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1

Microwave-evoked brainstem potentials in cats.  

PubMed

Rectangular pulse-modulated microwave radiation has been shown to produce auditory responses in mammals. It is therefore reasonable to explore the possibility of using microwave pulses to achieve an estimate of sensori-neural involvement in the objective evaluation of human hearing and to assess the presence of tumors or brainstem lesions in patients with neurological disorders. In this paper we shall show that microwave-evoked auditory response of cats closely resembles that evoked by acoustic pulse. We shall also give preliminary results obtained from electrodes fastened to the vertex of the skull after successive coagulative production of lesions in the inferior colliculus, lateral lemniscus, and superior olivary nucleus. PMID:261592

Lin, J C; Meltzer, R J; Redding, F K

1979-09-01

2

Brainstem Auditory Evoked Potential Study in Children with Autistic Disorder.  

ERIC Educational Resources Information Center

Brainstem auditory evoked potentials were compared in 109 children with infantile autism, 38 with autistic condition, 19 with mental retardation, and 20 normal children. Children with infantile autism or autistic condition had significantly longer brainstem transmission time than normal children suggesting neurological damage as the basis of…

Wong, Virginia; Wong, Sik Nin

1991-01-01

3

Binaural interaction in human auditory brainstem evoked potentials.  

PubMed

Binaural interaction was examined by recording human auditory brainstem responses to clicks from scalp electrodes. Deviations of binaurally evoked responses from the sum of monaurally evoked potentials were observed during waves IV through VI. Amplitude and latency of the interactions depended on click polarity: condensation clicks produced interactions of larger magnitude and longer latency than did rarefaction clicks. Latency differences cannot be accounted for by small latency shifts of the components of monaurally or binaurally evoked potentials resulting from changes in click polarity. Binaural interaction amplitude decreased as click intensity decreased and interaural delay increased. Attenuation of binaural interaction with interaural time differences was maximal at an interaural delay of 900 microseconds. Latency of interaction was prolonged in one subject with low- and high-frequency hearing loss; latency of binaural interaction in subjects with only high-frequency hearing loss was normal. These results suggest that binaural interaction in these potentials reflects binaural processing of low-frequency acoustic stimulation. PMID:7271536

Wrege, K S; Starr, A

1981-09-01

4

Comparison of binaural auditory brainstem responses and the binaural dierence potential evoked by chirps and clicks  

E-print Network

Comparison of binaural auditory brainstem responses and the binaural di¡erence potential evoked that compensate for the dispersion of the travelling wave on the basilar membrane evoke larger monaural brainstem auditory brainstem responses were recorded for clicks and chirps for levels from 10 to 60 dB nHL in steps

Oldenburg, Carl von Ossietzky, Universität

5

Brainstem auditory-evoked potentials in two meditative mental states  

PubMed Central

Context: Practicing mental repetition of “OM” has been shown to cause significant changes in the middle latency auditory-evoked potentials, which suggests that it facilitates the neural activity at the mesencephalic or diencephalic levels. Aims: The aim of the study was to study the brainstem auditory-evoked potentials (BAEP) in two meditation states based on consciousness, viz. dharana, and dhyana. Materials and Methods: Thirty subjects were selected, with ages ranging from 20 to 55 years (M=29.1; ±SD=6.5 years) who had a minimum of 6 months experience in meditating “OM”. Each subject was assessed in four sessions, i.e. two meditation and two control sessions. The two control sessions were: (i) ekagrata, i.e. single-topic lecture on meditation and (ii) cancalata, i.e. non-targeted thinking. The two meditation sessions were: (i) dharana, i.e. focusing on the symbol “OM” and (ii) dhyana, i.e. effortless single-thought state “OM”. All four sessions were recorded on four different days and consisted of three states, i.e. pre, during and post. Results: The present results showed that the wave V peak latency significantly increased in cancalata, ekagrata and dharana, but no change occurred during the dhyana session. Conclusions: These results suggested that information transmission along the auditory pathway is delayed during cancalata, ekagrata and dharana, but there is no change during dhyana. It may be said that auditory information transmission was delayed at the inferior collicular level as the wave V corresponds to the tectum. PMID:21170228

Kumar, Sanjay; Nagendra, HR; Naveen, KV; Manjunath, NK; Telles, Shirley

2010-01-01

6

Measurements of brain-stem auditory evoked potentials in infancy, childhood, and adolescence  

Microsoft Academic Search

Brain-stem auditory evoked potentials (BAEPs) were measured in 38 patients between 3 months and 18 years of age. In patients with blunt head injuries (N=28; 73.7%) no significant correlation between BAEP changes and final outcome could be established until day 36 with the exception of wave III changes in 3 children. Because various BAEP abnormalities occurred in all outcome groups

Christianto B. Lumenta; Michael Krämer; Carl Sprick; Ibrahim Dakroury; Wolfgang J. Bock

1985-01-01

7

Human brainstem auditory evoked potentials (BAEP) before and after MR examinations  

SciTech Connect

Recently significant changes of human brainstem auditory evoked potentials (BAEP) after exposure to static magnetic fields were reported. We recorded BAEPs of 11 subjects before and after a routine MRI examination at 1.5 T. In addition the BAEP of a healthy volunteer was measured in five different static magnetic fields (0-2.0 T). Our results indicate that routine MRI investigations do not significantly alter the interpeak latencies of the BAEPs.

Mueller, S.H.; Hotz, M. (University Hospital, Basel (Switzerland))

1990-12-01

8

Brain function in patients with cerebral fat embolism evaluated using somatosensory and brain-stem auditory evoked potentials  

Microsoft Academic Search

In two victims of traffic accidents with broken bones and fat embolism, serial recordings of somatosensory evoked potentials (SEPs) and brain-stem auditory evoked potentials (BAEPs) were examined to assess brain function. Initial SEPs and BAEPs revealed normal subcortical components, while the late cortical components of SEPs were abolished, findings indicative of diffuse dysfunction of grey rather than of white matter.

T. Morioka; H. Yagi

1989-01-01

9

F response and somatosensory and brainstem auditory evoked potential studies in HMSN type I and II.  

PubMed Central

To evaluate conduction along the proximal and distal segments of motor and sensory long limb nerves, as well as along the very short acoustic nerve, F response and somatosensory and brainstem auditory evoked potential were studied in a series of patients with hereditary motor and sensory neuropathy (HMSN) types I and II. A diffuse and comparable slowing of conduction in proximal and distal nerve segments, as well as along the acoustic nerve, seems to favour a primary myelin defect in HMSN I. F response and motor conduction velocity showed a similar derangement in both proximal and distal motor segments. Latencies of somatosensory evoked potentials were symmetrically prolonged and correlated with motor nerve impairment. Central conduction times were normal. Studies of brainstem auditory evoked potentials showed a high incidence of acoustic nerve involvement, the most evident abnormality being a statistically significant increase in the latency of the I wave. Our data seem to support the presence of primary myelinopathic damage in HMSN I. PMID:1469398

Scaioli, V; Pareyson, D; Avanzini, G; Sghirlanzoni, A

1992-01-01

10

[Brain-stem auditory evoked potentials and median latency in children with Down's syndrome].  

PubMed

We studied 20 milliseconds of the brainstem auditory evoked responses and 50 milliseconds of the middle latency responses in 11 children with Down's syndrome, between 6-9 years of age. The results were compared with those from 10 control children. We found a significative reduction of the amplitude of waves I, III, V in the former group. Central transmission time was shortest and frequently wave Pa was absent in patients with Down's syndrome patients. We hypothesized that the abnormalities of amplitude of the evoked responses may be related to presence of less neurons in the brain of patients with Down's syndrome. The reduction of central transmission time may be related to presence of microcephalia and significantly accelerated rates of action potential depolarization, repolarization and decreased spike duration. Wave Pa may have been absent due to microgyria of Heschl's temporal gyrus previously reported in patients with Down's syndrome. PMID:1837461

Poblano, A; Muñoz-Hernández, S E; Arias-Aranda, I; Castro Cue-De Carpizo, L; Montes de Oca-Fernández, E; de la Vega-De Teyssier, G

1991-11-01

11

Evaluation of desmethylmisonidazole-induced neurotoxicity in the rat using brainstem auditory evoked potentials  

SciTech Connect

Brainstem auditory evoked responses (BAEPs) and a scale that evaluates clinical signs of neurotoxicity were used to measure the onset of neurotoxic effects seen in rats after chronic injection of 400 mg/kg/day of the radiosensitizer desmethylmisonidazole (DMM) for 5 days/week for 7 weeks. A significant neurotoxic effect was indicated by increases in the latencies of peaks 4 and 5 of the BAEP after the 24th injection of DMM; clinical signs of neurotoxicity were observed after the 30th injection. Histologic examination of brainstems from rats sacrificed after selected number of injections during treatment showed that the onset of lesions in the brainstem was gradual but not extensive.

Edwards, M.S.B.; Gordon, D.G.; Levin, V.A.

1984-08-01

12

Hearing Screening of High-Risk Newborns with Brainstem Auditory Evoked Potentials: A Follow-Up Study.  

ERIC Educational Resources Information Center

The brainstem auditory evoked potential (BAEP) was evaluated as a hearing screening test in 168 high-risk newborns. The BAEP was found to be a sensitive procedure for the early identification of hearing-impaired newborns. However, the yield of significant hearing abnormalities was less than predicted in other studies using BAEP. (Author/CL)

Shannon, Dorothy A.; And Others

1984-01-01

13

Objective information-theoretic algorithm for detecting brainstem evoked responses to complex stimuli  

E-print Network

1 Objective information-theoretic algorithm for detecting brainstem evoked responses to complex evoked potential with putative neural generators in the rostral brainstem, provides a robust brainstem response can provide a completely objective and robust method for automated FFR detection

Dasgupta, Dipankar

14

Age and sex-related differences in brainstem auditory evoked potentials in secondary school students living in Northern European Russia  

Microsoft Academic Search

Brainstem auditory evoked potentials (BAEPs) were studied in 46 1st- to 11th-year students (22 boys and 24 girls) of a rural\\u000a secondary school in Arkhangel’sk oblast. The objective of this work was to study age- and sex-related differences in BAEP\\u000a characteristics in children and adolescents, living in the North and assess the BAEP characteristics as compared to reference\\u000a values. In

V. P. Rozhkov; S. I. Soroko

2009-01-01

15

A Novel Method of Brainstem Auditory Evoked Potentials Using Complex Verbal Stimuli  

PubMed Central

Background: The click and tone-evoked auditory brainstem responses are widely used in clinical practice due to their consistency and predictability. More recently, the speech-evoked responses have been used to evaluate subcortical processing of complex signals, not revealed by responses to clicks and tones. Aims: Disyllable stimuli corresponding to familiar words can induce a pattern of voltage fluctuations in the brain stem resulting in a familiar waveform, and they can yield better information about brain stem nuclei along the ascending central auditory pathway. Materials and Methods: We describe a new method with the use of the disyllable word “baba” corresponding to English “daddy” that is commonly used in many other ethnic languages spanning from West Africa to the Eastern Mediterranean all the way to the East Asia. Results: This method was applied in 20 young adults institutionally diagnosed as dyslexic (10 subjects) or light dyslexic (10 subjects) who were matched with 20 sex, age, education, hearing sensitivity, and IQ-matched normal subjects. The absolute peak latencies of the negative wave C and the interpeak latencies of A-C elicited by verbal stimuli “baba” were found to be significantly increased in the dyslexic group in comparison with the control group. Conclusions: The method is easy and helpful to diagnose abnormalities affecting the auditory pathway, to identify subjects with early perception and cortical representation abnormalities, and to apply the suitable therapeutic and rehabilitation management. PMID:25210677

Kouni, Sophia N; Koutsojannis, Constantinos; Ziavra, Nausika; Giannopoulos, Sotirios

2014-01-01

16

A Multicentre Database for Normative Brainstem Auditory Evoked Potentials (BAEPs) in Children: Methodology for Data Collection and Evaluation  

PubMed Central

Background: The influence of physiological and methodological factors on recordings of brainstem auditory evoked potentials (BAEPs) is greater in children than in adults. Objective: To collect and evaluate BAEP data in normal children, and measure intra- and inter-laboratory variability. Methods: Seven hundred and fifty unselected BAEP recordings were collected and evaluated from children ranging from neonates to 14-year-olds by eight laboratories in Italy. Results: In newborns, three laboratories showed satisfactory concordance; wave I was more broadly distributed than wave V and IPL I-V. The evaluation of pooled BAEP data from the older children showed that laboratories with age-matched data gave overlapping results; those with unmatched-age data differed significantly. The sound intensities of the laboratories did not significantly affect absolute BAEP latencies or IPLs. Females had shorter latencies than males; the difference was not significant. A single exponential regression model was an adequate but not the best predictor of normal data. Conclusions: The pooled data were consistent with the physiological maturation of the brainstem acoustic pathway. The BAEPs was reliably normalised using the natural logarithm of age. The differences between Centres were related to sample size, measurement accuracy, and inclusion and selection criteria. Significance: The creation of multicentre common database from an unmatched data collection is feasible and reliable enough for clinical diagnosis and multicentre clinical research. PMID:19911069

Scaioli, Vidmer; Brinciotti, Mario; Di Capua, Matteo; Lori, Silvia; Janes, Augusta; Pastorino, Giancarlo; Peruzzi, Cinzia; Sergi, Paola; Suppiej, Agnese

2009-01-01

17

Speech Evoked Auditory Brainstem Response in Stuttering  

PubMed Central

Auditory processing deficits have been hypothesized as an underlying mechanism for stuttering. Previous studies have demonstrated abnormal responses in subjects with persistent developmental stuttering (PDS) at the higher level of the central auditory system using speech stimuli. Recently, the potential usefulness of speech evoked auditory brainstem responses in central auditory processing disorders has been emphasized. The current study used the speech evoked ABR to investigate the hypothesis that subjects with PDS have specific auditory perceptual dysfunction. Objectives. To determine whether brainstem responses to speech stimuli differ between PDS subjects and normal fluent speakers. Methods. Twenty-five subjects with PDS participated in this study. The speech-ABRs were elicited by the 5-formant synthesized syllable/da/, with duration of 40?ms. Results. There were significant group differences for the onset and offset transient peaks. Subjects with PDS had longer latencies for the onset and offset peaks relative to the control group. Conclusions. Subjects with PDS showed a deficient neural timing in the early stages of the auditory pathway consistent with temporal processing deficits and their abnormal timing may underlie to their disfluency. PMID:25215262

Tahaei, Ali Akbar; Ashayeri, Hassan; Pourbakht, Akram; Kamali, Mohammad

2014-01-01

18

Altered brainstem auditory evoked potentials in a rat central sensitization model are similar to those in migraine.  

PubMed

Migraine symptoms often include auditory discomfort. Nitroglycerin (NTG)-triggered central sensitization (CS) provides a rodent model of migraine, but auditory brainstem pathways have not yet been studied in this example. Our objective was to examine brainstem auditory evoked potentials (BAEPs) in rat CS as a measure of possible auditory abnormalities. We used four subdermal electrodes to record horizontal (h) and vertical (v) dipole channel BAEPs before and after injection of NTG or saline. We measured the peak latencies (PLs), interpeak latencies (IPLs), and amplitudes for detectable waveforms evoked by 8, 16, or 32 kHz auditory stimulation. At 8 kHz stimulation, vertical channel positive PLs of waves 4, 5, and 6 (vP4, vP5, and vP6), and related IPLs from earlier negative or positive peaks (vN1-vP4, vN1-vP5, vN1-vP6; vP3-vP4, vP3-vP6) increased significantly 2h after NTG injection compared to the saline group. However, BAEP peak amplitudes at all frequencies, PLs and IPLs from the horizontal channel at all frequencies, and the vertical channel stimulated at 16 and 32 kHz showed no significant/consistent change. For the first time in the rat CS model, we show that BAEP PLs and IPLs ranging from putative bilateral medial superior olivary nuclei (P4) to the more rostral structures such as the medial geniculate body (P6) were prolonged 2h after NTG administration. These BAEP alterations could reflect changes in neurotransmitters and/or hypoperfusion in the midbrain. The similarity of our results with previous human studies further validates the rodent CS model for future migraine research. PMID:24680742

Arakaki, Xianghong; Galbraith, Gary; Pikov, Victor; Fonteh, Alfred N; Harrington, Michael G

2014-05-14

19

An evoked potential study of the developmental time course of the auditory nerve and brainstem in children using cochlear implants.  

PubMed

Central auditory responses to electrical stimulation from a cochlear implant were studied in 75 pre-lingually deafened children and 11 adults. Electrically evoked auditory brainstem response (EABR) latencies significantly decreased with duration of cochlear implant use and were not significantly affected by the age at implant activation. Significant decreases in early latency waves and interwaves occurred within the first 1-2 months of implant use, whereas longer term changes (6-12 months) were found for eV and eIII-eV, which measure activity in the more rostral brainstem. Comparisons to acoustically evoked auditory brainstem response (ABR) in children with normal hearing suggested shorter interwave EABR latencies, reflecting either distinct neural generators or increased neural synchrony, but similar rates of change in the later latency eV and eIII-eV with time in sound. In sum, normal-like development of the rostral auditory brainstem is promoted by cochlear implant use in children of a wide range of ages. PMID:16219994

Gordon, Karen A; Papsin, Blake C; Harrison, Robert V

2006-01-01

20

A model for simulation of electrically evoked auditory brainstem responses  

NASA Astrophysics Data System (ADS)

An important aspect of research in the continued development of cochlear implants is the in vivo assessment of signal processing algorithms. One technique that has been used is evoked potentials, the recording of neural responses to auditory stimulation. Depending on the latency of the observed response, the evoked potential indicates neural activity at the various neurological structures of the auditory system. Electrically evoked ABRs are commonly measured in hearing-impaired patients who have cochlear implants, via electrical stimulation delivered by electrodes in the implanted array. This research explores the use of MATLAB for the purpose of developing a model for electrically evoked auditory brainstem responses (ABRs). The simulation model developed in this study takes as its input the stimulus current intensity level, and uses function vectors and equations derived from measured ABRs, to generate an approximation of the evoked surface potentials. A function vector is used to represent the combined firing of the neurons of the auditory nervous system that are needed to elicit a measurable response. Equations have been derived to represent the latency and stimulus amplitude scaling functions. The simulation also accounts for other neural activity that can be present in and contaminate an ABR recording, and reduces it through time-locked averaging of the simulated response. In the MATLAB simulation, the model performs well and delivers results that compare favorably with the results measured from the research subjects.

Miller, Douglas A.; Matin, Mohammed A.

2009-08-01

21

Auditory brain-stem evoked potentials in cat after kainic acid induced neuronal loss. I. Superior olivary complex.  

PubMed

Auditory brain-stem potentials (ABRs) were studied in cats for up to 45 days after kainic acid had been injected unilaterally or bilaterally into the superior olivary complex (SOC) to produce neuronal destruction while sparing fibers of passage and the terminals of axons of extrinsic origin connecting to SOC neurons. The components of the ABR in cat were labeled by their polarity at the vertex (P, for positive) and their order of appearance (the arabic numerals 1, 2, etc.). Component P1 can be further subdivided into 2 subcomponents labeled P1a and P1b. The correspondences we have assumed between the ABR components in cat and man are indicated by providing a Roman numeral designation for the human component in parentheses following the feline notation, e.g., P4 (V). With bilateral SOC destruction, there was a significant and marked attenuation of waves P2 (III), P3 (IV), P4 (V), P5 (VI), and the sustained potential shift (SPS) amounting to as much as 80% of preoperative values. Following unilateral SOC destruction the attenuation of many of these same ABR components, in response to stimulation of either ear, was up to 50%. No component of the ABR was totally abolished even when the SOC was lesioned 100% bilaterally. In unilaterally lesioned cats with extensive neuronal loss (greater than 75%) the latencies of the components beginning at P3 (IV) were delayed to stimulation of the ear ipsilateral to the injection site but not to stimulation of the ear contralateral to the injection. Binaural interaction components of the ABR were affected in proportion to the attenuation of the ABR. These results are compatible with multiple brain regions contributing to the generation of the components of the ABR beginning with P2 (III) and that components P3 (IV), P4 (V), and P5 (VI) and the sustained potential shift depend particularly on the integrity of the neurons of the SOC bilaterally. The neurons of the lateral subdivision (LSO) and the medial nucleus of the trapezoid body (MNTB) of the SOC have a major role in generating waves P3 (IV) and P4 (V). PMID:1716568

Zaaroor, M; Starr, A

1991-01-01

22

Auditory brain-stem evoked potentials in cat after kainic acid induced neuronal loss. II. Cochlear nucleus.  

PubMed

Auditory brain-stem potentials (ABRs) were studied in cats for up to 6 weeks after kainic acid had been injected unilaterally into the cochlear nucleus (CN) producing extensive neuronal destruction. The ABR components were labeled by the polarity at the vertex (P, for positive) and their order of appearance (the arabic numerals 1, 2, etc.). Component P1 can be further subdivided into 2 subcomponents, P1a and P1b. The assumed correspondence between the ABR components in cat and man is indicated by providing human Roman numeral designations in parentheses following the feline notation, e.g., P2 (III). To stimulation of the ear ipsilateral to the injection, the ABR changes consisted of a loss of components P2 (III) and P3 (IV), and an attenuation and prolongation of latency of components P4 (V) and P5 (VI). The sustained potential shift from which the components arose was not affected. Wave P1a (I) was also slightly but significantly attenuated compatible with changes of excitability of nerve VIII in the cochlea secondary to cochlear nucleus destruction. Unexpectedly, to stimulation of the ear contralateral to the injection side, waves P2 (III), P3 (IV), and P4 (V) were also attenuated and delayed in latency but to a lesser degree than to stimulation of the ear ipsilateral to the injection. Changes in binaural interaction of the ABR following cochlear nucleus lesions were similar to those produced in normal animals by introducing a temporal delay of the input to one ear. The results of the present set of studies using kainic acid to induce neuronal loss in auditory pathway when combined with prior lesion and recording experiments suggest that each of the components of the ABR requires the integrity of an anatomically diffuse system comprising a set of neurons, their axons, and the neurons on which they terminate. Disruption of any portion of the system will alter the amplitude and/or the latency of that component. PMID:1716569

Zaaroor, M; Starr, A

1991-01-01

23

Developmental exposure to purity-controlled polychlorinated biphenyl congeners (PCB74 and PCB95) in rats: Effects on brainstem auditory evoked potentials and catalepsy.  

PubMed

Whereas the effects of dioxin-like polychlorinated biphenyls (DL-PCBs) are well described, less is known about non-dioxin-like PCBs (NDL-PCBs), including influences on the nervous system and related behavioral effects after developmental exposure. Following the examination of the highly purified NDL congeners PCB52 and PCB180, we report here the results of experiments with PCB74 and PCB95. Rat dams were orally exposed to equimolar doses of either congener (40?mol/kg bw - 11.68mg PCB74/kg bw or 13.06mg PCB95/kg bw) from gestational day (GD) 10 to postnatal day (PND) 7. Control dams were given the vehicle. Adult offspring were tested for cataleptic behavior after induction with haloperidol, a classical neuroleptic drug, and brainstem auditory evoked potentials (BAEPs), using clicks and tone pips of different frequencies for stimulation. Results revealed slight effects on latencies to movement onset in female offspring exposed to PCB74, whereas PCB74 males and offspring exposed to PCB95 were not affected. Pronounced changes were observed in BAEPs at low frequencies in PCB74 offspring, with elevated thresholds in both sexes. PCB95 increased thresholds in males, but not females. Small effects were detected on latency of the late wave IV in both sexes after developmental exposure to PCB74 or PCB95. Compared with the other NDL-PCB congeners tested, PCB74 caused the most pronounced effects on BAEPs. PMID:25449634

Lilienthal, Hellmuth; Korkalainen, Merja; Andersson, Patrik L; Viluksela, Matti

2015-01-01

24

Research Paper Test-retest consistency of speech-evoked auditory brainstem responses  

E-print Network

Research Paper Test-retest consistency of speech-evoked auditory brainstem responses in typically-evoked auditory brainstem response (ABR) is widely used in clinical settings, partly due to its predictability of months. However, a systematic study of the consistency of the speech-evoked brainstem response in school

25

Testretest reliability of the speech-evoked auditory brainstem response Judy H. Song a,b  

E-print Network

Test­retest reliability of the speech-evoked auditory brainstem response Judy H. Song a,b , Trent-evoked ABR Speech-in-noise Brainstem encoding BioMARK a b s t r a c t Objective: The speech-evoked auditory brainstem response (ABR) provides an objective measure of sub- cortical encoding of complex acoustic

26

Auditory Brainstem Evoked Responses in Newborns with Down Syndrome  

ERIC Educational Resources Information Center

Auditory brainstem evoked responses (ABRs) were compared in 15 newborns with Down syndrome and 15 sex-, age-, and weight-matched control newborns. Participants had normal ABRs based upon values specific to 32- to 42-weeks postconceptional age. Although Wave III and Wave V component latencies and the Wave I-III interpeak latency (IPL) were shorter…

Kittler, Phyllis M.; Phan, Ha T. T.; Gardner, Judith M.; Miroshnichenko, Inna; Gordon, Anne; Karmel, Bernard Z.

2009-01-01

27

Newborn Auditory Brainstem Evoked Responses (ABRs): Prenatal and Contemporary Correlates.  

ERIC Educational Resources Information Center

Presented are a literature review and new data on correlates of newborn auditory brainstem evoked responses (ABRs). Concludes that disorders of the central components of the ABR may be more of prenatal than of postnatal origin. The I-V interval had low but reliable correlations with four of 11 Brazelton scale variables. (RH)

Murray, Ann D.

1988-01-01

28

Auditory Detection of the Human Brainstem Auditory Evoked Response.  

ERIC Educational Resources Information Center

This study evaluated whether listeners can distinguish human brainstem auditory evoked responses elicited by acoustic clicks from control waveforms obtained with no acoustic stimulus when the waveforms are presented auditorily. Detection performance for stimuli presented visually was slightly, but consistently, superior to that which occurred for…

Kidd, Gerald, Jr.; And Others

1993-01-01

29

Brainstem Auditory Evoked Response in Children with Central Language Disturbance.  

ERIC Educational Resources Information Center

Two groups of 10 children between the ages of 94 and 165 months were paired for age (wthin 6 months) and sex and were compared for Brainstem Auditory Evoked Response patterns. One child in each pair showed evidence of central language disturbance as determined by neuropsychological testing. The other did not. All had normal hearing and IQs of 80…

Piggott, Leonard R.; Anderson, Theodora

1983-01-01

30

The Theoretical Distribution of Evoked Brainstem Activity in Preterm, High-Risk, and Healthy Infants.  

ERIC Educational Resources Information Center

Determines the frequency distribution of Brainstem Auditory Evoked Potential variables (BAEP) for premature babies at different stages of development--normal newborns, infants, young children, and adults. The author concludes that the assumption of normality underlying most "standard" statistical analyses can be met for many BAEP measures.…

Salamy, A.

1981-01-01

31

Speech-evoked auditory brainstem responses reflect familial and cognitive influences  

E-print Network

PAPER Speech-evoked auditory brainstem responses reflect familial and cognitive influences Jane brainstem response to speech is linked to language skill, reading ability, cognitive skills, and speech investigated. We assessed auditory brainstem responses to speech presented in quiet and background noise from

Kraus, Nina

32

The binaural click-evoked auditory brainstem response of the California sea lion (Zalophus californianus)  

E-print Network

The binaural click-evoked auditory brainstem response of the California sea lion (Zalophus November 2012; accepted 20 November 2012) Auditory brainstem responses (ABRs) elicited by high system, including the processes that underlie brainstem auditory steady-state responses used to measure

Reichmuth, Colleen

33

Development of Brainstem-Evoked Responses in Congenital Auditory Deprivation  

PubMed Central

To compare the development of the auditory system in hearing and completely acoustically deprived animals, naive congenitally deaf white cats (CDCs) and hearing controls (HCs) were investigated at different developmental stages from birth till adulthood. The CDCs had no hearing experience before the acute experiment. In both groups of animals, responses to cochlear implant stimulation were acutely assessed. Electrically evoked auditory brainstem responses (E-ABRs) were recorded with monopolar stimulation at different current levels. CDCs demonstrated extensive development of E-ABRs, from first signs of responses at postnatal (p.n.) day 3 through appearance of all waves of brainstem response at day 8?p.n. to mature responses around day 90?p.n.. Wave I of E-ABRs could not be distinguished from the artifact in majority of CDCs, whereas in HCs, it was clearly separated from the stimulus artifact. Waves II, III, and IV demonstrated higher thresholds in CDCs, whereas this difference was not found for wave V. Amplitudes of wave III were significantly higher in HCs, whereas wave V amplitudes were significantly higher in CDCs. No differences in latencies were observed between the animal groups. These data demonstrate significant postnatal subcortical development in absence of hearing, and also divergent effects of deafness on early waves II–IV and wave V of the E-ABR. PMID:22792488

Tillein, J.; Heid, S.; Lang, E.; Hartmann, R.; Kral, A.

2012-01-01

34

SOMATOSENSORY EVOKED POTENTIALS  

EPA Science Inventory

Somatosensory evoked potentials (SEPs) have been used by neuroscientists for many years. The versatility of the method is attested to be the differing purposes to which it has been applied. Initially, SEPs were used to uncover basic principles of sensory processing. A casual glan...

35

SUPERIOR COLLICULUS LESIONS AND FLASH EVOKED POTENTIALS FROM RAT CORTEX  

EPA Science Inventory

It is generally assumed that the primary response of the rat flash evoked potential (FEP) is activated by a retino-geniculate pathway, and that the second response reflects input to the cortex by way of the superior colliculus (SC) or other brainstem structures. In the present st...

36

UNRECOGNIZED ERRORS DUE TO ANALOG FILTERING OF THE BRAIN-STEM AUDITORY EVOKED RESPONSE  

EPA Science Inventory

The brainstem auditory evoked response (BAER) is used as a tool both in clinical evaluation and in toxicological research, where the subject is most often the laboratory rat. As in other species, interpretation of the rat BAER waveform is based on the latencies and amplitudes of ...

37

Aberrant Lateralization of Brainstem Auditory Evoked Responses by Individuals with Down Syndrome.  

ERIC Educational Resources Information Center

Brainstem auditory evoked response latencies were studied in 80 males (13 with Down's syndrome). Latencies for waves P3 and P5 were shorter for Down's syndrome subjects, who also showed a different pattern of left versus right ear responses. Results suggest decreased lateralization and receptive and expressive language ability among people with…

Miezejeski, Charles M.; And Others

1994-01-01

38

Infant Temperament and the Brainstem Auditory Evoked Response in Later Childhood.  

ERIC Educational Resources Information Center

Evaluated brainstem auditory evoked responses (BAERs) on 10- to 12-year-olds who had been classified as high or low reactive to unfamiliar stimuli at 4 months of age. Found that children previously classified as high reactive at 4 months had larger wave V components than did low reactive children, possibly suggesting greater excitability in…

Woodward, Sue A.; McManis, Mark H.; Kagan, Jerome; Deldin, Patricia; Snidman, Nancy; Lewis, Melissa; Kahn, Vali

2001-01-01

39

Newborn Auditory Brainstem Evoked Responses (ABRs): Longitudinal Correlates in the First Year.  

ERIC Educational Resources Information Center

Aimed to determine to what degree newborns' auditory brainstem evoked responses (ABRs) predict delayed or impaired development during the first year. When 93 infants' ABRs were evaluated at three, six, and nine months, newborn ABR was moderately sensitive for detecting hearing impairment and more sensitive than other indicators in detecting…

Murray, Ann D.

1988-01-01

40

DIFFERENTIAL IMPACT OF HYPOTHERMIA AND PENTOBARBITAL ON BRAINSTEM AUDITORY EVOKED RESPONSE  

EPA Science Inventory

Two experiments were conducted to determine the effects of hypothermia and pentobarbital anesthesia, alone and in combination, on the brainstem auditory evoked responses (BAERs) of rats. n experiment I, unanesthetized rats were cooled to colonic temperatures 0.5 and 1.0 degrees C...

41

[Brain stem auditory evoked potentials in obstructive sleep apnea syndrome].  

PubMed

To evaluate a possible brainstem role in pathogenesis of obstructive sleep apnea syndrome, a study on brainstem auditory evoked potentials (BAEP), has been conducted. 15 OSAS patients, medium and severe form, with organic pathologies of the upper respiratory tract have been evaluated. 15 normal subjects were compared as control. All the patients were subjected to audiometry, including total liminal audiometry, timpanometry, acustic reflex, and BAEP study. BAEP evoked with trains of cliks at 11 and 51 periods/sec., showed morphological alterations and a longer central conductance of time interval (I-V interval) in only four patients. BAEP alterations noted in the OSAS-affected patients are neither constant nor specific. Therefore, the observed BAEP alterations might be due to apneas, as a consequence of the chronic hypoxic- hypercapnic status occurring in the brain-stem. PMID:7484151

Cimino, A; Speciale, R; Gallina, S; Cimino, M; Chillura, M; Lo Presti, G M; Ciulla, L

1995-04-01

42

Auditory and Visual Evoked Potentials in Individuals with Organic and Cultural-Familial Mental Retardation.  

ERIC Educational Resources Information Center

Brainstem, middle-latency, and long-latency auditory-evoked potentials and visual-evoked potentials were recorded for 66 individuals (ages 9-19) in the following comparison groups: cultural-familial mentally retarded, organically mentally retarded, and nonretarded. Target stimuli were evaluated more slowly by both groups with mental retardation.…

Zurron, Montserrat; Diaz, Fernando

1995-01-01

43

Evoked potentials in chronic n-hexane intoxication  

SciTech Connect

Somatosensory, brainstem auditory and pattern-reversal visual evoked potentials (SEP, BAEP and PVEP) were studied in 5 patients with n-hexane polyneuropathy to determine if the CNS was affected. In SEPs, the median central conduction (N13-to-N20) was normal but the tibial central conduction (N22-to-P40) was delayed. The central conduction time (I-to-V interval) of the BAEP was also prolonged. However, the P100 latency of the PVEP was normal. The present data indicate that the spinal cord and the brainstem are primarily affected in chronic n-hexane intoxication.

Huang, C.C.; Chu, N.S. (Chang Gung Medical College, Taipei, Taiwan (China))

1989-07-01

44

Electrically-evoked frequency-following response (EFFR) in the auditory brainstem of guinea pigs.  

PubMed

It is still a difficult clinical issue to decide whether a patient is a suitable candidate for a cochlear implant and to plan postoperative rehabilitation, especially for some special cases, such as auditory neuropathy. A partial solution to these problems is to preoperatively evaluate the functional integrity of the auditory neural pathways. For evaluating the strength of phase-locking of auditory neurons, which was not reflected in previous methods using electrically evoked auditory brainstem response (EABR), a new method for recording phase-locking related auditory responses to electrical stimulation, called the electrically evoked frequency-following response (EFFR), was developed and evaluated using guinea pigs. The main objective was to assess feasibility of the method by testing whether the recorded signals reflected auditory neural responses or artifacts. The results showed the following: 1) the recorded signals were evoked by neuron responses rather than by artifact; 2) responses evoked by periodic signals were significantly higher than those evoked by the white noise; 3) the latency of the responses fell in the expected range; 4) the responses decreased significantly after death of the guinea pigs; and 5) the responses decreased significantly when the animal was replaced by an electrical resistance. All of these results suggest the method was valid. Recording obtained using complex tones with a missing fundamental component and using pure tones with various frequencies were consistent with those obtained using acoustic stimulation in previous studies. PMID:25244253

He, Wenxin; Ding, Xiuyong; Zhang, Ruxiang; Chen, Jing; Zhang, Daoxing; Wu, Xihong

2014-01-01

45

Electrically-Evoked Frequency-Following Response (EFFR) in the Auditory Brainstem of Guinea Pigs  

PubMed Central

It is still a difficult clinical issue to decide whether a patient is a suitable candidate for a cochlear implant and to plan postoperative rehabilitation, especially for some special cases, such as auditory neuropathy. A partial solution to these problems is to preoperatively evaluate the functional integrity of the auditory neural pathways. For evaluating the strength of phase-locking of auditory neurons, which was not reflected in previous methods using electrically evoked auditory brainstem response (EABR), a new method for recording phase-locking related auditory responses to electrical stimulation, called the electrically evoked frequency-following response (EFFR), was developed and evaluated using guinea pigs. The main objective was to assess feasibility of the method by testing whether the recorded signals reflected auditory neural responses or artifacts. The results showed the following: 1) the recorded signals were evoked by neuron responses rather than by artifact; 2) responses evoked by periodic signals were significantly higher than those evoked by the white noise; 3) the latency of the responses fell in the expected range; 4) the responses decreased significantly after death of the guinea pigs; and 5) the responses decreased significantly when the animal was replaced by an electrical resistance. All of these results suggest the method was valid. Recording obtained using complex tones with a missing fundamental component and using pure tones with various frequencies were consistent with those obtained using acoustic stimulation in previous studies. PMID:25244253

Zhang, Ruxiang; Chen, Jing; Zhang, Daoxing; Wu, Xihong

2014-01-01

46

Brainstem auditory evoked responses in man. 1: Effect of stimulus rise-fall time and duration  

NASA Technical Reports Server (NTRS)

Short latency (under 10 msec) evoked responses elicited by bursts of white noise were recorded from the scalp of human subjects. Response alterations produced by changes in the noise burst duration (on-time) inter-burst interval (off-time), and onset and offset shapes are reported and evaluated. The latency of the most prominent response component, wave V, was markedly delayed with increases in stimulus rise-time but was unaffected by changes in fall-time. The amplitude of wave V was insensitive to changes in signal rise-and-fall times, while increasing signal on-time produced smaller amplitude responses only for sufficiently short off-times. It is concluded that wave V of the human auditory brainstem evoked response is solely an onset response.

Hecox, K.; Squires, N.; Galambos, R.

1975-01-01

47

Human auditory evoked potentials. I - Evaluation of components  

NASA Technical Reports Server (NTRS)

Fifteen distinct components can be identified in the scalp recorded average evoked potential to an abrupt auditory stimulus. The early components occurring in the first 8 msec after a stimulus represent the activation of the cochlea and the auditory nuclei of the brainstem. The middle latency components occurring between 8 and 50 msec after the stimulus probably represent activation of both auditory thalamus and cortex but can be seriously contaminated by concurrent scalp muscle reflex potentials. The longer latency components occurring between 50 and 300 msec after the stimulus are maximally recorded over fronto-central scalp regions and seem to represent widespread activation of frontal cortex.

Picton, T. W.; Hillyard, S. A.; Krausz, H. I.; Galambos, R.

1974-01-01

48

Peak Morphology and Scalp Topography of the Pharyngeal Sensory-Evoked Potential  

Microsoft Academic Search

The initiation of the pharyngeal stage of swallowing is dependent upon sensory input to the brainstem and cortex. The event-related\\u000a evoked potential provides a measure of neuronal electrical activity as it relates to a specific stimulus. Air-puff stimulation\\u000a to the posterior pharyngeal wall produces a sensory-evoked potential (PSEP) waveform. The goal of this study was to characterize\\u000a the scalp topography

Karen Wheeler-Hegland; Teresa Pitts; Paul W. Davenport

49

Evidence from Auditory Nerve and Brainstem Evoked Responses for an Organic Brain Lesion in Children with Autistic Traits  

ERIC Educational Resources Information Center

In an attempt to resolve the question as to whether children with autistic traits have an organic nervous system lesion, auditory nerve and brainstem evoked responses were recorded in a group of 15 children (4 to 12 years old) with autistic traits. (Author)

Student, M.; Sohmer, H.

1978-01-01

50

Brainstem auditory evoked responses in man. 1: Effect of stimulus rise-fall time and duration  

NASA Technical Reports Server (NTRS)

Short latency (under 10 msec) responses elicited by bursts of white noise were recorded from the scalps of human subjects. Response alterations produced by changes in the noise burst duration (on-time), inter-burst interval (off-time), and onset and offset shapes were analyzed. The latency of the most prominent response component, wave V, was markedly delayed with increases in stimulus rise time but was unaffected by changes in fall time. Increases in stimulus duration, and therefore in loudness, resulted in a systematic increase in latency. This was probably due to response recovery processes, since the effect was eliminated with increases in stimulus off-time. The amplitude of wave V was insensitive to changes in signal rise and fall times, while increasing signal on-time produced smaller amplitude responses only for sufficiently short off-times. It was concluded that wave V of the human auditory brainstem evoked response is solely an onset response.

Hecox, K.; Squires, N.; Galambos, R.

1975-01-01

51

USE OF SENSORY EVOKED POTENTIALS IN TOXICOLOGY  

EPA Science Inventory

The rationale for studying sensory systems as an integral part of neurotoxicological examinations is presented. The role of evoked potentials in assessing brain dysfunction in general and sensory systems in particular is also presented. Four types of sensory evoked potentials (br...

52

Brainstem auditory-evoked response (BAER) in client-owned pet ferrets with normal hearing.  

PubMed

The objective of this study was to evaluate the feasibility of brainstem auditory-evoked response (BAER) testing in pet ferrets in a clinical setting, and to describe a routine method and baseline data for normal hearing ferrets for future investigation of deafness in this species. Twenty-eight clinically normal client-owned ferrets were included. BAER measurements were recorded under general anaesthesia (isoflurane delivered by mask), from subcutaneously placed needle electrodes. A 'click' stimulus applied by insert earphone with an intensity of 90?dB sound pressure level (SPL) was used. The final BAER waveform represents an average of 500 successive responses. Morphology of the waveform was studied; amplitude and latency measures were determined and means were calculated. The BAER waveform of the normal ferret included 4 reproducible waves named I, II, III and V, as previously described in dogs and cats. Measurements of latencies are consistent with previous laboratory research using experimental ferrets. In the present study, a reliable routine protocol for clinical evaluation of the hearing function in the pet ferret was established. This procedure can be easily and safely performed in a clinical setting in ferrets as young as eight weeks of age. The prevalence of congenital deafness in ferrets is currently unknown but may be an important consideration, especially in ferrets with a white coat. BAER test is a useful screening for congenital deafness in this species. PMID:24714054

Piazza, S; Huynh, M; Cauzinille, L

2014-06-01

53

Use of evoked potentials in preterm neonates.  

PubMed Central

This paper has reviewed the techniques used for recording evoked potentials in the premature infant and the early developmental changes. The maturational changes in the evoked potentials, including morphological changes, and the very rapid latency changes within the first months of life, provide an invaluable means for assessing and monitoring development within the central nervous system. The maturational changes are such that normative values are requisite, and the norms must take into account both the infant's gestational age at birth as well as the postnatal age. These norms can then be used to aid in the assessment of gestational age, and whether there has or has not been normal maturational development, either in utero or during the postnatal preterm period. Evoked potentials are of increasing value clinically in preterm neonates, primarily because of the difficulty in obtaining reliable neurological evaluation of these infants. Median nerve SEPs may provide reliable information in preterm infants at risk of PVL, and when recorded in the second week of life, predict cerebral palsy. PTN SEPs seem to be even more reliable indicators of outcome, but the difficulty in obtaining them in preterm infants needs to be taken into consideration. Further study is needed in some areas, such as in apnoeic preterm babies clearly to establish the role that evoked potentials (in this case BAEPs) may have in understanding both the aetiology and the clinical course of this dysfunction. In other conditions, such as delayed intrauterine growth, that may lead to neurological sequelae, evoked potentials can provide objective CNS assessment. Evoked potentials may also prove useful in the monitoring of treatment modalities for preterm infants. The evoked potentials are a valuable adjunct in the assessment of preterm neonates and, as their value is recognised, we expect their use to increase. PMID:8653441

Taylor, M. J.; Saliba, E.; Laugier, J.

1996-01-01

54

Association of Hemoglobin levels and Brainstem Auditory Evoked Responses in Lead-Exposed Children  

PubMed Central

Objectives Decreased blood hemoglobin (HbB) levels and anemia have been associated with abnormal brainstem auditory evoked responses (BAER). Lead (Pb) exposure has also been associated with anemia and aberrant BAER. This study investigated the relationship between HbB level and BAER wave latency and amplitude in Pb-exposed Andean children. Design and methods Sixty-six children aged 2 to 15 years (mean age: 9.1; SD: 3.3) living in Pb-contaminated villages were screened for HbB levels, blood Pb (PbB) levels and BAER latencies and amplitudes. Results The mean HbB level observed in the study group was 11.9 g/dL (SD: 1.4; range: 8.6–14.8 g/dL). The mean HbB level corrected for altitude was 10.3 g/dL (SD: 1.4; range: 6.9–13.1 g/dL), and suggestive of anemia. The mean PbB level was 49.3 ?g/dL (SD: 30.1; range: 4.4–119.1 ?g/dL) and indicative of Pb poisoning. Spearman Rho correlation analyses revealed significant associations between the BAER absolute latencies and HbB level, indicating that as the HbB level decreased, the BAER wave latency increased. Children with low HbB levels (?11 g/dL) showed significantly prolonged absolute latencies of waves I, II, III, IV and V compared to the children with normal HbB levels. Although a significant relationship between HbB and BAER waves was observed, no significant associations between PbB level and BAER parameters were found. Conclusion Low hemoglobin levels may diminish auditory sensory-neural function, and is therefore an important variable to consider when assessing BAER in children with anemia and/or Pb exposure. PMID:22735387

Counter, S. Allen; Buchanan, Leo H.; Ortega, Fernando

2012-01-01

55

Effects of vigabatrin on evoked potentials in epileptic patients  

PubMed Central

1 Somatosensory (SEP) brainstem auditory (BAEP) and visual (VEP) evoked potentials were determined before and after add-on administration of vigabatrin (GVG) in patients with epilepsy. 2 At pre-treatment assessment SEP and BAEP parameters were usually found to be within normal limits, while P100 latencies of the VEP were abnormally prolonged in a considerable proportion of patients. 3 In a double-blind, placebo-controlled trial in 22 patients GVG (1-3 g day-1 stratified according to body weight) given for 7 weeks did not modify any of the evoked potential parameters evaluated. 4 Eighteen patients were evaluated prospectively at regular intervals during long-term GVG (2-4 g day-1) therapy with a mean follow up of 24 months (range 13-42 months). SEP, BAEP and especially VEP parameters showed some interindividual variability, but the within patient variation was relatively small. No consistent important changes were seen in association with GVG, although a possible trend towards a shortening of BAEP latencies and P100 latencies was observed. 5 The relevance of these findings with respect to GVG safety is discussed. PMID:2757911

Cosi, V.; Callieco, R.; Galimberti, C. A.; Manni, R.; Tartara, A.; Mumford, J.; Perucca, E.

1989-01-01

56

Auditory and visual evoked potentials during hyperoxia  

NASA Technical Reports Server (NTRS)

Experimental study of the auditory and visual averaged evoked potentials (AEPs) recorded during hyperoxia, and investigation of the effect of hyperoxia on the so-called contingent negative variation (CNV). No effect of hyperoxia was found on the auditory AEP, the visual AEP, or the CNV. Comparisons with previous studies are discussed.

Smith, D. B. D.; Strawbridge, P. J.

1974-01-01

57

The mouse visually evoked potential : neural correlates and functional applications  

E-print Network

The visually evoked potential (VEP) is a local field potential (LFP) evoked in visual cortex in response to visual stimuli. Unlike extracellular single unit recordings, which allow us to probe the function of single spiking ...

Muhammad, Rahmat

2009-01-01

58

Startle evoked movement is delayed in older adults: implications for brainstem processing in the elderly  

PubMed Central

Abstract Little attention has been given to how age affects the neural processing of movement within the brainstem. Since the brainstem plays a critical role in motor control throughout the whole body, having a clear understanding of deficits in brainstem function could provide important insights into movement deficits in older adults. A unique property of the startle reflex is its ability to involuntarily elicit planned movements, a phenomenon referred to as startReact. The noninvasive startReact response has previously been used to probe both brainstem utilization and motor planning. Our objective was to evaluate deficits in startReact hand extension movements in older adults. We hypothesized that startReact hand extension will be intact but delayed. Electromyography was recorded from the sternocleidomastoid (SCM) muscle to detect startle and the extensor digitorum communis (EDC) to quantify movement onset in both young (24 ± 1) and older adults (70 ± 11). Subjects were exposed to a startling loud sound when prepared to extend their hand. Trials were split into those where a startle did (SCM+) and did not (SCM?) occur. We found that startReact was intact but delayed in older adults. SCM+ onset latencies were faster than SCM? trials in both the populations, however, SCM+ onset latencies were slower in older adults compared to young (? = 8 msec). We conclude that the observed age?related delay in the startReact response most likely arises from central processing delays within the brainstem. PMID:24907294

Tresch, Ursina A.; Perreault, Eric J.; Honeycutt, Claire F.

2014-01-01

59

Somatosensory evoked potentials in the ventrolateral thalamus.  

PubMed

Within the target area (VL) used for the stereotactic treatment of parkinsonian tremor and spasmodic torticollis, electrical stimulation as well as recording of somatosensory evoked potential (SEP) was performed. The effects of stimulation in the target area are facilitation of muscle tone showing some degree of somatotopic distribution. The recorded SEPs indicate a projection of an afferent system (probably of muscle afferents) to the target area. We assume that the target area is a relay station involved in the control of muscle tone. The interruption of muscle afferents in combination with the correct somatotopic localization of the lesion is important for the therapeutic efficacy in parkinsonian tremor and spasmodic torticollis. PMID:3310878

Birk, P; Riescher, H; Struppler, A; Keidel, M

1986-01-01

60

Far-field brainstem responses evoked by vestibular and auditory stimuli exhibit increases in interpeak latency as brain temperature is decreased  

NASA Technical Reports Server (NTRS)

The effect of decreasing of brain temperature on the brainstem auditory evoked response (BAER) in rats was investigated. Voltage pulses, applied to a piezoelectric crystal attached to the skull, were used to evoke stimuli in the auditory system by means of bone-conducted vibrations. The responses were recorded at 37 C and 34 C brain temperatures. The peaks of the BAER recorded at 34 C were delayed in comparison with the peaks from the 37 C wave, and the later peaks were more delayed than the earlier peaks. These results indicate that an increase in the interpeak latency occurs as the brain temperature is decreased. Preliminary experiments, in which responses to brief angular acceleration were used to measure the brainstem vestibular evoked response (BVER), have also indicated increases in the interpeak latency in response to the lowering of brain temperature.

Hoffman, L. F.; Horowitz, J. M.

1984-01-01

61

! !-q ~ i,. Altered Peripheral and Brainstem Auditory Function in Aged Rats  

E-print Network

! !-q ~ i,. BRE 11137 Altered Peripheral and Brainstem Auditory Function in Aged Rats GREGORY V to changes in peripheral auditory structures, changes in the rostral auditory brainstem ac- company age be assessed by re- cording the brainstem auditory evoked potential (BAEP). The BAEP is composed of a series

Knight, Robert T.

62

Chirp-modulated visual evoked potential as a generalization of steady state visual evoked potential.  

PubMed

Visual evoked potentials (VEPs) are of great concern in cognitive and clinical neuroscience as well as in the recent research field of brain-computer interfaces (BCIs). In this study, a chirp-modulated stimulation was employed to serve as a novel type of visual stimulus. Based on our empirical study, the chirp stimuli visual evoked potential (Chirp-VEP) preserved frequency features of the chirp stimulus analogous to the steady state evoked potential (SSVEP), and therefore it can be regarded as a generalization of SSVEP. Specifically, we first investigated the characteristics of the Chirp-VEP in the time-frequency domain and the fractional domain via fractional Fourier transform. We also proposed a group delay technique to derive the apparent latency from Chirp-VEP. Results on EEG data showed that our approach outperformed the traditional SSVEP-based method in efficiency and ease of apparent latency estimation. For the recruited six subjects, the average apparent latencies ranged from 100 to 130 ms. Finally, we implemented a BCI system with six targets to validate the feasibility of Chirp-VEP as a potential candidate in the field of BCIs. PMID:22183443

Tu, Tao; Xin, Yi; Gao, Xiaorong; Gao, Shangkai

2012-02-01

63

Identification of Diagnostic Evoked Response Potential Segments in Alzheimer's Disease  

E-print Network

#12;Identification of Diagnostic Evoked Response Potential Segments in Alzheimer's Disease James Evoked response potentials (ERPs) to brief flashes of light were analyzed for constituent features that could be used to distinguish individuals with Alzheimer's disease (AD, n 15) from matched control

Granger, Richard H.

64

The P300 in pain evoked potentials.  

PubMed

Pain evoked potentials (EPs) have been used in the last two decades as means of obtaining objective measures of pain, in clinical and experimental setups. The possibility that the pain EP wave contains elements of the endogenous P300 potential rather than being a neurophysiological correlate of pain has been raised by a number of authors, but the issue has not been resolved. In this study, two experiments were performed to study the effect of nonmodality-specific factors on the laser EP: (1) a stimulus attend as opposed to a stimulus-ignore condition and (2) counterbalanced oddball and task P300 stimulus presentations. The latter was to permit full examination of the separate and combined influences of each condition on the EP. Stimuli were given to the radial hand of 10 healthy volunteers using a CO2 laser. The positive component of the laser EP was affected by both manipulations relating to (1) attention (P = 0.0146) and (2) the frequency condition (P = 0.003) in the P300 paradigm. The task condition in the second paradigm did not affect the positive wave on its own, although its effect was visible in interaction with frequency (P = 0.033). In conclusion, although the presence of a somatic component in the laser EP cannot be rules out, we suggest that the laser EP contains a definite non-modality-specific P300 component, and is not a pure neurophysiological correlate of pain intensity. PMID:8857630

Zaslansky, R; Sprecher, E; Tenke, C E; Hemli, J A; Yarnitsky, D

1996-07-01

65

The effects of aggressive vs. conservative phototherapy on the brainstem auditory evoked responses of extremely-low-birth-weight infants  

PubMed Central

INTRODUCTION This study was a two-center, stratified, parallel-group randomized trial comparing the effects of aggressive vs. conservative phototherapy on brainstem auditory evoked response (BAER) latencies in infants with extremely low birth weight (ELBW, ? 1,000 g). RESULTS BAER latencies of 751–1,000 g birth-weight infants were shorter by 0.37 ms (95% confidence interval (CI) = 0.02, 0.73) for wave V, 0.39 ms (0.08, 0.70) for wave III, and 0.33 ms (0.01, 0.65) for wave I after aggressive phototherapy at one center. Interwave intervals did not differ significantly. Similar nonsignificant trends were recorded for 501–750 g birth-weight infants. At the other participating center, no significant differences were recorded, cautioning against overgeneralizing these results. DISCUSSION The effects of bilirubin on the auditory pathway in ELBW infants depend on a complex interaction of bilirubin exposure, newborn characteristics, and clinical management. METHODS Aggressive phototherapy was initiated sooner and continued at lower bilirubin levels than conservative phototherapy. A total of 174 ELBW infants were enrolled in the study; 111 infants were successfully tested at 35 weeks postmenstrual age (PMA); 57 died; and 6 were not successfully tested. PMID:22289854

Lasky, Robert E.; Church, Michael W.; Orlando, Mark S.; Morris, Brenda H.; Parikh, Nehal A.; Tyson, Jon E.; McDavid, Georgia E.; Oh, William; Stevenson, David K.; Van Meurs, Krisa P.; Guillet, Ronnie; Phelps, Dale L.

2012-01-01

66

Effect of middle ear effusion on the brain-stem auditory evoked response of Cavalier King Charles Spaniels.  

PubMed

Brain-stem auditory evoked responses (BAER) were assessed in 23 Cavalier King Charles Spaniels with and without middle ear effusion at sound intensities ranging from 10 to 100 dB nHL. Significant differences were found between the median BAER threshold for ears where effusions were present (60 dB nHL), compared to those without (30 dB nHL) (P=0.001). The slopes of latency-intensity functions from both groups did not differ, but the y-axis intercept when the x value was zero was greater in dogs with effusions (P=0.009), consistent with conductive hearing loss. Analysis of latency-intensity functions suggested the degree of hearing loss due to middle ear effusion was 21 dB (95% confidence between 10 and 33 dB). Waves I-V inter-wave latency at 90 dB nHL was not significantly different between the two groups. These findings demonstrate that middle ear effusion is associated with a conductive hearing loss of 10-33 dB in affected dogs despite the fact that all animals studied were considered to have normal hearing by their owners. PMID:21194995

Harcourt-Brown, Thomas R; Parker, John E; Granger, Nicolas; Jeffery, Nick D

2011-06-01

67

Auditory evoked potential measurements in elasmobranchs  

NASA Astrophysics Data System (ADS)

Auditory evoked potentials (AEP) were first used to examine hearing in elasmobranchs by Corwin and Bullock in the late 1970s and early 1980s, marking the first time AEPs had been measured in fishes. Results of these experiments identified the regions of the ear and brain in which sound is processed, though no actual hearing thresholds were measured. Those initial experiments provided the ground work for future AEP experiments to measure fish hearing abilities in a manner that is much faster and more convenient than classical conditioning. Data will be presented on recent experiments in which AEPs were used to measure the hearing thresholds of two species of elasmobranchs: the nurse shark, Ginglymostoma cirratum, and the yellow stingray, Urobatis jamaicencis. Audiograms were analyzed and compared to previously published audiograms obtained using classical conditioning with results indicating that hearing thresholds were similar for the two methods. These data suggest that AEP testing is a viable option when measuring hearing in elasmobranchs and can increase the speed in which future hearing measurements can be obtained.

Casper, Brandon; Mann, David

2005-04-01

68

Finding physiological responses in vestibular evoked potentials.  

PubMed

Vestibular prostheses are regarded as a promising tool to restore lost sensation in patients with vestibular disorders. These prostheses often electrically stimulate the vestibular nerve and stimulation efficacy is evaluated by measuring the vestibulo-ocular reflex (VOR). However, eye movement recording as intuitive metric of vestibular functionality is difficult to obtain outside the laboratory environment, and hence not available as an error signal in a closed-loop prosthesis. Recently we investigated vestibular evoked potentials (VEPs) by stimulating and recording in the same semicircular canal of a guinea pig. Here we studied the correlation between VOR and one region of VEP. We further analyzed a second portion of VEP, where vestibular nerve activity should occur using rectified bin integration (RBI). To this end, stimulation artifact was significantly reduced by hardware and software approaches. We found a high VEP-VOR correlation (R-squared=0.86), suggesting that VEP could substitute VOR as metric of vestibular function. Differences between below and above vestibular threshold stimulation were seen for the second portion of VEP. Further investigations are required to determine the specific parts of VEP that accurately represents vestibular function(s). PMID:22254790

Nguyen, T A K; Kogler, V; DiGiovanna, J; Micera, S

2011-01-01

69

Auditory evoked potential measurements with cetaceans  

NASA Astrophysics Data System (ADS)

Auditory evoked potentials (AEPs) allow researchers to measure the hearing abilities of animals that would be difficult or impossible to train for behavioral measurements of hearing. The hearing abilities of live-stranded cetaceans and wild dolphins can only be made with AEP techniques. In these situations, time with the animal is often restricted to an hour or less, and there is often little control over the acoustic environment in which the tests are performed. AEP measurements may be made while the animals are in air or in shallow pools. For cetaceans in air, sounds are typically presented with a suction cup jawphone. For cetaceans in water, sounds may be presented in a direct field (with the transducer located at some distance from the test subject) or with a jawphone. In each of these situations it is important to understand how thresholds derived from AEP measurements compare with behavioral hearing measurements. Examples of AEP measurements from wild and live-stranded cetaceans are presented to illustrate their usefulness and the constraints under which these measurements must be made. AEP measurements from bottlenose dolphins in air and in water are also compared with their behavioral audiograms.

Mann, David; Cook, Mandy; Bauer, Gordon; Fellner, Wendi; Wells, Randy

2005-04-01

70

Visual evoked potentials in primary hypertension.  

PubMed

Functional integrity of sensory pathways in the brain has not been well documented in hypertension. It is suggested that vascular endothelial changes including hyalinisation during hypertension may lead to demyelination in the vulnerable areas of the brain. Since optic nerve is considered to be part of brain hence the present study was done to find out if visual pathways are involved in hypertension. Transient pattern reversal visual evoked potentials (VEPs) from 01, 02 scalp regions were recorded in 23 primary hypertensive patients and compared with 14 normotensive control. Of these, six patients showed delayed P1 latencies beyond 99% tolerance limit i.e. Mean + 3 SD of normal. The remaining 17 had latencies of all positive (P1-P3) and negative (N1-N3) waves comparable to those of the control group. Correlation Coefficient worked out, showed significant correlation between systolic BP and P1 latency in the control group only. No other parameter showed any correlation with P1 latency & amplitude in both the groups. These findings show that fluctuations of BP in normotensive subjects have correlation with P1 latency. This correlation ceased to exist in hypertensive patients and abnormality in P1 latency of VEP was detected in 26% cases. PMID:9142561

Tandon, O P; Ram, D

1997-04-01

71

Visual evoked potential study in slow learners.  

PubMed

Slow learners are individuals with low achievement and comparably low IQ scores. It may be a symptom reflecting a larger underlying problem in them. Sensory neural processing of visual information can be one of the contributory factors for their underachievement. The present study was undertaken to examine the integrity and function of visual pathway by means of Visual Evoked Potential (VEP). Pattern reversal VEP was performed on seventeen slow learners. Fifteen age and sex matched children with good school performance and normal IQ were taken as controls. There was significant prolongation of N75 component of VEP in slow learners. The latencies of P100 and N145 were also increased but could not reach the level of significance. Our findings are suggestive of the presence of a weaker VEP response in slow learners indicative of a deficit early in the visual processing. There is some abnormality in the geniculate afferents to V1 which is consistent with a defect in the magnocellular pathway at the level of Visual Area 1 or earlier. PMID:20509326

Khaliq, Farah; Anjana, Yumnam; Vaney, Neelam

2009-01-01

72

Vestibular evoked myogenic potentials in Bell's palsy.  

PubMed

The aim of the present study was to evaluate vestibular nerve involvement in patients with Bell's palsy with ocular and cervical vestibular evoked myogenic potentials (oVEMP and cVEMP). Ten patients who were diagnosed with Bell's palsy and ten healthy controls were included. All patients underwent VEMP recordings within 6 days after their initial presentation. Patients with Bell's palsy had greater oVEMP asymmetry ratio comparing to healthy controls (-38.4 ± 28.7 % vs -1.3 ± 19.3 %, p = 0.005). As well N10 latencies of the oVEMP response were prolonged comparing to healthy controls (11.575 vs 9.72 ms). There was no difference in cVEMP asymmetry ratio or latencies between groups. We found no correlation between House-Brackmann grading scale and oVEMP asymmetry ratio (r = 0.003, p = 0.994). There are three possible explanations for increased oVEMP amplitudes on the affected side: (1) oVEMP response on the ipsilateral eye could be contaminated by facial nerve activity (blink reflex); (2) the amplitude of N10-P33 could be affected through the stapedial reflex; and (3) increased oVEMP amplitude could be the consequence of the vestibular nerve dysfunction itself, with prolonged latencies of the N10 oVEMP further supporting this explanation. The results of this study indicate possible involvement of the superior branch of the vestibular nerve in patients with Bell's palsy. PMID:24916836

Krbot Skoric, Magdalena; Adamec, Ivan; Habek, Mario

2014-10-01

73

Somatosensory Evoked Potential Findings in Ankylosing Spondylitis  

PubMed Central

Objective: Somatosensory evoked potential (SSEP) abnormalities were reported in patients with ankylosing spondylitis (AS). This study aimed to investigate SSEP abnormalities and its relation with clinical findings in AS patients. Materials and Methods: The study included 26 patients with AS and 17 age-matched health volunteers (Control for SSEP). Median nerve SSEP findings were normal in all AS cases. Results: However, delayed latency and/or very low amplitude of tibial nerve SSEP was found in 20 (76.9%) AS patients. There were significant correlations between tibial SSEP latency and disease duration (R=0.433 to 0.635). There was also an inverse correlation between tibial SSEP amplitude and disease duration (R=?0.429, p=0.047). Serum estradiol level, hip total bone mineral density, The Bath Ankylosing Spondylitis Functional Index (BASFI) score and Beck depression score were significantly lower in AS patients with SSEP abnormalities (37.3±10.8 pg/mL, 0.916±0.123 g/cm2, 35.0±27.9, 12.8±8.4, respectively) than in AS patients without SSEP abnormalities (53.7±12.3 pg/mL, 1.103±0.197 g/cm2, 64.8±15.5, 24.8±10.1, respectively). Conclusion: Significant inverse correlations between SSEP latencies and dehydroepiandrosterone sulphate (DHEAS) levels were found (R=?0.400 to ?0.713). There were also significant inverse correlation between SSEP latencies and DHEAS/oestrogen index (R=?0.596 to ?0.868), and between SSEP latencies and DHEAS/Progesterone index (R=?0.467 to ?0.685). As a conclusion, this study indicates that tibial nerve SSEP abnormalities are common in patients with AS and there are significant correlations between clinical findings of AS and SSEP abnormalities. PMID:25610293

Cidem, Muharrem; Sahin, Zerrin; Aydin, Teoman; Aysal, Fikret

2014-01-01

74

Auditory evoked potentials: predicting speech therapy outcomes in children with phonological disorders  

PubMed Central

OBJECTIVES: This study investigated whether neurophysiologic responses (auditory evoked potentials) differ between typically developed children and children with phonological disorders and whether these responses are modified in children with phonological disorders after speech therapy. METHODS: The participants included 24 typically developing children (Control Group, mean age: eight years and ten months) and 23 children clinically diagnosed with phonological disorders (Study Group, mean age: eight years and eleven months). Additionally, 12 study group children were enrolled in speech therapy (Study Group 1), and 11 were not enrolled in speech therapy (Study Group 2). The subjects were submitted to the following procedures: conventional audiological, auditory brainstem response, auditory middle-latency response, and P300 assessments. All participants presented with normal hearing thresholds. The study group 1 subjects were reassessed after 12 speech therapy sessions, and the study group 2 subjects were reassessed 3 months after the initial assessment. Electrophysiological results were compared between the groups. RESULTS: Latency differences were observed between the groups (the control and study groups) regarding the auditory brainstem response and the P300 tests. Additionally, the P300 responses improved in the study group 1 children after speech therapy. CONCLUSION: The findings suggest that children with phonological disorders have impaired auditory brainstem and cortical region pathways that may benefit from speech therapy. PMID:24626949

Leite, Renata Aparecida; Wertzner, Haydée Fiszbein; Gonçalves, Isabela Crivellaro; Magliaro, Fernanda Cristina Leite; Matas, Carla Gentile

2014-01-01

75

doi:10.1093/brain/awh367 Brain (2005), 128, 417423 Correlation between brainstem and cortical auditory  

E-print Network

doi:10.1093/brain/awh367 Brain (2005), 128, 417­423 Correlation between brainstem and cortical relationship between brainstem and cortical auditory processing was shown to be abnormal in children with language-based learning problems (LP). Auditory evoked potentials were used to investigate brainstem

76

28 BrainResearch, 348 (1985)28-35 Altered Peripheral and Brainstem Auditory Function in Aged Rats  

E-print Network

28 BrainResearch, 348 (1985)28-35 Elsevier BRE 11137 Altered Peripheral and Brainstem Auditory-- hearing loss-- rat A technique for conducting free-field brainstem auditory evoked potential (BAEP that in addition to changes in peripheral auditory structures, changes in the rostral auditory brainstem ac

Knight, Robert T.

77

Evoked response study tool: a portable, rugged system for single and multiple auditory evoked potential measurements.  

PubMed

Although the potential of using portable auditory evoked potential systems for field testing of stranded cetaceans has been long recognized, commercial systems for evoked potential measurements generally do not possess the bandwidth required for testing odontocete cetaceans and are not suitable for field use. As a result, there have been a number of efforts to develop portable evoked potential systems for field testing of cetaceans. This paper presents another such system, called the evoked response study tool (EVREST). EVREST is a Windows-based hardware/software system designed for calibrating sound stimuli and recording and analyzing transient and steady-state evoked potentials. The EVREST software features a graphical user interface, real-time analysis and visualization of recorded data, a variety of stimulus options, and a high level of automation. The system hardware is portable, rugged, battery-powered, and possesses a bandwidth that encompasses the audible range of echolocating odontocetes, making the system suitable for field testing of stranded or rehabilitating cetaceans. PMID:19603907

Finneran, James J

2009-07-01

78

KETAMINE ALTERS RAT FLASH EVOKED POTENTIALS (JOURNAL VERSION)  

EPA Science Inventory

Discovering the neurotransmitters involved in the generation of flash evoked potentials (FEPs) would enhance the use of FEPs in screening for and assessment of neurological damage. Recent evidence suggests that the excitatory amino acids, glutamate and aspartate, may be transmitt...

79

Vestibular Evoked Myogenic Potentials : physiology, variability, and statistical characteristics  

E-print Network

Vestibular Evoked Myogenic Potentials (VEMPs) are electrical signals recorded from the skin overlying skeletal muscles of the head and neck in response to high-intensity acoustic stimuli. VEMPs have been observed in stimulus ...

Prakash, Srinivasamurthy Ravi

2009-01-01

80

Auditory Brainstem Correlates of Perceptual Timing Deficits  

E-print Network

Auditory Brainstem Correlates of Perceptual Timing Deficits Krista L. Johnson, Trent G. Nicol. Speech-evoked brainstem responses were analyzed across groups to measure the neural integrity of stimulus in structures as early as the auditory brainstem. Thus, speech- evoked brainstem responses are a biological

81

Vestibular receptors contribute to cortical auditory evoked potentials?  

PubMed Central

Acoustic sensitivity of the vestibular apparatus is well-established, but the contribution of vestibular receptors to the late auditory evoked potentials of cortical origin is unknown. Evoked potentials from 500 Hz tone pips were recorded using 70 channel EEG at several intensities below and above the vestibular acoustic threshold, as determined by vestibular evoked myogenic potentials (VEMPs). In healthy subjects both auditory mid- and long-latency auditory evoked potentials (AEPs), consisting of Na, Pa, N1 and P2 waves, were observed in the sub-threshold conditions. However, in passing through the vestibular threshold, systematic changes were observed in the morphology of the potentials and in the intensity dependence of their amplitude and latency. These changes were absent in a patient without functioning vestibular receptors. In particular, for the healthy subjects there was a fronto-central negativity, which appeared at about 42 ms, referred to as an N42, prior to the AEP N1. Source analysis of both the N42 and N1 indicated involvement of cingulate cortex, as well as bilateral superior temporal cortex. Our findings are best explained by vestibular receptors contributing to what were hitherto considered as purely auditory evoked potentials and in addition tentatively identify a new component that appears to be primarily of vestibular origin. PMID:24321822

Todd, Neil P.M.; Paillard, Aurore C.; Kluk, Karolina; Whittle, Elizabeth; Colebatch, James G.

2014-01-01

82

CHRONIC DIETARY EXPOSURE WITH INTERMITTENT SPIKE DOSES OF CHLORPYRIFOS FAILS TO ALTER BRAINSTEM AUDITORY EVOKED RESPONSE (BAERS) IN RATS.  

EPA Science Inventory

Human exposure to pesticides is often characterized by chronic low level exposure with intermittent spiked higher exposures. Cholinergic transmission is involved in auditory structures in the periphery and the brainstem and is altered following chlorpyrifos exposure. This study e...

83

Enhanced neuronal excitability in adult rat brainstem causes widespread repetitive brainstem depolarizations with cardiovascular consequences  

PubMed Central

The brainstem of the adult rat is relatively resistant to spreading depolarization (SD) but after enhancement of excitability SD can be evoked by local application of KCl. In the present experiments, we observed that the enhanced excitability even triggers prolonged periods of repetitive depolarizations (RDs), which elicit significant cardiovascular changes. In contrast to KCl-evoked SDs with amplitudes of ?24?mV and spreading velocity of 4?mm/min, spontaneous RDs had amplitudes of 7 to 12?mV, propagated up to 30 times faster than KCl-evoked SDs, and depolarized larger brainstem areas including the contralateral side. Similarly as SD, RDs depended on glutamatergic neurotransmission and were blocked by MK-801 or by the calcium channel blocker agatoxin. They depended on sodium channels and were blocked by tetrodotoxin. Functionally, the invasion of RDs into the spinal trigeminal and other nuclei evoked bursts of action potentials, indicating that specific neuronal systems are affected. In fact, during episodes of RDs the blood pressure and the local blood flow at the surface of the brainstem and the cortex increased substantially. Brainstem RDs did not propagate into the cerebral cortex. We propose to consider brainstem RPs as a pathophysiological mechanism whose significance for brainstem disease states should be further explored. PMID:22453631

Richter, Frank; Bauer, Reinhard; Ebersberger, Andrea; Lehmenkühler, Alfred; Schaible, Hans-Georg

2012-01-01

84

Attempts to elicit an evoked potential in the pigeon using a magnetic field stimulus  

E-print Network

evoked potentials from pigeon ?6 by decreasing stimulus intensity 9) Effects on pigeon ?6 auditory evoked potential by varying stimulus repetition rate 50 51 10) Auditory evoked potentials from pigeon ?6 from tone stimuli of varying frequencies 52...-up , and procedure was tested by successfully recording auditory evoked potentials from the scalps of ten anesthetized pigeons. It was found that the auditory evoked potentials were of very short onset latency and low in amplitude, although they were very...

Randolph, William Robert

1984-01-01

85

Single-trial evoked potential estimation using wavelets.  

PubMed

In this paper we present conventional and translation-invariant (TI) wavelet-based approaches for single-trial evoked potential estimation based on intracortical recordings. We demonstrate that the wavelet-based approaches outperform several existing methods including the Wiener filter, least mean square (LMS), and recursive least squares (RLS), and that the TI wavelet-based estimates have higher SNR and lower RMSE than the conventional wavelet-based estimates. We also show that multichannel averaging significantly improves the evoked potential estimation, especially for the wavelet-based approaches. The excellent performances of the wavelet-based approaches for extracting evoked potentials are demonstrated via examples using simulated and experimental data. PMID:16987507

Wang, Zhisong; Maier, Alexander; Leopold, David A; Logothetis, Nikos K; Liang, Hualou

2007-04-01

86

Stimulator with arbitrary waveform for auditory evoked potentials  

NASA Astrophysics Data System (ADS)

The technological improvement helps many medical areas. The audiometric exams involving the auditory evoked potentials can make better diagnoses of auditory disorders. This paper proposes the development of a stimulator based on Digital Signal Processor. This stimulator is the first step of an auditory evoked potential system based on the ADSP-BF533 EZ KIT LITE (Analog Devices Company - USA). The stimulator can generate arbitrary waveform like Sine Waves, Modulated Amplitude, Pulses, Bursts and Pips. The waveforms are generated through a graphical interface programmed in C++ in which the user can define the parameters of the waveform. Furthermore, the user can set the exam parameters as number of stimuli, time with stimulation (Time ON) and time without stimulus (Time OFF). In future works will be implemented another parts of the system that includes the acquirement of electroencephalogram and signal processing to estimate and analyze the evoked potential.

Martins, H. R.; Romão, M.; Plácido, D.; Provenzano, F.; Tierra-Criollo, C. J.

2007-11-01

87

Sensory, cognitive and motor assessment of children with poor academic performance: an auditory evoked potential study.  

PubMed

The present study aims to evaluate the auditory sensory process in the brainstem, thalamocortical and cortical areas by using auditory evoked potentials [auditory brainstem response (ABR), mid latency response (MLR) and slow vertex response (SVR)], cognitive functions by P300 and motor response by reaction time in children with poor academic performance. Thirty children between 6-12 years of age were selected as subjects on the basis of poor academic school records. While thirty children with good academic performance served as controls. The recordings were done using a computerized evoked potential recorder by 10-20 electrode placement system. There was no difference in the anthropometric parameters and IQ of the two groups. There was a significant increase in latency of waves II, III, IV and V, and Inter-peak latency I-V of ABR in poor performer females. All the component waves of MLR and SVR showed increased latency in the subjects but could not reach the level of significance. There was a significant increase in latencies of P300 at Cz and Pz electrode positions with no change in amplitude in poor performer females. The reaction time was also increased in the poor performer females as compared to the controls. The latencies of all the waves of ABR, P300 and reaction time are also increased in male poor performers as compared to male controls but could not reach the level of significance. The conduction of impulses is slower in pontine and midbrain auditory pathway along with inefficient cortical processing of task relevant stimuli and motor response in female children having poor academic performance. PMID:21409863

Khaliq, Farah; Alam, Kaushal Kumar; Vaney, Neelam; Singh, T B

2010-01-01

88

Chronic Network Stimulation Enhances Evoked Action Potentials  

PubMed Central

Neurons cultured on multielectrode arrays almost always lack external stimulation except during the acute experimental phase. We have investigated the effects of chronic stimulation during the course of development in cultured hippocampal neural networks by applying paired pulses at half of the electrodes for 0, 1, or 3 hr/day for 8 days. Spike latencies increased from 4 to 16 ms as the distance from the stimulus increased 200–1700 ?m, suggesting an average of 4 synapses over this distance. Compared to no chronic stimulation, our results indicate that, chronic stimulation increased evoked spike counts per stimulus by 50% at recording sites near the stimulating electrode and increased the instantaneous firing rate. On trials where both pulses elicited responses, spike count was 40–80% higher than when only one of the pulses elicited a response. In attempts to identify spike amplitude plasticity, we found mainly amplitude variation with different latencies suggesting recordings from neurons with different identities. These data suggest plastic network changes induced by chronic stimulation that enhance the reliability of information transmission and the efficiency of multisynaptic network communication. PMID:20083862

Ide, A. N.; Andruska, A.; Boehler, M.; Wheeler, B. C.; Brewer, G. J.

2013-01-01

89

Trigeminal somatosensory evoked potentials: a normal value study.  

PubMed

Normal somatosensory evoked potentials were obtained from the lower lip of 40 volunteers. Efforts were made to exclude artefact. A consistent triphasic wave form of three peaks and troughs was defined. There were greater variations in amplitude than latency between subjects. Statistically, one side of the lower lip can be used as a control for the contralateral side, but it may not be possible to have reliable normal values between subjects. Somatosensory evoked potentials may however represent an objective method of evaluating trigeminal sensory nerve function. PMID:1452868

Pogrel, M A; Mouhabaty, D; Dodson, T; Rampil, I; Grecco, M

1992-10-01

90

[Clinical application of pain-related evoked potentials].  

PubMed

Pain-related evoked potentials (PREPs) represent a novel method for the evaluation of peripheral and central nociceptive pathways, e.g. in the diagnosis of small fiber neuropathy (SFN) or after therapeutic interventions for headache. Compared to contact heat-evoked and laser-evoked potentials, recording of PREPs is less stressful for the subjects and technically less demanding. The clinical usefulness of PREPs has been described for SFN associated with diabetes, HIV and hepatitis C infections as well as in headache and facial pain disorders. They have also been evaluated after interventional methods, such as direct current stimulation (tDCS). The article reviews and discusses the advantages and pitfalls of this technique in the context of recent clinical studies as compared to other paradigms of peripheral electrical stimulation and delineates perspectives and possible indications. PMID:22134376

Hansen, N; Obermann, M; Uçeyler, N; Zeller, D; Mueller, D; Yoon, M S; Reiners, K; Sommer, C; Katsarava, Z

2012-02-01

91

EVOKED POTENTIALS, PHYSIOLOGICAL METHODS WITH HUMAN APPLICATIONS  

EPA Science Inventory

A number of tests and test batteries have been developed and implemented for detecting potential neurotoxicity in humans. n some cases test results may suggest specific dysfunction. hile tests in laboratory animals are often used to project the potential for adverse health effect...

92

Human auditory evoked potentials. II - Effects of attention  

NASA Technical Reports Server (NTRS)

Attention directed toward auditory stimuli, in order to detect an occasional fainter 'signal' stimulus, caused a substantial increase in the N1 (83 msec) and P2 (161 msec) components of the auditory evoked potential without any change in preceding components. This evidence shows that human auditory attention is not mediated by a peripheral gating mechanism. The evoked response to the detected signal stimulus also contained a large P3 (450 msec) wave that was topographically distinct from the preceding components. This late positive wave could also be recorded in response to a detected omitted stimulus in a regular train and therefore seemed to index a stimulus-independent perceptual decision process.

Picton, T. W.; Hillyard, S. A.

1974-01-01

93

On hemispheric differences in evoked potentials to speech stimuli  

NASA Technical Reports Server (NTRS)

Confirmation is provided for the belief that evoked potentials may reflect differences in hemispheric functioning that are marginal at best. Subjects were right-handed and audiologically normal men and women, and responses were recorded using standard EEG techniques. Subjects were instructed to listen for the targets while laying in a darkened sound booth. Different stimuli, speech and tone signals, were used. Speech sounds were shown to evoke a response pattern that resembles that to tone or clicks. Analysis of variances on peak amplitude and latency measures showed no significant differences between hemispheres, however, a Wilcoxon test showed significant differences in hemispheres for certain target tasks.

Galambos, R.; Benson, P.; Smith, T. S.; Schulman-Galambos, C.; Osier, H.

1975-01-01

94

ONTOGENY OF FLASH-EVOKED POTENTIALS IN UNANESTHETIZED RATS  

EPA Science Inventory

The effects of age and stimulation frequency (0.2/sec, 1.0/sec, 2.0/sec, or 4.0/sec) on flash evoked potentials (FEPs) were investigated in awake, unsedated, unrestrained rats. Animals were tested daily from postnatal day (PND) 8 through PND 20, and every three or four days there...

95

Cortical Auditory Evoked Potentials in Unsuccessful Cochlear Implant Users  

ERIC Educational Resources Information Center

In some cochlear implant users, success is not achieved in spite of optimal clinical factors (including age at implantation, duration of rehabilitation and post-implant hearing level), which may be attributed to disorders at higher levels of the auditory pathway. We used cortical auditory evoked potentials to investigate the ability to perceive…

Munivrana, Boska; Mildner, Vesna

2013-01-01

96

Myelin Deterioration in Twitcher Mice: Motor Evoked Potentials and Magnetic  

E-print Network

of the Twitcher mouse, the murine model for globoid cell leukodystrophy (GLD). GLD is a lysosomal storage disorder resonance imaging (MRI) and motor evoked potentials (MEPs) for monitoring disease progression within the CNS Deficiency of the lysosomal enzyme galactocerebro- sidase (GALC; EC 3.2.1.46) leads to globoid cell leuko

Bongarzone, Ernesto R.

97

Brain-Computer Interfaces Based on Visual Evoked Potentials  

Microsoft Academic Search

Recently, electroencephalogram (EEG)-based brain- computer interfaces (BCIs) have become a hot spot in the study of neural engineering, rehabilitation, and brain science. In this article, we review BCI systems based on visual evoked potentials (VEPs). Although the performance of this type of BCI has already been evaluated by many research groups through a variety of laboratory demonstrations, researchers are still

Yijun Wang; Xiaorong Gao; Bo Hong; Chuan Jia; Shangkai Gao

2008-01-01

98

Ocular vestibular evoked myogenic potentials in patients with acoustic neuroma.  

PubMed

To assess the usefulness of vestibular testing in patients with acoustic neuroma, considering two main aspects: to compare diagnostic sensitivity of the current vestibular tests, especially considering ocular vestibular evoked myogenic potentials (OVEMPs) and to identify pre-operative localization of the tumor (inferior vestibular nerve vs. superior vestibular nerve) only with the help of vestibular electrophysiological data. Twenty-six patients with unilateral acoustic neuroma (mainly intracanalicular type) were studied with a full audio-vestibular test battery (pure tone and speech audiometry, caloric bithermal test, vibration-induced nystagmus test (VIN), cervical and OVEMPs). 18 patients (69 %) showed abnormal caloric responses. 12 patients (46.2 %) showed a pattern of VIN test suggestive of vestibular asymmetry. 16 patients (61.5 %) showed abnormal OVEMPs (12 only to AC, 4 both to AC and BC). 10 patients (38.5 %) showed abnormal cervical vestibular evoked myogenic potentials (5 both to AC and BC, 5 only to AC). In one case, results of vestibular evoked potentials and caloric test were confirmed by intra-operative and post-operative findings. Results of electrophysiological tests in AN patients could be helpful for planning the proper surgical approach, considering that sensitivity of every exam is quite low in intracanalicular lesion; clinical data allow a better interpretation of vestibular evoked myogenic potentials. PMID:22526579

Piras, Gianluca; Brandolini, Cristina; Castellucci, Andrea; Modugno, Giovanni Carlo

2013-02-01

99

B Auditory brainstem potentials in sons of alcoholic fathers. Alcohol Clin Exp Res  

E-print Network

With the use of event-related brain potentials we have obsewed sensory as well as cognitive deficits in abstinent alcoholics. By recording auditory brainstem potentials (BSP) from abstinent alcoholics we demonstrated significant delays in brainstem transmission time. We have also repotted that P3 amplitudes are significantly reduced in abstinent alcoholics compared to control subjects. Although the neurophysiological deficits obsewed in abstinent alcoholics are presumed to be alcohol-related effects, it is possible that some of these deficits may exist prior to alcohol exposure, and may be present in subjects at high risk for alcoholism. We have recently obsewed significantly reduced P3 components in young sons of alcoholics similar to those obsewed in abstinent alcoholics. In the present study, we examined auditory BSPs in young boys at high risk for alcoholism and matched controls. We found no statistically significant difference in brainstem transmission time between

Henri Begleiter; Bernice Porjesz; Bernard Bihari

1987-01-01

100

Motor Evoked Potentials in Cerebral Aneurysm Surgery.  

PubMed

While the development and implementation of HIV-related online interventions has expanded, few have been tailored for women or have leveraged Web 2.0's capabilities to provide social support. We conducted semi-structured interviews with 27 women with HIV at an urban community health center to understand their perspectives on the potential role of the Internet and the use of an online group format to provide social support. Data were analyzed using the constant comparative method. We identified six themes: a need for groups and increased sense of connectedness, convenience and accessibility, trust as a precondition for participating, online groups as a potential facilitator or barrier to expression, limited digital access and literacy, and privacy concerns. Overall, women were highly supportive of online group-based interventions but acknowledged the need for increased digital access and Internet navigation training. Hybrid (in-person and online) interventions may be most useful for women with HIV. PMID:25460050

Nakaji, Peter

2014-11-20

101

A portable system for marine mammal auditory-evoked potential measurements  

NASA Astrophysics Data System (ADS)

Limitations to behavioral measures of hearing sensitivity in marine mammals include the time and expense typically required to train subjects. These limitations have resulted in limited subjects and lingering questions regarding intraspecific variability. An alternative to behavioral methods is the electrophysiological method, where passive electrodes are used to measure auditory-evoked potentials (AEPs) generated by the brain in response to sound stimuli. Marine mammal AEP measurements have been limited by the complexity of the technique and the limited applicability of commercially available AEP systems. In this paper, a portable, laptop computer-based system for marine mammal AEP measurements will be presented. The system features commercial off-the-shelf components, including a data acquisition PC card, biopotential amplifier, and programmable attenuator. The system is housed in a rugged, shock-resistant case. Custom software is used to present sound stimuli, record evoked responses, and analyze the resulting data. The system has been used to measure auditory brainstem responses to clicks and tone pips and envelope following responses to amplitude-modulated tones in bottlenose dolphins. Preliminary data obtained with the system will be presented and compared to behavioral hearing measures. [Work supported by the ILIR at SPAWARSYSCEN-SD and the ONR.

Finneran, James J.; Houser, Dorian S.

2001-05-01

102

Differential effects of exogenous estrogen versus a estrogen-progesterone combination on auditory evoked potentials in menopausal women.  

PubMed

The study was undertaken to determine the differential effects of estrogen and progestin on auditory evoked responses in postmenopausal women receiving hormone replacement therapy (HRT). Forty-seven women between 45 and 70 years of age attending menopause and HRT clinic were divided into two groups. Group I included 32 women who attained natural menopause and receiving combined estrogen progestin therapy. While group II included 15 surgically menopausal women receiving only estrogen. Evoked potentials were recorded in form of auditory brainstem response (ABR), middle latency response (MLR) & slow vertex response (SVR). There was improvement of conduction in auditory pathways at the level of brainstem and thalamocortical projections as indicated by the decrease in latencies of most of the waves of ABR and/MLR after 6 months of HRT in both the groups. The conduction in association areas, as indicated by SVR, did not show a significant change. The intergroup comparison after therapy revealed a decrease in latency of wave V and I-V interpeak latency in group II indicating that only estrogen users are benefited more. Thus HRT facilitates the process of sensory conduction, which may form one of the mechanisms of improved neuropsychological functions in menopausal women on HRT. The addition of progestin to estrogen does not have a negative or potentiating effect on it. PMID:16440855

Khaliq, Farah; Tandon, Om Prakash; Goel, Neerja

2005-01-01

103

[Progress in single-trial extraction of evoked potential].  

PubMed

The robust extracting of evoked potential (EP) has become a vexed question in the process of electroencephalogram owing to the faint signal-to-noise ratio of EP. This paper presents the single trial of EP in time, transform and space field. Several methods such as adaptive filter, wavelet transform, principal component analysis (PCA) and independent component analysis (ICA) have been applied to the process of EP. PMID:19947511

Tao, Cailin; Zou, Ling; Ma, Zhenghua; Zhou, Renlai

2009-10-01

104

Evoked potentials to electrical stimulation of the facial nerve in the carp tectum mesencephali  

Microsoft Academic Search

Tectal evoked potentials to stimulation of the facial nerve, containing afferent fibers of nonolfactory chemoreception, in the carp are positive evoked potentials with a latent period of 5 to 25 msec which show no phase shift as the microelectrode is advanced to a depth of 600 µ. Depending on the amplitude and latency of evoked potentials seven active zones differing

N. E. Vasilevskaya; L. N. Stankevich

1976-01-01

105

Cortical Auditory Evoked Potentials to Acoustic Changes in Speech Stimuli in Children  

Microsoft Academic Search

Objective: To compare the maturation of speech-evoked N170 components of cortical auditory evoked potentials with that of tone-evoked N1 components. Patients and Methods: Cortical auditory evoked potentials to speech and tone stimuli were derived in 42 children from age 4 to 14 years. The N170 was derived from the difference curve of responses to monosyllabic words with initial consonant-to-vowel transitions

Peter Kummer; Martin Burger; Maria Schuster; Frank Rosanowski; Ulrich Eysholdt; Ulrich Hoppe

2007-01-01

106

Short latency vestibular evoked potentials in the chicken embryo  

NASA Technical Reports Server (NTRS)

Electrophysiological responses to pulsed linear acceleration stimuli were recorded in chicken embryos incubated for 19 or 20 days (E19/E20). Responses occurred within the first 16 ms following the stimulus onset. The evoked potentials disappeared following bilateral labyrinthectomy, but persisted following cochlear destruction alone, thus demonstrating that the responses were vestibular. Approximately 8 to 10 response peaks could be identified. The first 4 positive and corresponding negative components (early peaks with latencies < 6.0 ms) were scored and latencies and amplitudes quantified. Vestibular response latencies were significantly longer (P < 0.01) and amplitudes significantly smaller (P < 0.001) than those observed in 2-week-old birds. Mean response threshold for anesthetized embryos was -15.9dBre 1.0 g/ms, which was significantly higher (P < 0.03) than those observed in 2-week-old birds (-23.0dBre 1.0 g/ms). Latency/intensity functions (that is, slopes) were not significantly different between embryos and 2-week-old animals, but amplitude/intensity functions for embryos were significantly shallower than those for 2-week-old birds (P < 0.001). We presume that these differences reflect the refinement of sensory function that occurs following 19 to 20 days of incubation. The recording of vestibular evoked potentials provides an objective, direct and noninvasive measure of peripheral vestibular function in the embryo and, as such, the method shows promise as an investigative tool. The results of the present study form the definitive basis for using vestibular evoked potentials in the detailed study of avian vestibular ontogeny and factors that may influence it.

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

1996-01-01

107

The division of attention and the human auditory evoked potential  

NASA Technical Reports Server (NTRS)

The sensitivity of the scalp-recorded, auditory evoked potential to selective attention was examined while subjects responded to stimuli presented to one ear (focused attention) and to both ears (divided attention). The amplitude of the N1 component was found to be largest to stimuli in the ear upon which attention was to be focused, smallest to stimuli in the ear to be ignored, and intermediate to stimuli in both ears when attention was divided. The results are interpreted as supporting a capacity model of attention.

Hink, R. F.; Van Voorhis, S. T.; Hillyard, S. A.; Smith, T. S.

1977-01-01

108

Asymmetric vestibular evoked myogenic potentials in unilateral Menière patients  

PubMed Central

Vestibular evoked myogenic potentials (VEMPs) were measured in 22 unilateral Menière patients with monaural and binaural stimulation with 250 and 500 Hz tone bursts. For all measurement situations significantly lower VEMP amplitudes were on average measured at the affected side compared to the unaffected side. Unilateral Menière patients have, in contrast to normal subjects, asymmetric VEMPs, indicating a permanently affected vestibular (most likely otolith) system at the side of hearing loss. The diagnostic value of VEMP amplitude asymmetry measurement in individual patients is low, because of the large overlap of the VEMP amplitude asymmetry range for unilateral Menière patients with that for normal subjects. PMID:20665043

Wit, H. P.

2010-01-01

109

Conditioning effect of transcranial magnetic stimulation evoking motor-evoked potential on V-wave response.  

PubMed

The aim of this study was to examine the collision responsible for the volitional V-wave evoked by supramaximal electrical stimulation of the motor nerve during voluntary contraction. V-wave was conditioned by transcranial magnetic stimulation (TMS) over the motor cortex at several inter-stimuli intervals (ISI) during weak voluntary plantar flexions (n = 10) and at rest for flexor carpi radialis muscle (FCR; n = 6). Conditioning stimulations were induced by TMS with intensity eliciting maximal motor-evoked potential (MEPmax). ISIs used were ranging from -20 to +20 msec depending on muscles tested. The results showed that, for triceps surae muscles, conditioning TMS increased the V-wave amplitude (~ +250%) and the associated mechanical response (~ +30%) during weak voluntary plantar flexion (10% of the maximal voluntary contraction -MVC) for ISIs ranging from +6 to +18 msec. Similar effect was observed at rest for the FCR with ISI ranging from +6 to +12 msec. When the level of force was increased from 10 to 50% MVC or the conditioning TMS intensity was reduced to elicit responses of 50% of MEPmax, a significant decrease in the conditioned V-wave amplitude was observed for the triceps surae muscles, linearly correlated to the changes in MEP amplitude. The slope of this correlation, as well as the electro-mechanical efficiency, was closed to the identity line, indicating that V-wave impact at muscle level seems to be similar to the impact of cortical stimulation. All these results suggest that change in V-wave amplitude is a great index to reflect changes in cortical neural drive addressed to spinal motoneurons. PMID:25501438

Grosprêtre, Sidney; Martin, Alain

2014-12-01

110

A New Measure for Monitoring Intraoperative Somatosensory Evoked Potentials  

PubMed Central

Objective To propose a new measure for effective monitoring of intraoperative somatosensory evoked potentials (SEP) and to validate the feasibility of this measure for evoked potentials (EP) and single trials with a retrospective data analysis study. Methods The proposed new measure (hereafter, a slope-measure) was defined as the relative slope of the amplitude and latency at each EP peak compared to the baseline value, which is sensitive to the change in the amplitude and latency simultaneously. We used the slope-measure for EP and single trials and compared the significant change detection time with that of the conventional peak-to-peak method. When applied to single trials, each single trial signal was processed with optimal filters before using the slope-measure. In this retrospective data analysis, 7 patients who underwent cerebral aneurysm clipping surgery for unruptured aneurysm middle cerebral artery (MCA) bifurcation were included. Results We found that this simple slope-measure has a detection time that is as early or earlier than that of the conventional method; furthermore, using the slope-measure in optimally filtered single trials provides warning signs earlier than that of the conventional method during MCA clipping surgery. Conclusion Our results have confirmed the feasibility of the slope-measure for intraoperative SEP monitoring. This is a novel study that provides a useful measure for either EP or single trials in intraoperative SEP monitoring.

Jin, Seung-Hyun; Kim, Jeong Eun; Choi, Young Doo

2014-01-01

111

Intraoperative changes in transcranial motor evoked potentials and somatosensory evoked potentials predicting outcome in children with intramedullary spinal cord tumors  

PubMed Central

Object Intraoperative dorsal column mapping, transcranial motor evoked potentials (TcMEPs), and somatosensory evoked potentials (SSEPs) have been used in adults to assist with the resection of intramedullary spinal cord tumors (IMSCTs) and to predict postoperative motor deficits. The authors sought to determine whether changes in MEP and SSEP waveforms would similarly predict postoperative motor deficits in children. Methods The authors reviewed charts and intraoperative records for children who had undergone resection for IMSCTs as well as dorsal column mapping and TcMEP and SSEP monitoring. Motor evoked potential data were supplemented with electromyography data obtained using a Kartush microstimulator (Medtronic Inc.). Motor strength was graded using the Medical Research Council (MRC) scale during the preoperative, immediate postoperative, and follow-up periods. Reductions in SSEPs were documented after mechanical traction, in response to maneuvers with the cavitational ultrasonic surgical aspirator (CUSA), or both. Results Data from 12 patients were analyzed. Three lesions were encountered in the cervical and 7 in the thoracic spinal cord. Two patients had lesions of the cervicomedullary junction and upper spinal cord. Intraoperative MEP changes were noted in half of the patients. In these cases, normal polyphasic signals converted to biphasic signals, and these changes correlated with a loss of 1–2 grades in motor strength. One patient lost MEP signals completely and recovered strength to MRC Grade 4/5. The 2 patients with high cervical lesions showed neither intraoperative MEP changes nor motor deficits postoperatively. Dorsal columns were mapped in 7 patients, and the midline was determined accurately in all 7. Somatosensory evoked potentials were decreased in 7 patients. Two patients each had 2 SSEP decreases in response to traction intraoperatively but had no new sensory findings postoperatively. Another 2 patients had 3 traction-related SSEP decreases intraoperatively, and both had new postoperative sensory deficits that resolved. One additional patient had a CUSA-related SSEP decrease intraoperatively, which resolved postoperatively, and the last patient had 3 traction-related sensory deficits and a CUSA-related sensory deficit postoperatively, none of which resolved. Conclusions Intraoperative TcMEPs and SSEPs can predict the degree of postoperative motor deficit in pediatric patients undergoing IMSCT resection. This technique, combined with dorsal column mapping, is particularly useful in resecting lesions of the upper cervical cord, which are generally considered to be high risk in this population. Furthermore, the spinal cord appears to be less tolerant of repeated intraoperative SSEP decreases, with 3 successive insults most likely to yield postoperative sensory deficits. Changes in TcMEPs and SSEP waveforms can signal the need to guard against excessive manipulation thereby increasing the safety of tumor resection. PMID:24702615

Cheng, Jason S.; Ivan, Michael E.; Stapleton, Christopher J.; Quinones-HinoJosa, AlfreDo; Gupta, Nalin; Auguste, Kurtis I.

2015-01-01

112

[The role of brain stem evoked potentials in acoustic neuroma screening and diagnosis].  

PubMed

For acoustic tumours > 2 cm the sensitivity of brainstem evoked auditory potentials (BAEP) to detect the retrocochlear lesions is 100 % as for magnetic resonance imaging (MRI). According to the literature the sensitivity for detection of retrocochlear pathology in tumours < 1 cm is estimated to be between 75 % and 95 %. In the MRI the sensitivity and specificity in such smaller tumours is reported to be 100 %. A normal result of the BAEP examination and for additional neurootologic tests helps to increase the rate of safe exclusion of retrocochlear pathology. By at this time not yet routinely available modifications of the BAEP examination and by additional neurootologic tests the sensitivity of the electrophysiological screening procedure can be brought up to nearly 100 %. Thereby their important role as the primary screening procedure can be re-established. Besides a possible detection of a retrocochlear lesion the BAEP together with the additional neurootologic test provide important information on the functional status of the hearing and equilibrium system. Possible safe indications for inclusion and for exclusion criteria of an MRI screening for individual patients will be provided and discussed. PMID:18654941

Maurer, J

2008-08-01

113

Assessment of visual and auditory evoked potentials in multiple sclerosis patients with and without fatigue.  

PubMed

The aim of the study was to evaluate visual and brainstem auditory evoked potentials (VEP, BAEP) in multiple sclerosis (MS) patients with regards to fatigue and disease-related variables. The study comprised 86 MS patients and 40 controls. Fatigue was assessed using the Fatigue Severity Scale (FSS/FSS-5) and the Modified Fatigue Impact Scale (MFIS). Latencies and amplitudes of the P100 component of VEP and the I-V components of BAEP were analyzed. The results of EP were compared between non-fatigued, moderately and severely fatigued MS patients and controls. P100 latency was increased and amplitude decreased in moderately and severely fatigued MS subjects. The latency of the V component of BAEP and interlatencies I-III-V were increased in severely fatigued patients. The amplitude of the V component was lowered in fatigued patients. VEP and BAEP abnormalities were usually one-sided. Interocular P100 latency difference tended to correlate with FSS/FSS-5. The parameters of VEP and BAEP correlated with functional system scores but not with MS duration, overall degree of disability or its progression over time. Significant, usually asymmetrical VEP and BAEP abnormalities were found in fatigued MS patients, with no relationships to disease-related variables. EP may be considered an electrophysiological marker of fatigue in MS patients. PMID:25240278

Pokryszko-Dragan, Anna; Bilinska, Malgorzata; Gruszka, Ewa; Kusinska, El?bieta; Podemski, Ryszard

2015-02-01

114

Detection of temporal gaps in noise in dolphins: evoked-potential study.  

PubMed

Temporal resolution of hearing was studied in bottlenosed dolphins by recording the auditory brain-stem response (ABR) evoked by gap in noise. Gaps shorter than 0.5 ms evoked a response combining both off- and on-components; longer gaps evoked separate off- and on-responses. Both the response to a short gap and on-response to the end of a long gap increased with increasing gap duration. On-response recovered completely at gap duration of 5-10 ms. Small but detectable response arose at gap duration as short as 0.1 ms. Contrary to the on-response after a long silence, the response to a short gap was less dependent on noise intensity. From these data, the temporal transfer function of the supposed integrator was derived assuming nonlinear transform of the integrator output to ABR amplitude. Equivalent rectangular duration of the found temporal transfer function was 0.27 ms. PMID:9265761

Popov, V V; Supin AYa

1997-08-01

115

Automatic denoising of single-trial evoked potentials.  

PubMed

We present an automatic denoising method based on the wavelet transform to obtain single trial evoked potentials. The method is based on the inter- and intra-scale variability of the wavelet coefficients and their deviations from baseline values. The performance of the method is tested with simulated event related potentials (ERPs) and with real visual and auditory ERPs. For the simulated data the presented method gives a significant improvement in the observation of single trial ERPs as well as in the estimation of their amplitudes and latencies, in comparison with a standard denoising technique (Donoho's thresholding) and in comparison with the noisy single trials. For the real data, the proposed method largely filters the spontaneous EEG activity, thus helping the identification of single trial visual and auditory ERPs. The proposed method provides a simple, automatic and fast tool that allows the study of single trial responses and their correlations with behavior. PMID:23142653

Ahmadi, Maryam; Quian Quiroga, Rodrigo

2013-02-01

116

Somatosensory evoked potentials during standing posture on different support surface.  

PubMed

Somatosensory evoked potentials in response to stimulation of the posterior tibial nerve at the ankle were recorded during standing on stable ground or on unstable support surface (seesaw) or on support surface short in relation to foot length. During standing on the seesaw and on the short support surface a decrease in the amplitude of the early component (N32-P39) was observed. The amplitude of N49-P58 decreased during standing on the short support surface. The amplitude of the later components (N49-P58; P58-N76; N76-P117) decreased during standing on the seesaw in comparison to that during standing on the stable ground and on the short support surface. Thus, the attenuation of the cerebral potential during standing depend on the conditions for maintenance of posture. PMID:1817690

Gavrilenko, T; Gatev, P; Gantchev, G N; Popivanov, D

1991-01-01

117

Recording Visual Evoked Potentials and Auditory Evoked P300 at 9.4T Static Magnetic Field  

PubMed Central

Simultaneous recording of electroencephalography (EEG) and functional magnetic resonance imaging (fMRI) has shown a number of advantages that make this multimodal technique superior to fMRI alone. The feasibility of recording EEG at ultra-high static magnetic field up to 9.4T was recently demonstrated and promises to be implemented soon in fMRI studies at ultra high magnetic fields. Recording visual evoked potentials are expected to be amongst the most simple for simultaneous EEG/fMRI at ultra-high magnetic field due to the easy assessment of the visual cortex. Auditory evoked P300 measurements are of interest since it is believed that they represent the earliest stage of cognitive processing. In this study, we investigate the feasibility of recording visual evoked potentials and auditory evoked P300 in a 9.4T static magnetic field. For this purpose, EEG data were recorded from 26 healthy volunteers inside a 9.4T MR scanner using a 32-channel MR compatible EEG system. Visual stimulation and auditory oddball paradigm were presented in order to elicit evoked related potentials (ERP). Recordings made outside the scanner were performed using the same stimuli and EEG system for comparison purposes. We were able to retrieve visual P100 and auditory P300 evoked potentials at 9.4T static magnetic field after correction of the ballistocardiogram artefact using independent component analysis. The latencies of the ERPs recorded at 9.4T were not different from those recorded at 0T. The amplitudes of ERPs were higher at 9.4T when compared to recordings at 0T. Nevertheless, it seems that the increased amplitudes of the ERPs are due to the effect of the ultra-high field on the EEG recording system rather than alteration in the intrinsic processes that generate the electrophysiological responses. PMID:23650538

Hahn, David; Boers, Frank; Shah, N. Jon

2013-01-01

118

Recording visual evoked potentials and auditory evoked P300 at 9.4T static magnetic field.  

PubMed

Simultaneous recording of electroencephalography (EEG) and functional magnetic resonance imaging (fMRI) has shown a number of advantages that make this multimodal technique superior to fMRI alone. The feasibility of recording EEG at ultra-high static magnetic field up to 9.4 T was recently demonstrated and promises to be implemented soon in fMRI studies at ultra high magnetic fields. Recording visual evoked potentials are expected to be amongst the most simple for simultaneous EEG/fMRI at ultra-high magnetic field due to the easy assessment of the visual cortex. Auditory evoked P300 measurements are of interest since it is believed that they represent the earliest stage of cognitive processing. In this study, we investigate the feasibility of recording visual evoked potentials and auditory evoked P300 in a 9.4 T static magnetic field. For this purpose, EEG data were recorded from 26 healthy volunteers inside a 9.4 T MR scanner using a 32-channel MR compatible EEG system. Visual stimulation and auditory oddball paradigm were presented in order to elicit evoked related potentials (ERP). Recordings made outside the scanner were performed using the same stimuli and EEG system for comparison purposes. We were able to retrieve visual P100 and auditory P300 evoked potentials at 9.4 T static magnetic field after correction of the ballistocardiogram artefact using independent component analysis. The latencies of the ERPs recorded at 9.4 T were not different from those recorded at 0 T. The amplitudes of ERPs were higher at 9.4 T when compared to recordings at 0 T. Nevertheless, it seems that the increased amplitudes of the ERPs are due to the effect of the ultra-high field on the EEG recording system rather than alteration in the intrinsic processes that generate the electrophysiological responses. PMID:23650538

Arrubla, Jorge; Neuner, Irene; Hahn, David; Boers, Frank; Shah, N Jon

2013-01-01

119

[Effect of dehydrobenzperidol (DHB) on cortical and thalamic somatosensory evoked potentials in patients with muscle dystonia].  

PubMed

Investigations of somatosensory evoked potentials in patients with muscular dystonia meet with difficulties due to abnormal muscle tone and dyskinesia producing myogenic artifacts deforming potentials recorded after their evoking. For obtaining better conditions for recording of somatosensory evoked potentials single dose of DHB was used. Somatosensory evoked potentials were recorded before and after operations and during stereotactic thalamotomy of the complex of the VL nucleus in the thalamus. The authors report the results of investigations in the above mentioned three periods of treatment in hospital. The results suggest the hypothesis that DHB affects the cerebellofugal transmission organizing the proper muscle tone. PMID:3268737

Mempel, E; Tarnecki, R; Ligezi?ska, B; Paw?owski, G

1988-01-01

120

Visual evoked potentials and selective attention to points in space  

NASA Technical Reports Server (NTRS)

Visual evoked potentials (VEPs) were recorded to sequences of flashes delivered to the right and left visual fields while subjects responded promptly to designated stimuli in one field at a time (focused attention), in both fields at once (divided attention), or to neither field (passive). Three stimulus schedules were used: the first was a replication of a previous study (Eason, Harter, and White, 1969) where left- and right-field flashes were delivered quasi-independently, while in the other two the flashes were delivered to the two fields in random order (Bernoulli sequence). VEPs to attended-field stimuli were enhanced at both occipital (O2) and central (Cz) recording sites under all stimulus sequences, but different components were affected at the two scalp sites. It was suggested that the VEP at O2 may reflect modality-specific processing events, while the response at Cz, like its auditory homologue, may index more general aspects of selective attention.

Van Voorhis, S.; Hillyard, S. A.

1977-01-01

121

Conscious Wireless Electroretinogram and Visual Evoked Potentials in Rats  

PubMed Central

The electroretinogram (ERG, retina) and visual evoked potential (VEP, brain) are widely used in vivo tools assaying the integrity of the visual pathway. Current recordings in preclinical models are conducted under anesthesia, which alters neural physiology and contaminates responses. We describe a conscious wireless ERG and VEP recording platform in rats. Using a novel surgical technique to chronically implant electrodes subconjunctivally on the eye and epidurally over the visual cortex, we are able to record stable and repeatable conscious ERG and VEP signals over at least 1 month. We show that the use of anaesthetics, necessary for conventional ERG and VEP measurements, alters electrophysiology recordings. Conscious visual electrophysiology improves the viability of longitudinal studies by eliminating complications associated with repeated anaesthesia. It will also enable uncontaminated assessment of drug effects, allowing the eye to be used as an effective biomarker of the central nervous system. PMID:24069276

He, Zheng; Dang, Trung M.; Vingrys, Algis J.; Fish, Rebecca L.; Gurrell, Rachel; Brain, Phil; Bui, Bang V.

2013-01-01

122

Polar bear Ursus maritimus hearing measured with auditory evoked potentials.  

PubMed

While there has been recent concern about the effects of sound on marine mammals, including polar bears, there are no data available measuring the hearing of any bear. The in-air hearing of three polar bears was measured using evoked auditory potentials obtained while tone pips were played to three individually anaesthetized bears at the Kolmården Djurpark. Hearing was tested in half-octave steps from 1 to 22.5 kHz. Measurements were not obtainable at 1 kHz and best sensitivity was found in the range from 11.2-22.5 kHz. Considering the tone pips were short and background noise measurements were available, absolute measurements were estimated based on an assumed mammalian integration time of 300 ms. These data show sensitive hearing in the polar bear over a wide frequency range and should cause those concerned with the introduction of anthropogenic noise into the polar bear's environment to operate with caution. PMID:17371910

Nachtigall, Paul E; Supin, Alexander Y; Amundin, Mats; Röken, Bengt; Møller, Thorsten; Mooney, T Aran; Taylor, Kristen A; Yuen, Michelle

2007-04-01

123

Multi-Channel Noise Reduced Visual Evoked Potential Analysis  

NASA Astrophysics Data System (ADS)

In this paper, Principal Component Analysis (PCA) is used to reduce noise from multi-channel Visual Evoked Potential (VEP) signals. PCA is applied to reduce noise from multi-channel VEP signals because VEP signals are more correlated from one channel to another as compared to noise during visual perception. Emulated VEP signals contaminated with noise are used to show the noise reduction ability of PCA. These noise reduced VEP signals are analysed in the gamma spectral band to classify alcoholics and non-alcoholics with a Fuzzy ARTMAP (FA) neural network. A zero phase Butterworth digital filter is used to extract gamma band power in spectral range of 30 to 50 Hz from these noise reduced VEP signals. The results using 800 VEP signals give an average FA classification of 92.50 % with the application of PCA and 83.33 % without the application of PCA.

Palaniappan, Ramaswamy; Raveendran, Paramesran; Nishida, Shogo

124

Vestibular Evoked Myogenic Potentials in Normal Mice and Phex Mice With Spontaneous Endolymphatic Hydrops  

PubMed Central

Objective and Background Vestibular evoked myogenic potentials (VEMPs) have been recorded from the neck musculature and the cervical spinal cord in humans and a limited number of laboratory animals in response to loud sound. However, the mouse VEMP has yet to be described. Evaluation of the sacculocollic pathway via VEMPs in mice can set the stage for future evaluations of mutant mice that now play an important role in research regarding human auditory and vestibular dysfunction. Materials and Methods Sound-evoked potentials were recorded from the neck extensor muscles and the cervical spinal cord in normal adult mice and in circling PhexHyp-Duk/y mice with known vestibular abnormalities, including endolymphatic hydrops (ELH). Results Biphasic potentials were recorded from all normal animals. The mean threshold of the VEMP response in normal adult mice was 60 dB normal hearing level with a mean peak latency of 6.25 ± 0.46 and 7.95 ± 0.42 milliseconds for p1 and n1 peaks, respectively. At the maximum sound intensity used (100 dB normal hearing level), 4 of 5 Phex mice did not exhibit VEMP responses, and 1 showed an elevated threshold, but normal response, with regard to peak latency and amplitude. The histologic findings in all of these Phex mice were consistent with distended membranous labyrinth, displaced Reissner membrane, ganglion cell loss, and ELH. Conclusion This is the first report of VEMP recordings in mice and the first report of abnormal VEMPs in a mouse model with ELH. The characteristics of these potentials such as higher response threshold in comparison to auditory brainstem response, myogenic nature of the response, and latency correlation with the cervical recording (accessory nerve nucleus) were similar to those of VEMPs in humans, guinea pigs, cats, and rats, suggesting that the mouse may be used as an animal model in the study of VEMPs. The simplicity and reliability of these recordings make the VEMP a uniquely informative test for assessing vestibular function, and these results suggest that they may be informative in mice with various mutations. However, further investigation is necessary. PMID:19300299

Sheykholeslami, Kianoush; Megerian, Cliff A.; Zheng, Qing Y.

2010-01-01

125

Stimulus dependencies of the gerbil brain-stem auditory-evoked response (BAER). III: Additivity of click level and rate with noise level.  

PubMed

Two experiments were performed that evaluated the effects of ipsilateral-direct broadband noise maskers on the gerbil brain-stem auditory-evoked response (BAER) to click stimuli. In experiment 1, clicks were presented at 27 Hz at levels including 70, 80, 90, and 100 dB pSPL. Noise conditions included a no-noise control, and included noise levels varying in 10-dB increments from 20 dB SPL to a maximum noise level of 50, 60, 70, and 80 dB SPL for click levels of 70, 80, 90, and 100 dB pSPL, respectively. Gerbil BAER peaks were labeled with small roman numerals to distinguish them from human BAER peaks. The dependent variables included waves i and v latencies and amplitudes. Peak latencies increased and peak amplitudes decreased with decreasing click level and increasing noise level. To a first approximation, peak latencies and amplitudes showed changes with increasing noise level that were similar across click level. With increasing click level, there was little or no effect on the i-v interval. There was an increase in the i-v interval with increasing noise level. In experiment 2, click level was held constant at 90 dB pSPL, and click rates included 15, 40, 65, and 90 Hz. For each click rate, noise conditions included a no-noise control, and noise levels included 20, 30, 40, 50, 60, and 70 dB SPL. With increasing click rate and noise level, there was an increase in peak latencies, an increase in the i-v interval, and a decrease in peak amplitudes. The magnitude of peak latency and amplitude shifts with increasing click rate was dependent on noise level. Specifically, the magnitude of rate-dependent changes decreased with increasing level of broadband noise. These data are compared to human BAER experiments, and are found to be in fundamental agreement. PMID:2269738

Burkard, R; Voigt, H F

1990-11-01

126

The effects of anesthesia with increasing end-expiratory concentrations of sevoflurane on midlatency auditory evoked potentials.  

PubMed

We studied midlatency auditory evoked potentials (MLAEP) during general anesthesia with increasing end-expiratory concentrations of sevoflurane in 12 patients scheduled for elective gynecologic surgery. After oral premedication with 20 mg clorazepate dipotassium, anesthesia was induced with etomidate (0.2 mg/kg intravenously [IV]). Vecuronium (0.1 mg/kg) was given for neuromuscular block, and controlled ventilation with sevoflurane in 100% O2 was instituted. Auditory evoked potentials were recorded in the awake state and during anesthesia with end-expiratory steady-state concentrations of 0.5, 1.0, 1.5, and 2.0 vol% of sevoflurane on vertex (positive) and mastoids on both sides (negative). Latencies of peaks V, Na, Pa, Nb, and P1 (ms) and amplitudes of Na/Pa, Pa/Nb, and Nb/P1 (microV) were measured. In the awake state, MLAEP had high peak-to-peak amplitudes and a periodic waveform. During general anesthesia with increasing end-expiratory concentrations of sevoflurane, the latency of the brainstem response V increased slightly. In contrast, MLAEP showed marked dose-dependent, statistically significant increases in the latencies of Na, Pa, Nb, and P1 and decreases in the amplitudes of Na/Pa, Pa/Nb, and Nb/P1. Under 2 vol% of sevoflurane, MLAEPs were severely attenuated or abolished. Based on these observations, > or = 1.5 vol% sevoflurane should suppress phenomena such as auditory perceptions, intraoperative wakefulness, and awareness. PMID:7574016

Schwender, D; Conzen, P; Klasing, S; Finsterer, U; Pöppel, E; Peter, K

1995-10-01

127

[Loss of brain stem auditory evoked potential waves I and II during controlled hypotension].  

PubMed

For surgical removal of a malignant choroid melanoma, it is necessary to reduce systolic blood pressure to around 50-60 mmHg in order to prevent choroidal haemorrhages. However, blood pressure reduction is associated with the risk of cerebral ischaemia. We report a patient with a malignant choroid melanoma in whom waves I and II of the brainstem auditory evoked potentials (BAEP) disappeared during surgery under controlled arterial hypotension and hypothermia (31.1 degrees C). The waves could be recorded again immediately after the mean arterial pressure was increased from 48 to 77 mmHg. The oesophageal temperature had dropped by 0.3 degrees C at this time. The 2-channel electroencephalogram (EEG) showed no irregularities during this time period. A bilateral, reversible, apparently blood-pressure-dependent loss of waves I and II during arterial hypotension despite a normal EEG has to our knowledge not been previously described in the literature. The isolated loss of waves I and II with maintenance of waves III, IV, and V is unusual. The literature contains reports of acoustic neurinoma patients in whom only wave V could be recorded. This is regarded as an indication of continued impulse conduction despite the loss of waves I to IV. Others have observed a patient with temporary and reversible loss of BAEP wave I due to vasospasm of the internal auditory artery that apparently occurred during or shortly after manipulation of the internal auditory meatus. Assuming anatomic peculiarities in the blood supply to the generators of the BAEP waves, a stenosis of the basilar artery could be considered as the cause of the bilateral reversible loss of waves I and II. Another potential source could be induced hypothermia, but this does not seem very likely because the patient's temperature was 0.3 degrees C lower at the return of the waves than at their loss. PMID:8678270

Papadopoulos, G; Lang, M; Link, J; Schäfer, M; Schaffartzik, W; Eyrich, K; Bornfeld, N; Foerster, M H

1995-11-01

128

The relationship between latency of auditory evoked potentials, simple reaction time, and stimulus intensity  

Microsoft Academic Search

The effects of loudness on the latency of evoked potentials and on simple reaction time were compared. It was found that both reaction time and the evoked-potential latency increases with decreasing stimulus intensity. However, different slopes of the curves were found. This is explained in terms of the arousal effect of loud auditory stimuli.

Piotr Jaskownki; Krzysztof Rybarczyk; Feliks Jaroszyk

1994-01-01

129

Extracting Single Trial Visual Evoked Potentials Using Iterative Generalized Eigen Value Decomposition  

Microsoft Academic Search

The activity generated in the brain in response to external stimulations which is named the evoked potential (EP) is typically buried in the background EEG. Because of the low signal to noise ratio of EPs, it is difficult to record single trial evoked potentials. The traditional technique which is based on ensemble averaging destroys the dynamic information of single trials.

S. Hajipour; M. B. Shamsollahi; H. Mamaghanian; V. Abootalebi

2008-01-01

130

ACUTE SULFOLANE EXPOSURE PRODUCES TEMPERATURE-INDEPENDENT AND DEPENDENT CHANGES IN VISUAL EVOKED POTENTIALS  

EPA Science Inventory

The report describes the consequences of acute exposure to sulfolane upon the visual system, as measured using flash evoked potential (FEPs) and pattern reversal evoked potentials (PREPs). A single injection of either 1/2 or 1/4, but not 1/8 the i.p. LD50 (1600 mg/kg) produced si...

131

MEASUREMENT OF THE ELECTRICALLY EVOKED COMPOUND ACTION POTENTIAL VIA A NEURAL RESPONSE TELEMETRY SYSTEM  

Microsoft Academic Search

The main aim of this study was to validate a new technique, neural response telemetry (NRT), for measuring the electrically evoked compound action potential in adult cochlear implant users via their Nucleus CI24M implant. Thirty-eight adults were evaluated with a variety of measurement procedures with the NRT software. Electrically evoked compound action potentials were obtained in 31 of the 38

JOACHIM MÜLLER-DEILE; MATTHIAS STECKER; RNST VON WALLENBERG

132

Intraoperative somatosensory evoked potential monitoring of the sciatic nerve: an animal model.  

PubMed

Sciatic, peroneal, and tibial nerves were isolated in 18 hind limbs in 10 adult mongrel cats. A pair of needle electrodes was used to stimulate both divisions of the sciatic nerve individually at the level of the popliteal fossa. The sciatic nerve was injured by complete or partial transection, crush, and controlled compression. Motor function was correlated with intraoperative cortical somatosensory evoked potential and spinal somatosensory evoked potential tracings. We observed that significant changes in the waveforms of cortical somatosensory evoked potential and spinal somatosensory evoked potential tracings immediately precede postoperative peripheral nerve deficits, and that loss of motor function may be avoided by immediate response to significant spinal somatosensory evoked potential and cortical somatosensory evoked potential waveform changes. A complete motor palsy can be created in one division of the sciatic nerve while normal tracings are being obtained in the other division of the nerve. Stimulating both divisions may result in a spinal somatosensory-evoked potential/cortical somatosensory evoked potential tracing that masks the deficit that is present in only one nerve division. PMID:1556625

Moed, B R; Maxey, J W; Minster, G J

1992-01-01

133

Memory impairment and auditory evoked potential gating deficit in schizophrenia.  

PubMed

Impaired sensory gating and memory function were reported in a study of 10 schizophrenic patients and 10 age- and sex-matched normal subjects. The P50 component of the auditory evoked potential was used as an index of gating. Explicit memory was tested with the Wechsler Memory Scale and implicit memory by artificial grammar learning. The schizophrenic patients showed deficits in both verbal paired associate and visual reproduction tasks. They demonstrated impaired implicit learning in color patterns but not letter strings. They also showed impaired P50 sensory gating. Three-dimensional brain mapping revealed a differential distribution of brain potentials in the processing of S1 and S2 at either P50 or N100 in both groups. However, the group difference was not statistically confirmed. In the controls, both implicit letter-string learning and explicit verbal paired associates were positively correlated with N100 gating, suggesting an association of the early attentive component with lexicons. In the schizophrenic patients, color-pattern implicit learning was positively correlated with P50 gating. The modality-specific impairment of implicit learning in schizophrenia may reflect a failure of adaptive filtering on the flooding input from color patterns. PMID:15033186

Hsieh, Ming H; Liu, Kristina; Liu, Shi-Kai; Chiu, Ming-Jang; Hwu, Hai-Gwo; Chen, Andrew C N

2004-02-15

134

Visual evoked potentials in children prenatally exposed to methylmercury.  

PubMed

Prenatal exposure to methylmercury can cause both neurobehavioral deficits and neurophysiological changes. However, evidence of neurotoxic effects within the visual nervous system is inconsistent, possibly due to incomplete statistical adjustment for beneficial nutritional factors. We evaluated the effect of prenatal methylmercury exposure on visual evoked potential (VEP) latencies in Faroese children with elevated prenatal methylmercury exposure. A cohort of 182 singleton term births was assembled in the Faroe Islands during 1994-1995. At age 7 years, VEP tracings were obtained from 139 cohort subjects after exclusion of subjects with abnormal vision conditions. We used multiple regression analysis to evaluate the association of mercury concentrations in cord blood and maternal hair at parturition with VEP latencies after adjustment for potential confounders that included the cord-serum phospholipid concentration of n-3 polyunsaturated fatty acids (PUFAs) and the duration of breastfeeding. Unadjusted correlations between mercury exposure and VEP latencies were equivocal. Multiple regression models showed that increased mercury concentrations, especially in maternal hair, were associated with delayed latencies for VEP peak N145. After covariate adjustment, a delay of 2.22 ms (p=0.02) was seen for each doubling of the mercury concentration in maternal hair. In agreement with neuropsychological findings, the present study suggests that prenatal methylmercury exposure may have an adverse effect on VEP findings despite the absence of clinical toxicity to the visual system. However, this association was apparent only after adjustment for n-3 PUFA status. PMID:23548974

Yorifuji, Takashi; Murata, Katsuyuki; Bjerve, Kristian S; Choi, Anna L; Weihe, Pal; Grandjean, Philippe

2013-07-01

135

[Cerebral evoked potentials in comatose states of various etiology].  

PubMed

The authors studied the evoked potentials (EPs) of the brain cortex in patients in comatose states of various etiology as well as the EPs of the brain cortical and subcortical structures of the animals during simulation of the conditions studied in clinical practice. A sharp drop in the amplitude of early waves and an increase in the amplitude and latency of late EP waves in all the cerebral structures irrespective of the coma genesis were disclosed. The changes were of a simultaneous and generalized character with a greater similarity between the EPs of the cortical zones but an increase of their difference from the subcortical structures. These facts are explained by the deprivation of the nonspecific systems of both cortical and local inhibitory influence which leads to the late activation of the brain specific systems. It is assumed that the space-time dissociation in the action of various cerebral systems is, regardless of the coma genesis, one of the principal mechanisms giving rise to disorders of information perception, analysis and processing. PMID:6666451

Akimov, G A; Nasonkin, O S; Semin, G F; Pashkovski?, E V

1983-01-01

136

Long-latency evoked potentials to irrelevant, deviant stimuli  

NASA Technical Reports Server (NTRS)

Occasional shifts of loudness in a repetitive train of clicks elicited a late-positive wave (P3a) in nonattending subjects which peaked at a mean latency of 258 msec and had a frontocentral scalp distribution; P3a was typically preceded by an 'N2' component at 196 msec. The P3a wave was distinguishable from the longer-latency (378 msec) parietocentrally distributed 'P3b' wave that was evoked by the same stimulus in an actively attending subject, thus confirming the findings of Squires et al. (1975). Infrequently presented single sounds did not produce large or consistent N2-P3a components; the critical condition for the generation of an N2-P3a wave seemed to be that the infrequent sounds represent a deviation (intensity increment or decrement) from a repetitive background. Furthermore, increasing the repetition rate of the background clicks drastically reduced N1-P2 amplitude but had little effect on the amplitude of N2-P3a. This suggests that N2-P3a is not simply a delayed N1-P2 'vertex potential', but rather reflects the operation of a 'mismatch' detector, which registers deviations from an ongoing auditory background.

Snyder, E.; Hillyard, S. A.

1976-01-01

137

Vestibular evoked myogenic potentials (VEMPs): usefulness in clinical neurotology.  

PubMed

Testing vestibular evoked myogenic potentials (VEMPs) may be the most important new clinical test for evaluation of vestibular function developed during the past 100 years since the introduction of the caloric test. VEMPs are easily recordable and therefore suitable for everyday testing in clinical neurotology. VEMPs in response to air-conducted sound stimulation using surface electrodes over the sternocleidomastoid muscles reveal saccular function, inferior vestibular nerve function, and vestibulocollic connections. At present, VEMPs are of clinical importance for estimating the severity of peripheral vestibular damage due to different pathophysiologic processes such as Ménière's disease, vestibular neuritis, and vestibular schwannoma. VEMPs can also be used to document vestibular hypersensitivity to sounds (Tullio phenomenon). In addition, VEMP testing constitutes an electrophysiologic method that is able to detect subclinical lesions in central vestibular pathways in patients with multiple sclerosis. In the near future, testing ocular VEMPs (OVEMPs) in response to bone-conducted vibration may prove to be of clinical importance for the evaluation of utricular function. PMID:19834866

Brantberg, Krister

2009-11-01

138

Vestibular evoked myogenic potentials in patients with BPPV  

PubMed Central

Summary Background The probable cause of Benign Paroxysmal Positional Vertigo (BPPV) is a degeneration of the oto lithic organs (utricle and saccule). The aim of the study is to find possible alterations in Vestibular Evoked Myogenic Potentials (VEMP) recordings in BPPV patients, because the saccule is part of the VEMP pathway. Material/Methods 27 BPPV patients (24 unilateral and 3 bilateral) aged 20 to 70 years and 30 healthy age matched controls. BPPV was diagnosed by the upbeating geotropic nystagmus found in the supine position with the head overextended towards one side. The subjects were investigated with pure tone audiometry, bi-thermal caloric test with electronystagmographic (ENG) recording, and VEMP recording. Results P1 latency and N1 latency did not present any statistical difference between control ears and affected ears of the BPPV population. The percentage of abnormal VEMP in the BPPV population was statistically higher than in the control ears (p<0.005). No significant relationship could be shown between the occurrence of Canal Paresis and abnormal VEMP. No relationship was found between the side (right or left ear) where BPPV appeared clinically and the side where abnormal VEMP was registered. Conclusions BPPV is a clinical entity associated with increased occurrence of abnormal VEMP recordings, possibly due to degeneration of the saccular macula, which is part of the neural VEMP pathway. PMID:21169909

Korres, Stavros; Gkoritsa, Eleni; Giannakakou-Razelou, Dimitra; Yiotakis, Ioannis; Riga, Maria; Nikolpoulos, Thomas P.

2011-01-01

139

Time-varying adaptive filters for evoked potential estimation.  

PubMed

Adaptive implementation of an optimal time-varying filter (TVF) for evoked potential (EP) estimation is addressed in this paper. A data-adaptive scheme is used, which converges asymptotically to the optimal TVF solution. Two basic adaptive TVF's (ATVF's) are first introduced, namely least mean square (LMS) ATVF and recursive least-squares (RLS) ATVF. The latter converges much faster than the former. Since the basic ATVF's usually require a relatively large set of response trials to get a meaningful solution, a reduced-order ATVF is further presented and the corresponding LMS and RLS (including a fast RLS) adaptive algorithms are developed. To save memory, a truncated Fourier expansion is suggested to express approximately the time-sequenced weight-vectors of the ATVF's, resulting in a simplified reduced-order ATVF. Finally, extensive simulations are provided to confirm the superior performance of the ATVF's. The present ATVF's can be used as prefilters for latency-corrected average (LCA) processing to obtain more informative estimates of EP signals. PMID:8001995

Yu, X H; He, Z Y; Zhang, Y S

1994-11-01

140

Measuring action potential-evoked transmission at individual synaptic contacts  

PubMed Central

In the neuronal culture experimental system, the total synaptic connection between two neurons can consist of large numbers of synaptic sites, each behaving probabilistically. Studies of synaptic function with paired recordings typically consider the summed response across all of these sites and from this infer the average response. Understanding of synaptic transmission and plasticity could be improved by examination of activity at as few synaptic sites as possible. To this end, we develop a system for recording responses from individual contacts. It relies on a precisely regulated pneumatic/hydrostatic pressure system to create a microenvironment within which individual synapses are active, and an acoustic signature method to monitor the stability of this microenvironment noninvasively. With this method we are able to record action potential-evoked postsynaptic currents consistent with individual quanta. The approach does not distort synaptic current waveforms and permits stable recording for several hours. The method is applied to address mechanisms of short-term plasticity, the variability of latency at individual synaptic sites and, in a preliminary experiment, the independence of nearby synapses on the same axon. PMID:22626987

Nauen, David W; Bi, Guo-Qiang

2014-01-01

141

Pattern Visual Evoked Potentials Elicited by Organic Electroluminescence Screen  

PubMed Central

Purpose. To determine whether organic electroluminescence (OLED) screens can be used as visual stimulators to elicit pattern-reversal visual evoked potentials (p-VEPs). Method. Checkerboard patterns were generated on a conventional cathode-ray tube (S710, Compaq Computer Co., USA) screen and on an OLED (17 inches, 320 × 230?mm, PVM-1741, Sony, Tokyo, Japan) screen. The time course of the luminance changes of each monitor was measured with a photodiode. The p-VEPs elicited by these two screens were recorded from 15 eyes of 9 healthy volunteers (22.0 ± 0.8 years). Results. The OLED screen had a constant time delay from the onset of the trigger signal to the start of the luminescence change. The delay during the reversal phase from black to white for the pattern was 1.0?msec on the cathode-ray tube (CRT) screen and 0.5?msec on the OLED screen. No significant differences in the amplitudes of P100 and the implicit times of N75 and P100 were observed in the p-VEPs elicited by the CRT and the OLED screens. Conclusion. The OLED screen can be used as a visual stimulator to elicit p-VEPs; however the time delay and the specific properties in the luminance change must be taken into account. PMID:25197652

Matsumoto, Celso Soiti; Shinoda, Kei; Matsumoto, Harue; Funada, Hideaki; Minoda, Haruka

2014-01-01

142

High stimulus rate brainstem auditory evoked potential in benign paroxysmal positional vertigo.  

PubMed

The objective of this study is to use high (49/s) and low (9/s) stimulation rates of the BAEP to investigate the possible mechanism responsible for BPPV. A total of 81 patients (55 women and 26 men, mean age ± SD = 54.6 ± 15.0) with idiopathic BPPV, as well as 106 control subjects (70 women and 36 men, mean age ± SD = 51.2 ± 16.3) participated in the study. The results of high (49/s) and low (9/s) stimulation rates of the BAEP test were compared and analyzed. The difference in BAEP wave I peak latencies between low and high stimulation rate (DPL I) and BAEP wave I peak latency in high stimulation (HPL I) of affected ears (0.24 ± 0.14 and 1.91 ± 0.21 ms) in BPPV patients were significantly prolonged when compared with the controls (0.10 ± 0.08 and 1.76 ± 0.18 ms) and unaffected ears (0.12 ± 0.10 and 1.82 ± 0.21 ms) (p < 0.001). The abnormal rate of DPL I in the affected ear (52/83, 62.65 %) was significantly higher than that in the unaffected ear (7/79, 8.86 %) and the normal left ear (4/106, 3.77 %). We suggest that ischemia of the inner ear might be one of the causes of BPPV and that DPL I may be used to assess the ischemic degree in subjects over 20 years old. PMID:25005432

He, Juan-Wen; Gong, Qiang; Wang, Xue-Feng; Xiao, Zheng

2014-07-01

143

EFFECTS OF LOW TO MODERATE LEAD EXPOSURE ON BRAINSTEM AUDITORY EVOKED POTENTIALS IN CHILDREN  

EPA Science Inventory

Complex auditory processing deficits have been reported in children with asymptomatic lead (Pb) exposure (1,2) as well as acute Pb poisoning (3). Hearing thresholds have not been systematically evaluated in Pb exposed children, although hearing impairments have been observed in P...

144

Hearing Research, 27 (1987) 157-164 Postnatal development of the auditory brainstem response (ABR)  

E-print Network

brainstem response (ABR) in the unanesthetized gerbil * D.I. Smith and N. Kraus Forsythe Laboratory, Siegel brainstem response (ABR) was used to study the development of 8th nerve and auditory brainstem function not follow a strictly sequential pattern. ABR; MLR; Development; Auditory evoked response; Brainstem evoked

145

Preliminary results of the relationship between the binaural interaction component of the electrically evoked auditory brainstem response and interaural pitch comparisons in bilateral cochlear implant recipients  

PubMed Central

Objectives The purpose of this study was to investigate the relationship between electrophysiologic measures of the binaural interaction component (BIC) of the electrically evoked auditory brainstem response (EABR) and psychophysical measures of interaural pitch comparisons in Nucleus bilateral cochlear implant users. Design Data were collected for ten postlingually deafened adult cochlear implant users. Each subject conducted an interaural pitch-comparison task using a biphasic pulse train with a pulse rate of 1000 pulses per second (pps) at high stimulation levels. Stimuli were presented in a two-interval, two-alternative forced-choice procedure with roving current variations. A subgroup of four subjects repeated the task at low stimulation levels. BICs were measured using loudness balanced, biphasic current pulses presented at a rate of 19.9 pps for each subject by pairing the electrode 12 (out of 22 intracochlear electrodes) in the right ear with each of 11 electrodes spaced across the electrode array in the left ear. The BIC was measured at high stimulation levels in ten subjects and at low stimulation levels in seven subjects. Because of differences in stimulation rate used in BIC measures and interaural pitch comparisons, the actual stimulation levels were different in these two measures. The relationship between BIC responses and results of interaural pitch comparisons was evaluated for each of the individual subjects as well as at the group level. Evaluation was carried out separately for results obtained at high and low stimulation levels. Results There was no significant correlation between results of BIC measures and interaural pitch comparisons on either the individual or group levels. Lower stimulation level did not improve the relationship between these two measures. Conclusions No significant correlations between psychophysical measures of interaural pitch comparisons and electrophysiologic measures of the BIC of the EABR were found. The lack of correlation may be attributed to methods used to quantify the data, small number of subjects retested at low stimulation levels, as well as central processing components involved in the interaural pitch-comparison task. PMID:21730858

He, Shuman; Brown, Carolyn J.; Abbas, Paul J.

2011-01-01

146

Classification of evoked potentials by Pearson's correlation in a Brain-Computer Interface  

E-print Network

Classification of evoked potentials by Pearson's correlation in a Brain-Computer Interface F learn- ing technique for use in a brain-computer interface. Electroencephalogram (EEG) signals ac collected from eight individuals. Keywords: Brain-computer interface; BCI; linear classifier; evoked

Paris-Sud XI, Université de

147

Paying attention to orthography: a visual evoked potential study  

PubMed Central

In adult readers, letters, and words are rapidly identified within visual networks to allow for efficient reading abilities. Neuroimaging studies of orthography have mostly used words and letter strings that recruit many hierarchical levels in reading. Understanding how single letters are processed could provide further insight into orthographic processing. The present study investigated orthographic processing using single letters and pseudoletters when adults were encouraged to pay attention to or away from orthographic features. We measured evoked potentials (EPs) to single letters and pseudoletters from adults while they performed an orthographic-discrimination task (letters vs. pseudoletters), a color-discrimination task (red vs. blue), and a target-detection task (respond to #1 and #2). Larger and later peaking N1 responses (~170 ms) and larger P2 responses (~250 ms) occurred to pseudoletters as compared to letters. This reflected greater visual processing for pseudoletters. Dipole analyses localized this effect to bilateral fusiform and inferior temporal cortices. Moreover, this letter-pseudoletter difference was not modulated by task and thus indicates that directing attention to or away from orthographic features did not affect early visual processing of single letters or pseudoletters within extrastriate regions. Paying attention to orthography or color as compared to disregarding the stimuli (target-detection task) elicited selection negativities at about 175 ms, which were followed by a classical N2-P3 complex. This indicated that the tasks sufficiently drew participant's attention to and away from the stimuli. Together these findings revealed that visual processing of single letters and pseudoletters, in adults, appeared to be sensory-contingent and independent of paying attention to stimulus features (e.g., orthography or color). PMID:23734115

Herdman, Anthony T.; Takai, Osamu

2013-01-01

148

Connections of the limbic network: A corticocortical evoked potentials study.  

PubMed

Papez proposed a network for higher brain function, which is termed the limbic network. However, the in vivo human limbic network has not been established. We investigated the connectivity of the human limbic system using corticocortical evoked potential (CCEP). This retrospective analysis included 28 patients with medically intractable focal epilepsy who underwent stereoelectroencephalography (SEEG) and CCEP. Alternating 1 Hz electrical stimuli were delivered to parts of the limbic system [anterior and posterior hippocampus, temporal pole, parahippocampal gyrus (PHG), amygdala, anterior (ACG) and posterior cingulate gyrus (PCG), medial and lateral orbitofrontal cortex (OF)]. A total of 40-60 stimuli were averaged in each trial to obtain CCEP responses. CCEP distributions were evaluated by calculating the root mean square (RMS) of CCEP responses. Anterior hippocampal stimulation elicited prominent CCEP responses in medial and lateral temporal structures, PCG, medial OF and insula over the ipsilateral hemisphere. Posterior hippocampal stimulation induced CCEP responses in the ipsilateral medial and lateral temporal structures and PCG. The findings also revealed connections from temporal pole to the ipsilateral medial temporal structures, and connections from PHG to the ipsilateral hippocampus and PCG. The amygdala projected to broad areas including the ipsilateral medial and lateral temporal structures, medial and lateral frontal areas, the cingulate gyrus, insula and inferior parietal lobule. ACG and PCG showed connections to the ipsilateral medial fronto-parietal areas and connections to bilateral medial temporo-parieto-occipital and lateral parieto-occipital areas, respectively. Medial and lateral OF stimulation induced responses in the adjacent cortices. This study revealed that various regions within the limbic network are intimately connected in reverberating circuits and are linked to specific ipsilateral and contralateral regions, which may reflect distinct functional roles. PMID:25131616

Enatsu, Rei; Gonzalez-Martinez, Jorge; Bulacio, Juan; Kubota, Yuichi; Mosher, John; Burgess, Richard C; Najm, Imad; Nair, Dileep R

2015-01-01

149

Neural origin of evoked potentials during thalamic deep brain stimulation  

PubMed Central

Closed-loop deep brain stimulation (DBS) systems could provide automatic adjustment of stimulation parameters and improve outcomes in the treatment of Parkinson's disease and essential tremor. The evoked compound action potential (ECAP), generated by activated neurons near the DBS electrode, may provide a suitable feedback control signal for closed-loop DBS. The objectives of this work were to characterize the ECAP across stimulation parameters and determine the neural elements contributing to the signal. We recorded ECAPs during thalamic DBS in anesthetized cats and conducted computer simulations to calculate the ECAP of a population of thalamic neurons. The experimental and computational ECAPs were similar in shape and had characteristics that were correlated across stimulation parameters (R2 = 0.80–0.95, P < 0.002). The ECAP signal energy increased with larger DBS amplitudes (P < 0.0001) and pulse widths (P < 0.002), and the signal energy of secondary ECAP phases was larger at 10-Hz than at 100-Hz DBS (P < 0.002). The computational model indicated that these changes resulted from a greater extent of neural activation and an increased synchronization of postsynaptic thalamocortical activity, respectively. Administration of tetrodotoxin, lidocaine, or isoflurane abolished or reduced the magnitude of the experimental and computational ECAPs, glutamate receptor antagonists 6-cyano-7-nitroquinoxaline-2,3-dione (CNQX) and d(?)-2-amino-5-phosphonopentanoic acid (APV) reduced secondary ECAP phases by decreasing postsynaptic excitation, and the GABAA receptor agonist muscimol increased the latency of the secondary phases by augmenting postsynaptic hyperpolarization. This study demonstrates that the ECAP provides information about the type and extent of neural activation generated during DBS, and the ECAP may serve as a feedback control signal for closed-loop DBS. PMID:23719207

Kent, Alexander R.

2013-01-01

150

AMPD2 Regulates GTP Synthesis and is Mutated in a Potentially-Treatable Neurodegenerative Brainstem Disorder  

PubMed Central

Purine biosynthesis and metabolism, conserved in all living organisms, is essential for cellular energy homeostasis and nucleic acids synthesis. The de novo synthesis of purine precursors is under tight negative feedback regulation mediated by adenosine and guanine nucleotides. We describe a new distinct early-onset neurodegenerative condition resulting from mutations in the adenosine monophosphate deaminase 2 gene (AMPD2). Patients have characteristic brain imaging features of pontocerebellar hypoplasia (PCH), due to loss of brainstem and cerebellar parenchyma. We found that AMPD2 plays an evolutionary conserved role in the maintenance of cellular guanine nucleotide pools by regulating the feedback inhibition of adenosine derivatives on de novo purine synthesis. AMPD2 deficiency results in defective GTP-dependent initiation of protein translation, which can be rescued by administration of purine precursors. These data suggest AMPD2-related PCH as a new, potentially treatable early-onset neurodegenerative disease. PMID:23911318

Akizu, Naiara; Cantagrel, Vincent; Schroth, Jana; Cai, Na; Vaux, Keith; McCloskey, Douglas; Naviaux, Robert K.; Vleet, Jeremy Van; Fenstermaker, Ali G.; Silhavy, Jennifer L.; Scheliga, Judith S.; Toyama, Keiko; Morisaki, Hiroko; Sonmez, Fatma Mujgan; Celep, Figen; Oraby, Azza; Zaki, Maha S.; Al-Baradie, Raidah; Faqeih, Eissa; Saleh, Mohammad; Spencer, Emily; Rosti, Rasim Ozgur; Scott, Eric; Nickerson, Elizabeth; Gabriel, Stacey; Morisaki, Takayuki; Holmes, Edward W.; Gleeson, Joseph G.

2013-01-01

151

A Wireless System for Monitoring Transcranial Motor Evoked Potentials  

E-print Network

of ascending sensory signals evoked in peripheral nerves and recorded from peripheral nerve, spinal cord, and sensory cortex. In spine and thoracic surgery, IONM is of critical importance in order to detect early. For instance, com- mercially available IONM systems such as Digitimer (Digitimer Ltd., Welwyn Garden City, UK

Chiao, Jung-Chih

152

Cerebral chemosensory evoked potentials elicited by chemical stimulation of the human olfactory and respiratory nasal mucosa.  

PubMed

A stimulation method was employed by which chemosensory evoked potentials were recorded without tactile somatosensory contamination. The purpose of the study was to determine whether potential components evoked by stimulation of the chemoreceptors of the trigeminal nerve can be distinguished from those of the olfactory nerve. The stimulants (vanillin, phenylethyl alcohol, limonene, menthol, anethol, benzaldehyde, carbon dioxide and a mixture of vanillin and carbon dioxide) were presented in a randomized order to 13 volunteers. Chemosensory evoked potentials to substances which anosmics are unable to perceive (vanillin, phenylethyl alcohol) were termed olfactory evoked potentials; potentials to CO2, which effected no olfactory sensations were termed chemo-somatosensory potentials. Analysis of variance revealed that the different substances resulted in statistically significant changes in the amplitudes and latencies of the evoked potentials, and also in the subjective estimates of intensity. An increased excitation of the somatosensory system resulted in reduced latencies and enhanced amplitudes of the evoked potentials. Responses to the mixture of carbon dioxide and vanillin appeared significantly earlier (50-150 msec) than responses to either substance alone. PMID:2454788

Kobal, G; Hummel, C

1988-01-01

153

Swept contrast visual evoked potentials and their plasticity following monocular deprivation in mice.  

PubMed

The swept contrast visual evoked potential technique is a quasi-psychophysical method that can help bridge the gap between cell biology and visual performance in studies of ocular dominance plasticity. In mice we found that four days of monocular deprivation diminished the amplitude of evoked potentials from the deprived eye relative to the non-deprived eye. This ocular dominance plasticity was nearly as great in adult mice as in juveniles. The monocular deprivation effect was mediated, at least in part, by enhancement of responses evoked from the non-deprived eye, rather than by depression of responses from the deprived eye. PMID:15536006

Lickey, Marvin E; Pham, Tony A; Gordon, Barbara

2004-12-01

154

THE USE OF VISUAL AND CHEMOSENSORY EVOKED POTENTIALS IN ENVIRONMENTAL AND OCCUPATIONAL HEALTH  

EPA Science Inventory

The application of visual (VEP) and chemosensory evoked potentials (CSEP) in occupational and environmental health is briefly reviewed. EPs have been used extensively in experimental neurotoxicology and play an increasing role in human neurotoxicity testing. he similarity of VEP ...

155

EVOKED POTENTIALS AS INDICES OF ADAPTATION IN THE SOMATOSENSORY SYSTEM IN HUMANS: A REVIEW AND PROSPECTUS  

EPA Science Inventory

Population-level behavior of large neural aggregates can be efficiently monitored by corresponding population-level indices such as somatosensory evoked potentials (SEPs). The literature reviewed clearly indicates that SEPs undergo systematic and often marked changes under condit...

156

Chromatic visual evoked potentials in young patients with demyelinating disease.  

PubMed

The purpose of this study was to evaluate color vision in young patients with demyelinating disease both clinically and electrophysiologically. Thirty young patients (8-28 years, mean age 19 years) with demyelinating disease with or without a history of optic neuritis (ON) were investigated. Color vision was evaluated clinically with the Ishihara test and the Farnsworth-Munsell 100 hue (FM 100 hue) test and electrophysiologically with chromatic visual evoked potentials (cVEPs). Color deficiency axis and error score (ES) obtained with the FM 100 hue test were analyzed. cVEPs to isoluminant red-green (R-G) and blue-yellow (B-Y) stimuli were recorded. The stimulus was a 7 deg circle composed of horizontal sinusoidal gratings with a spatial frequency of 2?cycles/deg and 90% chromatic contrast. Onset-offset mode of stimulation (ON:OFF=300?700??ms) was used. Since the majority of the patients were adults (>18??years), the negative wave (N wave) of the cVEP respones is the prominent part and therefore was analyzed. Sixty eyes were studied-22 with at least one episode of ON (ON group) and 38 without any clinically evident episode of ON (nON group). The average ES in the ON group was 179.18±171.8, whereas in the nON group it was 87.60±65.34. The average N-wave latency in the ON group was 144±44??ms for the R-G stimulus and 146±56??ms for the B-Y stimulus, whereas in the nON group, it was 117±13??ms for the R-G stimulus and 121±22??ms for the B-Y one. The average N-wave amplitude in the ON group was 9.3±7.1???V for the R-G stimulus and 5.1±3.9???V for the B-Y one, whereas in the nON group, it was 10.8±8.3???V for the R-G stimulus and 6.4±4.3???V for the B-Y one. A significant difference between the ON and the nON group was found: in the ON group, ES was higher (p=0.01) and N-wave latency was longer (p=0.01) compared with those in the nON group. The study showed that color vision is expectedly more affected in the ON group, but also often in the nON group, which may indicate increased parvocellular visual pathway vulnerability in demyelinating diseases. PMID:24695207

Pompe, Manca Tekav?i?; Brecelj, Jelka; Kranjc, Branka Stirn

2014-04-01

157

Influence of motor unit properties on the size of the simulated evoked surface EMG potential  

Microsoft Academic Search

The purpose of the study was to quantify the influence of selected motor unit properties on the simulated amplitude and area\\u000a of evoked muscle potentials detected at the skin surface. The study was restricted to a motor unit population simulating a\\u000a hand muscle whose potentials were recorded on the skin over the muscle. Peak-to-peak amplitude and area of the evoked

Kevin G. Keenan; Dario Farina; Roberto Merletti; Roger M. Enoka

2006-01-01

158

Evaluation of brain function in acute carbon monoxide poisoning with multimodality evoked potentials  

SciTech Connect

The median nerve somatosensory evoked potentials (SEP), pattern reversal visual evoked potentials (VEP), and brain stem auditory evoked potentials (BAEP) were studied in 109 healthy adults and in 88 patients with acute carbon monoxide (CO) poisoning. The upper limits for normal values of peak and interpeak latencies of multimodalities of evoked potentials in the reference group were established by a stepwise multiple regression analysis. SEP changes selectively affecting N32 and N60 were found in 78.8% of patients. There was prolonged PI00 latency of VEP in 58.2% of the cases examined. The prevalence of BAEP abnormalities in comatose patients (36%) was significantly higher than that (8.6%) in conscious patients. BAEP abnormalities were most frequently seen in comatose patients who had diminished brain stem reflexes (77.8%). It has been found that a consistent abnormality involving N2O and subsequent peaks in SEP, a remarkable prolongation of PI00 latency in VEP, or a prolongation of Ill-V interpeak latency in BAEP as well as the reoccurrence of evoked potential abnormalities after initial recovery all indicate unfavorable outcomes in patients with acute CO poisoning. The multimodality evoked potentials have proved to be sensitive indicators in the evaluation of brain dysfunction and in the prediction of prognosis of acute CO poisoning and the development of delayed encephalopathy. 16 refs., 4 figs., 6 tabs.

He, Fengsheng; Liu, Xibao; Yang, Shi; Zhang, Shoulin (Institute of Occupational Medicine, Beijing (China)); Xu, Guanghua; Fang, Guangchai; Pan, Xiaowen (Navy Hospital, Beijing (China))

1993-02-01

159

Auditory evoked potentials in two short-finned pilot whales (Globicephala macrorhynchus).  

PubMed

The hearing sensitivities of two short-finned pilot whales (Globicephala macrorhynchus) were investigated by measuring auditory evoked potentials generated in response to clicks and sinusoidal amplitude modulated (SAM) tones. The first whale tested, an adult female, was a long-time resident at SeaWorld San Diego with a known health history. Click-evoked responses in this animal were similar to those measured in other echolocating odontocetes. Auditory thresholds were comparable to dolphins of similar age determined with similar evoked potential methods. The region of best sensitivity was near 40 kHz and the upper limit of functional hearing was between 80 and 100 kHz. The second whale tested, a juvenile male, was recently stranded and deemed non-releasable. Click-evoked potentials were not detected in this animal and testing with SAM tones suggested severe hearing loss above 10 kHz. PMID:21361467

Schlundt, Carolyn E; Dear, Randall L; Houser, Dorian S; Bowles, Ann E; Reidarson, Tom; Finneran, James J

2011-02-01

160

Short latency somatosensory evoked potentials in children with autism.  

PubMed

SSEP were recorded in normal volunteer, autism, MBD and MR groups in order to find electrophysiological evidence of a brain lesion. Peak latencies per 1 m body length, P1/H, P2/H and P3/H in MR, and P3/H in autism, were greater than those in normal controls. The values of interpeak latencies per 1 m body length, P1-P3/H and P2-P3/H in autism and MR, were greater than those in normal controls. These in MBD were not different from in normal controls. The cause of the increase in P1/H in MR is unknown. The increases in P1-P3/H and P2-P3/H suggest that in autism and MR there is brainstem dysfunction. It is not clear whether there is a relationship among autism, MBD and MR. PMID:3799913

Hashimoto, T; Tayama, M; Miyao, M

1986-01-01

161

Evoked potential measurement of the masked hearing threshold of a Pacific white-sided dolphin (Lagenorhynchus obliquidens)  

NASA Astrophysics Data System (ADS)

The masked hearing threshold of a Pacific white-sided dolphin (Lagenorhynchus obliquidens) was determined by measuring the animal's auditory brainstem response (ABR). The dolphin was trained to wear surface-contact electrodes embedded in suction cups and to swim into a hoop centered at 1 m below the water surface facing a sound projector 5 m away. Broadband transient signals with center frequencies of 8, 16, 32, 64, 80, and 100 kHz were used as the stimuli. ABR signals were measured by digitizing the electrode signals in 32 point blocks at a sampling rate of 20 kHz. Five hundred blocks were averaged in order to obtain an ABR. The response latency for suprathreshold threshold signals was approximately 1.9 ms with the highest peak-to-peak ABR amplitude of approximately 2.8 uV occurring for a signal frequency of 64 kHz. The spectrum of the ABR signal was similar to that of Tursiops truncatus, with a major peak at 1120 Hz and a secondary peak at 664 Hz. Threshold was determined by progressively reducing the amplitude of the stimulus until an evoked potential could not be detected. The energy signal-to-noise ratio within an integration window at threshold varied between 1 and 8 dB.

Au, Whitlow W. L.; Jeanette, Thomas; Western, A.; Rameriz, Kenneth M.

2003-04-01

162

Linguistic status of timbre influences pitch encoding in the brainstem  

E-print Network

Linguistic status of timbre influences pitch encoding in the brainstem Ananthanarayan Krishnana of this experiment is to assess the effects of the linguistic status of timbre on pitch processing in the brainstem. Brainstem frequency following responses were evoked by the Mandarin high-rising lexical tone superimposed

Dasgupta, Dipankar

163

ORIGINAL RESEARCH Startle evoked movement is delayed in older adults  

E-print Network

ORIGINAL RESEARCH Startle evoked movement is delayed in older adults: implications for brainstem Keywords Aging, brainstem, startle. Correspondence Claire F. Honeycutt, Rehabilitation Institute of Chicago the brainstem. Since the brainstem plays a critical role in motor control throughout the whole body, having

Perreault, Eric J.

164

Vertex evoked potentials in a rating-scale detection task: Relation to signal probability  

NASA Technical Reports Server (NTRS)

Vertex evoked potentials were recorded from human subjects performing in an auditory detection task with rating scale responses. Three values of a priori probability of signal presentation were tested. The amplitudes of the N1 and P3 components of the vertex potential associated with correct detections of the signal were found to be systematically related to the strictness of the response criterion and independent of variations in a priori signal probability. No similar evoked potential components were found associated with signal absent judgements (misses and correct rejections) regardless of the confidence level of the judgement or signal probability. These results strongly support the contention that the form of the vertex evoked response is closely correlated with the subject's psychophysical decision regarding the presence or absence of a threshold level signal.

Squires, K. C.; Squires, N. K.; Hillyard, S. A.

1974-01-01

165

Lumbosacral evoked potentials and vesicourethral function in patients with chronic suprasacral spinal cord injury.  

PubMed Central

Persistent detrusor acontractility despite normal somatic reflex activity in some patients with high spinal cord injury is an enigma. Previous work has suggested disordered integration of afferent activity in sacral roots or the sacral spinal cord. Forty male patients with chronic stable suprasacral cord lesions were studied by filling and voiding videocystometrography, and recording lumbosacral evoked potentials from posterior tibial nerve stimulation. Only five of 15 patients with decreased detrusor contractility had abnormal lumbosacral evoked potentials. Similar abnormalities were found in four of 11 patients with efficient hyperreflexic bladders. The finding of normal lumbosacral evoked potentials in the majority of patients with suprasacral cord injuries and decreased detrusor contractility supports the argument that the pathophysiology of this specific form of neurogenic bladder dysfunction is multifactorial. PMID:2283530

Lucas, M G; Thomas, D G

1990-01-01

166

Mechanisms of human motion perception: combining evidence from evoked potentials, behavioural  

E-print Network

Keywords: computer simulations, evoked potentials, man, motion perception, reaction time, vision Abstract potentials correlate with behavioural measurements like discrimination thresholds and reaction time. Subjects the reaction time. We show here that motion coherence had a strong in¯uence on both amplitude and latency

Zanker, Johannes M.

167

Mechanically evoked cerebral potentials to sudden ankle dorsiflexion in human subjects during standing  

Microsoft Academic Search

Mechanically evoked cerebral potentials (MECP) were studied in humans standing on a movable platform with three different stance widths. A sudden platform tilt of 4° produced ankle dorsiflexion and resulted in scalp potentials of five distinct components, the earliest being a positive deflection at 3560 ms. Their latencies have shown fairly consistent values among the three stance widths, while the

B. Dimitrov; T. Gavrilenko; P. Gatev

1996-01-01

168

Visual evoked potentials, heart rate responses and memory to emotional pictorial stimuli  

Microsoft Academic Search

Although the effects of emotional stimuli on event-related cortical potentials, heart rate, and memory have been extensively studied, the association of these variables in a single study has been neglected. The influence of pleasant, unpleasant, and neutral photographic slides on visual evoked potentials (VEPs), heart rate responses, and free recall, was investigated in 20 normal subjects. VEPs were recorded from

Daniela Palomba; Alessandro Angrilli; Alessio Mini

1997-01-01

169

Ultrasonic evoked responses in rat cochlear nucleus  

PubMed Central

Numerous studies have reported auditory brainstem responses evoked by stimuli within the “normal” hearing range of rats, with maximum sensitivity peaking around 16 kHz. Yet rats also emit and respond to sounds in the ultrasonic (US) frequency range (30-100 kHz). However very few electrophysiological studies have recorded auditory brainstem responses using US stimuli, and none have exceeded 70 kHz. We report here short-latency (1-3 ms) evoked potentials recorded in rat cochlear nucleus (CN) to US stimuli ranging from 40-90 kHz. Robust responses were recorded in 33 of 36 CN recording sites to stimuli ranging from 40-60 kHz; and twenty-eight of these sites continued to yield well defined responses out to 90 kHz. Latencies systematically increased and overall amplitudes decreased with increasing US frequency. Amplitudes differed significantly in the three CN subnuclei, being largest in posterior-ventral (PVCN) and smallest in anterior-ventral (AVCN). The fact that well defined responses can be recorded to stimuli as high as 90 kHz significantly extends the recorded upper frequency range of neural activity in the brainstem auditory pathway of the rat. These evoked potential results agree with the well documented behavioral repertoire of rats in the US frequency range. PMID:17803975

Du, Yi; Ping, Junli; Li, Nanxin; Wu, Xihong; Li, Liang; Galbraith, Gary

2009-01-01

170

Visual evoked potential characterization of rabbit animal model for retinal prosthesis research.  

PubMed

Visual evoked potentials (VEP) are used to confirm the function of prosthetic devices designed to stimulate retinas with damaged photoreceptors in vivo. In this work, we focus on methods and experimental consideration for recording visual evoked potential in rabbit models and assesses the use for retinal prosthesis research. We compare both invasive and noninvasive methods for recording VEPs, the response of the rabbit retina to various light wavelengths and intensities, focal vs. full field stimulation, and the effect of light bleaching on the retinal response. PMID:24110493

Khraiche, Massoud L; El Emam, Sharif; Akinin, Abraham; Cauwenberghs, Gert; Freeman, William; Silva, Gabriel A

2013-01-01

171

Letters to the Editor Reliability of the auditory brainstem responses to speech over one year in  

E-print Network

Letters to the Editor Reliability of the auditory brainstem responses to speech over one year et al., 2012), we provide evidence that the speech-evoked auditory brainstem response (speech of the speech-ABR will probably never reach the levels seen for click-evoked brainstem responses for a variety

172

Predictability of Painful Stimulation Modulates the Somatosensory-Evoked Potential in the Rat  

PubMed Central

Somatosensory-evoked potentials (SEPs) are used in humans and animals to increase knowledge about nociception and pain. Since the SEP in humans increases when noxious stimuli are administered unpredictably, predictability potentially influences the SEP in animals as well. To assess the effect of predictability on the SEP in animals, classical fear conditioning was applied to compare SEPs between rats receiving SEP-evoking electrical stimuli either predictably or unpredictably. As in humans, the rat’s SEP increased when SEP-evoking stimuli were administered unpredictably. These data support the hypothesis that the predictability of noxious stimuli plays a distinctive role in the processing of these stimuli in animals. The influence of predictability should be considered when studying nociception and pain in animals. Additionally, this finding suggests that animals confronted with (un)predictable noxious stimuli can be used to investigate the mechanisms underlying the influence of predictability on central processing of noxious stimuli. PMID:23613862

Schaap, Manon W. H.; van Oostrom, Hugo; Doornenbal, Arie; Baars, Annemarie M.; Arndt, Saskia S.; Hellebrekers, Ludo J.

2013-01-01

173

Cannabinoid 1 and transient receptor potential vanilloid 1 receptors discretely modulate evoked glutamate separately from spontaneous glutamate transmission.  

PubMed

Action potentials trigger synaptic terminals to synchronously release vesicles, but some vesicles release spontaneously. G-protein-coupled receptors (GPCRs) can modulate both of these processes. At cranial primary afferent terminals, the GPCR cannabinoid 1 (CB1) is often coexpressed with transient receptor potential vanilloid 1 (TRPV1), a nonselective cation channel present on most afferents. Here we tested whether CB1 activation modulates synchronous, action potential-evoked (eEPSCs) and/or spontaneous (sEPSCs) EPSCs at solitary tract nucleus neurons. In rat horizontal brainstem slices, activation of solitary tract (ST) primary afferents generated ST-eEPSCs that were rapidly and reversibly inhibited from most afferents by activation of CB1 with arachidonyl-2'-chloroethylamide (ACEA) or WIN 55,212-2 [R-(+)-(2,3-dihydro-5-methyl-3-[(4-morpholinyl)methyl]pyrrolo[1,2,3-de]-1,4-benzoxazin-6-yl)(1-naphthalenyl) methanone monomethanesulfonate]. The CB1 antagonist/inverse agonist AM251 [N-1-(2,4-dichlorophenyl)-5-(4-iodophenyl)-4-methyl-N-1-piperidinyl-1H-pyrazole-3-carboxamide] blocked these responses. Despite profound depression of ST-eEPSCs during CB1 activation, sEPSCs in these same neurons were unaltered. Changes in temperature changed sEPSC frequency only from TRPV1(+) afferents (i.e., thermal sEPSC responses only occurred in TRPV1(+) afferents). CB1 activation failed to alter these thermal sEPSC responses. However, the endogenous arachidonate metabolite N-arachidonyldopamine (NADA) promiscuously activated both CB1 and TRPV1 receptors. NADA inhibited ST-eEPSCs while simultaneously increasing sEPSC frequency, and thermally triggered sEPSC increases in neurons with TRPV1(+) afferents. We found no evidence for CB1/TRPV1 interactions suggesting independent regulation of two separate vesicle pools. Together, these data demonstrate that action potential-evoked synchronous glutamate release is modulated separately from TRPV1-mediated glutamate release despite coexistence in the same central terminations. This two-pool arrangement allows independent and opposite modulation of glutamate release by single lipid metabolites. PMID:24920635

Fawley, Jessica A; Hofmann, Mackenzie E; Andresen, Michael C

2014-06-11

174

Self-Modeling Structure of Evoked Postsynaptic Potentials  

E-print Network

potentials (EPSPs) that are quantal in nature. The method is called self-modeling regression, known in the statistics literature as SEMOR. This method illustrates that the differing timing and heights of EPSPs can of ``shape'' in an excitatory postsynaptic potential (EPSP) by illustrating a ``self- modeling'' proper

Cooper, Robin L.

175

STATIONARY PATTERN ADAPTATION AND THE EARLY COMPONENTS IN HUMAN VISUAL EVOKED POTENTIALS  

EPA Science Inventory

Pattern-onset visual evoked potentials were elicited from humans by sinusoidal gratings of 0.5., 1, 2 and 4 cpd (cycles/degree) following adaptation to a blank field or one of the gratings. The wave forms recorded after blank field adaptation showed an early positive component, P...

176

A Steady State Visually Evoked Potential Investigation of Memory and Ageing  

ERIC Educational Resources Information Center

Old age is generally accompanied by a decline in memory performance. Specifically, neuroimaging and electrophysiological studies have revealed that there are age-related changes in the neural correlates of episodic and working memory. This study investigated age-associated changes in the steady state visually evoked potential (SSVEP) amplitude and…

Macpherson, Helen; Pipingas, Andrew; Silberstein, Richard

2009-01-01

177

Intelligence and Complexity of the Averaged Evoked Potential: An Attentional Theory.  

ERIC Educational Resources Information Center

A study measuring average evoked potentials in 21 college students finds that intelligence test scores correlate significantly with the difference between string length in attended and nonattended conditions, a finding that suggests that previous inconsistencies in reporting string length-intelligence correlations may have resulted from confound…

Bates, Tim; And Others

1995-01-01

178

A modified mirror projection visual evoked potential stimulator for presenting patterns in different orientations.  

PubMed

Modifications to a standard mirror projection visual evoked potential stimulator are described to enable projection of patterns in varying orientations. The galvanometer-mirror assembly is mounted on an arm which can be rotated through 90 degrees. This enables patterns in any orientation to be deflected perpendicular to their axes. PMID:2424725

Taylor, P K; Wynn-Williams, G M

1986-07-01

179

Mismatched Negativity in Evoked Potentials at Short-Term Acoustic Stimulation  

Microsoft Academic Search

Mismatched negativity (MMN) is a special kind of endogenous evoked potentials, which is related to the mechanisms of involuntary attention. MMN is recorded each time when the acoustic signal differs from the standard stimuli of some parameters such as duration, frequency, or intensity [1]. In this case, the MMN parameters do not depend on whether the test subject is aware

A. A. Aleksandrov; M. E. Babanin

2000-01-01

180

Enhancement of Neuroplastic P2 and N1c Auditory Evoked Potentials in Musicians  

Microsoft Academic Search

P2 and N1c components of the auditory evoked potential (AEP) have been shown to be sensitive to remodeling of the auditory cortex by training at pitch discrimination in nonmusician subjects. Here, we investigated whether these neuroplastic components of the AEP are enhanced in musicians in accordance with their musical training histories. Highly skilled violinists and pianists and nonmusician controls listened

Antoine Shahin; Daniel J. Bosnyak; Laurel J. Trainor; Larry E. Roberts

2003-01-01

181

Pattern-Reversal Visual-Evoked Potentials in Patients with Hemineglect Syndrome  

Microsoft Academic Search

To investigate basic visual information processing in patients with hemineglect syndrome, pattern reversal visual evoked potentials (VEPs) were recorded in 21 brain-injured patients (10 with neglect symptoms) and 6 healthy subjects. The stimulus was a checkerboard which varied in check size or temporal frequency, presented to the left or right Visual field. VEPs recorded in neglect patients to stimuli presented

M. P. Viggiano; D. Spinelli; L. Mecacci

1995-01-01

182

FOCAL LESIONS OF VISUAL CORTEX: EFFECTS ON VISUAL EVOKED POTENTIALS IN RATS  

EPA Science Inventory

Focal lesions were placed in the visual cortex of Long-Evans hooded rats, immediately below skull screw recording electrodes. Lesions were produced by heat and extended an average depth of about 0.9 mm below the cortical surface. Evoked potentials recorded from the electrode over...

183

Analysis of gender based differences in auditory evoked potentials among healthy elderly population  

PubMed Central

Background: Influence of gender on auditory evoked potentials is contentious. Although there are quite a few studies documenting the gender as an influencing factor on auditory evoked potentials in younger subjects, but there is a lack of similar studies among elderly population. The present study was conducted to find out the pattern of gender based differences in auditory evoked potentials among healthy elderly subjects. Materials and Methods: A cross-sectional study was conducted on age matched, healthy males (n = 35) and females (n = 34), aged 50-70 years. The measures included latencies of waves I-V and interpeak latencies (IPL) I-III, III-V and I-V separately for both ears. Data was analyzed statistically using Students unpaired t-test, using Statistical Package for Social Sciences software v13.0. Results: The values of all the latencies and IPL for both the ears were non-significantly higher (P > 0.05) in males as compared to females. These results may be attributed to the differences in head circumference between both the genders and to the changed hormonal milieu of sex hormones after menopause. Conclusions: Statistical insignificance of latencies among male and female elderly subjects excludes gender as an influencing factor on auditory evoked potentials in this age group. PMID:25371865

Gupta, Sharat; Mittal, Shallu; Baweja, Pooja; Kumar, Avnish; Singh, Kamal Dev; Sharma, Raghuvansh

2014-01-01

184

WITHIN-SESSION CHANGES IN PEAK N160 AMPLITUDE OF FLASH EVOKED POTENTIALS IN RATS  

EPA Science Inventory

The negative peak occurring approximately 160 msec after stimulation (peak N 160) flash evoked potentials (FEPS) of rats changes with repeated testing. abituation, sensitization, and arousal have all been invoked to explain these changes, but few studies have directly tested thes...

185

EFFECTS OF TRANSCRANIAL DIRECT CURRENT STIMULATION (tDCS) ON SENSORY EVOKED POTENTIALS: A COMPUTATIONAL MODELING  

E-print Network

EFFECTS OF TRANSCRANIAL DIRECT CURRENT STIMULATION (tDCS) ON SENSORY EVOKED POTENTIALS/computational modeling approach aimed at studying the effects of transcranial Direct Current Stimulation (tDCS (EPs) recorded from the somatosensory cortex of the rabbit under tDCS. Results showed that the model

Paris-Sud XI, Université de

186

Simultaneous recording of late and ultra-late pain evoked potentials in fibromyalgia  

Microsoft Academic Search

Objective: To characterize laser evoked potentials (LEP), pain psychophysics and local tissue response in fibromyalgia patients.Methods: LEP were recorded in 14 women with fibromyalgia in response to bilateral stimulation of tender and control points in upper limbs by 4 blocks of 20 stimuli at each point. Subsequently, heat pain thresholds were measured and supra-threshold magnitude estimations of heat pain stimuli

M Granot; D Buskila; Y Granovsky; E Sprecher; L Neumann; D Yarnitsky

2001-01-01

187

ALTERATIONS IN FLASH EVOKED POTENTIALS (FEPS) IN RATS PRODUCED BY 3,3'-IMINODIPROPIONITRILE (IDPN)  

EPA Science Inventory

-3,-3'-iminodiproprionitrile (IDPN) is a neurotoxicant that produces changes in flash evoked potentials (FEPs) 18 weeks after treatment (52). e examined dose and time-related effects of IDPN on FEPs at earlier time points than previously studied. dult male Long-Evans rats were gi...

188

Distortion Product Otoacoustic Emissions and Auditory Evoked Potentials in the Hedgehog Tenrec, Echinops telfairi  

Microsoft Academic Search

The hedgehog tenrec, Echinops telfairi, has certain basal mammalian features, like a cloaca and a sparsely differentiated brain with smooth cerebral hemispheres. The peripheral auditory capabilities of this species were investigated by means of distortion product otoacoustic emissions (DPOAE). For comparison, we determined auditory evoked potentials (AEP) in the inferior colliculus and the auditory cortex. Both methods show that the

Markus Drexl; Michael Faulstich; Boris von Stebut; Manfred Kössl

2003-01-01

189

Deep hypothermic circulatory arrest: II. Changes in electroencephalogram and evoked potentials during rewarming  

Microsoft Academic Search

Background. Electrophysiologic studies during rewarming after deep hypothermic circulatory arrest probe the state of the brain during this critical period and may provide insight into the neurological effects of circulatory arrest and the neurologic outcome.Methods. Electroencephalogram (EEG) and evoked potentials were monitored during rewarming in 109 patients undergoing aortic surgery with hypothermic circulatory arrest.Results. The sequence of neurophysiologic events during

Mark M Stecker; Albert T Cheung; Alberto Pochettino; Glenn P Kent; Terry Patterson; Stuart J Weiss; Joseph E Bavaria

2001-01-01

190

Vestibular evoked myogenic potentials in benign paroxysmal positional vertigo and Meniere’s disease  

Microsoft Academic Search

The objective was to investigate vestibular evoked myogenic potentials (VEMP) in benign paroxysmal positional vertigo (BPPV) and Meniere’s disease, and to determine if this type of testing is valuable for assessing the vestibular system. A prospective controlled clinical study was designed in a tertiary referral center setting. The 62 participants included 17 healthy controls and 45 other subjects selected from

Güzin Akkuzu; Babur Akkuzu; Levent N. Ozluoglu

2006-01-01

191

"P300 SPELLER" BRAIN-COMPUTER INTERFACE: ENHANCEMENT OF P300 EVOKED POTENTIAL BY SPATIAL FILTERS  

E-print Network

"P300 SPELLER" BRAIN-COMPUTER INTERFACE: ENHANCEMENT OF P300 EVOKED POTENTIAL BY SPATIAL FILTERS, Lyon, F-69000, France ABSTRACT Brain-Computer Interfaces (BCI) are communication sys- tems that use brain activity to control a computer or other devices. The BCI system described in this study is based

Paris-Sud XI, Université de

192

Steady State Visual Evoked Potential (SSVEP) -based Brain Spelling System with Synchronous and Asynchronous Typing Modes  

E-print Network

, 3000 Leuven, Belgium Abstract -- The paper presents an EEG-based wireless brain-computer interface (BCI and asynchronous modes. Keywords -- brain-computer interface, mind speller, steady- state visual evoked potentials, synchronous and asynchronous spelling I. INTRODUCTION Research on brain-computer interfaces (BCIs) has wit

193

xDAWN Algorithm to Enhance Evoked Potentials: Application to Brain Computer Interface  

E-print Network

1 xDAWN Algorithm to Enhance Evoked Potentials: Application to Brain Computer Interface Bertrand, France. Abstract--A brain-computer interface (BCI) is a communica- tion system which allows to control interface, P300-speller, xDAWN algorithm, spatial enhancement. I. INTRODUCTION Brain-Computer Interfaces

Paris-Sud XI, Université de

194

Multiple Channel Detection of Steady-State Visual Evoked Potentials for Brain-Computer Interfaces  

Microsoft Academic Search

In this paper, novel methods for detecting steady-state visual evoked potentials using multiple electroencephalogram (EEG) signals are presented. The methods are tailored for brain-computer interfacing, where fast and accurate detection is of vital importance for achieving high information transfer rates. High detection accuracy using short time segments is obtained by finding combinations of electrode signals that cancel strong interference signals

Ola Friman; Ivan Volosyak; Axel Graser

2007-01-01

195

Attentional Modulation of Visual-Evoked Potentials by Threat: Investigating the Effect of Evolutionary Relevance  

ERIC Educational Resources Information Center

In dot-probe tasks, threatening cues facilitate attention to targets and enhance the amplitude of the target P1 peak of the visual-evoked potential. While theories have suggested that evolutionarily relevant threats should obtain preferential neural processing, this has not been examined empirically. In this study we examined the effects of…

Brown, Christopher; El-Deredy, Wael; Blanchette, Isabelle

2010-01-01

196

ACUTE EFFECTS OF ETHANOL ON PATTERN REVERSAL AND FLASH-EVOKED POTENTIALS IN RATS AND THE RELATIONSHIP TO BODY TEMPERATURE  

EPA Science Inventory

The effects of acute ethanol treatment on flash and pattern reversal visual evoked potentials (FEPs and PREPs, respectively) were examined in three experiments using Long-Evans rats. The relationships of evoked potential parameters with blook ethanol concentration and body temper...

197

ALTERATIONS IN RAT FLASH AND PATTERN REVERSAL EVOKED POTENTIALS AFTER ACUTE OR REPEATED ADMINISTRATION OF CARBON DISULFIDE (CS2)  

EPA Science Inventory

Because solvents may selectively alter portions of visual evoked potentials, we examined the effects of carbon disulfide (CS2) on flash (FEPs) and pattern reversal (PREPs) evoked potentials. Long-Evans rats were administered (ip) carbon disulfide (CS2) either acutely or for 30 da...

198

Maturation of Peripheral and Brainstem Auditory Function in the First Year Following Perinatal Asphyxia: A Longitudinal Study.  

ERIC Educational Resources Information Center

A study of 44 infants who suffered asphyxia during the perinatal period examined the influence of perinatal asphyxia on the maturation of auditory pathways by serial recordings of the brainstem auditory evoked potentials (BAEP). The general maturational course of the BAEP following asphyxia was similar to a control group. (Author/CR)

Jiang, Ze D.

1998-01-01

199

Different brain potentials evoked at distinct phases of rule learning.  

PubMed

The neural mechanisms of rule learning are of interest to cognitive neuroscientists, but the time course of rule induction and the related brain potential remain unclear. In this study, event-related brain potentials (ERPs) were measured during the distinct phases of rule induction. Participants in two experiments were presented with a series of Arabic numbers and were asked to detect the hidden rules. The ERP results revealed that (a) the rule-discovery trials elicited a larger P3 component than the nondiscovery trials, reflecting the initial identification of the regularity of number series, and (b) when a new instance was incongruent with the previously acquired rule, a larger N2 and enhanced late positive component were elicited, reflecting the process of mismatch detection and the updating of working memory context. PMID:22804836

Li, Fuhong; Cao, Bihua; Gao, Heming; Kuang, Li; Li, Hong

2012-09-01

200

Stimulus novelty, task relevance and the visual evoked potential in man  

NASA Technical Reports Server (NTRS)

The effect of task relevance on P3 (waveform of human evoked potential) waves and the methodologies used to deal with them are outlined. Visual evoked potentials (VEPs) were recorded from normal adult subjects performing in a visual discrimination task. Subjects counted the number of presentations of the numeral 4 which was interposed rarely and randomly within a sequence of tachistoscopically flashed background stimuli. Intrusive, task-irrelevant (not counted) stimuli were also interspersed rarely and randomly in the sequence of 2s; these stimuli were of two types: simples, which were easily recognizable, and novels, which were completely unrecognizable. It was found that the simples and the counted 4s evoked posteriorly distributed P3 waves while the irrelevant novels evoked large, frontally distributed P3 waves. These large, frontal P3 waves to novels were also found to be preceded by large N2 waves. These findings indicate that the P3 wave is not a unitary phenomenon but should be considered in terms of a family of waves, differing in their brain generators and in their psychological correlates.

Courchesne, E.; Hillyard, S. A.; Galambos, R.

1975-01-01

201

Measurement of evoked potential in recognition of faces and buildings.  

PubMed

In the functional neuro-imaging, it is known that the activation to the second stimulus is suppressed when two stimuli are given successively with a short interval as sensory inputs. This kind of suppressive phenomenon has been observed in event-related potential (ERP) signals as well as functional MRI signals of primary auditory, somatosensory and visual cortices. However, we rarely find reports to ERP suppression in higher-order areas of the brain. In this study we used a paired stimulus paradigm. The paired stimulus paradigm consisted of successively presented two stimuli in one trial. We recorded ERP related to recognition of faces and buildings to investigate the suppressive phenomenon in higher-order areas of the brain. We used the paired stimulus paradigm which was comprised of face, building and gray-colored-plain (gray) pictures. The inter-stimulus interval of two stimuli was 200 ms. On the points of O2 and T6, we observed that the ERP for the latter stimulus (face picture) was suppressed severely when a face-gray stimulus pair was presented. On the other hand, when a gray-building stimulus pair was presented, the ERP for the latter stimulus (building picture) was not suppressed on the points of O2 and T6. The similar suppression was observed with a face-face stimulus pair. PMID:19163620

Fujiyama, Saki; Sung, Yul-Wan; Ogawa, Seiji; Hayami, Takehito; Iramina, Keiji

2008-01-01

202

Steady-state evoked potentials possibilities for mental-state estimation  

NASA Technical Reports Server (NTRS)

The use of the human steady-state evoked potential (SSEP) as a possible measure of mental-state estimation is explored. A method for evoking a visual response to a sum-of-ten sine waves is presented. This approach provides simultaneous multiple frequency measurements of the human EEG to the evoking stimulus in terms of describing functions (gain and phase) and remnant spectra. Ways in which these quantities vary with the addition of performance tasks (manual tracking, grammatical reasoning, and decision making) are presented. Models of the describing function measures can be formulated using systems engineering technology. Relationships between model parameters and performance scores during manual tracking are discussed. Problems of unresponsiveness and lack of repeatability of subject responses are addressed in terms of a need for loop closure of the SSEP. A technique to achieve loop closure using a lock-in amplifier approach is presented. Results of a study designed to test the effectiveness of using feedback to consciously connect humans to their evoked response are presented. Findings indicate that conscious control of EEG is possible. Implications of these results in terms of secondary tasks for mental-state estimation and brain actuated control are addressed.

Junker, Andrew M.; Schnurer, John H.; Ingle, David F.; Downey, Craig W.

1988-01-01

203

The cannabinoid WIN 55,212-2 inhibits transient receptor potential vanilloid 1 (TRPV1) and evokes  

E-print Network

The cannabinoid WIN 55,212-2 inhibits transient receptor potential vanilloid 1 (TRPV1) and evokes, 2006) Cannabinoids can evoke antihyperalgesia and antinociception at a peripheral site of action the hypothesis that certain cannabinoids directly inhibit peripheral capsaicin-sensitive nociceptive neurons

Price, Theodore

204

IEEE TRANSACTIONS ON BIOMEDICAL ENGINEERING, VOL. 48, NO. 5, MAY 2001 501 Noise Reduction in Brain Evoked Potentials Based on  

E-print Network

--Autocorrelation function (ACF), brain evoked po- tentials (EPs), matched filtering, signal enhancement, thirdIEEE TRANSACTIONS ON BIOMEDICAL ENGINEERING, VOL. 48, NO. 5, MAY 2001 501 Noise Reduction in Brain technique for the recovery of brain evoked potentials (EPs). The main idea behind the presented technique

Cichocki, Andrzej

205

Topography of middle-latency somatosensory evoked potentials following painful laser stimuli and non-painful electrical stimuli.  

PubMed

The aim of this study was to compare cerebral evoked potentials following selective activation of A beta and A delta fibers. In 15 healthy subjects, A beta fibers were activated by electrical stimulation of the left radial nerve at the wrist. A delta fibers were activated by short painful radiant heat pulses, applied to the dorsum of the left hand by a CO2 laser. Evoked potentials were recorded with 15-27 scalp electrodes, evenly distributed over both hemispheres (bandpass 0.5-200 Hz). The laser-evoked potentials exhibited a component with a mean peak latency of 176 msec (N170). Its scalp topography showed a parieto-temporal maximum contralateral to the stimulus side. In contrast, the subsequent vertex negativity (N240), which appeared about 60 msec later, had a symmetrical scalp distribution. Electrically evoked potentials showed a component at 110 msec (N110), that had a topography similar to the laser-evoked N170. The topographies of the N170 and N110 suggest that they may both be generated in the secondary somatosensory cortex. There was no component in the electrically evoked potential that had a comparable interpeak latency to the following vertex potential: for N60 it was longer, for N110 it was shorter. On the other hand, in the laser-evoked potentials no component could be identified the topography of which corresponded to the primary cortical component N20 following electrical stimulation. PMID:7688283

Kunde, V; Treede, R D

1993-01-01

206

Long latency auditory evoked potentials in children with cochlear implants: systematic review.  

PubMed

The aim of this study was to analyze the findings on Cortical Auditory Evoked Potentials in children with cochlear implant through a systematic literature review. After formulation of research question and search of studies in four data bases with the following descriptors: electrophysiology (eletrofisiologia), cochlear implantation (implante coclear), child (criança), neuronal plasticity (plasticidade neuronal) and audiology (audiologia), were selected articles (original and complete) published between 2002 and 2013 in Brazilian Portuguese or English. A total of 208 studies were found; however, only 13 contemplated the established criteria and were further analyzed; was made data extraction for analysis of methodology and content of the studies. The results described suggest rapid changes in P1 component of Cortical Auditory Evoked Potentials in children with cochlear implants. Although there are few studies on the theme, cochlear implant has been shown to produce effective changes in central auditory path ways especially in children implanted before 3 years and 6 months of age. PMID:24626971

Silva, Liliane Aparecida Fagundes; Couto, Maria Inês Vieira; Matas, Carla Gentile; Carvalho, Ana Claudia Martinho de

2013-11-25

207

Evoked potential correlates of selective attention with multi-channel auditory inputs  

NASA Technical Reports Server (NTRS)

Ten subjects were presented with random, rapid sequences of four auditory tones which were separated in pitch and apparent spatial position. The N1 component of the auditory vertex evoked potential (EP) measured relative to a baseline was observed to increase with attention. It was concluded that the N1 enhancement reflects a finely tuned selective attention to one stimulus channel among several concurrent, competing channels. This EP enhancement probably increases with increased information load on the subject.

Schwent, V. L.; Hillyard, S. A.

1975-01-01

208

Some thoughts on the interpretation of steady-state evoked potentials  

Microsoft Academic Search

Steady-state evoked potentials are popular due to their easy analysis in frequency space and the availability of methods for\\u000a objective response detection. However, the interpretation of steady-state responses can be challenging due to their origin\\u000a as a sequence of responses to single stimuli. In the present paper, issues of signal extinction and some characteristics of\\u000a higher harmonics are illustrated based

Sven P. Heinrich

2010-01-01

209

Human cerebral potentials evoked by CO 2 laser stimuli causing pain  

Microsoft Academic Search

Brief radiant heat pulses, generated by a CO2 laser, were used to activate slowly conducting afferents in the hairy skin in man. In order to isolate C-fibre responses a preferential A-fibre block was applied by pressure to the radial nerve at the wrist. Stimulus estimation and evoked cerebral potentials (EP), as well as reaction times, motor and sudomotor activity were

B. Bromm; R.-D. Treede

1987-01-01

210

Effects of Lactate-Induced Panic Attacks on Brain Stem Auditory Evoked Potentials  

Microsoft Academic Search

As the clinical symptomatology of panic attacks may be conceivably related to abnormal brain stem activity, the present study examined the effect of lactate-precipitated panic on brain stem auditory evoked potentials (BSAEPs). The subjects were 27 patients who met DSM-III criteria for panic disorder (Pd), agoraphobia with panic attacks (AgPa) or agoraphobia (Ag). Following drug washout, patients were tested in

Verner J Knott; Yvon D. Lapierre

1986-01-01

211

Spinal function monitoring by evoked spinal cord potentials in aortic aneurysm surgery  

Microsoft Academic Search

Evoked spinal cord potentials (ESCPs) were monitored in 12 patients who underwent repair of thoracoabdominal aortic aneurysm\\u000a with a high risk of spinal ischemia. A pair of bipolar catheter electrodes were introduced into the epidural space, one at\\u000a the level of the C5-T2 vertebrae and the other at the level of T11-L2. Conductive mixed ESCP in seven patients, conductive\\u000a sensory

Tatsuhiko Kano; Michiaki Sadanaga; Morimasa Matsumoto; Yoshihiro Ikuta; Hidehiro Sakaguchi; Hiraaki Gotoh; Yoshimasa Miyauchi

1995-01-01

212

Electrocorticogram spectral analysis and somatosensory evoked potentials as tools to assess electrical stunning efficiency in ducks  

Microsoft Academic Search

1. Fast Fourier transformations (FFTs) of electrocorticogram (ECoG) signals and averaging of somatosensory evoked potentials (SEPs) were used for assessing the impact of electrical stunning of ducks in a waterbath set to deliver a constant current of 150 mA, 600?Hz alternating current (AC) for 4?s. The effectiveness of stunning was determined on the basis of induction of epileptiform activity in

C. Beyssen; R. Babile; X. Fernandez

2004-01-01

213

Facial nerve motor-evoked potential monitoring during microvascular decompression for hemifacial spasm  

Microsoft Academic Search

ObjectiveTo determine whether monitoring facial nerve motor-evoked potentials (FNMEPs) elicited by transcranial electrical stimulation during microvascular decompression (MVD) for hemifacial spasm (HFS) is useful for predicting postoperative outcome.MethodsThe authors analysed FNMEP findings in 25 patients with HFS. Corkscrew electrodes positioned at C3 or C4 and Cz were used to deliver supramaximal stimuli (152–450 V). FNMEPs were recorded from the orbicularis

Masafumi Fukuda; Makoto Oishi; Tetsuya Hiraishi; Yukihiko Fujii

2010-01-01

214

Intraoperative facial motor evoked potential monitoring with transcranial electrical stimulation during skull base surgery  

Microsoft Academic Search

Objective: To address the limitations of standard electromyography (EMG) facial nerve monitoring techniques by exploring the novel application of multi-pulse transcranial electrical stimulation (mpTES) to myogenic facial motor evoked potential (MEP) monitoring.Methods: In 76 patients undergoing skull base surgery, mpTES was delivered through electrodes 1cm anterior to C1 and C2 (M1–M2), C3 and C4 (M3–M4) or C3 or C4 and

Charles C. J. Dong; David B. MacDonald; Ryojo Akagami; Brian Westerberg; Ahmed AlKhani; Imad Kanaan; Maher Hassounah

2005-01-01

215

Abnormal subcortical somatosensory evoked potentials indicate high cervical myelopathy in achondroplasia  

Microsoft Academic Search

Children with achondroplasia may have high cervical myelopathy due to stenosis of the cranio-cervical junction resulting\\u000a in neurological disability and an increased rate of sudden death. To detect myelopathy we recorded somatosensory evoked potentials\\u000a (SEPs) after median nerve stimulation in 30 patients with achondroplasia aged 13 months to 18 years (mean 6 years). In addition\\u000a to the conventional technique of

R. Boor; G. Fricke; K. Brühl; J. Spranger

1999-01-01

216

Stimulus-evoked potentials contribute to map the epileptogenic zone during stereo-EEG presurgical monitoring.  

PubMed

Presurgical monitoring with intracerebral electrodes in patients with drug-resistant focal epilepsy represents a standard invasive procedure to localize the sites of seizures origin, defined as the epileptogenic zone (EZ). During presurgical evaluation, intracerebral single-pulse electrical stimulation (SPES) is performed to define the boundaries of eloquent areas and to evoke seizure-associated symptoms. Extensive intracranial exploration and stimulation generate a large dataset on brain connectivity that can be used to improve EZ detection and to understand the organization of the human epileptic brain. We developed a protocol to analyse field responses evoked by intracranial stimulation. Intracerebral recordings were performed with 105-162 recording sites positioned in fronto-temporal regions in 12 patients with pharmacoresistant focal epilepsy. Recording sites were used for bipolar SPES at 1 Hz. Reproducible early and late phases (<60 ms and 60-500 ms from stimulus artefact, respectively) were identified on averaged evoked responses. Phase 1 and 2 responses recorded at all and each recording sites were plotted on a 3D brain reconstructions. Based on connectivity properties, electrode contacts were primarily identified as receivers, mainly activators or bidirectional. We used connectivity patterns to construct networks and applied cluster partitioning to study the proprieties between potentials evoked/stimulated in different regions. We demonstrate that bidirectional connectivity during phase 1 is a prevalent feature that characterize contacts included in the EZ. This study shows that the application of an analytical protocol on intracerebral stimulus-evoked recordings provides useful information that may contribute to EZ detection and to the management of surgical-remediable epilepsies. PMID:24706574

Boido, Davide; Kapetis, Dimos; Gnatkovsky, Vadym; Pastori, Chiara; Galbardi, Barbara; Sartori, Ivana; Tassi, Laura; Cardinale, Francesco; Francione, Stefano; de Curtis, Marco

2014-09-01

217

Effects of Consonant-Vowel Transitions in Speech Stimuli on Cortical Auditory Evoked Potentials in Adults  

PubMed Central

We examined the neural activation to consonant-vowel transitions by cortical auditory evoked potentials (AEPs). The aim was to show whether cortical response patterns to speech stimuli contain components due to one of the temporal features, the voice-onset time (VOT). In seven normal-hearing adults, the cortical responses to four different monosyllabic words were opposed to the cortical responses to noise stimuli with the same temporal envelope as the speech stimuli. Significant hemispheric asymmetries were found for speech but not in noise evoked potentials. The difference signals between the AEPs to speech and corresponding noise stimuli revealed a significant negative component, which correlated with the VOT. The hemispheric asymmetries can be referred to rapid spectral changes. The correlation with the VOT indicates that the significant component in the difference signal reflects the perception of the acoustic change within the consonant-vowel transition. Thus, at the level of automatic processing, the characteristics of speech evoked potentials appear to be determined primarily by temporal aspects of the eliciting stimuli. PMID:21643536

Doellinger, Michael; Burger, Martin; Hoppe, Ulrich; Bosco, Enrico; Eysholdt, Ulrich

2011-01-01

218

Laser acupuncture - innovative basic research: visual and laser-induced evoked potentials  

PubMed Central

Background and aims: Laser acupuncture is a therapeutic medical method. Innovative basic research is necessary within this fascinating area of research. This publication focuses on visual evoked potentials (VEP) elucidated by non-invasive and partially non-perceptible laser stimulation. Materials (Subjects) and Methods: The first part of this study presents systematic VEP-monitoring in connection with laser acupuncture and manual needle acupuncture in 40 healthy volunteers. The second part deals with bilateral non-perceptible laser needle (658 nm, 40 mW, 500 µm, 1 Hz) irradiation of the Neiguan acupoint (PC6) in a 26-year-old female healthy volunteer using a new 32-channel evoked potential analysis technique. Results: We were not able to find significant changes in latency or amplitudes of VEPs during laser acupuncture within the first part of the study. However in the second part we report about human cerebral evoked potentials after non-perceptible laser stimulation. Conclusions: The findings indicate that exposure to laser needle stimulation with a frequency of 1 Hz can modulate the ascending reticular activating system. Further studies are necessary to confirm or refute the very interesting findings. PMID:24511198

2012-01-01

219

The Auditory Brain-Stem Response to Complex Sounds: A Potential Biomarker for Guiding Treatment of Psychosis  

PubMed Central

Cognitive deficits limit psychosocial functioning in schizophrenia. For many patients, cognitive remediation approaches have yielded encouraging results. Nevertheless, therapeutic response is variable, and outcome studies consistently identify individuals who respond minimally to these interventions. Biomarkers that can assist in identifying patients likely to benefit from particular forms of cognitive remediation are needed. Here, we describe an event-related potential (ERP) biomarker – the auditory brain-stem response (ABR) to complex sounds (cABR) – that appears to be particularly well-suited for predicting response to at least one form of cognitive remediation that targets auditory information processing. Uniquely, the cABR quantifies the fidelity of sound encoded at the level of the brainstem and midbrain. This ERP biomarker has revealed auditory processing abnormalities in various neurodevelopmental disorders, correlates with functioning across several cognitive domains, and appears to be responsive to targeted auditory training. We present preliminary cABR data from 18 schizophrenia patients and propose further investigation of this biomarker for predicting and tracking response to cognitive interventions. PMID:25352811

Tarasenko, Melissa A.; Swerdlow, Neal R.; Makeig, Scott; Braff, David L.; Light, Gregory A.

2014-01-01

220

A visual study of surface potentials and Laplacians due to distributed neocortical sources: computer simulations and evoked potentials.  

PubMed

A "picture book" of surface potentials, Laplacians, and magnetic fields due to distributed, neocortical sources is presented. The mathematically simulated data is based on 4200 current sources at the macrocolumn scale. Estimated scalp surface maps are based on the three-concentic spheres model of the head. Emphasis is placed on the effects of sampling with a limited number of electrodes, the choice of reference electrode, and the use of the spline Laplacian to improve spatial resolution. The spline Laplacian is applied to median and ulnar nerve somatosensory evoked potentials and to auditory evoked potentials including P300. Substantial improvement in spatial resolution over conventional methods is obtained. The implementation of practical high resolution EEG systems based on the spline Laplacian is considered. PMID:1793689

Nunez, P L; Pilgreen, K L; Westdorp, A F; Law, S K; Nelson, A V

1991-01-01

221

Effects of luminance on dynamic random-dot correlogram evoked visual potentials.  

PubMed

Although dynamic random-dot correlogram evoked visual potentials (DRDC-VEPs) are a three-decade-old method to detect the cortical binocularity in humans and animals, our knowledge of the influence of fundamental stimulus parameters and the underlying cerebral processing mechanisms has remained limited. The purpose of this study was to evaluate the effect of luminance on DRDC-VEPs in adults. The variability and detectability of DRDC-VEPs were investigated under different stimulus luminance conditions with neutral density filters. Our results have demonstrated that DRDC-VEPs can be evoked in a wide luminance range, and the response amplitude was practically independent of luminance between 4.75 cd m(-2) and 0.015 cd m(-2), while DRDC-VEP latencies showed a strong linear correlation with log luminance. There is, however, a limit (0.06 cd m(-2)) below which DRDC-VEPs are not reliably recordable. Luminance reduction-induced delays in DRDC-VEP latencies cannot be explained simply by retinal mechanisms, since their regression slope does not follow the course of electroretinogram and cortical evoked potential latencies. Luminance independence of DRDC-VEP amplitude suggests that binocular correlation-processing cortical neurons receive input predominantly from the magnocellular visual pathway. PMID:23094455

Markó, Katalin; Mikó-Baráth, Eszter; Kiss, Huba J; Török, Béla; Jandó, Gábor

2012-01-01

222

Temperature effects on evoked potentials of hippocampal slices from euthermic chipmunks, hamsters and rats  

NASA Technical Reports Server (NTRS)

1. Neural activity was recorded in hippocampal slices from euthermic chipmunks, hamsters and rats. 2. While recording the evoked potentials, the temperature of the Ringer's solution bathing the slice was varied by controlling the temperature of an outer chamber jacketing the recording chamber. 3. The temperature just below that at which a population spike could be evoked, Tt, was 10.4 +/- 0.3 degrees C (mean +/- SEM) for chipmunk slices, 14.1 +/- 0.4 degrees C for rat slices and 14.8 +/- 0.4 degrees C for hamster slices. Tt was significantly lower in the chipmunk slices (P<0.01) than in the rat and hamster slices. 4. Data were interpreted as consistent with the hypothesis that chipmunk hippocampal neurons are intrinsically cold resistant.

Hooper, D. C.; Martin, S. M.; Horowitz, J. M.

1985-01-01

223

Motor evoked potentials from the pelvic floor in patients with multiple sclerosis.  

PubMed

The use of motor evoked potentials (MEPs) to study the integrity of pelvic floor motor innervation is poorly described in the literature. This study evaluated the clinical use of pelvic floor MEPs in 16 women with multiple sclerosis. Lower urinary tract dysfunction was assessed with urodynamic investigations. Transcutaneous magnetic stimulation was applied over the motor cortex and spinal roots, and MEPs were recorded from the puborectalis, the external urethral sphincter, and the abductor hallucis muscles. In many patients, responses from the pelvic floor muscles could not be evoked, and central motor conduction times for the puborectalis motor pathways could only be calculated in 56%. There was a poor correlation of abnormal conduction to lower urinary tract dysfunction. It is concluded, that unevokable responses from pelvic floor muscles in a patient with multiple sclerosis should be interpreted with care, and that pelvic floor MEPs have a limited clinical value in the investigation of suspected demyelinating disease. PMID:12640072

Brostrom, S; Frederiksen, J L; Jennum, P; Lose, G

2003-04-01

224

Stimulus novelty, task relevance and the visual evoked potential in man  

NASA Technical Reports Server (NTRS)

The visual evoked potential (VEP) to rare, task-relevant (counted) numerical stimuli was compared with VEPs to rare, task-irrelevant stimuli, both being randomly interspersed within a sequence of tachistoscopically-flashed background numbers. These task-irrelevant stimuli were of two classes: (1) easily recognizable (e.g., simple geometric shapes) and (2) completely novel (i.e., complex, colorful abstract-type drawings which were unrecognizable). It was found that such novel stimuli did, in fact, evoke large P3 waves, but they had different scalp distributions from those which followed the task-relevant stimuli. This indicates that at least two types of late positive P3 waves exist, differing both in brain source and psychological correlates.

Courchesne, E.; Hillyard, S. A.; Galambos, R.

1975-01-01

225

Mechanically evoked cerebral potentials to sudden ankle dorsiflexion in human subjects during standing.  

PubMed

Mechanically evoked cerebral potentials (MECP) were studied in humans standing on a movable platform with three different stance widths. A sudden platform tilt of 4 degrees produced ankle dorsiflexion and resulted in scalp potentials of five distinct components, the earliest being a positive deflection at 35/60 ms. Their latencies have shown fairly consistent values among the three stance widths, while the amplitudes underwent some significant changes under the wide stance condition as compared with tightly close feet. These findings were interpreted as purporting evidence of altered somaesthetic afferent input from lower limbs during standing with widely apart support surface. PMID:8733304

Dimitrov, B; Gavrilenko, T; Gatev, P

1996-04-26

226

[Exploration of the auditory system in humans: From click to speech auditory brainstem responses].  

PubMed

There is a growing and unprecedented interest in the objective evaluation of the subcortical processes that are involved in speech perception, with potential clinical applications in speech and language impairments. Here, we review the studies illustrating the development of electrophysiological methods for assessing speech encoding in the human brainstem: from the pioneer recordings of click-evoked auditory brainstem responses (ABR), via studies of frequency-following responses (FFR) to the most recent measurements of speech ABR (SABR) or ABR in response to speech sounds. Recent research on SABR has provided new insights in the understanding of subcortical auditory processing mechanisms. The SABR test is an objective and non-invasive tool for assessing individual capacity of speech encoding in the brainstem. SABR characteristics are potentially useful both as a diagnosis tool of speech encoding deficits and as an assessment tool of the efficacy of rehabilitation programs in patients with learning and/or auditory processing disorders. PMID:21093798

Richard, C; Jeanvoine, A; Veuillet, E; Moulin, A; Thai-Van, H

2010-01-01

227

Long-term changes in entorhinal-dentate evoked potentials induced by electroconvulsive shock seizures in rats  

Microsoft Academic Search

Entorhinal-dentate evoked potentials were measured in rats before and after: (1) eight electroconvulsive shock (ECS) seizures, or (2) matched handling. In animals that received ECS, evoked potentials were significantly enhanced, as evidenced by a long-lasting increase in the amplitude of the population spike. This increase in population-spike amplitude lasted for at least 3 months after the last ECS trial. No

W. McIntyre Burnham; Georgia A. Cottrell; David Diosy; Ronald J. Racine

1995-01-01

228

Neuronal current magnetic resonance imaging of evoked potentials and neural oscillations  

NASA Astrophysics Data System (ADS)

Despite its great success, the current functional magnetic resonance imaging (MRI) technique relies on changes in cerebral hemodynamic parameters to infer the underlying neural activities, and as a result is limited in its spatial and temporal resolutions. In this dissertation, we discuss the feasibility of neuronal current MRI (nc-MRI), a novel technique in which the small magnetic field changes caused by neuronal electrical activities are directly measured by MRI. Two studies are described. In the first study, we investigated the feasibility of detecting the magnetic field produced by sensory evoked potentials. To eliminate the blood-oxygen-level-dependent (BOLD) effect on the MRI signal, which confounded most previous studies, an octopus visual system model was developed, which, for the first time, allowed for an in vivo investigation of nc-MRI in a BOLD-free environment. Electrophysiological responses were measured in the octopus retina and optical lobe to guide the nc-MRI acquisition. Our results indicated that no nc-MRI signal change related to neuronal activation could be detected at 0.2°/0.2% threshold for signal phase/magnitude respectively, while robust electrophysiological responses were recorded. In the second study, we discuss the feasibility of detecting neural oscillations with MRI, Based on previous studies, a novel approach was proposed in which an external oscillatory field was exploited as the excitation pulse under a spin-locked condition. This approach has the advantages of increased sensitivity and lowered physiological noise. Successful detection of sub-nanotesla field was demonstrated in phantom. Our results suggest that evoked potentials are too weak for nc-MRI detection with the current hardware, and that previous positive findings were likely due to hemodynamic confounders. On the other hand, oscillatory magnetic field can be efficiently detected in phantom. Given the stronger equivalent current dipoles produced by neural oscillations compared to evoked potentials, they might be a more promising candidate for future nc-MRI studies.

Jiang, Xia

229

The Investigation of Cortical Auditory Evoked Potentials Responses in Young Adults Having Musical Education  

PubMed Central

Background: In the literature, music education has been shown to enhance auditory perception for children and young adults. When compared to young adult non-musicians, young adult musicians demonstrate increased auditory processing, and enhanced sensitivity to acoustic changes. The evoked response potentials associated with the interpretation of sound are enhanced in musicians. Studies show that training also changes sound perception and cortical responses. The earlier training appears to lead to larger changes in the auditory cortex. Aims: Most cortical studies in the literature have used pure tones or musical instrument sounds as stimuli signals. The aim of those studies was to investigate whether musical education would enhance auditory cortical responses when speech signals were used. In this study, the speech sounds extracted from running speech were used as sound stimuli. Study Design: Non-randomized controlled study. Methods: The experimental group consists of young adults up to 21 years-old, all with a minimum of 4 years of musical education. The control group was selected from young adults of the same age without any musical education. The experiments were conducted by using a cortical evoked potential analyser and /m/, /t/ /g/ sound stimulation at the level of 65 dB SPL. In this study, P1 / N1 / P2 amplitude and latency values were measured. Results: Significant differences were found in the amplitude values of P1 and P2 (p<0.05). The differences among the latencies were not found to be significantly important (p>0.05). Conclusion: The results obtained in our study indicate that musical experience has an effect on the nervous system and this can be seen in cortical auditory evoked potentials recorded when the subjects hear speech.

Polat, Zahra; Ata?, Ahmet

2014-01-01

230

Differentiation between cortical and subcortical lesions following focal ischemia in cats by multimodality evoked potentials.  

PubMed

Regional ischemia was induced in cats by occluding the middle cerebral artery. Evoked and spontaneous electrical activity as well as regional cerebral blood flow (rCBF) were recorded with platinum depth macroelectrodes in three primary cortical areas: the auditory cortex (A, middle ectosylvian gyrus) and the front and hind limb somatosensory cortex (SF and SH, lateral and medial posterior sigmoid gyrus). To distinguish among the various evoked potentials after click, median or tibial nerve stimulation, electrical field interactions had to be eliminated using a multiplex stimulation and analysis system. Spontaneous electrocortical activity was evaluated by power spectral analysis. In all areas, evoked potentials were abolished 10 min after arterial occlusion. However, rCBF behaved differently in these regions: it was severely reduced in A, decreased moderately in SF and remained unchanged in SH. The graded reduction of rCBF in the three cortical areas was related to changes in electrophysiological activity during the first minutes of ischemia. In A, auditory potentials were abolished within 3 min after occlusion, whereas in SH, the decrease of somatosensory responses started after about 5 min. In SF, two components of the EP changes were found: an early decrease immediately and a later decrease about 5 min after occlusion. The different rates of EP impairment possibly correspond to two types of ischemia. The fast EP abolishment seems to be caused by local cortical damage whereas the delayed EP decrease probably reflects impairment of subcortical white matter structures. Thus, this method may be useful for distinguishing between gray and white matter ischemia. PMID:3612168

Kataoka, K; Graf, R; Rosner, G; Radermacher, B; Heiss, W D

1987-06-01

231

Middle ear muscle contractions and their relation to pulse and echo evoked potentials in the bat  

NASA Technical Reports Server (NTRS)

An analysis is made of pulse and echo orientation cries of the Mustache Bat. That bat's cries are characterized by a long, 60 to 30 msec, pure tone component and brief beginning and terminal FM sweeps. In addition to obvious echo overlap and middle ear muscle contractions, the following are examined: (1) characteristics of pulse- and echo-evoked potential under various conditions, (2) evidence of changes in hearing sensitivity during and after pulse emission, and (3) the role of the middle ear muscles in bringing about these changes.

Henson, O. W., Jr.; Henson, M. M.

1972-01-01

232

Quantitative parameters of facial motor evoked potential during vestibular schwannoma surgery predict postoperative facial nerve function  

Microsoft Academic Search

Background  Facial motor evoked potential (FMEP) amplitude ratio reduction at the end of the surgery has been identified as a good predictor\\u000a for postoperative facial nerve outcome. We sought to investigate variations in FMEP amplitude and waveform morphology during\\u000a vestibular schwannoma (VS) resection and to correlate these measures with postoperative facial function immediately after\\u000a surgery and at the last follow-up.\\u000a \\u000a \\u000a \\u000a \\u000a Methods  Intraoperative

Marcus André Acioly; Alireza Gharabaghi; Marina Liebsch; Carlos Henrique Carvalho; Paulo Henrique Aguiar; Marcos Tatagiba

2011-01-01

233

Emotional Body-Word Conflict Evokes Enhanced N450 and Slow Potential  

PubMed Central

Emotional conflict refers to the influence of task irrelevant affective stimuli on current task set. Previously used emotional face-word tasks have produced certain electrophysiological phenomena, such as an enhanced N450 and slow potential; however, it remains unknown whether these effects emerge in other tasks. The present study used an emotional body-word conflict task to investigate the neural dynamics of emotional conflict as reflected by response time, accuracy, and event-related potentials, which were recorded with the aim of replicating the previously observed N450 and slow potential effect. Results indicated increased response time and decreased accuracy in the incongruent condition relative to the congruent condition, indicating a robust interference effect. Furthermore, the incongruent condition evoked pronounced N450 amplitudes and a more positive slow potential, which might be associated with conflict-monitoring and conflict resolution. The present findings extend our understanding of emotional conflict to the body-word domain. PMID:24819150

Ma, Jianling; Liu, Chang; Zhong, Xin; Wang, Lu; Chen, Xu

2014-01-01

234

Control of humanoid robot via motion-onset visual evoked potentials  

PubMed Central

This paper investigates controlling humanoid robot behavior via motion-onset specific N200 potentials. In this study, N200 potentials are induced by moving a blue bar through robot images intuitively representing robot behaviors to be controlled with mind. We present the individual impact of each subject on N200 potentials and discuss how to deal with individuality to obtain a high accuracy. The study results document the off-line average accuracy of 93% for hitting targets across over five subjects, so we use this major component of the motion-onset visual evoked potential (mVEP) to code people's mental activities and to perform two types of on-line operation tasks: navigating a humanoid robot in an office environment with an obstacle and picking-up an object. We discuss the factors that affect the on-line control success rate and the total time for completing an on-line operation task. PMID:25620918

Li, Wei; Li, Mengfan; Zhao, Jing

2015-01-01

235

Evoked-potential audiogram of an Indo-Pacific humpback dolphin (Sousa chinensis).  

PubMed

An evoked-potential audiogram was measured for an Indo-Pacific humpback dolphin (Sousa chinensis) living in the dolphinarium of Nanning Zoo, China. Rhythmic 20 ms pip trains composed of cosine-enveloped 0.25 ms tone pips at a pip rate of 1 kHz were presented as sound stimuli. The dolphin was trained to remain still at the water surface and to wear soft latex suction-cup EEG electrodes used to measure the animal's envelope-following evoked potentials to the sound stimuli. Responses to 1000 rhythmic 20 ms pip trains for each amplitude/frequency combination were averaged and analysed using a fast Fourier transform to obtain an evoked auditory response. The hearing threshold was defined as the zero crossing point of the response input-output function using linear regression. Fourteen frequencies ranging from 5.6 to 152 kHz were studied. The results showed that most of the thresholds were lower than 90 dB re. 1 ?Pa (r.m.s.), covering a frequency range from 11.2 to 128 kHz, and the lowest threshold of 47 dB was measured at 45 kHz. The audiogram, which is a function of hearing threshold versus stimulus carrier frequency, presented a U-shape with a region of high hearing sensitivity (within 20 dB of the lowest threshold) between approximately 20 and 120 kHz. At frequencies lower than this high-sensitivity region, thresholds increased at a rate of approximately 11 dB octave(-1) up to 93 dB at 5.6 kHz. The thresholds at high frequencies above 108 kHz increased steeply at a rate of 130 dB octave(-1) up to 127 dB at 152 kHz. PMID:22660775

Li, Songhai; Wang, Ding; Wang, Kexiong; Taylor, Elizabeth A; Cros, Emilie; Shi, Wenjing; Wang, Zhitao; Fang, Liang; Chen, Yuefei; Kong, Fanming

2012-09-01

236

Lateral Geniculate Body Evoked Potentials Elicited by Visual and Electrical Stimulation  

PubMed Central

Purpose Blind individuals who have photoreceptor loss are known to perceive phosphenes with electrical stimulation of their remaining retinal ganglion cells. We proposed that implantable lateral geniculate body (LGB) stimulus electrode arrays could be used to generate phosphene vision. We attempted to refine the basic reference of the electrical evoked potentials (EEPs) elicited by microelectrical stimulations of the optic nerve, optic tract and LGB of a domestic pig, and then compared it to visual evoked potentials (VEPs) elicited by short-flash stimuli. Methods For visual function measurement, VEPs in response to short-flash stimuli on the left eye of the domestic pig were assessed over the visual cortex at position Oz with the reference electrode at Fz. After anesthesia, linearly configured platinum wire electrodes were inserted into the optic nerve, optic track and LGB. To determine the optimal stimulus current, EEPs were recorded repeatedly with controlling the pulse and power. The threshold of current and charge density to elicit EEPs at 0.3 ms pulse duration was about ±10 µA. Results Our experimental results showed that visual cortex activity can be effectively evoked by stimulation of the optic nerve, optic tract and LGB using penetrating electrodes. The latency of P1 was more shortened as the electrical stimulation was closer to LGB. The EEPs of two-channel in the visual cortex demonstrated a similar pattern with stimulation of different spots of the stimulating electrodes. We found that the LGB-stimulated EEP pattern was very similar to the simultaneously generated VEP on the control side, although implicit time deferred. Conclusions EEPs and VEPs derived from visual-system stimulation were compared. The LGB-stimulated EEP wave demonstrated a similar pattern to the VEP waveform except implicit time, indicating prosthetic-based electrical stimulation of the LGB could be utilized for the blind to perceive vision of phosphenes. PMID:25120343

Choi, Chang Wook; Kim, Pan Sang; Shin, Sun Ae; Yang, Ji Yeon

2014-01-01

237

Deficient brainstem encoding of pitch in children with Autism Spectrum Disorders q  

E-print Network

Deficient brainstem encoding of pitch in children with Autism Spectrum Disorders q N.M. Russoa evoked brainstem responses to speech syllables with descending and ascending pitch contours, we examined of Clinical Neurophysiology. Keywords: Auditory brainstem; Autism; Pitch tracking; Prosody 1. Introduction

238

Research paper Relationships between behavior, brainstem and cortical encoding of seen and  

E-print Network

Research paper Relationships between behavior, brainstem and cortical encoding of seen and heard brainstem structures are enhanced in musi- cians, compared to non-musicians. Specifically, musicians have levels? To answer this question, we recorded simultaneous brainstem and cortical evoked responses

239

Functional and topographical properties of field potentials evoked in rat dorsal horn by cutaneous C-fibre stimulation.  

PubMed Central

Extracellular field potentials in the lumbosacral dorsal horn evoked by stimulation of cutaneous C fibres in the sural nerve were explored in the halothane-anaesthetized rat. C-fibre-evoked field potentials were prominent in lamina II and lamina V of the dorsal horn. These potentials had a latency of 80-130 ms and a duration of more than 200 ms. A peak in the C-fibre-evoked field potential, termed the CI potential, with a median latency of 120 ms, range 105-150 ms, was distinguished in lamina II. The time from onset to peak of the CI potential was, on average, 13 ms when all C fibres were activated. The amplitude of the CI potential in lamina II was directly proportional to the amplitude of the C-fibre-evoked nerve volley, whereas the relation between the C-fibre nerve volley and the C-fibre-evoked field potential in lamina V was non-linear. A selective block of A fibres did not influence the amplitude of these field potentials. Following stimulation of C afferent fibres in the medial sural nerve, at frequencies higher than 0.1 Hz, the CI potential in lamina II, but not the C-fibre-evoked field potential in lamina V, was increased. There was no concomitant change of the A-fibre-evoked field potentials. The magnitude of the potentiation of the CI potential was dependent both on the frequency and the number of stimuli. Mean percentage potentiation was 200%, range 150-300%, after seventy stimulations at a frequency of 1.0 Hz. During the stimulation the CI potential increased monotonically. The decay of the potentiation of the CI potential was well described by two exponentially declining phases. There was a positive correlation between the size of the time constants of the decay and the number of stimuli during conditioning. Following noxious radiant heat (temperature 50-55 degrees C) applied to a restricted part of the skin (area 20-30 mm2) within the receptive field of the medial sural nerve for 10-20 s, the CI potential was potentiated by 50-130%. The duration of this potentiation was 3-15 min. This potentiation was somatotopically organized. By contrast, there was no effect on the amplitude of the CI potential following innocuous skin stimulation (slowly moving contact, brushing the skin, warmth 40 degrees C).(ABSTRACT TRUNCATED AT 400 WORDS) PMID:6520786

Schouenborg, J

1984-01-01

240

AIDED CORTICAL AUDITORY EVOKED POTENTIALS IN RESPONSE TO CHANGES IN HEARING AID GAIN  

PubMed Central

OBJECTIVE There is interest in using cortical auditory evoked potentials (CAEPs) to evaluate hearing aid fittings and experience-related plasticity associated with amplification; however, little is known about hearing aid signal processing effects on these responses. The purpose of this study was to determine the effect of clinically relevant hearing aid gain settings, and the resulting in-the-canal signal-to-noise ratios (SNRs), on the latency and amplitude of P1, N1, and P2 waves. DESIGN & SAMPLE Evoked potentials and in-the-canal acoustic measures were recorded in nine normal-hearing adults in unaided and aided conditions. In the aided condition, a 40-dB signal was delivered to a hearing aid programmed to provide four levels of gain (0, 10, 20, and 30 dB). As a control, unaided stimulus levels were matched to aided condition outputs (i.e., 40, 50, 60, and 70 dB) for comparison purposes. RESULTS When signal levels are defined in terms of output level, aided CAEPs were surprisingly smaller and delayed relative to unaided CAEPs, likely resulting from increases to noise levels caused by the hearing aid. DISCUSSION These results reinforce the notion that hearing aids modify stimulus characteristics such as SNR, which in turn affects the CAEP in a way that does not reliably reflect hearing aid gain. PMID:21486122

Billings, Curtis J.; Tremblay, Kelly L.; Miller, Christi W.

2011-01-01

241

Effect of Test Duration on the Visual-Evoked Potential (VEP) and Alpha Wave Responses  

PubMed Central

Primary objective The purpose of this study was to assess the effect of test duration on the visual-evoked potential (VEP) and related alpha power spectrum measures. Design and methods Two conditions (eyes-closed and eyes-open) were tested using four different durations: ten, twenty, forty-five, and sixty seconds. The Diopsys™ NOVA-TR system was used to obtain the visual-evoked potential (VEP) and extracted alpha-wave with its related power spectrum. 16 visually-normal, young-adult subjects (ages 22 to 25 years) participated in the experiment. The stimulus for the eyes-open condition consisted of a black-and-white, alternating checkerboard pattern with a small central fixation target. All trials were performed during one session. Results Regarding the VEP parameters, only variability of the VEP amplitude changed significantly with test duration: it decreased with increasing test duration, with the 45 and 60 second trials showing similarly low variability. Regarding the alpha wave parameters, test duration did not have a significant effect on either the mean alpha power or its variability across trials. Conclusions The findings demonstrate that forty-five second test durations are sufficient to minimize intra-session variability of the VEP amplitude and latency measurements, whereas several 10 second test durations may be sufficient for accurate measurement of the alpha wave. Optimization of test duration allows for repeatable measures with less total test time. This is especially important for special clinical populations. PMID:23203780

Willeford, Kevin T.; Ciuffreda, Kenneth J.; Yadav, Naveen K.

2014-01-01

242

Diminished N1 Auditory Evoked Potentials to Oddball Stimuli in Misophonia Patients  

PubMed Central

Misophonia (hatred of sound) is a newly defined psychiatric condition in which ordinary human sounds, such as breathing and eating, trigger impulsive aggression. In the current study, we investigated if a dysfunction in the brain’s early auditory processing system could be present in misophonia. We screened 20 patients with misophonia with the diagnostic criteria for misophonia, and 14 matched healthy controls without misophonia, and investigated any potential deficits in auditory processing of misophonia patients using auditory event-related potentials (ERPs) during an oddball task. Subjects watched a neutral silent movie while being presented a regular frequency of beep sounds in which oddball tones of 250 and 4000?Hz were randomly embedded in a stream of repeated 1000?Hz standard tones. We examined the P1, N1, and P2 components locked to the onset of the tones. For misophonia patients, the N1 peak evoked by the oddball tones had smaller mean peak amplitude than the control group. However, no significant differences were found in P1 and P2 components evoked by the oddball tones. There were no significant differences between the misophonia patients and their controls in any of the ERP components to the standard tones. The diminished N1 component to oddball tones in misophonia patients suggests an underlying neurobiological deficit in misophonia patients. This reduction might reflect a basic impairment in auditory processing in misophonia patients. PMID:24782731

Schröder, Arjan; van Diepen, Rosanne; Mazaheri, Ali; Petropoulos-Petalas, Diamantis; Soto de Amesti, Vicente; Vulink, Nienke; Denys, Damiaan

2014-01-01

243

Diminished n1 auditory evoked potentials to oddball stimuli in misophonia patients.  

PubMed

Misophonia (hatred of sound) is a newly defined psychiatric condition in which ordinary human sounds, such as breathing and eating, trigger impulsive aggression. In the current study, we investigated if a dysfunction in the brain's early auditory processing system could be present in misophonia. We screened 20 patients with misophonia with the diagnostic criteria for misophonia, and 14 matched healthy controls without misophonia, and investigated any potential deficits in auditory processing of misophonia patients using auditory event-related potentials (ERPs) during an oddball task. Subjects watched a neutral silent movie while being presented a regular frequency of beep sounds in which oddball tones of 250 and 4000?Hz were randomly embedded in a stream of repeated 1000?Hz standard tones. We examined the P1, N1, and P2 components locked to the onset of the tones. For misophonia patients, the N1 peak evoked by the oddball tones had smaller mean peak amplitude than the control group. However, no significant differences were found in P1 and P2 components evoked by the oddball tones. There were no significant differences between the misophonia patients and their controls in any of the ERP components to the standard tones. The diminished N1 component to oddball tones in misophonia patients suggests an underlying neurobiological deficit in misophonia patients. This reduction might reflect a basic impairment in auditory processing in misophonia patients. PMID:24782731

Schröder, Arjan; van Diepen, Rosanne; Mazaheri, Ali; Petropoulos-Petalas, Diamantis; Soto de Amesti, Vicente; Vulink, Nienke; Denys, Damiaan

2014-01-01

244

Loudness dependence of auditory evoked potentials in patients with borderline personality disorder--impact of psychopathology.  

PubMed

Alterations of the central serotonergic system are considered to be involved in the pathophysiology of borderline personality disorder (BPD). The loudness dependence of the N1/P2 component of auditory evoked potentials (LD) has been shown to indirectly reflect central serotonergic activity. The aim of this study was to investigate LD in patients with BPD compared to healthy controls, and to evaluate the association between LD and psychopathology such as anxiety, anger or impulsiveness. Female patients with BPD were included and compared to age- and sex-matched healthy subjects. Self-rating instruments, such as the State-Trait Anxiety Inventory (STAI), State-Trait Anger Expression Inventory (STAXI), and the Barratt Impulsiveness Scale (BIS) were used to assess clinical scores of anxiety, anger, and impulsiveness. Evoked potentials were recorded following the application of acoustic stimuli with increasing intensities; the LD was analysed using dipole source analysis. The mean LD was significantly higher in patients with BPD compared to controls. In the entire sample there were significant positive correlations of LD with state anxiety scores and STAXI subscores. The data contribute to the knowledge of neurophysiological alterations in patients with BPD, supporting the hypothesis of serotonergic dysregulation in the pathophysiology of the disorder. The significant clinical correlations suggest monoaminergic modulations of psychopathology on the symptom level. PMID:22542953

Schaaff, Nadine; Karch, Susanne; Segmiller, Felix; Koch, Walter; Reicherzer, Markus; Mulert, Christoph; Hegerl, Ulrich; Juckel, Georg; Pogarell, Oliver

2012-10-30

245

Pericellular Ca2+ recycling potentiates thrombin-evoked Ca2+ signals in human platelets  

PubMed Central

We have previously demonstrated that Na+/Ca2+ exchangers (NCXs) potentiate Ca2+ signaling evoked by thapsigargin in human platelets, via their ability to modulate the secretion of autocoids from dense granules. This link was confirmed in platelets stimulated with the physiological agonist, thrombin, and experiments were performed to examine how Ca2+ removal by the NCX modulates platelet dense granule secretion. In cells loaded with the near-membrane indicator FFP-18, thrombin stimulation was observed to elicit an NCX-dependent accumulation of Ca2+ in a pericellular region around the platelets. To test whether this pericellular Ca2+ accumulation might be responsible for the influence of NCXs over platelet function, platelets were exposed to fast Ca2+ chelators or had their glycocalyx removed. Both manipulations of the pericellular Ca2+ rise reduced thrombin-evoked Ca2+ signals and dense granule secretion. Blocking Ca2+-permeable ion channels had a similar effect, suggesting that Ca2+ exported into the pericellular region is able to recycle back into the platelet cytosol. Single cell imaging with extracellular Fluo-4 indicated that thrombin-evoked rises in extracellular [Ca2+] occurred within the boundary described by the cell surface, suggesting their presence within the open canalicular system (OCS). FFP-18 fluorescence was similarly distributed. These data suggest that upon thrombin stimulation, NCX activity creates a rise in [Ca2+] within the pericellular region of the platelet from where it recycles back into the platelet cytosol, acting to both accelerate dense granule secretion and maintain the initial rise in cytosolic [Ca2+]. PMID:24303163

Sage, Stewart O; Pugh, Nicholas; Farndale, Richard W; Harper, Alan G S

2013-01-01

246

Dendritic calcium transients evoked by single back-propagating action potentials in rat neocortical pyramidal neurons.  

PubMed Central

1. Dendrites of rat neocortical layer V pyramidal neurons were loaded with the Ca2+ indicator dye Calcium Green-1 (CG-1) or fluo-3, and the mechanisms which govern action potential (AP)-evoked transient changes in dendritic cytosolic Ca2+ concentration ([Ca2+]i) were examined. APs were initiated either by synaptic stimulation or by depolarizing the soma or dendrite by current injection, and changes in fluorescence of the indicator dye were measured in the proximal 170 microns of the apical dendrite. 2. Simultaneous two-pipette recordings of APs from the soma and apical dendrite, and dendritic fluorescence imaging indicated that a single AP propagating from the soma into the apical dendrite evokes a rapid transient increase in fluorescence indicating a transient increase in [Ca2+]i. At 35-37 degrees C the decay time constant of the fluorescence transient following an AP was around 80 ms. 3. Voltage-activated Ca2+ channels (VACCs) of several subtypes mediated the AP-evoked fluorescence transient in the proximal (100-170 microns) apical dendrite. The AP-evoked fluorescence transient resulted from Ca2+ entry through L-type (nifedipine sensitive; 25%), N-type (omega-conotoxin GVIA sensitive; 28%) and P-type (omega-agatoxin IVA sensitive; 10%) Ca2+ channels and through Ca2+ channels (R-type) not sensitive to L-, N- and P-type Ca2+ channel blockers (cadmium ion sensitive; 37%). 4. The decay time course of the dendritic fluorescence transient was prolonged by the blockers of endoplasmic reticulum (ER) Ca(2+)-ATPase, cyclopiazonic acid and thapsigargin, suggesting that uptake of Ca2+ into the ER in dendrites governs clearance of dendritic Ca2+. 5. The decay time course of the fluorescence transient was slightly prolonged by benzamil, a blocker of plasma membrane Na(+)-Ca2+ exchange and by calmidazolium, a blocker of the calmodulin-dependent plasma membrane Ca(2+)-ATPase, suggesting that these pathways are less important for dendrite Ca2+ clearance following a single AP. Neither the mitochondrial uncoupler carbonyl cyanide p-(trifluoromethoxy)phenylhydrazone (FCCP) nor the blocker of Ca2+ uptake into mitochondria, Ruthenium Red, had any measurable effect on the decay time course of the fluorescence transient. 6. Dendritic fluorescence transients measured during trains of dendritic APs began to summate at impulse frequencies of 5 APs s-1. At higher frequencies APs caused a concerted and maintained elevation of dendritic fluorescence during the train.(ABSTRACT TRUNCATED AT 400 WORDS) Images Figure 1 Figure 2 Figure 3 Figure 9 PMID:7658365

Markram, H; Helm, P J; Sakmann, B

1995-01-01

247

Post-tetanic mechanical tension and evoked action potentials in McArdle's disease  

PubMed Central

The tension produced by the cramp evoked in the adductor pollicis muscle by repetitive stimuli to the nerve (20/s for 50 s) and by full voluntary effort in the brachial biceps was measured in a patient with McArdle's disease. The contracture was 17% of the peaktetanic tension, and was not associated with action potentials. Twitches superimposed on the contracture were at most diminished to half, as were their action potentials. Both slow and fast muscle fibres participated in the contracture. The contraction time of the twitches elicited after the tetanus was prolonged more in the patient than in a normal subject of the same age. There was evidence of delayed firing, first observed 90 seconds after the peak of the contracture. The patient had electromyographic and histological signs of myopathy. PMID:271684

Brandt, N. J.; Buchthal, F.; Ebbesen, F.; Kamieniecka, Z.; Krarup, C.

1977-01-01

248

Extra-muscle involvement in dystrophinopathies: an electroretinography and evoked potential study.  

PubMed

Dystrophin is present in various tissues other than skeletal and cardiac muscles, including the central nervous system (CNS) and the outer plexiform layer of the retina. Therefore lack of dystrophin might be related to mental retardation or to changes in electrophysiological tests exploring retina and CNS. We performed electroretinography, VEPs, BAEPs, SEPs and MEPs in 18 patients with Duchenne muscular dystrophy (DMD), 18 with Becker muscular dystrophy (BMD) and 12 obligate carriers. We observed a marked reduction of the b-wave amplitude in the scotopic ERG, mainly in DMD patients. Oscillatory potentials were altered in all groups, even in carriers, suggesting that dystrophin may be also involved in retinal circulation. VEPs changes confirmed the role of dystrophin in visual function. The other evoked potentials were altered only in a small percentage of subjects but changes of different tests did not overlap in individual subjects. Neurophysiological abnormalities did not correlate with type, site and size of alteration in the dystrophin gene. PMID:9077508

Girlanda, P; Quartarone, A; Buceti, R; Sinicropi, S; Macaione, V; Saad, F A; Messina, L; Danieli, G A; Ferreri, G; Vita, G

1997-03-10

249

Human cerebral potentials evoked by CO2 laser stimuli causing pain.  

PubMed

Brief radiant heat pulses, generated by a CO2 laser, were used to activate slowly conducting afferents in the hairy skin in man. In order to isolate C-fibre responses a preferential A-fibre block was applied by pressure to the radial nerve at the wrist. Stimulus estimation and evoked cerebral potentials (EP), as well as reaction times, motor and sudomotor activity were recorded in response to each stimulus. With intact nerve, the single supra-threshold stimulus induced a double pain sensation: A first sharp and stinging component (mean reaction time 480 ms) was followed by a second burning component lasting for seconds (mean reaction time 1350 ms). Under A-fibre block only one sensation remained with characteristics and latencies of second pain. The heat pulse evoked potential consisted of a late vertex negativity at 240 ms (N240) followed by a prominent late positive peak at 370 ms (P370). Later activity was not reliably present. Under A-fibre block this late EP was replaced by an ultralate EP beyond 1000 ms, which in the conventional average looked like a slow halfwave of 800 ms duration. This potential was distinct from eye movements, skin potentials or muscle artefacts. With cross-correlation methods waveforms similar to the N240/P370 were detected in the latency range from 900 to 1500 ms during A-fibre block, indicating a much greater latency jitter of the ultralate EP. Latency corrected averaging with a modified Woody filter yielded a grand mean ultralate EP (N1050/P1250), the shape of which was surprisingly similar to the late EP (N240/P370). The similarity of these components indicates that both EPs may be secondary responses to afferent input into neural centers, onto which myelinated and unmyelinated fibres converge. Such convergence may also explain through the known mechanisms of short term habituation and selective attention, why ultralate EPs are not reliably present without peripheral nerve block. PMID:3622675

Bromm, B; Treede, R D

1987-01-01

250

The effects of rise/fall time and plateau time on ocular vestibular evoked myogenic potentials.  

PubMed

Ocular vestibular evoked myogenic potentials (oVEMP) are strongly influenced by recording conditions and stimulus parameters. Throughout the published literature, a large variety of stimuli is used for eliciting oVEMP. Our objective was to determine the effects of different rise/fall times and plateau times on oVEMP amplitudes and latencies. 32 healthy subjects were enrolled in the study. 500 Hz air-conducted tone bursts with the parameters rise-plateau-fall time 0-4-0, 4-0-4, 2-2-2 and 2-4-2 ms were used for eliciting oVEMP. For all stimuli, response prevalences were 100 %. The 4-0-4 ms stimulus generated the smallest amplitudes, whereas the 2-2-2 and 0-4-0 ms stimuli achieved the largest amplitudes. n1 and p1 latencies were significantly shorter for the 0-4-0 ms than for the other stimuli, whereas latencies in response to the 4-0-4 ms stimulus were prolonged. Hence, a variety of stimuli is suitable for evoking oVEMP in healthy subjects. We recommend a 2-2-2 ms stimulus for clinical testing of oVEMP elicited by air conducted sound, because it reproducibly generates oVEMP without exposing the ear to unnecessary amounts of acoustic energy. PMID:24096809

Kantner, Claudia; Hapfelmeier, Alexander; Drexl, Markus; Gürkov, Robert

2014-09-01

251

Comparison of visually evoked local field potentials in isolated turtle brain: patterned versus blank stimulation.  

PubMed

Isolated turtle brain/eye preparation has recently been used as a bloodless animal model for detecting the magnetic resonance imaging (MRI) signal changes produced by visually evoked neuronal currents. The present work aims to determine whether checkerboard-patterned or full field flash (blank) stimulation should be used in order to achieve stronger neuronal responses in turtle brain/eye preparation. The knowledge gained in this study is essential for optimizing the visual stimulation methods in functional neuroimaging studies using turtle brain/eye preparation. In this study, visually evoked local field potentials (LFPs) were measured and compared in turtle visual cortex and optic tectum elicited by checkerboard and full field flash stimuli with three different inter-stimulus intervals (ISIs=5, 10, and 16s). It was found that the behavior of neuronal adaptation in the cortical and tectal LFP signals for checkerboard stimulation was comparable to flash stimulation. In addition, there was no significant difference in the LFP peak amplitudes (ISI=16s) between these two stimuli. These results indicate that the intensity of neuronal responses to checkerboard is comparable to flash stimulation. These two stimulation methods should be equivalent in functional neuroimaging studies using turtle brain/eye preparation. PMID:20034520

Luo, Qingfei; Lu, Huo; Lu, Hanbing; Yang, Yihong; Gao, Jia-Hong

2010-03-15

252

Neuromodulation of motor-evoked potentials during stepping in spinal rats  

PubMed Central

The rat spinal cord isolated from supraspinal control via a complete low- to midthoracic spinal cord transection produces locomotor-like patterns in the hindlimbs when facilitated pharmacologically and/or by epidural electrical stimulation. To evaluate the role of epidural electrical stimulation in enabling motor control (eEmc) for locomotion and posture, we recorded potentials evoked by epidural spinal cord stimulation in selected hindlimb muscles during stepping and standing in adult spinal rats. We hypothesized that the temporal details of the phase-dependent modulation of these evoked potentials in selected hindlimb muscles while performing a motor task in the unanesthetized state would be predictive of the potential of the spinal circuitries to generate stepping. To test this hypothesis, we characterized soleus and tibialis anterior (TA) muscle responses as middle response (MR; 4–6 ms) or late responses (LRs; >7 ms) during stepping with eEmc. We then compared these responses to the stepping parameters with and without a serotoninergic agonist (quipazine) or a glycinergic blocker (strychnine). Quipazine inhibited the MRs induced by eEmc during nonweight-bearing standing but facilitated locomotion and increased the amplitude and number of LRs induced by eEmc during stepping. Strychnine facilitated stepping and reorganized the LRs pattern in the soleus. The LRs in the TA remained relatively stable at varying loads and speeds during locomotion, whereas the LRs in the soleus were strongly modulated by both of these variables. These data suggest that LRs facilitated electrically and/or pharmacologically are not time-locked to the stimulation pulse but are highly correlated to the stepping patterns of spinal rats. PMID:23761695

Gad, Parag; Lavrov, Igor; Shah, Prithvi; Zhong, Hui; Roy, Roland R.; Gerasimenko, Yury

2013-01-01

253

Neuromodulation of motor-evoked potentials during stepping in spinal rats.  

PubMed

The rat spinal cord isolated from supraspinal control via a complete low- to midthoracic spinal cord transection produces locomotor-like patterns in the hindlimbs when facilitated pharmacologically and/or by epidural electrical stimulation. To evaluate the role of epidural electrical stimulation in enabling motor control (eEmc) for locomotion and posture, we recorded potentials evoked by epidural spinal cord stimulation in selected hindlimb muscles during stepping and standing in adult spinal rats. We hypothesized that the temporal details of the phase-dependent modulation of these evoked potentials in selected hindlimb muscles while performing a motor task in the unanesthetized state would be predictive of the potential of the spinal circuitries to generate stepping. To test this hypothesis, we characterized soleus and tibialis anterior (TA) muscle responses as middle response (MR; 4-6 ms) or late responses (LRs; >7 ms) during stepping with eEmc. We then compared these responses to the stepping parameters with and without a serotoninergic agonist (quipazine) or a glycinergic blocker (strychnine). Quipazine inhibited the MRs induced by eEmc during nonweight-bearing standing but facilitated locomotion and increased the amplitude and number of LRs induced by eEmc during stepping. Strychnine facilitated stepping and reorganized the LRs pattern in the soleus. The LRs in the TA remained relatively stable at varying loads and speeds during locomotion, whereas the LRs in the soleus were strongly modulated by both of these variables. These data suggest that LRs facilitated electrically and/or pharmacologically are not time-locked to the stimulation pulse but are highly correlated to the stepping patterns of spinal rats. PMID:23761695

Gad, Parag; Lavrov, Igor; Shah, Prithvi; Zhong, Hui; Roy, Roland R; Edgerton, V Reggie; Gerasimenko, Yury

2013-09-01

254

Low-frequency rTMS inhibitory effects in the primary motor cortex: Insights from TMS-evoked potentials.  

PubMed

The neuromodulatory effects of repetitive transcranial magnetic stimulation (rTMS) have been mostly investigated by peripheral motor-evoked potentials (MEPs). New TMS-compatible EEG systems allow a direct investigation of the stimulation effects through the analysis of TMS-evoked potentials (TEPs). We investigated the effects of 1-Hz rTMS over the primary motor cortex (M1) of 15 healthy volunteers on TEP evoked by single pulse TMS over the same area. A second experiment in which rTMS was delivered over the primary visual cortex (V1) of 15 healthy volunteers was conducted to examine the spatial specificity of the effects. Single-pulse TMS evoked four main components: P30, N45, P60 and N100. M1-rTMS resulted in a significant decrease of MEP amplitude and in a significant increase of P60 and N100 amplitude. There was no effect after V1-rTMS. 1-Hz rTMS appears to increase the amount of inhibition following a TMS pulse, as demonstrated by the higher N100 and P60, which are thought to originate from GABAb-mediated inhibitory post-synaptic potentials. Our results confirm the reliability of the TMS-evoked N100 as a marker of cortical inhibition and provide insight into the neuromodulatory effects of 1-Hz rTMS. The present finding could be of relevance for therapeutic and diagnostic purposes. PMID:24793831

Casula, Elias P; Tarantino, Vincenza; Basso, Demis; Arcara, Giorgio; Marino, Giuliana; Toffolo, Gianna Maria; Rothwell, John C; Bisiacchi, Patrizia S

2014-09-01

255

Coordinated plasticity in brainstem and auditory cortex contributes to enhanced categorical speech perception in  

E-print Network

Coordinated plasticity in brainstem and auditory cortex contributes to enhanced categorical speech-related potentials, brainstem frequency-following response, categorical speech perception, experience in brainstem and cortical structures, as well as improved acuity for behav- iorally relevant sounds including

Dasgupta, Dipankar

256

Optimal electrical stimulation modality for cortical esophageal evoked potentials: transmural or intraesophageal?  

PubMed

Esophageal electrical stimulation using short and a relatively small number of (200 micros, 0.2 Hz, n = 25) electrical pulses generates a characteristic and well defined cortical evoked potential response (EP). There are two methods of stimulation: either through intraesophageal electrodes or with transmural electrodes. The objective of this paper is to compare EP response, sensations and heart rate variability power spectra elicited by both stimulation modalities in healthy volunteers. Our results suggest that transmural stimulation is more accurately perceived and at lower intensities, produces more reproducible peaks of higher amplitude than during intraesophageal stimulation. During either mode of esophageal stimulation, power within the high-frequency component of the heart rate variability power spectrum is enhanced. PMID:15825875

Kamath, Markad V; Hollerbach, Stephan; Spaziani, Robert; Shine, Glenn; Upton, Adrian R M; Tougas, Gervais

2005-04-01

257

Addition of visual noise boosts evoked potential-based brain-computer interface  

PubMed Central

Although noise has a proven beneficial role in brain functions, there have not been any attempts on the dedication of stochastic resonance effect in neural engineering applications, especially in researches of brain-computer interfaces (BCIs). In our study, a steady-state motion visual evoked potential (SSMVEP)-based BCI with periodic visual stimulation plus moderate spatiotemporal noise can achieve better offline and online performance due to enhancement of periodic components in brain responses, which was accompanied by suppression of high harmonics. Offline results behaved with a bell-shaped resonance-like functionality and 7–36% online performance improvements can be achieved when identical visual noise was adopted for different stimulation frequencies. Using neural encoding modeling, these phenomena can be explained as noise-induced input-output synchronization in human sensory systems which commonly possess a low-pass property. Our work demonstrated that noise could boost BCIs in addressing human needs. PMID:24828128

Xie, Jun; Xu, Guanghua; Wang, Jing; Zhang, Sicong; Zhang, Feng; Li, Yeping; Han, Chengcheng; Li, Lili

2014-01-01

258

Effect of body and foot positions on the somatosensory evoked potentials.  

PubMed

Somatosensory evoked potentials in response to stimulation of the posterior tibial nerve at the ankle were recorded during sitting and standing with variable foot positions. During standing a decrease in the amplitude of the early positive component was observed. The deviation of the foot from a horizontal position was associated with an increase in the amplitude of the early negative component. The combined influence of body and foot positions showed a decrease in the amplitude of both early and late components. The standing position induced changes in more components than the varied foot positions. This suggests that maintenance of the standing posture is a more complex task than the maintenance of the foot position itself. PMID:2399802

Gavrilenko, T; Gatev, P; Popivanov, D; Gantchev, G N

1990-06-01

259

Targeting Pain-evoking Transient Receptor Potential Channels for the Treatment of Pain.  

PubMed

Chronic pain affects billions of lives globally and is a major public health problem in the United States. However, pain management is still a challenging task due to a lack of understanding of the fundamental mechanisms of pain. In the past decades transient receptor potential (TRP) channels have been identified as molecular sensors of tissue damage and inflammation. Activation/sensitization of TRP channels in peripheral nociceptors produces neurogenic inflammation and contributes to both somatic and visceral pain. Pharmacological and genetic studies have affirmed the role of TRP channels in multiple forms of inflammatory and neuropathic pain. Thus pain-evoking TRP channels emerge as promising therapeutic targets for a wide variety of pain and inflammatory conditions. PMID:24396340

Luo, Jialie; Walters, Edgar T; Carlton, Susan M; Hu, Hongzhen

2013-12-01

260

Targeting Pain-evoking Transient Receptor Potential Channels for the Treatment of Pain  

PubMed Central

Chronic pain affects billions of lives globally and is a major public health problem in the United States. However, pain management is still a challenging task due to a lack of understanding of the fundamental mechanisms of pain. In the past decades transient receptor potential (TRP) channels have been identified as molecular sensors of tissue damage and inflammation. Activation/sensitization of TRP channels in peripheral nociceptors produces neurogenic inflammation and contributes to both somatic and visceral pain. Pharmacological and genetic studies have affirmed the role of TRP channels in multiple forms of inflammatory and neuropathic pain. Thus pain-evoking TRP channels emerge as promising therapeutic targets for a wide variety of pain and inflammatory conditions PMID:24396340

Luo, Jialie; Walters, Edgar T.; Carlton, Susan M.; Hu, Hongzhen

2013-01-01

261

[Somatosensory evoked potentials before and after stereotaxic operations in patients with childhood cerebral palsy].  

PubMed

The somatosensory function in patients with the hyperkinetic form of infantile cerebral paralysis (ICP) was evaluated by means of short-latent somatosensory evoked potentials (SSEP) in the preoperative period and after stereotaxic operations on the thalamic nuclei and structures of the subthalamic region; the evaluation was conducted by comparison with the dynamics of the main manifestations of the disease. The SSEP characteristics in patients in the preoperative period bear evidence of bilateral disorders in the somatosensory system. Stereotaxic operations, leading to certain normalization of the muscular tone and inhibition of hyperkinesis, do not cause positive changes of the SSEP characteristics. The peculiarities of the SSEP characteristics in the preoperative period in patients with ICP may serve as a definite prognostic sign of the efficacy of stereotaxic operations in these patients. PMID:3064519

Tomas, D; Shabalov, V A

1988-01-01

262

Evoked potentials of the auditory cortex of the porpoise, Phocoena phocoena.  

PubMed

Evoked potential (EP) recordings in the auditory cortex of the porpoise, Phocoena phocoena, were used to obtain data characterizing the auditory perception of this dolphin. The frequency threshold curves showed that the lowest EP thresholds were within 120-130 kHz. An additional sensitivity peak was observed between 20 and 30 kHz. The minimal EP threshold to noise burst was 3 X 10(-4) - 10(-3) Pa. The threshold for response to modulations in sound intensity was below 0.5 dB and about 0.1% for frequency modulations. Special attention was paid to the dependence of the auditory cortex EP on the temporal parameters of the acoustic stimuli: sound burst duration, rise time, and repetition rate. The data indicate that the porpoise auditory cortex is adapted to detect ultrasonic, brief, fast rising, and closely spaced sounds like echolocating clicks. PMID:3735161

Popov, V V; Ladygina, T F; Supin AYa

1986-05-01

263

The N2-P3 complex of the evoked potential and human performance  

NASA Technical Reports Server (NTRS)

The N2-P3 complex and other endogenous components of human evoked potential provide a set of tools for the investigation of human perceptual and cognitive processes. These multidimensional measures of central nervous system bioelectrical activity respond to a variety of environmental and internal factors which have been experimentally characterized. Their application to the analysis of human performance in naturalistic task environments is just beginning. Converging evidence suggests that the N2-P3 complex reflects processes of stimulus evaluation, perceptual resource allocation, and decision making that proceed in parallel, rather than in series, with response generation. Utilization of these EP components may provide insights into the central nervous system mechanisms modulating task performance unavailable from behavioral measures alone. The sensitivity of the N2-P3 complex to neuropathology, psychopathology, and pharmacological manipulation suggests that these components might provide sensitive markers for the effects of environmental stressors on the human central nervous system.

Odonnell, Brian F.; Cohen, Ronald A.

1988-01-01

264

Assessing sedation in critically ill children by bispectral index, auditory-evoked potentials and clinical scales  

Microsoft Academic Search

Objective  To evaluate the correlation and agreement between the bispectral index (BIS), middle latency auditory-evoked potential index\\u000a (AEP index), Ramsay scale (RS) and COMFORT scale (CS) for evaluation of the level of sedation in critically ill children.\\u000a \\u000a \\u000a \\u000a Design  Prospective observational study.\\u000a \\u000a \\u000a \\u000a Setting  Pediatric critical care unit.\\u000a \\u000a \\u000a \\u000a Patients  Seventy-seven critically ill children receiving sedation and mechanical ventilation.\\u000a \\u000a \\u000a \\u000a Measurements and results  Simultaneous recording of BIS, AEP index,

Adelaida Lamas; Jesús López-Herce; Luis Sancho; Santiago Mencía; Ángel Carrillo; Maria José Santiago; Vicente Martínez

2008-01-01

265

Addition of visual noise boosts evoked potential-based brain-computer interface.  

PubMed

Although noise has a proven beneficial role in brain functions, there have not been any attempts on the dedication of stochastic resonance effect in neural engineering applications, especially in researches of brain-computer interfaces (BCIs). In our study, a steady-state motion visual evoked potential (SSMVEP)-based BCI with periodic visual stimulation plus moderate spatiotemporal noise can achieve better offline and online performance due to enhancement of periodic components in brain responses, which was accompanied by suppression of high harmonics. Offline results behaved with a bell-shaped resonance-like functionality and 7-36% online performance improvements can be achieved when identical visual noise was adopted for different stimulation frequencies. Using neural encoding modeling, these phenomena can be explained as noise-induced input-output synchronization in human sensory systems which commonly possess a low-pass property. Our work demonstrated that noise could boost BCIs in addressing human needs. PMID:24828128

Xie, Jun; Xu, Guanghua; Wang, Jing; Zhang, Sicong; Zhang, Feng; Li, Yeping; Han, Chengcheng; Li, Lili

2014-01-01

266

Possible Long Term Effects of Chemical Warfare Using Visual Evoked Potentials  

PubMed Central

Some studies have already addressed the effects of occupational organic solvent exposure on the visually evoked potentials (VEPs). Visual system is an important target for Sulphur Mustard (SM) toxicity. A number of Iranian victims of Sulphur Mustard (SM) agent were apprehensive about the delay effect of SM on their vision and a possible delay effect of SM on their visual cortex. This investigation was performed on 34 individuals with a history of chemical exposure and a control group of 15 normal people. The Toennies electro-diagnosis device was used and its signals were saved as the latencies. The mean of N75, N140 and P100 of victims of chemical warfare (VCWs) and control group indicated no significant results (P>0.05). The VCWs did not show any visual symptoms and there was no clear deficit in their VEPs. PMID:25242846

Riazi, Abbas; Hafezi, Rhamatollah; Babaei, Mahmoud; Naderi, Mostafa

2014-01-01

267

Possible long term effects of chemical warfare using visual evoked potentials.  

PubMed

Some studies have already addressed the effects of occupational organic solvent exposure on the visually evoked potentials (VEPs). Visual system is an important target for Sulphur Mustard (SM) toxicity. A number of Iranian victims of Sulphur Mustard (SM) agent were apprehensive about the delay effect of SM on their vision and a possible delay effect of SM on their visual cortex. This investigation was performed on 34 individuals with a history of chemical exposure and a control group of 15 normal people. The Toennies electro-diagnosis device was used and its signals were saved as the latencies. The mean of N75, N140 and P100 of victims of chemical warfare (VCWs) and control group indicated no significant results (P>0.05). The VCWs did not show any visual symptoms and there was no clear deficit in their VEPs. PMID:25242846

Riazi, Abbas; Hafezi, Rhamatollah; Babaei, Mahmoud; Naderi, Mostafa

2014-09-01

268

Abnormal visual-evoked potentials in leukemic children after cranial radiation  

SciTech Connect

Visual-evoked potentials (VEPs) were studied in 55 asymptomatic children with leukemia or solid tumors in remission in order to detect subclinical demyelination of the optic pathway after CNS prophylaxis. In group I (11 patients with ALL studied prospectively), VEP latency was increased in ten after cranial radiation (CR) as compared with previous values. Group II (18 patients with ALL in maintenance) and group III (16 patients with ALL off therapy) were studied retrospectively and VEP latency was found above normal limits in 33 and 31%, respectively. In group IV (four patients with solid tumors and six with leukemia, all of whom received no CR), VEP latency was normal despite periodical intrathecal methotrexate administrations to five of them. The authors conclude that CR determines a slowing of conduction on VEP test, probably due to demyelination of the optic pathway, in a high proportion of patients. The future clinical significance of these findings must be established throughout a prolonged follow-up period.

Russo, A.; Tomarchio, S.; Pero, G.; Consoli, G.; Marina, R.; Rizzari, C.; Schiliro, G.

1985-01-01

269

A computational model for generation of the P300 evoked potential component.  

PubMed

The P300 is an endogenously evoked potential with amplitude and latency depending on the amount of information carried by the stimulus rather than its physical characteristics. It has been suggested that P300 is a manifestation of the context updating mechanism in the human working memory. We present a neural network-based model that mimics the learning and forgetting mechanisms of external stimuli in the human working memory that are believed to be responsible for P300 generation. A modified version of the Hebbian learning rule has been devised to govern the weight dynamics of the network. The model was validated by comparing the characteristics of simulated P300 with actual experimental findings such as the relationship between P300 amplitude and stimulus probability, and task relevance. The results show that the proposed P300 model mimics many aspects of the nervous system responsible for P300 generation. PMID:22974337

Bonala, Bharat K; Jansen, Ben H

2012-09-01

270

Reduced Quadriceps Motor-Evoked Potentials in an Individual with Unilateral Knee Osteoarthritis: A Case Report  

PubMed Central

One male with unilateral osteoarthritis (OA) of the knee underwent testing of corticospinal (CS) excitability (as quantified from motor-evoked potentials (MEPs) in the rectus femoris (RF) using transcranial magnetic stimulation) and quadriceps muscle strength. Baseline data indicated reduced MEP amplitudes in the RF of the affected limb compared to the unaffected limb. Increases in RF MEP amplitudes from both limbs were observed immediately following a 30-minute exercise session focusing on muscle strengthening. Following an 8-week muscle strengthening intervention, the participant exhibited increased MEP amplitudes and muscle strength in the affected limb. These findings suggest that alterations in peripheral muscle function found in patients with knee OA may have an origin centrally within the motor cortex and that interlimb differences may be evident in those with unilateral disease. These findings also suggest that CS excitability may be improved following a muscle strengthening intervention. PMID:22937446

Hunt, Michael A.; Zabukovec, Jeanie R.; Peters, Sue; Pollock, Courtney L.; Linsdell, Meghan A.; Boyd, Lara A.

2011-01-01

271

[Normal latencies of cortical somatosensory evoked potentials--an additional criterion for the diagnosis of Rett syndrome].  

PubMed

In four girls aged from 2 1/2 to 17 years with Rett's syndrome confirmed on the basis of clinical criteria, somatosensorically evoked cortical potentials were led off contralaterally on both sides following stimulation of the median nerve (Med SEP). Like three other children with Rett's syndrome reported by Verma et al. (1987) the present author's patients had normal latency times. Determination of normal latency times for somatosensorically evoked potentials may thus be regarded as an important additional diagnostic criterion for the diagnosis of Rett's syndrome. PMID:2716239

Görke, W

1989-01-01

272

Inhibitory interactions in the human vision system revealed in pattern-evoked potentials.  

PubMed Central

1. Visual evoked potentials (v.e.p.s) were recorded from human adults to investigate orientation-specific neural interactions. The stimuli were the sum of two gratings, sinusoidally modulated in space and time at different frequencies. Recordings were made for one grating (test) alone, and with another superimposed grating (mask), oriented parallel or orthogonal to the test. The amplitude and phase of the v.e.p.s at twice the test modulation frequency (second harmonic) was measured as a function of test contrast to produce contrast-response curves. 2. Orthogonal masks attenuated considerably the amplitude of v.e.p.s. The attenuation at any given contrast was approximately proportional, or multiplicative, lowering the slope of the contrast-response curve, without affecting significantly the extrapolated threshold. Parallel masks also attenuated v.e.p. amplitudes but in a different way, leaving the slope of the contrast-response curves unchanged, while elevating threshold. 3. The attenuation by orthogonal masks occurred over a wide range of test spatial frequencies, from 0.8 to 8 cycles/deg. For any given test spatial frequency, the most effective masks were those of spatial frequency similar to or lower than the test. Masks of spatial frequency 1.5 octaves higher than the test did not attenuate v.e.p. amplitudes. 4. The mask temporal frequency for maximal attenuation of v.e.p. amplitude was around 12 Hz, with stationary masks having little effect. 5. Under most conditions, the phase of the second harmonic of the v.e.p., increased with increasing contrast (phase advance). Superimposition of a parallel mask abolished phase advance, while orthogonal masks increased it. 6. Comparisons with single cortical unit and evoked potential recordings in cats suggest that the attenuation by orthogonal masks reflects intracortical inhibitory interactions between cell populations of different orientation preference. PMID:3681721

Burr, D C; Morrone, M C

1987-01-01

273

Effects of Age and Degree of Hearing Loss on the Agreement and Correlation Between Sound Field Audiometric Thresholds and Tone Burst Auditory Brainstem Response Thresholds in Infants and Young Children  

Microsoft Academic Search

Background\\/Purpose: Early hearing rehabilitation programs eventually require measurement of the hearing threshold cutoff values over the whole range of speech frequencies. With tone burst auditory brainstem responses, excellent agreement and correlation between evoked-potential and behavioral thresholds have been demonstrated by previous studies. This study investigated the effects of different ages and degrees of hearing loss on the agreement and correlation

Chung-Yi Lee; Fu-Shan Jaw; Shin-Liang Pan; Tai-Hsin Hsieh; Chuan-Jen Hsu

274

Morphine modifies the cingulate-operculum network underlying painful rectal evoked potentials.  

PubMed

The effect of opioids on brain networks underlying rectal evoked potentials (EPs) has never been investigated. This study utilized brain source connectivity to explore whether morphine induced changes in brain networks underlying painful rectal EPs would reflect changes in pain scores due to morphine. Twenty healthy volunteers were included in this placebo-controlled cross-over study. Sensory and pain thresholds to electrically induced rectal stimulation were taken before (baseline) and 70 min after placebo/morphine (30 mg) administration. The stimulation intensity required to evoke moderate pain at baseline was employed for EPs. The pain score of this stimulation intensity was recorded again 70 min after placebo/morphine administration. 62-channel EPs were recorded for both arms. Amplitudes and latencies were analysed and brain source connectivity analysis was done. Changes in any of the parameters describing EPs were correlated to changes in subjective pain ratings. Morphine increased sensory and pain thresholds by 28.8% and 27.5% (P ? 0.02). The pain score corresponding to moderate pain at baseline was attenuated in both placebo and morphine arms by 14.5% and 37.5% (P < 0.05). There was a 33.9% reduction in EP amplitudes due to placebo (P < 0.05), whereas EP amplitudes remained stable due to morphine. A dominating cingulate-operculum network to rectal pain was seen. Cingulate source shifted anteriorly in the morphine arm (P < 0.001) and this shift was positively correlated to the change in the pain score (r = 0.6, P < 0.05). These findings indicate that visceral pain relief due to morphine is associated with reorganization within cingulate cortex, which may be used as a biomarker of opioid effects. PMID:24184388

Lelic, D; Olesen, A E; Gregersen, H; Dahan, A; Kolesnikov, Y; Drewes, A M

2014-02-01

275

Electrocorticogram spectral analysis and somatosensory evoked potentials as tools to assess electrical stunning efficiency in ducks.  

PubMed

1. Fast Fourier transformations (FFTs) of electrocorticogram (ECoG) signals and averaging of somatosensory evoked potentials (SEPs) were used for assessing the impact of electrical stunning of ducks in a waterbath set to deliver a constant current of 150 mA, 600 Hz alternating current (AC) for 4 s. The effectiveness of stunning was determined on the basis of induction of epileptiform activity in the ECoG followed by a decrease in total power content to less than 10% of pre-stun values and abolition of SEPs. 2. One out of 10 birds was killed by the stun. FFT analysis of the ECoG signals of the remaining 9 birds showed that only one bird had a decrease of the total power to less than 10% of the pre-stun values for up to 70 s post-stun. The SEPs were retained in 6 out of 9 ducks and and 4 of them retained the evoked responses throughout the post-stun period. In the two birds showing abolition of SEPs, this was associated with a decrease in the total power content to below 10% of the pre-stun value. 3. The present experiment confirmed that the abolition of SEPs and the decrease of the total power below 10% of the pre-stun value for assessing unconsciousness after an electrical stunning in various species are also applicable to ducks. Based on this, it is concluded that electrical waterbath stunning of ducks using 150 mA of 600 Hz AC is ineffective. PMID:15327129

Beyssen, C; Babile, R; Fernandez, X

2004-06-01

276

Binaural Interaction in Specific Language Impairment: An Auditory Evoked Potential Study  

ERIC Educational Resources Information Center

The aim of the study was to examine whether auditory binaural interaction, defined as any difference between binaurally evoked responses and the sum of monaurally evoked responses, which is thought to index functions involved in the localization and detection of signals in background noise, is atypical in a group of children with specific language…

Clarke, Elaine M; Adams, Catherine

2007-01-01

277

Amplitude Changes of the Electrically Evoked Compound Action Potential in Children with Cochlear Implants: Preliminary Results  

PubMed Central

Objective Use of electrical instead of acoustical stimulation has made much objective electrophysiological evaluation possible. This is useful for management process of young children before and after the cochlear implant. These evaluations have been used for assessment of neuronal survival before cochlear implant and for monitoring of prosthesis function during and after the surgery. Electrically evoked compound action potential is one of these tests which makes a valid and reliable objective evaluation possible. The aim of this study was to evaluate the potential's amplitude changes three months after receiving the device in pediatric cochlear implant recipients. Methods In this longitudinal study, changes of the potential's amplitude in four given electrodes in four sessions after receiving the device are evaluated by approximately one month intervals in children implanted in Amir Alam and Hazrat-e-Rasoul hospitals, Tehran in July to December 2007. Findings The mean amplitude of the electrodes did not significantly change in different sessions, while there was significant difference between the first and the other electrodes’ responses in every session (P<0.05). Conclusion Due to high reliability of the responses, the clinician can fit the speech processor for a long time. Better responses in apical electrodes may lead to develop an effective coding strategy. PMID:23056819

Pourjavid, Alireza; Adel Ghahraman, Mansoureh; Sedaie, Mahin; Emamjome, Hessam-al-din; Mobedshahi, Farzad; Abbasalipour Kabirrah, Parvaneh

2011-01-01

278

USEFULLNESS OF FUNCTIONAL MRI ASSOCIATED WITH PET SCAN AND EVOKED POTENTIALS IN THE EVALUATION OF BRAIN FUNCTIONS AFTER  

E-print Network

USEFULLNESS OF FUNCTIONAL MRI ASSOCIATED WITH PET SCAN AND EVOKED POTENTIALS IN THE EVALUATION CEREBRALES GRAVES : résultats préliminaires. Key Words : brain injury, coma, MRI, functional imaging usefulness of functional MRI (fMRI) for the evaluation of brain functions after severe brain injury, when

Paris-Sud XI, Université de

279

Cyclopiazonic acid disturbs the regulation of cytosolic calcium when repetitive action potentials are evoked in Dionaea traps  

Microsoft Academic Search

Evoking of action potentials (APs) in the trap of Dionaea muscipula Ellis at intervals shorter than 20 s caused a gradual decrease in the amplitude of the APs. At longer intervals the amplitude was constant. The calcium ionophore A23187 (1 µM) caused a considerable decrease of AP amplitude. Pretreatment of a segment of the Dionaea trap with cyclopiazonic acid (CPA),

Kazimierz Trebacz; Marion B. Busch; Zygmunt Hejnowicz; Andreas Sievers

1996-01-01

280

Short-Latency Median-Nerve Somatosensory-Evoked Potentials and Induced Gamma-Oscillations in Humans  

ERIC Educational Resources Information Center

Recent studies have suggested that cortical gamma-oscillations are tightly linked with various forms of physiological activity. In the present study, the dynamic changes of intracranially recorded median-nerve somatosensory-evoked potentials (SEPs) and somatosensory-induced gamma-oscillations were animated on a three-dimensional MR image, and the…

Fukuda, Miho; Nishida, Masaaki; Juhasz, Csaba; Muzik, Otto; Sood, Sandeep; Chugani, Harry T.; Asano, Eishi

2008-01-01

281

Use of auditory evoked potentials for intra-operative awareness in anesthesia: a consciousness-based conceptual model.  

PubMed

Auditory evoked potentials (AEPs) have been used as a measure of the depth of anesthesia during the intra-operative process. AEPs are classically divided, on the basis of their latency, into first, fast, middle, slow, and late components. The use of auditory evoked potential has been advocated for the assessment of Intra-operative awareness (IOA), but has not been considered seriously enough to universalize it. It is because we have not explored enough the impact of auditory perception and auditory processing on the IOA phenomena as well as on the subsequent psychological impact of IOA on the patient. More importantly, we have seldom tried to look at the phenomena of IOP from the perspective of consciousness itself. This perspective is especially important because many of IOA phenomena exist in the subconscious domain than they do in the conscious domain of explicit recall. Two important forms of these subconscious manifestations of IOA are the implicit recall phenomena and post-operative dreams related to the operation. Here, we present an integrated auditory consciousness-based model of IOA. We start with a brief description of auditory awareness and the factors affecting it. Further, we proceed to the evaluation of conscious and subconscious information processing by auditory modality and how they interact during and after intra-operative period. Further, we show that both conscious and subconscious auditory processing affect the IOA experience and both have serious psychological implications on the patient subsequently. These effects could be prevented by using auditory evoked potential during monitoring of anesthesia, especially the mid-latency auditory evoked potentials (MLAERs). To conclude our model with present hypothesis, we propose that the use of auditory evoked potential should be universal with general anesthesia use in order to prevent the occurrences of distressing outcomes resulting from both conscious and subconscious auditory processing during anesthesia. PMID:25326858

Dong, Xuebao; Suo, Puxia; Yuan, Xin; Yao, Xuefeng

2015-01-01

282

Differential effects of endogenous lithium on neurobehavioural functioning: a study on auditory evoked potentials.  

PubMed

Lithium occurs naturally in food and water. Low environmental concentrations in drinking water are associated with mental illnesses and behavioural offences, and at therapeutic dosages it is used to treat psychiatric (especially affective) disorders, partly by facilitating serotonergic (5-HT) neurotransmission. As little is known about the psychophysiological role of nutritional lithium in the general population, endogenous lithium concentrations were hypothesised to be associated with measurable effects on emotional liability and the loudness dependence (LD) that is proposed as one of the most valid indicators of 5-HT neurotransmission. Auditory evoked potentials of healthy volunteers [N=36] with high (>2.5 microg/l) or low (<1.5 microg/l) lithium serum concentrations were recorded. Emotional liability was assessed using the Brief Symptom Inventory (BSI). Low-lithium levels correlated with Somatisation while correlations between lithium and LD were not significant. Still, LD correlated positively with Paranoid Ideation, negatively with Anxiety and, in the high-lithium group, inversely with further aspects of emotional liability (Depression, Psychological Distress). In conclusion, the effects of low levels of endogenous lithium are associated with emotional liability, and high levels with some protective effects, although findings remain inconclusive regarding LD. Potential benefits of endogenous lithium on neurobehavioural functioning, especially in high-risk individuals, would have public health implications. PMID:20452041

Norra, Christine; Feilhauer, Johanna; Wiesmüller, Gerhard Andreas; Kunert, Hanns Jürgen

2010-06-30

283

Lexicality and modality effects on evoked potentials in a memory-scanning task.  

PubMed

Event-related potentials, as well as reaction times and performance accuracies, were recorded from normal young adults during the performance of a memory-scanning task, in response to the first and second items of the memorized set and to the probe. Stimuli included computer-generated digits, presented by earphones as speech (lexical auditory) or on a screen (lexical visual), meaningless voices (nonlexical auditory) with precisely the same frequency contents as the digits, or meaningless shapes with the very same colors and contours as the digits (nonlexical visual). The evoked potentials' late positivity (P3) to memorized items was earlier to auditory than to visual stimuli. P3 to memorized items and to probes was earlier to lexical than to nonlexical stimuli. P3 amplitudes to both memorized items and probes were smaller with auditory stimuli. Assuming P3 latency to reflect processing time and amplitude to reflect attentional allocation (effort) to the task-relevant stimuli, the results support phonological representations during processing in short-term memory, with nonauditory and nonlexical stimuli requiring more processing time and effort. A significant electrode x modality x lexicality interaction may suggest that stimuli of different modalities and lexicality involve variations in the relative contributions of the brain structures involved in their processing. PMID:8193910

Pratt, H; Erez, A; Geva, A B

1994-04-01

284

The locus of color sensation: Cortical color loss and the chromatic visual evoked potential  

PubMed Central

Color losses of central origin (cerebral achromatopsia and dyschromatopsia) can result from cortical damage and are most commonly associated with stroke. Such cases have the potential to provide useful information regarding the loci of the generation of the percept of color. One available tool to examine this issue is the chromatic visual evoked potential (cVEP). The cVEP has been used successfully to objectively quantify losses in color vision capacity in both congenital and acquired deficiencies of retinal origin but has not yet been applied to cases of color losses of cortical origin. In addition, it is not known with certainty which cortical sites are responsible for the generation of the cVEP waveform components. Here we report psychophysical and electrophysiological examination of a patient with color deficits resulting from a bilateral cerebral infarct in the ventral occipitotemporal region. Although this patient demonstrated pronounced color losses of a general nature, the waveform of the cVEP remains unaffected. Contrast response functions of the cVEP are also normal for this patient. The results suggest that the percept of color arises after the origin of the cVEP and that normal activity in those areas that give rise to the characteristic negative wave of the cVEP are not sufficient to provide for the normal sensation of color. PMID:23986535

Crognale, Michael A.; Duncan, Chad S.; Shoenhard, Hannah; Peterson, Dwight J.; Berryhill, Marian E.

2013-01-01

285

Effect of isoflurane on somatosensory evoked potentials in a rat model.  

PubMed

Somatosensory evoked potentials (SEPs) are widely used in the clinic as well as research to study the functional integrity of the different parts of sensory pathways. However, most general anesthetics, such as isoflurane, are known to suppress SEPs, which might affect the interpretation of the signals. In animal studies, the usage of anesthetics during SEP measurements is inevitable due to which detailed effect of these drugs on the recordings should be known. In this paper, the effect of isoflurane on SEPs was studied in a rat model. Both time and frequency properties of the cortical recordings generated by stimulating the tibial nerve of rat's hindlimb were investigated at three different isoflurane levels. While the anesthetic agent is shown to generally suppress the amplitude of the SEP, the effect was found to be nonlinear influencing more substantially the latter part of waveform. This finding will potentially help us in future work aiming at separating the effects of anesthetics on SEP from those due to injury in the ascending neural pathways. PMID:25570940

Kortelainen, Jukka; Vipin, Ashwati; Thow Xin Yuan; Mir, Hasan; Thakor, Nitish; Al-Nashash, Hasan; All, Angelo

2014-08-01

286

Face-Evoked Steady-State Visual Potentials: Effects of Presentation Rate and Face Inversion  

PubMed Central

Face processing can be explored using electrophysiological methods. Research with event-related potentials has demonstrated the so-called face inversion effect, in which the N170 component is enhanced in amplitude and latency to inverted, compared to upright, faces. The present study explored the extent to which repetitive lower-level visual cortical engagement, reflected in flicker steady-state visual evoked potentials (ssVEPs), shows similar amplitude enhancement to face inversion. We also asked if inversion-related ssVEP modulation would be dependent on the stimulation rate at which upright and inverted faces were flickered. To this end, multiple tagging frequencies were used (5, 10, 15, and 20?Hz) across two studies (n?=?21, n?=?18). Results showed that amplitude enhancement of the ssVEP for inverted faces was found solely at higher stimulation frequencies (15 and 20?Hz). By contrast, lower frequency ssVEPs did not show this inversion effect. These findings suggest that stimulation frequency affects the sensitivity of ssVEPs to face inversion. PMID:23205009

Gruss, L. Forest; Wieser, Matthias J.; Schweinberger, Stefan R.; Keil, Andreas

2012-01-01

287

Somatosensory evoked potentials after multisegmental lower limb stimulation in focal lesions of the lumbosacral spinal cord  

PubMed Central

OBJECTIVES—Recording techniques permit the separate analysis of the response from cauda equina roots and the spinal potential that is probably generated by the activation of dorsal horn cells. To improve the functional assessment of focal lesions of the lumbosacral cord, lower limb somatosensory evoked potentials (SEPs) were measured by multisegmental stimulation.?METHODS—Common peroneal and tibial nerves SEPs were recorded in 14 patients in whom MRI demonstrated compressive cord damage ranging from T9 to L1 levels. SEPs were recorded in each patient at the lumbar level (cauda equina response), lower thoracic level (spinal response), and from the scalp (cortical response).?RESULTS—Abnormalities in spinal response occurred in 50% and 70% of tibial and common peroneal nerve SEPs respectively; these findings were well explained by the radiological compression level, involving in most of the patients lumbar rather than sacral myelomeres. The SEPs were often more effective than the clinical examination in showing the actual extension of damage.?CONCLUSIONS—The recording of spinal SEPs after multisegmental lower limb stimulation proved useful in assessing cord dysfunction and determining the cord levels mainly involved by the compression.?? PMID:10864611

Restuccia, D.; Insola, A.; Valeriani, M.; Santilli, V.; Bedini, L.; Le Pera, D.; Barba, C.; Denaro, F.; Tonali, P.

2000-01-01

288

Echo-location and evoked potentials of bats after ablation of inferior colliculus.  

PubMed

1. Echo-location and evoked potentials of blinded Yuma bats (Myotis yumanensis) were studied before and after ablation of the inferior colliculus (I.C.). A task of obstacle-avoidance was given to the bats: hits and misses of strands in the flight path were counted. Orientation sounds emitted by the bats during flight were recorded.2. Bilateral ablation of the dorso-medial region of I.C. including the internuclear cortex and commissure had no effect on obstacle-avoidance performance. The bats avoided even strands of 0.2 mm diameter with orientation sounds.3. Bilateral ablation of the dorsal half of I.C. including the external nucleus (lateral cortex) also had no effect on echo-location.4. Bilateral ablation of the ventral half of I.C. caused severe deficiency in ability to avoid obstacles. The main nucleus appeared to be very important for echo-location. When bilateral ablation including the main nucleus was moderate, the bats failed to avoid strands of less than 0.5 mm diameter in spite of detecting them, but avoided large obstacles such as 3.7 mm strands. With severe bilateral ablation including the main nucleus, the bats did not avoid even the 3.7 mm strands in spite of frequent emission of orientation sounds, but often avoided crashing into the wall.5. Severe unilateral ablation of I.C. including the main nucleus and a part of the lateral lemniscus had no effect on ability to avoid obstacles. Since sound localization by such bats are not explained by Van Bergeijk's model based on Békésy's, a modification of Van Bergeijk's model has to be considered.6. Of the positive evoked potentials recorded with an active electrode placed at the dorsal surface of I.C., the slow component with a 7-9 msec peak latency reflected activity of inferior collicular neurones, while the fast component (N(4)) with a 3 msec peak latency represented activity of ascending lateral lemniscal fibres. PMID:5387030

Suga, N

1969-08-01

289

Echo-location and evoked potentials of bats after ablation of inferior colliculus  

PubMed Central

1. Echo-location and evoked potentials of blinded Yuma bats (Myotis yumanensis) were studied before and after ablation of the inferior colliculus (I.C.). A task of obstacle-avoidance was given to the bats: hits and misses of strands in the flight path were counted. Orientation sounds emitted by the bats during flight were recorded. 2. Bilateral ablation of the dorso-medial region of I.C. including the internuclear cortex and commissure had no effect on obstacle-avoidance performance. The bats avoided even strands of 0·2 mm diameter with orientation sounds. 3. Bilateral ablation of the dorsal half of I.C. including the external nucleus (lateral cortex) also had no effect on echo-location. 4. Bilateral ablation of the ventral half of I.C. caused severe deficiency in ability to avoid obstacles. The main nucleus appeared to be very important for echo-location. When bilateral ablation including the main nucleus was moderate, the bats failed to avoid strands of less than 0·5 mm diameter in spite of detecting them, but avoided large obstacles such as 3·7 mm strands. With severe bilateral ablation including the main nucleus, the bats did not avoid even the 3·7 mm strands in spite of frequent emission of orientation sounds, but often avoided crashing into the wall. 5. Severe unilateral ablation of I.C. including the main nucleus and a part of the lateral lemniscus had no effect on ability to avoid obstacles. Since sound localization by such bats are not explained by Van Bergeijk's model based on Békésy's, a modification of Van Bergeijk's model has to be considered. 6. Of the positive evoked potentials recorded with an active electrode placed at the dorsal surface of I.C., the slow component with a 7-9 msec peak latency reflected activity of inferior collicular neurones, while the fast component (N4) with a 3 msec peak latency represented activity of ascending lateral lemniscal fibres. PMID:5387030

Suga, N.

1969-01-01

290

The Effectiveness of FES-Evoked EMG Potentials to Assess Muscle Force and Fatigue in Individuals with Spinal Cord Injury  

PubMed Central

The evoked electromyographic signal (eEMG) potential is the standard index used to monitor both electrical changes within the motor unit during muscular activity and the electrical patterns during evoked contraction. However, technical and physiological limitations often preclude the acquisition and analysis of the signal especially during functional electrical stimulation (FES)-evoked contractions. Hence, an accurate quantification of the relationship between the eEMG potential and FES-evoked muscle response remains elusive and continues to attract the attention of researchers due to its potential application in the fields of biomechanics, muscle physiology, and rehabilitation science. We conducted a systematic review to examine the effectiveness of eEMG potentials to assess muscle force and fatigue, particularly as a biofeedback descriptor of FES-evoked contractions in individuals with spinal cord injury. At the outset, 2867 citations were identified and, finally, fifty-nine trials met the inclusion criteria. Four hypotheses were proposed and evaluated to inform this review. The results showed that eEMG is effective at quantifying muscle force and fatigue during isometric contraction, but may not be effective during dynamic contractions including cycling and stepping. Positive correlation of up to r = 0.90 (p < 0.05) between the decline in the peak-to-peak amplitude of the eEMG and the decline in the force output during fatiguing isometric contractions has been reported. In the available prediction models, the performance index of the eEMG signal to estimate the generated muscle force ranged from 3.8% to 34% for 18 s to 70 s ahead of the actual muscle force generation. The strength and inherent limitations of the eEMG signal to assess muscle force and fatigue were evident from our findings with implications in clinical management of spinal cord injury (SCI) population. PMID:25025551

Ibitoye, Morufu Olusola; Estigoni, Eduardo H.; Hamzaid, Nur Azah; Wahab, Ahmad Khairi Abdul; Davis, Glen M.

2014-01-01

291

Auditory evoked responses in gestational diabetics.  

PubMed

Electrophysiological correlates of sensory function in diabetic pregnancy have not been documented. Present study reports changes in Auditory evoked responses (AER) in gestational diabetics when compared with normal pregnant controls. Human AER are generally classified into early Auditory brainstem responses (AER), Mid latency responses (MLR) and late Slow vertex responses (SVR). These potentials were recorded in 20 women with diabetic pregnancy using Ag/AgCl electrodes from Cz-A1 and Cz-A2 position on MEB 5200 Neuropack II ... plus (Nihon Kohden, Japan) Evoked Potential Recorder. The evoked potentials in gestational diabetics were compared with 20 age matched normal pregnant women using Student's t-test. Absolute latencies of waves I to V, Inter peak latencies I-III and I-V of ABR were significantly increased whereas amplitude of wave V decreased in diabetic pregnant women. No significant change in latency of any component of MLR was observed between the two groups whereas significant prolongation of latencies of all components of SVR was observed in diabetic pregnant women as compared to normal control group. These findings indicate prolongation of both peripheral transmission time (PTT) and central transmission time (CTT) in diabetic pregnant females. Prolongation of latencies of SVR components in this study implicates cortex in the central diabetic neuropathy in women with gestational diabetes. PMID:12708127

Chaudhari, Lalita; Tandon, O P; Vaney, N; Agarwal, N

2003-01-01

292

Nicotine suppresses the P13 auditory evoked potential by acting on the pedunculopontine nucleus in the rat  

Microsoft Academic Search

We identified a potential novel site of action for nicotine (NIC) since (a) systemic injection of NIC led to a dose-dependent decrease in the amplitude of the sleep state-dependent, vertex-recorded, P13 midlatency auditory evoked potential (generated by the reticular activating system, RAS), (b) localized injections of a nicotinic receptor antagonist into the pedunculopontine nucleus (PPN, the cholinergic arm of the

N. Mamiya; R. Buchanan; T. Wallace; R. D. Skinner; E. Garcia-Rill

2005-01-01

293

3D Topographic Study of the Diode Laser Evoked Potentials (LEPs) to Painful Stimulation of the Trigeminal Sensory Area  

Microsoft Academic Search

A diode laser attached with an optic fiber is flexible and adequate for painful cutaneous stimulation. The brain potentials elicited by diode laser stimulation reflect activation of thin-myelinated afferent fibers. This study examined the use of diode laser evoked potentials (LEPs) elicited from the left\\/right ophthalmic and maxillary branch of the trigeminal nerve. Twelve males (age: 26.3 ± 4.5) participated

Kadir Durak; Andrew C. N. Chen; Lars Arendt-Nielsen

2004-01-01

294

Functional correlates with left-right asymmetry of visual evoked potentials in stroke patients: Modeling and experimental results  

Microsoft Academic Search

Objective: To determine the correlation between a clinical measure of function in patients after first stroke and left-right scalp amplitude of visual evoked potentials using a theoretical model of the head.Design: A random sample of first-stroke patients underwent routine function measurement and investigation of left-right scalp potential asymmetry. Results of the encephalographic tests were compared with those of a healthy

Haim Ring; Leah Bar; Shimon Abboud

1999-01-01

295

Recognition of stimulus displays: An electrophysiological analysis. [human evoked potentials as control inputs  

NASA Technical Reports Server (NTRS)

Late components of evoked waveforms recorded from the frontal areas of the brain are correlated with an observer's interpretation of a stimulus display. The possible use of such signals as control inputs is discussed.

Johnston, V. S.

1975-01-01

296

HYPOTHERMIA AND CHLOROPENT ANESTHESIA DIFFERENTIALLY AFFECT THE FLASH EVOKED POTENTIALS OF HOODED RATS  

EPA Science Inventory

Anesthetics and body temperature alterations are both known to alter parameters of sensory-evoked responses. However few studies have quantitatively assessed the contributions of hypothermia to anesthetic-induced changes. Two experiments were performed. In the first, chronically ...

297

Change in auditory evoked potential index and bispectral index during induction of anesthesia with anesthetic drugs.  

PubMed

The aim of this study was to evaluate the efficacy of the auditory evoked potential (AEP) index (aepEX) as an assessment tool for hypnosis during induction of various anesthetic drugs, and to compare its performance to that of the bispectral index (BIS). A total of 45 cases were divided into three groups based on the drugs used for anesthesia. Before anesthetic induction, BIS and AEP monitors were initiated. Anesthesia was induced through intravenous injection (IV) as follows: MP (n = 15) group, midazolam (0.1 mg/kg IV); TP (n = 15) group, thiopental (4 mg/kg IV); and KP (n = 15) group, ketamine (2 mg/kg IV). After loss of response (LOR), an infusion of 3 ?g/ml propofol via a target-controlled infusion was initiated in all groups. AepEX and BIS were measured in the waking state (baseline) and at LOR (1 min after LOR), pre-intubation (1 min after previous intubation) and post-intubation (1 min after tracheal intubation finished). The value of aepEX significantly decreased in all groups with LOR and that of BIS also decreased except of KP group. No significant difference were observed in BIS values between baseline and LOR in the KS group. The aepEX might be more useful than BIS for hypnosis monitoring during anesthetic induction, particularly when drugs such as ketamine are used. PMID:25427598

Matsushita, Sachiko; Oda, Shinya; Otaki, Kei; Nakane, Masaki; Kawamae, Kaneyuki

2014-11-27

298

Cortical inhibition and habituation to evoked potentials: relevance for pathophysiology of migraine.  

PubMed

Dysfunction of neuronal cortical excitability has been supposed to play an important role in etiopathogenesis of migraine. Neurophysiological techniques like evoked potentials (EP) and in the last years non-invasive brain stimulation techniques like transcranial magnetic stimulation (TMS) and transcranial direct current stimulation gave important contribution to understanding of such issue highlighting possible mechanisms of cortical dysfunctions in migraine. EP studies showed impaired habituation to repeated sensorial stimulation and this abnormality was confirmed across all sensorial modalities, making defective habituation a neurophysiological hallmark of the disease. TMS was employed to test more directly cortical excitability in visual cortex and then also in motor cortex. Contradictory results have been reported pointing towards hyperexcitability or on the contrary to reduced preactivation of sensory cortex in migraine. Other experimental evidence speaks in favour of impairment of inhibitory circuits and analogies have been proposed between migraine and conditions of sensory deafferentation in which down-regulation of GABA circuits is considered the more relevant pathophysiological mechanism. Whatever the mechanism involved, it has been found that repeated sessions of high-frequency rTMS trains that have been shown to up-regulate inhibitory circuits could persistently normalize habituation in migraine. This could give interesting insight into pathophysiology establishing a link between cortical inhibition and habituation and opening also new treatment strategies in migraine. PMID:19209386

Brighina, Filippo; Palermo, Antonio; Fierro, Brigida

2009-04-01

299

Allelic variation in serotonin transporter function associated with the intensity dependence of the auditory evoked potential.  

PubMed

The intensity dependence of the auditory evoked potential (AEP) has been suggested as an indicator of central serotonergic function, a strong intensity dependence presumably reflecting low serotonergic activity. As individual differences in serotonergic neurotransmission can be accounted for in part by genetic variation in genes of the serotonergic pathway, we investigated whether a functional polymorphism in the promoter region of the serotonin transporter gene (5-HTTLPR) is associated with the AEP intensity dependence. Because dopaminergic influences on the intensity dependence have also been reported, we furthermore explored the role of a functional polymorphism in the dopamine D4 receptor gene (DRD4 exon III) in the modulation of the AEP intensity dependence. AEPs to tones of six intensity levels were recorded from 60 healthy young individuals, and N1/P2 linear as well as median slopes at central electrode sites were computed as measures of the AEP intensity dependence. Analyses of variance showed that there was a significant effect of the 5-HTTLPR on the AEP intensity dependence. Individuals with the ll genotype exhibited a stronger intensity dependence compared to individuals with the ls genotype. This effect was even more pronounced when DRD4 exon III was considered in the analyses. In conclusion, these findings provide further evidence for a role of serotonergic neurotransmission in the modulation of the AEP intensity dependence. The results also point to possible dopaminergic influences on the AEP intensity dependence. PMID:12627465

Strobel, A; Debener, S; Schmidt, D; Hünnerkopf, R; Lesch, K-P; Brocke, B

2003-04-01

300

An indicator of probable semicircular canal dehiscence: ocular vestibular evoked myogenic potentials to high frequencies.  

PubMed

The n10 component of the ocular vestibular evoked myogenic potential (oVEMP) to sound and vibration stimuli is a crossed response that has enhanced amplitude and decreased threshold in patients with CT-verified superior semicircular canal dehiscence (SSCD). However, demonstrating enhanced VEMP amplitude and reduced VEMP thresholds requires multiple trials and can be very time consuming and tiring for patients, so a specific indicator of probable SCD that is fast and not tiring would be preferred. Here we report a 1-trial indicator: that the oVEMP n10 in response to a very high frequency stimulus (4000 Hz), either air-conducted sound (ACS) or bone conducted vibration (BCV), is such a fast indicator of probable SCD. In 22 healthy subjects, oVEMP n10 at 4000 Hz was not detectable; however, in all 22 CT-verified SSCD patients tested, oVEMP n10 responses were clearly present to 4000 Hz to either ACS or BCV stimuli. PMID:23674567

Manzari, Leonardo; Burgess, Ann M; McGarvie, Leigh A; Curthoys, Ian S

2013-07-01

301

Tuning characteristics of ocular and cervical vestibular evoked myogenic potentials in intact and dehiscent ears.  

PubMed

Cervical and ocular vestibular evoked myogenic potentials (cVEMPs and oVEMPs) to air-conducted tone bursts (250-2000 Hz) were recorded in 14 patients with superior canal dehiscence (SCD) and 32 healthy controls. For cVEMPs, the most common 'optimal frequency' in control ears (48.2%) was 500 Hz; for oVEMPs, it was 1000 Hz (51.8%). We found a significant interaction between age and frequency, with a shift towards higher-frequency tuning in older subjects. cVEMP and oVEMP tuning in SCD was characterised by a broadening of amplitude and threshold tuning curves. The tendency of cVEMPs to tune to lower frequencies compared to oVEMP was enhanced in SCD. Differences in cVEMP and oVEMP 'optimal frequencies', demonstrated in 57.1% intact ears and 81.3% dehiscent ears, imply differences in the recruitment of hair cells generating these two reflexes. Age-matched oVEMP amplitudes provided excellent separation between SCD and control ears. Although cVEMP amplitudes overlapped between SCD and control ears, better separation was achieved by using a 2-kHz stimulus. PMID:22472299

Taylor, R L; Bradshaw, A P; Halmagyi, G M; Welgampola, M S

2012-01-01

302

Cholinergic Pairing with Visual Activation Results in Long-Term Enhancement of Visual Evoked Potentials  

PubMed Central

Acetylcholine (ACh) contributes to learning processes by modulating cortical plasticity in terms of intensity of neuronal activity and selectivity properties of cortical neurons. However, it is not known if ACh induces long term effects within the primary visual cortex (V1) that could sustain visual learning mechanisms. In the present study we analyzed visual evoked potentials (VEPs) in V1 of rats during a 4–8 h period after coupling visual stimulation to an intracortical injection of ACh analog carbachol or stimulation of basal forebrain. To clarify the action of ACh on VEP activity in V1, we individually pre-injected muscarinic (scopolamine), nicotinic (mecamylamine), ?7 (methyllycaconitine), and NMDA (CPP) receptor antagonists before carbachol infusion. Stimulation of the cholinergic system paired with visual stimulation significantly increased VEP amplitude (56%) during a 6 h period. Pre-treatment with scopolamine, mecamylamine and CPP completely abolished this long-term enhancement, while ?7 inhibition induced an instant increase of VEP amplitude. This suggests a role of ACh in facilitating visual stimuli responsiveness through mechanisms comparable to LTP which involve nicotinic and muscarinic receptors with an interaction of NMDA transmission in the visual cortex. PMID:19543405

Kang, Jun Il; Vaucher, Elvire

2009-01-01

303

Ocular vestibular evoked myogenic potential frequency tuning in certain Menière's disease.  

PubMed

Ocular vestibular evoked myogenic potentials (oVEMP) represent extraocular muscle activity in response to vestibular stimulation. To specify the value of oVEMP in the diagnostics of Menière's disease, the amplitude ratio between 500 and 1000 Hz stimuli was investigated. Thirty-nine patients with certain Menière's disease, i.e. definite Menière's disease with visualization of endolymphatic hydrops by magnetic resonance imaging and 19 age-matched healthy controls were enrolled in this study. oVEMP were recorded using 500 and 1000 Hz air-conducted tone bursts. For Menière's ears, the 500/1000 Hz amplitude ratio (mean ratio = 1.20) was significantly smaller when compared to unaffected ears of Menière's patients (mean ratio = 1.80; p = 0.008) or healthy controls (mean ratio = 1.81; p = 0.011). The amplitude ratio was neither correlated with the degree of endolymphatic hydrops nor with the duration of disease. While an older age was associated with a diminished amplitude ratio in healthy controls, there was no correlation between the amplitude ratio and age in Menière's ears. Hence, the calculation of the oVEMP 500/1000 Hz amplitude ratio may be a valuable diagnostic tool for Menière's disease. PMID:24530828

Jerin, Claudia; Berman, Albert; Krause, Eike; Ertl-Wagner, Birgit; Gürkov, Robert

2014-04-01

304

Selective attention to stimulus location modulates the steady-state visual evoked potential.  

PubMed Central

Steady-state visual evoked potentials (SSVEPs) were recorded from the scalp of human subjects who were cued to attend to a rapid sequence of alphanumeric characters presented to one visual half-field while ignoring a concurrent sequence of characters in the opposite half-field. These two-character sequences were each superimposed upon a small square background that was flickered at a rate of 8.6 Hz in one half-field and 12 Hz in the other half-field. The amplitude of the frequency-coded SSVEP elicited by either of the task-irrelevant flickering backgrounds was significantly enlarged when attention was focused upon the character sequence at the same location. This amplitude enhancement with attention was most prominent over occipital-temporal scalp areas of the right cerebral hemisphere regardless of the visual field of stimulation. These findings indicate that the SSVEP reflects an enhancement of neural responses to all stimuli that fall within the "spotlight" of spatial attention, whether or not the stimuli are task-relevant. Recordings of the SSVEP provide a new approach for studying the neural mechanisms and functional properties of selective attention to multi-element visual displays. PMID:8643478

Morgan, S T; Hansen, J C; Hillyard, S A

1996-01-01

305

Measuring steady-state visual evoked potentials from non-hair-bearing areas.  

PubMed

Steady-State Visual Evoked Potential (SSVEP)-based Brain-Computer Interface (BCI) applications have been widely applied in laboratories around the world in the recent years. Many studies have shown that the best locations to acquire SSVEPs were from the occipital areas of the scalp. However, for some BCI users such as quadriparetic patients lying face up during ventilation, it is difficult to access the occipital sites. Even for the healthy BCI users, acquiring good-quality EEG signals from the hair-covered occipital sites is inevitably more difficult because it requires skin preparation by a skilled technician and conductive gel usage. Therefore, finding an alternative approach to effectively extract high-quality SSVEPs for BCI practice is highly desirable. Since the non-hair-bearing scalp regions are more accessible by all different types of EEG sensors, this study systematically and quantitatively investigated the feasibility of measuring SSVEPs from non-hair-bearing regions, compared to those measured from the occipital areas. Empirical results showed that the signal quality of the SSVEPs from non-hair-bearing areas was comparable with, if not better than, that measured from hair-covered occipital areas. These results may significantly improve the practicality of a BCI system in real-life applications; especially used in conjunction with newly available dry EEG sensors. PMID:23366262

Wang, Yu-Te; Wang, Yijun; Cheng, Chung-Kuan; Jung, Tzyy-Ping

2012-01-01

306

Regional Hypothermia Inhibits Spinal Cord Somatosensory-Evoked Potentials without Neural Damage in Uninjured Rats  

PubMed Central

Abstract Both the therapeutic effects of regional hypothermia (RH) and somatosensory-evoked potentials (SSEP) have been intensively studied; however, the in vivo relationship between the two remains unknown. The primary focus of the current study was to investigate the impact of RH on SSEP in uninjured rats, as well as the neural safety of RH on neuronal health. An epidural perfusion model was used to keep local temperature steady by adjusting perfusion speed at 30°C, 26°C, 22°C, and 18°C for 30?min, respectively. Total hypothermic duration lasted up to 3?h. Neural signals were recorded at the end of each hypothermic period, as well as before cooling and after spontaneous rewarming. In addition, the Basso, Beattie, and Bresnahan (BBB) Locomotor Rating Scale was used to evaluate the effects of RH pre- and post-operative, combined with hematoxylin and eosin (H&E) and Fluoro-Jade C (FJC) staining. The results showed a marked declining trend in SSEP amplitude, as well as a significant prolongation in latency only during profound hypothermia (18°C). The BBB scale remained consistent at 21 throughout the entire process, signifying that no motor function injury was caused by RH. In addition, H&E and FJC staining did not show obvious histological injury. These findings firmly support the conclusion that RH, specifically profound RH, inhibits spinal cord SSEP in both amplitude and latency without neural damage in uninjured rats. PMID:22916828

Li, Ning; Tian, Lei; Wu, Wei; Lu, Huchen; Zhou, Yuan; Xu, Xiaoyu; Zhang, Xiangsheng

2013-01-01

307

Masking the Auditory Evoked Potential in TMS-EEG: A Comparison of Various Methods.  

PubMed

There is growing interest in combining transcranial magnetic stimulation (TMS) with electroencephalography (EEG). Because TMS pulses are accompanied by a clicking sound, it is very likely that part of the response in the EEG consists of an auditory evoked potential (AEP). Different methods have been applied to mask the sound of TMS. However, it is unclear which masking method is most effective in reducing the AEP. In this study we explore the presumed contribution of the AEP to the response and evaluate different ways to mask the TMS clicking sound. Twelve healthy subjects and one completely deaf subject participated in this study. Eight different masking conditions were evaluated in nine hearing subjects. The amplitude of the N100-P180 complex was compared between the different masking conditions. We were not able to completely suppress the N100-P180 when the coil was placed on top of the head. Using an earmuff or exposing the subjects to white or adapted noise caused a small but significant reduction in N100-P180 amplitude, but the largest reduction was achieved when combining a layer of foam, placed between coil and head, with white or adapted noise. The deaf subject also showed a N100-P180 complex. We conclude that both the TMS clicking sound and cortical activation by the magnetic pulse contribute to the N100-P180 amplitude. PMID:23996091

Ter Braack, Esther M; de Vos, Cecile C; van Putten, Michel J A M

2013-09-01

308

Dolphin and sea lion auditory evoked potentials in response to single and multiple swept amplitude tones.  

PubMed

Measurement of the auditory steady-state response (ASSR) is increasingly used to assess marine mammal hearing. These tests normally entail measuring the ASSR to a sequence of sinusoidally amplitude modulated tones, so that the ASSR amplitude function can be defined and the auditory threshold estimated. In this study, an alternative method was employed, where the ASSR was elicited by an amplitude modulated stimulus whose sound pressure level was slowly varied, or "swept," over a range of levels believed to bracket the threshold. The ASSR amplitude function was obtained by analyzing the resulting grand average evoked potential using a short-time Fourier transform. The suitability of this technique for hearing assessment of bottlenose dolphins and California sea lions was evaluated by comparing ASSR amplitude functions and thresholds obtained with swept amplitude and discrete, constant amplitude stimuli. When factors such as the number of simultaneous tones, the number of averages, and the frequency analysis window length were taken into account, the performance and time required for the swept-amplitude and discrete stimulus techniques were similar. The decision to use one technique over another depends on the relative importance of obtaining suprathreshold information versus the lowest possible thresholds. PMID:21877816

Finneran, James J; Mulsow, Jason; Schlundt, Carolyn E; Houser, Dorian S

2011-08-01

309

Clinical uses of cervical vestibular-evoked myogenic potential testing in pediatric patients.  

PubMed

To demonstrate the feasibility and clinical significance of cervical vestibular-evoked myogenic potential (cVEMP) test in pediatric patients.Retrospective review study was conducted in a pediatric tertiary care facility. A total of 278 patients were identified with adequate data, including medical notes, results of cVEMP, and imaging studies.Among the total of 278 pediatric patients, only 3 children were not able to finish the cVEMP test successfully. In about 90% of the cases, the cVEMP test was requested to investigate a patient's hearing loss and/or vestibular complaints. Over 90% of the cVEMP tests were ordered by specialists such as pediatric otolaryngologists or otologists. Obtained cVEMP results provided useful information in clinical diagnosis and management in all cases.It is feasible to conduct cVEMP testing in children, including infants, and cVEMP testing can provide valuable information in the diagnosis and management of hearing loss and vestibular impairment. This simple and noninvasive test should be embraced by pediatric professionals. PMID:25068952

Zhou, Guangwei; Dargie, Jenna; Dornan, Briana; Whittemore, Kenneth

2014-06-01

310

Sensory processing and the rubber hand illusion-an evoked potentials study.  

PubMed

The rubber hand illusion (RHI) paradigm-in which illusory bodily ownership is induced by synchronous tactile stimulation of a participant's (hidden) hand and a (visible) surrogate-allows one to investigate how the brain resolves conflicting multisensory evidence during perceptual inference. To identify the functional anatomy of the RHI, we used multichannel EEG, acquired under three conditions of tactile stimulation. Evoked potentials were averaged from EEG signals registered to the timing of brushstrokes to the participant's hand. The participant's hand was stroked either in the absence of an artificial hand (REAL) or synchronously with an artificial hand, which either lay in an anatomically plausible (CONGRUENT) or impossible (INCONGRUENT) position. The illusion was reliably elicited in the CONGRUENT condition. For right-hand stimulation, significant differences between conditions emerged at the sensor level around 55 msec after the brushstroke at left frontal and right parietal electrodes. Response amplitudes were smaller for illusory (CONGRUENT) compared with nonillusory (INCONGRUENT and REAL) conditions in the contralateral perirolandic region (pre- and postcentral gyri), superior and inferior parietal lobule, whereas veridical perception of the artificial hand (INCONGRUENT) amplified responses at a scalp region overlying the contralateral postcentral gyrus and inferior parietal lobule compared with the remaining two conditions. Left-hand stimulation produced similar contralateral patterns. These results are consistent with predictive coding models of multisensory integration and may reflect the attenuation of somatosensory precision that is required to resolve perceptual hypotheses about conflicting multisensory input. PMID:25170795

Zeller, Daniel; Litvak, Vladimir; Friston, Karl J; Classen, Joseph

2015-03-01

311

Validation of an adaptive signal enhancer in intraoperative somatosensory evoked potentials monitoring.  

PubMed

The conventional approach of ensemble averaging in intraoperative somatosensory evoked potentials (SEP) monitoring requires more than 500 trials to extract a reliable waveform for neurologic diagnosis. Previous studies showed that an adaptive signal enhancer (ASE) could increase the signal-to-noise ratio of input signals. This study assessed the accuracy and efficiency of the ASE in the extraction of neurologic normal human and abnormal rat SEP. Cortical and subcortical SEP were taken from 16 subjects undergoing scoliosis surgery. SEP extracted by ASE were compared with those obtained with 500-trial averaging in terms of peak latency, amplitude, and waveforms using correlation coefficients. An animal study composed of 18 rats was used to test the ASE in detecting abnormal SEP changes due to spinal cord compression. The results demonstrate the accuracy of ASE by showing very high correlations between ASE-processed SEP and ensemble averaging-processed SEP in waveforms, peak latencies, and amplitudes. The results also show the efficiency of the ASE in extracting SEP waveforms from 50 input trials, which provided waveforms of sufficiently high quality and latency/amplitude measurements equivalent to those obtained in 500 trials of conventional ensemble averaging. Because of its fast extraction ability, adaptive signal enhancement could be an appropriate alternative to conventional ensemble averaging in intraoperative spinal cord monitoring. PMID:15622127

Lam, Benny S C; Hu, Yong; Lu, William W; Luk, Keith D K

2004-01-01

312

The uses and interpretations of the motor-evoked potential for understanding behaviour.  

PubMed

The motor-evoked potential (MEP) elicited in peripheral muscles by transcranial magnetic stimulation (TMS) over human motor cortex is one of the hallmark measures for non-invasive quantification of cortical and spinal excitability in cognitive and clinical neuroscience. In the present article, we distinguish three main uses for MEPs in studies of behaviour: for understanding execution and performance of actions, as markers of physiological change in the motor system, and as read-out of upstream processes influencing the motor system. Common to all three approaches is the assumption that different experimental manipulations act on the balance of excitatory and inhibitory pre-synaptic (inter)neurons at the stimulation site; this in turn contributes to levels of (post-synaptic) excitability of cortico-spinal output projections, which ultimately determines the size of MEPs recorded from peripheral muscles. We discuss the types of inference one can draw from human MEP measures given that the detailed physiological underpinnings of MEPs elicited by TMS are complex and remain incompletely understood. Awareness of the different mechanistic assumptions underlying different uses of MEPs can help inform both study design and interpretation of results obtained from human MEP studies of behaviour. PMID:25563496

Bestmann, Sven; Krakauer, John W

2015-03-01

313

Auditory evoked potentials (AEP) methods for population-level assessment of hearing sensitivity in bottlenose dolphins  

NASA Astrophysics Data System (ADS)

A portable system for recording auditory evoked potentials (AEP) was developed to rapidly assess the hearing sensitivity of dolphins in air. The system utilizes a transducer embedded in a silicone suction cup to deliver amplitude modulated tones to the dolphin through the lower jaw. Frequencies tested range from 10-150 kHz and testing of both ears is completed within 90 min. AEP-determined thresholds from one subject were benchmarked against that subject's direct field behavioral audiogram to quantify variation between the two methods. To date, AEP audiograms have been obtained from over 30 bottlenose dolphins. Considerable individual variation in frequency-specific hearing sensitivity was observed. Some high-frequency hearing loss was observed in relatively young (early 20s) and old (35+ years) animals; conversely, age was not necessarily related to hearing loss as several animals greater than 40 years of age had good hearing sensitivity across the range of tested frequencies. Profound hearing loss typically occurred at higher frequencies. Decline in sensitivity was rapid in all cases and began between 50-60 kHz. Increased sample size of hearing sensitivity in dolphins suggest that the use of audiometric functions from single animals as representative of population level audiometry might be misleading.

Houser, Dorian; Finneran, James

2005-04-01

314

Modulation of the N30 generators of the somatosensory evoked potentials by the mirror neuron system.  

PubMed

The N30 component of the somatosensory evoked potential is known to be modulated by sensory interference, motor action, movement ideation and observation. We introduce a new paradigm in which the observation task of another person's hand movement triggers the somatosensory stimulus, inducing the N30 response in participants. In order to identify the possible contribution of the mirror neuron network (MNN) to this early sensorimotor processing, we analyzed the N30 topography, the event-related spectral perturbation and the inter-trial coherence on single electroencephalogram (EEG) trials, and we applied swLORETA to localize the N30 sources implicated in the time-frequency domain at rest and during observation, as well as the generators differentiating these two contextual brain states. We found that N30 amplitude increase correlated with increased contralateral precentral alpha, frontal beta, and contralateral frontal gamma power spectrum, and with central and precentral alpha and parietal beta phase-locking of ongoing EEG signals. We demonstrate specific activation of the contralateral post-central and parietal cortex where the angular gyrus (BA39), an important MNN node, is implicated in this enhancement during observation. We conclude that this part of the MNN, involved in proprioceptive processing and more complex body-action representations, is already active prior to somatosensory input and may enhance N30. PMID:24662578

Cebolla, A M; Palmero-Soler, E; Dan, B; Cheron, G

2014-07-15

315

Central auditory processing of noncontextual consonance in music: an evoked potential study.  

PubMed

The consonance of individual chords presented out of musical context, or the noncontextual consonance of chords, is usually defined as the absence of roughness, which is a sensation perceived when slightly mistuned frequencies are not clearly resolved in the cochlea. The present work uses evoked potentials to demonstrate that the absence of roughness is not sufficient to explain the entirety of noncontextual consonance perception. Presented with a random sequence of various pure-tone intervals (0-13 semitones), listeners' cerebral cortical activities distinguished these stimuli according to their noncontextual consonance in a manner consistent with standard musical practice, even when the intervals exceeded the critical bandwidth (approximately three semitones). The roughness-based model of noncontextual consonance could not account for this result because these wide intervals had indistinguishably low levels of roughness. Further, this effect was evident only in musicians, indicating plasticity in the underlying neural mechanisms. The results are consistent with the hypothesis that, although the absence of roughness may represent an important aspect of noncontextual consonance, properties of intervals other than those related to roughness also contribute to this perception, underpinned by neural activity in the central auditory system that can be plastically modified by experience. PMID:21218909

Itoh, Kosuke; Suwazono, Shugo; Nakada, Tsutomu

2010-12-01

316

Intraoperative Monitoring of Motor-Evoked Potentials for Supratentorial Tumor Surgery  

PubMed Central

Objective The purpose of this study was to assess the feasibility and clinical efficacy of motor evoked potential (MEP) monitoring for supratentorial tumor surgery. Methods Between 2010 and 2012, to prevent postoperative motor deterioration, MEP recording after transcranial stimulation was performed in 84 patients with supratentorial brain tumors (45 males, 39 females; age range, 24-80 years; median age, 58 years). MEP monitoring results were correlated with postoperative motor outcome compared to preoperative motor status. Results MEP recordings were stable in amplitude (<50% reduction in amplitude) during surgery in 77 patients (91.7%). No postoperative motor deficit was found in 66 out of 77 patients with stable MEP amplitudes. However, postoperative paresis developed in 11 patients. False negative findings were associated with edema in peri-resectional regions and postoperative bleeding in the tumor bed. MEP decrease in amplitude (>50%) occurred in seven patients (8.3%). However, no deficit occurred postoperatively in four patients following preventive management during the operation. Three patients had permanent paresis, which could have been associated with vascular injury during tumor resection. Conclusions MEP monitoring during supratentorial tumor surgery is feasible and safe. However, false negative MEP results associated with postoperative events may occur in some patients. To achieve successful monitoring, collaboration between surgeon, anesthesiologist and an experienced technician is mandatory. PMID:25328645

Lee, Jung Jae; Kim, Young Il; Hong, Jae Taek; Sung, Jae Hoon; Lee, Sang Won

2014-01-01

317

Sensory potentials evoked by tactile stimulation of different indentation velocities at the finger and palm.  

PubMed

Previous studies suggest that the rate of indentation of a tactile probe determines which skin mechanoreceptors are activated. To further investigate this possibility, indentations of 300 microm at velocities of 100 (T100) and 400 microm/ms (T400) were applied to the tip (FT) and the proximal phalanx of digit III (PP) and the thenar eminence (Pm) of ten healthy volunteers, and compared with responses after electrical stimulation at the FT. Compound sensory action potentials (CSAPs) were recorded from the median nerve through needle electrodes at the wrist and elbow. The maximal sensory conduction velocities (SNCVs) between wrist and elbow were similar with electrical and T400 stimulation, but on average were 15% lower with T100 stimulation (P < 0.001). With both indentation velocities, SNCVs were similar regardless of stimulation sites. Amplitudes of tactile CSAPs with FT stimulation were 1--2 microV at T400 and 0.3--0.4 microV at T100. The CSAP areas evoked by T100 stimulation showed a reduction from fingertip to proximal finger to palm (P < 0.05-0.005), whereas those obtained with T400 stimulation showed a reduction only at the palm (P < 0.05). The results support previous studies indicating that fast indentation at 400 microm/ms activated deeply placed Pacinian corpuscles as well as superficially situated Meissner corpuscles, whereas slower indentation at 100 microm/ms activated primarily Meissner corpuscles. PMID:11494275

Baba, M; Simonetti, S; Krarup, C

2001-09-01

318

Does athletic training in volleyball modulate the components of visual evoked potentials? A preliminary investigation.  

PubMed

This longitudinal study investigated visual evoked potentials (VEPs) in 11 young female volleyball players who participated in extensive training for 2 years. The control group consisted of 7 age-matched female students who were not involved in any regular sports activity. Recordings of VEPs were performed twice: baseline recording (i.e., before training began) and after 2 years of systematic, volleyball-specific athletic training. The effect of athletic training on visual signal conductivity was assessed by recording the latency of N75, P100 and N135 components of the VEPs waveform. Extensive experience with volleyball training reduced signal conductivity time through visual pathway. Specifically, the latency of P100 was reduced on average by 2.2 ms during binocular viewing. Moreover, athletes had reduced N75 latency (difference of 3.3 ms) for visual stimuli that generated greater response from peripheral retina. These results indicate that sport training can affect very early sensory processing in athletes. PMID:24716616

Zwierko, Teresa; Lubi?ski, Wojciech; Lesiakowski, Piotr; Steciuk, Hanna; Piasecki, Leszek; Krzepota, Justyna

2014-01-01

319

Monaural and binaural hearing directivity in the bottlenose dolphin: evoked-potential study.  

PubMed

Hearing thresholds as a function of sound-source azimuth were measured in bottlenose dolphins using an auditory evoked potential (AEP) technique. AEP recording from a region next to the ear allowed recording monaural responses. Thus, a monaural directivity diagram (a threshold-vs-azimuth function) was obtained. For comparison, binaural AEP components were recorded from the vertex to get standard binaural directivity diagrams. Both monaural and binaural diagrams were obtained at frequencies ranging from 8 to 128 kHz in quarter-octave steps. At all frequencies, the monaural diagram demonstrated asymmetry manifesting itself as: (1) lower thresholds at the ipsilateral azimuth as compared to the symmetrical contralateral azimuth and (2) ipsilateral shift of the lowest-threshold point. The directivity index increased with frequency: at the ipsilateral side it rose from 4.7 to 17.8 dB from 11.2 to 128 kHz, and from 10.5 to 15.6 dB at the contralateral side. The lowest-threshold azimuth shifted from 0 degrees at 90-128 kHz to 22.5 degrees at 8-11.2 kHz. The frequency-dependent variation of the lowest-threshold azimuth indicates the presence of two sound-receiving apertures at each head side: a high-frequency aperture with the axis directed frontally, and a low-frequency aperture with the axis directed laterally. PMID:16454317

Popov, Vladimir V; Supin, Alexander Ya; Klishin, Vladimir O; Bulgakova, Tatyana N

2006-01-01

320

Behavioral and auditory evoked potential audiograms of a false killer whale (Pseudorca crassidens).  

PubMed

Behavioral and auditory evoked potential (AEP) audiograms of a false killer whale were measured using the same subject and experimental conditions. The objective was to compare and assess the correspondence of auditory thresholds collected by behavioral and electrophysiological techniques. Behavioral audiograms used 3-s pure-tone stimuli from 4 to 45 kHz, and were conducted with a go/no-go modified staircase procedure. AEP audiograms used 20-ms sinusoidally amplitude-modulated tone bursts from 4 to 45 kHz, and the electrophysiological responses were received through gold disc electrodes in rubber suction cups. The behavioral data were reliable and repeatable, with the region of best sensitivity between 16 and 24 kHz and peak sensitivity at 20 kHz. The AEP audiograms produced thresholds that were also consistent over time, with range of best sensitivity from 16 to 22.5 kHz and peak sensitivity at 22.5 kHz. Behavioral thresholds were always lower than AEP thresholds. However, AEP audiograms were completed in a shorter amount of time with minimum participation from the animal. These data indicated that behavioral and AEP techniques can be used successfully and interchangeably to measure cetacean hearing sensitivity. PMID:16266188

Yuen, Michelle M L; Nachtigall, Paul E; Breese, Marlee; Supin, Alexander Ya

2005-10-01

321

Forward-masking based gain control in odontocete biosonar: an evoked-potential study.  

PubMed

Auditory evoked potentials (AEPs) were recorded during echolocation in a false killer whale Pseudorca crassidens. An electronically synthesized and played-back ("phantom") echo was used. Each electronic echo was triggered by an emitted biosonar pulse. The echo had a spectrum similar to that of the emitted biosonar clicks, and its intensity was proportional to that of the emitted click. The attenuation of the echo relative to the emitted click and its delay was controlled by the experimenter. Four combinations of echo attenuation and delay were tested (-31 dB, 2 ms), (-40 dB, 4 ms), (-49 dB, 8 ms), and (-58 dB, 16 ms); thus, attenuation and delay were associated with a rate of 9 dB of increased attenuation per delay doubling. AEPs related to emitted clicks displayed a regular amplitude dependence on the click level. Echo-related AEPs did not feature amplitude dependence on echo attenuation or emitted click levels, except in a few combinations of the lowest values of these two variables. The results are explained by a hypothesis that partial forward masking of the echoes by the preceding emitted sonar pulses serves as a kind of automatic gain control in the auditory system of echolocating odontocetes. PMID:19354417

Supin, Alexander Ya; Nachtigall, Paul E; Breese, Marlee

2009-04-01

322

Fully intact contact heat evoked potentials in patients with amyotrophic lateral sclerosis.  

PubMed

Amyotrophic lateral sclerosis (ALS) is typically considered to be a disease of motor, not sensory, neurons. However, reports exist of sensory system involvement in ALS. In this study we aimed to study the characteristic of contact heat-evoked potentials (CHEPs) in patients with ALS and to evaluate the nociceptive pathway in these patients. Sixty patients with ALS and 60 controls had pain elicited by a CHEP stimulator with an accelerated velocity of 70 degrees C/s. Thermal stimuli were sent at 54.5 degrees C to three body sites: the dorsum of the hand, the proximal volar forearm, and the skin near C7. CHEPs were recorded from Cz and Pz. The onset negative peak latencies were 561.2 +/- 28.6 ms, 540.1 +/- 39.2 ms, and 502.4 +/- 26.2 ms when the dorsum of the hand, the proximal volar forearm, and skin near C7 were stimulated, respectively. There were no significant differences between the ALS patients and the controls with CHEP (P > 0.05). Our results suggest that the nociceptive pathway is intact and support the idea that small fibers and their sensory pathway are spared in ALS. PMID:19260053

Xu, Ying-Sheng; Zhang, Jun; Zheng, Ju-Yang; Zhang, Shuo; Kang, De-Xuan; Fan, Dong-Sheng

2009-06-01

323

Toward brain-computer interface based wheelchair control utilizing tactually-evoked event-related potentials  

PubMed Central

Background People with severe disabilities, e.g. due to neurodegenerative disease, depend on technology that allows for accurate wheelchair control. For those who cannot operate a wheelchair with a joystick, brain-computer interfaces (BCI) may offer a valuable option. Technology depending on visual or auditory input may not be feasible as these modalities are dedicated to processing of environmental stimuli (e.g. recognition of obstacles, ambient noise). Herein we thus validated the feasibility of a BCI based on tactually-evoked event-related potentials (ERP) for wheelchair control. Furthermore, we investigated use of a dynamic stopping method to improve speed of the tactile BCI system. Methods Positions of four tactile stimulators represented navigation directions (left thigh: move left; right thigh: move right; abdomen: move forward; lower neck: move backward) and N?=?15 participants delivered navigation commands by focusing their attention on the desired tactile stimulus in an oddball-paradigm. Results Participants navigated a virtual wheelchair through a building and eleven participants successfully completed the task of reaching 4 checkpoints in the building. The virtual wheelchair was equipped with simulated shared-control sensors (collision avoidance), yet these sensors were rarely needed. Conclusion We conclude that most participants achieved tactile ERP-BCI control sufficient to reliably operate a wheelchair and dynamic stopping was of high value for tactile ERP classification. Finally, this paper discusses feasibility of tactile ERPs for BCI based wheelchair control. PMID:24428900

2014-01-01

324

Extraction of steady state visually evoked potential signal and estimation of distribution map from EEG data.  

PubMed

We propose a signal extraction method from multi-channel EEG signals and apply to extract Steady State Visually Evoked Potential (SSVEP) signal. SSVEP is a response to visual stimuli presented in the form of flushing patterns. By using several flushing patterns with different frequency, brain machine (computer) interface (BMI/BCI) can be realized. Therefore it is important to extract SSVEP signals from multi-channel EEG signals. At first, we estimate the power of the objective signal in each electrode. Estimation of the power is helpful in not only extraction of the signal but also drawing a distribution map of the signal, finding electrodes which have large SNR, and ranking electrodes in sort of information with respect to the power of the signal. Experimental results show that the proposed method 1) estimates more accurate power than existing methods, 2) estimates the global signal which has larger SNR than existing methods, and 3) allows us to draw a distribution map of the signal, and it conforms the biological theory. PMID:18003244

Washizawa, Yoshikazu; Yamashita, Yukihiko; Tanaka, Toshihisa; Cichocki, Andrzej

2007-01-01

325

A Case of Functional (Psychogenic) Monocular Hemianopia Analyzed by Measurement of Hemifield Visual Evoked Potentials  

PubMed Central

Purpose Functional monocular hemianopia is an extremely rare condition, for which measurement of hemifield visual evoked potentials (VEPs) has not been previously described. Methods A 14-year-old boy with functional monocular hemianopia was followed up with Goldmann perimetry and measurement of hemifield and full-field VEPs. Results The patient had a history of monocular temporal hemianopia of the right eye following headache, nausea and ague. There was no relative afferent pupillary defect, and a color perception test was normal. Goldmann perimetry revealed a vertical monocular temporal hemianopia of the right eye; the hemianopia on the right was also detected with a binocular visual field test. Computed tomography, magnetic resonance imaging (MRI) and MR angiography of the brain including the optic chiasm as well as orbital MRI revealed no abnormalities. On the basis of these results, we diagnosed the patient's condition as functional monocular hemianopia. Pattern VEPs according to the International Society for Clinical Electrophysiology of Vision (ISCEV) standard were within the normal range. The hemifield pattern VEPs for the right eye showed a symmetrical latency and amplitude for nasal and temporal hemifield stimulation. One month later, the visual field defect of the patient spontaneously disappeared. Conclusions The latency and amplitude of hemifield VEPs for a patient with functional monocular hemianopia were normal. Measurement of hemifield VEPs may thus provide an objective tool for distinguishing functional hemianopia from hemifield loss caused by an organic lesion. PMID:24474929

Yoneda, Tsuyoshi; Fukuda, Ken; Nishimura, Mayu; Fukushima, Atsuki

2013-01-01

326

Evaluation of new technology for intraoperative evoked compound action potential threshold measurements.  

PubMed

Objective: To determine whether new technology for intraoperative evoked compound action potential (ECAP) threshold measurements-the CR120 Intraoperative Remote Assistant device-is comparable to the existing Custom Sound(®) clinical system, as well as assess test-retest accuracy of the systems. Design: Within subject, repeated measures comparative design. Study sample: ECAP data were collected from 81 pediatric subjects (41 females and 40 males). Results: The average ECAP threshold measurement time for the Custom Sound system was 6.2 minutes (SD = 1.0) versus 4.8 minutes (SD = 0.7) for the CR120 device. ECAP thresholds measured with Custom Sound and the CR120 device had an average Pearson product-moment correlation coefficient for all electrodes (N = 1724) of 0.92, p < 0.01; an average mean absolute difference of 6 CLs (SD = 6); and a 95% confidence interval of - 1 to 1 CLs. The test-retest results for Custom Sound and the CR120 device are also included. Conclusion: A significant reduction in the measurement time for ECAP thresholds was noted with the CR120 device. Furthermore, ECAP thresholds measured with the CR120 device are equivalent to Custom Sound within a clinically acceptable range. PMID:25434429

Tavartkiladze, George; Bakhshinyan, Vigen; Irwin, Colin

2014-12-01

327

Distortion product otoacoustic emissions and auditory evoked potentials in the hedgehog tenrec, Echinops telfairi.  

PubMed

The hedgehog tenrec, Echinops telfairi, has certain basal mammalian features, like a cloaca and a sparsely differentiated brain with smooth cerebral hemispheres. The peripheral auditory capabilities of this species were investigated by means of distortion product otoacoustic emissions (DPOAE). For comparison, we determined auditory evoked potentials (AEP) in the inferior colliculus and the auditory cortex. Both methods show that the auditory range of E. telfairi extends well into ultrasonic frequencies, with a region of highest sensitivity at around 16 kHz. The total auditory range spans about 4 octaves at 40 dB SPL. The low-frequency limit of auditory processing is found at frequencies of about 2-3 kHz. The DPOAE and the AEP thresholds of E. telfairi do not run fully parallel in the high-frequency range. For a threshold value of 40 dB SPL, cochlear mechanical thresholds as measured with DPOAE extend up to 50 kHz, whereas neuronal thresholds reach the high-frequency limit at about 30 kHz. Frequency tuning, as assessed from DPOAE suppression tuning curves, was low to moderate with Q(10 dB) values ranging from 1.7 to 8. The lack of discontinuity in the group delay (derived from DPOAE measurements) reveals that cochlear frequency representation is tonotopic without any region of specialized mechanical tuning. PMID:14569428

Drexl, Markus; Faulstich, Michael; Von Stebut, Boris; Radtke-Schuller, Susanne; Kössl, Manfred

2003-12-01

328

Normative data for vestibular evoked myogenic potential in different age groups among a heterogeneous Indian population.  

PubMed

To establish normative data of vestibular evoked myogenic potential in different age groups among a heterogeneous Indian population. Prospective study design using a sample of convenience. Eighty five normal controls ranging between the ages 7 and 71 years were asked to provide a written signed consent for the study. Demographic characteristics of the patients were summarized using descriptive statistical methods using SPSS-17 analysing software. The outcome variable (VEMP recording) was expressed in percentiles as function of age. In all patients the stimulus which gave the best response was 95 dB (97.7 %) and 100 dB (95 %). The mean of wave latencies (p1 & n1) for 95-VEMP were, 11.2 ± 3.2 and 17.3 ± 4.7 ms on the right and 11.0 ± 2.8 and 17.0 ± 4.2 ms on the left respectively. The amplitude was 45.1 ± 54 mV on right and 46.9 ± 61.6 mV on the left. The mean of latency difference was 0.87 ms. The VEMP is a relatively simple test. The VEMP response rate was maximum in the younger age group; the optimum intensity was 95 dB. The asymmetry ratio interpretation should be done according to the age specific values. PMID:24822153

Khan, Feroze K; Balraj, Achamma; Lepcha, Anjali

2014-06-01

329

Visuocortical Changes During Delay and Trace Aversive Conditioning: Evidence From Steady-State Visual Evoked Potentials  

PubMed Central

The visual system is biased towards sensory cues that have been associated with danger or harm through temporal co-occurrence. An outstanding question about conditioning-induced changes in visuocortical processing is the extent to which they are driven primarily by top-down factors such as expectancy or by low-level factors such as the temporal proximity between conditioned stimuli and aversive outcomes. Here, we examined this question using two different differential aversive conditioning experiments: participants learned to associate a particular grating stimulus with an aversive noise that was presented either in close temporal proximity (delay conditioning experiment) or after a prolonged stimulus-free interval (trace conditioning experiment). In both experiments we probed cue-related cortical responses by recording steady-state visual evoked potentials (ssVEPs). Although behavioral ratings indicated that all participants successfully learned to discriminate between the grating patterns that predicted the presence versus absence of the aversive noise, selective amplification of population-level responses in visual cortex for the conditioned danger signal was observed only when the grating and the noise were temporally contiguous. Our findings are in line with notions purporting that changes in the electrocortical response of visual neurons induced by aversive conditioning are a product of Hebbian associations among sensory cell assemblies rather than being driven entirely by expectancy-based, declarative processes. PMID:23398582

Miskovic, Vladimir; Keil, Andreas

2015-01-01

330

Instrumentation to Record Evoked Potentials for Closed-Loop Control of Deep Brain Stimulation  

PubMed Central

Closed-loop deep brain stimulation (DBS) systems offer promise in relieving the clinical burden of stimulus parameter selection and improving treatment outcomes. In such a system, a feedback signal is used to adjust automatically stimulation parameters and optimize the efficacy of stimulation. We explored the feasibility of recording electrically evoked compound action potentials (ECAPs) during DBS for use as a feedback control signal. A novel instrumentation system was developed to suppress the stimulus artifact and amplify the small magnitude, short latency ECAP response during DBS with clinically relevant parameters. In vitro testing demonstrated the capabilities to increase the gain by a factor of 1,000x over a conventional amplifier without saturation, reduce distortion of mock ECAP signals, and make high fidelity recordings of mock ECAPs at latencies of only 0.5 ms following DBS pulses of 50 to 100 ?s duration. Subsequently, the instrumentation was used to make in vivo recordings of ECAPs during thalamic DBS in cats, without contamination by the stimulus artifact. The signal characteristics were similar across three experiments, suggesting common neural activation patterns. The ECAP recordings enabled with this novel instrumentation may provide insight into the type and spatial extent of neural elements activated during DBS, and could serve as feedback control signals for closed-loop systems. PMID:22255894

Kent, Alexander R.; Grill, Warren M.

2012-01-01

331

Spinal cord monitoring during spinal surgery using somatosensory spinal evoked potentials.  

PubMed

Intraoperative monitoring of spinal cord function has been carried out in 59 patients during spinal instrumentation for scoliosis. Posterior tibial nerve stimulation in the popliteal space was performed and spinal evoked potentials from electrodes in the spinous processes observed. A rod artifact problem causing partial obliteration of the wave form can be minimized or eliminated by careful selection of the insertion of the fixation device. A drop in amplitude of the signal occurred in many of the tracings from control to distraction observations but did not result in neurologic deficit. One patient had a loss of the signal after maximum distraction with a Harrington rod and a return with release of distraction. This patient awoke with paralytic urinary bladder retention which resolved spontaneously but no other neurologic deficit. This method has been used for monitoring of spinal cord function during Harrington rod instrumentation, using both compression and distraction systems as well as Luque rod instrumentation. This method is safe, simple, and provides consistent and predictable wave forms; it appears to be reliable in indicating continuation of spinal cord function during the procedure. PMID:6841600

LaMont, R L; Wasson, S L; Green, M A

1983-02-01

332

The use of QSD (q-sequence deconvolution) to recover superposed, transient evoked-responses  

E-print Network

was applied to recordings of the human auditory brainstem response (ABR) at stimulus repetition; Superposition; Quasi-periodic; Auditory brainstem response; Evoked-responses; Stimulus rate; Overlapped of the auditory brainstem response (ABR), ".increasing rate of stimulation facilitates the identification of [ABR

Larson-Prior, Linda

333

Maximal twitch tension in intact length-clamped ferret papillary muscles evoked by modified postextrasystolic potentiation.  

PubMed

A modified test of postextrasystolic potentiation achieved with a brief episode of rapid pacing followed by a 6-second pause (RPP maneuver) was used to evoke maximal force in isolated intact ferret right ventricular papillary muscles. Maximal RPP tensions were examined under length-clamped conditions and compared with the steady-state forces obtained when further increases in [Ca2+]o, did not further increase force and to the tensions recorded at the point of saturation of force when similarly length-clamped muscles were subjected to caffeine-induced tetanization. The results show that the calculated maximal twitch tension achieved with RPP is comparable to the 25-35 g/mm2 observed in intact single skeletal muscle fibers. The study also shows that the beat-to-beat decay of the potentiated contraction is exponential. While the amount of the constant fractional beat-to-beat decay is a function of [Ca2+]o, it is not influenced by length. During the decay of potentiation, the ratio of the potentiation of any beat divided by that of the previous beat is a constant, called (X). With certain assumptions, it is shown that (X) is a measure of the fraction of activator calcium taken up by the sarcoplasmic reticulum in each beat and, in the steady state, the fraction of activator calcium that comes from the sarcoplasmic reticulum. The (X) amounted to 33%, 50%, and 65% when [Ca2+]o was 1.25, 2.50, and 5.0 mM, respectively. Thus, at 1.25 mM [Ca2+]o, some two thirds of the total calcium required to activate the myofilaments comes from the extracellular compartment during excitation and only one third is contributed via release from the sarcoplasmic reticulum. In the region of optimal myofilament overlap, RPP force-length curves are remarkably shallow and almost indistinguishable from the sarcomere length-tension relation observed in skinned single cardiac cells. Tetanus plateau tensions are significantly smaller than RPP forces at any length, and the slope of the tetanus force-length curves is greater than that obtained with RPP. Thus, and by exclusion, we also suggest that caffeine may exert significant downstream inhibitory effects. PMID:3335058

Urthaler, F; Walker, A A; Reeves, D N; Hefner, L L

1988-01-01

334

Intraoperative monitoring of somatosensory-evoked potential in the spinal cord rectification operation by means of wavelet analysis  

NASA Astrophysics Data System (ADS)

Recently there has been a considerable interest in the use of a somatosensory evoked potential (SEP) for monitoring the functional integrity of the spinal cord during surgery such as spinal scoliosis. This paper describes a monitoring system and signal processing algorithms, which consists of 50 Hz mains filtering and a wavelet signal analyzer. Our system allows fast detection of changes in SEP peak latency, amplitude and signal waveform, which are the main parameters of interest during intra-operative procedures.

Liu, W.; Du, M. H.; Chan, Francis H. Y.; Lam, F. K.; Luk, D. K.; Hu, Y.; Fung, Kan S. M.; Qiu, W.

1998-09-01

335

Scalp topography and dipolar source modelling of potentials evoked by CO 2 laser stimulation of the hand  

Microsoft Academic Search

CO2 laser evoked potentials to hand stimulation recorded using a scalp 19-channel montage in 11 normal subjects consistently showed early N1\\/P1 dipolar field distribution peaking at a mean latency of 159 ms. The N1 negativity was distributed in the temporoparietal region contralateral to stimulation and the P1 positivity in the frontal region. The N1\\/P1 response was followed by 3 distinct

Massimiliano Valeriani; Loic Rambaud; François Mauguière

1996-01-01

336

MRI of optic nerve and postchiasmal visual pathways and visual evoked potentials in secondary progressive multiple sclerosis  

Microsoft Academic Search

We studied the relationship between abnormalities shown by MRI and functional disturbances in the visual pathway as assessed\\u000a by the visual evoked potential (VEP) in 25 patients with established multiple sclerosis (MS); only 4 of whom had a history\\u000a of acute optic neuritis. Optic nerve MRI was abnormal in 19 (76 %) and is thus useful in detecting subclinical disease.

M. B. Davies; R. Williams; N. Haq; L. Pelosi; C. P. Hawkins

1998-01-01

337

Attenuation of N2 amplitude of laser-evoked potentials by theta burst stimulation of primary somatosensory cortex  

Microsoft Academic Search

Theta burst stimulation (TBS) is a special repetitive transcranial magnetic stimulation (rTMS) paradigm, where bursts of low-intensity\\u000a stimuli are applied in the theta frequency. The aim of this study was to investigate the effect of neuronavigated TBS over\\u000a primary somatosensory cortex (SI) on laser-evoked potentials (LEPs) and acute pain perception induced with Tm : YAG laser\\u000a stimulation. The amplitude changes of the

Csaba Poreisz; Andrea Antal; Klára Boros; Nadine Brepohl; Gábor Csifcsák; Walter Paulus

2008-01-01

338

Effects of electrical water bath stunning current frequencies on the spontaneous electroencephalogram and somatosensory evoked potentials in hens  

Microsoft Academic Search

1. The effectiveness of water bath electrical stunning of chickens with a constant root mean square (rms) current of 100?mA per bird delivered for 3?s using 100, 200, 400, 800 and 1500?Hz sine wave alternating current (AC) was investigated in layer hens. The quantitative changes occurring in the electroencephalogram (EEG) and somatosensory evoked potentials (SEPs) were used to determine the

A. B. M. Raj; M. O’Callaghan

2004-01-01

339

Partial Recovery of Alcohol Dependence-Related Deficits in Sleep Evoked Potentials Following 12?Months of Abstinence  

PubMed Central

Stimuli presented during sleep can produce an evoked EEG delta wave referred to as a K-complex. These responses occur when large numbers of cortical cells burst fire in a synchronized manner. Large amplitude synchronized scalp responses require that the CNS contain large numbers of healthy neurons that are interconnected with highly functional white matter pathways. The P2, N550, and P900 components of the evoked K-complex are sensitive measures of normal healthy brain aging, showing a decrease in amplitude with age. N550 and P900 amplitudes are also reduced in recently detoxified alcoholics, most dramatically over frontal scalp regions. The present study tested the hypothesis that the amplitude of K-complex related evoked potential components would increase with prolonged abstinence. Fifteen alcoholics (12 men) were studied twice, separated by a 12?month period, during which time they were followed with monthly phone calls. Subjects were aged between 38 and 60?years at their first study. They had on average a 29.3?±?6.7?year drinking history and had been abstinent for between 54 and 405?days at initial testing. Evoked K-complexes were identified in the EEG and averaged to enable measurement of the P2, N550 and P900 peaks. Data were collected from seven scalp sites (FP1, FP2, Fz, FCz, Cz, CPz, and Pz). N550 and P900 amplitudes were significantly higher after 12?months of abstinence and an improvement of at least 5??V occurred in 12 of the 15 subjects. N550 and P900 also showed highly significant site by night interactions with the largest increases occurring over prefrontal and frontal sites. The data indicate that the sleep evoked response may provide a sensitive marker of brain recovery with abstinence from alcohol. PMID:22438848

Colrain, Ian M.; Padilla, Mayra L.; Baker, Fiona C.

2011-01-01

340

The effects of prenatal exposure to buprenorphine or methadone on infant visual evoked potentials.  

PubMed

This study compared the neurological development of 4 month old infants exposed to buprenorphine or methadone during pregnancy to that of a control group of non-exposed infants. Participants were 30 buprenorphine-maintained women, 22 methadone-maintained women and 33 non opioid-dependent controls, and their infants. Women were enrolled during pregnancy as part of an open-label non-randomised flexible-dosing longitudinal study. Groups were matched for maternal age, parity, gravida, and tobacco and alcohol use. Infant neurological development was assessed by measuring latency of pattern reversal visual evoked potentials (VEP). One-way between groups analyses of variance (ANOVA) were conducted to test the statistical significance of differences between the mean latencies of the peak response to two different sized checkerboard patterns (48' and 69' of retinal arc). Infants prenatally exposed to methadone had significantly prolonged latencies, compared with infants in the control group and infants prenatally exposed to buprenorphine, in response to checks of 48' and 69'. VEP latencies of infants prenatally exposed to buprenorphine did not differ significantly from controls for either check size. After adjustment for covariates, prenatal exposure to methadone remained a significant predictor of VEP response to checks of 48', but not 69'. Maternal self-reported used of marijuana during pregnancy made a significant unique contribution to the variance in P1 latencies for both check sizes. Data from this controlled, non-randomised study suggest that buprenorphine may confer an advantage over methadone as a maintenance drug during pregnancy in terms of infant neural development at 4 months of age. PMID:19751825

Whitham, Justine N; Spurrier, Nicola J; Sawyer, Michael G; Baghurst, Peter A; Taplin, John E; White, Jason M; Gordon, Andrea L

2010-01-01

341

Steady-state sweep visual evoked potential processing denoised by wavelet transform  

NASA Astrophysics Data System (ADS)

Visually evoked potential (VEP) is a very small electrical signal originated in the visual cortex in response to periodic visual stimulation. Sweep-VEP is a modified VEP procedure used to measure grating visual acuity in non-verbal and preverbal patients. This biopotential is buried in a large amount of electroencephalographic (EEG) noise and movement related artifact. The signal-to-noise ratio (SNR) plays a dominant role in determining both systematic and statistic errors. The purpose of this study is to present a method based on wavelet transform technique for filtering and extracting steady-state sweep-VEP. Counter-phase sine-wave luminance gratings modulated at 6 Hz were used as stimuli to determine sweep-VEP grating acuity thresholds. The amplitude and phase of the second-harmonic (12 Hz) pattern reversal response were analyzed using the fast Fourier transform after the wavelet filtering. The wavelet transform method was used to decompose the VEP signal into wavelet coefficients by a discrete wavelet analysis to determine which coefficients yield significant activity at the corresponding frequency. In a subsequent step only significant coefficients were considered and the remaining was set to zero allowing a reconstruction of the VEP signal. This procedure resulted in filtering out other frequencies that were considered noise. Numerical simulations and analyses of human VEP data showed that this method has provided higher SNR when compared with the classical recursive least squares (RLS) method. An additional advantage was a more appropriate phase analysis showing more realistic second-harmonic amplitude value during phase brake.

Weiderpass, Heinar A.; Yamamoto, Jorge F.; Salomão, Solange R.; Berezovsky, Adriana; Pereira, Josenilson M.; Sacai, Paula Y.; de Oliveira, José P.; Costa, Marcio A.; Burattini, Marcelo N.

2008-03-01

342

Contact heat-evoked potentials as a useful means in patients with Guillain-Barré syndrome.  

PubMed

Few objective methods have been utilized to identify the small myelinated fiber impairment causing neuropathic pain in Guillain-Barré syndrome (GBS). In this study, contact heat-evoked potentials (CHEPs) were applied to study the nociceptive pathway in GBS. Sixty GBS patients and fifty healthy controls were enrolled. The 60 GBS patients were divided into two subgroups presenting with or without subjective lower limb paresthesia (21/39). CHEPs were recorded at Cz and Pz with a peak thermal stimuli of 47 °C applied to the skin of the leg above the internal malleolus (AIM) and of the waist at the anterior superior iliac spine (ASIS) level. The N2 latency and N2-P2 amplitude of CHEPs were compared. When the skin of the leg AIM was stimulated, the N2 latency was significantly postponed (425.23 ± 28.66 vs. 402.30 ± 19.48 ms, P < 0.05) and the N2-P2 amplitude significantly decreased in GBS patients as compared to controls (32.71 ± 7.49 vs. 42.77 ± 8.71 ?V, P < 0.05). Slower nerve conduction velocity was observed in GBS patients (11.84 ± 1.45 vs. 13.28 ± 0.66 ms, P < 0.05). However, no differences in N2 latency or N2-P2 amplitude were detected between the two subgroups of GBS patients with or without subjective lower limb paresthesia (P all >0.05). Moreover, there were no differences in N2 latency and N2-P2 amplitude among different groups when the waist was stimulated at the ASIS level. Our study suggested that CHEPs could be utilized as an objective and non-invasive tool to detect small myelinated fiber damage in GBS patients, especially for those without subjective paresthesia. PMID:24584633

Zhang, Chao; Xie, Bingdi; Li, Xiaowen; Yao, Yuanrong

2014-08-01

343

Multifocal visual evoked potential in optic neuritis, ischemic optic neuropathy and compressive optic neuropathy  

PubMed Central

Purpose: To investigate the effect of optic neuritis (ON), ischemic optic neuropathy (ION) and compressive optic neuropathy (CON) on multifocal visual evoked potential (mfVEP) amplitudes and latencies, and to compare the parameters among three optic nerve disorders. Materials and Methods: mfVEP was recorded for 71 eyes of controls and 48 eyes of optic nerve disorders with subgroups of optic neuritis (ON, n = 21 eyes), ischemic optic neuropathy (ION, n = 14 eyes), and compressive optic neuropathy (CON, n = 13 eyes). The size of defect in mfVEP amplitude probability plots and relative latency plots were analyzed. The pattern of the defect in amplitude probability plot was classified according to the visual field profile of optic neuritis treatment trail (ONTT). Results: Median of mfVEP amplitude (log SNR) averaged across 60 sectors were reduced in ON (0.17 (0.13-0.33)), ION (0.14 (0.12-0.21)) and CON (0.21 (0.14-0.30)) when compared to controls. The median mfVEP relative latencies compared to controls were significantly prolonged in ON and CON group of 10.53 (2.62-15.50) ms and 5.73 (2.67-14.14) ms respectively compared to ION group (2.06 (-4.09-13.02)). The common mfVEP amplitude defects observed in probability plots were diffuse pattern in ON, inferior altitudinal defect in ION and temporal hemianopia in CON eyes. Conclusions: Optic nerve disorders cause reduction in mfVEP amplitudes. The extent of delayed latency noted in ischemic optic neuropathy was significantly lesser compared to subjects with optic neuritis and compressive optic neuropathy. mfVEP amplitudes can be used to objectively assess the topography of the visual field defect. PMID:24088641

Jayaraman, Manju; Gandhi, Rashmin Anilkumar; Ravi, Priya; Sen, Parveen

2014-01-01

344

Emotional modulation of experimental pain: a source imaging study of laser evoked potentials  

PubMed Central

Negative emotions have been shown to augment experimental pain. As induced emotions alter brain activity, it is not clear whether pain augmentation during noxious stimulation would be related to neural activation existing prior to onset of a noxious stimulus or alternatively, whether emotional stimuli would only alter neural activity during the period of nociceptive processing. We analyzed the spatio-temporal patterns of laser evoked potentials (LEPs) occurring prior to and during the period of cortical processing of noxious laser stimuli during passive viewing of negative, positive, or neutral emotional pictures. Independent component analysis (ICA) was applied to series of source activation volumes, reconstructed using local autoregressive average model (LAURA). Pain was the strongest when laser stimuli were associated with negative emotional pictures. Prior to laser stimulus and during the first 100 ms after onset of laser stimulus, activations were seen in the left and right medial temporal cortex, cerebellum, posterior cingulate, and rostral cingulate/prefrontal cortex. In all these regions, positive or neutral pictures showed stronger activations than negative pictures. During laser stimulation, activations in the right and left anterior insula, temporal cortex and right anterior and posterior parietal cortex were stronger during negative than neutral or positive emotional pictures. Results suggest that negative emotional stimuli increase activation in the left and right anterior insula and temporal cortex, and right posterior and anterior parietal cortex only during the period of nociceptive processing. The role of background brain activation in emotional modulation of pain appears to be only permissive, and consisting in attenuation of activation in structures maintaining the resting state of the brain. PMID:24062659

Stancak, Andrej; Fallon, Nicholas

2013-01-01

345

Visual Evoked Cortical Potential (VECP) Elicited by Sinusoidal Gratings Controlled by Pseudo-Random Stimulation  

PubMed Central

The contributions of contrast detection mechanisms to the visual cortical evoked potential (VECP) have been investigated studying the contrast-response and spatial frequency-response functions. Previously, the use of m-sequences for stimulus control has been almost restricted to multifocal electrophysiology stimulation and, in some aspects, it substantially differs from conventional VECPs. Single stimulation with spatial contrast temporally controlled by m-sequences has not been extensively tested or compared to multifocal techniques. Our purpose was to evaluate the influence of spatial frequency and contrast of sinusoidal gratings on the VECP elicited by pseudo-random stimulation. Nine normal subjects were stimulated by achromatic sinusoidal gratings driven by pseudo random binary m-sequence at seven spatial frequencies (0.4–10 cpd) and three stimulus sizes (4°, 8°, and 16° of visual angle). At 8° subtence, six contrast levels were used (3.12–99%). The first order kernel (K1) did not provide a consistent measurable signal across spatial frequencies and contrasts that were tested–signal was very small or absent–while the second order kernel first (K2.1) and second (K2.2) slices exhibited reliable responses for the stimulus range. The main differences between results obtained with the K2.1 and K2.2 were in the contrast gain as measured in the amplitude versus contrast and amplitude versus spatial frequency functions. The results indicated that K2.1 was dominated by M-pathway, but for some stimulus condition some P-pathway contribution could be found, while the second slice reflected the P-pathway contribution. The present work extended previous findings of the visual pathways contribution to VECP elicited by pseudorandom stimulation for a wider range of spatial frequencies. PMID:23940546

Araújo, Carolina S.; Souza, Givago S.; Gomes, Bruno D.; Silveira, Luiz Carlos L.

2013-01-01

346

Short latency vestibular evoked potentials in the Japanese quail (Coturnix coturnix japonica)  

NASA Technical Reports Server (NTRS)

Short-latency vestibular-evoked potentials to pulsed linear acceleration were characterized in the quail. Responses occurred within 8 ms following the onset of stimuli and were composed of a series of positive and negative peaks. The latencies and amplitudes of the first four peaks were quantitatively characterized. Mean latencies at 1.0 g ms-1 ranged from 1265 +/- 208 microseconds (P1, N = 18) to 4802 +/- 441 microseconds (N4, N = 13). Amplitudes ranged from 3.72 +/- 1.51 microV (P1/N1, N = 18) to 1.49 +/- 0.77 microV (P3/N3, N = 16). Latency-intensity (LI) slopes ranged from -38.7 +/- 7.3 microseconds dB-1 (P1, N = 18) to -71.6 +/- 21.9 microseconds dB-1 (N3, N = 15) and amplitude-intensity (AI) slopes ranged from 0.20 +/- 0.08 microV dB-1 (P1/N1, N = 18) to 0.07 +/- 0.04 microV dB-1 (P3/N3, N = 11). The mean response threshold across all animals was -21.83 +/- 3.34 dB re: 1.0 g ms-1 (N = 18). Responses remained after cochlear extirpation showing that they could not depend critically on cochlear activity. Responses were eliminated by destruction of the vestibular end organs, thus showing that responses depended critically and specifically on the vestibular system. The results demonstrate that the responses are vestibular and the findings provide a scientific basis for using vestibular responses to evaluate vestibular function through ontogeny and senescence in the quail.

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

1997-01-01

347

Effect of nitric oxide on spinal evoked potentials and survival rate in rats with decompression sickness.  

PubMed

Nitric oxide (NO) releasing agents have, in experimental settings, been shown to decrease intravascular nitrogen bubble formation and to increase the survival rate during decompression sickness (DCS) from diving. The effect has been ascribed to a possible removal of preexisting micronuclei or an increased nitrogen washout on decompression through augmented blood flow rate. The present experiments were conducted to investigate whether a short- or long-acting NO donor [glycerol trinitrate (GTN) or isosorbide-5-mononitrate (ISMN), respectively] would offer the same protection against spinal cord DCS evaluated by means of spinal evoked potentials (SEPs). Anesthetized rats were decompressed from a 1-h hyperbaric air dive at 506.6 kPa (40 m of seawater) for 3 min and 17 s, and spinal cord conduction was studied by measurements of SEPs. Histological samples of the spinal cord were analyzed for lesions of DCS. In total, 58 rats were divided into 6 different treatment groups. The first three received either saline (group 1), 300 mg/kg iv ISMN (group 2), or 10 mg/kg ip GTN (group 3) before compression. The last three received either 300 mg/kg iv ISMN (group 4), 1 mg/kg iv GTN (group 5), or 75 ?g/kg iv GTN (group 6) during the dive, before decompression. In all groups, decompression caused considerable intravascular bubble formation. The ISMN groups showed no difference compared with the control group, whereas the GTN groups showed a tendency toward faster SEP disappearance and shorter survival times. In conclusion, neither a short- nor long-acting NO donor had any protective effect against fatal DCS by intravenous bubble formation. This effect is most likely due to a fast ascent rate overriding the protective effects of NO, rather than the total inert tissue gas load. PMID:25377881

Randsoe, T; Meehan, C F; Broholm, H; Hyldegaard, O

2015-01-01

348

Time Jitter of Somatosensory Evoked Potentials in Recovery from Hypoxic-ischemic Brain Injury  

PubMed Central

Impaired neural conductivity shown by delayed latency and reduced amplitude of characteristic peaks in somatosensory evoked potentials (SSEPs), has been used to monitor hypoxic-ischemic brain injury after Cardiac Arrest (CA). However, rather than characteristic peak deferral and suppression, the time jitter of the peak in SSEP related with time-variant neurological abnormalities is diminished by the commonly used ensemble average method. This paper utilizes the second order blind identification (SOBI) technique to extract characteristic peak information from one trial of SSEPs. Sixteen male Wistar rats were subjected to 7 or 9 minutes of asphyxial CA (n=8 per group). The SSEPs from median nerve stimulation were recorded for 4 hours after CA and then for 15 minute periods at 24, 48 and 72 h. Neurological outcomes were evaluated by Neurologic Deficit Score (NDS) at 72h post-CA. The SSEP signal was analyzed offline with SOBI processing in Matlab. The N10 feature of SSEP was compared between good (NDS?50) and bad (NDS<50) outcomes. After processed by SOBI, the N10 detection rate was significantly increased (p<0.001) from 90 min post-CA. Statistical difference of the latency variance of the N10 between good and bad outcome groups existed at 24, 48 and 72 h post-CA (p<=0.001). Our study is the first application using SOBI detecting variance in neural signals like SSEP. N10 latency variance, related with neurophysiological dysfunction, increased after hypoxic-ischemic injury. The SOBI technique is an efficient method in the identification of peak detection and offers a favorable alternative to reveal the neural transmission variation. PMID:21878352

Ma, Ying; Hu, Yong; Valentin, Nicolas; Geocadin, Romergryko G; Thakor, Nitish V; Jia, Xiaofeng

2011-01-01

349

The use of contact heat evoked potential stimulator (CHEPS) in magnetoencephalography for pain research  

PubMed Central

Background Contact heat evoked potentials (CHEP) is a thermal stimulus modality used in pain research. We examine a commercial CHEP stimulator (CHEPS) that is designed to work in an fMRI environment, but poorly understood in the MEG environment. The CHEPS attains target temperatures rapidly using sophisticated control signals that unfortunately induce artifacts in the MEG. In this paper, we summarize our experiences using the CHEPS in MEG to study pain using an experimental paradigm, and propose a novel method for managing its artifact. New method We introduce a novel damped sinusoid modeling (DSM) technique to remove the CHEPS artifact based on estimates of the underlying sinusoids and damping factors. We show comparisons to signal space projection (SSP) and temporal signal space separation (tSSS) methods. Results The CHEPS artifact is highly dynamic, yet deterministic, switching rapidly from one frequency to another, with different spatial components. The galvanic connection between the subject and the CHEPS probe alters its performance, making pre-characterization difficult. Comparison with existing methods SSP methods failed to remove the artifact completely. TSSS performed better than SSP; however, tSSS requires the use of a multipolar head model that decreases the dimensionality and possibly the information content of the data. In contrast, DSM offers a strictly temporal modeling approach in which the artifact is estimated as a sum of damped sinusoids which is subtracted from the data. Conclusion Though the CHEPS increases the noise floor and introduces artifacts to the data, we believe the device can be successfully used in MEG if appropriate artifact removal techniques are followed. PMID:23994044

Gopalakrishnan, Raghavan; Machado, Andre G.; Burgess, Richard C.; Mosher, John C.

2013-01-01

350

Effect of sevoflurane concentration on visual evoked potentials with pattern stimulation in dogs.  

PubMed

The purpose of this study was to investigate the effects of sevoflurane concentration on canine visual evoked potentials with pattern stimulation (P-VEPs). Six clinically normal laboratory-beagle dogs were used. The minimum alveolar concentration (MAC) of sevoflurane was detected from all subjects by tail clamp method. The refractive power of the right eyes of all subjects was corrected to -2 diopters after skiascopy. For P-VEP recording, the recording and reference electrode were positioned at inion and nasion, respectively, and the earth electrode was positioned on the inner surface. To grasp the state of CNS suppression objectively, the bispectral index (BIS) value was used. The stimulus pattern size and distance for VEP recording were constant, 50.3 arc-min and 50 cm, respectively. P-VEPs and BIS values were recorded under sevoflurane in oxygen inhalational anesthesia at 0.5, 1.0, 1.5, 2.0, 2.5 and 2.75 sevoflurane MAC. For analysis of P-VEP, the P100 implicit time and N75-P100 amplitude were estimated. P-VEPs were detected at 0.5 to 1.5 MAC in all dogs, and disappeared at 2.0 MAC in four dogs and at 2.5 and 2.75 MAC in one dog each. The BIS value decreased with increasing sevoflurane MAC, and burst suppression began to appear from 1.5 MAC. There was no significant change in P100 implicit time and N75-P100 amplitude with any concentration of sevoflurane. At concentrations around 1.5 MAC, which are used routinely to immobilize dogs, sevoflurane showed no effect on P-VEP. PMID:25373729

Ito, Yosuke; Maehara, Seiya; Itoh, Yoshiki; Hayashi, Miri; Kubo, Akira; Itami, Takaharu; Ishizuka, Tomohito; Tamura, Jun; Yamashita, Kazuto

2014-11-01

351

Difference of Diagnostic Rates and Analytical Methods in the Test Positions of Vestibular Evoked Myogenic Potentials  

PubMed Central

Objective To compare the differences of diagnostic rates, of the two widely used test positions, in measuring vestibular evoked myogenic potentials (VEMP) and selecting the most appropriate analytical method for diagnostic criteria for the patients with vertigo. Methods Thirty-two patients with vertigo were tested in two comparative testing positions: turning the head to the opposite side of the evaluating side and bowing while in seated position, and bowing while in supine positions. Abnormalities were determined by prolonged latency of p13 or n23, shortening of the interpeak latency, and absence of VEMP formation. Results Using the three criteria above for determining abnormalities, both the seated and supine positions showed no significant differences in diagnostic rates, however, the concordance correlation of the two positions was low. When using only the prolonged latency of p13 or n23 in the two positions, diagnostic rates were not significantly different and their concordance correlation was high. On the other hand, using only the shortened interpeak latency in both positions showed no significant difference of diagnostic rates, and the degree of agreement between two positions was low. Conclusion Bowing while in seated position with the head turned in the opposite direction to the area being evaluated is found to be the best VEMP test position due to the consistent level of sternocleidomastoid muscle tension and the high level of compliance. Also, among other diagnostic analysis methods, using prolonged latency of p13 or n23 as the criterion is found to be the most appropriate method of analysis for the VEMP test. PMID:24855617

Park, Jeong Mee; Yong, Sang Yeol; Kim, Jong Heon; Kim, Hee; Park, Sang-Yoo

2014-01-01

352

The Effect of Acute Sleep Deprivation on Visual Evoked Potentials in Professional Drivers  

PubMed Central

Study Objectives: Previous studies have demonstrated that as little as 18 hours of sleep deprivation can cause deleterious effects on performance. It has also been suggested that sleep deprivation can cause a “tunnel-vision” effect, in which attention is restricted to the center of the visual field. The current study aimed to replicate these behavioral effects and to examine the electrophysiological underpinnings of these changes. Design: Repeated-measures experimental study. Setting: University laboratory. Patients or Participants: Nineteen professional drivers (1 woman; mean age = 45.3 ± 9.1 years). Interventions: Two experimental sessions were performed; one following 27 hours of sleep deprivation and the other following a normal night of sleep, with control for circadian effects. Measurements & Results: A tunnel-vision task (central versus peripheral visual discrimination) and a standard checkerboard-viewing task were performed while 32-channel EEG was recorded. For the tunnel-vision task, sleep deprivation resulted in an overall slowing of reaction times and increased errors of omission for both peripheral and foveal stimuli (P < 0.05). These changes were related to reduced P300 amplitude (indexing cognitive processing) but not measures of early visual processing. No evidence was found for an interaction effect between sleep deprivation and visual-field position, either in terms of behavior or electrophysiological responses. Slower processing of the sustained parvocellular visual pathway was demonstrated. Conclusions: These findings suggest that performance deficits on visual tasks during sleep deprivation are due to higher cognitive processes rather than early visual processing. Sleep deprivation may differentially impair processing of more-detailed visual information. Features of the study design (eg, visual angle, duration of sleep deprivation) may influence whether peripheral visual-field neglect occurs. Citation: Jackson ML; Croft RJ; Owens K; Pierce RJ; Kennedy GA; Crewther D; Howard ME. The effect of acute sleep deprivation on visual evoked potentials in professional drivers. SLEEP 2008;31(9):1261-1269. PMID:18788651

Jackson, Melinda L.; Croft, Rodney J.; Owens, Katherine; Pierce, Robert J.; Kennedy, Gerard A.; Crewther, David; Howard, Mark E.

2008-01-01

353

Temporal resolution in the dolphin's auditory system revealed by double-click evoked potential study.  

PubMed

Temporal resolution of hearing in two bottlenosed dolphins was estimated by measuring auditory brain-stem response (ABR) recovery in conditions of double-click stimuli. From these data, temporal transfer function of the supposed integrator was derived assuming nonlinear transform of the integrator output to ABR amplitude. The obtained temporal transfer function showed a nearly constant level up to 200 microseconds. then decay to approximately -3 dB at 300 microseconds (as presented in the sound intensity domain), and subsequent decay of 10-11 dB per time doubling (about 35 dB/decade). PMID:7598764

Supin AYa; Popov, V V

1995-04-01

354

[The diagnosis of amyotrophic lateral sclerosis supported by motor evoked potential and brain MRI studies].  

PubMed

A 57-year-old man developed severe muscle weakness and atrophy of the upper extremities within a five-month period. Neurological examination revealed severe weakness and atrophy in the scapular muscles and proximal and distal muscles of the upper extremities. Fasciculations were also observed in the various muscles of the upper extremities. There was neither muscle weakness, atrophy nor fasciculation in either his face, neck muscles or lower extremities. He had no pseudobulbar or bulbar signs. Tendon reflexes were mildly hyperactive in the jaw and lower extremities, and normal in the upper extremities. There were no pathological reflexes, spasticity or sensory disturbances. The needle EMG study revealed denervation potentials in all muscles of the upper extremities examined. The nerve conduction study revealed no findings of the conduction block. Cervical spine X-rays revealed the narrowing of the spinal foramens at the left C3/C4 and bilateral C4/C5, C5/C6, and C6/C7 intervertebral levels. In addition, magnetic resonance imaging (MRI) revealed compressions of the cervical cord at C4/C5 and C5/C6 intervertebral levels. These clinical and neuroradiological findings resembled those of the cervical spondylotic amyotrophy (CSA). However, the motor evoked potential (MEP) study revealed the pyramidal tract dysfunction above the levels of the pyramidal decussation. Furthermore, brain MRI revealed abnormal foci in both internal capsules which were characterized by hyperintense relative to cortical gray matter on T2-weighted images and still hyperintense to white matter on proton-density-weighted images. In addition, T2-weighted images demonstrated a low signal within the motor cortex and hyperintense lesions in the white matter of the precentral gyri. These MRI findings indicated the degeneration of the pyramidal tract and corresponded to those found in the patients with amyotrophic lateral sclerosis (ALS) which have been recently reported. It has been difficult to distinguish ALS from CSA. However, MEP and brain MRI studies were useful for distinguishing these two diseases in this patient. In addition, this patient showed typical MRI findings suggesting the degeneration of the pyramidal tract, although this patient had a relatively short course of illness and did not show obvious physical findings suggesting pyramidal tract dysfunction. PMID:9217423

Matsunaga, K; Iwamoto, M; Tsuji, S; Hashimoto, T; Murai, Y

1997-03-01

355

CHLORDIMEFORM PRODUCES PROFOUND, SELECTIVE, AND TRANSIENT CHANGES IN VISUAL EVOKED POTENTIALS OF HOODED RATS  

EPA Science Inventory

Rat visual function was tested after acute exposure to chlordimeform (CDM), a formamidine insecticide/acaricide. Adult male Long-Evans rats were surgically implanted with epidural recording electrodes overlying visual cortex and tested 1 week later. Pattern reversal-evoked potent...

356

Listening to the brainstem: musicianship enhances intelligibility of subcortical representations for speech.  

PubMed

Auditory experiences including musicianship and bilingualism have been shown to enhance subcortical speech encoding operating below conscious awareness. Yet, the behavioral consequence of such enhanced subcortical auditory processing remains undetermined. Exploiting their remarkable fidelity, we examined the intelligibility of auditory playbacks (i.e., "sonifications") of brainstem potentials recorded in human listeners. We found naive listeners' behavioral classification of sonifications was faster and more categorical when evaluating brain responses recorded in individuals with extensive musical training versus those recorded in nonmusicians. These results reveal stronger behaviorally relevant speech cues in musicians' neural representations and demonstrate causal evidence that superior subcortical processing creates a more comprehensible speech signal (i.e., to naive listeners). We infer that neural sonifications of speech-evoked brainstem responses could be used in the early detection of speech-language impairments due to neurodegenerative disorders, or in objectively measuring individual differences in speech reception solely by listening to individuals' brain activity. PMID:25632143

Weiss, Michael W; Bidelman, Gavin M

2015-01-28

357

Cortical and brainstem plasticity in Tourette syndrome and obsessive-compulsive disorder.  

PubMed

Gilles de la Tourette syndrome is characterized by motor/vocal tics commonly associated with psychiatric disorders, including obsessive-compulsive disorder. We investigated primary motor cortex and brainstem plasticity in Tourette patients, exposed and unexposed to chronic drug treatment, with and without psychiatric disturbances. We also investigated primary motor cortex and brainstem plasticity in obsessive-compulsive disorder. We studied 20 Tourette patients with and without psychiatric disturbances, 15 with obsessive-compulsive disorder, and 20 healthy subjects. All groups included drug-naïve patients. We conditioned the left primary motor cortex with intermittent/continuous theta-burst stimulation and recorded motor evoked potentials. We conditioned the supraorbital nerve with facilitatory/inhibitory high-frequency stimulation and recorded the blink reflex late response area. In healthy subjects, intermittent theta-burst increased and continuous theta-burst stimulation decreased motor evoked potentials. Differently, intermittent theta-burst failed to increase and continuous theta-burst stimulation failed to decrease motor evoked potentials in Tourette patients, with and without psychiatric disturbances. In obsessive-compulsive disorder, intermittent/continuous theta-burst stimulation elicited normal responses. In healthy subjects and in subjects with obsessive-compulsive disorder, the blink reflex late response area increased after facilitatory high-frequency and decreased after inhibitory high-frequency stimulation. Conversely, in Tourette patients, with and without psychiatric disturbances, facilitatory/inhibitory high-frequency stimulation left the blink reflex late response area unchanged. Theta-burst and high-frequency stimulation elicited similar responses in drug-naïve and chronically treated patients. Tourette patients have reduced plasticity regardless of psychiatric disturbances. These findings suggest that abnormal plasticity contributes to the pathophysiology of Gilles de la Tourette syndrome. However, obsessive-compulsive disorder patients have normal cortical and brainstem plasticity. PMID:24996148

Suppa, Antonio; Marsili, Luca; Di Stasio, Flavio; Berardelli, Isabella; Roselli, Valentina; Pasquini, Massimo; Cardona, Francesco; Berardelli, Alfredo

2014-10-01

358

Refractive State of Tree Shrew Eyes Measured with Cortical Visual Evoked Potentials  

PubMed Central

Purpose To determine the refractive state of tree shrew eyes using visual evoked potentials (VEP's) recorded from primary visual cortex and compare the values with those obtained with streak retinoscopy and with an autorefractor. Methods VEP's were recorded in seven normal tree shrews and three animals in which ?5 D of myopia (relative to control eye) was induced by monocular ?5 D lens wear. While the animals were awake, refractive correction was measured with an autorefractor before and after cycloplegia (1% atropine and 2.5% phenylepherine). When anesthetized, cycloplegic refractive correction was measured with streak retinoscopy. Then VEP's were produced with square-wave counterphased (1 Hz) high-contrast checkerboard patterns near the animals' high spatial frequency cutoff. Spherical lenses (2 D steps) were placed before the eye, and the VEP (average of 128 sweeps) was measured to determine the lens that produced the largest first positive peak (P1). Results VEP's were obtained over a broad range of trial lenses. Tuning was narrower when check sizes were small. In normal and control eyes, the P1 amplitude was largest, on average, for a trial lens of (mean ± SD) ?0.6 ± 1.6 D (corrected for working distance but not vertex distance). The mean streak retinoscopy value (spherical equivalent at the corneal plane) was 7.0 ± 0.8 D, and mean autorefractor values were 4.0 ± 1.1 D (cycloplegic) and 3.7 ± 1.2 D (noncycloplegic). In the eyes that compensated for a ?5 D lens, the largest P1 values occurred with lenses with a power of ?6.3 ± 3.2 D. Thus, the VEP measure showed a similar treated vs. control eye difference as did streak retinoscopy (treated eyes, 4.7 ± 0.4 D myopic) and the autorefractor (treated eyes, 4.8 ± 0.5 D myopic). Conclusions Normal tree shrew eyes are approximately emmetropic. The hyperopic values obtained with streak retinoscopy and the autorefractor are consistent with the presence of a “small-eye artifact” in tree shrews. Eyes that have compensated for a ?5 D lens are myopic by approximately the value of the lens. PMID:14502042

NORTON, THOMAS T.; WU, WENDE W.; SIEGWART, JOHN T.

2007-01-01

359

Beta-zone parapapillary atrophy and multifocal visual evoked potentials in eyes with glaucomatous optic neuropathy.  

PubMed

We investigated changes in multifocal visual evoked potential (mfVEP) responses due to beta-zone parapapillary atrophy (ßPPA). 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 ßPPA. The ßPPA 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 ßPPA 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). ßPPA 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 ßPPA had significantly lower amplitudes and prolonged latencies than eyes without ßPPA, these differences were attributable to differences in SAP severity, age, and refractive error. Thus, ßPPA does not appear to be an independent factor affecting mfVEP responses in eyes with GON. PMID:21735265

De Moraes, Carlos Gustavo; Ketner, Scott; Teng, Christopher C; Ehrlich, Joshua R; Raza, Ali S; Liebmann, Jeffrey M; Ritch, Robert; Hood, Donald C

2011-08-01

360

Dipole source analyses of laser evoked potentials obtained from subdural grid recordings from primary somatic sensory cortex  

PubMed Central

The cortical potentials evoked by cutaneous application of a laser stimulus (laser evoked potentials, LEP) often include potentials in the primary somatic sensory cortex (S1), which may be located within the subdivisions of S1 including Brodmann areas 3A, 3B, 1, and 2. The precise location of the LEP generator may clarify the pattern of activation of human S1 by painful stimuli. We now test the hypothesis that the generators of the LEP are located in human Brodmann area 1 or 3A within S1. Local field potential (LFP) source analysis of the LEP was obtained from subdural grids over sensorimotor cortex in two patients undergoing epilepsy surgery. The relationship of LEP dipoles was compared with dipoles for somatic sensory potentials evoked by median nerve stimulation (SEP) and recorded in area 3B (see Baumgärtner U, Vogel H, Ohara S, Treede RD, Lenz FA. J Neurophysiol 104: 3029–3041, 2010). Both patients had an early radial dipole in S1. The LEP dipole was located medial, anterior, and deep to the SEP dipole, which suggests a nociceptive dipole in area 3A. One patient had a later tangential dipole with positivity posterior, which is opposite to the orientation of the SEP dipole in area 3B. The reversal of orientations between modalities is consistent with the cortical surface negative orientation resulting from superficial termination of thalamocortical neurons that receive inputs from the spinothalamic tract. Therefore, the present results suggest that the LEP may result in a radial dipole consistent with a generator in area 3A and a putative later tangential generator in area 3B. PMID:21593389

Baumgärtner, Ulf; Vogel, Hagen; Ohara, Shinji; Treede, Rolf-Detlef

2011-01-01

361

Towards an Optimization of Stimulus Parameters for Brain-Computer Interfaces Based on Steady State Visual Evoked Potentials  

PubMed Central

Efforts to construct an effective brain-computer interface (BCI) system based on Steady State Visual Evoked Potentials (SSVEP) commonly focus on sophisticated mathematical methods for data analysis. The role of different stimulus features in evoking strong SSVEP is less often considered and the knowledge on the optimal stimulus properties is still fragmentary. The goal of this study was to provide insight into the influence of stimulus characteristics on the magnitude of SSVEP response. Five stimuli parameters were tested: size, distance, colour, shape, and presence of a fixation point in the middle of each flickering field. The stimuli were presented on four squares on LCD screen, with each square highlighted by LEDs flickering with different frequencies. Brighter colours and larger dimensions of flickering fields resulted in a significantly stronger SSVEP response. The distance between stimulation fields and the presence or absence of the fixation point had no significant effect on the response. Contrary to a popular belief, these results suggest that absence of the fixation point does not reduce the magnitude of SSVEP response. However, some parameters of the stimuli such as colour and the size of the flickering field play an important role in evoking SSVEP response, which indicates that stimuli rendering is an important factor in building effective SSVEP based BCI systems. PMID:25398134

Radzikowska, Zofia; Milanowski, Piotr; Ku?, Rafa?; Suffczy?ski, Piotr; Michalska, Magdalena; ?ab?cki, Maciej; Zwoli?ski, Piotr; Durka, Piotr

2014-01-01

362

Comparison of visually evoked local field potentials in isolated turtle brain: Patterned versus blank stimulation  

Microsoft Academic Search

Isolated turtle brain\\/eye preparation has recently been used as a bloodless animal model for detecting the magnetic resonance imaging (MRI) signal changes produced by visually evoked neuronal currents. The present work aims to determine whether checkerboard-patterned or full field flash (blank) stimulation should be used in order to achieve stronger neuronal responses in turtle brain\\/eye preparation. The knowledge gained in

Qingfei Luo; Huo Lu; Hanbing Lu; Yihong Yang; Jia-Hong Gao

2010-01-01

363

Topographic recordings of auditory evoked potentials to speech: Subcortical and cortical responses.  

PubMed

Topographies of speech auditory brainstem response (speech ABR), a fine electrophysiological marker of speech encoding, have never been described. Yet, they could provide useful information to assess speech ABR generators and better characterize populations of interest (e.g., musicians, dyslexics). We present here a novel methodology of topographic speech ABR recording, using a 32-channel low sampling rate (5?kHz) EEG system. Quality of speech ABRs obtained with this conventional multichannel EEG system were compared to that of signals simultaneously recorded with a high sampling rate (13.3?kHz) EEG system. Correlations between speech ABRs recorded with the two systems revealed highly similar signals, without any significant difference between their signal-to-noise ratios (SNRs). Moreover, an advanced denoising method for multichannel data (denoising source separation) significantly improved SNR and allowed topography of speech ABR to be recovered. PMID:25329609

Bellier, Ludovic; Bouchet, Patrick; Jeanvoine, Arnaud; Valentin, Olivier; Thai-Van, Hung; Caclin, Anne

2014-10-20

364

Block-Dependent Sedation during Epidural Anaesthesia is Associated with Delayed Brainstem Conduction  

PubMed Central

Neuraxial anaesthesia produces a sedative and anesthetic-sparing effect. Recent evidence suggests that spinal cord anaesthesia modifies reticulo-thalamo-cortical arousal by decreasing afferent sensory transmission. We hypothesized that epidural anaesthesia produces sensory deafferentation-dependent sedation that is associated with impairment of brainstem transmission. We used brainstem auditory evoked potentials (BAEP) to evaluate reticular function in 11 volunteers. Epidural anaesthesia was induced with 2% 2-chloroprocaine. Hemodynamic and respiratory responses, sensory block level, sedation depth and BAEP were assessed throughout induction and resolution of epidural anaesthesia. Sedation was evaluated using verbal rating score (VRS), observer's assessment alertness/sedation (OAA/S) score, and bispectral index (BIS). Prediction probability (PK) was used to associate sensory block with sedation, as well as BIS with other sedation measures. Spearman rank order correlation was used to associate block level and sedation with the absolute and interpeak BAEP latencies. Sensory block level significantly predicted VRS (PK = 0.747), OAA/S score (PK = 0.748) and BIS. Bispectral index predicted VRS and OAA/S score (PK = 0.728). The latency of wave III of BAEP significantly correlated with sedation level (rho = 0.335, P < 0.01) and sensory block (rho = 0.394, P < 0.01). The other BAEP parameters did not change during epidural anaesthesia. Hemodynamic and respiratory responses remained stable throughout the study. Sedation during epidural anaesthesia depends on sensory block level and is associated with detectable block-dependent alterations in the brainstem auditory evoked responses. Sensory deafferentation may reduce CNS alertness through mechanisms related to brainstem neural activity. PMID:15220178

Wadhwa, Anupama; Shah, Yunus M.; Lin, Chum-Ming; Haugh, Gilbert S.; Sessler, Daniel I.

2005-01-01

365

The effect of progressively increased physical efforts on visual evoked potentials in volleyball players and non-athletes.  

PubMed

We assessed the effect of physical effort with increasing intensity on neural activity in the visual pathway in volleyball players (n = 10) and non-athletes (n = 10). Participants performed three 10-min tests of increasing intensity on a cycle ergometer. Each participant was assigned individual workloads below the lactate threshold (40% [Vdot]O(2max)), at the lactate threshold (65-75% [Vdot]O(2max)), and above the lactate threshold (80% [Vdot]O(2max)). Four recordings of visual evoked potentials were made: pre-exercise and immediately after each of the three subsequent tests. We assessed neural activity of the visual pathway by examining the amplitude and latency of the N75, P100, and N135 components of the visual evoked potentials waveform. Pre-exercise P100 wave latency was shorter (P < 0.05) in volleyball players than in non-athletes. In non-athletes, the latency of P100 following the first and second effort (40% and 65-75% [Vdot]O(2max)) was reduced compared with pre-exercise (P < 0.01). However, P100 latency increased and P100 amplitude decreased after the third test (80% [Vdot]O(2max)) in non-athletes. In contrast, no significant changes in the latency or amplitude of visual evoked potentials were observed in the athletes in the three tests. Neural conductivity in the visual pathway after exercise might be at least partially dependent on the individual's personal training adaptation status. PMID:21995434

Zwierko, Teresa; Lubi?ski, Wojciech; Lubkowska, Anna; Niechwiej-Szwedo, Ewa; Czepita, Damian

2011-11-01

366

Differences between congenitally blind and normally sighted subjects in the P1 component of middle latency auditory evoked potentials.  

PubMed

Auditory evoked potentials (0 to 100 msec. range) were recorded two times for 9 congenitally blind children (age = 14.1 yr. +/- 1.4 yr) and 9 age-matched children with normal vision. The groups' peak latency and amplitude of the P1 wave were compared. The peak latency was significantly lower for the congenitally blind than for the normally sighted on a two-factor analysis of variance. Since the P1 wave is thought to correspond to either the ascending reticular activating system or the primary auditory cortex, these results suggest that information processing at these neural levels may occur more efficiently in the blind. PMID:9700792

Naveen, K V; Srinivas, R; Nirmala, K S; Nagarathna, R; Nagendra, H R; Telles, S

1998-06-01

367

Effects of Motion Sickness Severity on the Vestibular-Evoked Myogenic Potentials  

PubMed Central

Background Motion sickness is a common debilitating condition associated with both actual and perceived motion. Despite the commonality, little is known about the underlying physiological mechanisms. One theory proposes that motion sickness arises from a mismatch between reality and past experience in vertical motions. Physiological tests of the vestibular system, however, have been inconclusive regarding the underlying pathogenesis. Cervical vestibular-evoked myogenic potentials (cVEMPs) arise from the saccule, which responds to vertical motion. If vertical motion elicits motion sickness, the cVEMP should be affected. Purpose The purpose of this investigation was to determine if cVEMP characteristics differ among individuals with a range of motion sickness susceptibility from negligible to severe. The hypothesis was that individuals with high susceptibility would have larger cVEMP amplitudes and shorter cVEMP latencies relative to those who are resistant to motion sickness. Research Design The study had two parts. The first was quasi-experimental in which participants comprised three groups based on susceptibility to motion sickness (low, mild-moderate, high) as identified on the short version of the Motion Sickness Susceptibility Questionnaire (MSSQ-S). The second part of the study was correlational and evaluated the specific relationships between the degree of motion sickness susceptibility and characteristics of the VEMPs. Study Sample A total of 24 healthy young adults (ages 20–24 yr) were recruited from the university and the community without regard to motion sickness severity. Data Collection and Analysis Participants took the MSSQ-S, which quantifies susceptibility to motion sickness. The participants had a range of motion sickness susceptibility with MSSQ raw scores from 0.0–36.6, which correspond to percent susceptibility from 0.0–99.3%. VEMPs were elicited by 500 Hz tone-bursts monaurally in both ears at 120 dB pSPL. MSSQ-S percent scores were used to divide the participants into low, mild-moderate, and high susceptibility groups. A fixed general linear model with repeated-measures analysis of variance tested cVEMP characteristics for the susceptibility groups (between participants) and ears (within participants). A univariate analysis of variance tested the cVEMP interaural amplitudes across groups. The second analysis was a regression of the severity of motion sickness in percent on cVEMP characteristics. Significance was defined as p < 0.05. Results Participants in the high susceptibility group had significantly higher cVEMP amplitudes than those in the low susceptibility group. cVEMP amplitudes did not differ between ears, and latencies did not differ between the two groups or between ears. Regression analysis on MSSQ-S percent susceptibility by VEMP amplitudes revealed a best-fit cubic function in both ears, with r2 values of more than 42%. The interaural asymmetry ratio was negatively associated with motion sickness susceptibility (r2 = 0.389). Conclusions The current study is the first to report that greater susceptibility to motion sickness is associated with larger cVEMP amplitudes and lower interaural cVEMP asymmetries. Larger interaural asymmetries in cVEMPs did not promote motion sickness susceptibility. The cVEMP findings implicate the saccule and its neural pathways in the production of motion sickness and are consistent with the theory that vertical motions elicit motion sickness. Motion sickness susceptibility may contribute to the variability in normative cVEMP amplitudes. PMID:25405837

Fowler, Cynthia G.; Sweet, Amanda; Steffel, Emily

2015-01-01

368

Field potentials evoked in the brain stem of the cat by stimulation of the carotid sinus, glossopharyngeal, aortic and superior laryngeal nerves  

PubMed Central

1. In a primarily topographical study, the field potentials evoked in the brain stem of the cat by stimulation of the sinus, glossopharyngeal (IX), aortic and superior laryngeal (SLN) nerves have been recorded with glass micro-electrodes. 2. Extracellular negative potentials were evoked in the region of the nucleus of the tractus solitarius and in the lateral reticular formation (LRF) by electrical stimulation of all four nerves. There were differences in the form of these potentials amongst the nerves, particularly between sinus-IX and aortic-SLN. The potentials were identified as post-synaptic with early and late components and were sometimes preceded by an afferent volley. 3. Extracellular positive potentials were evoked in the subnucleus reticularis medialis medullae oblongatae and the nucleus reticularis gigantocellularis. Intracellularly recorded hyperpolarizations recorded from six cells had the same time course as the extracellular positivity. Spontaneously active cells encountered in these regions were sometimes depressed for the duration of the positivity. 4. Each of the above field potentials was maximal in the region of Horsley—Clarke A. P. co-ordinates -10 to -13 mm. 5. At A.P. co-ordinates of -15 to -17 mm negativity showing post-tetanic potentiation was evoked, at latencies similar to the negativity in the LRF, in the commissural nucleus of Cajal, the dorsolateral reticular formation and the medial reticulo-spinal tract. 6. Negative potentials were evoked in the contralateral LRF. PMID:5499531

Biscoe, T. J.; Sampson, S. R.

1970-01-01

369

Convergence characteristics of two algorithms in non-linear stimulus artefact cancellation for electrically evoked potential enhancement.  

PubMed

Somatosensory evoked potentials (SEPs) are a sub-class of evoked potentials (EPs) that are very useful in diagnosing various neuromuscular disorders and in spinal cord and peripheral-nerve monitoring. Most often, the measurements of these signals are contaminated by stimulus-evoked artefact. Conventional stimulus-artifact (SA) reduction schemes are primarily hardware-based and rely on some form of input blanking during the SA phase. This procedure can result in partial SEP loss if the tail of the SA interferes with the SEP. Adaptive filters offer an attractive solution to this problem by iteratively reducing the SA waveform while leaving the SEP intact. Owing to the inherent non-linearities in the SA generation system, non-linear adaptive filters (NAFs) are most suitable. SA reduction using NAFs based on truncated second-order Volterra expansion series is investigated. The focus is on the performance of two main adaptation algorithms, the least mean square (LMS) and recursive least squares (RLS) algorithms, in the context of non-linear adaptive filtering. A comparison between the convergence and performance characteristics of these two algorithms is made by processing both simulated and experimental SA data. It is found that, in high artefact-to-noise ratio (ANR) SA cancellation, owing to the large eigenvalue spreads, the RLS-based NAF is more efficient than the LMS-based NAF. However, in low-ANR scenarios, the RLS- and LMS-based NAFs exhibit similar convergence properties, and the computational simplicity of the LMS-based NAFs makes them the preferred option. PMID:9684461

Parsa, V; Parker, P; Scott, R

1998-03-01

370

Effects of high dietary sulfur on brain functions using evoked potentials technique.  

PubMed

Brain stem auditory-evoked response (BAER) is a noninvasive technique used for detecting neurophysiological abnormalities of the brain stem along the auditory pathway. Brain stem auditory-evoked response recordings were obtained from subcutaneous skin electrodes from two control sheep and 22 other sheep fed high sulfur (S) diets with low or high concentration of thiamine (B1), copper (Cu), and molybdenum (Mo). At least four peaks (I,II,III,IV) of varied amplitude were observed in all animals. Neurophysiological abnormalities due to decreased conductivity and/or excitability of nerve fibers along the auditory pathway were found on the BAER recordings of sheep fed high S diet. Abnormalities of peaks and interpeak latencies within BAER recordings were related to histopathological observations of brain stem lesions. Lesions in the areas of the cochlear nuclei and lateral lemniscus were seen in conjunction with altered BAER components. However, abnormalities in BAER recordings and lesions in the brain stem also occurred in the absence of overt clinical signs. Analysis of interpeak latencies between peaks I and IV revealed significant differences among dietary groups. Sheep given diets low in Cu, Mo, and B1 were affected most. Factorial analysis indicated B1 and interactions among Cu, Mo, and B1 as significant factors influencing interpeak latencies. PMID:2306659

Olkowski, A A; Gooneratne, S R; Crichlow, E C; Rousseaux, C G; Christensen, D A

1990-01-01

371

Assessment of otolith function using cervical and ocular vestibular evoked myogenic potentials in individuals with motion sickness.  

PubMed

The involvement of otolith organs in motion sickness has long been debated; however, equivocal findings exist in literature. The present study thus aimed at evaluating the otolith functioning in individuals with motion sickness. Cervical and ocular vestibular evoked myogenic potentials were recorded from 30 individuals with motion sickness, 30 professional drivers and 30 healthy individuals. The results revealed no significant difference in latencies and amplitudes between the groups (p>0.05). Nonetheless, thresholds were significantly elevated and inter-aural asymmetry ratio significantly higher in motion sickness susceptible group (p < 0.001) for both the potentials. All the individuals in the motion sickness group had high asymmetry ratio at least on one of the two potentials. Thus, reduced response and/or asymmetric otolithic function seem the likely reasons behind motion sickness susceptibility. PMID:25220694

Singh, Niraj Kumar; Pandey, Preeti; Mahesh, Soumya

2014-12-01

372

Clinical Use of Skull Tap Vestibular Evoked Myogenic Potentials for the Diagnoses of the Cerebellopontine Angle Tumor Patients  

PubMed Central

Objective. To document our experiences using a new skull tapping induced Vestibular Evoked Myogenic Potentials (tap VEMPs) technique combined with standard Auditory Vestibular Evoked Myogenic Potentials (AC VEMPs) for advanced clinical assessment of cerebellopontine angle tumor (CPAT) patients. Design and Study Sample. Three patients were selected in order to highlight observations shown in a larger patient population and to show the variability of the findings. Both tap VEMPs and AC VEMPs were acquired from the sternocleidomastoid muscle (SCM) with EMG-based biofeedback and monitoring. Results. The usefulness of VEMPs was demonstrated, indicating the presence of a tumor and contributing additional information as to the involved nerve bundles in two out of the three cases. Conclusion. Due to the sensory organ dependency and related innervations differences, acquiring both AC VEMPs and tap VEMPs is likely to increase the probability of diagnosing CPATs and provide more information on the involved vestibular nerve bundles. This study demonstrates the feasibility of the possible expansion and combination of tap VEMPs and AC VEMPs techniques into a clinical diagnostic battery for advanced assessment of CPAT patients and its contribution as a guideline for the use of tap VEMPs in general. PMID:24804198

Yavuz, Erdem; Lachowska, Magdalena; Piercha?a, Katarzyna; Morawski, Krzysztof; Niemczyk, Kazimierz; Delgado, Rafael E.

2014-01-01

373

Enhanced Detection of Visual-Evoked Potentials in Brain-Computer Interface Using Genetic Algorithm and Cyclostationary Analysis  

PubMed Central

We propose a novel framework to reduce background electroencephalogram (EEG) artifacts from multitrial visual-evoked potentials (VEPs) signals for use in brain-computer interface (BCI) design. An algorithm based on cyclostationary (CS) analysis is introduced to locate the suitable frequency ranges that contain the stimulus-related VEP components. CS technique does not require VEP recordings to be phase locked and exploits the intertrial similarities of the VEP components in the frequency domain. The obtained cyclic frequency spectrum enables detection of VEP frequency band. Next, bandpass or lowpass filtering is performed to reduce the EEG artifacts using these identified frequency ranges. This is followed by overlapping band EEG artifact reduction using genetic algorithm and independent component analysis (G-ICA) which uses mutual information (MI) criterion to separate EEG artifacts from VEP. The CS and GA methods need to be applied only to the training data; for the test data, the knowledge of the cyclic frequency bands and unmixing matrix would be sufficient for enhanced VEP detection. Hence, the framework could be used for online VEP detection. This framework was tested with various datasets and it showed satisfactory results with very few trials. Since the framework is general, it could be applied to the enhancement of evoked potential signals for any application. PMID:18354722

Gupta, Cota Navin; Palaniappan, Ramaswamy

2007-01-01

374

The need to add motor evoked potential monitoring to somatosensory and electromyographic monitoring in cervical spine surgery  

PubMed Central

Intraoperative neural monitoring (IONM), utilizing somatosensory evoked potentials (SEP) and electromyography (EMG), was introduced to cervical spine surgery in the late 1980's. However, as SEP only provided physiological data regarding the posterior cord, new motor deficits were observed utilizing SEP alone. This prompted the development of motor evoked potential monitoring (MEP) which facilitated real-time assessment of the anterior/anterolateral spinal cord. Although all three modalities, SEP, EMG, and MEP, are routinely available for IONM of cervical spine procedures, MEP are not yet routinely employed. The purpose of this review is to emphasize that MEP should now routinely accompany SEP and EMG when performing IONM of cervical spine surgery. Interestingly, one of the most common reasons for malpractice suits involving the cervical spine, is quadriparesis/quadriplegia following a single level anterior cervical diskectomy and fusion (ACDF). Previously, typical allegations in these suits included; negligent surgery, lack of informed consent, failure to diagnose/treat, and failure to brace. Added to this list, perhaps, as the 5th most reason for a suit will be failure to monitor with MEP. This review documents the value of MEP monitoring in addition to SEP and EMG monitoring in cervical spine surgery. The addition of MEP0 should minimize major motor injuries, and more accurately and reliably detect impending anterior cord deterioration that may be missed with SEP monitoring alone. PMID:24340237

Epstein, Nancy E.

2013-01-01

375

Radiation Associated Brainstem Injury  

SciTech Connect

Publications relating brainstem radiation toxicity to quantitative dose and dose-volume measures derived from three-dimensional treatment planning were reviewed. Despite the clinical importance of brainstem toxicity, most studies reporting brainstem effects after irradiation have fewer than 100 patients. There is limited evidence relating toxicity to small volumes receiving doses above 60-64 Gy using conventional fractionation and no definitive criteria regarding more subtle dose-volume effects or effects after hypofractionated treatment. On the basis of the available data, the entire brainstem may be treated to 54 Gy using conventional fractionation using photons with limited risk of severe or permanent neurological effects. Smaller volumes of the brainstem (1-10 mL) may be irradiated to maximum doses of 59 Gy for dose fractions <=2 Gy; however, the risk appears to increase markedly at doses >64 Gy.

Mayo, Charles, E-mail: charles.mayo@umassmemorial.or [Department of Radiation Oncology, University of Massachusetts Medical School, Worcester, MA (United States); Yorke, Ellen [Department of Medical Physics, Memorial Sloan Kettering Hospital, New York, NY (United States); Merchant, Thomas E. [Division of Radiation Oncology, St. Jude Children's Research Hospital, Memphis, TN (United States)

2010-03-01

376

Action Potential-Evoked Calcium Release Is Impaired in Single Skeletal Muscle Fibers from Heart Failure Patients  

PubMed Central

Background Exercise intolerance in chronic heart failure (HF) has been attributed to abnormalities of the skeletal muscles. Muscle function depends on intact excitation-contraction coupling (ECC), but ECC studies in HF models have been inconclusive, due to deficiencies in the animal models and tools used to measure calcium (Ca2+) release, mandating investigations in skeletal muscle from HF patients. The purpose of this study was to test the hypothesis that Ca2+ release is significantly impaired in the skeletal muscle of HF patients in whom exercise capacity is severely diminished compared to age-matched healthy volunteers. Methods and Findings Using state-of-the-art electrophysiological and optical techniques in single muscle fibers from biopsies of the locomotive vastus lateralis muscle, we measured the action potential (AP)-evoked Ca2+ release in 4 HF patients and 4 age-matched healthy controls. The mean peak Ca2+ release flux in fibers obtained from HF patients (10±1.2 µM/ms) was markedly (2.6-fold) and significantly (p<0.05) smaller than in fibers from healthy volunteers (28±3.3 µM/ms). This impairment in AP-evoked Ca2+ release was ubiquitous and was not explained by differences in the excitability mechanisms since single APs were indistinguishable between HF patients and healthy volunteers. Conclusions These findings prove the feasibility of performing electrophysiological experiments in single fibers from human skeletal muscle, and offer a new approach for investigations of myopathies due to HF and other diseases. Importantly, we have demonstrated that one step in the ECC process, AP-evoked Ca2+ release, is impaired in single muscle fibers in HF patients. PMID:25310188

DiFranco, Marino; Quiñonez, Marbella; Shieh, Perry; Fonarow, Gregg C.; Cruz, Daniel; Deng, Mario C.; Vergara, Julio L.; Middlekauff, Holly R.

2014-01-01

377

The origin, and application of somatosensory evoked potentials as a neurophysiological technique to investigate neuroplasticity  

PubMed Central

Somatosensory evoked potentionals (SEPs) can be used to elucidate differences in cortical activity associated with a spinal manipulation (SM) intervention. The purpose of this narrative review is to overview the origin and application of SEPs, a neurophysiological technique to investigate neuroplasticity. Summaries of: 1) parameters for SEP generation and waveform recording; 2) SEP peak nomenclature, interpretation and generators; 3) peaks pertaining to tactile information processing (relevant to both chiropractic and other manual therapies); 4) utilization and application of SEPs; 5) SEPs concurrent with an experimental task and at baseline/control/pretest; 6) SEPs pain studies; and 7) SEPs design (pre/post) and neural reorganization/neuroplasticity; and 8) SEPs and future chiropractic research are all reviewed. Understanding what SEPs are, and their application allows chiropractors, educators, and other manual therapists interested in SM to understand the context, and importance of research findings from SM studies that involve SEPs. PMID:24932021

Passmore, Steven R.; Murphy, Bernadette; Lee, Timothy D.

2014-01-01

378

Air- and bone-conducted Vestibular Evoked Myogenic Potentials (VEMPs) in otosclerosis: recordings before and after stapes surgery  

PubMed Central

Summary Aim of the study was to investigate, in a randomized prospective trial, air-conducted vestibular evoked myogenic potentials (AC-VEMPs) and bone-conducted vestibular evoked myogenic potentials (BC-VEMPs) before and after successful stapedotomy. Enrolled in the study were 41 consecutive patients (32 female, 9 male; mean age 36 years) (42 ears) with otosclerosis. Audiological evaluations and diagnosis of otosclerosis were made according to the guidelines of the Committee on Hearing and Equilibrium. Successful stapedotomy was carried out in all otosclerotic ears. Air- and bone-conducted 4-frequency pure tone average (4-PTA), air-bone gap (ABG), AC- and BC-VEMPs were evaluated pre- and post-operatively. As far as concerns results, pre-operatively, AC- and BC-VEMPs could be recorded in 9 (21.4%) and 16 (38.1%) otosclerotic ears, respectively. Lower ABG was detected in patients with AC-VEMPs in comparison to those in whom air-conducted potentials (p = 0.032) could not be elicited. At 12-month post-operative follow-up, AC-VEMPs were present in 11 (26.2%) ears, while BC-VEMPs could be elicited in 15 (35.7%) cases. Reduced bone-conduction 4-PTA was observed in patients with BC-VEMPs in comparison to those without recordable bone-conducted potentials pre- and post-operatively (p = 0.003 and p = 0.005, respectively). A significantly (p = 0.022) lower air-conducted 4-PTA was measured post-stapedotomy in patients with BC-VEMPs in comparison to those without elicitable bone-conducted potentials. In conclusion, VEMPs reduced elicitability, in otosclerosis, is likely due to conductive hearing loss and inner ear impairment. PMID:20559467

Trivelli, M; D’Ascanio, L; Pappacena, M; Greco, F; Salvinelli, F

2010-01-01

379

CENTRAL NERVOUS SYSTEM ACTIVITY ASSOCIATED WITH PAIN EVOKED BY BRADYKININ AND ITS ALTERATION BY MORPHINE AND ASPIRIN  

PubMed Central

Synthetic bradykinin, a nonapeptide formed from ?-2 globulin in plasma, injected intra-arterially or intraperitoneally in cats in doses of 10-50 ?g, evoked activity in the central nervous system in pathways associated with the signaling of pain. Similar injections of bradykinin in intact normal cats and dogs evoked manifestations of pain, and in conscious humans elicited verbal reports of pain perceived in the area of injection. Single unit activity was recorded in the medial reticular formation of the brainstem, in the medial thalamus and, more laterally, among the posterior group nuclei and the suprageniculate nucleus. Bradykinin did not evoke any cortical or subcortical slow potentials such as those evoked by electrical stimulation of the foot pads. When bradykinin was given together with the electrical stimulus, the responses evoked by the latter were blocked. Morphines uppressed bradykinin-evoked activity. Aspirin caused marked fluctuations in activity, unrelated to the bradykinin injection; the bradykinin block of evoked potentials could no longer be observed after aspirin dosage. The results are discussed in terms of the peripheral and central sites of analgesic action and the likelihood of the existence of chemosensitive pain receptors. PMID:5259760

Lim, R. K. S.; Krauthamer, G.; Guzman, F.; Fulp, R. R.

1969-01-01

380

Contribution of Vestibular-Evoked Myogenic Potential (VEMP) testing in the assessment and the differential diagnosis of otosclerosis  

PubMed Central

Background The aim of this prospective clinical study was to evaluate the clinical importance of Vestibular-Evoked Myogenic Potentials (VEMPs) in the assessment and differential diagnosis of otosclerosis and otologic diseases characterized by “pseudo-conductive” components. We also investigated the clinical appearance of balance disorders in patients with otosclerosis by correlating VEMP results with the findings of caloric testing and pure tone audiometry(PTA). Material/Methods Air-conducted(AC) 4-PTA, bone-conducted(BC) 4-PTA, air-bone Gap(ABG), AC, BC tone burst evoked VEMP, and calorics were measured preoperatively in 126 otosclerotic ears. Results The response rate of the AC-VEMPs and BC-VEMPs was 29.36% and 44.03%, respectively. Statistical differences were found between the means of ABG, AC 4-PTA, and BC 4-PTA in the otosclerotic ears in relation to AC-VEMP elicitability. About one-third of patients presented with disequilibrium. A statistically significant interaction was found between calorics and dizziness in relation to PTA thresholds. No relationship was found between calorics and dizziness with VEMPs responses. Conclusions AC and BC VEMPs can be elicited in ears with otosclerosis. AC-VEMP is more vulnerable to conductive hearing loss. Evaluation of AC-VEMP thresholds can be added in the diagnostic work-up of otosclerosis in case of doubt, enhancing differential diagnosis in patients with air-bone gaps. Otosclerosis is not a cause of canal paresis or vertigo. PMID:24509900

Tramontani, Ourania; Gkoritsa, Eleni; Ferekidis, Eleftherios; Korres, Stavros G.

2014-01-01

381

and Brainstem Aage R. Mller  

E-print Network

Cochlear and Brainstem Implants Editor Aage R. Møller Contents Introduction: Møller A.R. History of Cochlear Implants and Auditory Brainstem Implants: Møller A.R. Cochlear Implants Surgical Aspects Implants: Loizou P.C. Auditory Brainstem Implants Auditory Brainstem Implants: Surgical Aspects: Fayad J

O'Toole, Alice J.

382

A new method for registration of kinesthetic evoked potentials for studies of proprioceptive sensitivity in normal subjects and patients with organic lesions in the brain.  

PubMed

The proprioceptive sensitivity of healthy volunteers and convalescents after acute cerebrovascular episodes was studied by a new neurophysiological method for registration of kinesthetic evoked potentials emerging in response to passive 50(o) bending of the hand in the wrist joint with the angular acceleration of 350 rad/sec(2). Kinesthetic evoked potentials were recorded above the somatosensory cortex projection areas in the hemispheres contra- and ipsilateral to the stimulated limb. The patients exhibited significantly longer latencies and lesser amplitudes of the early components of response in the involved hemisphere in comparison with normal subjects. The method for registration of the kinesthetic evoked potentials allows a more detailed study of the mechanisms of kinesthetic sensitivity in health and in organic involvement of the brain. PMID:25567199

Gordeev, S A; Voronin, S G

2015-01-01

383

Innovative neurophysiological methods in itch research: long-latency evoked potentials after electrical and thermal stimulation in patients with atopic dermatitis.  

PubMed

The aim of this study was to examine the findings of innovative neurophysiological methods of itch research. Short-latency and pain-related somatosensory-evoked potentials after electrical stimulation, as well as long-latency evoked potentials after thermal stimulation were studied in 38 patients with atopic dermatitis (AD) and 26 healthy volunteers. Quantitative Sensory Testing of thermal perception was performed in 22 patients with AD from the main AD group and in 15 healthy volunteers. Brain hyperactivity to electrical stimuli, delayed thermal-evoked potentials and elevated thermal thresholds were revealed in patients with AD compared with healthy controls. The data indicate small nerve fibre dysfunction in patients with AD, which may contribute to the pathogenesis of AD and chronic itch. The study demonstrates objective approaches to assess the function of small nerve fibres in patients with chronic itch. PMID:21710104

Yudina, Marina M; Toropina, Galina G; Lvov, Andrey; Gieler, Uwe

2011-10-01

384

In-air evoked potential audiometry of grey seals (Halichoerus grypus) from the North and Baltic Seas.  

PubMed

In-air anthropogenic sound has the potential to affect grey seal (Halichoerus grypus) behaviour and interfere with acoustic communication. In this study, a new method was used to deliver acoustic signals to grey seals as part of an in-air hearing assessment. Using in-ear headphones with adapted ear inserts allowed for the measurement of auditory brainstem responses (ABR) on sedated grey seals exposed to 5-cycle (2-1-2) tone pips. Thresholds were measured at 10 frequencies between 1-20 kHz. Measurements were made using subcutaneous electrodes on wild seals from the Baltic and North Seas. Thresholds were determined by both visual and statistical approaches (single point F-test) and good agreement was obtained between the results using both methods. The mean auditory thresholds were ?40 dB re 20 µPa peak equivalent sound pressure level (peSPL) between 4-20 kHz and showed similar patterns to in-air behavioural hearing tests of other phocid seals between 3 and 20 kHz. Below 3 kHz, a steep reduction in hearing sensitivity was observed, which differed from the rate of decline in sensitivity obtained in behavioural studies on other phocids. Differences in the rate of decline may reflect influence of the ear inserts on the ability to reliably transmit lower frequencies or interference from the structure of the distal end of the ear canal. PMID:24632891

Ruser, Andreas; Dähne, Michael; Sundermeyer, Janne; Lucke, Klaus; Houser, Dorian S; Finneran, James J; Driver, Jörg; Pawliczka, Iwona; Rosenberger, Tanja; Siebert, Ursula

2014-01-01

385

Early and late activity in somatosensory cortex reflects changes in bodily self-consciousness: an evoked potential study.  

PubMed

How can we investigate the brain mechanisms underlying self-consciousness? Recent behavioural studies on multisensory bodily perception have shown that multisensory conflicts can alter bodily self-consciousness such as in the "full body illusion" (FBI) in which changes in self-identification with a virtual body and tactile perception are induced. Here we investigated whether experimental changes in self-identification during the FBI are accompanied by activity changes in somatosensory cortex by recording somatosensory-evoked potentials (SEPs). To modulate self-identification, participants were filmed by a video camera from behind while their backs were stroked, either synchronously (illusion condition) or asynchronously (control condition) with respect to the stroking seen on their virtual body. Tibial nerve SEPs were recorded during the FBI and analysed using evoked potential (EP) mapping. Tactile mislocalisation was measured using the crossmodal congruency task. SEP mapping revealed five sequential periods of brain activation during the FBI, of which two differed between the illusion condition and the control condition. Activation at 30-50 ms (corresponding to the P40 component) in primary somatosensory cortex was stronger in the illusion condition. A later activation at ?110-200 ms, likely originating in higher-tier somatosensory regions in parietal cortex, was stronger and lasted longer in the control condition. These data show that changes in bodily self-consciousness modulate activity in primary and higher-tier somatosensory cortex at two distinct processing steps. We argue that early modulations of primary somatosensory cortex may be a consequence of (1) multisensory integration of synchronous vs. asynchronous visuo-tactile stimuli and/or (2) differences in spatial attention (to near or far space) between the conditions. The later activation in higher-tier parietal cortex (and potentially other regions in temporo-parietal and frontal cortex) likely reflects the detection of visuo-tactile conflicts in the asynchronous condition. PMID:22546336

Aspell, J E; Palluel, E; Blanke, O

2012-08-01

386

RAT AND HUMAN VISUAL-EVOKED POTENTIALS RECORDED UNDER COMPARABLE CONDITIONS: A PRELIMINARY ANALYSIS TO ADDRESS THE ISSUE OF PREDICTING HUMAN NEUROTOXIC EFFECTS  

EPA Science Inventory

A search was undertaken for contributions of sustained and transient visual elements to the rat visual-evoked potential (VEP) using procedures similar to those used in humans (Hudnell et al., in preparation). voked potentials were recorded following either pattern-reversal or pat...

387

Direction-dependent spectral sensitivity and interaural spectral difference in a dolphin: evoked potential study.  

PubMed

Sensitivity and interaural intensity difference (IID) dependence on sound frequency and direction was measured in an Amazon river dolphin Inia geoffrensis by recording the auditory nerve evoked response from the body surface. The maximal sensitivity in the horizontal plane was found when the sound direction was 5 degrees to 10 degrees ipsilateral to the recorded ear; the direction dependence of sensitivity was more pronounced at higher frequencies than at lower ones. The IID reached its peak at small azimuthal angles (7.5 degrees to 15 degrees) and higher sound frequencies (100 kHz), or at large azimuthal angles (30 degrees to 45 degrees) and lower sound frequencies (20 to 30 kHz). Each sound direction featured its specific pattern of spectral sensitivity and of interaural spectral difference. The interaural spectral difference fluctuated within a range of more than 20 dB depending on sound direction. The data indicate that interaural intensity as well as spectral difference may be cues for binaural localization of sound direction by dolphins. PMID:8326074

Supin AYa; Popov, V V

1993-06-01

388

Dissociation of frontal and parietal components of somatosensory evoked potentials in severe head injury.  

PubMed

Reports on the topography of SEPs in non-comatose patients have drawn attention to a second thalamo-cortical loop connecting the thalamus with the frontal cortex, which has a close anatomical relation to the fronto-limbic structures frequently damaged in severe head injury (SHI). We studied whether the frontal component (P20/22) of the somatosensory evoked response (SEP), known to be due to a generator different from that of the traditionally analysed parietal SEP component (N20), would be differently affected by SHI. Moreover, we examined whether its analysis would improve the prognostic evaluation in the Glasgow outcome scale (GOS) after 3-6 months. In 50 patients examined within 72 h after the injury we found a dissociated impairment of frontal and parietal components in 24% of the recorded SEPs. When both frontal and parietal components were used as predictors, discriminant analysis correctly classified 94% of the patients into good (GOS good recovery and moderate disability) or poor (GOS severe disability, persistent vegetative state or death) outcome groups. Classification was less accurate and misclassifications grosser when considering parietal or frontal parameters alone. Our results show that (i) the evaluation of frontal components provides information different from that of the parietal SEPs, confirming the presence of different generators, and (ii) a combined analysis of the two components improves the prognostic evaluation with regard to the global outcome. PMID:7691561

Gütling, E; Gonser, A; Regard, M; Glinz, W; Landis, T

1993-01-01

389

Solid and hollow pedicle screws affect the electrical resistance: A potential source of error with stimulus-evoked electromyography  

PubMed Central

Background: Although stimulus evoked electromyography (EMG) is commonly used to confirm the accuracy of pedicle screw placement. There are no studies to differentiate between solid screws and hollow screws to the electrical resistance of pedicle screws. We speculate that the electrical resistance of the solid and hollow pedicle screws may be different and then a potential source of error with stimulus-evoked EMG may happen. Materials and Methods: Resistance measurements were obtained from 12 pedicle screw varieties (6 screws of each manufacturer) across the screw shank based on known constant current and measured voltage. The voltage was measured 5 times at each site. Results: Resistance of all solid screws ranged from 0.084 ? to 0.151 ? (mean =0.118 ± 0.024 ?) and hollow screws ranged from 0.148 ? to 0.402 ? (mean = 0.285 ± 0.081 ?). There was a significant difference of resistance between the solid screws and hollow screws (P < 0.05). The screw with the largest diameter no matter solid screws or hollow screws had lower resistance than screws with other diameters. No matter in solid screws group or hollow screws group, there were significant differences (P < 0.05) between the 5.0 mm screws and 6.0 mm screws, 6.0 mm screws and 7.0 mm screws, 5.0 mm screws and 7.0 mm screws, 4.5 mm screws and 5.5 mm screws, 5.5 mm screws and 6.5 mm screws, 4.5 mm screws and 6.5 mm screws. The resistance of hollow screws was much larger than the solid screws in the same diameter group (P < 0.05). Conclusions: Hollow pedicle screws have the potential for high electrical resistance compared to the solid pedicle screws and therefore may affect the EMG response during stimulus-evoked EMG testing in pedicle screw fixation especially in minimally invasive percutaneous pedical screw fixation surgery. PMID:23960278

Wang, Hongwei; Liao, Xinhua; Ma, Xianguang; Li, Changqing; Han, Jianda; Zhou, Yue

2013-01-01

390

Motor-Evoked Potential Confirmation of Functional Improvement by Transplanted Bone Marrow Mesenchymal Stem Cell in the Ischemic Rat Brain  

PubMed Central

This study investigated the effect of bone marrow mesenchymal stem cells (BMSCs) on the motor pathway in the transient ischemic rat brain that were transplanted through the carotid artery, measuring motor-evoked potential (MEP) in the four limbs muscle and the atlantooccipital membrane, which was elicited after monopolar and bipolar transcortical stimulation. After monopolar stimulation, the latency of MEP was significantly prolonged, and the amplitude was less reduced in the BMSC group in comparison with the control group (P < .05). MEPs induced by bipolar stimulation in the left forelimb could be measured in 40% of the BMSC group and the I wave that was not detected in the control group was also detected in 40% of the BMSC group. Our preliminary results imply that BMSCs transplanted to the ischemic rat brain mediate effects on the functional recovery of the cerebral motor cortex and the motor pathway. PMID:21772790

Jang, Dong-Kyu; Park, Sang-In; Han, Young-Min; Jang, Kyung-Sool; Park, Moon-Seo; Chung, Young-An; Kim, Min-Wook; Maeng, Lee-So; Huh, Pil-Woo; Yoo, Do-Sung; Jung, Seong-Whan

2011-01-01

391

Continuous somatosensory evoked potentials monitoring is highly sensitive to intraoperative occlusion of iliac artery during anterior lumbar interbody fusion: case report.  

PubMed

We report a case of thrombotic occlusion of the left common iliac artery during an L5-S1 anterior interbody fusion exposed via a retroperitoneal approach. The loss of distal blood flow was detected by loss of cortical and peripheral somatosensory evoked potentials on the left lower extremity. Restoration of the blood flow resulted in gradual return of evoked potentials of the involved extremity. The neurophysiological and pulse oximetry monitoring of the lower extremities are extremely sensitive for an early detection of thrombotic occlusions and vascular complications. PMID:19694209

Haghighi, S S; Zhang, R; Raiszadeh, R; Chammas, J; Bench, G; Raiszadeh, K; Terramanis, T T

2009-01-01

392

Dose and timing effect of etomidate on motor evoked potentials elicited by transcranial electric or magnetic stimulation in the monkey and baboon  

Microsoft Academic Search

Objective  Etomidate has been shown to both enhance and depress the cortical amplitude of somatosensory evoked potentials (SSEP) depending\\u000a on the dose used. Similar amplitude increases with etomidate and motor evoked potentials resulting from cortical magnetic\\u000a (tcMMEP) and electric (tcEMEP) stimulation have not been consistent. We used a primate model to elucidate the time and dose\\u000a characteristics of the effect.\\u000a \\u000a \\u000a \\u000a Methods  

Tod Sloan; J. Rogers

2009-01-01

393

Benchmark dose calculations for methylmercury-associated delays on evoked potential latencies in two cohorts of children.  

PubMed

Delays in evoked potential latencies were observed at increased exposures to methylmercury from seafood in two cohorts of children. Because this outcome parameter appeared to be virtually independent of confounders, including cultural differences, a joint analysis of benchmark doses was carried out. Comparable cohort members included 382 Faroese and 113 Madeiran children without middle ear infection or neurological disease at age seven years. Maternal hair-mercury concentrations at parturition in the Faroese cohort ranged from 0.6 to 39.1 microg/g (geometric average, 4.49 microg/g). In Madeira, mothers who had not changed their diet since pregnancy had current hair-mercury concentrations ranging from 1.1 to 54.4 microg/g (geometric average 10.14 microg/g). The mercury-associated delay in peak III latencies at two frequencies (20 and 40 Hz) showed similar regression equations in the two groups of children, and benchmark dose calculations were therefore carried out for the two groups separately and jointly. For a doubling of a 5% prevalence of abnormal results of the peak III latencies at 40 Hz in a linear dose-response model, the benchmark dose for the maternal hair-mercury concentration was 8.79 microg/g for the Faroese children; 8.04 microg/g for the Madeiran children; and 9.46 microg/g for both groups. Results were similar for the 20 Hz condition. Benchmark dose results were substantially lower using a logarithmic or square root curve function, although the difference in fit between the curves was far from statistically significant. The benchmark results using evoked potential latencies are in close agreement with results based on neuropsychological test performance. PMID:12088226

Murata, Katsuyuki; Budtz-Jørgensen, Esben; Grandjean, Philippe

2002-06-01

394

Effects of dimethylarsinic and dimethylarsinous acid on evoked synaptic potentials in hippocampal slices of young and adult rats  

SciTech Connect

In this study, the effects of pentavalent dimethylarsinic acid ((CH{sub 3}){sub 2}AsO(OH); DMA{sup V}) and trivalent dimethylarsinous acid ((CH{sub 3}){sub 2}As(OH); DMA{sup III}) on synaptic transmission generated by the excitatory Schaffer collateral-CA1 synapse were tested in hippocampal slices of young (14-21 day-old) and adult (2-4 month-old) rats. Both compounds were applied in concentrations of 1 to 100 {mu}mol/l. DMA{sup V} had no effect on the amplitudes of evoked fEPSPs or the induction of LTP recorded from the CA1 dendritic region either in adult or in young rats. However, application of DMA{sup III} significantly reduced the amplitudes of evoked fEPSPs in a concentration-dependent manner with a total depression following application of 100 {mu}mol/l DMA{sup III} in adult and 10 {mu}mol/l DMA{sup III} in young rats. Moreover, DMA{sup III} significantly affected the LTP-induction. Application of 10 {mu}mol/l DMA{sup III} resulted in a complete failure of the postsynaptic potentiation of the fEPSP amplitudes in slices taken both from adult and young rats. The depressant effect was not reversible after a 30-min washout of the DMA{sup III}. In slices of young rats, the depressant effects of DMA{sup III} were more pronounced than in those taken from adult ones. Compared to the (absent) effect of DMA{sup V} on synaptic transmission, the trivalent compound possesses a considerably higher neurotoxic potential.

Krueger, Katharina [Institut fuer Physiologie I, Universitaetsklinikum Muenster, Robert-Koch-Strasse 27a, D-48149 Muenster (Germany)], E-mail: katharina.krueger@uni-muenster.de; Repges, Hendrik [Institut fuer Physiologie I, Universitaetsklinikum Muenster, Robert-Koch-Strasse 27a, D-48149 Muenster (Germany); Hippler, Joerg; Hartmann, Louise M.; Hirner, Alfred V. [Institut fuer Umweltanalytik, Universitaet Duisburg-Essen, Universitaetsstrasse 3-5, D-45141 Essen (Germany); Straub, Heidrun [Institut fuer Physiologie I, Universitaetsklinikum Muenster, Robert-Koch-Strasse 27a, D-48149 Muenster (Germany); Binding, Norbert [Institut fuer Arbeitsmedizin, Universitaetsklinikum Muenster, Robert-Koch-Strasse 51, D-48149 Muenster (Germany); Musshoff, Ulrich [Institut fuer Physiologie I, Universitaetsklinikum Muenster, Robert-Koch-Strasse 27a, D-48149 Muenster (Germany)

2007-11-15

395

Frequency tuning of the dolphin's hearing as revealed by auditory brain-stem response with notch-noise masking.  

PubMed

Notch-noise masking was used to measure frequency tuning in a dolphin (Tursiops truncatus) in a simultaneous-masking paradigm in conjunction with auditory brain-stem evoked potential recording. Measurements were made at probe frequencies of 64, 76, 90, and 108 kHz. The data were analyzed by fitting the rounded-exponent model of the auditory filters to the experimental data. The fitting parameter values corresponded to the filter tuning as follows: QER (center frequency divided by equivalent rectangular bandwidths) of 35 to 36.5 and Q10 dB of 18 to 19 at all tested frequencies. PMID:9407671

Popov, V V; Supin, A Y; Klishin, V O

1997-12-01

396

Please cite this article in press as: J.Q. Wang, et al., Emotion and the auditory brainstem response to speech, Neurosci. Lett. (2009), doi:10.1016/j.neulet.2009.12.018  

E-print Network

Please cite this article in press as: J.Q. Wang, et al., Emotion and the auditory brainstemDirect Neuroscience Letters journal homepage: www.elsevier.com/locate/neulet Emotion and the auditory brainstem Keywords: Emotion Auditory brainstem response Speech IAPS EEG Evoked response a b s t r a c t Effects

Kraus, Nina

397

DownloadedBy:[NorthwesternUniversity]At:14:157September2007 Karen Banai*,$  

E-print Network

Speech encoding Abbreviations AEP: Auditory-evoked potentials ABR: Auditory brainstem response FFR disability: Insights from brainstem processing of speech sounds Abstract Speech-evoked auditory brainstem

398

Effects of the brominated flame retardant hexabromocyclododecane (HBCD) on dopamine-dependent behavior and brainstem auditory evoked potentials in a one-generation reproduction study in Wistar rats  

Microsoft Academic Search

Hexabromocyclododecane (HBCD) is a widely used brominated flame retardant which has been recently detected in many environmental matrices. Data from a subacute toxicity study indicated dose-related effects particularly on the pituitary thyroid-axis and retinoids in female rats. Brominated and chlorinated aromatic hydrocarbons are also reported to exert effects on the nervous system. Several investigations revealed a pronounced sensitivity of the

Hellmuth Lilienthal; Aldert H. Piersma; Josephus G. Vos

2009-01-01

399

INHALATIONAL EXPOSURE TO CARBONYL SULFIDE (COS) PRODUCES BRAIN LESIONS AND ALTERED BRAINSTEM AUDITORY (BAER) AND SOMATOSENSORY (SEP) EVOKED POTENTIALS IN FISHCER 344N RATS.  

EPA Science Inventory

Because of the amount of carbonyl sulfide (COS) emissions and the lack of toxicological data, COS was listed in the Clean Air Act of 1990 as a Hazardous Air Pollutant. In 1999 COS was nominated by the US EPA to the National Toxicology Program for additional toxicological investig...

400

12 WEEK EXPOSURE TO CARBONYL SULFIDE PRODUCES BRAIN LESIONS AND CHANGES IN BRAINSTEM AUDITORY (BAER) AND SOMATOSENAORY (SEP) EVOKED POTENTIALS IN FISCHER 344N RATS  

EPA Science Inventory

Carbonyl sulfide (COS) is a chemical intermediate in the production of pesticides and herbicides, is a metabolite of carbon disulfide, is produced by the combustion of organic material, and is found occurring in nature. COS was included in a Toxic Substances Control Act request f...

401

Source analysis of short and long latency vestibular-evoked potentials (VsEPs) produced by left vs. right ear air-conducted 500 Hz tone pips.  

PubMed

Todd et al. (2014) have recently demonstrated the presence of vestibular dependent changes both in the morphology and in the intensity dependence of auditory evoked potentials (AEPs) when passing through the vestibular threshold as determined by vestibular evoked myogenic potentials (VEMPs). In this paper we extend this work by comparing left vs. right ear stimulation and by conducting a source analysis of the resulting evoked potentials of short and long latency. Ten healthy, right-handed subjects were recruited and evoked potentials were recorded to both left- and right-ear sound stimulation, above and below vestibular threshold. Below VEMP threshold, typical AEPs were recorded, consisting of mid-latency (MLR) waves Na and Pa followed by long latency AEPs (LAEPs) N1 and P2. In the supra-threshold condition, the expected changes in morphology were observed, consisting of: (1) short-latency vestibular evoked potentials (VsEPs) which have no auditory correlate, i.e. the ocular VEMP (OVEMP) and inion response related potentials; (2) a later deflection, labelled N42/P52, followed by the LAEPs N1 and P2. Statistical analysis of the vestibular dependent responses indicated a contralateral effect for inion related short-latency responses and a left-ear/right-hemisphere advantage for the long-latency responses. Source analysis indicated that the short-latency effects may be mediated by a contralateral projection to left cerebellum, while the long-latency effects were mediated by a contralateral projection to right cingulate cortex. In addition we found evidence of a possible vestibular contribution to the auditory T-complex in radial temporal lobe sources. These last results raise the possibility that acoustic activation of the otolith organs could potentially contribute to auditory processing. PMID:24699384

Todd, N P M; Paillard, A C; Kluk, K; Whittle, E; Colebatch, J G

2014-06-01

402

Source analysis of short and long latency vestibular-evoked potentials (VsEPs) produced by left vs. right ear air-conducted 500 Hz tone pips  

PubMed Central

Todd et al. (2014) have recently demonstrated the presence of vestibular dependent changes both in the morphology and in the intensity dependence of auditory evoked potentials (AEPs) when passing through the vestibular threshold as determined by vestibular evoked myogenic potentials (VEMPs). In this paper we extend this work by comparing left vs. right ear stimulation and by conducting a source analysis of the resulting evoked potentials of short and long latency. Ten healthy, right-handed subjects were recruited and evoked potentials were recorded to both left- and right-ear sound stimulation, above and below vestibular threshold. Below VEMP threshold, typical AEPs were recorded, consisting of mid-latency (MLR) waves Na and Pa followed by long latency AEPs (LAEPs) N1 and P2. In the supra-threshold condition, the expected changes in morphology were observed, consisting of: (1) short-latency vestibular evoked potentials (VsEPs) which have no auditory correlate, i.e. the ocular VEMP (OVEMP) and inion response related potentials; (2) a later deflection, labelled N42/P52, followed by the LAEPs N1 and P2. Statistical analysis of the vestibular dependent responses indicated a contralateral effect for inion related short-latency responses and a left-ear/right-hemisphere advantage for the long-latency responses. Source analysis indicated that the short-latency effects may be mediated by a contralateral projection to left cerebellum, while the long-latency effects were mediated by a contralateral projection to right cingulate cortex. In addition we found evidence of a possible vestibular contribution to the auditory T-complex in radial temporal lobe sources. These last results raise the possibility that acoustic activation of the otolith organs could potentially contribute to auditory processing. PMID:24699384

Todd, N.P.M.; Paillard, A.C.; Kluk, K.; Whittle, E.; Colebatch, J.G.

2014-01-01

403

Enhancement of Auditory-evoked Potentials in Musicians Reflects an Influence of Expertise but not Selective Attention  

Microsoft Academic Search

Instrumental tones and, in some instances, simple sine-wave tones were shown to evoke stronger auditory-evoked responses in musicians compared to nonmusicians. This effect was taken as an example for plasticity in the auditory cortex elicited by training. To date, however, it is unknown whether an enlarged cortical representation for (instrumental) tones or increased neuronal activity provoked by focused attention in

Simon Baumann; Martin Meyer; Lutz Jäncke

2008-01-01

404

Sensory evoked potentials in unanesthetized unrestrained cuttlefish: a new preparation for brain physiology in cephalopods  

Microsoft Academic Search

Up to five microelectrodes inserted through short hypodermic needles in the cranial cartilage of Sepia officinalis recorded potentials while the cuttlefish moved freely in a small enclosure. Compound field potentials and unit spikes were seen during ongoing, spontaneous activity and after sensory stimulation.

Theodore H. Bullock; Bernd U. Budelmann

1991-01-01

405

DEPRESSION OF THE PHOTIC AFTER DISCHARGE OF FLASH EVOKED POTENTIALS BY PHYSOSTIGMINE, CARBARYL AND PROPOXUR AND THE RELATIONSHIP TO INHIBITION OF BRAIN CHOLINESTERASE  

EPA Science Inventory

The effects of N-methyl carbamate pesticides on the photic after discharge (PhAD) of flash evoked potentials (FEPs) and the relationship between inhibition of brain cholinesterase (ChE) activity and the PhAD were evaluated. FEPs were recorded in Long Evans rats treated with physo...

406

Brain Dynamics of Scalp Evoked Potentials and Current Source Densities to Repetitive (5-pulse Train) Painful Stimulation of Skin and Muscle: Central Correlate of Temporal Summation  

Microsoft Academic Search

Temporal summation is a potent central somatosensory mechanism and may be a major mechanism involved in e.g. neuropathic pain. This study assessed the long-latency somatosensory evoked potentials (SEPs) in response to trains of repeated painful electrical stimulation of human skin and muscle in order to investigate the cerebral representation of temporal summation. Forty series of stimuli were delivered at stimulus

Andrew C. N. Chen; Motoko Shimojo; Peter Svensson; Lars Arendt-Nielsen

2000-01-01

407

Acoustic-electric interactions in the guinea pig auditory nerve: Simultaneous and forward masking of the electrically evoked compound action potential  

Microsoft Academic Search

The study investigated the time course of the effects of acoustic and electric stimulation on the electrically evoked compound action potential (ECAP). Adult guinea pigs were used in acute experimental sessions. Bursts of acoustic noise and high-rate (5000 pulses\\/s) elec- tric pulse trains were used as maskers. Biphasic electric pulses were used as probes. ECAPs were recorded from the auditory

Kirill V. Nourski; Paul J. Abbas; Charles A. Miller; Barbara K. Robinson; Fuh-Cherng Jeng

2007-01-01

408

Effects of ketamine and propofol on motor evoked potentials elicited by intracranial microstimulation during deep brain stimulation  

PubMed Central

Few preclinical or clinical studies have evaluated the effect of anesthetics on motor evoked potentials (MEPs), either alone or in the presence of conditioning stimuli such as deep brain stimulation (DBS). In this study we evaluated the effects of two commonly used anesthetic agents, propofol and ketamine (KET), on MEPs elicited by intra-cortical microstimulation of the motor cortex in a rodent model with and without DBS of the dentatothalamocortical (DTC) pathway. The effects of propofol anesthesia on MEP amplitudes during DTC DBS were found to be highly dose dependent. Standard, but not high, dose propofol potentiated the facilitatory effects of 30 Hz DTC DBS on MEPs. This facilitation was sustained and phase-dependent indicating that, compared to high dose propofol, standard dose propofol has a beta-band excitatory effect on cortical networks. In contrast, KET anesthetic demonstrated a monotonic relationship with increasing frequencies of stimulation, such that the highest frequency of stimulation resulted in the greatest MEP amplitude. KET also showed phase dependency but less pronounced than standard dose propofol. The results underscore the importance of better understanding the complex effects of anesthetics on cortical networks and exogenous stimuli. Choice of anesthetic agents and dosing may significantly confound or even skew research outcomes, including experimentation in novel DBS indications and paradigms. PMID:24904312

Furmaga, Havan; Park, Hyun-Joo; Cooperrider, Jessica; Baker, Kenneth B.; Johnson, Matthew; Gale, John T.; Machado, Andre G.

2014-01-01

409

Odor-evoked oxygen consumption by action potential and synaptic transmission in the olfactory bulb  

PubMed Central

The relationship between metabolism of neuronal activity, microvascular organization and blood flow dynamics is critical for interpreting functional brain imaging. Here we used the rat dorsal olfactory bulb as a model to determine in vivo the correlation between action potential propagation, synaptic transmission, oxygen consumption and capillary density during odor stimulation. We find that capillary lumen occupies about 3 % of the glomerular volume, where synaptic transmission occurs, and only 0.1 % of the overlying nerve layer. In glomeruli, odor triggers a local early decrease in tissue oxygen partial pressure that results principally from dendritic activation rather than from firing of axon terminals, transmitter release or astrocyte activation. In the nerve layer, action potential propagation does not generate local changes in tissue oxygen partial pressure. We conclude that capillary density is tightly correlated with the oxidative metabolism of synaptic transmission, and suggest that action potential propagation operates mainly anaerobically. PMID:19193889

Lecoq, Jérôme; Tiret, Pascale; Najac, Marion; Shepherd, Gordon M.; Greer, Charles A.; Charpak, Serge

2009-01-01

410

House dust mite potentiates capsaicin-evoked Ca2+ transients in mouse pulmonary sensory neurons via activation of protease-activated receptor-2  

PubMed Central

House dust mite (HDM) is a major source of allergen in house dust and has been suggested to be involved in the pathogenesis of asthma. In this study, we aimed to investigate whether HDM can modulate the sensitivity of pulmonary sensory neurons, and if so, to elucidate the underlying mechanism. Fura-2 based ratiometric Ca2+ imaging was carried out to determine the effect of HDM extract on the capsaicin-evoked Ca2+ transient in mouse vagal pulmonary sensory neurons. Pretreatment with HDM (50 ?g/ml, 5 min) significantly enhanced the Ca2+ transient evoked by capsaicin in these neurons isolated from wildtype mice. This potentiating effect of HDM was not antagonized by E-64, a selective cysteine protease inhibitor, but was completely prevented by AEBSF, a specific serine protease inhibitor. In addition, the potentiating effect of HDM on capsaicin-evoked Ca2+ transient was absent in the pulmonary sensory neurons isolated from protease-activated receptor-2 (PAR2) knockout mice. Further, the sensitizing effect of HDM was completely abolished by U73122, a PLC inhibitor, or chelerythrine, a PKC inhibitor. In summary, our results demonstrate that HDM, mainly through its serine protease activity, potentiates capsaicin-evoked Ca2+ transient in mouse pulmonary sensory neurons via the activation of PAR2 and PLC-PKC intracellular transduction cascade. PMID:22125310

Gu, Qihai; Lee, Lu-Yuan

2011-01-01

411

Na+ imaging reveals little difference in action potential–evoked Na+ influx between axon and soma  

Microsoft Academic Search

In cortical pyramidal neurons, the axon initial segment (AIS) is pivotal in synaptic integration. It has been asserted that this is because there is a high density of Na+ channels in the AIS. However, we found that action potential–associated Na+ flux, as measured by high-speed fluorescence Na+ imaging, was about threefold larger in the rat AIS than in the soma.

Nechama Lasser-Ross; Michael J Gutnick; William N Ross; Ilya A Fleidervish

2010-01-01

412

Visual Perception and Frontal Lobe in Intellectual Disabilities: A Study with Evoked Potentials and Neuropsychology  

ERIC Educational Resources Information Center

Background: Perception disorders are frequently observed in persons with intellectual disability (ID) and their influence on cognition has been discussed. The objective of this study is to clarify the mechanisms behind these alterations by analysing the visual event related potentials early component, the N1 wave, which is related to perception…

Munoz-Ruata, J.; Caro-Martinez, E.; Perez, L. Martinez; Borja, M.

2010-01-01

413

Auditory evoked responses to rhythmic sound pulses in dolphins.  

PubMed

The ability of auditory evoked potentials to follow sound pulse (click or pip) rate was studied in bottlenosed dolphins. Sound pulses were presented in 20-ms rhythmic trains separated by 80-ms pauses. Rhythmic click or pip trains evoked a quasi-sustained response consisting of a sequence of auditory brainstem responses. This was designated as the rate-following response. Rate following response peak-to-peak amplitude dependence on sound pulse rate was almost flat up to 200 s-1, then displayed a few peaks and valleys superimposed on a low-pass filtering function with a cut-off frequency of 1700 s-1 at a 0.1-amplitude level. Peaks and valleys of the function corresponded to the pattern of the single auditory brain stem response spectrum; the low-pass cut-off frequency was below the auditory brain stem response spectrum bandwidth. Rate-following response frequency composition (magnitudes of the fundamental and harmonics) corresponded to the auditory brain stem response frequency spectrum except for lower fundamental magnitudes at frequencies above 1700 Hz. These regularities were similar for both click and pip trains. The rate-following response to steady-state rhythmic stimulation was similar to the rate-following response evoked by short trains except for a slight amplitude decrease with the rate increase above 10 s-1. The latter effect is attributed to a long-term rate-dependent adaptation in conditions of the steady-state pulse stimulation. PMID:9809455

Popov, V V; Supin, A Y

1998-10-01

414

Properties of Ca2+ sparks evoked by action potentials in mouse ventricular myocytes  

PubMed Central

Calcium sparks were examined in enzymatically dissociated mouse cardiac ventricular cells using the calcium indicator fluo-3 and confocal microscopy. The properties of the mouse cardiac calcium spark are generally similar to those reported for other species.Examination of the temporal relationship between the action potential and the time course of calcium spark production showed that calcium sparks are more likely to occur during the initial repolarization phase of the action potential. The latency of their occurrence varied by less than 1·4 ms (s.d.) and this low variability may be explained by the interaction of the gating of L-type calcium channels with the changes in driving force for calcium entry during the action potential.When fixed sites within the cell are examined, calcium sparks have relatively constant amplitude but the amplitude of the sparks was variable among sites. The low variability of the amplitude of the calcium sparks suggests that more than one sarcoplasmic reticulum (SR) release channel must be involved in their genesis. Noise analysis (with the assumption of independent gating) suggests that > 18 SR calcium release channels may be involved in the generation of the calcium spark. At a fixed site, the response is close to ‘all-or-none’ behaviour which suggests that calcium sparks are indeed elementary events underlying cardiac excitation-contraction coupling.A method for selecting spark sites for signal averaging is presented which allows the time course of the spark to be examined with high temporal and spatial resolution. Using this method we show the development of the calcium spark at high signal-to-noise levels. PMID:10381593

Bridge, John H B; Ershler, Philip R; Cannell, Mark B

1999-01-01

415

Reduced probability of orthodromically evoked action potential firing in CA1 pyramidal cellof guinea pig hippocampal slices after acute thallium exposure  

Microsoft Academic Search

We investigated the effect of thallium ions on extracellular field potentials in the CA1 region of guinea pig hippocampal\\u000a slices in a matched-pair experimental setup. Somatic and dendritic responses evoked by paired-pulse stimulation of the Schaffer\\u000a collateral-commissural pathway were recorded before, during and after acute thallium exposure and compared to field potentials\\u000a from nontreated control slices recorded simultaneously. Thallium reduced

Horst Lohmann; Herbert Wiegand

1996-01-01

416

Frequency-doubling technology perimetry and multifocal visual evoked potential in glaucoma, suspected glaucoma, and control patients  

PubMed Central

Introduction The gold standard in functional glaucoma evaluation is standard automated perimetry (SAP). However, SAP depends on the reliability of the patients’ responses and other external factors; therefore, other technologies have been developed for earlier detection of visual field changes in glaucoma patients. The frequency-doubling perimetry (FDT) is believed to detect glaucoma earlier than SAP. The multifocal visual evoked potential (mfVEP) is an objective test for functional evaluation. Objective To evaluate the sensitivity and specificity of FDT and mfVEP tests in normal, suspect, and glaucomatous eyes and compare the monocular and interocular mfVEP. Methods Ninety-five eyes from 95 individuals (23 controls, 33 glaucoma suspects, 39 glaucomatous) were enrolled. All participants underwent a full ophthalmic examination, followed by SAP, FDT, and mfVEP tests. Results The area under the curve for mean deviation and pattern standard deviation were 0.756 and 0.761, respectively, for FDT, 0.564 and 0.512 for signal and alpha for interocular mfVEP, and 0.568 and 0.538 for signal and alpha for monocular mfVEP. This difference between monocular and interocular mfVEP was not significant. Conclusion The FDT Matrix was superior to mfVEP in glaucoma detection. The difference between monocular and interocular mfVEP in the diagnosis of glaucoma was not significant. PMID:25075173

Kanadani, Fabio N; Mello, Paulo AA; Dorairaj, Syril K; Kanadani, Tereza CM

2014-01-01

417

Generating Visual Flickers for Eliciting Robust Steady-State Visual Evoked Potentials at Flexible Frequencies Using Monitor Refresh Rate  

PubMed Central

In the study of steady-state visual evoked potentials (SSVEPs), it remains a challenge to present visual flickers at flexible frequencies using monitor refresh rate. For example, in an SSVEP-based brain-computer interface (BCI), it is difficult to present a large number of visual flickers simultaneously on a monitor. This study aims to explore whether or how a newly proposed frequency approximation approach changes signal characteristics of SSVEPs. At 10 Hz and 12 Hz, the SSVEPs elicited using two refresh rates (75 Hz and 120 Hz) were measured separately to represent the approximation and constant-period approaches. This study compared amplitude, signal-to-noise ratio (SNR), phase, latency, scalp distribution, and frequency detection accuracy of SSVEPs elicited using the two approaches. To further prove the efficacy of the approximation approach, this study implemented an eight-target BCI using frequencies from 8–15 Hz. The SSVEPs elicited by the two approaches were found comparable with regard to all parameters except amplitude and SNR of SSVEPs at 12 Hz. The BCI obtained an averaged information transfer rate (ITR) of 95.0 bits/min across 10 subjects with a maximum ITR of 120 bits/min on two subjects, the highest ITR reported in the SSVEP-based BCIs. This study clearly showed that the frequency approximation approach can elicit robust SSVEPs at flexible frequencies using monitor refresh rate and thereby can largely facilitate various SSVEP-related studies in neural engineering and visual neuroscience. PMID:24918435

Nakanishi, Masaki; Wang, Yijun; Wang, Yu-Te; Mitsukura, Yasue; Jung, Tzyy-Ping

2014-01-01

418

Auditory evoked potential measurement methodology for odontocetes and a comparison of measured thresholds with those obtained using psychophysical techniques  

NASA Astrophysics Data System (ADS)

Most measurements of the hearing capabilities of toothed whales and dolphins have been taken using traditional psychophysical procedures in which the animals have been maintained in laboratory environments and trained to behaviorally report the sensation or difference of acoustic stimuli. Because of the advantage of rapid data collection, increased opportunities, and new methods, Auditory Evoked Potentials (AEPs) have become increasingly used to measure audition. The use of this new procedure calls to question the comparability of the established literature and the new results collected with AEPs. The results of behavioral and AEP methods have been directly compared with basic audiogram measurements and have been shown to produce similar (but not exactly the same) values when the envelope following response procedure has been used and the length of the stimulus is taken into account. The AEP methods allow possible audiometric opportunities beyond those available with conventional psychophysics including: (1) the measurement of stranded dolphins and whales that may never be kept in laboratories, (2) the testing of stranded animals for hearing deficits perhaps caused by overexposure to noise, and (3) passive testing of hearing mechanisms while animals actively echolocate. [Work supported by the Office of Naval Research and NOAA-NMFS.

Nachtigall, Paul E.; Yuen, Michelle; Mooney, T. Aran; Taylor, Kristen

2005-04-01

419

Underwater hearing in the loggerhead turtle (Caretta caretta): a comparison of behavioral and auditory evoked potential audiograms.  

PubMed

The purpose of this study was to compare underwater behavioral and auditory evoked potential (AEP) audiograms in a single captive adult loggerhead sea turtle (Caretta caretta). The behavioral audiogram was collected using a go/no-go response procedure and a modified staircase method of threshold determination. AEP thresholds were measured using subdermal electrodes placed beneath the frontoparietal scale, dorsal to the midbrain. Both methods showed the loggerhead sea turtle to have low frequency hearing with best sensitivity between 100 and 400 Hz. AEP testing yielded thresholds from 100 to 1131 Hz with best sensitivity at 200 and 400 Hz (110 dB re. 1 ?Pa). Behavioral testing using 2 s tonal stimuli yielded underwater thresholds from 50 to 800 Hz with best sensitivity at 100 Hz (98 dB re. 1 ?Pa). Behavioral thresholds averaged 8 dB lower than AEP thresholds from 100 to 400 Hz and 5 dB higher at 800 Hz. The results suggest that AEP testing can be a good alternative to measuring a behavioral audiogram with wild or untrained marine turtles and when time is a crucial factor. PMID:22875768

Martin, Kelly J; Alessi, Sarah C; Gaspard, Joseph C; Tucker, Anton D; Bauer, Gordon B; Mann, David A

2012-09-01

420

Objective assessment of visual attention in mild traumatic brain injury (mTBI) using visual-evoked potentials (VEP).  

PubMed

Abstract Purpose: To quantify visual attention objectively using the visual-evoked potential (VEP) in those having mild traumatic brain injury (mTBI) with and without a self-reported attentional deficit. Research design and methods: Subjects were comprised of 16 adults with mTBI: 11 with an attentional deficit and five without. Three test conditions were used to assess the visual attentional state to quantify objectively the VEP alpha band attenuation ratio (AR) related to attention: (1) pattern VEP; (2) eyes-closed; and (3) eyes-closed number counting. The AR was calculated for both the individual and combined alpha frequencies (8-13?Hz). The objective results were compared to two subjective tests of visual and general attention (i.e. the VSAT and ASRS, respectively). Results: The AR for both the individual and combined alpha frequencies was found to be abnormal in those with mTBI having an attentional deficit. In contrast, the AR was normal in those with mTBI but without an attentional deficit. The AR correlated with the ASRS, but not with the VSAT, test scores. Conclusions: The objective and subjective tests were able to differentiate between those having mTBI with and without an attentional deficit. The proposed VEP protocol can be used in the clinic to detect and assess objectively and reliably a visual attentional deficit in the mTBI population. PMID:25415539

Yadav, Naveen K; Ciuffreda, Kenneth J

2014-11-21

421

The interaction of outgoing echolocation pulses and echoes in the false killer whale's auditory system: evoked-potential study.  

PubMed

Brain auditory evoked potentials (AEP) associated with echolocation were recorded in a false killer whale Pseudorca crassidens trained to accept suction-cup EEG electrodes and to detect targets by echolocation. AEP collection was triggered by echolocation pulses transmitted by the animal. The target was a hollow aluminum cylinder of strength of -22 dB at a distance from 1 to 8 m. Each AEP record was obtained by averaging more than 1000 individual records. All the records contained two AEP sets: the first one of a constant latency and a second one with a delay proportional to the distance. The timing of these two AEP sets was interpreted as responses to the transmitted echolocation pulse and echo, respectively. The echo-related AEP, although slightly smaller, was comparable to the outgoing click-related AEP in amplitude, even though at a target distance as far as 8 m the echo intensity was as low as -64 dB relative to the transmitted pulse in front of the head. The amplitude of the echo-related AEP was almost independent of distance, even though variation of target distance from 1 to 8 m influenced the echo intensity by as much as 36 dB. PMID:15237846

Supin, Alexander Ya; Nachtigall, Paul E; Au, Whitlow W L; Breese, Marlee

2004-06-01

422

Interaction of emitted sonar pulses and simulated echoes in a false killer whale: an evoked-potential study.  

PubMed

Auditory evoked potentials (AEP) were recorded during echolocation in a false killer whale Pseudorca crassidens. An electronically synthesized and played-back (simulated) echo was triggered by an emitted biosonar pulse, and its intensity was proportional to that of the emitted click. The delay and transfer factor of the echo relative to the emitted click was controlled by the operator. The echo delay varied from 2 to 16 ms (by two-fold steps), and the transfer factor varied within ranges from -45 to -30 dB at the 2-ms delay to -60 to -45 dB at the 16-ms delay. Echo-related AEPs featured amplitude dependence both on echo delay at a constant transfer factor (the longer the delay, the higher amplitude) and on echo transfer factor at a constant delay (the higher transfer factor, the higher amplitude). Conjunctional variation of the echo transfer factor and delay kept the AEP amplitude constant when the delay to transfer factor trade was from -7.1 to -8.4 dB per delay doubling. The results confirm the hypothesis that partial forward masking of the echoes by the preceding emitted sonar pulses serves as a time-varying automatic gain control in the auditory system of echolocating odontocetes. PMID:21895108

Supin, Alexander Ya; Nachtigall, Paul E; Breese, Marlee

2011-09-01

423

Invariance of evoked-potential echo-responses to target strength and distance in an echolocating false killer whale.  

PubMed

Brain auditory evoked potentials (AEPs) were recorded in a false killer whale Pseudorca crassidens trained to accept suction-cup EEG electrodes and to detect targets by echolocation. AEP collection was triggered by echolocation pulses transmitted by the animal. The target strength varied from -22 to -40 dB; the distance varied from 1.5 to 6 m. All the records contained two AEP sets: the first one of a constant latency (transmission-related AEP) and a second one with a delay proportional to the distance (echo-related AEP). The amplitude of echo-related AEPs was almost independent of both target strength and distance, though combined variation of these two parameters resulted in echo intensity variation within a range of 42 dB. The amplitude of transmission-related AEPs was independent of distance but dependent on target strength: the less the target strength, the higher the amplitude. Recording of transmitted pulses has not shown their intensity dependence on target strength. It is supposed that the constancy of echo-related AEP results from variation of hearing sensitivity depending on the target strength and release of echo-related responses from masking by transmitted pulses depending on the distance. PMID:16018494

Supin, Alexander Ya; Nachtigall, Paul E; Au, Whitlow W L; Breese, Marlee

2005-06-01

424

Visual evoked potentials (VEP) evaluating treatment for post-trauma vision syndrome (PTVS) in patients with traumatic brain injuries (TBI)  

PubMed

Post-trauma vision syndrome (PTVS), which is characterized by binocular function problems, may be caused by dysfunction of the ambient visual process which is part of the sensory-motor feedback loop rather than specific oculomotor disturbance. Clinically, PTVS frequently presents with symptoms of diplopia, blur, seeing movement in the spatial environment, vertigo, and hallucination-like experiences. Visual evoked potentials (P100) were used to evaluate an experimental group (n = 10) of subjects who suffered a traumatic brain injury, and a control group (n = 10). A new treatment using prisms and bi-nasal occluders which affected amplitude responses of the VEP was evaluated. The results demonstrate the amplitude of the VEP is a function of cortical binocular integration, and that this is influenced by dysfunction of the ambient visual process. The results also demonstrate that base-in prism and bi-nasal occluders are an effective means to treat ambient vision disturbances resulting from head trauma which causes PTVS. PMID:8193632

Padula, W V; Argyris, S; Ray, J

1994-01-01

425

The effects of xenon on myogenic motor evoked potentials in rabbits: a comparison with propofol and isoflurane.  

PubMed

We compared the effects of xenon on myogenic motor evoked potentials (MEPs) with those of propofol and isoflurane in rabbits under ketamine/fentanyl anesthesia. Thirty animals were randomly allocated to one of 3 groups (n = 10 in each group). In the propofol group, propofol was administered at a rate of 0.4 mg x kg(-1) x min(-1) (small) and 0.8 mg x kg(-1) x min(-1) (large). In the isoflurane group, isoflurane was administered at 0.8% (small) and 1.6% (large). In the xenon group, xenon was administered at 35% (small) and 70% (large). Myogenic MEPs in response to stimulation with single pulse and a train of 5 pulses were recorded from the soleus muscle before, during (at small and large doses), and after the administration of each anesthetic. With single-pulse stimulation, MEPs were recorded in 90% and 50% of animals at small and large doses of xenon, respectively, and MEP amplitudes in the xenon and isoflurane groups were significantly lower compared with those in the propofol group. With train pulse stimulation, MEPs were recorded in 100% and 90% of animals at small and large doses of xenon, respectively, and a reduction in MEP amplitudes by xenon was more prominent than by propofol but less than isoflurane at large doses. These results suggest that MEP recording may be feasible under xenon anesthesia if multipulse stimulation is used, although xenon has suppressive effects on myogenic MEPs. PMID:16717315

Yamamoto, Yuri; Kawaguchi, Masahiko; Kakimoto, Meiko; Takahashi, Masahiro; Inoue, Satoki; Goto, Takahisa; Furuya, Hitoshi

2006-06-01

426

Serotonergic Dysfunction in Patients with Bipolar Disorder Assessed by the Loudness Dependence of the Auditory Evoked Potential  

PubMed Central

Objective The loudness dependence of the auditory evoked potential (LDAEP) is suggested to be a marker of serotonin system function. This study explored the LDAEP of multiple mood statuses (depression, mania, and euthymia) and its clinical implication in bipolar disorder patients. Methods A total of 89 subjects, comprising 35 patients with bipolar disorder, 32 patients with schizophrenia, and 22 healthy controls were evaluated. The bipolar disorder cases comprised 10 depressed patients, 15 patients with mania, and 10 euthymic patients. The N1/P2 peak-to-peak amplitudes were measured at 5 stimulus intensities, and the LDAEP was calculated as the slope of the linear regression. Both cortical and source LDAEP values were calculated. Results LDAEP varied according to mood statuses, and was significantly stronger in cases of euthymia, depression, and mania. Cortical LDAEP was significantly stronger in patients with bipolar euthymia compared with schizophrenia, stronger in bipolar depression than in schizophrenia, stronger in healthy controls than in schizophrenia patients, and stronger in healthy controls than in patients with bipolar mania. Source LDAEP was significantly stronger in patients with bipolar euthymia, bipolar depression, and bipolar mania compared with schizophrenia, stronger in bipolar euthymia than in bipolar mania. Psychotic features weakened the source LDAEP relative to nonpsychotic features. The severity of the depressive symptom was negatively correlated with source LDAEP. Conclusion These findings suggest that the serotonin activity of patients with bipolar disorder may vary according to mood status. A longitudinal follow-up study should be pursued using drug-naive subjects. PMID:22993531

Lee, Kyung-Sang; Park, Young-Min

2012-01-01

427

Update on laser-evoked potential findings in fibromyalgia patients in light of clinical and skin biopsy features.  

PubMed

In fibromyalgia (FM), reduced habituation of laser-evoked potentials (LEPs) suggests a dysfunction of pain processing at a central level. In this study, we aimed to further examine the nociceptive pathways at the peripheral to the central level in a large group of FM patients by means of LEPs and skin biopsy, in light of healthy controls findings and main clinical features. One hundred and ninety-nine FM patients and 109 age- and sex-matched controls were submitted to LEPs by the dorsum of the right hand and the skin over the right chest and knee tender point stimulation. Skin biopsy was performed in 21 randomly selected FM patients and 60 age- and sex-matched controls. The mean N2-P2 amplitude was reduced in the whole FM group, with normal or even increased values in patients with migraine as comorbidity and reduced values in other patients including those presenting with distal sensory deficits. All patients had reduced N2-P2 habituation in respect to controls. In the FM group, LEPs habituation was correlated with pain at tender points and bad quality of life. Epidermal fiber density was significantly reduced in FM patients versus controls, and correlated with N2-P2 amplitude by the hand and chest tender-point stimulation. Dysfunction in the nociceptive system at both the central and peripheral levels may concur to explain phenotypical eterogeneity and clinical symptom complexity in fibromyalgia. PMID:24366650

de Tommaso, Marina; Nolano, Maria; Iannone, Florenzo; Vecchio, Eleonora; Ricci, Katia; Lorenzo, Marta; Delussi, Marianna; Girolamo, Francesco; Lavolpe, Vito; Provitera, Vincenzo; Stancanelli, Annamaria; Lapadula, Giovanni; Livrea, Paolo

2014-03-01

428

Invariance of evoked-potential echo-responses to target strength and distance in an echolocating false killer whale  

NASA Astrophysics Data System (ADS)

Brain auditory evoked potentials (AEPs) were recorded in a false killer whale Pseudorca crassidens trained to accept suction-cup EEG electrodes and to detect targets by echolocation. AEP collection was triggered by echolocation pulses transmitted by the animal. The target strength varied from -22 to -40 dB the distance varied from 1.5 to 6 m. All the records contained two AEP sets: the first one of a constant latency (transmission-related AEP) and a second one with a delay proportional to the distance (echo-related AEP). The amplitude of echo-related AEPs was almost independent of both target strength and distance, though combined variation of these two parameters resulted in echo intensity variation within a range of 42 dB. The amplitude of transmission-related AEPs was independent of distance but dependent on target strength: the less the target strength, the higher the amplitude. Recording of transmitted pulses has not shown their intensity dependence on targ