover, even though stimulations were delivered at specific spinal segment, a neuromuscular response, although rapidly decreasing, was observed in areas distant from the contact site. Copyright © 2016 Elsevier Ltd. All rights reserved.

Initial-value problem for the Gardner equation applied to nonlinear internal waves

NASA Astrophysics Data System (ADS)

Rouvinskaya, Ekaterina; Kurkina, Oxana; Kurkin, Andrey; Talipova, Tatiana; Pelinovsky, Efim

2017-04-01

The Gardner equation is a fundamental mathematical model for the description of weakly nonlinear weakly dispersive internal waves, when cubic nonlinearity cannot be neglected. Within this model coefficients of quadratic and cubic nonlinearity can both be positive as well as negative, depending on background conditions of the medium, where waves propagate (sea water density stratification, shear flow profile) [Rouvinskaya et al., 2014, Kurkina et al., 2011, 2015]. For the investigation of weakly dispersive behavior in the framework of nondimensional Gardner equation with fixed (positive) sign of quadratic nonlinearity and positive or negative cubic nonlinearity {eq1} partial η/partial t+6η( {1± η} )partial η/partial x+partial ^3η/partial x^3=0, } the series of numerical experiments of initial-value problem was carried out for evolution of a bell-shaped impulse of negative polarity (opposite to the sign of quadratic nonlinear coefficient): {eq2} η(x,t=0)=-asech2 ( {x/x0 } ), for which amplitude a and width x0 was varied. Similar initial-value problem was considered in the paper [Trillo et al., 2016] for the Korteweg - de Vries equation. For the Gardner equation with different signs of cubic nonlinearity the initial-value problem for piece-wise constant initial condition was considered in detail in [Grimshaw et al., 2002, 2010]. It is widely known, for example, [Pelinovsky et al., 2007], that the Gardner equation (1) with negative cubic nonlinearity has a family of classic solitary wave solutions with only positive polarity,and with limiting amplitude equal to 1. Therefore evolution of impulses (2) of negative polarity (whose amplitudes a were varied from 0.1 to 3, and widths at the level of a/2 were equal to triple width of solitons with the same amplitude for a 1) was going on a universal scenario with the generation of nonlinear Airy wave. For the Gardner equation (1) with the positive cubic nonlinearity coefficient there exist two one-parametric families of solitons (family with positive polarity, and family with negative polarity bounded below by the amplitude of 2) and two-parametric family of breathers (oscillatory wave packets). In this case varying amplitude and width of bell-shaped initial impulse leads to plenty of different evolutionary scenarios with the generation of solitary waves, breathers, solibores and nonlinear Airy wave in their various combinations. Statistical analysis of the wave field in time shows almost permanent substantial exceedance of the level of the significant wave height in some position in spatial coordinate. Evolution of Fourier spectrum of the wave field is also analyzed, and its behavior after a long time of initial wave evolution demonstrates the power asymptotic for small wave numbers and exponential asymptotic for large wave numbers. The presented results of research are obtained with the support of the grant of the President of the Russian Federation for state support of the young Russian scientists - Candidates of Sciences (MK-5208.2016.5) and Russian Foundation for Basic Research grant 16-05-00049. References: Grimshaw R., Pelinovsky D., Pelinovsky E and Slunyaev A. Generation of large-amplitude solitons in the extended Korteweg-de Vries equation // Chaos, 2002. - V.12. - No 4. - 1070-1076. Grimshaw, R., Slunyaev, A., and Pelinovsky, E. Generation of solitons and breathers in the extended Korteweg-de Vries equation with positive cubic nonlinearity //Chaos, 2010. - vol. 20.-013102. Kurkina O.E., Kurkin A.A., Soomere T., Pelinovsky E.N., Rouvinskaya E.A. Higher-order (2+4) Korteweg-de Vries - like equation for interfacial waves in a symmetric three-layer fluid // Physics of Fluids, 2011. - Volume 23. - Issue 11. - p.116602--1--13. Kurkina O., Rouvinskaya E., Talipova T., Kurkin A., Pelinovsky E. Nonlinear disintegration of sine wave in the framework of the Gardner equation // Physica D: Nonlinear Phenomena, 2015. - doi:10.1016/j.physd.2015.12.007. Pelinovsky E., Polukhina O., Slunyaev A., Talipova T. Internal solitary waves // Chapter 4 in the book ``Solitary Waves in Fluids''. WIT Press. Southampton, Boston. 2007. P. 85 - 110. Rouvinskaya E., Kurkina O., Kurkin A. Dynamics of nonlinear internal gravity waves in layered fluids // NNSTU n.a. R.E. Alekseev Press - Nizhny Novgorod, 2014 - 160 p. [In Russian] Trillo S., Klein M., Clauss G., Onorato M. Observation of dispersive shock waves developing from initial depressions in shallow water // Physica D, 2016. - http://dx.doi.org/10.1016/j.physd.2016.01.007.

ERP differences between processing of physical characteristics and personality attributes

PubMed Central

2012-01-01

Background Limited data from behavioral and brain-imaging studies indicate that personality traits and physical characteristics are processed differently by the brain. Additionally, electrophysiological results of studies comparing the processing of positive and negative words have produced mixed results. It is therefore not clear how physical and personality attributes with emotional valence (i.e., positive and negative valence) are processed. Thus, this study aimed to examine the neural activity associated with words describing personality traits and physical characteristics with positive or negative emotional valence using Event Related Potentials (ERPs). Methods A sample of 15 healthy adults (7 men, 8 women) participated in a computerized word categorization task. Participants were asked to categorize visual word stimuli as physical characteristics or personality traits, while ERPs were recorded synchronously. Results Behavioral reaction times to negative physical stimuli were shorter compared to negative personality words, however reaction times did not significantly differ for positive stimuli. Electrophysiological results showed that personality stimuli elicited larger P2 and LPC (Late Positive Component) amplitudes compared to physical stimuli, regardless of negative or positive valence. Moreover, negative as compared with positive stimuli elicited larger P2 and LPC amplitudes. Conclusion Personality and physical stimuli were processed differently regardless of positive or negative valence. These findings suggest that personality traits and physical characteristics are differentially classified and are associated with different motivational significance. PMID:22967478

Lipid-lowering drugs (statins) and peripheral neuropathy.

PubMed

Emad, Mohammadreza; Arjmand, Hosein; Farpour, Hamid Reza; Kardeh, Bahareh

2018-03-01

Peripheral neuropathy is a disorder with often unknown causes. Some drugs, including statins, are proposed to be among the causes of peripheral neuropathy. This study aimed at evaluating this condition by electrodiagnostic study among patients who had received statins. This case-control study was conducted in Shiraz, Iran in 2015, and included 39 patients aged 35-55 who had received statins for at least 6 months, and 39 healthy matched controls. Using electrodiagnosis, the sensory and motor wave features (amplitude, latency and nerve conduction velocity) of the peripheral nerves (Median, Ulnar, Tibial, Sural, and Peroneal) were evaluated among the subjects. Data were analyzed using SPSS software and p<0.05 was considered statistically significant. Regarding the occurrence of neuropathy, there were no significant differences in any of the definitions presented for peripheral neuropathy. However, the difference was close to significance for one definition [2 abnormalities in 2 nerves (p=0.055)]. Regarding mean values of the features, significant differences were observed in two features: amplitude of the peroneal motor nerve (p=0.048) and amplitude of the sural sensory nerve (p=0.036). Since statins are widely used, awareness regarding their side-effects would lead to better treatment. Even though no significant differences were found between the groups regarding the occurrence of peripheral neuropathy, there were significant differences in amplitudes of the sural sensory response and the peroneal motor response. This indicates the involvement of peripheral nerves. Therefore, we recommend that patients and physicians should be informed about the possible symptoms of this condition.

Vocal responses of austral forest frogs to amplitude and degradation patterns of advertisement calls.

PubMed

Penna, Mario; Moreno-Gómez, Felipe N; Muñoz, Matías I; Cisternas, Javiera

2017-07-01

Degradation phenomena affecting animal acoustic signals may provide cues to assess the distance of emitters. Recognition of degraded signals has been extensively demonstrated in birds, and recently studies have also reported detection of degraded patterns in anurans that call at or above ground level. In the current study we explore the vocal responses of the syntopic burrowing male frogs Eupsophus emiliopugini and E. calcaratus from the South American temperate forest to synthetic conspecific calls differing in amplitude and emulating degraded and non-degraded signal patterns. The results show a strong dependence of vocal responses on signal amplitude, and a general lack of differential responses to signals with different pulse amplitude modulation depths in E. emiliopugini and no effect of relative amplitude of harmonics in E. calcaratus. Such limited discrimination of signal degradation patterns from non-degraded signals is likely related to the burrowing habits of these species. Shelters amplify outgoing and incoming conspecific vocalizations, but do not counteract signal degradation to an extent comparable to calling strategies used by other frogs. The limited detection abilities and resultant response permissiveness to degraded calls in these syntopic burrowing species would be advantageous for animals communicating in circumstances in which signal alteration prevails. Copyright © 2017 Elsevier B.V. All rights reserved.

Esophageal dysmotility in children with eosinophilic esophagitis: a study using prolonged esophageal manometry.

PubMed

Nurko, Samuel; Rosen, Rachel; Furuta, Glenn T

2009-12-01

The pathophysiology of dysphagia in patients with eosinophilic esophagitis (EoE) is unknown but may be related to abnormal esophageal motor function. Symptoms rarely occur during stationary esophageal manometry, so it has been difficult to establish an association between symptoms and motor events. Our aim was to evaluate esophageal motor function in children with EoE with the use of stationary manometry and ambulatory prolonged esophageal manometry and pH-metry (PEMP). PEMP was performed in children with EoE and compared with controls and children with gastroesophageal reflux disease (GERD). Peristalsis was considered effective when the esophageal contractions had a normal amplitude and propagation. Results are expressed as mean+/-s.e. Seventeen patients with EoE, 13 with GERD, and 11 controls were studied. Values are expressed as mean+/-s.e. Stationary manometry identified abnormal peristalsis in 41% of children with EoE. During PEMP, children with EoE had an increased number of isolated (16.7+/-3.8 vs. 9.5+/-1.6 vs. 6.5+/-1.1; P<0.03) and high-amplitude contractions (4.1+/-1.2 vs. 1.8+/-0.8 vs. 0.1+/-0.1; P<0.03), and higher percentage ineffective peristalsis both during fasting (70.5%+/-2.5 vs. 57.8%+/-3.0 vs. 53.8%+/-1.9; P<0.05) and during meals (68.4+/-3.4 vs. 55.3+/-2.8 vs. 48.1+/-2.8; P<0.05) when compared with children with GERD and controls. Thirteen patients with EoE experienced 21 episodes of dysphagia, and all correlated with simultaneous abnormal motor function. PEMP allowed the detection of ineffective peristalsis in children with EoE. Symptoms observed in children with EoE may be related to esophageal motor dysfunction.

Relationship between size and latency of action potentials in human muscle sympathetic nerve activity.

PubMed

Salmanpour, Aryan; Brown, Lyndon J; Steinback, Craig D; Usselman, Charlotte W; Goswami, Ruma; Shoemaker, J Kevin

2011-06-01

We employed a novel action potential detection and classification technique to study the relationship between the recruitment of sympathetic action potentials (i.e., neurons) and the size of integrated sympathetic bursts in human muscle sympathetic nerve activity (MSNA). Multifiber postganglionic sympathetic nerve activity from the common fibular nerve was collected using microneurography in 10 healthy subjects at rest and during activation of sympathetic outflow using lower body negative pressure (LBNP). Burst occurrence increased with LBNP. Integrated burst strength (size) varied from 0.22 ± 0.07 V at rest to 0.28 ± 0.09 V during LBNP. Sympathetic burst size (i.e., peak height) was directly related to the number of action potentials within a sympathetic burst both at baseline (r = 0.75 ± 0.13; P < 0.001) and LBNP (r = 0.75 ± 0.12; P < 0.001). Also, the amplitude of detected action potentials within sympathetic bursts was directly related to the increased burst size at both baseline (r = 0.59 ± 0.16; P < 0.001) and LBNP (r = 0.61 ± 0.12; P < 0.001). In addition, the number of detected action potentials and the number of distinct action potential clusters within a given sympathetic burst were correlated at baseline (r = 0.7 ± 0.1; P < 0.001) and during LBNP (r = 0.74 ± 0.03; P < 0.001). Furthermore, action potential latency (i.e., an inverse index of neural conduction velocity) was decreased as a function of action potential size at baseline and LBNP. LBNP did not change the number of action potentials and unique clusters per sympathetic burst. It was concluded that there exists a hierarchical pattern of recruitment of additional faster conducting neurons of larger amplitude as the sympathetic bursts become stronger (i.e., larger amplitude bursts). This fundamental pattern was evident at rest and was not altered by the level of baroreceptor unloading applied in this study.

P300-based brain-computer interface (BCI) event-related potentials (ERPs): People with amyotrophic lateral sclerosis (ALS) vs. age-matched controls.

PubMed

McCane, Lynn M; Heckman, Susan M; McFarland, Dennis J; Townsend, George; Mak, Joseph N; Sellers, Eric W; Zeitlin, Debra; Tenteromano, Laura M; Wolpaw, Jonathan R; Vaughan, Theresa M

2015-11-01

Brain-computer interfaces (BCIs) aimed at restoring communication to people with severe neuromuscular disabilities often use event-related potentials (ERPs) in scalp-recorded EEG activity. Up to the present, most research and development in this area has been done in the laboratory with young healthy control subjects. In order to facilitate the development of BCI most useful to people with disabilities, the present study set out to: (1) determine whether people with amyotrophic lateral sclerosis (ALS) and healthy, age-matched volunteers (HVs) differ in the speed and accuracy of their ERP-based BCI use; (2) compare the ERP characteristics of these two groups; and (3) identify ERP-related factors that might enable improvement in BCI performance for people with disabilities. Sixteen EEG channels were recorded while people with ALS or healthy age-matched volunteers (HVs) used a P300-based BCI. The subjects with ALS had little or no remaining useful motor control (mean ALS Functional Rating Scale-Revised 9.4 (±9.5SD) (range 0-25)). Each subject attended to a target item as the items in a 6×6 visual matrix flashed. The BCI used a stepwise linear discriminant function (SWLDA) to determine the item the user wished to select (i.e., the target item). Offline analyses assessed the latencies, amplitudes, and locations of ERPs to the target and non-target items for people with ALS and age-matched control subjects. BCI accuracy and communication rate did not differ significantly between ALS users and HVs. Although ERP morphology was similar for the two groups, their target ERPs differed significantly in the location and amplitude of the late positivity (P300), the amplitude of the early negativity (N200), and the latency of the late negativity (LN). The differences in target ERP components between people with ALS and age-matched HVs are consistent with the growing recognition that ALS may affect cortical function. The development of BCIs for use by this population may begin with studies in HVs but also needs to include studies in people with ALS. Their differences in ERP components may affect the selection of electrode montages, and might also affect the selection of presentation parameters (e.g., matrix design, stimulation rate). P300-based BCI performance in people severely disabled by ALS is similar to that of age-matched control subjects. At the same time, their ERP components differ to some degree from those of controls. Attention to these differences could contribute to the development of BCIs useful to those with ALS and possibly to others with severe neuromuscular disabilities. Copyright © 2015 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.

The effect of spectral filters on VEP and alpha-wave responses.

PubMed

Willeford, Kevin T; Fimreite, Vanessa; Ciuffreda, Kenneth J

2016-01-01

Spectral filters are used to treat light sensitivity in individuals with traumatic brain injury (TBI); however, the effect of these filters on normal visual function has not been elucidated. Thus, the current study aimed to determine the effect of spectral filters on objectively-measured visual-evoked potential (VEP) and alpha-wave responses in the visually-normal population. The full-field (15°H×17°V), pattern-reversal VEP (20' check size, mean luminance 52cd/m(2)) was administered to 20 visually-normal individuals. They were tested with four Intuitive-Colorimeter-derived, broad-band, spectral filters (i.e., gray/neutral density, blue, yellow, and red), which produced similar luminance values for the test stimulus. The VEP N75 and P100 latencies, and VEP amplitude, were recorded. Power spectrum analysis was used to derive the respective powers at each frequency, and peak frequency, for the selected 9-11Hz components of the alpha band. Both N75 and P100 latencies increased with the addition of each filter when compared to baseline. Additionally, each filter numerically reduced intra-session amplitude variability relative to baseline. There were no significant effects on either the mean VEP amplitude or alpha wave parameters. The Intuitive Colorimeter filters significantly increased both N75 and P100 latencies, an effect which is primarily attributable (∼75%) to luminance, and in some cases, specific spectral effects (e.g., blue and red). VEP amplitude and alpha power were not significantly affected. These findings provide an important reference to which either amplitude or power changes in light-sensitive, younger clinical groups can be compared. Copyright © 2015 Spanish General Council of Optometry. Published by Elsevier Espana. All rights reserved.

The effect of spectral filters on VEP and alpha-wave responses

PubMed Central

Willeford, Kevin T.; Fimreite, Vanessa; Ciuffreda, Kenneth J.

2015-01-01

Purpose Spectral filters are used to treat light sensitivity in individuals with traumatic brain injury (TBI); however, the effect of these filters on normal visual function has not been elucidated. Thus, the current study aimed to determine the effect of spectral filters on objectively-measured visual-evoked potential (VEP) and alpha-wave responses in the visually-normal population. Methods The full-field (15°H × 17°V), pattern-reversal VEP (20′ check size, mean luminance 52 cd/m2) was administered to 20 visually-normal individuals. They were tested with four Intuitive-Colorimeter-derived, broad-band, spectral filters (i.e., gray/neutral density, blue, yellow, and red), which produced similar luminance values for the test stimulus. The VEP N75 and P100 latencies, and VEP amplitude, were recorded. Power spectrum analysis was used to derive the respective powers at each frequency, and peak frequency, for the selected 9–11 Hz components of the alpha band. Results Both N75 and P100 latencies increased with the addition of each filter when compared to baseline. Additionally, each filter numerically reduced intra-session amplitude variability relative to baseline. There were no significant effects on either the mean VEP amplitude or alpha wave parameters. Conclusions The Intuitive Colorimeter filters significantly increased both N75 and P100 latencies, an effect which is primarily attributable (∼75%) to luminance, and in some cases, specific spectral effects (e.g., blue and red). VEP amplitude and alpha power were not significantly affected. These findings provide an important reference to which either amplitude or power changes in light-sensitive, younger clinical groups can be compared. PMID:26293969

Differences in transient outward currents of feline endocardial and epicardial myocytes.

PubMed

Furukawa, T; Myerburg, R J; Furukawa, N; Bassett, A L; Kimura, S

1990-11-01

Whole-cell voltage-clamp experiments were performed on enzymatically dissociated single ventricular myocytes harvested from feline endocardial and epicardial surfaces. The studies were designed to test the hypothesis that the differences in the amplitude of transient outward current (Ito) contribute to the difference in action potential configuration between endocardial and epicardial myocytes. In the control state, action potentials recorded from epicardial cells demonstrated a prominent notch between phases 1 and 2, and membrane current recordings displayed a prominent Ito, whereas in endocardial cells the notch in action potentials and Ito were small. External application of 4-aminopyridine (2 mM) reduced the amplitudes of notch and Ito in epicardial cells but not in endocardial cells. After application of 4-aminopyridine (2 mM) and caffeine (5 mM), the notch and Ito were abolished completely in both endocardial and epicardial cells. The first component of Ito (Ito1) was present in all epicardial cells studied (n = 20); it was absent in 12 of the 20 endocardial cells, and a small Ito1 was present in the remaining eight endocardial cells. The mean amplitude of Ito1 was significantly greater in epicardial than in endocardial cells. At a test voltage of +80 mV, the amplitude of Ito1 was 102.0 +/- 47.7 pA/pF in epicardial cells and 3.3 +/- 3.3 pA/pF in endocardial cells (p less than 0.01). The second component of Ito (Ito2) was present in all endocardial (n = 30) and epicardial (n = 30) cells studied. The amplitude of Ito2 was significantly greater in epicardial than in endocardial cells.(ABSTRACT TRUNCATED AT 250 WORDS)

Does the Dumbbell-Carrying Position Change the Muscle Activity in Split Squats and Walking Lunges?

PubMed

Stastny, Petr; Lehnert, Michal; Zaatar, Amr M Z; Svoboda, Zdenek; Xaverova, Zuzana

2015-11-01

The forward walking lunge (WL) and split squat (SSq) are similar exercises that have differences in the eccentric phase, and both can be performed in the ipsilateral or contralateral carrying conditions. This study aimed to determine the effects of dumbbell-carrying position on the kinematics and electromyographic (EMG) amplitudes of the gluteus medius (Gmed), vastus medialis (VM), vastus lateralis (VL), and biceps femoris during WLs and SSqs. The resistance-trained (RT) and the non-resistance-trained (NT) groups (both n = 14) performed ipsilateral WLs, contralateral WLs, ipsilateral SSqs, and contralateral SSqs in a randomized order in a simulated training session. The EMG amplitude, expressed as a percentage of the maximal voluntary isometric contraction (%MVIC), and the kinematics, expressed as the range of motion (ROM) of the hip and knee, were measured during 5 repetition maximum for both legs. The repeated measure analyses of variance showed significant differences between the RT and NT groups. The NT group showed a smaller knee flexion ROM (p < 0.001, η = 0.36) during both types of WLs, whereas the RT group showed a higher eccentric Gmed amplitude (p < 0.001, η = 0.46) during all exercises and a higher eccentric VL amplitude (p < 0.001, η = 0.63) during contralateral WLs. Further differences were found between contralateral and ipsilateral WLs in both the RT (p < 0.001, η = 0.69) and NT groups (p < 0.001, η = 0.80), and contralateral WLs resulted in higher eccentric Gmed amplitudes. Contralateral WLs highly activated the Gmed (90% MVIC); therefore, this exercise can increase the Gmed maximal strength. The ipsilateral loading condition did not increase the Gmed or VM activity in the RT or NT group.

Effects of Type of Agreement Violation and Utterance Position on the Auditory Processing of Subject-Verb Agreement: An ERP Study

PubMed Central

Dube, Sithembinkosi; Kung, Carmen; Peter, Varghese; Brock, Jon; Demuth, Katherine

2016-01-01

Previous ERP studies have often reported two ERP components—LAN and P600—in response to subject-verb (S-V) agreement violations (e.g., the boys *runs). However, the latency, amplitude and scalp distribution of these components have been shown to vary depending on various experiment-related factors. One factor that has not received attention is the extent to which the relative perceptual salience related to either the utterance position (verbal inflection in utterance-medial vs. utterance-final contexts) or the type of agreement violation (errors of omission vs. errors of commission) may influence the auditory processing of S-V agreement. The lack of reports on these effects in ERP studies may be due to the fact that most studies have used the visual modality, which does not reveal acoustic information. To address this gap, we used ERPs to measure the brain activity of Australian English-speaking adults while they listened to sentences in which the S-V agreement differed by type of agreement violation and utterance position. We observed early negative and positive clusters (AN/P600 effects) for the overall grammaticality effect. Further analysis revealed that the mean amplitude and distribution of the P600 effect was only significant in contexts where the S-V agreement violation occurred utterance-finally, regardless of type of agreement violation. The mean amplitude and distribution of the negativity did not differ significantly across types of agreement violation and utterance position. These findings suggest that the increased perceptual salience of the violation in utterance final position (due to phrase-final lengthening) influenced how S-V agreement violations were processed during sentence comprehension. Implications for the functional interpretation of language-related ERPs and experimental design are discussed. PMID:27625617

Effects of Type of Agreement Violation and Utterance Position on the Auditory Processing of Subject-Verb Agreement: An ERP Study.

PubMed

Dube, Sithembinkosi; Kung, Carmen; Peter, Varghese; Brock, Jon; Demuth, Katherine

2016-01-01

Previous ERP studies have often reported two ERP components-LAN and P600-in response to subject-verb (S-V) agreement violations (e.g., the boys (*) runs). However, the latency, amplitude and scalp distribution of these components have been shown to vary depending on various experiment-related factors. One factor that has not received attention is the extent to which the relative perceptual salience related to either the utterance position (verbal inflection in utterance-medial vs. utterance-final contexts) or the type of agreement violation (errors of omission vs. errors of commission) may influence the auditory processing of S-V agreement. The lack of reports on these effects in ERP studies may be due to the fact that most studies have used the visual modality, which does not reveal acoustic information. To address this gap, we used ERPs to measure the brain activity of Australian English-speaking adults while they listened to sentences in which the S-V agreement differed by type of agreement violation and utterance position. We observed early negative and positive clusters (AN/P600 effects) for the overall grammaticality effect. Further analysis revealed that the mean amplitude and distribution of the P600 effect was only significant in contexts where the S-V agreement violation occurred utterance-finally, regardless of type of agreement violation. The mean amplitude and distribution of the negativity did not differ significantly across types of agreement violation and utterance position. These findings suggest that the increased perceptual salience of the violation in utterance final position (due to phrase-final lengthening) influenced how S-V agreement violations were processed during sentence comprehension. Implications for the functional interpretation of language-related ERPs and experimental design are discussed.

Analysis of Lung Tumor Motion in a Large Sample: Patterns and Factors Influencing Precise Delineation of Internal Target Volume

DOE Office of Scientific and Technical Information (OSTI.GOV)

Knybel, Lukas; VŠB-Technical University of Ostrava, Ostrava; Cvek, Jakub, E-mail: Jakub.cvek@fno.cz

Purpose/Objective: To evaluate lung tumor motion during respiration and to describe factors affecting the range and variability of motion in patients treated with stereotactic ablative radiation therapy. Methods and Materials: Log file analysis from online respiratory tumor tracking was performed in 145 patients. Geometric tumor location in the lungs, tumor volume and origin (primary or metastatic), sex, and tumor motion amplitudes in the superior-inferior (SI), latero-lateral (LL), and anterior-posterior (AP) directions were recorded. Tumor motion variability during treatment was described using intrafraction/interfraction amplitude variability and tumor motion baseline changes. Tumor movement dependent on the tumor volume, position and origin, andmore » sex were evaluated using statistical regression and correlation analysis. Results: After analysis of >500 hours of data, the highest rates of motion amplitudes, intrafraction/interfraction variation, and tumor baseline changes were in the SI direction (6.0 ± 2.2 mm, 2.2 ± 1.8 mm, 1.1 ± 0.9 mm, and −0.1 ± 2.6 mm). The mean motion amplitudes in the lower/upper geometric halves of the lungs were significantly different (P<.001). Motion amplitudes >15 mm were observed only in the lower geometric quarter of the lungs. Higher tumor motion amplitudes generated higher intrafraction variations (R=.86, P<.001). Interfraction variations and baseline changes >3 mm indicated tumors contacting mediastinal structures or parietal pleura. On univariate analysis, neither sex nor tumor origin (primary vs metastatic) was an independent predictive factor of different movement patterns. Metastatic lesions in women, but not men, showed significantly higher mean amplitudes (P=.03) and variability (primary, 2.7 mm; metastatic, 4.9 mm; P=.002) than primary tumors. Conclusion: Online tracking showed significant irregularities in lung tumor movement during respiration. Motion amplitude was significantly lower in upper lobe tumors; higher interfraction amplitude variability indicated tumors in contact with mediastinal structures, although adhesion to parietal pleura did not necessarily reduce tumor motion amplitudes. The most variable lung tumors were metastatic lesions in women.« less

The CMB Topography Beneath Cook Inlet And Alaskan Kenai Peninsula

NASA Astrophysics Data System (ADS)

Wu, W.; Ni, S.

2009-05-01

It has long been known that the PcP-to-P amplitude ratios demonstrate strong scatter in some regions. Rost and Revenaugh studied PcP amplitudes which sample the core-mantle boundary (CMB) beneath the Alaskan Kenai peninsula and the Cook inlet and found a ˜1° region on the CMB with very large PcP/P amplitude ratios. For some events, the ratios are several tens times larger than the theoretical ratios. After analyzing different possible mechanisms, they concluded the CMB topography is the major cause of the high amplitude ratios, but they did not give an quantitative topography model because of the lack of short period synthetic waveforms tools. We generate short period PcP synthetics using representation theorems and study the PcP phases theoretically for a core-mantle boundary (CMB) with single sinusoidal topography. After testing different combinations of the sinusoid wavelength L and amplitude H, we conclude that a dent in CMB with diameter of L=300km and height H=1˜2km best fits the observed data and can partly explain the high amplitude ratios. The PcP reflected from the CMB dip with L=300km and H=2km will be amplified by 2˜3 times which is smaller than the value the observed data needed. We primarily have three causes to determine L=300km and H=1˜2km. First, a dip with L=300km and H=1˜2km will focus the PcP significantly in a ˜1° region on the CMB which is consistent with the observed data. Certainly, the northern limit of the region is not clear, therefore more data are needed to constraint the northern limit and give a more reliable model. Second, there are not obvious travel time anomalies coupled with the high ratios in the observed PcP and our synthetic travel time anomalies are just about 0.4s too. Lastly, the strong similarities of P and PcP for some simple events excludes such large value of H. A dip with larger L and corresponding H surly produces stronger focusing effect, for example, a dip with L= 300km and H=3km will amplifies the PcP by 4˜5 times, but the waveform will be distorted seriously, contradictory to the similarity of P and PcP. So we speculate that the topography and other causes are combined to produce the high amplitude ratios together.

Perceptual centres in speech - an acoustic analysis

NASA Astrophysics Data System (ADS)

Scott, Sophie Kerttu

Perceptual centres, or P-centres, represent the perceptual moments of occurrence of acoustic signals - the 'beat' of a sound. P-centres underlie the perception and production of rhythm in perceptually regular speech sequences. P-centres have been modelled both in speech and non speech (music) domains. The three aims of this thesis were toatest out current P-centre models to determine which best accounted for the experimental data bto identify a candidate parameter to map P-centres onto (a local approach) as opposed to the previous global models which rely upon the whole signal to determine the P-centre the final aim was to develop a model of P-centre location which could be applied to speech and non speech signals. The first aim was investigated by a series of experiments in which a) speech from different speakers was investigated to determine whether different models could account for variation between speakers b) whether rendering the amplitude time plot of a speech signal affects the P-centre of the signal c) whether increasing the amplitude at the offset of a speech signal alters P-centres in the production and perception of speech. The second aim was carried out by a) manipulating the rise time of different speech signals to determine whether the P-centre was affected, and whether the type of speech sound ramped affected the P-centre shift b) manipulating the rise time and decay time of a synthetic vowel to determine whether the onset alteration was had more affect on P-centre than the offset manipulation c) and whether the duration of a vowel affected the P-centre, if other attributes (amplitude, spectral contents) were held constant. The third aim - modelling P-centres - was based on these results. The Frequency dependent Amplitude Increase Model of P-centre location (FAIM) was developed using a modelling protocol, the APU GammaTone Filterbank and the speech from different speakers. The P-centres of the stimuli corpus were highly predicted by attributes of the increase in amplitude within one output channel of the filterbank. When this was used to make predictions of the P-centres for all the stimuli used in the thesis, 85[percent] of the observed variance was accounted for. The FAIM approach combines aspects of previous, speech and non speech models (Gordon 1987, Marcus 1981, Vos and Rasch 1981). P-centre were thus modelled in a non speech specific, local manner.

Minus-Lens–Stimulated Accommodative Amplitude Decreases Sigmoidally with Age: A Study of Objectively Measured Accommodative Amplitudes from Age 3

PubMed Central

Anderson, Heather A.; Hentz, Gloria; Glasser, Adrian; Stuebing, Karla K.; Manny, Ruth E.

2009-01-01

Purpose Guidelines for predicting accommodative amplitude by age are often based on subjective push-up test data that overestimate the accommodative response. Studies in which objective measurements were used have defined expected amplitudes for adults, but expected amplitudes for children remain unknown. In this study, objective methods were used to measure accommodative amplitude in a wide age range of individuals, to define the relationship of amplitude and age from age 3. Methods Accommodative responses were measured in 140 subjects aged 3 to 40 years. Measurements were taken with the Grand Seiko autorefractor (RyuSyo Industrial Co., Ltd., Kagawa, Japan) as the subjects viewed a high-contrast target at 33 cm through minus lenses of increasing power until the responses showed no further increase in accommodation. Results The maximum accommodative amplitude of each subject was plotted by age, and a curvilinear function fit to the data: y = 7.33 − 0.0035(age − 3)2 (P < 0.001). Tangent analysis of the fit indicated that the accommodative amplitude remained relatively stable until age 20. Data from this study were then pooled with objective amplitudes from previous studies of adults up to age 70. A sigmoidal function was fit to the data: y = 7.083/(1 + e[0.2031(age-36.2)−0.6109]) (P < 0.001). The sigmoidal function indicated relatively stable amplitudes below age 20 years, a rapid linear decline between 20 and 50 years, and a taper to 0 beyond 50 years. Conclusions These data indicate that accommodative amplitude decreases in a curvilinear manner from 3 to 40 years. When combined with data from previous studies, a sigmoidal function describes the overall trend throughout life with the biggest decrease occurring between 20 and 50 years. PMID:18326693

Measurement of the spin of the {xi}(1530) resonance

DOE Office of Scientific and Technical Information (OSTI.GOV)

Aubert, B.; Bona, M.; Karyotakis, Y.

The properties of the {xi}(1530) resonance are investigated in the {lambda}{sub c}{sup +}{yields}{xi}{sup -}{pi}{sup +}K{sup +} decay process. The data sample was collected with the BABAR detector at the SLAC PEP-II asymmetric-energy e{sup +}e{sup -} collider operating at center-of-mass energies 10.58 and 10.54 GeV. The corresponding integrated luminosity is approximately 230 fb{sup -1}. The spin of the {xi}(1530) is established to be 3/2. The existence of an S-wave amplitude in the {xi}{sup -}{pi}{sup +} system is inferred, and its interference with the {xi}(1530){sup 0} amplitude provides the first clear demonstration of the Breit-Wigner phase motion expected for the {xi}(1530). Themore » P{sub 1}(cos{theta}{sub {xi}}{sub {sup -}}) Legendre polynomial moment indicates the presence of a significant S-wave amplitude for {xi}{sup -}{pi}{sup +} mass values above 1.6 GeV/c{sup 2}, and a dip in the mass distribution at approximately 1.7 GeV/c{sup 2} is interpreted as due to the coherent addition of a {xi}(1690){sup 0} contribution to this amplitude. This would imply J{sup P}=1/2{sup -} for the {xi}(1690). Attempts at fitting the {xi}(1530){sup 0} line shape yield unsatisfactory results, and this failure is attributed to interference effects associated with the amplitudes describing the K{sup +}{pi}{sup +} and/or {xi}{sup -}K{sup +} systems.« less

Measurement of the Spin of the $$\\Xi(1530)$$ Resonance

DOE Office of Scientific and Technical Information (OSTI.GOV)

Aubert, B.; Bona, M.; Karyotakis, Y.

The properties of the {Xi}(1530) resonance are investigated in the {Lambda}{sub c}{sup +} {yields} {Xi}{sup -}{pi}{sup +}K{sup +} decay process. The data sample was collected with the BABAR detector at the SLAC PEP-II asymmetric-energy e{sup +}e{sup -} collider operating at center of mass energies 10.58 and 10.54 GeV. The corresponding integrated luminosity is approximately 230 fb{sup -1}. The spin of the {Xi}(1530) is established to be 3/2. The existence of an S-wave amplitude in the {Xi}{sup -}{pi}{sup +} system is inferred, and its interference with the {Xi}(1530)0 amplitude provides the first clear demonstration of the Breit-Wigner phase motion expected formore » the {Xi}(1530). The P{sub 1}(cos {theta}{sub {Xi}{sup -}}) Legendre polynomial moment indicates the presence of a significant S-wave amplitude for {Xi}{sup -}{pi}{sup +} mass values above 1.6 GeV/c{sup 2}, and a dip in the mass distribution at approximately 1.7 GeV/c{sup 2} is interpreted as due to coherent addition of a {Xi}(1690){sup 0} contribution to this amplitude. This would imply J{sup P} = 1/2{sup -} for the {Xi}(1690). Attempts at fitting the {Xi}(1530){sup 0} lineshape yield unsatisfactory results, and this failure is attributed to interference effects associated with the amplitudes describing the K{sup +}{pi}{sup +} and/or {Xi}{sup -}K{sup +} systems.« less

Different Timing Features in Brain Processing of Core and Moral Disgust Pictures: An Event-Related Potentials Study

PubMed Central

Zhang, Youxue; Lou, Liandi; Ding, Daoqun

2015-01-01

Disgust, an emotion motivating withdrawal from offensive stimuli, protects us from the risk of biological pathogens and sociomoral violations. Homogeneity of its two types, namely, core and moral disgust has been under intensive debate. To examine the dynamic relationship between them, we recorded event-related potentials (ERPs) for core disgust, moral disgust and neutral pictures while participants performed a modified oddball task. ERP analysis revealed that N1 and P2 amplitudes were largest for the core disgust pictures, indicating automatic processing of the core disgust-evoking pictures. N2 amplitudes were higher for pictures evoking moral disgust relative to core disgust and neutral pictures, reflecting a violation of social norms. The core disgust pictures elicited larger P3 and late positive potential (LPP) amplitudes in comparison with the moral disgust pictures which, in turn, elicited larger P3 and LPP amplitudes when compared to the neutral pictures. Taken together, these findings indicated that core and moral disgust pictures elicited different neural activities at various stages of information processing, which provided supporting evidence for the heterogeneity of disgust. PMID:26011635

Different timing features in brain processing of core and moral disgust pictures: an event-related potentials study.

PubMed

Zhang, Xiangyi; Guo, Qi; Zhang, Youxue; Lou, Liandi; Ding, Daoqun

2015-01-01

Disgust, an emotion motivating withdrawal from offensive stimuli, protects us from the risk of biological pathogens and sociomoral violations. Homogeneity of its two types, namely, core and moral disgust has been under intensive debate. To examine the dynamic relationship between them, we recorded event-related potentials (ERPs) for core disgust, moral disgust and neutral pictures while participants performed a modified oddball task. ERP analysis revealed that N1 and P2 amplitudes were largest for the core disgust pictures, indicating automatic processing of the core disgust-evoking pictures. N2 amplitudes were higher for pictures evoking moral disgust relative to core disgust and neutral pictures, reflecting a violation of social norms. The core disgust pictures elicited larger P3 and late positive potential (LPP) amplitudes in comparison with the moral disgust pictures which, in turn, elicited larger P3 and LPP amplitudes when compared to the neutral pictures. Taken together, these findings indicated that core and moral disgust pictures elicited different neural activities at various stages of information processing, which provided supporting evidence for the heterogeneity of disgust.

The music of language: an ERP investigation of the effects of musical training on emotional prosody processing.

PubMed

Pinheiro, Ana P; Vasconcelos, Margarida; Dias, Marcelo; Arrais, Nuno; Gonçalves, Óscar F

2015-01-01

Recent studies have demonstrated the positive effects of musical training on the perception of vocally expressed emotion. This study investigated the effects of musical training on event-related potential (ERP) correlates of emotional prosody processing. Fourteen musicians and fourteen control subjects listened to 228 sentences with neutral semantic content, differing in prosody (one third with neutral, one third with happy and one third with angry intonation), with intelligible semantic content (semantic content condition--SCC) and unintelligible semantic content (pure prosody condition--PPC). Reduced P50 amplitude was found in musicians. A difference between SCC and PPC conditions was found in P50 and N100 amplitude in non-musicians only, and in P200 amplitude in musicians only. Furthermore, musicians were more accurate in recognizing angry prosody in PPC sentences. These findings suggest that auditory expertise characterizing extensive musical training may impact different stages of vocal emotional processing. Copyright © 2014 Elsevier Inc. All rights reserved.

Isoflurane and ketamine:xylazine differentially affect intraocular pressure-associated scotopic threshold responses in Sprague-Dawley rats.

PubMed

Choh, Vivian; Gurdita, Akshay; Tan, Bingyao; Feng, Yunwei; Bizheva, Kostadinka; McCulloch, Daphne L; Joos, Karen M

2017-10-01

Amplitudes of electroretinograms (ERG) are enhanced during acute, moderate elevation of intraocular pressure (IOP) in rats anaesthetised with isoflurane. As anaesthetics alone are known to affect ERG amplitudes, the present study compares the effects of inhalant isoflurane and injected ketamine:xylazine on the scotopic threshold response (STR) in rats with moderate IOP elevation. Isoflurane-anaesthetised (n = 9) and ketamine:xylazine-anaesthetised (n = 6) rats underwent acute unilateral IOP elevation using a vascular loop anterior to the equator of the right eye. STRs to a luminance series (subthreshold to -3.04 log scotopic cd s/m 2 ) were recorded from each eye of Sprague-Dawley rats before, during, and after IOP elevation. Positive STR (pSTR) amplitudes for all conditions were significantly smaller (p = 0.0001) for isoflurane- than for ketamine:xylazine-anaesthetised rats. In addition, ketamine:xylazine was associated with a progressive increase in pSTR amplitudes over time (p = 0.0028). IOP elevation was associated with an increase in pSTR amplitude (both anaesthetics p < 0.0001). The absolute interocular differences in IOP-associated enhancement of pSTR amplitudes for ketamine:xylazine and isoflurane were similar (66.3 ± 35.5 vs. 54.2 ± 24.1 µV, respectively). However, the fold increase in amplitude during IOP elevation was significantly higher in the isoflurane- than in the ketamine:xylazine-anaesthetised rats (16.8 ± 29.7x vs. 2.1 ± 2.7x, respectively, p = 0.0004). The anaesthetics differentially affect the STRs in the rat model with markedly reduced amplitudes with isoflurane compared to ketamine:xylazine. However, the IOP-associated enhancement is of similar absolute magnitude for the two anaesthetics, suggesting that IOP stress and anaesthetic effects operate on separate retinal mechanisms.

Calcium-dependent nonspecific permeability of the inner mitochondrial membrane is not induced in mitochondria of the yeast Endomyces magnusii.

PubMed

Deryabina, Y I; Isakova, E P; Shurubor, E I; Zvyagilskaya, R A

2004-09-01

Mitochondria of the yeast Endomyces magnusii were examined for the presence of a Ca2+- and phosphate-induced permeability of the inner mitochondrial membrane (pore). For this purpose, coupled mitochondria were incubated under conditions known to induce the permeability transition pore in animal mitochondria, i.e., in the presence of high concentrations of Ca2+ and P(i), prooxidants (t-butylhydroperoxide), oxaloacetate, atractyloside (an inhibitor of ADP/ATP translocator), SH-reagents, by depletion of adenine nucleotide pools, and deenergization of the mitochondria. Large amplitude swelling, collapse of the membrane potential, and efflux of the accumulated Ca2+ were used as parameters for demonstrating pore induction. E. magnusii mitochondria were highly resistant to the above-mentioned substances. Deenergization of mitochondria or depletion of adenine nucleotide pools have no effect on low-amplitude swelling or the other parameters. Cyclosporin A, a specific inhibitor of the nonspecific permeability transition in animal mitochondria, did not affect the parameters measured. It is thus evident that E. magnusii mitochondria lack a functional Ca2+-dependent pore, or possess a pore differently regulated as compared to that of mammalian mitochondria.

Gate line edge roughness amplitude and frequency variation effects on intra die MOS device characteristics

NASA Astrophysics Data System (ADS)

Hamadeh, Emad; Gunther, Norman G.; Niemann, Darrell; Rahman, Mahmud

2006-06-01

Random fluctuations in fabrication process outcomes such as gate line edge roughness (LER) give rise to corresponding fluctuations in scaled down MOS device characteristics. A thermodynamic-variational model is presented to study the effects of LER on threshold voltage and capacitance of sub-50 nm MOS devices. Conceptually, we treat the geometric definition of the MOS devices on a die as consisting of a collection of gates. In turn, each of these gates has an area, A, and a perimeter, P, defined by nominally straight lines subject to random process outcomes producing roughness. We treat roughness as being deviations from straightness consisting of both transverse amplitude and longitudinal wavelength each having lognormal distribution. We obtain closed-form expressions for variance of threshold voltage ( Vth), and device capacitance ( C) at Onset of Strong Inversion (OSI) for a small device. Using our variational model, we characterized the device electrical properties such as σ and σC in terms of the statistical parameters of the roughness amplitude and spatial frequency, i.e., inverse roughness wavelength. We then verified our model with numerical analysis of Vth roll-off for small devices and σ due to dopant fluctuation. Our model was also benchmarked against TCAD of σ as a function of LER. We then extended our analysis to predict variations in σ and σC versus average LER spatial frequency and amplitude, and oxide-thickness. Given the intuitive expectation that LER of very short wavelengths must also have small amplitude, we have investigated the case in which the amplitude mean is inversely related to the frequency mean. We compare with the situation in which amplitude and frequency mean are unrelated. Given also that the gate perimeter may consist of different LER signature for each side, we have extended our analysis to the case when the LER statistical difference between gate sides is moderate, as well as when it is significantly large.

Validating the use of scintillation proxies to study ionospheric scintillation over the Ugandan region

NASA Astrophysics Data System (ADS)

Amabayo, Emirant B.; Jurua, Edward; Cilliers, Pierre J.

2015-06-01

In this study, we compare the standard scintillation indices (S4 and σΦ) from a SCINDA receiver with scintillation proxies (S4p and | sDPR |) derived from two IGS GPS receivers. Amplitude (S4) and phase (σΦ) scintillation data were obtained from the SCINDA installed at Makerere University (0.34°N, 32.57°E). The corresponding amplitude (S4p) and phase (| sDPR |) scintillation proxies were derived from data archived by IGS GPS receivers installed at Entebbe (0.04°N, 32.44°E) and Mbarara (0.60°S, 30.74°E). The results show that for most of the cases analysed in this study, σΦ and | sDPR | are in agreement. Amplitude scintillation occurrence estimated using the S4p are fairly consistent with the standard S4, mainly between 17:00 UT and 21:00 UT, despite a few cases of over and under estimation of scintillation levels by S4p. Correlation coefficients between σΦ and the | sDPR | proxy revealed positive correlation. Generally, S4p and S4 exhibits both moderate and strong positive correlation. TEC depletions associated with equatorial plasma bubbles are proposed as the cause of the observed scintillation over the region. These equatorial plasma bubbles were evident along the ray paths to satellites with PRN 2, 15, 27 and 11 as observed from MBAR and EBBE. In addition to equatorial plasma bubbles, atmospheric gravity waves with periods similar to those of large scale traveling ionospheric disturbances were also observed as one of the mechanisms for scintillation occurrence. The outcome of this study implies that GPS derived scintillation proxies can be used to quantify scintillation levels in the absence of standard scintillation data in the equatorial regions.

The effects of familiarity and emotional expression on face processing examined by ERPs in patients with schizophrenia.

PubMed

Caharel, Stéphanie; Bernard, Christian; Thibaut, Florence; Haouzir, Sadec; Di Maggio-Clozel, Carole; Allio, Gabrielle; Fouldrin, Gaël; Petit, Michel; Lalonde, Robert; Rebaï, Mohamed

2007-09-01

The main objective of the study was to determine whether patients with schizophrenia are deficient relative to controls in the processing of faces at different levels of familiarity and types of emotion and the stage where such differences may occur. ERPs based on 18 patients with schizophrenia and 18 controls were compared in a face identification task at three levels of familiarity (unknown, familiar, subject's own) and for three types of emotion (disgust, smiling, neutral). The schizophrenic group was less accurate than controls in the face processing, especially for unknown faces and those expressing negative emotions such as disgust. P1 and N170 amplitudes were lower and P1, N170, P250 amplitudes were of slower onset in patients with schizophrenia. N170 and P250 amplitudes were modulated by familiarity and face expression in a different manner in patients than controls. Schizophrenia is associated with a genelarized defect of face processing, both in terms of familiarity and emotional expression, attributable to deficient processing at sensory (P1) and perceptual (N170) stages. These patients appear to have difficulty in encoding the structure of a face and thereby do not evaluate correctly familiarity and emotion.

Neonate Auditory Brainstem Responses to CE-Chirp and CE-Chirp Octave Band Stimuli II: Versus Adult Auditory Brainstem Responses.

PubMed

Cobb, Kensi M; Stuart, Andrew

The purpose of the study was to examine the differences in auditory brainstem response (ABR) latency and amplitude indices to the CE-Chirp stimuli in neonates versus young adults as a function of stimulus level, rate, polarity, frequency and gender. Participants were 168 healthy neonates and 20 normal-hearing young adults. ABRs were obtained to air- and bone-conducted CE-Chirps and air-conducted CE-Chirp octave band stimuli. The effects of stimulus level, rate, and polarity were examined with air-conducted CE-Chirps. The effect of stimulus level was also examined with bone-conducted CE-Chirps and CE-Chirp octave band stimuli. The effect of gender was examined across all stimulus manipulations. In general, ABR wave V amplitudes were significantly larger (p < 0.0001) and latencies were significantly shorter (p < 0.0001) for adults versus neonates for all air-conducted CE-Chirp stimuli with all stimulus manipulations. For bone-conducted CE-Chirps, infants had significantly shorter wave V latencies than adults at 15 dB nHL and 45 dB nHL (p = 0.02). Adult wave V amplitude was significantly larger for bone-conducted CE-Chirps only at 30 dB nHL (p = 0.02). The effect of gender was not statistically significant across all measures (p > 0.05). Significant differences in ABR latencies and amplitudes exist between newborns and young adults using CE-Chirp stimuli. These differences are consistent with differences to traditional click and tone burst stimuli and reflect maturational differences as a function of age. These findings continue to emphasize the importance of interpreting ABR results using age-based normative data.

Changes in P3b Latency and Amplitude Reflect Expertise Acquisition in a Football Visuomotor Learning Task.

PubMed

Morgan, Kyle K; Luu, Phan; Tucker, Don M

2016-01-01

Learning is not a unitary phenomenon. Rather, learning progresses through stages, with the stages reflecting different challenges that require the support of specific cognitive processes that reflect the functions of different brain networks. A theory of general learning proposes that learning can be divided into early and late stages controlled by corticolimbic networks located in frontal and posterior brain regions, respectively. Recent human studies using dense-array EEG (dEEG) support these results by showing progressive increases in P3b amplitude (an Event Related Potential with estimated sources in posterior cingulate cortex and hippocampus) as participants acquire a new visuomotor skill. In the present study, the P3b was used to track the learning and performance of participants as they identify defensive football formations and make an appropriate response. Participants acquired the task over three days, and P3b latency and amplitude significantly changed when participants learned the task. As participants demonstrated further proficiency with extensive training, amplitude and latency changes in the P3b continued to closely mirror performance improvements. Source localization results across all days suggest that an important source generator of the P3b is located in the posterior cingulate cortex. Results from the study support prior findings and further suggest that the careful analysis of covert learning mechanisms and their underlying electrical signatures are a robust index of task competency.

Neural correlates of performance monitoring in chronic cannabis users and cannabis-naïve controls

PubMed Central

Fridberg, Daniel J; Skosnik, Patrick D; Hetrick, William P; O’Donnell, Brian F

2014-01-01

Chronic cannabis use is associated with residual negative effects on measures of executive functioning. However, little previous work has focused specifically on executive processes involved in performance monitoring in frequent cannabis users. The present study investigated event-related potential (ERP) correlates of performance monitoring in chronic cannabis users. The error-related negativity (ERN) and error positivity (Pe), ERPs sensitive to performance monitoring, were recorded from 30 frequent cannabis users (mean usage=5.52 days/week) and 32 cannabis-naïve control participants during a speeded stimulus discrimination task. The “oddball” P3 ERP was recorded as well. Users and controls did not differ on the amplitude or latency of the ERN; however, Pe amplitude was larger among users. Users also showed increased amplitude and reduced latency of the P3 in response to infrequent stimuli presented during the task. Among users, urinary cannabinoid metabolite levels at testing were unrelated to ERP outcomes. However, total years of cannabis use correlated negatively with P3 latency and positively with P3 amplitude, and age of first cannabis use correlated negatively with P3 amplitude. The results of this study suggest that chronic cannabis use is associated with alterations in neural activity related to the processing of motivationally-relevant stimuli (P3) and errors (Pe). PMID:23427191

The effect of elevations in internal temperature on event-related potentials during a simple cognitive task in humans.

PubMed

Shibasaki, Manabu; Namba, Mari; Oshiro, Misaki; Crandall, Craig G; Nakata, Hiroki

2016-07-01

The effect of hyperthermia on cognitive function remains equivocal, perhaps because of methodological discrepancy. Using electroencephalographic event-related potentials (ERPs), we tested the hypothesis that a passive heat stress impairs cognitive processing. Thirteen volunteers performed repeated auditory oddball paradigms under two thermal conditions, normothermic time control and heat stress, on different days. For the heat stress trial, these paradigms were performed at preheat stress (i.e., normothermic) baseline, when esophageal temperature had increased by ∼0.8°C, when esophageal temperature had increased by ∼2.0°C, and during cooling following the heat stress. The reaction time and ERPs were recorded in each session. For the time control trial, subjects performed the auditory oddball paradigms at approximately the same time interval as they did in the heat stress trial. The peak latency and amplitude of an indicator of auditory processing (N100) were not altered regardless of thermal conditions. An indicator of stimulus classification/evaluation time (latency of P300) and the reaction time were shortened during heat stress; moreover an indicator of cognitive processing (the amplitude of P300) was significantly reduced during severe heat stress (8.3 ± 1.3 μV) relative to the baseline (12.2 ± 1.0 μV, P < 0.01). No changes in these indexes occurred during the time control trial. During subsequent whole body cooling, the amplitude of P300 remained reduced, and the reaction time and latency of P300 remained shortened. These results suggest that excessive elevations in internal temperature reduce cognitive processing but promote classification time. Copyright © 2016 the American Physiological Society.

Multiscale Problems in Circadian Systems Biology: From Gene to Cell to Performance

DTIC Science & Technology

2012-03-22

observed circadian phenotypes of gene knockouts including circadian amplitude variation due to loss of metabolic activity (e.g. SIRT1 -/-), Figure 9(right...non peer-reviewed journals: 1. Foteinou P.T., J. Hogenesch and F.J. Doyle 3rd. Elucidating the Effects of SIRT1 on Circadian Amplitude: Insights from...central pacemaker in the suprachiasmatic nucleus (SCN) which coordinates the oscillating activity of peripheral clocks that are present in almost all

Experience-dependent increase in spine calcium evoked by backpropagating action potentials in layer 2/3 pyramidal neurons in rat somatosensory cortex.

PubMed

Krieger, Patrik

2009-11-01

In spines on basal dendrites of layer 2/3 pyramidal neurons in somatosensory barrel cortex, calcium transients evoked by back-propagating action potentials (bAPs) were investigated (i) along the length of the basal dendrite, (ii) with postnatal development and (iii) with sensory deprivation during postnatal development. Layer 2/3 pyramidal neurons were investigated at three different ages. At all ages [postnatal day (P)8, P14, P21] the bAP-evoked calcium transient amplitude increased with distance from the soma with a peak at around 50 microm, followed by a gradual decline in amplitude. The effect of sensory deprivation on the bAP-evoked calcium was investigated using two different protocols. When all whiskers on one side of the rat snout were trimmed daily from P8 to P20-24 there was no difference in the bAP-evoked calcium transient between cells in the contralateral hemisphere, lacking sensory input from the whisker, and cells in the ipsilateral barrel cortex, with intact whisker activation. When, however, only the D-row whiskers on one side were trimmed the distribution of bAP-evoked calcium transients in spines was shifted towards larger amplitudes in cells located in the deprived D-column. In conclusion, (i) the bAP-evoked calcium transient gradient along the dendrite length is established at P8, (ii) the calcium transient increases in amplitude with age and (iii) this increase is enhanced in layer 2/3 pyramidal neurons located in a sensory-deprived barrel column that is bordered by non-deprived barrel columns.

An ERP study of agreement features in Spanish.

PubMed

Silva-Pereyra, Juan F; Carreiras, Manuel

2007-12-14

The goal of the present study was to investigate whether two morphological agreement features, Person and Number, play a different role in the agreement process. According to the Feature Hierarchy hypothesis, different nominal agreement features have different degrees of cognitive strength (e.g., Person>Number). Event-related potentials (ERPs) were collected from Spanish speakers while they read sentences in which either Person Disagreement (PD; e.g., Tú salto en el patio [You (2ndPerSing) jump (1stPerSing) in the backyard]), Number Disagreement (ND; e.g., Nosotros salto en el patio [We (1stPerPl) jump (1stPerSing) in the backyard]) or both Person and Number Disagreement (NPD; e.g., Ustedes salto en el patio [You (2ndPerPl) jump (1stPerSing) in the backyard]) relationships were manipulated. ND, PD and NPD all elicited an anterior negativity (AN) and P600 pattern. An AN effect was only found in the NPD with a different topography from the classic LAN effect as it was lateralized to right and central sites. The P600 effect elicited by the NPD condition was larger than the agreement condition and that of ND and PD in the first window 500-700, while the three disagreement conditions elicited larger P600 amplitudes than the agreement condition in the second window 700-900. There were no differences between the processing of person and number. Thus, the combination of number and person disagreement could be solved in parallel through an additive mechanism of the two features. These results do not support the Feature Hierarchy hypothesis.

P3 event-related potentials and childhood maltreatment in successful and unsuccessful psychopaths

PubMed Central

Gao, Yu; Raine, Adrian; Schug, Robert A.

2011-01-01

Although P3 event-related potential abnormalities have been found in psychopathic individuals, it is unknown whether successful (uncaught) psychopaths and unsuccessful (caught) psychopaths show similar deficits. In this study, P3 amplitude and latency were assessed from a community sample of 121 male adults using an auditory three-stimulus oddball task. Psychopathy was assessed using the Psychopathy Checklist-Revised (Hare, 2003) while childhood physical maltreatment was assessed using the Conflict Tactic Scale (Strauss, 1979). Results revealed that compared to normal controls, unsuccessful psychopaths showed reduced parietal P3 amplitudes to target stimuli and reported experienced more physical abuse in childhood. In contrast, successful psychopaths exhibited larger parietal P3 amplitude and shorter frontal P3 latency to irrelevant nontarget stimuli than unsuccessful psychopaths. This is the first report of electrophysiological processing differences between successful and unsuccessful psychopaths, possibly indicating neurocognitive and psychosocial distinctions between these two subtypes of psychopathy. PMID:21820788

Informational Masking Effects on Neural Encoding of Stimulus Onset and Acoustic Change.

PubMed

Niemczak, Christopher E; Vander Werff, Kathy R

2018-05-18

Recent investigations using cortical auditory evoked potentials have shown masker-dependent effects on sensory cortical processing of speech information. Background noise maskers consisting of other people talking are particularly difficult for speech recognition. Behavioral studies have related this to perceptual masking, or informational masking, beyond just the overlap of the masker and target at the auditory periphery. The aim of the present study was to use cortical auditory evoked potentials, to examine how maskers (i.e., continuous speech-shaped noise [SSN] and multi-talker babble) affect the cortical sensory encoding of speech information at an obligatory level of processing. Specifically, cortical responses to vowel onset and formant change were recorded under different background noise conditions presumed to represent varying amounts of energetic or informational masking. The hypothesis was, that even at this obligatory cortical level of sensory processing, we would observe larger effects on the amplitude and latency of the onset and change components as the amount of informational masking increased across background noise conditions. Onset and change responses were recorded to a vowel change from /u-i/ in young adults under four conditions: quiet, continuous SSN, eight-talker (8T) babble, and two-talker (2T) babble. Repeated measures analyses by noise condition were conducted on amplitude, latency, and response area measurements to determine the differential effects of these noise conditions, designed to represent increasing and varying levels of informational and energetic masking, on cortical neural representation of a vowel onset and acoustic change response waveforms. All noise conditions significantly reduced onset N1 and P2 amplitudes, onset N1-P2 peak to peak amplitudes, as well as both onset and change response area compared with quiet conditions. Further, all amplitude and area measures were significantly reduced for the two babble conditions compared with continuous SSN. However, there were no significant differences in peak amplitude or area for either onset or change responses between the two different babble conditions (eight versus two talkers). Mean latencies for all onset peaks were delayed for noise conditions compared with quiet. However, in contrast to the amplitude and area results, differences in peak latency between SSN and the babble conditions did not reach statistical significance. These results support the idea that while background noise maskers generally reduce amplitude and increase latency of speech-sound evoked cortical responses, the type of masking has a significant influence. Speech babble maskers (eight talkers and two talkers) have a larger effect on the obligatory cortical response to speech sound onset and change compared with purely energetic continuous SSN maskers, which may be attributed to informational masking effects. Neither the neural responses to the onset nor the vowel change, however, were sensitive to the hypothesized increase in the amount of informational masking between speech babble maskers with two talkers compared with eight talkers.

Comparisons of planetary wave propagation to the upper atmosphere during stratospheric warming events at different QBO phases

NASA Astrophysics Data System (ADS)

Koval, Andrey V.; Gavrilov, Nikolai M.; Pogoreltsev, Alexander I.; Savenkova, Elena N.

2018-06-01

The dynamical coupling of the lower and upper atmosphere by planetary waves (PWs) is studied. Numerical simulations of planetary wave (PW) amplitudes during composite sudden stratospheric warming (SSW) events in January-February are made using a model of general circulation of the middle and upper atmosphere with initial and boundary conditions typical for the westerly and easterly phases of quasi-biennial oscillation (QBO). The changes in PW amplitudes in the middle atmosphere before, during and after SSW event for the different QBO phases are considered. Near the North Pole, the increase in the mean temperature during SSW reaches 10-30 K at altitudes 30-50 km for four pairs of the model runs with the eQBO and wQBO, which is characteristic for the sudden stratospheric warming event. Amplitudes of stationary PWs in the middle atmosphere of the Northern hemisphere may differ up to 30% during wQBO and eQBO before and during the SSW. After the SSW event SPW amplitudes are substantially larger during wQBO phase. PW refractivity indices and Eliassen-Palm flux vectors are calculated. The largest EP-fluxes in the middle atmosphere correspond to PWs with zonal wavenumber m=1. Simulated changes in PW amplitudes correspond to inhomogeneities of the global circulation, refractivity index and EP-flux produced by the changes in QBO phases. Comparisons of differences in PW characteristics and circulation between the wQBO and eQBO show that PWs could provide effective coupling mechanism and transport dynamical changes from local regions of the lower atmosphere to distant regions of the upper atmosphere of both hemispheres.

Does the Dumbbell-Carrying Position Change the Muscle Activity in Split Squats and Walking Lunges?

PubMed Central

Lehnert, Michal; Zaatar, Amr M.Z.; Svoboda, Zdenek; Xaverova, Zuzana

2015-01-01

Abstract Stastny, P, Lehnert, M, Zaatar, AMZ, Svoboda, Z, and Xaverova, Z. Does the dumbbell-carrying position change the muscle activity in split squats and walking lunges? J Strength Cond Res 29(11): 3177–3187, 2015—The forward walking lunge (WL) and split squat (SSq) are similar exercises that have differences in the eccentric phase, and both can be performed in the ipsilateral or contralateral carrying conditions. This study aimed to determine the effects of dumbbell-carrying position on the kinematics and electromyographic (EMG) amplitudes of the gluteus medius (Gmed), vastus medialis (VM), vastus lateralis (VL), and biceps femoris during WLs and SSqs. The resistance-trained (RT) and the non–resistance-trained (NT) groups (both n = 14) performed ipsilateral WLs, contralateral WLs, ipsilateral SSqs, and contralateral SSqs in a randomized order in a simulated training session. The EMG amplitude, expressed as a percentage of the maximal voluntary isometric contraction (%MVIC), and the kinematics, expressed as the range of motion (ROM) of the hip and knee, were measured during 5 repetition maximum for both legs. The repeated measure analyses of variance showed significant differences between the RT and NT groups. The NT group showed a smaller knee flexion ROM (p < 0.001, η2 = 0.36) during both types of WLs, whereas the RT group showed a higher eccentric Gmed amplitude (p < 0.001, η2 = 0.46) during all exercises and a higher eccentric VL amplitude (p < 0.001, η2 = 0.63) during contralateral WLs. Further differences were found between contralateral and ipsilateral WLs in both the RT (p < 0.001, η2 = 0.69) and NT groups (p < 0.001, η2 = 0.80), and contralateral WLs resulted in higher eccentric Gmed amplitudes. Contralateral WLs highly activated the Gmed (90% MVIC); therefore, this exercise can increase the Gmed maximal strength. The ipsilateral loading condition did not increase the Gmed or VM activity in the RT or NT group. PMID:25968228

P300 component of event-related potentials in persons with asperger disorder.

PubMed

Iwanami, Akira; Okajima, Yuka; Ota, Haruhisa; Tani, Masayuki; Yamada, Takashi; Yamagata, Bun; Hashimoto, Ryuichiro; Kanai, Chieko; Takashio, Osamu; Inamoto, Atsuko; Ono, Taisei; Takayama, Yukiko; Kato, Nobumasa

2014-10-01

In the present study, we investigated auditory event-related potentials in adults with Asperger disorder and normal controls using an auditory oddball task and a novelty oddball task. Task performance and the latencies of P300 evoked by both target and novel stimuli in the two tasks did not differ between the two groups. Analysis of variance revealed that there was a significant interaction effect between group and electrode site on the mean amplitude of the P300 evoked by novel stimuli, which indicated that there was an altered distribution of the P300 in persons with Asperger disorder. In contrast, there was no significant interaction effect on the mean P300 amplitude elicited by target stimuli. Considering that P300 comprises two main subcomponents, frontal-central-dominant P3a and parietal-dominant P3b, our results suggested that persons with Asperger disorder have enhanced amplitude of P3a, which indicated activated prefrontal function in this task.

Relativistic proton-nucleus scattering and one-boson-exchange models

NASA Technical Reports Server (NTRS)

Maung, Khin Maung; Gross, Franz; Tjon, J. A.; Townsend, L. W.; Wallace, S. J.

1993-01-01

Relativistic p-(Ca-40) elastic scattering observables are calculated using four sets of relativistic NN amplitudes obtained from different one-boson-exchange (OBE) models. The first two sets are based upon a relativistic equation in which one particle is on mass shell and the other two sets are obtained from a quasipotential reduction of the Bethe-Salpeter equation. Results at 200, 300, and 500 MeV are presented for these amplitudes. Differences between the predictions of these models provide a study of the uncertainty in constructing Dirac optical potentials from OBE-based NN amplitudes.

Sex differences in event-related potentials and attentional biases to emotional facial stimuli.

PubMed

Pfabigan, Daniela M; Lamplmayr-Kragl, Elisabeth; Pintzinger, Nina M; Sailer, Uta; Tran, Ulrich S

2014-01-01

Attentional processes play an important role in the processing of emotional information. Previous research reported attentional biases during stimulus processing in anxiety and depression. However, sex differences in the processing of emotional stimuli and higher prevalence rates of anxiety disorders among women, compared to men, suggest that attentional biases may also differ between the two sexes. The present study used a modified version of the dot probe task with happy, angry, and neutral facial stimuli to investigate the time course of attentional biases in healthy volunteers. Moreover, associations of attentional biases with alexithymia were examined on the behavioral and physiological level. Event-related potentials were measured while 21 participants (11 women) performed the task, utilizing also for the first time a difference wave approach in the analysis to highlight emotion-specific aspects. Women showed overall enhanced probe P1 amplitudes compared to men, in particular after rewarding facial stimuli. Using the difference wave approach, probe P1 amplitudes appeared specifically enhanced with regard to congruently presented happy facial stimuli among women, compared to men. Both methods yielded enhanced probe P1 amplitudes after presentation of the emotional stimulus in the left compared to the right visual hemifield. Probe P1 amplitudes correlated negatively with self-reported alexithymia, most of these correlations were only observable in women. Our results suggest that women orient their attention to a greater extent to facial stimuli than men and corroborate that alexithymia is a correlate of reduced emotional reactivity on a neuronal level. We recommend using a difference wave approach when addressing attentional processes of orientation and disengagement also in future studies.

Nonlinear excitations for the positron acoustic shock waves in dissipative nonextensive electron-positron-ion plasmas

NASA Astrophysics Data System (ADS)

Saha, Asit

2017-03-01

Positron acoustic shock waves (PASHWs) in unmagnetized electron-positron-ion (e-p-i) plasmas consisting of mobile cold positrons, immobile positive ions, q-nonextensive distributed electrons, and hot positrons are studied. The cold positron kinematic viscosity is considered and the reductive perturbation technique is used to derive the Burgers equation. Applying traveling wave transformation, the Burgers equation is transformed to a one dimensional dynamical system. All possible vector fields corresponding to the dynamical system are presented. We have analyzed the dynamical system with the help of potential energy, which helps to identify the stability and instability of the equilibrium points. It is found that the viscous force acting on cold mobile positron fluid is a source of dissipation and is responsible for the formation of the PASHWs. Furthermore, fully nonlinear arbitrary amplitude positron acoustic waves are also studied applying the theory of planar dynamical systems. It is also observed that the fundamental features of the small amplitude and arbitrary amplitude PASHWs are significantly affected by the effect of the physical parameters q e , q h , μ e , μ h , σ , η , and U. This work can be useful to understand the qualitative changes in the dynamics of nonlinear small amplitude and fully nonlinear arbitrary amplitude PASHWs in solar wind, ionosphere, lower part of magnetosphere, and auroral acceleration regions.

P300: Waves Identification with and without Subtraction of Traces

PubMed Central

Romero, Ana Carla Leite; Reis, Ana Cláudia Mirândola Barbosa; Oliveira, Anna Caroline Silva de; Oliveira Simões, Humberto de; Oliveira Junqueira, Cinthia Amorim de; Frizzo, Ana Cláudia Figueiredo

2017-01-01

Introduction  The P300 test requires well-defined and unique criteria, in addition to training for the examiners, for a uniform analysis of studies and to avoid variations and errors in the interpretation of measurement results. Objectives  The objective of this study is to verify whether there are differences in P300 with and without subtraction of traces of standard and nonstandard stimuli. Method  We conducted this study in collaboration with two research electrophysiology laboratories. From Laboratory 1, we selected 40 tests of subjects between 7–44 years, from Laboratory 2, we selected 83 tests of subjects between 18–44 years. We first performed the identification with the nonstandard stimuli; then, we subtracted the nonstandard stimuli from the standard stimuli. The examiners identified the waves, performing a descriptive and comparative analysis of traces with and without subtraction. Results  After a comparative analysis of the traces with and without subtraction, there was no significant difference when compared with analysis of traces in both laboratories, within the conditions, of right ears ( p  = 0.13 and 0.28 for differences between latency and amplitude measurements) and left ears ( p  = 0.15 and 0.09 for differences between latency and amplitude measurements) from Laboratory 1. As for Laboratory 2, when investigating both ears, results did not identify significant differences ( p  = 0.098 and 0.28 for differences between latency and amplitude measurements). Conclusion  There was no difference verified in traces with and without subtraction. We suggest the identification of this potential performed through nonstandard stimuli. PMID:29018497

Search for Quadrupole Strength in the Electroexcitation of the Delta+ (1232)

DOE Office of Scientific and Technical Information (OSTI.GOV)

C. Mertz; C. Vellidis; Ricardo Alarcon

2001-04-01

High precision 1H(e, e'p)pi0 measurements at Q2 = 0.126. (GeV/c)2 are reported, which allow the determination of quadrupole amplitudes in the gamma*N --> Delta transition; they simultaneously test the reliability of electroproduction models. The derived quadrupole-to-dipole (I = 3/2) amplitude ratios, RSM = (-6.5 +/- 0.2stat+sys+/-2.5mod)% and REM = 9-2.1 +/-0.2stat+sys +/-2.0mod)%, are dominated by model error. Previous RSM and REM results should be reconsidered after the model uncertainties associated with the method of their extraction are taken into account.

Analysis of variance study of the rat cortical layer 4 barrel and layer 5b neurones

PubMed Central

Ito, Muneyuki; Kato, Miyuki

2002-01-01

Unique formation of rodent cortical barrels by layer 4 neurones attracts study of the sensory function of cortical input stage neurones (layer 4) compared with that of output stage neurones (layer 5). We have recorded extracellular responses from rat somatosensory cortical neurones to deflections of contralateral vibrissae. Thirty-two layer 4 barrel neurones and 29 layer 5b neurones were studied. Whisker stimulations were ramp-and-hold deflections with one of six different ramp velocities (100–2.5 mm s−1) and one of four different plateau amplitudes (2000–200 μm). Twenty-four (6 × 4) different stimulus forms were applied to the tip of a whisker trimmed to 10 mm in a predetermined order in stimulus cycles of 20–50 repetitions. Spike counts for a period of 2560 ms in 10 ms bins were summed to construct a matrix of 24 peristimulus histograms for each neurone. Twenty-four amplitude and 24 velocity values were computed from counts during the plateau and ramp phases, respectively. To determine the amplitude- and velocity dependence of a neurone, an amplitude F value (the ratio of variations among-/within-amplitude of the amplitude value) and a velocity F value (ratio of variations among-/within-velocity of the velocity value) were derived by analysis of variance. The amplitude F value of the layer 4 barrel neurones was greater than that of the layer 5b neurones (P < 0.0001). The velocity F value of the barrel neurones was smaller than that of the layer 5b neurones (P = 0.0226). The results suggests that barrel neurones and layer 5b neurones tend to detect amplitude and velocity components of whisker deflection, respectively. PMID:11882683

Antennal olfactory responses of adult meadow spittlebug, Philaenus spumarius, to volatile organic compounds (VOCs)

PubMed Central

Ganassi, Sonia; Pistillo, Marco O.; Di Domenico, Carmela; De Cristofaro, Antonio; Di Palma, Antonella Marta

2017-01-01

The meadow spittlebug, Philaenus spumarius L. (Hemiptera, Aphrophoridae) is a commonly found vector of Xylella fastidiosa Wells et al. (1987) strain subspecies pauca associated with the “Olive Quick Decline Syndrome” in Italy. To contribute to the knowledge of the adult P. spumarius chemoreceptivity, electroantennographic (EAG) responses of both sexes to 50 volatile organic compounds (VOCs) including aliphatic aldehydes, alcohols, esters, and ketones, terpenoids, and aromatics were recorded. Measurable EAG responses were elicited by all compounds tested. In both sexes, octanal, 2-octanol, 2-decanone, (E)-2-hexenyl acetate, and vanillin elicited the strongest antennal amplitude within the chemical groups of aliphatic saturated aldehydes, aliphatic alcohols, aliphatic acetates and aromatics, respectively. Male and female EAG responses to sulcatol, (±)linalool, and sulcatone were higher than those to other terpenoinds. In both sexes, the weakest antennal stimulants were phenethyl alcohol and 2-pentanone. Sexual differences in the EAG amplitude were found only for four of test compounds suggesting a general similarity between males and females in antennal sensitivity. The olfactory system of both sexes proved to be sensitive to changes in stimulus concentration, carbon chain length, and compound structure. Compounds with short carbon chain length (C5—C6) elicited lower EAG amplitudes than compounds with higher carbon chain length (C9—C10) in all classes of aliphatic hydrocarbons with different functional groups. The elucidation of the sensitivity profile of P. spumarius to a variety of VOCs provides a basis for future identification of behaviorally-active compounds useful for developing semiochemical-based control strategies of this pest. PMID:29287108

Re-emergent tremor in Parkinson's disease: Clinical and accelerometric properties.

PubMed

Aytürk, Zübeyde; Yilmaz, Rezzak; Akbostanci, M Cenk

2017-03-01

Re-emergent tremor (RET) and the classical parkinsonian rest tremor were considered as two different phenomena of the same central tremor circuit. However, clinical and accelerometric characteristics of these tremors were not previously compared in a single study. We evaluated disease characteristics and accelerometric measurements of two tremor types in 42 patients with Parkinson's disease. Disease specific features and accelerometric measurements of peak frequency, amplitude at peak frequency and the root mean square (RMS) amplitude of two tremor types were compared. Eighteen patients had RET and the mean latency of the RET was 9.48 (±9.2)s. Groups of only rest tremor and RET did not differ significantly in age of disease onset, disease duration and severity and mean levodopa equivalent dose. Comparison of peak frequency and amplitude at peak frequency were not different between the groups, but RMS amplitude was significantly higher in the RET group (p=0.03). RMS amplitude of RET was also correlated with disease severity (r=.48, p=0.04). These results support the previous notion that rest tremor and RET are analogue, both are triggered by the same central ossilator with RET being only the suppression of the rest tremor due to arm repositioning. Copyright © 2016 Elsevier Ltd. All rights reserved.

Lower P300 amplitude in eight-year-old offspring of alcoholic fathers with a delinquent history.

PubMed

Viana-Wackermann, Paula C; Furtado, Erikson F; Esser, Günter; Schmidt, Martin H; Laucht, Manfred

2007-06-01

The aim of the present study was to investigate the P300 amplitude as a possible vulnerability marker in children of alcoholic (COA) fathers with and without paternal delinquency. Event-related potentials (ERPs) of 122 children aged 8 years (63 boys, 59 girls) were compared depending on father's alcoholism subtype: 30 COAs without paternal delinquency, 10 COAs with paternal delinquency, and 82 children of non-alcoholic and non-delinquent fathers. ERPs were recorded from Fz, Cz, and Pz, using an auditory oddball paradigm. Sinus tones of 60 dB HL were presented binaurally at 1,000 Hz (standard stimulus) and 2,000 Hz (target stimulus), at a relative frequency ratio of 80:20. Two trial blocks of 250 stimuli each were collected. Results indicated that only COAs with paternal delinquency displayed significant differences from the control group, characterized by reduced P300 amplitude at frontal site and in the second trial block. Thus, the combination of fathers' alcoholism and delinquency was more likely to relate to attenuated P300 amplitude in the offspring than paternal alcoholism alone. Our results suggest that both alcoholic and delinquent family history appear to play a role in P300 amplitude reduction in the offspring.

Temporal-spatial characteristics of phase-amplitude coupling in electrocorticogram for human temporal lobe epilepsy.

PubMed

Zhang, Ruihua; Ren, Ye; Liu, Chunyan; Xu, Na; Li, Xiaoli; Cong, Fengyu; Ristaniemi, Tapani; Wang, YuPing

2017-09-01

Neural activity of the epileptic human brain contains low- and high-frequency oscillations in different frequency bands, some of which have been used as reliable biomarkers of the epileptogenic brain areas. However, the relationship between the low- and high-frequency oscillations in different cortical areas during the period from pre-seizure to post-seizure has not been completely clarified. We recorded electrocorticogram data from the temporal lobe and hippocampus of seven patients with temporal lobe epilepsy. The modulation index based on the Kullback-Leibler distance and the phase-amplitude coupling co-modulogram were adopted to quantify the coupling strength between the phase of low-frequency oscillations (0.2-10Hz) and the amplitude of high-frequency oscillations (11-400Hz) in different seizure epochs. The time-varying phase-amplitude modulogram was used to analyze the phase-amplitude coupling pattern during the entire period from pre-seizure to post-seizure in both the left and right temporal lobe and hippocampus. Channels with strong modulation index were compared with the seizure onset channels identified by the neurosurgeons and the resection channels in the clinical surgery. The phase-amplitude coupling strength (modulation index) increased significantly in the mid-seizure epoch and decrease significantly in seizure termination and post-seizure epochs (p<0.001). The strong phase-amplitude-modulating low- and high-frequency oscillations in the mid-seizure epoch were mainly δ, θ, and α oscillations and γ and ripple oscillations, respectively. The phase-amplitude modulation and strength varied among channels and was asymmetrical in the left and right temporal cortex and hippocampus. The "fall-max" phase-amplitude modulation pattern, i.e., high-frequency amplitudes were largest in the low-frequency phase range [-π, 0], which corresponded to the falling edges of low-frequency oscillations, appeared in the middle period of the seizures at epileptic focus channels. Channels with strong modulation index appeared on the corresponding left or right temporal cortex of surgical resection and overlapped with the clinical resection zones in all patients. The "fall-max" pattern between the phase of low-frequency oscillation and amplitude of high-frequency oscillation that appeared in the middle period of the seizures is a reliable biomarker in epileptogenic cortical areas. The modulation index can be used as a good tool for lateralization and localization for the epileptic focus in patients with epilepsy. Phase-amplitude coupling can provide meaningful reference for accurate resection of epileptogenic focus and provide insight into the underlying neural dynamics of the epileptic seizure in patients with temporal lobe epilepsy. Copyright © 2017 International Federation of Clinical Neurophysiology. Published by Elsevier B.V. All rights reserved.

Median and ulnar muscle and sensory evoked potentials.

PubMed

Felsenthal, G

1978-08-01

The medical literature was reviewed to find suggested clinical applications of the study of the amplitude of evoked muscle action potentials (MAP) and sensory action potentials (SAP). In addition, the literature was reviewed to ascertain the normal amplitude and duration of the evoked MAP and SAP as well as the factors affecting the amplitude: age, sex, temperature, ischemia. The present study determined the normal amplitude and duration of the median and ulnar MAP and SAP in fifty normal subjects. The amplitude of evoked muscle or sensory action potentials depends on multiple factors. Increased skin resistance, capacitance, and impedance at the surface of the recording electrode diminishes the amplitude. Similarly, increased distance from the source of the action potential diminishes its amplitude. Increased interelectrode distance increases the amplitude of the bipolarly recorded sensory action potential until a certain interelectrode distance is exceeded and the diphasic response becomes tri- or tetraphasic. Artifact or poor technique may reduce the potential difference between the recording electrodes or obscure the late positive phase of the action potential and thus diminish the peak to peak amplitude measurement. Intraindividual comparison indicated a marked difference of amplitude in opposite hands. The range of the MAP of the abductor pollicis brevis in one hand was 40.0--100% of the response in the opposite hand. For the abductor digiti minimi, the MAP was 58.5--100% of the response of the opposite hand. The median and ulnar SAP was between 50--100% of the opposite SAP. Consequent to these findings the effect of hand dominance on the amplitude of median and ulnar evoked muscle and sensory action potentials was studied in 41 right handed volunteers. The amplitudes of the median muscle action potential (p less than 0.02) and the median and ulnar sensory action potentials (p less than 0.001) were significantly less in the dominant hand. There was no significant difference between the ulnar muscle action potentials or for the median and ulnar distal motor and sensory latencies in the right and left hands of this group of volunteers.

Normal P50 Gating in Children with Autism, Yet Attenuated P50 Amplitude in the Asperger Subcategory.

PubMed

Madsen, Gitte Falcher; Bilenberg, Niels; Jepsen, Jens Richardt; Glenthøj, Birte; Cantio, Cathriona; Oranje, Bob

2015-08-01

Autism spectrum disorders (ASD) and schizophrenia are separate disorders, but there is evidence of conversion or comorbid overlap. The objective of this paper was to explore whether deficits in sensory gating, as seen in some schizophrenia patients, can also be found in a group of ASD children compared to neurotypically developed children. An additional aim was to investigate the possibility of subdividing our ASD sample based on these gating deficits. In a case-control design, we assessed gating of the P50 and N100 amplitude in 31 ASD children and 39 healthy matched controls (8-12 years) and screened for differences between groups and within the ASD group. We did not find disturbances in auditory P50 and N100 filtering in the group of ASD children as a whole, nor did we find abnormal P50 and N100 amplitudes. However, the P50 amplitude to the conditioning stimulus was significantly reduced in the Asperger subgroup compared to healthy controls. In contrast to what is usually reported for patients with schizophrenia, we found no evidence for sensory gating deficits in our group of ASD children taken as a whole. However, reduced P50 amplitude to conditioning stimuli was found in the Asperger group, which is similar to what has been described in some studies in schizophrenia patients. There was a positive correlation between the P50 amplitude of the conditioning stimuli and anxiety score in the pervasive developmental disorder not otherwise specified group, which indicates a relation between anxiety and sensory registration in this group. © 2015 International Society for Autism Research, Wiley Periodicals, Inc.

Changes of amplitude and topographical characteristics of event-related potentials during the hypnagogic period.

PubMed

Michida, N; Ebata, A; Tanaka, H; Hayashi, M; Hori, T

1999-04-01

In the previous study, during the vertex sharp wave period (hypnagogic EEG stage 4), negative components (N300, N550) were dominant at Fz and Cz in contrast to the positive component (P400) being prominent at the other areas, Pz, Oz, T5 and T6. There is no agreement regarding P400 properties during the hypnagogic period. In this study, using topographic mapping, we found that two negative components (N300, N550) and P400 independently increased their amplitude at the different areas of the scalp as arousal level lowered. The anterior negative components may reflect the information processing related to the K-complex. The P400 may reflect other activities different from the K-complex mechanism or P300 attention mechanisms.

Test-retest reliability of auditory brainstem responses to chirp stimuli in newborns.

PubMed

Cobb, Kensi M; Stuart, Andrew

2014-11-01

The purpose of this study was to examine the test-retest reliability of auditory brainstem responses (ABRs) to air- and bone-conducted chirp stimuli in newborns as a function of intensity. A repeated measures quasi-experimental design was employed. Thirty healthy newborns participated. ABRs were evoked using 60, 45, and 30 dB nHL air-conducted CE-Chirps and 45, 30, and 15 dB nHL bone-conducted CE-Chirps at a rate of 57.7/s. Measures were repeated by a second tester. Statistically significant correlations (p <.0001) and predictive linear relations (p <.0001) were found between testers for wave V latencies and amplitudes to air- and bone-conducted CE-Chirps. There were also no statistically significant differences between testers with wave V latencies and amplitudes to air- and bone-conducted CE-Chirps (p >.05). As expected, significant differences in wave V latencies and amplitudes were seen as a function of stimulus intensity for air- and bone-conducted CE-Chirps (p <.0001). These results suggest that ABRs to air- and bone-conducted CE-Chirps can be reliably repeated in newborns with different testers. The CE-Chirp may be valuable for both screening and diagnostic audiologic assessments of newborns.

The p({gamma}, {pi}{sup 0}) reaction in the {Delta}(1232) region

DOE Office of Scientific and Technical Information (OSTI.GOV)

Davidson, R.M.; Gutenberg, J.; Mukhopadhyay, N.C.

Linearly polarized photons from the Laser Electron Gamma Source (LEGS) have been used by Blanpied et al. to study the p({gamma}, {pi}{sup 0}) reaction, looking for the E2 transition amplitude in the nucleon to Delta(1232) excitation. These authors contrast their measured cross-section ratio d{sigma}{parallel}/d{sigma}{perpendicular}, with expectations of earlier analyses, by the authors and Wittman (DMW), by Nozawa et al. (NBL), and using the multipoles of Behrends and Donnachie directly, and find {open_quotes}large discrepancies{close_quotes} among them. Here the authors clarify these discrepancies. The crucial difference between DMW and NBL calculations is the inclusion of the u-channel {Delta} contribution in DMW, omittedmore » in NBL. The authors find for a fair, though not perfect, agreement with the new data: E{sub 1+}{sup {pi}}{sup 0} {r_arrow}2.1E{sub 1+}{sup {pi}}{sup 0}, keeping other multipoles fixed.« less

Increasing measurement accuracy of age-related BOLD signal change: minimizing vascular contributions by resting-state-fluctuation-of-amplitude scaling.

PubMed

Kannurpatti, Sridhar S; Motes, Michael A; Rypma, Bart; Biswal, Bharat B

2011-07-01

In this report we demonstrate a hemodynamic scaling method with resting-state fluctuation of amplitude (RSFA) in healthy adult younger and older subject groups. We show that RSFA correlated with breath hold (BH) responses throughout the brain in groups of younger and older subjects which RSFA and BH performed comparably in accounting for age-related hemodynamic coupling changes, and yielded more veridical estimates of age-related differences in task-related neural activity. BOLD data from younger and older adults performing motor and cognitive tasks were scaled using RSFA and BH related signal changes. Scaling with RSFA and BH reduced the skew of the BOLD response amplitude distribution in each subject and reduced mean BOLD amplitude and variability in both age groups. Statistically significant differences in intrasubject amplitude variation across regions of activated cortex, and intersubject amplitude variation in regions of activated cortex were observed between younger and older subject groups. Intra- and intersubject variability differences were mitigated after scaling. RSFA, though similar to BH in minimizing skew in the unscaled BOLD amplitude distribution, attenuated the neural activity-related BOLD amplitude significantly less than BH. The amplitude and spatial extent of group activation were lower in the older than in the younger group before and after scaling. After accounting for vascular variability differences through scaling, age-related decreases in activation volume were observed during the motor and cognitive tasks. The results suggest that RSFA-scaled data yield age-related neural activity differences during task performance with negligible effects from non-neural (i.e., vascular) sources. Copyright © 2010 Wiley-Liss, Inc.

The ep -->e'p eta reaction at and above the S11(1535) baryon resonance.

PubMed

Thompson, R; Dytman, S; Kim, K Y; Mueller, J; Adams, G S; Amaryan, M J; Anciant, E; Anghinolfi, M; Asavapibhop, B; Auger, T; Audit, G; Avakian, H; Barrow, S; Battaglieri, M; Beard, K; Bektasoglu, M; Bertozzi, W; Bianchi, N; Biselli, A; Boiarinov, S; Bonner, B E; Briscoe, W J; Brooks, W; Burkert, V D; Calarco, J R; Capitani, G; Carman, D S; Carnahan, B; Cole, P L; Coleman, A; Connelly, J; Cords, D; Corvisiero, P; Crabb, D; Crannell, H; Cummings, J; Day, D; Degtyarenko, P V; Demirchyan, R A; Dennis, L C; Deppman, A; De Sanctis, E; De Vita, R; Dhuga, K S; Djalali, C; Dodge, G E; Doughty, D; Dragovitsch, P; Dugger, M; Eckhause, M; Efremenko, Y V; Egiyan, H; Egiyan, K S; Elouadrhiri, L; Farhi, L; Feuerbach, R J; Ficenec, J; Fissum, K; Freyberger, A; Funsten, H; Gai, M; Gavrilov, V B; Gilfoyle, G P; Giovanetti, K; Gilad, S; Girard, P; Griffioen, K A; Guidal, M; Guillo, M; Gyurjyan, V; Hancock, D; Hardie, J; Heddle, D; Heisenberg, J; Hersman, F W; Hicks, K; Hicks, R S; Holtrop, M; Hyde-Wright, C E; Ito, M M; Jenkins, D; Joo, K; Kane, J; Khandaker, M; Kim, W; Klein, A; Klein, F J; Klusman, M; Kossov, M; Kuhn, S E; Kuang, Y; Laget, J M; Lawrence, D; Leskin, G A; Longhi, A; Loukachine, K; Lucas, M; Magahiz, R; Major, R W; Manak, J J; Marchand, C; Matthews, S K; McAleer, S; McCarthy, J; McNabb, J W; Mecking, B A; Mestayer, M D; Meyer, C A; Minehart, R; Mirazita, M; Miskimen, R; Muccifora, V; Mutchler, G S; Napolitano, J; Niyazov, R A; Ohandjanyan, M S; O'Brien, J T; Opper, A; Patois, Y; Peterson, G A; Philips, S; Pivnyuk, N; Pocanic, D; Pogorelko, O; Polli, E; Preedom, B M; Price, J W; Qin, L M; Raue, B A; Reolon, A R; Riccardi, G; Ricco, G; Ripani, M; Ritchie, B G; Ronchetti, F; Rossi, P; Roudot, F; Rowntree, D; Rubin, P D; Salgado, C W; Sanzone, M; Sapunenko, V; Sarty, A; Sargsyan, M; Schumacher, R A; Shafi, A; Sharabian, Y G; Shaw, J; Shuvalov, S M; Skabelin, A; Smith, T; Smith, C; Smith, E S; Sober, D I; Spraker, M; Stepanyan, S; Stoler, P; Taiuti, M; Taylor, S; Tedeschi, D; Tung, T Y; Vineyard, M F; Vlassov, A; Weller, H; Weinstein, L B; Welsh, R; Weygand, D P; Whisnant, S; Witkowski, M; Wolin, E; Yegneswaran, A; Yun, J; Zhou, Z; Zhao, J

2001-02-26

New cross sections for the reaction e p-->e p eta are reported for total center of mass energy W = 1.5--1.86 GeV and invariant momentum transfer Q2 = 0.25--1.5 (GeV/c)(2). This large kinematic range allows extraction of important new information about response functions, photocouplings, and eta N coupling strengths of baryon resonances. Newly observed structure at W approximately 1.65 GeV is shown to come from interference between S and P waves and can be interpreted with known resonances. Improved values are derived for the photon coupling amplitude for the S11(1535) resonance.

A case-matched study of neurophysiological correlates to attention/working memory in people with somatic hypervigilance.

PubMed

Berryman, Carolyn; Wise, Vikki; Stanton, Tasha R; McFarlane, Alexander; Moseley, G Lorimer

2017-02-01

Somatic hypervigilance describes a clinical presentation in which people report more, and more intense, bodily sensations than is usual. Most explanations of somatic hypervigilance implicate altered information processing, but strong empirical data are lacking. Attention and working memory are critical for information processing, and we aimed to evaluate brain activity during attention/working memory tasks in people with and without somatic hypervigilance. Data from 173 people with somatic hypervigilance and 173 controls matched for age, gender, handedness, and years of education were analyzed. Event-related potential (ERP) data, extracted from the continuous electroencephalograph recordings obtained during performance of the Auditory Oddball task, and the Two In A Row (TIAR) task, for N1, P2, N2, and P3, were used in the analysis. Between-group differences for P3 amplitude and N2 amplitude and latency were assessed with two-tailed independent t tests. Between-group differences for N1 and P2 amplitude and latency were assessed using mixed, repeated measures analyses of variance (ANOVAs) with group and Group × Site factors. Linear regression analysis investigated the relationship between anxiety and depression and any outcomes of significance. People with somatic hypervigilance showed smaller P3 amplitudes-Auditory Oddball task: t(285) = 2.32, 95% confidence interval, CI [3.48, 4.47], p = .026, d = 0.27; Two-In-A-Row (TIAR) task: t(334) = 2.23, 95% CI [2.20; 3.95], p = .021, d = 0.24-than case-matched controls. N2 amplitude was also smaller in people with somatic hypervigilance-TIAR task: t(318) = 2.58, 95% CI [0.33, 2.47], p = .010, d = 0.29-than in case-matched controls. Neither depression nor anxiety was significantly associated with any outcome. People with somatic hypervigilance demonstrated an event-related potential response to attention/working memory tasks that is consistent with altered information processing.

Dynamic Characteristics of Ventilatory and Gas Exchange during Sinusoidal Walking in Humans.

PubMed

Fukuoka, Yoshiyuki; Iihoshi, Masaaki; Nazunin, Juhelee Tuba; Abe, Daijiro; Fukuba, Yoshiyuki

2017-01-01

Our present study investigated whether the ventilatory and gas exchange responses show different dynamics in response to sinusoidal change in cycle work rate or walking speed even if the metabolic demand was equivalent in both types of exercise. Locomotive parameters (stride length and step frequency), breath-by-breath ventilation (V̇E) and gas exchange (CO2 output (V̇CO2) and O2 uptake (V̇O2)) responses were measured in 10 healthy young participants. The speed of the treadmill was sinusoidally changed between 3 km·h-1 and 6 km·h-1 with various periods (from 10 to 1 min). The amplitude of locomotive parameters against sinusoidal variation showed a constant gain with a small phase shift, being independent of the oscillation periods. In marked contrast, when the periods of the speed oscillations were shortened, the amplitude of V̇E decreased sharply whereas the phase shift of V̇E increased. In comparing walking and cycling at the equivalent metabolic demand, the amplitude of V̇E during sinusoidal walking (SW) was significantly greater than that during sinusoidal cycling (SC), and the phase shift became smaller. The steeper slope of linear regression for the V̇E amplitude ratio to V̇CO2 amplitude ratio was observed during SW than SC. These findings suggested that the greater amplitude and smaller phase shift of ventilatory dynamics were not equivalent between SW and SC even if the metabolic demand was equivalent between both exercises. Such phenomenon would be derived from central command in proportion to locomotor muscle recruitment (feedforward) and muscle afferent feedback.

$eta$ production at high Q^2

DOE Office of Scientific and Technical Information (OSTI.GOV)

M.K. Jones

2012-04-01

The differential cross-sections for the p(e,e'p){eta} reaction have been measured in Hall C at Jefferson Lab at Q{sup 2} = 5.7 and 7.0 (GeV/c){sup 2} for center-of-mass energies from threshold to 1.8 GeV, encompassing the S{sub 11}(1535) resonance, which dominates the reaction. From fits to the data, the S{sub 11}(1535) helicity conserving photo-coupling amplitude, A{sub 1/2}, was extracted.

The time course of implicit processing of erotic pictures: an event-related potential study.

PubMed

Feng, Chunliang; Wang, Lili; Wang, Naiyi; Gu, Ruolei; Luo, Yue-Jia

2012-12-13

The current study investigated the time course of the implicit processing of erotic stimuli using event-related potentials (ERPs). ERPs elicited by erotic pictures were compared with those by three other types of pictures: non-erotic positive, negative, and neutral pictures. We observed that erotic pictures evoked enhanced neural responses compared with other pictures at both early (P2/N2) and late (P3/positive slow wave) temporal stages. These results suggested that erotic pictures selectively captured individuals' attention at early stages and evoked deeper processing at late stages. More importantly, the amplitudes of P2, N2, and P3 only discriminated between erotic and non-erotic (i.e., positive, neutral, and negative) pictures. That is, no difference was revealed among non-erotic pictures, although these pictures differed in both valence and arousal. Thus, our results suggest that the erotic picture processing is beyond the valence and arousal. Copyright © 2012 Elsevier B.V. All rights reserved.

Age-related changes in laser-evoked potentials following trigeminal and hand stimulation in healthy subjects.

PubMed

de Tommaso, M; Ricci, K; Montemurno, A; Vecchio, E

2017-07-01

This study aimed to evaluate age-related changes in laser-evoked potential (LEP) features, including habituation, via trigeminal and hand stimulation in a large group of healthy volunteers. We recorded the LEPs by right-hand stimulation in 237 healthy subjects and by stimulation of the right supraorbital zone in 170 cases. The subjects ranged in age from 7 to 72 years and were divided into six groups by age. At the trigeminal level, the N2 and P2 latencies were significantly shorter and the N2-P2 amplitude was significantly larger in the 7-17 age group than in the other groups. The N2-P2 amplitude of the responses evoked by hand stimulation was significantly larger in the 7-40 age range than in the older subjects. The N1 amplitude and latency were not significantly different among the groups. The N2-P2 habituation increased with age, but no significant changes among groups were revealed by the Bonferroni test. Trigeminal vertex LEPs have greater amplitudes and appear earlier in children, while a progressive age-related amplitude decrease characterizes the N2-P2 waves associated with hand stimulation. The N2-P2 habituation increases in older people. The N1 latency and amplitude seem to remain stable during ageing and are therefore potentially reliable and useful patterns for nociceptive system examination. Standardization of age-related changes in trigeminal and hand LEPs is possible and should improve their reliability in the objective assessment of pain pathways. © 2017 European Pain Federation - EFIC®.

Electrophysiology of Memory-Updating Differs with Age

PubMed Central

Steiner, Genevieve Z.; Gonsalvez, Craig J.; De Blasio, Frances M.; Barry, Robert J.

2016-01-01

In oddball tasks, the P3 component of the event-related potential systematically varies with the time between target stimuli—the target-to-target interval (TTI). Longer TTIs result in larger P3 amplitudes and shorter latencies, and this pattern of results has been linked with working memory-updating processes. Given that working memory and the P3 have both been shown to diminish with age, the current study aimed to determine whether the linear relationship between P3 and TTI is compromised in healthy aging by comparing TTI effects on P3 amplitudes and latencies, and reaction time (RT), in young and older adults. Older adults were found to have an overall reduction in P3 amplitudes, longer latencies, an anterior shift in topography, a trend toward slower RTs, and a flatter linear relationship between P3 and TTI than young adults. Results suggest that the ability to maintain templates in working memory required for stimulus categorization decreases with age, and that as a result, neural compensatory mechanisms are employed. PMID:27378908

Electrophysiology of Memory-Updating Differs with Age.

PubMed

Steiner, Genevieve Z; Gonsalvez, Craig J; De Blasio, Frances M; Barry, Robert J

2016-01-01

In oddball tasks, the P3 component of the event-related potential systematically varies with the time between target stimuli-the target-to-target interval (TTI). Longer TTIs result in larger P3 amplitudes and shorter latencies, and this pattern of results has been linked with working memory-updating processes. Given that working memory and the P3 have both been shown to diminish with age, the current study aimed to determine whether the linear relationship between P3 and TTI is compromised in healthy aging by comparing TTI effects on P3 amplitudes and latencies, and reaction time (RT), in young and older adults. Older adults were found to have an overall reduction in P3 amplitudes, longer latencies, an anterior shift in topography, a trend toward slower RTs, and a flatter linear relationship between P3 and TTI than young adults. Results suggest that the ability to maintain templates in working memory required for stimulus categorization decreases with age, and that as a result, neural compensatory mechanisms are employed.

Open- and Closed-Skill Exercise Interventions Produce Different Neurocognitive Effects on Executive Functions in the Elderly: A 6-Month Randomized, Controlled Trial

PubMed Central

Tsai, Chia-Liang; Pan, Chien-Yu; Chen, Fu-Chen; Tseng, Yu-Ting

2017-01-01

This study aimed to explore the effects of open- and closed-skill exercise interventions on the neurocognitive performance of executive functions in the elderly. Sixty-four healthy elderly males were randomly assigned to either a closed-skill (bike riding or brisk walking/jogging, n = 22), open-skill (table tennis, n = 21), or control (n = 21) group. Various neuropsychological [e.g., accuracy rates (AR) and reaction time (RT)] and electrophysiological [e.g., event-related potential (ERP) P3 component] measures were assessed during a variant of the task-switching paradigm, as well as an N-back task at baseline and after either a 6-month exercise intervention or control period. The results showed that, when performing the task-switching paradigm, the two exercise groups relative to control group showed significantly faster RTs in the switch trials after the exercise intervention. However, the RT facilitation in the non-switch and switch trials post-exercise relative to pre-exercise only emerged in the open-skill group. In terms of the N-back task, the two exercise groups significantly increased ARs in the 1-back condition after the exercise intervention, and the beneficial AR effect on the 2-back condition only emerged in the closed-skill group. In addition, the two exercise groups exhibited significantly larger P3 amplitudes on the frontal-to-parietal cortex areas after the exercise intervention relative to the baseline when performing the two cognitive tasks. These neurocognitive results still remained unchanged even when the confounding factors (e.g., cardiorespiratory fitness, social participation, and BMI) were controlled for. The present study concluded that, although 6-month open- and closed-skill exercise interventions facilitate overall electrophysiological effects (i.e., increased ERP P3 amplitudes) on the frontal-to-parietal cortices in the elderly, the two exercise modes produced different levels of neuropsychologically beneficial effects on RTs of the task-switching paradigm (i.e., lessened RTs) and ARs of the N-back task (i.e., enhanced ARs). The distinctive neurocognitive changes induced by open- and closed-skill exercise have implications for task switching and working memory in elderly individuals, especially with such cognitive functioning impairments. PMID:28959200

Effect of the third π ∗ resonance on the angular distributions for electron-pyrimidine scattering

NASA Astrophysics Data System (ADS)

Mašín, Zdeněk; Gorfinkiel, Jimena D.

2016-07-01

We present a detailed analysis of the effect of the well known third π∗ resonance on the angular behaviour of the elastic cross section in electron scattering from pyrimidine. This resonance, occurring approximately at 4.7 eV, is of mixed shape and core-excited character. Experimental and theoretical results show the presence of a peak/dip behaviour in this energy range, that is absent for other resonances. Our investigations show that the cause of the peak/dip is an interference of background p-wave to p-wave scattering amplitudes with the amplitudes for resonant scattering. The equivalent resonance in pyrazine shows the same behaviour and the effect is therefore likely to appear in other benzene-like molecules. Contribution to the Topical Issue "Advances in Positron and Electron Scattering", edited by Paulo Limao-Vieira, Gustavo Garcia, E. Krishnakumar, James Sullivan, Hajime Tanuma and Zoran Petrovic.

Teleseismic Lg of Semipalatinsk and Novaya Zemlya Nuclear Explosions Recorded by the GRF (Gräfenberg) Array: Comparison with Regional Lg (BRV) and their Potential for Accurate Yield Estimation

NASA Astrophysics Data System (ADS)

Schlittenhardt, J.

- A comparison of regional and teleseismic log rms (root-mean-square) Lg amplitude measurements have been made for 14 underground nuclear explosions from the East Kazakh test site recorded both by the BRV (Borovoye) station in Kazakhstan and the GRF (Gräfenberg) array in Germany. The log rms Lg amplitudes observed at the BRV regional station at a distance of 690km and at the teleseismic GRF array at a distance exceeding 4700km show very similar relative values (standard deviation 0.048 magnitude units) for underground explosions of different sizes at the Shagan River test site. This result as well as the comparison of BRV rms Lg magnitudes (which were calculated from the log rms amplitudes using an appropriate calibration) with magnitude determinations for P waves of global seismic networks (standard deviation 0.054 magnitude units) point to a high precision in estimating the relative source sizes of explosions from Lg-based single station data. Similar results were also obtained by other investigators (Patton, 1988; Ringdaletal., 1992) using Lg data from different stations at different distances.Additionally, GRF log rms Lg and P-coda amplitude measurements were made for a larger data set from Novaya Zemlya and East Kazakh explosions, which were supplemented with mb(Lg) amplitude measurements using a modified version of Nuttli's (1973, 1986a) method. From this test of the relative performance of the three different magnitude scales, it was found that the Lg and P-coda based magnitudes performed equally well, whereas the modified Nuttli mb(Lg) magnitudes show greater scatter when compared to the worldwide mb reference magnitudes. Whether this result indicates that the rms amplitude measurements are superior to the zero-to-peak amplitude measurement of a single cycle used for the modified Nuttli method, however, cannot be finally assessed, since the calculated mb(Lg) magnitudes are only preliminary until appropriate attenuation corrections are available for the specific path to GRF.

Culture and context: East Asian American and European American differences in P3 event-related potentials and self-construal.

PubMed

Lewis, Richard S; Goto, Sharon G; Kong, Lauren L

2008-05-01

Research has demonstrated differences in social and cognitive processes between East Asians and European Americans. Whereas East Asians have been characterized as being more sensitive to situational context and attending more to the perceptual field, European Americans have been characterized as being more focused on the object and being more field independent. The goal of the present experiment was to investigate differences in neural responses to target objects and stimulus context between East Asian Americans and European Americans using a three-stimulus novelty P3 event-related potential design. As hypothesized, European Americans displayed relatively greater target P3 amplitudes, indexing attention to target events, whereas East Asian Americans displayed relatively greater novelty P3 amplitudes, indexing attention to contextually deviant events. Furthermore, the authors found that interdependent self-construal mediated the relationship between culture and the novelty P3. These findings identify a specific pattern of neural activity associated with established cultural differences in contextual sensitivity.

A fast visual evoked potential method for functional assessment and follow-up of childhood optic gliomas.

PubMed

Trisciuzzi, Maria Teresa S; Riccardi, Riccardo; Piccardi, Marco; Iarossi, Giancarlo; Buzzonetti, Luca; Dickmann, Anna; Colosimo, Cesare; Ruggiero, Antonio; Di Rocco, Concezio; Falsini, Benedetto

2004-01-01

To evaluate a fast technique of visual evoked potentials (VEPs) recording, in response to steady-state luminance stimuli (SS-LVEPs), for functional assessment and follow-up of childhood optic gliomas (OGs). Eighteen OG patients (age range: 3.5-18 years), with different degrees of optic pathway damage severity, were examined. Sixteen age-matched normal subjects served as controls. Ten of the 18 OG patients were re-tested 1-3 months after the first examination. SS-LVEPs were elicited by a sinusoidally-modulated flickering (8 Hz) uniform field, generated by a light emitting diode (LED)-array and presented monocularly in a mini-ganzfeld. Amplitude and phase of the Fourier-analyzed response fundamental (1F) and second harmonic (2F) were measured. The full VEP protocol had a median duration of 6 min (range: 4-12). When compared to normal control values, median 1F and 2F SS-LVEP amplitudes of OG patients were reduced (P<0.01), with a borderline increase in 2F phase lag (P<0.05). In 11 OG patients with asymmetric optic pathway damage in between-eye comparisons, median 1F amplitude losses were greater (P<0.01) in fellow eyes with more severe damage. No significant interocular difference was observed in control subjects. Median test-retest changes of 1F and 2F component were <20% and 30 degrees for amplitude and phase, respectively. In individual OG patients, 1F and 2F amplitudes were positively correlated (P<0.01) with visual acuity. 1F amplitude losses were correlated (P=0.01) with the severity of optic disc atrophy. Considering both 1F and 2F abnormalities, diagnostic sensitivity of SS-LVEP in detecting OG-induced optic pathways damage was 83.3%. The present findings support the use of this technique, as an alternative to pattern VEPs, for functional assessment and follow-up of OG in uncooperative children.

One-dimensional kinetic description of nonlinear traveling-pulse and traveling-wave disturbances in long coasting charged particle beams

DOE PAGES

Davidson, Ronald C.; Qin, Hong

2015-09-21

This study makes use of a one-dimensional kinetic model to investigate the nonlinear longitudinal dynamics of a long coasting beam propagating through a perfectly conducting circular pipe with radius r w. The average axial electric field is expressed as < E z >=-(∂/∂z)=-e bg 0∂λ b/∂z-e bg 2r 2 w∂ 3λ b/∂z 3, where g 0 and g 2 are constant geometric factors, λ b(z,t)=∫dp zF b(z,p z,t) is the line density of beam particles, and F b(z,p z,t) satisfies the 1D Vlasov equation. Detailed nonlinear properties of traveling-wave and traveling-pulse (soliton) solutions with time-stationary waveform are examined for amore » wide range of system parameters extending from moderate-amplitudes to large-amplitude modulations of the beam charge density. Two classes of solutions for the beam distribution function are considered, corresponding to: (i) the nonlinear waterbag distribution, where F b=const in a bounded region of p z-space; and (ii) nonlinear Bernstein-Green-Kruskal (BGK)-like solutions, allowing for both trapped and untrapped particle distributions to interact with the self-generated electric field < E z >.« less

One-dimensional kinetic description of nonlinear traveling-pulse and traveling-wave disturbances in long coasting charged particle beams

DOE Office of Scientific and Technical Information (OSTI.GOV)

Davidson, Ronald C.; Qin, Hong

This study makes use of a one-dimensional kinetic model to investigate the nonlinear longitudinal dynamics of a long coasting beam propagating through a perfectly conducting circular pipe with radius r w. The average axial electric field is expressed as < E z >=-(∂/∂z)=-e bg 0∂λ b/∂z-e bg 2r 2 w∂ 3λ b/∂z 3, where g 0 and g 2 are constant geometric factors, λ b(z,t)=∫dp zF b(z,p z,t) is the line density of beam particles, and F b(z,p z,t) satisfies the 1D Vlasov equation. Detailed nonlinear properties of traveling-wave and traveling-pulse (soliton) solutions with time-stationary waveform are examined for amore » wide range of system parameters extending from moderate-amplitudes to large-amplitude modulations of the beam charge density. Two classes of solutions for the beam distribution function are considered, corresponding to: (i) the nonlinear waterbag distribution, where F b=const in a bounded region of p z-space; and (ii) nonlinear Bernstein-Green-Kruskal (BGK)-like solutions, allowing for both trapped and untrapped particle distributions to interact with the self-generated electric field < E z >.« less

N400 elicited by incongruent ending words of Chinese idioms in healthy adults.

PubMed

Chen, Xing-shi; Tang, Yun-xiang; Xiao, Ze-ping; Wang, Ji-jun; Zhang, Ming-dao; Zhang, Zai-fu; Hu, Zhen-yu; Lou, Fei-ying; Chen, Chong; Zhang, Tian-hong

2010-03-20

Prior research about N400 has been mainly based on English stimuli, while the cognitive processing of Chinese characters is still unclear. The aim of the present study was to further investigate the semantic processing of Chinese idioms. Event related potentials (ERP) component N400 was elicited by 38 pairs of matching (congruent) and mismatching (incongruent) ended Chinese idioms: ending words with same phoneme but different shape and meaning (sPdSdM), with similar shape but different phoneme and meaning (sSdPdM), with same meaning but different phoneme and shape (sMdPdS), and words with different phoneme, shape and meaning (dPdSdM) and recorded by Guangzhou Runjie WJ-1 ERP instruments. In 62 right-handed healthy adults (age 19 - 50 years), N400 amplitudes and latencies were compared between matching and mismatching conditions at Fz, Cz and Pz. N400 showed a midline distribution and could be elicited in electrodes Fz, Cz and Pz. The mean values of N400 latencies and amplitudes were obtained for matching and mismatching ending words in healthy adults. Significant differences were found in N400 latencies and amplitudes in matching and mismatching ending-words idioms in healthy adults (P < 0.05). Compared with matching ending-words idioms, N400 latencies were prolonged and the amplitudes were increased in mismatching ones. N400s elicited by different types of stimuli showed different latencies and amplitudes, and longest N400 latency and largest N400 amplitude were elicited by ending-words with dPdSdM. No gender difference was found of N400 latency and amplitude in this study (P > 0.05). Compared with English stimuli, Chinese ideographic words could provide more flexible stimuli for N400 research in that the words have 3-dimension changes - phoneme, shape and meaning. Features of N400 elicited by matching and mismatching ending words in Chinese idioms are mainly determined by the meaning of the word. Some issues of N400 elicited by Chinese characters deserve further research.

Pseudo-scalar pi N coupling and relativistic proton-nucleus scattering

NASA Technical Reports Server (NTRS)

Gross, Franz; Maung, Khin Maung; Tjon, J. A.; Townsend, L. W.; Wallace, S. J.

1988-01-01

Relativistic p-Ca-40 elastic scattering observables are calculated using relativistic NN amplitudes obtained from the solution of a two-body relativistic equation in which one particle is kept on its mass-shell. Results at 200 MeV are presented for two sets of NN amplitudes, one with pure pseudo-vector coupling for the pion and another with a 25 percent admixture of pseudo-scaling coupling. Both give a very good fit to the positive energy on-shell NN data. Differences between the predictions of these two models (which are shown to be due only to the differences in their corresponding negative energy amplitudes) provide a measure of the uncertainty in contructing Dirac optical potentials from NN amplitudes.

Utility of event-related potentials in predicting antidepressant treatment response: An iSPOT-D report.

PubMed

van Dinteren, Rik; Arns, Martijn; Kenemans, Leon; Jongsma, Marijtje L A; Kessels, Roy P C; Fitzgerald, Paul; Fallahpour, Kamran; Debattista, Charles; Gordon, Evian; Williams, Leanne M

2015-11-01

It is essential to improve antidepressant treatment of major depressive disorder (MDD) and one way this could be achieved is by reducing the number of treatment steps by employing biomarkers that can predict treatment outcome. This study investigated differences between MDD patients and healthy controls in the P3 and N1 component from the event-related potential (ERP) generated in a standard two-tone oddball paradigm. Furthermore, the P3 and N1 are investigated as predictors for treatment outcome to three different antidepressants. In the international Study to Predict Optimized Treatment in Depression (iSPOT-D)--a multi-center, international, randomized, prospective practical trial--1008 MDD participants were randomized to escitalopram, sertraline or venlafaxine-XR. The study also recruited 336 healthy controls. Treatment response and remission were established after eight weeks using the 17-item Hamilton Rating Scale for Depression. P3 and N1 latencies and amplitudes were analyzed using a peak-picking approach and further replicated by using exact low resolution tomography (eLORETA). A reduced P3 was found in MDD patients compared to controls by a peak-picking analysis. This was validated in a temporal global field power analysis. Source density analysis revealed that the difference in cortical activity originated from the posterior cingulate and parahippocampal gyrus. Male non-responders to venlafaxine-XR had significantly smaller N1 amplitudes than responders. This was demonstrated by both analytical methods. Male non-responders to venlafaxine-XR had less activity originating from the left insular cortex. The observed results are discussed from a neural network viewpoint. Copyright © 2015 Elsevier B.V. and ECNP. All rights reserved.

[Effect of prokinetic agents on the electrical activity of stomach and duodenum in rats].

PubMed

Li, Fujun; Zou, Yiyou; Huang, Tianhui

2009-07-01

To determine the effect of prokinetic agents such as domperidone, mosapride, clarithromycin, and itopride on the electrical activity of the stomach and duodenum in SD rats,and also to explore the mechanism. The organism functional experiment system BL-420E was used to record the myoelectrical activity in the stomach and duodenum of SD rats in all groups using domperidone, mosapride, itopride, clarithromycin, and physiological saline on the interdigestive phase. The effect of the prokinetic agents on the amplitude and frequency of gastric and duodenal electromyogram in the SD rats was compared. The antagonists such as atropine, phentolamine, and propranolol were added to investigate the mechanism of action with all prokinetic agents. All prokinetic agents increased the amplitude and frequency of gastric and duodenal fast waves in the SD rats(P<0.05). The effect of itopride was the most obvious among the 3 groups (P<0.05),and clarithromycin had the weakest effect(P<0.05). The amplitude and frequency of gastric and duodenal fast waves in the SD rats in the groups of clarithromycin,domperidone,mosapride, itopride, and physiological saline were inhibited by atropine(P<0.05),but not by phentolamine and propranolol. Itopride, mosapride, domperidone, and clarithromycin can increase the amplitude and frequency of gastric and duodenal fast waves in the SD rats. The mechanism may be related to cholinergic receptors, but not adrenergic receptors.

The temporal dynamics of reversal learning: P3 amplitude predicts valence-specific behavioral adjustment.

PubMed

Donaldson, Kayla R; Ait Oumeziane, Belel; Hélie, Sebastien; Foti, Dan

2016-07-01

Adapting behavior to dynamic stimulus-reward contingences is a core feature of reversal learning and a capacity thought to be critical to socio-emotional behavior. Impairment in reversal learning has been linked to multiple psychiatric outcomes, including depression, Parkinson's disorder, and substance abuse. A recent influential study introduced an innovative laboratory reversal-learning paradigm capable of disentangling the roles of feedback valence and expectancy. Here, we sought to use this paradigm in order to examine the time-course of reward and punishment learning using event-related potentials among a large, representative sample (N=101). Three distinct phases of processing were examined: initial feedback evaluation (reward positivity, or RewP), allocation of attention (P3), and sustained processing (late positive potential, or LPP). Results indicate a differential pattern of valence and expectancy across these processing stages: the RewP was uniquely related to valence (i.e., positive vs. negative feedback), the P3 was uniquely associated with expectancy (i.e., unexpected vs. expected feedback), and the LPP was sensitive to both valence and expectancy (i.e., main effects of each, but no interaction). The link between ERP amplitudes and behavioral performance was strongest for the P3, and this association was valence-specific. Overall, these findings highlight the potential utility of the P3 as a neural marker for feedback processing in reversal-based learning and establish a foundation for future research in clinical populations. Copyright © 2016 Elsevier Inc. All rights reserved.

Correlation between bithermal caloric test results and vestibular evoked myogenic potentials (VEMPs) in normal subjects.

PubMed

Andrade, Isabel Vaamonde Sanchez; Santos-Perez, Sofia; Diz, Pilar Gayoso; Caballero, Torcuato Labella; Soto-Varela, Andrés

2013-05-01

Bithermal caloric testing and vestibular evoked myogenic potentials (VEMPs) are both diagnostic tools for the study of the vestibular system. The first tests the horizontal semicircular canal and the second evaluates the saccule and lower vestibular nerve. The results of these two tests can therefore be expected to be correlated. The aim of this study was to compare bithermal caloric test results with VEMP records in normal subjects to verify whether they are correlated. A prospective study was conducted in 60 healthy subjects (30 men and 30 women) who underwent otoscopy, pure tone audiometry, bithermal caloric testing and VEMPs. From the caloric test, we assessed the presence of possible vestibular hypofunction, whether there was directional preponderance and reflectivity of each ear (all based on both slow phase velocity and nystagmus frequency). The analysed VEMPs variables were: p1 and n1 latency, corrected amplitude, interaural p1 latency difference and p1 interaural amplitude asymmetry. We compared the reflectivity, hypofunction and directional preponderance of the caloric tests with the corrected amplitudes and amplitude asymmetries of the VEMPs. No correlations were found in the different comparisons between bithermal caloric testing results and VEMPs except for a weak correlation (p = 0.039) when comparing preponderance based on the number of nystagmus in the caloric test and amplitude asymmetry with 99 dB tone burst in the VEMPs test. The results indicate that the two diagnostic tests are not comparable, so one of them cannot replace the other, but the use of both increases diagnostic success in some conditions.

REGIONAL SEISMIC AMPLITUDE MODELING AND TOMOGRAPHY FOR EARTHQUAKE-EXPLOSION DISCRIMINATION

DOE Office of Scientific and Technical Information (OSTI.GOV)

Walter, W R; Pasyanos, M E; Matzel, E

2008-07-08

We continue exploring methodologies to improve earthquake-explosion discrimination using regional amplitude ratios such as P/S in a variety of frequency bands. Empirically we demonstrate that such ratios separate explosions from earthquakes using closely located pairs of earthquakes and explosions recorded on common, publicly available stations at test sites around the world (e.g. Nevada, Novaya Zemlya, Semipalatinsk, Lop Nor, India, Pakistan, and North Korea). We are also examining if there is any relationship between the observed P/S and the point source variability revealed by longer period full waveform modeling (e. g. Ford et al 2008). For example, regional waveform modeling showsmore » strong tectonic release from the May 1998 India test, in contrast with very little tectonic release in the October 2006 North Korea test, but the P/S discrimination behavior appears similar in both events using the limited regional data available. While regional amplitude ratios such as P/S can separate events in close proximity, it is also empirically well known that path effects can greatly distort observed amplitudes and make earthquakes appear very explosion-like. Previously we have shown that the MDAC (Magnitude Distance Amplitude Correction, Walter and Taylor, 2001) technique can account for simple 1-D attenuation and geometrical spreading corrections, as well as magnitude and site effects. However in some regions 1-D path corrections are a poor approximation and we need to develop 2-D path corrections. Here we demonstrate a new 2-D attenuation tomography technique using the MDAC earthquake source model applied to a set of events and stations in both the Middle East and the Yellow Sea Korean Peninsula regions. We believe this new 2-D MDAC tomography has the potential to greatly improve earthquake-explosion discrimination, particularly in tectonically complex regions such as the Middle East. Monitoring the world for potential nuclear explosions requires characterizing seismic events and discriminating between natural and man-made seismic events, such as earthquakes and mining activities, and nuclear weapons testing. We continue developing, testing, and refining size-, distance-, and location-based regional seismic amplitude corrections to facilitate the comparison of all events that are recorded at a particular seismic station. These corrections, calibrated for each station, reduce amplitude measurement scatter and improve discrimination performance. We test the methods on well-known (ground truth) datasets in the U.S. and then apply them to the uncalibrated stations in Eurasia, Africa, and other regions of interest to improve underground nuclear test monitoring capability.« less

Amplitude analysis of elastic p-p scattering at 6 GeV/c at all t's

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ghahramany, N.; Goldstein, G.R.; Moravcsik, M.J.

1983-09-01

The extensive set of polarization data obtained at the Argonne Zero Gradient Synchro- p tron for elastic proton-proton scattering at 6 GeV/c at a full set of values of t is used to determine the five complex reaction amplitudes, using the optimal formalism. The determination is easiest in the transversity formalism, and from that the ''planar'' amplitudes (including the helicity amplitudes) are obtained. A complete determination is made at 20 different values of t, from -0.1 to -1.0 (GeV/c)/sup 2/, using data interpolated in t. In addition, a less complete set of data permits the determination of the five magnitudesmore » (but not of the four phases) in the range from t = -1.0 to t = -2.0 (GeV/c)/sup 2/. The magnitudes of the five amplitudes can be obtained without any ambiguity, but for the four relative phases several distinct solutions exist, one of which is selected on the basis of continuity in t and minimum chi/sup 2/. There continues to be evidence that in the planar system in which the orientation axes are 90/sup 0/ from the helicity axes, all amplitudes tend to be either pure real or pure imaginary.« less

EEG correlates of visual short-term memory as neuro-cognitive endophenotypes of ADHD.

PubMed

Wiegand, Iris; Hennig-Fast, Kristina; Kilian, Beate; Müller, Hermann J; Töllner, Thomas; Möller, Hans-Jürgen; Engel, Rolf R; Finke, Kathrin

2016-05-01

Attention deficit hyperactivity disorder (ADHD) frequently persists into adulthood. A reduction in visual short-term memory (vSTM) storage capacity was recently suggested as a potential neuro-cognitive endophenotype, i.e., a testable marker of an individual's liability for developing ADHD. This study aimed at identifying markers of the brain abnormalities underlying vSTM reductions in adult ADHD. We combined behavioral parameter-based assessment with electrophysiology in groups of adult ADHD patients and healthy age-matched controls. Amplitudes of ERP markers of vSTM storage capacity, the contralateral delay activity (CDA) and the P3b, were analyzed according to (i) differences between individuals with higher vs. lower storage capacity K and (ii) differences between ADHD patients and control participants. We replicated the finding of reduced storage capacity in adult ADHD. Across groups, individuals with higher relative to lower storage capacity showed a larger CDA and P3b. We further found differences between the patient and control groups in the ERPs: The CDA amplitude was attenuated in an early time window for ADHD patients compared to control participants, and was negatively correlated with ADHD patients' symptom severity ratings. Furthermore, the P3b was larger in ADHD patients relative to control participants. These electrophysiological findings indicate altered brain mechanisms underlying visual storage capacity in ADHD, which are characterized by deficient encoding and maintenance, and increased recruitment of control processes. Accordingly, (quantifiable) ERP markers of vSTM in adult ADHD bear candidacy as neuro-cognitive endophenotypes of the disease. Copyright © 2016 Elsevier Ltd. All rights reserved.

Cortical Sensitivity to Guitar Note Patterns: EEG Entrainment to Repetition and Key.

PubMed

Bridwell, David A; Leslie, Emily; McCoy, Dakarai Q; Plis, Sergey M; Calhoun, Vince D

2017-01-01

Music is ubiquitous throughout recent human culture, and many individual's have an innate ability to appreciate and understand music. Our appreciation of music likely emerges from the brain's ability to process a series of repeated complex acoustic patterns. In order to understand these processes further, cortical responses were measured to a series of guitar notes presented with a musical pattern or without a pattern. ERP responses to individual notes were measured using a 24 electrode Bluetooth mobile EEG system (Smarting mBrainTrain) while 13 healthy non-musicians listened to structured (i.e., within musical keys and with repetition) or random sequences of guitar notes for 10 min each. We demonstrate an increased amplitude to the ERP that appears ~200 ms to notes presented within the musical sequence. This amplitude difference between random notes and patterned notes likely reflects individual's cortical sensitivity to guitar note patterns. These amplitudes were compared to ERP responses to a rare note embedded within a stream of frequent notes to determine whether the sensitivity to complex musical structure overlaps with the sensitivity to simple irregularities reflected in traditional auditory oddball experiments. Response amplitudes to the negative peak at ~175 ms are statistically correlated with the mismatch negativity (MMN) response measured to a rare note presented among a series of frequent notes (i.e., in a traditional oddball sequence), but responses to the subsequent positive peak at ~200 do not show a statistical relationship with the P300 response. Thus, the sensitivity to musical structure identified to 4 Hz note patterns appears somewhat distinct from the sensitivity to statistical regularities reflected in the traditional "auditory oddball" sequence. Overall, we suggest that this is a promising approach to examine individual's sensitivity to complex acoustic patterns, which may overlap with higher level cognitive processes, including language.

Mild Airflow Limitation during N2 Sleep Increases K-complex Frequency and Slows Electroencephalographic Activity.

PubMed

Nguyen, Chinh D; Wellman, Andrew; Jordan, Amy S; Eckert, Danny J

2016-03-01

To determine the effects of mild airflow limitation on K-complex frequency and morphology and electroencephalogram (EEG) spectral power. Transient reductions in continuous positive airway pressure (CPAP) during stable N2 sleep were performed to induce mild airflow limitation in 20 patients with obstructive sleep apnea (OSA) and 10 healthy controls aged 44 ± 13 y. EEG at C3 and airflow were measured in 1-min windows to quantify K-complex properties and EEG spectral power immediately before and during transient reductions in CPAP. The frequency and morphology (amplitude and latency of P200, N550 and N900 components) of K-complexes and EEG spectral power were compared between conditions. During mild airflow limitation (18% reduction in peak inspiratory airflow from baseline, 0.38 ± 0.11 versus 0.31 ± 0.1 L/sec) insufficient to cause American Academy of Sleep Medicine-defined cortical arousal, K-complex frequency (9.5 ± 4.5 versus 13.7 ± 6.4 per min, P < 0.01), N550 amplitude (25 ± 3 versus 27 ± 3 μV, P < 0.01) and EEG spectral power (delta: 147 ± 48 versus 230 ± 99 μV(2), P < 0.01 and theta bands: 31 ± 14 versus 34 ± 13 μV(2), P < 0.01) significantly increased whereas beta band power decreased (14 ± 5 versus 11 ± 4 μV(2), P < 0.01) compared to the preceding non flow-limited period on CPAP. K-complex frequency, morphology, and timing did not differ between patients and controls. Mild airflow limitation increases K-complex frequency, N550 amplitude, and spectral power of delta and theta bands. In addition to providing mechanistic insight into the role of mild airflow limitation on K-complex characteristics and EEG activity, these findings may have important implications for respiratory conditions in which airflow limitation during sleep is common (e.g., snoring and OSA). © 2016 Associated Professional Sleep Societies, LLC.

It's a word: early electrophysiological response to the character likeness of pictographs.

PubMed

Zhang, Mingxia; Jiang, Ting; Mei, Leilei; Yang, Hongmin; Chen, Chuansheng; Xue, Gui; Dong, Qi

2011-07-01

Using unfamiliar and meaningless pictographs that varied in their degree of similarity to Chinese characters, the current study tested whether the early electrophysiological response was modulated by character likeness. We measured P100 and N170 while 20 native Chinese speakers were viewing Chinese characters, drawings of objects, and pictographs. Comparisons across the three categories of stimuli showed that pictographs elicited a smaller N170 amplitude than did Chinese characters and a stronger N170 amplitude than did objects, but did not differ in the P100 amplitude from the other two categories. Within the category of pictographs, stimuli with a higher degree of character likeness elicited larger N170 amplitudes and shorter N170 peak latencies, and this effect was again not observed in P100. These results suggest that N170 is sensitive to visual stimuli's character likeness even though they are unfamiliar pictographs with no meanings or sounds. Copyright © 2010 Society for Psychophysiological Research.

Modulation of cosmic rays on geomagnetically most quiet days

NASA Astrophysics Data System (ADS)

Agarwal Mishra, Rekha; Agarwal Mishra, Rekha; Mishra, Rajesh Kumar

The aim of this work is to study the first three harmonics of cosmic ray intensity on geomagnetically quiet days over the period 1980-1990 for Deep River and Tokyo neutron monitoring stations. The amplitude of first harmonic remains high for Deep River having low cutoff rigidity as compared to Tokyo neutron monitor having high cutoff rigidity on quiet days.. The diurnal time of maximum significantly shifts to an earlier time as compared to the corotational/1800 Hr direction at both the stations having different cutoff rigidities. The time of maximum for first harmonic significantly shifts towards later hours and for second harmonic it shifts towards earlier hours at low cutoff rigidity station i.e. Deep River as compared to the high cut off rigidity station i.e. Tokyo on quiet days. The amplitude of semi/tri-diurnal anisotropy have a good positive correlation with solar wind velocity, while the others (i.e. amplitude and phase) have no significant correlation on quiet days for Deep River and Tokyo having different cutoff rigidity during 1980-1990. The solar wind velocity significantly remains in the range 350 to 425 km/s i.e. being nearly average on quiet days. The amplitude and direction of the anisotropy on quiet days are weakly dependent on high-speed solar wind streams for two neutron monitoring station of low and high cutoff rigidity threshold. The semi-diurnal amplitude has a significant anti-correlation, whereas the amplitude of third harmonic and direction of first harmonic has a good anti-correlation with IMF Bz and the product V x Bz on quiet days at Deep River station. However, the direction of first harmonic has a significant anti-correlation and the direction of second harmonic has a good anti-correlation with IMF Bz and the product V x Bz on quiet days at Tokyo station.

Recovery function of the human brain stem auditory-evoked potential.

PubMed

Kevanishvili, Z; Lagidze, Z

1979-01-01

Amplitude reduction and peak latency prolongation were observed in the human brain stem auditory-evoked potential (BEP) with preceding (conditioning) stimulation. At a conditioning interval (CI) of 5 ms the alteration of BEP was greater than at a CI of 10 ms. At a CI of 10 ms the amplitudes of some BEP components (e.g. waves I and II) were more decreased than those of others (e.g. wave V), while the peak latency prolongation did not show any obvious component selectivity. At a CI of 5 ms, the extent of the amplitude decrement of individual BEP components differed less, while the increase in the peak latencies of the later components was greater than that of the earlier components. The alterations of the parameters of the test BEPs at both CIs are ascribed to the desynchronization of intrinsic neural events. The differential amplitude reduction at a CI of 10 ms is explained by the different durations of neural firings determining various effects of desynchronization upon the amplitudes of individual BEP components. The decrease in the extent of the component selectivity and the preferential increase in the peak latencies of the later BEP components observed at a CI of 5 ms are explained by the intensification of the mechanism of the relative refractory period.

EEG and ERP profiles in the high alcohol preferring (HAP) and low alcohol preferring (LAP) mice: relationship to ethanol preference.

PubMed

Slawecki, Craig J; Grahame, Nicholas J; Roth, Jennifer; Katner, Simon N; Ehlers, C L

2003-01-31

Neurophysiological measures, such as decreased P300 amplitude and altered EEG alpha activity, have been associated with increased alcoholism risk. The purpose of the present study was to extend the assessment of the neurophysiological indices associated with alcohol consumption to a recently developed mouse model of high ethanol consumption, the first replicate line of high alcohol preferring (HAP-1) and low alcohol preferring (LAP-1) mice. Male HAP-1, LAP-1, and HS mice from the Institute for Behavioral Genetics at the University of Colorado Health Science Center (i.e., HS/Ibg mice) were implanted with cortical electrodes. EEG activity, and event related potentials (ERPs) were then examined. Following electrophysiological assessment, ethanol preference was assessed to examine the relationship between neurophysiological indices and ethanol consumption. EEG analyses revealed that HAPs and HS/Ibgs had greater peak frequency in the 2-4-Hz band and lower peak frequency in the 6-8- and 1-50-Hz bands of the cortical EEG compared to LAPs. Compared to HAPs, LAPs and HS/Ibgs had decreased peak EEG frequency in the 8-16-Hz band. Decreased parietal cortical power from 8 to 50 Hz was associated with high initial ethanol preference in HAP mice. In regards to ERPs, P1 amplitude was greater in HAPs compared to both LAPs and HS/Ibgs and the P3 latency in LAPs was decreased compared to both HAPs and HS/Ibgs. As expected, HAPs consumed more ethanol and had higher ethanol preference than LAPs and HS/Ibgs. There were no significant differences in ethanol intake or preference between HS/Ibgs and LAPs. These data indicate that selective breeding of the HAP and LAP lines has resulted in the divergence of EEG and ERP phenotypes. The differences observed suggest that increased cortical P1 amplitude and altered cortical EEG activity in the 8-50-Hz frequency range may be neurophysiological 'risk factors' associated with high ethanol consumption in mice. Decreased P3 latency in LAPs compared to HAPs and HS/Ibgs mice may be a 'protective factor'.

Effects of stop-signal probability in the stop-signal paradigm: the N2/P3 complex further validated.

PubMed

Ramautar, J R; Kok, A; Ridderinkhof, K R

2004-11-01

The aim of this study was to examine the effects of frequency of occurrence of stop signals in the stop-signal paradigm. Presenting stop signals less frequently resulted in faster reaction times to the go stimulus and a lower probability of inhibition. Also, go stimuli elicited larger and somewhat earlier P3 responses when stop signals occurred less frequently. Since the amplitude effect was more pronounced on trials when go signals were followed by fast than slow reactions, it probably reflected a stronger set to produce fast responses. N2 and P3 components to stop signals were observed to be larger and of longer latency when stop signals occurred less frequently. The amplitude enhancement of these N2 and P3 components were more pronounced for unsuccessful than for successful stop-signal trials. Moreover, the successfully inhibited stop trials elicited a frontocentral P3 whereas unsuccessfully inhibited stop trials elicited a more posterior P3 that resembled the classical P3b. P3 amplitude in the unsuccessfully inhibited condition also differed between waveforms synchronized with the stop signal and waveforms synchronized with response onset whereas N2 amplitude did not. Taken together these findings suggest that N2 reflected a greater significance of failed inhibitions after low probability stop signals while P3 reflected continued processing of the erroneous response after response execution.

Changes in event-related potentials in patients with first-episode schizophrenia and their siblings.

PubMed

Yang, Chengqing; Zhang, Tianhong; Li, Zezhi; Heeramun-Aubeeluck, Anisha; Liu, Na; Huang, Nan; Zhang, Jie; He, Leiying; Li, Hui; Tang, Yingying; Chen, Fazhan; Wang, Jijun; Lu, Zheng

2017-01-17

This study aimed to explore the characteristics of event-related potentials induced by facial emotion recognition in patients with first-episode schizophrenia and in their siblings. In this case-control study, 30 first-episode schizophrenia patients, 26 siblings, and 30 healthy controls were enrolled. They completed facial emotion recognition tasks from the Ekman Standard Faces Database as an induction for evoked potentials. Evoked potential data were obtained using a 64-channel electroencephalography system. Average evoked potential waveforms were computed from epochs for each stimulus type. The amplitudes and latency of the event-related potentials for P100 (positive potential 100 ms after stimulus onset), N170 (negative potential 170 ms after stimulus onset), and N250 (fronto-central peak) were investigated at O1, O2, P7, and P8 electrode locations. There were significant differences between the groups for P100 amplitude (F = 11.526, P < 0.001), electrode position (F = 450.592, P < 0.001), emotion (disgust vs. happiness vs. fear) (F = 1722.467, P < 0.001), and emotion intensity (low vs. moderate vs. high) (F = 1737.169, P < 0.001). Post hoc analysis showed significantly larger amplitudes in the schizophrenia group at the O1, O2, P7, and P8 electrode positions. There were no significant differences between the siblings of schizophrenia patients and the healthy controls. Patients with schizophrenia showed abnormalities in P100 amplitude, but similar results were not observed in their siblings. These results provide evidence of dysfunctional event-related potential patterns underlying facial emotion processing in patients with schizophrenia. P100 may be a characteristic index of schizophrenia.

Do Rare Stimuli Evoke Large P3s by Being Unexpected? A Comparison of Oddball Effects Between Standard-Oddball and Prediction-Oddball Tasks

PubMed Central

Verleger, Rolf; Śmigasiewicz, Kamila

2016-01-01

The P3 component of event-related potentials increases when stimuli are rarely presented. It has been assumed that this oddball effect (rare-frequent difference) reflects the unexpectedness of rare stimuli. The assumption of unexpectedness and its link to P3 amplitude were tested here. A standard- oddball task requiring alternative key-press responses to frequent and rare stimuli was compared with an oddball-prediction task where stimuli had to be first predicted and then confirmed by key-pressing. Oddball effects in the prediction task depended on whether the frequent or the rare stimulus had been predicted. Oddball effects on P3 amplitudes and error rates in the standard oddball task closely resembled effects after frequent predictions. This corroborates the notion that these effects occur because frequent stimuli are expected and rare stimuli are unexpected. However, a closer look at the prediction task put this notion into doubt because the modifications of oddball effects on P3 by expectancies were entirely due to effects on frequent stimuli, whereas the large P3 amplitudes evoked by rare stimuli were insensitive to predictions (unlike response times and error rates). Therefore, rare stimuli cannot be said to evoke large P3 amplitudes because they are unexpected. We discuss these diverging effects of frequency and expectancy, as well as general differences between tasks, with respect to concepts and hypotheses about P3b’s function and conclude that each discussed concept or hypothesis encounters some problems, with a conception in terms of subjective relevance assigned to stimuli offering the most consistent account of these basic effects. PMID:27512527

[Auditory evoked potential and personality traits in chronic primary insomniacs].

PubMed

Shen, Jian; Shui, Ren-de; Feng, Lei; Liu, Yu-Hong; He, Wei; Huang, Jing-Yi; Wang, Wei

2009-05-01

To investigate the personality traits and intensity dependence of auditory evoked potentials (AEPs) in chronic primary insomnia. Thirty-seven patients with chronic primary insomnia (insomnia group) and 44 healthy subjects (control group) were enrolled in the study. The AEPs were examined in insomnia and control groups; the personality traits were studied by Zuckerman's Sensation Seeking Scales (SSS) and Zuckerman-Kuhlman's Personality Questionnaire (ZKPQ); and the mood states by Plutchik-van Praag's Depression Inventory (PVP). The scores of neuroticism-anxiety and depression in insomnia group were significantly higher than those in control group (P<0.01); and the scores of impulsivity and aggression-hostility were also higher than those in control group (P<0.05); N1-P2 amplitude of AEP increased with stimulus intensity, which were significantly different in 70, 80, 90,100 dB (P<0.01). There were significant correlations between activity and N1 latency at 80 dB, activity and P2 latency at 100 dB (r=0.270, r=0.276, P<0.05); and between total scores of sensation seeking scale and N1-P2 amplitude (r=0.3746, r=0.35329, P<0.01) at 70 and 90 dB stimulus intensity in insomnia group. There were significant correlations among experience seeking and N1-P2 amplitude, experience seeking and slope rate (P<0.01) at 70, 80, 90, 100 dB stimulus intensity in insomnia group (r=0.539, r=0.3439, r=0.439, r=0.3278). There were significant correlations between sensation seeking of boredom susceptibility and slope rate (r=-0.282998, P<0.05) in insomnia group. There were significant correlations between thrill and adventure seeking and N1-P2 amplitude(r=0.2789, P<0.05) at 90 dB stimulus intensity in insomnia group; there were significant correlations between PVP and N1-P2 amplitude (r=-0.3434, r=-0.3158, P<0.05) at 70 dB and N1 latency at 80 dB in insomnia group. Chronic primary insomnia sufferers have higher levels of neuroticism-anxiety, depression, aggression-hostility and impulsivity, and some are correlated with stimulus intensity dependence in AEP.

Increasing measurement accuracy of age-related BOLD signal change: Minimizing vascular contributions by resting-state-fluctuation-of-amplitude scaling

PubMed Central

Kannurpatti, Sridhar S.; Motes, Michael A.; Rypma, Bart; Biswal, Bharat B.

2012-01-01

In this report we demonstrate a hemodynamic scaling method with resting-state fluctuation of amplitude (RSFA) in healthy adult younger and older subject groups. We show that RSFA correlated with breath hold (BH) responses throughout the brain in groups of younger and older subjects, that RSFA and BH performed comparably in accounting for age-related hemodynamic coupling changes, and yielded more veridical estimates of age-related differences in task-related neural activity. BOLD data from younger and older adults performing motor and cognitive tasks were scaled using RSFA and BH related signal changes. Scaling with RSFA and BH reduced the skew of the BOLD response amplitude distribution in each subject and reduced mean BOLD amplitude and variability in both age groups. Statistically significant differences in intra-subject amplitude variation across regions of activated cortex, and inter-subject amplitude variation in regions of activated cortex were observed between younger and older subject groups. Intra- and inter-subject variability differences were mitigated after scaling. RSFA, though similar to BH in minimizing skew in the un-scaled BOLD amplitude distribution, attenuated the neural activity related BOLD amplitude significantly less than BH. The amplitude and spatial extent of group activation were lower in the older than in the younger group prior to and after scaling. After accounting for vascular variability differences through scaling, age-related decreases in activation volume were observed during the motor and cognitive tasks. The results suggest that RSFA-scaled data yield age-related neural activity differences during task performance with negligible effects from non-neural (i.e., vascular) sources. PMID:20665721

Visually Evoked Potentials after Panretinal Photocoagulation in Omani Patients with Uncontrolled Diabetes Mellitus

PubMed Central

Shenoy, Radha; Al-Belushi, Habiba; Al-Ajmi, Sadiqa; Al-Nabhani, Susan Margaret; Ganguly, Shyam Sunder; Bialasiewicz, Alexander A.

2008-01-01

Aim: To report on the changes of latency and amplitudes of the pattern VEP in patients with uncontrolled diabetes mellitus II and I before and after panretinal laser treatment. Design: Single center hospital based comparative study. Methods: One hundred eyes of patients with proliferative diabetic vitreoretinopathy, and HbA1C ≥ 10 percent were subjected to Pattern Visually Evoked Potentials (Medtronic keyopint system, Nicolet) prior to and 4 weeks after PRP. Results were compared to age-matched non-diabetic controls. Chi-Square test, and paired ‘t’ test were used for statistical analysis. Results: Preoperative mean VEP amplitude was 8.35mV±3.71, and not significantly different to the control group (mean 10.51mV±3.34) (chi square test p=1). Mean preoperative P100 latency was 106.93±7.90ms and significantly different to the control group (103.21±7.65ms) (paired t-test p=0.001). After laser treatment, VEP amplitudes decreased in 48/100 eyes (mean total 5.11mV±2.4), and P100 latency increased in 75/100 eyes (mean total 110.47±7.35ms). Conclusion: In this study, PRP was followed by a significant decrease in VEP amplitudes in 48 percent and increase in latency in 75 percent of eyes. PMID:21346837

The analysis on the characteristics of North Korea 6th nuclear test, collapse and induced earthquakes

NASA Astrophysics Data System (ADS)

Park, J. H.; Park, Y. K.; Kim, T. S.; Kim, G.; Cho, C.; Kim, I.

2017-12-01

North Korea(NK) has conducted the 6th Underground Nuclear Test(UNT) with the one order bigger magnitude than previous ones on 3 Sep. 2017. By using correlated waveform comparison the estimated epicenter of the 6th NK UNT was estimated at 41.3020N 129.0795E located about 200 m toward northern direction from the previous 5th NK UNT site. The body wave magnitude was calculated as mb 5.7 through our routine process measuring the maximum amplitude of P wave in the higher frequency over 1 Hz using stations around the Korean peninsula, however, this could be underestimated in the case that the source energy spectra of UNT radiated dominantly in the lower frequency below 1 Hz. Considering source spectra of the 6th NK UNT, we applied to P wave the 2nd order Butterworth bandpass filter between 0.1 and 1 Hz and measured that the amplitude ratio of 6th/5th UNT. Instead of 6 7 ratio from the raw P waves, the filtered amplitude ratio resulted in 10 12 at several stations. After cross check of the amplitude ratio in bandpass filtered method to the previous NK UNT we finalized the magnitude of the 6th NK UNT as mb 6.1. The collapse earthquake has happened after the 6th NK UNT about 8 minutes 32 seconds and the epicenter estimated to be located around the UNT site within 1 km. The similarity of wave forms to that of the two mine collapse cases in South Korea and moment tensor inversion indicated the source mechanism was very similar to the mine collapse. Three earthquakes were detected and analyzed locations and magnitudes, we thought these earthquakes were induced from the accumulated tectonic stress by the NK UNT. The collapse event's wave forms are very different from those of the induced earthquakes.

Influence of fluid and volume state on PaO2 oscillations in mechanically ventilated pigs.

PubMed

Bodenstein, Marc; Bierschock, Stephan; Boehme, Stefan; Wang, Hemei; Vogt, Andreas; Kwiecien, Robert; David, Matthias; Markstaller, Klaus

2013-03-01

Varying pulmonary shunt fractions during the respiratory cycle cause oxygen oscillations during mechanical ventilation. In artificially damaged lungs, cyclical recruitment of atelectasis is responsible for varying shunt according to published evidence. We introduce a complimentary hypothesis that cyclically varying shunt in healthy lungs is caused by cyclical redistribution of pulmonary perfusion. Administration of crystalloid or colloid infusions would decrease oxygen oscillations if our hypothesis was right. Therefore, n=14 mechanically ventilated healthy pigs were investigated in 2 groups: crystalloid (fluid) versus no-fluid administration. Additional volume interventions (colloid infusion, blood withdrawal) were carried out in each pig. Intra-aortal PaO2 oscillations were recorded using fluorescence quenching technique. Phase shift of oxygen oscillations during altered inspiratory to expiratory (I:E) ventilation ratio and electrical impedance tomography (EIT) served as control methods to exclude that recruitment of atelectasis is responsible for oxygen oscillations. In hypovolemia relevant oxygen oscillations could be recorded. Fluid and volume state changed PaO2 oscillations according to our hypothesis. Fluid administration led to a mean decline of 105.3 mmHg of the PaO2 oscillations amplitude (P<0.001). The difference of the amplitudes between colloid administration and blood withdrawal was 62.4 mmHg in pigs not having received fluids (P=0.0059). Fluid and volume state also changed the oscillation phase during altered I:E ratio. EIT excluded changes of regional ventilation (i.e., recruitment of atelectasis) to be responsible for these oscillations. In healthy pigs, cyclical redistribution of pulmonary perfusion can explain the size of respiratory-dependent PaO2 oscillations.

Amplitude variations in the sdBV star PG 1605+072: Another beating time scale?

NASA Astrophysics Data System (ADS)

Pereira, T. M. D.; Lopes, I. P.

2004-10-01

PG 1605+072 has an unique and complex oscillation spectrum amongst the pulsating members of the EC 14026 stars. It has the longest periods and the richest, most puzzling frequency spectrum. We present a quantitative analysis of the photometric time-series obtained at 1-m telescope of the South African Astronomical Observatory. Thirteen oscillation parameters, frequencies, amplitudes and initial phases were determined from a 45 h time-series. Our work confirm previous observational results. The observed frequencies are within a difference smaller than 2.7% of the theoretical values, and less than 0.1% of other previous studies. We also infer the existence of variation of a periodicity of 4-5 days on the amplitude of the observed modes, similar to the yearly time-scale variation found by previous studies. Furthermore, we found a new frequency of 2133 μ Hz which has not been previously reported, its origin being yet unclear. Based on observations obtained at the South African Astronomical Observatory (SAAO). This research was supported by a grant from Fundação da Ciência e Tecnologia, grant No. PESO/P/PRO/40142/2000.

Development of auditory event-related potentials in infants prenatally exposed to methadone.

PubMed

Paul, Jonathan A; Logan, Beth A; Krishnan, Ramesh; Heller, Nicole A; Morrison, Deborah G; Pritham, Ursula A; Tisher, Paul W; Troese, Marcia; Brown, Mark S; Hayes, Marie J

2014-07-01

Developmental features of the P2 auditory ERP in a change detection paradigm were examined in infants prenatally exposed to methadone. Opiate dependent pregnant women maintained on methadone replacement therapy were recruited during pregnancy (N = 60). Current and historical alcohol and substance use, SES, and psychiatric status were assessed with a maternal interview during the third trimester. Medical records were used to collect information regarding maternal medications, monthly urinalysis, and breathalyzer to confirm comorbid drug and alcohol exposures. Between birth and 4 months infant ERP change detection performance was evaluated on one occasion with the oddball paradigm (.2 probability oddball) using pure-tone stimuli (standard = 1 kHz and oddball = 2 kHz frequency) at midline electrode sites, Fz, Cz, Pz. Infant groups were examined in the following developmental windows: 4-15, 16-32, or 33-120 days PNA. Older groups showed increased P2 amplitude at Fz and effective change detection performance at P2 not seen in the newborn group. Developmental maturation of amplitude and stimulus discrimination for P2 has been reported in developing infants at all of the ages tested and data reported here in the older infants are consistent with typical development. However, it has been previously reported that the P2 amplitude difference is detectable in neonates; therefore, absence of a difference in P2 amplitude between stimuli in the 4-15 days group may represent impaired ERP performance by neonatal abstinence syndrome or prenatal methadone exposure. © 2013 Wiley Periodicals, Inc.

Auditory event-related potentials in methadone substituted opiate users.

PubMed

Wang, Grace Y; Kydd, Robert; Russell, Bruce R

2015-09-01

The effects of methadone maintenance treatment (MMT) on neurophysiological function are unclear. Using an auditory oddball paradigm, event-related potential (ERP) amplitudes and latencies were measured in 32 patients undertaking MMT, 17 opiate users who were addicted but not receiving substitution treatment and 25 healthy control subjects. Compared with healthy control subjects, the MMT and opiate user groups showed an increased P200 amplitude in response to target stimuli. The opiate user group also exhibited a decreased amplitude and an increased latency of N200, and a greater number of task-related errors than either healthy control subjects or patients undertaking MMT. There were no significant group differences in the P300 amplitude. However, it is noteworthy that the frontal P300 amplitude of the MMT group was greater than that of opiate users or healthy controls. Our findings suggest that altered sensory information processing associated with a history of opiate use remains in patients undertaking MMT. However, there are less marked ERP abnormalities in those receiving MMT than in active opiate users. The deficits in information processing associated with illicit opiate use are likely to be reduced during MMT. © The Author(s) 2015.

Effects of stimulus intensity on frontal, central and parietal somatosensory evoked potentials after median nerve stimulation.

PubMed

Huttunen, J

1995-01-01

Effects of the intensity of electrical median nerve stimulation were previously reported for the subcortical and first cortical somatosensory evoked potentials (SEPs) but not for later cortical waves whose applications in neurology have gained growing interest in recent years. This paper therefore describes the stimulus intensity effects on frontal, central and parietal SEP waveforms up to 90 msec after stimulus. The intensities were 1.5 and 2 times sensory threshold (ST), motor threshold (MT), and 1.5 and 2 times MT. Between 1.5 x ST and MT all SEP components grew in amplitude, except N60 which was essentially saturated already at 1.5 x ST. The growth was most marked for P14 and N20 whereas later potentials changed less, i.e. the slopes of the intensity-amplitude curves progressively flattened with increasing latency of SEP component. Between MT and 2 x MT no significant further alterations occurred in the early cortical potentials up to 30 msec. However, subtle changes occurred in the P40-N60 waveforms and subtraction of responses revealed a small centroparietal P35-N45 difference wave elicited only by high-intensity (2 x MT) stimulation. It is concluded that for practical purposes stimulation slightly above MT yields maximum cortical SEPs. The results are not generally compatible with the proposition that P40 and N60 are conveyed by higher threshold, small-diameter afferent fibers compared with N20. However, the P35-N45 difference wave at 2 x MT indicates that small-diameter afferent components may be embedded in the waveforms obtained at high intensity.

Sex differences in emotional contexts modulation on response inhibition.

PubMed

Ramos-Loyo, Julieta; Angulo-Chavira, Armando; Llamas-Alonso, Luis A; González-Garrido, Andrés A

2016-10-01

The aim of the present study was to explore sex differences in the effects that emotional contexts exert on the temporal course of response inhibition using event-related potentials (ERP). Participants performed a Go-NoGo response inhibition task under 3 context conditions: with 1) neutral background stimuli, and 2) pleasant, and 3) unpleasant emotional contexts. No sex differences were found in relation to accuracy. Women showed higher N2NoGo amplitudes than men in both emotional contexts; whereas during inhibition men tended to show higher P3NoGo amplitudes than women in the unpleasant context. Both groups experienced a relevant effect of the presence of the unpleasant context during inhibition processing, as shown by the enhancement of the N2NoGo amplitudes in frontal regions compared to results from the neutral and pleasant conditions. In addition, women showed differences between the pleasant and unpleasant contexts, with the latter inducing higher amplitude values. Only in men did inhibition accuracy correlate with higher N2NoGo and lower P3NoGo amplitudes in the emotional context conditions. These findings suggest that when an inhibition task is performed in an emotionally-neutral background context no sex differences are observed in either accuracy or ERP components. However, when the emotional context was introduced -especially the unpleasant one- some gender differences did become evident. The higher N2NoGo amplitude at the presence of the unpleasant context may reflect an effect on attention and conflict monitoring. In addition, results suggest that during earlier processing stages, women invested more resources to process inhibition than men. Furthermore, men who invested more neural resources during earlier stages showed better response inhibition than those who did it during later processing stages, more closely-related to cognitive and motor inhibition processes. Copyright © 2016 Elsevier Ltd. All rights reserved.

Effect of Velocity of Detonation of Explosives on Seismic Radiation

NASA Astrophysics Data System (ADS)

Stroujkova, A. F.; Leidig, M.; Bonner, J. L.

2014-12-01

We studied seismic body wave generation from four fully contained explosions of approximately the same yields (68 kg of TNT equivalent) conducted in anisotropic granite in Barre, VT. The explosions were detonated using three types of explosives with different velocities of detonation (VOD): Black Powder (BP), Ammonium Nitrate Fuel Oil/Emulsion (ANFO), and Composition B (COMP B). The main objective of the experiment was to study differences in seismic wave generation among different types of explosives, and to determine the mechanism responsible for these differences. The explosives with slow burn rate (BP) produced lower P-wave amplitude and lower corner frequency, which resulted in lower seismic efficiency (0.35%) in comparison with high burn rate explosives (2.2% for ANFO and 3% for COMP B). The seismic efficiency estimates for ANFO and COMP B agree with previous studies for nuclear explosions in granite. The body wave radiation pattern is consistent with an isotropic explosion with an added azimuthal component caused by vertical tensile fractures oriented along pre-existing micro-fracturing in the granite, although the complexities in the P- and S-wave radiation patterns suggest that more than one fracture orientation could be responsible for their generation. High S/P amplitude ratios and low P-wave amplitudes suggest that a significant fraction of the BP source mechanism can be explained by opening of the tensile fractures as a result of the slow energy release.

Ontogeny of vestibular compound action potentials in the domestic chicken

NASA Technical Reports Server (NTRS)

Jones, S. M.; Jones, T. A.

2000-01-01

Compound action potentials of the vestibular nerve were measured from the surface of the scalp in 148 chickens (Gallus domesticus). Ages ranged from incubation day 18 (E18) to 22 days posthatch (P22). Responses were elicited using linear acceleration cranial pulses. Response thresholds decreased at an average rate of -0.45 dB/day. The decrease was best fit by an exponential model with half-maturity time constant of 5.1 days and asymptote of approximately -25.9 dB re:1.0 g/ms. Mean threshold approached within 3 dB of the asymptote by ages P6-P9. Similarly, response latencies decreased exponentially to within 3% of mature values at ages beyond P9. The half-maturity time constant for peripheral response peak latencies P1, N1, and P2 was comparable to thresholds and ranged from approximately 4.6 to 6.2 days, whereas central peaks (N2, P3, and N3) ranged from 2.9 to 3.4 days. Latency-intensity slopes for P1, N1, and P2 tended to decrease with age, reaching mature values within approximately 100 hours of hatching. Amplitudes increased as a function of age with average growth rates for response peaks ranging from 0.04 to 0.09 microV/day. There was no obvious asymptote to the growth of amplitudes over the ages studied. Amplitude-intensity slopes also increased modestly with age. The results show that gravity receptors are responsive to transient cranial stimuli as early as E19 in the chicken embryo. The functional response of gravity receptors continues to develop for many days after all major morphological structures are in place. Distinct maturational processes can be identified in central and peripheral neural relays. Functional improvements during maturation may result from refinements in the receptor epithelia, improvements in central and peripheral synaptic transmission, increased neural myelination, as well as changes in the mechanical coupling between the cranium and receptor organ.

Ontogeny of Vestibular Compound Action Potentials in the Domestic Chicken

PubMed Central

M. Jones, Sherri

2000-01-01

Compound action potentials of the vestibular nerve were measured from the surface of the scalp in 148 chickens (Gallus domesticus). Ages ranged from incubation day 18 (E18) to 22 days posthatch (P22). Responses were elicited using linear acceleration cranial pulses. Response thresholds decreased at an average rate of –0.45 dB/day. The decrease was best fit by an exponential model with half-maturity time constant of 5.1 days and asymptote of approximately –25.9 dB re:1.0 g/ms. Mean threshold approached within 3 dB of the asymptote by ages P6–P9. Similarly, response latencies decreased exponentially to within 3% of mature values at ages beyond P9. The half-maturity time constant for peripheral response peak latencies P1, N1, and P2 was comparable to thresholds and ranged from approximately 4.6 to 6.2 days, whereas central peaks (N2, P3, and N3) ranged from 2.9 to 3.4 days. Latency-intensity slopes for P1, N1, and P2 tended to decrease with age, reaching mature values within approximately 100 hours of hatching. Amplitudes increased as a function of age with average growth rates for response peaks ranging from 0.04 to 0.09 μV/day. There was no obvious asymptote to the growth of amplitudes over the ages studied. Amplitude-intensity slopes also increased modestly with age. The results show that gravity receptors are responsive to transient cranial stimuli as early as E19 in the chicken embryo. The functional response of gravity receptors continues to develop for many days after all major morphological structures are in place. Distinct maturational processes can be identified in central and peripheral neural relays. Functional improvements during maturation may result from refinements in the receptor epithelia, improvements in central and peripheral synaptic transmission, increased neural myelination, as well as changes in the mechanical coupling between the cranium and receptor organ. PMID:11545229

Individual Differences in Auditory Brainstem Response Wave Characteristics

PubMed Central

Jagadeesh, Anoop; Mauermann, Manfred; Ernst, Frauke

2016-01-01

Little is known about how outer hair cell loss interacts with noise-induced and age-related auditory nerve degradation (i.e., cochlear synaptopathy) to affect auditory brainstem response (ABR) wave characteristics. Given that listeners with impaired audiograms likely suffer from mixtures of these hearing deficits and that ABR amplitudes have successfully been used to isolate synaptopathy in listeners with normal audiograms, an improved understanding of how different hearing pathologies affect the ABR source generators will improve their sensitivity in hearing diagnostics. We employed a functional model for human ABRs in which different combinations of hearing deficits were simulated and show that high-frequency cochlear gain loss steepens the slope of the ABR Wave-V latency versus intensity and amplitude versus intensity curves. We propose that grouping listeners according to a ratio of these slope metrics (i.e., the ABR growth ratio) might offer a way to factor out the outer hair cell loss deficit and maximally relate individual differences for constant ratios to other peripheral hearing deficits such as cochlear synaptopathy. We compared the model predictions to recorded click-ABRs from 30 participants with normal or high-frequency sloping audiograms and confirm the predicted relationship between the ABR latency growth curve and audiogram slope. Experimental ABR amplitude growth showed large individual differences and was compared with the Wave-I amplitude, Wave-V/I ratio, or the interwaveI–W latency in the same listeners. The model simulations along with the ABR recordings suggest that a hearing loss profile depicting the ABR growth ratio versus the Wave-I amplitude or Wave-V/I ratio might be able to differentiate outer hair cell deficits from cochlear synaptopathy in listeners with mixed pathologies. PMID:27837052

Different fatigue-resistant leg muscles and EMG response during whole-body vibration.

PubMed

Simsek, Deniz

2017-12-01

The purpose of this study was to determine the effects of static whole-body vibration (WBV) on the Electromyograhic (EMG) responses of leg muscles, which are fatigue-resistant in different manner. The study population was divided into two groups according to the values obtained by the Fatigue Index [Group I: Less Fatigue Resistant (LFR), n=11; Group II: More Fatigue Resistant (MFR), n=11]. The repeated electromyographic (EMG) activities of four leg muscles were analyzed the following determinants: (1) frequency (30 Hz, 35 Hz and 40 Hz); (2) stance position (static squat position); (3) amplitude (2 mm and 4 mm) and (4) knee flexion angle (120°), (5) vertical vibration platform. Vibration data were analyzed using Minitab 16 (Minitab Ltd, State College, PA, USA). The significance level was set at p<.05. The study results showed that static WBV stimuli given at different frequencies and amplitudes resulted in a significant increase (p<.05) in compared, the LFR group showed significantly (1) higher rates of quadriceps femoris and hamstring muscle fatigue (p<.05), (2) higher levels of knee extensor and flexor torque (p<.05) and (3) higher percentage increases in EMG activation at higher frequencies (max at 40 Hz) and amplitudes (4 mm) (p<.05). The present study can be used for the optimal prescription of vibration exercise and can serve to guide the development of training programs. Copyright © 2017 Elsevier Ltd. All rights reserved.

Moral-up first, immoral-down last: the time course of moral metaphors on a vertical dimension.

PubMed

Wang, Han Lin; Lu, Ya Qiao; Lu, Zhong Yi

2016-03-02

Many abstract bipolar concepts are usually represented by metaphors on vertical dimensions (e.g. positive-up, negative-down). However, several studies have found an asymmetry in the way in which individuals process bipolar dimensions, with +polarities being stronger than -polarities. The current research focused on moral metaphors on a vertical dimension (e.g. moral-up and immoral-down) and examined the asymmetric representation of moral and immoral concepts. The first experiment showed a distinct metaphorical association between morality and vertical space, consistent with earlier research. The second experiment showed that moral and immoral words are processed differently depending on whether they are used as metaphorically congruent or incongruent vertical cues. 'Moral-up' association modulated the amplitudes of the N1, P2, and late positive-going potential during the processing of moral words, whereas the 'immoral-down' association only modulated the amplitudes of the late positive-going potential induced during the processing of immoral words. These results suggest that asymmetry in the processing of vertically represented morality metaphors is reflected in the time course of the representation of these bipolar concepts, with the 'moral-up' association having an earlier effect than the 'immoral-down' association.

Exclusive photoproduction of J/ψ and ψ(2S) in pp and AA collisions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cisek, Anna; Schäfer, Wolfgang; Szczurek, Antoni

2015-04-10

The amplitude for γp → J/ψp(γp → ψ'p) is calculated in a pQCD k{sub ⊥}-factorization approach. The total cross section for this process is calculated for different unintegrated gluon distributions and compared with the HERA data and the data extracted recently by the LHCb collaboration. The amplitude for γp → J/ψp(γp → ψ'p) is used to predict the cross section for exclusive photoproduction of the J/ψ(ψ') meson in proton-proton and nucleus-nucleus collisions. In the pp case, compared to earlier calculations we include both Dirac and Pauli electromagnetic form factors. We also discuss the dependence of nuclear shadowing on the charmoniummore » state.« less

[The effect of enzymatic treatment using proteases on properties of persistent sodium current in CA1 pyramidal neurons of rat hippocampus].

PubMed

Lun'ko, O O; Isaiev, D S; Maxymiuk, O P; Kryshtal', O O; Isaieva, O V

2014-01-01

We investigated the effect of proteases, widely used for neuron isolation in electrophysiological studies, on the amplitude and kinetic characteristics of persistent sodium current (I(NaP)) in hippocampal CA1 pyramidal neurons. Properties of I(NaP) were studied on neurons isolated by mechanical treatment (control group) and by mechanical and enzymatic treatment using pronase E (from Streptomyces griseus) or protease type XXIII (from Aspergillus oryzae). We show that in neurons isolated with pronase E kinetic of activation and density of I(NaP) was unaltered. Enzymatic treatment with protease type XXIII did not alter I(NaP) activation but result in significant decrease in I(NaP) density. Our data indicates that enzymatic treatment using pronase E for neuron isolation is preferable for investigation of I(NaP).

Exploring the effects of antisocial personality traits on brain potentials during face processing.

PubMed

Pfabigan, Daniela M; Alexopoulos, Johanna; Sailer, Uta

2012-01-01

Antisocial individuals are characterized to display self-determined and inconsiderate behavior during social interaction. Furthermore, recognition deficits regarding fearful facial expressions have been observed in antisocial populations. These observations give rise to the question whether or not antisocial behavioral tendencies are associated with deficits in basic processing of social cues. The present study investigated early visual stimulus processing of social stimuli in a group of healthy female individuals with antisocial behavioral tendencies compared to individuals without these tendencies while measuring event-related potentials (P1, N170). To this end, happy and angry faces served as feedback stimuli which were embedded in a gambling task. Results showed processing differences as early as 88-120 ms after feedback onset. Participants low on antisocial traits displayed larger P1 amplitudes than participants high on antisocial traits. No group differences emerged for N170 amplitudes. Attention allocation processes, individual arousal levels as well as face processing are discussed as possible causes of the observed group differences in P1 amplitudes. In summary, the current data suggest that sensory processing of facial stimuli is functionally intact but less ready to respond in healthy individuals with antisocial tendencies.

Influence of different attentional focus on EMG amplitude and contraction duration during the bench press at different speeds.

PubMed

Calatayud, Joaquin; Vinstrup, Jonas; Jakobsen, Markus D; Sundstrup, Emil; Colado, Juan Carlos; Andersen, Lars L

2018-05-01

The purpose of this study was to investigate whether using different focus affects electromyographic (EMG) amplitude and contraction duration during bench press performed at explosive and controlled speeds. Eighteen young male individuals were familiarized with the procedure and performed the one-maximum repetition (1RM) test in the first session. In the second session, participants performed the bench press exercise at 50% of the 1RM with 3 different attentional focuses (regular focus on moving the load vs contracting the pectoralis vs contracting the triceps) at 2 speed conditions (controlled vs maximal speed). During the controlled speed condition, focusing on using either the pectoralis or the triceps muscles increased pectoralis normalized EMG (nEMG) by 6% (95% CI 3-8%; p = 0.0001) and 4% nEMG (95% CI 1-7%; p = 0.0096), respectively, compared with the regular focus condition. Triceps activity was increased by 4% nEMG (95% CI 0-7%; p = 0.0308) at the controlled speed condition during the triceps focus. During the explosive speed condition, the use of different focuses had no effect. The different attentional focus resulted in comparable contraction duration for the measured muscles when the exercise was performed explosively. Using internal focus to increase EMG amplitude seems to function only during conditions of controlled speed.

Sustained attention in skilled and novice martial arts athletes: a study of event-related potentials and current sources.

PubMed

Sanchez-Lopez, Javier; Silva-Pereyra, Juan; Fernandez, Thalia

2016-01-01

Background. Research on sports has revealed that behavioral responses and event-related brain potentials (ERP) are better in expert than in novice athletes for sport-related tasks. Focused attention is essential for optimal athletic performance across different sports but mainly in combat disciplines. During combat, long periods of focused attention (i.e., sustained attention) are required for a good performance. Few investigations have reported effects of expertise on brain electrical activity and its neural generators during sport-unrelated attention tasks. The aim of the present study was to assess the effect of expertise (i.e., skilled and novice martial arts athletes) analyzing the ERP during a sustained attention task (Continuous Performance Task; CPT) and the cortical three-dimensional distribution of current density, using the sLORETA technique. Methods. CPT consisted in an oddball-type paradigm presentation of five stimuli (different pointing arrows) where only one of them (an arrow pointing up right) required a motor response (i.e., target). CPT was administered to skilled and novice martial arts athletes while EEG were recorded. Amplitude ERP data from target and non-target stimuli were compared between groups. Subsequently, current source analysis for each ERP component was performed on each subject. sLORETA images were compared by condition and group using Statistical Non-Parametric Mapping analysis. Results. Skilled athletes showed significant amplitude differences between target and non-target conditions in early ERP components (P100 and P200) as opposed to the novice group; however, skilled athletes showed no significant effect of condition in N200 but novices did show a significant effect. Current source analysis showed greater differences in activations in skilled compared with novice athletes between conditions in the frontal (mainly in the Superior Frontal Gyrus and Medial Frontal Gyrus) and limbic (mainly in the Anterior Cingulate Gyrus) lobes. Discussion. These results are supported by previous findings regarding activation of neural structures that underlie sustained attention. Our findings may indicate a better-controlled attention in skilled athletes, which suggests that expertise can improve effectiveness in allocation of attentional resources during the first stages of cognitive processing during combat.

Presynaptic and postsynaptic effects of the venom of the Australian tiger snake at the neuromuscular junction

PubMed Central

Datyner, M. E.; Gage, P. W.

1973-01-01

1. Crude venom (TSV) from the Australian tiger snake (Notechis scutatus scutatus) has both presynaptic and postsynaptic effects at the neuromuscular junctions of toads. 2. TSV (50 μg/ml) rapidly blocked indirectly elicited muscle twitches without affecting the compound action potential in the sciatic nerve or twitches elicited by direct stimulation. 3. Low concentrations of the venom (1-10 μg/ml) reduced the amplitude of miniature endplate potentials (m.e.p.ps) and inhibited the depolarization of muscle fibres normally caused by carbachol. It was concluded that a fraction of the venom binds to acetylcholine receptors. 4. The frequency of m.e.p.ps was at first increased by TSV at a concentration of 1 μg/ml. Occasional, high frequency `bursts' of m.e.p.ps were recorded in some preparations. The mean frequency of m.e.p.ps appeared to fall after several hours in the venom. 5. The quantal content of endplate potentials (e.p.ps) was reduced by the venom. With low concentrations (1 μg/ml), an initial increase in quantal content was often seen. When the quantal content was markedly depressed there was no parallel reduction in the amplitude of nerve terminal spikes recorded extracellularly, though a later fall in size and slowing of time course was often seen. 6. There was evidence that TSV eventually changed the normal Poisson characteristics of the spontaneous release of quanta and this may be correlated with electronmicroscopic changes in nerve terminals. 7. Tiger snake antivenene counteracted the postsynaptic, but not the presynaptic effects of TSV when they had developed. PMID:4367126

Auditory Evoked Potentials with Different Speech Stimuli: a Comparison and Standardization of Values

PubMed Central

Didoné, Dayane Domeneghini; Oppitz, Sheila Jacques; Folgearini, Jordana; Biaggio, Eliara Pinto Vieira; Garcia, Michele Vargas

2016-01-01

Introduction Long Latency Auditory Evoked Potentials (LLAEP) with speech sounds has been the subject of research, as these stimuli would be ideal to check individualś detection and discrimination. Objective The objective of this study is to compare and describe the values of latency and amplitude of cortical potentials for speech stimuli in adults with normal hearing. Methods The sample population included 30 normal hearing individuals aged between 18 and 32 years old with ontological disease and auditory processing. All participants underwent LLAEP search using pairs of speech stimuli (/ba/ x /ga/, /ba/ x /da/, and /ba/ x /di/. The authors studied the LLAEP using binaural stimuli at an intensity of 75dBNPS. In total, they used 300 stimuli were used (∼60 rare and 240 frequent) to obtain the LLAEP. Individuals received guidance to count the rare stimuli. The authors analyzed latencies of potential P1, N1, P2, N2, and P300, as well as the ampleness of P300. Results The mean age of the group was approximately 23 years. The averages of cortical potentials vary according to different speech stimuli. The N2 latency was greater for /ba/ x /di/ and P300 latency was greater for /ba/ x /ga/. Considering the overall average amplitude, it ranged from 5.35 and 7.35uV for different speech stimuli. Conclusion It was possible to obtain the values of latency and amplitude for different speech stimuli. Furthermore, the N2 component showed higher latency with the / ba / x / di / stimulus and P300 for /ba/ x / ga /. PMID:27096012

The determination of dark adaptation time using electroretinography in conscious Miniature Schnauzer dogs

PubMed Central

Yu, Hyung-Ah; Jeong, Man-Bok; Park, Shin-Ae; Kim, Won-Tae; Kim, Se-Eun; Chae, Je-Min; Yi, Na-Young

2007-01-01

The optimal dark adaptation time of electroretinograms (ERG's) performed on conscious dogs were determined using a commercially available ERG unit with a contact lens electrode and a built-in light source (LED-electrode). The ERG recordings were performed on nine healthy Miniature Schnauzer dogs. The bilateral ERG's at seven different dark adaptation times at an intensity of 2.5 cd·s/m2 was performed. Signal averaging (4 flashes of light stimuli) was adopted to reduce electrophysiologic noise. As the dark adaptation time increased, a significant increase in the mean a-wave amplitudes was observed in comparison to base-line levels up to 10 min (p < 0.05). Thereafter, no significant differences in amplitude occured over the dark adaptation time. Moreover, at this time the mean amplitude was 60.30 ± 18.47 µV. However, no significant changes were observed for the implicit times of the a-wave. The implicit times and amplitude of the b-wave increased significantly up to 20 min of dark adaptation (p < 0.05). Beyond this time, the mean b-wave amplitudes was 132.92 ± 17.79 µV. The results of the present study demonstrate that, the optimal dark adaptation time when performing ERG's, should be at least 20 min in conscious Miniature Schnauzer dogs. PMID:17993756

The determination of dark adaptation time using electroretinography in conscious miniature Schnauzer dogs.

PubMed

Yu, Hyung-Ah; Jeong, Man-Bok; Park, Shin-Ae; Kim, Won-Tae; Kim, Se-Eun; Chae, Je-Min; Yi, Na-Young; Seo, Kang-Moon

2007-12-01

The optimal dark adaptation time of electroretinograms (ERG's) performed on conscious dogs were determined using a commercially available ERG unit with a contact lens electrode and a built-in light source (LED-electrode). The ERG recordings were performed on nine healthy Miniature Schnauzer dogs. The bilateral ERG's at seven different dark adaptation times at an intensity of 2.5 cd.s/m(2) was performed. Signal averaging (4 flashes of light stimuli) was adopted to reduce electrophysiologic noise. As the dark adaptation time increased, a significant increase in the mean a-wave amplitudes was observed in comparison to base-line levels up to 10 min (p < 0.05). Thereafter, no significant differences in amplitude occurred over the dark adaptation time. Moreover, at this time the mean amplitude was 60.30 +/- 18.47 microV. However, no significant changes were observed for the implicit times of the a-wave. The implicit times and amplitude of the b-wave increased significantly up to 20 min of dark adaptation (p < 0.05). Beyond this time, the mean b-wave amplitudes was 132.92 +/- 17.79 microV. The results of the present study demonstrate that, the optimal dark adaptation time when performing ERG's, should be at least 20 min in conscious Miniature Schnauzer dogs.

Effects of muscle contraction on cervical vestibular evoked myogenic potentials in normal subjects.

PubMed

Rosengren, Sally M

2015-11-01

Cervical vestibular evoked myogenic potentials (cVEMPs) are vestibular-dependent muscle reflexes recorded from the sternocleidomastoid (SCM) muscles in humans. cVEMP amplitude is modulated by stimulus intensity and SCM muscle contraction strength, but the effect of muscle contraction is less well-documented. The effects of intensity and contraction were therefore compared in 25 normal subjects over a wide range of contractions. cVEMPs were recorded at different contraction levels while holding stimulus intensity constant and at different intensities while holding SCM contraction constant. The effect of muscle contraction on cVEMP amplitude was linear for most of the range of muscle contractions in the majority of subjects (mean R(2)=0.93), although there were some nonlinearities when the contraction was either very weak or very strong. Very weak contractions were associated with absent responses, incomplete morphology and prolonged p13 latencies. Normalization of amplitudes, by dividing the p13-n23 amplitude by the muscle contraction estimate, reduced the effect of muscle contraction, but tended to underestimate the amplitude with weak contractions. Minimum contraction levels are required for accurate interpretation of cVEMPs. These data highlight the importance of measuring SCM contraction strength when recording cVEMPs. Copyright © 2015 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.

Corticospinal excitability is dependent on the parameters of peripheral electric stimulation: a preliminary study.

PubMed

Chipchase, Lucy S; Schabrun, Siobhan M; Hodges, Paul W

2011-09-01

To evaluate the effect of 6 electric stimulation paradigms on corticospinal excitability. Using a same subject pre-post test design, transcranial magnetic stimulation (TMS) was used to measure the responsiveness of corticomotor pathway to biceps and triceps brachii muscles before and after 30 minutes of electric stimulation over the biceps brachii. Six different electric stimulation paradigms were applied in random order, at least 3 days apart. Motor control research laboratory. Healthy subjects (N=10; 5 women, 5 men; mean age ± SD, 26 ± 3.6y). Six different electric stimulation paradigms with varied stimulus amplitude, frequency, and ramp settings. Amplitudes of TMS-induced motor evoked potentials at biceps and triceps brachii normalized to maximal M-wave amplitudes. Electric stimulation delivered at stimulus amplitude sufficient to evoke a sensory response at both 10 Hz and 100 Hz, and stimulus amplitude to create a noxious response at 10 Hz decreased corticomotor responsiveness (all P<0.01). Stimulation sufficient to induce a motor contraction (30 Hz) applied in a ramped pattern to mimic a voluntary activation increased corticomotor responsiveness (P=0.002), whereas constant low- and high-intensity motor stimulation at 10 Hz did not. Corticomotor excitability changes were similar for both the stimulated muscle and its antagonist. Stimulus amplitude (intensity) and the nature (muscle flicker vs contraction) of motor stimulation have a significant impact on changes in corticospinal excitability induced by electric stimulation. Here, we demonstrate that peripheral electric stimulation at stimulus amplitude to create a sensory response reduces corticomotor responsiveness. Conversely, stimulus amplitude to create a motor response increases corticomotor responsiveness, but only the parameters that create a motor response that mimics a voluntary muscle contraction. Copyright © 2011 American Congress of Rehabilitation Medicine. Published by Elsevier Inc. All rights reserved.

Determination of optimal whole body vibration amplitude and frequency parameters with plyometric exercise and its influence on closed-chain lower extremity acute power output and EMG activity in resistance trained males

NASA Astrophysics Data System (ADS)

Hughes, Nikki J.

The optimal combination of Whole body vibration (WBV) amplitude and frequency has not been established. Purpose. To determine optimal combination of WBV amplitude and frequency that will enhance acute mean and peak power (MP and PP) output EMG activity in the lower extremity muscles. Methods. Resistance trained males (n = 13) completed the following testing sessions: On day 1, power spectrum testing of bilateral leg press (BLP) movement was performed on the OMNI. Days 2 and 3 consisted of WBV testing with either average (5.8 mm) or high (9.8 mm) amplitude combined with either 0 (sham control), 10, 20, 30, 40 and 50 Hz frequency. Bipolar surface electrodes were placed on the rectus femoris (RF), vastus lateralis (VL), bicep femoris (BF) and gastrocnemius (GA) muscles for EMG analysis. MP and PP output and EMG activity of the lower extremity were assessed pre-, post-WBV treatments and after sham-controls on the OMNI while participants performed one set of five repetitions of BLP at the optimal resistance determined on Day 1. Results. No significant differences were found between pre- and sham-control on MP and PP output and on EMG activity in RF, VL, BF and GA. Completely randomized one-way ANOVA with repeated measures demonstrated no significant interaction of WBV amplitude and frequency on MP and PP output and peak and mean EMGrms amplitude and EMG rms area under the curve. RF and VL EMGrms area under the curve significantly decreased (p < 0.05) with high WBV amplitude, whereas low amplitude significantly decreased GA mean and peak EMGrms amplitude and EMGrms area under the curve. VL mean EMGrms amplitude and BF mean and peak EMGrms amplitudes were significantly decreased (p < 0.05) with high WBV amplitude when compared to sham-control. WBV frequency significantly decreased (p < 0.05) VL mean and peak EMGrms amplitude. WBV frequency at 30 and 40 Hz significantly decreased (p < 0.05) GA mean EMGrms amplitude and 20 and 30 Hz significantly decreased GA peak EMGrms amplitude. MP and PP output was not significantly effected by either treatment. Conclusions. It is concluded that WBV combined with plyometric exercise does not induce alterations in subsequent MP and PP output and EMGrms activity of the lower extremity. Future studies need to address the time of WBV exposure and magnitude of external loads that will maximize strength and/or power output.

Regional Seismic Amplitude Modeling and Tomography for Earthquake-Explosion Discrimination

NASA Astrophysics Data System (ADS)

Walter, W. R.; Pasyanos, M. E.; Matzel, E.; Gok, R.; Sweeney, J.; Ford, S. R.; Rodgers, A. J.

2008-12-01

Empirically explosions have been discriminated from natural earthquakes using regional amplitude ratio techniques such as P/S in a variety of frequency bands. We demonstrate that such ratios discriminate nuclear tests from earthquakes using closely located pairs of earthquakes and explosions recorded on common, publicly available stations at test sites around the world (e.g. Nevada, Novaya Zemlya, Semipalatinsk, Lop Nor, India, Pakistan, and North Korea). We are examining if there is any relationship between the observed P/S and the point source variability revealed by longer period full waveform modeling. For example, regional waveform modeling shows strong tectonic release from the May 1998 India test, in contrast with very little tectonic release in the October 2006 North Korea test, but the P/S discrimination behavior appears similar in both events using the limited regional data available. While regional amplitude ratios such as P/S can separate events in close proximity, it is also empirically well known that path effects can greatly distort observed amplitudes and make earthquakes appear very explosion-like. Previously we have shown that the MDAC (Magnitude Distance Amplitude Correction, Walter and Taylor, 2001) technique can account for simple 1-D attenuation and geometrical spreading corrections, as well as magnitude and site effects. However in some regions 1-D path corrections are a poor approximation and we need to develop 2-D path corrections. Here we demonstrate a new 2-D attenuation tomography technique using the MDAC earthquake source model applied to a set of events and stations in both the Middle East and the Yellow Sea Korean Peninsula regions. We believe this new 2-D MDAC tomography has the potential to greatly improve earthquake-explosion discrimination, particularly in tectonically complex regions such as the Middle East.

INCREASING EVIDENCE FOR HEMISPHERICAL POWER ASYMMETRY IN THE FIVE-YEAR WMAP DATA

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hoftuft, J.; Eriksen, H. K.; Hansen, F. K.

Motivated by the recent results of Hansen et al. concerning a noticeable hemispherical power asymmetry in the Wilkinson Microwave Anisotropy Probe (WMAP) data on small angular scales, we revisit the dipole-modulated signal model introduced by Gordon et al.. This model assumes that the true cosmic microwave background signal consists of a Gaussian isotropic random field modulated by a dipole, and is characterized by an overall modulation amplitude, A, and a preferred direction, p-hat. Previous analyses of this model have been restricted to very low resolution (i.e., 3.{sup 0}6 pixels, a smoothing scale of 9 deg. FWHM, and l {approx}< 40)more » due to computational cost. In this paper, we double the angular resolution (i.e., 1.{sup 0}8 pixels and 4.{sup 0}5 FWHM smoothing scale), and compute the full corresponding posterior distribution for the five-year WMAP data. The results from our analysis are the following: the best-fit modulation amplitude for l {<=} 64 and the ILC data with the WMAP KQ85 sky cut is A = 0.072 {+-} 0.022, nonzero at 3.3{sigma}, and the preferred direction points toward Galactic coordinates (l, b) = (224 deg., - 22 deg.) {+-} 24 deg. The corresponding results for l {approx}< 40 from earlier analyses were A = 0.11 {+-} 0.04 and (l, b) = (225 deg. - 27 deg.). The statistical significance of a nonzero amplitude thus increases from 2.8{sigma} to 3.3{sigma} when increasing l{sub max} from 40 to 64, and all results are consistent to within 1{sigma}. Similarly, the Bayesian log-evidence difference with respect to the isotropic model increases from {delta}ln E = 1.8 to {delta}ln E = 2.6, ranking as 'strong evidence' on the Jeffreys' scale. The raw best-fit log-likelihood difference increases from {delta}ln L = 6.1 to {delta}ln L = 7.3. Similar, and often slightly stronger, results are found for other data combinations. Thus, we find that the evidence for a dipole power distribution in the WMAP data increases with l in the five-year WMAP data set, in agreement with the reports of Hansen et al.« less

Associations between psychosis endophenotypes across brain functional, structural, and cognitive domains.

PubMed

Blakey, R; Ranlund, S; Zartaloudi, E; Cahn, W; Calafato, S; Colizzi, M; Crespo-Facorro, B; Daniel, C; Díez-Revuelta, Á; Di Forti, M; Iyegbe, C; Jablensky, A; Jones, R; Hall, M-H; Kahn, R; Kalaydjieva, L; Kravariti, E; Lin, K; McDonald, C; McIntosh, A M; Picchioni, M; Powell, J; Presman, A; Rujescu, D; Schulze, K; Shaikh, M; Thygesen, J H; Toulopoulou, T; Van Haren, N; Van Os, J; Walshe, M; Murray, R M; Bramon, E

2018-06-01

A range of endophenotypes characterise psychosis, however there has been limited work understanding if and how they are inter-related. This multi-centre study includes 8754 participants: 2212 people with a psychotic disorder, 1487 unaffected relatives of probands, and 5055 healthy controls. We investigated cognition [digit span (N = 3127), block design (N = 5491), and the Rey Auditory Verbal Learning Test (N = 3543)], electrophysiology [P300 amplitude and latency (N = 1102)], and neuroanatomy [lateral ventricular volume (N = 1721)]. We used linear regression to assess the interrelationships between endophenotypes. The P300 amplitude and latency were not associated (regression coef. -0.06, 95% CI -0.12 to 0.01, p = 0.060), and P300 amplitude was positively associated with block design (coef. 0.19, 95% CI 0.10-0.28, p 0.38). All the cognitive endophenotypes were associated with each other in the expected directions (all p < 0.001). Lastly, the relationships between pairs of endophenotypes were consistent in all three participant groups, differing for some of the cognitive pairings only in the strengths of the relationships. The P300 amplitude and latency are independent endophenotypes; the former indexing spatial visualisation and working memory, and the latter is hypothesised to index basic processing speed. Individuals with psychotic illnesses, their unaffected relatives, and healthy controls all show similar patterns of associations between endophenotypes, endorsing the theory of a continuum of psychosis liability across the population.

Persistence and amplitude of cigarette demand in relation to quit intentions and attempts

PubMed Central

O’Connor, Richard J.; Heckman, Bryan W.; Adkison, Sarah E.; Rees, Vaughan W.; Hatsukami, Dorothy K.; Bickel, Warren K.; Cummings, K. Michael

2016-01-01

INTRODUCTION The cigarette purchase task (CPT) is a method that can be used to assess relative value of cigarettes. Based on cigarettes purchased across a price range, five derived metrics (Omax, Pmax, breakpoint, intensity, elasticity) can assess cigarette demand. A study with adolescent smokers found that these could be reduced to two latent factors: Persistence (price insensitivity) and Amplitude (volumetric consumption). We sought to replicate this structure with adult smokers, and examine how these variables relate to cessation efforts. METHOD Web-based survey conducted in 2014 among adult (18+) current daily cigarette smokers (N=1194). Participants completed the CPT, Fagerstrom Test for Nicotine Dependence (FTND), reported past-year quit attempts, and future quit intentions. We included published scales assessing perceived prevalence of smoking, social reactivity, smoker identity, and risk perception. RESULTS Our analysis supported two latent variables, Persistence and Amplitude, which correlated positively with FTND. Persistence correlated with several psychosocial factors, and was higher among those intending to quit very soon, but did not vary by number of past-year quit attempts. Amplitude differed across quit attempts and intention (p’s <.001), and in multivariable models was significantly associated with lower 30-day quit intention [OR=0.76, p=.001]. CONCLUSIONS Persistence and Amplitude factors characterized CPT data in adults, discriminated known groups (e.g., smokers by intentions to quit), and were positively associated with nicotine dependence. Factor scores also appear to relate to certain psychosocial factors, such as smoker identity and perceptions of risk. Future research should examine the predictive validity of these constructs. PMID:27048156

The time course of activation of object shape and shape+colour representations during memory retrieval.

PubMed

Lloyd-Jones, Toby J; Roberts, Mark V; Leek, E Charles; Fouquet, Nathalie C; Truchanowicz, Ewa G

2012-01-01

Little is known about the timing of activating memory for objects and their associated perceptual properties, such as colour, and yet this is important for theories of human cognition. We investigated the time course associated with early cognitive processes related to the activation of object shape and object shape+colour representations respectively, during memory retrieval as assessed by repetition priming in an event-related potential (ERP) study. The main findings were as follows: (1) we identified a unique early modulation of mean ERP amplitude during the N1 that was associated with the activation of object shape independently of colour; (2) we also found a subsequent early P2 modulation of mean amplitude over the same electrode clusters associated with the activation of object shape+colour representations; (3) these findings were apparent across both familiar (i.e., correctly coloured - yellow banana) and novel (i.e., incorrectly coloured - blue strawberry) objects; and (4) neither of the modulations of mean ERP amplitude were evident during the P3. Together the findings delineate the timing of object shape and colour memory systems and support the notion that perceptual representations of object shape mediate the retrieval of temporary shape+colour representations for familiar and novel objects.

The Time Course of Activation of Object Shape and Shape+Colour Representations during Memory Retrieval

PubMed Central

Lloyd-Jones, Toby J.; Roberts, Mark V.; Leek, E. Charles; Fouquet, Nathalie C.; Truchanowicz, Ewa G.

2012-01-01

Little is known about the timing of activating memory for objects and their associated perceptual properties, such as colour, and yet this is important for theories of human cognition. We investigated the time course associated with early cognitive processes related to the activation of object shape and object shape+colour representations respectively, during memory retrieval as assessed by repetition priming in an event-related potential (ERP) study. The main findings were as follows: (1) we identified a unique early modulation of mean ERP amplitude during the N1 that was associated with the activation of object shape independently of colour; (2) we also found a subsequent early P2 modulation of mean amplitude over the same electrode clusters associated with the activation of object shape+colour representations; (3) these findings were apparent across both familiar (i.e., correctly coloured – yellow banana) and novel (i.e., incorrectly coloured - blue strawberry) objects; and (4) neither of the modulations of mean ERP amplitude were evident during the P3. Together the findings delineate the timing of object shape and colour memory systems and support the notion that perceptual representations of object shape mediate the retrieval of temporary shape+colour representations for familiar and novel objects. PMID:23155393

Ruminal motility of stocker cattle grazed on winter wheat pasture.

PubMed

Horn, G W; Frost, D F

1982-10-01

A 2-yr study was conducted to determine whether bloat of stocker cattle grazing winter wheat pasture is a primary bloat or a secondary bloat as a result of reduced ruminal motility. Amplitude (mm Hg) and frequency of ruminal contractions (contractions/min) of steers were measured before and after the steers were placed on wheat pasture, and at about weekly intervals during the pasture grazing periods. Implantable pressure transducers and water-filled balloon cannulas were used to measure ruminal motility. During the first year, amplitude of contractions increased (P less than .005) during grazing of wheat pasture (i.e., 20.5 vs 6.7 and 21.6 vs 12.9, respectively, for steers with implanted pressure transducers and water-filled balloon cannulas). Frequency of ruminal contractions of steers on wheat pasture was not decreased (P greater than .05). In the second year, amplitudes of ruminal contractions of steers on wheat pasture ranged from 11.0 to 33.5, and were either similar or greater (P less than .05) than the mean for the pre- and post-wheat pasture period (16.5). Frequencies of ruminal contractions that ranged from 1.66 to 1.80 were observed on four dates during the pasture grazing period, and were decreased (P less than .05) as compared with the mean for the pre- and post-wheat pasture period (2.43). However, the reduced frequencies were not accompanied by reduced (P greater than .05) amplitude x frequency of contractions. The data indicate that ruminal motility is not decreased in stocker cattle grazing winter wheat pasture.

Disease Course of Patients with Unilateral Pigmentary Retinopathy

PubMed Central

Potsidis, Emorfily; Berson, Eliot L.

2011-01-01

Purpose. To evaluate the change in ocular function by eye in patients with unilateral pigmentary retinopathy. Methods. Longitudinal regression was used to estimate mean exponential rates of change in Goldmann visual field area (V4e white test light) and in full-field electroretinogram (ERG) amplitudes to 0.5- and 30-Hz white flashes in 15 patients with unilateral pigmentary retinopathy. Snellen visual acuity was assessed case by case. Results. Mean annual rates of change for the affected eyes were −4.9% for visual field area, −4.7% for ERG amplitude to 0.5-Hz flashes, and −4.6% for ERG amplitude to 30-Hz flashes. All three rates were faster than the corresponding age-related rates of change for the fellow normal eyes (P = 0.0006, P = 0.003, P = 0.03, respectively). An initial cone ERG implicit time to 30-Hz flashes in affected eyes ≥40 ms predicted a faster mean rate of decline of visual field area and of ERG amplitude to 0.5- and 30-Hz flashes (P < 0.0001 for all three measures). The visual acuity of affected eyes was more likely to decrease in patients presenting at >35 years of age than in patients presenting at a younger age (P = 0.0004). Conclusions. The affected eye in unilateral pigmentary retinopathy shows a progressive loss of peripheral retinal function that cannot be attributed to aging alone and that is faster in eyes with a more prolonged initial cone ERG implicit time. Patients presenting at >35 years of age are at greater risk for losing visual acuity. PMID:21989720

Disease course of patients with unilateral pigmentary retinopathy.

PubMed

Potsidis, Emorfily; Berson, Eliot L; Sandberg, Michael A

2011-11-29

To evaluate the change in ocular function by eye in patients with unilateral pigmentary retinopathy. Longitudinal regression was used to estimate mean exponential rates of change in Goldmann visual field area (V4e white test light) and in full-field electroretinogram (ERG) amplitudes to 0.5- and 30-Hz white flashes in 15 patients with unilateral pigmentary retinopathy. Snellen visual acuity was assessed case by case. Mean annual rates of change for the affected eyes were -4.9% for visual field area, -4.7% for ERG amplitude to 0.5-Hz flashes, and -4.6% for ERG amplitude to 30-Hz flashes. All three rates were faster than the corresponding age-related rates of change for the fellow normal eyes (P = 0.0006, P = 0.003, P = 0.03, respectively). An initial cone ERG implicit time to 30-Hz flashes in affected eyes ≥ 40 ms predicted a faster mean rate of decline of visual field area and of ERG amplitude to 0.5- and 30-Hz flashes (P < 0.0001 for all three measures). The visual acuity of affected eyes was more likely to decrease in patients presenting at >35 years of age than in patients presenting at a younger age (P = 0.0004). The affected eye in unilateral pigmentary retinopathy shows a progressive loss of peripheral retinal function that cannot be attributed to aging alone and that is faster in eyes with a more prolonged initial cone ERG implicit time. Patients presenting at >35 years of age are at greater risk for losing visual acuity.

Musical rhythm and pitch: A differential effect on auditory dynamics as revealed by the N1/MMN/P3a complex.

PubMed

Lelo-de-Larrea-Mancera, E Sebastian; Rodríguez-Agudelo, Yaneth; Solís-Vivanco, Rodolfo

2017-06-01

Music represents a complex form of human cognition. To what extent our auditory system is attuned to music is yet to be clearly understood. Our principal aim was to determine whether the neurophysiological operations underlying pre-attentive auditory change detection (N1 enhancement (N1e)/Mismatch Negativity (MMN)) and the subsequent involuntary attentional reallocation (P3a) towards infrequent sound omissions, are influenced by differences in musical content. Specifically, we intended to explore any interaction effects that rhythmic and pitch dimensions of musical organization may have over these processes. Results showed that both the N1e and MMN amplitudes were differentially influenced by rhythm and pitch dimensions. MMN latencies were shorter for musical structures containing both features. This suggests some neurocognitive independence between pitch and rhythm domains, but also calls for further address on possible interactions between both of them at the level of early, automatic auditory detection. Furthermore, results demonstrate that the N1e reflects basic sensory memory processes. Lastly, we show that the involuntary switch of attention associated with the P3a reflects a general-purpose mechanism not modulated by musical features. Altogether, the N1e/MMN/P3a complex elicited by infrequent sound omissions revealed evidence of musical influence over early stages of auditory perception. Copyright © 2017 Elsevier Ltd. All rights reserved.

[Clinical and neurophysiological heterogeneity of attention deficit hyperactivity disorder].

PubMed

Chutko, L S; Yakovenko, E A; Surushkina, S Yu; Anisimova, T I; Kropotov, Yu D

To determine clinical/neurophysiological characteristics of different forms of attention deficit hyperactivity disorder (ADHD) and the efficacy of treatment with cerebrolysin. Sixty children, aged 9 to 12 years, with ADHD were examined using clinical and electroencephalographic methods. Idiopathic and residual-organic forms were compared. The study shows significantly higher levels of impulsivity and hyperactivity in children with residual-organic form of the disease. There were significant differences in the amplitude component of engaging in action (P3 Go) and the amplitude of the action suppression component (P3 NOGO) in patients with different forms of ADHD. The high clinical efficacy (improvement in 70.0% of patients with idiopathic form of ADHD and 86.7% of patients with residual-organic form of the disease) was found.

Event-related potentials for gender discrimination: an examination between differences in gender discrimination between males and females.

PubMed

Suyama, Natsuka; Hoshiyama, Minoru; Shimizu, Hideki; Saito, Hirofumi

2008-09-01

The event-related potentials (ERP) following presentation of male and female faces were investigated to study differences in the gender discrimination process. Visual stimuli from four categories including male and female faces were presented. For the male subjects, the P220 amplitude of the T5 area following viewing of a female face was significantly larger than that following viewing of a male face. On the other hand for female subjects, the P170 amplitude of the Cz area following observation of a male face was larger than that for a female face. The results indicate that the neural processes, including responsive brain areas used for gender discrimination by observing faces, are different between males and females.

Electric field measurement of two commercial active/sham coils for transcranial magnetic stimulation.

PubMed

Smith, James Evan; Peterchev, Angel V

2018-06-22

Sham TMS coils isolate the ancillary effects of their active counterparts, but typically induce low-strength electric fields (E-fields) in the brain, which could be biologically active. We measured the E-fields induced by two pairs of commonly-used commercial active/sham coils. Approach: E-field distributions of the active and sham configurations of the Magstim 70 mm AFC and MagVenture Cool-B65 A/P coils were measured over a 7-cm-radius, hemispherical grid approximating the cortical surface. Peak E-field strength was recorded over a range of pulse amplitudes. Main results: The Magstim and MagVenture shams induce peak E-fields corresponding to 25.3% and 7.72% of their respective active values. The MagVenture sham has an E-field distribution shaped like its active counterpart. The Magstim sham induces nearly zero E-field under the coil's center, and its peak E-field forms a diffuse oval 3-7 cm from the center. Electrical scalp stimulation paired with the MagVenture sham is estimated to increase the sham E-field in the brain up to 10%. Significance: Different commercial shams induce different E-field strengths and distributions in the brain, which should be considered in interpreting outcomes of sham stimulation. © 2018 IOP Publishing Ltd.

On the impact of examiners on latencies and amplitudes in cervical and ocular vestibular-evoked myogenic potentials evaluated over a large sample (N = 1,038).

PubMed

Ertl, Matthias; Boegle, R; Kirsch, V; Dieterich, M

2016-02-01

Vestibular-evoked myogenic potentials (VEMPs) are frequently used in the clinical diagnosis and research of vertigo syndromes. Altered latencies or amplitudes are typically interpreted as an indication of disturbance in the processing of vestibular stimuli along the otolithic pathways. Correct interpretation, however, can be difficult as VEMP amplitudes can vary greatly across subjects and across laboratories, likely because they are very sensitive to measurement conditions. Here, we attempted to quantify the impact of examiner differences on VEMP data. We collected data from 1,038 people using eight different experimental examiners, and investigated the effect of examiner on VEMP latencies and amplitudes. We found that the examiner collecting the data had a strong effect on outcome measures with significant differences (p < 0.001) in cVEMP and oVEMP latencies and in oVEMP amplitudes. No significant differences between examiners were found for the cVEMP amplitudes. When we compared the healthy and pathological sides of patients with a clinically diagnosed unilateral disease, no significant differences between sides were found. Given our results and the results reported in the literature, we conclude that the signal features of VEMPs are very sensitive to variables that may be influenced by the examiner. The field should therefore work on a better standard for VEMP recordings.

Can Vestibular-Evoked Myogenic Potentials Help Differentiate Ménière Disease from Vestibular Migraine?

PubMed Central

Zuniga, M. Geraldine; Janky, Kristen L.; Schubert, Michael C.; Carey, John P.

2013-01-01

Objectives To characterize both cervical and ocular vestibular-evoked myogenic potential (cVEMP, oVEMP) responses to air-conducted sound (ACS) and midline taps in Ménière disease (MD), vestibular migraine (VM), and controls, as well as to determine if cVEMP or oVEMP responses can differentiate MD from VM. Study Design Prospective cohort study. Setting Tertiary referral center. Subjects and Methods Unilateral definite MD patients (n = 20), VM patients (n = 21) by modified Neuhauser criteria, and age-matched controls (n = 28). cVEMP testing used ACS (clicks), and oVEMP testing used ACS (clicks and 500-Hz tone bursts) and midline tap stimuli (reflex hammer and Mini-Shaker). Outcome parameters were cVEMP peak-to-peak amplitudes and oVEMP n10 amplitudes. Results Relative to controls, MD and VM groups both showed reduced click-evoked cVEMP (P < .001) and oVEMP (P < .001) amplitudes. Only the MD group showed reduction in tone-evoked amplitudes for oVEMP. Tone-evoked oVEMPs differentiated MD from controls (P = .001) and from VM (P = .007). The oVEMPs in response to the reflex hammer and Mini-Shaker midline taps showed no differences between groups (P > .210). Conclusions Using these techniques, VM and MD behaved similarly on most of the VEMP test battery. A link in their pathophysiology may be responsible for these responses. The data suggest a difference in 500-Hz tone burst–evoked oVEMP responses between MD and MV as a group. However, no VEMP test that was investigated segregated individuals with MD from those with VM. PMID:22267492

The effect of reference choices on the spatio-temporal analysis of brain evoked potentials: the use of infinite reference.

PubMed

Yao, Dezhong; Wang, Li; Arendt-Nielsen, Lars; Chen, Andrew C N

2007-11-01

Reference is a very virtual issue in EEG and ERP. Understanding the difference of various references will make the applications more confident. In this work, somatosensory evoked potential (SEP) with stimulation on the right hand was studied. The SEP spatio-temporal analysis was conducted comparatively on six references, left mastoid (contralateral mastoid reference, CM), right mastoid (ipsilateral mastoid reference, IM), linked mastoids (LM), average reference (AR), vertex reference (Cz) and the infinity reference (IR) newly proposed in 2001. Among the six, CM is the one used in actual recordings, and the other five are obtained by off-line re-referencing. The comparison is conducted on four selected components (P30 ms, P40 ms, N90 ms and P230 ms) in both temporal and spatial aspects. The results show that references may have a distinct influence on the amplitudes of the scalp potentials, with relative error at some electrodes larger than 500%, and for some electrodes it may even change the polarity. Pair-wise multiple comparison (Tukey test) shows that the differences of peak values among various references are very significant (P<0.001) between Cz and IR\\CM\\IM\\LM, and significant (P<0.01) between Cz and AR for component N90 ms; very significant (P<0.001) between Cz and IR\\CM\\IM\\LM\\AR, significant between IMLM and AR (P<0.01), CM and AR (P<0.05) for component P230 ms. The amplitude value order is CM/IM> or =LM>IR>AR>Cz. The two-ways (the six references vs. the four Peaks) repeated measures ANOVA test shows the effect of different references depends on various components; there is a statistically significant interaction between reference and the peak (P=<0.001). While for the spatial map of the potential amplitude, references will not affect the amplitude map shape if the color-bar is selected automatically, but if a fixed color-bar is chosen for data of various references, they may show some differences. These results mean a common reference is important for producing a comparable result between labs. As IR is theoretically a constant reference, we recommend it as the common choice in the future.

The effect of indomethacin on the muscarinic induced contractions in the isolated normal guinea pig urinary bladder.

PubMed

Rahnama'i, Mohammad S; van Koeveringe, Gommert A; van Kerrebroeck, Philip E V; de Wachter, Stefan G G

2013-02-07

To investigate the effect of prostaglandin depletion by means of COX-inhibition on cholinergic enhanced spontaneous contractions. The urethra and bladder of 9 male guinea pigs (weight 270-300 g) were removed and placed in an organ bath with Krebs' solution. A catheter was passed through the urethra through which the intravesical pressure was measured. The muscarinic agonist arecaidine, the non-selective COX inhibitor indomethacin, and PGE2 were subsequently added to the organ bath. The initial average frequency and amplitude of spontaneous contractions in the first 2 minutes after arecaidine application were labelled F(ini) and P(ini), respectively. The steady state frequency (F(steady)) and amplitude (P(steady)) were defined as the average frequency and amplitude during the 5 minutes before the next wash out. Application of 1 μM PGE2 increased the amplitude of spontaneous contractions without affecting frequency. 10 μM of indomethacin reduced amplitude but not frequency.The addition of indomethacin did not alter F(ini) after the first application (p = 0.7665). However, after the second wash, F(ini) was decreased (p = 0.0005). F(steady), P(steady) and P(ini) were not significantly different in any of the conditions. These effects of indomethacin were reversible by PGE2 addition.. Blocking PG synthesis decreased the cholinergically stimulated autonomous contractions in the isolated bladder. This suggests that PG could modify normal cholinergically evoked response. A combination of drugs inhibiting muscarinic receptors and PG function or production can then become an interesting focus of research on a treatment for overactive bladder syndrome.

Evidence for a differential contribution of early perceptual and late cognitive processes during encoding to episodic memory impairment in schizophrenia.

PubMed

Green, Amity E; Fitzgerald, Paul B; Johnston, Patrick J; Nathan, Pradeep J; Kulkarni, Jayashri; Croft, Rodney J

2017-08-01

Schizophrenia is characterised by significant episodic memory impairment that is thought to be related to problems with encoding, however the neuro-functional mechanisms underlying these deficits are not well understood. The present study used a subsequent recognition memory paradigm and event-related potentials (ERPs) to investigate temporal aspects of episodic memory encoding deficits in schizophrenia. Electroencephalographic data was recorded in 24 patients and 19 healthy controls whilst participants categorised single words as pleasant/unpleasant. ERPs were generated to subsequently recognised versus unrecognised words on the basis of a forced-choice recognition memory task. Subsequent memory effects were examined with the late positive component (LPP). Group differences in N1, P2, N400 and LPP were examined for words correctly recognised. Patients performed more poorly than controls on the recognition task. During encoding patients had significantly reduced N400 and LPP amplitudes than controls. LPP amplitude correlated with task performance however amplitudes did not differ between patients and controls as a function of subsequent memory. No significant differences in N1 or P2 amplitude or latency were observed. The present results indicate that early sensory processes are intact and dysfunctional higher order cognitive processes during encoding are contributing to episodic memory impairments in schizophrenia.

Color vision in attention-deficit/hyperactivity disorder: a pilot visual evoked potential study.

PubMed

Kim, Soyeon; Banaschewski, Tobias; Tannock, Rosemary

2015-01-01

Individuals with attention-deficit/hyperactivity disorder (ADHD) are reported to manifest visual problems (including ophthalmological and color perception, particularly for blue-yellow stimuli), but findings are inconsistent. Accordingly, this study investigated visual function and color perception in adolescents with ADHD using color Visual Evoked Potentials (cVEP), which provides an objective measure of color perception. Thirty-one adolescents (aged 13-18), 16 with a confirmed diagnosis of ADHD, and 15 healthy peers, matched for age, gender, and IQ participated in the study. All underwent an ophthalmological exam, as well as electrophysiological testing color Visual Evoked Potentials (cVEP), which measured the latency and amplitude of the neural P1 response to chromatic (blue-yellow, red-green) and achromatic stimuli. No intergroup differences were found in the ophthalmological exam. However, significantly larger P1 amplitude was found for blue and yellow stimuli, but not red/green or achromatic stimuli, in the ADHD group (particularly in the medicated group) compared to controls. Larger amplitude in the P1 component for blue-yellow in the ADHD group compared to controls may account for the lack of difference in color perception tasks. We speculate that the larger amplitude for blue-yellow stimuli in early sensory processing (P1) might reflect a compensatory strategy for underlying problems including compromised retinal input of s-cones due to hypo-dopaminergic tone. Copyright © 2014 Spanish General Council of Optometry. Published by Elsevier Espana. All rights reserved.

Tsunami Size Distributions at Far-Field Locations from Aggregated Earthquake Sources

NASA Astrophysics Data System (ADS)

Geist, E. L.; Parsons, T.

2015-12-01

The distribution of tsunami amplitudes at far-field tide gauge stations is explained by aggregating the probability of tsunamis derived from individual subduction zones and scaled by their seismic moment. The observed tsunami amplitude distributions of both continental (e.g., San Francisco) and island (e.g., Hilo) stations distant from subduction zones are examined. Although the observed probability distributions nominally follow a Pareto (power-law) distribution, there are significant deviations. Some stations exhibit varying degrees of tapering of the distribution at high amplitudes and, in the case of the Hilo station, there is a prominent break in slope on log-log probability plots. There are also differences in the slopes of the observed distributions among stations that can be significant. To explain these differences we first estimate seismic moment distributions of observed earthquakes for major subduction zones. Second, regression models are developed that relate the tsunami amplitude at a station to seismic moment at a subduction zone, correcting for epicentral distance. The seismic moment distribution is then transformed to a site-specific tsunami amplitude distribution using the regression model. Finally, a mixture distribution is developed, aggregating the transformed tsunami distributions from all relevant subduction zones. This mixture distribution is compared to the observed distribution to assess the performance of the method described above. This method allows us to estimate the largest tsunami that can be expected in a given time period at a station.

Acoustic myography as an indicator of force during sustained contractions of a small hand muscle.

PubMed

Goldenberg, M S; Yack, H J; Cerny, F J; Burton, H W

1991-01-01

To test the hypothesis that muscle sound amplitudes would remain constant during sustained submaximal isometric contractions, we recorded acoustic myograms from the abductor digiti minimi muscle in 12 subjects at 15, 25, 50, and 75% of a maximum voluntary contraction (MVC). Muscle sounds were detected with an omni-directional electret microphone encased in closed-cell foam and attached to the skin over the muscle. Acoustic amplitudes from the middle and end of the sustained contractions were compared with the amplitudes from the beginning of contractions to determine whether acoustic amplitudes varied in magnitude as force remained constant. Physiological tremor was eliminated from the acoustic signal by use of a Fourier truncation at 14 Hz. The amplitudes of the acoustic signal at a contraction intensity of 75% MVC remained constant, reflecting force production over time. At 50% MVC, the root-mean-square amplitude decreased from the beginning to the end of the contraction (P less than 0.05). Acoustic amplitudes increased over time at 15 and 25% MVC and were significantly higher at the end of the contractions than at the beginning (P less than 0.05). Alterations in the acoustic amplitude, which reflect changes in the lateral vibrations of the muscle, may be indicative of the different recruitment strategies used to maintain force during sustained isometric contractions.

Some factors affecting efficiency of the ultrasound-aided enzymatic hydrolysis of cotton cellulose.

PubMed

Szabo, Orsolya Erzsebet; Csiszar, Emilia

2017-01-20

The efficiency of the enzymatic hydrolysis of cellulose with low frequency ultrasound (horn-type reactor) was investigated and characterized by the concentration of reducing sugars liberated. Small squares of bleached cotton fabric were used for comparing the efficiency of different agitation methods (i.e. magnetic stirring, horizontal and vertical mechanical agitation) and ultrasound. At the same enzyme dosage and substrate level, sonication at 40, 60 and 80% amplitudes (I diss : 16.2, 32.2 and 43.4W/cm 2 , respectively) intensified the hydrolysis over the most efficient mechanical agitation (i.e. magnetic stirring) alone by 15%, 24% and 54%, respectively. For mapping the ultrasonicated field, fabric layers positioned perpendicularly to the ultrasonic probe at different distances were hydrolysed. The optimal operating conditions were reached at 60% amplitude and 9mm The yield depended mainly on important factors such as amplitude, the presence of a reflector, distance from horn and form of substrate. Copyright © 2016 Elsevier Ltd. All rights reserved.

Modulation of soleus corticospinal excitability during Achilles tendon vibration.

PubMed

Lapole, Thomas; Temesi, John; Arnal, Pierrick J; Gimenez, Philippe; Petitjean, Michel; Millet, Guillaume Y

2015-09-01

Soleus (SOL) corticospinal excitability has been reported to increase during Achilles tendon vibration. The aim of the present study was to further investigate SOL corticospinal excitability and elucidate the changes to intracortical mechanisms during Achilles tendon vibration. Motor-evoked potentials (MEPs) were elicited in the SOL by transcranial magnetic stimulation (TMS) of the corresponding motor cortical area of the leg with and without 50-Hz Achilles tendon vibration. SOL input-output curves were determined. Paired-pulse protocols were also performed to investigate short-interval intracortical inhibition (SICI) and intracortical facilitation (ICF) by conditioning test TMS pulses with sub-threshold TMS pulses at inter-stimulus intervals of 3 and 13 ms, respectively. During Achilles tendon vibration, motor threshold was lower than in the control condition (43 ± 13 vs. 49 ± 11 % of maximal stimulator output; p = 0.008). Input-output curves were also influenced by vibration, i.e. there was increased maximal MEP amplitude (0.694 ± 0.347 vs. 0.268 ± 0.167 mV; p < 0.001), decreased TMS intensity to elicit a MEP of half the maximal MEP amplitude (100 ± 13 vs. 109 ± 9 % motor threshold; p = 0.009) and a strong tendency for decreased slope constant (0.076 ± 0.04 vs. 0.117 ± 0.04; p = 0.068). Vibration reduced ICF (98 ± 61 vs. 170 ± 105 % of test MEP amplitude; p = 0.05), but had no effect on SICI (53 ± 26 vs. 48 ± 22 % of test MEP amplitude; p = 0.68). The present results further document the increased vibration-induced corticospinal excitability in the soleus muscle and suggest that this increase is not mediated by changes in SICI or ICF.

Does transcutaneous nerve stimulation have effect on sympathetic skin response?

PubMed

Okuyucu, E Esra; Turhanoğlu, Ayşe Dicle; Guntel, Murat; Yılmazer, Serkan; Savaş, Nazan; Mansuroğlu, Ayhan

2018-01-01

This study examined the effects of transcutaneous electrical nerve stimulation (TENS) on the sympathetic nerve system by sympathetic skin response test. Fifty-five healthy volunteers received either: (i) 30minutes TENS (25 participants) (ii) 30minutes sham TENS (30 participants) and SSR test was performed pre- and post-TENS. The mean values of latency and peak-to-peak amplitude of five consecutive SSRs were calculated. A significant amplitude difference was found between TENS and sham TENS group both in right and left hand (p=0.04, p=0.01, respectively). However there was no significant latancy difference between two groups (p>0.05 ). TENS has an inhibitory effect on elicited SNS responses when compared with sham TENS control group. Copyright © 2017 Elsevier Ltd. All rights reserved.

Beam normal spin asymmetry for the e p →e Δ (1232 ) process

NASA Astrophysics Data System (ADS)

Carlson, Carl E.; Pasquini, Barbara; Pauk, Vladyslav; Vanderhaeghen, Marc

2017-12-01

We calculate the single spin asymmetry for the e p →e Δ (1232 ) process, for an electron beam polarized normal to the scattering plane. Such single spin asymmetries vanish in the one-photon exchange approximation and are directly proportional to the absorptive part of a two-photon exchange amplitude. As the intermediate state in such a two-photon exchange process is on its mass shell, the asymmetry allows one to access for the first time the on-shell Δ →Δ as well as N*→Δ electromagnetic transitions. We present the general formalism to describe the e p →e Δ beam normal spin asymmetry, and we provide a numerical estimate of its value using the nucleon, Δ (1232 ), S11(1535 ), and D13(1520 ) intermediate states. We compare our results with the first data from the Qweak@JLab experiment and give predictions for the A4@MAMI experiment.

The Role of Physical Fitness in the Neurocognitive Performance of Task Switching in Older Persons with Mild Cognitive Impairment.

PubMed

Tsai, Chia-Liang; Pai, Ming-Chyi; Ukropec, Jozef; Ukropcová, Barbara

2016-04-23

Although elderly people with amnestic mild cognitive impairment (aMCI) have been found to show impaired behavioral performance in task switching, no research has yet explored the electrophysiological mechanisms and the potential correlation between physical fitness and neurocognitive (i.e., behavioral and electrophysiological) performance in aMCI. The present study was thus aimed to examine whether there are differences in electrophysiological (i.e., event-related potential) performance between aMCI participants and controls when performing a task-switching paradigm, and to investigate the role of physical fitness in the relationship between neurocognitive performance and aMCI. Sixty participants were classified into aMCI (n = 30) and control (n = 30) groups, and performed a task-switching paradigm with concomitant electrophysiological recording, as well as underwent senior functional physical fitness tests. The aMCI group showed comparable scores on most parts of the physical fitness tests, but reduced lower body flexibility and VO2max as compared to the control group. When performing the task-switching paradigm, the aMCI group showed slower reaction times in the heterogeneous condition and larger global switching costs, although no significant difference was observed in accuracy rates between the two groups. In addition, the aMCI group showed significantly prolonged P3 latencies in the homogeneous and heterogeneous conditions, and a smaller P3 amplitude only in the heterogeneous condition. The level of cardiorespiratory fitness was significantly correlated with P3 amplitude in the aMCI group, particularly in the heterogeneous condition of the task-switching paradigm. These results show that the aMCI group exhibited abnormalities in their neurocognitive performance when performing the task-switching paradigm and such a deficit was likely associated with reduced cardiorespiratory fitness, which was shown to be the important predictor of neurocognitive performance.

The effect of learning on feedback-related potentials in adolescents with dyslexia: an EEG-ERP study.

PubMed

Kraus, Dror; Horowitz-Kraus, Tzipi

2014-01-01

Individuals with dyslexia exhibit associated learning deficits and impaired executive functions. The Wisconsin Card Sorting Test (WCST) is a learning-based task that relies heavily on executive functioning, in particular, attention shift and working memory. Performance during early and late phases of a series within the task represents learning and implementation of a newly learned rule. Here, we aimed to examine two event-related potentials associated with learning, feedback-related negativity (FRN)-P300 complex, in individuals with dyslexia performing the WCST. Adolescents with dyslexia and age-matched typical readers performed the Madrid card sorting test (MCST), a computerized version of the WCST. Task performance, reading measures, and cognitive measures were collected. FRN and the P300 complex were acquired using the event-related potentials methodology and were compared in early vs late errors within a series. While performing the MCST, both groups showed a significant reduction in average reaction times and a trend toward decreased error rates. Typical readers performed consistently better than individuals with dyslexia. FRN amplitudes in early phases were significantly smaller in dyslexic readers, but were essentially equivalent to typical readers in the late phase. P300 amplitudes were initially smaller among readers with dyslexia and tended to decrease further in late phases. Differences in FRN amplitudes for early vs late phases were positively correlated with those of P300 amplitudes in the entire sample. Individuals with dyslexia demonstrate a behavioral and electrophysiological change within single series of the MCST. However, learning patterns seem to differ between individuals with dyslexia and typical readers. We attribute these differences to the lower baseline performance of individuals with dyslexia. We suggest that these changes represent a fast compensatory mechanism, demonstrating the importance of learning strategies on reading among individuals with dyslexia.

Correlation Between Resting Testosterone/Cortisol Ratio and Sound-Induced Vasoconstriction at Fingertip in Men

PubMed Central

Ooishi, Yuuki

2018-01-01

A sound-induced sympathetic tone has been used as an index for orienting responses to auditory stimuli. The resting testosterone/cortisol ratio is a biomarker of social aggression that drives an approaching behavior in response to environmental stimuli, and a higher testosterone level and a lower cortisol level can facilitate the sympathetic response to environmental stimuli. Therefore, it is possible that the testosterone/cortisol ratio is correlated with the sound-induced sympathetic tone. The current study investigated the relationship between the resting testosterone/cortisol ratio and vasoconstriction induced by listening to sound stimuli. Twenty healthy males aged 29.0 ± 0.53 years (mean ± S.E.M) participated in the study. They came to the laboratory for 3 days and listened to one of three types of sound stimuli for 1 min on each day. Saliva samples were collected for an analysis of salivary testosterone and cortisol levels on the day of each experiment. After the collecting the saliva sample, we measured the blood volume pulse (BVP) amplitude at a fingertip. Since vasoconstriction is mediated by the activation of the sympathetic nerves, the strength of the reduction in BVP amplitude at a fingertip was called the BVP response (finger BVPR). No difference was observed between the sound-induced finger BVPR for the three types of sound stimuli (p = 0.779). The correlation coefficient between the sound-induced finger BVPR and the salivary testosterone/cortisol ratio within participants was significantly different from no correlation (p = 0.011) and there was a trend toward a significance in the correlation between the sound-induced finger BVPR and the salivary testosterone/cortisol ratio between participants (r = 0.39, p = 0.088). These results suggest that the testosterone/cortisol ratio affects the difference in the sound-evoked sympathetic response. PMID:29559922

Correlation Between Resting Testosterone/Cortisol Ratio and Sound-Induced Vasoconstriction at Fingertip in Men.

PubMed

Ooishi, Yuuki

2018-01-01

A sound-induced sympathetic tone has been used as an index for orienting responses to auditory stimuli. The resting testosterone/cortisol ratio is a biomarker of social aggression that drives an approaching behavior in response to environmental stimuli, and a higher testosterone level and a lower cortisol level can facilitate the sympathetic response to environmental stimuli. Therefore, it is possible that the testosterone/cortisol ratio is correlated with the sound-induced sympathetic tone. The current study investigated the relationship between the resting testosterone/cortisol ratio and vasoconstriction induced by listening to sound stimuli. Twenty healthy males aged 29.0 ± 0.53 years (mean ± S.E.M) participated in the study. They came to the laboratory for 3 days and listened to one of three types of sound stimuli for 1 min on each day. Saliva samples were collected for an analysis of salivary testosterone and cortisol levels on the day of each experiment. After the collecting the saliva sample, we measured the blood volume pulse (BVP) amplitude at a fingertip. Since vasoconstriction is mediated by the activation of the sympathetic nerves, the strength of the reduction in BVP amplitude at a fingertip was called the BVP response (finger BVPR). No difference was observed between the sound-induced finger BVPR for the three types of sound stimuli ( p = 0.779). The correlation coefficient between the sound-induced finger BVPR and the salivary testosterone/cortisol ratio within participants was significantly different from no correlation ( p = 0.011) and there was a trend toward a significance in the correlation between the sound-induced finger BVPR and the salivary testosterone/cortisol ratio between participants ( r = 0.39, p = 0.088). These results suggest that the testosterone/cortisol ratio affects the difference in the sound-evoked sympathetic response.

Pre-movement gating of somatosensory evoked potentials in Segawa disease.

PubMed

Kimura, Kazue; Nagao, Yuri; Hachimori, Kei; Hayashi, Masaharu; Nomura, Yoshiko; Segawa, Masaya

2016-01-01

Segawa disease (SD), an autosomal dominant dopa-responsive dystonia with marked diurnal fluctuation, can be clinically classified into the postural dystonia type (SD-P) and action dystonia type (SD-A). Compared to SD-A, SD-P has an earlier onset and is characterized by postural dystonia. In SD-A, along with postural dystonia, dystonic movements appear in late childhood. To evaluate the differences between these two types of SD, we studied the gating of SEPs, which is useful to investigate sensory-motor integration and might be one of the methods to detect the thalamo-cortical involvement. Fourteen patients with SD (11-63 years) and 18 age-matched normal subjects (11-51 years) were studied. Among the 14 patients with SD, 8 patients had SD-P and 6 had SD-A. Using median nerve stimulation at the wrist, the amplitude of the frontal N30 (FrN30) was compared between pre-movement and rest conditions. We found that the amplitude of the contralateral FrN30 was attenuated before movement in normal controls and in the majority of both SD types. On the other hand, the pre-movement-rest amplitude ratio in patients with SD-A was significantly larger than in patients with SD-P (P=0.0025). No significant differences were observed in the pre-movement-rest ratio between SD-P and normal subjects. The preservation or impairment of pre-movement gating shown here suggests a physiological difference between the two types of SD. More specifically, sensorimotor integration of the basal ganglia-thalamo-cortical circuits may be intact in SD-P, but are affected in SD-A. We discuss the different pathophysiology seen in the different phenotype of SD based on the different developmental involvement in the basal ganglia. Copyright © 2015 The Japanese Society of Child Neurology. Published by Elsevier B.V. All rights reserved.

[P300 event-related potentials in stutterers pre and post treatment: a pilot study].

PubMed

Andrade, Claudia Regina Furquim de; Sassi, Fernanda Chiarion; Matas, Carla Gentile; Neves, Ivone Ferreira; Martins, Vanessa Oliveira

2007-01-01

P300 event-related potential has been used as an instrument to establish the diagnosis of several disorders as well as to assess therapeutic outcomes. to investigate the relationship between stuttering amelioration and cerebral activity. P300 event-related potentials were obtained in three adult males, all stutterers, aged 20 to 31 years, pre and post-treatment, verifying changes in wave amplitude and latency between waves. results indicate a significant positive correlation between the reduction in the percentage of stuttered syllables and the improvement in wave amplitude for the right ear. stutterers can exhibit different patterns of interhemispheric activity with a tonal P300 task after undergoing a fluency-enhancing program.

Neural mechanisms underlying conflict monitoring over risky decision alternatives: evidence from ERP in a Go/Nogo task.

PubMed

Wang, Shuzhen; Hui, Ning; Zhou, Xinsheng; He, Kaifeng; Yu, Yuanyuan; Shuai, Jing

2014-09-01

This study assessed conflict monitoring during presentation of risky decision alternatives, as indexed by the Nogo-N2, Nogo-P3, N2d and P3d event-related potentials (ERP). Decision-makers were tested on a Go/Nogo gambling task in which gain/loss outcomes as well as stimulus type (Go/Nogo) were equiprobable. Frontal-central Nogo-N2 and Nogo-P3 did not significantly differ across risky decision alternatives, whereas N2d and P3d amplitudes were more sensitive to the nature of risky decision alternatives. Frontal-central N2d was moderated by the magnitude of alternatives, with N2d amplitude greater for large than small alternatives, a result that suggests a greater degree of conflict monitoring for the former. Central P3d was associated with alternative valence, such that P3d amplitude was greater for loss than gain valences, again suggestive of more conflict monitoring for the former. The N2d and P3d potentials in risky decision alternatives are discussed in terms of the functional significance of the N2/P3 complex.

Observational calibration of the projection factor of Cepheids. I. The type II Cepheid κ Pavonis

NASA Astrophysics Data System (ADS)

Breitfelder, J.; Kervella, P.; Mérand, A.; Gallenne, A.; Szabados, L.; Anderson, R. I.; Willson, M.; Le Bouquin, J.-B.

2015-04-01

Context. The distance of pulsating stars, in particular Cepheids, are commonly measured using the parallax of pulsation technique. The different versions of this technique combine measurements of the linear diameter variation (from spectroscopy) and the angular diameter variation (from photometry or interferometry) amplitudes, to retrieve the distance in a quasi-geometrical way. However, the linear diameter amplitude is directly proportional to the projection factor (hereafter p-factor), which is used to convert spectroscopic radial velocities (i.e., disk integrated) into pulsating (i.e., photospheric) velocities. The value of the p-factor and its possible dependence on the pulsation period are still widely debated. Aims: Our goal is to measure an observational value of the p-factor of the type-II Cepheid κ Pavonis. Methods: The parallax of the type-II Cepheid κ Pav was measured with an accuracy of 5% using HST/FGS. We used this parallax as a starting point to derive the p-factor of κ Pav, using the SPIPS technique (Spectro-Photo-Interferometry of Pulsating Stars), which is a robust version of the parallax-of-pulsation method that employs radial velocity, interferometric and photometric data. We applied this technique to a combination of new VLTI/PIONIER optical interferometric angular diameters, new CORALIE and HARPS radial velocities, as well as multi-colour photometry and radial velocities from the literature. Results: We obtain a value of p = 1.26 ± 0.07 for the p-factor of κ Pav. This result agrees with several of the recently derived Period-p-factor relationships from the literature, as well as previous observational determinations for Cepheids. Conclusions: Individual estimates of the p-factor are fundamental to calibrating the parallax of pulsation distances of Cepheids. Together with previous observational estimates, the projection factor we obtain points to a weak dependence of the p-factor on period. Based on observations realized with ESO facilities at Paranal Observatory under program IDs 091.D-0020 and 093.D-0316.Based on observations collected at ESO La Silla Observatory using the Coralie spectrograph mounted to the Swiss 1.2 m Euler telescope, under program CNTAC2014A-5.

Systematic assessment of noise amplitude generated by toys intended for young children.

PubMed

Mahboubi, Hossein; Oliaei, Sepehr; Badran, Karam W; Ziai, Kasra; Chang, Janice; Zardouz, Shawn; Shahriari, Shawn; Djalilian, Hamid R

2013-06-01

To systematically evaluate the noise generated by toys targeted for children and to compare the results over the course of 4 consecutive holiday shopping seasons. Experimental study. Academic medical center. During 2008-2011, more than 200 toys marketed for children older than 6 months were screened for loudness. The toys with sound output of more than 80 dBA at speaker level were retested in a soundproof audiometry booth. The generated sound amplitude of each toy was measured at speaker level and at 30 cm away from the speaker. Ninety different toys were analyzed. The mean (SD) noise amplitude was 100 (8) dBA (range, 80-121 dBA) at the speaker level and 80 (11) dBA (range, 60-109 dBA) at 30 cm away from the speaker. Eighty-eight (98%) had more than an 85-dBA noise amplitude at speaker level, whereas 19 (26%) had more than an 85-dBA noise amplitude at a 30-cm distance. Only the mean noise amplitude at 30 cm significantly declined during the studied period (P < .001). There was no significant difference in mean noise amplitude of different toys specified for different age groups. Our findings demonstrate the persistence of extremely loud toys marketed for very young children. Acoustic trauma from toys remains a potential risk factor for noise-induced hearing loss in this age group, warranting promotion of public awareness and regulatory considerations for manufacture and marketing of toys.

Eversion Strength and Surface Electromyography Measures With and Without Chronic Ankle Instability Measured in 2 Positions.

PubMed

Donnelly, Lindsy; Donovan, Luke; Hart, Joseph M; Hertel, Jay

2017-07-01

Individuals with chronic ankle instability (CAI) have demonstrated strength deficits compared to healthy controls; however, the influence of ankle position on force measures and surface electromyography (sEMG) activation of the peroneus longus and brevis has not been investigated. The purpose of this study was to compare sEMG amplitudes of the peroneus longus and brevis and eversion force measures in 2 testing positions, neutral and plantarflexion, in groups with and without CAI. Twenty-eight adults (19 females, 9 males) with CAI and 28 healthy controls (19 females, 9 males) participated. Hand-held dynamometer force measures were assessed during isometric eversion contractions in 2 testing positions (neutral, plantarflexion) while surface sEMG amplitudes of the peroneal muscles were recorded. Force measures were normalized to body mass, and sEMG amplitudes were normalized to a resting period. The group with CAI demonstrated less force when compared to the control group ( P < .001) in both the neutral and plantarflexion positions: neutral position, CAI: 1.64 Nm/kg and control: 2.10 Nm/kg) and plantarflexion position, CAI: 1.40 Nm/kg and control: 1.73 Nm/kg). There were no differences in sEMG amplitudes between the groups or muscles ( P > .05). Force measures correlated with both muscles' sEMG amplitudes in the healthy group (neutral peroneus longus: r = 0.42, P = .03; plantarflexion peroneus longus: r = 0.56, P = .002; neutral peroneus brevis: r = 0.38, P = .05; plantarflexion peroneus longus: r = 0.40, P = .04), but not in the group with CAI ( P > .05). The group with CAI generated less force when compared to the control group during both testing positions. There was no selective activation of the peroneal muscles with testing in both positions, and force output and sEMG activity was only related in the healthy group. Clinicians should assess eversion strength and implement strength training exercises in different sagittal plane positions and evaluate for other pathologies that may contribute to reduced eversion strength in patients with CAI. Level III, cross-sectional.

Pion distribution amplitude and quasidistributions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Radyushkin, Anatoly V.

2017-03-27

We extend our analysis of quasidistributions onto the pion distribution amplitude. Using the formalism of parton virtuality distribution amplitudes, we establish a connection between the pion transverse momentum dependent distribution amplitude Ψ(x,k 2 ⊥) and the pion quasidistribution amplitude (QDA) Q π(y,p 3). We build models for the QDAs from the virtuality-distribution-amplitude-based models for soft transverse momentum dependent distribution amplitudes, and analyze the p3 dependence of the resulting QDAs. As there are many models claimed to describe the primordial shape of the pion distribution amplitude, we present the p 3-evolution patterns for models producing some popular proposals: Chernyak-Zhitnitsky, flat, andmore » asymptotic distribution amplitude. Finally, our results may be used as a guide for future studies of the pion distribution amplitude on the lattice using the quasidistribution approach.« less

The event-related potential component P3a is diminished by identical deviance repetition, but not by non-identical repetitions.

PubMed

Rosburg, Timm; Weigl, Michael; Thiel, Ronja; Mager, Ralph

2018-05-01

Mismatch negativity (MMN) represents an event-related potential (ERP) component which is elicited by deviant sound events in an otherwise regular, repetitive stimulation. The MMN amplitude typically decreases when two identical deviants are presented in direct succession, but it remains stable when the two deviants vary from the standard in different features. Less is known about such repetition effects on another ERP component, the P3a, which usually follows the MMN. In the current study, we investigated how the P3a was affected by identical and non-identical repetitions of sound deviants. The ERP analysis revealed that the P3a amplitudes were strongly diminished when the repeated deviants were identical, but the P3a remained stable when the repeated deviants varied. The findings suggest that not only the deviance detection system, as reflected in the MMN, but also subsequent attention switch systems, as reflected in the P3a, operate independently across different sound features.

Electron-impact ionization of Ne (2 p ) and Ar (3 p ) at intermediate energies: Role of the postcollision interaction

NASA Astrophysics Data System (ADS)

Hu, Xiaoqing; Gao, Cong-Zhang; Chen, Zhanbin; Wang, Jianguo; Wu, Yong; Wang, Yang

2017-11-01

We present the absolute triple differential cross section (TDCS) for single ionization of Ne (2 p ) at an impact energy of 599.6 eV and Ar (3 p ) at 195 eV. The role of the postcollision interaction (PCI) is studied using a high-order distorted-wave Born approximation model with a continuum distorted-waves expansion. Both the second- and third-order effects are considered in the present calculations, and the third-order distorted wave Born approximation model is reported in the (e ,2 e ) reaction. The calculated results show satisfactory agreement with experimental data. The magnitude of the absolute TDCS is enhanced by a factor 2-3 when the strength factor γ of the PCI amplitude is summarized just from 0 to 2. This proves that the PCI plays an important role in the absolute TDCS of the (e ,2 e ) reaction in the intermediate-energy region.

Assessment of pilot workload - Converging measures from performance based, subjective and psychophysiological techniques

NASA Technical Reports Server (NTRS)

Kramer, Arthur F.; Sirevaag, Erik J.; Braune, Rolf

1986-01-01

This study explores the relationship between the P300 component of the event-related brain potential (ERP) and the processing demands of a complex real-world task. Seven male volunteers enrolled in an Instrument Flight Rule (IFR) aviation course flew a series of missions in a single engine fixed-based simulator. In dual task conditions subjects were also required to discriminate between two tones differing in frequency. ERPs time-locked to the tones, subjective effort ratings and overt performance measures were collected during two 45 min flights differing in difficulty (manipulated by varying both atmospheric conditions and instrument reliability). The more difficult flight was associated with poorer performance, increased subjective effort ratings, and smaller secondary task P300s. Within each flight, P300 amplitude was negatively correlated with deviations from command headings indicating that P300 amplitude was a sensitive workload metric both between and within the flight missions.

Intelligence and information processing during a visual search task in children: an event-related potential study.

PubMed

Zhang, Qiong; Shi, Jiannong; Luo, Yuejia; Zhao, Daheng; Yang, Jie

2006-05-15

To investigate the differences in event-related potential parameters related to children's intelligence, we selected 15 individuals from an experimental class of intellectually gifted children and 13 intellectually average children as control to finish three types of visual search tasks (Chinese words, English letters and Arabic numbers). We recorded the electroencephalogram and calculated the peak latencies and amplitudes. Our results suggest comparatively increased P3 amplitudes and shorter P3 latencies in brighter individuals than in less intelligent individuals, but this expected neural efficiency effect interacted with task content. The differences were explained by a more spatially and temporally coordinated neural network for more intelligent children.

Core Muscle Activity during TRX Suspension Exercises with and without Kinesiology Taping in Adults with Chronic Low Back Pain: Implications for Rehabilitation.

PubMed

Fong, Shirley S M; Tam, Y T; Macfarlane, Duncan J; Ng, Shamay S M; Bae, Young-Hyeon; Chan, Eleanor W Y; Guo, X

2015-01-01

This study aimed to examine the effects of kinesiology taping (KT) and different TRX suspension workouts on the amplitude of electromyographic (EMG) activity in the core muscles among people with chronic low back pain (LBP). Each participant (total n = 21) was exposed to two KT conditions: no taping and taping, while performing four TRX suspension exercises: (1) hamstring curl, (2) hip abduction in plank, (3) chest press, and (4) 45-degree row. Right transversus abdominis/internal oblique (TrAIO), rectus abdominis (RA), external oblique (EO), and superficial lumbar multifidus (LMF) activity was recorded with surface EMG and expressed as a percentage of the EMG amplitude recorded during a maximal voluntary isometric contraction of the respective muscles. Hip abduction in plank increased TrAIO, RA, and LMF EMG amplitude compared with other TRX positions (P < 0.008). Only the hamstring curl was effective in inducing a high EMG amplitude of LMF (P < 0.001). No significant difference in EMG magnitude was found between the taping and no taping conditions overall (P > 0.05). Hip abduction in plank most effectively activated abdominal muscles, whereas the hamstring curl most effectively activated the paraspinal muscles. Applying KT conferred no immediate benefits in improving the core muscle activation during TRX training in adults with chronic LBP.

The Sex Differences in Regulating Unpleasant Emotion by Expressive Suppression: Extraversion Matters

PubMed Central

Cai, Ayan; Lou, Yixue; Long, Quanshan; Yuan, Jiajin

2016-01-01

Males are known for more suppression of emotional displays than females. However, when the emotion regulation effect of expressive suppression is greater in males, and how this sex difference varies with emotion display-related personality (e.g., extraversion), are undetermined. Event-related potentials were recorded while male and female participants different in extraversion were required to attend to or suppress emotional expression to negative pictures. Sex and extraversion did not modulate self-reported emotional experience. However, late positive potential (LPP) amplitudes showed an extraversion-moderated sex difference in the 2000–3000 ms and the 3000–4000 ms time epochs. LPP amplitudes were decreased during suppression versus viewing conditions in ambivert males, while this effect was absent in ambivert females. However, the LPP amplitudes of extraverts were similar for suppression and viewing conditions, irrespective of sex and timing. Regardless of early, middle, or late time windows, LPP amplitudes were positively related to self-reported emotion. These results suggest a male advantage for using expressive suppression for emotion regulation in non-extraverted, ambivert individuals. PMID:27458408

The Sex Differences in Regulating Unpleasant Emotion by Expressive Suppression: Extraversion Matters.

PubMed

Cai, Ayan; Lou, Yixue; Long, Quanshan; Yuan, Jiajin

2016-01-01

Males are known for more suppression of emotional displays than females. However, when the emotion regulation effect of expressive suppression is greater in males, and how this sex difference varies with emotion display-related personality (e.g., extraversion), are undetermined. Event-related potentials were recorded while male and female participants different in extraversion were required to attend to or suppress emotional expression to negative pictures. Sex and extraversion did not modulate self-reported emotional experience. However, late positive potential (LPP) amplitudes showed an extraversion-moderated sex difference in the 2000-3000 ms and the 3000-4000 ms time epochs. LPP amplitudes were decreased during suppression versus viewing conditions in ambivert males, while this effect was absent in ambivert females. However, the LPP amplitudes of extraverts were similar for suppression and viewing conditions, irrespective of sex and timing. Regardless of early, middle, or late time windows, LPP amplitudes were positively related to self-reported emotion. These results suggest a male advantage for using expressive suppression for emotion regulation in non-extraverted, ambivert individuals.

Effect of practicing yoga on cervical vestibular evoked myogenic potential.

PubMed

Shambhu, Tejaswini; Kumar, Shubhaganga Dhrruva; Prabhu, Prashanth

2017-10-01

The present study attempted to determine the effect of practicing yoga on functioning of sacculo-collic pathway using cervical vestibular evoked myogenic potential (cVEMP). cVEMP was recorded from 40 participants (20 who practice yoga regularly and 20 who do not practice yoga regularly). The differences in amplitude of P1, N1, P1-N1 complex, asymmetry ratio and latencies of P1 and N1 of cVEMP were compared between both the groups. The results of the study showed that there was a significant increase (p < 0.05) in the amplitude of P1, N1 and P1-N1 complex and a significant reduction in latency (p < 0.05) for experimental group. The asymmetry ratio in individuals who practice yoga was significantly lower (Mean = 6.73) compared to the control group (Mean = 19.13). Multivariate regression analyses suggested that the number of years of yoga practice significantly predicted the amplitude of P1-N1 complex (β = 0.70, p < 0.01) and amplitude ratio (β = 0.72, p < 0.01). Thus, practicing yoga improves postural control and strengthens the muscles and vestibular system leading to enhanced cVEMP responses. The plastic changes in the vestibular system and increased muscular strength because of constant practicing of yoga could have led to changes in cVEMP responses. However, further studies on a larger group of individuals are essential for better clinical applicability of the results.

On the use of airborne LiDAR for braided river monitoring and water surface delineation

NASA Astrophysics Data System (ADS)

Vetter, M.; Höfle, B.; Pfeifer, N.; Rutzinger, M.; Stötter, J.

2009-04-01

Airborne LiDAR is an established technology for Earth surface surveying. With LiDAR data sets it is possible to derive maps with different land use classes, which are important for hydraulic simulations. We present a 3D point cloud based method for automatic water surface delineation using single as well as multitemporal LiDAR data sets. With the developed method it is possible to detect the location of the water surface with high planimetric accuracy. The multitemporal analysis of different LiDAR data sets makes it possible to visualize, monitor and quantify the changes of the flow path of braided rivers as well as derived water surface land use classes. The reflection properties from laser beams (1064 nm wavelength) on water surfaces are characterized by strong absorption or specular reflection resulting in a dominance of low signal amplitude values and a high number of laser shot dropouts (i.e. non-recorded laser echoes). The occurrence of dropouts is driven by (i) the incidence angle, (ii) the surface reflectance and (iii) the roughness of the water body. The input data of the presented delineation method are the modeled dropouts and the point cloud attributes of geometry and signal amplitude. A terrestrial orthophoto is used to explore the point cloud in order to find proper information about the geometry and amplitude attributes that are characteristic for water surfaces. The delineation method is divided into five major steps. (a) We compute calibrated amplitude values by reducing the atmospheric, topographic influences and the scan geometry for each laser echo. (b) Then, the dropouts are modeled by using the information from the time stamps, the pulse repetition frequency, the inertial measurement unit and the GPS information of the laser shots and the airplane. The next step is to calculate the standard deviation of the heights for all reflections and all modeled dropouts (c) in a specific radius around the points. (d) We compute the amplitude ratio density for all shots. The amplitude density ratio is the relation between the number of laser echoes having an amplitude within a specific interval (i.e. very low amplitudes) plus the dropouts (i.e. with amplitude of zero) divided by the number of all laser shots in a fixed search distance of a point. (e) We classify each point in water or a non-water by using the attributes of (i) the standard deviation of the height and (ii) the amplitude density ratio. For validation, a terrestrial orthophoto is used, which was taken at the same time as the laser campaign. A major advantage of this new approach is the ability of a point cloud based delineation of water and non-water areas. We demonstrate the results at the glacier forefield of the Hintereisferner (Ötztal, Tyrol, Austria) with multitemporal data sets. The multitemporal analysis demonstrates the strength of the delineation method for mapping the watercourse and monitoring the changes in the flow path of the braided river between the different epochs.

Effect of Floquet engineering on the p-wave superconductor with second-neighbor couplings

NASA Astrophysics Data System (ADS)

Li, X. P.; Li, C. F.; Wang, L. C.; Zhou, L.

2018-06-01

The influence of the Floquet engineering on a particular one-dimensional p-wave superconductor, Kitaev model, with second-neighbor couplings is investigated in this paper. The effective Hamiltonians in the rotated reference frames have been obtained, and the convergent regions of the approximated Hamiltonian as well as the topological phase diagrams have been analyzed and discussed. We show that by modulating the external driving field amplitude, frequency as well as the second-neighbor hopping amplitude, the rich phase diagrams and transitions between different topological phases can be obtained.

The relationship between accommodative amplitude and the ratio of central lens thickness to its equatorial diameter in vertebrate eyes

PubMed Central

Schachar, Ronald A; Pierscionek, Barbara K; Abolmaali, Ali; Le, Tri

2007-01-01

Aim To determine the relationship between accommodative amplitude and central lens thickness/equatorial lens diameter (CLT/ELD) ratio in vertebrates. Methods Midsagittal sections of lenses from fixed, post mortem eyes from 125 different vertebrate species were photographed. Their CLT/ELD ratios were correlated with independently published measurements of their accommodative amplitudes. Using the non‐linear finite element method (FEM), the efficiency of zonular traction (the absolute change in central radius of curvature per unit force [|ΔCR|/F]) for model lenses with CLT/ELD ratios from 0.45 to 0.9 was determined. Results Vertebrates with CLT/ELD ratios ⩽0.6 have high accommodative amplitudes. Zonular traction was found to be most efficient for those model lenses having CLT/ELD ratios ⩽0.6. Conclusions Vertebrates with lenses that have CLT/ELD ratios ⩽0.6 – i.e. “long oval” shapes – have the greatest accommodative amplitudes; e.g. primates, diving birds and diurnal birds of prey. Vertebrates that have oval or spherical shaped lenses, like owls and most mammals, have low accommodative amplitudes. Zonular traction was found to be most efficient when applied to model lenses with CLT/ELD ratios ⩽0.6. The implications of these findings on the mechanism of accommodation are discussed. PMID:17050574

Development of a methodology to measure the effect of ergot alkaloids on forestomach motility using real-time wireless telemetry

NASA Astrophysics Data System (ADS)

Egert, Amanda; Klotz, James; McLeod, Kyle; Harmon, David

2014-10-01

The objectives of these experiments were to characterize rumen motility patterns of cattle fed once daily using a real-time wireless telemetry system, determine when to measure rumen motility with this system, and determine the effect of ruminal dosing of ergot alkaloids on rumen motility. Ruminally cannulated Holstein steers (n = 8) were fed a basal diet of alfalfa cubes once daily. Rumen motility was measured by monitoring real-time pressure changes within the rumen using wireless telemetry and pressure transducers. Experiment 1 consisted of three 24-h rumen pressure collections beginning immediately after feeding. Data were recorded, stored, and analyzed using iox2 software and the rhythmic analyzer. All motility variables differed (P < 0.01) between hours and thirds (8-h periods) of the day. There were no differences between days for most variables. The variance of the second 8-h period of the day was less than (P < 0.01) the first for area and less than the third for amplitude, frequency, duration, and area (P < 0.05). These data demonstrated that the second 8-h period of the day was the least variable for many measures of motility and would provide the best opportunity for testing differences in motility due to treatments. In Exp. 2, the steers (n = 8) were pair-fed the basal diet of Exp. 1 and dosed with endophyte-free (E-) or endophyte-infected (E+; 0 or 10 μg ergovaline + ergovalinine / kg BW; respectively) tall fescue seed before feeding for 15 d. Rumen motility was measured for 8 h beginning 8 h after feeding for the first 14 d of seed dosing. Blood samples were taken on d 1, 7, and 15, and rumen content samples were taken on d 15. Baseline (P = 0.06) and peak (P = 0.04) pressure were lower for E+ steers. Water intake tended (P = 0.10) to be less for E+ steers the first 8 hour period after feeding. The E+ seed treatment at this dosage under thermoneutral conditions did not significantly affect rumen motility, ruminal fill, or dry matter of rumen contents.

Seismic amplitude measurements suggest foreshocks have different focal mechanisms than aftershocks

USGS Publications Warehouse

Lindh, A.; Fuis, G.; Mantis, C.

1978-01-01

The ratio of the amplitudes of P and S waves from the foreshocks and aftershocks to three recent California earthquakes show a characteristic change at the time of the main events. As this ratio is extremely sensitive to small changes in the orientation of the fault plane, a small systematic change in stress or fault configuration in the source region may be inferred. These results suggest an approach to the recognition of foreshocks based on simple measurements of the amplitudes of seismic waves. Copyright ?? 1978 AAAS.

Combustion Stability Characteristics of the Project Morpheus Liquid Oxygen/Liquid Methane Main Engine

NASA Technical Reports Server (NTRS)

Melcher, J. C.; Morehead, Robert L.

2014-01-01

The Project Morpheus liquid oxygen (LOX) / liquid methane rocket engines demonstrated acousticcoupled combustion instabilities during sea-level ground-based testing at the NASA Johnson Space Center (JSC) and Stennis Space Center (SSC). High-amplitude, 1T, 1R, 1T1R (and higher order) modes appear to be triggered by injector conditions. The instability occurred during the Morpheus-specific engine ignition/start sequence, and did demonstrate the capability to propagate into mainstage. However, the instability was never observed to initiate during mainstage, even at low power levels. The Morpheus main engine is a JSC-designed 5,000 lbf-thrust, 4:1 throttling, pressure-fed cryogenic engine using an impinging element injector design. Two different engine designs, named HD4 and HD5, and two different builds of the HD4 engine all demonstrated similar instability characteristics. Through the analysis of more than 200 hot fire tests on the Morpheus vehicle and SSC test stand, a relationship between ignition stability and injector/chamber pressure was developed. The instability has the distinct characteristic of initiating at high relative injection pressure drop (dP) at low chamber pressure (Pc); i.e., instabilities initiated at high dP/Pc at low Pc during the start sequence. The high dP/Pc during start results during the injector /chamber chill-in, and is enhanced by hydraulic flip in the injector orifice elements. Because of the fixed mixture ratio of the existing engine design (the main valves share a common actuator), it is not currently possible to determine if LOX or methane injector dP/Pc were individual contributors (i.e., LOX and methane dP/Pc typically trend in the same direction within a given test). The instability demonstrated initiation characteristic of starting at or shortly after methane injector chillin. Colder methane (e.g., sub-cooled) at the injector inlet prior to engine start was much more likely to result in an instability. A secondary effect of LOX sub-cooling was also possibly observed; greater LOX sub- cooling improved stability. Some tests demonstrated a low-amplitude 1L-1T instability prior to LOX injector chill-in. The Morpheus main engine also demonstrated chug instabilities during some engine shutdown sequences on the flight vehicle and SSC test stand. The chug instability was also infrequently observed during the startup sequence. The chug instabilities predictably initiated at low dP/Pc at low Pc. The chug instabilities were always self-limiting; startup chug instabilities terminated during throttle-up and shutdown chug instabilities decayed by shutdown termination.

Prolongation of ERP latency and reaction time (RT) in simultaneous EEG/fMRI data acquisition.

PubMed

Chun, Jinsoo; Peltier, Scott J; Yoon, Daehyun; Manschreck, Theo C; Deldin, Patricia J

2016-08-01

Recording EEG and fMRI data simultaneously inside a fully-operating scanner has been recognized as a novel approach in human brain research. Studies have demonstrated high concordance between the EEG signals and hemodynamic response. However, a few studies reported altered cognitive process inside the fMRI scanner such as delayed reaction time (RT) and reduced and/or delayed N100 and P300 event-related brain potential (ERP) components. The present study investigated the influence of electromagnetic field (static magnetic field, radio frequency (RF) pulse, and gradient switching) and experimental environment on posterior N100 and P300 ERP components in four different settings with six healthy subjects using a visual oddball task: (1) classic fMRI acquisition inside the scanner (e.g., supine position, mirror glasses for stimulus presentation), (2) standard behavioral experiment outside the scanner (e.g., seated position, keyboard response), (3) controlled fMRI acquisition inside the scanner (e.g., organic light-emitting diode (OLED) goggles for stimulus presentation) inside; and (4) modified behavioral experiment outside the scanner (e.g., supine position, OLED goggles). The study findings indicated that the experimental environment in simultaneous EEG/fMRI acquisition could substantially delay N1P, P300 latency, and RT inside the scanner, and was associated with a reduced N1P amplitude. There was no effect of electromagnetic field in the prolongation of RT, N1P and P300 latency inside the scanner. N1P, but not P300, latency was sensitive to stimulus presentation method inside the scanner. Future simultaneous EEG/fMRI data collection should consider experimental environment in both design and analysis. Copyright © 2016 Elsevier B.V. All rights reserved.

Reynolds number effects on the single-mode Richtmyer-Meshkov instability

NASA Astrophysics Data System (ADS)

Walchli, B.; Thornber, B.

2017-01-01

The Reynolds number effects on the nonlinear growth rates of the Richtmyer-Meshkov instability are investigated using two-dimensional numerical simulations. A decrease in Reynolds number gives an increased time to reach nonlinear saturation, with Reynolds number effects only significant in the range Re<256 . Within this range there is a sharp change in instability properties. The bubble and spike amplitudes move towards equal size at lower Reynolds numbers and the bubble velocities decay faster than predicted by Sohn's model [S.-I. Sohn, Phys. Rev. E 80, 055302 (2009), 10.1103/PhysRevE.80.055302]. Predicted amplitudes show reasonable agreement with the existing theory of Carles and Popinet [P. Carles and S. Popinet, Phys. Fluids Lett. 13, 1833 (2001), 10.1063/1.1377863; Eur. J. Mech. B 21, 511 (2002), 10.1016/S0997-7546(02)01199-8] and Mikaelian [K. O. Mikaelian, Phys. Rev. E 47, 375 (1993), 10.1103/PhysRevE.47.375; K. O. Mikaelian, Phys. Rev. E 87, 031003 (2013), 10.1103/PhysRevE.87.031003], with the former being the closest match to the current computations.

The relationship between maximum tolerated light intensity and photoprotective energy dissipation in the photosynthetic antenna: chloroplast gains and losses

PubMed Central

Ruban, Alexander V.; Belgio, Erica

2014-01-01

The principle of quantifying the efficiency of protection of photosystem II (PSII) reaction centres against photoinhibition by non-photochemical energy dissipation (NPQ) has been recently introduced by Ruban & Murchie (2012 Biochim. Biophys. Acta 1817, 977–982 (doi:10.1016/j.bbabio.2012.03.026)). This is based upon the assessment of two key parameters: (i) the relationship between the PSII yield and NPQ, and (ii) the fraction of intact PSII reaction centres in the dark after illumination. In this paper, we have quantified the relationship between the amplitude of NPQ and the light intensity at which all PSII reaction centres remain intact for plants with different levels of PsbS protein, known to play a key role in the process. It was found that the same, nearly linear, relationship exists between the levels of the protective NPQ component (pNPQ) and the tolerated light intensity in all types of studied plants. This approach allowed for the quantification of the maximum tolerated light intensity, the light intensity at which all plant leaves become photoinhibited, the fraction of (most likely) unnecessary or ‘wasteful’ NPQ, and the fraction of photoinhibited PSII reaction centres under conditions of prolonged illumination by full sunlight. It was concluded that the governing factors in the photoprotection of PSII are the level and rate of protective pNPQ formation, which are often in discord with the amplitude of the conventional measure of photoprotection, the quickly reversible NPQ component, qE. Hence, we recommend pNPQ as a more informative and less ambiguous parameter than qE, as it reflects the effectiveness and limitations of the major photoprotective process of the photosynthetic membrane. PMID:24591709

Schwann Cells in Neuromuscular Junction Formation and Maintenance.

PubMed

Barik, Arnab; Li, Lei; Sathyamurthy, Anupama; Xiong, Wen-Cheng; Mei, Lin

2016-09-21

The neuromuscular junction (NMJ) is a tripartite synapse that is formed by motor nerve terminals, postjunctional muscle membranes, and terminal Schwann cells (TSCs) that cover the nerve-muscle contact. NMJ formation requires intimate communications among the three different components. Unlike nerve-muscle interaction, which has been well characterized, less is known about the role of SCs in NMJ formation and maintenance. We show that SCs in mice lead nerve terminals to prepatterned AChRs. Ablating SCs at E8.5 (i.e., prior nerve arrival at the clusters) had little effect on aneural AChR clusters at E13.5, suggesting that SCs may not be necessary for aneural clusters. SC ablation at E12.5, a time when phrenic nerves approach muscle fibers, resulted in smaller and fewer nerve-induced AChR clusters; however, SC ablation at E15.5 reduced AChR cluster size but had no effect on cluster density, suggesting that SCs are involved in AChR cluster maturation. Miniature endplate potential amplitude, but not frequency, was reduced when SCs were ablated at E15.5, suggesting that postsynaptic alterations may occur ahead of presynaptic deficits. Finally, ablation of SCs at P30, after NMJ maturation, led to NMJ fragmentation and neuromuscular transmission deficits. Miniature endplate potential amplitude was reduced 3 d after SC ablation, but both amplitude and frequency were reduced 6 d after. Together, these results indicate that SCs are not only required for NMJ formation, but also necessary for its maintenance; and postsynaptic function and structure appeared to be more sensitive to SC ablation. Neuromuscular junctions (NMJs) are critical for survival and daily functioning. Defects in NMJ formation during development or maintenance in adulthood result in debilitating neuromuscular disorders. The role of Schwann cells (SCs) in NMJ formation and maintenance was not well understood. We genetically ablated SCs during development and after NMJ formation to investigate the consequences of the ablation. This study reveals a critical role of SCs in NMJ formation as well as maintenance. Copyright © 2016 the authors 0270-6474/16/369770-12$15.00/0.

Normative data for Aδ contact heat evoked potentials in adult population: a multicenter study.

PubMed

Granovsky, Yelena; Anand, Praveen; Nakae, Aya; Nascimento, Osvaldo; Smith, Benn; Sprecher, Elliot; Valls-Solé, Josep

2016-05-01

There has been a significant increase over recent years in the use of contact heat evoked potentials (CHEPs) for the evaluation of small nerve fiber function. Measuring CHEP amplitude and latency has clinical utility for the diagnosis and assessment of conditions with neuropathic pain. This international multicenter study aimed to provide reference values for CHEPs to stimuli at 5 commonly examined body sites. Contact heat evoked potentials were recorded from 226 subjects (114 females), distributed per age decade between 20 and 79 years. Temperature stimuli were delivered by a thermode (32°C-51°C at a rate of 70°C/s). In phase I of the study, we investigated side-to-side differences and reported the maximum normal side-to-side difference in Aδ CHEP peak latency and amplitude for leg, forearm, and face. In phase II, we obtained normative data for 3 CHEP parameters (N2P2 amplitude, N2 latency, and P2 latency), stratified for gender and age decades from face, upper and lower limbs, and overlying cervical and lumbar spine. In general, larger CHEP amplitudes were associated with higher evoked pain scores. Females had CHEPs of larger amplitude and shorter latency than males. This substantive data set of normative values will facilitate the clinical use of CHEPs as a rapid, noninvasive, and objective technique for the assessment of patients presenting with neuropathic pain.

[Binocular status of dyslexics--are there differences to a healthy comparison group?].

PubMed

Riebeling, P; Brunner, E; Grossjohann, R; Clemens, S

2009-10-01

Despite numerous studies dealing with the question of a possible relation of visual problems and dyslexia, which is negated by most ophthalmologists, some opticians still favour the treatment of dyslexia by correction of the "Winkelfehlsichtigkeit" following MCH. Our aim was by also including the Pola test to check the usefulness of this treatment. In a 2-year prospective study we examined the 4th grade elementary school students in our city who had dyslexia as an assured diagnosis (n = 21). The results were compared to those of an age-matched group without pathological findings regarding their reading and spelling ability (n = 21). Examinations included visual acuity, eye position by cover test, Maddox cylinder and Pola test for near distance, binocular vision (Bagolini and Worth test, Lang test I and II, Titmus test, amplitude of fusion), amplitude of accommodation, refraction in cycloplegia and organic status. A significant difference was found between the two groups regarding the amplitude of divergence in near (p = 0.009) and far distance (p = 0.019) which were both smaller for the dyslexia group, as well as the binocular near visual acuity (p = 0.04). Using the SAS procedure STEPDISC we discriminated the normal and dyslexia group by amplitude of divergence, near visual acuity and alternating near prism cover test with a sensitivity of 81 % and a specifity of 75 %. The results of the Pola test did not show any significant difference between the groups. No differences were found between the groups regarding the eye position. Therefore a treatment of dyslexia using prisms does not appear reasonable. However because of the group sizes the significance of the results is limited. Georg Thieme Verlag KG Stuttgart.New York.

4D CT amplitude binning for the generation of a time-averaged 3D mid-position CT scan

NASA Astrophysics Data System (ADS)

Kruis, Matthijs F.; van de Kamer, Jeroen B.; Belderbos, José S. A.; Sonke, Jan-Jakob; van Herk, Marcel

2014-09-01

The purpose of this study was to develop a method to use amplitude binned 4D-CT (A-4D-CT) data for the construction of mid-position CT data and to compare the results with data created from phase-binned 4D-CT (P-4D-CT) data. For the latter purpose we have developed two measures which describe the regularity of the 4D data and we have tried to correlate these measures with the regularity of the external respiration signal. 4D-CT data was acquired for 27 patients on a combined PET-CT scanner. The 4D data were reconstructed twice, using phase and amplitude binning. The 4D frames of each dataset were registered using a quadrature-based optical flow method. After registration the deformation vector field was repositioned to the mid-position. Since amplitude-binned 4D data does not provide temporal information, we corrected the mid-position for the occupancy of the bins. We quantified the differences between the two mid-position datasets in terms of tumour offset and amplitude differences. Furthermore, we measured the standard deviation of the image intensity over the respiration after registration (σregistration) and the regularity of the deformation vector field (\\overline{\\Delta |J|} ) to quantify the quality of the 4D-CT data. These measures were correlated to the regularity of the external respiration signal (σsignal). The two irregularity measures, \\overline{\\Delta |J|} and σregistration, were dependent on each other (p < 0.0001, R2 = 0.80 for P-4D-CT, R2 = 0.74 for A-4D-CT). For all datasets amplitude binning resulted in lower \\overline{\\Delta |J|} and σregistration and large decreases led to visible quality improvements in the mid-position data. The quantity of artefact decrease was correlated to the irregularity of the external respiratory signal. The average tumour offset between the phase and amplitude binned mid-position without occupancy correction was 0.42 mm in the caudal direction (10.6% of the amplitude). After correction this was reduced to 0.16 mm in caudal direction (4.1% of the amplitude). Similar relative offsets were found at the diaphragm. We have devised a method to use amplitude binned 4D-CT to construct motion model and generate a mid-position planning CT for radiotherapy treatment purposes. We have decimated the systematic offset of this mid-position model with a motion model derived from P-4D-CT. We found that the A-4D-CT led to a decrease of local artefacts and that this decrease was correlated to the irregularity of the external respiration signal.

An Investigation of the Effects of Different Pulse Patterns of Transcutaneous Electrical Nerve Stimulation (TENS) on Perceptual Embodiment of a Rubber Hand in Healthy Human Participants With Intact Limbs.

PubMed

Mulvey, Matthew R; Fawkner, Helen J; Johnson, Mark I

2015-12-01

The aim of this study was to investigate the strength of perceptual embodiment achieved during an adapted version of the rubber hand illusion (RHI) in response to a series of modified transcutaneous electrical nerve stimulation (TENS) pulse patterns with dynamic temporal and spatial characteristics which are more akin to the mechanical brush stroke in the original RHI. A repeated-measures counterbalanced experimental study was conducted where each participant was exposed to four TENS interventions: continuous pattern TENS; burst pattern TENS (fixed frequency of 2 bursts per second of 100 pulses per second); amplitude-modulated pattern TENS (intensity increasing from zero to a preset level, then back to zero again in a cyclical fashion); and sham (no current) TENS. Participants rated the intensity of the RHI using a three-item numerical rating scale (each item was ranked from 0 to 10). Friedman's analysis of ranks (one-factor repeated measure) was used to test the differences in perceptual embodiment between TENS innervations; alpha was set at p ≤ 0.05. There were statistically significant differences in the intensity of misattribution and perceptual embodiment between sham and active TENS interventions, but no significant differences between the three active TENS conditions (amplitude-modulated TENS, burst TENS, and continuous TENS). Amplitude-modulated and burst TENS produced significantly higher intensity scores for misattribution sensation and perceptual embodiment compared with sham (no current) TENS, whereas continuous TENS did not. The findings provide tentative, but not definitive, evidence that TENS parameters with dynamic spatial and temporal characteristics may produce more intense misattribution sensations and intense perceptual embodiment than parameters with static characteristics (e.g., continuous pulse patterns). © 2015 International Neuromodulation Society.

Central neuronal motor behaviour in skilled and less skilled novices - Approaching sports-specific movement techniques.

PubMed

Vogt, Tobias; Kato, Kouki; Schneider, Stefan; Türk, Stefan; Kanosue, Kazuyuki

2017-04-01

Research on motor behavioural processes preceding voluntary movements often refers to analysing the readiness potential (RP). For this, decades of studies used laboratory setups with controlled sports-related actions. Further, recent applied approaches focus on athlete-non-athlete comparisons, omitting possible effects of training history on RP. However, RP preceding real sport-specific movements in accordance to skill acquisition remains to be elucidated. Therefore, after familiarization 16 right-handed males with no experience in archery volunteered to perform repeated sports-specific movements, i.e. 40 arrow-releasing shots at 60s rest on a 15m distant standard target. Continuous, synchronised EEG and right limb EMG recordings during arrow-releasing served to detect movement onsets for RP analyses over distinct cortical motor areas. Based on attained scores on target, archery novices were, a posteriori, subdivided into a skilled and less skilled group. EMG results for mean values revealed no significant changes (all p>0.05), whereas RP amplitudes and onsets differed between groups but not between motor areas. Arrow-releasing preceded larger RP amplitudes (p<0.05) and later RP onsets (p<0.05) in skilled compared to less skilled novices. We suggest this to reflect attentional orienting and greater effort that accompanies central neuronal preparatory states of a sports-specific movement. Copyright © 2017 Elsevier B.V. All rights reserved.

Testing neurophysiological markers related to fear-potentiated startle.

PubMed

Seligowski, Antonia V; Bondy, Erin; Singleton, Paris; Orcutt, Holly K; Ressler, Kerry J; Auerbach, Randy P

2018-06-11

Fear-potentiated startle (FPS) paradigms provide insight into fear learning mechanisms that contribute to impairment among individuals with posttraumatic stress symptoms (PTSS). Electrophysiology also has provided insight into these mechanisms through the examination of event-related potentials (ERPs) such as the P100 and LPP. It remains unclear, however, whether the P100 and LPP may be related to fear learning processes within the FPS paradigm. To this end, we tested differences in ERP amplitudes for conditioned stimuli associated (CS+) and not associated (CS-) with an aversive unconditioned stimulus (US) during fear acquisition. Participants included 54 female undergraduate students (mean age = 20.26). The FPS response was measured via electromyography of the orbicularis oculi muscle. EEG data were collected during the FPS paradigm. While the difference between CS+ and CS- P100 amplitude was not significant, LPP amplitudes were significantly enhanced following the CS+ relative to CS-. Furthermore, the LPP difference wave (CS+ minus CS-) was associated with FPS scores for the CS- during the later portion of fear acquisition. These findings suggest that conditioned stimuli may have altered emotional encoding (LPP) during the FPS paradigm. Thus, the LPP may be a promising neurophysiological marker that is related to fear learning processes. Copyright © 2018 Elsevier B.V. All rights reserved.

Can working memory predict target-to-target interval effects in the P300?

PubMed

Steiner, Genevieve Z; Barry, Robert J; Gonsalvez, Craig J

2013-09-01

It has been suggested that the P300 component of the ERP is an electrophysiological index of memory-updating processes associated with task-relevant stimuli. Component magnitude varies with the time separating target stimuli (target-to-target interval: TTI), with longer TTIs eliciting larger P300 amplitudes. According to the template-update perspective, TTI effects observable in the P300 reflect the updating of stimulus-templates in working memory (WM). The current study explored whether young adults' memory-task ability could predict TTI effects in P300. EEG activity was recorded from 50 university students (aged 18-25 years) while they completed an auditory equiprobable Go/NoGo task with manipulations of TTIs. Participants also completed a CogState® battery and were sorted according to their WM score. ERPs were analysed using a temporal PCA. Two P300 components, P3b and the Slow Wave, were found to linearly increase in amplitude to longer TTIs. This TTI effect differed between groups only for the P3b component: The high WM group showed a steeper increase in P3b amplitude with TTI than the low WM group. These results suggest that TTI effects in P300 are directly related to WM processes. © 2013.

Association among parental substance use disorder, p300 amplitude, and neurobehavioral disinhibition in preteen boys at high risk for substance use disorder.

PubMed

Habeych, Miguel E; Sclabassi, Robert J; Charles, Prophete J; Kirisci, Levent; Tarter, Ralph E

2005-06-01

The P300 amplitude of the event-related potential as a mediator of the association between parental substance use disorder (SUD) and child's neurobehavioral disinhibition was assessed. The P300 amplitude was recorded using an oddball task in sons of fathers having either lifetime SUD (n = 105) or no psychiatric disorder (n = 160). Neurobehavioral disinhibition was assessed using measures of affect regulation, behavior control, and executive cognitive function. Parental SUD and child's P300 amplitude accounted for, respectively, 16.6% and 16.8% of neurobehavioral disinhibition variance. Controlling for parental and child psychopathology, an association between parental SUD and child's P300 amplitude was not observed. It was concluded that the P300 amplitude does not mediate the association between parental SUD and child's neurobehavioral disinhibition. Copyright 2005 APA, all rights reserved.

Electroexcitation of the Δ +(1232) at low momentum transfer

DOE PAGES

Blomberg, A.; Anez, D.; Sparveris, N.; ...

2016-07-05

We report on new pmore » $$(e,e^\\prime p)\\pi^\\circ$$ measurements at the $$\\Delta^{+}(1232)$$ resonance at the low momentum transfer region. The mesonic cloud dynamics is predicted to be dominant and rapidly changing in this kinematic region offering a test bed for chiral effective field theory calculations. The new data explore the low $Q^2$ dependence of the resonant quadrupole amplitudes while extending the measurements of the Coulomb quadrupole amplitude to the lowest momentum transfer ever reached. The results disagree with predictions of constituent quark models and are in reasonable agreement with dynamical calculations that include pion cloud effects, chiral effective field theory and lattice calculations. The reported measurements suggest that improvement is required to the theoretical calculations and provide valuable input that will allow their refinements.« less

Reward and punishment hyposensitivity in problem gamblers: A study of event-related potentials using a principal components analysis.

PubMed

Lole, Lisa; Gonsalvez, Craig J; Barry, Robert J

2015-07-01

To investigate whether the latent neural correlates of incentive processing differ between problem gamblers (PGs) and healthy controls (HCs). Event-related potential (ERP) data were derived while 16 PGs and 20 HCs played a computer electronic gaming machine (EGM) task. Psychophysiological responses to outcomes commonly encountered during EGM gambling, including Large wins, Small wins, Near-wins, and Losses, were examined using a spatiotemporal principal components analysis (PCA). Subjects also completed questionnaires that assessed their levels of impulsivity, attraction to appetitive stimuli, and avoidance of aversive stimuli. Losses elicited a feedback-related negativity (FRN), whereas wins elicited a feedback-related positivity (FRP) at the same latency and topography. PGs exhibited both attenuated FRN amplitudes following Losses and FRP amplitudes following Wins. Greater P3b amplitudes were found following Wins compared to Losses. FRN amplitudes following Near-wins were significantly reduced compared to Losses for both PGs and HCs. Trends for reduced P3b amplitudes following all outcome types, and for similar P3b amplitudes following Large and Small wins, were found for the PG group. We provide evidence that PGs are hyposensitive to both positive and negative outcomes. The finding that PGs are hyposensitive to reward and punishment provides valuable insight into the nature of deficit in this disorder, and provides a foundation for future research and clinical interventions. Copyright © 2014 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.

SU-E-J-227: Breathing Pattern Consistency and Reproducibility: Comparative Analysis for Supine and Prone Body Positioning

DOE Office of Scientific and Technical Information (OSTI.GOV)

Laugeman, E; Weiss, E; Chen, S

2014-06-01

Purpose: Evaluate and compare the cycle-to-cycle consistency of breathing patterns and their reproducibility over the course of treatment, for supine and prone positioning. Methods: Respiratory traces from 25 patients were recorded for sequential supine/prone 4DCT scans acquired prior to treatment, and during the course of the treatment (weekly or bi-weekly). For each breathing cycle, the average(AVE), end-of-exhale(EoE) and end-of-inhale( EoI) locations were identified using in-house developed software. In addition, the mean values and variations for the above quantities were computed for each breathing trace. F-tests were used to compare the cycle-to-cycle consistency of all pairs of sequential supine and pronemore » scans. Analysis of variances was also performed using population means for AVE, EoE and EoI to quantify differences between the reproducibility of prone and supine respiration traces over the treatment course. Results: Consistency: Cycle-to-cycle variations are less in prone than supine in the pre-treatment and during-treatment scans for AVE, EoE and EoI points, for the majority of patients (differences significant at p<0.05). The few cases where the respiratory pattern had more variability in prone appeared to be random events. Reproducibility: The reproducibility of breathing patterns (supine and prone) improved as treatment progressed, perhaps due to patients becoming more comfortable with the procedure. However, variability in supine position continued to remain significantly larger than in prone (p<0.05), as indicated by the variance analysis of population means for the pretreatment and subsequent during-treatment scans. Conclusions: Prone positioning stabilizes breathing patterns in most subjects investigated in this study. Importantly, a parallel analysis of the same group of patients revealed a tendency towards increasing motion amplitude of tumor targets in prone position regardless of their size or location; thus, the choice for body positioning during radiation therapy will have to consider the clinical relevance of the two opposing trends - breathing consistency and motion amplitude.« less

Cross-Modal and Intra-Modal Characteristics of Visual Function and Speech Perception Performance in Postlingually Deafened, Cochlear Implant Users

PubMed Central

Kim, Min-Beom; Shim, Hyun-Yong; Jin, Sun Hwa; Kang, Soojin; Woo, Jihwan; Han, Jong Chul; Lee, Ji Young; Kim, Martha; Cho, Yang-Sun

2016-01-01

Evidence of visual-auditory cross-modal plasticity in deaf individuals has been widely reported. Superior visual abilities of deaf individuals have been shown to result in enhanced reactivity to visual events and/or enhanced peripheral spatial attention. The goal of this study was to investigate the association between visual-auditory cross-modal plasticity and speech perception in post-lingually deafened, adult cochlear implant (CI) users. Post-lingually deafened adults with CIs (N = 14) and a group of normal hearing, adult controls (N = 12) participated in this study. The CI participants were divided into a good performer group (good CI, N = 7) and a poor performer group (poor CI, N = 7) based on word recognition scores. Visual evoked potentials (VEP) were recorded from the temporal and occipital cortex to assess reactivity. Visual field (VF) testing was used to assess spatial attention and Goldmann perimetry measures were analyzed to identify differences across groups in the VF. The association of the amplitude of the P1 VEP response over the right temporal or occipital cortex among three groups (control, good CI, poor CI) was analyzed. In addition, the association between VF by different stimuli and word perception score was evaluated. The P1 VEP amplitude recorded from the right temporal cortex was larger in the group of poorly performing CI users than the group of good performers. The P1 amplitude recorded from electrodes near the occipital cortex was smaller for the poor performing group. P1 VEP amplitude in right temporal lobe was negatively correlated with speech perception outcomes for the CI participants (r = -0.736, P = 0.003). However, P1 VEP amplitude measures recorded from near the occipital cortex had a positive correlation with speech perception outcome in the CI participants (r = 0.775, P = 0.001). In VF analysis, CI users showed narrowed central VF (VF to low intensity stimuli). However, their far peripheral VF (VF to high intensity stimuli) was not different from the controls. In addition, the extent of their central VF was positively correlated with speech perception outcome (r = 0.669, P = 0.009). Persistent visual activation in right temporal cortex even after CI causes negative effect on outcome in post-lingual deaf adults. We interpret these results to suggest that insufficient intra-modal (visual) compensation by the occipital cortex may cause negative effects on outcome. Based on our results, it appears that a narrowed central VF could help identify CI users with poor outcomes with their device. PMID:26848755

Effect of Postural Control Demands on Early Visual Evoked Potentials during a Subjective Visual Vertical Perception Task in Adolescents with Idiopathic Scoliosis.

PubMed

Chang, Yi-Tzu; Meng, Ling-Fu; Chang, Chun-Ju; Lai, Po-Liang; Lung, Chi-Wen; Chern, Jen-Suh

2017-01-01

Subjective visual vertical (SVV) judgment and standing stability were separately investigated among patients with adolescent idiopathic scoliosis (AIS). Although, one study has investigated the central mechanism of stability control in the AIS population, the relationships between SVV, decreased standing stability, and AIS have never been investigated. Through event-related potentials (ERPs), the present study examined the effect of postural control demands (PDs) on AIS central mechanisms related to SVV judgment and standing stability to elucidate the time-serial stability control process. Thirteen AIS subjects (AIS group) and 13 age-matched adolescents (control group) aged 12-18 years were recruited. Each subject had to complete an SVV task (i.e., the modified rod-and-frame [mRAF] test) as a stimulus, with online electroencephalogram recording being performed in the following three standing postures: feet shoulder-width apart standing, feet together standing, and tandem standing. The behavioral performance in terms of postural stability (center of pressure excursion), SVV (accuracy and reaction time), and mRAF-locked ERPs (mean amplitude and peak latency of the P1, N1, and P2 components) was then compared between the AIS and control groups. In the behavioral domain, the results revealed that only the AIS group demonstrated a significantly accelerated SVV reaction time as the PDs increased. In the cerebral domain, significantly larger P2 mean amplitudes were observed during both feet shoulder-width-apart standing and feet together standing postures compared with during tandem standing. No group differences were noted in the cerebral domain. The results indicated that (1) during the dual-task paradigm, a differential behavioral strategy of accelerated SVV reaction time was observed in the AIS group only when the PDs increased and (2) the decrease in P2 mean amplitudes with the increase in the PD levels might be direct evidence of the competition for central processing attentional resources under the dual-task postural control paradigm.

Effect of Postural Control Demands on Early Visual Evoked Potentials during a Subjective Visual Vertical Perception Task in Adolescents with Idiopathic Scoliosis

PubMed Central

Chang, Yi-Tzu; Meng, Ling-Fu; Chang, Chun-Ju; Lai, Po-Liang; Lung, Chi-Wen; Chern, Jen-Suh

2017-01-01

Subjective visual vertical (SVV) judgment and standing stability were separately investigated among patients with adolescent idiopathic scoliosis (AIS). Although, one study has investigated the central mechanism of stability control in the AIS population, the relationships between SVV, decreased standing stability, and AIS have never been investigated. Through event-related potentials (ERPs), the present study examined the effect of postural control demands (PDs) on AIS central mechanisms related to SVV judgment and standing stability to elucidate the time-serial stability control process. Thirteen AIS subjects (AIS group) and 13 age-matched adolescents (control group) aged 12–18 years were recruited. Each subject had to complete an SVV task (i.e., the modified rod-and-frame [mRAF] test) as a stimulus, with online electroencephalogram recording being performed in the following three standing postures: feet shoulder-width apart standing, feet together standing, and tandem standing. The behavioral performance in terms of postural stability (center of pressure excursion), SVV (accuracy and reaction time), and mRAF-locked ERPs (mean amplitude and peak latency of the P1, N1, and P2 components) was then compared between the AIS and control groups. In the behavioral domain, the results revealed that only the AIS group demonstrated a significantly accelerated SVV reaction time as the PDs increased. In the cerebral domain, significantly larger P2 mean amplitudes were observed during both feet shoulder-width-apart standing and feet together standing postures compared with during tandem standing. No group differences were noted in the cerebral domain. The results indicated that (1) during the dual-task paradigm, a differential behavioral strategy of accelerated SVV reaction time was observed in the AIS group only when the PDs increased and (2) the decrease in P2 mean amplitudes with the increase in the PD levels might be direct evidence of the competition for central processing attentional resources under the dual-task postural control paradigm. PMID:28713252

Effect of vibration amplitude on vapor cavitation in journal bearings

NASA Astrophysics Data System (ADS)

Brewe, D. E.; Jacobson, B. O.

Computational movies were used to analyze the formation and collapse of vapor cavitation bubbles in a submerged journal bearing. The effect of vibration amplitude on vapor cavitation was studied for a journal undergoing circular whirl. The boundary conditions were implemented using Elrod's algorithm, which conserves mass flow through the cavitation bubble as well as through the oil-film region of the bearing. The vibration amplitudes for the different cases studied resulted in maximum eccentricity ratios ranging from 0.4 to 0.9. The minimum eccentricity ratio reached in each case was 0.1. For the least vibration amplitude studied in which the eccentricity ratio varied between 0.1 and 0.4, no vapor cavitation occurred. The largest vibration amplitude (i.e., eccentricity ratios of 0.1 to 0.9) resulted in vapor cavitation present 76 percent of one complete orbit.

Effect of vibration amplitude on vapor cavitation in journal bearings

NASA Technical Reports Server (NTRS)

Brewe, D. E.; Jacobson, B. O.

1986-01-01

Computational movies were used to analyze the formation and collapse of vapor cavitation bubbles in a submerged journal bearing. The effect of vibration amplitude on vapor cavitation was studied for a journal undergoing circular whirl. The boundary conditions were implemented using Elrod's algorithm, which conserves mass flow through the cavitation bubble as well as through the oil-film region of the bearing. The vibration amplitudes for the different cases studied resulted in maximum eccentricity ratios ranging from 0.4 to 0.9. The minimum eccentricity ratio reached in each case was 0.1. For the least vibration amplitude studied in which the eccentricity ratio varied between 0.1 and 0.4, no vapor cavitation occurred. The largest vibration amplitude (i.e., eccentricity ratios of 0.1 to 0.9) resulted in vapor cavitation present 76 percent of one complete orbit.

Neural Signatures of Rational and Heuristic Choice Strategies: A Single Trial ERP Analysis.

PubMed

Wichary, Szymon; Magnuski, Mikołaj; Oleksy, Tomasz; Brzezicka, Aneta

2017-01-01

In multi-attribute choice, people use heuristics to simplify decision problems. We studied the use of heuristic and rational strategies and their electrophysiological correlates. Since previous work linked the P3 ERP component to attention and decision making, we were interested whether the amplitude of this component is associated with decision strategy use. To this end, we recorded EEG when participants performed a two-alternative choice task, where they could acquire decision cues in a sequential manner and use them to make choices. We classified participants' choices as consistent with a rational Weighted Additive rule (WADD) or a simple heuristic Take The Best (TTB). Participants differed in their preference for WADD and TTB. Using a permutation-based single trial approach, we analyzed EEG responses to consecutive decision cues and their relation to the individual strategy preference. The preference for WADD over TTB was associated with overall higher signal amplitudes to decision cues in the P3 time window. Moreover, the preference for WADD was associated with similar P3 amplitudes to consecutive cues, whereas the preference for TTB was associated with substantial decreases in P3 amplitudes to consecutive cues. We also found that the preference for TTB was associated with enhanced N1 component to cues that discriminated decision alternatives, suggesting very early attention allocation to such cues by TTB users. Our results suggest that preference for either WADD or TTB has an early neural signature reflecting differences in attentional weighting of decision cues. In light of recent findings and hypotheses regarding P3, we interpret these results as indicating the involvement of catecholamine arousal systems in shaping predecisional information processing and strategy selection.

Neural Signatures of Rational and Heuristic Choice Strategies: A Single Trial ERP Analysis

PubMed Central

Wichary, Szymon; Magnuski, Mikołaj; Oleksy, Tomasz; Brzezicka, Aneta

2017-01-01

In multi-attribute choice, people use heuristics to simplify decision problems. We studied the use of heuristic and rational strategies and their electrophysiological correlates. Since previous work linked the P3 ERP component to attention and decision making, we were interested whether the amplitude of this component is associated with decision strategy use. To this end, we recorded EEG when participants performed a two-alternative choice task, where they could acquire decision cues in a sequential manner and use them to make choices. We classified participants’ choices as consistent with a rational Weighted Additive rule (WADD) or a simple heuristic Take The Best (TTB). Participants differed in their preference for WADD and TTB. Using a permutation-based single trial approach, we analyzed EEG responses to consecutive decision cues and their relation to the individual strategy preference. The preference for WADD over TTB was associated with overall higher signal amplitudes to decision cues in the P3 time window. Moreover, the preference for WADD was associated with similar P3 amplitudes to consecutive cues, whereas the preference for TTB was associated with substantial decreases in P3 amplitudes to consecutive cues. We also found that the preference for TTB was associated with enhanced N1 component to cues that discriminated decision alternatives, suggesting very early attention allocation to such cues by TTB users. Our results suggest that preference for either WADD or TTB has an early neural signature reflecting differences in attentional weighting of decision cues. In light of recent findings and hypotheses regarding P3, we interpret these results as indicating the involvement of catecholamine arousal systems in shaping predecisional information processing and strategy selection. PMID:28867996

Highly Doped Polycrystalline Silicon Microelectrodes Reduce Noise in Neuronal Recordings In Vivo

PubMed Central

Saha, Rajarshi; Jackson, Nathan; Patel, Chetan; Muthuswamy, Jit

2013-01-01

The aims of this study are to 1) experimentally validate for the first time the nonlinear current-potential characteristics of bulk doped polycrystalline silicon in the small amplitude voltage regimes (0–200 μV) and 2) test if noise amplitudes (0–15 μV) from single neuronal electrical recordings get selectively attenuated in doped polycrystalline silicon microelectrodes due to the above property. In highly doped polycrystalline silicon, bulk resistances of several hundred kilo-ohms were experimentally measured for voltages typical of noise amplitudes and 9–10 kΩ for voltages typical of neural signal amplitudes (>150–200 μV). Acute multiunit measurements and noise measurements were made in n = 6 and n = 8 anesthetized adult rats, respectively, using polycrystalline silicon and tungsten microelectrodes. There was no significant difference in the peak-to-peak amplitudes of action potentials recorded from either microelectrode (p > 0.10). However, noise power in the recordings from tungsten microelectrodes (26.36 ± 10.13 pW) was significantly higher (p < 0.001) than the corresponding value in polycrystalline silicon microelectrodes (7.49 ± 2.66 pW). We conclude that polycrystalline silicon microelectrodes result in selective attenuation of noise power in electrical recordings compared to tungsten microelectrodes. This reduction in noise compared to tungsten microelectrodes is likely due to the exponentially higher bulk resistances offered by highly doped bulk polycrystalline silicon in the range of voltages corresponding to noise in multiunit measurements. PMID:20667815

The Metabolic Costs of Sound Production in Odontocete Cetaceans

DTIC Science & Technology

2013-09-30

Veirs, V., Emmons, C., Veirs, S. 2009. Speaking up: Killer whales (Orcinus orca) increase their call amplitude in response to vessel noise. Journal...Acoustical Society of America 129: 2397. Parks, S.E, Johnson, M., Nowacek, D., Tyack P.L. 2010. Individual right whales call louder in increased

Effects of Amplitude Compression on Relative Auditory Distance Perception

DTIC Science & Technology

2013-10-01

FFT analyses are shown in Figure 4. The use of convolution of the stimuli with the binaural impulse responses recorded from KEMAR resulted in the...human sound localization (pp. 36-200). Cambridge, MA: The MIT Press. Carmichel, E. L., Harris, F. P., & Story, B. H. (2007). Effects of binaural

Effects of Aging on Arm Swing during Gait: The Role of Gait Speed and Dual Tasking.

PubMed

Mirelman, Anat; Bernad-Elazari, Hagar; Nobel, Tomer; Thaler, Avner; Peruzzi, Agnese; Plotnik, Meir; Giladi, Nir; Hausdorff, Jeffrey M

2015-01-01

Healthy walking is characterized by pronounced arm swing and axial rotation. Aging effects on gait speed, stride length and stride time variability have been previously reported, however, less is known about aging effects on arm swing and axial rotation and their relationship to age-associated gait changes during usual walking and during more challenging conditions like dual tasking. Sixty healthy adults between the ages of 30-77 were included in this study designed to address this gap. Lightweight body fixed sensors were placed on each wrist and lower back. Participants walked under 3 walking conditions each of 1 minute: 1) comfortable speed, 2) walking while serially subtracting 3's (Dual Task), 3) walking at fast speed. Aging effects on arm swing amplitude, range, symmetry, jerk and axial rotation amplitude and jerk were compared between decades of age (30-40; 41-50; 51-60; 61-77 years). As expected, older adults walked slower (p = 0.03) and with increased stride variability (p = 0.02). Arm swing amplitude decreased with age under all conditions (p = 0.04). In the oldest group, arm swing decreased during dual task and increased during the fast walking condition (p<0.0001). Similarly, arm swing asymmetry increased during the dual task in the older groups (p<0.004), but not in the younger groups (p = 0.67). Significant differences between groups and within conditions were observed in arm swing jerk (p<0.02), axial rotation amplitude (p<0.02) and axial jerk (p<0.001). Gait speed, arm swing amplitude of the dominant arm, arm swing asymmetry and axial rotation jerk were all independent predictors of age in a multivariate model. These findings suggest that the effects of gait speed and dual tasking on arm swing and axial rotation during walking are altered among healthy older adults. Follow-up work is needed to examine if these effects contribute to reduced stability in aging.

Effects of Aging on Arm Swing during Gait: The Role of Gait Speed and Dual Tasking

PubMed Central

Mirelman, Anat; Bernad-Elazari, Hagar; Nobel, Tomer; Thaler, Avner; Peruzzi, Agnese; Plotnik, Meir; Giladi, Nir; Hausdorff, Jeffrey M.

2015-01-01

Healthy walking is characterized by pronounced arm swing and axial rotation. Aging effects on gait speed, stride length and stride time variability have been previously reported, however, less is known about aging effects on arm swing and axial rotation and their relationship to age-associated gait changes during usual walking and during more challenging conditions like dual tasking. Sixty healthy adults between the ages of 30–77 were included in this study designed to address this gap. Lightweight body fixed sensors were placed on each wrist and lower back. Participants walked under 3 walking conditions each of 1 minute: 1) comfortable speed, 2) walking while serially subtracting 3’s (Dual Task), 3) walking at fast speed. Aging effects on arm swing amplitude, range, symmetry, jerk and axial rotation amplitude and jerk were compared between decades of age (30–40; 41–50; 51–60; 61–77 years). As expected, older adults walked slower (p = 0.03) and with increased stride variability (p = 0.02). Arm swing amplitude decreased with age under all conditions (p = 0.04). In the oldest group, arm swing decreased during dual task and increased during the fast walking condition (p<0.0001). Similarly, arm swing asymmetry increased during the dual task in the older groups (p<0.004), but not in the younger groups (p = 0.67). Significant differences between groups and within conditions were observed in arm swing jerk (p<0.02), axial rotation amplitude (p<0.02) and axial jerk (p<0.001). Gait speed, arm swing amplitude of the dominant arm, arm swing asymmetry and axial rotation jerk were all independent predictors of age in a multivariate model. These findings suggest that the effects of gait speed and dual tasking on arm swing and axial rotation during walking are altered among healthy older adults. Follow-up work is needed to examine if these effects contribute to reduced stability in aging. PMID:26305896

Study of inelastic decay amplitudes in /sup 51/Mn

DOE Office of Scientific and Technical Information (OSTI.GOV)

Whatley, K.M.

1982-01-01

Detailed angular distribution measurments on inelastically scattered protons and de-excitation ..gamma..-rays in the /sup 50/Cr(p,p') and /sup 50/Cr(p,p'..gamma..) reactions were performed for 107 resonances in /sup 51/Mn in the proton energy range 3.0-4.4 MeV. An overall resolution of 425 eV was obtained with the tandem Van de Graaff accelerator and the high resolution system at the Triangle Universities Nuclear Laboratory. Spin and parity assignments for the 107 resonances studied were as follows: 1/2/sup +/ (4); 1/2/sup -/ (6); 3/2/sup -/ (30); 3/2/sup +/ (20); 5/2/sup +/ (38); 5/2/sup -/ (7); 7/2/sup +/ (1); and 9/2/sup +/ (1). Mixing ratios formore » the inelastic decay amplitudes were uniquely determined for all resonances except those assigned J/sup ..pi../ = 1/2/sup +/, 1/2/sup -/, or 3/2/sup +/. For 1/2/sup +/ and 1/2/sup -/ resonances there is only one open decay channel. For 3/2/sup +/ resonances, insufficient information is obtained from this experiment to determine a unique solution for the mixing ratios. Statistical studies were performed on the set of 3/2/sup -/ resonances and on the set of 5/2/sup +/ resonances. Strong channel-channel correlations were observed in the distributions of the reduced widths and the reduced width amplitudes for 5/2/sup +/ resonances. The existence of such correlations is a violation of the extreme statistical model. The present results agree with the reduced width amplitude distribution of Krieger and Porter which includes channel-channel correlations.« less

Dynamic stability of passive dynamic walking on an irregular surface.

PubMed

Su, Jimmy Li-Shin; Dingwell, Jonathan B

2007-12-01

Falls that occur during walking are a significant health problem. One of the greatest impediments to solve this problem is that there is no single obviously "correct" way to quantify walking stability. While many people use variability as a proxy for stability, measures of variability do not quantify how the locomotor system responds to perturbations. The purpose of this study was to determine how changes in walking surface variability affect changes in both locomotor variability and stability. We modified an irreducibly simple model of walking to apply random perturbations that simulated walking over an irregular surface. Because the model's global basin of attraction remained fixed, increasing the amplitude of the applied perturbations directly increased the risk of falling in the model. We generated ten simulations of 300 consecutive strides of walking at each of six perturbation amplitudes ranging from zero (i.e., a smooth continuous surface) up to the maximum level the model could tolerate without falling over. Orbital stability defines how a system responds to small (i.e., "local") perturbations from one cycle to the next and was quantified by calculating the maximum Floquet multipliers for the model. Local stability defines how a system responds to similar perturbations in real time and was quantified by calculating short-term and long-term local exponential rates of divergence for the model. As perturbation amplitudes increased, no changes were seen in orbital stability (r(2)=2.43%; p=0.280) or long-term local instability (r(2)=1.0%; p=0.441). These measures essentially reflected the fact that the model never actually "fell" during any of our simulations. Conversely, the variability of the walker's kinematics increased exponentially (r(2)>or=99.6%; p<0.001) and short-term local instability increased linearly (r(2)=88.1%; p<0.001). These measures thus predicted the increased risk of falling exhibited by the model. For all simulated conditions, the walker remained orbitally stable, while exhibiting substantial local instability. This was because very small initial perturbations diverged away from the limit cycle, while larger initial perturbations converged toward the limit cycle. These results provide insight into how these different proposed measures of walking stability are related to each other and to risk of falling.

Acoustical Scattering from an Elastic Sphere in Water: Surface Wave Glory, Resonances, and the Sommerfeld-Watson Transformation for Amplitudes

DTIC Science & Technology

1985-08-01

travels around the sphere (indicated by the dotted rays in Fig. 3). At the point• 2 energy is reradiated into the liquid in the direction of the receiver P...loaded elastic cylinder. 3 58 Using the coordinate system shown in Fig. 1 and au~uing a unit amplitude plane wave traveling in the +t direction the...reflection measured relative to a wave traveling in liquid alon1- the path (r ’ ’., e = 7) (r 0) -0 (r = 9, a ir--y). We have previously obtained results

Regional Seismic Methods of Identifying Explosions

NASA Astrophysics Data System (ADS)

Walter, W. R.; Ford, S. R.; Pasyanos, M.; Pyle, M. L.; Hauk, T. F.

2013-12-01

A lesson from the 2006, 2009 and 2013 DPRK declared nuclear explosion Ms:mb observations is that our historic collection of data may not be representative of future nuclear test signatures (e.g. Selby et al., 2012). To have confidence in identifying future explosions amongst the background of other seismic signals, we need to put our empirical methods on a firmer physical footing. Here we review the two of the main identification methods: 1) P/S ratios and 2) Moment Tensor techniques, which can be applied at the regional distance (200-1600 km) to very small events, improving nuclear explosion monitoring and confidence in verifying compliance with the Comprehensive Nuclear-Test-Ban Treaty (CTBT). Amplitude ratios of seismic P-to-S waves at sufficiently high frequencies (~>2 Hz) can identify explosions among a background of natural earthquakes (e.g. Walter et al., 1995). However the physical basis for the generation of explosion S-waves, and therefore the predictability of this P/S technique as a function of event properties such as size, depth, geology and path, remains incompletely understood. Calculated intermediate period (10-100s) waveforms from regional 1-D models can match data and provide moment tensor results that separate explosions from earthquakes and cavity collapses (e.g. Ford et al. 2009). However it has long been observed that some nuclear tests produce large Love waves and reversed Rayleigh waves that complicate moment tensor modeling. Again the physical basis for the generation of these effects from explosions remains incompletely understood. We are re-examining regional seismic data from a variety of nuclear test sites including the DPRK and the former Nevada Test Site (now the Nevada National Security Site (NNSS)). Newer relative amplitude techniques can be employed to better quantify differences between explosions and used to understand those differences in term of depth, media and other properties. We are also making use of the Source Physics Experiments (SPE) at NNSS. The SPE chemical explosions are explicitly designed to improve our understanding of emplacement and source material effects on the generation of shear and surface waves (e.g. Snelson et al., 2013). Our goal is to improve our explosion models and our ability to understand and predict where P/S and moment tensor methods of identifying explosions work, and any circumstances where they may not. This work performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.

Analysis of the tremor in juvenile myoclonic epilepsy.

PubMed

Aydin-Özemir, Zeynep; Matur, Zeliha; Baykan, Betul; Bilgic, Başar; Tekturk, Pınar; Bebek, Nerses; Gurses, Candan; Hanagasi, Hasmet; Oge, Ali Emre

2016-12-01

We aimed to investigate juvenile myoclonic epilepsy (JME) patients complaining of tremor unrelated to valproate (VPA) treatment and evaluate if there were differences between JME patients with and without tremor and essential tremor (ET) patients to exclude comorbidity. Fifteen JME cases with the complaint of tremor, 14 JME patients without tremor, 14 patients with ET and 14 healthy subjects (HS) were included. Regularity, frequency and amplitude of the tremor and superimposed myoclonia were assessed by accelerometric analysis. Cortical SEPs evoked by the stimulation of the median nerve were recorded bilaterally. Clinical and neurophysiologic features were statistically compared between the groups. Amplitude of postural tremor of the left hand was significantly increased in the ET group compared to JME patients with tremor, but there were no differences regarding to frequency. Strikingly, there were superimposed irregular, low-amplitude inconstant myoclonic jerks located to distal part of the fingers in JME group with tremor. Initial frequency of myoclonic seizures was also significantly higher in this group compared to JME patients without tremor but this difference disappeared after treatment. The group of JME with tremor had the highest N20-P25 and P25-N35 amplitudes, followed by JME without tremor, ET and HS, respectively. Tremulous hand movements in JME resembled ET, but their amplitude was lower and characterized with accompanying irregular myoclonic jerks. The presence of tremor in JME patients should be taken into consideration to create more homogeneous groups in genetic and pathophysiological studies of JME. Copyright © 2016 Elsevier B.V. All rights reserved.

Background noise can enhance cortical auditory evoked potentials under certain conditions

PubMed Central

Papesh, Melissa A.; Billings, Curtis J.; Baltzell, Lucas S.

2017-01-01

Objective To use cortical auditory evoked potentials (CAEPs) to understand neural encoding in background noise and the conditions under which noise enhances CAEP responses. Methods CAEPs from 16 normal-hearing listeners were recorded using the speech syllable/ba/presented in quiet and speech-shaped noise at signal-to-noise ratios of 10 and 30 dB. The syllable was presented binaurally and monaurally at two presentation rates. Results The amplitudes of N1 and N2 peaks were often significantly enhanced in the presence of low-level background noise relative to quiet conditions, while P1 and P2 amplitudes were consistently reduced in noise. P1 and P2 amplitudes were significantly larger during binaural compared to monaural presentations, while N1 and N2 peaks were similar between binaural and monaural conditions. Conclusions Methodological choices impact CAEP peaks in very different ways. Negative peaks can be enhanced by background noise in certain conditions, while positive peaks are generally enhanced by binaural presentations. Significance Methodological choices significantly impact CAEPs acquired in quiet and in noise. If CAEPs are to be used as a tool to explore signal encoding in noise, scientists must be cognizant of how differences in acquisition and processing protocols selectively shape CAEP responses. PMID:25453611

[The importance of vestibular evoked myogenic potentials for the assessment of the otolith function in the patients presenting with benign paroxysmal positional vertigo].

PubMed

Kunel'skaya, N L; Baybakova, E V; Guseva, A L; Chugunova, M A; Manaenkova, E A

The objective of the present study was to evaluate the otolith function in the patients presenting with idiopathic benign paroxysmal positional vertigo (pBPPV) attributable to the occlusion of the posterior semicircular canal (PSCC) of the inner ear with the use of vestibular evoked myogenic potentials (VEMP). Cervical (cVEMP) and ocular VEMP (oVEMP) were measured in 34 patients with idiopathic pBPPV before and 7 days after the treatment by means of reposition maneuvers. The results of the repeated Dix-Hallpike test performed 7 days after the repositioning maneuver were negative in 27 patients and positive in 7 patients. There was no statistically significant difference in the amplitude of cervical VEMP between the healthy and affected ears either before or after the repositioning treatment. The measurement of oVEMP revealed a reduction of the response amplitude on the affected side. The average values of the plnl on the healthy side were 12.84±1.09 and those on the affected side 4.62±0.69 (p<0,05). The successful repositioning treatment resulted in a significant increase of the oVEMP amplitude on the affected side (p<0,05). In the patients presenting with the persistent symptoms of pBPPV, the repositioning maneuvers did not cause an appreciable increase in the amplitude of oVEMP on the affected side (p<0.05). The results of the present study give evidence that pBPPV of the posterior semicircular canal is associated with the impairment of the function of the receptor structures of the utriculus and the preserved function of the succulus as suggested by the reduction of the oVEMP amplitude and clinically significant asymmetry of ocular VEMP on the affected side with intact cervical VEMP on both sides. The successful treatment of pBPPV of PSCC with the use of the liberatory maneuver results in the increase of the oVEMP amplitude on the affected side increases while the response asymmetry between both sides significantly decreases which indicates the repair of the utriculus otolith function.

Fatigue testing of a NiTi rotary instrument. Part 2: Fractographic analysis.

PubMed

Cheung, G S P; Darvell, B W

2007-08-01

To examine the topographic features of the fracture surface of a NiTi instrument after fatigue failure, and to correlate the measurements of some features with the cyclic load. A total of 212 ProFile rotary instruments were subjected to a rotational-bending test at various curvatures until broken. The fracture surface of all fragments was examined by SEM to identify the crack origins. The crack radius, i.e. extent of the fatigue-crack growth towards the centroid of the cross-section, was also measured, and correlated with the strain amplitude for each instrument. All fracture surfaces revealed the presence of one or more crack origins, a region occupied by microscopic striations, and an area with microscopic dimples. The number of specimens showing multiple crack origins was significantly greater in the group fatigued under water than in air (P < 0.05). A linear relationship between the reciprocal of the square root of the crack radius and the strain amplitude was discernible (P < 0.001), the slopes of which were not significantly different for instruments fatigued in air and water. The fractographic appearance of NiTi engine-files that had failed because of fatigue is typical of that for other metals. The fatigue behaviour of NiTi instruments is adversely affected by water, not only for the low-cycle fatigue life, but also the number of crack origins. There appears to be a critical extent of crack propagation for various strain amplitudes leading to final rupture (akin to the Griffith's criterion for brittle materials).

Influence of spatial frequency and emotion expression on face processing in patients with panic disorder.

PubMed

Shim, Miseon; Kim, Do-Won; Yoon, Sunkyung; Park, Gewnhi; Im, Chang-Hwan; Lee, Seung-Hwan

2016-06-01

Deficits in facial emotion processing is a major characteristic of patients with panic disorder. It is known that visual stimuli with different spatial frequencies take distinct neural pathways. This study investigated facial emotion processing involving stimuli presented at broad, high, and low spatial frequencies in patients with panic disorder. Eighteen patients with panic disorder and 19 healthy controls were recruited. Seven event-related potential (ERP) components: (P100, N170, early posterior negativity (EPN); vertex positive potential (VPP), N250, P300; and late positive potential (LPP)) were evaluated while the participants looked at fearful and neutral facial stimuli presented at three spatial frequencies. When a fearful face was presented, panic disorder patients showed a significantly increased P100 amplitude in response to low spatial frequency compared to high spatial frequency; whereas healthy controls demonstrated significant broad spatial frequency dependent processing in P100 amplitude. Vertex positive potential amplitude was significantly increased in high and broad spatial frequency, compared to low spatial frequency in panic disorder. Early posterior negativity amplitude was significantly different between HSF and BSF, and between LSF and BSF processing in both groups, regardless of facial expression. The possibly confounding effects of medication could not be controlled. During early visual processing, patients with panic disorder prefer global to detailed information. However, in later processing, panic disorder patients overuse detailed information for the perception of facial expressions. These findings suggest that unique spatial frequency-dependent facial processing could shed light on the neural pathology associated with panic disorder. Copyright © 2016 Elsevier B.V. All rights reserved.

{lambda}{sub b}{yields}p, {lambda} transition form factors from QCD light-cone sum rules

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang Yuming; Lue Caidian; Shen Yuelong

2009-10-01

Light-cone sum rules for the {lambda}{sub b}{yields}p, {lambda} transition form factors are derived from the correlation functions expanded by the twist of the distribution amplitudes of the {lambda}{sub b} baryon. In terms of the {lambda}{sub b} three-quark distribution amplitude models constrained by the QCD theory, we calculate the form factors at small momentum transfers and compare the results with those estimated in the conventional light-cone sum rules (LCSR) and perturbative QCD approaches. Our results indicate that the two different versions of sum rules can lead to the consistent numbers of form factors responsible for {lambda}{sub b}{yields}p transition. The {lambda}{sub b}{yields}{lambda}more » transition form factors from LCSR with the asymptotic {lambda} baryon distribution amplitudes are found to be almost 1 order larger than those obtained in the {lambda}{sub b}-baryon LCSR, implying that the preasymptotic corrections to the baryonic distribution amplitudes are of great importance. Moreover, the SU(3) symmetry breaking effects between the form factors f{sub 1}{sup {lambda}{sub b}}{sup {yields}}{sup p} and f{sub 1}{sup {lambda}{sub b}}{sup {yields}}{sup {lambda}} are computed as 28{sub -8}{sup +14}% in the framework of {lambda}{sub b}-baryon LCSR.« less

Elastic scattering, polarization and absorption of relativistic antiprotons on nuclei

NASA Astrophysics Data System (ADS)

Larionov, A. B.; Lenske, H.

2017-01-01

We perform Glauber model calculations of the antiproton-nucleus elastic and quasielastic scattering and absorption in the beam momentum range ∼ 0.5 ÷ 10 GeV / c. A good agreement of our calculations with available LEAR data and with earlier Glauber model studies of the p bar A elastic scattering allows us to make predictions at the beam momenta of ∼10 GeV/c, i.e. at the regime of the PANDA experiment at FAIR. The comparison with the proton-nucleus elastic scattering cross sections shows that the diffractive minima are much deeper in the p bar A case due to smaller absolute value of the ratio of the real-to-imaginary part of the elementary elastic amplitude. Significant polarization signal for p bar A elastic scattering at 10 GeV/c is expected. We have also revealed a strong dependence of the p bar A absorption cross section on the slope parameter of the transverse momentum dependence of the elementary p bar N amplitude. The p bar A optical potential is discussed.

Neural and Muscular Contributions to the Age-Related Reductions in Rapid Strength.

PubMed

Gerstner, Gena R; Thompson, Brennan J; Rosenberg, Joseph G; Sobolewski, Eric J; Scharville, Michael J; Ryan, Eric D

2017-07-01

The purposes of this study were to investigate the age-related differences in absolute and normalized plantarflexion rate of torque development (RTD) at early (0-50 ms) and late (100-200 ms) time intervals and to examine specific neural and muscular mechanisms contributing to these differences. Thirty-two young (20.0 ± 2.1 yr) and 20 older (69.5 ± 3.3 yr) recreationally active men performed rapid plantarflexion isometric muscle actions to examine absolute and normalized RTD and muscle activation using EMG at early and late time intervals. Ultrasonography was used to examine medial gastrocnemius muscle size, echo intensity (EI), and muscle architecture (fascicle length [FL] and pennation angle [PA]). The older men were weaker (23.9%, P < 0.001) and had lower later absolute and normalized RTD (P = 0.001-0.034) variables when compared with the young men. The older men also had higher EI (P < 0.001), smaller PA (P = 0.004), and lower later EMG amplitude values (P = 0.009-0.046). However, there were no differences in early RTD and EMG amplitude values, muscle size, or FL between groups (P = 0.097-0.914). Lower late RTD values were related to higher EI, smaller PA, and lower EMG amplitude values (r = -0.28-0.59, P = 0.001-0.044); however, late RTD values were no longer related to PA after normalizing to peak torque. Age-related alterations in muscle quality (EI), architecture, and muscle activation may influence rapid torque production at late time intervals (≥100 ms) from contraction onset. These findings highlight specific neuromuscular factors that influence the age-related reductions in RTD, which has been shown to significantly influence function and performance in older adults.

A Solar System Survey of Forced Librations in Longitude

NASA Technical Reports Server (NTRS)

Cornstock, Robert L.; Bills, Bruce G.

2003-01-01

Forced librations are periodic rotational rate variations due to gravitational interactions with an orbital partner. We have developed an analytic theory capable of calculating expected amplitudes of forced librations for nonresonant rotators as well as for bodies existing in a spin-orbit resonance. The theory has been applied to 34 solar system bodies, including terrestrial planets, planetary satellites, and the asteroid Eros. Parameters governing libration amplitude are the body s orbital eccentricity, moment difference, and the ratio of its spin rate to its orbital rate. In each case the largest libration amplitude is associated with the forcing frequency 2 (p - 1) n, where n is the orbital mean motion and p is the spin/orbit rate ratio. This dominant frequency is simply semidiurnal as seen from the position of the torquing body. The maximum libration angular amplitude is 1.3 x 10(exp -2) radians for Thebe, and the maximum mean equatorial displacement is 1.4 km for Mimas.

Usefulness of Intraoperative Monitoring of Visual Evoked Potentials in Transsphenoidal Surgery

PubMed Central

KAMIO, Yoshinobu; SAKAI, Naoto; SAMESHIMA, Tetsuro; TAKAHASHI, Goro; KOIZUMI, Shinichiro; SUGIYAMA, Kenji; NAMBA, Hiroki

2014-01-01

Postoperative visual outcome is a major concern in transsphenoidal surgery (TSS). Intraoperative visual evoked potential (VEP) monitoring has been reported to have little usefulness in predicting postoperative visual outcome. To re-evaluate its usefulness, we adapted a high-power light-stimulating device with electroretinography (ERG) to ascertain retinal light stimulation. Intraoperative VEP monitoring was conducted in TSSs in 33 consecutive patients with sellar and parasellar tumors under total venous anesthesia. The detectability rates of N75, P100, and N135 were 94.0%, 85.0%, and 79.0%, respectively. The mean latencies and amplitudes of N75, P100, and N135 were 76.8 ± 6.4 msec and 4.6 ± 1.8 μV, 98.0 ± 8.6 msec and 5.0 ± 3.4 μV, and 122.1 ± 16.3 msec and 5.7 ± 2.8 μV, respectively. The amplitude was defined as the voltage difference from N75 to P100 or P100 to N135. The criterion for amplitude changes was defined as a > 50% increase or 50% decrease in amplitude compared to the control level. The surgeon was immediately alerted when the VEP changed beyond these thresholds, and the surgical manipulations were stopped until the VEP recovered. Among the 28 cases with evaluable VEP recordings, the VEP amplitudes were stable in 23 cases and transiently decreased in 4 cases. In these 4 cases, no postoperative vision deterioration was observed. One patient, whose VEP amplitude decreased without subsequent recovery, developed vision deterioration. Intraoperative VEP monitoring with ERG to ascertain retinal light stimulation by the new stimulus device was reliable and feasible in preserving visual function in patients undergoing TSS. PMID:25070017

Quantitative Study for the Surface Dehydration of Vocal Folds Based on High-Speed Imaging.

PubMed

Li, Lin; Zhang, Yu; Maytag, Allison L; Jiang, Jack J

2015-07-01

From the perspective of the glottal area and mucosal wave, quantitatively estimate the differences of vocal fold on laryngeal activity during phonation at three different dehydration levels. Controlled three sets of tests. A dehydration experiment for 10 excised canine larynges was conducted at 16 cm H2O. According to the dehydration cycle time (H), dehydration levels were divided into three degrees (0% H, 50% H, 75% H). The glottal area and mucosal wave under three dehydration levels were extracted from high-speed images and digital videokymography (DKG) image sequences. Direct and non-direct amplitude components were derived from glottal areas. The amplitude and frequency of mucosal wave were calculated from DKG image sequences. These parameters in condition of three dehydration levels were compared for statistical analysis. The results showed a significant difference in direct (P = 0.001; P = 0.005) and non-direct (P = 0.005; P = 0.016) components of glottal areas between every two different dehydration levels. Considering the right-upper, right-lower, left-upper, and left-lower of vocal fold, the amplitudes of mucosal waves consistently decreased with increasing of dehydration levels. But, there was no significant difference in frequency. Surface dehydration could give rise to complex variation of vocal fold on tissues and vibratory mechanism, which should need analyzing from multiple perspectives. The results suggested that the combination of glottal area and mucosal wave could be better to research the change of vocal fold at different dehydrations. It would become a better crucial research tool for the clinical treatment of dehydration-induced laryngeal pathologies. Copyright © 2015 The Voice Foundation. Published by Elsevier Inc. All rights reserved.

Trunk Muscle Activity during Drop Jump Performance in Adolescent Athletes with Back Pain.

PubMed

Mueller, Steffen; Stoll, Josefine; Mueller, Juliane; Cassel, Michael; Mayer, Frank

2017-01-01

In the context of back pain, great emphasis has been placed on the importance of trunk stability, especially in situations requiring compensation of repetitive, intense loading induced during high-performance activities, e.g., jumping or landing. This study aims to evaluate trunk muscle activity during drop jump in adolescent athletes with back pain (BP) compared to athletes without back pain (NBP). Eleven adolescent athletes suffering back pain (BP: m/f: n = 4/7; 15.9 ± 1.3 y; 176 ± 11 cm; 68 ± 11 kg; 12.4 ± 10.5 h/we training) and 11 matched athletes without back pain (NBP: m/f: n = 4/7; 15.5 ± 1.3 y; 174 ± 7 cm; 67 ± 8 kg; 14.9 ± 9.5 h/we training) were evaluated. Subjects conducted 3 drop jumps onto a force plate (ground reaction force). Bilateral 12-lead SEMG (surface Electromyography) was applied to assess trunk muscle activity. Ground contact time [ms], maximum vertical jump force [N], jump time [ms] and the jump performance index [m/s] were calculated for drop jumps. SEMG amplitudes (RMS: root mean square [%]) for all 12 single muscles were normalized to MIVC (maximum isometric voluntary contraction) and analyzed in 4 time windows (100 ms pre- and 200 ms post-initial ground contact, 100 ms pre- and 200 ms post-landing) as outcome variables. In addition, muscles were grouped and analyzed in ventral and dorsal muscles, as well as straight and transverse trunk muscles. Drop jump ground reaction force variables did not differ between NBP and BP ( p > 0.05). Mm obliquus externus and internus abdominis presented higher SEMG amplitudes (1.3-1.9-fold) for BP ( p < 0.05). Mm rectus abdominis, erector spinae thoracic/lumbar and latissimus dorsi did not differ ( p > 0.05). The muscle group analysis over the whole jumping cycle showed statistically significantly higher SEMG amplitudes for BP in the ventral ( p = 0.031) and transverse muscles ( p = 0.020) compared to NBP. Higher activity of transverse, but not straight, trunk muscles might indicate a specific compensation strategy to support trunk stability in athletes with back pain during drop jumps. Therefore, exercises favoring the transverse trunk muscles could be recommended for back pain treatment.

[Evoked potentials in the human visual cortex when observing whole figures and their elements].

PubMed

Slavutskaia, A V; Mikhaĭlova, E S

2010-01-01

Evoked potentials changes were analyzed in 32 subjects in a task of observing whole and disintegrated images. In the occipital and parietal regions, reactions to a disintegrated image appeared early (within the period of P1 development), and their characteristics were determined by the magnitude of the response to the whole image. In the occipital cortex, a low-amplitude P1 (the 1st group of subjects) increased in response to image disintegration, whereas in cases of a high P1 amplitude (the 2nd group), the tendency to its reduction was observed. In the parietal regions, the effects were distinct only in the 1st group of subjects and different in the right and left hemispheres: in the left hemisphere, the P1 amplitude increased when simpler elements appeared in the image, in the right hemisphere, a change in the spatial disposition of details was more significant. In the inferior temporal cortex, the amplitude of the later wave N1 decreased in response to disintegration, the effect being significant only in the 2nd group of subjects. The appearance of simpler elements in the image resulted in a P3 wave increase in both groups. The results point to topographic and temporal specificity of the reactions of the visual cortex to image disintegration and suggest the existence of various strategies of the visual image analysis at the early stages.

Do resting brain dynamics predict oddball evoked-potential?

PubMed Central

2011-01-01

Background The oddball paradigm is widely applied to the investigation of cognitive function in neuroscience and in neuropsychiatry. Whether cortical oscillation in the resting state can predict the elicited oddball event-related potential (ERP) is still not clear. This study explored the relationship between resting electroencephalography (EEG) and oddball ERPs. The regional powers of 18 electrodes across delta, theta, alpha and beta frequencies were correlated with the amplitude and latency of N1, P2, N2 and P3 components of oddball ERPs. A multivariate analysis based on partial least squares (PLS) was applied to further examine the spatial pattern revealed by multiple correlations. Results Higher synchronization in the resting state, especially at the alpha spectrum, is associated with higher neural responsiveness and faster neural propagation, as indicated by the higher amplitude change of N1/N2 and shorter latency of P2. None of the resting quantitative EEG indices predict P3 latency and amplitude. The PLS analysis confirms that the resting cortical dynamics which explains N1/N2 amplitude and P2 latency does not show regional specificity, indicating a global property of the brain. Conclusions This study differs from previous approaches by relating dynamics in the resting state to neural responsiveness in the activation state. Our analyses suggest that the neural characteristics carried by resting brain dynamics modulate the earlier/automatic stage of target detection. PMID:22114868

Mild Airflow Limitation during N2 Sleep Increases K-complex Frequency and Slows Electroencephalographic Activity

PubMed Central

Nguyen, Chinh D.; Wellman, Andrew; Jordan, Amy S.; Eckert, Danny J.

2016-01-01

Study Objectives: To determine the effects of mild airflow limitation on K-complex frequency and morphology and electroencephalogram (EEG) spectral power. Methods: Transient reductions in continuous positive airway pressure (CPAP) during stable N2 sleep were performed to induce mild airflow limitation in 20 patients with obstructive sleep apnea (OSA) and 10 healthy controls aged 44 ± 13 y. EEG at C3 and airflow were measured in 1-min windows to quantify K-complex properties and EEG spectral power immediately before and during transient reductions in CPAP. The frequency and morphology (amplitude and latency of P200, N550 and N900 components) of K-complexes and EEG spectral power were compared between conditions. Results: During mild airflow limitation (18% reduction in peak inspiratory airflow from baseline, 0.38 ± 0.11 versus 0.31 ± 0.1 L/sec) insufficient to cause American Academy of Sleep Medicine-defined cortical arousal, K-complex frequency (9.5 ± 4.5 versus 13.7 ± 6.4 per min, P < 0.01), N550 amplitude (25 ± 3 versus 27 ± 3 μV, P < 0.01) and EEG spectral power (delta: 147 ± 48 versus 230 ± 99 μV2, P < 0.01 and theta bands: 31 ± 14 versus 34 ± 13 μV2, P < 0.01) significantly increased whereas beta band power decreased (14 ± 5 versus 11 ± 4 μV2, P < 0.01) compared to the preceding non flow-limited period on CPAP. K-complex frequency, morphology, and timing did not differ between patients and controls. Conclusion: Mild airflow limitation increases K-complex frequency, N550 amplitude, and spectral power of delta and theta bands. In addition to providing mechanistic insight into the role of mild airflow limitation on K-complex characteristics and EEG activity, these findings may have important implications for respiratory conditions in which airflow limitation during sleep is common (e.g., snoring and OSA). Citation: Nguyen CD, Wellman A, Jordan AS, Eckert DJ. Mild airflow limitation during N2 sleep increases k-complex frequency and slows electroencephalographic activity. SLEEP 2016;39(3):541–550. PMID:26612389

Projectors, associators, visual imagery, and the time course of visual processing in grapheme-color synesthesia.

PubMed

Amsel, Ben D; Kutas, Marta; Coulson, Seana

2017-10-01

In grapheme-color synesthesia, seeing particular letters or numbers evokes the experience of specific colors. We investigate the brain's real-time processing of words in this population by recording event-related brain potentials (ERPs) from 15 grapheme-color synesthetes and 15 controls as they judged the validity of word pairs ('yellow banana' vs. 'blue banana') presented under high and low visual contrast. Low contrast words elicited delayed P1/N170 visual ERP components in both groups, relative to high contrast. When color concepts were conveyed to synesthetes by individually tailored achromatic grapheme strings ('55555 banana'), visual contrast effects were like those in color words: P1/N170 components were delayed but unchanged in amplitude. When controls saw equivalent colored grapheme strings, visual contrast modulated P1/N170 amplitude but not latency. Color induction in synesthetes thus differs from color perception in controls. Independent from experimental effects, all orthographic stimuli elicited larger N170 and P2 in synesthetes than controls. While P2 (150-250ms) enhancement was similar in all synesthetes, N170 (130-210ms) amplitude varied with individual differences in synesthesia and visual imagery. Results suggest immediate cross-activation in visual areas processing color and shape is most pronounced in so-called projector synesthetes whose concurrent colors are experienced as originating in external space.

A P300 event related potential technique for assessment of sexually oriented interest.

PubMed

Vardi, Yoram; Volos, Michal; Sprecher, Elliot; Granovsky, Yelena; Gruenwald, Ilan; Yarnitsky, David

2006-12-01

Despite all of the modern, sophisticated tests that exist for diagnosing and assessing male and female sexual disorders, to our knowledge there is no objective psychophysiological test to evaluate sexual arousal and interest. We provide preliminary data showing a decrease in auditory P300 wave amplitude during exposure to sexually explicit video clips and a significant correlation between the auditory P300 amplitude decrease and self-reported scores of sexual arousal and interest in the clips. A total of 30 healthy subjects were exposed to several blocks of auditory stimuli administered using an oddball paradigm. Baseline auditory P300 amplitudes were obtained and auditory stimuli were then delivered while viewing visual clips with 3 types of content, including sport, scenery and sex. Auditory P300 amplitude significantly decreased during viewing clips of all contents. Viewing sexual content clips caused a maximal decrease in P300 amplitude (p <0.0001). In addition, a high correlation was found between the amplitude decrease and scores on the sexual arousal questionnaire regarding the viewed clips (r = 0.61, p <0.001). In addition, the P300 amplitude decrease was significantly related to the sexual interest score (r = 0.37, p = 0.042) but not to interest in clips of nonsexual content. The change in auditory P300 amplitude during exposure to visual stimuli with sexual context seems to be an objective measure of subject sexual interest. This method might be applied to assess therapeutic intervention and as a diagnostic tool for assessing disorders of impaired libido or psychogenic sexual dysfunction.

Surface electromyographic analysis of differential effects in kettlebell carries for the serratus anterior muscles.

PubMed

Caravan, Alex; Scheffey, John O; Briend, Sam J; Boddy, Kyle J

2018-01-01

The purpose of this study was to examine differences in the Electromyography (EMG) amplitude of the serratus anterior between 45° kettlebell carries and 90° kettlebell carries. Thirty-three men aged roughly between 19 and 23 and who were either college or professional baseball pitchers were chosen and randomly assigned to either perform the 45° kettlebell carry followed by the 90° kettlebell carry ( n = 17) or the 90° kettlebell carry followed by the 45° kettlebell carry ( n = 16). Each pitcher was instructed in the proper usage of the exercise and assigned a short break between the two carries. Changes in EMG amplitude were examined after proper band-pass filtering, normalization, and moving average-smoothing of the raw EMG signal. Differences of the EMG amplitude mean frequencies were examined between each subject's individual carries and the clumped groups of all 45° and 90° carries. Among each individual comparison, eight pitchers had "large" Effect Size differences between the EMG amplitudes of their two carries, with seven of them signaling the 45° carry as the larger value. In addition, when examining the grouped mean differences of the EMG amplitudes, we found the 45° carries to be significantly higher ( p -value of 0.018).

Surface electromyographic analysis of differential effects in kettlebell carries for the serratus anterior muscles

PubMed Central

2018-01-01

The purpose of this study was to examine differences in the Electromyography (EMG) amplitude of the serratus anterior between 45° kettlebell carries and 90° kettlebell carries. Thirty-three men aged roughly between 19 and 23 and who were either college or professional baseball pitchers were chosen and randomly assigned to either perform the 45° kettlebell carry followed by the 90° kettlebell carry (n = 17) or the 90° kettlebell carry followed by the 45° kettlebell carry (n = 16). Each pitcher was instructed in the proper usage of the exercise and assigned a short break between the two carries. Changes in EMG amplitude were examined after proper band-pass filtering, normalization, and moving average-smoothing of the raw EMG signal. Differences of the EMG amplitude mean frequencies were examined between each subject’s individual carries and the clumped groups of all 45° and 90° carries. Among each individual comparison, eight pitchers had “large” Effect Size differences between the EMG amplitudes of their two carries, with seven of them signaling the 45° carry as the larger value. In addition, when examining the grouped mean differences of the EMG amplitudes, we found the 45° carries to be significantly higher (p-value of 0.018). PMID:29910993

Event-related potentials during visual selective attention in children of alcoholics.

PubMed

van der Stelt, O; Gunning, W B; Snel, J; Kok, A

1998-12-01

Event-related potentials were recorded from 7- to 18-year-old children of alcoholics (COAs, n = 50) and age- and sex-matched control children (n = 50) while they performed a visual selective attention task. The task was to attend selectively to stimuli with a specified color (red or blue) in an attempt to detect the occurrence of target stimuli. COAs manifested a smaller P3b amplitude to attended-target stimuli over the parietal and occipital scalp than did the controls. A more specific analysis indicated that both the attentional relevance and the target properties of the eliciting stimulus determined the observed P3b amplitude differences between COAs and controls. In contrast, no significant group differences were observed in attention-related earlier occurring event-related potential components, referred to as frontal selection positivity, selection negativity, and N2b. These results represent neurophysiological evidence that COAs suffer from deficits at a late (semantic) level of visual selective information processing that are unlikely a consequence of deficits at earlier (sensory) levels of selective processing. The findings support the notion that a reduced visual P3b amplitude in COAs represents a high-level processing dysfunction indicating their increased vulnerability to alcoholism.

Neural Correlates of Individual Differences in Infant Visual Attention and Recognition Memory

PubMed Central

Reynolds, Greg D.; Guy, Maggie W.; Zhang, Dantong

2010-01-01

Past studies have identified individual differences in infant visual attention based upon peak look duration during initial exposure to a stimulus. Colombo and colleagues (e.g., Colombo & Mitchell, 1990) found that infants that demonstrate brief visual fixations (i.e., short lookers) during familiarization are more likely to demonstrate evidence of recognition memory during subsequent stimulus exposure than infants that demonstrate long visual fixations (i.e., long lookers). The current study utilized event-related potentials to examine possible neural mechanisms associated with individual differences in visual attention and recognition memory for 6- and 7.5-month-old infants. Short- and long-looking infants viewed images of familiar and novel objects during ERP testing. There was a stimulus type by looker type interaction at temporal and frontal electrodes on the late slow wave (LSW). Short lookers demonstrated a LSW that was significantly greater in amplitude in response to novel stimulus presentations. No significant differences in LSW amplitude were found based on stimulus type for long lookers. These results indicate deeper processing and recognition memory of the familiar stimulus for short lookers. PMID:21666833

Hippocampal P3-like auditory event-related potentials are disrupted in a rat model of cholinergic degeneration in Alzheimer's disease: reversal by donepezil treatment.

PubMed

Laursen, Bettina; Mørk, Arne; Kristiansen, Uffe; Bastlund, Jesper Frank

2014-01-01

P300 (P3) event-related potentials (ERPs) have been suggested to be an endogenous marker of cognitive function and auditory oddball paradigms are frequently used to evaluate P3 ERPs in clinical settings. Deficits in P3 amplitude and latency reflect some of the neurological dysfunctions related to several psychiatric and neurological diseases, e.g., Alzheimer's disease (AD). However, only a very limited number of rodent studies have addressed the back-translational validity of the P3-like ERPs as suitable markers of cognition. Thus, the potential of rodent P3-like ERPs to predict pro-cognitive effects in humans remains to be fully validated. The current study characterizes P3-like ERPs in the 192-IgG-SAP (SAP) rat model of the cholinergic degeneration associated with AD. Following training in a combined auditory oddball and lever-press setup, rats were subjected to bilateral intracerebroventricular infusion of 1.25 μg SAP or PBS (sham lesion) and recording electrodes were implanted in hippocampal CA1. Relative to sham-lesioned rats, SAP-lesioned rats had significantly reduced amplitude of P3-like ERPs. P3 amplitude was significantly increased in SAP-treated rats following pre-treatment with 1 mg/kg donepezil. Infusion of SAP reduced the hippocampal choline acetyltransferase activity by 75%. Behaviorally defined cognitive performance was comparable between treatment groups. The present study suggests that AD-like deficits in P3-like ERPs may be mimicked by the basal forebrain cholinergic degeneration induced by SAP. SAP-lesioned rats may constitute a suitable model to test the efficacy of pro-cognitive substances in an applied experimental setup.

Cosmic ray modulation

NASA Astrophysics Data System (ADS)

Agarwal Mishra, Rekha; Mishra, Rajesh Kumar

2016-07-01

Propagation of cosmic rays to and inside the heliosphere, encounter an outward moving solar wind with cyclic magnetic field fluctuation and turbulence, causing convection and diffusion in the heliosphere. Cosmic ray counts from the ground ground-based neutron monitors at different cut of rigidity show intensity changes, which are anti-correlated with sunspot numbers. They also lose energy as they propagate towards the Earth and experience various types of modulations due to different solar activity indices. In this work, we study the first three harmonics of cosmic ray intensity on geo-magnetically quiet days over the period 1965-2014 for Beijing, Moscow and Tokyo neutron monitoring stations located at different cut off rigidity. The amplitude of first harmonic remains high for low cutoff rigidity as compared to high cutoff rigidity on quiet days. The diurnal amplitude significantly decreases during solar activity minimum years. The diurnal time of maximum significantly shifts to an earlier time as compared to the corotational direction having different cutoff rigidities. The time of maximum for first harmonic significantly shifts towards later hours and for second harmonic it shifts towards earlier hours at low cutoff rigidity station as compared to the high cut off rigidity station on quiet days. The amplitude of second/third harmonics shows a good positive correlation with solar wind velocity, while the others (i.e. amplitude and phase) have no significant correlation on quiet days. The amplitude and direction of the anisotropy on quiet days does not show any significant dependence on high-speed solar wind streams for these neutron monitoring stations of different cutoff rigidity threshold. Keywords: cosmic ray, cut off rigidity, quiet days, harmonics, amplitude, phase.

Studies of the resonance structure in D0→KS0K±π∓ decays

NASA Astrophysics Data System (ADS)

Aaij, R.; Adeva, B.; Adinolfi, M.; Affolder, A.; Ajaltouni, Z.; Akar, S.; Albrecht, J.; Alessio, F.; Alexander, M.; Ali, S.; Alkhazov, G.; Alvarez Cartelle, P.; Alves, A. A.; Amato, S.; Amerio, S.; Amhis, Y.; An, L.; Anderlini, L.; Anderson, J.; Andreassi, G.; Andreotti, M.; Andrews, J. E.; Appleby, R. B.; Aquines Gutierrez, O.; Archilli, F.; d'Argent, P.; Artamonov, A.; Artuso, M.; Aslanides, E.; Auriemma, G.; Baalouch, M.; Bachmann, S.; Back, J. J.; Badalov, A.; Baesso, C.; Baldini, W.; Barlow, R. J.; Barschel, C.; Barsuk, S.; Barter, W.; Batozskaya, V.; Battista, V.; Bay, A.; Beaucourt, L.; Beddow, J.; Bedeschi, F.; Bediaga, I.; Bel, L. J.; Bellee, V.; Belyaev, I.; Ben-Haim, E.; Bencivenni, G.; Benson, S.; Benton, J.; Berezhnoy, A.; Bernet, R.; Bertolin, A.; Bettler, M.-O.; van Beuzekom, M.; Bien, A.; Bifani, S.; Bird, T.; Birnkraut, A.; Bizzeti, A.; Blake, T.; Blanc, F.; Blouw, J.; Blusk, S.; Bocci, V.; Bondar, A.; Bondar, N.; Bonivento, W.; Borghi, S.; Borsato, M.; Bowcock, T. J. V.; Bowen, E.; Bozzi, C.; Braun, S.; Brett, D.; Britsch, M.; Britton, T.; Brodzicka, J.; Brook, N. H.; Buchanan, E.; Bursche, A.; Buytaert, J.; Cadeddu, S.; Calabrese, R.; Calvi, M.; Calvo Gomez, M.; Campana, P.; Campora Perez, D.; Capriotti, L.; Carbone, A.; Carboni, G.; Cardinale, R.; Cardini, A.; Carniti, P.; Carson, L.; Carvalho Akiba, K.; Casse, G.; Cassina, L.; Castillo Garcia, L.; Cattaneo, M.; Cauet, Ch.; Cavallero, G.; Cenci, R.; Charles, M.; Charpentier, Ph.; Chefdeville, M.; Chen, S.; Cheung, S.-F.; Chiapolini, N.; Chrzaszcz, M.; Cid Vidal, X.; Ciezarek, G.; Clarke, P. E. L.; Clemencic, M.; Cliff, H. V.; Closier, J.; Coco, V.; Cogan, J.; Cogneras, E.; Cogoni, V.; Cojocariu, L.; Collazuol, G.; Collins, P.; Comerma-Montells, A.; Contu, A.; Cook, A.; Coombes, M.; Coquereau, S.; Corti, G.; Corvo, M.; Couturier, B.; Cowan, G. A.; Craik, D. C.; Crocombe, A.; Cruz Torres, M.; Cunliffe, S.; Currie, R.; D'Ambrosio, C.; Dall'Occo, E.; Dalseno, J.; David, P. N. Y.; Davis, A.; De Aguiar Francisco, O.; De Bruyn, K.; De Capua, S.; De Cian, M.; De Miranda, J. M.; De Paula, L.; De Simone, P.; Dean, C.-T.; Decamp, D.; Deckenhoff, M.; Del Buono, L.; Déléage, N.; Demmer, M.; Derkach, D.; Deschamps, O.; Dettori, F.; Dey, B.; Di Canto, A.; Di Ruscio, F.; Dijkstra, H.; Donleavy, S.; Dordei, F.; Dorigo, M.; Dosil Suárez, A.; Dossett, D.; Dovbnya, A.; Dreimanis, K.; Dufour, L.; Dujany, G.; Dupertuis, F.; Durante, P.; Dzhelyadin, R.; Dziurda, A.; Dzyuba, A.; Easo, S.; Egede, U.; Egorychev, V.; Eidelman, S.; Eisenhardt, S.; Eitschberger, U.; Ekelhof, R.; Eklund, L.; El Rifai, I.; Elsasser, Ch.; Ely, S.; Esen, S.; Evans, H. M.; Evans, T.; Falabella, A.; Färber, C.; Farinelli, C.; Farley, N.; Farry, S.; Fay, R.; Ferguson, D.; Fernandez Albor, V.; Ferrari, F.; Ferreira Rodrigues, F.; Ferro-Luzzi, M.; Filippov, S.; Fiore, M.; Fiorini, M.; Firlej, M.; Fitzpatrick, C.; Fiutowski, T.; Fohl, K.; Fol, P.; Fontana, M.; Fontanelli, F.; Forty, R.; Frank, M.; Frei, C.; Frosini, M.; Fu, J.; Furfaro, E.; Gallas Torreira, A.; Galli, D.; Gallorini, S.; Gambetta, S.; Gandelman, M.; Gandini, P.; Gao, Y.; García Pardiñas, J.; Garra Tico, J.; Garrido, L.; Gascon, D.; Gaspar, C.; Gauld, R.; Gavardi, L.; Gazzoni, G.; Gerick, D.; Gersabeck, E.; Gersabeck, M.; Gershon, T.; Ghez, Ph.; Gianı, S.; Gibson, V.; Girard, O. G.; Giubega, L.; Gligorov, V. V.; Göbel, C.; Golubkov, D.; Golutvin, A.; Gomes, A.; Gotti, C.; Grabalosa Gándara, M.; Graciani Diaz, R.; Granado Cardoso, L. A.; Graugés, E.; Graverini, E.; Graziani, G.; Grecu, A.; Greening, E.; Gregson, S.; Griffith, P.; Grillo, L.; Grünberg, O.; Gui, B.; Gushchin, E.; Guz, Yu.; Gys, T.; Hadavizadeh, T.; Hadjivasiliou, C.; Haefeli, G.; Haen, C.; Haines, S. C.; Hall, S.; Hamilton, B.; Han, X.; Hansmann-Menzemer, S.; Harnew, N.; Harnew, S. T.; Harrison, J.; He, J.; Head, T.; Heijne, V.; Hennessy, K.; Henrard, P.; Henry, L.; van Herwijnen, E.; Heß, M.; Hicheur, A.; Hill, D.; Hoballah, M.; Hombach, C.; Hulsbergen, W.; Humair, T.; Hussain, N.; Hutchcroft, D.; Hynds, D.; Idzik, M.; Ilten, P.; Jacobsson, R.; Jaeger, A.; Jalocha, J.; Jans, E.; Jawahery, A.; Jing, F.; John, M.; Johnson, D.; Jones, C. R.; Joram, C.; Jost, B.; Jurik, N.; Kandybei, S.; Kanso, W.; Karacson, M.; Karbach, T. M.; Karodia, S.; Kecke, M.; Kelsey, M.; Kenyon, I. R.; Kenzie, M.; Ketel, T.; Khanji, B.; Khurewathanakul, C.; Klaver, S.; Klimaszewski, K.; Kochebina, O.; Kolpin, M.; Komarov, I.; Koopman, R. F.; Koppenburg, P.; Kozeiha, M.; Kravchuk, L.; Kreplin, K.; Kreps, M.; Krocker, G.; Krokovny, P.; Kruse, F.; Kucewicz, W.; Kucharczyk, M.; Kudryavtsev, V.; Kuonen, A. K.; Kurek, K.; Kvaratskheliya, T.; Lacarrere, D.; Lafferty, G.; Lai, A.; Lambert, D.; Lanfranchi, G.; Langenbruch, C.; Langhans, B.; Latham, T.; Lazzeroni, C.; Le Gac, R.; van Leerdam, J.; Lees, J.-P.; Lefèvre, R.; Leflat, A.; Lefrançois, J.; Leroy, O.; Lesiak, T.; Leverington, B.; Li, Y.; Likhomanenko, T.; Liles, M.; Lindner, R.; Linn, C.; Lionetto, F.; Liu, B.; Liu, X.; Loh, D.; Lohn, S.; Longstaff, I.; Lopes, J. H.; Lucchesi, D.; Lucio Martinez, M.; Luo, H.; Lupato, A.; Luppi, E.; Lupton, O.; Lusiani, A.; Machefert, F.; Maciuc, F.; Maev, O.; Maguire, K.; Malde, S.; Malinin, A.; Manca, G.; Mancinelli, G.; Manning, P.; Mapelli, A.; Maratas, J.; Marchand, J. F.; Marconi, U.; Marin Benito, C.; Marino, P.; Märki, R.; Marks, J.; Martellotti, G.; Martin, M.; Martinelli, M.; Martinez Santos, D.; Martinez Vidal, F.; Martins Tostes, D.; Massafferri, A.; Matev, R.; Mathad, A.; Mathe, Z.; Matteuzzi, C.; Mauri, A.; Maurin, B.; Mazurov, A.; McCann, M.; McCarthy, J.; McNab, A.; McNulty, R.; Meadows, B.; Meier, F.; Meissner, M.; Melnychuk, D.; Merk, M.; Michielin, E.; Milanes, D. A.; Minard, M.-N.; Mitzel, D. S.; Molina Rodriguez, J.; Monroy, I. A.; Monteil, S.; Morandin, M.; Morawski, P.; Mordà, A.; Morello, M. J.; Moron, J.; Morris, A. B.; Mountain, R.; Muheim, F.; Müller, D.; Müller, J.; Müller, K.; Müller, V.; Mussini, M.; Muster, B.; Naik, P.; Nakada, T.; Nandakumar, R.; Nandi, A.; Nasteva, I.; Needham, M.; Neri, N.; Neubert, S.; Neufeld, N.; Neuner, M.; Nguyen, A. D.; Nguyen, T. D.; Nguyen-Mau, C.; Niess, V.; Niet, R.; Nikitin, N.; Nikodem, T.; Novoselov, A.; O'Hanlon, D. P.; Oblakowska-Mucha, A.; Obraztsov, V.; Ogilvy, S.; Okhrimenko, O.; Oldeman, R.; Onderwater, C. J. G.; Osorio Rodrigues, B.; Otalora Goicochea, J. M.; Otto, A.; Owen, P.; Oyanguren, A.; Palano, A.; Palombo, F.; Palutan, M.; Panman, J.; Papanestis, A.; Pappagallo, M.; Pappalardo, L. L.; Pappenheimer, C.; Parkes, C.; Passaleva, G.; Patel, G. D.; Patel, M.; Patrignani, C.; Pearce, A.; Pellegrino, A.; Penso, G.; Pepe Altarelli, M.; Perazzini, S.; Perret, P.; Pescatore, L.; Petridis, K.; Petrolini, A.; Petruzzo, M.; Picatoste Olloqui, E.; Pietrzyk, B.; Pilař, T.; Pinci, D.; Pistone, A.; Piucci, A.; Playfer, S.; Plo Casasus, M.; Poikela, T.; Polci, F.; Poluektov, A.; Polyakov, I.; Polycarpo, E.; Popov, A.; Popov, D.; Popovici, B.; Potterat, C.; Price, E.; Price, J. D.; Prisciandaro, J.; Pritchard, A.; Prouve, C.; Pugatch, V.; Puig Navarro, A.; Punzi, G.; Qian, W.; Quagliani, R.; Rachwal, B.; Rademacker, J. H.; Rama, M.; Rangel, M. S.; Raniuk, I.; Rauschmayr, N.; Raven, G.; Redi, F.; Reichert, S.; Reid, M. M.; dos Reis, A. C.; Ricciardi, S.; Richards, S.; Rihl, M.; Rinnert, K.; Rives Molina, V.; Robbe, P.; Rodrigues, A. B.; Rodrigues, E.; Rodriguez Lopez, J. A.; Rodriguez Perez, P.; Roiser, S.; Romanovsky, V.; Romero Vidal, A.; Ronayne, J. W.; Rotondo, M.; Rouvinet, J.; Ruf, T.; Ruiz, H.; Ruiz Valls, P.; Saborido Silva, J. J.; Sagidova, N.; Sail, P.; Saitta, B.; Salustino Guimaraes, V.; Sanchez Mayordomo, C.; Sanmartin Sedes, B.; Santacesaria, R.; Santamarina Rios, C.; Santimaria, M.; Santovetti, E.; Sarti, A.; Satriano, C.; Satta, A.; Saunders, D. M.; Savrina, D.; Schiller, M.; Schindler, H.; Schlupp, M.; Schmelling, M.; Schmelzer, T.; Schmidt, B.; Schneider, O.; Schopper, A.; Schubiger, M.; Schune, M.-H.; Schwemmer, R.; Sciascia, B.; Sciubba, A.; Semennikov, A.; Serra, N.; Serrano, J.; Sestini, L.; Seyfert, P.; Shapkin, M.; Shapoval, I.; Shcheglov, Y.; Shears, T.; Shekhtman, L.; Shevchenko, V.; Shires, A.; Siddi, B. G.; Silva Coutinho, R.; Silva de Oliveira, L.; Simi, G.; Sirendi, M.; Skidmore, N.; Skwarnicki, T.; Smith, E.; Smith, E.; Smith, I. T.; Smith, J.; Smith, M.; Snoek, H.; Sokoloff, M. D.; Soler, F. J. P.; Soomro, F.; Souza, D.; Souza De Paula, B.; Spaan, B.; Spradlin, P.; Sridharan, S.; Stagni, F.; Stahl, M.; Stahl, S.; Steinkamp, O.; Stenyakin, O.; Sterpka, F.; Stevenson, S.; Stoica, S.; Stone, S.; Storaci, B.; Stracka, S.; Straticiuc, M.; Straumann, U.; Sun, L.; Sutcliffe, W.; Swientek, K.; Swientek, S.; Syropoulos, V.; Szczekowski, M.; Szczypka, P.; Szumlak, T.; T'Jampens, S.; Tayduganov, A.; Tekampe, T.; Teklishyn, M.; Tellarini, G.; Teubert, F.; Thomas, C.; Thomas, E.; van Tilburg, J.; Tisserand, V.; Tobin, M.; Todd, J.; Tolk, S.; Tomassetti, L.; Tonelli, D.; Topp-Joergensen, S.; Torr, N.; Tournefier, E.; Tourneur, S.; Trabelsi, K.; Tran, M. T.; Tresch, M.; Trisovic, A.; Tsaregorodtsev, A.; Tsopelas, P.; Tuning, N.; Ukleja, A.; Ustyuzhanin, A.; Uwer, U.; Vacca, C.; Vagnoni, V.; Valenti, G.; Vallier, A.; Vazquez Gomez, R.; Vazquez Regueiro, P.; Vázquez Sierra, C.; Vecchi, S.; Velthuis, J. J.; Veltri, M.; Veneziano, G.; Vesterinen, M.; Viaud, B.; Vieira, D.; Vieites Diaz, M.; Vilasis-Cardona, X.; Volkov, V.; Vollhardt, A.; Volyanskyy, D.; Voong, D.; Vorobyev, A.; Vorobyev, V.; Voß, C.; de Vries, J. A.; Waldi, R.; Wallace, C.; Wallace, R.; Walsh, J.; Wandernoth, S.; Wang, J.; Ward, D. R.; Watson, N. K.; Websdale, D.; Weiden, A.; Whitehead, M.; Wilkinson, G.; Wilkinson, M.; Williams, M.; Williams, M. P.; Williams, M.; Williams, T.; Wilson, F. F.; Wimberley, J.; Wishahi, J.; Wislicki, W.; Witek, M.; Wormser, G.; Wotton, S. A.; Wright, S.; Wyllie, K.; Xie, Y.; Xu, Z.; Yang, Z.; Yu, J.; Yuan, X.; Yushchenko, O.; Zangoli, M.; Zavertyaev, M.; Zhang, L.; Zhang, Y.; Zhelezov, A.; Zhokhov, A.; Zhong, L.; Zucchelli, S.; LHCb Collaboration

2016-03-01

Amplitude models are applied to studies of resonance structure in D0→KS0K-π+ and D0→KS0K+π- decays using p p collision data corresponding to an integrated luminosity of 3.0 fb-1 collected by the LHCb experiment. Relative magnitude and phase information is determined, and coherence factors and related observables are computed for both the whole phase space and a restricted region of 100 MeV /c2 around the K*(892 )± resonance. Two formulations for the K π S -wave are used, both of which give a good description of the data. The ratio of branching fractions B (D0→KS0K+π- )/B (D0→KS0K-π+ ) is measured to be 0.655 ±0.004 (stat ) ±0.006 (syst ) over the full phase space and 0.370 ±0.003 (stat ) ±0.012 (syst ) in the restricted region. A search for C P violation is performed using the amplitude models and no significant effect is found. Predictions from SU(3) flavor symmetry for K*(892 ) K amplitudes of different charges are compared with the amplitude model results.

Electroexcitation of nucleon resonances from CLAS data on single pion electroproduction

DOE Office of Scientific and Technical Information (OSTI.GOV)

I. G. Aznauryan, V. D. Burkert

2009-11-01

We present results on the electroexcitation of the low mass resonances Delta(1232)P33, N(1440)P11, N(1520)D13, and N(1535)S11 in a wide range of Q2. The results were obtained in the comprehensive analysis of JLab-CLAS data on differential cross sections, longitudinally polarized beam asymmetries, and longitudinal target and beam-target asymmetries for pion electroproduction off the proton. The data were analysed using two conceptually different approaches, fixed-t dispersion relations and a unitary isobar model, allowing us to draw conclusions on the model sensitivity of the obtained electrocoupling amplitudes. The amplitudes for the Delta(1232)P33} show the importance of a meson-cloud contribution to quantitatively explain themore » magnetic dipole strength, as well as the electric and scalar quadrupole transitions. They do not show any tendency of approaching the pQCD regime for Q2<6 GeV2. For the Roper resonance, N(1440)P11, the data provide strong evidence for this state as a predominantly radial excitation of a 3-quark ground state. Measured in pion electroproduction, the transverse helicity amplitude for the N(1535)S11 allowed us to obtain the branching ratios of this state to the piN and etaN channels via comparison to the results extracted from eta electroproduction. The extensive CLAS data also enabled the extraction of the gamma*p -> N(1520)D13 and N(1535)S11 longitudinal helicity amplitudes with good precision.« less

Age-related differences in quality of standing balance using a composite score.

PubMed

Pasma, Jantsje H; Bijlsma, Astrid Y; van der Bij, Mark D W; Arendzen, J Hans; Meskers, Carel G M; Maier, Andrea B

2014-01-01

Age-related differences in standing balance are not detected by testing the ability to maintain balance. Quality of standing balance might be more sensitive to detect age-related differences. To study age-related differences in quality of standing balance, center of pressure (CoP) movement was evaluated using a wide range of CoP parameters in several standing conditions in healthy young and old participants. In 35 healthy young (18-30 years) and 75 healthy old (70-80 years) participants, CoP movement was assessed in eight standing conditions on a force plate, including side-by-side, one-leg, semi-tandem and tandem stance, both with eyes open and eyes closed. Direction-specific CoP composite scores were calculated from standardized single CoP parameters (mean amplitude, amplitude variability, mean velocity, velocity variability and range) in anterior-posterior (AP) and medial-lateral (ML) direction. Linear regression analysis was used to detect age-related differences in single CoP parameters and composite scores - adjusted for gender, height and weight. Overall, single CoP parameters were higher in old compared to young participants, but no single CoP parameter consistently demonstrated the largest effect size for all standing conditions. Age-related differences were demonstrated for CoP composite scores in AP direction (tandem eyes open; semi-tandem eyes closed; p < 0.001). CoP composite scores in ML direction were consistently higher for all standing conditions in old compared to young participants (p < 0.001). CoP composite scores in ML direction were the most consistent parameters to detect age-related differences in quality of standing balance in healthy participants and might be of clinical value to detect subtle changes in quality of standing balance. © 2014 S. Karger AG, Basel

Tibial and fibular nerves evaluation using intraoperative electromyography in rats.

PubMed

Nepomuceno, André Coelho; Politani, Elisa Landucci; Silva, Eduardo Guandelini da; Salomone, Raquel; Longo, Marco Vinicius Losso; Salles, Alessandra Grassi; Faria, José Carlos Marques de; Gemperli, Rolf

2016-08-01

To evaluate a new model of intraoperative electromyographic (EMG) assessment of the tibial and fibular nerves, and its respectives motor units in rats. Eight Wistar rats underwent intraoperative EMG on both hind limbs at two different moments: week 0 and week 12. Supramaximal electrical stimulation applied on sciatic nerve, and compound muscle action potential recorded on the gastrocnemius muscle (GM) and the extensor digitorum longus muscle (EDLM) through electrodes at specifics points. Motor function assessment was performaced through Walking Track Test. Exposing the muscles and nerves for examination did not alter tibial (p=0.918) or fibular (p=0.877) function between the evaluation moments. Electromyography of the GM, innervated by the tibial nerve, revealed similar amplitude (p=0.069) and latency (p=0.256) at week 0 and at 12 weeks, creating a standard of normality. Meanwhile, electromyography of the EDLM, innervated by the fibular nerve, showed significant differences between the amplitudes (p=0.003) and latencies (p=0.021) at the two different moments of observation. Intraoperative electromyography determined and quantified gastrocnemius muscle motor unit integrity, innervated by tibial nerve. Although this study was not useful to, objectively, assess extensor digitorum longus muscle motor unit, innervated by fibular nerve.

Effect of tumor amplitude and frequency on 4D modeling of Vero4DRT system.

PubMed

Miura, Hideharu; Ozawa, Shuichi; Hayata, Masahiro; Tsuda, Shintaro; Yamada, Kiyoshi; Nagata, Yasushi

2017-01-01

An important issue in indirect dynamic tumor tracking with the Vero4DRT system is the accuracy of the model predictions of the internal target position based on surrogate infrared (IR) marker measurement. We investigated the predictive uncertainty of 4D modeling using an external IR marker, focusing on the effect of the target and surrogate amplitudes and periods. A programmable respiratory motion table was used to simulate breathing induced organ motion. Sinusoidal motion sequences were produced by a dynamic phantom with different amplitudes and periods. To investigate the 4D modeling error, the following amplitudes (peak-to-peak: 10-40 mm) and periods (2-8 s) were considered. The 95th percentile 4D modeling error (4D- E 95% ) between the detected and predicted target position ( μ  + 2SD) was calculated to investigate the 4D modeling error. 4D- E 95% was linearly related to the target motion amplitude with a coefficient of determination R 2  = 0.99 and ranged from 0.21 to 0.88 mm. The 4D modeling error ranged from 1.49 to 0.14 mm and gradually decreased with increasing target motion period. We analyzed the predictive error in 4D modeling and the error due to the amplitude and period of target. 4D modeling error substantially increased with increasing amplitude and decreasing period of the target motion.

The effects of dual tasking on handwriting in patients with Parkinson's disease.

PubMed

Broeder, S; Nackaerts, E; Nieuwboer, A; Smits-Engelsman, B C M; Swinnen, S P; Heremans, E

2014-03-28

Previous studies have shown that patients with Parkinson's disease (PD) experience extensive problems during dual tasking. Up to now, dual-task interference in PD has mainly been investigated in the context of gait research. However, the simultaneous performance of two different tasks is also a prerequisite to efficiently perform many other tasks in daily life, including upper limb tasks. To address this issue, this study investigated the effect of a secondary cognitive task on the performance of handwriting in patients with PD. Eighteen PD patients and 11 age-matched controls performed a writing task involving the production of repetitive loops under single- and dual-task conditions. The secondary task consisted of counting high and low tones during writing. The writing tests were performed with two amplitudes (0.6 and 1.0cm) using a writing tablet. Results showed that dual-task performance was affected in PD patients versus controls. Dual tasking reduced writing amplitude in PD patients, but not in healthy controls (p=0.046). Patients' writing size was mainly reduced during the small-amplitude condition (small amplitude p=0.017; large amplitude p=0.310). This suggests that the control of writing at small amplitudes requires more compensational brain-processing recourses in PD and is as such less automatic than writing at large amplitudes. In addition, there was a larger dual-task effect on the secondary task in PD patients than controls (p=0.025). The writing tests on the writing tablet proved highly correlated to daily life writing as measured by the 'Systematic Screening of Handwriting Difficulties' test (SOS-test) and other manual dexterity tasks, particularly during dual-task conditions. Taken together, these results provide additional insights into the motor control of handwriting and the effects of dual tasking during upper limb movements in patients with PD. Copyright © 2014 IBRO. Published by Elsevier Ltd. All rights reserved.

Neural Correlates of Alerting and Orienting Impairment in Multiple Sclerosis Patients

PubMed Central

Vázquez-Marrufo, Manuel; Galvao-Carmona, Alejandro; González-Rosa, Javier J.; Hidalgo-Muñoz, Antonio R.; Borges, Mónica; Ruiz-Peña, Juan Luis; Izquierdo, Guillermo

2014-01-01

Background A considerable percentage of multiple sclerosis patients have attentional impairment, but understanding its neurophysiological basis remains a challenge. The Attention Network Test allows 3 attentional networks to be studied. Previous behavioural studies using this test have shown that the alerting network is impaired in multiple sclerosis. The aim of this study was to identify neurophysiological indexes of the attention impairment in relapsing-remitting multiple sclerosis patients using this test. Results After general slowing had been removed in patients group to isolate the effects of each condition, some behavioral differences between them were obtained. About Contingent Negative Variation, a statistically significant decrement were found in the amplitude for Central and Spatial Cue Conditions for patient group (p<0.05). ANOVAs showed for the patient group a significant latency delay for P1 and N1 components (p<0.05) and a decrease of P3 amplitude for congruent and incongruent stimuli (p<0.01). With regard to correlation analysis, PASAT-3s and SDMT showed significant correlations with behavioral measures of the Attention Network Test (p<0.01) and an ERP parameter (CNV amplitude). Conclusions Behavioral data are highly correlated with the neuropsychological scores and show that the alerting and orienting mechanisms in the patient group were impaired. Reduced amplitude for the Contingent Negative Variation in the patient group suggests that this component could be a physiological marker related to the alerting and orienting impairment in relapsing-remitting multiple sclerosis. P1 and N1 delayed latencies are evidence of the demyelination process that causes impairment in the first steps of the visual sensory processing. Lastly, P3 amplitude shows a general decrease for the pathological group probably indexing a more central impairment. These results suggest that the Attention Network Test give evidence of multiple levels of attention impairment, which could help in the assessment and treatment of relapsing-remitting multiple sclerosis patients. PMID:24820333

Neural correlates of alerting and orienting impairment in multiple sclerosis patients.

PubMed

Vázquez-Marrufo, Manuel; Galvao-Carmona, Alejandro; González-Rosa, Javier J; Hidalgo-Muñoz, Antonio R; Borges, Mónica; Ruiz-Peña, Juan Luis; Izquierdo, Guillermo

2014-01-01

A considerable percentage of multiple sclerosis patients have attentional impairment, but understanding its neurophysiological basis remains a challenge. The Attention Network Test allows 3 attentional networks to be studied. Previous behavioural studies using this test have shown that the alerting network is impaired in multiple sclerosis. The aim of this study was to identify neurophysiological indexes of the attention impairment in relapsing-remitting multiple sclerosis patients using this test. After general slowing had been removed in patients group to isolate the effects of each condition, some behavioral differences between them were obtained. About Contingent Negative Variation, a statistically significant decrement were found in the amplitude for Central and Spatial Cue Conditions for patient group (p<0.05). ANOVAs showed for the patient group a significant latency delay for P1 and N1 components (p<0.05) and a decrease of P3 amplitude for congruent and incongruent stimuli (p<0.01). With regard to correlation analysis, PASAT-3s and SDMT showed significant correlations with behavioral measures of the Attention Network Test (p<0.01) and an ERP parameter (CNV amplitude). Behavioral data are highly correlated with the neuropsychological scores and show that the alerting and orienting mechanisms in the patient group were impaired. Reduced amplitude for the Contingent Negative Variation in the patient group suggests that this component could be a physiological marker related to the alerting and orienting impairment in relapsing-remitting multiple sclerosis. P1 and N1 delayed latencies are evidence of the demyelination process that causes impairment in the first steps of the visual sensory processing. Lastly, P3 amplitude shows a general decrease for the pathological group probably indexing a more central impairment. These results suggest that the Attention Network Test give evidence of multiple levels of attention impairment, which could help in the assessment and treatment of relapsing-remitting multiple sclerosis patients.

Diagnosing the Role of Alfvén Waves in Magnetosphere-Ionosphere Coupling: Swarm Observations of Large Amplitude Nonstationary Magnetic Perturbations During an Interval of Northward IMF

NASA Astrophysics Data System (ADS)

Pakhotin, I. P.; Mann, I. R.; Lysak, R. L.; Knudsen, D. J.; Gjerloev, J. W.; Rae, I. J.; Forsyth, C.; Murphy, K. R.; Miles, D. M.; Ozeke, L. G.; Balasis, G.

2018-01-01

High-resolution multispacecraft Swarm data are used to examine magnetosphere-ionosphere coupling during a period of northward interplanetary magnetic field (IMF) on 31 May 2014. The observations reveal a prevalence of unexpectedly large amplitude (>100 nT) and time-varying magnetic perturbations during the polar passes, with especially large amplitude magnetic perturbations being associated with large-scale downward field-aligned currents. Differences between the magnetic field measurements sampled at 50 Hz from Swarm A and C, approximately 10 s apart along track, and the correspondence between the observed electric and magnetic fields at 16 samples per second, provide significant evidence for an important role for Alfvén waves in magnetosphere-ionosphere coupling even during northward IMF conditions. Spectral comparison between the wave E- and B-fields reveals a frequency-dependent phase difference and amplitude ratio consistent with interference between incident and reflected Alfvén waves. At low frequencies, the E/B ratio is in phase with an amplitude determined by the Pedersen conductance. At higher frequencies, the amplitude and phase change as a function of frequency in good agreement with an ionospheric Alfvén resonator model including Pedersen conductance effects. Indeed, within this Alfvén wave incidence, reflection, and interference paradigm, even quasi-static field-aligned currents might be reasonably interpreted as very low frequency (ω → 0) Alfvén waves. Overall, our results not only indicate the importance of Alfvén waves for magnetosphere-ionosphere coupling but also demonstrate a method for using Swarm data for the innovative experimental diagnosis of Pedersen conductance from low-Earth orbit satellite measurements.

Connecting physical resonant amplitudes and lattice QCD

DOE PAGES

Bolton, Daniel R.; Briceno, Raul A.; Wilson, David J.

2016-03-18

Here, we present a determination of the isovector,more » $P$-wave $$\\pi\\pi$$ scattering phase shift obtained by extrapolating recent lattice QCD results from the Hadron Spectrum Collaboration using $$m_\\pi =236$$ MeV. The finite volume spectra are described using extensions of L\\"uscher's method to determine the infinite volume Unitarized Chiral Perturbation Theory scattering amplitude. We exploit the pion mass dependence of this effective theory to obtain the scattering amplitude at $$m_\\pi= 140$$ MeV. The scattering phase shift is found to be in good agreement with experiment up to center of mass energies of 1.2 GeV. The analytic continuation of the scattering amplitude to the complex plane yields a $$\\rho$$-resonance pole at $$E_\\rho= \\left[755(2)(1)(^{20}_{02})-\\frac{i}{2}\\,129(3)(1)(^{7}_{1})\\right]~{\\rm MeV}$$. The techniques presented illustrate a possible pathway towards connecting lattice QCD observables of few-body, strongly interacting systems to experimentally accessible quantities.« less

Circadian course of the P300 ERP in patients with amyotrophic lateral sclerosis - implications for brain-computer interfaces (BCI).

PubMed

Erlbeck, Helena; Mochty, Ursula; Kübler, Andrea; Real, Ruben G L

2017-01-07

Accidents or neurodegenerative diseases like amyotrophic lateral sclerosis (ALS) can lead to progressing, extensive, and complete paralysis leaving patients aware but unable to communicate (locked-in state). Brain-computer interfaces (BCI) based on electroencephalography represent an important approach to establish communication with these patients. The most common BCI for communication rely on the P300, a positive deflection arising in response to rare events. To foster broader application of BCIs for restoring lost function, also for end-users with impaired vision, we explored whether there were specific time windows during the day in which a P300 driven BCI should be preferably applied. The present study investigated the influence of time of the day and modality (visual vs. auditory) on P300 amplitude and latency. A sample of 14 patients (end-users) with ALS and 14 healthy age matched volunteers participated in the study and P300 event-related potentials (ERP) were recorded at four different times (10, 12 am, 2, & 4 pm) during the day. Results indicated no differences in P300 amplitudes or latencies between groups (ALS patients v. healthy participants) or time of measurement. In the auditory condition, latencies were shorter and amplitudes smaller as compared to the visual condition. Our findings suggest applicability of EEG/BCI sessions in patients with ALS throughout normal waking hours. Future studies using actual BCI systems are needed to generalize these findings with regard to BCI effectiveness/efficiency and other times of day.

The Relationship Between Engagement and Neurophysiological Measures of Attention in Motion-Controlled Video Games: A Randomized Controlled Trial.

PubMed

Leiker, Amber M; Miller, Matthew; Brewer, Lauren; Nelson, Monica; Siow, Maria; Lohse, Keith

2016-04-21

Video games and virtual environments continue to be the subject of research in health sciences for their capacity to augment practice through user engagement. Creating game mechanics that increase user engagement may have indirect benefits on learning (ie, engaged learners are likely to practice more) and may also have direct benefits on learning (ie, for a fixed amount of practice, engaged learners show superior retention of information or skills). To manipulate engagement through the aesthetic features of a motion-controlled video game and measure engagement's influence on learning. A group of 40 right-handed participants played the game under two different conditions (game condition or sterile condition). The mechanics of the game and the amount of practice were constant. During practice, event-related potentials (ERPs) to task-irrelevant probe tones were recorded during practice as an index of participants' attentional reserve. Participants returned for retention and transfer testing one week later. Although both groups improved in the task, there was no difference in the amount of learning between the game and sterile groups, countering previous research. A new finding was a statistically significant relationship between self-reported engagement and the amplitude of the early-P3a (eP3a) component of the ERP waveform, such that participants who reported higher levels of engagement showed a smaller eP3a (beta=-.08, P=.02). This finding provides physiological data showing that engagement elicits increased information processing (reducing attentional reserve), which yields new insight into engagement and its underlying neurophysiological properties. Future studies may objectively index engagement by quantifying ERPs (specifically the eP3a) to task-irrelevant probes.

The Relationship Between Engagement and Neurophysiological Measures of Attention in Motion-Controlled Video Games: A Randomized Controlled Trial

PubMed Central

Brewer, Lauren; Nelson, Monica; Siow, Maria

2016-01-01

Background Video games and virtual environments continue to be the subject of research in health sciences for their capacity to augment practice through user engagement. Creating game mechanics that increase user engagement may have indirect benefits on learning (ie, engaged learners are likely to practice more) and may also have direct benefits on learning (ie, for a fixed amount of practice, engaged learners show superior retention of information or skills). Objective To manipulate engagement through the aesthetic features of a motion-controlled video game and measure engagement’s influence on learning. Methods A group of 40 right-handed participants played the game under two different conditions (game condition or sterile condition). The mechanics of the game and the amount of practice were constant. During practice, event-related potentials (ERPs) to task-irrelevant probe tones were recorded during practice as an index of participants’ attentional reserve. Participants returned for retention and transfer testing one week later. Results Although both groups improved in the task, there was no difference in the amount of learning between the game and sterile groups, countering previous research. A new finding was a statistically significant relationship between self-reported engagement and the amplitude of the early-P3a (eP3a) component of the ERP waveform, such that participants who reported higher levels of engagement showed a smaller eP3a (beta=−.08, P=.02). Conclusions This finding provides physiological data showing that engagement elicits increased information processing (reducing attentional reserve), which yields new insight into engagement and its underlying neurophysiological properties. Future studies may objectively index engagement by quantifying ERPs (specifically the eP3a) to task-irrelevant probes. PMID:27103052

The Location of Peak Upper Trapezius Muscle Activity During Submaximal Contractions is not Associated With the Location of Myofascial Trigger Points: New Insights Revealed by High-density Surface EMG.

PubMed

Barbero, Marco; Falla, Deborah; Mafodda, Luca; Cescon, Corrado; Gatti, Roberto

2016-12-01

To apply topographical mapping of the electromyography (EMG) amplitude recorded from the upper trapezius muscle to evaluate the distribution of activity and the location of peak activity during a shoulder elevation task in participants with and without myofascial pain and myofascial trigger points (MTrP) and compare this location with the site of the MTrP. Thirteen participants with myofascial pain and MTrP in the upper trapezius muscle and 12 asymptomatic individuals participated. High-density surface EMG was recorded from the upper trapezius muscle using a matrix of 64 surface electrodes aligned with an anatomic landmark system (ALS). Each participant performed a shoulder elevation task consisting of a series of 30 s ramped contractions to 15% or 60% of their maximal voluntary contraction (MVC) force. Topographical maps of the EMG average rectified value were computed and the peak EMG amplitude during the ramped contractions was identified and its location determined with respect to the ALS. The location of the MTrP was also determined relative to the ALS and Spearman correlation coefficients were used to examine the relationship between MTrP and peak EMG amplitude location. The location of the peak EMG amplitude was significantly (P<0.05) different between groups (participants with pain/MTrP: -0.32±1.2 cm at 15% MVC and -0.35±0.9 cm at 60% MVC relative to the ALS; asymptomatic participants: 1.0±1.3 cm at 15% MVC and 1.3±1.1 cm relative to the ALS). However, no correlation was observed between the position of the MTrP and peak EMG amplitude during the ramped contractions at either force level (15%: rs=0.039, P=0.9; 60%: rs=-0.087, P=0.778). People with myofascial pain and MTrP displayed a caudal shift of the distribution of upper trapezius muscle activity compared with asymptomatic individuals during a submaximal shoulder elevation task. For the first time, we show that the location of peak muscle activity is not associated with the location of the MTrP.

Validating and calibrating the Nintendo Wii balance board to derive reliable center of pressure measures.

PubMed

Leach, Julia M; Mancini, Martina; Peterka, Robert J; Hayes, Tamara L; Horak, Fay B

2014-09-29

The Nintendo Wii balance board (WBB) has generated significant interest in its application as a postural control measurement device in both the clinical and (basic, clinical, and rehabilitation) research domains. Although the WBB has been proposed as an alternative to the "gold standard" laboratory-grade force plate, additional research is necessary before the WBB can be considered a valid and reliable center of pressure (CoP) measurement device. In this study, we used the WBB and a laboratory-grade AMTI force plate (AFP) to simultaneously measure the CoP displacement of a controlled dynamic load, which has not been done before. A one-dimensional inverted pendulum was displaced at several different displacement angles and load heights to simulate a variety of postural sway amplitudes and frequencies (<1 Hz). Twelve WBBs were tested to address the issue of inter-device variability. There was a significant effect of sway amplitude, frequency, and direction on the WBB's CoP measurement error, with an increase in error as both sway amplitude and frequency increased and a significantly greater error in the mediolateral (ML) (compared to the anteroposterior (AP)) sway direction. There was no difference in error across the 12 WBB's, supporting low inter-device variability. A linear calibration procedure was then implemented to correct the WBB's CoP signals and reduce measurement error. There was a significant effect of calibration on the WBB's CoP signal accuracy, with a significant reduction in CoP measurement error (quantified by root-mean-squared error) from 2-6 mm (before calibration) to 0.5-2 mm (after calibration). WBB-based CoP signal calibration also significantly reduced the percent error in derived (time-domain) CoP sway measures, from -10.5% (before calibration) to -0.05% (after calibration) (percent errors averaged across all sway measures and in both sway directions). In this study, we characterized the WBB's CoP measurement error under controlled, dynamic conditions and implemented a linear calibration procedure for WBB CoP signals that is recommended to reduce CoP measurement error and provide more reliable estimates of time-domain CoP measures. Despite our promising results, additional work is necessary to understand how our findings translate to the clinical and rehabilitation research domains. Once the WBB's CoP measurement error is fully characterized in human postural sway (which differs from our simulated postural sway in both amplitude and frequency content), it may be used to measure CoP displacement in situations where lower accuracy and precision is acceptable.

Validating and Calibrating the Nintendo Wii Balance Board to Derive Reliable Center of Pressure Measures

PubMed Central

Leach, Julia M.; Mancini, Martina; Peterka, Robert J.; Hayes, Tamara L.; Horak, Fay B.

2014-01-01

The Nintendo Wii balance board (WBB) has generated significant interest in its application as a postural control measurement device in both the clinical and (basic, clinical, and rehabilitation) research domains. Although the WBB has been proposed as an alternative to the “gold standard” laboratory-grade force plate, additional research is necessary before the WBB can be considered a valid and reliable center of pressure (CoP) measurement device. In this study, we used the WBB and a laboratory-grade AMTI force plate (AFP) to simultaneously measure the CoP displacement of a controlled dynamic load, which has not been done before. A one-dimensional inverted pendulum was displaced at several different displacement angles and load heights to simulate a variety of postural sway amplitudes and frequencies (<1 Hz). Twelve WBBs were tested to address the issue of inter-device variability. There was a significant effect of sway amplitude, frequency, and direction on the WBB's CoP measurement error, with an increase in error as both sway amplitude and frequency increased and a significantly greater error in the mediolateral (ML) (compared to the anteroposterior (AP)) sway direction. There was no difference in error across the 12 WBB's, supporting low inter-device variability. A linear calibration procedure was then implemented to correct the WBB's CoP signals and reduce measurement error. There was a significant effect of calibration on the WBB's CoP signal accuracy, with a significant reduction in CoP measurement error (quantified by root-mean-squared error) from 2–6 mm (before calibration) to 0.5–2 mm (after calibration). WBB-based CoP signal calibration also significantly reduced the percent error in derived (time-domain) CoP sway measures, from −10.5% (before calibration) to −0.05% (after calibration) (percent errors averaged across all sway measures and in both sway directions). In this study, we characterized the WBB's CoP measurement error under controlled, dynamic conditions and implemented a linear calibration procedure for WBB CoP signals that is recommended to reduce CoP measurement error and provide more reliable estimates of time-domain CoP measures. Despite our promising results, additional work is necessary to understand how our findings translate to the clinical and rehabilitation research domains. Once the WBB's CoP measurement error is fully characterized in human postural sway (which differs from our simulated postural sway in both amplitude and frequency content), it may be used to measure CoP displacement in situations where lower accuracy and precision is acceptable. PMID:25268919

Reward Promotes Self-Face Processing: An Event-Related Potential Study

PubMed Central

Zhan, Youlong; Chen, Jie; Xiao, Xiao; Li, Jin; Yang, Zilu; Fan, Wei; Zhong, Yiping

2016-01-01

The present study adopted a reward-priming paradigm to investigate whether and how monetary reward cues affected self-face processing. Event-related potentials were recorded during judgments of head orientation of target faces (self, friend, and stranger), with performance associated with a monetary reward. The results showed self-faces elicited larger N2 mean amplitudes than other-faces, and mean N2 amplitudes increased after monetary reward as compared with no reward cue. Moreover, an interaction effect between cue type and face type was observed for the P3 component, suggesting that both self-faces and friend-faces elicited larger P3 mean amplitudes than stranger-faces after no reward cue, with no significant difference between self-faces and friend-faces under this condition. However, self-faces elicited larger P3 mean amplitudes than friend-faces when monetary reward cues were provided. Interestingly, the enhancement of reward on friend-faces processing was observed at late positive potentials (LPP; 450–600 ms), suggesting that the LPP difference between friend-faces and stranger-faces was enhanced with monetary reward cues. Thus, we found that the enhancement effect of reward on self-relevant processing occurred at the later stages, but not at the early stage. These findings suggest that the activation of the reward expectations can enhance self-face processing, yielding a robust and sustained modulation over their overlapped brain areas where reward and self-relevant processing mechanisms may operate together. PMID:27242637

[Visual perception of Kanji characters and complicated figures. Part 3. Visual P300 event-related potentials in patients with attention deficit/hyperactivity disorders].

PubMed

Shirane, Seiko; Inagaki, Masumi; Sata, Yoshimi; Kaga, Makiko

2004-07-01

In order to evaluate visual perception, the P300 event-related potentials (ERPs) for visual oddball tasks were recorded in 11 patients with attention deficit/hyperactivity disorders (AD/HD), 12 with mental retardation (MR) and 14 age-matched healthy controls. With the aim of revealing trial-to-trial variabilities which are neglected by investigating averaged ERPs, single sweep P300s (ss-P300s) were assessed in addition to averaged P300. There were no significant differences of averaged P300 latency and amplitude between controls and AD/HD patients. AD/HD patients showed an increased variability in the amplitude of ss-P300s, while MR patient showed an increased variability in latency. These findings suggest that in AD/HD patients general attention is impaired to a larger extent than selective attention and visual perception.

[Effect of acupuncture on pattern-visual evoked potential in rats with monocular visual deprivation].

PubMed

Yan, Xing-Ke; Dong, Li-Li; Liu, An-Guo; Wang, Jun-Yan; Ma, Chong-Bing; Zhu, Tian-Tian

2013-08-01

To explore electrophysiology mechanism of acupuncture for treatment and prevention of visual deprivation effect. Eighteen healthy 15-day Evans rats were randomly divided into a normal group, a model group and an acupuncture group, 6 rats in each one. Deprivation amblyopia model was established by monocular eyelid suture in the model group and acupuncture group. Acupuncture was applied at "Jingming" (BL 1), "Chengqi" (ST 1), "Qiuhou" (EX-HN 7) and "Cuanzhu" (BL 2) in the acupuncture group. The bilateral acupoints were selected alternately, one side for a day, and totally 14 days were required. The effect of acupuncture on visual evoked potential in different spatial frequencies was observed. Under three different kinds of spatial frequencies of 2 X 2, 4 X 4 and 8 X 8, compared with normal group, there was obvious visual deprivation effect in the model group where P1 peak latency was delayed (P<0.01) while N1 -P1 amplitude value was decreased (P<0.01). Compared with model group, P1 peak latency was obviously ahead of time (P<0.01) while N1-P1 amplitude value was increased (P<0.01) in the acupuncture group, there was no statistical significance compared with normal group (P>0.05). Under spatial frequency of 4 X 4, N1-P1 amplitude value was maximum in the normal group and acupuncture group. With this spatial frequency the rat's eye had best resolving ability, indicating it could be the best spatial frequency for rat visual system. The visual system has obvious electrophysiology plasticity in sensitive period. Acupuncture treatment could adjust visual deprivation-induced suppression and slow of visual response in order to antagonism deprivation effect.

The sensitivity of the atmospheric branch of the global water cycle to temperature fluctuations at synoptic to decadal time-scales in different satellite- and model-based products

NASA Astrophysics Data System (ADS)

Nogueira, Miguel

2018-02-01

Spectral analysis of global-mean precipitation, P, evaporation, E, precipitable water, W, and surface temperature, Ts, revealed significant variability from sub-daily to multi-decadal time-scales, superposed on high-amplitude diurnal and yearly peaks. Two distinct regimes emerged from a transition in the spectral exponents, β. The weather regime covering time-scales < 10 days with β ≥ 1; and the macroweather regime extending from a few months to a few decades with 0 <β <1. Additionally, the spectra showed a generally good statistical agreement amongst several different model- and satellite-based datasets. Detrended cross-correlation analysis (DCCA) revealed three important results which are robust across all datasets: (1) Clausius-Clapeyron (C-C) relationship is the dominant mechanism of W non-periodic variability at multi-year time-scales; (2) C-C is not the dominant control of W, P or E non-periodic variability at time-scales below about 6 months, where the weather regime is approached and other mechanisms become important; (3) C-C is not a dominant control for P or E over land throughout the entire time-scale range considered. Furthermore, it is suggested that the atmosphere and oceans start to act as a single coupled system at time-scales > 1-2 years, while at time-scales < 6 months they are not the dominant drivers of each other. For global-ocean and full-globe averages, ρDCCA showed large spread of the C-C importance for P and E variability amongst different datasets at multi-year time-scales, ranging from negligible (< 0.3) to high ( 0.6-0.8) values. Hence, state-of-the-art climate datasets have significant uncertainties in the representation of macroweather precipitation and evaporation variability and its governing mechanisms.

Interside Latency Differences in Brainstem Auditory and Somatosensory Evoked Potentials. Defining Upper Limits to Determine Asymmetry.

PubMed

Moncho, Dulce; Poca, Maria A; Minoves, Teresa; Ferré, Alejandro; Sahuquillo, Juan

2015-10-01

Limits of the interside differences are invaluable when interpreting asymmetry in brainstem auditory evoked potentials and somatosensory evoked potentials (SEP) recordings. The aim of this study was to analyze the normal upper limits of interside latency differences of brainstem auditory evoked potentials and SEP from the posterior tibial nerve and median nerve to determine asymmetry. The authors performed a prospective study in 56 healthy subjects aged 15 to 64 years with no neurological or hearing disorders. They analyzed (1) the latencies of I, III, and V waves and I-III, III-V, and I-V intervals and the amplitude ratios V/I and IV/I for brainstem auditory evoked potentials bilaterally; (2) the latencies of N8, N22, N28, and P37 waves and the interval N22-P37 and the amplitude P37 for posterior tibial nerve SEP bilaterally; and (3) the latencies and amplitudes of N9, N13, and N20 waves and N9-N13 and N13-N20 intervals for median nerve SEP bilaterally. The interside differences for these parameters were calculated and analyzed. The authors obtained an upper limit for the interside latency differences from brainstem auditory evoked potentials that was significantly lower than the previously published data. However, the upper limits of interside latency differences for SEP were similar to those previously reported. The findings of this study should be considered when laboratories analyze asymmetry using the normative data published by another center, however temporarily, in organizing new laboratories.

Two Simon tasks with different sources of conflict: an ERP study of motion- and location-based compatibility effects.

PubMed

Galashan, Daniela; Wittfoth, Matthias; Fehr, Thorsten; Herrmann, Manfred

2008-07-01

Behavioral and electrophysiological correlates of two Simon tasks were examined using comparable stimuli but different task-irrelevant and conflict-inducing stimulus features. Whereas target shape was always the task-relevant stimulus attribute, either target location (location-based task) or motion direction within the target stimuli (motion-based task) was used as a source of conflict. Data from ten healthy participants who performed both tasks are presented. In the motion-based task the incompatible condition showed smaller P300 amplitudes at Pz than the compatible condition and the location-based task yielded a trend towards a reduced P300 amplitude in the incompatible condition. For both tasks, no P300 latency differences between the conditions were found at Pz. The results suggest that the motion-based task elicits behavioral and electrophysiological effects comparable with regular Simon tasks. As all stimuli in the motion-based Simon task were presented centrally the present data strongly argue against the attention-shifting account as an explanatory approach.

Baseline Brain Activity Changes in Patients With Single and Relapsing Optic Neuritis.

PubMed

Ren, Zhuoqiong; Liu, Yaou; Li, Kuncheng; Duan, Yunyun; Jing, Huang; Liang, Peipeng; Sun, Zheng; Zhang, Xiaojun; Mao, Bei

2018-01-01

Purpose : To investigate spontaneous brain activity amplitude alterations in single and relapsing optic neuritis (sON and rON, respectively) and their relationships with clinical variables. Methods : In total, 42 patients with sON, 35 patients with rON and 50 healthy volunteers were recruited. Resting-state functional Magnetic Resonance Imaging (rs-fMRI) scans were acquired for all participants and compared to investigate the changes in the amplitude of low-frequency fluctuations (ALFFs) among the three groups. The relationships between the ALFFs in regions with significant differences in the groups and clinical variables, including the logarithm of minimal angle of resolution (LogMAR), Expanded Disability Status Scale (EDSS) score and disease duration, were further explored. Results : Compared with healthy volunteers, the sON and rON patients showed significantly decreased ALFFs in several regions of the occipital and temporal lobes (i.e., inferior occipital gyrus and superior temporal gyrus; corrected p < 0.01 using AlphaSim). The sON patients showed significantly increased ALFFs in the left caudate and certain regions in the frontal lobes (i.e., medial frontal gyrus), whereas the rON patients showed increased ALFFs in the bilateral inferior temporal gyrus and left medial frontal gyrus (corrected p < 0.01 using AlphaSim). Significantly decreased ALFFs were observed in the right inferior parietal lobule (IPL), left posterior cingulate and precuneus in the rON patients compared with those in the sON patients (corrected p < 0.01 using AlphaSim). Significant correlations were observed between the disease duration and ALFF in the left middle temporal gyrus, left inferior occipital gyrus, right lingual gyrus and right IPL ( p < 0.05). Conclusion : Functional impairment and adaptation occurred in both the sON and rON patients. Impairment mainly involved the occipital cortex, and functional adaptions predominantly occurred in the frontal lobe. Functional damage was more severe in the rON patients than in the sON patients and correlated with the disease duration.

Cortical Auditory Evoked Potentials with Simple (Tone Burst) and Complex (Speech) Stimuli in Children with Cochlear Implant

PubMed Central

Martins, Kelly Vasconcelos Chaves; Gil, Daniela

2017-01-01

Introduction  The registry of the component P1 of the cortical auditory evoked potential has been widely used to analyze the behavior of auditory pathways in response to cochlear implant stimulation. Objective  To determine the influence of aural rehabilitation in the parameters of latency and amplitude of the P1 cortical auditory evoked potential component elicited by simple auditory stimuli (tone burst) and complex stimuli (speech) in children with cochlear implants. Method  The study included six individuals of both genders aged 5 to 10 years old who have been cochlear implant users for at least 12 months, and who attended auditory rehabilitation with an aural rehabilitation therapy approach. Participants were submitted to research of the cortical auditory evoked potential at the beginning of the study and after 3 months of aural rehabilitation. To elicit the responses, simple stimuli (tone burst) and complex stimuli (speech) were used and presented in free field at 70 dB HL. The results were statistically analyzed, and both evaluations were compared. Results  There was no significant difference between the type of eliciting stimulus of the cortical auditory evoked potential for the latency and the amplitude of P1. There was a statistically significant difference in the P1 latency between the evaluations for both stimuli, with reduction of the latency in the second evaluation after 3 months of auditory rehabilitation. There was no statistically significant difference regarding the amplitude of P1 under the two types of stimuli or in the two evaluations. Conclusion  A decrease in latency of the P1 component elicited by both simple and complex stimuli was observed within a three-month interval in children with cochlear implant undergoing aural rehabilitation. PMID:29018498

pO{sub 2} Fluctuation Pattern and Cycling Hypoxia in Human Cervical Carcinoma and Melanoma Xenografts

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ellingsen, Christine; Ovrebo, Kirsti Marie; Galappathi, Kanthi

2012-07-15

Purpose: Blood perfusion in tumors is spatially and temporally heterogeneous, resulting in local fluctuations in tissue oxygen tension (pO{sub 2}) and tissue regions showing cycling hypoxia. In this study, we investigated whether the pO{sub 2} fluctuation pattern and the extent of cycling hypoxia differ between tumor types showing high (e.g., cervical carcinoma xenograft) and low (e.g., melanoma xenograft) fractions of connective tissue-associated blood vessels. Methods and Materials: Two cervical carcinoma lines (CK-160 and TS-415) and two melanoma lines (A-07 and R-18) transplanted into BALB/c nu/nu mice were included in the study. Tissue pO{sub 2} was measured simultaneously in two positionsmore » in each tumor by using a two-channel OxyLite fiber-optic oxygen-sensing device. The extent of acute and chronic hypoxia was assessed by combining a radiobiological and a pimonidazole-based immunohistochemical assay of tumor hypoxia. Results: The proportion of tumor regions showing pO{sub 2} fluctuations, the pO{sub 2} fluctuation frequency in these regions, and the relative amplitude of the pO{sub 2} fluctuations were significantly higher in the melanoma xenografts than in the cervical carcinoma xenografts. Cervical carcinoma and melanoma xenografts did not differ significantly in the fraction of acutely hypoxic cells or the fraction of chronically hypoxic cells. However, the ratio between fraction of acutely hypoxic cells and fraction of chronically hypoxic cells was significantly higher in melanoma than in cervical carcinoma xenografts. Conclusions: Temporal heterogeneity in blood flow and tissue pO{sub 2} in tumors may depend on tumor histology. Connective tissue surrounding microvessels may stabilize blood flow and pO{sub 2} and, thus, protect tumor tissue from cycling hypoxia.« less

Amplitude Analysis and Modeling of Regional Phases in PNE Profiles in Northern Eurasia and Seismic Regionalization

DTIC Science & Technology

2006-06-30

ratios (Lg/Pn, Lg/Pg, Lg/Sn, and Lg/ Pcod ,), a constant window length was used to measure the phase amplitudes. The phases were identified by correlating...log(ýo-) = (Yp + yp,,o-dLg)(log( 2) -log ))+Q( + p.o-71Lg)(x 2 - (2.9) ’ 4 pcod ,2 APCoda Therefore, the difference of log(ALg/Apcoda) between

[Use of quantitative electroencephalogram in patients with septic shock].

PubMed

Ma, Yujie; Ouyang, Bin; Guan, Xiangdong

2016-01-19

To observe the quantitative electroencephalogram (qEEG) characteristics of the patients with septic shock in intensive care unit (ICU), and to find the early presence and severity of septic-associated encephalopathy (SAE) in these patients. During November 2014 to August 2015, 26 cases with septic shock were included from the ICU of the First Affiliated Hospital, Sun Yat-sen University.During the same period, 14 healthy volunteers were included as control. The brain function instrument was used to monitor the patients by the bed, placing leads as the internationally used 10-20 system, bipolar longitudinal F3-P3, F4-P4 four channels, and then consecutive clips of 5 minutes was chosen, using the average value of the clips, the amplitude integrated electroencephalogram (aEEG), relative frequency band energy, spectrum entropy, relative alpha ariability to carry out statistical analysis.And the qEEG features of septic shock patients with different Glasgow coma scale (GCS) levels were also analyzed. (1) 96% of the patients with septic shock had EEG abnormalities.Alpha frequency band energy, alpha ariability, aEEG amplitude, spectrum entropy decreased significantly (P<0.05=, while the delta frequency band energy significantly increased (P<0.05=. (2) aEEG amplitude decline appeared in 34% of patients with septic shock, and within the septic shock groups, amplitude decreased significantly (P<0.05= in patients with GCS under five. Patients with septic shock tends to have diffuse inhibition in EEG, and the inhibition degree can reflect cerebral lesion degree; changes of EEG frequency as early warning indicators of brain damage are sensitive, and the decline of amplitude often indicates critical injury.

Validation of Mismatch Negativity and P3a for Use in Multi-Site Studies of Schizophrenia: Characterization of Demographic, Clinical, Cognitive, and Functional Correlates in COGS-2

PubMed Central

Light, Gregory A.; Swerdlow, Neal R.; Thomas, Michael L.; Calkins, Monica E.; Green, Michael F.; Greenwood, Tiffany A.; Gur, Raquel E.; Gur, Ruben C.; Lazzeroni, Laura C.; Nuechterlein, Keith H.; Pela, Marlena; Radant, Allen D.; Seidman, Larry J.; Sharp, Richard F.; Siever, Larry J.; Silverman, Jeremy M.; Sprock, Joyce; Stone, William S.; Sugar, Catherine A.; Tsuang, Debby W.; Tsuang, Ming T.; Braff, David L.; Turetsky, Bruce I.

2014-01-01

Mismatch negativity (MMN) and P3a are auditory event-related potential (ERP) components that show robust deficits in schizophrenia (SZ) patients and exhibit qualities of endophenotypes, including substantial heritability, test-retest reliability, and trait-like stability. These measures also fulfill criteria for use as cognition and function-linked biomarkers in outcome studies, but have not yet been validated for use in large-scale multi-site clinical studies. This study tested the feasibility of adding MMN and P3a to the ongoing Consortium on the Genetics of Schizophrenia (COGS) study. The extent to which demographic, clinical, cognitive, and functional characteristics contribute to variability in MMN and P3a amplitudes was also examined. Participants (HCS n=824, SZ n=966) underwent testing at 5 geographically distributed COGS laboratories. Valid ERP data was obtained from 91% of HCS and 91% of SZ patients. Highly significant MMN (d=0.96) and P3a (d=0.93) amplitude reductions were observed in SZ patients, comparable in magnitude to those observed in single-lab studies with no appreciable differences across laboratories. Demographic characteristics accounted for 26% and 18% of the variance in MMN and P3a amplitudes, respectively. Significant relationships were observed among demographically-adjusted MMN and P3a measures and medication status as well as several clinical, cognitive, and functional characteristics of the SZ patients. This study demonstrates that MMN and P3a ERP biomarkers can be feasibly used in multi-site clinical studies. As with many clinical tests of brain function, demographic factors contribute to MMN and P3a amplitudes and should be carefully considered in future biomarker-informed clinical studies. PMID:25449710

Validation of mismatch negativity and P3a for use in multi-site studies of schizophrenia: characterization of demographic, clinical, cognitive, and functional correlates in COGS-2.

PubMed

Light, Gregory A; Swerdlow, Neal R; Thomas, Michael L; Calkins, Monica E; Green, Michael F; Greenwood, Tiffany A; Gur, Raquel E; Gur, Ruben C; Lazzeroni, Laura C; Nuechterlein, Keith H; Pela, Marlena; Radant, Allen D; Seidman, Larry J; Sharp, Richard F; Siever, Larry J; Silverman, Jeremy M; Sprock, Joyce; Stone, William S; Sugar, Catherine A; Tsuang, Debby W; Tsuang, Ming T; Braff, David L; Turetsky, Bruce I

2015-04-01

Mismatch negativity (MMN) and P3a are auditory event-related potential (ERP) components that show robust deficits in schizophrenia (SZ) patients and exhibit qualities of endophenotypes, including substantial heritability, test-retest reliability, and trait-like stability. These measures also fulfill criteria for use as cognition and function-linked biomarkers in outcome studies, but have not yet been validated for use in large-scale multi-site clinical studies. This study tested the feasibility of adding MMN and P3a to the ongoing Consortium on the Genetics of Schizophrenia (COGS) study. The extent to which demographic, clinical, cognitive, and functional characteristics contribute to variability in MMN and P3a amplitudes was also examined. Participants (HCS n=824, SZ n=966) underwent testing at 5 geographically distributed COGS laboratories. Valid ERP recordings were obtained from 91% of HCS and 91% of SZ patients. Highly significant MMN (d=0.96) and P3a (d=0.93) amplitude reductions were observed in SZ patients, comparable in magnitude to those observed in single-lab studies with no appreciable differences across laboratories. Demographic characteristics accounted for 26% and 18% of the variance in MMN and P3a amplitudes, respectively. Significant relationships were observed among demographically-adjusted MMN and P3a measures and medication status as well as several clinical, cognitive, and functional characteristics of the SZ patients. This study demonstrates that MMN and P3a ERP biomarkers can be feasibly used in multi-site clinical studies. As with many clinical tests of brain function, demographic factors contribute to MMN and P3a amplitudes and should be carefully considered in future biomarker-informed clinical studies. Published by Elsevier B.V.

The Analysis for Activations in the Brain during Hearing the Amplitude-Modulated Tone by fMRI Measurement

NASA Astrophysics Data System (ADS)

Fukami, Tadanori; Shimada, Takamasa; Akatsuka, Takao; Saito, Yoichi

In audiometry, ABR (Auditory Brainstem Response) is widely used. However, it shows low accuracy in low frequency band. Meanwhile, AMFR (Amplitude-Modulation-Following Response), the response during hearing an amplitude-modulated tone, has high frequency specificity and is brought to attention. As the first step to clinical application of AMFR, we investigated the activated areas in a brain when the subjects hear SAM tone (Sinusoidally Amplitude-Modulated tone) with both ears. We measured following two signals. One is the difference of BOLD (Blood Oxygenation Level Dependent) signal between hearing SAM tone vs. silence, the other is the difference of BOLD signal between hearing SAM tone vs. unmodulated tone. As a result, in the case of SAM vs. silence, the bilaterally auditory cortex (Broadmann Area 41, 42), the biratelally BA 10, left superior frontal gyrus and right superior temporal gyrus were activated (p<0.0037, uncorrected). In the case of SAM vs. unmodulated tone, the bilaterally superior frontal gyrus (BA 6) and precuneus (BA 7), neighboring area including the bilaterally inferior parietal lobule (BA 40), the bilaterally medial frontal gyrus and superior frontal gyrus were activated (p<0.021, uncorrected). Activations of visual perception due to eye-opened state were detected in some parts of activations. As a result, we inferred that modulated tone was recognized in the medial frontal gyrus and inferior parietal lobule was the part related to perception of amplitude-modulation.

Warp-averaging event-related potentials.

PubMed

Wang, K; Begleiter, H; Porjesz, B

2001-10-01

To align the repeated single trials of the event-related potential (ERP) in order to get an improved estimate of the ERP. A new implementation of the dynamic time warping is applied to compute a warp-average of the single trials. The trilinear modeling method is applied to filter the single trials prior to alignment. Alignment is based on normalized signals and their estimated derivatives. These features reduce the misalignment due to aligning the random alpha waves, explaining amplitude differences in latency differences, or the seemingly small amplitudes of some components. Simulations and applications to visually evoked potentials show significant improvement over some commonly used methods. The new implementation of the dynamic time warping can be used to align the major components (P1, N1, P2, N2, P3) of the repeated single trials. The average of the aligned single trials is an improved estimate of the ERP. This could lead to more accurate results in subsequent analysis.

A view on coupled cluster perturbation theory using a bivariational Lagrangian formulation.

PubMed

Kristensen, Kasper; Eriksen, Janus J; Matthews, Devin A; Olsen, Jeppe; Jørgensen, Poul

2016-02-14

We consider two distinct coupled cluster (CC) perturbation series that both expand the difference between the energies of the CCSD (CC with single and double excitations) and CCSDT (CC with single, double, and triple excitations) models in orders of the Møller-Plesset fluctuation potential. We initially introduce the E-CCSD(T-n) series, in which the CCSD amplitude equations are satisfied at the expansion point, and compare it to the recently developed CCSD(T-n) series [J. J. Eriksen et al., J. Chem. Phys. 140, 064108 (2014)], in which not only the CCSD amplitude, but also the CCSD multiplier equations are satisfied at the expansion point. The computational scaling is similar for the two series, and both are term-wise size extensive with a formal convergence towards the CCSDT target energy. However, the two series are different, and the CCSD(T-n) series is found to exhibit a more rapid convergence up through the series, which we trace back to the fact that more information at the expansion point is utilized than for the E-CCSD(T-n) series. The present analysis can be generalized to any perturbation expansion representing the difference between a parent CC model and a higher-level target CC model. In general, we demonstrate that, whenever the parent parameters depend upon the perturbation operator, a perturbation expansion of the CC energy (where only parent amplitudes are used) differs from a perturbation expansion of the CC Lagrangian (where both parent amplitudes and parent multipliers are used). For the latter case, the bivariational Lagrangian formulation becomes more than a convenient mathematical tool, since it facilitates a different and faster convergent perturbation series than the simpler energy-based expansion.

New insights into name category-related effects: is the Age of Acquisition a possible factor?

PubMed

Adorni, Roberta; Proverbio, Alice Mado

2009-07-29

Electrophysiological, hemodynamic and neuropsychological studies have provided evidence of dissociation in the way words belonging to different semantic categories (e.g., animals, tools, actions) are represented in the brain. The aim of the present study was to investigate whether a word's semantic domain may affect the amplitude and latency of ERP components, independently of any other factor. EEGs were recorded from 16 volunteers engaged in a lexical decision task (word/non-word discrimination) involving 100 words (flora and fauna names). This task allowed us to evaluate differences in processing between words belonging to different categories (fauna vs. flora) independently of task demands. All stimuli were balanced in terms of length, frequency of occurrence, familiarity and imageability. Low Resolution Electromagnetic Tomography (LORETA) was performed on ERP difference waves of interest. Our findings showed that the two categories were discriminated as early as 200 ms post-stimulus, with larger responses to flora names over the left occipito-temporal areas, namely BA37 and BA20. Category-related ERP differences were also observed in the amplitudes of the later centro-parietal N400, posterior P300 and anterior LP components. Behavioral responses to words denoting fauna were more accurate than to words denoting flora. Overall, it seems that it was easier to access the lexical properties of fauna, probably because of their biologically relevant status. The results are discussed in the light of the possible role played by different factors.

Cylindrical fast magnetosonic solitary waves in quantum degenerate electron-positron-ion plasma

NASA Astrophysics Data System (ADS)

Abdikian, A.

2018-02-01

The nonlinear properties of fast magnetosonic solitary waves in a quantum degenerate electron-positron (e-p) plasma in the presence of stationary ions for neutralizing the plasma background of bounded cylindrical geometry were studied. By employing the standard reductive perturbation technique and the quantum hydrodynamic model for the e-p fluid, the cylindrical Kadomtsev-Petviashvili (CKP) equation was derived for small, but finite, amplitude waves and was given the solitary wave solution for the parameters relevant to dense astrophysical objects such as white dwarf stars. By a suitable coordinate transformation, the CKP equation can be solved analytically. An analytical solution for magnetosonic solitons and periodic waves is presented. The numerical results reveal that the Bohm potential has a main effect on the periodic and solitary wave structures. By increasing the values of the plasma parameters, the amplitude of the solitary wave will be increased. The present study may be helpful in the understanding of nonlinear electromagnetic soliton waves propagating in both laboratory and astrophysical plasmas, and can help in providing good agreement between theoretical results and laboratory plasma experiments.

Beam normal spin asymmetry for the e p → e Δ ( 1232 ) process

DOE Office of Scientific and Technical Information (OSTI.GOV)

Carlson, Carl E.; Pasquini, Barbara; Pauk, Vladyslav

Here, we calculate the single spin asymmetry for themore » $$e p \\to e \\Delta(1232)$$ process, for an electron beam polarized normal to the scattering plane. Such single spin asymmetries vanish in the one-photon exchange approximation, and are directly proportional to the absorptive part of a two-photon exchange amplitude. As the intermediate state in such two-photon exchange process is on its mass shell, the asymmetry allows one to access for the first time the on-shell $$\\Delta \\to \\Delta$$ as well as $$N^\\ast \\to \\Delta$$ electromagnetic transitions. We present the general formalism to describe the $$e p \\to e \\Delta$$ beam normal spin asymmetry, and provide a numerical estimate of its value using the nucleon, $$\\Delta(1232)$$, $$S_{11}(1535)$$, and $$D_{13}(1520)$$ intermediate states. We compare our results with the first data from the Qweak@JLab experiment and give predictions for the A4@MAMI experiment.« less

Beam normal spin asymmetry for the e p → e Δ ( 1232 ) process

DOE PAGES

Carlson, Carl E.; Pasquini, Barbara; Pauk, Vladyslav; ...

2017-12-26

Here, we calculate the single spin asymmetry for themore » $$e p \\to e \\Delta(1232)$$ process, for an electron beam polarized normal to the scattering plane. Such single spin asymmetries vanish in the one-photon exchange approximation, and are directly proportional to the absorptive part of a two-photon exchange amplitude. As the intermediate state in such two-photon exchange process is on its mass shell, the asymmetry allows one to access for the first time the on-shell $$\\Delta \\to \\Delta$$ as well as $$N^\\ast \\to \\Delta$$ electromagnetic transitions. We present the general formalism to describe the $$e p \\to e \\Delta$$ beam normal spin asymmetry, and provide a numerical estimate of its value using the nucleon, $$\\Delta(1232)$$, $$S_{11}(1535)$$, and $$D_{13}(1520)$$ intermediate states. We compare our results with the first data from the Qweak@JLab experiment and give predictions for the A4@MAMI experiment.« less

Correction of ultrasonic wave aberration with a time delay and amplitude filter.

PubMed

Måsøy, Svein-Erik; Johansen, Tonni F; Angelsen, Bjørn

2003-04-01

Two-dimensional simulations with propagation through two different heterogeneous human body wall models have been performed to analyze different correction filters for ultrasonic wave aberration due to forward wave propagation. The different models each produce most of the characteristic aberration effects such as phase aberration, relatively strong amplitude aberration, and waveform deformation. Simulations of wave propagation from a point source in the focus (60 mm) of a 20 mm transducer through the body wall models were performed. Center frequency of the pulse was 2.5 MHz. Corrections of the aberrations introduced by the two body wall models were evaluated with reference to the corrections obtained with the optimal filter: a generalized frequency-dependent phase and amplitude correction filter [Angelsen, Ultrasonic Imaging (Emantec, Norway, 2000), Vol. II]. Two correction filters were applied, a time delay filter, and a time delay and amplitude filter. Results showed that correction with a time delay filter produced substantial reduction of the aberration in both cases. A time delay and amplitude correction filter performed even better in both cases, and gave correction close to the ideal situation (no aberration). The results also indicated that the effect of the correction was very sensitive to the accuracy of the arrival time fluctuations estimate, i.e., the time delay correction filter.

Relationship between early and late stages of information processing: an event-related potential study

PubMed Central

Portella, Claudio; Machado, Sergio; Arias-Carrión, Oscar; Sack, Alexander T.; Silva, Julio Guilherme; Orsini, Marco; Leite, Marco Antonio Araujo; Silva, Adriana Cardoso; Nardi, Antonio E.; Cagy, Mauricio; Piedade, Roberto; Ribeiro, Pedro

2012-01-01

The brain is capable of elaborating and executing different stages of information processing. However, exactly how these stages are processed in the brain remains largely unknown. This study aimed to analyze the possible correlation between early and late stages of information processing by assessing the latency to, and amplitude of, early and late event-related potential (ERP) components, including P200, N200, premotor potential (PMP) and P300, in healthy participants in the context of a visual oddball paradigm. We found a moderate positive correlation among the latency of P200 (electrode O2), N200 (electrode O2), PMP (electrode C3), P300 (electrode PZ) and the reaction time (RT). In addition, moderate negative correlation between the amplitude of P200 and the latencies of N200 (electrode O2), PMP (electrode C3), P300 (electrode PZ) was found. Therefore, we propose that if the secondary processing of visual input (P200 latency) occurs faster, the following will also happen sooner: discrimination and classification process of this input (N200 latency), motor response processing (PMP latency), reorganization of attention and working memory update (P300 latency), and RT. N200, PMP, and P300 latencies are also anticipated when higher activation level of occipital areas involved in the secondary processing of visual input rise (P200 amplitude). PMID:23355929

Protective effect of high concentration of BN52021 on retinal contusion in cat eyes.

PubMed

Huang, Jin-Feng; Zhao, Hai-Peng; Yang, Yan-Feng; Huang, Hui-Min; Yao, Yi; Wang, Zhi-Jun

2015-05-09

Blunt injuries/contusion on eyes might cause retina blunt trauma. This study is to evaluate the protective function of BN52021 against retinal trauma. A total of 70 cats, 6 months old, were divided into six groups: Group A to E (n = 12) and normal control (N) group (n = 10). The right eyes in Group A to E were contused. All experiments were performed under general anesthetization. Retrobulbar injections of medication in right eyes were performed. Cats were administrated with 0.5 mL of normal saline (NS), dimethyl sulphoxide, 0.2 g/L BN52021, 1 g/L BN52021 and 5 g/L BN52021, respectively. Cats in Group N were administrated with 0.5 mL of NS. Intraocular pressure (IOP), flash electroretinogram (ERG), and retinal nerve fiber layer (RNFL) thickness were measured. Hematoxylin and eosin (HE) staining and transmission electron microscope (TEM) were detected. No significant difference was observed in IOP levels among groups. Comparing with cats in Group N, those in Group A to E showed significant lower amplitudes of rod a- and b-waves (P < 0.05). Amplitudes of rod a- and b-waves were increased by administration of high concentration of BN52021 (≥ 1 g/L). Moreover, high concentration of BN52021 decreased the RNFL thickness increased by contusion. Axons in RNFL in Group E arranged neatly at 7 days after modeling. The degenerated axons caused by contusion were repaired by BN52021. The administration of high concentration of (≥ 1 g/L) BN52021 could partially repair retinal function in contused cat eyes.

A New Network-Based Approach for the Earthquake Early Warning

NASA Astrophysics Data System (ADS)

Alessandro, C.; Zollo, A.; Colombelli, S.; Elia, L.

2017-12-01

Here we propose a new method which allows for issuing an early warning based upon the real-time mapping of the Potential Damage Zone (PDZ), e.g. the epicentral area where the peak ground velocity is expected to exceed the damaging or strong shaking levels with no assumption about the earthquake rupture extent and spatial variability of ground motion. The system includes the techniques for a refined estimation of the main source parameters (earthquake location and magnitude) and for an accurate prediction of the expected ground shaking level. The system processes the 3-component, real-time ground acceleration and velocity data streams at each station. For stations providing high quality data, the characteristic P-wave period (τc) and the P-wave displacement, velocity and acceleration amplitudes (Pd, Pv and Pa) are jointly measured on a progressively expanded P-wave time window. The evolutionary estimate of these parameters at stations around the source allow to predict the geometry and extent of PDZ, but also of the lower shaking intensity regions at larger epicentral distances. This is done by correlating the measured P-wave amplitude with the Peak Ground Velocity (PGV) and Instrumental Intensity (IMM) and by interpolating the measured and predicted P-wave amplitude at a dense spatial grid, including the nodes of the accelerometer/velocimeter array deployed in the earthquake source area. Depending of the network density and spatial source coverage, this method naturally accounts for effects related to the earthquake rupture extent (e.g. source directivity) and spatial variability of strong ground motion related to crustal wave propagation and site amplification. We have tested this system by a retrospective analysis of three earthquakes: 2016 Italy 6.5 Mw, 2008 Iwate-Miyagi 6.9 Mw and 2011 Tohoku 9.0 Mw. Source parameters characterization are stable and reliable, also the intensity map shows extended source effects consistent with kinematic fracture models of evets.

Neural Correlates of the Binaural Masking Level Difference in Human Frequency-Following Responses.

PubMed

Clinard, Christopher G; Hodgson, Sarah L; Scherer, Mary Ellen

2017-04-01

The binaural masking level difference (BMLD) is an auditory phenomenon where binaural tone-in-noise detection is improved when the phase of either signal or noise is inverted in one of the ears (S π N o or S o N π , respectively), relative to detection when signal and noise are in identical phase at each ear (S o N o ). Processing related to BMLDs and interaural time differences has been confirmed in the auditory brainstem of non-human mammals; in the human auditory brainstem, phase-locked neural responses elicited by BMLD stimuli have not been systematically examined across signal-to-noise ratio. Behavioral and physiological testing was performed in three binaural stimulus conditions: S o N o , S π N o , and S o N π . BMLDs at 500 Hz were obtained from 14 young, normal-hearing adults (ages 21-26). Physiological BMLDs used the frequency-following response (FFR), a scalp-recorded auditory evoked potential dependent on sustained phase-locked neural activity; FFR tone-in-noise detection thresholds were used to calculate physiological BMLDs. FFR BMLDs were significantly smaller (poorer) than behavioral BMLDs, and FFR BMLDs did not reflect a physiological release from masking, on average. Raw FFR amplitude showed substantial reductions in the S π N o condition relative to S o N o and S o N π conditions, consistent with negative effects of phase summation from left and right ear FFRs. FFR amplitude differences between stimulus conditions (e.g., S o N o amplitude-S π N o amplitude) were significantly predictive of behavioral S π N o BMLDs; individuals with larger amplitude differences had larger (better) behavioral B MLDs and individuals with smaller amplitude differences had smaller (poorer) behavioral B MLDs. These data indicate a role for sustained phase-locked neural activity in BMLDs of humans and are the first to show predictive relationships between behavioral BMLDs and human brainstem responses.

Role of 20th tropical precipitation on ENSO amplitude changes due to greenhouse warming in CMIP5

NASA Astrophysics Data System (ADS)

Ham, Yoo-Geun; Kug, Jong-Seong

2016-04-01

This study examines the relationship between the intermodel diversities of the present-climate climatology and those of ENSO amplitude change under global warming in the Coupled Model Intercomparison Project phase 5 (CMIP5) models. The models with increased ENSO amplitude under greenhouse warming (i.e., 'ENSO-amplified models') tend to simulate a 20th century stronger climatological ITCZ and SPCZ over the central-eastern Pacific that are located further away from the equator during boreal spring. Moisture budget analysis indicates that those climatological differences lead to stronger positive climatological precipitation change over the off-equatorial central-eastern Pacific under greenhouse warming. The stronger positive climatological precipitation change enhances the air-sea coupling strength over the central-eastern Pacific, which leads to increase the ENSO amplitude.

Conflict-Specific Aging Effects Mainly Manifest in Early Information Processing Stages-An ERP Study with Different Conflict Types.

PubMed

Korsch, Margarethe; Frühholz, Sascha; Herrmann, Manfred

2016-01-01

Aging is usually accompanied by alterations of cognitive control functions such as conflict processing. Recent research suggests that aging effects on cognitive control seem to vary with degree and source of conflict, and conflict specific aging effects on performance measures as well as neural activation patterns have been shown. However, there is sparse information whether and how aging affects different stages of conflict processing as indicated by event related potentials (ERPs) such as the P2, N2 and P3 components. In the present study, 19 young and 23 elderly adults performed a combined Flanker conflict and stimulus-response-conflict (SRC) task. Analysis of the reaction times (RTs) revealed an increased SRC related conflict effect in elderly. ERP analysis furthermore demonstrated an age-related increase of the P2 amplitude in response to the SRC task. In addition, elderly adults exhibited an increased P3 amplitude modulation induced by incongruent SRC and Flanker conflict trials.

Contingent negative variation before and after hemodialysis among patients with end-stage renal disease.

PubMed

Bae, Jong Seok; Park, Sung Sik

2008-04-15

To investigate changes in contingent negative variation (CNV) induced by uremia and to study the effects of hemodialysis. Fifteen right-handed healthy subjects and 12 patients with end-stage renal disease (ESRD) were studied. CNV was recorded from the Fz, Cz and Pz (using the International 10-20 System) referenced to linked ear lobes, using an S1 (click)-S2 (flashes)-key press paradigm. The amplitude of initial CNV (iCNV) was calculated as the average amplitude at 550-750 ms after S1. The amplitude of late CNV (lCNV) was the mean amplitude of the last 200 ms before S2. Testing was repeated for the patient group at pre- and post-hemodialysis observations. Neuropsychological measurements, a trail making test (TMT) and mini-mental state examination (MMSE), were conducted at each time. The mean amplitudes of iCNV and lCNV at the vertex (Cz) were both significantly lower in the patient group than in the control group (P<0.05). TMT were also significantly different between patient and control groups (P<0.05)), however MMSE showed no significant difference. There were no significant correlations between the values of neuropsychological tests and the parameters of CNV. Both iCNV and lCNV were not significantly different between the pre- and post-dialysis tests. CNV negativity in patients with ESRD reflects diffuse nonlocalizing neurological symptoms of uremia rather than a selective involvement of the frontal lobes. It is likely to reflect dysfunction in the frontal-subcortical circuit. In addition, hemodialysis seemed to have no significant effect on executive brain function in these patients with ESRD.

SU-E-J-115: Correlation of Displacement Vector Fields Calculated by Deformable Image Registration Algorithms with Motion Parameters of CT Images with Well-Defined Targets and Controlled-Motion

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jaskowiak, J; Ahmad, S; Ali, I

Purpose: To investigate correlation of displacement vector fields (DVF) calculated by deformable image registration algorithms with motion parameters in helical axial and cone-beam CT images with motion artifacts. Methods: A mobile thorax phantom with well-known targets with different sizes that were made from water-equivalent material and inserted in foam to simulate lung lesions. The thorax phantom was imaged with helical, axial and cone-beam CT. The phantom was moved with a cyclic motion with different motion amplitudes and frequencies along the superior-inferior direction. Different deformable image registration algorithms including demons, fast demons, Horn-Shunck and iterative-optical-flow from the DIRART software were usedmore » to deform CT images for the phantom with different motion patterns. The CT images of the mobile phantom were deformed to CT images of the stationary phantom. Results: The values of displacement vectors calculated by deformable image registration algorithm correlated strongly with motion amplitude where large displacement vectors were calculated for CT images with large motion amplitudes. For example, the maximal displacement vectors were nearly equal to the motion amplitudes (5mm, 10mm or 20mm) at interfaces between the mobile targets lung tissue, while the minimal displacement vectors were nearly equal to negative the motion amplitudes. The maximal and minimal displacement vectors matched with edges of the blurred targets along the Z-axis (motion-direction), while DVF’s were small in the other directions. This indicates that the blurred edges by phantom motion were shifted largely to match with the actual target edge. These shifts were nearly equal to the motion amplitude. Conclusions: The DVF from deformable-image registration algorithms correlated well with motion amplitude of well-defined mobile targets. This can be used to extract motion parameters such as amplitude. However, as motion amplitudes increased, image artifacts increased significantly and that limited image quality and poor correlation between the motion amplitude and DVF was obtained.« less

Habituation deficit of auditory N100m in patients with fibromyalgia.

PubMed

Choi, W; Lim, M; Kim, J S; Chung, C K

2016-11-01

Habituation refers to the brain's inhibitory mechanism against sensory overload and its brain correlate has been investigated in the form of a well-defined event-related potential, N100 (N1). Fibromyalgia is an extensively described chronic pain syndrome with concurrent manifestations of reduced tolerance and enhanced sensation of painful and non-painful stimulation, suggesting an association with central amplification of all sensory domains. Among diverse sensory modalities, we utilized repetitive auditory stimulation to explore the anomalous sensory information processing in fibromyalgia as evidenced by N1 habituation. Auditory N1 was assessed in 19 fibromyalgia patients and age-, education- and gender-matched 21 healthy control subjects under the duration-deviant passive oddball paradigm and magnetoencephalography recording. The brain signal of the first standard stimulus (following each deviant) and last standard stimulus (preceding each deviant) were analysed to identify N1 responses. N1 amplitude difference and adjusted amplitude ratio were computed as habituation indices. Fibromyalgia patients showed lower N1 amplitude difference (left hemisphere: p = 0.004; right hemisphere: p = 0.034) and adjusted N1 amplitude ratio (left hemisphere: p = 0.001; right hemisphere: p = 0.052) than healthy control subjects, indicating deficient auditory habituation. Further, augmented N1 amplitude pattern (p = 0.029) during the stimulus repetition was observed in fibromyalgia patients. Fibromyalgia patients failed to demonstrate auditory N1 habituation to repetitively presenting stimuli, which indicates their compromised early auditory information processing. Our findings provide neurophysiological evidence of inhibitory failure and cortical augmentation in fibromyalgia. WHAT'S ALREADY KNOWN ABOUT THIS TOPIC?: Fibromyalgia has been associated with altered filtering of irrelevant somatosensory input. However, whether this abnormality can extend to the auditory sensory system remains controversial. N!00, an event-related potential, has been widely utilized to assess the brain's habituation capacity against sensory overload. WHAT DOES THIS STUDY ADD?: Fibromyalgia patients showed defect in N100 habituation to repetitive auditory stimuli, indicating compromised early auditory functioning. This study identified deficient inhibitory control over irrelevant auditory stimuli in fibromyalgia. © 2016 European Pain Federation - EFIC®.

High-Frequency Normal Mode Propagation in Aluminum Cylinders

USGS Publications Warehouse

Lee, Myung W.; Waite, William F.

2009-01-01

Acoustic measurements made using compressional-wave (P-wave) and shear-wave (S-wave) transducers in aluminum cylinders reveal waveform features with high amplitudes and with velocities that depend on the feature's dominant frequency. In a given waveform, high-frequency features generally arrive earlier than low-frequency features, typical for normal mode propagation. To analyze these waveforms, the elastic equation is solved in a cylindrical coordinate system for the high-frequency case in which the acoustic wavelength is small compared to the cylinder geometry, and the surrounding medium is air. Dispersive P- and S-wave normal mode propagations are predicted to exist, but owing to complex interference patterns inside a cylinder, the phase and group velocities are not smooth functions of frequency. To assess the normal mode group velocities and relative amplitudes, approximate dispersion relations are derived using Bessel functions. The utility of the normal mode theory and approximations from a theoretical and experimental standpoint are demonstrated by showing how the sequence of P- and S-wave normal mode arrivals can vary between samples of different size, and how fundamental normal modes can be mistaken for the faster, but significantly smaller amplitude, P- and S-body waves from which P- and S-wave speeds are calculated.

The roles of selective attention and desensitization in the association between video gameplay and aggression: An ERP investigation.

PubMed

Jabr, Mejdy M; Denke, Greg; Rawls, Eric; Lamm, Connie

2018-04-01

A number of studies have indicated that violent video gameplay is associated with higher levels of aggression and that desensitization and selective attention to violent content may contribute to this association. Utilizing an emotionally-charged rapid serial visual presentation (RSVP) task, the current study used two event-related potentials (ERPs) - the N1 and P3 - that have been associated with selective attention and desensitization as neurocognitive mechanisms potentially underlying the connection between gameplay and higher levels of aggression. Results indicated that video game players and non-players differed in N1 and P3 activation when engaged with emotionally-charged imagery. Additionally, P3 amplitudes moderated the association between video gameplay and aggression, indicating that players who display small P3 amplitudes also showed heightened levels of aggression. Follow-up moderational analyses revealed that individuals who play games for many hours and show more negative N1 amplitudes show smaller P3 activation. Together, our results suggest that selective attention to violent content and desensitization both play key roles in the association between video gameplay and aggression. Copyright © 2018 Elsevier Ltd. All rights reserved.

Human Evoked Cortical Activity to Silent Gaps in Noise: Effects of Age, Attention, and Cortical Processing Speed

PubMed Central

Harris, Kelly C.; Wilson, Sara; Eckert, Mark A.; Dubno, Judy R.

2011-01-01

Objectives The goal of this study was to examine the degree to which age-related differences in early or automatic levels of auditory processing and attention-related processes explain age-related differences in auditory temporal processing. We hypothesized that age-related differences in attention and cognition compound age-related differences at automatic levels of processing, contributing to the robust age effects observed during challenging listening tasks. Design We examined age-related and individual differences in cortical event-related potential (ERP) amplitudes and latencies, processing speed, and gap detection from twenty-five younger and twenty-five older adults with normal hearing. ERPs were elicited by brief silent periods (gaps) in an otherwise continuous broadband noise and were measured under two listening conditions, passive and active. During passive listening, participants ignored the stimulus and read quietly. During active listening, participants button pressed each time they detected a gap. Gap detection (percent detected) was calculated for each gap duration during active listening (3, 6, 9, 12 and 15 ms). Processing speed was assessed using the Purdue Pegboard test and the Connections Test. Repeated measures ANOVAs assessed effects of age on gap detection, processing speed, and ERP amplitudes and latencies. An “attention modulation” construct was created using linear regression to examine the effects of attention while controlling for age-related differences in auditory processing. Pearson correlation analyses assessed the extent to which attention modulation, ERPs, and processing speed predicted behavioral gap detection. Results: Older adults had significantly poorer gap detection and slower processing speed than younger adults. Even after adjusting for poorer gap detection, the neurophysiological response to gap onset was atypical in older adults with reduced P2 amplitudes and virtually absent N2 responses. Moreover, individual differences in attention modulation of P2 response latencies and N2 amplitudes predicted gap detection and processing speed in older adults. That is, older adults with P2 latencies that decreased and N2 amplitudes that increased with active listening had faster processing speed and better gap detection than those older adults whose P2 latencies increased and N2 amplitudes decreased with attention Conclusions Results from the current study are broadly consistent with previous findings that older adults exhibit significantly poorer gap detection than younger adults in challenging tasks. Even after adjusting for poorer gap detection, older and younger adults showed robust differences in their electrophysiological responses to sound offset. Furthermore, the degree to which attention modulated the ERP was associated with individual variation in measures of processing speed and gap detection. Taken together, these results suggests an age-related deficit in early or automatic levels of auditory temporal processing and that some older adults may be less able to compensate for declines in processing by attending to the stimulus. These results extend our previous findings and support the hypothesis that age-related differences in cognitive or attention-related processing, including processing speed, contribute to an age-related decrease in gap detection. PMID:22374321

Event-related potentials of self-face recognition in children with pervasive developmental disorders.

PubMed

Gunji, Atsuko; Inagaki, Masumi; Inoue, Yuki; Takeshima, Yasuyuki; Kaga, Makiko

2009-02-01

Patients with pervasive developmental disorders (PDD) often have difficulty reading facial expressions and deciphering their implied meaning. We focused on semantic encoding related to face cognition to investigate event-related potentials (ERPs) to the subject's own face and familiar faces in children with and without PDD. Eight children with PDD (seven boys and one girl; aged 10.8+/-2.9 years; one left-handed) and nine age-matched typically developing children (four boys and five girls; aged 11.3+/-2.3 years; one left-handed) participated in this study. The stimuli consisted of three face images (self, familiar, and unfamiliar faces), one scrambled face image, and one object image (e.g., cup) with gray scale. We confirmed three major components: N170 and early posterior negativity (EPN) in the occipito-temporal regions (T5 and T6) and P300 in the parietal region (Pz). An enhanced N170 was observed as a face-specific response in all subjects. However, semantic encoding of each face might be unrelated to N170 because the amplitude and latency were not significantly different among the face conditions. On the other hand, an additional component after N170, EPN which was calculated in each subtracted waveform (self vs. familiar and familiar vs. unfamiliar), indicated self-awareness and familiarity with respect to face cognition in the control adults and children. Furthermore, the P300 amplitude in the control adults was significantly greater in the self-face condition than in the familiar-face condition. However, no significant differences in the EPN and P300 components were observed among the self-, familiar-, and unfamiliar-face conditions in the PDD children. The results suggest a deficit of semantic encoding of faces in children with PDD, which may be implicated in their delay in social communication.

Reynolds number effects on the single-mode Richtmyer-Meshkov instability.

PubMed

Walchli, B; Thornber, B

2017-01-01

The Reynolds number effects on the nonlinear growth rates of the Richtmyer-Meshkov instability are investigated using two-dimensional numerical simulations. A decrease in Reynolds number gives an increased time to reach nonlinear saturation, with Reynolds number effects only significant in the range Re<256. Within this range there is a sharp change in instability properties. The bubble and spike amplitudes move towards equal size at lower Reynolds numbers and the bubble velocities decay faster than predicted by Sohn's model [S.-I. Sohn, Phys. Rev. E 80, 055302 (2009)PLEEE81539-375510.1103/PhysRevE.80.055302]. Predicted amplitudes show reasonable agreement with the existing theory of Carles and Popinet [P. Carles and S. Popinet, Phys. Fluids Lett. 13, 1833 (2001)10.1063/1.1377863; Eur. J. Mech. B 21, 511 (2002)EJBFEV0997-754610.1016/S0997-7546(02)01199-8] and Mikaelian [K. O. Mikaelian, Phys. Rev. E 47, 375 (1993)1063-651X10.1103/PhysRevE.47.375; K. O. Mikaelian, Phys. Rev. E 87, 031003 (2013)PLEEE81539-375510.1103/PhysRevE.87.031003], with the former being the closest match to the current computations.

Analysis of heart rate and oxygen uptake kinetics studied by two different pseudo-random binary sequence work rate amplitudes.

PubMed

Drescher, U; Koschate, J; Schiffer, T; Schneider, S; Hoffmann, U

2017-06-01

The aim of the study was to compare the kinetics responses of heart rate (HR), pulmonary (V˙O 2 pulm) and predicted muscular (V˙O 2 musc) oxygen uptake between two different pseudo-random binary sequence (PRBS) work rate (WR) amplitudes both below anaerobic threshold. Eight healthy individuals performed two PRBS WR protocols implying changes between 30W and 80W and between 30W and 110W. HR and V˙O 2 pulm were measured beat-to-beat and breath-by-breath, respectively. V˙O 2 musc was estimated applying the approach of Hoffmann et al. (Eur J Appl Physiol 113: 1745-1754, 2013) considering a circulatory model for venous return and cross-correlation functions (CCF) for the kinetics analysis. HR and V˙O 2 musc kinetics seem to be independent of WR intensity (p>0.05). V˙O 2 pulm kinetics show prominent differences in the lag of the CCF maximum (39±9s; 31±4s; p<0.05). A mean difference of 14W between the PRBS WR amplitudes impacts venous return significantly, while HR and V˙O 2 musc kinetics remain unchanged. Copyright © 2017 Elsevier B.V. All rights reserved.

[Visual perception of Kanji characters and complicated figures. II. Visual P300 event-related potentials in patients with mental retardation].

PubMed

Sata, Yoshimi; Inagaki, Masumi; Shirane, Seiko; Kaga, Makiko

2002-11-01

In order to objectively evaluate visual perception of patients with mental retardation (MR), the P300 event-related potentials (ERPs) for visual oddball tasks were recorded in 26 patients and 13 age-matched healthy volunteers. The latency and amplitude of visual P300 in response to the Japanese ideogram stimuli (a pair of familiar Kanji characters or unfamiliar Kanji characters) and a pair of meaningless complicated figures were measured. In almost all MR patients visual P300 was observed, however, the peak latency was significantly prolonged compared to control subjects. There was no significant difference of P300 latency among the three tasks. The distribution pattern of P300 in MR patients was different from that in the controls and the amplitudes in the frontal region was larger in MR patients. The latency decreased with age even in both groups. The developmental change of P300 latency corresponded to developmental age rather than the chronological age. These findings suggest that MR patients have impairment in processing of visual perception. Assessment of P300 latencies to the visual stimuli may be useful as an objective indicator of mental deficit.

Nontarget-to-nontarget interval determines the nontarget P300 in an auditory equiprobable Go/NoGo task.

PubMed

Steiner, Genevieve Z; Barry, Robert J; Gonsalvez, Craig J

2014-06-01

Increases in the target-to-target interval (TTI) systematically enhance the amplitude of the target P300 ERP component. Research examining changes in nontarget P300 related to nontarget-to-nontarget interval (NNI) or sequential probability manipulations has produced inconsistent results, with some studies reporting no enhancement in nontarget P300 and others finding response profiles analogous to TTI effects. Our aim was to clarify these differences. All participants completed a specially designed auditory equiprobable Go/NoGo task with manipulations of TTI and NNI while their EEG activity was recorded. P300 amplitudes were extracted using temporal PCA with Varimax rotation. P3b to targets and nontargets increased systematically as respective TTIs/NNIs increased, but this change did not differ between stimulus types. The Slow Wave did not show any effect of interval, but was more positive to targets than nontargets when interval was collapsed. P3b findings show that matching-stimulus interval effects are not restricted to targets, but discrepancies relative to previous research suggest that NNI effects in P3b may depend on additional processing of nontarget stimuli. Copyright © 2014 Elsevier B.V. All rights reserved.

Extensive computation of allowed and forbidden transition probabilities in the potassium isoelectronic sequence

NASA Astrophysics Data System (ADS)

Dixit, Gopal; Deshmukh, Pranawa C.; Manson, Steven T.; Majumder, Sonjoy

2007-06-01

Our primary aim in this work is to present both allowed and forbidden transition amplitudes and corresponding wavelengths and oscillator strengths for a few ions in the 19-electron potassium isoelectronic sequence. All of these ions have the configuration [Ar] 3^2D3/2 as their ground state, except in the case of K and Ca^+, where it is [Ar] 4^2S1/2.This difference in ground state configuration arises due to strong contributions of correlation effects in the energy levels of these systems [1]. Allowed and forbidden transitions in these systems are of great importance in astrophysics [2] and in laboratory plasma research [3]. We apply in the present work the relativistic coupled-cluster (RCC) theory [4] to evaluate the energy levels and wave functions of these systems and study amplitudes for electric and magnetic dipole transition amplitudes and also the electric quadrupole transition amplitudes. The contributions of various electron correlation effects to the transition amplitudes are estimated in some detail using the RCC theory. [1] Gopal Dixit et al., Astrophys. J (submitted); arXiv.org: physics/0702066. [2] C. R. Cowley and G. M. Wahlgern, Astronomy & Astrophysics, 447, 681 (2002). [3] J. E. Vernazza, E. M. Reeves, Astrophys. J. Suppl. 37, 485 (1978) [4] I. Lindgren, Physics Scripta, 36, 591 (1987).

The error-related negativity (ERN) is an electrophysiological marker of motor impulsiveness on the Barratt Impulsiveness Scale (BIS-11) during adolescence.

PubMed

Taylor, Jasmine B; Visser, Troy A W; Fueggle, Simone N; Bellgrove, Mark A; Fox, Allison M

2018-04-01

Previous studies have postulated that the error-related negativity (ERN) may reflect individual differences in impulsivity; however, none have used a longitudinal framework or evaluated impulsivity as a multidimensional construct. The current study evaluated whether ERN amplitude, measured in childhood and adolescence, is predictive of impulsiveness during adolescence. Seventy-five children participated in this study, initially at ages 7-9 years and again at 12-18 years. The interval between testing sessions ranged from 5 to 9 years. The ERN was extracted in response to behavioural errors produced during a modified visual flanker task at both time points (i.e. childhood and adolescence). Participants also completed the Barratt Impulsiveness Scale - a measure that considers impulsiveness to comprise three core sub-traits - during adolescence. At adolescence, the ERN amplitude was significantly larger than during childhood. Additionally, ERN amplitude during adolescence significantly predicted motor impulsiveness at that time point, after controlling for age, gender, and the number of trials included in the ERN. In contrast, ERN amplitude during childhood did not uniquely predict impulsiveness during adolescence. These findings provide preliminary evidence that ERN amplitude is an electrophysiological marker of self-reported motor impulsiveness (i.e. acting without thinking) during adolescence. Copyright © 2018 The Authors. Published by Elsevier Ltd.. All rights reserved.

[Changes in P-wave, T-wave, and ST segment amplitude in 12 lead electrocardiogram in children with breath holding spell].

PubMed

Zhang, Wenhua; Wang, Cheng; Zou, Runmei; Liu, Liping; Wu, Lijia; Luo, Xuemei; Li, Fang; Liao, Donglei; Cai, Hong

2016-06-28

To explore the change of the amplitude of P wave, T wave and ST segment of 12 lead electrocardiogram (ECG) in children with breath holding spell.
 A total of 29 children (24 males and 5 females) with breath holding spell in Second Xiangya Hospital, Central South University were enrolled for this study from October, 2009 to September, 2015. Their ages ranged from 3 months to 6 years, with an average of 1.82±1.27 years old. The control group consisted of 30 age-matched and gender-matched healthy children. All subjects were underwent electrocardiography by the SR-1000A comprehensive automatic electrocardiograph analyzer, and the changes of the ECG parameters were compared between the two groups.
 Compared with the control group, the amplitude of P-wave of V5 lead was decreased [(44.10±23.98) vs (58.30±21.19) μV, P<0.05], the amplitude of T-wave of V6 lead was increased [(423.80±122.6) vs (350.00±105.73) μV, P<0.05], the amplitude of ST segment of II lead was increased [(84.80±39.97) vs (57.30±38.77) μV, P<0.05], the amplitude of ST segment of aVR lead was increased [(-77.60±37.41) vs (-51.00±33.46) μV, P<0.05], the amplitude of ST segment of aVL lead was increased [(35.20±28.24) vs (17.70±33.90) μV, P<0.05], the amplitude of ST segment of V5 lead was increased [(111.00±59.36) vs (69.00±36.33) μV, P<0.05], the amplitude of ST segment of V6 lead was increased [(79.30±45.51) vs (51.30±33.19) μV, P<0.05]. 
 The children with breath holding spell have autonomic nerve dysfunction. The amplitude of ST segment changes is sensitive.

Real-time processing in picture naming in adults who stutter: ERP evidence

PubMed Central

Maxfield, Nathan D.; Morris, Kalie; Frisch, Stefan A.; Morphew, Kathryn; Constantine, Joseph L.

2014-01-01

Objective The aim was to compare real-time language/cognitive processing in picture naming in adults who stutter (AWS) versus typically-fluent adults (TFA). Methods Participants named pictures preceded by masked prime words. Primes and target picture labels were Identical or mismatched. Priming effects on naming and picture-elicited ERP activity were analyzed. Vocabulary knowledge correlations with these measures were assessed. Results Priming improved naming RTs and accuracy in both groups. RTs were longer for AWS, and correlated positively with receptive vocabulary in TFA. Electrophysiologically, posterior-P1 amplitude negatively correlated with expressive vocabulary in TFA versus receptive vocabulary in AWS. Frontal/temporal-P1 amplitude correlated positively with expressive vocabulary in AWS. Identity priming enhanced frontal/posterior-N2 amplitude in both groups, and attenuated P280 amplitude in AWS. N400 priming was topographically-restricted in AWS. Conclusions Results suggest that conceptual knowledge was perceptually-grounded in expressive vocabulary in TFA versus receptive vocabulary in AWS. Poorer expressive vocabulary in AWS was potentially associated with greater suppression of irrelevant conceptual information. Priming enhanced N2-indexed cognitive control and visual attention in both groups. P280-indexed focal attention attenuated with priming in AWS only. Topographically-restricted N400 priming suggests that lemma/word form connections were weaker in AWS. Significance Real-time language/cognitive processing in picture naming operates differently in AWS. PMID:24910149

Bilateral preictal signature of phase-amplitude coupling in canine epilepsy.

PubMed

Gagliano, Laura; Bou Assi, Elie; Nguyen, Dang K; Rihana, Sandy; Sawan, Mohamad

2018-01-01

Seizure forecasting would improve the quality of life of patients with refractory epilepsy. Although early findings were optimistic, no single feature has been found capable of individually characterizing brain dynamics during transition to seizure. Cross-frequency phase amplitude coupling has been recently proposed as a precursor of seizure activity. This work evaluates the existence of a statistically significant difference in mean phase amplitude coupling distribution between the preictal and interictal states of seizures in dogs with bilaterally implanted intracranial electrodes. Results show a statistically significant change (p<0.05) of phase amplitude coupling during the preictal phase. This change is correlated with the position of implanted electrodes and is more significant within high-gamma frequency bands. These findings highlight the potential benefit of bilateral iEEG analysis and the feasibility of seizure forecasting based on slow modulation of high frequency amplitude. Copyright © 2017 Elsevier B.V. All rights reserved.

Tree-level disk amplitude of three closed strings

NASA Astrophysics Data System (ADS)

Mousavi, Sepideh; Velni, Komeil Babaei

2018-05-01

It has been shown that the disk-level S-matrix elements of one Ramond-Ramond (RR) and two Neveu-Schwarz-Neveu-Schwarz (NSNS) states could be found by applying the Ward identity associated with the string duality and the gauge symmetry on a given component of the S matrix. These amplitudes have appeared as the components of six different T-dual multiplets. It is predicted in the literature that there are some nonzero disk-level scattering amplitudes, such as one RR (p -1 ) form with zero transverse index and two N S N S states, could not be captured by the T-dual Ward identity. We explicitly find this amplitude in terms of a minimal context of the integral functions by the insertion of one closed string RR vertex operator and two NSNS vertex operators. From the amplitude invariance under the Ward identity associated with the NSNS gauge transformations and T-duality, we also find some integral identities.

Transmitter release modulation in nerve terminals of rat neocortical pyramidal cells by intracellular calcium buffers

PubMed Central

Ohana, Ora; Sakmann, Bert

1998-01-01

Dual whole-cell voltage recordings were made from synaptically connected layer 5 (L5) pyramidal neurones in slices of the young (P14-P16) rat neocortex. The Ca2+ buffers BAPTA or EGTA were loaded into the presynaptic neurone via the pipette recording from the presynaptic neurone to examine their effect on the mean and the coefficient of variation (c.v.) of single fibre EPSP amplitudes, referred to as unitary EPSPs. The fast Ca2+ buffer BAPTA reduced unitary EPSP amplitudes in a concentration dependent way. With 0.1 mm BAPTA in the pipette, the mean EPSP amplitude was reduced by 14 ± 2.8% (mean ±s.e.m., n = 7) compared with control pipette solution, whereas with 1.5 mm BAPTA, the mean EPSP amplitude was reduced by 72 ± 1.5% (n = 5). The concentration of BAPTA that reduced mean EPSP amplitudes to one-half of control was close to 0.7 mm. Saturation of BAPTA during evoked release was tested by comparing the effect of loading the presynaptic neurone with 0.1 mm BAPTA at 2 and 1 mm[Ca2+]o. Reducing [Ca2+]o from 2 to 1 mm, thereby reducing Ca2+ influx into the terminals, decreased the mean EPSP amplitude by 60 ± 2.2% with control pipette solution and by 62 ± 1.9% after loading with 0.1 mm BAPTA (n = 7). The slow Ca2+ buffer EGTA at 1 mm reduced mean EPSP amplitudes by 15 ± 2.5% (n = 5). With 10 mm EGTA mean EPSP amplitudes were reduced by 56 ± 2.3% (n = 4). With both Ca2+ buffers, the reduction in mean EPSP amplitudes was associated with an increase in the c.v. of peak EPSP amplitudes, consistent with a reduction of the transmitter release probability as the major mechanism underlying the reduction of the EPSP amplitude. The results suggest that in nerve terminals of thick tufted L5 pyramidal cells the endogenous mobile Ca2+ buffer is equivalent to less than 0.1 mm BAPTA and that at many release sites of pyramidal cell terminals the Ca2+ channel domains overlap, a situation comparable with that at large calyx-type terminals in the brainstem. PMID:9782165

Emotional self-other voice processing in schizophrenia and its relationship with hallucinations: ERP evidence.

PubMed

Pinheiro, Ana P; Rezaii, Neguine; Rauber, Andréia; Nestor, Paul G; Spencer, Kevin M; Niznikiewicz, Margaret

2017-09-01

Abnormalities in self-other voice processing have been observed in schizophrenia, and may underlie the experience of hallucinations. More recent studies demonstrated that these impairments are enhanced for speech stimuli with negative content. Nonetheless, few studies probed the temporal dynamics of self versus nonself speech processing in schizophrenia and, particularly, the impact of semantic valence on self-other voice discrimination. In the current study, we examined these questions, and additionally probed whether impairments in these processes are associated with the experience of hallucinations. Fifteen schizophrenia patients and 16 healthy controls listened to 420 prerecorded adjectives differing in voice identity (self-generated [SGS] versus nonself speech [NSS]) and semantic valence (neutral, positive, and negative), while EEG data were recorded. The N1, P2, and late positive potential (LPP) ERP components were analyzed. ERP results revealed group differences in the interaction between voice identity and valence in the P2 and LPP components. Specifically, LPP amplitude was reduced in patients compared with healthy subjects for SGS and NSS with negative content. Further, auditory hallucinations severity was significantly predicted by LPP amplitude: the higher the SAPS "voices conversing" score, the larger the difference in LPP amplitude between negative and positive NSS. The absence of group differences in the N1 suggests that self-other voice processing abnormalities in schizophrenia are not primarily driven by disrupted sensory processing of voice acoustic information. The association between LPP amplitude and hallucination severity suggests that auditory hallucinations are associated with enhanced sustained attention to negative cues conveyed by a nonself voice. © 2017 Society for Psychophysiological Research.

Task-induced Changes in Idiopathic Infantile Nystagmus Vary with Gaze.

PubMed

Salehi Fadardi, Marzieh; Bathke, Arne C; Harrar, Solomon W; Abel, Larry Allen

2017-05-01

Investigations of infantile nystagmus syndrome (INS) at center or at the null position have reported that INS worsens when visual demand is combined with internal states, e.g. stress. Visual function and INS parameters such as foveation time, frequency, amplitude, and intensity can also be influenced by gaze position. We hypothesized that increases from baseline in visual demand and mental load would affect INS parameters at the null position differently than at other gaze positions. Eleven participants with idiopathic INS were asked to determine the direction of Tumbling-E targets, whose visual demand was varied through changes in size and contrast, using a staircase procedure. Targets appeared between ±25° in 5° steps. The task was repeated with both mental arithmetic and time restriction to impose higher mental load, confirmed through subjective ratings and concurrent physiological measurements. Within-subject comparisons were limited to the null and 15° away from it. No significant main effects of task on any INS parameters were found. At both locations, high mental load worsened task performance metrics, i.e. lowest contrast (P = .001) and smallest optotype size reached (P = .012). There was a significant interaction between mental load and gaze position for foveation time (P = .02) and for the smallest optotype reached (P = .028). The increase in threshold optotype size from the low to high mental load was greater at the null than away from it. During high visual demand, foveation time significantly decreased from baseline at the null as compared to away from it (mean difference ± SE: 14.19 ± 0.7 msec; P = .010). Under high visual demand, the effects of increased mental load on foveation time and visual task performance differed at the null as compared to 15° away from it. Assessment of these effects could be valuable when evaluating INS clinically and when considering its impact on patients' daily activities.

Assessment of otoacoustic emission suppression in women with migraine and phonophobia.

PubMed

Joffily, Lucia; de Melo Tavares de Lima, Marco Antônio; Vincent, Maurice Borges; Frota, Silvana Maria Monte Coelho

2016-05-01

Given that the medial olivocochlear efferent system reduces the amplitude of otoacoustic emissions (OAE), the aim of this study was to establish whether such a pathway is affected in women with migraine and phonophobia by means of OAE suppression testing. In this prospective case-control study, 55 women (29 with migraine and phonophobia and 26 healthy women) were subjected to transient-evoked otoacoustic emission (TEOAE) testing at frequencies from 1 to 4 kHz. The amplitudes of the TEOAE response before and after exposure to contralateral noise and the magnitude of TEOAE suppression were assessed. The average TEOAE amplitudes in conditions with and without exposure to contralateral noise were not significantly different between the groups. However, the magnitude of TEOAE suppression was lower in the group with migraine; that difference was only statistically significant for frequencies 1 and 1.5 kHz (p = 0.042 and p = 0.004, respectively). In this study, women with migraine and phonophobia exhibited deficits in OAE suppression, which points to a disorder affecting the medial olivocochlear efferent system.

A physical model study of converted wave amplitude variation in a reservoir of systematically aligned vertical fractures

NASA Astrophysics Data System (ADS)

Chang, C.; Sun, L.; Lin, C.; Chang, Y.; Tseng, P.

2013-12-01

The existence of fractures not only provides spaces for the residence of oils and gases reside, but it also creates pathways for migration. Characterizing a fractured reservoir thus becomes an important subject and has been widely studied by exploration geophysicists and drilling engineers. In seismic anisotropy, a reservoir of systematically aligned vertical fractures (SAVF) is often treated as a transversely isotropic medium (TIM) with a horizontal axis of symmetry (HTI). Subjecting to HTI, physical properties vary in azimuth. P-wave reflection amplitude, which is susceptible to vary in azimuth, is one of the most popular seismic attributes which is widely used to delineate the fracture strike of an SAVF reservoir. Instead of going further on analyzing P-wave signatures, in this study, we focused on evaluating the feasibility of orienting the fracture strike of an SAVF reservoir using converted (C-) wave amplitude. For a C-wave is initiated by a downward traveling P-wave that is converted on reflection to an upcoming S-wave; the behaviors of both P- and S-waves should be theoretically woven in a C-wave. In our laboratory work, finite offset reflection experiments were carried out on the azimuthal plane of a HTI model at two different offset intervals. To demonstrate the azimuthal variation of C-wave amplitude in a HTI model, reflections were acquired along the principal symmetry directions and the diagonal direction of the HTI model. Inheriting from phenomenon of S-wave splitting in a transversely isotropic medium (TIM), P-waves get converted into both the fast (S1) and slow (S2) shear modes at all azimuths outside the vertical symmetry planes, thus producing split PS-waves (PS1 and PS2). In our laboratory data, the converted PS1- (C1-) wave were observed and identified. As the azimuth varies from the strike direction to the strike normal, C1-wave amplitude exhibits itself in a way of weakening and can be view from the common-reflection-point (CRP) gathers. Therefore, in conjunction with the azimuthal velocity and the amplitude variations in the P-wave and the azimuthal polarization of the S-wave, the azimuthal variation of C-wave amplitude which is experimentally demonstrated could be considered as a valuable seismic attribute in orienting the fracture strike of a SAVF reservoir. (Key words: converted wave, transversely isotropic medium, physical modeling, amplitude, fracture)

Using Dual Regression to Investigate Network Shape and Amplitude in Functional Connectivity Analyses

PubMed Central

Nickerson, Lisa D.; Smith, Stephen M.; Öngür, Döst; Beckmann, Christian F.

2017-01-01

Independent Component Analysis (ICA) is one of the most popular techniques for the analysis of resting state FMRI data because it has several advantageous properties when compared with other techniques. Most notably, in contrast to a conventional seed-based correlation analysis, it is model-free and multivariate, thus switching the focus from evaluating the functional connectivity of single brain regions identified a priori to evaluating brain connectivity in terms of all brain resting state networks (RSNs) that simultaneously engage in oscillatory activity. Furthermore, typical seed-based analysis characterizes RSNs in terms of spatially distributed patterns of correlation (typically by means of simple Pearson's coefficients) and thereby confounds together amplitude information of oscillatory activity and noise. ICA and other regression techniques, on the other hand, retain magnitude information and therefore can be sensitive to both changes in the spatially distributed nature of correlations (differences in the spatial pattern or “shape”) as well as the amplitude of the network activity. Furthermore, motion can mimic amplitude effects so it is crucial to use a technique that retains such information to ensure that connectivity differences are accurately localized. In this work, we investigate the dual regression approach that is frequently applied with group ICA to assess group differences in resting state functional connectivity of brain networks. We show how ignoring amplitude effects and how excessive motion corrupts connectivity maps and results in spurious connectivity differences. We also show how to implement the dual regression to retain amplitude information and how to use dual regression outputs to identify potential motion effects. Two key findings are that using a technique that retains magnitude information, e.g., dual regression, and using strict motion criteria are crucial for controlling both network amplitude and motion-related amplitude effects, respectively, in resting state connectivity analyses. We illustrate these concepts using realistic simulated resting state FMRI data and in vivo data acquired in healthy subjects and patients with bipolar disorder and schizophrenia. PMID:28348512

Variability of maximum systolic amplitude of ΔZ/Δt curve in pregnancy. Perennial observations

NASA Astrophysics Data System (ADS)

Ilyin, I.; Karpov, A.; Korotkova, M.

2010-04-01

Maximum systolic amplitude is quite an important component of the impedance cardiogram ΔZ/Δt curve. Its values make it possible to calculate many hemodynamic indices. Therefore it is necessary to keep informed about monthly, annual and perennial maximum systolic amplitude trend. We can produce the measuring data of the maximum systolic amplitude for a fifteen-year period (from 1994 to 2009). The impedance cardiograms were obtained with the help of an electric impedance analyzer "RA-5" (1 mA, 70 kHz) with disk ECG electrodes. The data analyzed were taken from the pregnant women with non-complicated pregnancy (n=5709). We have analyzed the average monthly and annual changes of the maximum systolic amplitude ΔZ/Δt curve. It allowed us to reveal the six-year periodicity of the maximum systolic amplitude changes. There were discovered statistically significant peak values difference of the amplitude (p>0.001). The data obtained should be taken into consideration when using impedance cardiography in clinical practice. The article is supplied with tables and diagrams.

Dynamic mechanical measurement of the viscoelasticity of single adherent cells

NASA Astrophysics Data System (ADS)

Corbin, Elise A.; Adeniba, Olaoluwa O.; Ewoldt, Randy H.; Bashir, Rashid

2016-02-01

Many recent studies on the viscoelasticity of individual cells link mechanics with cellular function and health. Here, we introduce a measurement of the viscoelastic properties of individual human colon cancer cells (HT-29) using silicon pedestal microelectromechanical systems (MEMS) resonant sensors. We demonstrate that the viscoelastic properties of single adherent cells can be extracted by measuring a difference in vibrational amplitude of our resonant sensor platform. The magnitude of vibration of the pedestal sensor is measured using a laser Doppler vibrometer (LDV). A change in amplitude of the sensor, compared with the driving amplitude (amplitude ratio), is influenced by the mechanical properties of the adhered cells. The amplitude ratio of the fixed cells was greater than the live cells, with a p-value <0.0001. By combining the amplitude shift with the resonant frequency shift measure, we determined the elastic modulus and viscosity values of 100 Pa and 0.0031 Pa s, respectively. Our method using the change in amplitude of resonant MEMS devices can enable the determination of a refined solution space and could improve measuring the stiffness of cells.

Scotopic electroretinography in fishing cat (Prionailurus viverrinus) and leopard cat (Prionailurus bengalensis).

PubMed

Sussadee, Metita; Vorawattanatham, Narathip; Pinyopummin, Anuchai; Phavaphutanon, Janjira; Thayananuphat, Aree

2017-05-01

To establish baseline normal scotopic electroretinograpic (ERG) parameters for two wild cat species: fishing cats (FC) and leopard cats (LC). Twelve normal, FC and eight LC kept in the Chiang Mai Night Safari Zoo, Thailand. The mean ages of FC and LC were 7.08 and 5.00 years, respectively. All animals were studied using a standard scotopic protocol of a portable, handheld, multi-species electroretinography (HMsERG). There were significant differences in the means of ERG b-wave amplitude of the rod response (Rod, 0.01 cd.s/m 2 ), a- and b-wave amplitudes of standard light intensity of rod and cone response (Std R&C, 3 cd.s/m 2 ) and b-wave amplitude of high light intensity of rod and cone response (Hi-int R&C, 10 cd.s/m 2 ) with LC having higher amplitudes than FC. There was no significant difference in a- and b- wave implicit time except for the b-wave of Hi-int (P=0.03). No significant differences were observed in b/a amplitude ratios. Data from this report provides reference values for scotopic ERG measurements in these two wild cat species. It showed that the normal scotopic ERG responses have some differences between the two species which might be due to the skull conformation, eye size or physiology of the retina. © 2016 American College of Veterinary Ophthalmologists.

Effects of the P2 M-band flux asymmetry of laser-driven gold Hohlraums on the implosion of ICF ignition capsule

NASA Astrophysics Data System (ADS)

Li, Yongsheng; Gu, Jianfa; Wu, Changshu; Song, Peng; Dai, Zhensheng; Li, Shuanggui; Li, Xin; Kang, Dongguo; Gu, Peijun; Zheng, Wudi; Zou, Shiyang; Ding, Yongkun; Lan, Ke; Ye, Wenhua; Zhang, Weiyan

2016-07-01

Low-mode asymmetries in the laser-indirect-drive inertial confinement fusion implosion experiments conducted on the National Ignition Facility [G. H. Miller et al., Nucl. Fusion 44, S228 (2004)] are deemed the main obstacles hindering further improvement of the nuclear performance of deuterium-tritium-layered capsules. The dominant seeds of these asymmetries include the P2 and P4 asymmetries of x-ray drives and P2 asymmetry introduced by the supporting "tent." Here, we explore the effects of another possible seed that can lead to low-mode asymmetric implosions, i.e., the M-band flux asymmetry (MFA) in laser-driven cylindrical gold Hohlraums. It is shown that the M-band flux facilitates the ablation and acceleration of the shell, and that positive P2 MFAs can result in negative P2 asymmetries of hot spots and positive P2 asymmetries of shell's ρR. An oblate or toroidal hot spot, depending on the P2 amplitude of MFA, forms at stagnation. The energy loss of such a hot spot via electron thermal conduction is seriously aggravated not only due to the enlarged hot spot surface but also due to the vortices that develop and help transferring thermal energy from the hotter center to the colder margin of such a hot spot. The cliffs of nuclear performance for the two methodologies of applying MFA (i.e., symmetric flux in the presence of MFA and MFA added for symmetric soft x-ray flux) are obtained locating at 9.5% and 5.0% of P2/P0 amplitudes, respectively.

Effects of the P2 M-band flux asymmetry of laser-driven gold Hohlraums on the implosion of ICF ignition capsule

DOE Office of Scientific and Technical Information (OSTI.GOV)

Li, Yongsheng; Graduate School, China Academy of Engineering Physics, Beijing 100088; Gu, Jianfa

Low-mode asymmetries in the laser-indirect-drive inertial confinement fusion implosion experiments conducted on the National Ignition Facility [G. H. Miller et al., Nucl. Fusion 44, S228 (2004)] are deemed the main obstacles hindering further improvement of the nuclear performance of deuterium-tritium-layered capsules. The dominant seeds of these asymmetries include the P2 and P4 asymmetries of x-ray drives and P2 asymmetry introduced by the supporting “tent.” Here, we explore the effects of another possible seed that can lead to low-mode asymmetric implosions, i.e., the M-band flux asymmetry (MFA) in laser-driven cylindrical gold Hohlraums. It is shown that the M-band flux facilitates themore » ablation and acceleration of the shell, and that positive P2 MFAs can result in negative P2 asymmetries of hot spots and positive P2 asymmetries of shell's ρR. An oblate or toroidal hot spot, depending on the P2 amplitude of MFA, forms at stagnation. The energy loss of such a hot spot via electron thermal conduction is seriously aggravated not only due to the enlarged hot spot surface but also due to the vortices that develop and help transferring thermal energy from the hotter center to the colder margin of such a hot spot. The cliffs of nuclear performance for the two methodologies of applying MFA (i.e., symmetric flux in the presence of MFA and MFA added for symmetric soft x-ray flux) are obtained locating at 9.5% and 5.0% of P2/P0 amplitudes, respectively.« less

What can stimulus polarity and interphase gap tell us about auditory nerve function in cochlear-implant recipients?

PubMed

Hughes, Michelle L; Choi, Sangsook; Glickman, Erin

2018-03-01

Modeling studies suggest that differences in neural responses between polarities might reflect underlying neural health. Specifically, large differences in electrically evoked compound action potential (eCAP) amplitudes and amplitude-growth-function (AGF) slopes between polarities might reflect poorer peripheral neural health, whereas more similar eCAP responses between polarities might reflect better neural health. The interphase gap (IPG) has also been shown to relate to neural survival in animal studies. Specifically, healthy neurons exhibit larger eCAP amplitudes, lower thresholds, and steeper AGF slopes for increasing IPGs. In ears with poorer neural survival, these changes in neural responses are generally less apparent with increasing IPG. The primary goal of this study was to examine the combined effects of stimulus polarity and IPG within and across subjects to determine whether both measures represent similar underlying mechanisms related to neural health. With the exception of one measure in one group of subjects, results showed that polarity and IPG effects were generally not correlated in a systematic or predictable way. This suggests that these two effects might represent somewhat different aspects of neural health, such as differences in site of excitation versus integrative membrane characteristics, for example. Overall, the results from this study suggest that the underlying mechanisms that contribute to polarity and IPG effects in human CI recipients might be difficult to determine from animal models that do not exhibit the same anatomy, variance in etiology, electrode placement, and duration of deafness as humans. Copyright © 2017 Elsevier B.V. All rights reserved.

Dysfunctional information processing during an auditory event-related potential task in individuals with Internet gaming disorder

PubMed Central

Park, M; Choi, J-S; Park, S M; Lee, J-Y; Jung, H Y; Sohn, B K; Kim, S N; Kim, D J; Kwon, J S

2016-01-01

Internet gaming disorder (IGD) leading to serious impairments in cognitive, psychological and social functions has gradually been increasing. However, very few studies conducted to date have addressed issues related to the event-related potential (ERP) patterns in IGD. Identifying the neurobiological characteristics of IGD is important to elucidate the pathophysiology of this condition. P300 is a useful ERP component for investigating electrophysiological features of the brain. The aims of the present study were to investigate differences between patients with IGD and healthy controls (HCs), with regard to the P300 component of the ERP during an auditory oddball task, and to examine the relationship of this component to the severity of IGD symptoms in identifying the relevant neurophysiological features of IGD. Twenty-six patients diagnosed with IGD and 23 age-, sex-, education- and intelligence quotient-matched HCs participated in this study. During an auditory oddball task, participants had to respond to the rare, deviant tones presented in a sequence of frequent, standard tones. The IGD group exhibited a significant reduction in response to deviant tones compared with the HC group in the P300 amplitudes at the midline centro-parietal electrode regions. We also found a negative correlation between the severity of IGD and P300 amplitudes. The reduced amplitude of the P300 component in an auditory oddball task may reflect dysfunction in auditory information processing and cognitive capabilities in IGD. These findings suggest that reduced P300 amplitudes may be candidate neurobiological marker for IGD. PMID:26812042

Dysfunctional information processing during an auditory event-related potential task in individuals with Internet gaming disorder.

PubMed

Park, M; Choi, J-S; Park, S M; Lee, J-Y; Jung, H Y; Sohn, B K; Kim, S N; Kim, D J; Kwon, J S

2016-01-26

Internet gaming disorder (IGD) leading to serious impairments in cognitive, psychological and social functions has gradually been increasing. However, very few studies conducted to date have addressed issues related to the event-related potential (ERP) patterns in IGD. Identifying the neurobiological characteristics of IGD is important to elucidate the pathophysiology of this condition. P300 is a useful ERP component for investigating electrophysiological features of the brain. The aims of the present study were to investigate differences between patients with IGD and healthy controls (HCs), with regard to the P300 component of the ERP during an auditory oddball task, and to examine the relationship of this component to the severity of IGD symptoms in identifying the relevant neurophysiological features of IGD. Twenty-six patients diagnosed with IGD and 23 age-, sex-, education- and intelligence quotient-matched HCs participated in this study. During an auditory oddball task, participants had to respond to the rare, deviant tones presented in a sequence of frequent, standard tones. The IGD group exhibited a significant reduction in response to deviant tones compared with the HC group in the P300 amplitudes at the midline centro-parietal electrode regions. We also found a negative correlation between the severity of IGD and P300 amplitudes. The reduced amplitude of the P300 component in an auditory oddball task may reflect dysfunction in auditory information processing and cognitive capabilities in IGD. These findings suggest that reduced P300 amplitudes may be candidate neurobiological marker for IGD.

Fetal motor activity and maternal cortisol

PubMed Central

DiPietro, Janet A.; Kivlighan, Katie T.; Costigan, Kathleen A.; Laudenslager, Mark L.

2009-01-01

The contemporaneous association between maternal salivary cortisol and fetal motor activity was examined at 32 and 36 weeks gestation. Higher maternal cortisol was positively associated with the amplitude of fetal motor activity at 32 weeks, r(48) = .39, p < .01, and 36 weeks, r(77)=.27, p < .05, and the amount of time fetuses spent moving at 32 weeks during the 50 minute observation period, r(48) = 33, p < .05. Observation of periods of unusually intense fetal motor activity were more common in fetuses of women with higher cortisol, Mann-Whitney U = 58.5. There were no sex differences in fetal motor activity, but the associations between maternal cortisol and fetal motor amplitude and overall movement were significantly stronger for male than female fetuses. PMID:19630038

The influence of shear-velocity heterogeneity on ScS2/ScS amplitude ratios and estimates of Q in the mantle

NASA Astrophysics Data System (ADS)

Ritsema, J.; Chaves, C. A. M.

2016-12-01

Regional waveforms of deep-focus Tonga-Fiji earthquakes indicate anomalous traveltime differences (ScS2-ScS) and amplitude ratios (ScS2/ScS) of the phases ScS and ScS2. The correlation between the ScS2-ScS delay time and the ScS2/ScS amplitude ratio suggests that shear-wave apparent Q in the mantle below the Tonga-Fiji region is highest when shear-wave velocities are lowest. This observation is unexpected if temperature variations were responsible for the seismic anomalies. Using spectral-element-method waveform simulations for four tomographic models we demonstrate that focusing and scattering of shear waves by long-wavelength 3D heterogeneity in the mantle may overwhelm the signal from intrinsic attenuation in long-period ScS2/ScS amplitude ratios. The tomographic models reproduce the variability in recorded ScS2-ScS difference times and ScS2/ScS amplitude ratios. Variations in shear-wave attenuation (i.e., the quality factor Q) are not necessary to explain the data. An explanation for slow shear wave propagation without intrinsic attenuation does not require a creative solution from mineral physics.

The influence of shear-velocity heterogeneity on ScS2/ScS amplitude ratios and estimates of Q in the mantle

NASA Astrophysics Data System (ADS)

Chaves, Carlos A. M.; Ritsema, Jeroen

2016-08-01

Regional waveforms of deep-focus Tonga-Fiji earthquakes indicate anomalous traveltime differences (ScS2-ScS) and amplitude ratios (ScS2/ScS) of the phases ScS and ScS2. The correlation between the ScS2-ScS delay time and the ScS2/ScS amplitude ratio suggests that shear wave apparent Q in the mantle below the Tonga-Fiji region is highest when shear wave velocities are lowest. This observation is unexpected if temperature variations were responsible for the seismic anomalies. Using spectral element method waveform simulations for four tomographic models, we demonstrate that focusing and scattering of shear waves by long-wavelength 3-D heterogeneity in the mantle may overwhelm the signal from intrinsic attenuation in long-period ScS2/ScS amplitude ratios. The tomographic models reproduce the trends in recorded ScS2-ScS difference times and ScS2/ScS amplitude ratios. Although they cannot be ruled out, variations in shear wave attenuation (i.e., the quality factor Q) are not necessary to explain the data.

Gap prepulse inhibition of the auditory late response in healthy subjects.

PubMed

Ku, Yunseo; Ahn, Joong Woo; Kwon, Chiheon; Suh, Myung-Whan; Lee, Jun Ho; Oh, Seung Ha; Kim, Hee Chan

2015-11-01

The gap-startle paradigm has been used as a behavioral method for tinnitus screening in animal studies. This study aimed to investigate gap prepulse inhibition (GPI) of the auditory late response (ALR) as the objective response of the gap-intense sound paradigm in humans. ALRs were recorded in response to gap-intense and no-gap-intense sound stimuli in 27 healthy subjects. The amplitudes of the baseline-to-peak (N1, P2, and N2) and the peak-to-peak (N1P2 and P2N2) were compared between two averaged ALRs. The variations in the inhibition ratios of N1P2 and P2N2 during the experiment were analyzed by increasing stimuli repetitions. The effect of stimulus parameter adjustments on GPI ratios was evaluated. No-gap-intense sound stimuli elicited greater peak amplitudes than gap-intense sound stimuli, and significant differences were found across all peaks. The overall mean inhibition ratios were significantly lower than 1.0, where the value 1.0 indicates that there were no differences between gap-intense and no-gap-intense sound responses. The initial decline in GPI ratios was shown in N1P2 and P2N2 complexes, and this reduction was nearly complete after 100 stimulus repetitions. Significant effects of gap length and interstimulus interval on GPI ratios were observed. We found significant inhibition of ALR peak amplitudes in performing the gap-intense sound paradigm in healthy subjects. The N1P2 complex represented GPI well in terms of suppression degree and test-retest reliability. Our findings offer practical information for the comparative study of healthy subjects and tinnitus patients using the gap-intense sound paradigm with the ALR. © 2015 Society for Psychophysiological Research.

Neuromuscular Characterization of the Urethra in Continent Women

PubMed Central

Kenton, Kimberly; Mueller, Elizabeth; Brubaker, Linda

2011-01-01

Objectives To describe quantitative urethral function parameters in a racially diverse group of continent women. Materials and Methods Following Institutional Review Board approval, we recruited women without urinary incontinence from the community. To be considered continent, participants answered “never” to the first six questions on the stress subscale of the Medical, Epidemiologic, and Social Aspects of Aging urinary incontinence (MESA) questionnaire. Participants all underwent quantitative concentric urethral electromyography (EMG) and urodynamic testing (UDS). Results Thirty-one women with a mean±SD age of 39±14 years underwent EMG and UDS. The cohort was racially diverse with 13 Caucasians (43%), 13 African Americans (43%), and 4 Hispanics (14%). Body mass index (BMI) (P=.12, .06), age (P=.40, .64), and vaginal parity (P=.53, .76) did not differ by race or ethnicity. We did not detect differences in any EMG parameter by race, ethnicity or vaginally parity. A mean (range) of 30 motor unit action potential analysis (MUP) (10-55) were identified and analyzed in Multi-MUP analysis and 14 (8-21) were identified and analyzed in IP analysis. On average, 37±20% MUPs were polyphasic. Age significantly correlated with several measures of urethral sphincter function. Increasing age was inversely correlated with interference analysis (IP) turns (−.57, p=.001), IP amplitude (r=−.43, p=.02), IP turns/amplitude (r=−.54, p=.003), maximum urethral closure pressures (MUCP) (r=−.41, p=.04). Similarly, MUCP correlated with IP amplitude (r=.38, p=.04). Conclusions This urethral neuromuscular function data on the largest cohort of continent women fully characterized with quantitative urethral EMG demonstrates significant neuropathic MUP changes with advancing age. PMID:22453105

Event-related brain potentials to emotional images and gonadal steroid hormone levels in patients with schizophrenia and paired controls

PubMed Central

Champagne, Julie; Mendrek, Adrianna; Germain, Martine; Hot, Pascal; Lavoie, Marc E.

2014-01-01

Prominent disturbances in the experience, expression, and emotion recognition in patients with schizophrenia have been relatively well documented over the last few years. Furthermore, sex differences in behavior and brain activity, associated with the processing of various emotions, have been reported in the general population and in schizophrenia patients. Others proposed that sex differences should be rather attributed to testosterone, which may play a role in the etiology of schizophrenia. Also, it had been suggested that estradiol may play a protective role in schizophrenia. Surprisingly, few studies investigating this pathology have focused on both brain substrates and gonadal steroid hormone levels, in emotional processing. In the present study, we investigated electrocortical responses related to emotional valence and arousal as well as gonadal steroid hormone levels in patients with schizophrenia. Event-Related Potentials (ERP) were recorded during exposition to emotional pictures in 18 patients with schizophrenia and in 24 control participants paired on intelligence, manual dominance and socioeconomic status. Given their previous sensitivity to emotional and attention processes, the P200, N200 and the P300 were selected for analysis. More precisely, emotional valence generally affects early components (N200), which reflect early process of selective attention, whereas emotional arousal and valence both influences the P300 component, which is related to memory context updating, and stimulus categorization. Results showed that, in the control group, the amplitude of the N200 was significantly more lateralized over the right hemisphere, while there was no such lateralization in patients with schizophrenia. In patients with schizophrenia, significantly smaller anterior P300 amplitude was observed to the unpleasant, compared to the pleasant. That anterior P300 reduction was also correlated with negative symptoms. The N200 and P300 amplitudes were positively correlated with the estradiol level in all conditions, revealing that the N200 and the P300 were reduced, when estradiol level was higher. Conversely, only the P300 amplitude showed positive correlation with the testosterone level. PMID:24966840

Event-related brain potentials to emotional images and gonadal steroid hormone levels in patients with schizophrenia and paired controls.

PubMed

Champagne, Julie; Mendrek, Adrianna; Germain, Martine; Hot, Pascal; Lavoie, Marc E

2014-01-01

Prominent disturbances in the experience, expression, and emotion recognition in patients with schizophrenia have been relatively well documented over the last few years. Furthermore, sex differences in behavior and brain activity, associated with the processing of various emotions, have been reported in the general population and in schizophrenia patients. Others proposed that sex differences should be rather attributed to testosterone, which may play a role in the etiology of schizophrenia. Also, it had been suggested that estradiol may play a protective role in schizophrenia. Surprisingly, few studies investigating this pathology have focused on both brain substrates and gonadal steroid hormone levels, in emotional processing. In the present study, we investigated electrocortical responses related to emotional valence and arousal as well as gonadal steroid hormone levels in patients with schizophrenia. Event-Related Potentials (ERP) were recorded during exposition to emotional pictures in 18 patients with schizophrenia and in 24 control participants paired on intelligence, manual dominance and socioeconomic status. Given their previous sensitivity to emotional and attention processes, the P200, N200 and the P300 were selected for analysis. More precisely, emotional valence generally affects early components (N200), which reflect early process of selective attention, whereas emotional arousal and valence both influences the P300 component, which is related to memory context updating, and stimulus categorization. Results showed that, in the control group, the amplitude of the N200 was significantly more lateralized over the right hemisphere, while there was no such lateralization in patients with schizophrenia. In patients with schizophrenia, significantly smaller anterior P300 amplitude was observed to the unpleasant, compared to the pleasant. That anterior P300 reduction was also correlated with negative symptoms. The N200 and P300 amplitudes were positively correlated with the estradiol level in all conditions, revealing that the N200 and the P300 were reduced, when estradiol level was higher. Conversely, only the P300 amplitude showed positive correlation with the testosterone level.

Abnormalities of P300 before and after antidepressant treatment in depression: an ERP-sLORETA study.

PubMed

Zhou, Lina; Wang, Gaohua; Wang, Huiling

2018-02-07

Despite a wide range of reports on depression-induced P300 changes, it is still debatable whether P300 can return to a pattern characteristic of healthy individuals following antidepressant treatment. Thus, the present study aims to compare P300 and its underlying neural activation in depressed patients before and after antidepressant treatment to explore the brain regions related to pathogenesis and to evaluate the prognosis after treatment. P300 was evoked by the oddball auditory paradigm and collected from 14 sex-matched, age-matched, and education level-matched patients and controls. P300 was also collected in the same patients after treatment. sLORETA was used to explore the source activation of P300 components. Depressed patients before and after antidepressant treatment tended to show lower P300 amplitudes compared with healthy controls, and their P300 amplitudes of F3 electrodes were correlated negatively to their scores on the 24-item Hamilton Depression Rating Scale, the Snaith-Hamilton Pleasure Scale, and the nine-item Patient Health Questionnaire. P300 amplitudes of P4 electrodes were correlated negatively with their scores on the Dysfunctional Attitude Scale. P300 source activation of depressed patients before antidepressant treatment was reduced in the left superior parietal lobule and the precuneus compared with healthy controls and depressed patients after treatment. No difference was found between healthy controls and depressed patients after treatment. The left superior parietal lobule and the precuneus might be therapeutic targets of depression.

Scattering of glue by glue on the light-cone worldsheet: Helicity nonconserving amplitudes

NASA Astrophysics Data System (ADS)

Chakrabarti, D.; Qiu, J.; Thorn, C. B.

2005-09-01

We give the light-cone gauge calculation of the one-loop on-shell scattering amplitudes for gluon-gluon scattering which violate helicity conservation. We regulate infrared divergences by discretizing the p+ integrations, omitting the terms with p+=0. Collinear divergences are absent diagram by diagram for the helicity nonconserving amplitudes. We also employ a novel ultraviolet regulator that is natural for the light-cone worldsheet description of planar Feynman diagrams. We show that these regulators give the known answers for the helicity nonconserving one-loop amplitudes, which do not suffer from the usual infrared vagaries of massless particle scattering. For the maximal helicity violating process we elucidate the physics of the remarkable fact that the loop momentum integrand for the on-shell Green function associated with this process, with a suitable momentum routing of the different contributing topologies, is identically zero. We enumerate the counterterms that must be included to give Lorentz covariant results to this order, and we show that they can be described locally in the light-cone worldsheet formulation of the sum of planar diagrams.

CGRP potentiates excitatory transmission to the circular muscle of guinea-pig colon.

PubMed

Maggi, C A; Giuliani, S; Santicioli, P

1997-04-30

We aimed to assess whether calcitonin gene-related peptide (CGRP) can modulate the release of tachykinins which are the main nonadrenergic noncholinergic (NANC) excitatory transmitters to the circular muscle of the guinea-pig proximal colon. In organ bath experiments, electrical field stimulation (EFS) in the presence of atropine (1 microM) and guanethidine (3 microM) evoked twitch phasic NANC contractions which were abolished by the combined administration of tachykinin NK1 and NK2 receptor antagonists. Human alphaCGRP (CGRP, 1-100 nM) produced a concentration-dependent potentiation of the amplitude of the NANC contractions induced by EFS while salmon calcitonin (up to 1 microM) had no effect. The potentiating effect of CGRP was unaffected by in vitro capsaicin pretreatment (10 microM for 15 min), peptidase inhibitors (captopril, bestatin and thiorphan, 1 microM each), apamin (0.3 microM) plus L-nitroarginine (L-NOARG, 100 microM) and by the CGRP1 receptor antagonist, the C-terminal fragment CGRP(8-37) (1 microM). The NK2 receptor antagonist MEN 10627 which, when administered alone, had only a partial inhibitory effect on the amplitude of NANC twitches, concentration-dependently (10 nM-1 microM) inhibited the potentiating effect of CGRP. CGRP (1-100 nM) produced a concentration-dependent potentiation of the atropine-sensitive cholinergic contractions evoked by EFS in the presence of guanethidine and of tachykinin NK1 and NK2 receptor antagonists. Similar to the effect of CGRP, application of capsaicin (0.1-1 microM) potentiated the amplitude of the NANC contraction to EFS, an effect undergoing complete desensitization upon a second application of the drug. CGRP (0.1 microM) did not affect the contractile action of a submaximally effective concentration of neurokinin A (2 nM) while it inhibited that induced by substance P (2 nM). In sucrose gap, single pulse EFS in the presence of atropine (1 microM) and guanethidine (3 microM) induced an inhibitory junction potential (i.j.p.) and a small excitatory junction potential (e.j.p.). CGRP (0.1 microM) produced membrane hyperpolarization and relaxation without affecting i.j.p. amplitude but concomitantly increased the e.j.p. amplitude to induce a contraction in correspondence to each electrical pulse. In the presence of the NK1 receptor antagonist, GR 82334 (3 microM), the membrane hyperpolarization and relaxation produced by CGRP and the EFS-evoked i.j.p. were unaffected, while the potentiating effect of CGRP on the EFS-evoked NANC e.j.p. and the corresponding contraction were abolished. We conclude that, in addition to the previously characterized direct smooth muscle relaxant action via CGRP1 receptors (Maggi et al. Regulatory Peptides 61, 27-36, 1996), CGRP also induces a remarkable potentiation of excitatory neurotransmission to the circular muscle of the guinea-pig colon via CGRP2 receptors. The latter effect, documented in this study, is evidenced on both the atropine-sensitive and the atropine-resistant (tachykinin-mediated) components of excitatory transmission: this effect does not involve mediator(s) release from capsaicin-sensitive primary afferent nerves, nor inhibition of peptide degradation or modulation of NANC inhibitory transmission.

Maturational changes in the thermoalgesic system in humans from childhood to adulthood revealed by CO(2) laser evoked brain potentials following cutaneous heat stimuli.

PubMed

Opsommer, E; Plaghki, L

2001-12-28

Possible maturational changes in the thermoalgesic system were studied by reaction times (RT) and late (Adelta-fibre) laser evoked potentials (LEPs) following CO(2) laser heat stimulation of the hand in healthy children (n=12) and young adults (n=12). In children (10+/-2 years) LEPs presented a negative-positive complex with maximum amplitude (peak-to-peak 71+/-35 microV) at the vertex and latencies of 248+/-82 and 433+/-104 ms, respectively. As compared to adults (24+/-3 years), children had a significant increased peak-to-peak amplitude (+25.7 microV; P=0.03) although no difference in latencies and topography. Median RT (710 ms) was also significantly increased (+312 ms; P<0.005) in children. A decrease in RT and late LEP amplitude from childhood to adulthood may reflect aspects of maturation in sensory processing of the thermoalgesic system.

Does electropolishing improve the low-cycle fatigue behavior of a nickel-titanium rotary instrument in hypochlorite?

PubMed

Cheung, Gary S P; Shen, Ya; Darvell, Brian W

2007-10-01

The purpose of this study was to compare the low-cycle fatigue (LCF) behavior of electropolished and nonelectropolished nickel-titanium (NiTi) instruments of the same design in hypochlorite. Forty-five electropolished and 62 nonelectropolished NiTi engine files were subjected to rotational bending at various curvatures in 1.2% hypochlorite solution. Number of revolutions to failure, crack-initiation sites, extent of slow crack extension into the fracture cross-section, and surface-strain amplitude were noted. A linear relationship was found between LCF life and surface-strain amplitude for both groups, with no discernible difference between the two (p > 0.05). No electropolished instrument showed more than one crack origin, significantly fewer than for the nonelectropolished instruments (p < 0.05). The square root of crack extension and strain amplitude were inversely related. Although surface smoothness is enhanced by electropolishing, this did not protect the instrument from LCF failure.

Task-related enhancement in corticomotor excitability during haptic sensing with the contra- or ipsilateral hand in young and senior adults.

PubMed

Master, Sabah; Tremblay, François

2012-03-14

Haptic sensing with the fingers represents a unique class of manipulative actions, engaging motor, somatosensory and associative areas of the cortex while requiring only minimal forces and relatively simple movement patterns. Using transcranial magnetic stimulation (TMS), we investigated task-related changes in motor evoked potential (MEP) amplitude associated with unimanual haptic sensing in two related experiments. In Experiment I, we contrasted changes in the excitability of the hemisphere controlling the task hand in young and old adults under two trial conditions, i.e. when participants either touched a fine grating (smooth trials) or touched a coarse grating to detect its groove orientation (grating trials). In Experiment II, the same contrast between tasks was performed but with TMS applied over the hemisphere controlling the resting hand, while also addressing hemispheric (right vs. left) and age differences. In Experiment I, a main effect of trial type on MEP amplitude was detected (p = 0.001), MEPs in the task hand being ~50% larger during grating than smooth trials. No interaction with age was detected. Similar results were found for Experiment II, trial type having a large effect on MEP amplitude in the resting hand (p < 0.001) owing to selective increase in MEP size (~2.6 times greater) for grating trials. No interactions with age or side (right vs. left) were detected. Collectively, these results indicate that adding a haptic component to a simple unilateral finger action can elicit robust corticomotor facilitation not only in the working hemisphere but also in the opposite hemisphere. The fact that this facilitation seems well preserved with age, when task difficulty is adjusted, has some potential clinical implications.

Gratitude intervention modulates P3 amplitude in a temporal discounting task.

PubMed

Patalano, Andrea L; Lolli, Sydney L; Sanislow, Charles A

2018-06-23

Gratitude has been shown to reduce economic impatience. In particular, individuals induced to experience heightened gratitude are more willing to choose delayed larger rewards over immediate smaller rewards (i.e., they have lower discounting rates) than those in a neutral condition. Using the event-related potential (ERP) method, we investigated the relation between gratitude level and neurophysiological correlates. Of interest was motivated information processing, as indexed by the P3 component. Participants were administered a gratitude or a neutral mood induction followed by a temporal discounting task (choosing between a fixed immediate reward versus a future reward that varied across trials) while electroencephalogram (EEG) activity was recorded. Individuals in the gratitude condition had greater P3 amplitude, suggesting greater attention to the future-reward option (the choice option that varied across trials), even when this option was not selected, and providing the first evidence of gratitude-induced changes in electrophysiological activity. Copyright © 2018. Published by Elsevier B.V.

Influence of aggression on information processing in the emotional stroop task--an event-related potential study.

PubMed

Bertsch, Katja; Böhnke, Robina; Kruk, Menno R; Naumann, Ewald

2009-01-01

Aggression is a common behavior which has frequently been explained as involving changes in higher level information processing patterns. Although researchers have started only recently to investigate information processing in healthy individuals while engaged in aggressive behavior, the impact of aggression on information processing beyond an aggressive encounter remains unclear. In an event-related potential study, we investigated the processing of facial expressions (happy, angry, fearful, and neutral) in an emotional Stroop task after experimentally provoking aggressive behavior in healthy participants. Compared to a non-provoked group, these individuals showed increased early (P2) and late (P3) positive amplitudes for all facial expressions. For the P2 amplitude, the effect of provocation was greatest for threat-related expressions. Beyond this, a bias for emotional expressions, i.e., slower reaction times to all emotional expressions, was found in provoked participants with a high level of trait anger. These results indicate significant effects of aggression on information processing, which last beyond the aggressive encounter even in healthy participants.

Neuroscientific evidence for defensive avoidance of fear appeals

PubMed Central

Kessels, Loes T E; Ruiter, Robert A C; Wouters, Liesbeth; Jansma, Bernadette M

2014-01-01

Previous studies indicate that people respond defensively to threatening health information, especially when the information challenges self-relevant goals. The authors investigated whether reduced acceptance of self-relevant health risk information is already visible in early attention allocation processes. In two experimental studies, participants were watching high- and low-threat health commercials, and at the same time had to pay attention to specific odd auditory stimuli in a sequence of frequent auditory stimuli (odd ball paradigm). The amount of attention allocation was measured by recording event-related brain potentials (i.e., P300 ERPs) and reaction times. Smokers showed larger P300 amplitudes in response to the auditory targets while watching high-threat instead of low-threat anti-smoking commercials. In contrast, non-smokers showed smaller P300 amplitudes during watching high as opposed to low threat anti-smoking commercials. In conclusion, the findings provide further neuroscientific support for the hypothesis that threatening health information causes more avoidance responses among those for whom the health threat is self-relevant. PMID:24811878

Relativistic electron scattering by magnetosonic waves: Effects of discrete wave emission and high wave amplitudes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Artemyev, A. V., E-mail: ante0226@gmail.com; Mourenas, D.; Krasnoselskikh, V. V.

2015-06-15

In this paper, we study relativistic electron scattering by fast magnetosonic waves. We compare results of test particle simulations and the quasi-linear theory for different spectra of waves to investigate how a fine structure of the wave emission can influence electron resonant scattering. We show that for a realistically wide distribution of wave normal angles θ (i.e., when the dispersion δθ≥0.5{sup °}), relativistic electron scattering is similar for a wide wave spectrum and for a spectrum consisting in well-separated ion cyclotron harmonics. Comparisons of test particle simulations with quasi-linear theory show that for δθ>0.5{sup °}, the quasi-linear approximation describes resonantmore » scattering correctly for a large enough plasma frequency. For a very narrow θ distribution (when δθ∼0.05{sup °}), however, the effect of a fine structure in the wave spectrum becomes important. In this case, quasi-linear theory clearly fails in describing accurately electron scattering by fast magnetosonic waves. We also study the effect of high wave amplitudes on relativistic electron scattering. For typical conditions in the earth's radiation belts, the quasi-linear approximation cannot accurately describe electron scattering for waves with averaged amplitudes >300 pT. We discuss various applications of the obtained results for modeling electron dynamics in the radiation belts and in the Earth's magnetotail.« less

Antisocial behaviour and psychopathy: Uncovering the externalizing link in the P3 modulation.

PubMed

Pasion, Rita; Fernandes, Carina; Pereira, Mariana R; Barbosa, Fernando

2017-03-22

In 2009, Gao and Raine's meta-analysis analysed P3 modulation over the antisocial spectrum. However, some questions remained open regarding the P3 modulation patterns across impulsive and violent manifestations of antisocial behaviour, phenotypic components of psychopathy, and P3 components. A systematic review of 36 studies was conducted (N=3514) to extend previous results and to address these unresolved questions. A clear link between decreased P3 amplitude and antisocial behaviour was found. In psychopathy, dimensional approaches become more informative than taxonomic models. Distinct etiological pathways of psychopathy were evidenced in cognitive tasks: impulsive-antisocial psychopathic traits mainly predicted blunted P3 amplitude, while interpersonal-affective psychopathic traits explained enhanced P3 amplitude. Supporting the low fear hypothesis, the interpersonal-affective traits were associated with reduced P3 amplitude in emotional-affective learning tasks. From the accumulated knowledge we propose a framework of P3 amplitude modulation that uncovers the externalizing link between psychopathy and antisocial behaviour. However, the main hypotheses are exploratory and call for more data before stablishing robust conclusions. Copyright © 2017 Elsevier Ltd. All rights reserved.

The correlation between the amplitude of Osborn wave and core body temperature.

PubMed

Omar, Hesham R; Camporesi, Enrico M

2015-08-01

Several reports illustrate an inverse correlation between the Osborn wave (J wave) amplitude and core body temperature. We attempted to study the strength of this correlation. We reviewed all articles reporting hypothermic J waves from 1950-2014 for patient demographics, core body temperature in Celsius (°C), amplitude of the J wave in millimeters (mm), lead with the highest amplitude of J wave, presence of acidosis, PO2, electrolytes and outcome. In cases with more than one electrocardiogram (ECG), the respective core body temperature and J wave amplitude of each ECG were recorded. The main study outcome is to evaluate the correlation between the J wave amplitude and core body temperature in the admission ECG. We have also examined the strength of this relationship in cases with more than one ECG. We attempted to find the most frequent lead that recorded the highest amplitude of the J wave in addition to the correlation between the amplitude of J wave and pH. We found 64 articles comprising a total of 68 cases. When analyzing only cases with more than one reported ECG, there was a strong inverse correlation (r = - 0.682, p<0.001) between J wave amplitude and body temperature: however, when analyzing admission ECG of all cases, the correlation was only moderate (r = - 0.410, p<0.001). The lead with the highest amplitude of the J wave was V4 (44% of the cases, p<0.001) followed by V3 (23.7% of the cases, p<0.001). The amplitude of the J wave in the admission ECG of hypothermic patients may not accurately predict the core body temperature. © The European Society of Cardiology 2014.

Insensitivity to Fearful Emotion for Early ERP Components in High Autistic Tendency Is Associated with Lower Magnocellular Efficiency.

PubMed

Burt, Adelaide; Hugrass, Laila; Frith-Belvedere, Tash; Crewther, David

2017-01-01

Low spatial frequency (LSF) visual information is extracted rapidly from fearful faces, suggesting magnocellular involvement. Autistic phenotypes demonstrate altered magnocellular processing, which we propose contributes to a decreased P100 evoked response to LSF fearful faces. Here, we investigated whether rapid processing of fearful facial expressions differs for groups of neurotypical adults with low and high scores on the Autistic Spectrum Quotient (AQ). We created hybrid face stimuli with low and high spatial frequency filtered, fearful, and neutral expressions. Fearful faces produced higher amplitude P100 responses than neutral faces in the low AQ group, particularly when the hybrid face contained a LSF fearful expression. By contrast, there was no effect of fearful expression on P100 amplitude in the high AQ group. Consistent with evidence linking magnocellular differences with autistic personality traits, our non-linear VEP results showed that the high AQ group had higher amplitude K2.1 responses than the low AQ group, which is indicative of less efficient magnocellular recovery. Our results suggest that magnocellular LSF processing of a human face may be the initial visual cue used to rapidly and automatically detect fear, but that this cue functions atypically in those with high autistic tendency.

Measurement of cortical functional activation in awake mice using two-photon microscopy and a novel pO2-sensitive probe(Conference Presentation)

NASA Astrophysics Data System (ADS)

Sencan, Ikbal; Esipova, Tatiana V.; Kilic, Kivilcim; Li, Baoqiang; Desjardins, Michèle; Yaseen, Mohammad A.; Wang, Hui; Jaswal, Rajeshwer S.; Kura, Sreekanth; Fu, Buyin; Boas, David A.; Devor, Anna; Sakadžić, Sava; Vinogradov, Sergei A.

2017-02-01

We characterized cortical microvascular PO2 and blood flow changes in response to whisker stimulation in awake mice. The measurements were performed by combining two-photon microscopy imaging of the cortical oxygenation and optical coherence tomography imaging of the cerebral blood flow. In order to perform fast spatio-temporally resolved measurements of PO2, we used a newly-developed oxygen-sensitive probe PtG-2P, which has significantly higher brightness than the established two-photon-enhanced oxygen sensor PtP-C343. We characterized the performance of the new probe in vivo and mapped the amplitudes and shapes (e.g. initial dip, overshoot, and post stimulus undershoot) of the PO2 changes as a function of the vessel type (e.g., arterioles, capillaries, and venules) and a distance from the activation center. The measurements in the awake mice are not affected by the confounding factors of anesthesia on the animal physiology, including the level of cerebral metabolism and the amplitude and speed of neuronal and vascular responses. Our results will help to understand changes in oxygenation and blood flow on the cortical microvascular scale, will lead to improved understanding of the cerebral physiology, pathophysiology and will improve quantitative interpretation of fMRI signals.

[Relationships between electrophysiological characteristic of speech evoked auditory brainstem response and Mandarin monosyllable discriminative ability at different hearing impairment].

PubMed

Fu, Q Y; Liang, Y; Zou, A; Wang, T; Zhao, X D; Wan, J

2016-04-07

To investigate the relationships between electrophysiological characteristic of speech evoked auditory brainstem response(s-ABR) and Mandarin phonetically balanced maximum(PBmax) at different hearing impairment, so as to provide more clues for the mechanism of speech cognitive behavior. Forty-one ears in 41 normal hearing adults(NH), thirty ears in 30 conductive hearing loss patients(CHL) and twenty-seven ears in 27 sensorineural hearing loss patients(SNHL) were included in present study. The speech discrimination scores were obtained by Mandarin phonemic-balanced monosyllable lists via speech audiometric software. Their s-ABRs were recorded with speech syllables /da/ with the intensity of phonetically balanced maximum(PBmax). The electrophysiological characteristic of s-ABR, as well as the relationships between PBmax and s-ABR parameters including latency in time domain, fundamental frequency(F0) and first formant(F1) in frequency domain were analyzed statistically. All subjects completed good speech perception tests and PBmax of CHL and SNHL had no significant difference (P>0.05), but both significantly less than that of NH (P<0.05). While divided the subjects into three groups by 90%

Target and beam-target spin asymmetries in exclusive pion electroproduction for Q2>1 GeV2 . I. e p →e π+n

NASA Astrophysics Data System (ADS)

Bosted, P. E.; Amaryan, M. J.; Anefalos Pereira, S.; Avakian, H.; Badui, R. A.; Ball, J.; Baltzell, N. A.; Battaglieri, M.; Batourine, V.; Bedlinskiy, I.; Biselli, A. S.; Briscoe, W. J.; Bültmann, S.; Burkert, V. D.; Carman, D. S.; Celentano, A.; Chandavar, S.; Charles, G.; Ciullo, G.; Clark, L.; Colaneri, L.; Cole, P. L.; Contalbrigo, M.; Crede, V.; D'Angelo, A.; De Vita, R.; Deur, A.; De Sanctis, E.; Djalali, C.; Dupre, R.; Egiyan, H.; El Alaoui, A.; El Fassi, L.; Elouadrhiri, L.; Eugenio, P.; Fanchini, E.; Fedotov, G.; Filippi, A.; Fleming, J. A.; Forest, T.; Fradi, A.; Gevorgyan, N.; Ghandilyan, Y.; Gilfoyle, G. P.; Girod, F. X.; Gleason, C.; Gohn, W.; Golovatch, E.; Gothe, R. W.; Griffioen, K. A.; Guidal, M.; Hakobyan, H.; Hattawy, M.; Hicks, K.; Holtrop, M.; Hughes, S. M.; Ilieva, Y.; Ireland, D. G.; Ishkhanov, B. S.; Isupov, E. L.; Jiang, H.; Jo, H. S.; Joo, K.; Joosten, S.; Khachatryan, G.; Khandaker, M.; Kim, A.; Kim, W.; Klein, F. J.; Koirala, S.; Kubarovsky, V.; Kuhn, S. E.; Lanza, L.; Net, L. A.; Lenisa, P.; Livingston, K.; MacGregor, I. J. D.; McCracken, M. E.; McKinnon, B.; Meyer, C. A.; Mirazita, M.; Mokeev, V. I.; Montgomery, R. A.; Munevar, E.; Munoz Camacho, C.; Murdoch, G.; Nadel-Turonski, P.; Niccolai, S.; Osipenko, M.; Ostrovidov, A. I.; Park, K.; Pasyuk, E.; Peng, P.; Phelps, W.; Pisano, S.; Pogorelko, O.; Price, J. W.; Prok, Y.; Protopopescu, D.; Puckett, A. J. R.; Raue, B. A.; Ripani, M.; Rosner, G.; Rossi, P.; Schumacher, R. A.; Seder, E.; Skorodumina, Iu.; Smith, G. D.; Sokhan, D.; Sparveris, N.; Stankovic, I.; Stepanyan, S.; Strakovsky, I. I.; Strauch, S.; Taiuti, M.; Tian, Ye; Torayev, B.; Ungaro, M.; Voskanyan, H.; Voutier, E.; Walford, N. K.; Wei, X.; Weinstein, L. B.; Zachariou, N.; Zhang, J.; Zhao, Z. W.; Zonta, I.; CLAS Collaboration

2017-03-01

Beam-target double-spin asymmetries and target single-spin asymmetries were measured for the exclusive π+ electroproduction reaction γ*p →n π+ . The results were obtained from scattering of 6-GeV longitudinally polarized electrons off longitudinally polarized protons using the CEBAF Large Acceptance Spectrometer at Jefferson Laboratory. The kinematic range covered is 1.1

The effect of short-term training on cardinal and oblique orientation discrimination: an ERP study.

PubMed

Song, Yan; Sun, Li; Wang, You; Zhang, Xuemin; Kang, Jing; Ma, Xiaoli; Yang, Bin; Guan, Yijie; Ding, Yulong

2010-03-01

The adult brain shows remarkable plasticity, as demonstrated by the improvement in most visual discrimination tasks after intensive practice. However, previous studies have demonstrated that practice improved the discrimination only around oblique orientations, while performance around cardinal orientations (vertical or horizontal orientations) remained stable despite extensive training. The two experiments described here used event-related potentials (ERPs) to investigate the neural substrates underlying different training effects in the two kinds of orientation. Event-related potentials were recorded from subjects when they were trained with a grating orientation discrimination task. Psychophysical threshold measurements were performed before and after the training. For oblique gratings, psychophysical thresholds decreased significantly across training sessions. ERPs showed larger P2 and P3 amplitudes and smaller N1 amplitudes over the parietal/occipital areas with more practice. In line with the psychophysical thresholds, the training effect on the P2 and P3 was specific to stimulus orientation. However, the N1 effect was generalized over differently oriented gratings stimuli. For cardinally oriented gratings, no significant changes were found in the psychophysical thresholds during the training. ERPs still showed similar generalized N1 effect as the oblique gratings. However, the amplitudes of P2 and P3 were unchanged during the whole training. Compared with cardinal orientations, more visual processing stages and later ERP components were involved in the training of oblique orientation discrimination. These results contribute to understanding the neural basis of the asymmetry between cardinal and oblique orientation training effects. Copyright 2009 Elsevier B.V. All rights reserved.

Electrophysiological correlates of target eccentricity in texture segmentation.

PubMed

Schaffer, Susann; Schubö, Anna; Meinecke, Cristina

2011-06-01

Event-related potentials and behavioural performance as a function of target eccentricity were measured while subjects performed a texture segmentation task. Fit-of-structures, i.e. easiness of target detection was varied: in Experiment 1, a texture with peripheral fit (easier detection of peripheral presented targets) and in Experiment 2, a texture with foveal fit (easier detection of foveal presented targets) was used. In the two experiments, the N2p was sensitive to target eccentricity showing larger amplitudes for foveal targets compared to peripheral targets, and at the foveal position, a reversal of the N2p differential amplitude effect was found. The anterior P2 seemed sensitive to the easiness of target detection. In both experiments the N2pc varied as a function of eccentricity. However, the P3 was neither sensitive to target eccentricity nor to the fit-of-structures. Results show the existence of a P2/N2 complex (Potts and Tucker, 2001) indicating executive functions located in the anterior cortex and perceptual processes located in the posterior cortex. Furthermore, the N2p might indicate the existence of a foveal vs. peripheral subsystem in visual processing. 2011 Elsevier B.V. All rights reserved.

Experimental study of the P11(1440) and D13(1520) resonances from the CLAS data on ep→e'π+π-p'

NASA Astrophysics Data System (ADS)

Mokeev, V. I.; Burkert, V. D.; Elouadrhiri, L.; Fedotov, G. V.; Golovatch, E. N.; Gothe, R. W.; Ishkhanov, B. S.; Isupov, E. L.; Adhikari, K. P.; Aghasyan, M.; Anghinolfi, M.; Avakian, H.; Baghdasaryan, H.; Ball, J.; Baltzell, N. A.; Battaglieri, M.; Batourine, V.; Bedlinskiy, I.; Biselli, A. S.; Bookwalter, C.; Boiarinov, S.; Briscoe, W. J.; Brooks, W. K.; Carman, D. S.; Celentano, A.; Charles, G.; Cole, P. L.; Contalbrigo, M.; Crede, V.; D'Angelo, A.; Daniel, A.; Dashyan, N.; De Vita, R.; De Sanctis, E.; Deur, A.; Djalali, C.; Doughty, D.; Dupre, R.; El Alaoui, A.; Eugenio, P.; Fegan, S.; Fradi, A.; Giovanetti, K. L.; Girod, F. X.; Gohn, W.; Graham, L.; Griffioen, K. A.; Guegan, B.; Guidal, M.; Guo, L.; Hafidi, K.; Hakobyan, H.; Hanretty, C.; Hicks, K.; Ho, D.; Holtrop, M.; Ilieva, Y.; Ireland, D. G.; Jo, H. S.; Joo, K.; Keller, D.; Khandaker, M.; Khetarpal, P.; Kim, A.; Kim, W.; Klein, A.; Klein, F. J.; Koirala, S.; Kubarovsky, A.; Kubarovsky, V.; Kuleshov, S. V.; Kvaltine, N. D.; Livingston, K.; Lu, H. Y.; MacGregor, I. J. D.; Mao, Y.; Markov, N.; Martinez, D.; Mayer, M.; McKinnon, B.; Meyer, C. A.; Mineeva, T.; Mirazita, M.; Moutarde, H.; Munevar, E.; Nadel-Turonski, P.; Nepali, C. S.; Ostrovidov, A. I.; Pappalardo, L. L.; Paremuzyan, R.; Park, K.; Park, S.; Pasyuk, E.; Pereira, S. Anefalos; Pisano, S.; Pogorelko, O.; Pozdniakov, S.; Price, J. W.; Procureur, S.; Protopopescu, D.; Raue, B. A.; Ricco, G.; Rimal, D.; Ripani, M.; Rosner, G.; Rossi, P.; Sabatié, F.; Saini, M. S.; Salgado, C.; Schott, D.; Schumacher, R. A.; Seder, E.; Seraydaryan, H.; Sharabian, Y. G.; Smith, G. D.; Smith, L. C.; Sober, D. I.; Sokhan, D.; Stepanyan, S.; Stepanyan, S. S.; Stoler, P.; Strakovsky, I. I.; Strauch, S.; Tang, W.; Taylor, C. E.; Tian, Ye; Tkachenko, S.; Trivedi, A.; Ungaro, M.; Vineyard, M. F.; Voskanyan, H.; Voutier, E.; Walford, N. K.; Wood, M. H.; Zachariou, N.; Zhao, Z. W.; Zonta, I.

2012-09-01

The transition helicity amplitudes from the proton ground state to the P11(1440) and D13(1520) excited states (γvpN* electrocouplings) were determined from the analysis of nine independent one-fold differential π+π-p electroproduction cross sections off a proton target, taken with CLAS at photon virtualities of 0.25

A statistical study of gyro-averaging effects in a reduced model of drift-wave transport

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fonseca, Julio; Del-Castillo-Negrete, Diego B.; Sokolov, Igor M.

2016-08-25

Here, a statistical study of finite Larmor radius (FLR) effects on transport driven by electrostatic driftwaves is presented. The study is based on a reduced discrete Hamiltonian dynamical system known as the gyro-averaged standard map (GSM). In this system, FLR effects are incorporated through the gyro-averaging of a simplified weak-turbulence model of electrostatic fluctuations. Formally, the GSM is a modified version of the standard map in which the perturbation amplitude, K 0, becomes K 0J 0(more » $$\\hat{p}$$), where J 0 is the zeroth-order Bessel function and $$\\hat{p}$$ s the Larmor radius. Assuming a Maxwellian probability density function (pdf) for $$\\hat{p}$$ , we compute analytically and numerically the pdf and the cumulative distribution function of the effective drift-wave perturba- tion amplitude K 0J 0($$\\hat{p}$$). Using these results, we compute the probability of loss of confinement (i.e., global chaos), P c provides an upper bound for the escape rate, and that P t rovides a good estimate of the particle trapping rate. Lastly. the analytical results are compared with direct numerical Monte-Carlo simulations of particle transport.« less

From cognitive motor preparation to visual processing: The benefits of childhood fitness to brain health.

PubMed

Berchicci, M; Pontifex, M B; Drollette, E S; Pesce, C; Hillman, C H; Di Russo, F

2015-07-09

The association between a fit body and a fit brain in children has led to a rise of behavioral and neuroscientific research. Yet, the relation of cardiorespiratory fitness on premotor neurocognitive preparation with early visual processing has received little attention. Here, 41 healthy, lower and higher fit preadolescent children were administered a modified version of the Eriksen flanker task while electroencephalography (EEG) and behavioral measures were recorded. Event-related potentials (ERPs) locked to the stimulus onset with an earlier than usual baseline (-900/-800 ms) allowed investigation of both the usual post-stimulus (i.e., the P1, N1 and P2) as well as the pre-stimulus ERP components, such as the Bereitschaftspotential (BP) and the prefrontal negativity (pN component). At the behavioral level, aerobic fitness was associated response accuracy, with higher fit children being more accurate than lower fit children. Fitness-related differences selectively emerged at prefrontal brain regions during response preparation, with larger pN amplitude for higher than lower fit children, and at early perceptual stages after stimulus onset, with larger P1 and N1 amplitudes in higher relative to lower fit children. Collectively, the results suggest that the benefits of being aerobically fit appear at the stage of cognitive preparation prior to stimulus presentation and the behavioral response during the performance of a task that challenges cognitive control. Further, it is likely that enhanced activity in prefrontal brain areas may improve cognitive control of visuo-motor tasks, allowing for stronger proactive inhibition and larger early allocation of selective attention resources on relevant external stimuli. Copyright © 2015 IBRO. Published by Elsevier Ltd. All rights reserved.

Sex differences and emotion regulation: an event-related potential study.

PubMed

Gardener, Elyse K T; Carr, Andrea R; Macgregor, Amy; Felmingham, Kim L

2013-01-01

Difficulties in emotion regulation have been implicated as a potential mechanism underlying anxiety and mood disorders. It is possible that sex differences in emotion regulation may contribute towards the heightened female prevalence for these disorders. Previous fMRI studies of sex differences in emotion regulation have shown mixed results, possibly due to difficulties in discriminating the component processes of early emotional reactivity and emotion regulation. The present study used event-related potentials (ERPs) to examine sex differences in N1 and N2 components (reflecting early emotional reactivity) and P3 and LPP components (reflecting emotion regulation). N1, N2, P3, and LPP were recorded from 20 men and 23 women who were instructed to "increase," "decrease," and "maintain" their emotional response during passive viewing of negative images. Results indicated that women had significantly greater N1 and N2 amplitudes (reflecting early emotional reactivity) to negative stimuli than men, supporting a female negativity bias. LPP amplitudes increased to the "increase" instruction, and women displayed greater LPP amplitudes than men to the "increase" instruction. There were no differences to the "decrease" instruction in women or men. These findings confirm predictions of the female negativity bias hypothesis and suggest that women have greater up-regulation of emotional responses to negative stimuli. This finding is highly significant in light of the female vulnerability for developing anxiety disorders.

The Clinical Utility of Vestibular Evoked Myogenic Potentials in Patients of Benign Paroxysmal Positional Vertigo.

PubMed

Sreenivasan, Anuprasad; Sivaraman, Ganesan; Parida, Pradiptata Kumar; Alexander, Arun; Saxena, Sunil Kumar; Suria, Gopalakrishnan

2015-06-01

Vestibular Evoked Myogenic Potentials (VEMP) is an emerging tool to diagnose Benign Paroxysmal Positional Vertigo (BPPV). The clinical utility of VEMP has been reported only in small accord in Indian literature. To study the latency and amplitude of VEMP in patients with BPPV and compare it with that of normal subjects. The study included two groups. Group one (control group) were 18 normal subjects. Group two (test group) were 15 subjects with unilateral BPPV. Those subjects who fulfilled the selection criteria based on case history and audiological assessment were taken for the VEMP recording. The VEMP response consist of positive and negative successive waves (pI-nI), with latency values in adults about 13 and 23 milliseconds respectively. Data was analysed using Statistical Package for Social Sciences (SPSS) version 12 (Chicago, IL, USA). Unpaired t-test was employed to measure the statistical difference between control group and test group. The difference in n23 and the peak to peak amplitude between the ipsilateral and contralateral ears of the test group were statistically significant, whereas such a difference in the p13 latency turned out to be statistically insignificant. It should be noted that, out of 15 patients in the test group, five patients showed only artifact tracer recordings in both the ears which is considered as no response. The heterogeneity of the results extended from absence of VEMP to prolongation of both p13, n23; prolongation of p13 alone; and even side to side variations. Absent response from the ipsilateral ear, prolonged latency of n23 and decreased peak to peak amplitude (p13, n23), indicates the disease pathology. However, large sample size is required to draw further conclusions and to consolidate the usage of VEMP in the diagnosis of BPPV.

Sexual dysfunction in pre-menopausal diabetic women: clinical, metabolic, psychological, cardiovascular, and neurophysiologic correlates.

PubMed

Cortelazzi, Donatella; Marconi, Annamaria; Guazzi, Marco; Cristina, Maurizio; Zecchini, Barbara; Veronelli, Annamaria; Cattalini, Claudio; Innocenti, Alessandro; Bosco, Giovanna; Pontiroli, Antonio E

2013-12-01

An increased prevalence of female sexual dysfunction (FSD) has been reported in women with diabetes mellitus (DM). Our aim was to evaluate correlates (psychological, cardiovascular, and neurophysiologic) of FSD in DM women without chronic diabetic complications. Female Sexual Function Index (FSFI), Beck Depression Inventory (BDI), Michigan Diabetic Neuropathy Index (DNI), and the symptoms of diabetic neuropathy (SDN) questionnaires, metabolic variables, endothelial vascular function (flow-mediated dilation, FMD), echocardiography, and electromyography were studied. 109 pre-menopausal women (18-50 years) [48 with DM (14 type 1 DM, 34 type 2 DM, duration 12.6 ± 1.91 years), and 61 healthy women] received the above questionnaires; physical activity, smoking habits, parity, BMI, waist circumference, HOMA-IR index, fibrinogen, cholesterol (total, HDL, LDL), triglycerides, HbA1c, high-sensitivity C-reactive protein, total testosterone, and estradiol were measured; echocardiography, assessment of intima-media thickness (IMT), FMD, ECG (heart rate and Qtc, indexes of sympathetic activity), and electromyography were performed. FSFI total score and score for arousal, lubrication, and orgasm domains were lower in DM women than in controls (P < 0.05); DM women had higher BDI, Doppler A wave peak velocity, DNI, and SDN score (P < 0.001 to P < 0.04). Doppler E wave peak velocity, peroneal, posterior tibial and sural nerves conduction velocity and amplitude were lower in diabetic women than in controls (P < 0.05 to P < 0.001). FSFI score was positively correlated with physical activity, Doppler E wave peak velocity, and peroneal nerve amplitude and negatively with BDI, parity, IMT, SDN, and HbA1c (P < 0.05 to P < 0.001). At stepwise regression, SDN score (negatively) and Doppler E wave peak velocity (positively) predicted FSFI score (r = 507, P < 0.001). In conclusion, cardiovascular and neurological impairments are associated with FSD in diabetic women. Follow-up studies are required to evaluate sexual dysfunction as a risk factor for future cardiovascular or neurological events.

Auditory Event-Related Potentials (ERPs) in Audiovisual Speech Perception

ERIC Educational Resources Information Center

Pilling, Michael

2009-01-01

Purpose: It has recently been reported (e.g., V. van Wassenhove, K. W. Grant, & D. Poeppel, 2005) that audiovisual (AV) presented speech is associated with an N1/P2 auditory event-related potential (ERP) response that is lower in peak amplitude compared with the responses associated with auditory only (AO) speech. This effect was replicated.…

Longitudinal differences and inter-annual variations of zonal wind in the tropical stratosphere and troposphere

NASA Astrophysics Data System (ADS)

Reddy, C. A.; Raghava Reddi, C.

1986-12-01

A quantitative assessment has been made of the longitude-dependent differences and the interannual variations of the zonal wind components in the equatorial stratosphere and troposphere, from the analysis of rocket and balloon data for 1979 and 1980 for three stations near ±8.5° latitude (Ascension Island at 14.4°W, Thumba at 76.9°E and Kwajalein at 67.7°E) and two stations near 21.5° latitude (Barking Sands at 159.6°W and Balasore at 86.9°E). The longitude-dependent differences are found to be about 10-20 m s -1 (amounting to 50-200% in some cases) for the semi-annual oscillation (SAO) and the annual oscillation (AO) amplitudes, depending upon the altitude and latitude. Inter-annual variations of about 10 m s -1 also exist in both oscillations. The phase of the SAO exhibits an almost 180° shift at Kwajalein compared to that at the other two stations near 8.5°, while the phase of the AO is independent of longitude, in the stratosphere. The amplitude and phase of the quasi-biennial oscillation (QBO) are found to be almost independent of longitude in the 18-38 km range, but above 40 km height the QBO amplitude and phase have different values in different longitude sectors for the three stations near ±8.5° latitude. The mean zonal wind shows no change from 1979 to 1980, but in the troposphere at 8.5° latitude strong easterlies prevail in the Indian zone, in contrast to the westerlies at the Atlantic and Pacific stations.

Mechanisms of quadriceps muscle weakness in knee joint osteoarthritis: the effects of prolonged vibration on torque and muscle activation in osteoarthritic and healthy control subjects.

PubMed

Rice, David A; McNair, Peter J; Lewis, Gwyn N

2011-01-01

A consequence of knee joint osteoarthritis (OA) is an inability to fully activate the quadriceps muscles, a problem termed arthrogenic muscle inhibition (AMI). AMI leads to marked quadriceps weakness that impairs physical function and may hasten disease progression. The purpose of the present study was to determine whether γ-loop dysfunction contributes to AMI in people with knee joint OA. Fifteen subjects with knee joint OA and 15 controls with no history of knee joint pathology participated in this study. Quadriceps and hamstrings peak isometric torque (Nm) and electromyography (EMG) amplitude were collected before and after 20 minutes of 50 Hz vibration applied to the infrapatellar tendon. Between-group differences in pre-vibration torque were analysed using a one-way analysis of covariance, with age, gender and body mass (kg) as the covariates. If the γ-loop is intact, vibration should decrease torque and EMG levels in the target muscle; if dysfunctional, then torque and EMG levels should not change following vibration. One-sample t tests were thus undertaken to analyse whether percentage changes in torque and EMG differed from zero after vibration in each group. In addition, analyses of covariance were utilised to analyse between-group differences in the percentage changes in torque and EMG following vibration. Pre-vibration quadriceps torque was significantly lower in the OA group compared with the control group (P = 0.005). Following tendon vibration, quadriceps torque (P < 0.001) and EMG amplitude (P ≤0.001) decreased significantly in the control group but did not change in the OA group (all P > 0.299). Hamstrings torque and EMG amplitude were unchanged in both groups (all P > 0.204). The vibration-induced changes in quadriceps torque and EMG were significantly different between the OA and control groups (all P < 0.011). No between-group differences were observed for the change in hamstrings torque or EMG (all P > 0.554). γ-loop dysfunction may contribute to AMI in individuals with knee joint OA, partially explaining the marked quadriceps weakness and atrophy that is often observed in this population.

Mechanisms of quadriceps muscle weakness in knee joint osteoarthritis: the effects of prolonged vibration on torque and muscle activation in osteoarthritic and healthy control subjects

PubMed Central

2011-01-01

Introduction A consequence of knee joint osteoarthritis (OA) is an inability to fully activate the quadriceps muscles, a problem termed arthrogenic muscle inhibition (AMI). AMI leads to marked quadriceps weakness that impairs physical function and may hasten disease progression. The purpose of the present study was to determine whether γ-loop dysfunction contributes to AMI in people with knee joint OA. Methods Fifteen subjects with knee joint OA and 15 controls with no history of knee joint pathology participated in this study. Quadriceps and hamstrings peak isometric torque (Nm) and electromyography (EMG) amplitude were collected before and after 20 minutes of 50 Hz vibration applied to the infrapatellar tendon. Between-group differences in pre-vibration torque were analysed using a one-way analysis of covariance, with age, gender and body mass (kg) as the covariates. If the γ-loop is intact, vibration should decrease torque and EMG levels in the target muscle; if dysfunctional, then torque and EMG levels should not change following vibration. One-sample t tests were thus undertaken to analyse whether percentage changes in torque and EMG differed from zero after vibration in each group. In addition, analyses of covariance were utilised to analyse between-group differences in the percentage changes in torque and EMG following vibration. Results Pre-vibration quadriceps torque was significantly lower in the OA group compared with the control group (P = 0.005). Following tendon vibration, quadriceps torque (P < 0.001) and EMG amplitude (P ≤0.001) decreased significantly in the control group but did not change in the OA group (all P > 0.299). Hamstrings torque and EMG amplitude were unchanged in both groups (all P > 0.204). The vibration-induced changes in quadriceps torque and EMG were significantly different between the OA and control groups (all P < 0.011). No between-group differences were observed for the change in hamstrings torque or EMG (all P > 0.554). Conclusions γ-loop dysfunction may contribute to AMI in individuals with knee joint OA, partially explaining the marked quadriceps weakness and atrophy that is often observed in this population. PMID:21933392

Gravitational wave production from preheating: parameter dependence

DOE Office of Scientific and Technical Information (OSTI.GOV)

Figueroa, Daniel G.; Torrentí, Francisco, E-mail: daniel.figueroa@cern.ch, E-mail: f.torrenti@csic.es

Parametric resonance is among the most efficient phenomena generating gravitational waves (GWs) in the early Universe. The dynamics of parametric resonance, and hence of the GWs, depend exclusively on the resonance parameter q . The latter is determined by the properties of each scenario: the initial amplitude and potential curvature of the oscillating field, and its coupling to other species. Previous works have only studied the GW production for fixed value(s) of q . We present an analytical derivation of the GW amplitude dependence on q , valid for any scenario, which we confront against numerical results. By running latticemore » simulations in an expanding grid, we study for a wide range of q values, the production of GWs in post-inflationary preheating scenarios driven by parametric resonance. We present simple fits for the final amplitude and position of the local maxima in the GW spectrum. Our parametrization allows to predict the location and amplitude of the GW background today, for an arbitrary q . The GW signal can be rather large, as h {sup 2Ω}{sub GW}( f {sub p} ) ∼< 10{sup −11}, but it is always peaked at high frequencies f {sub p} ∼> 10{sup 7} Hz. We also discuss the case of spectator-field scenarios, where the oscillatory field can be e.g. a curvaton, or the Standard Model Higgs.« less

A comparative study of the effects of cone-plate and parallel-plate geometries on rheological properties under oscillatory shear flow

NASA Astrophysics Data System (ADS)

Song, Hyeong Yong; Salehiyan, Reza; Li, Xiaolei; Lee, Seung Hak; Hyun, Kyu

2017-11-01

In this study, the effects of cone-plate (C/P) and parallel-plate (P/P) geometries were investigated on the rheological properties of various complex fluids, e.g. single-phase (polymer melts and solutions) and multiphase systems (polymer blend and nanocomposite, and suspension). Small amplitude oscillatory shear (SAOS) tests were carried out to compare linear rheological responses while nonlinear responses were compared using large amplitude oscillatory shear (LAOS) tests at different frequencies. Moreover, Fourier-transform (FT)-rheology method was used to analyze the nonlinear responses under LAOS flow. Experimental results were compared with predictions obtained by single-point correction and shear rate correction. For all systems, SAOS data measured by C/P and P/P coincide with each other, but results showed discordance between C/P and P/P measurements in the nonlinear regime. For all systems except xanthan gum solutions, first-harmonic moduli were corrected using a single horizontal shift factor, whereas FT rheology-based nonlinear parameters ( I 3/1, I 5/1, Q 3, and Q 5) were corrected using vertical shift factors that are well predicted by single-point correction. Xanthan gum solutions exhibited anomalous corrections. Their first-harmonic Fourier moduli were superposed using a horizontal shift factor predicted by shear rate correction applicable to highly shear thinning fluids. The distinguished corrections were observed for FT rheology-based nonlinear parameters. I 3/1 and I 5/1 were superposed by horizontal shifts, while the other systems displayed vertical shifts of I 3/1 and I 5/1. Q 3 and Q 5 of xanthan gum solutions were corrected using both horizontal and vertical shift factors. In particular, the obtained vertical shift factors for Q 3 and Q 5 were twice as large as predictions made by single-point correction. Such larger values are rationalized by the definitions of Q 3 and Q 5. These results highlight the significance of horizontal shift corrections in nonlinear oscillatory shear data.

Changes in N1 and P3 components of the auditory event-related potentials in extroverts and introverts depending on the type of the task.

PubMed

Philipova, Dolja T

2008-01-01

The aim of the study was to examine the interconnection between N1 and P3 components of event-related potentials (ERP) and the personality type extraversion/introversion in two tasks with different conditions: mental and sensomotor. The hypothesis to test was that the difference in the information processing by extraverts and introverts depends on the task type. Twenty-six healthy middle-aged volunteers (13 extroverts, 13 introverts) were studied. The two groups were matched in gender, age and education. Electroencephalograms were recorded from Fz, Cz and Pz (10/20 system). Each subject participated in three series of 100 sound stimuli each (75 high--1200 Hz and 25 low--800 Hz, randomly presented)--a passive series, a series with a sensomotor task and a series with a mental task (counting of high tones). We found differences in the stimulus information processing between extraverts and introverts, most prominent in the series with tasks. The introverts showed shorter latency and lower amplitudes of N1 in the counting task and longer latency and higher amplitudes in sensomotor tasks than did the extraverts. The extroverts had higher P3 amplitudes in the series with tasks. The present study confirms the hypothesis that the personality type has an electrophysiological substrate, the type characteristics--extraversion/introversion influence the parameters of N1 and P3 components. The interconnection between the personality type and the processes of cortical activation depend on the type and requirements of the task.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bolton, Daniel R.; Briceno, Raul A.; Wilson, David J.

Here, we present a determination of the isovector,more » $P$-wave $$\\pi\\pi$$ scattering phase shift obtained by extrapolating recent lattice QCD results from the Hadron Spectrum Collaboration using $$m_\\pi =236$$ MeV. The finite volume spectra are described using extensions of L\\"uscher's method to determine the infinite volume Unitarized Chiral Perturbation Theory scattering amplitude. We exploit the pion mass dependence of this effective theory to obtain the scattering amplitude at $$m_\\pi= 140$$ MeV. The scattering phase shift is found to be in good agreement with experiment up to center of mass energies of 1.2 GeV. The analytic continuation of the scattering amplitude to the complex plane yields a $$\\rho$$-resonance pole at $$E_\\rho= \\left[755(2)(1)(^{20}_{02})-\\frac{i}{2}\\,129(3)(1)(^{7}_{1})\\right]~{\\rm MeV}$$. The techniques presented illustrate a possible pathway towards connecting lattice QCD observables of few-body, strongly interacting systems to experimentally accessible quantities.« less

Electroexcitation of nucleon resonances from CLAS data on single pion electroproduction

DOE Office of Scientific and Technical Information (OSTI.GOV)

Aznauryan, I. G.; Yerevan Physics Institute, 375036 Yerevan; Burkert, V. D.

2009-11-15

We present results on the electroexcitation of the low mass resonances {delta}(1232)P{sub 33}, N(1440)P{sub 11}, N(1520)D{sub 13}, and N(1535)S{sub 11} in a wide range of Q{sup 2}. The results were obtained in the comprehensive analysis of data from the Continuous Electron Beam Accelerator Facility (CEBAF) large acceptance spectrometer (CLAS) detector at the Thomas Jefferson National Accelerator Facility (JLab) on differential cross sections, longitudinally polarized beam asymmetries, and longitudinal target and beam-target asymmetries for {pi} electroproduction off the proton. The data were analyzed using two conceptually different approaches--fixed-t dispersion relations and a unitary isobar model--allowing us to draw conclusions on themore » model sensitivity of the obtained electrocoupling amplitudes. The amplitudes for the {delta}(1232)P{sub 33} show the importance of a meson-cloud contribution to quantitatively explain the magnetic dipole strength, as well as the electric and scalar quadrupole transitions. They do not show any tendency of approaching the pQCD regime for Q{sup 2}{<=}6 GeV{sup 2}. For the Roper resonance, N(1440)P{sub 11}, the data provide strong evidence that this state is a predominantly radial excitation of a three-quark (3q) ground state. Measured in pion electroproduction, the transverse helicity amplitude for the N(1535)S{sub 11} allowed us to obtain the branching ratios of this state to the {pi}N and {eta}N channels via comparison with the results extracted from {eta} electroproduction. The extensive CLAS data also enabled the extraction of the {gamma}*p{yields}N(1520)D{sub 13} and N(1535)S{sub 11} longitudinal helicity amplitudes with good precision. For the N(1535)S{sub 11}, these results became a challenge for quark models and may be indicative of large meson-cloud contributions or of representations of this state that differ from a 3q excitation. The transverse amplitudes for the N(1520)D{sub 13} clearly show the rapid changeover from helicity-3/2 dominance at the real photon point to helicity-1/2 dominance at Q{sup 2}>1 GeV{sup 2}, confirming a long-standing prediction of the constituent quark model.« less

An event-related potential investigation of spatial attention orientation in children trained with mental abacus calculation.

PubMed

Liu, Xiaoqin; Sun, Yanchao

2017-01-01

The objective of this study was to investigate the effects of long-term mental abacus calculation training (MACT) on children's spatial attention orientation. Fifteen children with intensive MACT (MACT group) and 15 children without MACT (non-MACT group) were selected. The two groups of children were matched in age, sex, handedness, and academic grade. The participants were tested with a Posner spatial cueing task while their neural activities were recorded with a 32-channel electroencephalogram system. The participants' behavior scores (reaction time and accuracy) as well as early components of event-related potential (ERP) during the tests were statistically analyzed. The behavioral scores showed no significant difference between the two groups of children, although the MACT group tended to have a shorter reaction time. The early ERP components showed that under valid cueing condition, the MACT group had significantly higher P1 amplitude [F(1, 28)=5.06, P<0.05, effective size=0.72] and lower N1 amplitude [F(1, 28)=6.05, P<0.05, effective size=0.82] in the occipital region compared with the non-MACT group. In the centrofrontal brain region, the MACT group had lower N1 amplitude [F(1, 28)=4.89, P<0.05, effect size=0.70] and longer N1 latency [F(1, 28)=6.26, P<0.05, effect size=0.80] than the non-MACT group. In particular, the MACT group also showed a higher centrofrontal P2 amplitude in the right hemisphere [F(1, 28)=4.82, P<0.05, effect size 0.81] compared with the left hemisphere and the middle location. MACT enhances the children's spatial attention orientation, which can be detected in the early components of ERP.

The influence of digital filter type, amplitude normalisation method, and co-contraction algorithm on clinically relevant surface electromyography data during clinical movement assessments.

PubMed

Devaprakash, Daniel; Weir, Gillian J; Dunne, James J; Alderson, Jacqueline A; Donnelly, Cyril J

2016-12-01

There is a large and growing body of surface electromyography (sEMG) research using laboratory-specific signal processing procedures (i.e., digital filter type and amplitude normalisation protocols) and data analyses methods (i.e., co-contraction algorithms) to acquire practically meaningful information from these data. As a result, the ability to compare sEMG results between studies is, and continues to be challenging. The aim of this study was to determine if digital filter type, amplitude normalisation method, and co-contraction algorithm could influence the practical or clinical interpretation of processed sEMG data. Sixteen elite female athletes were recruited. During data collection, sEMG data was recorded from nine lower limb muscles while completing a series of calibration and clinical movement assessment trials (running and sidestepping). Three analyses were conducted: (1) signal processing with two different digital filter types (Butterworth or critically damped), (2) three amplitude normalisation methods, and (3) three co-contraction ratio algorithms. Results showed the choice of digital filter did not influence the clinical interpretation of sEMG; however, choice of amplitude normalisation method and co-contraction algorithm did influence the clinical interpretation of the running and sidestepping task. Care is recommended when choosing amplitude normalisation method and co-contraction algorithms if researchers/clinicians are interested in comparing sEMG data between studies. Copyright © 2016 Elsevier Ltd. All rights reserved.

Terahertz excitation spectra of InP single crystals

NASA Astrophysics Data System (ADS)

Norkus, R.; Arlauskas, A.; Krotkus, A.

2018-07-01

Investigation of terahertz (THz) pulse generation from semi-insulating and n-type InP crystals surfaces is presented in this letter. In order to determine energy separation between the main and subsidiary conduction band valleys, THz pulse amplitude dependences on the photoexcitation wavelength (in a range of 410–950 nm) were measured. These dependences had a clear maximum at ∼540 nm, from which the inter-valley energy separation in the conduction band of InP as equal to 0.75 eV was determined. Moreover, THz generation mechanisms at laser excited surfaces of InP were investigated by additionally analyzing the azimuthal angle dependences of the emitted THz signal amplitude and power. It has been shown that the main physical mechanism of the surface THz emission in this material is the spatial separation of photoexcited electrons and holes, which can also lead to a symmetry similar to the second order optical nonlinearity. Photocurrent surge in the surface electric field can also contribute to the THz emission from a semi-insulating crystal illuminated by optical pulses with the wavelengths close to the absorption edge.

[Research on the stability of teaching robots of rotation-traction manipulation].

PubMed

Feng, Min-Shan; Zhu, Li-Guo; Wang, Shang-Quan; Yu, Jie; Chen, Ming; Li, Ling-Hui; Wei, Xu

2017-03-25

To evaluate the stability of teaching robot of rotation-traction manipulation. Operators were required to get the hang of rotation-traction manipulation and had clinical experience for over 5 years. The examination and data processing of the ten operators in our research were collected by the teaching robot of rotation-traction manipulation. Traction, pulling force, maximum force, pulling time, rotational amplitude and pitch range were recorded and compared for five times(G1, G2, G3, G4 and G5). The qualification rates were analyzed to evaluate the stability of teaching robot of rotation-traction manipulation. Nonconforming items were found in G1 and G2, for instance, pulling force( P =0.074), maximum force( P =0.264) and rotational amplitude ( P =0.531). There was no statistically difference. None nonconforming item was found in G3, G4 and G5. All data were processed by SPSS and One-way ANOVA was used to analysis. Pulling force was found statistically different in G1, compared with G4 and G5( P =0.015, P =0.006). Maximum force was found statistically different in G1, compared with G4 and G5 ( P =0.021, P =0.012). None differences were found in other comparisons ( P >0.05). The teaching robot of rotation-traction manipulation used in our research could provide objective and quantitative indices and was considered to be an effective tool of assessing the rotation-traction manipulation.

Lower regulatory frequency for postural control in patients with fibromyalgia and chronic fatigue syndrome.

PubMed

Rasouli, Omid; Vasseljen, Ottar; Fors, Egil A; Lorås, Håvard W; Stensdotter, Ann-Katrin

2018-01-01

As many similar symptoms are reported in fibromyalgia (FM) and chronic fatigue syndrome (CFS), underlying defcits may potentially also be similar. Postural disequilibrium reported in both conditions may thus be explained by similar deviations in postural control strategies. 75 females (25/group FM, CFS and control, age 19-49 years) performed 60 s of quiet standing on a force platform in each of three conditions: 1) firm surface with vision, 2) firm surface without vision and, 3) compliant surface with vision. Migration of center of pressure was decomposed into a slow and a fast component denoting postural sway and lateral forces controlling postural sway, analyzed in the time and frequency domains. Main effects of group for the antero-posterior (AP) and medio-lateral (ML) directions showed that patients displayed larger amplitudes (AP, p = 0.002; ML, p = 0.021) and lower frequencies (AP, p < 0.001; ML, p < 0.001) for the slow component, as well as for the fast component (amplitudes: AP, p = 0.010; ML, p = 0.001 and frequencies: AP, p = 0.001; ML, p = 0.029) compared to controls. Post hoc analyses showed no significant differences between patient groups. In conclusion, both the CFS- and the FM-group differed from the control group. Larger postural sway and insufficient control was found in patients compared to controls, with no significant differences between the two patient groups.

Lower regulatory frequency for postural control in patients with fibromyalgia and chronic fatigue syndrome

PubMed Central

Rasouli, Omid; Vasseljen, Ottar; Fors, Egil A.; Lorås, Håvard W.

2018-01-01

As many similar symptoms are reported in fibromyalgia (FM) and chronic fatigue syndrome (CFS), underlying defcits may potentially also be similar. Postural disequilibrium reported in both conditions may thus be explained by similar deviations in postural control strategies. 75 females (25/group FM, CFS and control, age 19–49 years) performed 60 s of quiet standing on a force platform in each of three conditions: 1) firm surface with vision, 2) firm surface without vision and, 3) compliant surface with vision. Migration of center of pressure was decomposed into a slow and a fast component denoting postural sway and lateral forces controlling postural sway, analyzed in the time and frequency domains. Main effects of group for the antero-posterior (AP) and medio-lateral (ML) directions showed that patients displayed larger amplitudes (AP, p = 0.002; ML, p = 0.021) and lower frequencies (AP, p < 0.001; ML, p < 0.001) for the slow component, as well as for the fast component (amplitudes: AP, p = 0.010; ML, p = 0.001 and frequencies: AP, p = 0.001; ML, p = 0.029) compared to controls. Post hoc analyses showed no significant differences between patient groups. In conclusion, both the CFS- and the FM-group differed from the control group. Larger postural sway and insufficient control was found in patients compared to controls, with no significant differences between the two patient groups. PMID:29617424

Selection of higher eigenmode amplitude based on dissipated power and virial contrast in bimodal atomic force microscopy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Diaz, Alfredo J.; Eslami, Babak; López-Guerra, Enrique A.

2014-09-14

This paper explores the effect of the amplitude ratio of the higher to the fundamental eigenmode in bimodal atomic force microscopy (AFM) on the phase contrast and the dissipated power contrast of the higher eigenmode. We explore the optimization of the amplitude ratio in order to maximize the type of contrast that is most relevant to the particular study. Specifically, we show that the trends in the contrast range behave differently for different quantities, especially the dissipated power and the phase, with the former being more meaningful than the latter (a similar analysis can be carried out using the virial,more » for which we also provide a brief example). Our work is based on numerical simulations using two different conservative-dissipative tip-sample models, including the standard linear solid and the combination of a dissipation coefficient with a conservative model, as well as experimental images of thin film Nafion{sup ®} proton exchange polymers. We focus on the original bimodal AFM method, where the higher eigenmode is driven with constant amplitude and frequency (i.e., in “open loop”).« less

Influence of visual angle on pattern reversal visual evoked potentials

PubMed Central

Kothari, Ruchi; Singh, Smita; Singh, Ramji; Shukla, A. K.; Bokariya, Pradeep

2014-01-01

Purpose: The aim of this study was to find whether the visual evoked potential (VEP) latencies and amplitude are altered with different visual angles in healthy adult volunteers or not and to determine the visual angle which is the optimum and most appropriate among a wide range of check sizes for the reliable interpretation of pattern reversal VEPs (PRVEPs). Materials and Methods: The present study was conducted on 40 healthy volunteers. The subjects were divided into two groups. One group consisted of 20 individuals (nine males and 11 females) in the age range of 25-57 years and they were exposed to checks subtending a visual angle of 90, 120, and 180 minutes of arc. Another group comprised of 20 individuals (10 males and 10 females) in the age range of 36-60 years and they were subjected to checks subtending a visual angle of 15, 30, and 120 minutes of arc. The stimulus configuration comprised of the transient pattern reversal method in which a black and white checker board is generated (full field) on a VEP Monitor by an Evoked Potential Recorder (RMS EMG. EPMARK II). The statistical analysis was done by One Way Analysis of Variance (ANOVA) using EPI INFO 6. Results: In Group I, the maximum (max.) P100 latency of 98.8 ± 4.7 and the max. P100 amplitude of 10.05 ± 3.1 μV was obtained with checks of 90 minutes. In Group II, the max. P100 latency of 105.19 ± 4.75 msec as well as the max. P100 amplitude of 8.23 ± 3.30 μV was obtained with 15 minutes. The min. P100 latency in both the groups was obtained with checks of 120 minutes while the min. P100 amplitude was obtained with 180 minutes. A statistically significant difference was derived between means of P100 latency for 15 and 30 minutes with reference to its value for 120 minutes and between the mean value of P100 amplitude for 120 minutes and that of 90 and 180 minutes. Conclusion: Altering the size of stimulus (visual angle) has an effect on the PRVEP parameters. Our study found that the 120 is the appropriate (and optimal) check size that can be used for accurate interpretation of PRVEPs. This will help in better assessment of the optic nerve function and integrity of anterior visual pathways. PMID:25378875

Muscle metabolic and neuromuscular determinants of fatigue during cycling in different exercise intensity domains

PubMed Central

Black, Matthew I.; Jones, Andrew M.; Blackwell, Jamie R.; Bailey, Stephen J.; Wylie, Lee J.; McDonagh, Sinead T. J.; Thompson, Christopher; Kelly, James; Sumners, Paul; Mileva, Katya N.; Bowtell, Joanna L.

2017-01-01

Lactate or gas exchange threshold (GET) and critical power (CP) are closely associated with human exercise performance. We tested the hypothesis that the limit of tolerance (Tlim) during cycle exercise performed within the exercise intensity domains demarcated by GET and CP is linked to discrete muscle metabolic and neuromuscular responses. Eleven men performed a ramp incremental exercise test, 4–5 severe-intensity (SEV; >CP) constant-work-rate (CWR) tests until Tlim, a heavy-intensity (HVY; GET) CWR test until Tlim, and a moderate-intensity (MOD; 0.05) muscle metabolic milieu (i.e., low pH and [PCr] and high [lactate]) was attained at Tlim (approximately 2–14 min) for all SEV exercise bouts. The muscle metabolic perturbation was greater at Tlim following SEV compared with HVY, and also following SEV and HVY compared with MOD (all P < 0.05). The normalized M-wave amplitude for the vastus lateralis (VL) muscle decreased to a similar extent following SEV (−38 ± 15%), HVY (−68 ± 24%), and MOD (−53 ± 29%), (P > 0.05). Neural drive to the VL increased during SEV (4 ± 4%; P < 0.05) but did not change during HVY or MOD (P > 0.05). During SEV and HVY, but not MOD, the rates of change in M-wave amplitude and neural drive were correlated with changes in muscle metabolic ([PCr], [lactate]) and blood ionic/acid-base status ([lactate], [K+]) (P < 0.05). The results of this study indicate that the metabolic and neuromuscular determinants of fatigue development differ according to the intensity domain in which the exercise is performed. NEW & NOTEWORTHY The gas exchange threshold and the critical power demarcate discrete exercise intensity domains. For the first time, we show that the limit of tolerance during whole-body exercise within these domains is characterized by distinct metabolic and neuromuscular responses. Fatigue development during exercise greater than critical power is associated with the attainment of consistent “limiting” values of muscle metabolites, whereas substrate availability and limitations to muscle activation may constrain performance at lower intensities. PMID:28008101

Elastic and Diffractive Scattering - Proceedings of the International Conference on Vth Blois Workshop

NASA Astrophysics Data System (ADS)

Kang, K.; Fried, H. M.; Tan, C.-I.

1994-02-01

The Table of Contents for the book is as follows: * Preface * `Overview' on Elastic Scattering and Total Cross-Sections * A Precise Measurement of the Real Part of the Elastic Scattering Amplitude at the {S bar{p}pS} * Luminosity Dependent Measurement of the p bar{p} Total Cross Section at √{s} = 541 GeV * Status of Fermilab E-710 * Luminosity-Independent Measurement of bar{p}p Elastic Scattering, Single Diffraction, Dissociation and Total Cross Section at √{s} = 546 and 1800 GeV * Phase Relations Revisited: A Challenge for SSC and LHC * Status of Near-Forward Elastic Scattering * bar{p}p Collisions at √{s} = 1.8 TeV: p, σt and B * p bar{p} Forward Scattering Parameters Results from Fermilab E760 * Photoproduction Results from H1 at HERA * Total and Jet Photoproduction Cross Sections at HERA and Fermilab * Minijet Model for High Energy γp Cross Sections * The Pomeron as Massive Gluons * Large N Theories with Glueball-like Spectra * Unitarity Relations for Gluonic Pomeron * The Donnachie-Landshoff Pomeron vs. QCD * The Odderon Intercept in Perturbative QCD * Theoret. and Phenomenol. Aspects of the Odderon * First Theorist's Gaze at HERA Data at Low xB * H1 Results for Structure Functions at Small x * Partial Photoproduction Cross Sections at √{s} ≈prox 180 GeV and First Results on F2 of the Proton from the ZEUS Experiment * Observation of a New Class of Events in Deep Inelastic Scattering * Jet Production in Muon-Proton and Muon-Nuclei Scattering at Fermilab-E665 * D0 Studies of Perturbative QCD * Large Rapidity Gaps and Single Diffraction Dissociation in High Energy pp and bar{p}p Collisions * Hadron and Reggeon Structure in High Energy Collisions * Monte Carlo Studies of Diffractive Processes in Deep Inelastic Scattering * Elastic Parton-Parton Amplitudes in Geometrical Models * Non-Perturbative QCD Calculations of High-Energy Observables * Effective Field Theory for Diffractive QCD Processes * High Energy Behavior of σtot, ρ, and B - Asymptotic Amplitude Analysis and a QCD-Inspired Analysis * Rapidity Gaps and Multiplicity Fluctuations * Branching Processes and Multi-Particle Production * High Energy Elastic Scattering and Nucleon as a Topological Soliton * The Behavior of Cross Sections at Very High Energies * The Pomeron and QCD with Many Light Quarks * Heterotic Pomeron: High Energy Hadronic Collisions in QCD * CDF Results on Electroweak Physics * DØ Results on Electroweak Physics * Search for the Top Quark and Other New Particles at DØ * Rapidity Gaps and Forward Physics at DØ * High Energy Asymptotics of Perturbative Multi-Color QCD * Rapidity Gaps in e+e- Collisions * Large Rapidity Gap, Jet Events at HERA: a PQCD Approach * High Energy Parton-Parton Elastic Scattering in QCD * Parton-Parton Elastic Scattering and Rapidity Gaps at Tevatron Energies * Hard Elastic Scattering * Hard Diffractive Processes * Three Successful Tests of Color Transparency and Nuclear Filtering * New KNO in QCD * A Chiral Condensate Search at the Tevatron * Cosmic Ray Evidences for Aligned High Energy Jets at Supertevatron Energy and Hard DDD * "New Hadronic State" Observed in Extremely High Energy Cosmic-Ray Interactions * Meson and Nucleon Form Factors in PQCD * Elastic Charge Form Factors for Pseudoscalar Mesons * The Ultimate Experiment * Search for Coherent Charm Production in 800 GeV/c Proton-Silicon Interactions * Chiral Quark Model and Hadron Scattering * Elastic Spin Experiments at UNK, Fermilab and SSC * Spin-Flip in Elastic and Diffractive Scattering * FNAL Polarized Beams and Spin Dependence at RHIC * Particle Tracking in the Close-to-Forward Region (η > 5.5) * Blois V: Experimental Summary * Blois V: Summary Talk * List of Participants

Anomalously strong observations of PKiKP/PcP amplitude ratios on a global scale

NASA Astrophysics Data System (ADS)

Waszek, Lauren; Deuss, Arwen

2015-07-01

The inner core boundary marks the phase transition between the solid inner core and the fluid outer core. As the site of inner core solidification, the boundary provides insight into the processes generating the seismic structures of the inner core. In particular, it may hold the key to understanding the previously observed hemispherical asymmetry in inner core seismic velocity, anisotropy, and attenuation. Here we use a large PKiKP-PcP amplitude ratio and travel time residual data set to investigate velocity and density contrast properties near the inner core boundary. Although hemispherical structure at the boundary has been proposed by previous inner core studies, we find no evidence for hemispheres in the amplitude ratios or travel time residuals. In addition, we find that the amplitude ratios are much larger than can be explained by variations in density contrast at the inner core boundary or core-mantle boundary. This indicates that PKiKP is primarily observed when it is anomalously large, due to focusing along its raypath. Using data in which PKiKP is not detected above the noise level, we calculate an upper estimate for the inner core boundary (ICB) density contrast of 1.2 kg m-3. The travel time residuals display large regional variations, which differ on long and short length scales. These regions may be explained by large-scale velocity variations in the F layer just above the inner core boundary, and/or small-scale topography of varying magnitude on the ICB, which also causes the large amplitudes. Such differences could arise from localized freezing and melting of the inner core.

Reliability of corneal dynamic scheimpflug analyser measurements in virgin and post-PRK eyes.

PubMed

Chen, Xiangjun; Stojanovic, Aleksandar; Hua, Yanjun; Eidet, Jon Roger; Hu, Di; Wang, Jingting; Utheim, Tor Paaske

2014-01-01

To determine the measurement reliability of CorVis ST, a dynamic Scheimpflug analyser, in virgin and post-photorefractive keratectomy (PRK) eyes and compare the results between these two groups. Forty virgin eyes and 42 post-PRK eyes underwent CorVis ST measurements performed by two technicians. Repeatability was evaluated by comparing three consecutive measurements by technician A. Reproducibility was determined by comparing the first measurement by technician A with one performed by technician B. Intraobserver and interobserver intraclass correlation coefficients (ICCs) were calculated. Univariate analysis of covariance (ANCOVA) was used to compare measured parameters between virgin and post-PRK eyes. The intraocular pressure (IOP), central corneal thickness (CCT) and 1st applanation time demonstrated good intraobserver repeatability and interobserver reproducibility (ICC ≧ 0.90) in virgin and post-PRK eyes. The deformation amplitude showed a good or close to good repeatability and reproducibility in both groups (ICC ≧ 0.88). The CCT correlated positively with 1st applanation time (r = 0.437 and 0.483, respectively, p<0.05) and negatively with deformation amplitude (r = -0.384 and -0.375, respectively, p<0.05) in both groups. Compared to post-PRK eyes, virgin eyes showed longer 1st applanation time (7.29 ± 0.21 vs. 6.96 ± 0.17 ms, p<0.05) and lower deformation amplitude (1.06 ± 0.07 vs. 1.17 ± 0.08 mm, p < 0.05). CorVis ST demonstrated reliable measurements for CCT, IOP, and 1st applanation time, as well as relatively reliable measurement for deformation amplitude in both virgin and post-PRK eyes. There were differences in 1st applanation time and deformation amplitude between virgin and post-PRK eyes, which may reflect corneal biomechanical changes occurring after the surgery in the latter.

Brain potentials predict substance abuse treatment completion in a prison sample.

PubMed

Fink, Brandi C; Steele, Vaughn R; Maurer, Michael J; Fede, Samantha J; Calhoun, Vince D; Kiehl, Kent A

2016-08-01

National estimates suggest that up to 80% of prison inmates meet diagnostic criteria for a substance use disorder. Because more substance abuse treatment while incarcerated is associated with better post-release outcomes, including a reduced risk of accidental overdose death, the stakes are high in developing novel predictors of substance abuse treatment completion in inmate populations. Using electroencephalography (EEG), this study investigated stimulus-locked ERP components elicited by distractor stimuli in three tasks (VO-Distinct, VO-Repeated, Go/NoGo) as a predictor of treatment discontinuation in a sample of male and female prison inmates. We predicted that those who discontinued treatment early would exhibit a less positive P3a amplitude elicited by distractor stimuli. Our predictions regarding ERP components were partially supported. Those who discontinued treatment early exhibited a less positive P3a amplitude and a less positive PC4 in the VO-D task. In the VO-R task, however, those who discontinued treatment early exhibited a more negative N200 amplitude rather than the hypothesized less positive P3a amplitude. The discontinuation group also displayed less positive PC4 amplitude. Surprisingly, there were no time-domain or principle component differences among the groups in the Go/NoGo task. Support Vector Machine (SVM) models of the three tasks accurately classified individuals who discontinued treatment with the best model accurately classifying 75% of inmates. PCA techniques were more sensitive in differentiating groups than the classic time-domain windowed approach. Our pattern of findings are consistent with the context-updating theory of P300 and may help identify subtypes of ultrahigh-risk substance abusers who need specialized treatment programs.

Hard exclusive pion electroproduction at backward angles with CLAS

DOE PAGES

Park, K.; Guidal, M.; Gothe, R. W.; ...

2018-03-09

We report on the first measurement of cross sections for exclusive deeply virtual pion electroproduction off the proton,more » $$e p \\to e^\\prime n \\pi^+$$, above the resonance region at backward pion center-of-mass angles. The $$\\varphi^*_{\\pi}$$-dependent cross sections were measured, from which we extracted three combinations of structure functions of the proton. Our results are compatible with calculations based on nucleon-to-pion transition distribution amplitudes (TDAs) and shed new light on nucleon structure.« less

Discrimination of Amplitude-Modulated Synthetic Echo Trains by an Echolocating Bottlenose Dolphin

DTIC Science & Technology

2002-07-09

resulted in improved echo categorization (Moore FIG. 1. (A) Enlargement of a single stimulus pulse (left) and its spectrum eta!., 1991; Roitblat eta!., 1991...Floyd, 1980; Moore et aL., 1991; Roitblat J. Acoust. Soc. Am., Vol. 112, No. 4, October 2002 Dankiewicz et al.: Discrimination of AM by an...Those studies were designed to elu- Harley, H. E., Roitblat , H. L., and Nachtigall, P. E. (1996). "Object repre- cidate the possible mechanisms by which

Scaling the amplitudes of the circadian pattern of resting oxygen consumption, body temperature and heart rate in mammals.

PubMed

Mortola, Jacopo P; Lanthier, Clement

2004-09-01

We questioned whether the amplitudes of the circadian pattern of body temperature (T(b)), oxygen consumption (V (O(2))) and heart rate (HR) changed systematically among species of different body weight (W). Because bodies of large mass have a greater heat capacitance than those of smaller mass, if the relative amplitude (i.e., amplitude/mean value) of metabolic rate was constant, one would expect the T(b) oscillation to decrease with the increase in the species W. We compiled data of T(b), V (O(2)) and HR from a literature survey of over 200 studies that investigated the circadian pattern of these parameters. Monotremata, Marsupials and Chiroptera, were excluded because of their characteristically low metabolic rate and T(b). The peak-trough ratios of V (O(2)) (42 species) and HR (35 species) averaged, respectively, 1.57+/-0.08, and 1.35+/-0.07, and were independent of W. The daily high values of T(b) did not change, while the daily low T(b) values slightly increased, with the species W; hence, the high-low T(b) difference (57 species) decreased with W (3.3 degrees C.W(-0.13)). However, the decrease in T(b) amplitude with W was much less than expected from physical principles, and the high-low T(b) ratio remained significantly above unity even in the largest mammals. Thus, it appears that in mammals, despite the huge differences in physical characteristics, the amplitude of the circadian pattern is a fixed (for V (O(2)) and HR), or almost fixed (for T(b)), fraction of the 24-h mean value. Presumably, the amplitudes of the oscillations are controlled parameters of physiological significance.

Traveling ionospheric disturbances observed by Kharkiv and Millstone Hill incoherent scatter radars near vernal equinox and summer solstice

NASA Astrophysics Data System (ADS)

Panasenko, Sergii V.; Goncharenko, Larisa P.; Erickson, Philip J.; Aksonova, Kateryna D.; Domnin, Igor F.

2018-07-01

We present the results of comparative study of traveling ionospheric disturbances (TIDs) obtained at middle latitudes of different longitudinal sectors during two coordinated observational campaigns. The joint measurements were conducted near the vernal equinox and summer solstice in 2016 using Kharkiv (49.6 N, 36.3 E) and Millstone Hill (42.6 N, 288.5 E) incoherent scatter radars. The same methods and software were used for analysis of both data sets to ensure consistency. We found that TIDs with periods of 40-80 min are observed during all measurements and concentrated predominantly near the sunrise and sunset terminators over both sites. There is no obvious relationship between the observed wave processes and variations in the auroral electrojet. Absolute and relative amplitudes, time of appearance, durations and phase differences of TIDs show strong height and seasonal variability. Relative amplitudes are substantially greater over Millstone Hill, whereas higher absolute amplitudes are observed over Kharkiv. During the summer solstice, the overall wave activity is smaller than during vernal equinox. Additional joint observations are needed to identify the seasonal and longitudinal dependences of TID characteristics.

Effects of different training amplitudes on heart rate and heart rate variability in young rowers.

PubMed

Vaz, Marcelo S; Picanço, Luan M; Del Vecchio, Fabrício B

2014-10-01

The aim of this study was to investigate the autonomic nervous system recovery and the psychological response as a result of 3 training amplitudes on heart rate (HR), heart rate variability (HRV), and rate of perceived exertion (RPE) in rowing. Eight young rowers (16.8 ± 1.4 years) performed, in a randomized fashion, 2 sessions of high-intensity interval training, with high and low amplitude and a continuous training (CT) session, with the same exercise duration (10 minutes) and mean intensity (60% of maximal stroke test). The data of HR, HRV, and RPE were collected 5 minutes before, immediately after each session, and 24 hours later. High amplitude promoted higher impact in maximum HR (p ≤ 0.05) and RPE (p < 0.001) when compared with CT. For the time domain HRV variable, there was a statistically significant difference between moments of rest (pretraining or post 24 hours) and posttraining in all training sessions. Originally, we conclude that training with higher load variation between effort and recovery impacts HRV, HR, and RPE with greater intensity, but the younger rowers were ready for new training sessions 24 hours after either training method. Coaches can use the polarized training method, observing the stimulus nature and time required for recovery, because it may be an adequate strategy for the development of rower's conditioning.

Relaxation Oscillations in the Nearly Inviscid Faraday System

NASA Astrophysics Data System (ADS)

Knobloch, Edgar; Higuera, Maria

2004-11-01

The amplitude equations for nearly inviscid Faraday waves couple to a streaming flow driven by oscillatory viscous boundary layers at the rigid walls and the free surface produced by the waves. This flow is driven most efficiently by mixed mode oscillations created in secondary bifurcations from standing waves, and these occur at small amplitude in containers that are almost symmetric.(M. Higuera, J.M. Vega and E. Knobloch. J. Nonlin. Sci. 12, 505, 2002.) Among the new dynamical behavior that results are relaxation oscillations involving abrupt transitions between standing and mixed mode oscillations. Such oscillations are present both in almost circular and in almost square containers. The origin of these oscillations will be explained and the results related to experiments.(F. Simonelli and J. P. Gollub, J. Fluid Mech. 199, 471, 1989.)footnote[3]Z.C. Feng and P.R. Sethna, J. Fluid Mech. 199, 495, 1989.

Beta-zone parapapillary atrophy and multifocal visual evoked potentials in eyes with glaucomatous optic neuropathy

PubMed Central

Ketner, Scott; Teng, Christopher C.; Ehrlich, Joshua R.; Raza, Ali S.; Liebmann, Jeffrey M.; Ritch, Robert; Hood, Donald C.

2015-01-01

We investigated changes in multifocal visual evoked potential (mfVEP) responses due to beta-zone parapapillary atrophy (βPPA). Patients with glaucomatous optic neuropathy (GON) with or without standard achromatic perimetry (SAP) abnormalities were referred for mfVEP testing during a 2-year period. Eyes with good quality optic disc stereophotographs and reliable SAP results were included. The mfVEP monocular mean latency delays (ms) and amplitudes (SNR) were analyzed. Age, SAP mean deviation (MD), pattern standard deviation (PSD), and spherical equivalent (SE) were analyzed in the multivariate model. Generalized estimated equations were used for comparisons between groups after adjusting for inter-eye associations. Of 394 eyes of 200 patients, 223 (57%) had βPPA. The βPPA eyes were older (59.6 ± 13.7 vs. 56.5 ± 13.7 year, P = 0.02), more myopic (−4.0 ± 3.5 vs. −1.3 ± 3.5 D, P < 0.01), and had poorer SAP scores (MD: −4.9 ± 5.2 vs. −2.6 ± 5.2 dB, P < 0.01; PSD: 4.3 ± 2.9 vs. 2.5 ± 3.0 dB, P < 0.01). By univariate analysis, mean latencies were longer in βPPA eyes (6.1 ± 5.3 vs. 4.0 ± 5.5 ms, P < 0.01). After adjusting for differences in SE, age, and SAP MD, there was no significant difference between the two groups (P = 0.09). βPPA eyes had lower amplitude log SNR (0.49 ± 0.16 vs. 0.56 ± 0.15, P < 0.01), which lost significance (P = 0.51) after adjusting for MD and PSD. Although eyes with βPPA had significantly lower amplitudes and prolonged latencies than eyes without βPPA, these differences were attributable to differences in SAP severity, age, and refractive error. Thus, βPPA does not appear to be an independent factor affecting mfVEP responses in eyes with GON. PMID:21735265

Maturation of the P3 and concurrent oscillatory processes during adolescence.

PubMed

Mathes, Birgit; Khalaidovski, Ksenia; Wienke, Annika S; Schmiedt-Fehr, Christina; Basar-Eroglu, Canan

2016-07-01

During adolescence event-related modulations of the neural response may increase. For slow event-related components, such as the P3, this developmental change may be masked due to increased amplitude levels of ongoing delta and theta oscillations in adolescents. In a cross-sectional study design, EEG was measured in 51 participants between 13 and 24years. A visual oddball paradigm was used to elicit the P3. Our analysis focused on fronto-parietal activations within the P3 time-window and the concurrent time-frequency characteristics in the delta (∼0.5-4Hz) and theta (∼4-7Hz) band. The parietal P3 amplitude was similar across the investigated age range, while the amplitude at frontal regions increased with age. The pre-stimulus amplitudes of delta and theta oscillations declined with age, while post-stimulus amplitude enhancement and inter-trial phase coherence increased. These changes affected fronto-parietal electrode sites. The parietal P3 maximum seemed comparable for adolescents and young adults. Detailed analysis revealed that within the P3 time-window brain maturation during adolescence may lead to reduced spontaneous slow-wave oscillations, increased amplitude modulation and time precision of event-related oscillations, and altered P3 scalp topography. Time-frequency analyses may help to distinguish selective neurodevelopmental changes within the P3 time window. Copyright © 2016 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.

Plasticity in neuromagnetic cortical responses suggests enhanced auditory object representation

PubMed Central

2013-01-01

Background Auditory perceptual learning persistently modifies neural networks in the central nervous system. Central auditory processing comprises a hierarchy of sound analysis and integration, which transforms an acoustical signal into a meaningful object for perception. Based on latencies and source locations of auditory evoked responses, we investigated which stage of central processing undergoes neuroplastic changes when gaining auditory experience during passive listening and active perceptual training. Young healthy volunteers participated in a five-day training program to identify two pre-voiced versions of the stop-consonant syllable ‘ba’, which is an unusual speech sound to English listeners. Magnetoencephalographic (MEG) brain responses were recorded during two pre-training and one post-training sessions. Underlying cortical sources were localized, and the temporal dynamics of auditory evoked responses were analyzed. Results After both passive listening and active training, the amplitude of the P2m wave with latency of 200 ms increased considerably. By this latency, the integration of stimulus features into an auditory object for further conscious perception is considered to be complete. Therefore the P2m changes were discussed in the light of auditory object representation. Moreover, P2m sources were localized in anterior auditory association cortex, which is part of the antero-ventral pathway for object identification. The amplitude of the earlier N1m wave, which is related to processing of sensory information, did not change over the time course of the study. Conclusion The P2m amplitude increase and its persistence over time constitute a neuroplastic change. The P2m gain likely reflects enhanced object representation after stimulus experience and training, which enables listeners to improve their ability for scrutinizing fine differences in pre-voicing time. Different trajectories of brain and behaviour changes suggest that the preceding effect of a P2m increase relates to brain processes, which are necessary precursors of perceptual learning. Cautious discussion is required when interpreting the finding of a P2 amplitude increase between recordings before and after training and learning. PMID:24314010

Target and beam-target spin asymmetries in exclusive pion electroproduction for Q2>1 GeV2. II. e p →e π0p

NASA Astrophysics Data System (ADS)

Bosted, P. E.; Kim, A.; Adhikari, K. P.; Adikaram, D.; Akbar, Z.; Amaryan, M. J.; Anefalos Pereira, S.; Avakian, H.; Badui, R. A.; Ball, J.; Balossino, I.; Battaglieri, M.; Bedlinskiy, I.; Biselli, A. S.; Boiarinov, S.; Briscoe, W. J.; Brooks, W. K.; Bültmann, S.; Burkert, V. D.; Cao, T.; Carman, D. S.; Celentano, A.; Chandavar, S.; Charles, G.; Chetry, T.; Ciullo, G.; Clark, L.; Colaneri, L.; Cole, P. L.; Contalbrigo, M.; Cortes, O.; Crede, V.; D'Angelo, A.; Dashyan, N.; De Vita, R.; De Sanctis, E.; Deur, A.; Djalali, C.; Dupre, R.; Egiyan, H.; El Alaoui, A.; El Fassi, L.; Elouadrhiri, L.; Eugenio, P.; Fanchini, E.; Fedotov, G.; Fegan, S.; Fersch, R.; Filippi, A.; Fleming, J. A.; Forest, T. A.; Fradi, A.; Ghandilyan, Y.; Gilfoyle, G. P.; Girod, F. X.; Glazier, D. I.; Gohn, W.; Golovatch, E.; Gothe, R. W.; Griffioen, K. A.; Guidal, M.; Guler, N.; Hakobyan, H.; Guo, L.; Hafidi, K.; Hakobyan, H.; Hanretty, C.; Harrison, N.; Hattawy, M.; Heddle, D.; Hicks, K.; Hollis, G.; Holtrop, M.; Hughes, S. M.; Ireland, D. G.; Isupov, E. L.; Jenkins, D.; Jiang, H.; Jo, H. S.; Joo, K.; Keller, D.; Khachatryan, G.; Khandaker, M.; Kim, W.; Klei, A.; Klein, F. J.; Koirala, S.; Kubarovsky, V.; Kuhn, S. E.; Lanza, L.; Lenisa, P.; Livingston, K.; Lu, H. Y.; MacGregor, I. J. D.; Markov, N.; Mayer, M.; McCracken, M. E.; McKinnon, B.; Mineeva, T.; Mirazita, M.; Mokeev, V. I.; Montgomery, R. A.; Movsisyan, A.; Munoz Camacho, C.; Murdoch, G.; Nadel-Turonski, P.; Ni, A.; Niccolai, S.; Niculescu, G.; Osipenko, M.; Ostrovidov, A. I.; Paolone, M.; Paremuzyan, R.; Park, K.; Pasyuk, E.; Phelps, W.; Pisano, S.; Pogorelko, O.; Price, J. W.; Prok, Y.; Protopopescu, D.; Puckett, A. J. R.; Raue, B. A.; Ripani, M.; Rizzo, A.; Rosner, G.; Rossi, P.; Roy, P.; Sabatié, F.; Saini, M. S.; Schumacher, R. A.; Seder, E.; Sharabian, Y. G.; Skorodumina, Iu.; Smith, G. D.; Sokhan, D.; Sparveris, N.; Stankovic, I.; Stepanyan, S.; Stoler, P.; Strakovsky, I. I.; Strauch, S.; Taiuti, M.; Tian, Ye; Torayev, B.; Ungaro, M.; Voskanyan, H.; Voutier, E.; Walford, N. K.; Watts, D. P.; Wei, X.; Weinstein, L. B.; Zachariou, N.; Zhang, J.; Zhao, Z. W.; Zonta, I.; CLAS Collaboration

2017-03-01

Beam-target double-spin asymmetries and target single-spin asymmetries were measured for the exclusive π0 electroproduction reaction γ*p →p π0 , expanding an analysis of the γ*p →n π+ reaction from the same experiment. The results were obtained from scattering of 6-GeV longitudinally polarized electrons off longitudinally polarized protons using the CEBAF Large Acceptance Spectrometer at Jefferson Laboratory. The kinematic ranges covered are 1.1

Longitudinal decrease in blood oxygenation level dependent response in cerebral amyloid angiopathy.

PubMed

Switzer, Aaron R; McCreary, Cheryl; Batool, Saima; Stafford, Randall B; Frayne, Richard; Goodyear, Bradley G; Smith, Eric E

2016-01-01

Lower blood oxygenation level dependent (BOLD) signal changes in response to a visual stimulus in functional magnetic resonance imaging (fMRI) have been observed in cross-sectional studies of cerebral amyloid angiopathy (CAA), and are presumed to reflect impaired vascular reactivity. We used fMRI to detect a longitudinal change in BOLD responses to a visual stimulus in CAA, and to determine any correlations between these changes and other established biomarkers of CAA progression. Data were acquired from 22 patients diagnosed with probable CAA (using the Boston Criteria) and 16 healthy controls at baseline and one year. BOLD data were generated from the 200 most active voxels of the primary visual cortex during the fMRI visual stimulus (passively viewing an alternating checkerboard pattern). In general, BOLD amplitudes were lower at one year compared to baseline in patients with CAA (p = 0.01) but were unchanged in controls (p = 0.18). The longitudinal difference in BOLD amplitudes was significantly lower in CAA compared to controls (p < 0.001). White matter hyperintensity (WMH) volumes and number of cerebral microbleeds, both presumed to reflect CAA-mediated vascular injury, increased over time in CAA (p = 0.007 and p = 0.001, respectively). Longitudinal increases in WMH (rs = 0.04, p = 0.86) or cerebral microbleeds (rs = -0.18, p = 0.45) were not associated with the longitudinal decrease in BOLD amplitudes.

The ERP correlates of self-knowledge: Are assessments of one's past, present, and future traits closer to semantic or episodic memory?

PubMed

Tanguay, Annick N; Benton, Lauren; Romio, Lorenza; Sievers, Carolin; Davidson, Patrick S R; Renoult, Louis

2018-02-01

Self-knowledge concerns one's own preferences and personality. It pertains to the self (similar to episodic memory), yet does not concern events. It is factual (like semantic memory), but also idiosyncratic. For these reasons, it is unclear where self-knowledge might fall on a continuum in relation to semantic and episodic memory. In this study, we aimed to compare the event-related potential (ERP) correlates of self-knowledge to those of semantic and episodic memory, using N400 and Late Positive Component (LPC) as proxies for semantic and episodic processing, respectively. We considered an additional factor: time perspective. Temporally distant selves have been suggested to be more semantic compared to the present self, but thinking about one's past and future selves may also engage episodic memory. Twenty-eight adults answered whether traits (e.g., persistent) were true of most people holding an occupation (e.g., soldiers; semantic memory condition), or true of themselves 5 years ago, in the present, or 5 years from now (past, present, and future self-knowledge conditions). The study ended with an episodic recognition memory task for previously seen traits. Present self-knowledge produced mean LPC amplitudes at posterior parietal sites that fell between semantic and episodic memory. Mean LPC amplitudes for past and future self-knowledge were greater than for semantic memory, and not significantly different from episodic memory. Mean N400 amplitudes for the self-knowledge conditions were smaller than for semantic memory at sagittal sites. However, this N400 effect was not separable from a preceding P200 effect at these same electrode sites. This P200 effect can be interpreted as reflecting the greater emotional salience of self as compared to general knowledge, which may have facilitated semantic processing. Overall, our findings are consistent with a distinction between knowledge of others and self-knowledge, but the closeness of self-knowledge's neural correlates to either semantic or episodic memory appears to depend to some extent on time perspective. Copyright © 2017 Elsevier Ltd. All rights reserved.

Neurophysiological and Behavioral Differences between Older and Younger Adults When Processing Violations of Tonal Structure in Music

PubMed Central

Lagrois, Marie-Élaine; Peretz, Isabelle; Zendel, Benjamin Rich

2018-01-01

Aging is associated with decline in both cognitive and auditory abilities. However, evidence suggests that music perception is relatively spared, despite relying on auditory and cognitive abilities that tend to decline with age. It is therefore likely that older adults engage compensatory mechanisms which should be evident in the underlying functional neurophysiology related to processing music. In other words, the perception of musical structure would be similar or enhanced in older compared to younger adults, while the underlying functional neurophysiology would be different. The present study aimed to compare the electrophysiological brain responses of younger and older adults to melodic incongruities during a passive and active listening task. Older and younger adults had a similar ability to detect an out-of-tune incongruity (i.e., non-chromatic), while the amplitudes of the ERAN and P600 were reduced in older adults compared to younger adults. On the other hand, out-of-key incongruities (i.e., non-diatonic), were better detected by older adults compared to younger adults, while the ERAN and P600 were comparable between the two age groups. This pattern of results indicates that perception of tonal structure is preserved in older adults, despite age-related neurophysiological changes in how melodic violations are processed. PMID:29487498

Neurophysiological and Behavioral Differences between Older and Younger Adults When Processing Violations of Tonal Structure in Music.

PubMed

Lagrois, Marie-Élaine; Peretz, Isabelle; Zendel, Benjamin Rich

2018-01-01

Aging is associated with decline in both cognitive and auditory abilities. However, evidence suggests that music perception is relatively spared, despite relying on auditory and cognitive abilities that tend to decline with age. It is therefore likely that older adults engage compensatory mechanisms which should be evident in the underlying functional neurophysiology related to processing music. In other words, the perception of musical structure would be similar or enhanced in older compared to younger adults, while the underlying functional neurophysiology would be different. The present study aimed to compare the electrophysiological brain responses of younger and older adults to melodic incongruities during a passive and active listening task. Older and younger adults had a similar ability to detect an out-of-tune incongruity (i.e., non-chromatic), while the amplitudes of the ERAN and P600 were reduced in older adults compared to younger adults. On the other hand, out-of-key incongruities (i.e., non-diatonic), were better detected by older adults compared to younger adults, while the ERAN and P600 were comparable between the two age groups. This pattern of results indicates that perception of tonal structure is preserved in older adults, despite age-related neurophysiological changes in how melodic violations are processed.

An approach to source characterization of tremor signals associated with eruptions and lahars

NASA Astrophysics Data System (ADS)

Kumagai, Hiroyuki; Mothes, Patricia; Ruiz, Mario; Maeda, Yuta

2015-11-01

Tremor signals are observed in association with eruption activity and lahar descents. Reduced displacement ( D R) derived from tremor signals has been used to quantify tremor sources. However, tremor duration is not considered in D R, which makes it difficult to compare D R values estimated for different tremor episodes. We propose application of the amplitude source location (ASL) method to characterize the sources of tremor signals. We used this method to estimate the tremor source location and source amplitude from high-frequency (5-10 Hz) seismic amplitudes under the assumption of isotropic S-wave radiation. We considered the source amplitude to be the maximum value during tremor. We estimated the cumulative source amplitude ( I s) as the offset value of the time-integrated envelope of the vertical seismogram of tremor corrected for geometrical spreading and medium attenuation in the 5-10-Hz band. For eruption tremor signals, we also estimated the cumulative source pressure ( I p) from an infrasonic envelope waveform corrected for geometrical spreading. We studied these parameters of tremor signals associated with eruptions and lahars and explosion events at Tungurahua volcano, Ecuador. We identified two types of eruption tremor at Tungurahua: noise-like inharmonic waveforms and harmonic oscillatory signals. We found that I s increased linearly with increasing source amplitude for lahar tremor signals and explosion events, but I s increased exponentially with increasing source amplitude for inharmonic eruption tremor signals. The source characteristics of harmonic eruption tremor signals differed from those of inharmonic tremor signals. We found a linear relation between I s and I p for both explosion events and eruption tremor. Because I p may be proportional to the total mass involved during an eruption episode, this linear relation suggests that I s may be useful to quantify eruption size. The I s values we estimated for inharmonic eruption tremor were consistent with previous estimates of volumes of tephra fallout. The scaling relations among source parameters that we identified will contribute to our understanding of the dynamic processes associated with eruptions and lahars. This new approach is applicable in analyzing tremor sources in real time and may contribute to early assessment of the size of eruptions and lahars.

Optical Turbulence on Underwater Image Degradation in Natural Environments

DTIC Science & Technology

2013-05-31

A. Laux, B. M. Concannon, E. P . Zege, I. L. Katsev, and A. S. Prikhach, "Amplitude-modulated Laser Imager," Appl. Opt. 43, 3874- 3892 (2004). 6. G...Security Symposium, R. A. W. Hou, ed. (SPIE, Orlando, FL, 2011), p . 8. 17 24 . A. Kanaev, W. Hou, and S. Woods, "Multi-frame Underwater Image...report ) Journal article (not refereed) Route Sheet No. !~3_!)!_ Job Order No. __ 73_:§~§.~~ 0_1- 5 Classification X u c Sponsor ONR ( ) Oral

Empirical Observations of Earthquake-Explosion Discrimination Using P/S Ratios and Implications for the Sources of Explosion S-Waves

DTIC Science & Technology

2007-09-01

stations at test sites around the world (e.g., Nevada, Lop Nor, Novaya Zemlya, Semipalatinsk , India, Pakistan, and North Korea). We show this pattern...regional P/S amplitudes tended to be dominated by frequencies around 1 Hz. As shown in Figure 2 at a number of major nuclear test sites , these...Figure 2. Bandpass filtered 1-2 Hz seismograms of earthquake (red) and explosion (blue) pairs at nuclear test sites show little consistent

Local measurement of error field using naturally rotating tearing mode dynamics in EXTRAP T2R

NASA Astrophysics Data System (ADS)

Sweeney, R. M.; Frassinetti, L.; Brunsell, P.; Fridström, R.; Volpe, F. A.

2016-12-01

An error field (EF) detection technique using the amplitude modulation of a naturally rotating tearing mode (TM) is developed and validated in the EXTRAP T2R reversed field pinch. The technique was used to identify intrinsic EFs of m/n  =  1/-12, where m and n are the poloidal and toroidal mode numbers. The effect of the EF and of a resonant magnetic perturbation (RMP) on the TM, in particular on amplitude modulation, is modeled with a first-order solution of the modified Rutherford equation. In the experiment, the TM amplitude is measured as a function of the toroidal angle as the TM rotates rapidly in the presence of an unknown EF and a known, deliberately applied RMP. The RMP amplitude is fixed while the toroidal phase is varied from one discharge to the other, completing a full toroidal scan. Using three such scans with different RMP amplitudes, the EF amplitude and phase are inferred from the phases at which the TM amplitude maximizes. The estimated EF amplitude is consistent with other estimates (e.g. based on the best EF-cancelling RMP, resulting in the fastest TM rotation). A passive variant of this technique is also presented, where no RMPs are applied, and the EF phase is deduced.

Gender effect in human brain responses to bottom-up and top-down attention using the EEG 3D-Vector Field Tomography.

PubMed

Kosmidou, Vasiliki E; Adam, Aikaterini; Papadaniil, Chrysa D; Tsolaki, Magda; Hadjileontiadis, Leontios J; Kompatsiaris, Ioannis

2015-01-01

The effect of gender in rapidly allocating attention to objects, features or locations, as reflected in brain activity, is examined in this study. A visual-attention task, consisting of bottom-up (visual pop-out) and top-down (visual search) conditions during stimuli of four triangles, i.e., a target and three distractors, was engaged. In pop-out condition, both color and orientation of the distractors differed from target, while in search condition they differed only in orientation. During the task, high-density EEG (256 channels) data were recorded and analyzed by means of behavioral, event-related potentials, i.e., the P300 component and brain source localization analysis using 3D-Vector Field Tomography (3D-VFT). Twenty subjects (half female; 32±4.7 years old) participated in the experiments, performing 60 trials for each condition. Behavioral analysis revealed that both female and male outperformed in the pop-out condition compared to the search one, with respect to accuracy and reaction time, whereas no gender-related statistical significant differences were found. Nevertheless, in the search condition, higher P300 amplitudes were detected for females compared to males (p <; 7 · 10(-3)). Moreover, the findings suggested that the maximum activation in females was located mainly in the left inferior frontal and superior temporal gyri, whereas in males it was found in the right inferior frontal and superior temporal gyri. Overall, the experimental results show that visual attention depends on contributions from different brain lateralization linked to gender, posing important implications in studying developmental disorders, characterized by gender differences.

Mechanism of impaired consciousness in absence seizures: a cross-sectional study

PubMed Central

Guo, Jennifer N.; Kim, Robert; Chen, Yu; Negishi, Michiro; Jhun, Stephen; Weiss, Sarah; Ryu, Jun Hwan; Bai, Xiaoxiao; Xiao, Wendy; Feeney, Erin; Rodriguez-Fernandez, Jorge; Mistry, Hetal; Crunelli, Vincenzo; Crowley, Michael J.; Mayes, Linda C.; Todd Constable, R.; Blumenfeld, Hal

2017-01-01

Background Absence seizures are brief episodes of impaired consciousness characterized by staring and behavioral arrest. The neural underpinnings of impaired consciousness and of the variable severity of behavioral impairment observed from one absence seizure to the next are not well understood. We therefore compared fMRI and EEG changes in absence seizures with impaired task performance to seizures in which performance was spared. Methods Patients were recruited from 59 pediatric neurology practices including hospitals and neurology outpatient offices throughout the United States. We performed simultaneous electroencephalography (EEG), fMRI, and behavioral testing in children and adolescents aged 6 to 19 years with typical absence epilepsy. fMRI and EEG were analyzed using data-driven approaches without prior assumptions about signal time courses or spatial distributions. The main outcomes were fMRI and EEG amplitudes in seizures with impaired versus spared behavioral responses analysed by t-test. We also examined the timing of fMRI and EEG changes in seizures with impaired behavioral responses compared to seizures with spared responses. Findings 93 patients were enrolled between September 1, 2005 and January 1, 2013, and we captured a total of 1032 seizures in 39 patients. fMRI changes during seizures occurred sequentially in three functional brain networks previously well-validated in studies of normal subjects. Seizures associated with more impaired behavior showed higher fMRI amplitude in all three networks compared to seizures with spared performance. In the default-mode network fMRI, amplitude was 0·57 ± 0·26% for seizures with impaired and 0·40 ± 0·16% for seizures with spared behavioral responses (mean difference 017%; 95% CI: 0·11 to 0·23%; p < 0.0001). In the task-positive network, fMRI amplitude was 0·53 ± 0·29% for impaired and 0·39 ± 0·15% for spared seizures (mean difference 0·14%; 95% CI: 008 to 0·21%; p < 0.0001). In the sensorimotor-thalamic network, fMRI amplitude was 0·41 ± 0·25% for impaired and 0·34 ± 014% for spared seizures (mean difference 0 07%; 95% CI: 001 to 0·13%; p = 0.02). Seizures with impaired behavior also showed greater EEG power in widespread brain regions compared to seizures with spared behavior. Mean fractional EEG power in the frontal leads was 50·4 ± 15·2 for seizures with impaired and 24·8 ± 6·5 for seizures with spared behavior (mean difference 25·6; 95% CI: 210 to 30·3); middle leads 35·4 ± 6·5 for impaired, 13 3 ± 34 for spared seizures (mean difference 22·1; 95% CI: 20.0 to 24·1); posterior leads 41·6 ± 5·3 for impaired, 24·6 ± 86 for spared seizures (mean difference 170; 95% CI: 14·4 to 19·7); p < 00001 for all comparisons. Average seizure duration was longer for seizures with impaired behavior at 79 ± 66 s, compared to 3·8 ± 3.0 s for seizures with spared behavior (mean difference 4.1 s; 95% CI 3.0 to 5.3 s, p < 00001). However, larger amplitude fMRI and EEG signals occurred at the outset or even preceding seizures with impairment. Interpretation Impaired consciousness in absence seizures is related to the intensity of physiological changes in established networks affecting widespread regions of the brain. Increased EEG and fMRI amplitude occurs at the onset of seizures associated with behavioral impairment. These findings suggest that a vulnerable state may exist at the initiation of some seizures leading to greater physiological changes and altered consciousness. PMID:27839650

Detecting seismic anisotropy across the 410 km discontinuity through polarity and amplitude variations of the underside reflections

NASA Astrophysics Data System (ADS)

Saki, Morvarid; Thomas, Christine; Merkel, Sebastien; Wookey, James

2017-04-01

We investigate the effect of various types of deformation mechanisms on the reflection coefficients of P and S waves underside reflections off the 410 km discontinuity, to find a diagnostic tool to detect the style of deformation at boundary layers. We calculate the reflection coefficient for P and SH underside reflections depending on the variation in velocity perturbations across the 410 km discontinuity for two deformation scenarios, compression and shear for different azimuths and angles of incidence at the interface. The results show that in the case of an anisotropic olivine layer above an isotropic wadsleyite layer, the P wave reflection coefficient amplitudes are only slightly influenced by the joint effect of angle of incidence and the strength of imposed deformation, without any polarity reversal and for all deformation styles. For the SH wave underside reflections a more complicated behaviour is visible: In compressional deformation, a polarity reversal occurs at distances depending on the incidence angle and the intensity of applied deformation without any azimuthal dependency. However, for shear geometry the azimuth to the direction of deformation appears as an important factor which strongly affects the incidence angle at which the polarity reversal of the reflected S wave occurs. These differences in amplitude and polarity patterns of reflection coefficients of different deformation geometries, especially for S wave at shorter distances allow to detect the style of deformation mechanisms at a boundary layer.

Early visual processing is enhanced in the midluteal phase of the menstrual cycle.

PubMed

Lusk, Bethany R; Carr, Andrea R; Ranson, Valerie A; Bryant, Richard A; Felmingham, Kim L

2015-12-01

Event-related potential (ERP) studies have revealed an early attentional bias in processing unpleasant emotional images in women. Recent neuroimaging data suggests there are significant differences in cortical emotional processing according to menstrual phase. This study examined the impact of menstrual phase on visual emotional processing in women compared to men. ERPs were recorded from 28 early follicular women, 29 midluteal women, and 27 men while they completed a passive viewing task of neutral and low- and high- arousing pleasant and unpleasant images. There was a significant effect of menstrual phase in early visual processing, as midluteal women displayed significantly greater P1 amplitude at occipital regions to all visual images compared to men. Both midluteal and early follicular women displayed larger N1 amplitudes than men (although this only reached significance for the midluteal group) to the visual images. No sex or menstrual phase differences were apparent in later N2, P3, or LPP. A condition effect demonstrated greater P3 and LPP amplitude to highly-arousing unpleasant images relative to all other stimuli conditions. These results indicate that women have greater early automatic visual processing compared to men, and suggests that this effect is particularly strong in women in the midluteal phase at the earliest stage of visual attention processing. Our findings highlight the importance of considering menstrual phase when examining sex differences in the cortical processing of visual stimuli. Copyright © 2015 Elsevier Ltd. All rights reserved.