Effects of ischaemia upon reflex electromyographic responses evoked by stretch and vibration in human wrist flexor muscles.

PubMed Central

Cody, F W; Goodwin, C N; Richardson, H C

1987-01-01

1. The reflex electromyographic responses evoked in a wrist flexor muscle, flexor carpi radialis (f.c.r.), by forcible extension of the wrist ('stretch') and by vibration of the flexor tendon have been studied in normal subjects. Reflexes were elicited during the maintenance of a low level of voluntary flexor contraction (5% maximum). Stretch regularly produced a relatively prolonged (ca. 100 ms duration) increase in e.m.g. activity which was usually divisible into short-latency (ca. 25 ms, M1) and long-latency (ca. 50 ms, M2) peaks. Vibration produced a single, phasic peak, at short latency, with no sign of an accompanying long-latency wave comparable to the M2 stretch response. 2. Ischaemia was induced by inflation of a blood-pressure cuff around the upper arm and its effects upon the reflex patterns were studied. During ischaemia M1 stretch responses showed a more rapid and pronounced decline than did M2 responses and were abolished before voluntary power was appreciably affected. Vibration-evoked short-latency peaks changed in an essentially parallel manner to M1 stretch reflexes. During recovery from ischaemia M2 reflexes were restored before short-latency responses. 3. The patterns of reflex reductions in e.m.g. upon withdrawal of stimulation were also studied. Such troughs in activity, under non-ischaemic conditions, regularly commenced at short latency and were of relatively small amplitude. The records of several of the subjects, and particularly ones obtained during ischaemia, suggested that release of stretch (with concomitant stretch of antagonists) could elicit an additive, long-latency decline in e.m.g. The existence of any such separate, delayed component was never observed upon termination of vibration. 4. Measurements of changes in the latencies and durations of reflex components, accompanying the progression of ischaemia, indicated that depression of early reflex activity resulted in part from increases in the latencies of these initial peaks but predominantly reflected simultaneous and separate reductions in their amplitudes. 5. The generation of short-latency reflexes by stretch and vibration, both of which stimuli powerfully excite muscle spindle primary endings, and the marked susceptibility of these responses to ischaemia supports their being mediated by group Ia afferents. The contrasting behaviour of M2 stretch responses, both regarding their absence with vibration and their resistance to ischaemia, suggests that they depend crucially upon a separate group of reflex afferents.(ABSTRACT TRUNCATED AT 400 WORDS) PMID:3443959

Is There a Relation between Reticular Formation and Storage Symptoms in Men.

PubMed

Zorba, Orhan Ü; Kirbaş, Serkan; Uzun, Hakkı; Önem, Kadir; Çetinkaya, Mehmet; Rifaioğlu, Mehmet M

2014-01-01

To reveal brainstem originated pathology in men with different types of lower urinary tract symptoms blink reflex latency times were assessed. A total of 32 men, 16 with storage and 16 with voiding symptoms, were enrolled in the study. Blink reflex latency times were analyzed through electrical stimulation of the supraorbital nerve. Two responses in the orbicularis oculi muscle were recorded: the latency times for the early ipsilateral response, R1, and the late bilateral responses, R2. The mean ages of the patients with storage and voiding symptoms were 57.31 ± 6.87 and 58.06 ± 6.29 years, respectively. The R2 latency times were significantly longer in men with storage symptoms. However, the R1 latency times were similar for the two groups. Late blink latency times were long only in patients who had storage symptoms. An oligosynaptic path through the trigeminal nuclei, which includes one or two interneurons, is responsible for early response; however, late response is relayed through a polysynaptic path, including neurons in the reticular formation. It has also been shown that stimulation of the pontine reticular formation inhibits the micturition contraction. In some patients, storage symptoms may result from pathology that originates with the reticular formation and this pathology may lead to increases in late blink latency times. Additional studies are needed on other reflexes that are mediated through reticular formation, in order to show the possible dysfunction of the reticular formation in men with storage symptoms. © 2013 Wiley Publishing Asia Pty Ltd.

Relating the variability of tone-burst otoacoustic emission and auditory brainstem response latencies to the underlying cochlear mechanics

NASA Astrophysics Data System (ADS)

Verhulst, Sarah; Shera, Christopher A.

2015-12-01

Forward and reverse cochlear latency and its relation to the frequency tuning of the auditory filters can be assessed using tone bursts (TBs). Otoacoustic emissions (TBOAEs) estimate the cochlear roundtrip time, while auditory brainstem responses (ABRs) to the same stimuli aim at measuring the auditory filter buildup time. Latency ratios are generally close to two and controversy exists about the relationship of this ratio to cochlear mechanics. We explored why the two methods provide different estimates of filter buildup time, and ratios with large inter-subject variability, using a time-domain model for OAEs and ABRs. We compared latencies for twenty models, in which all parameters but the cochlear irregularities responsible for reflection-source OAEs were identical, and found that TBOAE latencies were much more variable than ABR latencies. Multiple reflection-sources generated within the evoking stimulus bandwidth were found to shape the TBOAE envelope and complicate the interpretation of TBOAE latency and TBOAE/ABR ratios in terms of auditory filter tuning.

Anticipation of direction and time of perturbation modulates the onset latency of trunk muscle responses during sitting perturbations.

PubMed

Milosevic, Matija; Shinya, Masahiro; Masani, Kei; Patel, Kramay; McConville, Kristiina M V; Nakazawa, Kimitaka; Popovic, Milos R

2016-02-01

Trunk muscles are responsible for maintaining trunk stability during sitting. However, the effects of anticipation of perturbation on trunk muscle responses are not well understood. The objectives of this study were to identify the responses of trunk muscles to sudden support surface translations and quantify the effects of anticipation of direction and time of perturbation on the trunk neuromuscular responses. Twelve able-bodied individuals participated in the study. Participants were seated on a kneeling chair and support surface translations were applied in the forward and backward directions with and without direction and time of perturbation cues. The trunk started moving on average approximately 40ms after the perturbation. During unanticipated perturbations, average latencies of the trunk muscle contractions were in the range between 103.4 and 117.4ms. When participants anticipated the perturbations, trunk muscle latencies were reduced by 16.8±10.0ms and the time it took the trunk to reach maximum velocity was also reduced, suggesting a biomechanical advantage caused by faster muscle responses. These results suggested that trunk muscles have medium latency responses and use reflexive mechanisms. Moreover, anticipation of perturbation decreased trunk muscles latencies, suggesting that the central nervous system modulated readiness of the trunk based on anticipatory information. Copyright © 2015 Elsevier Ltd. All rights reserved.

Evaluation of the relation between triceps surae H-reflex, M-response latencies and thigh length in normal population.

PubMed

Khosrawi, Saeid; Fallah, Salman

2013-03-01

The H-reflex is a useful electrophysiological procedure for evaluating the status of the peripheral nervous system, especially at the proximal segment of the peripheral nerve. The purpose of this study is to investigate the relation between triceps surae H-reflex and M- response latencies and thigh length in normal population, in order to determine if there is any regression equation between them. After screening 75 volunteers by considering inclusion and exclusion criteria, 72 of them were selected to enroll into our study (34 men and 38 women with the mean age of 36.04 ± 7.7 years). In all of the subjects H-reflex and M-response latencies were recorded by standard electrophysiological techniques and thigh length was measured. Finally, our data was analyzed for its relations with respect to ages in both sexes by appropriate statistical and mathematical methods. Mean ± SD for H-reflex latency was 27.94 ± 1.6 ms. We found a significant correlation between H-reflex latency and M-latency (r = 0.28), no significant correlation was found between H-reflex latency and thigh length (r = -0.051). Finally based on our findings we introduce a new formula in this paper. We found a significant correlation among of M-response latency and other variables (H-reflex latency and thigh length). Despite this it was eliminated from our formula. The relationship between H-reflex latency and age was significant. Further studies are required to delineate the clinical usage and interpretation of the formula, which we found in this study.

Visual motion direction is represented in population-level neural response as measured by magnetoencephalography.

PubMed

Kaneoke, Y; Urakawa, T; Kakigi, R

2009-05-19

We investigated whether direction information is represented in the population-level neural response evoked by the visual motion stimulus, as measured by magnetoencephalography. Coherent motions with varied speed, varied direction, and different coherence level were presented using random dot kinematography. Peak latency of responses to motion onset was inversely related to speed in all directions, as previously reported, but no significant effect of direction on latency changes was identified. Mutual information entropy (IE) calculated using four-direction response data increased significantly (>2.14) after motion onset in 41.3% of response data and maximum IE was distributed at approximately 20 ms after peak response latency. When response waveforms showing significant differences (by multivariate discriminant analysis) in distribution of the three waveform parameters (peak amplitude, peak latency, and 75% waveform width) with stimulus directions were analyzed, 87 waveform stimulus directions (80.6%) were correctly estimated using these parameters. Correct estimation rate was unaffected by stimulus speed, but was affected by coherence level, even though both speed and coherence affected response amplitude similarly. Our results indicate that speed and direction of stimulus motion are represented in the distinct properties of a response waveform, suggesting that the human brain processes speed and direction separately, at least in part.

Interactions between Herpesvirus Entry Mediator (TNFRSF14) and Latency-Associated Transcript during Herpes Simplex Virus 1 Latency

PubMed Central

Allen, Sariah J.; Rhode-Kurnow, Antje; Mott, Kevin R.; Jiang, Xianzhi; Carpenter, Dale; Rodriguez-Barbosa, J. Ignacio; Jones, Clinton; Wechsler, Steven L.; Ware, Carl F.

2014-01-01

Herpesvirus entry mediator (HVEM) is one of several cell surface proteins herpes simplex virus (HSV) uses for attachment/entry. HVEM regulates cellular immune responses and can also increase cell survival. Interestingly, latency-associated transcript (LAT), the only viral gene consistently expressed during neuronal latency, enhances latency and reactivation by promoting cell survival and by helping the virus evade the host immune response. However, the mechanisms of these LAT activities are not well understood. We show here for the first time that one mechanism by which LAT enhances latency and reactivation appears to be by upregulating HVEM expression. HSV-1 latency/reactivation was significantly reduced in Hvem−/− mice, indicating that HVEM plays a significant role in HSV-1 latency/reactivation. Furthermore, LAT upregulated HVEM expression during latency in vivo and also when expressed in vitro in the absence of other viral factors. This study suggests a mechanism whereby LAT upregulates HVEM expression potentially through binding of two LAT small noncoding RNAs to the HVEM promoter and that the increased HVEM then leads to downregulation of immune responses in the latent microenvironment and increased survival of latently infected cells. Thus, one of the mechanisms by which LAT enhances latency/reactivation appears to be through increasing expression of HVEM. PMID:24307582

Memory-dependent adjustment of vocal response latencies in a territorial songbird.

PubMed

Geberzahn, Nicole; Hultsch, Henrike; Todt, Dietmar

2013-06-01

Vocal interactions in songbirds can be used as a model system to investigate the interplay of intrinsic singing programmes (e.g. influences from vocal memories) and external variables (e.g. social factors). When characterizing vocal interactions between territorial rivals two aspects are important: (1) the timing of songs in relation to the conspecific's singing and (2) the use of a song pattern that matches the rival's song. Responses in both domains can be used to address a territorial rival. This study is the first to investigate the relation of the timing of vocal responses to (1) the vocal memory of a responding subject and (2) the selection of the song pattern that the subject uses as a response. To this end, we conducted interactive playback experiments with adult nightingales (Luscinia megarhynchos) that had been hand-reared and tutored in the laboratory. We analysed the subjects' vocal response latencies towards broadcast playback stimuli that they either had in their own vocal repertoire (songs shared with playback) or that they had not heard before (unknown songs). Likewise, we compared vocal response latencies between responses that matched the stimulus song and those that did not. Our findings showed that the latency of singing in response to the playback was shorter for shared versus unknown song stimuli when subjects overlapped the playback stimuli with their own song. Moreover birds tended to overlap faster when vocally matching the stimulus song rather than when replying with a non-matching song type. We conclude that memory of song patterns influenced response latencies and discuss possible mechanisms. Copyright © 2012 Elsevier Ltd. All rights reserved.

Interference resolution in major depression.

PubMed

Joormann, Jutta; Nee, Derek Evan; Berman, Marc G; Jonides, John; Gotlib, Ian H

2010-03-01

In two experiments, we investigated individual differences in the ability to resolve interference in participants diagnosed with major depressive disorder (MDD). Participants were administered the "Ignore/Suppress" task, a short-term memory task composed of two steps. In Step 1 ("ignore"), participants were instructed to memorize a set of stimuli while ignoring simultaneously presented irrelevant material. In Step 2 ("suppress"), participants were instructed to forget a subset of the previously memorized material. The ability to resolve interference was indexed by response latencies on two recognition tasks in which participants decided whether a probe was a member of the target set. In Step 1, we compared response latencies to probes from the to-be-ignored list with response latencies to nonrecently presented items. In Step 2, we compared response latencies to probes from the to-be-suppressed list with response latencies to nonrecently presented items. The results indicate that, compared with control participants, depressed participants exhibited increased interference in the "suppress" but not in the "ignore" step of the task, when the stimuli were negative words. No group differences were obtained when we presented letters instead of emotional words. These findings indicate that depression is associated with difficulty in removing irrelevant negative material from short-term memory.

High-frequency tone burst-evoked ABR latency-intensity functions.

PubMed

Fausti, S A; Olson, D J; Frey, R H; Henry, J A; Schaffer, H I

1993-01-01

High-frequency tone burst stimuli (8, 10, 12, and 14 kHz) have been developed and demonstrated to provide reliable and valid auditory brainstem responses (ABRs) in normal-hearing subjects. In this study, latency-intensity functions (LIFs) were determined using these stimuli in 14 normal-hearing individuals. Significant shifts in response latency occurred as a function of stimulus intensity for all tone burst frequencies. For each 10 dB shift in intensity, latency shifts for waves I and V were statistically significant except for one isolated instance. LIF slopes were comparable between frequencies, ranging from 0.020 to 0.030 msec/dB. These normal LIFs for high-frequency tone burst-evoked ABRs suggest the degree of response latency change that might be expected from, for example, progressive hearing loss due to ototoxic insult, although these phenomena may not be directly related.

Thinking about false belief: it's not just what children say, but how long it takes them to say it.

PubMed

Atance, Cristina M; Bernstein, Daniel M; Meltzoff, Andrew N

2010-08-01

We examined 240 children's (3.5-, 4.5-, and 5.5-year-olds) latency to respond to questions on a battery of false-belief tasks. Response latencies exhibited a significant cross-over interaction as a function of age and response type (correct vs. incorrect). 3.5-year-olds'incorrect latencies were faster than their correct latencies, whereas the opposite pattern emerged for 4.5- and 5.5-year-olds. Although these results are most consistent with conceptual change theories of false-belief reasoning, no extant theory fully accounts for our data pattern. We argue that response latency data provide new information about underlying cognitive processes in theory of mind reasoning, and can shed light on concept acquisition more broadly. Copyright (c) 2010 Elsevier B.V. All rights reserved.

Correlation between electrical and hemodynamic responses during visual stimulation with graded contrasts

NASA Astrophysics Data System (ADS)

Si, Juanning; Zhang, Xin; Li, Yuejun; Zhang, Yujin; Zuo, Nianming; Jiang, Tianzi

2016-09-01

Brain functional activity involves complex cellular, metabolic, and vascular chain reactions, making it difficult to comprehend. Electroencephalography (EEG) and functional near infrared spectroscopy (fNIRS) have been combined into a multimodal neuroimaging method that captures both electrophysiological and hemodynamic information to explore the spatiotemporal characteristics of brain activity. Because of the significance of visually evoked functional activity in clinical applications, numerous studies have explored the amplitude of the visual evoked potential (VEP) to clarify its relationship with the hemodynamic response. However, relatively few studies have investigated the influence of latency, which has been frequently used to diagnose visual diseases, on the hemodynamic response. Moreover, because the latency and the amplitude of VEPs have different roles in coding visual information, investigating the relationship between latency and the hemodynamic response should be helpful. In this study, checkerboard reversal tasks with graded contrasts were used to evoke visual functional activity. Both EEG and fNIRS were employed to investigate the relationship between neuronal electrophysiological activities and the hemodynamic responses. The VEP amplitudes were linearly correlated with the hemodynamic response, but the VEP latency showed a negative linear correlation with the hemodynamic response.

How to make your own response boxes: A step-by-step guide for the construction of reliable and inexpensive parallel-port response pads from computer mice.

PubMed

Voss, Andreas; Leonhart, Rainer; Stahl, Christoph

2007-11-01

Psychological research is based in large parts on response latencies, which are often registered by keypresses on a standard computer keyboard. Recording response latencies with a standard keyboard is problematic because keypresses are buffered within the keyboard hardware before they are signaled to the computer, adding error variance to the recorded latencies. This can be circumvented by using external response pads connected to the computer's parallel port. In this article, we describe how to build inexpensive, reliable, and easy-to-use response pads with six keys from two standard computer mice that can be connected to the PC's parallel port. We also address the problem of recording data from the parallel port with different software packages under Microsoft's Windows XP.

Overactive bladder and pontine reticular formation.

PubMed

Zorba, Orhan Ünal; Kırbaş, Serkan; Uzun, Hakkı; Cetinkaya, Mehmet; Önem, Kadir; Rifaioğlu, Mehmet Murat

2013-01-01

The etiology of overactive bladder (OAB) remains unclear. Observed neurogenic factors in the literature are limited to suprapontine or spinal pathologies. The blink reflex is a useful tool in the evaluation of brainstem functions. Blink reflex latency times were evaluated in order to reveal pathology in the brainstem. A total of 60 women, 30 patients with idiopathic OAB and 30 healthy controls, were enrolled in the study. Blink reflex latency times were analyzed by electrical stimulation of the supraorbital nerve. Two responses in the orbicularis oculi muscle, early ipsilateral response (R1) and late bilateral response (R2) latency times, were recorded. Mean ages of the patients and controls were 51.9 ± 5.3 and 49.2 ± 6.2 years, respectively. R2 latency times were significantly higher in patients than in controls. However, R1 latency times were similar between the two groups. The results of the study suggest a significant relation between late blink latency times and OAB. An oligosynaptic path via the trigeminal nuclei is responsible for R1; however, R2 response is relayed through the reticular formation. Stimulation of pontine reticular formation inhibits micturition contraction. In some patients, idiopathic OAB may result from reticular formation-originated pathology. Additional studies on other reticular formation-mediated reflexes are needed to reveal possible dysfunction of reticular formation. Copyright © 2013 S. Karger AG, Basel.

Auditory Brainstem Responses from Children Three Months to Three Years of Age: Normal Patterns of Response II.

ERIC Educational Resources Information Center

Gorga, Michael P.; And Others

1989-01-01

Auditory brainstem responses (ABR) were measured in 535 children from 3 months to 3 years of age. Results suggested that changes in wave V latency with age are due to central (neural) factors and that age-appropriate norms should be used in evaluations of ABR latencies in children. (Author/DB)

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

ERIC Educational Resources Information Center

Miezejeski, Charles M.; And Others

1994-01-01

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…

Response Latency as a Function of Hypothesis-Testing Strategies in Concept Identification

ERIC Educational Resources Information Center

Fink, Richard T.

1972-01-01

The ability of M. Levine's subset-sampling assumptions to account for the decrease in response latency following the trial of the last error was investigated by employing a distributed stimulus set composed of four binary dimensions and a procedure which required Ss to make an overt response in order to sample each dimension. (Author)

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

NASA Technical Reports Server (NTRS)

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

1975-01-01

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.

Effects of Differential Reinforcement of Short Latencies on Response Latency, Task Completion, and Accuracy of an Adolescent with Autism

ERIC Educational Resources Information Center

Donohue, Melanie M.; Casey, Laura Baylot; Bicard, David F.; Bicard, Sara E.

2012-01-01

Children with Autism Spectrum Disorder (ASD) are faced with many challenging behaviors that could impede their learning. One commonly reported problem behavior is noncompliance, which is often defined as a delay in response (latency), decrease in rate of responding (fluency), or failure to complete a task. This failure to comply in an appropriate…

Effect of ethanol on the visual-evoked potential in rat: dynamics of ON and OFF responses.

PubMed

Dulinskas, Redas; Buisas, Rokas; Vengeliene, Valentina; Ruksenas, Osvaldas

2017-01-01

The effect of acute ethanol administration on the flash visual-evoked potential (VEP) was investigated in numerous studies. However, it is still unclear which brain structures are responsible for the differences observed in stimulus onset (ON) and offset (OFF) responses and how these responses are modulated by ethanol. The aim of our study was to investigate the pattern of ON and OFF responses in the visual system, measured as amplitude and latency of each VEP component following acute administration of ethanol. VEPs were recorded at the onset and offset of a 500 ms visual stimulus in anesthetized male Wistar rats. The effect of alcohol on VEP latency and amplitude was measured for one hour after injection of 2 g/kg ethanol dose. Three VEP components - N63, P89 and N143 - were analyzed. Our results showed that, except for component N143, ethanol increased the latency of both ON and OFF responses in a similar manner. The latency of N143 during OFF response was not affected by ethanol but its amplitude was reduced. Our study demonstrated that the activation of the visual system during the ON response to a 500 ms visual stimulus is qualitatively different from that during the OFF response. Ethanol interfered with processing of the stimulus duration at the level of the visual cortex and reduced the activation of cortical regions.

The predictability of frequency-altered auditory feedback changes the weighting of feedback and feedforward input for speech motor control.

PubMed

Scheerer, Nichole E; Jones, Jeffery A

2014-12-01

Speech production requires the combined effort of a feedback control system driven by sensory feedback, and a feedforward control system driven by internal models. However, the factors that dictate the relative weighting of these feedback and feedforward control systems are unclear. In this event-related potential (ERP) study, participants produced vocalisations while being exposed to blocks of frequency-altered feedback (FAF) perturbations that were either predictable in magnitude (consistently either 50 or 100 cents) or unpredictable in magnitude (50- and 100-cent perturbations varying randomly within each vocalisation). Vocal and P1-N1-P2 ERP responses revealed decreases in the magnitude and trial-to-trial variability of vocal responses, smaller N1 amplitudes, and shorter vocal, P1 and N1 response latencies following predictable FAF perturbation magnitudes. In addition, vocal response magnitudes correlated with N1 amplitudes, vocal response latencies, and P2 latencies. This pattern of results suggests that after repeated exposure to predictable FAF perturbations, the contribution of the feedforward control system increases. Examination of the presentation order of the FAF perturbations revealed smaller compensatory responses, smaller P1 and P2 amplitudes, and shorter N1 latencies when the block of predictable 100-cent perturbations occurred prior to the block of predictable 50-cent perturbations. These results suggest that exposure to large perturbations modulates responses to subsequent perturbations of equal or smaller size. Similarly, exposure to a 100-cent perturbation prior to a 50-cent perturbation within a vocalisation decreased the magnitude of vocal and N1 responses, but increased P1 and P2 latencies. Thus, exposure to a single perturbation can affect responses to subsequent perturbations. © 2014 Federation of European Neuroscience Societies and John Wiley & Sons Ltd.

Mid-latency auditory evoked potential response revealed as an evidence of neural plasticity in blinnd individuals.

PubMed

Muthusamy, Anbarasi; Gajendran, Rajkumar; Rao B, Vishwanatha

2014-01-01

There is a general impression that visually blind individuals show an exceptionally better perception of other sensory modalities such as hearing, touch and smell sensations. In this study, we intended to compare the mid-latency auditory evoked potential response (MLAEP) or Middle latency Response (MLR) to get an idea of the activity pattern of auditory thalamus and cortex between 30 visually handicapped subjects and 30 normal sighted subjects. The results showed a decrease in many of the MLR wave latencies, but highly significant for the wave Pa (P value <0.002). This fact can be reflected as an evidence of existence of cross-modal neuroplasticity. We also inferred that there are significant gender differences with latencies shorter in males than females (P value <0.02) in the blind subjects group which could be attributed to their rehabilitation training.

Effects of stimulation of phrenic afferents on cervical respiratory interneurones and phrenic motoneurones in cats.

PubMed Central

Iscoe, S; Duffin, J

1996-01-01

1. In ten decerebrate, paralysed and ventilated cats, we tested the hypothesis that cervical (C5) respiratory interneurones mediate inhibition of phrenic motoneurone activity resulting from single shocks to the phrenic nerve. 2. Stimulus intensities sufficient to activate all afferents elicited (latency, 4.0 +/- 0.9 ms, mean +/- S.D.) a graded suppression of ipsilateral, but not contralateral (five of seven cats) phrenic nerve activity lasting, in six of seven cats, more than 70 ms and interrupted by a brief (approximately 6-18 ms duration) excitation at latencies between 7 and 30 ms. 3. In twenty-five ipsilateral motoneurones, peristimulus time average of the membrane potentials (-61 +/- 10 mV) showed no effect in eleven; of the fourteen that responded, ten had initial EPSPs (latency, 17.6 +/- 3.0 ms) and four initial IPSPs (latencies, 2.25-4.3 ms). Only one motoneurone had both. No responses with latencies > 60 ms were observed. 4. Peristimulus time averages of extracellular activity of thirty ipsilateral interneurones, twenty-five firing in inspiration (I) and five in expiration (E), showed diverse responses. The initial response of I interneurones was an excitation in eleven, a suppression of activity in nine, and no response in five. Latencies of excitations ranged from 2 to 36.5 ms (median, 14 ms) with durations ranging from 2 to 7 ms (mean, 4.4 +/- 1.6 ms). Latencies of suppression of activity ranged from 2 to 29 ms (median, 10 ms). Two E interneurones were excited (latencies, 11 and 15 ms; durations, 3.5 and 2 ms), two inhibited (latencies, 2 and 12 ms; durations, > 40 and 17 ms, respectively), and one did not respond. 5. In nine interneurones (seven I, two E), peristimulus time averages of the membrane potentials (mean, -62 +/- 14 mV) revealed no effect on three (all I). Of the six that responded, four (three I) had initial IPSPs, two (one I, one E) initial EPSPs. EPSPs had latencies of 11.5 (I interneurone) and 22 ms (E interneurone); the latencies of the IPSPs were 2.75, 3.20, and 2.3 ms for the I interneurones and 15.9 ms for the E interneurone). No responses with latencies > 30 ms were observed. 6. The diverse responses of cervical respiratory interneurones indicates that they do not mediate the prolonged suppression of ipsilateral phrenic activity elicited by stimulation of phrenic afferents. The suppression may result from activation of normally quiescent inhibitory interneurones or from presynaptic inhibition. PMID:9003565

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)

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

1984-01-01

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.

Control of complex motor gestures: orofacial muscle responses to load perturbations of lip during speech.

PubMed

Abbs, J H; Gracco, V L

1984-04-01

The contribution of ascending afferents to the control of speech movement was evaluated by applying unanticipated loads to the lower lip during the generation of combined upper lip-lower lip speech gestures. To eliminate potential contamination due to anticipation or adaptation, loads were applied randomly on only 10-15% of the trials. Physical characteristics of the perturbations were within the normal range of forces and movements involved in natural lip actions for speech. Compensatory responses in multiple facial muscles and lip movements were observed the first time a load was introduced, and achievement of the multimovement speech goals was never disrupted by these perturbations. Muscle responses were seen in the lower lip muscles, implicating corrective, feedback processes. Additionally, compensatory responses to these lower lip loads were also observed in the independently controlled muscles of the upper lip, reflecting the parallel operation of open-loop, sensorimotor mechanisms. Compensatory responses from both the upper and lower lip muscles were observed with small (1 mm) as well as large (15 mm) perturbations. The latencies of these compensatory responses were not discernible by conventional ensemble averaging. Moreover, responses at latencies of lower brain stem-mediated reflexes (i.e., 10-18 ms) were not apparent with inspection of individual records. Response latencies were determined on individual loaded trials through the use of a computer algorithm that took into account the variability of electromyograms (EMG) among the control trials. These latency measures confirmed the absence of brain stem-mediated responses and yielded response latencies that ranged from 22 to 75 ms. Response latencies appeared to be influenced by the time relation between load onset and the initiation of muscle activation. Examination of muscle activity changes for individual loaded trials revealed complementary variations in the magnitude of responses among multiple muscles contributing to a movement compensation. These observations may have implications for limb movement control if multimovement speech gestures are considered analogous to a limb action requiring coordinated movements around multiple joints. In this context, these speech motor control data might be interpreted to suggest that for complex movements, both corrective feedback and open-loop predictive processes are operating, with the latter involved in the control of coordination among multiple movement subcomponents.

Using Arduino microcontroller boards to measure response latencies.

PubMed

Schubert, Thomas W; D'Ausilio, Alessandro; Canto, Rosario

2013-12-01

Latencies of buttonpresses are a staple of cognitive science paradigms. Often keyboards are employed to collect buttonpresses, but their imprecision and variability decreases test power and increases the risk of false positives. Response boxes and data acquisition cards are precise, but expensive and inflexible, alternatives. We propose using open-source Arduino microcontroller boards as an inexpensive and flexible alternative. These boards connect to standard experimental software using a USB connection and a virtual serial port, or by emulating a keyboard. In our solution, an Arduino measures response latencies after being signaled the start of a trial, and communicates the latency and response back to the PC over a USB connection. We demonstrated the reliability, robustness, and precision of this communication in six studies. Test measures confirmed that the error added to the measurement had an SD of less than 1 ms. Alternatively, emulation of a keyboard results in similarly precise measurement. The Arduino performs as well as a serial response box, and better than a keyboard. In addition, our setup allows for the flexible integration of other sensors, and even actuators, to extend the cognitive science toolbox.

Electrical stimulation to the trigeminal proprioceptive fibres that innervate the mechanoreceptors in Müller's muscle induces involuntary reflex contraction of the frontalis muscles.

PubMed

Matsuo, Kiyoshi; Osada, Yoshiro; Ban, Ryokuya

2013-02-01

The levator and frontalis muscles lack interior muscle spindles, despite consisting of slow-twitch fibres that involuntarily sustain eyelid-opening and eyebrow-raising against gravity. To compensate for this anatomical defect, this study hypothetically proposes that initial voluntary contraction of the levator fast-twitch muscle fibres stretches the mechanoreceptors in Müller's muscle and evokes proprioception, which continuously induces reflex contraction of slow-twitch fibres of the levator and frontalis muscles. This study sought to determine whether unilateral transcutaneous electrical stimulation to the trigeminal proprioceptive fibres that innervate the mechanoreceptors in Müller's muscle could induce electromyographic responses in the frontalis muscles, with monitoring responses in the orbicularis oculi muscles. The study population included 27 normal subjects and 23 subjects with aponeurotic blepharoptosis, who displayed persistently raised eyebrows on primary gaze and light eyelid closure. The stimulation induced a short-latency response in the ipsilateral frontalis muscle of all subjects and long-latency responses in the bilateral frontalis muscles of normal subjects. However, it did not induce long-latency responses in the bilateral frontalis muscles of subjects with aponeurotic blepharoptosis. The orbicularis oculi muscles showed R1 and/or R2 responses. The stimulation might reach not only the proprioceptive fibres, but also other sensory fibres related to the blink or corneal reflex. The experimental system can provoke a monosynaptic short-latency response in the ipsilateral frontalis muscle, probably through the mesencephalic trigeminal proprioceptive neuron and the frontalis motor neuron, and polysynaptic long-latency responses in the bilateral frontalis muscles through an unknown pathway. The latter neural circuit appeared to be engaged by the circumstances of aponeurotic blepharoptosis.

Pursuit Latency for Chromatic Targets

NASA Technical Reports Server (NTRS)

Mulligan, Jeffrey B.; Ellis, Stephen R. (Technical Monitor)

1998-01-01

The temporal dynamics of eye movement response to a change in direction of stimulus motion has been used to compare the processing speeds of different types of stimuli (Mulligan, ARVO '97). In this study, the pursuit response to colored targets was measured to test the hypothesis that the slow response of the chromatic system (as measured using traditional temporal sensitivity measures such as contrast sensitivity) results in increased eye movement latencies. Subjects viewed a small (0.4 deg) Gaussian spot which moved downward at a speed of 6.6 deg/sec. At a variable time during the trajectory, the dot's direction of motion changed by 30 degrees, either to the right or left. Subjects were instructed to pursue the spot. Eye movements were measured using a video ophthalmoscope with an angular resolution of approximately 1 arc min and a temporal sampling rate of 60 Hz. Stimuli were modulated in chrominance for a variety of hue directions, combined with a range of small luminance increments and decrements, to insure that some of the stimuli fell in the subjects' equiluminance planes. The smooth portions of the resulting eye movement traces were fit by convolving the stimulus velocity with an exponential having variable onset latency, time constant and amplitude. Smooth eye movements with few saccades were observed for all stimuli. Pursuit responses to stimuli having a significant luminance component are well-fit by exponentials having latencies and time constants on the order of 100 msec. Increases in pursuit response latency on the order of 100-200 msec are observed in response to certain stimuli, which occur in pairs of complementary hues, corresponding to the intersection of the stimulus section with the subjects' equiluminant plane. Smooth eye movements can be made in response to purely chromatic stimuli, but are slower than responses to stimuli with a luminance component.

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

NASA Technical Reports Server (NTRS)

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

1997-01-01

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.

Effects of aging and involuntary capture of attention on event-related potentials associated with the processing of and the response to a target stimulus

PubMed Central

Cid-Fernández, Susana; Lindín, Mónica; Díaz, Fernando

2014-01-01

The main aim of the present study was to assess whether aging modulates the effects of involuntary capture of attention by novel stimuli on performance, and on event-related potentials (ERPs) associated with target processing (N2b and P3b) and subsequent response processes (stimulus-locked Lateralized Readiness Potential -sLRP- and response-locked Lateralized Readiness Potential -rLRP-). An auditory-visual distraction-attention task was performed by 77 healthy participants, divided into three age groups (Young: 21–29, Middle-aged: 51–64, Old: 65–84 years old). Participants were asked to attend to visual stimuli and to ignore auditory stimuli. Aging was associated with slowed reaction times, target stimulus processing in working memory (WM, longer N2b and P3b latencies) and selection and preparation of the motor response (longer sLRP and earlier rLRP onset latencies). In the novel relative to the standard condition we observed, in the three age groups: (1) a distraction effect, reflected in a slowing of reaction times, of stimuli categorization in WM (longer P3b latency), and of motor response selection (longer sLRP onset latency); (2) a facilitation effect on response preparation (later rLRP onset latency), and (3) an increase in arousal (larger amplitudes of all ERPs evaluated, except for N2b amplitude in the Old group). A distraction effect on the stimulus evaluation processes (longer N2b latency) were also observed, but only in middle-aged and old participants, indicating that the attentional capture slows the stimulus evaluation in WM from early ages (from 50 years onwards, without differences between middle-age and older adults), but not in young adults. PMID:25294999

Timing in Trace Conditioning of the Nictitating Membrane Response of the Rabbit ("Oryctolagus Cuniculus"): Scalar, Nonscalar, and Adaptive Features

ERIC Educational Resources Information Center

Kehoe, E. James; Ludvig, Elliot A.; Sutton, Richard S.

2010-01-01

Using interstimulus intervals (ISIs) of 125, 250, and 500 msec in trace conditioning of the rabbit nictitating membrane response, the offset times and durations of conditioned responses (CRs) were collected along with onset and peak latencies. All measures were proportional to the ISI, but only onset and peak latencies conformed to the criterion…

Effects of analog and digital filtering on auditory middle latency responses in adults and young children.

PubMed

Suzuki, T; Hirabayashi, M; Kobayashi, K

1984-01-01

Effects of analog high pass (HP) filtering were compared with those of zero phase-shift digital filtering on the auditory middle latency responses (MLR) from nine adults and 16 young children with normal hearing. Analog HP filtering exerted several prominent effects on the MLR waveforms in both adults and young children, such as suppression of Po (ABR), enhancement of Nb, enhancement or emergence of Pb, and latency decrements for Pa and the later components. Analog HP filtering at 20 Hz produced more pronounced waveform distortions in the responses from young children than from adults. Much greater latency decrements for Pa and Nb were observed for young children than for adults in the analog HP-filtered responses at 20 Hz. A large positive peak (Pb) emerged at about 65 ms after the stimulus onset. From these results, the use of digital HP filtering at 20 Hz is strongly recommended for obtaining unbiased and stable MLR in young children.

Auditory Middle Latency Response and Phonological Awareness in Students with Learning Disabilities

PubMed Central

Romero, Ana Carla Leite; Funayama, Carolina Araújo Rodrigues; Capellini, Simone Aparecida; Frizzo, Ana Claudia Figueiredo

2015-01-01

Introduction Behavioral tests of auditory processing have been applied in schools and highlight the association between phonological awareness abilities and auditory processing, confirming that low performance on phonological awareness tests may be due to low performance on auditory processing tests. Objective To characterize the auditory middle latency response and the phonological awareness tests and to investigate correlations between responses in a group of children with learning disorders. Methods The study included 25 students with learning disabilities. Phonological awareness and auditory middle latency response were tested with electrodes placed on the left and right hemispheres. The correlation between the measurements was performed using the Spearman rank correlation coefficient. Results There is some correlation between the tests, especially between the Pa component and syllabic awareness, where moderate negative correlation is observed. Conclusion In this study, when phonological awareness subtests were performed, specifically phonemic awareness, the students showed a low score for the age group, although for the objective examination, prolonged Pa latency in the contralateral via was observed. Negative weak to moderate correlation for Pa wave latency was observed, as was positive weak correlation for Na-Pa amplitude. PMID:26491479

Effects of Predictability of Load Magnitude on the Response of the Flexor Digitorum Superficialis to a Sudden Fingers Extension

PubMed Central

Aimola, Ettore; Valle, Maria Stella; Casabona, Antonino

2014-01-01

Muscle reflexes, evoked by opposing a sudden joint displacement, may be modulated by several factors associated with the features of the mechanical perturbation. We investigated the variations of muscle reflex response in relation to the predictability of load magnitude during a reactive grasping task. Subjects were instructed to flex the fingers 2–5 very quickly after a stretching was exerted by a handle pulled by loads of 750 or 1250 g. Two blocks of trials, one for each load (predictable condition), and one block of trials with a randomized distribution of the loads (unpredictable condition) were performed. Kinematic data were collected by an electrogoniometer attached to the middle phalanx of the digit III while the electromyography of the Flexor Digitorum Superficialis muscle was recorded by surface electrodes. For each trial we measured the kinematics of the finger angular rotation, the latency of muscle response and the level of muscle activation recorded below 50 ms (short-latency reflex), between 50 and 100 ms (long-latency reflex) and between 100 and 140 ms (initial portion of voluntary response) from the movement onset. We found that the latency of the muscle response lengthened from predictable (35.5±1.3 ms for 750 g and 35.5±2.5 ms for 1250 g) to unpredictable condition (43.6±1.3 ms for 750 g and 40.9±2.1 ms for 1250 g) and the level of muscle activation increased with load magnitude. The parallel increasing of muscle activation and load magnitude occurred within the window of the long-latency reflex during the predictable condition, and later, at the earliest portion of the voluntary response, in the unpredictable condition. Therefore, these results indicate that when the amount of an upcoming perturbation is known in advance, the muscle response improves, shortening the latency and modulating the muscle activity in relation to the mechanical demand. PMID:25271638

Dynamic Alignment Models for Neural Coding

PubMed Central

Kollmorgen, Sepp; Hahnloser, Richard H. R.

2014-01-01

Recently, there have been remarkable advances in modeling the relationships between the sensory environment, neuronal responses, and behavior. However, most models cannot encompass variable stimulus-response relationships such as varying response latencies and state or context dependence of the neural code. Here, we consider response modeling as a dynamic alignment problem and model stimulus and response jointly by a mixed pair hidden Markov model (MPH). In MPHs, multiple stimulus-response relationships (e.g., receptive fields) are represented by different states or groups of states in a Markov chain. Each stimulus-response relationship features temporal flexibility, allowing modeling of variable response latencies, including noisy ones. We derive algorithms for learning of MPH parameters and for inference of spike response probabilities. We show that some linear-nonlinear Poisson cascade (LNP) models are a special case of MPHs. We demonstrate the efficiency and usefulness of MPHs in simulations of both jittered and switching spike responses to white noise and natural stimuli. Furthermore, we apply MPHs to extracellular single and multi-unit data recorded in cortical brain areas of singing birds to showcase a novel method for estimating response lag distributions. MPHs allow simultaneous estimation of receptive fields, latency statistics, and hidden state dynamics and so can help to uncover complex stimulus response relationships that are subject to variable timing and involve diverse neural codes. PMID:24625448

Ventral pallidal encoding of reward-seeking behavior depends on the underlying associative structure

PubMed Central

Stout, Nakura; Acs, Deanna

2018-01-01

Despite its being historically conceptualized as a motor expression site, emerging evidence suggests the ventral pallidum (VP) plays a more active role in integrating information to generate motivation. Here, we investigated whether rat VP cue responses would encode and contribute similarly to the vigor of reward-seeking behaviors trained under Pavlovian versus instrumental contingencies, when these behavioral responses consist of superficially similar locomotor response patterns but may reflect distinct underlying decision-making processes. We find that cue-elicited activity in many VP neurons predicts the latency of instrumental reward seeking, but not of Pavlovian response latency. Further, disruption of VP signaling increases the latency of instrumental but not Pavlovian reward seeking. This suggests that VP encoding of and contributions to response vigor are specific to the ability of incentive cues to invigorate reward-seeking behaviors upon which reward delivery is contingent. PMID:29565248

Stimulus selectivity and response latency in putative inhibitory and excitatory neurons of the primate inferior temporal cortex

PubMed Central

Mruczek, Ryan E. B.

2012-01-01

The cerebral cortex is composed of many distinct classes of neurons. Numerous studies have demonstrated corresponding differences in neuronal properties across cell types, but these comparisons have largely been limited to conditions outside of awake, behaving animals. Thus the functional role of the various cell types is not well understood. Here, we investigate differences in the functional properties of two widespread and broad classes of cells in inferior temporal cortex of macaque monkeys: inhibitory interneurons and excitatory projection cells. Cells were classified as putative inhibitory or putative excitatory neurons on the basis of their extracellular waveform characteristics (e.g., spike duration). Consistent with previous intracellular recordings in cortical slices, putative inhibitory neurons had higher spontaneous firing rates and higher stimulus-evoked firing rates than putative excitatory neurons. Additionally, putative excitatory neurons were more susceptible to spike waveform adaptation following very short interspike intervals. Finally, we compared two functional properties of each neuron's stimulus-evoked response: stimulus selectivity and response latency. First, putative excitatory neurons showed stronger stimulus selectivity compared with putative inhibitory neurons. Second, putative inhibitory neurons had shorter response latencies compared with putative excitatory neurons. Selectivity differences were maintained and latency differences were enhanced during a visual search task emulating more natural viewing conditions. Our results suggest that short-latency inhibitory responses are likely to sculpt visual processing in excitatory neurons, yielding a sparser visual representation. PMID:22933717

Electrical stimulation reveals relatively ineffective sural nerve projections to dorsal horn neurons in the cat.

PubMed

Pubols, L M; Foglesong, M E; Vahle-Hinz, C

1986-04-16

Electrical stimulation of the sural nerve (SN) revealed input from sural nerve afferents to L6 and L7 dorsal horn neurons that were not apparent using natural mechanical stimuli, especially in cells with variable latency responses to SN stimulation. Nearly all (31/32) cells that had reliable, fixed latency responses to SN stimulation also had an excitatory receptive field (RF) in the region of skin innervated by the sural nerve (SN region). About one-third (20/57) of the cells with variable latency responses to SN stimulation, however, had an RF outside the SN region. Most (130/146) cells with no response to SN stimulation had RFs outside the SN region. There were no obvious differences between variable latency cells with RFs in the SN region vs those with RFs outside it in latency of response to SN stimulation, recording depth, RF sizes or modality properties. In a subsample of 31 postsynaptic dorsal column neurons all cells responding to SN stimulation also had an RF in the SN region. Strengthening of relatively ineffective projections from the sural nerve by lesions might be expected to lead to an increase in the proportion of cells responding with impulses to natural stimulation of the skin innervated by the sural nerve, and, hence, to an increase in average RF size.

Amplitude, Latency, and Peak Velocity in Accommodation and Disaccommodation Dynamics

PubMed Central

Papadatou, Eleni; Ferrer-Blasco, Teresa; Montés-Micó, Robert

2017-01-01

The aim of this work was to ascertain whether there are differences in amplitude, latency, and peak velocity of accommodation and disaccommodation responses when different analysis strategies are used to compute them, such as fitting different functions to the responses or for smoothing them prior to computing the parameters. Accommodation and disaccommodation responses from four subjects to pulse changes in demand were recorded by means of aberrometry. Three different strategies were followed to analyze such responses: fitting an exponential function to the experimental data; fitting a Boltzmann sigmoid function to the data; and smoothing the data. Amplitude, latency, and peak velocity of the responses were extracted. Significant differences were found between the peak velocity in accommodation computed by fitting an exponential function and smoothing the experimental data (mean difference 2.36 D/s). Regarding disaccommodation, significant differences were found between latency and peak velocity, calculated with the two same strategies (mean difference of 0.15 s and −3.56 D/s, resp.). The strategy used to analyze accommodation and disaccommodation responses seems to affect the parameters that describe accommodation and disaccommodation dynamics. These results highlight the importance of choosing the most adequate analysis strategy in each individual to obtain the parameters that characterize accommodation and disaccommodation dynamics. PMID:29226128

Single-Trial Analysis of V1 Responses Suggests Two Transmission States

NASA Technical Reports Server (NTRS)

Shah, A. S.; Knuth, K. H.; Truccolo, W. A.; Mehta, A. D.; McGinnis, T.; OConnell, N.; Ding, M.; Bressler, S. L.; Schroeder, C. E.

2002-01-01

Sensory processing in the visual, auditory, and somatosensory systems is often studied by recording electrical activity in response to a stimulus of interest. Typically, multiple trial responses to the stimulus are averaged to isolate the stereotypic response from noise. However, averaging ignores dynamic variability in the neuronal response, which is potentially critical to understanding stimulus-processing schemes. Thus, we developed the multiple component, Event-Related Potential (mcERP) model. This model asserts that multiple components, defined as stereotypic waveforms, comprise the stimulus-evoked response and that these components may vary in amplitude and latency from trial to trial. Application of this model to data recorded simultaneously from all six laminae of V1 in an awake, behaving monkey performing a visual discrimination yielded three components. The first component localized to granular V1, the second was located in supragranular V1, and the final component displayed a multi-laminar distribution. These modeling results, which take into account single-trial response dynamics, illustrated that the initial activation of VI occurs in the granular layer followed by activation in the supragranular layers. This finding is expected because the average response in those layers demonstrates the same progression and because anatomical evidence suggests that the feedforward input in V1 enters the granular layer and progresses to supragranular layers. In addition to these findings, the granular component of the model displayed several interesting trial-to-trial characteristics including (1) a bimodal latency distribution, (2) a latency-related variation in response amplitude, (3) a latency correlation with the supragranular component, and (4) an amplitude and latency association with the multi-laminar component. Direct analyses of the single-trial data were consistent with these model predictions. These findings suggest that V1 has at least 2 transmission states, which may be modulated by various effects such as attention, dynamics in local EEG rhythm, or variation in sensory inputs.

A 2.5-Kilobase Deletion Containing a Cluster of Nine MicroRNAs in the Latency-Associated-Transcript Locus of the Pseudorabies Virus Affects the Host Response of Porcine Trigeminal Ganglia during Established Latency

PubMed Central

Mahjoub, Nada; Dhorne-Pollet, Sophie; Fuchs, Walter; Endale Ahanda, Marie-Laure; Lange, Elke; Klupp, Barbara; Arya, Anoop; Loveland, Jane E.; Lefevre, François; Mettenleiter, Thomas C.

2014-01-01

ABSTRACT The alphaherpesvirus pseudorabies virus (PrV) establishes latency primarily in neurons of trigeminal ganglia when only the transcription of the latency-associated transcript (LAT) locus is detected. Eleven microRNAs (miRNAs) cluster within the LAT, suggesting a role in establishment and/or maintenance of latency. We generated a mutant (M) PrV deleted of nine miRNA genes which displayed properties that were almost identical to those of the parental PrV wild type (WT) during propagation in vitro. Fifteen pigs were experimentally infected with either WT or M virus or were mock infected. Similar levels of virus excretion and host antibody response were observed in all infected animals. At 62 days postinfection, trigeminal ganglia were excised and profiled by deep sequencing and quantitative RT-PCR. Latency was established in all infected animals without evidence of viral reactivation, demonstrating that miRNAs are not essential for this process. Lower levels of the large latency transcript (LLT) were found in ganglia infected by M PrV than in those infected by WT PrV. All PrV miRNAs were expressed, with highest expression observed for prv-miR-LLT1, prv-miR-LLT2 (in WT ganglia), and prv-miR-LLT10 (in both WT and M ganglia). No evidence of differentially expressed porcine miRNAs was found. Fifty-four porcine genes were differentially expressed between WT, M, and control ganglia. Both viruses triggered a strong host immune response, but in M ganglia gene upregulation was prevalent. Pathway analyses indicated that several biofunctions, including those related to cell-mediated immune response and the migration of dendritic cells, were impaired in M ganglia. These findings are consistent with a function of the LAT locus in the modulation of host response for maintaining a latent state. IMPORTANCE This study provides a thorough reference on the establishment of latency by PrV in its natural host, the pig. Our results corroborate the evidence obtained from the study of several LAT mutants of other alphaherpesviruses encoding miRNAs from their LAT regions. Neither PrV miRNA expression nor high LLT expression levels are essential to achieve latency in trigeminal ganglia. Once latency is established by PrV, the only remarkable differences are found in the pattern of host response. This indicates that, as in herpes simplex virus, LAT functions as an immune evasion locus. PMID:25320324

Encoding of sound envelope transients in the auditory cortex of juvenile rats and adult rats.

PubMed

Lu, Qi; Jiang, Cuiping; Zhang, Jiping

2016-02-01

Accurate neural processing of time-varying sound amplitude and spectral information is vital for species-specific communication. During postnatal development, cortical processing of sound frequency undergoes progressive refinement; however, it is not clear whether cortical processing of sound envelope transients also undergoes age-related changes. We determined the dependence of neural response strength and first-spike latency on sound rise-fall time across sound levels in the primary auditory cortex (A1) of juvenile (P20-P30) rats and adult (8-10 weeks) rats. A1 neurons were categorized as "all-pass", "short-pass", or "mixed" ("all-pass" at high sound levels to "short-pass" at lower sound levels) based on the normalized response strength vs. rise-fall time functions across sound levels. The proportions of A1 neurons within each of the three categories in juvenile rats were similar to that in adult rats. In general, with increasing rise-fall time, the average response strength decreased and the average first-spike latency increased in A1 neurons of both groups. At a given sound level and rise-fall time, the average normalized neural response strength did not differ significantly between the two age groups. However, the A1 neurons in juvenile rats showed greater absolute response strength, longer first-spike latency compared to those in adult rats. In addition, at a constant sound level, the average first-spike latency of juvenile A1 neurons was more sensitive to changes in rise-fall time. Our results demonstrate the dependence of the responses of rat A1 neurons on sound rise-fall time, and suggest that the response latency exhibit some age-related changes in cortical representation of sound envelope rise time. Copyright © 2015 Elsevier Ltd. All rights reserved.

Cumulative latency advance underlies fast visual processing in desynchronized brain state

PubMed Central

Wang, Xu-dong; Chen, Cheng; Zhang, Dinghong; Yao, Haishan

2014-01-01

Fast sensory processing is vital for the animal to efficiently respond to the changing environment. This is usually achieved when the animal is vigilant, as reflected by cortical desynchronization. However, the neural substrate for such fast processing remains unclear. Here, we report that neurons in rat primary visual cortex (V1) exhibited shorter response latency in the desynchronized state than in the synchronized state. In vivo whole-cell recording from the same V1 neurons undergoing the two states showed that both the resting and visually evoked conductances were higher in the desynchronized state. Such conductance increases of single V1 neurons shorten the response latency by elevating the membrane potential closer to the firing threshold and reducing the membrane time constant, but the effects only account for a small fraction of the observed latency advance. Simultaneous recordings in lateral geniculate nucleus (LGN) and V1 revealed that LGN neurons also exhibited latency advance, with a degree smaller than that of V1 neurons. Furthermore, latency advance in V1 increased across successive cortical layers. Thus, latency advance accumulates along various stages of the visual pathway, likely due to a global increase of membrane conductance in the desynchronized state. This cumulative effect may lead to a dramatic shortening of response latency for neurons in higher visual cortex and play a critical role in fast processing for vigilant animals. PMID:24347634

Cumulative latency advance underlies fast visual processing in desynchronized brain state.

PubMed

Wang, Xu-dong; Chen, Cheng; Zhang, Dinghong; Yao, Haishan

2014-01-07

Fast sensory processing is vital for the animal to efficiently respond to the changing environment. This is usually achieved when the animal is vigilant, as reflected by cortical desynchronization. However, the neural substrate for such fast processing remains unclear. Here, we report that neurons in rat primary visual cortex (V1) exhibited shorter response latency in the desynchronized state than in the synchronized state. In vivo whole-cell recording from the same V1 neurons undergoing the two states showed that both the resting and visually evoked conductances were higher in the desynchronized state. Such conductance increases of single V1 neurons shorten the response latency by elevating the membrane potential closer to the firing threshold and reducing the membrane time constant, but the effects only account for a small fraction of the observed latency advance. Simultaneous recordings in lateral geniculate nucleus (LGN) and V1 revealed that LGN neurons also exhibited latency advance, with a degree smaller than that of V1 neurons. Furthermore, latency advance in V1 increased across successive cortical layers. Thus, latency advance accumulates along various stages of the visual pathway, likely due to a global increase of membrane conductance in the desynchronized state. This cumulative effect may lead to a dramatic shortening of response latency for neurons in higher visual cortex and play a critical role in fast processing for vigilant animals.

Method for triggering an action

DOEpatents

Hall, David R.; Bartholomew, David B.; Johnson, Monte L.; Moon, Justin; Koehler, Roger O.

2006-10-17

A method for triggering an action of at least one downhole device on a downhole network integrated into a downhole tool string synchronized to an event comprises determining latency, sending a latency adjusted signal, and performing the action. The latency is determined between a control device and the at least one downhole device. The latency adjusted signal for triggering an action is sent to the downhole device. The action is performed downhole synchronized to the event. A preferred method for determining latency comprises the steps: a control device sends a first signal to the downhole device; after receiving the signal, the downhole device sends a response signal to the control device; and the control device analyzes the time from sending the signal to receiving the response signal.

Effects of Antipsychotic Drugs Haloperidol and Clozapine on Visual Responses of Retinal Ganglion Cells in a Rat Model of Retinitis Pigmentosa.

PubMed

Jensen, Ralph J

2016-12-01

In the P23H rat model of retinitis pigmentosa, the dopamine D2 receptor antagonists sulpiride and eticlopride appear to improve visual responses of retinal ganglion cells (RGCs) by increasing light sensitivity of RGCs and transforming abnormal, long-latency ON-center RGCs into OFF-center cells. Antipsychotic drugs are believed to mediate their therapeutic benefits by blocking D2 receptors. This investigation was conducted to test whether haloperidol (a typical antipsychotic drug) and clozapine (an atypical antipsychotic drug) could similarly alter the light responses of RGCs in the P23H rat retina. Extracellular recordings were made from RGCs in isolated P23H rat retinas. Responses of RGCs to flashes of light were evaluated before and during bath application of a drug. Both haloperidol and clozapine increased light sensitivity of RGCs on average by ∼0.3 log unit. For those ON-center RGCs that exhibit an abnormally long-latency response to the onset of a small spot of light, both haloperidol and clozapine brought out a short-latency OFF response and markedly reduced the long-latency ON response. The selective serotonin 5-HT2A antagonist MDL 100907 had similar effects on RGCs. The effects of haloperidol on light responses of RGCs can be explained by its D2 receptor antagonism. The effects of clozapine on light responses of RGCs on the other hand may largely be due to its 5-HT2A receptor antagonism. Overall, the results suggest that antipsychotic drugs may be useful in improving vision in patients with retinitis pigmentosa.

Short latency vestibular evoked potentials in the chicken embryo

NASA Technical Reports Server (NTRS)

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

1996-01-01

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.

Primary visual response (M100) delays in adolescents with FASD as measured with MEG.

PubMed

Coffman, Brian A; Kodituwakku, Piyadasa; Kodituwakku, Elizabeth L; Romero, Lucinda; Sharadamma, Nirupama Muniswamy; Stone, David; Stephen, Julia M

2013-11-01

Fetal alcohol spectrum disorders (FASD) are debilitating, with effects of prenatal alcohol exposure persisting into adolescence and adulthood. Complete characterization of FASD is crucial for the development of diagnostic tools and intervention techniques to decrease the high cost to individual families and society of this disorder. In this experiment, we investigated visual system deficits in adolescents (12-21 years) diagnosed with an FASD by measuring the latency of patients' primary visual M100 responses using MEG. We hypothesized that patients with FASD would demonstrate delayed primary visual responses compared to controls. M100 latencies were assessed both for FASD patients and age-matched healthy controls for stimuli presented at the fovea (central stimulus) and at the periphery (peripheral stimuli; left or right of the central stimulus) in a saccade task requiring participants to direct their attention and gaze to these stimuli. Source modeling was performed on visual responses to the central and peripheral stimuli and the latency of the first prominent peak (M100) in the occipital source timecourse was identified. The peak latency of the M100 responses were delayed in FASD patients for both stimulus types (central and peripheral), but the difference in latency of primary visual responses to central vs. peripheral stimuli was significant only in FASD patients, indicating that, while FASD patients' visual systems are impaired in general, this impairment is more pronounced in the periphery. These results suggest that basic sensory deficits in this population may contribute to sensorimotor integration deficits described previously in this disorder. Copyright © 2012 Wiley Periodicals, Inc.

Are automatic postural responses in patients with Parkinson's disease abnormal due to their stooped posture?

PubMed

Bloem, B R; Beckley, D J; van Dijk, J G

1999-02-01

Abnormal automatic postural responses are thought to contribute to balance impairment in Parkinson's disease. However, because postural responses are modifiable by stance, we have speculated that some postural abnormalities in patients with Parkinson's disease are secondary to their stooped stance. We have studied this assumption by assessing automatic postural responses in 30 healthy subjects who were instructed either to stand upright or to assume a typical parkinsonian posture. During both conditions, subjects received 20 serial 4 degrees 'toe-up' rotational perturbations from a supporting forceplate. We recorded short-latency (SL) and medium-latency (ML) responses from stretched gastrocnemius muscles and long-latency (LL) responses from shortened tibialis anterior muscles. We also assessed changes in the center of foot pressure (CFP) and the center of gravity (COG). The results were qualitatively compared to a previously described group of patients with Parkinson's disease who, under these circumstances, typically have large ML responses, small LL responses and insufficient voluntary postural corrections, accompanied by a slow rate of backward CFP displacement and an increased posterior COG displacement. The stooped posture resulted in unloading of medial gastrocnemius muscles and loading of tibialis anterior muscles. Onset latencies of stretch responses in gastrocnemius muscles were delayed in stooped subjects, but the onset of LL responses was markedly reduced. Amplitudes of both ML and LL responses were reduced in stooped subjects. Prestimulus COG and, to a lesser extent, CFP were shifted forwards in stooped subjects. Posterior COG displacement and the rate of backward CFP displacement were diminished in stooped subjects. Voluntary postural corrections were unchanged while standing stooped. These results indicate that some postural abnormalities of patients with Parkinson's disease (most notably the reduced LL responses) can be reproduced in healthy subjects mimicking a stooped parkinsonian posture. Other postural abnormalities (most notably the increased ML responses and insufficient voluntary responses) did not appear in stooped controls and may contribute to balance impairment in Parkinson's disease.

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, N P M; Paillard, A C; Kluk, K; Whittle, E; Colebatch, J G

2014-06-01

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. Copyright © 2014 The Authors. Published by Elsevier B.V. All rights reserved.

Tap Arduino: An Arduino microcontroller for low-latency auditory feedback in sensorimotor synchronization experiments.

PubMed

Schultz, Benjamin G; van Vugt, Floris T

2016-12-01

Timing abilities are often measured by having participants tap their finger along with a metronome and presenting tap-triggered auditory feedback. These experiments predominantly use electronic percussion pads combined with software (e.g., FTAP or Max/MSP) that records responses and delivers auditory feedback. However, these setups involve unknown latencies between tap onset and auditory feedback and can sometimes miss responses or record multiple, superfluous responses for a single tap. These issues may distort measurements of tapping performance or affect the performance of the individual. We present an alternative setup using an Arduino microcontroller that addresses these issues and delivers low-latency auditory feedback. We validated our setup by having participants (N = 6) tap on a force-sensitive resistor pad connected to the Arduino and on an electronic percussion pad with various levels of force and tempi. The Arduino delivered auditory feedback through a pulse-width modulation (PWM) pin connected to a headphone jack or a wave shield component. The Arduino's PWM (M = 0.6 ms, SD = 0.3) and wave shield (M = 2.6 ms, SD = 0.3) demonstrated significantly lower auditory feedback latencies than the percussion pad (M = 9.1 ms, SD = 2.0), FTAP (M = 14.6 ms, SD = 2.8), and Max/MSP (M = 15.8 ms, SD = 3.4). The PWM and wave shield latencies were also significantly less variable than those from FTAP and Max/MSP. The Arduino missed significantly fewer taps, and recorded fewer superfluous responses, than the percussion pad. The Arduino captured all responses, whereas at lower tapping forces, the percussion pad missed more taps. Regardless of tapping force, the Arduino outperformed the percussion pad. Overall, the Arduino is a high-precision, low-latency, portable, and affordable tool for auditory experiments.

Detection of herpes simplex virus type 2 (HSV-2) -specific cell-mediated immune responses in guinea pigs during latent HSV-2 genital infection.

PubMed

Perry, Clarice L; Banasik, Brianne N; Gorder, Summer R; Xia, Jingya; Auclair, Sarah; Bourne, Nigel; Milligan, Gregg N

2016-12-01

Genital infections with herpes simplex virus type 2 (HSV-2) are a source of considerable morbidity and are a health concern for newborns exposed to virus during vaginal delivery. Additionally, HSV-2 infection diminishes the integrity of the vaginal epithelium resulting in increased susceptibility of individuals to infection with other sexually transmitted pathogens. Understanding immune protection against HSV-2 primary infection and immune modulation of virus shedding events following reactivation of the virus from latency is important for the development of effective prophylactic and therapeutic vaccines. Although the murine model of HSV-2 infection is useful for understanding immunity following immunization, it is limited by the lack of spontaneous reactivation of HSV-2 from latency. Genital infection of guinea pigs with HSV-2 accurately models the disease of humans including the spontaneous reactivation of HSV-2 from latency and provides a unique opportunity to examine virus-host interactions during latency. Although the guinea pig represents an accurate model of many human infections, relatively few reagents are available to study the immunological response to infection. To analyze the cell-mediated immune response of guinea pigs at extended periods of time after establishment of HSV-2 latency, we have modified flow-cytometry based proliferation assays and IFN-γ ELISPOT assays to detect and quantify HSV-specific cell-mediated responses during latent infection of guinea pigs. Here we demonstrate that a combination of proliferation and ELISPOT assays can be used to quantify and characterize effecter function of virus-specific immune memory responses during HSV-latency. Copyright © 2016 Elsevier B.V. All rights reserved.

Patterned light flash evoked short latency activity in the visual system of visually normal and in amblyopic subjects.

PubMed

Sjöström, A; Abrahamsson, M

1994-04-01

In a previous experimental study on anaesthetized cat it was shown that a short latency (35-40 ms) cortical potential changed polarity due to the presence or absence of a pattern in the flash stimulus. The results suggested one pathway of neuronal activation in the cortex to a pattern that was within the level of resolution and another to patterns that were not. It was implied that a similar difference in impulse transmission to pattern and non-pattern stimuli may be recorded in humans. The present paper describes recordings of the short-latency visual evoked response to varying light flash checkerboard pattern stimuli of high intensity in visually normal and amblyopic children and adults. When stimulating the normal eye a visual evoked response potential with a peak latency between 35 to 40 ms showed a polarity change to patterned compared to non-patterned stimulation. The visual evoked response resolution limit could be correlated to a visual acuity of 0.5 and below. In amblyopic eyes the shift in polarity was recorded at the acuity limit level. The latency of the pattern depending potential was increased in patients with amblyopia compared to normal, but not directly related to amblyopic degree. It is concluded that the short latency, visual evoked response that mainly represents the retino-geniculo-cortical activation may be used to estimate visual resolution below 0.5 in acuity level.(ABSTRACT TRUNCATED AT 250 WORDS)

Vestibular short latency responses to pulsed linear acceleration in unanesthetized animals

NASA Technical Reports Server (NTRS)

Jones, T. A.

1992-01-01

Linear acceleration transients were used to elicit vestibular compound action potentials in non-invasively prepared, unanesthetized animals for the first time (chicks, Gallus domesticus, n = 33). Responses were composed of a series of up to 8 dominant peaks occurring within 8 msec of the stimulus. Response amplitudes for 1.0 g stimulus ranged from 1 to 10 microV. A late, slow, triphasic, anesthesia-labile component was identified as a dominant response feature in unanesthetized animals. Amplitudes increased and latencies decreased as stimulus intensity was increased (MANOVA P less than 0.05). Linear regression slope ranges were: amplitudes = 1.0-5.0 microV/g; latencies = -300 to -1100 microseconds/g. Thresholds for single polarity stimuli (0.035 +/- 0.022 g, n = 11) were significantly lower than those of alternating polarity (0.074 +/- 0.028 g, n = 18, P less than 0.001). Bilateral labyrinthectomy eliminated responses whereas bilateral extirpation of cochleae did not significantly change response thresholds. Intense acoustic masking (100/104 dB SL) produced no effect in 2 animals, but did produce small to moderate effects on response amplitudes in 7 others. Changes were attributed to effects on vestibular end organs. Results of unilateral labyrinth blockade (tetrodotoxin) suggest that P1 and N1 preferentially reflect ipsilateral eighth nerve compound action potentials whereas components beyond approximately 2 msec reflect activity from vestibular neurons that depend on both labyrinths. The results demonstrate that short latency vestibular compound action potentials can be measured in unanesthetized, non-invasively prepared animals.

Relationship between median nerve somatosensory evoked potentials and spinal cord injury levels in patients with quadriplegia.

PubMed

de Arruda Serra Gaspar, M I F; Cliquet, A; Fernandes Lima, V M; de Abreu, D C C

2009-05-01

Cross-sectional study. To observe if there is a relationship between the level of injury by the American Spinal Cord Injury Association (ASIA) and cortical somatosensory evoked potential (SSEP) recordings of the median nerve in patients with quadriplegia. Rehabilitation Outpatient Clinic at the university hospital in Brazil. Fourteen individuals with quadriplegia and 8 healthy individuals were evaluated. Electrophysiological assessment of the median nerve was performed by evoked potential equipment. The injury level was obtained by ASIA. N(9), N(13) and N(20) were analyzed based on the presence or absence of responses. The parameters used for analyzing these responses were the latency and the amplitude. Data were analyzed using mixed-effect models. N(9) responses were found in all patients with quadriplegia with a similar latency and amplitude observed in healthy individuals; N(13) responses were not found in any patients with quadriplegia. N(20) responses were not found in C5 patients with quadriplegia but it was present in C6 and C7 patients. Their latencies were similar to healthy individuals (P>0.05) but the amplitudes were decreased (P<0.05). This study suggests that the SSEP responses depend on the injury level, considering that the individuals with C6 and C7 injury levels, both complete and incomplete, presented SSEP recordings in the cortical area. It also showed a relationship between the level of spinal cord injury assessed by ASIA and the median nerve SSEP responses, through the latency and amplitude recordings.

Separating the effects of interreinforcement time and number of interreinforcement responses1

PubMed Central

Neuringer, Allen J.; Schneider, Bruce A.

1968-01-01

The relative importance of interreinforcement time and interreinforcement responses was evaluated by varying each independently. To do this, a blackout was presented after each nonreinforced response under both fixed-ratio and fixed-interval schedules of reinforcement. Manipulating the blackout duration under the fixed-ratio schedule caused interreinforcement time to vary without affecting the number of interreinforcement responses. Pigeons' post-reinforcement and post-blackout response latencies were found to increase linearly with interreinforcement time. Under the fixed-interval schedule, the same blackout manipulations changed the number of interreinforcement responses without affecting interreinforcement time. Post-reinforcement and post-blackout response latencies under this condition were approximately constant. These results suggest that responding is controlled by interreinforcement time and is not influenced by the number of responses emitted between reinforcements. PMID:16811313

Delayed and Temporally Imprecise Neurotransmission in Reorganizing Cortical Microcircuits

PubMed Central

Barnes, Samuel J.; Cheetham, Claire E.; Liu, Yan; Bennett, Sophie H.; Albieri, Giorgia; Jorstad, Anne A.; Knott, Graham W.

2015-01-01

Synaptic neurotransmission is modified at cortical connections throughout life. Varying the amplitude of the postsynaptic response is one mechanism that generates flexible signaling in neural circuits. The timing of the synaptic response may also play a role. Here, we investigated whether weakening and loss of an entire connection between excitatory cortical neurons was foreshadowed in the timing of the postsynaptic response. We made electrophysiological recordings in rat primary somatosensory cortex that was undergoing experience-dependent loss of complete local excitatory connections. The synaptic latency of pyramid–pyramid connections, which typically comprise multiple synapses, was longer and more variable. Connection strength and latency were not correlated. Instead, prolonged latency was more closely related to progression of connection loss. The action potential waveform and axonal conduction velocity were unaffected, suggesting that the altered timing of neurotransmission was attributable to a synaptic mechanism. Modeling studies indicated that increasing the latency and jitter at a subset of synapses reduced the number of action potentials fired by a postsynaptic neuron. We propose that prolonged synaptic latency and diminished temporal precision of neurotransmission are hallmarks of impending loss of a cortical connection. PMID:26085628

Bilateral electromyogram response latency following platform perturbation in unilateral transtibial prosthesis users: influence of weight distribution and limb position.

PubMed

Rusaw, David; Hagberg, Kerstin; Nolan, Lee; Ramstrand, Nerrolyn

2013-01-01

Appropriate muscular response following an external perturbation is essential in preventing falls. Transtibial prosthesis users lack a foot-ankle complex and associated sensorimotor structures on the side with the prosthesis. The effect of this lack on rapid responses of the lower limb to external surface perturbations is unknown. The aim of the present study was to compare electromyogram (EMG) response latencies of otherwise healthy, unilateral, transtibial prosthesis users (n = 23, mean +/- standard deviation [SD] age = 48 +/- 14 yr) and a matched control group (n = 23, mean +/- SD age = 48 +/- 13 yr) following sudden support-surface rotations in the pitch plane (toes-up and toes-down). Perturbations were elicited in various weight-bearing and limb-perturbed conditions. The results indicated that transtibial prosthesis users have delayed responses of multiple muscles of the lower limb following perturbation, both in the intact and residual limbs. Weight-bearing had no influence on the response latency in the residual limb, but did on the intact limb. Which limb received the perturbation was found to influence the muscular response, with the intact limb showing a significantly delayed response when the perturbation was received only on the side with a prosthesis. These delayed responses may represent an increased risk of falling for individuals who use transtibial prostheses.

Long latency postural responses are functionally modified by cognitive set.

PubMed

Beckley, D J; Bloem, B R; Remler, M P; Roos, R A; Van Dijk, J G

1991-10-01

We examined how cognitive set influences the long latency components of normal postural responses in the legs. We disturbed the postural stability of standing human subjects with sudden toe-up ankle rotations. To influence the subjects' cognitive set, we varied the rotation amplitude either predictably (serial 4 degrees versus serial 10 degrees) or unpredictably (random mixture of 4 degrees and 10 degrees). The subjects' responses to these ankle rotations were assessed from the EMG activity of the tibialis anterior, the medial gastrocnemius, and the vastus lateralis muscles of the left leg. The results indicate that, when the rotation amplitude is predictable, only the amplitude of the long latency (LL) response in tibialis anterior and vastus lateralis varied directly with perturbation size. Furthermore, when the rotation amplitude is unpredictable, the central nervous system selects a default amplitude for the LL response in the tibialis anterior. When normal subjects are exposed to 2 perturbation amplitudes which include the potential risk of falling, the default LL response in tibialis anterior appropriately anticipates the larger amplitude perturbation rather than the smaller or an intermediate one.

The development of cortico-motoneuronal projections investigated using magnetic brain stimulation in the infant macaque.

PubMed

Flament, D; Hall, E J; Lemon, R N

1992-02-01

1. The effects of magnetic brain stimulation on electromyographic (EMG) activity recorded from arm and hand muscles have been investigated in five infant and six adult macaque monkeys under ketamine sedation. 2. In the adults, brief, short-latency EMG responses could be readily evoked with magnetic stimuli of 40-50% of the maximum stimulator output (1.5 T). 3. In a cross-sectional study of five infant macaques, it was difficult to evoke EMG responses in young infants (less than 5 months old). Clear short-latency responses were first evoked in an animal 5.75 months old. This change was accompanied by an increase in the probability of occurrence of the responses. 4. In a longitudinal study of two infant monkeys over a period ranging from 2.5 to 14.5 months of age we found that clear short-latency responses were first evoked at 4 and at 5.5 months, respectively. In both animals there was a steady fall in response threshold which reached the adult range at 6.5 and 8 months, respectively. EMG responses in animals older than 8 months were indistinguishable from those in adults. 5. In the longitudinal study we also noted that the latency of EMG responses to magnetic brain stimulation declined with age. Since there were no comparable changes in the peripheral conduction time in these animals, we attribute this result to a decrease in central conduction time. 6. Parallel behavioural observations of the natural behaviour of the same animals within a colony indicated that mature precision movements of the fingers were not used until 5-6 months of age. 7. In two adult monkeys, the latency of EMG responses evoked in the extensor digitorum and first dorsal interosseous muscles by direct stimulation of the corticospinal tract, via electrodes implanted in the medullary pyramids, was found to be 0.7-1.7 ms shorter than that of responses evoked by magnetic stimuli. It is argued that at least the earliest component of these latter responses is conducted over the cortico-motoneuronal pathway. 8. The mechanisms likely to contribute to the late appearance of EMG responses to brain stimulation are discussed. One of these is probably the establishment of mature cortico-motoneuronal connections, which are not present at birth.

Compensation for pitch-shifted auditory feedback during the production of Mandarin tone sequences

NASA Astrophysics Data System (ADS)

Xu, Yi; Larson, Charles R.; Bauer, Jay J.; Hain, Timothy C.

2004-08-01

Recent research has found that while speaking, subjects react to perturbations in pitch of voice auditory feedback by changing their voice fundamental frequency (F0) to compensate for the perceived pitch-shift. The long response latencies (150-200 ms) suggest they may be too slow to assist in on-line control of the local pitch contour patterns associated with lexical tones on a syllable-to-syllable basis. In the present study, we introduced pitch-shifted auditory feedback to native speakers of Mandarin Chinese while they produced disyllabic sequences /ma ma/ with different tonal combinations at a natural speaking rate. Voice F0 response latencies (100-150 ms) to the pitch perturbations were shorter than syllable durations reported elsewhere. Response magnitudes increased from 50 cents during static tone to 85 cents during dynamic tone productions. Response latencies and peak times decreased in phrases involving a dynamic change in F0. The larger response magnitudes and shorter latency and peak times in tasks requiring accurate, dynamic control of F0, indicate this automatic system for regulation of voice F0 may be task-dependent. These findings suggest that auditory feedback may be used to help regulate voice F0 during production of bi-tonal Mandarin phrases.

Auditory Brainstem Evoked Responses in Newborns with Down Syndrome

ERIC Educational Resources Information Center

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

2009-01-01

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…

Neuromagnetic Oscillations Predict Evoked-Response Latency Delays and Core Language Deficits in Autism Spectrum Disorders

ERIC Educational Resources Information Center

Edgar, J. Christopher; Khan, Sarah Y.; Blaskey, Lisa; Chow, Vivian Y.; Rey, Michael; Gaetz, William; Cannon, Katelyn M.; Monroe, Justin F.; Cornew, Lauren; Qasmieh, Saba; Liu, Song; Welsh, John P.; Levy, Susan E.; Roberts, Timothy P. L.

2015-01-01

Previous studies have observed evoked response latency as well as gamma band superior temporal gyrus (STG) auditory abnormalities in individuals with autism spectrum disorders (ASD). A limitation of these studies is that associations between these two abnormalities, as well as the full extent of oscillatory phenomena in ASD in terms of frequency…

The Complete Automation of the Minnesota Multiphasic Personality Inventory and a Study of its Response Latency.

ERIC Educational Resources Information Center

Dunn, Thomas G.; And Others

The feasibility of completely automating the Minnesota Multiphasic Personality Inventory (MMPI) was tested, and item response latencies were compared with other MMPI item characteristics. A total of 26 scales were successfully scored automatically for 165 subjects. The program also typed a Mayo Clinic interpretive report on a computer terminal,…

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

NASA Technical Reports Server (NTRS)

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

1975-01-01

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.

Cerebellar damage diminishes long-latency responses to multijoint perturbations

PubMed Central

Trautman, Paxson; Rasquinha, Russell J.; Bhanpuri, Nasir H.; Scott, Stephen H.; Bastian, Amy J.

2013-01-01

Damage to the cerebellum can cause significant problems in the coordination of voluntary arm movements. One prominent idea is that incoordination stems from an inability to predictively account for the complex mechanical interactions between the arm's several joints. Motivated by growing evidence that corrective feedback control shares important capabilities and neural substrates with feedforward control, we asked whether cerebellar damage impacts feedback stabilization of the multijoint arm appropriate for the arm's intersegmental dynamics. Specifically, we tested whether cerebellar dysfunction impacts the ability of posterior deltoid to incorporate elbow motion in its long-latency response (R2 = 45–75 ms and R3 = 75–100 ms after perturbation) to an unexpected torque perturbation. Healthy and cerebellar-damaged subjects were exposed to a selected pattern of shoulder-elbow displacements to probe the response pattern from this shoulder extensor muscle. The healthy elderly subjects expressed a long-latency response linked to both shoulder and elbow motion, including an increase/decrease in shoulder extensor activity with elbow flexion/extension. Critically, cerebellar-damaged subjects displayed the normal pattern of activity in the R3 period indicating an intact ability to rapidly integrate multijoint motion appropriate to the arm's intersegmental dynamics. However, cerebellar-damaged subjects had a lower magnitude of activity that was specific to the long-latency period (both R2 and R3) and a slightly delayed onset of multijoint sensitivity. Taken together, our results suggest that the basic motor pattern of the long-latency response is housed outside the cerebellum and is scaled by processes within the cerebellum. PMID:23390311

The adequate stimulus for avian short latency vestibular responses to linear translation

NASA Technical Reports Server (NTRS)

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

1998-01-01

Transient linear acceleration stimuli have been shown to elicit eighth nerve vestibular compound action potentials in birds and mammals. The present study was undertaken to better define the nature of the adequate stimulus for neurons generating the response in the chicken (Gallus domesticus). In particular, the study evaluated the question of whether the neurons studied are most sensitive to the maximum level of linear acceleration achieved or to the rate of change in acceleration (da/dt, or jerk). To do this, vestibular response thresholds were measured as a function of stimulus onset slope. Traditional computer signal averaging was used to record responses to pulsed linear acceleration stimuli. Stimulus onset slope was systematically varied. Acceleration thresholds decreased with increasing stimulus onset slope (decreasing stimulus rise time). When stimuli were expressed in units of jerk (g/ms), thresholds were virtually constant for all stimulus rise times. Moreover, stimuli having identical jerk magnitudes but widely varying peak acceleration levels produced virtually identical responses. Vestibular response thresholds, latencies and amplitudes appear to be determined strictly by stimulus jerk magnitudes. Stimulus attributes such as peak acceleration or rise time alone do not provide sufficient information to predict response parameter quantities. Indeed, the major response parameters were shown to be virtually independent of peak acceleration levels or rise time when these stimulus features were isolated and considered separately. It is concluded that the neurons generating short latency vestibular evoked potentials do so as "jerk encoders" in the chicken. Primary afferents classified as "irregular", and which traditionally fall into the broad category of "dynamic" or "phasic" neurons, would seem to be the most likely candidates for the neural generators of short latency vestibular compound action potentials.

Auditory Middle Latency Responses in Chronic Smokers Compared to Nonsmokers: Differential Effects of Stimulus and Age

ERIC Educational Resources Information Center

Ramkissoon, Ishara; Beverly, Brenda L.

2014-01-01

Purpose: Effects of clicks and tonebursts on early and late auditory middle latency response (AMLR) components were evaluated in young and older cigarette smokers and nonsmokers. Method: Participants ( n = 49) were categorized by smoking and age into 4 groups: (a) older smokers, (b) older nonsmokers, (c) young smokers, and (d) young nonsmokers.…

The Effects of Parent-Focused Slow Relaxed Speech Intervention on Articulation Rate, Response Time Latency, and Fluency in Preschool Children Who Stutter

ERIC Educational Resources Information Center

Sawyer, Jean; Matteson, Colleen; Ou, Hua; Nagase, Takahisa

2017-01-01

Purpose: This study investigated the effects of an intervention to reduce caregivers' articulation rates with children who stutter on (a) disfluency, (b) caregiver and child's articulation rates, and (c) caregiver and child's response time latency (RTL). Method: Seventeen caregivers and their preschool children who stuttered participated in a…

Shrapnel: Latency, Mourning and the Suicide of a Parent

ERIC Educational Resources Information Center

Bisagni, Francesco

2012-01-01

The aim of this paper is to describe some acute responses to the suicide of a parent, through the account of the analytic psychotherapy of a latency child who found the body of his dead father. The acute traumatic responses of the child show that the perceptual apparatus, time and space are subverted, while the functioning of the contact barrier…

Role of stretch reflex in voluntary movements. [of human foot

NASA Technical Reports Server (NTRS)

Gottlieb, G. L.; Agarwal, G. C.

1975-01-01

The stretch reflex is often described as a spinal servomechanism, a device for assisting in the regulation of muscle length. Observation of the EMG response to mechanical interruption of voluntary movements fails to demonstrate a significant role for spinal reflexes at 40 msec latency. Two functional responses with latencies of 120 msec and 200 msec, implying supraspinal mediation, are observed.

Theoretical implications of quantitative properties of interval timing and probability estimation in mouse and rat.

PubMed

Kheifets, Aaron; Freestone, David; Gallistel, C R

2017-07-01

In three experiments with mice ( Mus musculus ) and rats (Rattus norvigicus), we used a switch paradigm to measure quantitative properties of the interval-timing mechanism. We found that: 1) Rodents adjusted the precision of their timed switches in response to changes in the interval between the short and long feed latencies (the temporal goalposts). 2) The variability in the timing of the switch response was reduced or unchanged in the face of large trial-to-trial random variability in the short and long feed latencies. 3) The adjustment in the distribution of switch latencies in response to changes in the relative frequency of short and long trials was sensitive to the asymmetry in the Kullback-Leibler divergence. The three results suggest that durations are represented with adjustable precision, that they are timed by multiple timers, and that there is a trial-by-trial (episodic) record of feed latencies in memory. © 2017 Society for the Experimental Analysis of Behavior.

Cue Utilization and Cognitive Load in Novel Task Performance

PubMed Central

Brouwers, Sue; Wiggins, Mark W.; Helton, William; O’Hare, David; Griffin, Barbara

2016-01-01

This study was designed to examine whether differences in cue utilization were associated with differences in performance during a novel, simulated rail control task, and whether these differences reflected a reduction in cognitive load. Two experiments were conducted, the first of which involved the completion of a 20-min rail control simulation that required participants to re-route trains that periodically required a diversion. Participants with a greater level of cue utilization recorded a consistently greater response latency, consistent with a strategy that maintained accuracy, but reduced the demands on cognitive resources. In the second experiment, participants completed the rail task, during which a concurrent, secondary task was introduced. The results revealed an interaction, whereby participants with lesser levels of cue utilization recorded an increase in response latency that exceeded the response latency recorded for participants with greater levels of cue utilization. The relative consistency of response latencies for participants with greater levels of cue utilization, across all blocks, despite the imposition of a secondary task, suggested that those participants with greater levels of cue utilization had adopted a strategy that was effectively minimizing the impact of additional sources of cognitive load on their performance. PMID:27064669

Auditory brainstem activity and development evoked by apical versus basal cochlear implant electrode stimulation in children.

PubMed

Gordon, K A; Papsin, B C; Harrison, R V

2007-08-01

The role of apical versus basal cochlear implant electrode stimulation on central auditory development was examined. We hypothesized that, in children with early onset deafness, auditory development evoked by basal electrode stimulation would differ from that evoked more apically. Responses of the auditory nerve and brainstem, evoked by an apical and a basal implant electrode, were measured over the first year of cochlear implant use in 50 children with early onset severe to profound deafness who used hearing aids prior to implantation. Responses at initial stimulation were of larger amplitude and shorter latency when evoked by the apical electrode. No significant effects of residual hearing or age were found on initial response amplitudes or latencies. With implant use, responses evoked by both electrodes showed decreases in wave and interwave latencies reflecting decreased neural conduction time through the brainstem. Apical versus basal differences persisted with implant experience with one exception; eIII-eV interlatency differences decreased with implant use. Acute stimulation shows prolongation of basally versus apically evoked auditory nerve and brainstem responses in children with severe to profound deafness. Interwave latencies reflecting neural conduction along the caudal and rostral portions of the brainstem decreased over the first year of implant use. Differences in neural conduction times evoked by apical versus basal electrode stimulation persisted in the caudal but not rostral brainstem. Activity-dependent changes of the auditory brainstem occur in response to both apical and basal cochlear implant electrode stimulation.

Development of Auditory Evoked Responses in Normally Developing Preschool Children and Children with Autism Spectrum Disorder.

PubMed

Stephen, Julia M; Hill, Dina E; Peters, Amanda; Flynn, Lucinda; Zhang, Tongsheng; Okada, Yoshio

2017-01-01

The cortical responses to auditory stimuli undergo rapid and dramatic changes during the first 3 years of life in normally developing (ND) children, with decreases in latency and changes in amplitude in the primary peaks. However, most previous studies have focused on children >3 years of age. The analysis of data from the early stages of development is challenging because the temporal pattern of the evoked responses changes with age (e.g., additional peaks emerge with increasing age) and peak latency decreases with age. This study used the topography of the auditory evoked magnetic field (AEF) to identify the auditory components in ND children between 6 and 68 months (n = 48). The latencies of the peaks in the AEF produced by a tone burst (ISI 2 ± 0.2 s) during sleep decreased with age, consistent with previous reports in awake children. The peak latencies of the AEFs in ND children and children with autism spectrum disorder (ASD) were compared. Previous studies indicate that the latencies of the initial components of the auditory evoked potential (AEP) and the AEF are delayed in children with ASD when compared to age-matched ND children >4 years of age. We speculated whether the AEF latencies decrease with age in children diagnosed with ASD as in ND children, but with uniformly longer latencies before the age of about 4 years. Contrary to this hypothesis, the peak latencies did not decrease with age in the ASD group (24-62 months, n = 16) during sleep (unlike in the age-matched controls), although the mean latencies were longer in the ASD group as in previous studies. These results are consistent with previous studies indicating delays in auditory latencies, and they indicate a different maturational pattern in ASD children and ND children. Longitudinal studies are needed to confirm whether the AEF latencies diverge with age, starting at around 3 years, in these 2 groups of children. © 2017 S. Karger AG, Basel.

Affiliation and aggression as related to gender in domestic chicks (Gallus gallus).

PubMed

Vallortigara, G

1992-03-01

Social discrimination in male and female domestic chicks (Gallus gallus) was investigated by using (a) latencies of approach response, (b) simultaneous free choice, and (c) intersubject aggressive-pecking tests. In approach-response tests, females showed shorter latencies when tested with cagemates than when tested with strangers, whereas males showed shorter latencies when tested with strangers than when tested with cagemates. In simultaneous-choice tests, females spent more time near a cagemate, whereas males spent more time near a strange chick. In aggressive-pecking tests, both sexes pecked more at strangers than at cagemates; aggressive pecking at strangers, however, was higher in males than in females. It is argued that gender effects in social discrimination can be accounted for in terms of stronger social attachment in females and aggressive responses in males.

The segment as the minimal planning unit in speech production: evidence based on absolute response latencies.

PubMed

Kawamoto, Alan H; Liu, Qiang; Lee, Ria J; Grebe, Patricia R

2014-01-01

A minimal amount of information about a word must be phonologically and phonetically encoded before a person can begin to utter that word. Most researchers assume that the minimum is the complete word or possibly the initial syllable. However, there is some evidence that the initial segment is sufficient based on longer durations when the initial segment is primed. In two experiments in which the initial segment of a monosyllabic word is primed or not primed, we present additional evidence based on very short absolute response times determined on the basis of acoustic and articulatory onset relative to presentation of the complete target. We argue that the previous failures to find very short absolute response times when the initial segment is primed are due in part to the exclusive use of acoustic onset as a measure of response latency, the exclusion of responses with very short acoustic latencies, the manner of articulation of the initial segment (i.e., plosive vs. nonplosive), and individual differences. Theoretical implications of the segment as the minimal planning unit are considered.

Age-related slowing of response selection and production in a visual choice reaction time task

PubMed Central

Woods, David L.; Wyma, John M.; Yund, E. William; Herron, Timothy J.; Reed, Bruce

2015-01-01

Aging is associated with delayed processing in choice reaction time (CRT) tasks, but the processing stages most impacted by aging have not been clearly identified. Here, we analyzed CRT latencies in a computerized serial visual feature-conjunction task. Participants responded to a target letter (probability 40%) by pressing one mouse button, and responded to distractor letters differing either in color, shape, or both features from the target (probabilities 20% each) by pressing the other mouse button. Stimuli were presented randomly to the left and right visual fields and stimulus onset asynchronies (SOAs) were adaptively reduced following correct responses using a staircase procedure. In Experiment 1, we tested 1466 participants who ranged in age from 18 to 65 years. CRT latencies increased significantly with age (r = 0.47, 2.80 ms/year). Central processing time (CPT), isolated by subtracting simple reaction times (SRT) (obtained in a companion experiment performed on the same day) from CRT latencies, accounted for more than 80% of age-related CRT slowing, with most of the remaining increase in latency due to slowed motor responses. Participants were faster and more accurate when the stimulus location was spatially compatible with the mouse button used for responding, and this effect increased slightly with age. Participants took longer to respond to distractors with target color or shape than to distractors with no target features. However, the additional time needed to discriminate the more target-like distractors did not increase with age. In Experiment 2, we replicated the findings of Experiment 1 in a second population of 178 participants (ages 18–82 years). CRT latencies did not differ significantly in the two experiments, and similar effects of age, distractor similarity, and stimulus-response spatial compatibility were found. The results suggest that the age-related slowing in visual CRT latencies is largely due to delays in response selection and production. PMID:25954175

Reanalysis of cancer mortality in Japanese A-bomb survivors exposed to low doses of radiation: bootstrap and simulation methods

PubMed Central

2009-01-01

Background The International Commission on Radiological Protection (ICRP) recommended annual occupational dose limit is 20 mSv. Cancer mortality in Japanese A-bomb survivors exposed to less than 20 mSv external radiation in 1945 was analysed previously, using a latency model with non-linear dose response. Questions were raised regarding statistical inference with this model. Methods Cancers with over 100 deaths in the 0 - 20 mSv subcohort of the 1950-1990 Life Span Study are analysed with Poisson regression models incorporating latency, allowing linear and non-linear dose response. Bootstrap percentile and Bias-corrected accelerated (BCa) methods and simulation of the Likelihood Ratio Test lead to Confidence Intervals for Excess Relative Risk (ERR) and tests against the linear model. Results The linear model shows significant large, positive values of ERR for liver and urinary cancers at latencies from 37 - 43 years. Dose response below 20 mSv is strongly non-linear at the optimal latencies for the stomach (11.89 years), liver (36.9), lung (13.6), leukaemia (23.66), and pancreas (11.86) and across broad latency ranges. Confidence Intervals for ERR are comparable using Bootstrap and Likelihood Ratio Test methods and BCa 95% Confidence Intervals are strictly positive across latency ranges for all 5 cancers. Similar risk estimates for 10 mSv (lagged dose) are obtained from the 0 - 20 mSv and 5 - 500 mSv data for the stomach, liver, lung and leukaemia. Dose response for the latter 3 cancers is significantly non-linear in the 5 - 500 mSv range. Conclusion Liver and urinary cancer mortality risk is significantly raised using a latency model with linear dose response. A non-linear model is strongly superior for the stomach, liver, lung, pancreas and leukaemia. Bootstrap and Likelihood-based confidence intervals are broadly comparable and ERR is strictly positive by bootstrap methods for all 5 cancers. Except for the pancreas, similar estimates of latency and risk from 10 mSv are obtained from the 0 - 20 mSv and 5 - 500 mSv subcohorts. Large and significant cancer risks for Japanese survivors exposed to less than 20 mSv external radiation from the atomic bombs in 1945 cast doubt on the ICRP recommended annual occupational dose limit. PMID:20003238

The behaviour of the long-latency stretch reflex in patients with Parkinson's disease

PubMed Central

Rothwell, Jc; Obeso, Ja; Traub, Mm; Marsden, Cd

1983-01-01

The size of the long-latency stretch reflex was measured in a proximal (triceps) and distal (flexor pollicis longus) muscle in 47 patients with Parkinson's disease, and was compared with that seen in a group of 12 age-matched normal control subjects. The patients were classified clinically into four groups according to the degree of rigidity at the elbow or tremor. Stretch reflexes were evaluated while the subject was exerting a small force against a constant preload supplied by a torque motor, and the size of the reflex response was measured as fractional increase over basal levels of activity. When stretches were given at random intervals by increasing the force exerted by the motor by a factor of 2 or 3, there was a clear trend for the more severely affected patients to have larger long latency responses in the triceps muscle, although there was no change in the size of the short-latency, spinal component of the response. In contrast, there was no change in the size of the long-latency response of the flexor pollicis longus in any group of patients with Parkinson's disease. Despite any differences in reflex size, the inherent muscle stiffness of both muscles appeared to be normal in all groups of patients with Parkinson's disease, since the displacement trajectory of the limb following the force increase was the same as control values in the short (25 ms) period before reflex compensation could intervene. In 20 of the patients and in seven of the control subjects, servo-controlled, ramp positional disturbances were given to the thumb. Up to a velocity of 300°/s, the size of the long-latency stretch reflex was proportional to the log velocity of stretch. This technique revealed, in both moderately and severely rigid patients, increases in the reflex sensitivity of the flexor pollicis longus, which had not been clear using step torque stretches alone. However, whether using ramp or step displacements, long latency stretch reflex gain was not closely related to rigidity; reflex size was within the normal range in many patients with severe rigidity. Enhanced long latency stretch reflexes thus contribute to, but may not be solely responsible for, rigidity in Parkinson's disease. PMID:6842198

Increased latencies to respond in a judgment bias test are not associated with pessimistic biases in rats.

PubMed

Barker, Timothy Hugh; Howarth, Gordon Stanley; Whittaker, Alexandra Louise

2018-01-01

Extinction of learning is a common, yet under-reported limitation of judgment bias testing methods Repeated exposure to the ambiguous probe of a judgment bias paradigm encourages the animal to cease display of the required behaviours. However, there remains a need to repeatedly test animals to achieve statistical power. A delicate balance therefore needs to be struck between over- and under-exposure of the animals to the test conditions. This study presents the data of rats, a common animal subject of judgment bias testing. Rats were exposed to the ambiguous probe of a common, active-choice judgment bias test for 11 consecutive days. There was a significant increase in the latency to respond to the ambiguous probe following day 8, with no significant increase experienced for either the positive or less-positive probes. Following day 8 there was a significant increase in both optimistic and pessimistic latencies in response to the ambiguous probe. Therefore, repeated exposure to the ambiguous probe caused an increased latency in response even though optimistic interpretations were recorded. This implies that the use of response latency alone as a measure in judgment bias testing can falsely identify pessimism. Researchers should modify experimental design to include both choice and latency measures. Crown Copyright © 2017. Published by Elsevier B.V. All rights reserved.

Differences in receptor-evoked membrane electrical responses in native and mRNA-injected Xenopus oocytes.

PubMed

Oron, Y; Gillo, B; Gershengorn, M C

1988-06-01

Xenopus laevis oocytes are giant cells suitable for studies of plasma membrane receptors and signal transduction pathways because of their capacity to express receptors after injection of heterologous mRNA. We studied depolarizing chloride currents evoked by acetylcholine (AcCho) in native oocytes ("intrinsic AcCho response"), by thyrotropin-releasing hormone (TRH) in oocytes injected with pituitary (GH3) cell RNA ("acquired TRH response"), and by AcCho in oocytes injected with rat brain RNA ("acquired AcCho response"). We found differences in the latencies and patterns of these responses and in the responsiveness to these agonists when applied to the animal or vegetal hemisphere, even though all of the responses are mediated by the same signal transduction pathway. The common intrinsic response to AcCho is characterized by minimal latency (0.86 +/- 0.05 sec), a rapid, transient depolarization followed by a distinct prolonged depolarization, and larger responses obtained after AcCho application at the vegetal rather than the animal hemisphere. By contrast, the acquired responses to TRH and AcCho are characterized by much longer latencies, 9.3 +/- 1.0 and 5.5 +/- 0.8 sec, respectively, and large rapid depolarizations followed by less distinct prolonged depolarizations. The responsiveness on the two hemispheres to TRH and AcCho in mRNA-injected oocytes is opposite to that for the common intrinsic AcCho response in that there is a much greater response when agonist is applied at the animal rather than the vegetal hemisphere. We suggest that the differences in these responses are caused by differences in the intrinsic properties of these receptors. Because different receptors appear to be segregated in the same oocyte in distinct localizations, Xenopus oocytes may be an important model system in which to study receptor sorting in polarized cells.

Functional dissociation between regularity encoding and deviance detection along the auditory hierarchy.

PubMed

Aghamolaei, Maryam; Zarnowiec, Katarzyna; Grimm, Sabine; Escera, Carles

2016-02-01

Auditory deviance detection based on regularity encoding appears as one of the basic functional properties of the auditory system. It has traditionally been assessed with the mismatch negativity (MMN) long-latency component of the auditory evoked potential (AEP). Recent studies have found earlier correlates of deviance detection based on regularity encoding. They occur in humans in the first 50 ms after sound onset, at the level of the middle-latency response of the AEP, and parallel findings of stimulus-specific adaptation observed in animal studies. However, the functional relationship between these different levels of regularity encoding and deviance detection along the auditory hierarchy has not yet been clarified. Here we addressed this issue by examining deviant-related responses at different levels of the auditory hierarchy to stimulus changes varying in their degree of deviation regarding the spatial location of a repeated standard stimulus. Auditory stimuli were presented randomly from five loudspeakers at azimuthal angles of 0°, 12°, 24°, 36° and 48° during oddball and reversed-oddball conditions. Middle-latency responses and MMN were measured. Our results revealed that middle-latency responses were sensitive to deviance but not the degree of deviation, whereas the MMN amplitude increased as a function of deviance magnitude. These findings indicated that acoustic regularity can be encoded at the level of the middle-latency response but that it takes a higher step in the auditory hierarchy for deviance magnitude to be encoded, thus providing a functional dissociation between regularity encoding and deviance detection along the auditory hierarchy. © 2015 Federation of European Neuroscience Societies and John Wiley & Sons Ltd.

Auditory stimuli elicit hippocampal neuronal responses during sleep

PubMed Central

Vinnik, Ekaterina; Antopolskiy, Sergey; Itskov, Pavel M.; Diamond, Mathew E.

2012-01-01

To investigate how hippocampal neurons code behaviorally salient stimuli, we recorded from neurons in the CA1 region of hippocampus in rats while they learned to associate the presence of sound with water reward. Rats learned to alternate between two reward ports at which, in 50% of the trials, sound stimuli were presented followed by water reward after a 3-s delay. Sound at the water port predicted subsequent reward delivery in 100% of the trials and the absence of sound predicted reward omission. During this task, 40% of recorded neurons fired differently according to which of the two reward ports the rat was visiting. A smaller fraction of neurons demonstrated onset response to sound/nosepoke (19%) and reward delivery (24%). When the sounds were played during passive wakefulness, 8% of neurons responded with short latency onset responses; 25% of neurons responded to sounds when they were played during sleep. During sleep the short-latency responses in hippocampus are intermingled with long lasting responses which in the current experiment could last for 1–2 s. Based on the current findings and the results of previous experiments we described the existence of two types of hippocampal neuronal responses to sounds: sound-onset responses with very short latency and longer-lasting sound-specific responses that are likely to be present when the animal is actively engaged in the task. PMID:22754507

Neurophysiological aspects of brainstem processing of speech stimuli in audiometric-normal geriatric population.

PubMed

Ansari, M S; Rangasayee, R; Ansari, M A H

2017-03-01

Poor auditory speech perception in geriatrics is attributable to neural de-synchronisation due to structural and degenerative changes of ageing auditory pathways. The speech-evoked auditory brainstem response may be useful for detecting alterations that cause loss of speech discrimination. Therefore, this study aimed to compare the speech-evoked auditory brainstem response in adult and geriatric populations with normal hearing. The auditory brainstem responses to click sounds and to a 40 ms speech sound (the Hindi phoneme |da|) were compared in 25 young adults and 25 geriatric people with normal hearing. The latencies and amplitudes of transient peaks representing neural responses to the onset, offset and sustained portions of the speech stimulus in quiet and noisy conditions were recorded. The older group had significantly smaller amplitudes and longer latencies for the onset and offset responses to |da| in noisy conditions. Stimulus-to-response times were longer and the spectral amplitude of the sustained portion of the stimulus was reduced. The overall stimulus level caused significant shifts in latency across the entire speech-evoked auditory brainstem response in the older group. The reduction in neural speech processing in older adults suggests diminished subcortical responsiveness to acoustically dynamic spectral cues. However, further investigations are needed to encode temporal cues at the brainstem level and determine their relationship to speech perception for developing a routine tool for clinical decision-making.

An Implicit Measure of Associations with Mental Illness versus Physical Illness: Response Latency Decomposition and Stimuli Differential Functioning in Relation to IAT Order of Associative Conditions and Accuracy

PubMed Central

Mannarini, Stefania; Boffo, Marilisa

2014-01-01

The present study aimed at the definition of a latent measurement dimension underlying an implicit measure of automatic associations between the concept of mental illness and the psychosocial and biogenetic causal explanatory attributes. To this end, an Implicit Association Test (IAT) assessing the association between the Mental Illness and Physical Illness target categories to the Psychological and Biologic attribute categories, representative of the causal explanation domains, was developed. The IAT presented 22 stimuli (words and pictures) to be categorized into the four categories. After 360 university students completed the IAT, a Many-Facet Rasch Measurement (MFRM) modelling approach was applied. The model specified a person latency parameter and a stimulus latency parameter. Two additional parameters were introduced to denote the order of presentation of the task associative conditions and the general response accuracy. Beyond the overall definition of the latent measurement dimension, the MFRM was also applied to disentangle the effect of the task block order and the general response accuracy on the stimuli response latency. Further, the MFRM allowed detecting any differential functioning of each stimulus in relation to both block ordering and accuracy. The results evidenced: a) the existence of a latency measurement dimension underlying the Mental Illness versus Physical Illness - Implicit Association Test; b) significant effects of block order and accuracy on the overall latency; c) a differential functioning of specific stimuli. The results of the present study can contribute to a better understanding of the functioning of an implicit measure of semantic associations with mental illness and give a first blueprint for the examination of relevant issues in the development of an IAT. PMID:25000406

An implicit measure of associations with mental illness versus physical illness: response latency decomposition and stimuli differential functioning in relation to IAT order of associative conditions and accuracy.

PubMed

Mannarini, Stefania; Boffo, Marilisa

2014-01-01

The present study aimed at the definition of a latent measurement dimension underlying an implicit measure of automatic associations between the concept of mental illness and the psychosocial and biogenetic causal explanatory attributes. To this end, an Implicit Association Test (IAT) assessing the association between the Mental Illness and Physical Illness target categories to the Psychological and Biologic attribute categories, representative of the causal explanation domains, was developed. The IAT presented 22 stimuli (words and pictures) to be categorized into the four categories. After 360 university students completed the IAT, a Many-Facet Rasch Measurement (MFRM) modelling approach was applied. The model specified a person latency parameter and a stimulus latency parameter. Two additional parameters were introduced to denote the order of presentation of the task associative conditions and the general response accuracy. Beyond the overall definition of the latent measurement dimension, the MFRM was also applied to disentangle the effect of the task block order and the general response accuracy on the stimuli response latency. Further, the MFRM allowed detecting any differential functioning of each stimulus in relation to both block ordering and accuracy. The results evidenced: a) the existence of a latency measurement dimension underlying the Mental Illness versus Physical Illness - Implicit Association Test; b) significant effects of block order and accuracy on the overall latency; c) a differential functioning of specific stimuli. The results of the present study can contribute to a better understanding of the functioning of an implicit measure of semantic associations with mental illness and give a first blueprint for the examination of relevant issues in the development of an IAT.

Common neural structures activated by epidural and transcutaneous lumbar spinal cord stimulation: Elicitation of posterior root-muscle reflexes

PubMed Central

Freundl, Brigitta; Binder, Heinrich; Minassian, Karen

2018-01-01

Epidural electrical stimulation of the lumbar spinal cord is currently regaining momentum as a neuromodulation intervention in spinal cord injury (SCI) to modify dysregulated sensorimotor functions and augment residual motor capacity. There is ample evidence that it engages spinal circuits through the electrical stimulation of large-to-medium diameter afferent fibers within lumbar and upper sacral posterior roots. Recent pilot studies suggested that the surface electrode-based method of transcutaneous spinal cord stimulation (SCS) may produce similar neuromodulatory effects as caused by epidural SCS. Neurophysiological and computer modeling studies proposed that this noninvasive technique stimulates posterior-root fibers as well, likely activating similar input structures to the spinal cord as epidural stimulation. Here, we add a yet missing piece of evidence substantiating this assumption. We conducted in-depth analyses and direct comparisons of the electromyographic (EMG) characteristics of short-latency responses in multiple leg muscles to both stimulation techniques derived from ten individuals with SCI each. Post-activation depression of responses evoked by paired pulses applied either epidurally or transcutaneously confirmed the reflex nature of the responses. The muscle responses to both techniques had the same latencies, EMG peak-to-peak amplitudes, and waveforms, except for smaller responses with shorter onset latencies in the triceps surae muscle group and shorter offsets of the responses in the biceps femoris muscle during epidural stimulation. Responses obtained in three subjects tested with both methods at different time points had near-identical waveforms per muscle group as well as same onset latencies. The present results strongly corroborate the activation of common neural input structures to the lumbar spinal cord—predominantly primary afferent fibers within multiple posterior roots—by both techniques and add to unraveling the basic mechanisms underlying electrical SCS. PMID:29381748

Age-related differences in trunk muscle reflexive behaviors.

PubMed

Shojaei, Iman; Nussbaum, Maury A; Bazrgari, Babak

2016-10-03

Reports of larger passive and similar intrinsic trunk stiffness in older vs. younger populations suggest a diminishing demand for reflexive contributions of trunk muscles to spinal stability with aging. It remains unclear, though, whether such diminishing demands result in deterioration of trunk muscle reflexive behaviors. A cross-sectional study was completed to assess age-related differences in the latency and likelihood of trunk muscle reflexive responses to sudden perturbations. Sixty healthy individuals, aged 20-70 years, were recruited to form five equal-sized and gender-balanced age groups. Using a displacement-control, sudden perturbation paradigm, the latency and likelihood of trunk muscle reflexive responses to sudden perturbations were estimated, and the influences of age, gender, and level of effort (20% versus 30% of maximum voluntary exertion-MVE) were evaluated. There were no consistent age-related differences found in any of the measures of trunk muscle reflexive behavior. However, the latency of muscle response to perturbation was generally higher among older individuals, and this difference was significant in the condition involving 30% MVE effort. With an increase in level of effort (from 20% to 30% of MVE), there was a ~7% increase in the latency of trunk muscle responses to anteriorly-directed perturbations as well as ~ 15% (21%) decrease (increase) in response likelihood during anteriorly (posteriorly) directed perturbations. Furthermore, the reflexive response likelihood of trunk muscles was 28% (58%) larger (smaller) in female vs. male participants during anteriorly (posteriorly) directed perturbations. Our results did not, in general, support the hypothesis of an age-related decay in reflexive trunk muscle behaviors. Larger reflexive responses were associated with lower trunk intrinsic stiffness among females and during a lower level of effort, suggesting a secondary role for reflexive responses in spinal stability. Such secondary compensatory responses appear, however, to be consistent over a wide age range. Copyright © 2016 Elsevier Ltd. All rights reserved.

Recovery cycle times of inferior colliculus neurons in the awake bat measured with spike counts and latencies

PubMed Central

Sayegh, Riziq; Aubie, Brandon; Fazel-Pour, Siavosh; Faure, Paul A.

2012-01-01

Neural responses in the mammalian auditory midbrain (inferior colliculus; IC) arise from complex interactions of synaptic excitation, inhibition, and intrinsic properties of the cell. Temporally selective duration-tuned neurons (DTNs) in the IC are hypothesized to arise through the convergence of excitatory and inhibitory synaptic inputs offset in time. Synaptic inhibition can be inferred from extracellular recordings by presenting pairs of pulses (paired tone stimulation) and comparing the evoked responses of the cell to each pulse. We obtained single unit recordings from the IC of the awake big brown bat (Eptesicus fuscus) and used paired tone stimulation to measure the recovery cycle times of DTNs and non-temporally selective auditory neurons. By systematically varying the interpulse interval (IPI) of the paired tone stimulus, we determined the minimum IPI required for a neuron's spike count or its spike latency (first- or last-spike latency) in response to the second tone to recover to within ≥50% of the cell's baseline count or to within 1 SD of it's baseline latency in response to the first tone. Recovery times of shortpass DTNs were significantly shorter than those of bandpass DTNs, and recovery times of bandpass DTNs were longer than allpass neurons not selective for stimulus duration. Recovery times measured with spike counts were positively correlated with those measured with spike latencies. Recovery times were also correlated with first-spike latency (FSL). These findings, combined with previous studies on duration tuning in the IC, suggest that persistent inhibition is a defining characteristic of DTNs. Herein, we discuss measuring recovery times of neurons with spike counts and latencies. We also highlight how persistent inhibition could determine neural recovery times and serve as a potential mechanism underlying the precedence effect in humans. Finally, we explore implications of recovery times for DTNs in the context of bat hearing and echolocation. PMID:22933992

Central Auditory Maturation and Behavioral Outcome in Children with Auditory Neuropathy Spectrum Disorder who Use Cochlear Implants

PubMed Central

Cardon, Garrett; Sharma, Anu

2013-01-01

Objective We examined cortical auditory development and behavioral outcomes in children with ANSD fitted with cochlear implants (CI). Design Cortical maturation, measured by P1 cortical auditory evoked potential (CAEP) latency, was regressed against scores on the Infant Toddler Meaningful Auditory Integration Scale (IT-MAIS). Implantation age was also considered in relation to CAEP findings. Study Sample Cross-sectional and longitudinal samples of 24 and 11 children, respectively, with ANSD fitted with CIs. Result P1 CAEP responses were present in all children after implantation, though previous findings suggest that only 50-75% of ANSD children with hearing aids show CAEP responses. P1 CAEP latency was significantly correlated with participants' IT-MAIS scores. Furthermore, more children implanted before age two years showed normal P1 latencies, while those implanted later mainly showed delayed latencies. Longitudinal analysis revealed that most children showed normal or improved cortical maturation after implantation. Conclusion Cochlear implantation resulted in measureable cortical auditory development for all children with ANSD. Children fitted with CIs under age two years were more likely to show age-appropriate CAEP responses within 6 months after implantation, suggesting a possible sensitive period for cortical auditory development in ANSD. That CAEP responses were correlated with behavioral outcome highlights their clinical decision-making utility. PMID:23819618

Flexible and inflexible response components: a Stroop study with typewritten output.

PubMed

Damian, Markus F; Freeman, Norman H

2008-05-01

Two experiments were directed at investigating the relationship between response selection and execution in typewriting, and specifically the extent to which concurrent processing takes place. In a Stroop paradigm adapted from [Logan, G. D., & Zbrodoff, N. J. (1998). Stroop-type interference: Congruity effects in colour naming with typewritten responses. Journal of Experimental Psychology: Human Perception and Performance, 24, 978-992], participants typed the names of colour patches with incongruent, congruent, or neutral distractors presented at various stimulus-onset asynchronies. Experiment 1 showed Stroop interference and facilitation for initial keystroke latencies and errors, contrasting with response durations (a measure of response execution) being unaffected by Stroop manipulation. Experiment 2 showed that all three measures were responsive to time pressure; again, Stroop effects were confined to latencies and errors only. The observation that response duration is both flexible under time pressure and protected from response competition, may imply either that response execution is structurally segregated from earlier processing stages, or that encapsulation develops during the acquisition of typing skills.

Perceptual latency priming by masked and unmasked stimuli: evidence for an attentional interpretation.

PubMed

Scharlau, Ingrid; Neumann, Odmar

2003-08-01

Four experiments investigated the influence of a metacontrast-masked prime on temporal order judgments. The main results were (1) that a masked prime reduced the latency of the mask's conscious perception (perceptual latency priming), (2) that this effect was independent of whether the prime suffered strong or weak masking, (3) that it was unaffected by the degree of visual similarity between the prime and the mask, and that (4) there was no difference between congruent and incongruent primes. Finding (1) suggests that location cueing affects not only response times but also the latency of conscious perception. (2) The finding that priming was unaffected by the prime's detectability argues against a response bias interpretation of this effect. (3) Since visual similarity had no effect on the prime's efficiency, it is unlikely that sensory priming was involved. (4) The lack of a divergence between the effects of congruent and incongruent primes implies a functional difference between the judgments in the temporal order judgment task and speeded responses that have demonstrated differential effects of congruent and incongruent primes (e.g., Klotz & Neumann, 1999). These results can best be interpreted by assuming that the prime affects perceptual latency by initiating a shift of attention, as suggested by the Asynchronous Updating Model (AUM; Neumann 1978, 1982).

Air Traffic Controller Performance and Acceptability of Multiple UAS in a Simulated NAS Environment

NASA Technical Reports Server (NTRS)

Vu, Kim-Phuong L.; Strybel, Thomas; Chiappe, Dan; Morales, Greg; Battiste, Vernol; Shively, Robert Jay

2014-01-01

Previously, we showed that air traffic controllers (ATCos) rated UAS pilot verbal response latencies as acceptable when a 1.5 s delay was added to the UAS pilot responses, but a 5 s delay was rated as mostly unacceptable. In the present study we determined whether a 1.5 s added delay in the UAS pilots' verbal communications would affect ATCos interactions with UAS and other conventional aircraft when the number and speed of the UAS were manipulated. Eight radar-certified ATCos participated in this simulation. The ATCos managed a medium altitude sector containing arrival aircraft, en route aircraft, and one to four UAS. The UAS were conducting a surveillance mission and flew at either a "slow" or "fast" speed. We measured both UAS and conventional pilots' verbal communication latencies, and obtained ATCos' acceptability ratings for these latencies. Although the UAS pilot response latencies were longer than those of conventional pilots, the ATCos rated UAS pilot verbal communication latencies to be as acceptable as those of conventional pilots. Because the overall traffic load within the sector was held constant, ATCos only performed slightly worse when multiple UAS were in their sector compared to when only one UAS was in the sector. Implications of these findings for UAS integration in the NAS are discussed.

Handling qualities effects of display latency

NASA Technical Reports Server (NTRS)

King, David W.

1993-01-01

Display latency is the time delay between aircraft response and the corresponding response of the cockpit displays. Currently, there is no explicit specification for allowable display lags to ensure acceptable aircraft handling qualities in instrument flight conditions. This paper examines the handling qualities effects of display latency between 70 and 400 milliseconds for precision instrument flight tasks of the V-22 Tiltrotor aircraft. Display delay effects on the pilot control loop are analytically predicted through a second order pilot crossover model of the V-22 lateral axis, and handling qualities trends are evaluated through a series of fixed-base piloted simulation tests. The results show that the effects of display latency for flight path tracking tasks are driven by the stability characteristics of the attitude control loop. The data indicate that the loss of control damping due to latency can be simply predicted from knowledge of the aircraft's stability margins, control system lags, and required control bandwidths. Based on the relationship between attitude control damping and handling qualities ratings, latency design guidelines are presented. In addition, this paper presents a design philosophy, supported by simulation data, for using flight director display augmentation to suppress the effects of display latency for delays up to 300 milliseconds.

Modelling Transposition Latencies: Constraints for Theories of Serial Order Memory

ERIC Educational Resources Information Center

Farrell, Simon; Lewandowsky, Stephan

2004-01-01

Several competing theories of short-term memory can explain serial recall performance at a quantitative level. However, most theories to date have not been applied to the accompanying pattern of response latencies, thus ignoring a rich and highly diagnostic aspect of performance. This article explores and tests the error latency predictions of…

Using photographs to study animal social cognition and behaviour: Do capuchins' responses to photos reflect reality?

PubMed

Morton, F Blake; Brosnan, Sarah F; Prétôt, Laurent; Buchanan-Smith, Hannah M; O'Sullivan, Eoin; Stocker, Martina; D'Mello, Daniel; Wilson, Vanessa A D

2016-03-01

Behavioural responses to photos are often used to infer what animals understand about their social environment, but are rarely validated against the same stimuli in real life. If subjects' responses to photos do not reflect responses to the same live stimuli, it is difficult to conclude what happens in reality based on photo responses alone. We compared capuchins' responses to photos versus live stimuli in an identical scenario within research cubicles. Subjects had the opportunity to approach food placed in front of an alpha group member and, in a separate condition, photos depicting the same individual. Subjects' latencies to approach food when placed in front of the real alpha negatively correlated with time subjects spent in close proximity to the alpha in their main enclosure. We therefore predicted subjects' latencies to approach food in the presence of photos would positively correlate with their latencies to approach food in the presence of the real alpha inside the cubicles, but negatively correlate with time they spent in proximity to the alpha in their enclosure. Neither prediction was supported. While not necessarily surprising, we explain why these results should be an important reminder that care is needed when interpreting results from photo studies. Copyright © 2015 Elsevier B.V. All rights reserved.

Latency-Based and Psychophysiological Measures of Sexual Interest Show Convergent and Concurrent Validity.

PubMed

Ó Ciardha, Caoilte; Attard-Johnson, Janice; Bindemann, Markus

2018-04-01

Latency-based measures of sexual interest require additional evidence of validity, as do newer pupil dilation approaches. A total of 102 community men completed six latency-based measures of sexual interest. Pupillary responses were recorded during three of these tasks and in an additional task where no participant response was required. For adult stimuli, there was a high degree of intercorrelation between measures, suggesting that tasks may be measuring the same underlying construct (convergent validity). In addition to being correlated with one another, measures also predicted participants' self-reported sexual interest, demonstrating concurrent validity (i.e., the ability of a task to predict a more validated, simultaneously recorded, measure). Latency-based and pupillometric approaches also showed preliminary evidence of concurrent validity in predicting both self-reported interest in child molestation and viewing pornographic material containing children. Taken together, the study findings build on the evidence base for the validity of latency-based and pupillometric measures of sexual interest.

EMG responses to maintain stance during multidirectional surface translations

NASA Technical Reports Server (NTRS)

Henry, S. M.; Fung, J.; Horak, F. B.; Peterson, B. W. (Principal Investigator)

1998-01-01

To characterize muscle synergy organization underlying multidirectional control of stance posture, electromyographic activity was recorded from 11 lower limb and trunk muscles of 7 healthy subjects while they were subjected to horizontal surface translations in 12 different, randomly presented directions. The latency and amplitude of muscle responses were quantified for each perturbation direction. Tuning curves for each muscle were examined to relate the amplitude of the muscle response to the direction of surface translation. The latencies of responses for the shank and thigh muscles were constant, regardless of perturbation direction. In contrast, the latencies for another thigh [tensor fascia latae (TFL)] and two trunk muscles [rectus abdominis (RAB) and erector spinae (ESP)] were either early or late, depending on the perturbation direction. These three muscles with direction-specific latencies may play different roles in postural control as prime movers or as stabilizers for different translation directions, depending on the timing of recruitment. Most muscle tuning curves were within one quadrant, having one direction of maximal activity, generally in response to diagonal surface translations. Two trunk muscles (RAB and ESP) and two lower limb muscles (semimembranosus and peroneus longus) had bipolar tuning curves, with two different directions of maximal activity, suggesting that these muscle can play different roles as part of different synergies, depending on translation direction. Muscle tuning curves tended to group into one of three regions in response to 12 different directions of perturbations. Two muscles [rectus femoris (RFM) and TFL] were maximally active in response to lateral surface translations. The remaining muscles clustered into one of two diagonal regions. The diagonal regions corresponded to the two primary directions of active horizontal force vector responses. Two muscles (RFM and adductor longus) were maximally active orthogonal to their predicted direction of maximal activity based on anatomic orientation. Some of the muscles in each of the synergic regions were not anatomic synergists, suggesting a complex central organization for recruitment of muscles. The results suggest that neither a simple reflex mechanism nor a fixed muscle synergy organization is adequate to explain the muscle activation patterns observed in this postural control task. Our results are consistent with a centrally mediated pattern of muscle latencies combined with peripheral influence on muscle magnitude. We suggest that a flexible continuum of muscle synergies that are modifiable in a task-dependent manner be used for equilibrium control in stance.

Intraoperative monitoring of the recurrent laryngeal nerve by vagal nerve stimulation in thyroid surgery.

PubMed

Farizon, Brigitte; Gavid, Marie; Karkas, Alexandre; Dumollard, Jean-Marc; Peoc'h, Michel; Prades, Jean-Michel

2017-01-01

The aim of the present study was to evaluate the thyroarytenoid muscle response during bilateral thyroid surgery using vagal nerve stimulation. 195 patients (390 nerves at risk) underwent a total thyroidectomy. The recurrent laryngeal nerve's function was checked by analyzing the amplitude and the latency of the thyroarytenoid muscle's responses after a vagal nerve's stimulation (0.5 and 1 mA) using the NIM3 Medtronic system. All patients were submitted to preoperative and postoperative laryngoscopy. 20 patients get no thyroarytenoid muscle response to the vagal nerve stimulation, and 14 postoperative recurrent laryngeal nerve palsies were confirmed (3.8 %). Two palsies were present after 6 months (0.51 %). All the patients with muscle's response have normal mobility vocal fold. The test sensitivity was 100 % and the test specificity was 98 %. Physiologically, the mean latencies of the muscular potentials for the right RLN were, respectively, 3.89 and 3.83 ms (p > 0.05) for the stimulation at 0.5 and 1 mA. The mean latencies for the left RLN were, respectively, 6.25 and 6.22 ms for the stimulation at 0.5 and 1 mA (p > 0.05). The difference of the latencies between the right and the left nerve was 2.30 ms (1.75-3.25 ms) with a stimulation of 0.5 or 1 mA (p < 0.05). Thyroarytenoid muscle's response via a vagal nerve stimulation showed a functional asymmetry of the laryngeal adduction with a faster right response. Surgically, this method can predict accurately an immediate postoperative vocal folds function in patients undergoing a bilateral thyroid surgery.

Increased reaction time variability in attention-deficit hyperactivity disorder as a response-related phenomenon: evidence from single-trial event-related potentials.

PubMed

Saville, Christopher W N; Feige, Bernd; Kluckert, Christian; Bender, Stephan; Biscaldi, Monica; Berger, Andrea; Fleischhaker, Christian; Henighausen, Klaus; Klein, Christoph

2015-07-01

Increased intra-subject variability (ISV) in reaction times (RTs) is a promising endophenotype for attention-deficit hyperactivity disorder (ADHD) and among the most robust hallmarks of the disorder. ISV has been assumed to represent an attentional deficit, either reflecting lapses in attention or increased neural noise. Here, we use an innovative single-trial event-related potential approach to assess whether the increased ISV associated with ADHD is indeed attributable to attention, or whether it is related to response-related processing. We measured electroencephalographic responses to working memory oddball tasks in patients with ADHD (N = 20, aged 11.3 ± 1.1) and healthy controls (N = 25, aged 11.7 ± 1.1), and analysed these data with a recently developed method of single-trial event-related potential analysis. Estimates of component latency variability were computed for the stimulus-locked and response-locked forms of the P3b and the lateralised readiness potential (LRP). ADHD patients showed significantly increased ISV in behavioural ISV. This increased ISV was paralleled by an increase in variability in response-locked event-related potential latencies, while variability in stimulus-locked latencies was equivalent between groups. This result held across the P3b and LRP. Latency of all components predicted RTs on a single-trial basis, confirming that all were relevant for speed of processing. These data suggest that the increased ISV found in ADHD could be associated with response-end, rather than stimulus-end processes, in contrast to prevailing conceptions about the endophenotype. This mental chronometric approach may also be useful for exploring whether the existing lack of specificity of ISV to particular psychiatric conditions can be improved upon. © 2014 Association for Child and Adolescent Mental Health.

Reflex responses of lip muscles in young and older women.

PubMed

Wohlert, A B

1996-06-01

The perioral reflex in response to innocuous mechanical stimulation of the lip vermilion was studied in 20 young and 20 older women. Responses to stimuli at the right and left sides of both the upper and lower lips were recorded. Results show significant specificity of response, especially for upper lip sites. Reflex response at the site of stimulation was greatest in amplitude and shortest in latency, followed by response at sites ipsilateral to the site of stimulation. Younger subjects showed greater localizing tendency than older subjects. Stimulation was significantly less likely to produce a reflex response in the older group. When reflex responses did occur, they were significantly lower in amplitude and longer in latency than the responses of the younger group. Nonetheless, reflex responses were common in both groups, with responses at the site of stimulation occurring 78% of the time in older women and 90% of the time in younger women. Every participant showed at least one reflex response to lip stimulation. Results suggest decreasing complexity of synaptic drive to the perioral system in old age but also show that reflexive response does not deteriorate completely, remaining an available element for motor control in normal older women.

Response latencies are alive and well for identifying fakers on a self-report personality inventory: A reconsideration of van Hooft and Born (2012).

PubMed

Holden, Ronald R; Lambert, Christine E

2015-12-01

Van Hooft and Born (Journal of Applied Psychology 97:301-316, 2012) presented data challenging both the correctness of a congruence model of faking on personality test items and the relative merit (i.e., effect size) of response latencies for identifying fakers. We suggest that their analysis of response times was suboptimal, and that it followed neither from a congruence model of faking nor from published protocols on appropriately filtering the noise in personality test item answering times. Using new data and following recommended analytic procedures, we confirmed the relative utility of response times for identifying personality test fakers, and our obtained results, again, reinforce a congruence model of faking.

The Schultz MIDI Benchmarking Toolbox for MIDI interfaces, percussion pads, and sound cards.

PubMed

Schultz, Benjamin G

2018-04-17

The Musical Instrument Digital Interface (MIDI) was readily adopted for auditory sensorimotor synchronization experiments. These experiments typically use MIDI percussion pads to collect responses, a MIDI-USB converter (or MIDI-PCI interface) to record responses on a PC and manipulate feedback, and an external MIDI sound module to generate auditory feedback. Previous studies have suggested that auditory feedback latencies can be introduced by these devices. The Schultz MIDI Benchmarking Toolbox (SMIDIBT) is an open-source, Arduino-based package designed to measure the point-to-point latencies incurred by several devices used in the generation of response-triggered auditory feedback. Experiment 1 showed that MIDI messages are sent and received within 1 ms (on average) in the absence of any external MIDI device. Latencies decreased when the baud rate increased above the MIDI protocol default (31,250 bps). Experiment 2 benchmarked the latencies introduced by different MIDI-USB and MIDI-PCI interfaces. MIDI-PCI was superior to MIDI-USB, primarily because MIDI-USB is subject to USB polling. Experiment 3 tested three MIDI percussion pads. Both the audio and MIDI message latencies were significantly greater than 1 ms for all devices, and there were significant differences between percussion pads and instrument patches. Experiment 4 benchmarked four MIDI sound modules. Audio latencies were significantly greater than 1 ms, and there were significant differences between sound modules and instrument patches. These experiments suggest that millisecond accuracy might not be achievable with MIDI devices. The SMIDIBT can be used to benchmark a range of MIDI devices, thus allowing researchers to make informed decisions when choosing testing materials and to arrive at an acceptable latency at their discretion.

Age-related changes in human posture control: Motor coordination tests

NASA Technical Reports Server (NTRS)

Peterka, R. J.; Black, F. O.

1989-01-01

Postural responses to support surface displacements were measured in 214 normal human subjects ranging in age from 7 to 81 years. Motor tests measured leg muscle Electromyography (EMG) latencies, body sway, and the amplitude and timing of changes in center of pressure displacements in response to sudden forward and backward horizontal translations of the support surface upon which the subjects stood. There were small increases in both EMG latencies and the time to reach the peak amplitude of center of pressure responses with increasing age. The amplitude of center of pressure responses showed little change with age if the amplitude measures were normalized by a factor related to subject height. In general, postural responses to sudden translations showed minimal changes with age, and all age related trends which were identified were small relative to the variability within the population.

The dynamic response of visual accommodation over a seven-day period

NASA Technical Reports Server (NTRS)

Randle, R. J.; Murphy, M. R.

1974-01-01

Four college students, ranging in age from 18 to 21 years, were tested on their dynamic, monocular accommodation responses to a square wave stimulus and sine waves of two frequencies. The tests were conducted over a period of seven days in a controlled environment, each subject being tested once every three hours. Latency, magnitude, velocity, gain and phase lag of the responses were measured, and means and standard deviations were computed. The latency of response was stable throughout and agreed fairly well with previous studies. The response magnitude was relatively stable. Three of the subjects had higher velocities on receding targets; one was faster on approaching targets. The group mean velocity increased over the seven days of the study. In keeping with the trend to faster dynamics over the seven days, both gain and phase lag improved.

Signal, noise, and variation in neural and sensory-motor latency

PubMed Central

Lee, Joonyeol; Joshua, Mati; Medina, Javier F.; Lisberger, Stephen G.

2016-01-01

Analysis of the neural code for sensory-motor latency in smooth pursuit eye movements reveals general principles of neural variation and the specific origin of motor latency. The trial-by-trial variation in neural latency in MT comprises: a shared component expressed as neuron-neuron latency correlations; and an independent component that is local to each neuron. The independent component arises heavily from fluctuations in the underlying probability of spiking with an unexpectedly small contribution from the stochastic nature of spiking itself. The shared component causes the latency of single neuron responses in MT to be weakly predictive of the behavioral latency of pursuit. Neural latency deeper in the motor system is more strongly predictive of behavioral latency. A model reproduces both the variance of behavioral latency and the neuron-behavior latency correlations in MT if it includes realistic neural latency variation, neuron-neuron latency correlations in MT, and noisy gain control downstream from MT. PMID:26971946

Supraspinal control of automatic postural responses in people with multiple sclerosis.

PubMed

Peterson, D S; Gera, G; Horak, F B; Fling, B W

2016-06-01

The neural underpinnings of delayed automatic postural responses in people with multiple sclerosis (PwMS) are unclear. We assessed whether white matter pathways of two supraspinal regions (the cortical proprioceptive Broadman's Area-3; and the balance/locomotor-related pedunculopontine nucleus) were related to delayed postural muscle response latencies in response to external perturbations. 19 PwMS (48.8±11.4years; EDSS=3.5 (range: 2-4)) and 12 healthy adults (51.7±12.2years) underwent 20 discrete, backward translations of a support surface. Onset latency of agonist (medial-gastrocnemius) and antagonist (tibialis anterior) muscles were assessed. Diffusion tensor imaging assessed white-matter integrity (i.e. radial diffusivity) of cortical proprioceptive and balance/locomotor-related tracts. Latency of the tibialis anterior, but not medial gastrocnemius was larger in PwMS than control subjects (p=0.012 and 0.071, respectively). Radial diffusivity of balance/locomotor tracts was higher (worse) in PwMS than control subjects (p=0.004), and was significantly correlated with tibialis (p=0.002), but not gastrocnemius (p=0.06) onset latency. Diffusivity of cortical proprioceptive tracts was not correlated with muscle onset. Lesions in supraspinal structures including the pedunculopontine nucleus balance/locomotor network may contribute to delayed onset of postural muscle activity in PwMS, contributing to balance deficits in PwMS. Published by Elsevier B.V.

Word Association in L1 and L2: An Exploratory Study of Response Types, Response Times, and Interlingual Mediation

ERIC Educational Resources Information Center

Fitzpatrick, Tess; Izura, Cristina

2011-01-01

Word association responses in first-language (L1) Spanish and second-language (L2) English were investigated by means of response latencies and types of associative response produced. The primary aims were to establish whether (a) some response types are produced more often or faster than others, (b) participants' L2 response time profiles mirror…

ONTOGENY OF THE ACOUSTIC STARTLE RESPONSE AND SENSITIZATION TO BACKGROUND NOISE IN THE RAT (JOURNAL VERSION)

EPA Science Inventory

The purpose of the study was to characterize the ontogeny of the acoustic startle response (ASR), and response sensitization to background noise, in preweanling rats. With constant low-level (45 dB) background noise, response latency decreased steadily with age, whereas, both res...

Brain stem auditory evoked responses in human infants and adults

NASA Technical Reports Server (NTRS)

Hecox, K.; Galambos, R.

1974-01-01

Brain stem evoked potentials were recorded by conventional scalp electrodes in infants (3 weeks to 3 years of age) and adults. The latency of one of the major response components (wave V) is shown to be a function both of click intensity and the age of the subject; this latency at a given signal strength shortens postnatally to reach the adult value (about 6 msec) by 12 to 18 months of age. The demonstrated reliability and limited variability of these brain stem electrophysiological responses provide the basis for an optimistic estimate of their usefulness as an objective method for assessing hearing in infants and adults.

Occlusion therapy improves phase-alignment of the cortical response in amblyopia.

PubMed

Kelly, John P; Tarczy-Hornoch, Kristina; Herlihy, Erin; Weiss, Avery H

2015-09-01

The visual evoked potential (VEP) generated by the amblyopic visual system demonstrates reduced amplitude, prolonged latency, and increased variation in response timing (phase-misalignment). This study examined VEPs before and after occlusion therapy (OT) and whether phase-misalignment can account for the amblyopic VEP deficits. VEPs were recorded to 0.5-4cycles/degree gratings in 10 amblyopic children (2-6years age) before and after OT. Phase-misalignment was measured by Fourier analysis across a limited bandwidth. Signal-to-noise ratios (SNRs) were estimated from amplitude and phase synchrony in the Fourier domain. Responses were compared to VEPs corrected for phase-misalignment (individual epochs shifted in time to correct for the misalignment). Before OT, amblyopic eyes (AE) had significantly more phase-misalignment, latency prolongation, and lower SNR relative to the fellow eye. Phase-misalignment contributed significantly to low SNR but less so to latency delay in the AE. After OT, phase-alignment improved, SNR improved and latency shortened in the AE. Raw averaged waveforms from the AE improved after OT, primarily at higher spatial frequencies. Correcting for phase-misalignment in the AE sharpened VEP peak responses primarily at low spatial frequencies, but could not account for VEP waveform improvements in the AE after OT at higher spatial frequencies. In summary, VEP abnormalities from the AE are associated with phase-misalignment and reduced SNR possibly related to desynchronization of neuronal activity. The effect of OT on VEP responses is greater than that accounted for by phase-misalignment and SNR alone. Copyright © 2014 Elsevier Ltd. All rights reserved.

Act quickly, decide later: long-latency visual processing underlies perceptual decisions but not reflexive behavior.

PubMed

Jolij, Jacob; Scholte, H Steven; van Gaal, Simon; Hodgson, Timothy L; Lamme, Victor A F

2011-12-01

Humans largely guide their behavior by their visual representation of the world. Recent studies have shown that visual information can trigger behavior within 150 msec, suggesting that visually guided responses to external events, in fact, precede conscious awareness of those events. However, is such a view correct? By using a texture discrimination task, we show that the brain relies on long-latency visual processing in order to guide perceptual decisions. Decreasing stimulus saliency leads to selective changes in long-latency visually evoked potential components reflecting scene segmentation. These latency changes are accompanied by almost equal changes in simple RTs and points of subjective simultaneity. Furthermore, we find a strong correlation between individual RTs and the latencies of scene segmentation related components in the visually evoked potentials, showing that the processes underlying these late brain potentials are critical in triggering a response. However, using the same texture stimuli in an antisaccade task, we found that reflexive, but erroneous, prosaccades, but not antisaccades, can be triggered by earlier visual processes. In other words: The brain can act quickly, but decides late. Differences between our study and earlier findings suggesting that action precedes conscious awareness can be explained by assuming that task demands determine whether a fast and unconscious, or a slower and conscious, representation is used to initiate a visually guided response.

Accommodation and vergence latencies in human infants

PubMed Central

Tondel, Grazyna M.; Candy, T. Rowan

2008-01-01

Purpose Achieving simultaneous single and clear visual experience during postnatal development depends on the temporal relationship between accommodation and vergence, in addition to their accuracies. This study was designed to examine one component of the dynamic relationship, the latencies of the responses. Methods Infants and adults were tested in three conditions i) Binocular viewing of a target moving in depth at 5cm/s (closed loop) ii) monocular viewing of the same target (vergence open loop) iii) binocular viewing of a low spatial frequency Difference of Gaussian target during a prism induced step change in retinal disparity (accommodation open loop). Results There was a significant correlation between accommodation and vergence latencies in binocular conditions for infants from 7 to 23 weeks of age. Some of the infants, as young as 7 or 8 weeks, generated adult-like latencies of less than 0.5 s. Latencies in the vergence open loop and accommodation open loop conditions tended to be shorter for the stimulated system than the open loop system in both cases, and all latencies were typically less than 2 seconds across the infant age range. Conclusions Many infants between 7 and 23 weeks of age were able to generate accommodation and vergence responses with latencies of less than a second in full binocular closed loop conditions. The correlation between the latencies in the two systems suggests that they are limited by related factors from the earliest ages tested. PMID:18199466

Accommodation and vergence latencies in human infants.

PubMed

Tondel, Grazyna M; Candy, T Rowan

2008-02-01

Achieving simultaneous single and clear visual experience during postnatal development depends on the temporal relationship between accommodation and vergence, in addition to their accuracies. This study was designed to examine one component of the dynamic relationship, the latencies of the responses. Infants and adults were tested in three conditions (i) binocular viewing of a target moving in depth at 5 cm/s (closed loop) (ii) monocular viewing of the same target (vergence open loop) (iii) binocular viewing of a low spatial frequency Difference of Gaussian target during a prism induced step change in retinal disparity (accommodation open loop). There was a significant correlation between accommodation and vergence latencies in binocular conditions for infants from 7 to 23 weeks of age. Some of the infants, as young as 7 or 8 weeks, generated adult-like latencies of less than 0.5 s. Latencies in the vergence open loop and accommodation open loop conditions tended to be shorter for the stimulated system than the open loop system in both cases, and all latencies were typically less than 2 s across the infant age range. Many infants between 7 and 23 weeks of age were able to generate accommodation and vergence responses with latencies of less than a second in full binocular closed loop conditions. The correlation between the latencies in the two systems suggests that they are limited by related factors from the earliest ages tested.

State-dependent changes in cortical gain control as measured by auditory evoked responses to varying intensity stimuli.

PubMed

Phillips, Derrick J; Schei, Jennifer L; Meighan, Peter C; Rector, David M

2011-11-01

Auditory evoked potential (AEP) components correspond to sequential activation of brain structures within the auditory pathway and reveal neural activity during sensory processing. To investigate state-dependent modulation of stimulus intensity response profiles within different brain structures, we assessed AEP components across both stimulus intensity and state. We implanted adult female Sprague-Dawley rats (N = 6) with electrodes to measure EEG, EKG, and EMG. Intermittent auditory stimuli (6-12 s) varying from 50 to 75 dBa were delivered over a 24-h period. Data were parsed into 2-s epochs and scored for wake/sleep state. All AEP components increased in amplitude with increased stimulus intensity during wake. During quiet sleep, however, only the early latency response (ELR) showed this relationship, while the middle latency response (MLR) increased at the highest 75 dBa intensity, and the late latency response (LLR) showed no significant change across the stimulus intensities tested. During rapid eye movement sleep (REM), both ELR and LLR increased, similar to wake, but MLR was severely attenuated. Stimulation intensity and the corresponding AEP response profile were dependent on both brain structure and sleep state. Lower brain structures maintained stimulus intensity and neural response relationships during sleep. This relationship was not observed in the cortex, implying state-dependent modification of stimulus intensity coding. Since AEP amplitude is not modulated by stimulus intensity during sleep, differences between paired 75/50 dBa stimuli could be used to determine state better than individual intensities.

Intensive care unit robotic telepresence facilitates rapid physician response to unstable patients and decreased cost in neurointensive care.

PubMed

Vespa, Paul M; Miller, Chad; Hu, Xiao; Nenov, Val; Buxey, Farzad; Martin, Neil A

2007-04-01

The timely assessment and treatment of ICU patients is important for neurosurgeons and neurointensivists. We hypothesized that the use of RTP can improve physician rapid response to unstable ICU patients. This is a prospective study using a before-after, cohort-control design to test the effectiveness of RTP. Physicians used RTP to make rounds in the ICU in response to nursing pages. Data concerning several aspects of the RTP interaction including the latency of the response, the problem being treated, the intervention that was ordered, and the type of information gathered using the RTP were documented. The effect of RTP on ICU length of stay and cost was assessed. The use of RTP was associated with a reduction in latency of attending physician face-to-face response for routine and urgent pages compared to conventional care (RTP: 9.2 +/- 9.3 minutes vs conventional: 218 +/- 186 minutes). The response latencies to brain ischemia (7.8 +/- 2.8 vs 152 +/- 85 minutes) and elevated ICP (11 +/- 14 vs 108 +/- 55 minutes) were reduced (P < .001), as was the LOS for patients with SAH (2 days) and brain trauma (1 day). There was an increase in ICU occupancy by 11% compared with the prerobot era, and there was an ICU cost savings of $1.1 million attributable to the use of RTP. The use of RTP enabled rapid face-to-face attending physician response to ICU patients and resulted in decreased ICU cost and LOS.

Event-Related Potential responses to the acute and chronic effects of alcohol in adolescent and adult Wistar rats

PubMed Central

Ehlers, Cindy L.; Desikan, Anita; Wills, Derek N.

2014-01-01

Background The present study explored the hypothesis that adolescent ethanol exposure may cause long lasting changes in ethanol sensitivity by exploring the age-related effects of acute alcohol on intoxication and on event-related potential (ERP) responses to acoustic stimuli in ethanol naïve adolescent and adult male Wistar rats and in adult rats that were exposed to chronic ethanol/control conditions during adolescence. Methods Ethanol naïve adolescent (postnatal day 32 (PD32)) and adult male rats (PD99) were included in the first study. In a second study, rats were exposed to 5 weeks of ethanol vapor (Blood ethanol concentrations @ 175 mg%) or air from PD24 to PD59 and allowed to mature until PD90. In both studies rats were implanted with cortical recording electrodes, and the effects of acute ethanol (0.0, 1.5, and 3.0 g/kg) on behavioral and ERP responses were assessed. Results Adolescents were found to have higher amplitude and longer latency P3a and P3b components at baseline as compared to adult rats, and ethanol was found to produce a robust dose-dependent increase in the latency of the P3a and P3b components of the auditory ERP recorded in cortical sites in both adolescents and adults. However, ethanol produced significantly larger delays in P3a and P3b latencies in adults as compared to adolescents. Acute ethanol administration was also found to produce a robust dose dependent increase in the latency of the P3a and P3b components in adult animals exposed to ethanol vapor as adolescents and air exposed controls; however, larger acute ethanol-induced increases in P3a and P3b latencies were seen in controls as compared to adolescent vapor exposed rats. Conclusions Adolescent rats have a less intense P3 latency response to acute ethanol administration when compared to adult rats. Exposure to chronic ethanol during adolescence can cause “retention” of the adolescent phenotype of reduced P3 latency sensitivity to ethanol. PMID:24483322

Minimizing Input-to-Output Latency in Virtual Environment

NASA Technical Reports Server (NTRS)

Adelstein, Bernard D.; Ellis, Stephen R.; Hill, Michael I.

2009-01-01

A method and apparatus were developed to minimize latency (time delay ) in virtual environment (VE) and other discrete- time computer-base d systems that require real-time display in response to sensor input s. Latency in such systems is due to the sum of the finite time requi red for information processing and communication within and between sensors, software, and displays.

Reconstructing the calibrated strain signal in the Advanced LIGO detectors

NASA Astrophysics Data System (ADS)

Viets, A. D.; Wade, M.; Urban, A. L.; Kandhasamy, S.; Betzwieser, J.; Brown, Duncan A.; Burguet-Castell, J.; Cahillane, C.; Goetz, E.; Izumi, K.; Karki, S.; Kissel, J. S.; Mendell, G.; Savage, R. L.; Siemens, X.; Tuyenbayev, D.; Weinstein, A. J.

2018-05-01

Advanced LIGO’s raw detector output needs to be calibrated to compute dimensionless strain h(t) . Calibrated strain data is produced in the time domain using both a low-latency, online procedure and a high-latency, offline procedure. The low-latency h(t) data stream is produced in two stages, the first of which is performed on the same computers that operate the detector’s feedback control system. This stage, referred to as the front-end calibration, uses infinite impulse response (IIR) filtering and performs all operations at a 16 384 Hz digital sampling rate. Due to several limitations, this procedure currently introduces certain systematic errors in the calibrated strain data, motivating the second stage of the low-latency procedure, known as the low-latency gstlal calibration pipeline. The gstlal calibration pipeline uses finite impulse response (FIR) filtering to apply corrections to the output of the front-end calibration. It applies time-dependent correction factors to the sensing and actuation components of the calibrated strain to reduce systematic errors. The gstlal calibration pipeline is also used in high latency to recalibrate the data, which is necessary due mainly to online dropouts in the calibrated data and identified improvements to the calibration models or filters.

Fast Coding of Orientation in Primary Visual Cortex

PubMed Central

Shriki, Oren; Kohn, Adam; Shamir, Maoz

2012-01-01

Understanding how populations of neurons encode sensory information is a major goal of systems neuroscience. Attempts to answer this question have focused on responses measured over several hundred milliseconds, a duration much longer than that frequently used by animals to make decisions about the environment. How reliably sensory information is encoded on briefer time scales, and how best to extract this information, is unknown. Although it has been proposed that neuronal response latency provides a major cue for fast decisions in the visual system, this hypothesis has not been tested systematically and in a quantitative manner. Here we use a simple ‘race to threshold’ readout mechanism to quantify the information content of spike time latency of primary visual (V1) cortical cells to stimulus orientation. We find that many V1 cells show pronounced tuning of their spike latency to stimulus orientation and that almost as much information can be extracted from spike latencies as from firing rates measured over much longer durations. To extract this information, stimulus onset must be estimated accurately. We show that the responses of cells with weak tuning of spike latency can provide a reliable onset detector. We find that spike latency information can be pooled from a large neuronal population, provided that the decision threshold is scaled linearly with the population size, yielding a processing time of the order of a few tens of milliseconds. Our results provide a novel mechanism for extracting information from neuronal populations over the very brief time scales in which behavioral judgments must sometimes be made. PMID:22719237

Waveform Similarity Analysis: A Simple Template Comparing Approach for Detecting and Quantifying Noisy Evoked Compound Action Potentials.

PubMed

Potas, Jason Robert; de Castro, Newton Gonçalves; Maddess, Ted; de Souza, Marcio Nogueira

2015-01-01

Experimental electrophysiological assessment of evoked responses from regenerating nerves is challenging due to the typical complex response of events dispersed over various latencies and poor signal-to-noise ratio. Our objective was to automate the detection of compound action potential events and derive their latencies and magnitudes using a simple cross-correlation template comparison approach. For this, we developed an algorithm called Waveform Similarity Analysis. To test the algorithm, challenging signals were generated in vivo by stimulating sural and sciatic nerves, whilst recording evoked potentials at the sciatic nerve and tibialis anterior muscle, respectively, in animals recovering from sciatic nerve transection. Our template for the algorithm was generated based on responses evoked from the intact side. We also simulated noisy signals and examined the output of the Waveform Similarity Analysis algorithm with imperfect templates. Signals were detected and quantified using Waveform Similarity Analysis, which was compared to event detection, latency and magnitude measurements of the same signals performed by a trained observer, a process we called Trained Eye Analysis. The Waveform Similarity Analysis algorithm could successfully detect and quantify simple or complex responses from nerve and muscle compound action potentials of intact or regenerated nerves. Incorrectly specifying the template outperformed Trained Eye Analysis for predicting signal amplitude, but produced consistent latency errors for the simulated signals examined. Compared to the trained eye, Waveform Similarity Analysis is automatic, objective, does not rely on the observer to identify and/or measure peaks, and can detect small clustered events even when signal-to-noise ratio is poor. Waveform Similarity Analysis provides a simple, reliable and convenient approach to quantify latencies and magnitudes of complex waveforms and therefore serves as a useful tool for studying evoked compound action potentials in neural regeneration studies.

Waveform Similarity Analysis: A Simple Template Comparing Approach for Detecting and Quantifying Noisy Evoked Compound Action Potentials

PubMed Central

Potas, Jason Robert; de Castro, Newton Gonçalves; Maddess, Ted; de Souza, Marcio Nogueira

2015-01-01

Experimental electrophysiological assessment of evoked responses from regenerating nerves is challenging due to the typical complex response of events dispersed over various latencies and poor signal-to-noise ratio. Our objective was to automate the detection of compound action potential events and derive their latencies and magnitudes using a simple cross-correlation template comparison approach. For this, we developed an algorithm called Waveform Similarity Analysis. To test the algorithm, challenging signals were generated in vivo by stimulating sural and sciatic nerves, whilst recording evoked potentials at the sciatic nerve and tibialis anterior muscle, respectively, in animals recovering from sciatic nerve transection. Our template for the algorithm was generated based on responses evoked from the intact side. We also simulated noisy signals and examined the output of the Waveform Similarity Analysis algorithm with imperfect templates. Signals were detected and quantified using Waveform Similarity Analysis, which was compared to event detection, latency and magnitude measurements of the same signals performed by a trained observer, a process we called Trained Eye Analysis. The Waveform Similarity Analysis algorithm could successfully detect and quantify simple or complex responses from nerve and muscle compound action potentials of intact or regenerated nerves. Incorrectly specifying the template outperformed Trained Eye Analysis for predicting signal amplitude, but produced consistent latency errors for the simulated signals examined. Compared to the trained eye, Waveform Similarity Analysis is automatic, objective, does not rely on the observer to identify and/or measure peaks, and can detect small clustered events even when signal-to-noise ratio is poor. Waveform Similarity Analysis provides a simple, reliable and convenient approach to quantify latencies and magnitudes of complex waveforms and therefore serves as a useful tool for studying evoked compound action potentials in neural regeneration studies. PMID:26325291

Typing pictures: Linguistic processing cascades into finger movements.

PubMed

Scaltritti, Michele; Arfé, Barbara; Torrance, Mark; Peressotti, Francesca

2016-11-01

The present study investigated the effect of psycholinguistic variables on measures of response latency and mean interkeystroke interval in a typewritten picture naming task, with the aim to outline the functional organization of the stages of cognitive processing and response execution associated with typewritten word production. Onset latencies were modulated by lexical and semantic variables traditionally linked to lexical retrieval, such as word frequency, age of acquisition, and naming agreement. Orthographic variables, both at the lexical and sublexical level, appear to influence just within-word interkeystroke intervals, suggesting that orthographic information may play a relevant role in controlling actual response execution. Lexical-semantic variables also influenced speed of execution. This points towards cascaded flow of activation between stages of lexical access and response execution. Copyright © 2016 Elsevier B.V. All rights reserved.

Molecular analyses of the principal components of response strength.

PubMed Central

Killeen, Peter R; Hall, Scott S; Reilly, Mark P; Kettle, Lauren C

2002-01-01

Killeen and Hall (2001) showed that a common factor called strength underlies the key dependent variables of response probability, latency, and rate, and that overall response rate is a good predictor of strength. In a search for the mechanisms that underlie those correlations, this article shows that (a) the probability of responding on a trial is a two-state Markov process; (b) latency and rate of responding can be described in terms of the probability and period of stochastic machines called clocked Bernoulli modules, and (c) one such machine, the refractory Poisson process, provides a functional relation between the probability of observing a response during any epoch and the rate of responding. This relation is one of proportionality at low rates and curvilinearity at higher rates. PMID:12216975

Does Noise From Shipping and Boat Traffic Affect Predator Vigilance in the European Common Hermit Crab?

PubMed

Nousek-McGregor, Anna E; Mei, Francesca Tee Liang

2016-01-01

The effect of noise on predator vigilance in Pagurus bernhardus was explored in this study. Latency of the first response, emergence time, and response type were measured from hermit crabs during continuous and variable vessel noise and two controls. The mean (±SE) response latency was longer for the noise treatments (continuous, 18.19 ± 2.78 s; variable, 11.39 ± 1.48 s) than for the controls (ambient, 7.21 ± 0.82 s; silent, 6.66 ± 0.95 s). Response type and emergence time were not significantly affected but were more variable during the noise treatments than during the controls. Noisy conditions may increase predation risk, suggesting potential fitness consequences for invertebrates.

Antibody-Independent Control of γ-Herpesvirus Latency via B Cell Induction of Anti-Viral T Cell Responses

PubMed Central

McClellan, Kelly B; Gangappa, Shivaprakash; Speck, Samuel H; Virgin, Herbert W.

2006-01-01

B cells can use antibody-dependent mechanisms to control latent viral infections. It is unknown whether this represents the sole function of B cells during chronic viral infection. We report here that hen egg lysozyme (HEL)-specific B cells can contribute to the control of murine γ-herpesvirus 68 (γHV68) latency without producing anti-viral antibody. HEL-specific B cells normalized defects in T cell numbers and proliferation observed in B cell−/− mice during the early phase of γHV68 latency. HEL-specific B cells also reversed defects in CD8 and CD4 T cell cytokine production observed in B cell−/− mice, generating CD8 and CD4 T cells necessary for control of latency. Furthermore, HEL-specific B cells were able to present virally encoded antigen to CD8 T cells. Therefore, B cells have antibody independent functions, including antigen presentation, that are important for control of γ-herpesvirus latency. Exploitation of this property of B cells may allow enhanced vaccine responses to chronic virus infection. PMID:16789842

Auditory middle latency responses differ in right- and left-handed subjects: an evaluation through topographic brain mapping.

PubMed

Mohebbi, Mehrnaz; Mahmoudian, Saeid; Alborzi, Marzieh Sharifian; Najafi-Koopaie, Mojtaba; Farahani, Ehsan Darestani; Farhadi, Mohammad

2014-09-01

To investigate the association of handedness with auditory middle latency responses (AMLRs) using topographic brain mapping by comparing amplitudes and latencies in frontocentral and hemispheric regions of interest (ROIs). The study included 44 healthy subjects with normal hearing (22 left handed and 22 right handed). AMLRs were recorded from 29 scalp electrodes in response to binaural 4-kHz tone bursts. Frontocentral ROI comparisons revealed that Pa and Pb amplitudes were significantly larger in the left-handed than the right-handed group. Topographic brain maps showed different distributions in AMLR components between the two groups. In hemispheric comparisons, Pa amplitude differed significantly across groups. A left-hemisphere emphasis of Pa was found in the right-handed group but not in the left-handed group. This study provides evidence that handedness is associated with AMLR components in frontocentral and hemispheric ROI. Handedness should be considered an essential factor in the clinical or experimental use of AMLRs.

Typing is writing: Linguistic properties modulate typing execution.

PubMed

Pinet, Svetlana; Ziegler, Johannes C; Alario, F-Xavier

2016-12-01

Typing is becoming our preferred way of writing. Perhaps because of the relative recency of this change, very few studies have investigated typing from a psycholinguistic perspective. In addition, and despite obvious similarities between typing and handwriting, typing research has remained rather disconnected from handwriting research. The current study aimed at bridging this gap by evaluating how typing is affected by a number of psycholinguistic variables defined at the word, syllable, and letter levels. In a writing-to-dictation task, we assessed typing performance by measuring response accuracy, onset latencies - an index of response preparation and initiation - and interkeystroke intervals (IKIs) - an index of response execution processes. The lexical and sublexical factors revealed a composite pattern of effects. Lexical frequency improved response latencies and accuracy, while bigram frequency speeded up IKIs. Sound-spelling consistency improved latencies, but had an inhibitory effect on IKI. IKIs were also longer at syllable boundaries. Together, our findings can be fit within a framework for typed production that combines the previously developed theories of spelling and typing execution. At their interface, we highlight the need for an intermediate hierarchical stage, perhaps in the form of a graphemic buffer for typing.

Simultaneous diffuse near-infrared imaging of hemodynamic and oxygenation changes and electroencephalographic measurements of neuronal activity in the human brain

NASA Astrophysics Data System (ADS)

Noponen, Tommi; Kicic, Dubravko; Kotilahti, Kalle; Kajava, Timo; Kahkonen, Seppo; Nissila, Ilkka; Merilainen, Pekka; Katila, Toivo

2005-04-01

Visually evoked hemodynamic responses and potentials were simultaneously measured using a 16-channel optical imaging instrument and a 60-channel electroencephalography instrument during normo-, hypo- and hypercapnia from three subjects. Flashing and pattern-reversed checkerboard stimuli were used. The study protocol included two counterbalanced measurements during both normo- and hypocapnia and normo- and hypercapnia. Hypocapnia was produced by controlled hyperventilation and hypercapnia by breathing carbon dioxide enriched air. Near-infrared imaging was also used to monitor the concentration changes of oxy- and deoxyhaemoglobin due to hypo- and hypercapnia. Hemodynamic responses and evoked potentials were successfully detected for each subject above the visual cortex. The latencies of the hemodynamic responses during hypocapnia were shorter whereas during hypercapnia they were longer when compared to the latencies during normocapnia. Hypocapnia tended to decrease the latencies of visually evoked potentials compared to those during normocapnia while hypercapnia did not show any consistent effect to the potentials. The developed measurement setup and the study protocol provide the opportunity to investigate the neurovascular coupling and the links between the baseline level of blood flow, electrical activity and hemodynamic responses in the human brain.

Dopamine Modulation of Avoidance Behavior in Caenorhabditis elegans Requires the NMDA Receptor NMR-1

PubMed Central

Baidya, Melvin; Genovez, Marx; Torres, Marissa; Chao, Michael Y.

2014-01-01

The nematode C. elegans utilizes a relatively simple neural circuit to mediate avoidance responses to noxious stimuli such as the volatile odorant octanol. This avoidance behavior is modulated by dopamine. cat-2 mutant animals that are deficient in dopamine biosynthesis have an increased response latency to octanol compared to wild type animals, and this defect can be fully restored with the application of exogenous dopamine. Because this avoidance behavior is mediated by glutamatergic signaling between sensory neurons and premotor interneurons, we investigated the genetic interactions between dopaminergic signaling and ionotropic glutamate receptors. cat-2 mutant animals lacking either the GLR-1 or GLR-2 AMPA/kainate receptors displayed an increased response latency to octanol, which could be restored via exogenous dopamine. However, whereas cat-2 mutant animals lacking the NMR-1 NMDA receptor had increased response latency to octanol they were insensitive to exogenous dopamine. Mutants that lacked both AMPA/kainate and NMDA receptors were also insensitive to exogenous dopamine. Our results indicate that dopamine modulation of octanol avoidance requires NMR-1, consistent with NMR-1 as a potential downstream signaling target for dopamine. PMID:25089710

Effects of age on cognitive control during semantic categorization.

PubMed

Mudar, Raksha A; Chiang, Hsueh-Sheng; Maguire, Mandy J; Spence, Jeffrey S; Eroh, Justin; Kraut, Michael A; Hart, John

2015-01-01

We used event-related potentials (ERPs) to study age effects of perceptual (basic-level) vs. perceptual-semantic (superordinate-level) categorization on cognitive control using the go/nogo paradigm. Twenty-two younger (11 M; 21 ± 2.2 years) and 22 older adults (9 M; 63 ± 5.8 years) completed two visual go/nogo tasks. In the single-car task (SiC) (basic), go/nogo responses were made based on single exemplars of a car (go) and a dog (nogo). In the object animal task (ObA) (superordinate), responses were based on multiple exemplars of objects (go) and animals (nogo). Each task consisted of 200 trials: 160 (80%) 'go' trials that required a response through button pressing and 40 (20%) 'nogo' trials that required inhibition/withholding of a response. ERP data revealed significantly reduced nogo-N2 and nogo-P3 amplitudes in older compared to younger adults, whereas go-N2 and go-P3 amplitudes were comparable in both groups during both categorization tasks. Although the effects of categorization levels on behavioral data and P3 measures were similar in both groups with longer response times, lower accuracy scores, longer P3 latencies, and lower P3 amplitudes in ObA compared to SiC, N2 latency revealed age group differences moderated by the task. Older adults had longer N2 latency for ObA compared to SiC, in contrast, younger adults showed no N2 latency difference between SiC and ObA. Overall, these findings suggest that age differentially affects neural processing related to cognitive control during semantic categorization. Furthermore, in older adults, unlike in younger adults, levels of categorization modulate neural processing related to cognitive control even at the early stages (N2). Published by Elsevier B.V.

Trial latencies estimation of event-related potentials in EEG by means of genetic algorithms

NASA Astrophysics Data System (ADS)

Da Pelo, P.; De Tommaso, M.; Monaco, A.; Stramaglia, S.; Bellotti, R.; Tangaro, S.

2018-04-01

Objective. Event-related potentials (ERPs) are usually obtained by averaging thus neglecting the trial-to-trial latency variability in cognitive electroencephalography (EEG) responses. As a consequence the shape and the peak amplitude of the averaged ERP are smeared and reduced, respectively, when the single-trial latencies show a relevant variability. To date, the majority of the methodologies for single-trial latencies inference are iterative schemes providing suboptimal solutions, the most commonly used being the Woody’s algorithm. Approach. In this study, a global approach is developed by introducing a fitness function whose global maximum corresponds to the set of latencies which renders the trial signals most aligned as possible. A suitable genetic algorithm has been implemented to solve the optimization problem, characterized by new genetic operators tailored to the present problem. Main results. The results, on simulated trials, showed that the proposed algorithm performs better than Woody’s algorithm in all conditions, at the cost of an increased computational complexity (justified by the improved quality of the solution). Application of the proposed approach on real data trials, resulted in an increased correlation between latencies and reaction times w.r.t. the output from RIDE method. Significance. The above mentioned results on simulated and real data indicate that the proposed method, providing a better estimate of single-trial latencies, will open the way to more accurate study of neural responses as well as to the issue of relating the variability of latencies to the proper cognitive and behavioural correlates.

Epidemiology of Vestibular Evoked Myogenic Potentials: Data from the Baltimore Longitudinal Study of Aging

PubMed Central

Li, Carol; Layman, Andrew J.; Carey, John; Agrawal, Yuri

2015-01-01

Objective To evaluate whether age-related changes in vestibular evoked myogenic potentials (VEMPs) differ by demographic and cardiovascular risk groups. Methods Participants in the Baltimore Longitudinal Study of Aging underwent cervical and ocular VEMP testing. VEMP latency, amplitude, asymmetry ratios, and prevalence of absent responses were compared across demographic and cardiovascular risk groups. Results In 257 participants (mean age 72.9, 57% female), ocular VEMP (oVEMP) n10 latency increased by 0.12 ms/decade while amplitude decreased by 2.9 μV/decade. Black participants had better oVEMP function (shorter latency, increased amplitude, and decreased odds of absent responses) relative to white participants. In 250 participants (mean age 72.6, 54% female), EMG-corrected cervical VEMP (cVEMP) amplitude decreased by 0.14 μV /decade and p13 latency was 0.38 ms longer in males. The odds of absent responses were significantly higher in individuals age ≥ 80 for oVEMPs, and age ≥ 70 for cVEMPs. Cardiovascular risk factors had no association with VEMP parameters. Conclusions We confirmed age-related declines in otolith function, and observed a protective effect of black race on oVEMP latency and amplitude. Significance These results illustrate how measures of otolith function change with age in community-dwelling adults. Further investigations are needed to ascertain whether better otolith function in blacks might contribute to a lower risk of mobility disability and falls. PMID:25703943

Simian Varicella Virus Infection of Rhesus Macaques Recapitulates Essential Features of Varicella Zoster Virus Infection in Humans

PubMed Central

Messaoudi, Ilhem; Barron, Alexander; Wellish, Mary; Engelmann, Flora; Legasse, Alfred; Planer, Shannon; Gilden, Don; Nikolich-Zugich, Janko; Mahalingam, Ravi

2009-01-01

Simian varicella virus (SVV), the etiologic agent of naturally occurring varicella in primates, is genetically and antigenically closely related to human varicella zoster virus (VZV). Early attempts to develop a model of VZV pathogenesis and latency in nonhuman primates (NHP) resulted in persistent infection. More recent models successfully produced latency; however, only a minority of monkeys became viremic and seroconverted. Thus, previous NHP models were not ideally suited to analyze the immune response to SVV during acute infection and the transition to latency. Here, we show for the first time that intrabronchial inoculation of rhesus macaques with SVV closely mimics naturally occurring varicella (chickenpox) in humans. Infected monkeys developed varicella and viremia that resolved 21 days after infection. Months later, viral DNA was detected only in ganglia and not in non-ganglionic tissues. Like VZV latency in human ganglia, transcripts corresponding to SVV ORFs 21, 62, 63 and 66, but not ORF 40, were detected by RT-PCR. In addition, as described for VZV, SVV ORF 63 protein was detected in the cytoplasm of neurons in latently infected monkey ganglia by immunohistochemistry. We also present the first in depth analysis of the immune response to SVV. Infected animals produced a strong humoral and cell-mediated immune response to SVV, as assessed by immunohistology, serology and flow cytometry. Intrabronchial inoculation of rhesus macaques with SVV provides a novel model to analyze viral and immunological mechanisms of VZV latency and reactivation. PMID:19911054

Simian varicella virus infection of rhesus macaques recapitulates essential features of varicella zoster virus infection in humans.

PubMed

Messaoudi, Ilhem; Barron, Alexander; Wellish, Mary; Engelmann, Flora; Legasse, Alfred; Planer, Shannon; Gilden, Don; Nikolich-Zugich, Janko; Mahalingam, Ravi

2009-11-01

Simian varicella virus (SVV), the etiologic agent of naturally occurring varicella in primates, is genetically and antigenically closely related to human varicella zoster virus (VZV). Early attempts to develop a model of VZV pathogenesis and latency in nonhuman primates (NHP) resulted in persistent infection. More recent models successfully produced latency; however, only a minority of monkeys became viremic and seroconverted. Thus, previous NHP models were not ideally suited to analyze the immune response to SVV during acute infection and the transition to latency. Here, we show for the first time that intrabronchial inoculation of rhesus macaques with SVV closely mimics naturally occurring varicella (chickenpox) in humans. Infected monkeys developed varicella and viremia that resolved 21 days after infection. Months later, viral DNA was detected only in ganglia and not in non-ganglionic tissues. Like VZV latency in human ganglia, transcripts corresponding to SVV ORFs 21, 62, 63 and 66, but not ORF 40, were detected by RT-PCR. In addition, as described for VZV, SVV ORF 63 protein was detected in the cytoplasm of neurons in latently infected monkey ganglia by immunohistochemistry. We also present the first in depth analysis of the immune response to SVV. Infected animals produced a strong humoral and cell-mediated immune response to SVV, as assessed by immunohistology, serology and flow cytometry. Intrabronchial inoculation of rhesus macaques with SVV provides a novel model to analyze viral and immunological mechanisms of VZV latency and reactivation.

Auditory middle latency response in children with learning difficulties.

PubMed

Frizzo, Ana Claudia Figueiredo; Issac, Myriam Lima; Pontes-Fernandes, Angela Cristina; Menezes, Pedro de Lemos; Funayama, Carolina Araújo Rodrigues

2012-07-01

 This is an objective laboratory assessment of the central auditory systems of children with learning disabilities.  To examine and determine the properties of the components of the Auditory Middle Latency Response in a sample of children with learning disabilities.  This was a prospective, cross-sectional cohort study with quantitative, descriptive, and exploratory outcomes. We included 50 children aged 8-13 years of both genders with and without learning disorders. Those with disorders of known organic, environmental, or genetic causes were excluded.  The Na, Pa, and Nb waves were identified in all subjects. The ranges of the latency component values were as follows: Na = 9.8-32.3 ms, Pa = 19.0-51.4 ms, Nb = 30.0-64.3 ms (learning disorders group) and Na = 13.2-29.6 ms, Pa = 21.8-42.8 ms, Nb = 28.4-65.8 ms (healthy group). The values of the Na-Pa amplitude ranged from 0.3 to 6.8 ìV (learning disorders group) or 0.2-3.6 ìV (learning disorders group). Upon analysis, the functional characteristics of the groups were distinct: the left hemisphere Nb latency was longer in the study group than in the control group. Peculiarities of the electrophysiological measures were observed in the children with learning disorders. This study has provided information on the Auditory Middle Latency Response and can serve as a reference for other clinical and experimental studies in children with these disorders.

Fetal auditory evoked responses to onset of amplitude modulated sounds. A fetal magnetoencephalography (fMEG) study.

PubMed

Draganova, R; Schollbach, A; Schleger, F; Braendle, J; Brucker, S; Abele, H; Kagan, K O; Wallwiener, D; Fritsche, A; Eswaran, H; Preissl, H

2018-06-01

The human fetal auditory system is functional around the 25th week of gestational age when the thalamocortical connections are established. Fetal magnetoencephalography (fMEG) provides evidence for fetal auditory brain responses to pure tones and syllables. Fifty-five pregnant women between 31 and 40 weeks of gestation were included in the study. Fetal MEG was recorded during the presentation of an amplitude modulated tone (AM) with a carrier frequency of 500 Hz to the maternal abdomen modulated by low modulation rates (MRs) - 2/s and 4/s, middle MR - 8/s and high MRs - 27/s, 42/s, 78/s and 91/s. The aim was to determine whether the fetal brain responds differently to envelope slopes and intensity change at the onset of the AM sounds. A significant decrease of the response latencies of transient event-related responses (ERR) to high and middle MRs in comparison to the low MRs was observed. The highest fetal response rate was achieved by modulation rates of 2/s, 4/s and 27/s (70%, 57%, and 86%, respectively). Additionally, a maturation effect of the ERR (response latency vs. gestational age) was observed only for 4/s MR. The significant difference between the response latencies to low, middle, and high MRs suggests that still before birth the fetal brain processes the sound slopes at the onset in different integration time-windows, depending on the time for the intensity increase or stimulus power density at the onset, which is a prerequisite for language acquisition. Copyright © 2018 Elsevier B.V. All rights reserved.

Studies Related to Computer-Assisted Instruction. Semi-Annual Progress Report on Contract Nonr-624(18) October 1, 1968 through March 31, 1969.

ERIC Educational Resources Information Center

Glaser, Robert

A study of response latency in a drill-and-practice task showed that variability in latency measures could be reduced by the use of self-pacing procedures, but not by the detailed analysis of latency into separate components. Experiments carried out on instructional history variables in teaching a mirror image, oblique line discrimination, showed…

A centre for accommodative vergence motor control

NASA Technical Reports Server (NTRS)

Wilson, D.

1973-01-01

Latencies in accommodation, accommodative-vergence, and pupil-diameter responses to changing accommodation stimuli, as well as latencies in pupil response to light-intensity changes were measured. From the information obtained, a block diagram has been derived that uses the least number of blocks for representing the accommodation, accommodative-vergence, and pupil systems. The signal transmission delays over the various circuits of the model have been determined and compared to known experimental physiological-delay data. The results suggest the existence of a motor center that controls the accommodative vergence and is completely independent of the accommodation system.

The Influence of Verb-Bound Syntactic Preferences on the Processing of Syntactic Structures

ERIC Educational Resources Information Center

Segaert, Katrien; Weber, Kirsten; Cladder-Micus, Mira; Hagoort, Peter

2014-01-01

Speakers sometimes repeat syntactic structures across sentences, a phenomenon called syntactic priming. We investigated the influence of verb-bound syntactic preferences on syntactic priming effects in response choices and response latencies for German ditransitive sentences. In the response choices we found "inverse preference effects":…

Distinctive Effect of Donepezil Treatment on P300 and N200 Subcomponents of Auditory Event-Related Evoked Potentials in Alzheimer Disease Patients.

PubMed

Vaitkevičius, Arūnas; Kaubrys, Gintaras; Audronytė, Eglė

2015-07-03

Latency of P300 subcomponent of event-related potentials (ERPs) increases in Alzheimer disease (AD) patients, which correlate well with cognitive impairment. Cholinesterase inhibitors (ChEIs) reduce P300 latency in AD patients with parallel improvement in cognition. It is not known whether N200 response to ChEIs is similar to that of P300. The aim of this study was to evaluate and compare characteristics of P300 and N200 in AD patients, treatment-naïve and on stable donepezil treatment, matched by age, education, sex, and cognitive function. We recruited 22 consecutive treatment-naïve AD patients (AD-N group), 22 AD patients treated with a stable donepezil dose of 10 mg/day for at least 3 months (AD-T group), and 50 healthy controls were recruited. Neuropsychological testing (MMSE, ADAS-Cog, and additional tests) and ERP recording was performed and analyzed. All groups did not differ according to age, duration of education, or sex (p>0.05). AD-N and AD-T groups did not differ according to cognitive function. The AD-T group had longer duration of disease than the AD-N group (p<0.001). The AD-T and AD-N groups did not differ in P300 latencies (p=0.49). N200 latency was longer in the AD-T group (p<0.001). The general linear model showed that significant predictors of P300 latency were age (p=0.019) and AD treatment status (p<0.001). Duration of AD was a significant predictor of N200 latency (p=0.004). The response of N200 latency to donepezil treatment differs from the response of P300. P300 is a better marker of ChEI treatment-dependent cognitive functions. N200 is more dependent on the duration of AD.

Canine Sense and Sensibility: Tipping Points and Response Latency Variability as an Optimism Index in a Canine Judgement Bias Assessment

PubMed Central

Starling, Melissa J.; Branson, Nicholas; Cody, Denis; Starling, Timothy R.; McGreevy, Paul D.

2014-01-01

Recent advances in animal welfare science used judgement bias, a type of cognitive bias, as a means to objectively measure an animal's affective state. It is postulated that animals showing heightened expectation of positive outcomes may be categorised optimistic, while those showing heightened expectations of negative outcomes may be considered pessimistic. This study pioneers the use of a portable, automated apparatus to train and test the judgement bias of dogs. Dogs were trained in a discrimination task in which they learned to touch a target after a tone associated with a lactose-free milk reward and abstain from touching the target after a tone associated with water. Their judgement bias was then probed by presenting tones between those learned in the discrimination task and measuring their latency to respond by touching the target. A Cox's Proportional Hazards model was used to analyse censored response latency data. Dog and Cue both had a highly significant effect on latency and risk of touching a target. This indicates that judgement bias both exists in dogs and differs between dogs. Test number also had a significant effect, indicating that dogs were less likely to touch the target over successive tests. Detailed examination of the response latencies revealed tipping points where average latency increased by 100% or more, giving an indication of where dogs began to treat ambiguous cues as predicting more negative outcomes than positive ones. Variability scores were calculated to provide an index of optimism using average latency and standard deviation at cues after the tipping point. The use of a mathematical approach to assessing judgement bias data in animal studies offers a more detailed interpretation than traditional statistical analyses. This study provides proof of concept for the use of an automated apparatus for measuring cognitive bias in dogs. PMID:25229458

Synaptic delay in the heart: an ionophoretic study.

PubMed Central

Hill-Smith, I; Purves, R D

1978-01-01

1. Neurotransmitters were applied ionophoretically to spontaneously beating clusters of ventricular muscle cells cultured from neonatal rats. 2. Acetylcholine or its analogue carbachol produced hyperpolarization and decreased the rate of spontaneous beating. These responses had minimum latencies of about 250 msec and total durations of 6-12 sec. 3. Noradrenaline, adrenaline or isoprenaline increased the rate of spontaneous beating. The minimum latency for this effect was 3-6 sec. Following a single brief pulse the rate remained elevated for 2 min or more. 4. Chronotropic responses of intact atria from adult rats to stimulation of the autonomic nerves were of similar time course to responses of the cultured muscle cells. 5. Calculations based on the theory of diffusion showed that access of drugs to their receptors could not be rate-limiting for the observed responses, unless a diffusion barrier of rather special properties was postulated. A number of other explanations for the long latencies have been ruled out; these are most likely to be due to some physical or chemical process occurring in or under the cell membrane. 6. Attempts to mimic responses to catecholamines by intracellular application of cyclic AMP were unsuccessful, perhaps because the release of nucleotide from the pipettes was insufficient. A theoretical treatment suggests that ionophoretic efflux of anions might be greatly diminished by the opposing electro-osmotic flux. PMID:209176

Amplitude and timing of somatosensory cortex activity in Task Specific Focal Hand Dystonia

PubMed Central

Dolberg, Rebecca; Hinkley, Leighton B. N.; Honma, Susanne; Zhu, Zhao; Findlay, Anne M.; Byl, Nancy N.; Nagarjan, Srikantan S.

2011-01-01

Objective Task-specific focal hand dystonia (tspFHD) is a movement disorder diagnosed in individuals performing repetitive hand behaviors. The extent to which processing anomalies in primary sensory cortex extend to other regions or across the two hemispheres is presently unclear. Methods In response to low/high rate and novel tactile stimuli on the affected and unaffected hands, magnetoencephalography (MEG) was used to elaborate activity timing and amplitude in the primary somatosensory (S1) and secondary somatosensory/parietal ventral (S2/PV) cortices. MEG and clinical performance measures were collected from thirteen patients and matched controls. Results Compared to controls, subjects with tspFHD had increased response amplitude in S2/PV bilaterally in response to high rate and novel stimuli. Subjects with tspFHD also showed increased response latency (low rate, novel) of the affected digits in contralateral S1. For high rate, subjects with tspFHD showed increased response latency in ipsilateral S1 and S2/PV bilaterally. Activation differences correlated with functional sensory deficits (predicting a latency shift in S1), motor speed and muscle strength. Conclusions There are objective differences in the amplitude and timing of activity for both hands across contralateral and ipsilateral somatosensory cortex in patients with tspFHD. Significance Knowledge of cortical processing abnormalities across S1 and S2/PV in dystonia should be applied towards the development of learning based sensorimotor interventions. PMID:21802357

Auditory cortical responses in patients with cochlear implants

PubMed Central

Burdo, S; Razza, S; Di Berardino, F; Tognola, G

2006-01-01

Summary Currently, the most commonly used electrophysiological tests for cochlear implant evaluation are Averaged Electrical Voltages (AEV), Electrical Advisory Brainstem Responses (EABR) and Neural Response Telemetry (NRT). The present paper focuses on the study of acoustic auditory cortical responses, or slow vertex responses, which are not widely used due to the difficulty in recording, especially in young children. Aims of this study were validation of slow vertex responses and their possible applications in monitoring postimplant results, particularly restoration of hearing and auditory maturation. In practice, the use of tone-bursts, also through hearing aids or cochlear implants, as in slow vertex responses, allows many more frequencies to be investigated and louder intensities to be reached than with other tests based on a click as stimulus. Study design focused on latencies of N1 and P2 slow vertex response peaks in cochlear implants. The study population comprised 45 implant recipients (aged 2 to 70 years), divided into 5 different homogeneous groups according to chronological age, age at onset of deafness, and age at implantation. For each subject, slow vertex responses and free-field auditory responses (PTAS) were recorded for tone-bursts at 500 and 2000 Hz before cochlear implant surgery (using hearing aid amplification) and during scheduled sessions at 3rd and 12th month after implant activation. Results showed that N1 and P2 latencies decreased in all groups starting from 3rd through 12th month after activation. Subjects implanted before school age or at least before age 8 yrs showed the widest latency changes. All subjects showed a reduction in the gap between subjective thresholds (obtained with free field auditory responses) and objective thresholds (obtained with slow vertex responses), obtained in presurgery stage and after cochlear implant. In conclusion, a natural evolution of neurophysiological cortical activities of the auditory pathway, over time, was found especially in young children with prelingual deafness and implanted in preschool age. Cochlear implantation appears to provide hearing restoration, demonstrated by the sharp reduction of the gap between subjective free field auditory responses and slow vertex responses threshold obtained with hearing aids vs. cochlear implant. PMID:16886849

Do Young and Old Preschoolers Exhibit Response Bias Due to Different Mechanisms? Investigating Children's Response Time

ERIC Educational Resources Information Center

Okanda, Mako; Itakura, Shoji

2011-01-01

Previous studies have suggested that younger preschoolers exhibit a yes bias due to underdeveloped cognitive abilities, whereas older preschoolers exhibit a response bias due to other factors. To test this hypothesis, we investigated the response latency to yes-no questions pertaining to familiar and unfamiliar objects in 3- to 6-year-olds. The…

The Role of Predictability in Saccadic Eye Responses in the Suppression Head Impulse Test of Horizontal Semicircular Canal Function.

PubMed

Rey-Martinez, Jorge; Yanes, Joaquin; Esteban, Jonathan; Sanz, Ricardo; Martin-Sanz, Eduardo

2017-01-01

In the suppression head impulse paradigm (SHIMP) vHIT protocol, the participant is instructed to follow with his gaze a mobile target generated by a laser placed on the participant's head. Recent studies have reported that the refixation saccade latencies are in relation with the time evolution of the vestibular dysfunction in both (standard and SHIMP) procedures. We hypothesized that some central mechanisms like head impulse prediction could be one of the causes for the differences in the saccadic eye responses. A prospective cohort non-randomized study was designed. For the SHIMP protocol, recorded with the ICS Impulse ver. 4.0 ® (Otometrics A/S, Taastrup, Denmark) vHIT device, three different algorithms were performed: "predictable," "less predictable," and "unpredictable" depending on the target's predictability. A mathematical method was developed to analyze the SHIMP responses. The method was implemented as an additional tool to the MATLAB open source script for the extended analysis of the vHIT responses named HITCal. In cohort 1, 52 participants were included in "predictable" SHIMP protocol. In cohort 2, 60 patients were included for the "less predictable" and 35 patients for the "unpredictable" SHIMP protocol. The participants made more early saccades when instructed to perform the "predictable" paradigm compared with the "less predictable" paradigm ( p  < 0.001). The less predictable protocol did not reveal any significant difference when compared with the unpredictable protocol ( p  = 0.189). For the latency of the first saccade, there was statistical difference between the "unpredictable" and "predictable" protocols ( p  < 0.001) and between the "less predictable" and "predictable" protocols ( p  < 0.001). Finally, we did not find any relationship between the horizontal vestibulo-ocular reflex (hVOR) gain and the latency of the saccades. We developed a specific method to analyze and detect early SHIMP saccades. Our findings offer evidence regarding the influence of predictability on the latency of the SHIMP saccadic responses, suggesting that early saccades are probably caused by a conditioned response of the participant. The lack of relationship between the hVOR gain and the latency of the saccades suggests that the predictive behavior that caused the early eye saccades are independent of the vestibular function.

Exercise potentiation of lung injury following inhalation of a pneumoedematogenic gas: perfluoroisobutylene.

PubMed

Lehnert, B E; Archuleta, D; Gurley, L R; Session, W; Behr, M J; Lehnert, N M; Stavert, D M

1995-01-01

Exercise performed after exposure to various pneumoedematogenic gases can increase the severity of pulmonary edema beyond that which occurs when exposure is followed by rest. The present study was performed to investigate the potential relationship between a preexisting breach in the lung's permeability status following exposure to an edematogenic gas (perfluoroisobutylene, PFIB) and the potentiating effects of postexposure exercise. Rats were exposed to a concentration of PFIB (100 mg/M3 for 10 min) that results in a unique postexposure latency period (approximately 8 h) prior to the occurrence of overt pulmonary edema. The study examined how exercise performed during and after the latency period affects the severity of the injurious response to this toxic gas. The initial results indicated that exercise performed during the post-PFIB exposure latency period does not potentiate the injurious response, as judged by conventional lung gravimetric and histopathological criteria, but when overt pulmonary edema was preexistent, exercise had a potentiating effect. Changes in lavageable protein were assessed as a more sensitive indicator of permeability changes that may occur during the latency period following PFIB exposure, and the study examined how exercise performed early during the latency period affects this index of pulmonary edema. The study also assessed whether PFIB-induced damage to lung cells is enhanced by exercise during the latency period by measuring lavageable lactate dehydrogenase activity. The results from these latter experiments suggest that a preexisting enhancement in lung permeability is not an absolute requirement for exercise to potentiate the pulmonary edematous response in lungs that are undergoing insidious injury, and that postexposure exercise does not enhance the cell-killing effects of PFIB as a mechanism underlying the exercise potentiating response. Conceivably, the ability of exercise to increase lavageable protein in the absence of a preexisting increase in lung permeability may be due to hyperventilation- and/or pulmonary hypertension-associated intercellular junctional changes that may occur during exercise. Additionally, it remains possible that exercise during PFIB-induced insideous lung injury results in an enhancement in the rate of transcellular transport of blood proteins onto the alveolar surface.

A Bayesian Approach to Estimating Coupling Between Neural Components: Evaluation of the Multiple Component, Event-Related Potential (mcERP) Algorithm

NASA Technical Reports Server (NTRS)

Shah, Ankoor S.; Knuth, Kevin H.; Truccolo, Wilson A.; Ding, Ming-Zhou; Bressler, Steven L.; Schroeder, Charles E.; Clancy, Daniel (Technical Monitor)

2002-01-01

Accurate measurement of single-trial responses is key to a definitive use of complex electromagnetic and hemodynamic measurements in the investigation of brain dynamics. We developed the multiple component, Event-Related Potential (mcERP) approach to single-trial response estimation. To improve our resolution of dynamic interactions between neuronal ensembles located in different layers within a cortical region and/or in different cortical regions. The mcERP model assets that multiple components defined as stereotypic waveforms comprise the stimulus-evoked response and that these components may vary in amplitude and latency from trial to trial. Maximum a posteriori (MAP) solutions for the model are obtained by iterating a set of equations derived from the posterior probability. Our first goal was to use the ANTWERP algorithm to analyze interactions (specifically latency and amplitude correlation) between responses in different layers within a cortical region. Thus, we evaluated the model by applying the algorithm to synthetic data containing two correlated local components and one independent far-field component. Three cases were considered: the local components were correlated by an interaction in their single-trial amplitudes, by an interaction in their single-trial latencies, or by an interaction in both amplitude and latency. We then analyzed the accuracy with which the algorithm estimated the component waveshapes and the single-trial parameters as a function of the linearity of each of these relationships. Extensions of these analyses to real data are discussed as well as ongoing work to incorporate more detailed prior information.

Auditory responses to electric and infrared neural stimulation of the rat cochlear nucleus.

PubMed

Verma, Rohit U; Guex, Amélie A; Hancock, Kenneth E; Durakovic, Nedim; McKay, Colette M; Slama, Michaël C C; Brown, M Christian; Lee, Daniel J

2014-04-01

In an effort to improve the auditory brainstem implant, a prosthesis in which user outcomes are modest, we applied electric and infrared neural stimulation (INS) to the cochlear nucleus in a rat animal model. Electric stimulation evoked regions of neural activation in the inferior colliculus and short-latency, multipeaked auditory brainstem responses (ABRs). Pulsed INS, delivered to the surface of the cochlear nucleus via an optical fiber, evoked broad neural activation in the inferior colliculus. Strongest responses were recorded when the fiber was placed at lateral positions on the cochlear nucleus, close to the temporal bone. INS-evoked ABRs were multipeaked but longer in latency than those for electric stimulation; they resembled the responses to acoustic stimulation. After deafening, responses to electric stimulation persisted, whereas those to INS disappeared, consistent with a reported "optophonic" effect, a laser-induced acoustic artifact. Thus, for deaf individuals who use the auditory brainstem implant, INS alone did not appear promising as a new approach. Copyright © 2014 Elsevier B.V. All rights reserved.

Auditory Responses to Electric and Infrared Neural Stimulation of the Rat Cochlear Nucleus

PubMed Central

Verma, Rohit; Guex, Amelie A.; Hancock, Kenneth E.; Durakovic, Nedim; McKay, Colette M.; Slama, Michaël C. C.; Brown, M. Christian; Lee, Daniel J.

2014-01-01

In an effort to improve the auditory brainstem implant, a prosthesis in which user outcomes are modest, we applied electric and infrared neural stimulation (INS) to the cochlear nucleus in a rat animal model. Electric stimulation evoked regions of neural activation in the inferior colliculus and short-latency, multipeaked auditory brainstem responses (ABRs). Pulsed INS, delivered to the surface of the cochlear nucleus via an optical fiber, evoked broad neural activation in the inferior colliculus. Strongest responses were recorded when the fiber was placed at lateral positions on the cochlear nucleus, close to the temporal bone. INS-evoked ABRs were multipeaked but longer in latency than those for electric stimulation; they resembled the responses to acoustic stimulation. After deafening, responses to electric stimulation persisted, whereas those to INS disappeared, consistent with a reported “optophonic” effect, a laser-induced acoustic artifact. Thus, for deaf individuals who use the auditory brainstem implant, INS alone did not appear promising as a new approach. PMID:24508368

Auditory Brainstem Responses in Young Adults with Down Syndrome.

ERIC Educational Resources Information Center

Widen, Judith E.; And Others

1987-01-01

In a study of 15 individuals (ages 15-21) with Down Syndrome, auditory brainstem response (ABR) detection levels were elevated, response amplitude reduced, and latency-intensity functions were significantly steeper than for a matched control group. Findings were associated with an impairment in hearing sensitivity at 8000 Hz for the experimental…

Lateral step initiation behavior in older adults.

PubMed

Sparto, Patrick J; Jennings, J Richard; Furman, Joseph M; Redfern, Mark S

2014-02-01

Older adults have varied postural responses during induced and voluntary lateral stepping. The purpose of the research was to quantify the occurrence of different stepping strategies during lateral step initiation in older adults and to relate the stepping responses to retrospective history of falls. Seventy community-ambulating older adults (mean age 76 y, range 70-94 y) performed voluntary lateral steps as quickly as possible to the right or left in response to a visual cue, in a blocked design. Vertical ground reaction forces were measured using a forceplate, and the number and latency of postural adjustments were quantified. Subjects were assigned to groups based on their stepping strategy. The frequency of trials with one or two postural adjustments was compared with data from 20 younger adults (mean age 38 y, range 21-58 y). Logistic regression was used to relate presence of a fall in the previous year with the number and latency of postural adjustments. In comparison with younger adults, who almost always demonstrated one postural adjustment when stepping laterally, older adults constituted a continuous distribution in the percentage of step trials made with one postural adjustment (from 0% to 100% of trials). Latencies of the initial postural adjustment and foot liftoff varied depending on the number of postural adjustments made. A history of falls was associated a larger percentage of two postural adjustments, and a longer latency of foot liftoff. In conclusion, the number and latency of postural adjustments made during voluntary lateral stepping provides additional evidence that lateral control of posture may be a critical indicator of aging. Copyright © 2013 Elsevier B.V. All rights reserved.

Idiopathic hypersomnia: a study of 77 cases.

PubMed

Anderson, Kirstie N; Pilsworth, Samantha; Sharples, Linda D; Smith, Ian E; Shneerson, John M

2007-10-01

To review the clinical and polysomnographic characteristics of idiopathic hypersomnia as well as the long-term response to treatment. The Respiratory Support and Sleep Centre at Papworth Hospital, Cambridge, UK. A large database of more than 6000 patients with sleep disorders was reviewed. A retrospective study of the clinical and polysomnographic characteristics of 77 patients with idiopathic hypersomnia was performed. Comparison with a similar group of patients with narcolepsy was performed. The response to drug treatment was assessed in 61 patients over a mean follow-up of 3.8 years. Idiopathic hypersomnia was 60% as prevalent as narcolepsy. Comparison with a similar group of patients with narcolepsy showed that those with idiopathic hypersomnia were more likely to have prolonged unrefreshing daytime naps, a positive family history, increased slow-wave sleep, and a longer sleep latency on the Multiple Sleep Latency Test. The results of the Multiple Sleep Latency Test were not helpful in predicting disease severity or treatment response. The clinical features were heterogeneous and of variable severity. The majority of patients with idiopathic hypersomnia had symptoms that remained stable over many years, but 11% had spontaneous remission, which was never seen in narcolepsy. Two thirds of patients with idiopathic hypersomnolence had a sustained improvement in daytime somnolence with medication, although a third needed high doses or combinations of drugs. Idiopathic hypersomnolence has characteristic clinical and polysomnographic features but the prolonged latency on the Multiple Sleep Latency Test raises doubt about the validity of this test within the current diagnostic criteria. The disease often responds well to treatment and a substantial minority of patients appear to spontaneously improve.

Auditory middle latency response in children with learning difficulties

PubMed Central

Frizzo, Ana Claudia Figueiredo; Issac, Myriam Lima; Pontes-Fernandes, Angela Cristina; Menezes, Pedro de Lemos; Funayama, Carolina Araújo Rodrigues

2012-01-01

Summary Introduction: This is an objective laboratory assessment of the central auditory systems of children with learning disabilities. Aim: To examine and determine the properties of the components of the Auditory Middle Latency Response in a sample of children with learning disabilities. Methods: This was a prospective, cross-sectional cohort study with quantitative, descriptive, and exploratory outcomes. We included 50 children aged 8–13 years of both genders with and without learning disorders. Those with disorders of known organic, environmental, or genetic causes were excluded. Results and Conclusions: The Na, Pa, and Nb waves were identified in all subjects. The ranges of the latency component values were as follows: Na = 9.8–32.3 ms, Pa = 19.0–51.4 ms, Nb = 30.0–64.3 ms (learning disorders group) and Na = 13.2–29.6 ms, Pa = 21.8–42.8 ms, Nb = 28.4–65.8 ms (healthy group). The values of the Na-Pa amplitude ranged from 0.3 to 6.8 ìV (learning disorders group) or 0.2–3.6 ìV (learning disorders group). Upon analysis, the functional characteristics of the groups were distinct: the left hemisphere Nb latency was longer in the study group than in the control group. Peculiarities of the electrophysiological measures were observed in the children with learning disorders. This study has provided information on the Auditory Middle Latency Response and can serve as a reference for other clinical and experimental studies in children with these disorders. PMID:25991954

Lateral step initiation behavior in older adults

PubMed Central

Sparto, Patrick J; Jennings, J Richard; Furman, Joseph M; Redfern, Mark S

2013-01-01

Older adults have varied postural responses during induced and voluntary lateral stepping. The purpose of the research was to quantify the occurrence of different stepping strategies during lateral step initiation in older adults and to relate the stepping responses to retrospective history of falls. Seventy community-ambulating older adults (mean age 76 y, range 70–94 y) performed voluntary lateral steps as quickly as possible to the right or left in response to a visual cue, in a blocked design. Vertical ground reaction forces were measured using a forceplate, and the number and latency of postural adjustments were quantified. Subjects were assigned to groups based on their stepping strategy. The frequency of trials with one or two postural adjustments was compared with data from 20 younger adults (mean age 38 y, range 21–58 y). Logistic regression was used to relate presence of a fall in the previous year with the number and latency of postural adjustments. In comparison with younger adults, who almost always demonstrated one postural adjustment when stepping laterally, older adults constituted a continuous distribution in the percentage of step trials made with one postural adjustment (from 0% to 100% of trials). Latencies of the initial postural adjustment and foot liftoff varied depending on the number of postural adjustments made. A history of falls was associated a larger percentage of two postural adjustments, and a longer latency of foot liftoff. In conclusion, the number and latency of postural adjustments made during voluntary lateral stepping provides additional evidence that lateral control of posture may be a critical indicator of aging. PMID:24295896

Control of Task Sequences: What Is the Role of Language?

ERIC Educational Resources Information Center

Mayr, Ulrich; Kleffner-Canucci, Killian; Kikumoto, Atsushi; Redford, Melissa A.

2014-01-01

It is almost a truism that language aids serial-order control through self-cuing of upcoming sequential elements. We measured speech onset latencies as subjects performed hierarchically organized task sequences while "thinking aloud" each task label. Surprisingly, speech onset latencies and response times (RTs) were highly synchronized,…

Cue reactivity in non-daily smokers: effects on craving and on smoking behavior.

PubMed

Shiffman, Saul; Dunbar, Michael S; Kirchner, Thomas R; Li, Xiaoxue; Tindle, Hilary A; Anderson, Stewart J; Scholl, Sarah M; Ferguson, Stuart G

2013-03-01

Non-daily, or intermittent smokers (ITS), are increasingly prevalent. Their smoking may be more situational than that of daily smokers (DS), and thus is hypothesized to be more influenced by cues. To assess ITS' response to cues, and compare it to that of DS. Samples of 239 ITS and 207 DS (previously reported in Shiffman et al. 2012a) were studied in 2,586 laboratory cue-reactivity sessions. Craving (Questionnaire of Smoking Urges) and smoking (probability, latency, puff parameters, and carbon monoxide increases) in response to cues was assessed following exposure to neutral cues and cues related to smoking, alcohol, negative affect, positive affect, and smoking prohibitions. Mixed effects models, generalized estimating equations and random-effects survival analyses were used to assess response to cues and differences between DS and ITS. ITS' craving increased following exposure to smoking and alcohol cues and decreased following positive affect cues, but cues had little effect on smoking behaviors. Cue reactivity was similar in ITS and DS. Among ITS, craving intensity predicted smoking probability, latency, and intensity, and the effects on latency were stronger among ITS than DS. Contrary to hypotheses, ITS were not more responsive to laboratory cues than DS. Results show that ITS do experience craving and craving increases that are then associated with smoking.

Auditory brainstem response latency in forward masking, a marker of sensory deficits in listeners with normal hearing thresholds

PubMed Central

Mehraei, Golbarg; Gallardo, Andreu Paredes; Shinn-Cunningham, Barbara G.; Dau, Torsten

2017-01-01

In rodent models, acoustic exposure too modest to elevate hearing thresholds can nonetheless cause auditory nerve fiber deafferentation, interfering with the coding of supra-threshold sound. Low-spontaneous rate nerve fibers, important for encoding acoustic information at supra-threshold levels and in noise, are more susceptible to degeneration than high-spontaneous rate fibers. The change in auditory brainstem response (ABR) wave-V latency with noise level has been shown to be associated with auditory nerve deafferentation. Here, we measured ABR in a forward masking paradigm and evaluated wave-V latency changes with increasing masker-to-probe intervals. In the same listeners, behavioral forward masking detection thresholds were measured. We hypothesized that 1) auditory nerve fiber deafferentation increases forward masking thresholds and increases wave-V latency and 2) a preferential loss of low-SR fibers results in a faster recovery of wave-V latency as the slow contribution of these fibers is reduced. Results showed that in young audiometrically normal listeners, a larger change in wave-V latency with increasing masker-to-probe interval was related to a greater effect of a preceding masker behaviorally. Further, the amount of wave-V latency change with masker-to-probe interval was positively correlated with the rate of change in forward masking detection thresholds. Although we cannot rule out central contributions, these findings are consistent with the hypothesis that auditory nerve fiber deafferentation occurs in humans and may predict how well individuals can hear in noisy environments. PMID:28159652

Magnetoencephalographic Imaging of Auditory and Somatosensory Cortical Responses in Children with Autism and Sensory Processing Dysfunction

PubMed Central

Demopoulos, Carly; Yu, Nina; Tripp, Jennifer; Mota, Nayara; Brandes-Aitken, Anne N.; Desai, Shivani S.; Hill, Susanna S.; Antovich, Ashley D.; Harris, Julia; Honma, Susanne; Mizuiri, Danielle; Nagarajan, Srikantan S.; Marco, Elysa J.

2017-01-01

This study compared magnetoencephalographic (MEG) imaging-derived indices of auditory and somatosensory cortical processing in children aged 8–12 years with autism spectrum disorder (ASD; N = 18), those with sensory processing dysfunction (SPD; N = 13) who do not meet ASD criteria, and typically developing control (TDC; N = 19) participants. The magnitude of responses to both auditory and tactile stimulation was comparable across all three groups; however, the M200 latency response from the left auditory cortex was significantly delayed in the ASD group relative to both the TDC and SPD groups, whereas the somatosensory response of the ASD group was only delayed relative to TDC participants. The SPD group did not significantly differ from either group in terms of somatosensory latency, suggesting that participants with SPD may have an intermediate phenotype between ASD and TDC with regard to somatosensory processing. For the ASD group, correlation analyses indicated that the left M200 latency delay was significantly associated with performance on the WISC-IV Verbal Comprehension Index as well as the DSTP Acoustic-Linguistic index. Further, these cortical auditory response delays were not associated with somatosensory cortical response delays or cognitive processing speed in the ASD group, suggesting that auditory delays in ASD are domain specific rather than associated with generalized processing delays. The specificity of these auditory delays to the ASD group, in addition to their correlation with verbal abilities, suggests that auditory sensory dysfunction may be implicated in communication symptoms in ASD, motivating further research aimed at understanding the impact of sensory dysfunction on the developing brain. PMID:28603492

Amplitude and timing of somatosensory cortex activity in task-specific focal hand dystonia.

PubMed

Dolberg, Rebecca; Hinkley, Leighton B N; Honma, Susanne; Zhu, Zhao; Findlay, Anne M; Byl, Nancy N; Nagarajan, Srikantan S

2011-12-01

Task-specific focal hand dystonia (tspFHD) is a movement disorder diagnosed in individuals performing repetitive hand behaviors. The extent to which processing anomalies in primary sensory cortex extend to other regions or across the two hemispheres is presently unclear. In response to low/high rate and novel tactile stimuli on the affected and unaffected hands, magnetoencephalography (MEG) was used to elaborate activity timing and amplitude in the primary somatosensory (S1) and secondary somatosensory/parietal ventral (S2/PV) cortices. MEG and clinical performance measures were collected from 13 patients and matched controls. Compared to controls, subjects with tspFHD had increased response amplitude in S2/PV bilaterally in response to high rate and novel stimuli. Subjects with tspFHD also showed increased response latency (low rate, novel) of the affected digits in contralateral S1. For high rate, subjects with tspFHD showed increased response latency in ipsilateral S1 and S2/PV bilaterally. Activation differences correlated with functional sensory deficits (predicting a latency shift in S1), motor speed and muscle strength. There are objective differences in the amplitude and timing of activity for both hands across contralateral and ipsilateral somatosensory cortex in patients with tspFHD. Knowledge of cortical processing abnormalities across S1 and S2/PV in dystonia should be applied towards the development of learning-based sensorimotor interventions. Copyright © 2011 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.

Postural responses to yaw rotation of support surface.

PubMed

Chen, Chiung-Ling; Lou, Shu-Zon; Wu, Hong-Wen; Wu, Shyi-Kuen; Yeung, Kwok-Tak; Su, Fong-Chin

2013-02-01

The purposes of this study were to investigate EMG and kinematic responses to yaw rotation of a support surface. Twenty people participated in four conditions, i.e., two velocities (240°/s, 120°/s) and two amplitudes (30°, 15°). Longer latency and smaller muscle responses were induced for yaw rotation, and distal ankle and knee muscles were activated earlier than trunk and neck muscles. Joint kinematics demonstrated larger angular displacements in axial rotation. Velocity and amplitude did not affect onset latency or magnitude of muscle activation but had significant effects on joint movements and COM displacements. Preliminary information about normative data of healthy subjects was obtained, and questions were generated about optimal velocity and amplitude test protocols that require further investigation. Copyright © 2012 Elsevier B.V. All rights reserved.

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

PubMed

Niemczak, Christopher E; Vander Werff, Kathy R

2018-05-18

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

The Effects of Spatial Stimulus-Response Compatibility on Choice Time Production Accuracy and Variability

ERIC Educational Resources Information Center

Rakitin, Brian C.

2005-01-01

Five experiments examined the relations between timing and attention using a choice time production task in which the latency of a spatial choice response is matched to a target interval (3 or 5 s). Experiments 1 and 2 indicated that spatial stimulus-response incompatibility increased nonscalar timing variability without affecting timing accuracy…

Maturation of auditory neural processes in autism spectrum disorder - A longitudinal MEG study.

PubMed

Port, Russell G; Edgar, J Christopher; Ku, Matthew; Bloy, Luke; Murray, Rebecca; Blaskey, Lisa; Levy, Susan E; Roberts, Timothy P L

2016-01-01

Individuals with autism spectrum disorder (ASD) show atypical brain activity, perhaps due to delayed maturation. Previous studies examining the maturation of auditory electrophysiological activity have been limited due to their use of cross-sectional designs. The present study took a first step in examining magnetoencephalography (MEG) evidence of abnormal auditory response maturation in ASD via the use of a longitudinal design. Initially recruited for a previous study, 27 children with ASD and nine typically developing (TD) children, aged 6- to 11-years-old, were re-recruited two to five years later. At both timepoints, MEG data were obtained while participants passively listened to sinusoidal pure-tones. Bilateral primary/secondary auditory cortex time domain (100 ms evoked response latency (M100)) and spectrotemporal measures (gamma-band power and inter-trial coherence (ITC)) were examined. MEG measures were also qualitatively examined for five children who exhibited "optimal outcome", participants who were initially on spectrum, but no longer met diagnostic criteria at follow-up. M100 latencies were delayed in ASD versus TD at the initial exam (~ 19 ms) and at follow-up (~ 18 ms). At both exams, M100 latencies were associated with clinical ASD severity. In addition, gamma-band evoked power and ITC were reduced in ASD versus TD. M100 latency and gamma-band maturation rates did not differ between ASD and TD. Of note, the cohort of five children that demonstrated "optimal outcome" additionally exhibited M100 latency and gamma-band activity mean values in-between TD and ASD at both timepoints. Though justifying only qualitative interpretation, these "optimal outcome" related data are presented here to motivate future studies. Children with ASD showed perturbed auditory cortex neural activity, as evidenced by M100 latency delays as well as reduced transient gamma-band activity. Despite evidence for maturation of these responses in ASD, the neural abnormalities in ASD persisted across time. Of note, data from the five children whom demonstrated "optimal outcome" qualitatively suggest that such clinical improvements may be associated with auditory brain responses intermediate between TD and ASD. These "optimal outcome" related results are not statistically significant though, likely due to the low sample size of this cohort, and to be expected as a result of the relatively low proportion of "optimal outcome" in the ASD population. Thus, further investigations with larger cohorts are needed to determine if the above auditory response phenotypes have prognostic utility, predictive of clinical outcome.

Sex Differences in Orienting to Pictures with and without Humans: Evidence from the Cardiac Evoked Response (ECR) and the Cortical Long Latency Parietal Positivity (LPP)

PubMed Central

Althaus, Monika; Groen, Yvonne; van der Schaft, Lutske; Minderaa, Ruud B.; Tucha, Oliver; Mulder, Lambertus J. M.; Wijers, Albertus A.

2014-01-01

Objective This study investigated the effect of social relevance in affective pictures on two orienting responses, i.e. the evoked cardiac response (ECR), and a long latency cortical evoked potential (LPP) and whether this effect would differ between males and females. Assuming that orienting to affective social information is fundamental to experiencing affective empathy, associations between self-report measures of empathy and the two orienting responses were investigated. Method ECRs were obtained from 34 female and 30 male students, and LPPs from 25 female and 27 male students viewing 414 pictures from the International Affective Picture System. Pictures portrayed pleasant, unpleasant and neutral scenes with and without humans. Results Both the ECR and LPP showed the largest response to pictures with humans in unpleasant situations. For both measures, the responses to pictures with humans correlated with self-report measures of empathy. While we found a greater male than female responsiveness to the pictures without humans in the ECR, a greater female than male responsiveness was observed in the LPP response to pictures with humans. Conclusion and Significance The sensitivity of these orienting responses to social relevance and their differential contribution to the prediction of individual differences underline the validity of their combined use in clinical studies investigating individuals with social disabilities. PMID:25330003

Healthy-side dominance of middle- and long-latency neuromagnetic fields in idiopathic sudden sensorineural hearing loss.

PubMed

Li, L P H; Shiao, A S; Chen, L F; Niddam, D M; Chang, S Y; Lien, C F; Lee, S K; Hsieh, J C

2006-08-01

Any lesion along the neural axis may induce a subsequent functional reorganization at the level above. The present study used magnetoencephalography to investigate auditory-evoked magnetic fields [a component of the middle-latency auditory evoked fields peaking at approximately 50 ms (P50m) and a component of the long-latency auditory evoked fields peaking at approximately 100 ms (N100m)] on stimulation of both healthy and affected ears in patients with acute unilateral idiopathic sudden sensorineural hearing loss (ISSNHL) of moderate degree in order to elucidate the functional plasticity of the auditory system. Sixteen right-handed, previously untreated adult patients with acute unilateral left (n = 8) or right (n = 8) ISSNHL of moderate degree were studied. Sixteen right-handed healthy volunteers with normal hearing served as control. Auditory neuromagnetic responses, measured by a whole-head 306-channel neuromagnetometer, were detected by monaural tone stimulation applied to affected and healthy ears, respectively, in different sessions. Intragroup and intergroup interhemispheric differences of peak dipole strengths and latencies of P50m and N100m, respectively, to monaural tones were evaluated. Healthy-side amplitude dominance of both P50m and N100m was found in ISSNHL, i.e. contralateral dominance was preserved on affected-ear stimulation but ipsilateral dominance was seen on healthy-ear stimulation. The phenomena could be attributed to the combined contralateral attenuation and ipsilateral enhancement of P50m and N100m activity in response to healthy-ear stimulation. Our findings confirmed that functional modulation can occur within the first few tens of milliseconds of evoked response at the auditory cortex in ISSNHL. The mechanisms of healthy-side dominance might be ascribed to a functional retune of auditory pathways, i.e. conjoined contralateral inhibition and ipsilateral excitation of the auditory pathway in response to healthy-ear stimulation. The effect could be registered in cortical responses.

Seeing the hand while reaching speeds up on-line responses to a sudden change in target position

PubMed Central

Reichenbach, Alexandra; Thielscher, Axel; Peer, Angelika; Bülthoff, Heinrich H; Bresciani, Jean-Pierre

2009-01-01

Goal-directed movements are executed under the permanent supervision of the central nervous system, which continuously processes sensory afferents and triggers on-line corrections if movement accuracy seems to be compromised. For arm reaching movements, visual information about the hand plays an important role in this supervision, notably improving reaching accuracy. Here, we tested whether visual feedback of the hand affects the latency of on-line responses to an external perturbation when reaching for a visual target. Two types of perturbation were used: visual perturbation consisted in changing the spatial location of the target and kinesthetic perturbation in applying a force step to the reaching arm. For both types of perturbation, the hand trajectory and the electromyographic (EMG) activity of shoulder muscles were analysed to assess whether visual feedback of the hand speeds up on-line corrections. Without visual feedback of the hand, on-line responses to visual perturbation exhibited the longest latency. This latency was reduced by about 10% when visual feedback of the hand was provided. On the other hand, the latency of on-line responses to kinesthetic perturbation was independent of the availability of visual feedback of the hand. In a control experiment, we tested the effect of visual feedback of the hand on visual and kinesthetic two-choice reaction times – for which coordinate transformation is not critical. Two-choice reaction times were never facilitated by visual feedback of the hand. Taken together, our results suggest that visual feedback of the hand speeds up on-line corrections when the position of the visual target with respect to the body must be re-computed during movement execution. This facilitation probably results from the possibility to map hand- and target-related information in a common visual reference frame. PMID:19675067

Neuronal activity in the lateral cerebellum of the cat related to visual stimuli at rest, visually guided step modification, and saccadic eye movements

PubMed Central

Marple-Horvat, D E; Criado, J M; Armstrong, D M

1998-01-01

The discharge patterns of 166 lateral cerebellar neurones were studied in cats at rest and during visually guided stepping on a horizontal circular ladder. A hundred and twelve cells were tested against one or both of two visual stimuli: a brief full-field flash of light delivered during eating or rest, and a rung which moved up as the cat approached. Forty-five cells (40%) gave a short latency response to one or both of these stimuli. These visually responsive neurones were found in hemispheral cortex (rather than paravermal) and the lateral cerebellar nucleus (rather than nucleus interpositus).Thirty-seven cells (of 103 tested, 36%) responded to flash. The cortical visual response (mean onset latency 38 ms) was usually an increase in Purkinje cell discharge rate, of around 50 impulses s−1 and representing 1 or 2 additional spikes per trial (1.6 on average). The nuclear response to flash (mean onset latency 27 ms) was usually an increased discharge rate which was shorter lived and converted rapidly to a depression of discharge or return to control levels, so that there were on average only an additional 0.6 spikes per trial. A straightforward explanation of the difference between the cortical and nuclear response would be that the increased inhibitory Purkinje cell output cuts short the nuclear response.A higher proportion of cells responded to rung movement, sixteen of twenty-five tested (64%). Again most responded with increased discharge, which had longer latency than the flash response (first change in dentate output ca 60 ms after start of movement) and longer duration. Peak frequency changes were twice the size of those in response to flash, at 100 impulses s−1 on average and additional spikes per trial were correspondingly 3–4 times higher. Both cortical and nuclear responses were context dependent, being larger when the rung moved when the cat was closer than further away.A quarter of cells (20 of 84 tested, 24%) modulated their activity in advance of saccades, increasing their discharge rate. Four-fifths of these were non-reciprocally directionally selective. Saccade-related neurones were usually susceptible to other influences, i.e. their activity was not wholly explicable in terms of saccade parameters.Substantial numbers of visually responsive neurones also discharged in relation to stepping movements while other visually responsive neurones discharged in advance of saccadic eye movements. And more than half the cells tested were active in relation both to eye movements and to stepping movements. These combinations of properties qualify even individual cerebellar neurones to participate in the co-ordination of visually guided eye and limb movements. PMID:9490874

Lagged association between geomagnetic activity and diminished nocturnal pain thresholds in mice.

PubMed

Galic, M A; Persinger, M A

2007-10-01

A wide variety of behaviors in several species has been statistically associated with the natural variations in geomagnetism. To examine whether changes in geomagnetic activity are associated with pain thresholds, adult mice were exposed to a hotplate paradigm once weekly for 52 weeks during the dark cycle. Planetary A index values from the previous 6 days of a given hotplate session were correlated with the mean response latency for subjects to the thermal stimulus. We found that hotplate latency was significantly (P < 0.05) and inversely correlated (rho = -0.25) with the daily geomagnetic intensity 3 days prior to testing. Therefore, if the geomagnetic activity was greater 3 days before a given hotplate trial, subjects tended to exhibit shorter response latencies, suggesting lower pain thresholds or less analgesia. These results are supported by related experimental findings and suggest that natural variations in geomagnetic intensity may influence nociceptive behaviors in mice. (c) 2007 Wiley-Liss, Inc.

Daily family stress and HPA axis functioning during adolescence: The moderating role of sleep

PubMed Central

Chiang, Jessica J.; Tsai, Kim M.; Park, Heejung; Bower, Julienne E.; Almeida, David M.; Dahl, Ronald E.; Irwin, Michael R.; Seeman, Teresa E.; Fuligni, Andrew J.

2017-01-01

The present study examined the moderating role of sleep in the association between family demands and conflict and hypothalamic-pituitary-adrenal (HPA) axis functioning in a sample of ethnically diverse adolescents (n = 316). Adolescents completed daily diary reports of family demands and conflict for 15 days, and wore actigraph watches during the first 8 nights to assess sleep. Participants also provided five saliva samples for 3 consecutive days to assess diurnal cortisol rhythms. Regression analyses indicated that sleep latency and efficiency moderated the link between family demands and the cortisol awakening response. Specifically, family demands were related to a smaller cortisol awakening response only among adolescents with longer sleep latency and lower sleep efficiency. These results suggest that certain aspects of HPA axis functioning may be sensitive to family demands primarily in the context of longer sleep latency and lower sleep efficiency. PMID:27235639

Brain stem auditory-evoked response in the nonanesthetized horse and pony.

PubMed

Marshall, A E

1985-07-01

The brain stem auditory-evoked response (BAER) was measured in 10 horses and 7 ponies under conditions suitable for clinical diagnostic testing. Latencies of 5 vertex-positive peaks and interpeak latency and amplitude ratio on the 1st and 4th peaks were determined. Data from horses and ponies were analyzed separately and were compared. The stimulus was a click (n = 3,000) ranging from 10- to 90-dB hearing level (HL). Neither horses nor ponies responded with a BAER at 10 dB nor did they give reliable responses at less than 50 dB. The 2nd of the BAER waves appeared in the record at lower stimulus intensities than did the 1st wave for the horse and pony. Horses and ponies had a decreasing latency for all waves, as a result of increasing stimulus intensity. Latencies were shorter for the ponies than for the horses at all stimulus intensities for the 1st, 2nd, 3rd, and 4th waves, but not the 5th wave. At 60-dB HL, the mean latencies for the 1st through 5th wave, respectively, for the horse were 1.73, 3.08, 3.93, 4.98, and 6.00 ms and for the pony 1.48, 2.73, 3.50, 4.56, and 6.58 ms. Interpeak latencies, 1st to 4th wave, averaged 3.22 ms (horse) and 3.11 ms (pony) for all stimulus intensities from 50- to 90-dB HL and had a tendency to decrease slightly as stimulus intensity increased. Amplitude ratios (4th wave/1st wave) were less than 1 for all stimulus intensities in the horse. In the pony, the ratio was less than 1 at greater than or equal to 70-dB HL and greater than 1 at less than or equal to 60-dB HL.

Delay of cognitive gamma responses in Alzheimer's disease

PubMed Central

Başar, Erol; Emek-Savaş, Derya Durusu; Güntekin, Bahar; Yener, Görsev G.

2016-01-01

Event-related oscillations (EROs) reflect cognitive brain dynamics, while sensory-evoked oscillations (SEOs) reflect sensory activities. Previous reports from our lab have shown that those with Alzheimer's disease (AD) or mild cognitive impairment (MCI) have decreased activity and/or coherence in delta, theta, alpha and beta cognitive responses. In the current study, we investigated gamma responses in visual SEO and ERO in 15 patients with AD and in 15 age-, gender- and education-matched healthy controls. The following parameters were analyzed over the parietal-occipital regions in both groups: (i) latency of the maximum gamma response over a 0–800 ms time window; (ii) the maximum peak-to-peak amplitudes for each participant's averaged SEO and ERO gamma responses in 3 frequency ranges (25–30, 30–35, 40–48 Hz); and (iii) the maximum peak-to-peak amplitudes for each participant's averaged SEO and ERO gamma responses over a 0–800 ms time block containing four divided time windows (0–200, 200–400, 400–600, and 600–800 ms). There were main group effects in terms of both latency and peak-to-peak amplitudes of gamma ERO. However, peak-to-peak gamma ERO amplitude differences became noticeable only when the time block was divided into four time windows. SEO amplitudes in the 25–30 Hz frequency range of the 0–200 ms time window over the left hemisphere were greater in the healthy controls than in those with AD. Gamma target ERO latency was delayed up to 138 ms in AD patients when compared to healthy controls. This finding may be an effect of lagged neural signaling in cognitive circuits, which is reflected by the delayed gamma responses in those with AD. Based on the results of this study, we propose that gamma responses should be examined in a more detailed fashion using multiple frequency and time windows. PMID:26937378

CMV immune evasion and manipulation of the immune system with aging.

PubMed

Jackson, Sarah E; Redeker, Anke; Arens, Ramon; van Baarle, Debbie; van den Berg, Sara P H; Benedict, Chris A; Čičin-Šain, Luka; Hill, Ann B; Wills, Mark R

2017-06-01

Human cytomegalovirus (HCMV) encodes numerous proteins and microRNAs that function to evade the immune response and allow the virus to replicate and disseminate in the face of a competent innate and acquired immune system. The establishment of a latent infection by CMV, which if completely quiescent at the level of viral gene expression would represent an ultimate in immune evasion strategies, is not sufficient for lifelong persistence and dissemination of the virus. CMV needs to reactivate and replicate in a lytic cycle of infection in order to disseminate further, which occurs in the face of a fully primed secondary immune response. Without reactivation, latency itself would be redundant for the virus. It is also becoming clear that latency is not a totally quiescent state, but is characterized by limited viral gene expression. Therefore, the virus also needs immune evasion strategies during latency. An effective immune response to CMV is required or viral replication will cause morbidity and ultimately mortality in the host. There is clearly a complex balance between virus immune evasion and host immune recognition over a lifetime. This poses the important question of whether long-term evasion or manipulation of the immune response driven by CMV is detrimental to health. In this meeting report, three groups used the murine model of CMV (MCMV) to examine if the contribution of the virus to immune senescence is set by the (i) initial viral inoculum, (ii) inflation of T cell responses, (iii) or the balance between functionally distinct effector CD4+ T cells. The work of other groups studying the CMV response in humans is discussed. Their work asks whether the ability to make immune responses to new antigens is compromised by (i) age and HCMV carriage, (ii) long-term exposure to HCMV giving rise to an overall immunosuppressive environment and increased levels of latent virus, or (iii) adapted virus mutants (used as potential vaccines) that have the capacity to elicit conventional and unconventional T cell responses.

Factors influencing the response latencies of subnormal children in naming pictures.

PubMed

Elliott, C

1978-08-01

The times taken to name 56 drawings of objects on five separate occasions were analysed for 21 ESN(M) and 21 ESN(S) children, matched for picture-naming vocabulary. The ESN(S) group not only had a higher mean response latency but also showed greater inter- and intra-subject variance. Nine objects were selected whose names have a Thorndike-Lorge language frequency of 50 words per million or greater, and nine others were selected with a frequency of less than 50 words per million. Each object was drawn in two ways, one giving a two-dimensional outline with the addition of important detail, the other drawing also incorporating cues indicating the depth of the object. An analysis of variance of the children's latencies in naming the selected 36 pictures of 18 objects over five trials indicated that the method of drawing had no effect upon naming latencies. Pictures with high-frequency names were named faster than those with lower frequency names, the ESN(S) group showing a greater rate of increase in naming latency for the lower frequency words than the ESN(M) children. Results were discussed in terms of the Oldfield and Lachman models of lexical memory storage and of the search processes required for the retrieval of names.

Striate cortical contribution to the transcorneal electrically evoked response of the visual system.

PubMed

Shimazu, K; Miyake, Y; Fukatsu, Y; Watanabe, S

1996-01-01

Analyses of current-source-density (CSD) and multiple unit activity (MUA) in area 17 of the cat were performed to determine the sources of the cortical transcorneal electrically evoked response. Cortical field potential, CSD and MUA profiles were obtained with multi-electrodes. CSD findings include: current sinks (inward cell membrane current) within 20 ms latency, in layers 4 and 6 of the striate cortex; current sinks corresponding to N3 (negative component of the EER; latency, 35 ms) in layer 4 and lower layer 3 with current sources (outward cell membrane current) for N3 in the supragranular layers; current sinks with latency over 40 ms in the supragranular layers. In the layers 4 and 6, simultaneous MUA was seen. When the stimulus frequency was increased or with dual stimulation, the N3 current sinks were decreased. This indicates that N1 (latency, 9 ms) and N2 (latency, 20 ms) reflect near-field potentials in layers 4 and 6, generated by geniculocortical afferents, and that N3 is a post- and polysynaptic component. It is also suggested that dipoles composed of cell bodies and the apical dendrites of pyramidal cells of layer 3, generated by satellite cells in layer 4, play a major role in generating N3.

Idiopathic Hypersomnia: A Study of 77 Cases

PubMed Central

Anderson, Kirstie N.; Pilsworth, Samantha; Sharples, Linda D.; Smith, Ian E.; Shneerson, John M.

2007-01-01

Study Objectives: To review the clinical and polysomnographic characteristics of idiopathic hypersomnia as well as the long-term response to treatment. Setting: The Respiratory Support and Sleep Centre at Papworth Hospital, Cambridge, UK. Patients and Design: A large database of more than 6000 patients with sleep disorders was reviewed. A retrospective study of the clinical and polysomnographic characteristics of 77 patients with idiopathic hypersomnia was performed. Comparison with a similar group of patients with narcolepsy was performed. The response to drug treatment was assessed in 61 patients over a mean follow-up of 3.8 years. Measurements and Results: Idiopathic hypersomnia was 60% as prevalent as narcolepsy. Comparison with a similar group of patients with narcolepsy showed that those with idiopathic hypersomnia were more likely to have prolonged unrefreshing daytime naps, a positive family history, increased slow-wave sleep, and a longer sleep latency on the Multiple Sleep Latency Test. The results of the Multiple Sleep Latency Test were not helpful in predicting disease severity or treatment response. The clinical features were heterogeneous and of variable severity. The majority of patients with idiopathic hypersomnia had symptoms that remained stable over many years, but 11% had spontaneous remission, which was never seen in narcolepsy. Two thirds of patients with idiopathic hypersomnolence had a sustained improvement in daytime somnolence with medication, although a third needed high doses or combinations of drugs. Conclusions: Idiopathic hypersomnolence has characteristic clinical and polysomnographic features but the prolonged latency on the Multiple Sleep Latency Test raises doubt about the validity of this test within the current diagnostic criteria. The disease often responds well to treatment and a substantial minority of patients appear to spontaneously improve. Citation: Anderson KN; Pilsworth S; Sharples LD; Smith IE; Shneerson JM. Idiopathic hypersomnia: a study of 77 cases. SLEEP 2007;30(10):1274-1281. PMID:17969461

Analysis of vestibular testing in patients with vestibular schwannoma based on the nerve of origin, the localization, and the size of the tumor.

PubMed

Suzuki, Mitsuya; Yamada, Chikako; Inoue, Rika; Kashio, Akinori; Saito, Yuki; Nakanishi, Wakako

2008-10-01

We aimed to analyze the factors influencing caloric response and vestibular evoked myogenic potential (VEMP) in vestibular schwannoma. The subjects comprised 130 patients with unilateral vestibular schwannoma pathologically diagnosed by surgery. Caloric response and the amplitude and latency of VEMP were measured and analyzed based on the nerve of origin, localization, and size of the tumor. The tumors were classified into 3 types based on localization: intracanalicular, intermediate, and medial; and into 4 grades based on size: 9 mm or less, 10 to 19 mm, 20 to 29 mm, and 30 mm or greater. : Abnormal rates of caloric response and VEMP in patients with tumors arising from the superior vestibular nerve were not significantly different from those in patients with tumors of the inferior vestibular nerve. In the intermediate and medial type-but not in the intracanalicular type-a significant difference in tumor size was observed between patients with normal caloric response and those with canal paresis as also between patients with normal VEMP and those with abnormal VEMP. In patients with tumors that maximally measured 10 to 19 mm or of the intermediate type, the p- and n-wave latencies of VEMP were significantly prolonged compared with those in the normal opposite ear. 1) The nerve of origin of tumors cannot be predicted based on caloric response and VEMP. 2) In the intermediate and medial types, caloric response and the VEMP amplitude are significantly diminished in association with an increase in tumor size. 3) Prolonged VEMP latencies seem to be not only caused by tumor compression to the brainstem or vestibular spinal tract but also by tumor compression isolated to the inferior vestibular nerve.

Reversal learning in gonadectomized marmosets with and without hormone replacement: are males more sensitive to punishment?

PubMed

LaClair, Matthew; Lacreuse, Agnès

2016-05-01

This study examined sex differences in executive function in middle-aged gonadectomized marmosets (Callithrix jacchus) with or without hormonal replacement. We tested ten castrated male (mean age 5.5 years) marmosets treated with testosterone cypionate (T, n = 5) or vehicle (n = 5) on Reversal Learning, which contributes to cognitive flexibility, and the Delayed Response task, measuring working memory. Their performance was compared to that of 11 ovariectomized females (mean age = 3.7 years) treated with Silastic capsules filled with 17-β estradiol (E2, n = 6) or empty capsules (n = 5), previously tested on the same tasks (Lacreuse et al. in J Neuroendocrinol 26:296-309, 2014. doi: 10.1111/jne.12147). Behavioral observations were conducted daily. Females exhibited more locomotor behaviors than males. Males and females did not differ in the number of trials taken to reach criterion on the reversals, but males had significantly longer response latencies, regardless of hormone replacement. They also had a greater number of refusals than females. Additionally, both control and T-treated males, but not females, had slower responses on incorrect trials, suggesting that males were making errors due to distraction, lack of motivation or uncertainty. Furthermore, although both males and females had slower responding following an incorrect compared to a correct trial, the sex difference in response latencies was disproportionally large following an incorrect trial. No sex difference was found in the Delayed Response task. Overall, slower response latencies in males than females during Reversal Learning, especially during and following an incorrect trial, may reflect greater sensitivity to punishment (omission of reward) and greater performance monitoring in males, compared to females. Because these differences occurred in gonadectomized animals and regardless of hormone replacement, they may be organized early in life.

Mental fatigue and impaired response processes: event-related brain potentials in a Go/NoGo task.

PubMed

Kato, Yuichiro; Endo, Hiroshi; Kizuka, Tomohiro

2009-05-01

The effects of mental fatigue on the availability of cognitive resources and associated response-related processes were examined using event-related brain potentials. Subjects performed a Go/NoGo task for 60 min. Reaction time, number of errors, and mental fatigue scores all significantly increased with time spent on the task. The NoGo-P3 amplitude significantly decreased with time on task, but the Go-P3 amplitude was not modulated. The amplitude of error-related negativity (Ne/ERN) also decreased with time on task. These results indicate that mental fatigue attenuates resource allocation and error monitoring for NoGo stimuli. The Go- and NoGo-P3 latencies both increased with time on task, indicative of a delay in stimulus evaluation time due to mental fatigue. NoGo-N2 latency increased with time on task, but NoGo-N2 amplitude was not modulated. The amplitude of response-locked lateralized readiness potential (LRP) significantly decreased with time on task. Mental fatigue appears to slows down the time course of response inhibition, and impairs the intensity of response execution.

Auditory brainstem response in neonates: influence of gender and weight/gestational age ratio

PubMed Central

Angrisani, Rosanna M. Giaffredo; Bautzer, Ana Paula D.; Matas, Carla Gentile; de Azevedo, Marisa Frasson

2013-01-01

OBJECTIVE: To investigate the influence of gender and weight/gestational age ratio on the Auditory Brainstem Response (ABR) in preterm (PT) and term (T) newborns. METHODS: 176 newborns were evaluated by ABR; 88 were preterm infants - 44 females (22 small and 22 appropriate for gestational age) and 44 males (22 small and 22 appropriate for gestational age). The preterm infants were compared to 88 term infants - 44 females (22 small and 22 appropriate for gestational age) and 44 males (22 small and 22 appropriate for gestational age). All newborns had bilateral presence of transient otoacoustic emissions and type A tympanometry. RESULTS: No interaural differences were found. ABR response did not differentiate newborns regarding weight/gestational age in males and females. Term newborn females showed statistically shorter absolute latencies (except on wave I) than males. This finding did not occur in preterm infants, who had longer latencies than term newborns, regardless of gender. CONCLUSIONS: Gender and gestational age influence term infants' ABR, with lower responses in females. The weight/gestational age ratio did not influence ABR response in either groups. PMID:24473955

Event related potentials during covert orientation of visual attention: effects of cue validity and directionality.

PubMed

Wright, M J; Geffen, G M; Geffen, L B

1995-10-01

Covert orientation of attention was studied in 30 adults who fixated warning cues and pressed a button at target onset. Directional cues (arrows) indicated the most probable (p = 0.8) side of target occurrence. Subjects responded fastest when validly cued, slowest to invalidly cued targets, and at an intermediate rate when the cue (a cross) was not directional. Directional cues took longer to evaluate (increased N1 and P2 latencies) and produced more focussed attention and greater response preparation (enhanced CNV and P3 amplitude) than non-directional cues. These findings indicate that the expectancy of a target can be manipulated by a spatial cue at three levels, sensory, attention, and response preparation, and lead to changes in the sensory perceptual processing of the target. Validly cued targets produced an increase in P1 amplitude reflecting attention enhanced sensory processing whereas invalidly cued targets increased N1 and P3 amplitudes reflecting the re-orientation of attention, and further processing and updating of information required of low probability stimuli respectively. P3 latency to invalidly cued targets was also delayed reflecting the additional processes required to shift attention to a new location. The P3 latency validity effect was smaller than that found for response time suggesting response execution may also be affected by spatial attention.

The chemical component of the mixed GF-TTMn synapse in Drosophila melanogaster uses acetylcholine as its neurotransmitter.

PubMed

Allen, Marcus J; Murphey, R K

2007-07-01

The largest central synapse in adult Drosophila is a mixed electro-chemical synapse whose gap junctions require the product of the shaking-B (shak-B) gene. Shak-B(2) mutant flies lack gap junctions at this synapse, which is between the giant fibre (GF) and the tergotrochanteral motor neuron (TTMn), but it still exhibits a long latency response upon GF stimulation. We have targeted the expression of the light chain of tetanus toxin to the GF, to block chemical transmission, in shak-B(2) flies. The long latency response in the tergotrochanteral muscle (TTM) was abolished indicating that the chemical component of the synapse mediates this response. Attenuation of GAL4-mediated labelling by a cha-GAL80 transgene, reveals the GF to be cholinergic. We have used a temperature-sensitive allele of the choline acetyltransferase gene (cha(ts2)) to block cholinergic synapses in adult flies and this also abolished the long latency response in shak-B(2) flies. Taken together the data provide evidence that both components of this mixed synapse are functional and that the chemical neurotransmitter between the GF and the TTMn is acetylcholine. Our findings show that the two components of this synapse can be separated to allow further studies into the mechanisms by which mixed synapses are built and function.

The chemical component of the mixed GF-TTMn synapse in Drosophila melanogaster uses acetylcholine as its neurotransmitter

PubMed Central

Allen, Marcus J; Murphey, R K

2007-01-01

The largest central synapse in adult Drosophila is a mixed electro-chemical synapse whose gap junctions require the product of the shaking-B (shak-B) gene. Shak-B2 mutant flies lack gap junctions at this synapse, which is between the giant fibre (GF) and the tergotrochanteral motor neuron (TTMn), but it still exhibits a long latency response upon GF stimulation. We have targeted the expression of the light chain of tetanus toxin to the GF, to block chemical transmission, in shak-B2 flies. The long latency response in the tergotrochanteral muscle (TTM) was abolished indicating that the chemical component of the synapse mediates this response. Attenuation of GAL4-mediated labelling by a cha-GAL80 transgene, reveals the GF to be cholinergic. We have used a temperature-sensitive allele of the choline acetyltransferase gene (chats2) to block cholinergic synapses in adult flies and this also abolished the long latency response in shak-B2 flies. Taken together the data provide evidence that both components of this mixed synapse are functional and that the chemical neurotransmitter between the GF and the TTMn is acetylcholine. Our findings show that the two components of this synapse can be separated to allow further studies into the mechanisms by which mixed synapses are built and function. PMID:17650116

Dopamine D1 receptors are responsible for stress-induced emotional memory deficit in mice.

PubMed

Wang, Yongfu; Wu, Jing; Zhu, Bi; Li, Chaocui; Cai, Jing-Xia

2012-03-01

It is established that stress impairs spatial learning and memory via the hypothalamus-pituitary-adrenal axis response. Dopamine D1 receptors were also shown to be responsible for a stress-induced deficit of working memory. However, whether stress affects the subsequent emotional learning and memory is not elucidated yet. Here, we employed the well-established one-trial step-through task to study the effect of an acute psychological stress (induced by tail hanging for 5, 10, or 20 min) on emotional learning and memory, and the possible mechanisms as well. We demonstrated that tail hanging induced an obvious stress response. Either an acute tail-hanging stress or a single dose of intraperitoneally injected dopamine D1 receptor antagonist (SCH23390) significantly decreased the step-through latency in the one-trial step-through task. However, SCH23390 prevented the acute tail-hanging stress-induced decrease in the step-through latency. In addition, the effects of tail-hanging stress and/or SCH23390 on the changes in step-through latency were not through non-memory factors such as nociceptive perception and motor function. Our data indicate that the hyperactivation of dopamine D1 receptors mediated the stress-induced deficit of emotional learning and memory. This study may have clinical significance given that psychological stress is considered to play a role in susceptibility to some mental diseases such as depression and post-traumatic stress disorder.

Noise-induced hearing loss alters the temporal dynamics of auditory-nerve responses

PubMed Central

Scheidt, Ryan E.; Kale, Sushrut; Heinz, Michael G.

2010-01-01

Auditory-nerve fibers demonstrate dynamic response properties in that they adapt to rapid changes in sound level, both at the onset and offset of a sound. These dynamic response properties affect temporal coding of stimulus modulations that are perceptually relevant for many sounds such as speech and music. Temporal dynamics have been well characterized in auditory-nerve fibers from normal-hearing animals, but little is known about the effects of sensorineural hearing loss on these dynamics. This study examined the effects of noise-induced hearing loss on the temporal dynamics in auditory-nerve fiber responses from anesthetized chinchillas. Post-stimulus time histograms were computed from responses to 50-ms tones presented at characteristic frequency and 30 dB above fiber threshold. Several response metrics related to temporal dynamics were computed from post-stimulus-time histograms and were compared between normal-hearing and noise-exposed animals. Results indicate that noise-exposed auditory-nerve fibers show significantly reduced response latency, increased onset response and percent adaptation, faster adaptation after onset, and slower recovery after offset. The decrease in response latency only occurred in noise-exposed fibers with significantly reduced frequency selectivity. These changes in temporal dynamics have important implications for temporal envelope coding in hearing-impaired ears, as well as for the design of dynamic compression algorithms for hearing aids. PMID:20696230

Deviance-Related Responses along the Auditory Hierarchy: Combined FFR, MLR and MMN Evidence.

PubMed

Shiga, Tetsuya; Althen, Heike; Cornella, Miriam; Zarnowiec, Katarzyna; Yabe, Hirooki; Escera, Carles

2015-01-01

The mismatch negativity (MMN) provides a correlate of automatic auditory discrimination in human auditory cortex that is elicited in response to violation of any acoustic regularity. Recently, deviance-related responses were found at much earlier cortical processing stages as reflected by the middle latency response (MLR) of the auditory evoked potential, and even at the level of the auditory brainstem as reflected by the frequency following response (FFR). However, no study has reported deviance-related responses in the FFR, MLR and long latency response (LLR) concurrently in a single recording protocol. Amplitude-modulated (AM) sounds were presented to healthy human participants in a frequency oddball paradigm to investigate deviance-related responses along the auditory hierarchy in the ranges of FFR, MLR and LLR. AM frequency deviants modulated the FFR, the Na and Nb components of the MLR, and the LLR eliciting the MMN. These findings demonstrate that it is possible to elicit deviance-related responses at three different levels (FFR, MLR and LLR) in one single recording protocol, highlight the involvement of the whole auditory hierarchy in deviance detection and have implications for cognitive and clinical auditory neuroscience. Moreover, the present protocol provides a new research tool into clinical neuroscience so that the functional integrity of the auditory novelty system can now be tested as a whole in a range of clinical populations where the MMN was previously shown to be defective.

Deviance-Related Responses along the Auditory Hierarchy: Combined FFR, MLR and MMN Evidence

PubMed Central

Shiga, Tetsuya; Althen, Heike; Cornella, Miriam; Zarnowiec, Katarzyna; Yabe, Hirooki; Escera, Carles

2015-01-01

The mismatch negativity (MMN) provides a correlate of automatic auditory discrimination in human auditory cortex that is elicited in response to violation of any acoustic regularity. Recently, deviance-related responses were found at much earlier cortical processing stages as reflected by the middle latency response (MLR) of the auditory evoked potential, and even at the level of the auditory brainstem as reflected by the frequency following response (FFR). However, no study has reported deviance-related responses in the FFR, MLR and long latency response (LLR) concurrently in a single recording protocol. Amplitude-modulated (AM) sounds were presented to healthy human participants in a frequency oddball paradigm to investigate deviance-related responses along the auditory hierarchy in the ranges of FFR, MLR and LLR. AM frequency deviants modulated the FFR, the Na and Nb components of the MLR, and the LLR eliciting the MMN. These findings demonstrate that it is possible to elicit deviance-related responses at three different levels (FFR, MLR and LLR) in one single recording protocol, highlight the involvement of the whole auditory hierarchy in deviance detection and have implications for cognitive and clinical auditory neuroscience. Moreover, the present protocol provides a new research tool into clinical neuroscience so that the functional integrity of the auditory novelty system can now be tested as a whole in a range of clinical populations where the MMN was previously shown to be defective. PMID:26348628

Air Pressure Responses to Sudden Vocal Tract Pressure Bleeds during Production of Stop Consonants: New Evidence of Aeromechanical Regulation.

ERIC Educational Resources Information Center

Zajac, David J.; Weissler, Mark C.

2004-01-01

Two studies were conducted to evaluate short-latency vocal tract air pressure responses to sudden pressure bleeds during production of voiceless bilabial stop consonants. It was hypothesized that the occurrence of respiratory reflexes would be indicated by distinct patterns of responses as a function of bleed magnitude. In Study 1, 19 adults…

Detectability of auditory signals presented without defined observation intervals

NASA Technical Reports Server (NTRS)

Watson, C. S.; Nichols, T. L.

1976-01-01

Ability to detect tones in noise was measured without defined observation intervals. Latency density functions were estimated for the first response following a signal and, separately, for the first response following randomly distributed instances of background noise. Detection performance was measured by the maximum separation between the cumulative latency density functions for signal-plus-noise and for noise alone. Values of the index of detectability, estimated by this procedure, were approximately those obtained with a 2-dB weaker signal and defined observation intervals. Simulation of defined- and non-defined-interval tasks with an energy detector showed that this device performs very similarly to the human listener in both cases.

Synchronized Astrocytic Ca2+ Responses in Neurovascular Coupling during Somatosensory Stimulation and for the Resting State.

PubMed

Gu, Xiaochun; Chen, Wei; Volkow, Nora D; Koretsky, Alan P; Du, Congwu; Pan, Yingtian

2018-06-26

The role of astrocytes in neurovascular coupling (NVC) is unclear. Here, we applied a multimodality imaging approach to concomitantly measure synchronized neuronal or astrocytic Ca 2+ and hemodynamic changes in the mouse somatosensory cortex at rest and during sensory electrical stimulation. Strikingly, we found that low-frequency stimulation (0.3-1 Hz), which consistently evokes fast neuronal Ca 2+ transients (6.0 ± 2.7 ms latency) that always precede vascular responses, does not always elicit astrocytic Ca 2+ transients (313 ± 65 ms latency). However, the magnitude of the hemodynamic response is increased when astrocytic transients occur, suggesting a facilitatory role of astrocytes in NVC. High-frequency stimulation (5-10 Hz) consistently evokes a large, delayed astrocytic Ca 2+ accumulation (3.48 ± 0.09 s latency) that is temporarily associated with vasoconstriction, suggesting a role for astrocytes in resetting NVC. At rest, neuronal, but not astrocytic, Ca 2+ fluctuations correlate with hemodynamic low-frequency oscillations. Taken together, these results support a role for astrocytes in modulating, but not triggering, NVC. Copyright © 2018 The Authors. Published by Elsevier Inc. All rights reserved.

Cortical inhibition effect in musicians and non-musicians using P300 with and without contralateral stimulation.

PubMed

Rabelo, Camila Maia; Neves-Lobo, Ivone Ferreira; Rocha-Muniz, Caroline Nunes; Ubiali, Thalita; Schochat, Eliane

2015-01-01

Musicians have more robust and efficient neural responses in the cortical and sub-cortical regions, demonstrating that musical experience benefits the processing of both non-linguistic and linguistic stimuli. This study aimed to verify P300's latency and amplitude behavioral using contralateral stimulation in musicians and non-musicians. This was a case-control study. Subjects were divided in two groups: musicians, comprising 30 professional musicians, and non-musicians, comprising 25 subjects without musical experience. The present study showed that the musicians had lower latencies and higher amplitudes than the non-musicians in the P300 without contralateral noise. For the P300 amplitude values, the difference between groups persisted, and the musicians presented significantly higher amplitude values compared with the non-musicians; additionally, the analysis of the noise effect on the P300 response showed that the latency values were significantly increased in the musicians. The central auditory nervous system of musicians presents peculiar characteristics of electrophysiological responses probably due to the plasticity imposed by musical practice. Copyright © 2014 Associação Brasileira de Otorrinolaringologia e Cirurgia Cérvico-Facial. Published by Elsevier Editora Ltda. All rights reserved.

Recognition errors suggest fast familiarity and slow recollection in rhesus monkeys

PubMed Central

Basile, Benjamin M.; Hampton, Robert R.

2013-01-01

One influential model of recognition posits two underlying memory processes: recollection, which is detailed but relatively slow, and familiarity, which is quick but lacks detail. Most of the evidence for this dual-process model in nonhumans has come from analyses of receiver operating characteristic (ROC) curves in rats, but whether ROC analyses can demonstrate dual processes has been repeatedly challenged. Here, we present independent converging evidence for the dual-process model from analyses of recognition errors made by rhesus monkeys. Recognition choices were made in three different ways depending on processing duration. Short-latency errors were disproportionately false alarms to familiar lures, suggesting control by familiarity. Medium-latency responses were less likely to be false alarms and were more accurate, suggesting onset of a recollective process that could correctly reject familiar lures. Long-latency responses were guesses. A response deadline increased false alarms, suggesting that limiting processing time weakened the contribution of recollection and strengthened the contribution of familiarity. Together, these findings suggest fast familiarity and slow recollection in monkeys, that monkeys use a “recollect to reject” strategy to countermand false familiarity, and that primate recognition performance is well-characterized by a dual-process model consisting of recollection and familiarity. PMID:23864646

Time course of discrimination between emotional facial expressions: the role of visual saliency.

PubMed

Calvo, Manuel G; Nummenmaa, Lauri

2011-08-01

Saccadic and manual responses were used to investigate the speed of discrimination between happy and non-happy facial expressions in two-alternative-forced-choice tasks. The minimum latencies of correct saccadic responses indicated that the earliest time point at which discrimination occurred ranged between 200 and 280ms, depending on type of expression. Corresponding minimum latencies for manual responses ranged between 440 and 500ms. For both response modalities, visual saliency of the mouth region was a critical factor in facilitating discrimination: The more salient the mouth was in happy face targets in comparison with non-happy distracters, the faster discrimination was. Global image characteristics (e.g., luminance) and semantic factors (i.e., categorical similarity and affective valence of expression) made minor or no contribution to discrimination efficiency. This suggests that visual saliency of distinctive facial features, rather than the significance of expression, is used to make both early and later expression discrimination decisions. Copyright © 2011 Elsevier Ltd. All rights reserved.

Response of cat cerebellar vermis induced by sound. II. The role of the mossy and climbing fibers in acoustic transmission to the cerebellar cortex and influence of stimuli parameters.

PubMed

Jastreboff, P J; Tarnecki, R

1975-01-01

Experiments were performed on cats under Chloralose or Nembutal anesthesia. The parameters of the acoustic click stimuli were found to have a strong influence on the responses registered from both the surface of the cerebellar vermis lobuli V up VII as well as from single units. It was shown that a stimulus frequency rate not greater than 1/2 s should be used, since higher frequencies caused strong attenuation of the response. The type of anesthesia did not change the latencies of reactions of both evoked potentials and single units. However, decreasing the strength of the click resulted in increased response latencies, in the case of single unit reactions. A very strong influence of weak visual stimuli on units was also observed. It is suggested that mossy fibers are the most important fibers in the transmission of acoustic information to the cerebellar cortex.

Effects of structured nontarget stimuli on saccadic latency.

PubMed

White, Brian J; Gegenfurtner, Karl R; Kerzel, Dirk

2005-06-01

It has been suggested that the remote distractor effect is the result of nontarget stimulation of a central region representing a collicular fixation zone near the time of target onset. The distributed network of the cells responsible for this effect is believed to extend over a large area, responding to distractors < or =10 deg in the periphery. Several studies also implicate the superior colliculus as the substrate behind an inhibited saccadic response arising from a display change. We investigated this further by using a patch of pink noise of various sizes as a nontarget stimulus. We show that the onset of a small patch (2.3 x 2.3 deg) of centrally displayed pink noise can produce a significant increase in saccadic latency to a simultaneously presented peripheral Gabor target. In contrast, a large patch (36 x 36 deg) of pink noise did not increase latency despite the fact that it also stimulated the region representing the fixation zone. Furthermore, only the large patch of noise facilitated latency when presented before target onset. We also examined the effect of patch sizes between these two extremes and found a steady decrease in latency as patch size increased. This confirms that nontarget stimulation of the region representing the fixation zone near the time of target onset is not in itself sufficient to produce the increase in latency typically found with remote distractors. The results are consistent with the idea that only a spatially confined object leads to a discharge of collicular fixation neurons.

Effects of examination stress on psychological responses, sleep and allergic symptoms in atopic and non-atopic students.

PubMed

Jernelöv, Susanna; Höglund, Caroline Olgart; Axelsson, John; Axén, Jennie; Grönneberg, Reidar; Grunewald, Johan; Stierna, Pontus; Lekander, Mats

2009-01-01

Recent findings indicate that atopics may be more vulnerable to stress than non-atopics. However, the roles of psychological well-being and sleep in this presumed increased sensitivity are not known. To investigate the effects of a brief naturalistic stressor on psychological responses, sleep, and allergic symptoms and to compare those responses between atopic and non-atopic individuals. We assessed atopic and non-atopic students during a period without and during a period with examinations. For both atopic and non-atopic students, tension, anxiety, and depression deteriorated in response to examination, as did sleep latency and sleep quality. Overall, atopics were more tense, had more anxiety, longer sleep latencies, and were less well rested than non-atopics. Non-atopic students rose from bed later during the examination period. In response to examination, atopic students reported increased frequency of stress behaviors (e.g., eating fast), while decreased stress behaviors were reported by non-atopic students. Allergic symptoms were not affected. Atopic students were worse off in aspects of psychological well-being and sleep, but displayed only partly stronger responses to a stressor compared to non-atopic students. In spite of a broad negative response to examination, allergic symptoms were not affected.

Postural responses to unexpected perturbations of balance during reaching

PubMed Central

Trivedi, Hari; Leonard, Julia A.; Ting, Lena H.; Stapley, Paul J.

2014-01-01

To study the interaction between feedforward and feedback modes of postural control, we investigated postural responses during unexpected perturbations of the support surface that occurred during forward reaching in a standing position. We examined postural responses in lower limb muscles of 9 human subjects. Baseline measures were obtained when subjects executed reaching movements to a target placed in front of them (R condition) and during postural responses to forward and backward support-surface perturbations (no reaching, P condition) during quiet stance. Perturbations were also given at different delays after the onset of reaching movements (RP conditions) as well as with the arm extended in the direction of the target, but not reaching (P/AE condition). Results showed that during perturbations to reaching (RP), the initial automatic postural response, occurring around 100 ms after the onset of perturbations, was relatively unchanged in latency or amplitude compared to control conditions (P and P/AE). However, longer latency postural responses were modulated to aid in the reaching movements during forward perturbations but not during backward perturbations. Our results suggest that the nervous system prioritizes the maintenance of a stable postural base during reaching, and that later components of the postural responses can be modulated to ensure the performance of the voluntary task. PMID:20035321

Dissociative Global and Local Task-Switching Costs Across Younger Adults, Middle-Aged Adults, Older Adults, and Very Mild Alzheimer Disease Individuals

PubMed Central

Huff, Mark J.; Balota, David A.; Minear, Meredith; Aschenbrenner, Andrew J.; Duchek, Janet M.

2015-01-01

A task-switching paradigm was used to examine differences in attentional control across younger adults, middle-aged adults, healthy older adults, and individuals classified in the earliest detectable stage of Alzheimer's disease (AD). A large sample of participants (570) completed a switching task in which participants were cued to classify the letter (consonant/vowel) or number (odd/even) task-set dimension of a bivalent stimulus (e.g., A 14), respectively. A Pure block consisting of single-task trials and a Switch block consisting of nonswitch and switch trials were completed. Local (switch vs. nonswitch trials) and global (nonswitch vs. pure trials) costs in mean error rates, mean response latencies, underlying reaction time distributions, along with stimulus-response congruency effects were computed. Local costs in errors were group invariant, but global costs in errors systematically increased as a function of age and AD. Response latencies yielded a strong dissociation: Local costs decreased across groups whereas global costs increased across groups. Vincentile distribution analyses revealed that the dissociation of local and global costs primarily occurred in the slowest response latencies. Stimulus-response congruency effects within the Switch block were particularly robust in accuracy in the very mild AD group. We argue that the results are consistent with the notion that the impaired groups show a reduced local cost because the task sets are not as well tuned, and hence produce minimal cost on switch trials. In contrast, global costs increase because of the additional burden on working memory of maintaining two task sets. PMID:26652720

Functional brain development in growth-restricted and constitutionally small fetuses: a fetal magnetoencephalography case-control study.

PubMed

Morin, E C; Schleger, F; Preissl, H; Braendle, J; Eswaran, H; Abele, H; Brucker, S; Kiefer-Schmidt, I

2015-08-01

Fetal magnetoencephalography records fetal brain activity non-invasively. Delayed brain responses were reported for fetuses weighing below the tenth percentile. To investigate whether this delay indicates delayed brain maturation resulting from placental insufficiency, this study distinguished two groups of fetuses below the tenth percentile: growth-restricted fetuses with abnormal umbilical artery Doppler velocity (IUGR) and constitutionally small-for-gestational-age fetuses with normal umbilical artery Doppler findings (SGA) were compared with fetuses of adequate weight for gestational age (AGA), matched for age and behavioural state. A case-control study of matched pairs. Fetal magnetoencephalography-Center at the University Hospital of Tuebingen. Fourteen IUGR fetuses and 23 SGA fetuses were matched for gestational age and fetal behavioural state with 37 healthy, normal-sized fetuses. A 156-channel fetal magentoencephalography system was used to record fetal brain activity. Light flashes as visual stimulation were applied to the fetus. The Student's t-test for paired groups was performed. Latency of fetal visual evoked magnetic responses (VER). The IUGR fetuses showed delayed VERs compared with controls (IUGR, 233.1 ms; controls, 184.6 ms; P = 0.032). SGA fetuses had similar evoked response latencies compared with controls (SGA, 216.1 ms; controls, 219.9 ms; P = 0.828). Behavioural states were similarly distributed. Visual evoked responses are delayed in IUGR fetuses, but not in SGA. Fetal behavioural state as an influencing factor of brain response latency was accounted for in the comparison. This reinforces that delayed brain maturation is the result of placental insufficiency. © 2015 Royal College of Obstetricians and Gynaecologists.

Sleep-wake time perception varies by direct or indirect query.

PubMed

Alameddine, Y; Ellenbogen, J M; Bianchi, M T

2015-01-15

The diagnosis of insomnia rests on self-report of difficulty initiating or maintaining sleep. However, subjective reports may be unreliable, and possibly may vary by the method of inquiry. We investigated this possibility by comparing within-individual response to direct versus indirect time queries after overnight polysomnography. We obtained self-reported sleep-wake times via morning questionnaires in 879 consecutive adult diagnostic polysomnograms. Responses were compared within subjects (direct versus indirect query) and across groups defined by apnea-hypopnea index and by self-reported insomnia symptoms in pre-sleep questionnaires. Direct queries required a time duration response, while indirect queries required clock times from which we calculated time durations. Direct and indirect queries of sleep latency were the same in only 41% of cases, and total sleep time queries matched in only 5.4%. For both latency and total sleep, the most common discrepancy involved the indirect value being larger than the direct response. The discrepancy between direct and indirect queries was not related to objective sleep metrics. The degree of discrepancy was not related to the presence of insomnia symptoms, although patients reporting insomnia symptoms showed underestimation of total sleep duration by direct response. Self-reported sleep latency and total sleep time are often internally inconsistent when comparing direct and indirect survey queries of each measure. These discrepancies represent substantive challenges to effective clinical practice, particularly when diagnosis and management depends on self-reported sleep patterns, as with insomnia. Although self-reported sleep-wake times remains fundamental to clinical practice, objective measures provide clinically relevant adjunctive information. © 2015 American Academy of Sleep Medicine.

Deconvolution of magnetic acoustic change complex (mACC).

PubMed

Bardy, Fabrice; McMahon, Catherine M; Yau, Shu Hui; Johnson, Blake W

2014-11-01

The aim of this study was to design a novel experimental approach to investigate the morphological characteristics of auditory cortical responses elicited by rapidly changing synthesized speech sounds. Six sound-evoked magnetoencephalographic (MEG) responses were measured to a synthesized train of speech sounds using the vowels /e/ and /u/ in 17 normal hearing young adults. Responses were measured to: (i) the onset of the speech train, (ii) an F0 increment; (iii) an F0 decrement; (iv) an F2 decrement; (v) an F2 increment; and (vi) the offset of the speech train using short (jittered around 135ms) and long (1500ms) stimulus onset asynchronies (SOAs). The least squares (LS) deconvolution technique was used to disentangle the overlapping MEG responses in the short SOA condition only. Comparison between the morphology of the recovered cortical responses in the short and long SOAs conditions showed high similarity, suggesting that the LS deconvolution technique was successful in disentangling the MEG waveforms. Waveform latencies and amplitudes were different for the two SOAs conditions and were influenced by the spectro-temporal properties of the sound sequence. The magnetic acoustic change complex (mACC) for the short SOA condition showed significantly lower amplitudes and shorter latencies compared to the long SOA condition. The F0 transition showed a larger reduction in amplitude from long to short SOA compared to the F2 transition. Lateralization of the cortical responses were observed under some stimulus conditions and appeared to be associated with the spectro-temporal properties of the acoustic stimulus. The LS deconvolution technique provides a new tool to study the properties of the auditory cortical response to rapidly changing sound stimuli. The presence of the cortical auditory evoked responses for rapid transition of synthesized speech stimuli suggests that the temporal code is preserved at the level of the auditory cortex. Further, the reduced amplitudes and shorter latencies might reflect intrinsic properties of the cortical neurons to rapidly presented sounds. This is the first demonstration of the separation of overlapping cortical responses to rapidly changing speech sounds and offers a potential new biomarker of discrimination of rapid transition of sound. Crown Copyright © 2014. Published by Elsevier Ireland Ltd. All rights reserved.

Ontogeny of vestibular compound action potentials in the domestic chicken

NASA Technical Reports Server (NTRS)

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

2000-01-01

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

Ontogeny of Vestibular Compound Action Potentials in the Domestic Chicken

PubMed Central

M. Jones, Sherri

2000-01-01

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

Input and output compensation for the cochlear traveling wave delay in wide-band ABR recordings: implications for small acoustic tumor detection.

PubMed

Don, Manuel; Elberling, Claus; Maloff, Erin

2009-02-01

The Stacked ABR (auditory brainstem response) attempts at the output of the auditory periphery to compensate for the temporal dispersion of neural activation caused by the cochlear traveling wave in response to click stimulation. Compensation can also be made at the input by using a chirp stimulus. It has been demonstrated that the Stacked ABR is sensitive to small tumors that are often missed by standard ABR latency measures. Because a chirp stimulus requires only a single data acquisition run whereas the Stacked ABR requires six, we try to evaluate some indirect evidence justifying the use of a chirp for small tumor detection. We compared the sensitivity and specificity of different Stacked ABRs formed by aligning the derived-band ABRs according to (1) the individual's peak latencies, (2) the group mean latencies, and (3) the modeled latencies used to develop a chirp. For tumor detection with a chosen sensitivity of 95%, a relatively high specificity of 85% may be achieved with a chirp. It appears worthwhile to explore the actual use of a chirp because significantly shorter test and analysis times might be possible.

Directional Selectivity for FM Sweeps in the Suprageniculate Nucleus of the Mustached Bat Medial Geniculate Body

PubMed Central

O’NEILL, WILLIAM E.; BRIMIJOIN, W. OWEN

2014-01-01

Mustached bats emit echolocation and communication calls containing both constant frequency (CF) and frequency-modulated (FM) components. Previously we found that 86% of neurons in the ventral division of the external nucleus of the inferior colliculus (ICXv) were directionally selective for linear FM sweeps and that selectivity was dependent on sweep rate. The ICXv projects to the suprageniculate nucleus (Sg) of the medial geniculate body. In this study, we isolated 37 single units in the Sg and measured their responses to best excitatory frequency (BEF) tones and linear 12-kHz upward and downward FM sweeps centered on the BEF. Sweeps were presented at durations of 30, 12, and 4 ms, yielding modulation rates of 400, 1,000, and 3,000 kHz/s. Spike count versus level functions were obtained at each modulation rate and compared with BEF controls. Sg units responded well to both tones and FM sweeps. BEFs clustered at 58 kHz, corresponding to the dominant CF component of the sonar signal. Spike count functions for both tones and sweeps were predominantly non-monotonic. FM directional selectivity was significant in 53–78% of the units, depending on modulation rate and level. Units were classified as up-selective (52%), down-selective (24%), or bi-directional (non-selective, 16%); a few units (8%) showed preferences that were either rate- or level-dependent. Most units showed consistent directional preferences at all SPLs and modulation rates tested, but typically showed stronger selectivity at lower sweep rates. Directional preferences were attributable to suppression of activity by sweeps in the non-preferred direction (~80% of units) and/or facilitation by sweeps in the preferred direction (~20–30%). Latencies for BEF tones ranged from 4.9 to 25.7 ms. Latencies for FM sweeps typically varied linearly with sweep duration. Most FM latency-duration functions had slopes ranging from 0.4 to 0.6, suggesting that the responses were triggered by the BEF. Latencies for BEF tones and FM sweeps were significantly correlated in most Sg units, i.e., the response to FM was temporally related to the occurrence of the BEF in the FM sweep. FM latency declined relative to BEF latency as modulation rate increased, suggesting that at higher rates response is triggered by frequencies in the sweep preceding the BEF. We conclude that Sg and ICXv units have similar, though not identical, response properties. Sg units are predominantly upsweep selective and could respond to either or both the CF and FM components in biosonar signals in a number of echolocation scenarios, as well as to a variety of communication sounds. PMID:12091543

Marek's Disease Virus-Induced Immunosuppression: Array Analysis of Chicken Immune Response Gene Expression Profiling

USDA-ARS?s Scientific Manuscript database

Marek’s disease (MD) is a lymphoproliferative disease of chickens induced by a highly cell-associated oncogenic alpha-herpesvirus, Marek’s disease virus (MDV). MDV replicates in chicken lymphocytes and establishes a latency infection within CD4+ T cells. Host-virus interaction, immune responses to...

The Middle Latency Response (MLR) and Steady State Evoked Potential (SSEP) in Neonates.

DTIC Science & Technology

1985-05-01

diagnostic audiologic information will enhance habilitation efforts in prescribing hearing aids and designing appropriate language intervention strategies...auditory evoked brain stem response. A study of patients with sensory hearing loss. SCANDINAVIAN AUDIOLOGY 8: 67-70, 1979. Page 165 "- FILMED 10-85 DTIC * 4 N . . -. N

Impact of mild traumatic brain injury on auditory brain stem dysfunction in mouse model.

PubMed

Amanipour, Reza M; Frisina, Robert D; Cresoe, Samantha A; Parsons, Teresa J; Xiaoxia Zhu; Borlongan, Cesario V; Walton, Joseph P

2016-08-01

The auditory brainstem response (ABR) is an electrophysiological test that examines the functionality of the auditory nerve and brainstem. Traumatic brain injury (TBI) can be detected if prolonged peak latency is observed in ABR measurements, since latency measures the neural conduction time in the brainstem, and an increase in latency can be a sign of pathological lesion at the auditory brainstem level. The ABR is elicited by brief sounds that can be used to measure hearing sensitivity as well as temporal processing. Reduction in peak amplitudes and increases in latency are indicative of dysfunction in the auditory nerve and/or central auditory pathways. In this study we used sixteen young adult mice that were divided into two groups: sham and mild traumatic brain injury (mTBI), with ABR measurements obtained prior to, and at 2, 6, and 14 weeks after injury. Abnormal ABRs were observed for the nine TBI cases as early as two weeks after injury and the deficits lasted for fourteen weeks after injury. Results indicated a significant reduction in the Peak 1 (P1) and Peak 4 (P4) amplitudes to the first noise burst, as well as an increase in latency response for P1 and P4 following mTBI. These results are the first to demonstrate auditory sound processing deficits in a rodent model of mild TBI.

Auditory Magnetic Mismatch Field Latency: A Biomarker for Language Impairment in Autism

PubMed Central

Roberts, Timothy P.L.; Cannon, Katelyn M.; Tavabi, Kambiz; Blaskey, Lisa; Khan, Sarah Y.; Monroe, Justin F.; Qasmieh, Saba; Levy, Susan E.; Edgar, J. Christopher

2011-01-01

Background Auditory processing abnormalities are frequently observed in Autism Spectrum Disorders (ASD), and these abnormalities may have sequelae in terms of clinical language impairment (LI). The present study assessed associations between language impairment and the amplitude and latency of the superior temporal gyrus magnetic mismatch field (MMF) in response to changes in an auditory stream of tones or vowels. Methods 51 children with ASD and 27 neurotypical controls, all aged 6-15 years, underwent neuropsychological evaluation, including tests of language function, as well as magnetoencephalographic (MEG) recording during presentation of tones and vowels. The MMF was identified in the difference waveform obtained from subtraction of responses to standard stimuli from deviant stimuli. Results MMF latency was significantly prolonged (p<0.001) in children with ASD compared to neurotypical controls. Furthermore, this delay was most pronounced (∼50ms) in children with concomitant LI, with significant differences in latency between children with ASD with LI and those without (p<0.01). Receiver operator characteristic analysis indicated a sensitivity of 82.4% and specificity of 71.2% for diagnosing LI based on MMF latency. Conclusion Neural correlates of auditory change detection (the MMF) are significantly delayed in children with ASD, and especially those with concomitant LI suggesting both a neurobiological basis for LI as well as a clinical biomarker for LI in ASD. PMID:21392733

Time Counts! Some Comments on System Latency in Head-Referenced Displays

NASA Technical Reports Server (NTRS)

Ellis, Stephen R.; Adelstein, Bernard D.

2013-01-01

System response latency is a prominent characteristic of human-computer interaction. Laggy systems are; however, not simply annoying but substantially reduce user productivity. The impact of latency on head referenced display systems, particularly head-mounted systems, is especially disturbing since not only can it interfere with dynamic registration in augmented reality displays but it also can in some cases indirectly contribute to motion sickness. We will summarize several experiments using standard psychophysical discrimination techniques that suggest what system latencies will be required to achieve perceptual stability for spatially referenced computer-generated imagery. In conclusion I will speculate about other system performance characteristics that I would hope to have for a dream augmented reality system.

Impaired response selection in schizophrenia: Evidence from the P3 wave and the lateralized readiness potential

PubMed Central

Luck, Steven J.; Kappenman, Emily S.; Fuller, Rebecca L.; Robinson, Benjamin; Summerfelt, Ann; Gold, James M.

2008-01-01

Reaction times (RTs) are substantially prolonged in schizophrenia patients, but the latency of the P3 component is not. This suggests that the RT slowing arises from impairments in a late stage of processing. To test this hypothesis, 20 schizophrenia patients and 20 control subjects were tested in a visual oddball paradigm that was modified to allow measurement of the lateralized readiness potential (LRP), an index of stimulus-response translation processes. Difference waves were used to isolate the LRP and the P3 wave. Patients and control subjects exhibited virtually identical P3 difference waves, whereas the LRP difference wave was reduced in amplitude and delayed in latency in the patients. These results indicate that, at least in simple tasks, the delayed RTs observed in schizophrenia are primarily a consequence of impairments in the response selection and preparation processes that follow perception and categorization. PMID:19386044

Event-related potentials to visual, auditory, and bimodal (combined auditory-visual) stimuli.

PubMed

Isoğlu-Alkaç, Ummühan; Kedzior, Karina; Keskindemirci, Gonca; Ermutlu, Numan; Karamursel, Sacit

2007-02-01

The purpose of this study was to investigate the response properties of event related potentials to unimodal and bimodal stimulations. The amplitudes of N1 and P2 were larger during bimodal evoked potentials (BEPs) than auditory evoked potentials (AEPs) in the anterior sites and the amplitudes of P1 were larger during BEPs than VEPs especially at the parieto-occipital locations. Responses to bimodal stimulation had longer latencies than responses to unimodal stimulation. The N1 and P2 components were larger in amplitude and longer in latency during the bimodal paradigm and predominantly occurred at the anterior sites. Therefore, the current bimodal paradigm can be used to investigate the involvement and location of specific neural generators that contribute to higher processing of sensory information. Moreover, this paradigm may be a useful tool to investigate the level of sensory dysfunctions in clinical samples.

Cervical Vestibular-Evoked Myogenic Potentials: Norms and Protocols

PubMed Central

Isaradisaikul, Suwicha; Navacharoen, Niramon; Hanprasertpong, Charuk; Kangsanarak, Jaran

2012-01-01

Vestibular-evoked myogenic potential (VEMP) testing is a vestibular function test used for evaluating saccular and inferior vestibular nerve function. Parameters of VEMP testing include VEMP threshold, latencies of p1 and n1, and p1-n1 interamplitude. Less commonly used parameters were p1-n1 interlatency, interaural difference of p1 and n1 latency, and interaural amplitude difference (IAD) ratio. This paper recommends using air-conducted 500 Hz tone burst auditory stimulation presented monoaurally via an inserted ear phone while the subject is turning his head to the contralateral side in the sitting position and recording the responses from the ipsilateral sternocleidomastoid muscle. Normative values of VEMP responses in 50 normal audiovestibular volunteers were presented. VEMP testing protocols and normative values in other literature were reviewed and compared. The study is beneficial to clinicians as a reference guide to set up VEMP testing and interpretation of the VEMP responses. PMID:22577386

Differential responses of primary auditory cortex in autistic spectrum disorder with auditory hypersensitivity.

PubMed

Matsuzaki, Junko; Kagitani-Shimono, Kuriko; Goto, Tetsu; Sanefuji, Wakako; Yamamoto, Tomoka; Sakai, Saeko; Uchida, Hiroyuki; Hirata, Masayuki; Mohri, Ikuko; Yorifuji, Shiro; Taniike, Masako

2012-01-25

The aim of this study was to investigate the differential responses of the primary auditory cortex to auditory stimuli in autistic spectrum disorder with or without auditory hypersensitivity. Auditory-evoked field values were obtained from 18 boys (nine with and nine without auditory hypersensitivity) with autistic spectrum disorder and 12 age-matched controls. Autistic disorder with hypersensitivity showed significantly more delayed M50/M100 peak latencies than autistic disorder without hypersensitivity or the control. M50 dipole moments in the hypersensitivity group were larger than those in the other two groups [corrected]. M50/M100 peak latencies were correlated with the severity of auditory hypersensitivity; furthermore, severe hypersensitivity induced more behavioral problems. This study indicates auditory hypersensitivity in autistic spectrum disorder as a characteristic response of the primary auditory cortex, possibly resulting from neurological immaturity or functional abnormalities in it. © 2012 Wolters Kluwer Health | Lippincott Williams & Wilkins.

Vestibular evoked myogenic potential (VEMP) testing: normative threshold response curves and effects of age.

PubMed

Janky, Kristen L; Shepard, Neil

2009-09-01

Vestibular evoked myogenic potential (VEMP) testing has gained increased interest in the diagnosis of a variety of vestibular etiologies. P13/N23 latency, amplitude and threshold response curves have been used to compare pathologic groups to normal controls. Appropriate characterization of these etiologies requires normative data across the frequency spectrum and age range. The objective of the current study was to test the hypothesis that significant changes in VEMP responses occur as a function of increased age across all test stimuli as well as characterize the VEMP threshold response curve across age. This project incorporated a prospective study design using a sample of convenience. Openly recruited subjects were assigned to groups according to age. Forty-six normal controls ranging between 20 and 76 years of age participated in the study. Participants were separated by decade into five age categories from 20 to 60 plus years. Normal participants were characterized by having normal hearing sensitivity, no history of neurologic or balance/dizziness involvement, and negative results on a direct office vestibular examination. VEMP responses were measured at threshold to click and 250, 500, 750, and 1000 Hz tone burst stimuli and at a suprathreshold level to 500 Hz toneburst stimuli at123 dB SPL. A mixed group factorial ANOVA (analysis of variance) and linear regression were performed to examine the effects of VEMP characteristics on age. There were no significant differences between ears for any of the test parameters. There were no significant differences between age groups for n23 latency or amplitude in response to any of the stimuli. Significant mean differences did exist between age groups for p13 latency (250, 750, and 1000 Hz) and threshold (500 and 750 Hz). Age was significantly correlated with VEMP parameters. VEMP threshold was positively correlated (250, 500, 750, 1000 Hz); and amplitude was negatively correlated (500 Hz maximum). The threshold response curves revealed best frequency tuning at 500 Hz with the highest thresholds in response to click stimuli. However, this best frequency tuning dissipated with increased age. VEMP response rates also decreased with increased age. We have demonstrated that minor differences in VEMP responses occur with age. Given the reduced response rates and flattened frequency tuning curve for individuals over the age of 60, frequency tuning curves may not be a good diagnostic indicator for this age group.

Precision grip responses to unexpected rotational perturbations scale with axis of rotation.

PubMed

De Gregorio, Michael; Santos, Veronica J

2013-04-05

It has been established that rapid, pulse-like increases in precision grip forces ("catch-up responses") are elicited by unexpected translational perturbations and that response latency and strength scale according to the direction of linear slip relative to the hand as well as gravity. To determine if catch-up responses are elicited by unexpected rotational perturbations and are strength-, axis-, and/or direction-dependent, we imposed step torque loads about each of two axes which were defined relative to the subject's hand: the distal-proximal axis away from and towards the subject's palm, and the grip axis which connects the two fingertips. Precision grip responses were dominated initially by passive mechanics and then by active, unimodal catch-up responses. First dorsal interosseous activity, marking the start of the catch-up response, began 71-89 ms after the onset of perturbation. The onset latency, shape, and duration (217-231 ms) of the catch-up response were not affected by the axis, direction, or magnitude of the rotational perturbation, while strength was scaled by axis of rotation and slip conditions. Rotations about the grip axis that tilted the object away from the palm and induced rotational slip elicited stronger catch-up responses than rotations about the distal-proximal axis that twisted the object between the digits. To our knowledge, this study is the first to investigate grip responses to unexpected torque loads and to show characteristic, yet axis-dependent, catch-up responses for conditions other than pure linear slip. Copyright © 2013 Elsevier Ltd. All rights reserved.

Response latencies in auditory sentence comprehension: effects of linguistic versus perceptual challenge.

PubMed

Tun, Patricia A; Benichov, Jonathan; Wingfield, Arthur

2010-09-01

Older adults with good hearing and with mild-to-moderate hearing loss were tested for comprehension of spoken sentences that required perceptual effort (hearing speech at lower sound levels), and two degrees of cognitive load (sentences with simpler or more complex syntax). Although comprehension accuracy was equivalent for both participant groups and for young adults with good hearing, hearing loss was associated with longer response latencies to the correct comprehension judgments, especially for complex sentences heard at relatively low amplitudes. These findings demonstrate the need to take into account both sensory and cognitive demands of speech materials in older adults' language comprehension. (c) 2010 APA, all rights reserved.

Inhibition deficit in the spatial tendency of the response in multiple-domain amnestic mild cognitive impairment. An event-related potential study

PubMed Central

Cespón, Jesús; Galdo-Álvarez, Santiago; Díaz, Fernando

2015-01-01

Longitudinal studies have shown that a high percentage of people with amnestic mild cognitive impairment (MCI) develop Alzheimer’s disease (AD). Prodromal AD is known to involve deficits in executive control processes. In the present study, we examined such deficits by recording EEG in 13 single-domain amnestic MCI (sdaMCI), 12 multiple-domain amnestic MCI (mdaMCI) and 18 healthy elderly (control group, CG) participants while they performed a Simon task. The Simon task demands deployment of executive processes because participants have to respond to non-spatial features of a lateralized stimulus and inhibit the more automatic spatial tendency of the response. We specifically focused on the negativity central contralateral (N2cc), an event-related potential (ERP) component related to brain activity that prevents the cross-talk between direction of spatial attention and manual response preparation. The reaction time (RT) was not significantly different among the three groups of participants. The percentage of errors (PE) was higher in mdaMCI than in CG and sdaMCI participants. In addition, N2cc latency was delayed in mdaMCI (i.e., delayed implementation of mechanisms for controlling the spatial tendency of the response). The N2cc latency clearly distinguished among mdaMCI and CG/sdaMCI participants (area under curve: 0.91). Longer N2cc was therefore associated with executive control deficits, which suggests that N2cc latency is a correlate of mdaMCI. PMID:25999853

Acute ethanol effects on neural encoding of reward size and delay in the nucleus accumbens

PubMed Central

Gutman, Andrea L.

2016-01-01

Acute ethanol administration can cause impulsivity, resulting in increased preference for immediately available rewards over delayed but more valuable alternatives. The manner in which reward size and delay are represented in neural firing is not fully understood, and very little is known about ethanol effects on this encoding. To address this issue, we used in vivo electrophysiology to characterize neural firing in the core of the nucleus accumbens (NAcc) in rats responding for rewards that varied in size or delay after vehicle or ethanol administration. The NAcc is a central element in the circuit that governs decision-making and importantly, promotes choice of delayed rewards. We found that NAcc firing in response to reward-predictive cues encoded anticipated reward value after vehicle administration, but ethanol administration disrupted this encoding, resulting in a loss of discrimination between immediate and delayed rewards in cue-evoked neural responses. In addition, NAcc firing occurring at the time of the operant response (lever pressing) was inversely correlated with behavioral response latency, such that increased firing rates were associated with decreased latencies to lever press. Ethanol administration selectively attenuated this lever press-evoked firing when delayed but not immediate rewards were expected. These effects on neural firing were accompanied by increased behavioral latencies to respond for delayed rewards. Our results suggest that ethanol effects on NAcc cue- and lever press-evoked encoding may contribute to ethanol-induced impulsivity. PMID:27169507

A computerized Stroop task to assess cancer-related cognitive biases.

PubMed

DiBonaventura, Marco DaCosta; Erblich, Joel; Sloan, Richard P; Bovbjerg, Dana H

2010-01-01

Biases in processing information related to sources of stress have widely been demonstrated with the use of Stroop emotional color word tasks. One study reported such biases among women with histories of breast cancer in a first-degree relative (FH+) who were given a Stroop cancer word task. This study aimed to replicate and extend these findings with a computerized version of the task. Response latencies and errors were recorded during administration of the task to FH+ and FH- women. A cancer list and 5 comparison lists were administered. Results indicated that FH+ women exhibited longer response latencies for cancer words than did FH- women (p < 0.04), providing further support for cognitive biases in FH+ women. Confirming the psychometric properties of the task, lists exhibited high reliability for both latency (alphas 0.96-0.98) and error rate (alphas 0.61-0.79). In sum, results support the favorable psychometrics and predictive validity of the Stroop cancer word task.

Sound duration as a perceptual cue influencing vocal behavior of male bullfrogs

NASA Astrophysics Data System (ADS)

Simmons, Andrea M.

2002-05-01

Female frogs of several species use the temporal cue of sound duration to aid in mate choice. Little is known, however, about the sensitivity of male frogs to this cue. Male bullfrogs emit a complex advertisement call to attract females for mating, and to announce territory occupation to other males. In two experiments, the sensitivity of vocalizing male bullfrogs to field playbacks of advertisement calls differing in duration was examined. The number and latency of evoked vocal responses to the stimuli was used as a measure of perception. Males responded with fewer calls, at longer latencies, to stimuli shorter in duration than the standard signal (with a duration at the mean value for the species). Males preferred stimuli longer in duration than the standard signal, responding with more calls at shorter latencies. They did not, however, significantly lengthen their own calls in response to playbacks of long duration signals. This preference for ``supernormal'' stimuli may be an important factor mediating the evolution of communication signals. [Work supported by NIH.

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

PubMed

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

2014-03-01

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. 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. 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. The findings suggest that children with phonological disorders have impaired auditory brainstem and cortical region pathways that may benefit from speech therapy.

The Electrophysiology of Electric Organs of Marine Electric Fishes

PubMed Central

Bennett, M. V. L.; Wurzel, M.; Grundfest, H.

1961-01-01

Single electroplaques of Torpedo nobiliana have been studied with microelectrode recording. Direct evidence is presented that the only electrogenically reactive membrane of the cells is on the innervated surface and that this membrane is electrically inexcitable. Responses are not evoked by depolarizing currents applied to this membrane, but only by stimulating the innervating nerve fibers. The responses arise after a latency of 1 to 3 msec. This latency is not affected by large depolarizing or hyperpolarizing changes in membrane potential. Various properties that have been theoretically associated with electrically inexcitable responses have been also demonstrated to occur in the electroplaques. The neurally evoked response is not propagated actively in the membrane and may have different amplitudes and forms in closely adjacent regions. The maximal responses frequently are slightly larger than the recorded resting potential but the apparent small overshoot may be due to difficulty in recording the full resting potential. The responses are subject to electrochemical gradation and appear inverted in sign on applying strong outward currents across the innervated membrane. This membrane is cholinoceptive and shows marked desensitization. The membrane of the uninnervated surface has a very low resistance, a factor that aids maximum output of current during the discharge of the electric organ. PMID:19873534

Concurrent deployment of visual attention and response selection bottleneck in a dual-task: Electrophysiological and behavioural evidence.

PubMed

Reimer, Christina B; Strobach, Tilo; Schubert, Torsten

2017-12-01

Visual attention and response selection are limited in capacity. Here, we investigated whether visual attention requires the same bottleneck mechanism as response selection in a dual-task of the psychological refractory period (PRP) paradigm. The dual-task consisted of an auditory two-choice discrimination Task 1 and a conjunction search Task 2, which were presented at variable temporal intervals (stimulus onset asynchrony, SOA). In conjunction search, visual attention is required to select items and to bind their features resulting in a serial search process around the items in the search display (i.e., set size). We measured the reaction time of the visual search task (RT2) and the N2pc, an event-related potential (ERP), which reflects lateralized visual attention processes. If the response selection processes in Task 1 influence the visual attention processes in Task 2, N2pc latency and amplitude would be delayed and attenuated at short SOA compared to long SOA. The results, however, showed that latency and amplitude were independent of SOA, indicating that visual attention was concurrently deployed to response selection. Moreover, the RT2 analysis revealed an underadditive interaction of SOA and set size. We concluded that visual attention does not require the same bottleneck mechanism as response selection in dual-tasks.

Vocalization-Induced Enhancement of the Auditory Cortex Responsiveness during Voice F0 Feedback Perturbation

PubMed Central

Behroozmand, Roozbeh; Karvelis, Laura; Liu, Hanjun; Larson, Charles R.

2009-01-01

Objective The present study investigated whether self-vocalization enhances auditory neural responsiveness to voice pitch feedback perturbation and how this vocalization-induced neural modulation can be affected by the extent of the feedback deviation. Method Event related potentials (ERPs) were recorded in 15 subjects in response to +100, +200 and +500 cents pitch-shifted voice auditory feedback during active vocalization and passive listening to the playback of the self-produced vocalizations. Result The amplitude of the evoked P1 (latency: 73.51 ms) and P2 (latency: 199.55 ms) ERP components in response to feedback perturbation were significantly larger during vocalization than listening. The difference between P2 peak amplitudes during vocalization vs. listening was shown to be significantly larger for +100 than +500 cents stimulus. Conclusion Results indicate that the human auditory cortex is more responsive to voice F0 feedback perturbations during vocalization than passive listening. Greater vocalization-induced enhancement of the auditory responsiveness to smaller feedback perturbations may imply that the audio-vocal system detects and corrects for errors in vocal production that closely match the expected vocal output. Significance Findings of this study support previous suggestions regarding the enhanced auditory sensitivity to feedback alterations during self-vocalization, which may serve the purpose of feedback-based monitoring of one’s voice. PMID:19520602

Choice as a dependent measure in autoshaping: sensitivity to frequency and duration of food presentation.

PubMed Central

Picker, M; Poling, A

1982-01-01

Previous investigations have shown that rate, latency, and percentage of trials with at least one response are somewhat insensitive measures of the strength of autoshaped responding. In the present studies, these measures were contrasted with the allocation of responding during simultaneous choice tests, a measure of response strength frequently used in operant paradigms. In two experiments, nine pigeons were exposed to a forward pairing autoshaping procedure. Training sessions consisted of the successive presentation of three stimuli, each followed by food on either 100%, 50%, or 0% of the trials. Choice testing involved the simultaneous presentation of the three stimuli. In Experiment I, all pigeons consistently directed their initial choice responses and the majority of subsequent responses to the stimulus always followed by food, despite the fact that during training sessions the response rates of most birds were highest in the presence of the stimulus followed by food on 50% of the trials. In Experiment II, rate, latency, and percentage of trials with at least one response did not change appreciably as a function of duration of feeder presentations. However, choice responding was lawfully affected by duration of feeder presentations. These data suggest that choice is perhaps a more sensitive measure of the strength of autoshaped responding than other, more commonly employed, indices. PMID:7097152

[Effects of intermittent hypoxia on the responses of genioglossus motor cortex to transcranial magnetic stimulation in rats].

PubMed

Li, Ting; Wang, Wei; Kong, De-lei; Su, Jiao; Kang, Jian

2012-04-01

To explore the influence of intermittent hypoxia on the responses of genioglossus motor cortex to transcranial magnetic stimulation. Male Sprague-Dawley rats were randomly divided into a control group and a chronic intermittent hypoxia group. Transcranial magnetic stimulation was applied in genioglossus motor cortex of the 2 groups. The responses of transcranial magnetic stimulation were recorded and analyzed by single factor analysis of variance. The anterolateral area provided an optimal motor evoked potential response to transcranial magnetic stimulation in the genioglossus motor cortex of the rats. Genioglossus motor evoked potential latency and amplitude were significantly modified by intermittent hypoxic exposure, with a significant decrease in latency (F = 3.294, P < 0.01) at the 1st day [(4.90 ± 0.54) ms] and the 14th day [(4.64 ± 1.71) ms], and an increase in amplitude (F = 1.905, P < 0.05) at the 1st day [(2.28 ± 0.57) mV] and the 7th day [(1.89 ± 0.20) mV]. Intermittent hypoxia could increase the transcranial magnetic stimulation response of genioglossus motor cortex in rats.

When orienting and anticipation dissociate--a case for scoring electrodermal responses in multiple latency windows in studies of human fear conditioning.

PubMed

Luck, Camilla C; Lipp, Ottmar V

2016-02-01

Electrodermal activity in studies of human fear conditioning is often scored by distinguishing two electrodermal responses occurring during the conditional stimulus-unconditional stimulus interval. These responses, known as first interval responding (FIR) and second interval responding (SIR), are reported to be differentially sensitive to the effects of orienting and anticipation. Recently, the FIR/SIR scoring convention has been questioned, with some arguing in favor of scoring a single response within the entire conditional stimulus-unconditional stimulus interval (entire interval responding, EIR). EIR can be advantageous in practical terms but may fail to capture experimental effects when manipulations produce dissociations between orienting and anticipation. As an illustration, we rescored the data reported by Luck and Lipp (2015b) using both FIR/SIR and EIR scoring techniques and provide evidence that the EIR scoring technique fails to detect the effects of instructed extinction, an experimental manipulation which produces a dissociation between orienting and anticipation. Thus, using a technique that scores electrodermal response indices of fear conditioning in multiple latency windows is recommended. Copyright © 2015 Elsevier B.V. All rights reserved.

Multi-modal pain measurements in infants

PubMed Central

Worley, A.; Fabrizi, L.; Boyd, S.; Slater, R.

2012-01-01

A non-invasive integrated method was developed to measure neural and behavioural responses to peripheral sensory and noxious stimulation in human infants. The introduction of a novel event-detection interface allows synchronous recording of: (i) muscle and central nervous system activity with surface electromyography (EMG), scalp electroencephalography (EEG) and near-infrared spectroscopy (NIRS); (ii) behavioural responses with video-recording and (iii) autonomic responses (heart rate, oxygen saturation, respiratory rate and cardiovascular activity) with electrocardiography (ECG) and pulse oximetry. The system can detect noxious heel lance and touch stimuli with precision (33 μs and 624 μs respectively) and accuracy (523 μs and 256 μs) and has 100% sensitivity and specificity for both types of stimulation. Its ability to detect response latencies accurately was demonstrated by a shift in latency of the vertex potential of 20.7 ± 15.7 ms (n = 6 infants), following touch of the heel and of the shoulder, reflecting the distance between the two sites. This integrated system has provided reliable and reproducible measurements of responses to sensory and noxious stimulation in human infants on more than 100 test occasions. PMID:22285660

Multi-modal pain measurements in infants.

PubMed

Worley, A; Fabrizi, L; Boyd, S; Slater, R

2012-04-15

A non-invasive integrated method was developed to measure neural and behavioural responses to peripheral sensory and noxious stimulation in human infants. The introduction of a novel event-detection interface allows synchronous recording of: (i) muscle and central nervous system activity with surface electromyography (EMG), scalp electroencephalography (EEG) and near-infrared spectroscopy (NIRS); (ii) behavioural responses with video-recording and (iii) autonomic responses (heart rate, oxygen saturation, respiratory rate and cardiovascular activity) with electrocardiography (ECG) and pulse oximetry. The system can detect noxious heel lance and touch stimuli with precision (33 μs and 624 μs respectively) and accuracy (523 μs and 256 μs) and has 100% sensitivity and specificity for both types of stimulation. Its ability to detect response latencies accurately was demonstrated by a shift in latency of the vertex potential of 20.7 ± 15.7 ms (n=6 infants), following touch of the heel and of the shoulder, reflecting the distance between the two sites. This integrated system has provided reliable and reproducible measurements of responses to sensory and noxious stimulation in human infants on more than 100 test occasions. Copyright © 2012 Elsevier B.V. All rights reserved.

Concussive convulsions: A YouTube video analysis.

PubMed

Tényi, Dalma; Gyimesi, Csilla; Horváth, Réka; Kovács, Norbert; Ábrahám, Hajnalka; Darnai, Gergely; Fogarasi, András; Büki, András; Janszky, József

2016-08-01

To analyze seizure-like motor phenomena immediately occurring after concussion (concussive convulsions). Twenty-five videos of concussive convulsions were obtained from YouTube as a result of numerous sports-related search terms. The videos were analyzed by four independent observers, documenting observations of the casualty, the head injury, motor symptoms of the concussive convulsions, the postictal period, and the outcome. Immediate responses included the fencing response, bear hug position, and bilateral leg extension. Fencing response was the most common. The side of the hit (p = 0.039) and the head turning (p = 0.0002) was ipsilateral to the extended arm. There was a tendency that if the blow had only a vertical component, the bear hug position appeared more frequently (p = 0.12). The motor symptom that appeared with latency of 6 ± 3 s was clonus, sometimes superimposed with tonic motor phenomena. Clonus was focal, focally evolving bilateral or bilateral, with a duration of 27 ± 19 s (5-72 s). Where lateralization of clonus could be determined, the side of clonus and the side of hit were contralateral (p = 0.039). Concussive convulsions consist of two phases. The short-latency first phase encompasses motor phenomena resembling neonatal reflexes and may be of brainstem origin. The long-latency second phase consists of clonus. We hypothesize that the motor symptoms of the long-latency phase are attributed to cortical structures; however, they are probably not epileptic in origin but rather a result of a transient cortical neuronal disturbance induced by mechanical forces. Wiley Periodicals, Inc. © 2016 International League Against Epilepsy.

Visually Evoked Potential Markers of Concussion History in Patients with Convergence Insufficiency

PubMed Central

Poltavski, Dmitri; Lederer, Paul; Cox, Laurie Kopko

2017-01-01

ABSTRACT Purpose We investigated whether differences in the pattern visual evoked potentials exist between patients with convergence insufficiency and those with convergence insufficiency and a history of concussion using stimuli designed to differentiate between magnocellular (transient) and parvocellular (sustained) neural pathways. Methods Sustained stimuli included 2-rev/s, 85% contrast checkerboard patterns of 1- and 2-degree check sizes, whereas transient stimuli comprised 4-rev/s, 10% contrast vertical sinusoidal gratings with column width of 0.25 and 0.50 cycles/degree. We tested two models: an a priori clinical model based on an assumption of at least a minimal (beyond instrumentation’s margin of error) 2-millisecond lag of transient response latencies behind sustained response latencies in concussed patients and a statistical model derived from the sample data. Results Both models discriminated between concussed and nonconcussed groups significantly above chance (with 76% and 86% accuracy, respectively). In the statistical model, patients with mean vertical sinusoidal grating response latencies greater than 119 milliseconds to 0.25-cycle/degree stimuli (or mean vertical sinusoidal latencies >113 milliseconds to 0.50-cycle/degree stimuli) and mean vertical sinusoidal grating amplitudes of less than 14.75 mV to 0.50-cycle/degree stimuli were classified as having had a history of concussion. The resultant receiver operating characteristic curve for this model had excellent discrimination between the concussed and nonconcussed (area under the curve = 0.857; P < .01) groups with sensitivity of 0.92 and specificity of 0.80. Conclusions The results suggest a promising electrophysiological approach to identifying individuals with convergence insufficiency and a history of concussion. PMID:28609417

Association Between Sex and Speech Auditory Brainstem Responses in Adults, and Relationship to Sex Hormone Levels.

PubMed

Liu, Jinfeng; Wang, Dan; Li, Xiaoting; Ningyu, Wang

2017-05-14

BACKGROUND The aim of this study was to investigate the association between sex and speech-ABR in adults, and its relationship to sex hormone levels. MATERIAL AND METHODS Speech-ABR were elicited with the consonant-vowel syllable (/da/) in a total of 35 adults. Reproductive hormone levels were also measured. RESULTS The transient response of the speech-ABR (waves V, A, and O) in females show a shorter latency (waves V, A and O) and a larger amplitude (waves V and A) than in males (P<0.05), except for the amplitude of peak O (P>0.05). The sustained response of females exhibited a larger amplitude (wave F, P<0.05) and a shorter latency (wave D, E, and F, P<0.05) than in males, except for the amplitude of peak D and E (P>0.05). The latencies of speech-ABR were positively correlated with testosterone level (P<0.05), and were negatively correlated with estradiol (E2) levels (P<0.05), except for wave E (P>0.05). The E2 showed a positive correlation with the absolute value of amplitude of the speech-ABR (P < 0.05). On the contrary, total testosterone showed a negative correlation with the absolute value of amplitude the speech-ABR (P<0.05), except for wave D and wave O (P>0.05). CONCLUSIONS Sex differences in speech-ABR are significant in adults. The latencies and amplitude of the speech-ABR waves were correlated with the E2 concentration and testosterone level. The sex hormones likely affect speech encoding in the brainstem.

The influence of cochlear spectral processing on the timing and amplitude of the speech-evoked auditory brain stem response

PubMed Central

Nuttall, Helen E.; Moore, David R.; Barry, Johanna G.; Krumbholz, Katrin

2015-01-01

The speech-evoked auditory brain stem response (speech ABR) is widely considered to provide an index of the quality of neural temporal encoding in the central auditory pathway. The aim of the present study was to evaluate the extent to which the speech ABR is shaped by spectral processing in the cochlea. High-pass noise masking was used to record speech ABRs from delimited octave-wide frequency bands between 0.5 and 8 kHz in normal-hearing young adults. The latency of the frequency-delimited responses decreased from the lowest to the highest frequency band by up to 3.6 ms. The observed frequency-latency function was compatible with model predictions based on wave V of the click ABR. The frequency-delimited speech ABR amplitude was largest in the 2- to 4-kHz frequency band and decreased toward both higher and lower frequency bands despite the predominance of low-frequency energy in the speech stimulus. We argue that the frequency dependence of speech ABR latency and amplitude results from the decrease in cochlear filter width with decreasing frequency. The results suggest that the amplitude and latency of the speech ABR may reflect interindividual differences in cochlear, as well as central, processing. The high-pass noise-masking technique provides a useful tool for differentiating between peripheral and central effects on the speech ABR. It can be used for further elucidating the neural basis of the perceptual speech deficits that have been associated with individual differences in speech ABR characteristics. PMID:25787954

Effect of stance width on multidirectional postural responses

NASA Technical Reports Server (NTRS)

Henry, S. M.; Fung, J.; Horak, F. B.; Peterson, B. W. (Principal Investigator)

2001-01-01

The effect of stance width on postural responses to 12 different directions of surface translations was examined. Postural responses were characterized by recording 11 lower limb and trunk muscles, body kinematics, and forces exerted under each foot of 7 healthy subjects while they were subjected to horizontal surface translations in 12 different, randomly presented directions. A quasi-static approach of force analysis was done, examining force integrals in three different epochs (background, passive, and active periods). The latency and amplitude of muscle responses were quantified for each direction, and muscle tuning curves were used to determine the spatial activation patterns for each muscle. The results demonstrate that the horizontal force constraint exerted at the ground was lessened in the wide, compared with narrow, stance for humans, a similar finding to that reported by Macpherson for cats. Despite more trunk displacement in narrow stance, there were no significant changes in body center of mass (CoM) displacement due to large changes in center of pressure (CoP), especially in response to lateral translations. Electromyographic (EMG) magnitude decreased for all directions in wide stance, particularly for the more proximal muscles, whereas latencies remained the same from narrow to wide stance. Equilibrium control in narrow stance was more of an active postural strategy that included regulating the loading/unloading of the limbs and the direction of horizontal force vectors. In wide stance, equilibrium control relied more on an increase in passive stiffness resulting from changes in limb geometry. The selective latency modulation of the proximal muscles with translation direction suggests that the trunk was being actively controlled in all directions. The similar EMG latencies for both narrow and wide stance, with modulation of only the muscle activation magnitude as stance width changed, suggest that the same postural synergy was only slightly modified for a change in stance width. Nevertheless, the magnitude of the trunk displacement, as well as of CoP displacement, was modified based on the degree of passive stiffness in the musculoskeletal system, which increased with stance width. The change from a more passive to an active horizontal force constraint, to larger EMG magnitudes especially in the trunk muscles and larger trunk and CoP excursions in narrow stance are consistent with a more effortful response for equilibrium control in narrow stance to perturbations in all directions.

Systemic administration of 8-OH-DPAT and eticlopride, but not SCH23390, alters loss-chasing behavior in the rat.

PubMed

Rogers, Robert D; Wong, Adeline; McKinnon, Chris; Winstanley, Catharine A

2013-05-01

Gambling to recover losses is a common gaming behavior. In a clinical context, however, this phenomenon mediates the relationship between diminished control over gambling and the adverse socioeconomic consequences of gambling problems. Modeling loss-chasing through analogous behaviors in rats could facilitate its pharmacological investigation as a potential therapeutic target. Here, rats were trained to make operant responses that produced both food rewards, and unpredictably, imminent time-out periods in which rewards would be unavailable. At these decision points, rats were offered choices between waiting for these time-out periods to elapse before resuming responding for rewards ('quit' responses), or selecting risky options with a 0.5 probability of avoiding the time-outs altogether and a 0.5 probability of time-out periods twice as long as signaled originally ('chase' responses). Chasing behavior, and the latencies to chase or quit, during sequences of unfavorable outcomes were tested following systemic administration of the 5-HT1A receptor agonist, 8-OH-DPAT, the D2 receptor antagonist, eticlopride, and the D1 receptor antagonist, SCH23390. 8-OH-DPAT and eticlopride significantly reduced the proportion of chase responses, and the mean number of consecutive chase responses, in a dose-dependent manner. 8-OH-DPAT also increased latencies to chase. Increasing doses of eticlopride first speeded, then slowed, latencies to quit while SCH23390 had no significant effects on any measure. Research is needed to identify the precise cognitive mechanisms mediating these kinds of risky choices in rats. However, our data provide the first experimental demonstration that 5-HT1A and D2, but not D1, receptor activity influence a behavioral analog of loss-chasing in rats.

Systemic Administration of 8-OH-DPAT and Eticlopride, but not SCH23390, Alters Loss-Chasing Behavior in the Rat

PubMed Central

Rogers, Robert D; Wong, Adeline; McKinnon, Chris; Winstanley, Catharine A

2013-01-01

Gambling to recover losses is a common gaming behavior. In a clinical context, however, this phenomenon mediates the relationship between diminished control over gambling and the adverse socioeconomic consequences of gambling problems. Modeling loss-chasing through analogous behaviors in rats could facilitate its pharmacological investigation as a potential therapeutic target. Here, rats were trained to make operant responses that produced both food rewards, and unpredictably, imminent time-out periods in which rewards would be unavailable. At these decision points, rats were offered choices between waiting for these time-out periods to elapse before resuming responding for rewards (‘quit' responses), or selecting risky options with a 0.5 probability of avoiding the time-outs altogether and a 0.5 probability of time-out periods twice as long as signaled originally (‘chase' responses). Chasing behavior, and the latencies to chase or quit, during sequences of unfavorable outcomes were tested following systemic administration of the 5-HT1A receptor agonist, 8-OH-DPAT, the D2 receptor antagonist, eticlopride, and the D1 receptor antagonist, SCH23390. 8-OH-DPAT and eticlopride significantly reduced the proportion of chase responses, and the mean number of consecutive chase responses, in a dose-dependent manner. 8-OH-DPAT also increased latencies to chase. Increasing doses of eticlopride first speeded, then slowed, latencies to quit while SCH23390 had no significant effects on any measure. Research is needed to identify the precise cognitive mechanisms mediating these kinds of risky choices in rats. However, our data provide the first experimental demonstration that 5-HT1A and D2, but not D1, receptor activity influence a behavioral analog of loss-chasing in rats. PMID:23303072

Multimodal communication, mismatched messages and the effects of turbidity on the antipredator behavior of the Barton Springs salamander, Eurycea sosorum.

PubMed

Zabierek, Kristina C; Gabor, Caitlin R

2016-09-01

Prey may use multiple sensory channels to detect predators, whose cues may differ in altered sensory environments, such as turbid conditions. Depending on the environment, prey may use cues in an additive/complementary manner or in a compensatory manner. First, to determine whether the purely aquatic Barton Springs salamander, Eurycea sosorum, show an antipredator response to visual cues, we examined their activity when exposed to either visual cues of a predatory fish (Lepomis cyanellus) or a non-predatory fish (Etheostoma lepidum). Salamanders decreased activity in response to predator visual cues only. Then, we examined the antipredator response of these salamanders to all matched and mismatched combinations of chemical and visual cues of the same predatory and non-predatory fish in clear and low turbidity conditions. Salamanders decreased activity in response to predator chemical cues matched with predator visual cues or mismatched with non-predator visual cues. Salamanders also increased latency to first move to predator chemical cues mismatched with non-predator visual cues. Salamanders decreased activity and increased latency to first move more in clear as opposed to turbid conditions in all treatment combinations. Our results indicate that salamanders under all conditions and treatments preferentially rely on chemical cues to determine antipredator behavior, although visual cues are potentially utilized in conjunction for latency to first move. Our results also have potential conservation implications, as decreased antipredator behavior was seen in turbid conditions. These results reveal complexity of antipredator behavior in response to multiple cues under different environmental conditions, which is especially important when considering endangered species. Copyright © 2016 Elsevier B.V. All rights reserved.

Auditory- and Vestibular-Evoked Potentials Correlate with Motor and Non-Motor Features of Parkinson’s Disease

PubMed Central

Shalash, Ali Soliman; Hassan, Dalia Mohamed; Elrassas, Hanan Hani; Salama, Mohamed Mosaad; Méndez-Hernández, Edna; Salas-Pacheco, José M.; Arias-Carrión, Oscar

2017-01-01

Degeneration of several brainstem nuclei has been long related to motor and non-motor symptoms (NMSs) of Parkinson’s disease (PD). Nevertheless, due to technical issues, there are only a few studies that correlate that association. Brainstem auditory-evoked potential (BAEP) and vestibular-evoked myogenic potential (VEMP) responses represent a valuable tool for brainstem assessment. Here, we investigated the abnormalities of BAEPs, ocular VEMPs (oVEMPs), and cervical VEMPs (cVEMPs) in patients with PD and its correlation to the motor and NMSs. Fifteen patients diagnosed as idiopathic PD were evaluated by Unified Parkinson’s Disease Rating Scale and its subscores, Hoehn and Yahr scale, Schwab and England scale, and Non-Motor Symptoms Scale. PD patients underwent pure-tone, speech audiometry, tympanometry, BAEP, oVEMPs, and cVEMPs, and compared to 15 age-matched control subjects. PD subjects showed abnormal BAEP wave morphology, prolonged absolute latencies of wave V and I–V interpeak latencies. Absent responses were the marked abnormality seen in oVEMP. Prolonged latencies with reduced amplitudes were seen in cVEMP responses. Rigidity and bradykinesia were correlated to the BAEP and cVEMP responses contralateral to the clinically more affected side. Contralateral and ipsilateral cVEMPs were significantly correlated to sleep (p = 0.03 and 0.001), perception (p = 0.03), memory/cognition (p = 0.025), and urinary scores (p = 0.03). The oVEMP responses showed significant correlations to cardiovascular (p = 0.01) and sexual dysfunctions (p = 0.013). PD is associated with BAEP and VEMP abnormalities that are correlated to the motor and some non-motor clinical characteristics. These abnormalities could be considered as potential electrophysiological biomarkers for brainstem dysfunction and its associated motor and non-motor features. PMID:28289399

Short latency compound action potentials from mammalian gravity receptor organs

NASA Technical Reports Server (NTRS)

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

1999-01-01

Gravity receptor function was characterized in four mammalian species using far-field vestibular evoked potentials (VsEPs). VsEPs are compound action potentials of the vestibular nerve and central relays that are elicited by linear acceleration ramps applied to the cranium. Rats, mice, guinea pigs, and gerbils were studied. In all species, response onset occurred within 1.5 ms of the stimulus onset. Responses persisted during intense (116 dBSPL) wide-band (50 to 50 inverted question mark omitted inverted question mark000 Hz) forward masking, whereas auditory responses to intense clicks (112 dBpeSPL) were eliminated under the same conditions. VsEPs remained after cochlear extirpation but were eliminated following bilateral labyrinthectomy. Responses included a series of positive and negative peaks that occurred within 8 ms of stimulus onset (range of means at +6 dBre: 1.0 g/ms: P1=908 to 1062 micros, N1=1342 to 1475 micros, P2=1632 to 1952 micros, N2=2038 to 2387 micros). Mean response amplitudes at +6 dBre: 1.0 g/ms ranged from 0.14 to 0.99 microV. VsEP input/output functions revealed latency slopes that varied across peaks and species ranging from -19 to -51 micros/dB. Amplitude-intensity slopes also varied ranging from 0.04 to 0.08 microV/dB for rats and mice. Latency values were comparable to those of birds although amplitudes were substantially smaller in mammals. VsEP threshold values were considerably higher in mammals compared to birds and ranged from -8.1 to -10.5 dBre 1.0 g/ms across species. These results support the hypothesis that mammalian gravity receptors are less sensitive to dynamic stimuli than are those of birds.

Language-motor interference reflected in MEG beta oscillations.

PubMed

Klepp, Anne; Niccolai, Valentina; Buccino, Giovanni; Schnitzler, Alfons; Biermann-Ruben, Katja

2015-04-01

The involvement of the brain's motor system in action-related language processing can lead to overt interference with simultaneous action execution. The aim of the current study was to find evidence for this behavioural interference effect and to investigate its neurophysiological correlates using oscillatory MEG analysis. Subjects performed a semantic decision task on single action verbs, describing actions executed with the hands or the feet, and abstract verbs. Right hand button press responses were given for concrete verbs only. Therefore, longer response latencies for hand compared to foot verbs should reflect interference. We found interference effects to depend on verb imageability: overall response latencies for hand verbs did not differ significantly from foot verbs. However, imageability interacted with effector: while response latencies to hand and foot verbs with low imageability were equally fast, those for highly imageable hand verbs were longer than for highly imageable foot verbs. The difference is reflected in motor-related MEG beta band power suppression, which was weaker for highly imageable hand verbs compared with highly imageable foot verbs. This provides a putative neuronal mechanism for language-motor interference where the involvement of cortical hand motor areas in hand verb processing interacts with the typical beta suppression seen before movements. We found that the facilitatory effect of higher imageability on action verb processing time is perturbed when verb and motor response relate to the same body part. Importantly, this effect is accompanied by neurophysiological effects in beta band oscillations. The attenuated power suppression around the time of movement, reflecting decreased cortical excitability, seems to result from motor simulation during action-related language processing. This is in line with embodied cognition theories. Copyright © 2015. Published by Elsevier Inc.

Noisy anthropogenic infrastructure interferes with alarm responses in Savannah sparrows (Passerculus sandwichensis)

PubMed Central

Koper, Nicola

2018-01-01

Many birds rely on anti-predator communication to protect their nests; however, anthropogenic noise from industrial activities such as oil and gas development may disrupt acoustic communication. Here, we conducted acoustic playback experiments to determine whether Savannah sparrows (Passerculus sandwichensis) responded to conspecific alarm calls by delaying feeding visits, and whether this response was impaired by noise-producing natural gas compressor stations, generator- or grid-powered screw pump oil wells, and noise amplitude. We played alarm calls, and, as a control, western meadowlark songs, to Savannah sparrows as they approached their nests to feed their nestlings, and measured feeding latency. The greatest impacts on behaviour were detected at the noisiest treatment, compressor stations; feeding latency was shortened here compared with control sites, which may expose nests to greater predation risk. As noise amplitudes increased, Savannah sparrows took longer to feed following meadowlark playbacks, perhaps because noise interfered with interpretation of acoustic cues. The effects of compressor stations on anti-predator behaviour may be best explained by the distracting effects of anthropogenic noise, while increases in feeding latency following meadowlark playbacks may be explained by a heightened response threshold caused by acoustic masking. Industrial infrastructure can influence the reproductive success of wildlife through its impact on perception and interpretation of conspecific signals, but these effects are complex. PMID:29892404

Why does picture naming take longer than word reading? The contribution of articulatory processes.

PubMed

Riès, Stéphanie; Legou, Thierry; Burle, Borís; Alario, F-Xavier; Malfait, Nicole

2012-10-01

Since the 19th century, it has been known that response latencies are longer for naming pictures than for reading words aloud. While several interpretations have been proposed, a common general assumption is that this difference stems from cognitive word-selection processes and not from articulatory processes. Here we show that, contrary to this widely accepted view, articulatory processes are also affected by the task performed. To demonstrate this, we used a procedure that to our knowledge had never been used in research on language processing: response-latency fractionating. Along with vocal onsets, we recorded the electromyographic (EMG) activity of facial muscles while participants named pictures or read words aloud. On the basis of these measures, we were able to fractionate the verbal response latencies into two types of time intervals: premotor times (from stimulus presentation to EMG onset), mostly reflecting cognitive processes, and motor times (from EMG onset to vocal onset), related to motor execution processes. We showed that premotor and motor times are both longer in picture naming than in reading, although than in reading, although articulation is already initiated in the latter measure. Future studies based on this new approach should bring valuable clues for a better understanding of the relation between the cognitive and motor processes involved in speech production.

Peripheral generators of the vestibular evoked potentials (VsEPs) in the chick.

PubMed

Weisleder, P; Jones, T A; Rubel, E W

1990-10-01

Electrophysiological activity in response to linear acceleration stimuli was recorded from young chickens by means of subcutaneous electrodes. This investigation had 2 purposes: (1) to establish the vestibular origin of the potentials; and (2) to investigate the contribution of each vestibular labyrinth to the response. The stimuli consisted of pulses of linear acceleration delivered by a mechanical vibrator (shaker). In the first set of experiments vestibular evoked potentials (VsEPs) were recorded prior to and 24 h after bilateral cochlea removal. In the second set of experiments responses were recorded before and after unilateral or bilateral intralabyrinthine injections of tetrodotoxin (TTX). Different groups of subjects were used for each experimental condition. The general morphology of the VsEPs was maintained after bilateral cochlea removal. Absolute latency of wave P2, the most prominent component of the response, was not significantly affected by the manipulation. Unilateral intralabyrinthine TTX injections consistently prolonged the latency and reduced the amplitude of wave P2. Following binaural TTX injections we were unable to elicit responses at the acceleration levels used in this study. The results from these experiments suggest that: (1) the activity recorded in response to linear acceleration stimuli is vestibular in origin; (2) when recorded from intact animals the evoked response is composed of activity from both vestibular systems; and (3) TTX consistently blocks the activity of the vestibular portion of the VIIIth cranial nerve.

Central Auditory Development: Evidence from CAEP Measurements in Children Fit with Cochlear Implants

ERIC Educational Resources Information Center

Dorman, Michael F.; Sharma, Anu; Gilley, Phillip; Martin, Kathryn; Roland, Peter

2007-01-01

In normal-hearing children the latency of the P1 component of the cortical evoked response to sound varies as a function of age and, thus, can be used as a biomarker for maturation of central auditory pathways. We assessed P1 latency in 245 congenitally deaf children fit with cochlear implants following various periods of auditory deprivation. If…

Choice Latency as a Cue for Children's Subjective Confidence in the Correctness of Their Answers

ERIC Educational Resources Information Center

Koriat, Asher; Ackerman, Rakefet

2010-01-01

Research with adults indicates that confidence in the correctness of an answer decreases as a function of the amount of time it takes to reach that answer, suggesting that people use response latency as a mnemonic cue for subjective confidence. Experiment 1 extended investigation to 2nd, 3rd and 5th graders. When children chose the answer to…

The Development of Linear Syllogistic Reasoning. Technical Report No. 5. Cognitive Development Series.

ERIC Educational Resources Information Center

Sternberg, Robert J.

About 25 children in each of grades 3, 5, 7, 9, and 11 were tested in their ability to solve linear syllogisms, such as: John is taller than Mary. Mary is taller than Pete. Who is tallest--John, Mary, or Pete? Response latencies and error rates decreased across grade levels and sessions. Component latencies also generally decreased with increasing…

Effects of Prenominal Adjective Ordering on Children's Latencies and Errors in an Immediate Sentence Recall Task.

ERIC Educational Resources Information Center

Freedle, Roy; Hall, William S.

A total of 34 children, ages 2 and a half to 6, were presented with sentences for imitation that either violated or honored a prenominal adjective ordering rule, which requires that size adjectives must precede color adjectives. Two response measures were evaluated in terms of these sentence types: latency to begin a sentence imitation and recall…

Role of microRNAs in herpesvirus latency and persistence.

PubMed

Grey, Finn

2015-04-01

The identification of virally encoded microRNAs (miRNAs) has had a major impact on the field of herpes virology. Given their ability to target cellular and viral transcripts, and the lack of immune response to small RNAs, miRNAs represent an ideal mechanism of gene regulation during viral latency and persistence. In this review, we discuss the role of miRNAs in virus latency and persistence, specifically focusing on herpesviruses. We cover the current knowledge on miRNAs in establishing and maintaining virus latency and promoting survival of infected cells through targeting of both viral and cellular transcripts, highlighting key publications in the field. We also discuss potential areas of future research and how novel technologies may aid in determining how miRNAs shape virus latency in the context of herpesvirus infections. © 2015 The Author.

Tactile responses of hindpaw, forepaw and whisker neurons in the thalamic ventrobasal complex of anesthetized rats

PubMed Central

Aguilar, J; Morales-Botello, M L; Foffani, G

2008-01-01

The majority of studies investigating responses of thalamocortical neurons to tactile stimuli have focused on the whisker representation of the rat thalamus: the ventral–posterior–medial nucleus (VPM). To test whether the basic properties of thalamocortical responses to tactile stimuli could be extended to the entire ventrobasal complex, we recorded single neurons from the whisker, forepaw and hindpaw thalamic representations. We performed a systematic analysis of responses to stereotyped tactile stimuli − 500 ms pulses (i.e. ON–OFF stimuli) or 1 ms pulses (i.e. impulsive stimuli) − under two different anesthetics (pentobarbital or urethane). We obtained the following main results: (i) the tuning of cells to ON vs. OFF stimuli displayed a gradient across neurons, so that two-thirds of cells responded more to ON stimuli and one-third responded more to OFF stimuli; (ii) on average, response magnitudes did not differ between ON and OFF stimuli, whereas latencies of response to OFF stimuli were a few milliseconds longer; (iii) latencies of response to ON and OFF stimuli were highly correlated; (iv) responses to impulsive stimuli and ON stimuli showed a strong correlation, whereas the relationship between the responses to impulsive stimuli and OFF stimuli was subtler; (v) unlike ON responses, OFF responses did not decrease when stimuli were moved from the receptive field center to a close location in the excitatory surround. We obtained the same results for hindpaw, forepaw and whisker neurons. Our results support the view of a neurophysiologically homogeneous ventrobasal complex, in which OFF responses participate in the structure of the spatiotemporal receptive field of thalamocortical neurons for tactile stimuli. PMID:18190520

Audiological and electrophysiological alterations in HIV-infected individuals subjected or not to antiretroviral therapy.

PubMed

Matas, Carla Gentile; Samelli, Alessandra Giannella; Magliaro, Fernanda Cristina Leite; Segurado, Aluisio

2017-08-02

The Human Immunodeficiency Virus (HIV) and infections related to it can affect multiple sites in the hearing system. The use of High-Activity Anti-Retroviral Therapy (HAART) can cause side effects such as ototoxicity. Thus, no consistent patterns of hearing impairment in adults with Human Immunodeficiency Virus / Acquired Immune Deficiency Syndrome have been established, and the problems that affect the hearing system of this population warrant further research. This study aimed to compare the audiological and electrophysiological data of Human Immunodeficiency Virus-positive patients with and without Acquired Immune Deficiency Syndrome, who were receiving High-Activity Anti-Retroviral Therapy, to healthy individuals. It was a cross-sectional study conducted with 71 subjects (30-48 years old), divided into groups: Research Group I: 16 Human Immunodeficiency Virus-positive individuals without Acquired Immunodeficiency Syndrome (not receiving antiretroviral treatment); Research Group II: 25 Human Immunodeficiency Virus-positive individuals with Acquired Immunodeficiency Syndrome (receiving antiretroviral treatment); Control Group: 30 healthy subjects. All individuals were tested by pure-tone air conduction thresholds at 0.25-8kHz, extended high frequencies at 9-20kHz, electrophysiological tests (Auditory Brainstem Response - ABR, Middle Latency Responses - MLR, Cognitive Potential - P300). Research Group I and Research Group II had higher hearing thresholds in both conventional and high frequency audiometry when compared to the control group, prolonged latency of waves I, III, V and interpeak I-V in Auditory Brainstem Response and prolonged latency of P300 Cognitive Potential. Regarding Middle Latency Responses, there was a decrease in the amplitude of the Pa wave of Research Group II compared to the Research Group I. Both groups with Human Immunodeficiency Virus had higher hearing thresholds when compared to healthy individuals (group exposed to antiretroviral treatment showed the worst hearing threshold) and seemed to have lower neuroelectric transmission speed along the auditory pathway in the brainstem, subcortical and cortical regions. Copyright © 2017. Published by Elsevier Editora Ltda.

Deviance detection based on regularity encoding along the auditory hierarchy: electrophysiological evidence in humans.

PubMed

Escera, Carles; Leung, Sumie; Grimm, Sabine

2014-07-01

Detection of changes in the acoustic environment is critical for survival, as it prevents missing potentially relevant events outside the focus of attention. In humans, deviance detection based on acoustic regularity encoding has been associated with a brain response derived from the human EEG, the mismatch negativity (MMN) auditory evoked potential, peaking at about 100-200 ms from deviance onset. By its long latency and cerebral generators, the cortical nature of both the processes of regularity encoding and deviance detection has been assumed. Yet, intracellular, extracellular, single-unit and local-field potential recordings in rats and cats have shown much earlier (circa 20-30 ms) and hierarchically lower (primary auditory cortex, medial geniculate body, inferior colliculus) deviance-related responses. Here, we review the recent evidence obtained with the complex auditory brainstem response (cABR), the middle latency response (MLR) and magnetoencephalography (MEG) demonstrating that human auditory deviance detection based on regularity encoding-rather than on refractoriness-occurs at latencies and in neural networks comparable to those revealed in animals. Specifically, encoding of simple acoustic-feature regularities and detection of corresponding deviance, such as an infrequent change in frequency or location, occur in the latency range of the MLR, in separate auditory cortical regions from those generating the MMN, and even at the level of human auditory brainstem. In contrast, violations of more complex regularities, such as those defined by the alternation of two different tones or by feature conjunctions (i.e., frequency and location) fail to elicit MLR correlates but elicit sizable MMNs. Altogether, these findings support the emerging view that deviance detection is a basic principle of the functional organization of the auditory system, and that regularity encoding and deviance detection is organized in ascending levels of complexity along the auditory pathway expanding from the brainstem up to higher-order areas of the cerebral cortex.

Testing coherent reflection in chinchilla: Auditory-nerve responses predict stimulus-frequency emissions

PubMed Central

Shera, Christopher A.; Tubis, Arnold; Talmadge, Carrick L.

2008-01-01

Coherent-reflection theory explains the generation of stimulus-frequency and transient-evoked otoacoustic emissions by showing how they emerge from the coherent “backscattering” of forward-traveling waves by mechanical irregularities in the cochlear partition. Recent published measurements of stimulus-frequency otoacoustic emissions (SFOAEs) and estimates of near-threshold basilar-membrane (BM) responses derived from Wiener-kernel analysis of auditory-nerve responses allow for comprehensive tests of the theory in chinchilla. Model predictions are based on (1) an approximate analytic expression for the SFOAE signal in terms of the BM traveling wave and its complex wave number, (2) an inversion procedure that derives the wave number from BM traveling waves, and (3) estimates of BM traveling waves obtained from the Wiener-kernel data and local scaling assumptions. At frequencies above 4 kHz, predicted median SFOAE phase-gradient delays and the general shapes of SFOAE magnitude-versus-frequency curves are in excellent agreement with the measurements. At frequencies below 4 kHz, both the magnitude and the phase of chinchilla SFOAEs show strong evidence of interference between short- and long-latency components. Approximate unmixing of these components, and association of the long-latency component with the predicted SFOAE, yields close agreement throughout the cochlea. Possible candidates for the short-latency SFOAE component, including wave-fixed distortion, are considered. Both empirical and predicted delay ratios (long-latency SFOAE delay∕BM delay) are significantly less than 2 but greater than 1. Although these delay ratios contradict models in which SFOAE generators couple primarily into cochlear compression waves, they are consistent with the notion that forward and reverse energy propagation in the cochlea occurs predominantly by means of traveling pressure-difference waves. The compelling overall agreement between measured and predicted delays suggests that the coherent-reflection model captures the dominant mechanisms responsible for the generation of reflection-source otoacoustic emissions. PMID:18646984

Response Inhibition and ADHD Traits: Correlates and Heritability in a Community Sample

ERIC Educational Resources Information Center

Crosbie, J.; Arnold, P.; Paterson, A.; Swanson, J.; Dupuis, A.; Li, X.; Shan, J.; Goodale, T.; Tam, C.; Strug, L. J.; Schachar, R. J.

2013-01-01

Endophenotypes or intermediate phenotypes are of great interest in neuropsychiatric genetics because of their potential for facilitating gene discovery. We evaluated response inhibition, latency and variability measures derived from the stop task as endophenotypes of ADHD by testing whether they were related to ADHD traits in the general…

The Development from Effortful to Automatic Processing in Mathematical Cognition.

ERIC Educational Resources Information Center

Kaye, Daniel B.; And Others

This investigation capitalizes upon the information processing models that depend upon measurement of latency of response to a mathematical problem and the decomposition of reaction time (RT). Simple two term addition problems were presented with possible solutions for true-false verification, and accuracy and RT to response were recorded. Total…

M.I.T./Canadian vestibular experiments on the Spacelab-1 mission. V - Postural responses following exposure to weightlessness

NASA Technical Reports Server (NTRS)

Kenyon, R. V.; Young, L. R.

1986-01-01

The four science crewmembers of Spacelab-1 were tested for postural control before and after a 10 day mission in weightlessness. Previous reports have shown changes in astronaut postural behavior following a return to earth's 1-g field. This study was designed to identify changes in EMG latency and amplitudes that might explain the instabilities observed post-flight. Erect posture was tested having the subject stand on a pneumatically driven posture platform which pitched rapidly and unexpectedly about the ankles causing dorsi- and plantarflexion. Electromyographic (EMG) activity from the tibialis anterior and the gastrocnemius-soleus muscles was measured during eyes open and eyes closed trials. The early (pre 500 ms) EMG response characteristics (latency, amplitude) in response to a disturbance in the posture of the subject were apparently unchanged by the 10 days of weightlessness. However, the late (post 500 ms) response showed higher amplitudes than was found pre-flight. General postural control was quantitatively measured pre- and post-flight by a 'sharpened Romberg Rails test'. This test showed decrements in standing stability with eyes closed for several days post-flight.

The segment as the minimal planning unit in speech production and reading aloud: evidence and implications.

PubMed

Kawamoto, Alan H; Liu, Qiang; Kello, Christopher T

2015-01-01

Speech production and reading aloud studies have much in common, especially the last stages involved in producing a response. We focus on the minimal planning unit (MPU) in articulation. Although most researchers now assume that the MPU is the syllable, we argue that it is at least as small as the segment based on negative response latencies (i.e., response initiation before presentation of the complete target) and longer initial segment durations in a reading aloud task where the initial segment is primed. We also discuss why such evidence was not found in earlier studies. Next, we rebut arguments that the segment cannot be the MPU by appealing to flexible planning scope whereby planning units of different sizes can be used due to individual differences, as well as stimulus and experimental design differences. We also discuss why negative response latencies do not arise in some situations and why anticipatory coarticulation does not preclude the segment MPU. Finally, we argue that the segment MPU is also important because it provides an alternative explanation of results implicated in the serial vs. parallel processing debate.

Evoked Cavernous Activity: Normal Values

PubMed Central

Yang, Claire C.; Yilmaz, Ugur; Vicars, Brenda G.

2009-01-01

Purpose We present normative data for evoked cavernous activity (ECA), an electrodiagnostic test that evaluates the autonomic innervation of the corpora cavernosa. Material and Methods We enrolled 37 healthy, sexually active and potent men for the study. Each subject completed an IIEF questionnaire and underwent simultaneous ECA and hand and foot sympathetic skin response (SSR) testing. The sympathetic skin response tests were performed as autonomic controls. Results Thirty six men had discernible ECA and SSRs. The mean IIEF erectile domain score was 27. ECA is a low frequency wave that is morphologically and temporally similar in both corpora. The amplitudes of the responses were highly variable. The latencies, although variable, always occurred after the hand SSR. There was no change in the quality or the latency of the ECA with age. Conclusions ECA is measurable in healthy, potent men in a wide range of ages. Similar to other evoked responses of the autonomic nervous system, the measured waveform is highly variable, but its presence is consistent. The association between ECA and erectile function is to be determined. PMID:18423763

Reticular formation responses to magnetic brain stimulation of primary motor cortex

PubMed Central

Fisher, Karen M; Zaaimi, Boubker; Baker, Stuart N

2012-01-01

Transcranial magnetic stimulation (TMS) of cerebral cortex is a popular technique for the non-invasive investigation of motor function. TMS is often assumed to influence spinal circuits solely via the corticospinal tract. We were interested in possible trans-synaptic effects of cortical TMS on the ponto-medullary reticular formation in the brainstem, which is the source of the reticulospinal tract and could also generate spinal motor output. We recorded from 210 single units in the reticular formation of three anaesthetized macaque monkeys whilst TMS was performed over primary motor cortex. Short latency responses were observed consistent with activation of a cortico-reticular pathway. However, we also demonstrated surprisingly powerful responses at longer latency, which often appeared at lower threshold than the earlier effects. These late responses seemed to be generated partly as a consequence of the sound click made by coil discharge, and changed little with coil location. This novel finding has implications for the design of future studies using TMS, as well as suggesting a means of non-invasively probing an otherwise inaccessible important motor centre. PMID:22674723

Reticular formation responses to magnetic brain stimulation of primary motor cortex.

PubMed

Fisher, Karen M; Zaaimi, Boubker; Baker, Stuart N

2012-08-15

Transcranial magnetic stimulation (TMS) of cerebral cortex is a popular technique for the non-invasive investigation of motor function. TMS is often assumed to influence spinal circuits solely via the corticospinal tract. We were interested in possible trans-synaptic effects of cortical TMS on the ponto-medullary reticular formation in the brainstem, which is the source of the reticulospinal tract and could also generate spinal motor output. We recorded from 210 single units in the reticular formation of three anaesthetized macaque monkeys whilst TMS was performed over primary motor cortex. Short latency responses were observed consistent with activation of a cortico-reticular pathway. However, we also demonstrated surprisingly powerful responses at longer latency, which often appeared at lower threshold than the earlier effects. These late responses seemed to be generated partly as a consequence of the sound click made by coil discharge, and changed little with coil location. This novel finding has implications for the design of future studies using TMS, as well as suggesting a means of non-invasively probing an otherwise inaccessible important motor centre.

Monaural and binaural response properties of neurons in the inferior colliculus of the rabbit: effects of sodium pentobarbital.

PubMed

Kuwada, S; Batra, R; Stanford, T R

1989-02-01

1. We studied the effects of sodium pentobarbital on 22 neurons in the inferior colliculus (IC) of the rabbit. We recorded changes in the sensitivity of these neurons to monaural stimulation and to ongoing interaural time differences (ITDs). Monaural stimuli were tone bursts at or near the neuron's best frequency. The ITD was varied by delivering tones that differed by 1 Hz to the two ears, resulting in a 1-Hz binaural beat. 2. We assessed a neuron's ITD sensitivity by calculating three measures from the responses to binaural beats: composite delay, characteristic delay (CD), and characteristic phase (CP). To obtain the composite delay, we first derived period histograms by averaging, showing the response at each stimulating frequency over one period of the beat frequency. Second, the period histograms were replotted as a function of their equivalent interaural delay and then averaged together to yield the composite delay curve. Last, we calculated the composite peak or trough delay by fitting a parabola to the peak or trough of this composite curve. The composite delay curve represents the average response to all frequencies within the neuron's responsive range, and the peak reflects the interaural delay that produces the maximum response. The CD and CP were estimated from a weighted fit of a regression line to the plot of the mean interaural phase of the response versus the stimulating frequency. The slope and phase intercept of this regression line yielded estimates of CD and CP, respectively. These two quantities are thought to reflect the mechanism of ITD sensitivity, which involves the convergence of phase-locked inputs on a binaural cell. The CD estimates the difference in the time required for the two inputs to travel from either ear to this cell, whereas the CP reflects the interaural phase difference of the inputs at this cell. 3. Injections of sodium pentobarbital at subsurgical dosages (less than 25 mg/kg) almost invariably altered the neuron's response rate, response latency, response pattern, and spontaneous activity. Most of these changes were predictable and consistent with an enhancement of inhibitory influences. For example, if the earliest response was inhibitory, later excitation was usually reduced and latency increased. If the earliest response was excitatory, the level of this excitation was unaltered or slightly enhanced, and changes in latency were minimal. 4. The neuron's response pattern also changed in a predictable way. For example, a response with an inhibitory pause could either change to a response with a longer pause or to a response with an onset only.(ABSTRACT TRUNCATED AT 400 WORDS)

Alcohol Attenuates Load-related Activation During a Working Memory Task: Relation to Level of Response to Alcohol

PubMed Central

Paulus, Martin P.; Tapert, Susan F.; Pulido, Carmen; Schuckit, Marc A.

2008-01-01

Background A low level of response to alcohol is a major risk factor for the development of alcohol dependence, but neural correlates of this marker are unclear. Method Ten healthy volunteers were classified by median split on level of response to alcohol and underwent 2 sessions of functional magnetic resonance imaging following ingestion of a moderate dose of alcohol and a placebo. The blood oxygen level–dependent activation to an event-related visual working memory test was examined. Results The subjects exhibited longer response latencies and more errors as a function of increasing working memory load and showed a load-dependent increase in activation in dorsolateral prefrontal cortex, posterior parietal cortex, and visual cortex. Alcohol did not affect performance (errors or response latency), but attenuated the working memory load–dependent activation in the dorsolateral prefrontal cortex. During the placebo condition, individuals with a low level of response to alcohol showed greater activation in dorsolateral prefrontal cortex and posterior parietal cortex than those with a high level of response to alcohol. During the alcohol condition, groups showed similar attenuation of load-dependent brain activation in these regions. Conclusion Low-level responders relative to high-level responders exhibited an increased working memory load–dependent activation in dorsolateral prefrontal cortex and posterior parietal cortex when not exposed to alcohol. This increase in brain response was attenuated in low-level responders after ingesting a moderate dose of alcohol. PMID:16899039

Rapid feedback responses correlate with reach adaptation and properties of novel upper limb loads.

PubMed

Cluff, Tyler; Scott, Stephen H

2013-10-02

A hallmark of voluntary motor control is the ability to adjust motor patterns for novel mechanical or visuomotor contexts. Recent work has also highlighted the importance of feedback for voluntary control, leading to the hypothesis that feedback responses should adapt when we learn new motor skills. We tested this prediction with a novel paradigm requiring that human subjects adapt to a viscous elbow load while reaching to three targets. Target 1 required combined shoulder and elbow motion, target 2 required only elbow motion, and target 3 (probe target) required shoulder but no elbow motion. This simple approach controlled muscle activity at the probe target before, during, and after the application of novel elbow loads. Our paradigm allowed us to perturb the elbow during reaching movements to the probe target and identify several key properties of adapted stretch responses. Adapted long-latency responses expressed (de-) adaptation similar to reaching errors observed when we introduced (removed) the elbow load. Moreover, reaching errors during learning correlated with changes in the long-latency response, showing subjects who adapted more to the elbow load displayed greater modulation of their stretch responses. These adapted responses were sensitive to the size and direction of the viscous training load. Our results highlight an important link between the adaptation of feedforward and feedback control and suggest a key part of motor adaptation is to adjust feedback responses to the requirements of novel motor skills.

SU-E-T-350: Verification of Gating Performance of a New Elekta Gating Solution: Response Kit and Catalyst System

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

Xie, X; Cao, D; Housley, D

2014-06-01

Purpose: In this work, we have tested the performance of new respiratory gating solutions for Elekta linacs. These solutions include the Response gating and the C-RAD Catalyst surface mapping system.Verification measurements have been performed for a series of clinical cases. We also examined the beam on latency of the system and its impact on delivery efficiency. Methods: To verify the benefits of tighter gating windows, a Quasar Respiratory Motion Platform was used. Its vertical-motion plate acted as a respiration surrogate and was tracked by the Catalyst system to generate gating signals. A MatriXX ion-chamber array was mounted on its longitudinal-movingmore » platform. Clinical plans are delivered to a stationary and moving Matrix array at 100%, 50% and 30% gating windows and gamma scores were calculated comparing moving delivery results to the stationary result. It is important to note that as one moves to tighter gating windows, the delivery efficiency will be impacted by the linac's beam-on latency. Using a specialized software package, we generated beam-on signals of lengths of 1000ms, 600ms, 450ms, 400ms, 350ms and 300ms. As the gating windows get tighter, one can expect to reach a point where the dose rate will fall to nearly zero, indicating that the gating window is close to beam-on latency. A clinically useful gating window needs to be significantly longer than the latency for the linac. Results: As expected, the use of tighter gating windows improved delivery accuracy. However, a lower limit of the gating window, largely defined by linac beam-on latency, exists at around 300ms. Conclusion: The Response gating kit, combined with the C-RAD Catalyst, provides an effective solution for respiratorygated treatment delivery. Careful patient selection, gating window design, even visual/audio coaching may be necessary to ensure both delivery quality and efficiency. This research project is funded by Elekta.« less

Psychophysics of a Nociceptive Test in the Mouse: Ambient Temperature as a Key Factor for Variation

PubMed Central

Pincedé, Ivanne; Pollin, Bernard; Meert, Theo; Plaghki, Léon; Le Bars, Daniel

2012-01-01

Background The mouse is increasingly used in biomedical research, notably in behavioral neurosciences for the development of tests or models of pain. Our goal was to provide the scientific community with an outstanding tool that allows the determination of psychophysical descriptors of a nociceptive reaction, which are inaccessible with conventional methods: namely the true threshold, true latency, conduction velocity of the peripheral fibers that trigger the response and latency of the central decision-making process. Methodology/Principal Findings Basically, the procedures involved heating of the tail with a CO2 laser, recording of tail temperature with an infrared camera and stopping the heating when the animal reacted. The method is based mainly on the measurement of three observable variables, namely the initial temperature, the heating rate and the temperature reached at the actual moment of the reaction following random variations in noxious radiant heat. The initial temperature of the tail, which itself depends on the ambient temperature, very markedly influenced the behavioral threshold, the behavioral latency and the conduction velocity of the peripheral fibers but not the latency of the central decision-making. Conclusions/Significance We have validated a psychophysical approach to nociceptive reactions for the mouse, which has already been described for rats and Humans. It enables the determination of four variables, which contribute to the overall latency of the response. The usefulness of such an approach was demonstrated by providing new fundamental findings regarding the influence of ambient temperature on nociceptive processes. We conclude by challenging the validity of using as “pain index" the reaction time of a behavioral response to an increasing heat stimulus and emphasize the need for a very careful control of the ambient temperature, as a prevailing environmental source of variation, during any behavioral testing of mice. PMID:22629325

Underwater Equal-Latency Contours of a Harbor Porpoise (Phocoena phocoena) for Tonal Signals Between 0.5 and 125 kHz.

PubMed

Wensveen, Paul J; Huijser, Léonie A E; Hoek, Lean; Kastelein, Ronald A

2016-01-01

Loudness perception can be studied based on the assumption that sounds of equal loudness elicit equal reaction time (RT; or "response latency"). We measured the underwater RTs of a harbor porpoise to narrowband frequency-modulated sounds and constructed six equal-latency contours. The contours paralleled the audiogram at low sensation levels (high RTs). At high-sensation levels, contours flattened between 0.5 and 31.5 kHz but dropped substantially (RTs shortened) beyond those frequencies. This study suggests that equal-latency-based frequency weighting can emulate noise perception in porpoises for low and middle frequencies but that the RT-loudness correlation is relatively weak for very high frequencies.

Effects of chronic sleep fragmentation on wake-active neurons and the hypercapnic arousal response.

PubMed

Li, Yanpeng; Panossian, Lori A; Zhang, Jing; Zhu, Yan; Zhan, Guanxia; Chou, Yu-Ting; Fenik, Polina; Bhatnagar, Seema; Piel, David A; Beck, Sheryl G; Veasey, Sigrid

2014-01-01

Delayed hypercapnic arousals may occur in obstructive sleep apnea. The impaired arousal response is expected to promote more pronounced oxyhemoglobin desaturations. We hypothesized that long-term sleep fragmentation (SF) results in injury to or dysfunction of wake-active neurons that manifests, in part, as a delayed hypercapnic arousal response. Adult male mice were implanted for behavioral state recordings and randomly assigned to 4 weeks of either orbital platform SF (SF4wk, 30 events/h) or control conditions (Ct4wk) prior to behavioral, histological, and locus coeruleus (LC) whole cell electrophysiological evaluations. SF was successfully achieved across the 4 week study, as evidenced by a persistently increased arousal index, P < 0.01 and shortened sleep bouts, P < 0.05, while total sleep/wake times and plasma corticosterone levels were unaffected. A multiple sleep latency test performed at the onset of the dark period showed a reduced latency to sleep in SF4wk mice (P < 0.05). The hypercapnic arousal latency was increased, Ct4wk 64 ± 5 sec vs. SF4wk 154 ± 6 sec, P < 0.001, and remained elevated after a 2 week recovery (101 ± 4 sec, P < 0.001). C-fos activation in noradrenergic, orexinergic, histaminergic, and cholinergic wake-active neurons was reduced in response to hypercapnia (P < 0.05-0.001). Catecholaminergic and orexinergic projections into the cingulate cortex were also reduced in SF4wk (P < 0.01). In addition, SF4wk resulted in impaired LC neuron excitability (P < 0.01). Four weeks of sleep fragmentation (SF4wk) impairs arousal responses to hypercapnia, reduces wake neuron projections and locus coeruleus neuronal excitability, supporting the concepts that some effects of sleep fragmentation may contribute to impaired arousal responses in sleep apnea, which may not reverse immediately with therapy.

Effects of VX on Acoustic Startle Response and Acquisition of Operant Behavior in Rats

DTIC Science & Technology

2008-02-01

spontaneous motor activity , fore- and hind-limb grip strength, thermal sensitivity (paw-lick latency), rectal temperature, acoustic startle response, and...whereas spontaneous motor activity and avoidance responding were affected at doses at or above 123 µg/kg, and acoustic startle response was affected...The 60- and 70-dB stimuli were stimulus control conditions presented to ensure that there was not significant activity within the recording chamber

Brainstem auditory evoked potentials with the use of acoustic clicks and complex verbal sounds in young adults with learning disabilities.

PubMed

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

2013-01-01

Acoustic signals are transmitted through the external and middle ear mechanically to the cochlea where they are transduced into electrical impulse for further transmission via the auditory nerve. The auditory nerve encodes the acoustic sounds that are conveyed to the auditory brainstem. Multiple brainstem nuclei, the cochlea, the midbrain, the thalamus, and the cortex constitute the central auditory system. In clinical practice, auditory brainstem responses (ABRs) to simple stimuli such as click or tones are widely used. Recently, complex stimuli or complex auditory brain responses (cABRs), such as monosyllabic speech stimuli and music, are being used as a tool to study the brainstem processing of speech sounds. We have used the classic 'click' as well as, for the first time, the artificial successive complex stimuli 'ba', which constitutes the Greek word 'baba' corresponding to the English 'daddy'. Twenty young adults institutionally diagnosed as dyslexic (10 subjects) or light dyslexic (10 subjects) comprised the diseased group. Twenty sex-, age-, education-, hearing sensitivity-, and IQ-matched normal subjects comprised the control group. Measurements included the absolute latencies of waves I through V, the interpeak latencies elicited by the classical acoustic click, the negative peak latencies of A and C waves, as well as the interpeak latencies of A-C elicited by the verbal stimulus 'baba' created on a digital speech synthesizer. The absolute peak latencies of waves I, III, and V in response to monoaural rarefaction clicks as well as the interpeak latencies I-III, III-V, and I-V in the dyslexic subjects, although increased in comparison with normal subjects, did not reach the level of a significant difference (p<0.05). However, the absolute peak latencies of the negative wave C and the interpeak latencies of A-C elicited by verbal stimuli were found to be increased in the dyslexic group in comparison with the control group (p=0.0004 and p=0.045, respectively). In the subgroup consisting of 10 patients suffering from 'other learning disabilities' and who were characterized as with 'light' dyslexia according to dyslexia tests, no significant delays were found in peak latencies A and C and interpeak latencies A-C in comparison with the control group. Acoustic representation of a speech sound and, in particular, the disyllabic word 'baba' was found to be abnormal, as low as the auditory brainstem. Because ABRs mature in early life, this can help to identify subjects with acoustically based learning problems and apply early intervention, rehabilitation, and treatment. Further studies and more experience with more patients and pathological conditions such as plasticity of the auditory system, cochlear implants, hearing aids, presbycusis, or acoustic neuropathy are necessary until this type of testing is ready for clinical application. © 2013 Elsevier Inc. All rights reserved.

Virtual reality and telerobotics applications of an Address Recalculation Pipeline

NASA Technical Reports Server (NTRS)

Regan, Matthew; Pose, Ronald

1994-01-01

The technology described in this paper was designed to reduce latency to user interactions in immersive virtual reality environments. It is also ideally suited to telerobotic applications such as interaction with remote robotic manipulators in space or in deep sea operations. in such circumstances the significant latency is observed response to user stimulus which is due to communications delays, and the disturbing jerkiness due to low and unpredictable frame rates on compressed video user feedback or computationally limited virtual worlds, can be masked by our techniques. The user is provided with highly responsive visual feedback independent of communication or computational delays in providing physical video feedback or in rendering virtual world images. Virtual and physical environments can be combined seamlessly using these techniques.

Carboxyl-Terminal Amino Acids 1052 to 1082 of the Latency-Associated Nuclear Antigen (LANA) Interact with RBP-Jκ and Are Responsible for LANA-Mediated RTA Repression

PubMed Central

Jin, Yi; He, Zhiheng; Liang, Deguang; Zhang, Quanzhi; Zhang, Hongxing; Deng, Qiang

2012-01-01

Kaposi's sarcoma-associated herpesvirus (KSHV), also known as human herpesvirus 8, is closely associated with several malignancies, including Kaposi's sarcoma, primary effusion lymphoma, and multicentric Castleman's disease. KSHV can establish lifelong latency in the host, but the mechanism is not fully understood. Previous studies have proposed a feedback model in which the viral replication and transcription activator (RTA) can induce the expression of the latency-associated nuclear antigen (LANA) during early infection. LANA, in turn, represses transcription and RTA function to establish and maintain KSHV latency. The interaction between LANA and the recombination signal sequence binding protein Jκ (RBP-Jκ, also called CSL), a major transcriptional repressor of the Notch signaling pathway, is essential for RTA repression. In the present study, we show that the LANA carboxyl-terminal amino acids 1052 to 1082 are responsible for the LANA interaction with RBP-Jκ. The secondary structure of the LANA carboxyl terminus resembles the RBP-Jκ-associated module (RAM) of Notch receptor. Furthermore, deletion of the region of LANA residues 1052 to 1082 resulted in aberrant expression of RTA, leading to elevated viral lytic replication. For the first time, we dissected a conserved RBP-Jκ binding domain in LANA and demonstrated that this domain was indispensable for LANA-mediated repression of KSHV lytic genes, thus helping the virus maintain latency and control viral reactivation. PMID:22379075

Carboxyl-terminal amino acids 1052 to 1082 of the latency-associated nuclear antigen (LANA) interact with RBP-Jκ and are responsible for LANA-mediated RTA repression.

PubMed

Jin, Yi; He, Zhiheng; Liang, Deguang; Zhang, Quanzhi; Zhang, Hongxing; Deng, Qiang; Robertson, Erle S; Lan, Ke

2012-05-01

Kaposi's sarcoma-associated herpesvirus (KSHV), also known as human herpesvirus 8, is closely associated with several malignancies, including Kaposi's sarcoma, primary effusion lymphoma, and multicentric Castleman's disease. KSHV can establish lifelong latency in the host, but the mechanism is not fully understood. Previous studies have proposed a feedback model in which the viral replication and transcription activator (RTA) can induce the expression of the latency-associated nuclear antigen (LANA) during early infection. LANA, in turn, represses transcription and RTA function to establish and maintain KSHV latency. The interaction between LANA and the recombination signal sequence binding protein Jκ (RBP-Jκ, also called CSL), a major transcriptional repressor of the Notch signaling pathway, is essential for RTA repression. In the present study, we show that the LANA carboxyl-terminal amino acids 1052 to 1082 are responsible for the LANA interaction with RBP-Jκ. The secondary structure of the LANA carboxyl terminus resembles the RBP-Jκ-associated module (RAM) of Notch receptor. Furthermore, deletion of the region of LANA residues 1052 to 1082 resulted in aberrant expression of RTA, leading to elevated viral lytic replication. For the first time, we dissected a conserved RBP-Jκ binding domain in LANA and demonstrated that this domain was indispensable for LANA-mediated repression of KSHV lytic genes, thus helping the virus maintain latency and control viral reactivation.

The effect of acute tyrosine phenylalanine depletion on emotion-based decision-making in healthy adults.

PubMed

Vrshek-Schallhorn, Suzanne; Wahlstrom, Dustin; White, Tonya; Luciana, Monica

2013-04-01

Despite interest in dopamine's role in emotion-based decision-making, few reports of the effects of dopamine manipulations are available in this area in humans. This study investigates dopamine's role in emotion-based decision-making through a common measure of this construct, the Iowa Gambling Task (IGT), using Acute Tyrosine Phenylalanine Depletion (ATPD). In a between-subjects design, 40 healthy adults were randomized to receive either an ATPD beverage or a balanced amino acid beverage (a control) prior to completing the IGT, as well as pre- and post-manipulation blood draws for the neurohormone prolactin. Together with conventional IGT performance metrics, choice selections and response latencies were examined separately for good and bad choices before and after several key punishment events. Changes in response latencies were also used to predict total task performance. Prolactin levels increased significantly in the ATPD group but not in the control group. However, no significant group differences in performance metrics were detected, nor were there sex differences in outcome measures. However, the balanced group's bad deck latencies speeded up across the task, while the ATPD group's latencies remained adaptively hesitant. Additionally, modulation of latencies to the bad decks predicted total score for the ATPD group only. One interpretation is that ATPD subtly attenuated reward salience and altered the approach by which individuals achieved successful performance, without resulting in frank group differences in task performance. Copyright © 2013 Elsevier Inc. All rights reserved.

Development of a nerve conduction technique for the recurrent laryngeal nerve.

PubMed

J Kim, Sang; G Lee, Dae; Kwon, Jeong-Yi

2014-12-01

To develop a reliable and safe laryngeal nerve conduction technique and to obtain consistent parameters as normal reference values. A prospective single-arm study. A nerve conduction test was performed on the contralateral normal side in 42 patients with unilateral vocal fold palsy. The recording was performed in the intact thyroarytenoid muscle using a monopolar needle. The electrical stimulation using a 37-mm monopolar needle was applied 3 cm below the lower margin of the cricoid cartilage, just lateral to the trachea and medial to the carotid artery, and its intensity was gradually increased until the amplitude of the electrical response reached the maximum level. The latency of the evoked muscle response was acquired at the first evoked waveform deflection from the baseline. The average latency of the recurrent laryngeal nerves was 1.98 ± 0.26 ms. The latencies showed normal distribution according to the quantile-quantile plot and Kolmogorov-Smirnov test (P = .098). There was no significant difference in latencies between the right and left recurrent laryngeal nerves. Anthropometric factors including height and weight did not show any correlation with the latencies. We developed a reliable and safe laryngeal nerve conduction technique and obtained normal reference values for the recurrent laryngeal nerve conduction study. This laryngeal nerve conduction study can be an additional tool for detecting recurrent laryngeal nerve injury if it is performed in combination with the conventional laryngeal electromyography. 4. © 2014 The American Laryngological, Rhinological and Otological Society, Inc.

What Makes the Muscle Twitch: Motor System Connectivity and TMS-Induced Activity.

PubMed

Volz, Lukas J; Hamada, Masashi; Rothwell, John C; Grefkes, Christian

2015-09-01

Transcranial magnetic stimulation (TMS) of the primary motor cortex (M1) evokes several volleys of corticospinal activity. While the earliest wave (D-wave) originates from axonal activation of cortico-spinal neurons (CSN), later waves (I-waves) result from activation of mono- and polysynaptic inputs to CSNs. Different coil orientations preferentially stimulate cortical elements evoking different outputs: latero-medial-induced current (LM) elicits D-waves and short-latency electromyographic responses (MEPs); posterior-anterior current (PA) evokes early I-waves. Anterior-posterior current (AP) is more variable and tends to recruit later I-waves, featuring longer onset latencies compared with PA-TMS. We tested whether the variability in response to AP-TMS was related to functional connectivity of the stimulated M1 in 20 right-handed healthy subjects who underwent functional magnetic resonance imaging while performing an isometric contraction task. The MEP-latency after AP-TMS (relative to LM-TMS) was strongly correlated with functional connectivity between the stimulated M1 and a network involving cortical premotor areas. This indicates that stronger premotor-M1 connectivity increases the probability that AP-TMS recruits shorter latency input to CSNs. In conclusion, our data strongly support the hypothesis that TMS of M1 activates distinct neuronal pathways depending on the orientation of the stimulation coil. Particularly, AP currents seem to recruit short latency cortico-cortical projections from premotor areas. © The Author 2014. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

Temporal Tuning of Word- and Face-selective Cortex.

PubMed

Yeatman, Jason D; Norcia, Anthony M

2016-11-01

Sensitivity to temporal change places fundamental limits on object processing in the visual system. An emerging consensus from the behavioral and neuroimaging literature suggests that temporal resolution differs substantially for stimuli of different complexity and for brain areas at different levels of the cortical hierarchy. Here, we used steady-state visually evoked potentials to directly measure three fundamental parameters that characterize the underlying neural response to text and face images: temporal resolution, peak temporal frequency, and response latency. We presented full-screen images of text or a human face, alternated with a scrambled image, at temporal frequencies between 1 and 12 Hz. These images elicited a robust response at the first harmonic that showed differential tuning, scalp topography, and delay for the text and face images. Face-selective responses were maximal at 4 Hz, but text-selective responses, by contrast, were maximal at 1 Hz. The topography of the text image response was strongly left-lateralized at higher stimulation rates, whereas the response to the face image was slightly right-lateralized but nearly bilateral at all frequencies. Both text and face images elicited steady-state activity at more than one apparent latency; we observed early (141-160 msec) and late (>250 msec) text- and face-selective responses. These differences in temporal tuning profiles are likely to reflect differences in the nature of the computations performed by word- and face-selective cortex. Despite the close proximity of word- and face-selective regions on the cortical surface, our measurements demonstrate substantial differences in the temporal dynamics of word- versus face-selective responses.

Imaging the Spatio-Temporal Dynamics of Supragranular Activity in the Rat Somatosensory Cortex in Response to Stimulation of the Paws

PubMed Central

Morales-Botello, M. L.; Aguilar, J.; Foffani, G.

2012-01-01

We employed voltage-sensitive dye (VSD) imaging to investigate the spatio-temporal dynamics of the responses of the supragranular somatosensory cortex to stimulation of the four paws in urethane-anesthetized rats. We obtained the following main results. (1) Stimulation of the contralateral forepaw evoked VSD responses with greater amplitude and smaller latency than stimulation of the contralateral hindpaw, and ipsilateral VSD responses had a lower amplitude and greater latency than contralateral responses. (2) While the contralateral stimulation initially activated only one focus, the ipsilateral stimulation initially activated two foci: one focus was typically medial to the focus activated by contralateral stimulation and was stereotaxically localized in the motor cortex; the other focus was typically posterior to the focus activated by contralateral stimulation and was stereotaxically localized in the somatosensory cortex. (3) Forepaw and hindpaw somatosensory stimuli activated large areas of the sensorimotor cortex, well beyond the forepaw and hindpaw somatosensory areas of classical somatotopic maps, and forepaw stimuli activated larger cortical areas with greater activation velocity than hindpaw stimuli. (4) Stimulation of the forepaw and hindpaw evoked different cortical activation dynamics: forepaw responses displayed a clear medial directionality, whereas hindpaw responses were much more uniform in all directions. In conclusion, this work offers a complete spatio-temporal map of the supragranular VSD cortical activation in response to stimulation of the paws, showing important somatotopic differences between contralateral and ipsilateral maps as well as differences in the spatio-temporal activation dynamics in response to forepaw and hindpaw stimuli. PMID:22829873

Response Latency Measures for Biographical Inventories

DTIC Science & Technology

1991-03-01

research (Trent et al., 1989). Procedures The ASAP, followed by one or more experimental cognitive tests, was computer administered to groups of...comprehension, and binary " true /false" decision about the item. This last stage, in turn, is divided into two substages: self-referent decision...apply stage) As a first step in partitioning latencies, it would be prudent to control experimentally for item length, as had been done in a few studies

Interval timing under a behavioral microscope: Dissociating motivational and timing processes in fixed-interval performance.

PubMed

Daniels, Carter W; Sanabria, Federico

2017-03-01

The distribution of latencies and interresponse times (IRTs) of rats was compared between two fixed-interval (FI) schedules of food reinforcement (FI 30 s and FI 90 s), and between two levels of food deprivation. Computational modeling revealed that latencies and IRTs were well described by mixture probability distributions embodying two-state Markov chains. Analysis of these models revealed that only a subset of latencies is sensitive to the periodicity of reinforcement, and prefeeding only reduces the size of this subset. The distribution of IRTs suggests that behavior in FI schedules is organized in bouts that lengthen and ramp up in frequency with proximity to reinforcement. Prefeeding slowed down the lengthening of bouts and increased the time between bouts. When concatenated, latency and IRT models adequately reproduced sigmoidal FI response functions. These findings suggest that behavior in FI schedules fluctuates in and out of schedule control; an account of such fluctuation suggests that timing and motivation are dissociable components of FI performance. These mixture-distribution models also provide novel insights on the motivational, associative, and timing processes expressed in FI performance. These processes may be obscured, however, when performance in timing tasks is analyzed in terms of mean response rates.

Auditory-Cortex Short-Term Plasticity Induced by Selective Attention

PubMed Central

Jääskeläinen, Iiro P.; Ahveninen, Jyrki

2014-01-01

The ability to concentrate on relevant sounds in the acoustic environment is crucial for everyday function and communication. Converging lines of evidence suggests that transient functional changes in auditory-cortex neurons, “short-term plasticity”, might explain this fundamental function. Under conditions of strongly focused attention, enhanced processing of attended sounds can take place at very early latencies (~50 ms from sound onset) in primary auditory cortex and possibly even at earlier latencies in subcortical structures. More robust selective-attention short-term plasticity is manifested as modulation of responses peaking at ~100 ms from sound onset in functionally specialized nonprimary auditory-cortical areas by way of stimulus-specific reshaping of neuronal receptive fields that supports filtering of selectively attended sound features from task-irrelevant ones. Such effects have been shown to take effect in ~seconds following shifting of attentional focus. There are findings suggesting that the reshaping of neuronal receptive fields is even stronger at longer auditory-cortex response latencies (~300 ms from sound onset). These longer-latency short-term plasticity effects seem to build up more gradually, within tens of seconds after shifting the focus of attention. Importantly, some of the auditory-cortical short-term plasticity effects observed during selective attention predict enhancements in behaviorally measured sound discrimination performance. PMID:24551458

Glomerular latency coding in artificial olfaction.

PubMed

Yamani, Jaber Al; Boussaid, Farid; Bermak, Amine; Martinez, Dominique

2011-01-01

Sensory perception results from the way sensory information is subsequently transformed in the brain. Olfaction is a typical example in which odor representations undergo considerable changes as they pass from olfactory receptor neurons (ORNs) to second-order neurons. First, many ORNs expressing the same receptor protein yet presenting heterogeneous dose-response properties converge onto individually identifiable glomeruli. Second, onset latency of glomerular activation is believed to play a role in encoding odor quality and quantity in the context of fast information processing. Taking inspiration from the olfactory pathway, we designed a simple yet robust glomerular latency coding scheme for processing gas sensor data. The proposed bio-inspired approach was evaluated using an in-house SnO(2) sensor array. Glomerular convergence was achieved by noting the possible analogy between receptor protein expressed in ORNs and metal catalyst used across the fabricated gas sensor array. Ion implantation was another technique used to account both for sensor heterogeneity and enhanced sensitivity. The response of the gas sensor array was mapped into glomerular latency patterns, whose rank order is concentration-invariant. Gas recognition was achieved by simply looking for a "match" within a library of spatio-temporal spike fingerprints. Because of its simplicity, this approach enables the integration of sensing and processing onto a single-chip.

Auditory evoked magnetic fields to speech stimuli in newborns--effect of sleep stages.

PubMed

Pihko, E; Sambeth, A; Leppänen, P H T; Okada, Y; Lauronen, L

2004-11-30

The aim of the study was to examine whether a newborn can detect changes in a speech stimulus consisting of a fricative followed by a vowel /su/. In addition, we studied possible effect of the two sleep stages (active and quiet sleep) on the evoked magnetic responses. In young children (6 years), the same stimulus evokes a prominent deflection, consisting of two peaks. The first one (P1m) is evoked by the beginning of the fricative consonant and has a latency of about 145 ms. The second peak (P2m) with a latency of 340 ms, is evoked by the switch to the vowel. In newborns (n = 10), the waveform resembled that of the older children but latencies of the corresponding peaks were longer, 190 and 435 ms, correspondingly. The results suggest that already the newborn brain detects the change inside the auditory speech stimulus, namely the fricative sound changing into a vowel. However, the immaturity of the brain is reflected in the prolonged latencies. In addition, the responses were higher in amplitude in quiet sleep than in active sleep (F (1.9) = 36.5; p < 0.0002). This is in line with the enhanced somatosensory magnetic fields to tactile stimulation in quiet compared to active sleep in newborns.

Adaptive and Innate Transforming Growth Factor β Signaling Impact Herpes Simplex Virus 1 Latency and Reactivation▿

PubMed Central

Allen, Sariah J.; Mott, Kevin R.; Wechsler, Steven L.; Flavell, Richard A.; Town, Terrence; Ghiasi, Homayon

2011-01-01

Innate and adaptive immunity play important protective roles by combating herpes simplex virus 1 (HSV-1) infection. Transforming growth factor β (TGF-β) is a key negative cytokine regulator of both innate and adaptive immune responses. Yet, it is unknown whether TGF-β signaling in either immune compartment impacts HSV-1 replication and latency. We undertook genetic approaches to address these issues by infecting two different dominant negative TGF-β receptor type II transgenic mouse lines. These mice have specific TGF-β signaling blockades in either T cells or innate cells. Mice were ocularly infected with HSV-1 to evaluate the effects of restricted innate or adaptive TGF-β signaling during acute and latent infections. Limiting innate cell but not T cell TGF-β signaling reduced virus replication in the eyes of infected mice. On the other hand, blocking TGF-β signaling in either innate cells or T cells resulted in decreased latency in the trigeminal ganglia of infected mice. Furthermore, inhibiting TGF-β signaling in T cells reduced cell lysis and leukocyte infiltration in corneas and trigeminal ganglia during primary HSV-1 infection of mice. These findings strongly suggest that TGF-β signaling, which generally functions to dampen immune responses, results in increased HSV-1 latency. PMID:21880769

Reversal of Latency as Part of a Cure for HIV-1.

PubMed

Rasmussen, Thomas Aagaard; Tolstrup, Martin; Søgaard, Ole Schmeltz

2016-02-01

Here, the use of pharmacological agents to reverse HIV-1 latency will be explored as a therapeutic strategy towards a cure. However, while clinical trials of latency-reversing agents LRAs) have demonstrated their ability to increase production of latent HIV-1, such interventions have not had an effect on the size of the latent HIV-1 reservoir. Plausible explanations for this include insufficient host immune responses against virus-expressing cells, the presence of escape mutations in archived virus, or an insufficient scale of latency reversal. Importantly, these early studies of LRAs were primarily designed to investigate their ability to perturb the state of HIV-1 latency; using the absence of an impact on the size of the HIV-1 reservoir to discard their potential inclusion in curative strategies would be erroneous and premature. Copyright © 2015 Elsevier Ltd. All rights reserved.

Forward Masking of the Speech-Evoked Auditory Brainstem Response.

PubMed

Hodge, Sarah E; Menezes, Denise C; Brown, Kevin D; Grose, John H

2018-02-01

The hypothesis tested was that forward masking of the speech-evoked auditory brainstem response (sABR) increases peak latency as an inverse function of masker-signal interval (Δt), and that the overall persistence of forward masking is age dependent. Older listeners exhibit deficits in forward masking. If forward-masked sABRs provide an objective measure of the susceptibility of speech sounds to prior stimulation, then this provides a novel approach to examining the age dependence of temporal processing. A /da/ stimulus forward masked by speech-shaped noise (Δt = 4-64 ms) was used to measure sABRs in 10 younger and nine older participants. Forward masking of subsegments of the /da/ stimulus (Δt = 16 ms) and click trains (Δt = 0-64 ms) was also measured. Forward-masked sABRs from young participants showed an increase in latency with decreasing Δt for the initial peak. Latency shifts for later peaks were smaller and more uniform. None of the peak latencies returned to baseline by Δt = 64 ms. Forward-masked /da/ subsegments showed peak latency shifts that did not depend simply on peak position, while forward-masked click trains showed latency shifts that were dependent on click position. The sABRs from older adults were less robust but confirmed the viability of the approach. Forward masking of the sABR provides an objective measure of the susceptibility of the auditory system to prior stimulation. Failure of recovery functions to return to baseline suggests an interaction between forward masking by the prior masker and temporal effects within the stimulus itself.

Brain stem auditory-evoked response of the nonanesthetized dog.

PubMed

Marshall, A E

1985-04-01

The brain stem auditory evoked-response was measured from a group of 24 healthy dogs under conditions suitable for clinical diagnostic use. The waveforms were identified, and analysis of amplitude ratios, latencies, and interpeak latencies were done. The group was subdivided into subgroups based on tranquilization, nontranquilization, sex, and weight. Differences were not observed among any of these subgroups. All dogs responded to the click stimulus from 30 dB to 90 dB, but only 62.5% of the dogs responded at 5 dB. The total number of peaks averaged 1.6 at 5 dB, increased linearly to 6.5 at 50 dB, and remained at 6.5 to 90 dB. Frequency of recognizability of each wave was tabulated for each stimulus intensity tested; recognizability increased with increased stimulus intensity. Amplitudes of waves increased with increasing stimulus intensity, but were highly variable. The 4th wave had the greatest amplitude at the lower stimulus intensities, and the 1st wave had the greatest amplitude at the higher stimulus intensities. Amplitude ratio of the 1st to 5th wave was greater than 1 at less than or equal to 50 dB stimulus intensity, and was 1 for stimulus intensities greater than 50 dB. Interpeak latencies did not change relative to stimulus intensities. Peak latencies of each wave averaged at 5-dB hearing level for the 1st to 6th waves were 2.03, 2.72, 3.23, 4.14, 4.41, and 6.05 ms, respectively; latencies of these 6 waves at 90 dB were 0.92, 1.79, 2.46, 3.03, 3.47, and 4.86 ms, respectively. Latency decreased between 0.009 to 0.014 ms/dB for the waves.

An electrophysiological signal that precisely tracks the emergence of error awareness

PubMed Central

Murphy, Peter R.; Robertson, Ian H.; Allen, Darren; Hester, Robert; O'Connell, Redmond G.

2012-01-01

Recent electrophysiological research has sought to elucidate the neural mechanisms necessary for the conscious awareness of action errors. Much of this work has focused on the error positivity (Pe), a neural signal that is specifically elicited by errors that have been consciously perceived. While awareness appears to be an essential prerequisite for eliciting the Pe, the precise functional role of this component has not been identified. Twenty-nine participants performed a novel variant of the Go/No-go Error Awareness Task (EAT) in which awareness of commission errors was indicated via a separate speeded manual response. Independent component analysis (ICA) was used to isolate the Pe from other stimulus- and response-evoked signals. Single-trial analysis revealed that Pe peak latency was highly correlated with the latency at which awareness was indicated. Furthermore, the Pe was more closely related to the timing of awareness than it was to the initial erroneous response. This finding was confirmed in a separate study which derived IC weights from a control condition in which no indication of awareness was required, thus ruling out motor confounds. A receiver-operating-characteristic (ROC) curve analysis showed that the Pe could reliably predict whether an error would be consciously perceived up to 400 ms before the average awareness response. Finally, Pe latency and amplitude were found to be significantly correlated with overall error awareness levels between subjects. Our data show for the first time that the temporal dynamics of the Pe trace the emergence of error awareness. These findings have important implications for interpreting the results of clinical EEG studies of error processing. PMID:22470332

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

PubMed Central

2011-01-01

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

Drift in Neural Population Activity Causes Working Memory to Deteriorate Over Time.

PubMed

Schneegans, Sebastian; Bays, Paul M

2018-05-23

Short-term memories are thought to be maintained in the form of sustained spiking activity in neural populations. Decreases in recall precision observed with increasing number of memorized items can be accounted for by a limit on total spiking activity, resulting in fewer spikes contributing to the representation of each individual item. Longer retention intervals likewise reduce recall precision, but it is unknown what changes in population activity produce this effect. One possibility is that spiking activity becomes attenuated over time, such that the same mechanism accounts for both effects of set size and retention duration. Alternatively, reduced performance may be caused by drift in the encoded value over time, without a decrease in overall spiking activity. Human participants of either sex performed a variable-delay cued recall task with a saccadic response, providing a precise measure of recall latency. Based on a spike integration model of decision making, if the effects of set size and retention duration are both caused by decreased spiking activity, we would predict a fixed relationship between recall precision and response latency across conditions. In contrast, the drift hypothesis predicts no systematic changes in latency with increasing delays. Our results show both an increase in latency with set size, and a decrease in response precision with longer delays within each set size, but no systematic increase in latency for increasing delay durations. These results were quantitatively reproduced by a model based on a limited neural resource in which working memories drift rather than decay with time. SIGNIFICANCE STATEMENT Rapid deterioration over seconds is a defining feature of short-term memory, but what mechanism drives this degradation of internal representations? Here, we extend a successful population coding model of working memory by introducing possible mechanisms of delay effects. We show that a decay in neural signal over time predicts that the time required for memory retrieval will increase with delay, whereas a random drift in the stored value predicts no effect of delay on retrieval time. Testing these predictions in a multi-item memory task with an eye movement response, we identified drift as a key mechanism of memory decline. These results provide evidence for a dynamic spiking basis for working memory, in contrast to recent proposals of activity-silent storage. Copyright © 2018 Schneegans and Bays.

The Implicit Relational Assessment Procedure (IRAP) as a Measure of Implicit Relative Preferences: A First Study

ERIC Educational Resources Information Center

Power, Patricia; Barnes-Holmes, Dermot; Barnes-Holmes, Yvonne; Stewart, Ian

2009-01-01

The Implicit Relational Assessment Procedure (IRAP) was designed to examine implicit beliefs or attitudes. In Experiment 1, response latencies obtained from Irish participants on the IRAP showed a strong preference for Irish over Scottish and American over African. In contrast, responses to explicit Likert measures diverged from the IRAP…

A Show of Hands: Relations between Young Children's Gesturing and Executive Function

ERIC Educational Resources Information Center

O'Neill, Gina; Miller, Patricia H.

2013-01-01

This study brought together 2 literatures--gesturing and executive function--in order to examine the possible role of gesture in children's executive function. Children (N = 41) aged 2½-6 years performed a sorting-shift executive function task (Dimensional Change Card Sort). Responses of interest included correct sorting, response latency,…

Stretch reflex excitability of the anti-gravity ankle extensor muscle in elderly humans.

PubMed

Kawashima, N; Nakazawa, K; Yamamoto, S-I; Nozaki, D; Akai, M; Yano, H

2004-01-01

To examine whether the stretch reflex excitability of the soleus muscle changes with age, stretch reflexes at rest (REST) and during weak voluntary contractions (ACT) were elicited in 18 older and 14 younger subjects. The amplitude of the stretch reflex responses and gain, defined as the gradient of the regression line for the relation between stretch reflex responses against the angular velocity of the applied perturbation, were evaluated in each short-latency (M1) and two long-latency components (M2 and M3). It was found that in the older group, both the amplitude and gain of the M1 component did not change from the REST to the ACT conditions, whereas in the younger group both variables significantly increased from the REST to ACT conditions. The latency of the M1 component was significantly shorter under the REST condition (older vs. younger: 51.8 +/- 7.37 vs. 55.1 +/- 8.69 ms), while no group differences were found in those variables under the ACT condition, suggesting that the muscle-tendon complexes of SOL muscles of the older subjects were less elastic and had less slack, probably due to age-related histochemical alterations. Further, the Hoffman reflex (H-reflex), elicited during the REST condition in 10 older and 11 younger subjects showed no significant differences, suggesting that the soleus motoneuron response to the Ia input was comparable between the two subject groups. The histochemical alterations occurring with the ageing process might augment the short-latency stretch reflex in the SOL muscle without enhancement of motoneuronal excitability, and this effect might be masked when the muscle is voluntarily activated.

Clinical significance of vestibular evoked myogenic potentials in benign paroxysmal positional vertigo.

PubMed

Yang, Won Sun; Kim, Sung Huhn; Lee, Jong Dae; Lee, Won-Sang

2008-12-01

To investigate the vestibular evoked myogenic potentials (VEMPs) resulting in benign paroxysmal positional vertigo (BPPV) patients and to verify its clinical applications in BPPV. A prospective study. Tertiary referral dizziness center. Forty-one patients with diagnosis of BPPV and 92 healthy volunteers who underwent VEMP testing. Patients were treated by canalith repositioning maneuvers according to the affected canal, and testing of VEMP was performed at diagnosis and after treatment. Testing of VEMP was performed in BPPV patients and in the control group. The number of times the canalith repositioning maneuver was repeated until the patient's report of relief from vertigo and findings of negative positioning test were recorded to find out the relationship between VEMP results and the progress of disease. Vestibular evoked myogenic potential results of BPPV patients showed prolonged p13 and n23 latencies compared with those of the control group, and we could not find any significant difference in VEMP latencies between patients with posterior and horizontal canal type of BPPV. The number of times that the maneuver was repeated did not correlate with the degree of latency prolongation, but in the "no response" group, the number of times was considerably greater than that in the "response" group. We found that VEMP latencies are increased in BPPV patients, which may signify neuronal degenerative changes in the macula of the saccule. When an extensive neuronal damage was suspected by VEMP results such as "no response" in VEMP, the disease progress showed a chronic and resistive course. Therefore, we propose that VEMP could be a useful method to determine a clinical prognosis of patients with BPPV.

The Clinical Utility of Vestibular Evoked Myogenic Potentials in Patients of Benign Paroxysmal Positional Vertigo.

PubMed

Sreenivasan, Anuprasad; Sivaraman, Ganesan; Parida, Pradiptata Kumar; Alexander, Arun; Saxena, Sunil Kumar; Suria, Gopalakrishnan

2015-06-01

Vestibular Evoked Myogenic Potentials (VEMP) is an emerging tool to diagnose Benign Paroxysmal Positional Vertigo (BPPV). The clinical utility of VEMP has been reported only in small accord in Indian literature. To study the latency and amplitude of VEMP in patients with BPPV and compare it with that of normal subjects. The study included two groups. Group one (control group) were 18 normal subjects. Group two (test group) were 15 subjects with unilateral BPPV. Those subjects who fulfilled the selection criteria based on case history and audiological assessment were taken for the VEMP recording. The VEMP response consist of positive and negative successive waves (pI-nI), with latency values in adults about 13 and 23 milliseconds respectively. Data was analysed using Statistical Package for Social Sciences (SPSS) version 12 (Chicago, IL, USA). Unpaired t-test was employed to measure the statistical difference between control group and test group. The difference in n23 and the peak to peak amplitude between the ipsilateral and contralateral ears of the test group were statistically significant, whereas such a difference in the p13 latency turned out to be statistically insignificant. It should be noted that, out of 15 patients in the test group, five patients showed only artifact tracer recordings in both the ears which is considered as no response. The heterogeneity of the results extended from absence of VEMP to prolongation of both p13, n23; prolongation of p13 alone; and even side to side variations. Absent response from the ipsilateral ear, prolonged latency of n23 and decreased peak to peak amplitude (p13, n23), indicates the disease pathology. However, large sample size is required to draw further conclusions and to consolidate the usage of VEMP in the diagnosis of BPPV.

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

PubMed

Cobb, Kensi M; Stuart, Andrew

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

Human short-latency ocular vergence responses produced by interocular velocity differences

PubMed Central

Sheliga, B. M.; Quaia, C.; FitzGibbon, E. J.; Cumming, B. G.

2016-01-01

We studied human short-latency vergence eye movements to a novel stimulus that produces interocular velocity differences without a changing disparity signal. Sinusoidal luminance gratings moved in opposite directions (left vs. right; up vs. down) in the two eyes. The grating seen by each eye underwent ¼-wavelength shifts with each image update. This arrangement eliminated changing disparity cues, since the phase difference between the eyes alternated between 0° and 180°. We nevertheless observed robust short-latency vergence responses (VRs), whose sign was consistent with the interocular velocity differences (IOVDs), indicating that the IOVD cue in isolation can evoke short-latency VRs. The IOVD cue was effective only when the images seen by the two eyes overlapped in space. We observed equally robust VRs for opposite horizontal motions (left in one eye, right in the other) and opposite vertical motions (up in one eye, down in the other). Whereas the former are naturally generated by objects moving in depth, the latter are not part of our normal experience. To our knowledge, this is the first demonstration of a behavioral consequence of vertical IOVD. This may reflect the fact that some neurons in area MT are sensitive to these motion signals (Czuba, Huk, Cormack, & Kohn, 2014). VRs were the strongest for spatial frequencies in the range of 0.35–1 c/°, much higher than the optimal spatial frequencies for evoking ocular-following responses observed during frontoparallel motion. This suggests that the two motion signals are detected by different neuronal populations. We also produced IOVD using moving uncorrelated one-dimensional white-noise stimuli. In this case the most effective stimuli have low speed, as predicted if the drive originates in neurons tuned to high spatial frequencies (Sheliga, Quaia, FitzGibbon, & Cumming, 2016). PMID:27548089

Vestibular Evoked Myogenic Potential (VEMP) Testing: Normative Threshold Response Curves and Effects of Age

PubMed Central

Janky, Kristen L.; Shepard, Neil

2009-01-01

Background Vestibular Evoked Myogenic Potential (VEMP) testing has gained increased interest in the diagnosis of a variety of vestibular etiologies. Comparisons of P13 / N23 latency, amplitude and threshold response curves have been used to compare pathologic groups to normal controls. Appropriate characterization of these etiologies requires normative data across the frequency spectrum and age range. Purpose The objective of the current study was to test the hypothesis that significant changes in VEMP responses occur as a function of increased age across all test stimuli as well as characterize the VEMP threshold response curve across age. Research Design This project incorporated a prospective study design using a sample of convenience. Openly recruited subjects were assigned to groups according to age. Study Sample Forty-six normal controls ranging between 20 and 76 years of age participated in the study. Participants were separated by decade into 5 age categories from 20 to 60 plus years. Normal participants were characterized by having normal hearing sensitivity, no history of neurologic or balance/dizziness involvement and negative results on a direct office vestibular examination. Intervention VEMP responses were measured at threshold to click and 250, 500, 750, and 1000 Hz tone burst stimuli and at a suprathreshold level to 500 Hz toneburst stimuli at123 dBSPL. Data Collection and Analysis A mixed group factorial ANOVA and linear regression were performed to examine the effects of VEMP characteristics upon age. Results There were no significant differences between ears for any of the test parameters. There were no significant differences between age groups for n23 latency or amplitude in response to any of the stimuli. Significant mean differences did exist between age groups for p13 latency (250, 750, and 1000 Hz) and threshold (500 and 750 Hz). Age was significantly correlated with VEMP parameters. VEMP threshold was positively correlated (250, 500, 750, 1000 Hz); and amplitude was negatively correlated (500 Hz Maximum). The threshold response curves revealed best frequency tuning at 500 Hz with the highest thresholds in response to click stimuli. However, this best frequency tuning dissipated with increased age. VEMP response rates also decreased with increased age. Conclusion We have demonstrated that minor differences in VEMP responses occur with age. Given the reduced response rates and flattened frequency tuning curve for individuals over the age of 60, frequency tuning curves may not be a good diagnostic indicator for this age group. PMID:19764171

Effects of Chronic Sleep Fragmentation on Wake-Active Neurons and the Hypercapnic Arousal Response

PubMed Central

Li, Yanpeng; Panossian, Lori A.; Zhang, Jing; Zhu, Yan; Zhan, Guanxia; Chou, Yu-Ting; Fenik, Polina; Bhatnagar, Seema; Piel, David A.; Beck, Sheryl G.; Veasey, Sigrid

2014-01-01

Study Objectives: Delayed hypercapnic arousals may occur in obstructive sleep apnea. The impaired arousal response is expected to promote more pronounced oxyhemoglobin desaturations. We hypothesized that long-term sleep fragmentation (SF) results in injury to or dysfunction of wake-active neurons that manifests, in part, as a delayed hypercapnic arousal response. Design: Adult male mice were implanted for behavioral state recordings and randomly assigned to 4 weeks of either orbital platform SF (SF4wk, 30 events/h) or control conditions (Ct4wk) prior to behavioral, histological, and locus coeruleus (LC) whole cell electrophysiological evaluations. Measurements and Results: SF was successfully achieved across the 4 week study, as evidenced by a persistently increased arousal index, P < 0.01 and shortened sleep bouts, P < 0.05, while total sleep/wake times and plasma corticosterone levels were unaffected. A multiple sleep latency test performed at the onset of the dark period showed a reduced latency to sleep in SF4wk mice (P < 0.05). The hypercapnic arousal latency was increased, Ct4wk 64 ± 5 sec vs. SF4wk 154 ± 6 sec, P < 0.001, and remained elevated after a 2 week recovery (101 ± 4 sec, P < 0.001). C-fos activation in noradrenergic, orexinergic, histaminergic, and cholinergic wake-active neurons was reduced in response to hypercapnia (P < 0.05-0.001). Catecholaminergic and orexinergic projections into the cingulate cortex were also reduced in SF4wk (P < 0.01). In addition, SF4wk resulted in impaired LC neuron excitability (P < 0.01). Conclusions: Four weeks of sleep fragmentation (SF4wk) impairs arousal responses to hypercapnia, reduces wake neuron projections and locus coeruleus neuronal excitability, supporting the concepts that some effects of sleep fragmentation may contribute to impaired arousal responses in sleep apnea, which may not reverse immediately with therapy. Citation: Li Y; Panossian LA; Zhang J; Zhu Y; Zhan G; Chou YT; Fenik P; Bhatnagar S; Piel DA; Beck SG; Veasey S. Effects of chronic sleep fragmentation on wake-active neurons and the hypercapnic arousal response. SLEEP 2014;37(1):51-64. PMID:24470695

Amplitude by Peak Interaction but No Evidence of Auditory Mismatch Response Deficits to Frequency Change in Preschool-Aged Children with Fetal Alcohol Spectrum Disorders.

PubMed

Kabella, Danielle M; Flynn, Lucinda; Peters, Amanda; Kodituwakku, Piyadasa; Stephen, Julia M

2018-05-24

Prior studies indicate that the auditory mismatch response is sensitive to early alterations in brain development in multiple developmental disorders. Prenatal alcohol exposure is known to impact early auditory processing. The current study hypothesized alterations in the mismatch response in young children with fetal alcohol spectrum disorders (FASD). Participants in this study were 9 children with a FASD and 17 control children (Control) aged 3 to 6 years. Participants underwent magnetoencephalography and structural magnetic resonance imaging scans separately. We compared groups on neurophysiological mismatch negativity (MMN) responses to auditory stimuli measured using the auditory oddball paradigm. Frequent (1,000 Hz) and rare (1,200 Hz) tones were presented at 72 dB. There was no significant group difference in MMN response latency or amplitude represented by the peak located ~200 ms after stimulus presentation in the difference time course between frequent and infrequent tones. Examining the time courses to the frequent and infrequent tones separately, repeated measures analysis of variance with condition (frequent vs. rare), peak (N100m and N200m), and hemisphere as within-subject factors and diagnosis and sex as the between-subject factors showed a significant interaction of peak by diagnosis (p = 0.001), with a pattern of decreased amplitude from N100m to N200m in Control children and the opposite pattern in children with FASD. However, no significant difference was found with the simple effects comparisons. No group differences were found in the response latencies of the rare auditory evoked fields. The results indicate that there was no detectable effect of alcohol exposure on the amplitude or latency of the MMNm response to simple tones modulated by frequency change in preschool-aged children with FASD. However, while discrimination abilities to simple tones may be intact, early auditory sensory processing revealed by the interaction between N100m and N200m amplitude indicates that auditory sensory processing may be altered in children with FASD. Copyright © 2018 by the Research Society on Alcoholism.

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

PubMed Central

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

2010-01-01

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

Vocal Responses to Perturbations in Voice Auditory Feedback in Individuals with Parkinson's Disease

PubMed Central

Liu, Hanjun; Wang, Emily Q.; Metman, Leo Verhagen; Larson, Charles R.

2012-01-01

Background One of the most common symptoms of speech deficits in individuals with Parkinson's disease (PD) is significantly reduced vocal loudness and pitch range. The present study investigated whether abnormal vocalizations in individuals with PD are related to sensory processing of voice auditory feedback. Perturbations in loudness or pitch of voice auditory feedback are known to elicit short latency, compensatory responses in voice amplitude or fundamental frequency. Methodology/Principal Findings Twelve individuals with Parkinson's disease and 13 age- and sex- matched healthy control subjects sustained a vowel sound (/α/) and received unexpected, brief (200 ms) perturbations in voice loudness (±3 or 6 dB) or pitch (±100 cents) auditory feedback. Results showed that, while all subjects produced compensatory responses in their voice amplitude or fundamental frequency, individuals with PD exhibited larger response magnitudes than the control subjects. Furthermore, for loudness-shifted feedback, upward stimuli resulted in shorter response latencies than downward stimuli in the control subjects but not in individuals with PD. Conclusions/Significance The larger response magnitudes in individuals with PD compared with the control subjects suggest that processing of voice auditory feedback is abnormal in PD. Although the precise mechanisms of the voice feedback processing are unknown, results of this study suggest that abnormal voice control in individuals with PD may be related to dysfunctional mechanisms of error detection or correction in sensory feedback processing. PMID:22448258

Chromatic VEP in children with congenital colour vision deficiency.

PubMed

Tekavčič Pompe, Manca; Stirn Kranjc, Branka; Brecelj, Jelka

2010-09-01

Visual evoked potentials to chromatic stimulus (cVEP) are believed to selectively test the parvocellular visual pathway which is responsible for processing information about colour. The aim was to evaluate cVEP in children with red-green congenital colour vision deficiency. VEP responses of 15 colour deficient children were compared to 31 children with normal colour vision. An isoluminant red-green stimulus composed of horizontal gratings was presented in an onset-offset manner. The shape of the waveform was studied, as well as the latency and amplitude of positive (P) and negative (N) waves. cVEP response did not change much with increased age in colour deficient children, whereas normative data showed changes from a predominantly positive to a negative response with increased age. A P wave was present in 87% of colour deficient children (and in 100% of children with normal colour vision), whereas the N wave was absent in a great majority of colour deficient children and was present in 80% of children with normal colour vision. Therefore, the amplitude of the whole response (N-P) decreased linearly with age in colour deficient children, whereas in children with normal colour vision it increased linearly. P wave latency shortened with increased age in both groups. cVEP responses differ in children with congenital colour vision deficiency compared to children with normal colour vision. © 2010 The Authors, Ophthalmic and Physiological Optics © 2010 The College of Optometrists.

Low Latency DESDynI Data Products for Disaster Response, Resource Management and Other Applications

NASA Technical Reports Server (NTRS)

Doubleday, Joshua R.; Chien, Steve A.; Lou, Yunling

2011-01-01

We are developing onboard processor technology targeted at the L-band SAR instrument onboard the planned DESDynI mission to enable formation of SAR images onboard opening possibilities for near-real-time data products to augment full data streams. Several image processing and/or interpretation techniques are being explored as possible direct-broadcast products for use by agencies in need of low-latency data, responsible for disaster mitigation and assessment, resource management, agricultural development, shipping, etc. Data collected through UAVSAR (L-band) serves as surrogate to the future DESDynI instrument. We have explored surface water extent as a tool for flooding response, and disturbance images on polarimetric backscatter of repeat pass imagery potentially useful for structural collapse (earthquake), mud/land/debris-slides etc. We have also explored building vegetation and snow/ice classifiers, via support vector machines utilizing quad-pol backscatter, cross-pol phase, and a number of derivatives (radar vegetation index, dielectric estimates, etc.). We share our qualitative and quantitative results thus far.

Pain Processing and Vegetative Dysfunction in Fibromyalgia: A Study by Sympathetic Skin Response and Laser Evoked Potentials

PubMed Central

Ricci, Katia; Libro, Giuseppe; Vecchio, Eleonora; Delussi, Marianna; Montemurno, Anna; Iannone, Florenzo

2017-01-01

Background A dysfunction of pain processing at central and peripheral levels was reported in fibromyalgia (FM). We aimed to correlate laser evoked potentials (LEPs), Sympathetic Skin Response (SSR), and clinical features in FM patients. Methods Fifty FM patients and 30 age-matched controls underwent LEPs and SSR by the right hand and foot. The clinical evaluation included FM disability (FIQ) and severity scores (WPI), anxiety (SAS) and depression (SDS) scales, and questionnaires for neuropathic pain (DN4). Results The LEP P2 latency and amplitude and the SSR latency were increased in FM group. This latter feature was more evident in anxious patients. The LEPs habituation was reduced in FM patients and correlated to pain severity scores. In a significant number of patients (32%) with higher DN4 and FIQ scores, SSR or LEP responses were absent. Conclusions LEPs and SSR might contribute to clarifying the peripheral and central nervous system involvement in FM patients. PMID:29093972

Pain Processing and Vegetative Dysfunction in Fibromyalgia: A Study by Sympathetic Skin Response and Laser Evoked Potentials.

PubMed

de Tommaso, Marina; Ricci, Katia; Libro, Giuseppe; Vecchio, Eleonora; Delussi, Marianna; Montemurno, Anna; Lopalco, Giuseppe; Iannone, Florenzo

2017-01-01

A dysfunction of pain processing at central and peripheral levels was reported in fibromyalgia (FM). We aimed to correlate laser evoked potentials (LEPs), Sympathetic Skin Response (SSR), and clinical features in FM patients. Fifty FM patients and 30 age-matched controls underwent LEPs and SSR by the right hand and foot. The clinical evaluation included FM disability (FIQ) and severity scores (WPI), anxiety (SAS) and depression (SDS) scales, and questionnaires for neuropathic pain (DN4). The LEP P2 latency and amplitude and the SSR latency were increased in FM group. This latter feature was more evident in anxious patients. The LEPs habituation was reduced in FM patients and correlated to pain severity scores. In a significant number of patients (32%) with higher DN4 and FIQ scores, SSR or LEP responses were absent. LEPs and SSR might contribute to clarifying the peripheral and central nervous system involvement in FM patients.

Transcranial magnetic stimulation of the human brain: responses in muscles supplied by cranial nerves.

PubMed

Benecke, R; Meyer, B U; Schönle, P; Conrad, B

1988-01-01

The present investigation demonstrates that time-varying magnetic fields induced over the skull elicit distinct types of responses in muscles supplied by the cranial nerves both on the ipsilateral and the contralateral side. When the center of the copper coil was positioned 4 cm lateral to the vertex on a line from the vertex to the external auditory meatus, bilateral responses in the masseter, orbicularis oculi, mentalis, and sternocleidomastoideus muscles with a delay of about 10 to 14 ms after the stimulus occurred. Similar to the transcranially evoked muscle responses in hand muscles, the responses in the cranial muscles can be influenced in latency and amplitude by background excitation. It is concluded that these responses are induced by excitation of the face-associated motor cortex followed by multiple I-waves in the corticonuclear tract with both ipsilateral and contralateral projections to the corresponding motoneurones. Additionally, at higher stimulation strengths "short-latency" ipsilateral responses in muscles supplied by the trigeminal, facial, and accessory nerves occurred which we suggest are induced by direct stimulation of the peripheral cranial nerves in their intracisternal course. The present study confirms the bilateral projection of corticonuclear tracts in awake unanesthetised human subjects which has been observed by electrical stimulation on the exposed cortex during surgical procedures already decades ago. The present investigation will serve as a basis for the assessment of pathophysiological mechanisms involving the corticonuclear system or the peripheral cranial nerves in their proximal parts in awake humans.

Long-Latency Reductions in Gamma Power Predict Hemodynamic Changes That Underlie the Negative BOLD Signal

PubMed Central

Harris, Samuel; Bruyns-Haylett, Michael; Kennerley, Aneurin; Zheng, Ying; Martin, Chris; Jones, Myles; Redgrave, Peter; Berwick, Jason

2015-01-01

Studies that use prolonged periods of sensory stimulation report associations between regional reductions in neural activity and negative blood oxygenation level-dependent (BOLD) signaling. However, the neural generators of the negative BOLD response remain to be characterized. Here, we use single-impulse electrical stimulation of the whisker pad in the anesthetized rat to identify components of the neural response that are related to “negative” hemodynamic changes in the brain. Laminar multiunit activity and local field potential recordings of neural activity were performed concurrently with two-dimensional optical imaging spectroscopy measuring hemodynamic changes. Repeated measurements over multiple stimulation trials revealed significant variations in neural responses across session and animal datasets. Within this variation, we found robust long-latency decreases (300 and 2000 ms after stimulus presentation) in gamma-band power (30–80 Hz) in the middle-superficial cortical layers in regions surrounding the activated whisker barrel cortex. This reduction in gamma frequency activity was associated with corresponding decreases in the hemodynamic responses that drive the negative BOLD signal. These findings suggest a close relationship between BOLD responses and neural events that operate over time scales that outlast the initiating sensory stimulus, and provide important insights into the neurophysiological basis of negative neuroimaging signals. PMID:25788681

Auditory evoked functions in ground crew working in high noise environment of Mumbai airport.

PubMed

Thakur, L; Anand, J P; Banerjee, P K

2004-10-01

The continuous exposure to the relatively high level of noise in the surroundings of an airport is likely to affect the central pathway of the auditory system as well as the cognitive functions of the people working in that environment. The Brainstem Auditory Evoked Responses (BAER), Mid Latency Response (MLR) and P300 response of the ground crew employees working in Mumbai airport were studied to evaluate the effects of continuous exposure to high level of noise of the surroundings of the airport on these responses. BAER, P300 and MLR were recorded by using a Nicolet Compact-4 (USA) instrument. Audiometry was also monitored with the help of GSI-16 Audiometer. There was a significant increase in the peak III latency of the BAER in the subjects exposed to noise compared to controls with no change in their P300 values. The exposed group showed hearing loss at different frequencies. The exposure to the high level of noise caused a considerable decline in the auditory conduction upto the level of the brainstem with no significant change in conduction in the midbrain, subcortical areas, auditory cortex and associated areas. There was also no significant change in cognitive function as measured by P300 response.

Long-latency reductions in gamma power predict hemodynamic changes that underlie the negative BOLD signal.

PubMed

Boorman, Luke; Harris, Samuel; Bruyns-Haylett, Michael; Kennerley, Aneurin; Zheng, Ying; Martin, Chris; Jones, Myles; Redgrave, Peter; Berwick, Jason

2015-03-18

Studies that use prolonged periods of sensory stimulation report associations between regional reductions in neural activity and negative blood oxygenation level-dependent (BOLD) signaling. However, the neural generators of the negative BOLD response remain to be characterized. Here, we use single-impulse electrical stimulation of the whisker pad in the anesthetized rat to identify components of the neural response that are related to "negative" hemodynamic changes in the brain. Laminar multiunit activity and local field potential recordings of neural activity were performed concurrently with two-dimensional optical imaging spectroscopy measuring hemodynamic changes. Repeated measurements over multiple stimulation trials revealed significant variations in neural responses across session and animal datasets. Within this variation, we found robust long-latency decreases (300 and 2000 ms after stimulus presentation) in gamma-band power (30-80 Hz) in the middle-superficial cortical layers in regions surrounding the activated whisker barrel cortex. This reduction in gamma frequency activity was associated with corresponding decreases in the hemodynamic responses that drive the negative BOLD signal. These findings suggest a close relationship between BOLD responses and neural events that operate over time scales that outlast the initiating sensory stimulus, and provide important insights into the neurophysiological basis of negative neuroimaging signals. Copyright © 2015 Boorman et al.

The impairing effects of mental fatigue on response inhibition: An ERP study

PubMed Central

Guo, Zizheng; Chen, Ruiya; Liu, Xian; Zheng, Yan; Gong, Mingliang; Zhang, Jun

2018-01-01

Mental fatigue is one of the main reasons for the decline of response inhibition. This study aimed to explore the impairing influence of mental fatigue on a driver’s response inhibition. The effects of mental fatigue on response inhibition were assessed by comparing brain activity and behavioral indices when performing a Go/NoGo task before and after a 90-min fatigue manipulation task. Participants in the driving group performed a simulated driving task, while individuals in the control group spent the same time watching movies. We found that participants in the driving group reported higher levels of mental fatigue and had a higher percentage of eye closure and larger lateral deviations from their lane positions, which indicated there was effective manipulation of mental fatigue through a prolonged simulated driving task. After manipulation of mental fatigue, we observed increased reaction time and miss rates, delayed NoGo-N2 latency and Go-P3 latency, and decreased NoGo-P3 amplitude, which indicated that mental fatigue may slow down the speed of the inhibition process, delay the evaluation of visual stimuli and reduce the availability of attentional resources. These findings revealed the underlying neurological mechanisms of how mental fatigue impaired response inhibition. PMID:29856827

Voice responses to changes in pitch of voice or tone auditory feedback

NASA Astrophysics Data System (ADS)

Sivasankar, Mahalakshmi; Bauer, Jay J.; Babu, Tara; Larson, Charles R.

2005-02-01

The present study was undertaken to examine if a subject's voice F0 responded not only to perturbations in pitch of voice feedback but also to changes in pitch of a side tone presented congruent with voice feedback. Small magnitude brief duration perturbations in pitch of voice or tone auditory feedback were randomly introduced during sustained vowel phonations. Results demonstrated a higher rate and larger magnitude of voice F0 responses to changes in pitch of the voice compared with a triangular-shaped tone (experiment 1) or a pure tone (experiment 2). However, response latencies did not differ across voice or tone conditions. Data suggest that subjects responded to the change in F0 rather than harmonic frequencies of auditory feedback because voice F0 response prevalence, magnitude, or latency did not statistically differ across triangular-shaped tone or pure-tone feedback. Results indicate the audio-vocal system is sensitive to the change in pitch of a variety of sounds, which may represent a flexible system capable of adapting to changes in the subject's voice. However, lower prevalence and smaller responses to tone pitch-shifted signals suggest that the audio-vocal system may resist changes to the pitch of other environmental sounds when voice feedback is present. .

Developmental trends in auditory processing can provide early predictions of language acquisition in young infants.

PubMed

Chonchaiya, Weerasak; Tardif, Twila; Mai, Xiaoqin; Xu, Lin; Li, Mingyan; Kaciroti, Niko; Kileny, Paul R; Shao, Jie; Lozoff, Betsy

2013-03-01

Auditory processing capabilities at the subcortical level have been hypothesized to impact an individual's development of both language and reading abilities. The present study examined whether auditory processing capabilities relate to language development in healthy 9-month-old infants. Participants were 71 infants (31 boys and 40 girls) with both Auditory Brainstem Response (ABR) and language assessments. At 6 weeks and/or 9 months of age, the infants underwent ABR testing using both a standard hearing screening protocol with 30 dB clicks and a second protocol using click pairs separated by 8, 16, and 64-ms intervals presented at 80 dB. We evaluated the effects of interval duration on ABR latency and amplitude elicited by the second click. At 9 months, language development was assessed via parent report on the Chinese Communicative Development Inventory - Putonghua version (CCDI-P). Wave V latency z-scores of the 64-ms condition at 6 weeks showed strong direct relationships with Wave V latency in the same condition at 9 months. More importantly, shorter Wave V latencies at 9 months showed strong relationships with the CCDI-P composite consisting of phrases understood, gestures, and words produced. Likewise, infants who had greater decreases in Wave V latencies from 6 weeks to 9 months had higher CCDI-P composite scores. Females had higher language development scores and shorter Wave V latencies at both ages than males. Interestingly, when the ABR Wave V latencies at both ages were taken into account, the direct effects of gender on language disappeared. In conclusion, these results support the importance of low-level auditory processing capabilities for early language acquisition in a population of typically developing young infants. Moreover, the auditory brainstem response in this paradigm shows promise as an electrophysiological marker to predict individual differences in language development in young children. © 2012 Blackwell Publishing Ltd.

Modeling neuroendocrine stress reactivity in salivary cortisol: adjusting for peak latency variability.

PubMed

Lopez-Duran, Nestor L; Mayer, Stefanie E; Abelson, James L

2014-07-01

In this report, we present growth curve modeling (GCM) with landmark registration as an alternative statistical approach for the analysis of time series cortisol data. This approach addresses an often-ignored but critical source of variability in salivary cortisol analyses: individual and group differences in the time latency of post-stress peak concentrations. It allows for the simultaneous examination of cortisol changes before and after the peak while controlling for timing differences, and thus provides additional information that can help elucidate group differences in the underlying biological processes (e.g., intensity of response, regulatory capacity). We tested whether GCM with landmark registration is more sensitive than traditional statistical approaches (e.g., repeated measures ANOVA--rANOVA) in identifying sex differences in salivary cortisol responses to a psychosocial stressor (Trier Social Stress Test--TSST) in healthy adults (mean age 23). We used plasma ACTH measures as our "standard" and show that the new approach confirms in salivary cortisol the ACTH finding that males had longer peak latencies, higher post-stress peaks but a more intense post-peak decline. This finding would have been missed if only saliva cortisol was available and only more traditional analytic methods were used. This new approach may provide neuroendocrine researchers with a highly sensitive complementary tool to examine the dynamics of the cortisol response in a way that reduces risk of false negative findings when blood samples are not feasible.

Effect of feeding patterns on performance of a visuospatial memory task in the beagle dog: a novel cognitive-based protocol for assessing satiety.

PubMed

Chan, Joan W C; Araujo, Joseph A; Zicker, Steven C; Pun, Teresa W C; Milgram, Norton W

2005-03-01

The assessment of appetite suppressing effects, or satiating effects, of drugs or other treatments is typically based on the measurement of food consumption and body weight. The present study describes a novel cognitive-based protocol for assessing satiety in the dog based on response latency and performance accuracy on a canine test of spatial working memory, the three-component delayed-non-matching-to-position task (3cDNMP). We hypothesized that satiety, produced by providing food prior to testing, would reduce motivation to respond quickly and accurately on this food-reinforced task. Dogs were first over-trained on a variable-delay version of the 3cDNMP task. They were then pre-fed with either a single or a double portion of food prior to being tested on the same task. Pre-feeding slowed response latency, but had no effect on performance accuracy. A more pronounced increase in response latency was observed in young dogs than in old dogs when offered double portions of food. These results suggest, first, that spatial working memory capability is independent of motivation; second, that satiety is age sensitive; and third, that a cognitive protocol can provide a reliable method for evaluating the satiating effects of various foods and other compounds in the dog.

Consistent latencies of vestibular evoked myogenic potentials.

PubMed

Wang, Shou-Jen; Yeh, Te-Huei; Chang, Chun-Hsiang; Young, Yi-Ho

2008-12-01

This study investigated the association between neck length and vestibular evoked myogenic potential (VEMP) latencies in healthy children, adolescents, and adults to elucidate when VEMP latencies reach consistent levels. Findings of VEMP tests in 14 healthy children, seven healthy adolescents, and 14 healthy adults were analyzed for correlations with neck length, which was measured as the distance of a line dropping vertically from the mastoid tip to the horizontal plane passing through the clavicle. All healthy children, adolescents, and adults exhibited present VEMP responses. Children, adolescents, and adults significantly differed in p13 latency, n23 latency, and p13-n23 interval. According to receiver operating characteristic curve analysis, the optimal cutoff values of p13 and n23 latencies between children and adults were 12.6 and 19.8 msec, respectively. Because the odds ratio of p13 latency was less than that of n23 latency, n23 latency was used to discriminate VEMP latencies between children and adults. Accordingly, a cutoff value of 15.3 cm for neck length was proposed as a criterion for predicting VEMP latency within the adult range. Consequently, a positive correlation between neck length and VEMP latency was observed when neck length was <15.3 cm, while above which level one need not account for neck length in evaluating VEMP latency. The intra-subject variability of norms can be enhanced if the normative data for VEMP characteristic parameters take structural variance into account. This study suggests that the adult range of VEMP latencies can be anticipated if neck length is >15.3 cm.

Role of multisensory stimuli in vigilance enhancement- a single trial event related potential study.

PubMed

Abbasi, Nida Itrat; Bodala, Indu Prasad; Bezerianos, Anastasios; Yu Sun; Al-Nashash, Hasan; Thakor, Nitish V

2017-07-01

Development of interventions to prevent vigilance decrement has important applications in sensitive areas like transportation and defence. The objective of this work is to use multisensory (visual and haptic) stimuli for cognitive enhancement during mundane tasks. Two different epoch intervals representing sensory perception and motor response were analysed using minimum variance distortionless response (MVDR) based single trial ERP estimation to understand the performance dependency on both factors. Bereitschaftspotential (BP) latency L3 (r=0.6 in phase 1 (visual) and r=0.71 in phase 2 (visual and haptic)) was significantly correlated with reaction time as compared to that of sensory ERP latency L2 (r=0.1 in both phase 1 and phase 2). This implies that low performance in monotonous tasks is predominantly dependent on the prolonged neural interaction with the muscles to initiate movement. Further, negative relationship was found between the ERP latencies related to sensory perception and Bereitschaftspotential (BP) and occurrence of epochs when multisensory cues are provided. This means that vigilance decrement is reduced with the help of multisensory stimulus presentation in prolonged monotonous tasks.

Auditory brain stem response and cortical evoked potentials in children with type 1 diabetes mellitus.

PubMed

Radwan, Heba Mohammed; El-Gharib, Amani Mohamed; Erfan, Adel Ali; Emara, Afaf Ahmad

2017-05-01

Delay in ABR and CAEPs wave latencies in children with type 1DM indicates that there is abnormality in the neural conduction in DM patients. The duration of DM has greater effect on auditory function than the control of DM. Diabetes mellitus (DM) is a common endocrine and metabolic disorder. Evoked potentials offer the possibility to perform a functional evaluation of neural pathways in the central nervous system. To investigate the effect of type 1 diabetes mellitus (T1DM) on auditory brain stem response (ABR) and cortical evoked potentials (CAEPs). This study included two groups: a control group (GI), which consisted of 20 healthy children with normal peripheral hearing, and a study group (GII), which consisted of 30 children with type I DM. Basic audiological evaluation, ABR, and CAEPs were done in both groups. Delayed absolute latencies of ABR and CAEPs waves were found. Amplitudes showed no significant difference between both groups. Positive correlation was found between ABR wave latencies and duration of DM. No correlation was found between ABR, CAEPs, and glycated hemoglobin.

Cognition and balance control: does processing of explicit contextual cues of impending perturbations modulate automatic postural responses?

PubMed

Coelho, Daniel Boari; Teixeira, Luis Augusto

2017-08-01

Processing of predictive contextual cues of an impending perturbation is thought to induce adaptive postural responses. Cueing in previous research has been provided through repeated perturbations with a constant foreperiod. This experimental strategy confounds explicit predictive cueing with adaptation and non-specific properties of temporal cueing. Two experiments were performed to assess those factors separately. To perturb upright balance, the base of support was suddenly displaced backwards in three amplitudes: 5, 10 and 15 cm. In Experiment 1, we tested the effect of cueing the amplitude of the impending postural perturbation by means of visual signals, and the effect of adaptation to repeated exposures by comparing block versus random sequences of perturbation. In Experiment 2, we evaluated separately the effects of cueing the characteristics of an impending balance perturbation and cueing the timing of perturbation onset. Results from Experiment 1 showed that the block sequence of perturbations led to increased stability of automatic postural responses, and modulation of magnitude and onset latency of muscular responses. Results from Experiment 2 showed that only the condition cueing timing of platform translation onset led to increased balance stability and modulation of onset latency of muscular responses. Conversely, cueing platform displacement amplitude failed to induce any effects on automatic postural responses in both experiments. Our findings support the interpretation of improved postural responses via optimized sensorimotor processes, at the same time that cast doubt on the notion that cognitive processing of explicit contextual cues advancing the magnitude of an impending perturbation can preset adaptive postural responses.

Synaptic physiology of the flow of information in the cat's visual cortex in vivo

PubMed Central

Hirsch, Judith A; Martinez, Luis M; Alonso, José-Manuel; Desai, Komal; Pillai, Cinthi; Pierre, Carhine

2002-01-01

Each stage of the striate cortical circuit extracts novel information about the visual environment. We asked if this analytic process reflected laminar variations in synaptic physiology by making whole-cell recording with dye-filled electrodes from the cat's visual cortex and thalamus; the stimuli were flashed spots. Thalamic afferents terminate in layer 4, which contains two types of cell, simple and complex, distinguished by the spatial structure of the receptive field. Previously, we had found that the postsynaptic and spike responses of simple cells reliably followed the time course of flash-evoked thalamic activity. Here we report that complex cells in layer 4 (or cells intermediate between simple and complex) similarly reprised thalamic activity (response/trial, 99 ± 1.9 %; response duration 159 ± 57 ms; latency 25 ± 4 ms; average ± standard deviation; n = 7). Thus, all cells in layer 4 share a common synaptic physiology that allows secure integration of thalamic input. By contrast, at the second cortical stage (layer 2+3), where layer 4 directs its output, postsynaptic responses did not track simple patterns of antecedent activity. Typical responses to the static stimulus were intermittent and brief (response/trial, 31 ± 40 %; response duration 72 ± 60 ms, latency 39 ± 7 ms; n = 11). Only richer stimuli like those including motion evoked reliable responses. All told, the second level of cortical processing differs markedly from the first. At that later stage, ascending information seems strongly gated by connections between cortical neurons. Inputs must be combined in newly specified patterns to influence intracortical stages of processing. PMID:11927691

Close similarity between spatiotemporal frequency tunings of human cortical responses and involuntary manual following responses to visual motion.

PubMed

Amano, Kaoru; Kimura, Toshitaka; Nishida, Shin'ya; Takeda, Tsunehiro; Gomi, Hiroaki

2009-02-01

Human brain uses visual motion inputs not only for generating subjective sensation of motion but also for directly guiding involuntary actions. For instance, during arm reaching, a large-field visual motion is quickly and involuntarily transformed into a manual response in the direction of visual motion (manual following response, MFR). Previous attempts to correlate motion-evoked cortical activities, revealed by brain imaging techniques, with conscious motion perception have resulted only in partial success. In contrast, here we show a surprising degree of similarity between the MFR and the population neural activity measured by magnetoencephalography (MEG). We measured the MFR and MEG induced by the same motion onset of a large-field sinusoidal drifting grating with changing the spatiotemporal frequency of the grating. The initial transient phase of these two responses had very similar spatiotemporal tunings. Specifically, both the MEG and MFR amplitudes increased as the spatial frequency was decreased to, at most, 0.05 c/deg, or as the temporal frequency was increased to, at least, 10 Hz. We also found in peak latency a quantitative agreement (approximately 100-150 ms) and correlated changes against spatiotemporal frequency changes between MEG and MFR. In comparison with these two responses, conscious visual motion detection is known to be most sensitive (i.e., have the lowest detection threshold) at higher spatial frequencies and have longer and more variable response latencies. Our results suggest a close relationship between the properties of involuntary motor responses and motion-evoked cortical activity as reflected by the MEG.

Repeated whisker stimulation evokes invariant neuronal responses in the dorsolateral striatum of anesthetized rats: a potential correlate of sensorimotor habits

PubMed Central

Mowery, Todd M.; Harrold, Jon B.

2011-01-01

The dorsolateral striatum (DLS) receives extensive projections from primary somatosensory cortex (SI), but very few studies have used somesthetic stimulation to characterize the sensory coding properties of DLS neurons. In this study, we used computer-controlled whisker deflections to characterize the extracellular responses of DLS neurons in rats lightly anesthetized with isoflurane. When multiple whiskers were synchronously deflected by rapid back-and-forth movements, whisker-sensitive neurons in the DLS responded to both directions of movement. The latency and magnitude of these neuronal responses displayed very little variation with changes in the rate (2, 5, or 8 Hz) of whisker stimulation. Simultaneous recordings in SI barrel cortex and the DLS revealed important distinctions in the neuronal responses of these serially connected brain regions. In contrast to DLS neurons, SI neurons were activated by the initial deflection of the whiskers but did not respond when the whiskers moved back to their original position. As the rate of whisker stimulation increased, SI responsiveness declined, and the latencies of the responses increased. In fact, when whiskers were deflected at 5 or 8 Hz, many neurons in the DLS responded before the SI neurons. These results and earlier anatomic findings suggest that a component of the sensory-induced response in the DLS is mediated by inputs from the thalamus. Furthermore, the lack of sensory adaptation in the DLS may represent a critical part of the neural mechanism by which the DLS encodes stimulus-response associations that trigger motor habits and other stimulus-evoked behaviors that are not contingent on rewarded outcomes. PMID:21389309

Repeated whisker stimulation evokes invariant neuronal responses in the dorsolateral striatum of anesthetized rats: a potential correlate of sensorimotor habits.

PubMed

Mowery, Todd M; Harrold, Jon B; Alloway, Kevin D

2011-05-01

The dorsolateral striatum (DLS) receives extensive projections from primary somatosensory cortex (SI), but very few studies have used somesthetic stimulation to characterize the sensory coding properties of DLS neurons. In this study, we used computer-controlled whisker deflections to characterize the extracellular responses of DLS neurons in rats lightly anesthetized with isoflurane. When multiple whiskers were synchronously deflected by rapid back-and-forth movements, whisker-sensitive neurons in the DLS responded to both directions of movement. The latency and magnitude of these neuronal responses displayed very little variation with changes in the rate (2, 5, or 8 Hz) of whisker stimulation. Simultaneous recordings in SI barrel cortex and the DLS revealed important distinctions in the neuronal responses of these serially connected brain regions. In contrast to DLS neurons, SI neurons were activated by the initial deflection of the whiskers but did not respond when the whiskers moved back to their original position. As the rate of whisker stimulation increased, SI responsiveness declined, and the latencies of the responses increased. In fact, when whiskers were deflected at 5 or 8 Hz, many neurons in the DLS responded before the SI neurons. These results and earlier anatomic findings suggest that a component of the sensory-induced response in the DLS is mediated by inputs from the thalamus. Furthermore, the lack of sensory adaptation in the DLS may represent a critical part of the neural mechanism by which the DLS encodes stimulus-response associations that trigger motor habits and other stimulus-evoked behaviors that are not contingent on rewarded outcomes.

VEMP responses are not affected in non-insulin-dependent diabetes mellitus patients with or without polyneuropathy.

PubMed

Bektas, Devrim; Gazioglu, Sibel; Arslan, Selcuk; Cobanoglu, Bengu; Boz, Cavit; Caylan, Refik

2008-07-01

Vestibular evoked myogenic responses (VEMPs) are not affected in non-insulin-dependent diabetes mellitus (NIDDM) patients with or without polyneuropathy. To compare VEMP responses of NIDDM patients and healthy subjects. VEMP responses were collected from 25 NIDDM patients with polyneuropathy (PNP), 13 NIDDM patients without PNP and 21 healthy subjects using click stimulation. After excluding ears with hearing loss (HL) (worse than 25 dB) the VEMP responses (p13 and n21 latencies and amplitude) recorded in 105 dB stimulus intensity were compared. There was no statistically significant difference between groups. VEMP responses were found to be normal in NIDDM patients with or without PNP.

Cortisol and salivary alpha-amylase trajectories following a group social-evaluative stressor with adolescents.

PubMed

Katz, Deirdre A; Peckins, Melissa K

2017-12-01

Intraindividual variability in stress responsivity and the interrelationship of multiple neuroendocrine systems make a multisystem analytic approach to examining the human stress response challenging. The present study makes use of an efficient social-evaluative stress paradigm - the Group Public Speaking Task for Adolescents (GPST-A) - to examine the hypothalamic-pituitary-adrenocortical (HPA)-axis and Autonomic Nervous System (ANS) reactivity profiles of 54 adolescents with salivary cortisol and salivary alpha-amylase (sAA). First, we account for individuals' time latency of hormone concentrations between individuals. Second, we use a two-piece multilevel growth curve model with landmark registration to examine the reactivity and recovery periods of the stress response separately. This analytic approach increases the models' sensitivity to detecting trajectory differences in the reactivity and recovery phases of the stress response and allows for interindividual variation in the timing of participants' peak response following a social-evaluative stressor. The GPST-A evoked typical cortisol and sAA responses in both males and females. Males' cortisol concentrations were significantly higher than females' during each phase of the response. We found no gender difference in the sAA response. However, the rate of increase in sAA as well as overall sAA secretion across the study were associated with steeper rates of cortisol reactivity and recovery. This study demonstrates a way to model the response trajectories of salivary biomarkers of the HPA-axis and ANS when taking a multisystem approach to neuroendocrine research that enables researchers to make conclusions about the reactivity and recovery phases of the HPA-axis and ANS responses. As the study of the human stress response progresses toward a multisystem analytic approach, it is critical that individual variability in peak latency be taken into consideration and that accurate modeling techniques capture individual variability in the stress response so that accurate conclusions can be made about separate phases of the response. Copyright © 2017 Elsevier Ltd. All rights reserved.

Peripheral and central determinants of a nociceptive reaction: an approach to psychophysics in the rat.

PubMed

Benoist, Jean-Michel; Pincedé, Ivanne; Ballantyne, Kay; Plaghki, Léon; Le Bars, Daniel

2008-09-03

The quantitative end-point for many behavioral tests of nociception is the reaction time, i.e. the time lapse between the beginning of the application of a stimulus, e.g. heat, and the evoked response. Since it is technically impossible to heat the skin instantaneously by conventional means, the question of the significance of the reaction time to radiant heat remains open. We developed a theoretical framework, a related experimental paradigm and a model to analyze in psychophysical terms the "tail-flick" responses of rats to random variations of noxious radiant heat. A CO(2) laser was used to avoid the drawbacks associated with standard methods of thermal stimulation. Heating of the skin was recorded with an infrared camera and was stopped by the reaction of the animal. For the first time, we define and determine two key descriptors of the behavioral response, namely the behavioral threshold (Tbeta) and the behavioral latency (Lbeta). By employing more than one site of stimulation, the paradigm allows determination of the conduction velocity of the peripheral fibers that trigger the response (V) and an estimation of the latency (Ld) of the central decision-making process. Ld (approximately 130 ms) is unaffected by ambient or skin temperature changes that affect the behavioral threshold (approximately 42.2-44.9 degrees C in the 20-30 degrees C range), behavioral latency (<500 ms), and the conduction velocity of the peripheral fibers that trigger the response (approximately 0.35-0.76 m/s in the 20-30 degrees C range). We propose a simple model that is verified experimentally and that computes the variations in the so-called "tail-flick latency" (TFL) caused by changes in either the power of the radiant heat source, the initial temperature of the skin, or the site of stimulation along the tail. This approach enables the behavioral determinations of latent psychophysical (Tbeta, Lbeta, Ld) and neurophysiological (V) variables that have been previously inaccessible with conventional methods. Such an approach satisfies the repeated requests for improving nociceptive tests and offers a potentially heuristic progress for studying nociceptive behavior on more firm physiological and psychophysical grounds. The validity of using a reaction time of a behavioral response to an increasing heat stimulus as a "pain index" is challenged. This is illustrated by the predicted temperature-dependent variations of the behavioral TFL elicited by spontaneous variations of the temperature of the tail for thermoregulation.

Near-Miss Effects on Response Latencies and Win Estimations of Slot Machine Players

ERIC Educational Resources Information Center

Dixon, Mark R.; Schreiber, James E.

2004-01-01

The present study examined the degree to which slot machine near-miss trials, or trials that displayed 2 of 3 winning symbols on the payoff line, affected response times and win estimations of 12 recreational slot machine players. Participants played a commercial slot machine in a casino-like laboratory for course extra-credit points. Videotaped…

EXPERIMENTAL ANALYSIS OF THE CONTROL OF SPEECH PRODUCTION AND PERCEPTION. PROGRESS REPORT NO. I, FEBRUARY 1--SEPTEMBER 1, 1961.

ERIC Educational Resources Information Center

LANE, HARLAN; AND OTHERS

THIS DOCUMENT IS THE FIRST IN A SERIES REPORTING ON PROGRESS OF AN EXPERIMENTAL RESEARCH PROGRAM IN SPEECH CONTROL. THE TOPICS DISCUSSED ARE--(1) THE DISCONTINUITY OF AUDITORY DISCRIMINATION LEARNING IN HUMAN ADULTS, (2) DISCRIMINATIVE CONTROL OF CONCURRENT RESPONSES--THE RELATIONS AMONG RESPONSE FREQUENCY, LATENCY, AND TOPOGRAPHY IN AUDITORY…

[Effect of the middle ear status on the recording of vestibular evoked myogenic potential--VEMP].

PubMed

Kurzyna, Agnieszka; Hassmann-Poznańska, Elzbieta; Topolska, Małgorzata Maria

2005-01-01

The aim of this study was to assess the effect of the middle ear status on the recording of air- and bone-conducted vestibular evoked myogenic potential. Forty eight children were included in the study, ranging in age from 4 to 10 years. All of the children underwent otoscopy, pure tone audiometry, tympanometry and air- and bone-conducted VEMP in response to click. There were 3 groups according to the condition of the middle ear: group I--52 ears (type A and C1 tympanogram, pure tone average < or = 20 dB), group II--23 ears (type C2 and B tympanogram, pure tone average < or = 20 dB), group III--21 (type B tympanogram, pure tone average > 20 dB). The threshold, presence of correct waveform morphology of the response and latency was evaluated. The condition of the middle ear has no significant effect on the recording of VEMP and mean level of the response threshold with bone stimulation, based on the performed studies. However, with air stimulation it has effect on the recording of VEMP, increase of the mean threshold response and shortening of latency p13 and n23.

Responses evoked from man by acoustic stimulation

NASA Technical Reports Server (NTRS)

Galambos, R.; Hecox, K.; Picton, T.

1974-01-01

Clicks and other acoustic stimuli evoke time-locked responses from the brain of man. The properties of the waves recordable within the interval from 1 to 10 msec after the stimuli strike the eardrum are discussed along with factors influencing the waves in the 100 to 500 msec epoch. So-called brainstem responses from a normal young adult are considered. No waves were observed for clicks to weak to be heard. With increasing stimulus strength the waves become larger in amplitude and their latency shortens.

The Role of Habituation and Sensitization in Understanding the Annoyance of Community Exposures to Impulsive Noise

DTIC Science & Technology

2009-05-15

an orienting re- sponse followed by a defense response at 64 dBA ( impulse ). The 80 dB ERDC/CERL TR-09-14 25 impulses produced by the small firearm...literature, shorter response latencies are generally attributed to a greater degree of arousal. With impulsive sounds repeated in rapid succession...ERDC–CERL, SERDP-funded project focusing on evaluating responses to military noise. The research team’s decision was based on time burden

Central and peripheral components of short latency vestibular responses in the chicken

NASA Technical Reports Server (NTRS)

Nazareth, A. M.; Jones, T. A.

1998-01-01

Far-field recordings of short latency vestibular responses to pulsed cranial translation are composed of a series of positive and negative peaks occurring within 10 ms following stimulus onset. In the bird, these vestibular evoked potentials (VsEPs) can be recorded noninvasively and have been shown in the chicken and quail to depend strictly upon the activation of the vestibular component of the eighth nerve. The utility of the VsEP in the study of vestibular systems is dependent upon a clear understanding of the neural sources of response components. The primary aim of the current research in the chicken was to critically test the hypotheses that 1) responses are generated by both peripheral and central neurons and 2) peaks P1 and N1 originate from first order vestibular neurons, whereas later waves primarily depend on activity in higher order neurons. The principal strategy used here was to surgically isolate the eighth nerve as it enters the brainstem. Interruption of primary afferents of the eighth nerve in the brainstem substantially reduced or eliminated peaks beyond P2, whereas P1 and N1 were generally spared. Surgical sections that spared vestibular pathways had little effect on responses. The degree of change in response components beyond N1 was correlated with the extent of damage to central vestibular relays. These findings support the conclusion that responses are produced by both peripheral and central elements of the vestibular system. Further, response peaks later than N1 appear to be dependent upon central relays, whereas P1 and N1 reflect activity of the peripheral nerve. These findings clarify the roles of peripheral and central neurons in the generation of vestibular evoked potentials and provide the basis for a more useful and detailed interpretation of data from vestibular response testing.

Monitoring auditory cortical plasticity in hearing aid users with long latency auditory evoked potentials: a longitudinal study.

PubMed

Leite, Renata Aparecida; Magliaro, Fernanda Cristina Leite; Raimundo, Jeziela Cristina; Bento, Ricardo Ferreira; Matas, Carla Gentile

2018-02-19

The objective of this study was to compare long-latency auditory evoked potentials before and after hearing aid fittings in children with sensorineural hearing loss compared with age-matched children with normal hearing. Thirty-two subjects of both genders aged 7 to 12 years participated in this study and were divided into two groups as follows: 14 children with normal hearing were assigned to the control group (mean age 9 years and 8 months), and 18 children with mild to moderate symmetrical bilateral sensorineural hearing loss were assigned to the study group (mean age 9 years and 2 months). The children underwent tympanometry, pure tone and speech audiometry and long-latency auditory evoked potential testing with speech and tone burst stimuli. The groups were assessed at three time points. The study group had a lower percentage of positive responses, lower P1-N1 and P2-N2 amplitudes (speech and tone burst), and increased latencies for the P1 and P300 components following the tone burst stimuli. They also showed improvements in long-latency auditory evoked potentials (with regard to both the amplitude and presence of responses) after hearing aid use. Alterations in the central auditory pathways can be identified using P1-N1 and P2-N2 amplitude components, and the presence of these components increases after a short period of auditory stimulation (hearing aid use). These findings emphasize the importance of using these amplitude components to monitor the neuroplasticity of the central auditory nervous system in hearing aid users.

Monitoring auditory cortical plasticity in hearing aid users with long latency auditory evoked potentials: a longitudinal study

PubMed Central

Leite, Renata Aparecida; Magliaro, Fernanda Cristina Leite; Raimundo, Jeziela Cristina; Bento, Ricardo Ferreira; Matas, Carla Gentile

2018-01-01

OBJECTIVE: The objective of this study was to compare long-latency auditory evoked potentials before and after hearing aid fittings in children with sensorineural hearing loss compared with age-matched children with normal hearing. METHODS: Thirty-two subjects of both genders aged 7 to 12 years participated in this study and were divided into two groups as follows: 14 children with normal hearing were assigned to the control group (mean age 9 years and 8 months), and 18 children with mild to moderate symmetrical bilateral sensorineural hearing loss were assigned to the study group (mean age 9 years and 2 months). The children underwent tympanometry, pure tone and speech audiometry and long-latency auditory evoked potential testing with speech and tone burst stimuli. The groups were assessed at three time points. RESULTS: The study group had a lower percentage of positive responses, lower P1-N1 and P2-N2 amplitudes (speech and tone burst), and increased latencies for the P1 and P300 components following the tone burst stimuli. They also showed improvements in long-latency auditory evoked potentials (with regard to both the amplitude and presence of responses) after hearing aid use. CONCLUSIONS: Alterations in the central auditory pathways can be identified using P1-N1 and P2-N2 amplitude components, and the presence of these components increases after a short period of auditory stimulation (hearing aid use). These findings emphasize the importance of using these amplitude components to monitor the neuroplasticity of the central auditory nervous system in hearing aid users. PMID:29466495

Fentanyl produces an anti-hyperalgesic effect through the suppression of sodium channels in mice with painful diabetic neuropathy.

PubMed

Tanaka, Ken-ichiro; Nakanishi, Yuki; Sekino, Shyota; Ikegami, Megumi; Ikeda, Hiroko; Kamei, Junzo

2014-06-15

Diabetic neuropathy is one of the most frequent complications of diabetes mellitus. Therefore, the present study was designed to investigate the anti-hyperalgesic mechanism of fentanyl in a mouse model of streptozotocin-induced diabetic neuropathy. The antinociceptive response was assessed by recording the latency in a tail-flick test. The tail-flick latency in diabetic mice was significantly shorter than that in non-diabetic mice. Fentanyl, at doses of 3 and 10 μg/kg, s.c., produced a dose-dependent increase in the tail-flick latencies in diabetic mice. While fentanyl (3 μg/kg, s.c.) did not produce a significant inhibition of the tail-flick response in non-diabetic mice, it significantly prolonged the tail-flick latency in diabetic mice to the same level as the baseline latency in non-diabetic mice. Although pretreatment with naloxone (3mg/kg, s.c.) completely antagonized fentanyl-induced antinociception in non-diabetic mice, it had no effect on the antinociceptive effect of fentanyl in diabetic mice. Pretreatment with either of the voltage-gated sodium channel openers fenvarelarte and veratridine practically abolished the antinociceptive effects of fentanyl in diabetic mice. However, neither fenvarelate nor veratridine affected the antinociceptive effect of fentanyl in non-diabetic mice. These results suggest that the anti-hyperalgesic effect of fentanyl is mediated through the blockade of sodium channels in diabetic mice, whereas opioid receptors mediate the antinociceptive effect of fentanyl in non-diabetic mice. Copyright © 2014 Elsevier B.V. All rights reserved.

Asymmetry of temporal auditory T-complex: right ear-left hemisphere advantage in Tb timing in children.

PubMed

Bruneau, Nicole; Bidet-Caulet, Aurélie; Roux, Sylvie; Bonnet-Brilhault, Frédérique; Gomot, Marie

2015-02-01

To investigate brain asymmetry of the temporal auditory evoked potentials (T-complex) in response to monaural stimulation in children compared to adults. Ten children (7 to 9 years) and ten young adults participated in the study. All were right-handed. The auditory stimuli used were tones (1100 Hz, 70 dB SPL, 50 ms duration) delivered monaurally (right, left ear) at four different levels of stimulus onset asynchrony (700-1100-1500-3000 ms). Latency and amplitude of responses were measured at left and right temporal sites according to the ear stimulated. Peaks of the three successive deflections (Na-Ta-Tb) of the T-complex were greater in amplitude and better defined in children than in adults. Amplitude measurements in children indicated that Na culminates on the left hemisphere whatever the ear stimulated whereas Ta and Tb culminate on the right hemisphere but for left ear stimuli only. Peak latency displayed different patterns of asymmetry. Na and Ta displayed shorter latencies for contralateral stimulation. The original finding was that Tb peak latency was the shortest at the left temporal site for right ear stimulation in children. Amplitude increased and/or peak latency decreased with increasing SOA, however no interaction effect was found with recording site or with ear stimulated. Our main original result indicates a right ear-left hemisphere timing advantage for Tb peak in children. The Tb peak would therefore be a good candidate as an electrophysiological marker of ear advantage effects during dichotic stimulation and of functional inter-hemisphere interactions and connectivity in children. Copyright © 2014. Published by Elsevier B.V.

Auditory evoked responses to binaural beat illusion: stimulus generation and the derivation of the Binaural Interaction Component (BIC).

PubMed

Ozdamar, Ozcan; Bohorquez, Jorge; Mihajloski, Todor; Yavuz, Erdem; Lachowska, Magdalena

2011-01-01

Electrophysiological indices of auditory binaural beats illusions are studied using late latency evoked responses. Binaural beats are generated by continuous monaural FM tones with slightly different ascending and descending frequencies lasting about 25 ms presented at 1 sec intervals. Frequency changes are carefully adjusted to avoid any creation of abrupt waveform changes. Binaural Interaction Component (BIC) analysis is used to separate the neural responses due to binaural involvement. The results show that the transient auditory evoked responses can be obtained from the auditory illusion of binaural beats.

Mechanical Conflict System: A Novel Operant Method for the Assessment of Nociceptive Behavior

PubMed Central

Harte, Steven E.; Meyers, Jessica B.; Donahue, Renee R.; Taylor, Bradley K.; Morrow, Thomas J.

2016-01-01

A new operant test for preclinical pain research, termed the Mechanical Conflict System (MCS), is presented. Rats were given a choice either to remain in a brightly lit compartment or to escape to a dark compartment by crossing an array of height-adjustable nociceptive probes. Latency to escape the light compartment was evaluated with varying probe heights (0, .5, 1, 2, 3, and 4 mm above compartment floor) in rats with neuropathic pain induced by constriction nerve injury (CCI) and in naive control rats. Escape responses in CCI rats were assessed following intraperitoneal administration of pregabalin (10 and 30 mg/kg), morphine (2.5 and 5 mg/kg), and the tachykinin NK1 receptor antagonist, RP 67580 (1 and 10 mg/kg). Results indicate that escape latency increased as a function of probe height in both naive and CCI rats. Pregabalin (10 and 30 mg/kg) and morphine (5 mg/kg), but not RP 67580, decreased latency to escape in CCI rats suggesting an antinociceptive effect. In contrast, morphine (10 mg/kg) but not pregabalin (30 mg/kg) increased escape latency in naive rats suggesting a possible anxiolytic action of morphine in response to light-induced fear. No order effects following multiple test sessions were observed. We conclude that the MCS is a valid method to assess behavioral signs of affective pain in rodents. PMID:26915030

Effects of the acute exposure to the electromagnetic field of mobile phones on human auditory brainstem responses.

PubMed

Oysu, Cagatay; Topak, Murat; Celik, Oner; Yilmaz, H Baki; Sahin, A Asli

2005-10-01

The purpose of this study was to evaluate the short-term effects of the electromagnetic fields (EMF) of mobile phones on human auditory brainstem responses. This prospective study of healthy adults evaluated the influence of EMF. Eighteen healthy adult volunteers participated in this study. Mobile telephones emitting signals in the region of 900 MHz and with the highest SAR value of 0.82 W/kg were positioned in direct contact to the right ear, which was exposed to the phone signal for 15 min before and after ABR testing with click stimuli of 60 and 80 dB nHL intensities. The latencies of the waves and interwave latencies were measured on screen by an experienced audiologist. The differences of the mean latencies of waves I, III and IV were not significant in initial and post-exposure ABR measurements at both 60 and 80 dB nHL stimulus levels ( P >0.05). Similarly, differences of the mean interwave intervals I-III, I-V and III-V remained insignificant at the initial and postexposure ABR measurements at stimulus levels of both 60 and 80 dB nHL ( P >0.05). Acute exposure to the EMF of mobile phones does not cause perturbations in ABR latencies. However, these negative results should not encourage excessive mobile communication, because minor biological and neurophysiological influences may not be detectable by the current technology.

Do resting brain dynamics predict oddball evoked-potential?

PubMed Central

2011-01-01

Background The oddball paradigm is widely applied to the investigation of cognitive function in neuroscience and in neuropsychiatry. Whether cortical oscillation in the resting state can predict the elicited oddball event-related potential (ERP) is still not clear. This study explored the relationship between resting electroencephalography (EEG) and oddball ERPs. The regional powers of 18 electrodes across delta, theta, alpha and beta frequencies were correlated with the amplitude and latency of N1, P2, N2 and P3 components of oddball ERPs. A multivariate analysis based on partial least squares (PLS) was applied to further examine the spatial pattern revealed by multiple correlations. Results Higher synchronization in the resting state, especially at the alpha spectrum, is associated with higher neural responsiveness and faster neural propagation, as indicated by the higher amplitude change of N1/N2 and shorter latency of P2. None of the resting quantitative EEG indices predict P3 latency and amplitude. The PLS analysis confirms that the resting cortical dynamics which explains N1/N2 amplitude and P2 latency does not show regional specificity, indicating a global property of the brain. Conclusions This study differs from previous approaches by relating dynamics in the resting state to neural responsiveness in the activation state. Our analyses suggest that the neural characteristics carried by resting brain dynamics modulate the earlier/automatic stage of target detection. PMID:22114868

Intracortical circuits amplify sound-evoked activity in primary auditory cortex following systemic injection of salicylate in the rat

PubMed Central

Chrostowski, Michael; Salvi, Richard J.; Allman, Brian L.

2012-01-01

A high dose of sodium salicylate temporarily induces tinnitus, mild hearing loss, and possibly hyperacusis in humans and other animals. Salicylate has well-established effects on cochlear function, primarily resulting in the moderate reduction of auditory input to the brain. Despite decreased peripheral sensitivity and output, salicylate induces a paradoxical enhancement of the sound-evoked field potential at the level of the primary auditory cortex (A1). Previous electrophysiologic studies have begun to characterize changes in thalamorecipient layers of A1; however, A1 is a complex neural circuit with recurrent intracortical connections. To describe the effects of acute systemic salicylate treatment on both thalamic and intracortical sound-driven activity across layers of A1, we applied current-source density (CSD) analysis to field potentials sampled across cortical layers in the anesthetized rat. CSD maps were normally characterized by a large, short-latency, monosynaptic, thalamically driven sink in granular layers followed by a lower amplitude, longer latency, polysynaptic, intracortically driven sink in supragranular layers. Following systemic administration of salicylate, there was a near doubling of both granular and supragranular sink amplitudes at higher sound levels. The supragranular sink amplitude input/output function changed from becoming asymptotic at approximately 50 dB to sharply nonasymptotic, often dominating the granular sink amplitude at higher sound levels. The supragranular sink also exhibited a significant decrease in peak latency, reflecting an acceleration of intracortical processing of the sound-evoked response. Additionally, multiunit (MU) activity was altered by salicylate; the normally onset/sustained MU response type was transformed into a primarily onset response type in granular and infragranular layers. The results from CSD analysis indicate that salicylate significantly enhances sound-driven response via intracortical circuits. PMID:22496535

A convergent and essential interneuron pathway for Mauthner-cell-mediated escapes.

PubMed

Lacoste, Alix M B; Schoppik, David; Robson, Drew N; Haesemeyer, Martin; Portugues, Ruben; Li, Jennifer M; Randlett, Owen; Wee, Caroline L; Engert, Florian; Schier, Alexander F

2015-06-01

The Mauthner cell (M-cell) is a command-like neuron in teleost fish whose firing in response to aversive stimuli is correlated with short-latency escapes [1-3]. M-cells have been proposed as evolutionary ancestors of startle response neurons of the mammalian reticular formation [4], and studies of this circuit have uncovered important principles in neurobiology that generalize to more complex vertebrate models [3]. The main excitatory input was thought to originate from multisensory afferents synapsing directly onto the M-cell dendrites [3]. Here, we describe an additional, convergent pathway that is essential for the M-cell-mediated startle behavior in larval zebrafish. It is composed of excitatory interneurons called spiral fiber neurons, which project to the M-cell axon hillock. By in vivo calcium imaging, we found that spiral fiber neurons are active in response to aversive stimuli capable of eliciting escapes. Like M-cell ablations, bilateral ablations of spiral fiber neurons largely eliminate short-latency escapes. Unilateral spiral fiber neuron ablations shift the directionality of escapes and indicate that spiral fiber neurons excite the M-cell in a lateralized manner. Their optogenetic activation increases the probability of short-latency escapes, supporting the notion that spiral fiber neurons help activate M-cell-mediated startle behavior. These results reveal that spiral fiber neurons are essential for the function of the M-cell in response to sensory cues and suggest that convergent excitatory inputs that differ in their input location and timing ensure reliable activation of the M-cell, a feedforward excitatory motif that may extend to other neural circuits. Copyright © 2015 Elsevier Ltd. All rights reserved.

Reflexive contraction of the levator palpebrae superioris muscle to involuntarily sustain the effective eyelid retraction through the transverse trigeminal proprioceptive nerve on the proximal Mueller's muscle: verification with evoked electromyography.

PubMed

Ban, Ryokuya; Matsuo, Kiyoshi; Osada, Yoshiro; Ban, Midori; Yuzuriha, Shunsuke

2010-01-01

We have proposed a hypothetical mechanism to involuntarily sustain the effective eyelid retraction, which consists of not only voluntary but also reflexive contractions of the levator palpebrae superior muscle (LPSM). Voluntary contraction of fast-twitch fibres of the LPSM stretches the mechanoreceptors in Mueller's muscle to evoke trigeminal proprioception, which induces continuous reflexive contraction of slow-twitch fibres of the LPSM through the trigeminal proprioceptive nerve fibres innervating the mechanoreceptors in Mueller's muscle via the oculomotor neurons, as a tonic trigemino-oculomotor reflex. In the common skeletal mixed muscles, electrical stimulation of the proprioceptive nerve, which apparently connects the mechanoreceptors in muscle spindles to the motoneurons, induces the electromyographic response as the Hoffmann reflex. To verify the presence of the trigemino-oculomotor reflex, we confirmed whether intra-operative electrical simulation of the transverse trigeminal proprioceptive nerve on the proximal Mueller's muscle evokes an electromyographic response in the LPSM under general anaesthesia in 12 patients. An ipsilateral, phasic, short-latency response (latency: 2.8+/-0.3 ms) was induced in the ipsilateral LPSM in 10 of 12 subjects. As successful induction of the short-latency response in the ipsilateral LPSM corresponds to the Hoffmann reflex in the common skeletal mixed muscles, the present study is the first electromyographic verification of the presence of the monosynaptic trigemino-oculomotor reflex to induce reflexive contraction of the LPSM. The presence of the trigemino-oculomotor reflex may elucidate the unexplainable blepharoptosis due to surgery, trauma and tumour, all of which may damage the trigeminal proprioceptive nerve fibres to impair the trigemino-oculomotor reflex. Copyright (c) 2008. Published by Elsevier Ltd.

Auditory-visual integration modulates location-specific repetition suppression of auditory responses.

PubMed

Shrem, Talia; Murray, Micah M; Deouell, Leon Y

2017-11-01

Space is a dimension shared by different modalities, but at what stage spatial encoding is affected by multisensory processes is unclear. Early studies observed attenuation of N1/P2 auditory evoked responses following repetition of sounds from the same location. Here, we asked whether this effect is modulated by audiovisual interactions. In two experiments, using a repetition-suppression paradigm, we presented pairs of tones in free field, where the test stimulus was a tone presented at a fixed lateral location. Experiment 1 established a neural index of auditory spatial sensitivity, by comparing the degree of attenuation of the response to test stimuli when they were preceded by an adapter sound at the same location versus 30° or 60° away. We found that the degree of attenuation at the P2 latency was inversely related to the spatial distance between the test stimulus and the adapter stimulus. In Experiment 2, the adapter stimulus was a tone presented from the same location or a more medial location than the test stimulus. The adapter stimulus was accompanied by a simultaneous flash displayed orthogonally from one of the two locations. Sound-flash incongruence reduced accuracy in a same-different location discrimination task (i.e., the ventriloquism effect) and reduced the location-specific repetition-suppression at the P2 latency. Importantly, this multisensory effect included topographic modulations, indicative of changes in the relative contribution of underlying sources across conditions. Our findings suggest that the auditory response at the P2 latency is affected by spatially selective brain activity, which is affected crossmodally by visual information. © 2017 Society for Psychophysiological Research.

Effect of squatting velocity on hip muscle latency in women with patellofemoral pain syndrome.

PubMed

Orozco-Chavez, Ignacio; Mendez-Rebolledo, Guillermo

2018-03-01

[Purpose] Neuromuscular activity has been evaluated in patellofemoral pain syndrome but movement velocity has not been considered. The aim was to determine differences in onset latency of hip and knee muscles between individuals with and without patellofemoral pain syndrome during a single leg squat, and whether any differences are dependent on movement velocity. [Subjects and Methods] Twenty-four females with patellofemoral pain syndrome and 24 healthy females participated. Onset latency of gluteus maximus, anterior and posterior gluteus medius, rectus femoris, vastus medialis, vastus lateralis and biceps femoris during a single leg squat at high and low velocity were evaluated. [Results] There was an interaction between velocity and diagnosis for posterior gluteus medius. Healthy subjects showed a later posterior gluteus medius onset latency at low velocity than high velocity; and also later than patellofemoral pain syndrome subjects at low velocity and high velocity. [Conclusion] Patellofemoral pain syndrome subjects presented an altered latency of posterior gluteus medius during a single leg squat and did not generate adaptations to velocity variation, while healthy subjects presented an earlier onset latency in response to velocity increase.

House sparrows' (Passer domesticus) behaviour in a novel environment is modulated by social context and familiarity in a sex-specific manner.

PubMed

Tuliozi, Beniamino; Fracasso, Gerardo; Hoi, Herbert; Griggio, Matteo

2018-01-01

Exploratory behaviour is one of the best-investigated behavioural traits. However, little is known about how differences in familiarity, i.e. in the knowledge and previous experience with a companion can influence the exploration of a novel environment. However, to our knowledge, such a critical feature of the social environment has never been the target of a study relating it to exploratory behaviour in birds. Here we examined if familiarity with a conspecific could affect behavioural responses of individuals confronted with a novel environment. We recorded the latency to land on the ground, latency to feed, time spent feeding and number of sectors visited of 48 female and 48 male house sparrows ( Passer domesticus ) in an indoor aviary in three contexts: alone (individual context), with an unfamiliar and with a familiar same-sex companion. House sparrows landed sooner on the ground when in the familiar context than when in the individual context. Birds in unfamiliar pairs followed each other less than familiar birds, but this difference diminished with time spent exploring. Moreover, males and females differed in their behavioural responses in the unfamiliar context. Females with a familiar companion landed sooner than when they were paired with an unfamiliar conspecific, whereas only the presence of a companion but not familiarity reduced males latency to land on the ground. Finally, when considering the unfamiliar context males had shorter latencies to forage and thus spent more time eating than females. The presence or absence of a companion and its familiarity with the focal individual influenced differently the behavioural responses of male and female house sparrows in a novel environment. As house sparrows are strongly sociable, the influence of the social environment is likely to be of paramount importance to understand the selective pressures acting on them, particularly in recently colonized areas with ephemeral food sources. Our results shed light on the complex influence that the social environment has on the behavioural responses of a cosmopolitan bird.

[Origin of acoustically evoked short latency negative response in guinea pigs].

PubMed

Huang, Wen-qin; Qin, Huan-hua; Nong, Dong-xiao; Tang, An-zhou; Li, Zhi-mei; Yang, Tian

2011-04-01

To establish a model of acoustically evoked short latency negative response (ASNR) in guinea pigs, a model of profound hearing loss with normal saccular functions, and verify the correlation between ASNR and vestibular evoked myogenic potential (VEMP). Thirty-two healthy guinea pigs were employed in the experiment, which were randomly divided into control group (16 subjects) and deafened group (16 subjects). Each animal experienced auditory and vestibular tests including auditory brainstem response (ABR), VEMP and caloric test. A quick treatment was employed for deafened group consisting of a subcutaneous injection of kanamycin at a dose of 400 mg/kg followed by a jugular vein injection of ethacrynic acid at a dose of 40 mg/kg one hour later. The animals were received ABR, VEMP and caloric test 7 - 10 days following the drug administration. The deafened group was further divided into ASNR group and non-ASNR group, based on the presence of ASNR. In deafened group, five subjects died postoperatively, 11 subjects (22 ears) provided full data, ASNR was elicited in eight ears (36.4%), the threshold was 120 - 130 dB SPL with mean of (124.4 ± 4.96) dB SPL. Its latency range was 1.75 - 2.60 ms with mean of (2.15 ± 0.27) ms. The mean latency of threshold was (2.34 ± 0.18) ms. All eight ASNR ears presented with VEMP. The VEMP threshold, positive and negative potential latencies proved no statistical difference (P > 0.05) between ASNR group and control group. Significant difference was detected between the VEMP presence of ASNR group and non-ASNR group (P = 0.002). There was no statistically significant correlation between VEMP and caloric test neither between ASNR and caloric test in deafened group. This study evoked ASNR in an ototoxicity guinea pig model which has profound hearing loss with normal saccular functions. The presence of ASNR correlated with VEMP, however, not correlated with caloric test, suggesting that ASNR and VEMP are both originated from the saccule.

Breathing for answering: the time course of response planning in conversation

PubMed Central

Torreira, Francisco; Bögels, Sara; Levinson, Stephen C.

2015-01-01

We investigate the timing of pre-answer inbreaths in order to shed light on the time course of response planning and execution in conversational turn-taking. Using acoustic and inductive plethysmography recordings of seven dyadic conversations in Dutch, we show that pre-answer inbreaths in conversation typically begin briefly after the end of questions. We also show that the presence of a pre-answer inbreath usually co-occurs with substantially delayed answers, with a modal latency of 576 vs. 100 ms for answers not preceded by an inbreath. Based on previously reported minimal latencies for internal intercostal activation and the production of speech sounds, we propose that vocal responses, either in the form of a pre-utterance inbreath or of speech proper when an inbreath is not produced, are typically launched in reaction to information present in the last portion of the interlocutor's turn. We also show that short responses are usually made on residual breath, while longer responses are more often preceded by an inbreath. This relation of inbreaths to answer length suggests that by the time an inbreath is launched, typically during the last few hundred milliseconds of the question, the length of the answer is often prepared to some extent. Together, our findings are consistent with a two-stage model of response planning in conversational turn-taking: early planning of content often carried out in overlap with the incoming turn, and late launching of articulation based on the identification of turn-final cues. PMID:25814976

Attentional Modulation of Eye Torsion Responses

NASA Technical Reports Server (NTRS)

Stevenson, Scott B.; Mahadevan, Madhumitha S.; Mulligan, Jeffrey B.

2016-01-01

Eye movements generally have both reflexive and voluntary aspects, but torsional eye movements are usually thought of as a reflexive response to image rotation around the line of sight (torsional OKN) or to head roll (torsional VOR). In this study we asked whether torsional responses could be modulated by attention in a case where two stimuli rotated independently, and whether attention would influence the latency of responses. The display consisted of rear-projected radial "pinwheel" gratings, with an inner annulus segment extending from the center to 22 degrees eccentricity, and an outer annulus segment extending from 22 degrees out to 45 degrees eccentricity. The two segments rotated around the center in independent random walks, stepping randomly 4 degrees clockwise or counterclockwise at 60 Hz. Subjects were asked to attend to one or the other while keeping fixation steady at the center of the display. To encourage attention on one or the other segment of the display, subjects were asked to move a joystick in synchrony with the back and forth rotations of one part of the image while ignoring the other. Eye torsion was recorded with the scleral search coil technique, sampled at 500 Hz. All four subjects showed roughly 50% stronger torsion responses to the attended compared to unattended segments. Latency varied from 100 to 150 msec across subjects and was unchanged by attention. These findings suggest that attention can influence eye movement responses that are not typically under voluntary control.

Spectral inputs and ocellar contributions to a pitch-sensitive descending neuron in the honeybee.

PubMed

Hung, Y-S; van Kleef, J P; Stange, G; Ibbotson, M R

2013-02-01

By measuring insect compensatory optomotor reflexes to visual motion, researchers have examined the computational mechanisms of the motion processing system. However, establishing the spectral sensitivity of the neural pathways that underlie this motion behavior has been difficult, and the contribution of the simple eyes (ocelli) has been rarely examined. In this study we investigate the spectral response properties and ocellar inputs of an anatomically identified descending neuron (DNII(2)) in the honeybee optomotor pathway. Using a panoramic stimulus, we show that it responds selectively to optic flow associated with pitch rotations. The neuron is also stimulated with a custom-built light-emitting diode array that presented moving bars that were either all-green (spectrum 500-600 nm, peak 530 nm) or all-short wavelength (spectrum 350-430 nm, peak 380 nm). Although the optomotor response is thought to be dominated by green-sensitive inputs, we show that DNII(2) is equally responsive to, and direction selective to, both green- and short-wavelength stimuli. The color of the background image also influences the spontaneous spiking behavior of the cell: a green background produces significantly higher spontaneous spiking rates. Stimulating the ocelli produces strong modulatory effects on DNII(2), significantly increasing the amplitude of its responses in the preferred motion direction and decreasing the response latency by adding a directional, short-latency response component. Our results suggest that the spectral sensitivity of the optomotor response in honeybees may be more complicated than previously thought and that ocelli play a significant role in shaping the timing of motion signals.

Neuronal mechanisms mediating the variability of somatosensory evoked potentials during sleep oscillations in cats

PubMed Central

Rosanova, Mario; Timofeev, Igor

2005-01-01

The slow oscillation (SO) generated within the corticothalamic system is composed of active and silent states. The studies of response variability during active versus silent network states within thalamocortical system of human and animals provided inconsistent results. To investigate this inconsistency, we used electrophysiological recordings from the main structures of the somatosensory system in anaesthetized cats. Stimulation of the median nerve (MN) elicited cortical responses during all phases of SO. Cortical responses to stimulation of the medial lemniscus (ML) were virtually absent during silent periods. At the ventral-posterior lateral (VPL) level, ML stimuli elicited either EPSPs in isolation or EPSPs crowned by spikes, as a function of membrane potential. Response to MN stimuli elicited compound synaptic responses and spiked at any physiological level of membrane potential. The responses of dorsal column nuclei neurones to MN stimuli were of similar latency, but the latencies of antidromic responses to ML stimuli were variable. Thus, the variable conductance velocity of ascending prethalamic axons was the most likely cause of the barrages of synaptic events in VPL neurones mediating their firing at different level of the membrane potential. We conclude that the preserved ability of the somatosensory system to transmit the peripheral stimuli to the cerebral cortex during all the phases of sleep slow oscillation is based on the functional properties of the medial lemniscus and on the intrinsic properties of the thalamocortical cells. However the reduced firing ability of the cortical neurones during the silent state may contribute to impair sensory processing during sleep. PMID:15528249

Interpersonal Deception Theory: Examining Deception From a Communication Perspective.

DTIC Science & Technology

1998-06-01

4 (type of response) within-subjects factorial de’sign. As expected, deceptive resposes contained more indirect, noniramediate, isnd vague language...framework, with emphasis on the dynamics of interpersonal exchanges. 2. To examine how deceivers’ motivations and locus of benefit ( self or other) influence...replaced by positive signals that foster a favorable image, and performance decrements such as nonfluencies, long response latencies, and self

Study and response time for the visual recognition of 'similarity' and identity

NASA Technical Reports Server (NTRS)

Derks, P. L.; Bauer, T. M.

1974-01-01

Four subjects compared successively presented pairs of line patterns for a match between any lines in the pattern (similarity) and for a match between all lines (identity). The encoding or study times for pattern recognition from immediate memory and the latency in responses to comparison stimuli were examined. Qualitative differences within and between subjects were most evident in study times.

Molecular Basis of Latency in Pathogenic Human Viruses

NASA Astrophysics Data System (ADS)

Garcia-Blanco, Mariano A.; Cullen, Bryan R.

1991-11-01

Several human viruses are able to latently infect specific target cell populations in vivo. Analysis of the replication cycles of herpes simplex virus, Epstein-Barr virus, and human immunodeficiency virus suggests that the latent infections established by these human pathogens primarily result from a lack of host factors critical for the expression of viral early gene products. The subsequent activation of specific cellular transcription factors in response to extracellular stimuli can induce the expression of these viral regulatory proteins and lead to a burst of lytic viral replication. Latency in these eukaryotic viruses therefore contrasts with latency in bacteriophage, which is maintained primarily by the expression of virally encoded repressors of lytic replication.

Cardiovascular responses to railway noise during sleep in young and middle-aged adults.

PubMed

Tassi, Patricia; Saremi, Mahnaz; Schimchowitsch, Sarah; Eschenlauer, Arnaud; Rohmer, Odile; Muzet, Alain

2010-03-01

The aim of this study was to investigate the effects of nocturnal railway noise on cardiovascular reactivity in young (25.8 +/- 2.6 years) and middle-aged (52.2 +/- 2.5 years) adults during sleep. Thirty-eight subjects slept three nights in the laboratory at 1-week interval. They were exposed to 48 randomized pass-bys of Freight, Passenger and Automotive trains either at an 8-h equivalent sound level of 40 dBA (Moderate) and 50 dBA (High) or at a silent Control night. Heart rate response (HRR), heart response amplitude (HRA), heart response latency (HRL) and finger pulse response (FPR), finger pulse amplitude (FPA) and finger pulse latency (FPL) were recorded to measure cardiovascular reactivity after each noise onset and for time-matched pseudo-noises in the control condition. Results show that Freight trains produced the highest cardiac response (increased HRR, HRA and HRL) compared to Passenger and Automotive. But the vascular response was similar whatever the type of train. Juniors exhibited an increased HRR and HRA as compared to seniors, but there was no age difference on vasoconstriction, except a shorter FPL in seniors. Noise level produced dose-dependent effects on all the cardiovascular indices. Sleep stage at noise occurrence was ineffective for cardiac response, but FPA was reduced when noise occurred during REM sleep. In conclusion, our study is in favor of an important impact of nocturnal railway noise on the cardiovascular system of sleeping subjects. In the limit of the samples studied, Freight trains are the most harmful, probably more because of their special length (duration) than because of their speed (rise time).

Simultaneous recording of multifocal VEP responses to short-wavelength and achromatic stimuli

PubMed Central

Wang, Min; Hood, Donald C.

2010-01-01

A paradigm is introduced that allows for simultaneous recording of the pattern-onset multifocal visual evoked potentials (mfVEP) to both short-wavelength (SW) and achromatic (A) stimuli. There were 5 sets of stimulus conditions, each of which is defined by two semi-concurrently presented stimuli, A64/SW (a 64% contrast achromatic stimulus and a short-wavelength stimulus), A64/A8 (64% achromatic/8% achromatic), A0/A8 (0% (gray) achromatic/8% achromatic), A64/A0 and A0/SW. When paired with A64 as part of A64/SW, the SW stimulus yielded mfVEP responses (SWmfVEP) with diminished amplitude in the fovea, consistent with the known sensitivity of the S-cone system. In addition, when A8, which is approximately equal to the L and M cone contribution of the SW stimulus, was recorded alone, the response to A8 was small, but significantly larger than noise. However, when A8 was paired with A64, the response to A8 was reduced to close to noise level, suggesting that the LM cone contribution of the SWmfVEP can be suppressed by A64. When A64 was recorded alone, the response to A64 was about 32% larger than the mfVEP for A64 when paired with the SW. Likewise, the presence of A64 stimulus also reduces the response of SWmfVEP by 35%. Finally, an intense narrow-band yellow background prolonged the latency of SW response for the A0/SW stimulus but not the latency of SW response for the A64/SW stimulus. These results indicate that it is possible to simultaneously record an SWmfVEP with little LM cone contribution along with an achromatic mfVEP. PMID:20499134

Lesions of the thalamic reuniens cause impulsive but not compulsive responses.

PubMed

Prasad, Judy A; Macgregor, Emily M; Chudasama, Yogita

2013-01-01

On account of its strong efferent projections to the hippocampus, recent animal studies have emphasized an important role for the nucleus reuniens (NRe) of the midline thalamus in spatial memory. However, by virtue of its reciprocal connections with the orbital and ventromedial prefrontal cortex, the NRe may also be involved in aspects of executive inhibition. To date, there has been no systematic attempt to examine the role of the NRe in inhibitory mechanisms of response control. Accordingly, we compared rats with neurotoxic lesions of the NRe with sham surgery controls on performance of the 5-choice reaction time task, a test of visuospatial attention and inhibitory control. When tested post-operatively, rats with NRe lesions were unable to actively inhibit premature responses when the intertrial interval was varied. However, the same rats with NRe lesions showed normal inhibition of perseverative responses, and under some conditions were less perseverative than shams. The NRe lesion was also associated with a reduction in omissions and fast reward collection latencies, which persisted 2 months following surgery. The NRe lesion did not affect response accuracy or latency to respond correctly throughout the course of experimental testing. Together, these results signify the important role of the NRe in impulse inhibition, especially when slight changes are made to the temporal demands of the environment, and reveal the potential contribution of the NRe in motivational processes.

Interlimb Coordination in Body-Weight Supported Locomotion: A Pilot Study

PubMed Central

Seiterle, Stefan; Susko, Tyler; Artemiadis, Panagiotis K.; Riener, Robert; Krebs, Hermano Igo

2015-01-01

Locomotion involves complex neural networks responsible for automatic and volitional actions. During locomotion, motor strategies can rapidly compensate for any obstruction or perturbation that could interfere with forward progression. In this pilot study, we examined the contribution of interlimb pathways for evoking muscle activation patterns in the contralateral limb when a unilateral perturbation was applied and in the case where body weight was externally supported. In particular, the latency of neuromuscular responses was measured, while the stimulus to afferent feedback was limited. The pilot experiment was conducted with six healthy young subjects. It employed the MIT-Skywalker (beta-prototype), a novel device intended for gait therapy. Subjects were asked to walk on the split-belt treadmill, while a fast unilateral perturbation was applied mid-stance by unexpectedly lowering one side of the split-treadmill walking surfaces. Subject's weight was externally supported via the body-weight support system consisting of an underneath bicycle seat and the torso was stabilized via a loosely fitted chest harness. Both the weight support and the chest harness limited the afferent feedback. The unilateral perturbations evoked changes in the electromyographic activity of the non-perturbed contralateral leg. The latency of all muscle responses exceeded 100 ms, which precludes the conjecture that spinal cord alone is responsible for the perturbation response. It suggests the role of supraspinal or midbrain level pathways at the inter-leg coordination during gait. PMID:25990210

High-speed duetting - latency times of the female acoustic response within the bush-cricket genera Leptophyes and Andreiniimon (Orthoptera, Phaneropteridae).

PubMed

Heller, Klaus-Gerhard; Korsunovskaya, Olga; Massa, Bruno; Iorgu, Ionuț Ștefan

2018-01-01

To find a mate, male and female bush-crickets of the family Phaneropteridae typically engage in duets. The male sings and the female responds. For mutual recognition, the amplitude pattern of the male song and the species-specific timing of the female response have been shown to be very important. In the seven studied species, belonging to the genera Leptophyes and Andreiniimon , these duets are extremely fast and nearly completely in the ultrasonic range. The females produce very short sounds by fast closing movements of the tegmina. They respond with species-specific delays of 20 to 150 ms after the beginning of the male song. The different latency times are probably not important for species recognition, since in sympatric species they are quite similar.

Auditory thresholds in the American cockroach (Orthoptera: Blattidae): estimates using single-unit and compound-action potential recordings.

PubMed

Decker, T N; Jones, T A; Gold, R E

1989-06-01

Recent commercial suggestions that insect populations can be controlled through the use of ultrasound raises the question of whether or not certain insects have receptors that are sensitive to high-frequency sound. Single neural unit discharges and compound-action potentials were recorded from the ventral nerve cord in the American cockroach, Periplaneta americana L., to constant rise time tone pulses from 100 to 40,000 hertz (Hz). Unit responses and compound-action potentials show that the cockroach is insensitive to sound above approximately 3,000 Hz. Data relating latency of the response to intensity of the stimulus suggest that the cockroach cercal system operates on the principle of energy envelope detection. Decreases in latency likely occur primarily as a result of increases in the rate of membrane depolarization in cercal dendrites.

High-speed duetting – latency times of the female acoustic response within the bush-cricket genera Leptophyes and Andreiniimon (Orthoptera, Phaneropteridae)

PubMed Central

Heller, Klaus-Gerhard; Korsunovskaya, Olga; Massa, Bruno; Iorgu, Ionuț Ștefan

2018-01-01

Abstract To find a mate, male and female bush-crickets of the family Phaneropteridae typically engage in duets. The male sings and the female responds. For mutual recognition, the amplitude pattern of the male song and the species-specific timing of the female response have been shown to be very important. In the seven studied species, belonging to the genera Leptophyes and Andreiniimon, these duets are extremely fast and nearly completely in the ultrasonic range. The females produce very short sounds by fast closing movements of the tegmina. They respond with species-specific delays of 20 to 150 ms after the beginning of the male song. The different latency times are probably not important for species recognition, since in sympatric species they are quite similar. PMID:29692644

The influence of non-nociceptive factors on hot-plate latency in rats.

PubMed

Gunn, Amanda; Bobeck, Erin N; Weber, Ceri; Morgan, Michael M

2011-02-01

The hot plate is a widely used test to assess nociception. The effect of non-nociceptive factors (weight, sex, activity, habituation, and repeated testing) on hot-plate latency was examined. Comparison of body weight and hot-plate latency revealed a small but significant inverse correlation (light rats had longer latencies). Habituating rats to the test room for 1 hour prior to testing did not decrease hot-plate latency except for female rats tested on days 2 to 4. Hot-plate latency decreased with repeated daily testing, but this was not caused by a decrease in locomotor activity or learning to respond. Activity on the hot plate was consistent across all 4 trials, and prior exposure to a room-temperature plate caused a similar decrease in latency as rats tested repeatedly on the hot plate. Despite this decrease in baseline hot-plate latency, there was no difference in morphine antinociceptive potency. The present study shows that weight, habituation to the test room, and repeated testing can alter baseline hot-plate latency, but these effects are small and have relatively little impact on morphine antinociception. This manuscript shows that non-nociceptive factors such as body weight, habituation, and repeated testing can alter hot-plate latency, but these factors do not alter morphine potency. In sum, the hot-plate test is an easy to use and reliable method to assess supraspinally organized nociceptive responses. Copyright © 2011 American Pain Society. Published by Elsevier Inc. All rights reserved.

Effect of Sugar versus Mixed Breakfast on Metabolic and Neurofunctional Responses in Healthy Individuals.

PubMed

Codella, Roberto; Benedini, Stefano; Paini, Stefano; Caumo, Andrea; Adamo, Michela; Terruzzi, Ileana; Ferrulli, Anna; Macrì, Concetta; Andreoni, Luca; Sterlicchio, Michele; Luzi, Livio

2017-01-01

We investigated the effects of glucose and diverse breakfasts on glucose increment and ghrelin suppression and cognitive processing of sensory information assessed by frontal P300 evoked potentials. In a randomized crossover design, 12 healthy individuals (6M/6F; BMI 22.2 ± 0.4 kg/m 2 ; 27 ± 1.3 years, mean ± SEM) underwent 50 g OGTT (A) and 3 breakfasts (B1: milk and cereals; B2: milk, apple, and chocolate cream-filled sponge cake; B3: milk, apple, bread, and hazelnut chocolate cream) to assess plasma glucose-, insulin-, and ghrelin excursions. An electroencephalography was performed before and 100 min after consumption of each load to measure the latency of frontal P300 evoked potentials as index of cognitive performance. Breakfasts B1 and B2 exhibited significantly lower glycemic and insulinemic responses as compared to A. Breakfast B3 exhibited significantly lower glycemic, but not insulinemic response, as compared to A. Final plasma ghrelin inhibition was more pronounced, albeit not significantly, in all breakfasts with respect to A. P300 latency tended to decrease following each of the three breakfasts, but B3 was the only breakfast capable to elicit a statistically significant reduction in P300 latency with respect to A ( p < 0.01), suggesting ameliorated cognitive performance. Such amelioration was correlated with the 2-hour final inhibition of plasma ghrelin concentration ( r = 0.61, p = 0.01).

Abnormal reflex activation of hamstring muscles in dogs with cranial cruciate ligament rupture.

PubMed

Hayes, Graham M; Granger, Nicolas; Langley-Hobbs, Sorrel J; Jeffery, Nick D

2013-06-01

The mechanisms underlying cranial cruciate ligament rupture (CCLR) in dogs are poorly understood. In this study hamstring muscle reflexes in response to cranial tibial translation were analysed to determine whether these active stabilisers of the stifle joint are differently activated in dogs with CCLR compared to control dogs. In a prospective clinical study reflex muscle activity from the lateral and medial hamstring muscles (biceps femoris and semimembranosus) was recorded using surface electrodes in control dogs (n=21) and dogs with CCLR (n=22). These electromyographic recordings were analysed using an algorithm previously validated in humans. The hamstring reflex was reliably and reproducibly recorded in normal dogs. Both a short latency response (SLR, 17.6±2.1ms) and a medium latency response (MLR, 37.7±2.7ms) could be identified. In dogs with unilateral CCLR, the SLR and MLR were not significantly different between the affected and the unaffected limbs, but the MLR latency of both affected and unaffected limbs in CCLR dogs were significantly prolonged compared to controls. In conclusion, the hamstring reflex can be recorded in dogs and the MLR is prolonged in dogs with CCLR. Since both affected and unaffected limbs exhibit prolonged MLR, it is possible that abnormal hamstring reflex activation is a mechanism by which progressive CCL damage may occur. The methodology allows for further investigation of the relationship between neuromuscular imbalance and CCLR or limitations in functional recovery following surgical intervention. Copyright © 2012 Elsevier Ltd. All rights reserved.

Pupillary behavior in relation to wavelength and age

PubMed Central

Lobato-Rincón, Luis-Lucio; Cabanillas-Campos, Maria del Carmen; Bonnin-Arias, Cristina; Chamorro-Gutiérrez, Eva; Murciano-Cespedosa, Antonio; Sánchez-Ramos Roda, Celia

2014-01-01

Pupil light reflex can be used as a non-invasive ocular predictor of cephalic autonomic nervous system integrity. Spectral sensitivity of the pupil's response to light has, for some time, been an interesting issue. It has generally, however, only been investigated with the use of white light and studies with monochromatic wavelengths are scarce. This study investigates the effects of wavelength and age within three parameters of the pupil light reflex (amplitude of response, latency, and velocity of constriction) in a large sample of younger and older adults (N = 97), in mesopic conditions. Subjects were exposed to a single light stimulus at four different wavelengths: white (5600°K), blue (450 nm), green (510 nm), and red (600 nm). Data was analyzed appropriately, and, when applicable, using the General Linear Model (GLM), Randomized Complete Block Design (RCBD), Student's t-test and/or ANCOVA. Across all subjects, pupillary response to light had the greatest amplitude and shortest latency in white and green light conditions. In regards to age, older subjects (46–78 years) showed an increased latency in white light and decreased velocity of constriction in green light compared to younger subjects (18–45 years old). This study provides data patterns on parameters of wavelength-dependent pupil reflexes to light in adults and it contributes to the large body of pupillometric research. It is hoped that this study will add to the overall evaluation of cephalic autonomic nervous system integrity. PMID:24795595

Effect of Sugar versus Mixed Breakfast on Metabolic and Neurofunctional Responses in Healthy Individuals

PubMed Central

Paini, Stefano; Caumo, Andrea; Macrì, Concetta; Andreoni, Luca; Sterlicchio, Michele

2017-01-01

We investigated the effects of glucose and diverse breakfasts on glucose increment and ghrelin suppression and cognitive processing of sensory information assessed by frontal P300 evoked potentials. In a randomized crossover design, 12 healthy individuals (6M/6F; BMI 22.2 ± 0.4 kg/m2; 27 ± 1.3 years, mean ± SEM) underwent 50 g OGTT (A) and 3 breakfasts (B1: milk and cereals; B2: milk, apple, and chocolate cream-filled sponge cake; B3: milk, apple, bread, and hazelnut chocolate cream) to assess plasma glucose-, insulin-, and ghrelin excursions. An electroencephalography was performed before and 100 min after consumption of each load to measure the latency of frontal P300 evoked potentials as index of cognitive performance. Breakfasts B1 and B2 exhibited significantly lower glycemic and insulinemic responses as compared to A. Breakfast B3 exhibited significantly lower glycemic, but not insulinemic response, as compared to A. Final plasma ghrelin inhibition was more pronounced, albeit not significantly, in all breakfasts with respect to A. P300 latency tended to decrease following each of the three breakfasts, but B3 was the only breakfast capable to elicit a statistically significant reduction in P300 latency with respect to A (p < 0.01), suggesting ameliorated cognitive performance. Such amelioration was correlated with the 2-hour final inhibition of plasma ghrelin concentration (r = 0.61, p = 0.01). PMID:28706955

Reliability and discriminative validity of sudden ankle inversion measurements in patients with chronic ankle instability.

PubMed

Eechaute, Christophe; Vaes, Peter; Duquet, William; Van Gheluwe, Bart

2009-07-01

Studies investigating peroneal muscle reaction times in chronically unstable ankle joints present conflicting results. The degree of reliability and accuracy of these measurements is unknown in patients with chronic ankle instability (CAI). 40 patients with CAI and 30 healthy subjects were tested using a sudden ankle inversion of 50 degrees while standing on a trapdoor device. Sudden ankle inversion measurements were registered using electromyography, accelerometry and electrogoniometry. For reliability testing, intra-class coefficients (ICCs; model 3,1) and standard errors of measurements of the latency time, motor response time and electromechanical delay of the peroneus longus muscle, the time and angular position of onset of decelerations, the mean and maximum inversion speed and the total inversion time were calculated in 15 patients with CAI. To assess between-group differences, t-tests for independent samples (p<.05) were used. ICCs ranged from .20 (angular position of onset of the second deceleration) to .98 (electromechanical delay of the peroneus longus muscle). Significant between-group differences were observed in only 2 of the 12 variables (for the electromechanical delay of the peroneus longus muscle, p=.001; time of onset of the second deceleration, p=.040). The latency time and motor response time of the peroneus longus muscle, the total inversion time and the mean inversion speed demonstrate acceptable reliability in healthy subjects and patients. The latency time and motor response time of the peroneus longus muscle are not delayed in patients with CAI. Ankle inversion measurements are not discriminative for CAI.

Potential effects of reward and loss avoidance in overweight adolescents.

PubMed

Reyes, Sussanne; Peirano, Patricio; Luna, Beatriz; Lozoff, Betsy; Algarín, Cecilia

2015-08-01

Reward system and inhibitory control are brain functions that exert an influence on eating behavior regulation. We studied the differences in inhibitory control and sensitivity to reward and loss avoidance between overweight/obese and normal-weight adolescents. We assessed 51 overweight/obese and 52 normal-weight 15-y-old Chilean adolescents. The groups were similar regarding sex and intelligence quotient. Using Antisaccade and Incentive tasks, we evaluated inhibitory control and the effect of incentive trials (neutral, loss avoidance, and reward) on generating correct and incorrect responses (latency and error rate). Compared to normal-weight group participants, overweight/obese adolescents showed shorter latency for incorrect antisaccade responses (186.0 (95% CI: 176.8-195.2) vs. 201.3 ms (95% CI: 191.2-211.5), P < 0.05) and better performance reflected by lower error rate in incentive trials (43.6 (95% CI: 37.8-49.4) vs. 53.4% (95% CI: 46.8-60.0), P < 0.05). Overweight/obese adolescents were more accurate on loss avoidance (40.9 (95% CI: 33.5-47.7) vs. 49.8% (95% CI: 43.0-55.1), P < 0.05) and reward (41.0 (95% CI: 34.5-47.5) vs. 49.8% (95% CI: 43.0-55.1), P < 0.05) compared to neutral trials. Overweight/obese adolescents showed shorter latency for incorrect responses and greater accuracy in reward and loss avoidance trials. These findings could suggest that an imbalance of inhibition and reward systems influence their eating behavior.

Laterodorsal Nucleus of the Thalamus: A Processor of Somatosensory Inputs

PubMed Central

BEZDUDNAYA, TATIANA; KELLER, ASAF

2009-01-01

The laterodorsal (LD) nucleus of the thalamus has been considered a “higher order” nucleus that provides inputs to limbic cortical areas. Although its functions are largely unknown, it is often considered to be involved in spatial learning and memory. Here we provide evidence that LD is part of a hitherto unknown pathway for processing somatosensory information. Juxtacellular and extracellular recordings from LD neurons reveal that they respond to vibrissa stimulation with short latency (median = 7 ms) and large magnitude responses (median = 1.2 spikes/stimulus). Most neurons (62%) had large receptive fields, responding to six and more individual vibrissae. Electrical stimulation of the trigeminal nucleus interpolaris (SpVi) evoked short latency responses (median = 3.8 ms) in vibrissa-responsive LD neurons. Labeling produced by anterograde and retrograde neuroanatomical tracers confirmed that LD neurons receive direct inputs from SpVi. Electrophysiological and neuroanatomical analyses revealed also that LD projects upon the cingulate and retrosplenial cortex, but has only sparse projections to the barrel cortex. These findings suggest that LD is part of a novel processing stream involved in spatial orientation and learning related to somatosensory cues. PMID:18273888

Novel measures of response performance and inhibition in children with ADHD.

PubMed

Morein-Zamir, Sharon; Hommersen, Paul; Johnston, Charlotte; Kingstone, Alan

2008-11-01

Fifteen children with ADHD aged 8 to 12 years and age and gender matched controls performed two different stopping tasks to examine response performance and inhibition and their respective moment-to-moment variability. One task was the well-established stop-signal task, while the other was a novel tracking task where the children tracked a spaceship on the screen until an alarm indicated they should stop. Although performance was discrete in the stop signal task and continuous in the tracking task, in both tasks latencies to the stop signal were significantly slowed in children with ADHD. Go performance and variability did not significantly differ between ADHD and control children in either task. Importantly, stopping latency in the novel spaceship tracking task also was more variable in children with ADHD. As stopping variability cannot be measured using the standard stop signal task, the new task offers compelling support for the heretofore untested prediction that stopping is both slowed and more variable in children with ADHD. The results support a response inhibition impairment in ADHD, whilst limiting the extent of an intra-trial variability deficit.

Quick concurrent responses to global and local cognitive information underlie intuitive understanding in board-game experts

PubMed Central

Nakatani, Hironori; Yamaguchi, Yoko

2014-01-01

Experts have the superior cognitive capability of quickly understanding complex information in their domain; however, little is known about the neural processes underlying this ability. Here, using a board game named shogi (Japanese chess), we investigated the brain activity in expert players that was involved in their quick understanding of board-game patterns. The frontal area responded only to meaningful game positions, whereas the temporal area responded to both game and random positions with the same latency (200 ms). Subsequent to these quick responses, the temporal and parietal areas responded only to game positions, with a latency of 700 ms. During the responses, enhanced phase synchronization between these areas was observed. Thus, experts first responded to global cognitive information that was specific to game positions and to local cognitive information that was common to game and random positions concurrently. These types of information were integrated via neural synchronization at the posterior areas. As these properties were specific to experts, much of the experts' advantage in understanding game positions occurred within 1 s of perception. PMID:25081320

Axonal Conduction Delays, Brain State, and Corticogeniculate Communication

PubMed Central

2017-01-01

Thalamocortical conduction times are short, but layer 6 corticothalamic axons display an enormous range of conduction times, some exceeding 40–50 ms. Here, we investigate (1) how axonal conduction times of corticogeniculate (CG) neurons are related to the visual information conveyed to the thalamus, and (2) how alert versus nonalert awake brain states affect visual processing across the spectrum of CG conduction times. In awake female Dutch-Belted rabbits, we found 58% of CG neurons to be visually responsive, and 42% to be unresponsive. All responsive CG neurons had simple, orientation-selective receptive fields, and generated sustained responses to stationary stimuli. CG axonal conduction times were strongly related to modulated firing rates (F1 values) generated by drifting grating stimuli, and their associated interspike interval distributions, suggesting a continuum of visual responsiveness spanning the spectrum of axonal conduction times. CG conduction times were also significantly related to visual response latency, contrast sensitivity (C-50 values), directional selectivity, and optimal stimulus velocity. Increasing alertness did not cause visually unresponsive CG neurons to become responsive and did not change the response linearity (F1/F0 ratios) of visually responsive CG neurons. However, for visually responsive CG neurons, increased alertness nearly doubled the modulated response amplitude to optimal visual stimulation (F1 values), significantly shortened response latency, and dramatically increased response reliability. These effects of alertness were uniform across the broad spectrum of CG axonal conduction times. SIGNIFICANCE STATEMENT Corticothalamic neurons of layer 6 send a dense feedback projection to thalamic nuclei that provide input to sensory neocortex. While sensory information reaches the cortex after brief thalamocortical axonal delays, corticothalamic axons can exhibit conduction delays of <2 ms to 40–50 ms. Here, in the corticogeniculate visual system of awake rabbits, we investigate the functional significance of this axonal diversity, and the effects of shifting alert/nonalert brain states on corticogeniculate processing. We show that axonal conduction times are strongly related to multiple visual response properties, suggesting a continuum of visual responsiveness spanning the spectrum of corticogeniculate axonal conduction times. We also show that transitions between awake brain states powerfully affect corticogeniculate processing, in some ways more strongly than in layer 4. PMID:28559382

Contribution of different classes of glutamate receptors in the corticostriatal polysynaptic responses from striatal direct and indirect projection neurons

PubMed Central

2013-01-01

Background Previous work showed differences in the polysynaptic activation of GABAergic synapses during corticostriatal suprathreshold responses in direct and indirect striatal projection neurons (dSPNs and iSPNs). Here, we now show differences and similarities in the polysynaptic activation of cortical glutamatergic synapses on the same responses. Corticostriatal contacts have been extensively studied. However, several questions remain unanswered, e.g.: what are the differences and similarities in the responses to glutamate in dSPNs and iSPNs? Does glutamatergic synaptic activation exhibits a distribution of latencies over time in vitro? That would be a strong suggestion of polysynaptic cortical convergence. What is the role of kainate receptors in corticostriatal transmission? Current-clamp recordings were used to answer these questions. One hypothesis was: if prolonged synaptic activation distributed along time was present, then it would be mainly generated from the cortex, and not from the striatum. Results By isolating responses from AMPA-receptors out of the complex suprathreshold response of SPNs, it is shown that a single cortical stimulus induces early and late synaptic activation lasting hundreds of milliseconds. Prolonged responses depended on cortical stimulation because they could not be elicited using intrastriatal stimulation, even if GABAergic transmission was blocked. Thus, the results are not explained by differences in evoked inhibition. Moreover, inhibitory participation was larger after cortical than after intrastriatal stimulation. A strong activation of interneurons was obtained from the cortex, demonstrating that polysynaptic activation includes the striatum. Prolonged kainate (KA) receptor responses were also elicited from the cortex. Responses of dSPNs and iSPNs did not depend on the cortical area stimulated. In contrast to AMPA-receptors, responses from NMDA- and KA-receptors do not exhibit early and late responses, but generate slow responses that contribute to plateau depolarizations. Conclusions As it has been established in previous physiological studies in vivo, synaptic invasion over different latencies, spanning hundreds of milliseconds after a single stimulus strongly indicates convergent polysynaptic activation. Interconnected cortical neurons converging on the same SPNs may explain prolonged corticostriatal responses. Glutamate receptors participation in these responses is described as well as differences and similarities between dSPNs and iSPNs. PMID:23782743

Interaction of cellular and network mechanisms for efficient pheromone coding in moths.

PubMed

Belmabrouk, Hana; Nowotny, Thomas; Rospars, Jean-Pierre; Martinez, Dominique

2011-12-06

Sensory systems, both in the living and in machines, have to be optimized with respect to their environmental conditions. The pheromone subsystem of the olfactory system of moths is a particularly well-defined example in which rapid variations of odor content in turbulent plumes require fast, concentration-invariant neural representations. It is not clear how cellular and network mechanisms in the moth antennal lobe contribute to coding efficiency. Using computational modeling, we show that intrinsic potassium currents (I(A) and I(SK)) in projection neurons may combine with extrinsic inhibition from local interneurons to implement a dual latency code for both pheromone identity and intensity. The mean latency reflects stimulus intensity, whereas latency differences carry concentration-invariant information about stimulus identity. In accordance with physiological results, the projection neurons exhibit a multiphasic response of inhibition-excitation-inhibition. Together with synaptic inhibition, intrinsic currents I(A) and I(SK) account for the first and second inhibitory phases and contribute to a rapid encoding of pheromone information. The first inhibition plays the role of a reset to limit variability in the time to first spike. The second inhibition prevents responses of excessive duration to allow tracking of intermittent stimuli.

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

PubMed

Cobb, Kensi M; Stuart, Andrew

2014-11-01

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

Early adverse experiences and the neurobiology of facial emotion processing.

PubMed

Moulson, Margaret C; Fox, Nathan A; Zeanah, Charles H; Nelson, Charles A

2009-01-01

To examine the neurobiological consequences of early institutionalization, the authors recorded event-related potentials (ERPs) from 3 groups of Romanian children--currently institutionalized, previously institutionalized but randomly assigned to foster care, and family-reared children--in response to pictures of happy, angry, fearful, and sad facial expressions of emotion. At 3 assessments (baseline, 30 months, and 42 months), institutionalized children showed markedly smaller amplitudes and longer latencies for the occipital components P1, N170, and P400 compared to family-reared children. By 42 months, ERP amplitudes and latencies of children placed in foster care were intermediate between the institutionalized and family-reared children, suggesting that foster care may be partially effective in ameliorating adverse neural changes caused by institutionalization. The age at which children were placed into foster care was unrelated to their ERP outcomes at 42 months. Facial emotion processing was similar in all 3 groups of children; specifically, fearful faces elicited larger amplitude and longer latency responses than happy faces for the frontocentral components P250 and Nc. These results have important implications for understanding of the role that experience plays in shaping the developing brain.

Auditory brainstem evoked responses and temperature monitoring during pediatric cardiopulmonary bypass.

PubMed

Rodriguez, R A; Edmonds, H L; Auden, S M; Austin, E H

1999-09-01

To examine the effects of temperature on auditory brainstem responses (ABRs) in infants during hypothermic cardiopulmonary bypass for total circulatory arrest (TCA). The relationship between ABRs (as a surrogate measure of core-brain temperature) and body temperature as measured at several temperature monitoring sites was determined. In a prospective, observational study, ABRs were recorded non-invasively at normothermia and at every 1 or 2 degrees C change in ear-canal temperature during cooling and rewarming in 15 infants (ages: 2 days to 14 months) that required TCA. The ABR latencies and amplitudes and the lowest temperatures at which an ABR was identified (the threshold) were measured during both cooling and rewarming. Temperatures from four standard temperature monitoring sites were simultaneously recorded. The latencies of ABRs increased and amplitudes decreased with cooling (P < 0.01), but rewarming reversed these effects. The ABR threshold temperature as related to each monitoring site (ear-canal, nasopharynx, esophagus and bladder) was respectively determined as 23 +/- 2.2 degrees C, 20.8 +/- 1.7 degrees C, 14.6 +/- 3.4 degrees C, and 21.5 +/- 3.8 degrees C during cooling and 21.8 +/- 1.6 degrees C, 22.4 +/- 2.0 degrees C, 27.6 +/- 3.6 degrees C, and 23.0 +/- 2.4 degrees C during rewarming. The rewarming latencies were shorter and Q10 latencies smaller than the corresponding cooling values (P < 0.01). Esophageal and bladder sites were more susceptible to temperature variations as compared with the ear-canal and nasopharynx. No temperature site reliably predicted an electrophysiological threshold. A faster latency recovery during rewarming suggests that body temperature monitoring underestimates the effects of rewarming in the core-brain. ABRs may be helpful to monitor the effects of cooling and rewarming on the core-brain during pediatric cardiopulmonary bypass.

Cortical Auditory Evoked Potentials with Simple (Tone Burst) and Complex (Speech) Stimuli in Children with Cochlear Implant

PubMed Central

Martins, Kelly Vasconcelos Chaves; Gil, Daniela

2017-01-01

Introduction  The registry of the component P1 of the cortical auditory evoked potential has been widely used to analyze the behavior of auditory pathways in response to cochlear implant stimulation. Objective  To determine the influence of aural rehabilitation in the parameters of latency and amplitude of the P1 cortical auditory evoked potential component elicited by simple auditory stimuli (tone burst) and complex stimuli (speech) in children with cochlear implants. Method  The study included six individuals of both genders aged 5 to 10 years old who have been cochlear implant users for at least 12 months, and who attended auditory rehabilitation with an aural rehabilitation therapy approach. Participants were submitted to research of the cortical auditory evoked potential at the beginning of the study and after 3 months of aural rehabilitation. To elicit the responses, simple stimuli (tone burst) and complex stimuli (speech) were used and presented in free field at 70 dB HL. The results were statistically analyzed, and both evaluations were compared. Results  There was no significant difference between the type of eliciting stimulus of the cortical auditory evoked potential for the latency and the amplitude of P1. There was a statistically significant difference in the P1 latency between the evaluations for both stimuli, with reduction of the latency in the second evaluation after 3 months of auditory rehabilitation. There was no statistically significant difference regarding the amplitude of P1 under the two types of stimuli or in the two evaluations. Conclusion  A decrease in latency of the P1 component elicited by both simple and complex stimuli was observed within a three-month interval in children with cochlear implant undergoing aural rehabilitation. PMID:29018498

Prolongation of latencies for passive avoidance responses in rats treated with aniracetam or piracetam.

PubMed

Yamada, K; Inoue, T; Tanaka, M; Furukawa, T

1985-04-01

Effects of aniracetam (1-anysoyl-2-pyrrolodone) and piracetam (1-acetamido-2-pyrrolidone) on passive avoidance behavior were studied in 2 and 18 months old rats using a step-down passive avoidance task. Repeated administration of aniracetam (30 and 50 mg/kg, IP X 5 days) or piracetam (100 mg/kg, IP X 5 days) significantly prolonged step-down latencies for a passive avoidance task in 2 months old rats. Administration of aniracetam (50 mg/kg, IP) or piracetam (100 mg/kg, IP), however, did not affect locomotor activity. This prolongation of latencies was also seen with oral administration of aniracetam (50 mg/kg X 5 days). Similar prolongation of latencies also occurred in 18 months old rat treated with aniracetam (50 mg/kg, IP X 5 days). The results imply that aniracetam may improve learning and/or memory in 2 and 18 months old rats.

Can implicit appraisal concepts produce emotion-specific effects? A focus on unfairness and anger.

PubMed

Tong, Eddie M W; Tan, Deborah H; Tan, Yan Lin

2013-06-01

This research examined whether the non-conscious activation of an implicit appraisal concept could affect responses associated with the corresponding emotion as predicted by appraisal theories. Explicit and implicit emotional responses were examined. We focused on implicit unfairness and its effect on anger. The results show that subliminal activation of implicit unfairness affected implicit anger responses (anger facial expression and latency responses to anger words) but not explicit anger feelings (i.e., reported anger). The non-conscious effect of implicit unfairness was specific to anger, as no effect on sadness, fear, and guilt was found. Copyright © 2013 Elsevier Inc. All rights reserved.

Feedback Effects in Computer-Based Skill Learning

DTIC Science & Technology

1989-09-12

SUPPLEMENTARY NOTATION 17 COSATI CODES 18 SUBJECT TERMS (Continue on reverse if necessary and identify by block number) r FIELD GROUP SUB-GROUP I...rather than tangible feedback ( Barringer & Gholson, 1979) and when they receive punishment (either alone or witih reward) rather than reward alone...34graphed" response latencies across the four conditions ( r = .58), indicating that subjects were sensitive to block-by-block trends in their response

Visual field asymmetries in visual evoked responses

PubMed Central

Hagler, Donald J.

2014-01-01

Behavioral responses to visual stimuli exhibit visual field asymmetries, but cortical folding and the close proximity of visual cortical areas make electrophysiological comparisons between different stimulus locations problematic. Retinotopy-constrained source estimation (RCSE) uses distributed dipole models simultaneously constrained by multiple stimulus locations to provide separation between individual visual areas that is not possible with conventional source estimation methods. Magnetoencephalography and RCSE were used to estimate time courses of activity in V1, V2, V3, and V3A. Responses to left and right hemifield stimuli were not significantly different. Peak latencies for peripheral stimuli were significantly shorter than those for perifoveal stimuli in V1, V2, and V3A, likely related to the greater proportion of magnocellular input to V1 in the periphery. Consistent with previous results, sensor magnitudes for lower field stimuli were about twice as large as for upper field, which is only partially explained by the proximity to sensors for lower field cortical sources in V1, V2, and V3. V3A exhibited both latency and amplitude differences for upper and lower field responses. There were no differences for V3, consistent with previous suggestions that dorsal and ventral V3 are two halves of a single visual area, rather than distinct areas V3 and VP. PMID:25527151

A comparison of vestibular evoked myogenic potential (VEMP) between definite Meniere's disease patients and normal healthy adults.

PubMed

Jariengprasert, Chanchai; Tiensuwan, Montip; Euasirirattanapaisan, Khongpol

2013-12-01

To compare the results of VEMP between unilateral definite Meniere's disease patients and normal healthy adults. Thirty-two patients with unilateral definite Meniere's disease patients and 32 age-matched normal healthy adults (control) underwent VEMP tests with short tone burst of 500 Hz at 90 dBnHL. Student-t test was used for comparison of means of all parameters between two groups. Absent VEMP response was found in 14 MD patients and abnormal asymmetry ratio (AR) was found in five MD patients. Normal responses were found in all subjects of the control group. The mean P1 and N1 latencies, VEMP amplitude between unilateral MD, and control were not significantly different between two groups. However the difference between the mean AR of both groups showed statistically significant (p-value < 0.05). The upper limit of normal AR was calculated to be of 35.15%. The absence of VEMP response and AR of VEMP were more dominant than other parameters such as P1 and N1 latencies or VEMP amplitude in the detection of saccular dysfunction in MD. The results suggested that AR should be used as a tool in interpretation of VEMP response for the diagnostic batteries in MD. The upper limit of normal AR of < or = 35% should be recommended.

Target representation of naturalistic echolocation sequences in single unit responses from the inferior colliculus of big brown bats

NASA Astrophysics Data System (ADS)

Sanderson, Mark I.; Simmons, James A.

2005-11-01

Echolocating big brown bats (Eptesicus fuscus) emit trains of frequency-modulated (FM) biosonar signals whose duration, repetition rate, and sweep structure change systematically during interception of prey. When stimulated with a 2.5-s sequence of 54 FM pulse-echo pairs that mimic sounds received during search, approach, and terminal stages of pursuit, single neurons (N=116) in the bat's inferior colliculus (IC) register the occurrence of a pulse or echo with an average of <1 spike/sound. Individual IC neurons typically respond to only a segment of the search or approach stage of pursuit, with fewer neurons persisting to respond in the terminal stage. Composite peristimulus-time-histogram plots of responses assembled across the whole recorded population of IC neurons depict the delay of echoes and, hence, the existence and distance of the simulated biosonar target, entirely as on-response latencies distributed across time. Correlated changes in pulse duration, repetition rate, and pulse or echo amplitude do modulate the strength of responses (probability of the single spike actually occurring for each sound), but registration of the target itself remains confined exclusively to the latencies of single spikes across cells. Modeling of echo processing in FM biosonar should emphasize spike-time algorithms to explain the content of biosonar images.

Auditory brainstem responses predict auditory nerve fiber thresholds and frequency selectivity in hearing impaired chinchillas

PubMed Central

Henry, Kenneth S.; Kale, Sushrut; Scheidt, Ryan E.; Heinz, Michael G.

2011-01-01

Non-invasive auditory brainstem responses (ABRs) are commonly used to assess cochlear pathology in both clinical and research environments. In the current study, we evaluated the relationship between ABR characteristics and more direct measures of cochlear function. We recorded ABRs and auditory nerve (AN) single-unit responses in seven chinchillas with noise induced hearing loss. ABRs were recorded for 1–8 kHz tone burst stimuli both before and several weeks after four hours of exposure to a 115 dB SPL, 50 Hz band of noise with a center frequency of 2 kHz. Shifts in ABR characteristics (threshold, wave I amplitude, and wave I latency) following hearing loss were compared to AN-fiber tuning curve properties (threshold and frequency selectivity) in the same animals. As expected, noise exposure generally resulted in an increase in ABR threshold and decrease in wave I amplitude at equal SPL. Wave I amplitude at equal sensation level (SL), however, was similar before and after noise exposure. In addition, noise exposure resulted in decreases in ABR wave I latency at equal SL and, to a lesser extent, at equal SPL. The shifts in ABR characteristics were significantly related to AN-fiber tuning curve properties in the same animal at the same frequency. Larger shifts in ABR thresholds and ABR wave I amplitude at equal SPL were associated with greater AN threshold elevation. Larger reductions in ABR wave I latency at equal SL, on the other hand, were associated with greater loss of AN frequency selectivity. This result is consistent with linear systems theory, which predicts shorter time delays for broader peripheral frequency tuning. Taken together with other studies, our results affirm that ABR thresholds and wave I amplitude provide useful estimates of cochlear sensitivity. Furthermore, comparisons of ABR wave I latency to normative data at the same SL may prove useful for detecting and characterizing loss of cochlear frequency selectivity. PMID:21699970

Relationship between early and late stages of information processing: an event-related potential study

PubMed Central

Portella, Claudio; Machado, Sergio; Arias-Carrión, Oscar; Sack, Alexander T.; Silva, Julio Guilherme; Orsini, Marco; Leite, Marco Antonio Araujo; Silva, Adriana Cardoso; Nardi, Antonio E.; Cagy, Mauricio; Piedade, Roberto; Ribeiro, Pedro

2012-01-01

The brain is capable of elaborating and executing different stages of information processing. However, exactly how these stages are processed in the brain remains largely unknown. This study aimed to analyze the possible correlation between early and late stages of information processing by assessing the latency to, and amplitude of, early and late event-related potential (ERP) components, including P200, N200, premotor potential (PMP) and P300, in healthy participants in the context of a visual oddball paradigm. We found a moderate positive correlation among the latency of P200 (electrode O2), N200 (electrode O2), PMP (electrode C3), P300 (electrode PZ) and the reaction time (RT). In addition, moderate negative correlation between the amplitude of P200 and the latencies of N200 (electrode O2), PMP (electrode C3), P300 (electrode PZ) was found. Therefore, we propose that if the secondary processing of visual input (P200 latency) occurs faster, the following will also happen sooner: discrimination and classification process of this input (N200 latency), motor response processing (PMP latency), reorganization of attention and working memory update (P300 latency), and RT. N200, PMP, and P300 latencies are also anticipated when higher activation level of occipital areas involved in the secondary processing of visual input rise (P200 amplitude). PMID:23355929

Achilles Tendon Reflex (ATR) in response to short exposures of microgravity and hypergravity

NASA Technical Reports Server (NTRS)

Fujii, M.; Jaweed, M.

1992-01-01

Previous studies indicate that latency and amplitude of the Achilles tendon reflex (ATR) are reduced after exposure to microgravity for 28 days. The objective of this study was to quantitatively measure the latency of ATR during brief (20 sec) exposure to microgravity in KC-135 parabolic flights. Methods: The ATR was elicited in ten men during parabolic flight with the ankle held neutrally, planarflexed, and dorsiflexed. During flight, the ATR was elicited during the zero G and 1.8 G phases. Postflight testing was performed flying back to the airfield. Latencies to onset of the ATR were calculated and analyses of variance were performed to determine the effect of gravity and ankle position on latency. Result: The mean latencies for zero-G, 1.8-G and postflight with the ankle in the neutral position were 32.7 plus or minus 0.5 ms, and 33.1 plus or minus 0.7 ms respectively, which were not significantly different. There was a trend toward prolongation of latencies postflight. The mean latency for those who were motion sick was 32.1 plus or minus 0.1 ms compared to 34.0 plus or minus 0.3 ms for those who were not sick. Conclusions: These studies indicate that neither the level of gravity nor ankle position significantly affected the latency of the ATR.

The construction of categorization judgments: using subjective confidence and response latency to test a distributed model.

PubMed

Koriat, Asher; Sorka, Hila

2015-01-01

The classification of objects to natural categories exhibits cross-person consensus and within-person consistency, but also some degree of between-person variability and within-person instability. What is more, the variability in categorization is also not entirely random but discloses systematic patterns. In this study, we applied the Self-Consistency Model (SCM, Koriat, 2012) to category membership decisions, examining the possibility that confidence judgments and decision latency track the stable and variable components of categorization responses. The model assumes that category membership decisions are constructed on the fly depending on a small set of clues that are sampled from a commonly shared population of pertinent clues. The decision and confidence are based on the balance of evidence in favor of a positive or a negative response. The results confirmed several predictions derived from SCM. For each participant, consensual responses to items were more confident than non-consensual responses, and for each item, participants who made the consensual response tended to be more confident than those who made the nonconsensual response. The difference in confidence between consensual and nonconsensual responses increased with the proportion of participants who made the majority response for the item. A similar pattern was observed for response speed. The pattern of results obtained for cross-person consensus was replicated by the results for response consistency when the responses were classified in terms of within-person agreement across repeated presentations. These results accord with the sampling assumption of SCM, that confidence and response speed should be higher when the decision is consistent with what follows from the entire population of clues than when it deviates from it. Results also suggested that the context for classification can bias the sample of clues underlying the decision, and that confidence judgments mirror the effects of context on categorization decisions. The model and results offer a principled account of the stable and variable contributions to categorization behavior within a decision-making framework. Copyright © 2014 Elsevier B.V. All rights reserved.

Cerebral asymmetry for mental rotation: effects of response hand, handedness and gender.

PubMed

Johnson, Blake W; McKenzie, Kirsten J; Hamm, Jeff P

2002-10-28

We assessed lateralization of brain function during mental rotation, measuring the scalp distribution of a 400-600 ms latency event-related potential (ERP) with 128 recording electrodes. Twenty-four subjects, consisting of equal numbers of dextral and sinistral males and females, performed a mental rotation task under two response conditions (dominant non-dominant hand). For males, ERPs showed a right parietal bias regardless of response hand. For females, the parietal ERPs were slightly left-lateralized when making dominant hand responses, but strongly right-lateralized when making non-dominant hand responses. These results support the notion that visuo-spatial processing is more bilaterally organized in females. However, left hemisphere resources may be allocated to response preparation when using the non-dominant hand, forcing visuo-spatial processing to the right hemisphere.

Processing of harmonics in the lateral belt of macaque auditory cortex.

PubMed

Kikuchi, Yukiko; Horwitz, Barry; Mishkin, Mortimer; Rauschecker, Josef P

2014-01-01

Many speech sounds and animal vocalizations contain components, referred to as complex tones, that consist of a fundamental frequency (F0) and higher harmonics. In this study we examined single-unit activity recorded in the core (A1) and lateral belt (LB) areas of auditory cortex in two rhesus monkeys as they listened to pure tones and pitch-shifted conspecific vocalizations ("coos"). The latter consisted of complex-tone segments in which F0 was matched to a corresponding pure-tone stimulus. In both animals, neuronal latencies to pure-tone stimuli at the best frequency (BF) were ~10 to 15 ms longer in LB than in A1. This might be expected, since LB is considered to be at a hierarchically higher level than A1. On the other hand, the latency of LB responses to coos was ~10 to 20 ms shorter than to the corresponding pure-tone BF, suggesting facilitation in LB by the harmonics. This latency reduction by coos was not observed in A1, resulting in similar coo latencies in A1 and LB. Multi-peaked neurons were present in both A1 and LB; however, harmonically-related peaks were observed in LB for both early and late response components, whereas in A1 they were observed only for late components. Our results suggest that harmonic features, such as relationships between specific frequency intervals of communication calls, are processed at relatively early stages of the auditory cortical pathway, but preferentially in LB.

Processing of harmonics in the lateral belt of macaque auditory cortex

PubMed Central

Kikuchi, Yukiko; Horwitz, Barry; Mishkin, Mortimer; Rauschecker, Josef P.

2014-01-01

Many speech sounds and animal vocalizations contain components, referred to as complex tones, that consist of a fundamental frequency (F0) and higher harmonics. In this study we examined single-unit activity recorded in the core (A1) and lateral belt (LB) areas of auditory cortex in two rhesus monkeys as they listened to pure tones and pitch-shifted conspecific vocalizations (“coos”). The latter consisted of complex-tone segments in which F0 was matched to a corresponding pure-tone stimulus. In both animals, neuronal latencies to pure-tone stimuli at the best frequency (BF) were ~10 to 15 ms longer in LB than in A1. This might be expected, since LB is considered to be at a hierarchically higher level than A1. On the other hand, the latency of LB responses to coos was ~10 to 20 ms shorter than to the corresponding pure-tone BF, suggesting facilitation in LB by the harmonics. This latency reduction by coos was not observed in A1, resulting in similar coo latencies in A1 and LB. Multi-peaked neurons were present in both A1 and LB; however, harmonically-related peaks were observed in LB for both early and late response components, whereas in A1 they were observed only for late components. Our results suggest that harmonic features, such as relationships between specific frequency intervals of communication calls, are processed at relatively early stages of the auditory cortical pathway, but preferentially in LB. PMID:25100935

Cochlear Microphonic and Summating Potential Responses from Click-Evoked Auditory Brain Stem Responses in High-Risk and Normal Infants.

PubMed

Hunter, Lisa L; Blankenship, Chelsea M; Gunter, Rebekah G; Keefe, Douglas H; Feeney, M Patrick; Brown, David K; Baroch, Kelly

2018-05-01

Examination of cochlear and neural potentials is necessary to assess sensory and neural status in infants, especially those cared for in neonatal intensive care units (NICU) who have high rates of hyperbilirubinemia and thus are at risk for auditory neuropathy (AN). The purpose of this study was to determine whether recording parameters commonly used in click-evoked auditory brain stem response (ABR) are useful for recording cochlear microphonic (CM) and Wave I in infants at risk for AN. Specifically, we analyzed CM, summating potential (SP), and Waves I, III, and V. The overall aim was to compare latencies and amplitudes of evoked responses in infants cared for in NICUs with infants in a well-baby nursery (WBN), both of which passed newborn hearing screening. This is a prospective study in which infants who passed ABR newborn hearing screening were grouped based on their birth history (WBN and NICU). All infants had normal hearing status when tested with diagnostic ABR at about one month of age, corrected for prematurity. Thirty infants (53 ears) from the WBN [mean corrected age at test = 5.0 weeks (wks.)] and thirty-two infants (59 ears) from the NICU (mean corrected age at test = 5.7 wks.) with normal hearing were included in this study. In addition, two infants were included as comparative case studies, one that was diagnosed with AN and another case that was diagnosed with bilateral sensorineural hearing loss (SNHL). Diagnostic ABR, including click and tone-burst air- and bone-conduction stimuli were recorded. Peak Waves I, III, and V; SP; and CM latency and amplitude (peak to trough) were measured to determine if there were differences in ABR and electrocochleography (ECochG) variables between WBN and NICU infants. No significant group differences were found between WBN and NICU groups for ABR waveforms, CM, or SP, including amplitude and latency values. The majority (75%) of the NICU group had hyperbilirubinemia, but overall, they did not show evidence of effects in their ECochG or ABR responses when tested at about one-month corrected age. These data may serve as a normative sample for NICU and well infant ECochG and ABR latencies at one-month corrected age. Two infant case studies, one diagnosed with AN and another with SNHL demonstrated the complexity of using ECochG and otoacoustic emissions to assess the risk of AN in individual cases. CM and SPs can be readily measured using standard click stimuli in both well and NICU infants. Normative ranges for latency and amplitude are useful for interpreting ECochG and ABR components. Inclusion of ECochG and ABR tests in a test battery that also includes otoacoustic emission and acoustic reflex tests may provide a more refined assessment of the risks of AN and SNHL in infants. American Academy of Audiology.

Comparison of multifocal visual evoked potential, standard automated perimetry and optical coherence tomography in assessing visual pathway in multiple sclerosis patients

PubMed Central

Laron, Michal; Cheng, Han; Zhang, Bin; Schiffman, Jade S.; Tang, Rosa A.; Frishman, Laura J.

2010-01-01

Background Multifocal visual evoked potentials (mfVEP) measure local response amplitude and latency in the field of vision Objective To compare the sensitivity of mfVEP, Humphrey visual field (HVF) and optical coherence tomography (OCT) in detecting visual abnormality in multiple sclerosis (MS) patients. Methods MfVEP, HVF, and OCT (retinal nerve fiber layer [RNFL]) were performed in 47 MS-ON eyes (last optic neuritis (ON) attack ≥ 6 months prior) and 65 MS-no-ON eyes without ON history. Criteria to define an eye as abnormal were: mfVEP 1) amplitude/latency: either amplitude or latency probability plots meeting cluster criteria with 95% specificity 2) amplitude or latency alone (specificity: 97% and 98%, respectively); HVF and OCT, mean deviation and RNFL thickness meeting p < 0.05, respectively. Results MfVEP (amplitude/latency) identified more abnormality in MS-ON eyes (89%) than HVF (72%), OCT (62%), mfVEP amplitude (66%) or latency (67%) alone. 18% of MS-no-ON eyes were abnormal for both mfVEP (amplitude/latency) and HVF compared to 8% with OCT. Agreement between tests ranged from 60% to 79%. MfVEP (amplitude/latency) categorized an additional 15% of MS-ON eyes as abnormal compared to HVF and OCT combined. Conclusions MfVEP, which detects both demyelination (increased latency) and neural degeneration (reduced amplitude) revealed more abnormality than HVF or OCT in MS patients. PMID:20207786

Reliability of the nerve conduction monitor in repeated measures of median and ulnar nerve latencies

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

Washington, I A

According to the Bureau of Labor Statistics, carpal tunnel syndrome (CTS), one of the most rapidly growing work-related injuries, cost American businesses up to $10 billion dollars in medical costs each year (1992). Because conservative therapy can be implemented and CTS is more reversible in it early stages, early detection will not only save industry unnecessary health care costs, but also prevent employees from experiencing debilitating pain and unnecessary surgery. In response to the growing number of cases of CTS, many companies have introduced screening tools to detect early stages of carpal tunnel syndrome. Neurotron Medical (New Jersey) has designedmore » a portable nerve conduction monitor (Nervepace S-200) which measures motor and sensory nerve latencies. The slowing of these latencies is one diagnostic indicator of carpal tunnel syndrome. In this study, we determined the reliability of the Nervepace Monitor in measure ulnar and median nerve latencies during repeated testing. The testing was performed on 28 normal subjects between the ages of 20 and 35 who had no prior symptoms of CTS. They were tested at the same time each day for three consecutive days. Nerve latencies between different ethnic groups and genders were compared. Results show that there was no significant daily variation of the median motor and lunar sensory latencies or the median sensory latencies. No significant differences of latencies was observed among ethnic groups; however, a significant difference of latencies between male and female subjects was observed (p<0.05).« less

[Relationships between electrophysiological characteristic of speech evoked auditory brainstem response and Mandarin monosyllable discriminative ability at different hearing impairment].

PubMed

Fu, Q Y; Liang, Y; Zou, A; Wang, T; Zhao, X D; Wan, J

2016-04-07

To investigate the relationships between electrophysiological characteristic of speech evoked auditory brainstem response(s-ABR) and Mandarin phonetically balanced maximum(PBmax) at different hearing impairment, so as to provide more clues for the mechanism of speech cognitive behavior. Forty-one ears in 41 normal hearing adults(NH), thirty ears in 30 conductive hearing loss patients(CHL) and twenty-seven ears in 27 sensorineural hearing loss patients(SNHL) were included in present study. The speech discrimination scores were obtained by Mandarin phonemic-balanced monosyllable lists via speech audiometric software. Their s-ABRs were recorded with speech syllables /da/ with the intensity of phonetically balanced maximum(PBmax). The electrophysiological characteristic of s-ABR, as well as the relationships between PBmax and s-ABR parameters including latency in time domain, fundamental frequency(F0) and first formant(F1) in frequency domain were analyzed statistically. All subjects completed good speech perception tests and PBmax of CHL and SNHL had no significant difference (P>0.05), but both significantly less than that of NH (P<0.05). While divided the subjects into three groups by 90%

[Visual perception of Kanji characters and complicated figures. II. Visual P300 event-related potentials in patients with mental retardation].

PubMed

Sata, Yoshimi; Inagaki, Masumi; Shirane, Seiko; Kaga, Makiko

2002-11-01

In order to objectively evaluate visual perception of patients with mental retardation (MR), the P300 event-related potentials (ERPs) for visual oddball tasks were recorded in 26 patients and 13 age-matched healthy volunteers. The latency and amplitude of visual P300 in response to the Japanese ideogram stimuli (a pair of familiar Kanji characters or unfamiliar Kanji characters) and a pair of meaningless complicated figures were measured. In almost all MR patients visual P300 was observed, however, the peak latency was significantly prolonged compared to control subjects. There was no significant difference of P300 latency among the three tasks. The distribution pattern of P300 in MR patients was different from that in the controls and the amplitudes in the frontal region was larger in MR patients. The latency decreased with age even in both groups. The developmental change of P300 latency corresponded to developmental age rather than the chronological age. These findings suggest that MR patients have impairment in processing of visual perception. Assessment of P300 latencies to the visual stimuli may be useful as an objective indicator of mental deficit.

Short-Term Adaptive Modification of Dynamic Ocular Accommodation

PubMed Central

Bharadwaj, Shrikant R.; Vedamurthy, Indu; Schor, Clifton M.

2009-01-01

Purpose Indirect observations suggest that the neural control of accommodation may undergo adaptive recalibration in response to age-related biomechanical changes in the accommodative system. However, there has been no direct demonstration of such an adaptive capability. This investigation was conducted to demonstrate short-term adaptation of accommodative step response dynamics to optically induced changes in neuromuscular demands. Methods Repetitive changes in accommodative effort were induced in 15 subjects (18–34 years) with a double-step adaptation paradigm wherein an initial 2-D step change in blur was followed 350 ms later by either a 2-D step increase in blur (increasing-step paradigm) or a 1.75-D step decrease in blur (decreasing-step paradigm). Peak velocity, peak acceleration, and latency of 2-D single-step test responses were assessed before and after 1.5 hours of training with these paradigms. Results Peak velocity and peak acceleration of 2-D step responses increased after adaptation to the increasing-step paradigm (9/12 subjects), and they decreased after adaptation to the decreasing-step paradigm (4/9 subjects). Adaptive changes in peak velocity and peak acceleration generalized to responses that were smaller (1 D) and larger (3 D) than the 2-D adaptation stimulus. The magnitude of adaptation correlated poorly with the subject's age, but it was significantly negatively correlated with the preadaptation dynamics. Response latency decreased after adaptation, irrespective of the direction of adaptation. Conclusions Short-term adaptive changes in accommodative step response dynamics could be induced, at least in some of our subjects between 18 and 34 years, with a directional bias toward increasing rather than decreasing the dynamics. PMID:19255153

Fast and singular muscle responses initiate the startle response of Pantodon buchholzi (Osteoglossomorpha).

PubMed

Starosciak, A K; Kalola, R P; Perkins, K P; Riley, J A; Saidel, W M

2008-01-01

The startle response of Pantodon buchholzi, the African butterfly fish, is a complete or incomplete ballistic jump resulting from abduction of the pectoral fins. This study analyzed the neuromuscular basis for such a jump by recording in vivo electromyograms (emgs) from the muscles of abduction, the muscularis abductor superficialis (MAS) and the muscularis abductor profundus (MAP). The motor neurons innervating the MAS muscle were localized by retrograde transport of biocytin. The latency between stimulus and the evoked emg in the MAS was less than 5 ms; the latency of the MAP was about 6.5 ms. A single emg was recorded per jump. High speed video demonstrated that onset of a startle movement began within 10 ms of the onset of fin abduction. The emg associated with this movement is short (<2 ms) and followed by a variably-shaped, slower and smaller potential of 10-30 ms duration. The brief period between stimulus and startle response of Pantodon suggests a Mauthner neuron-related response, only with the behavior occurring in the vertical plane. The MAS may act only in a startle response, whereas the MAP might have a role in other behaviors. Elicited jumping habituates after a single trial. Electrophysiological evidence is presented indicating that the innervating motor neurons are suppressed for seconds following a stimulus. The neurons innervating the MAS are located at the medullary-spinal cord junction and possess an average radius of approximately 17.9 mum. These fish have been historically described as 'fresh water' flying fish. As a single emg occurs per startle response, repetitive pectoral activity generating flying cannot be supported. Pantodon 'flight' is ballistic. Copyright 2007 S. Karger AG, Basel.

Neuronal responses to face-like stimuli in the monkey pulvinar.

PubMed

Nguyen, Minh Nui; Hori, Etsuro; Matsumoto, Jumpei; Tran, Anh Hai; Ono, Taketoshi; Nishijo, Hisao

2013-01-01

The pulvinar nuclei appear to function as the subcortical visual pathway that bypasses the striate cortex, rapidly processing coarse facial information. We investigated responses from monkey pulvinar neurons during a delayed non-matching-to-sample task, in which monkeys were required to discriminate five categories of visual stimuli [photos of faces with different gaze directions, line drawings of faces, face-like patterns (three dark blobs on a bright oval), eye-like patterns and simple geometric patterns]. Of 401 neurons recorded, 165 neurons responded differentially to the visual stimuli. These visual responses were suppressed by scrambling the images. Although these neurons exhibited a broad response latency distribution, face-like patterns elicited responses with the shortest latencies (approximately 50 ms). Multidimensional scaling analysis indicated that the pulvinar neurons could specifically encode face-like patterns during the first 50-ms period after stimulus onset and classify the stimuli into one of the five different categories during the next 50-ms period. The amount of stimulus information conveyed by the pulvinar neurons and the number of stimulus-differentiating neurons were consistently higher during the second 50-ms period than during the first 50-ms period. These results suggest that responsiveness to face-like patterns during the first 50-ms period might be attributed to ascending inputs from the superior colliculus or the retina, while responsiveness to the five different stimulus categories during the second 50-ms period might be mediated by descending inputs from cortical regions. These findings provide neurophysiological evidence for pulvinar involvement in social cognition and, specifically, rapid coarse facial information processing. © 2012 Federation of European Neuroscience Societies and Blackwell Publishing Ltd.

Sleep-stage sequencing of sleep-onset REM periods in MSLT predicts treatment response in patients with narcolepsy.

PubMed

Drakatos, Panagis; Patel, Kishankumar; Thakrar, Chiraag; Williams, Adrian J; Kent, Brian D; Leschziner, Guy D

2016-04-01

Current treatment recommendations for narcolepsy suggest that modafinil should be used as a first-line treatment ahead of conventional stimulants or sodium oxybate. In this study, performed in a tertiary sleep disorders centre, treatment responses were examined following these recommendations, and the ability of sleep-stage sequencing of sleep-onset rapid eye movement periods in the multiple sleep latency test to predict treatment response. Over a 3.5-year period, 255 patients were retrospectively identified in the authors' database as patients diagnosed with narcolepsy, type 1 (with cataplexy) or type 2 (without) using clinical and polysomnographic criteria. Eligible patients were examined in detail, sleep study data were abstracted and sleep-stage sequencing of sleep-onset rapid eye movement periods were analysed. Response to treatment was graded utilizing an internally developed scale. Seventy-five patients were included (39% males). Forty (53%) were diagnosed with type 1 narcolepsy with a mean follow-up of 2.37 ± 1.35 years. Ninety-seven percent of the patients were initially started on modafinil, and overall 59% reported complete response on the last follow-up. Twenty-nine patients (39%) had the sequence of sleep stage 1 or wake to rapid eye movement in all of their sleep-onset rapid eye movement periods, with most of these diagnosed as narcolepsy type 1 (72%). The presence of this specific sleep-stage sequence in all sleep-onset rapid eye movement periods was associated with worse treatment response (P = 0.0023). Sleep-stage sequence analysis of sleep-onset rapid eye movement periods in the multiple sleep latency test may aid the prediction of treatment response in narcoleptics and provide a useful prognostic tool in clinical practice, above and beyond their classification as narcolepsy type 1 or 2. © 2015 European Sleep Research Society.

Automated cortical auditory evoked potentials threshold estimation in neonates.

PubMed

Oliveira, Lilian Sanches; Didoné, Dayane Domeneghini; Durante, Alessandra Spada

2018-02-02

The evaluation of Cortical Auditory Evoked Potential has been the focus of scientific studies in infants. Some authors have reported that automated response detection is effective in exploring these potentials in infants, but few have reported their efficacy in the search for thresholds. To analyze the latency, amplitude and thresholds of Cortical Auditory Evoked Potential using an automatic response detection device in a neonatal population. This is a cross-sectional, observational study. Cortical Auditory Evoked Potentials were recorded in response to pure-tone stimuli of the frequencies 500, 1000, 2000 and 4000Hz presented in an intensity range between 0 and 80dB HL using a single channel recording. P1 was performed in an exclusively automated fashion, using Hotelling's T 2 statistical test. The latency and amplitude were obtained manually by three examiners. The study comprised 39 neonates up to 28 days old of both sexes with presence of otoacoustic emissions and no risk factors for hearing loss. With the protocol used, Cortical Auditory Evoked Potential responses were detected in all subjects at high intensity and thresholds. The mean thresholds were 24.8±10.4dB NA, 25±9.0dB NA, 28±7.8dB NA and 29.4±6.6dB HL for 500, 1000, 2000 and 4000Hz, respectively. Reliable responses were obtained in the assessment of cortical auditory potentials in the neonates assessed with a device for automatic response detection. Copyright © 2018 Associação Brasileira de Otorrinolaringologia e Cirurgia Cérvico-Facial. Published by Elsevier Editora Ltda. All rights reserved.

A comparison of the brainstem auditory evoked response in healthy ears of unilaterally deaf dogs and bilaterally hearing dogs.

PubMed

Plonek, M; Nicpoń, J; Kubiak, K; Wrzosek, M

2017-03-01

Auditory plasticity in response to unilateral deafness has been reported in various animal species. Subcortical changes occurring in unilaterally deaf young dogs using the brainstem auditory evoked response have not been evaluated yet. The aim of this study was to assess the brainstem auditory evoked response findings in dogs with unilateral hearing loss, and compare them with recordings obtained from healthy dogs. Brainstem auditory evoked responses (amplitudes and latencies of waves I, II, III, V, the V/I wave amplitude ratio, wave I-V, I-III and III-V interpeak intervals) were studied retrospectively in forty-six privately owned dogs, which were either unilaterally deaf or had bilateral hearing. The data obtained from the hearing ears in unilaterally deaf dogs were compared to values obtained from their healthy littermates. Statistically significant differences in the amplitude of wave III and the V/I wave amplitude ratio at 75 dB nHL were found between the group of unilaterally deaf puppies and the control group. The recordings of dogs with single-sided deafness were compared, and the results showed no statistically significant differences in the latencies and amplitudes of the waves between left- (AL) and right-sided (AR) deafness. The recordings of the brainstem auditory evoked response in canines with unilateral inborn deafness in this study varied compared to recordings from healthy dogs. Future studies looking into electrophysiological assessment of hearing in conjunction with imaging modalities to determine subcortical auditory plasticity and auditory lateralization in unilaterally deaf dogs are warranted.

Magnetoencephalography reveals altered auditory information processing in youth with obsessive-compulsive disorder.

PubMed

Korostenskaja, Milena; Harris, Elana; Giovanetti, Cathy; Horn, Paul; Wang, Yingying; Rose, Douglas; Fujiwara, Hisako; Xiang, Jing

2013-05-30

Patients with obsessive-compulsive disorder (OCD) often report sensory intolerances which may lead to significant functional impairment. This study used auditory evoked fields (AEFs) to address the question of whether neural correlates of sensory auditory information processing differ in youth with OCD compared with healthy comparison subjects (HCS). AEFs, recorded with a whole head 275-channel magnetoencephalography system, were elicited in response to binaural auditory stimuli from 10 pediatric subjects with OCD (ages 8-13, mean 11 years, 6 males) and 10 age- and gender-matched HCS. Three major neuromagnetic responses were studied: M70 (60-80 ms), M100 (90-120 ms), and M150 (130-190 ms). When compared with HCS, subjects with OCD demonstrated delayed latency of the M100 response. In subjects with OCD the amplitude of the M100 and M150 responses was significantly greater in the right hemisphere compared with the left hemisphere. Current results suggest that when compared with HCS, subjects with OCD have altered auditory information processing, evident from the delayed latency of the M100 response, which is thought to be associated with the encoding of physical stimulus characteristics. Interhemispheric asymmetry with increased M100 and M150 amplitudes over the right hemisphere compared with the left hemisphere was found in young OCD subjects. These results should be interpreted with caution due to the high variability rate of responses in both HCS and OCD subjects, as well as the possible effect of medication in OCD subjects. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

Deletion of Fmr1 Alters Function and Synaptic Inputs in the Auditory Brainstem

PubMed Central

Rotschafer, Sarah E.; Marshak, Sonya; Cramer, Karina S.

2015-01-01

Fragile X Syndrome (FXS), a neurodevelopmental disorder, is the most prevalent single-gene cause of autism spectrum disorder. Autism has been associated with impaired auditory processing, abnormalities in the auditory brainstem response (ABR), and reduced cell number and size in the auditory brainstem nuclei. FXS is characterized by elevated cortical responses to sound stimuli, with some evidence for aberrant ABRs. Here, we assessed ABRs and auditory brainstem anatomy in Fmr1 -/- mice, an animal model of FXS. We found that Fmr1 -/- mice showed elevated response thresholds to both click and tone stimuli. Amplitudes of ABR responses were reduced in Fmr1 -/- mice for early peaks of the ABR. The growth of the peak I response with sound intensity was less steep in mutants that in wild type mice. In contrast, amplitudes and response growth in peaks IV and V did not differ between these groups. We did not observe differences in peak latencies or in interpeak latencies. Cell size was reduced in Fmr1 -/- mice in the ventral cochlear nucleus (VCN) and in the medial nucleus of the trapezoid body (MNTB). We quantified levels of inhibitory and excitatory synaptic inputs in these nuclei using markers for presynaptic proteins. We measured VGAT and VGLUT immunolabeling in VCN, MNTB, and the lateral superior olive (LSO). VGAT expression in MNTB was significantly greater in the Fmr1 -/- mouse than in wild type mice. Together, these observations demonstrate that FXS affects peripheral and central aspects of hearing and alters the balance of excitation and inhibition in the auditory brainstem. PMID:25679778

Bioanalytical techniques for detecting biomarkers of response to human asbestos exposure.

PubMed

Mesaros, Clementina; Worth, Andrew J; Snyder, Nathaniel W; Christofidou-Solomidou, Melpo; Vachani, Anil; Albelda, Steven M; Blair, Ian A

2015-01-01

Asbestos exposure is known to cause lung cancer and mesothelioma and its health and economic impacts have been well documented. The exceptionally long latency periods of most asbestos-related diseases have hampered preventative and precautionary steps thus far. We aimed to summarize the state of knowledge on biomarkers of response to asbestos exposure. Asbestos is not present in human biological fluids; rather it is inhaled and trapped in lung tissue. Biomarkers of response, which reflect a change in biologic function in response to asbestos exposure, are analyzed. Several classes of molecules have been studied and evaluated for their potential utility as biomarkers of asbestos exposure. These studies range from small molecule oxidative stress biomarkers to proteins involved in immune responses.

Bioanalytical techniques for detecting biomarkers of response to human asbestos exposure

PubMed Central

Mesaros, Clementina; Worth, Andrew J; Snyder, Nathaniel W; Christofidou-Solomidou, Melpo; Vachani, Anil; Albelda, Steven M; Blair, Ian A

2015-01-01

Asbestos exposure is known to cause lung cancer and mesothelioma and its health and economic impacts have been well documented. The exceptionally long latency periods of most asbestos-related diseases have hampered preventative and precautionary steps thus far. We aimed to summarize the state of knowledge on biomarkers of response to asbestos exposure. Asbestos is not present in human biological fluids; rather it is inhaled and trapped in lung tissue. Biomarkers of response, which reflect a change in biologic function in response to asbestos exposure, are analyzed. Several classes of molecules have been studied and evaluated for their potential utility as biomarkers of asbestos exposure. These studies range from small molecule oxidative stress biomarkers to proteins involved in immune responses. PMID:26039812

Emotional organization of autobiographical memory.

PubMed

Schulkind, Matthew D; Woldorf, Gillian M

2005-09-01

The emotional organization of autobiographical memory was examined by determining whether emotional cues would influence autobiographical retrieval in younger and older adults. Unfamiliar musical cues that represented orthogonal combinations of positive and negative valence and high and low arousal were used. Whereas cue valence influenced the valence of the retrieved memories, cue arousal did not affect arousal ratings. However, high-arousal cues were associated with reduced response latencies. A significant bias to report positive memories was observed, especially for the older adults, but neither the distribution of memories across the life span nor response latencies varied across memories differing in valence or arousal. These data indicate that emotional information can serve as effective cues for autobiographical memories and that autobiographical memories are organized in terms of emotional valence but not emotional arousal. Thus, current theories of autobiographical memory must be expanded to include emotional valence as a primary dimension of organization.

The precise time course of lexical activation: MEG measurements of the effects of frequency, probability, and density in lexical decision.

PubMed

Stockall, Linnaea; Stringfellow, Andrew; Marantz, Alec

2004-01-01

Visually presented letter strings consistently yield three MEG response components: the M170, associated with letter-string processing (Tarkiainen, Helenius, Hansen, Cornelissen, & Salmelin, 1999); the M250, affected by phonotactic probability, (Pylkkänen, Stringfellow, & Marantz, 2002); and the M350, responsive to lexical frequency (Embick, Hackl, Schaeffer, Kelepir, & Marantz, 2001). Pylkkänen et al. found evidence that the M350 reflects lexical activation prior to competition among phonologically similar words. We investigate the effects of lexical and sublexical frequency and neighborhood density on the M250 and M350 through orthogonal manipulation of phonotactic probability, density, and frequency. The results confirm that probability but not density affects the latency of the M250 and M350; however, an interaction between probability and density on M350 latencies suggests an earlier influence of neighborhoods than previously reported.

Control of Task Sequences: What is the Role of Language?

PubMed Central

Mayr, Ulrich; Kleffner, Killian; Kikumoto, Atsushi; Redford, Melissa A.

2015-01-01

It is almost a truism that language aids serial-order control through self-cuing of upcoming sequential elements. We measured speech onset latencies as subjects performed hierarchically organized task sequences while "thinking aloud" each task label. Surprisingly, speech onset latencies and response times (RTs) were highly synchronized, a pattern that is not consistent with the hypothesis that speaking aids proactive retrieval of upcoming sequential elements during serial-order control. We also found that when instructed to do so, participants were able to speak task labels prior to presentation of response-relevant stimuli and that this substantially reduced RT signatures of retrieval—however at the cost of more sequencing errors. Thus, while proactive retrieval is possible in principle, in natural situations it seems to be prevented through a strong, "gestalt-like" tendency to synchronize speech and action. We suggest that this tendency may support context updating rather than proactive control. PMID:24274386

Response-dependent dynamics of cell-specific inhibition in cortical networks in vivo

PubMed Central

El-Boustani, Sami; Sur, Mriganka

2014-01-01

In the visual cortex, inhibitory neurons alter the computations performed by target cells via combination of two fundamental operations, division and subtraction. The origins of these operations have been variously ascribed to differences in neuron classes, synapse location or receptor conductances. Here, by utilizing specific visual stimuli and single optogenetic probe pulses, we show that the function of parvalbumin-expressing and somatostatin-expressing neurons in mice in vivo is governed by the overlap of response timing between these neurons and their targets. In particular, somatostatin-expressing neurons respond at longer latencies to small visual stimuli compared with their target neurons and provide subtractive inhibition. With large visual stimuli, however, they respond at short latencies coincident with their target cells and switch to provide divisive inhibition. These results indicate that inhibition mediated by these neurons is a dynamic property of cortical circuits rather than an immutable property of neuronal classes. PMID:25504329

Functional connectivity between right and left mesial temporal structures.

PubMed

Lacuey, Nuria; Zonjy, Bilal; Kahriman, Emine S; Kaffashi, Farhad; Miller, Jonathan; Lüders, Hans O

2015-09-01

The aim of this study is to investigate functional connectivity between right and left mesial temporal structures using cerebrocerebral evoked potentials. We studied seven patients with drug-resistant focal epilepsy who were explored with stereotactically implanted depth electrodes in bilateral hippocampi. In all patients cerebrocerebral evoked potentials evoked by stimulation of the fornix were evaluated as part of a research project assessing fornix stimulation for control of hippocampal seizures. Stimulation of the fornix elicited responses in the ipsilateral hippocampus in all patients with a mean latency of 4.6 ms (range 2-7 ms). Two patients (29 %) also had contralateral hippocampus responses with a mean latency of 7.5 ms (range 5-12 ms) and without involvement of the contralateral temporal neocortex or amygdala. This study confirms the existence of connections between bilateral mesial temporal structures in some patients and explains seizure discharge spreading between homotopic mesial temporal structures without neocortical involvement.

Near real time/low latency data collection for climate warming manipulations and an elevated CO2 SPRUCE experiment

NASA Astrophysics Data System (ADS)

Krassovski, M.; Hanson, P. J.; Riggs, J. S.; Nettles, W. R., IV

2017-12-01

Climate change studies are one of the most important aspects of modern science and related experiments are getting bigger and more complex. One such experiment is the Spruce and Peatland Responses Under Climatic and Environmental Change experiment (SPRUCE, http://mnspruce.ornl.gov) conducted in in northern Minnesota, 40 km north of Grand Rapids, in the USDA Forest Service Marcell Experimental Forest (MEF). The SPRUCE experimental mission is to assess ecosystem-level biological responses of vulnerable, high carbon terrestrial ecosystems to a range of climate warming manipulations and an elevated CO2 atmosphere. This manipulation experiment generates a lot of observational data and requires a reliable onsite data collection system, dependable methods to transfer data to a robust scientific facility, and real-time monitoring capabilities. This presentation shares our experience of establishing near real time/low latency data collection and monitoring system using satellite communication.

Afterimage induced neural activity during emotional face perception.

PubMed

Cheal, Jenna L; Heisz, Jennifer J; Walsh, Jennifer A; Shedden, Judith M; Rutherford, M D

2014-02-26

The N170 response differs when positive versus negative facial expressions are viewed. This neural response could be associated with the perception of emotions, or some feature of the stimulus. We used an aftereffect paradigm to clarify. Consistent with previous reports of emotional aftereffects, a neutral face was more likely to be described as happy following a sad face adaptation, and more likely to be described as sad following a happy face adaptation. In addition, similar to previous observations with actual emotional faces, we found differences in the latency of the N170 elicited by the neutral face following sad versus happy face adaptation, demonstrating that the emotion-specific effect on the N170 emerges even when emotion expressions are perceptually different but physically identical. The re-entry of emotional information from other brain regions may be driving the emotional aftereffects and the N170 latency differences. Copyright © 2014 Elsevier B.V. All rights reserved.

The Neural Representation of Consonant-Vowel Transitions in Adults Who Wear Hearing Aids

PubMed Central

Tremblay, Kelly L.; Kalstein, Laura; Billings, Cuttis J.; Souza, Pamela E.

2006-01-01

Hearing aids help compensate for disorders of the ear by amplifying sound; however, their effectiveness also depends on the central auditory system's ability to represent and integrate spectral and temporal information delivered by the hearing aid. The authors report that the neural detection of time-varying acoustic cues contained in speech can be recorded in adult hearing aid users using the acoustic change complex (ACC). Seven adults (50–76 years) with mild to severe sensorineural hearing participated in the study. When presented with 2 identifiable consonant-vowel (CV) syllables (“shee” and “see”), the neural detection of CV transitions (as indicated by the presence of a P1-N1-P2 response) was different for each speech sound. More specifically, the latency of the evoked neural response coincided in time with the onset of the vowel, similar to the latency patterns the authors previously reported in normal-hearing listeners. PMID:16959736

Generation of human auditory steady-state responses (SSRs). II: Addition of responses to individual stimuli.

PubMed

Santarelli, R; Maurizi, M; Conti, G; Ottaviani, F; Paludetti, G; Pettorossi, V E

1995-03-01

In order to investigate the generation of the 40 Hz steady-state response (SSR), auditory potentials evoked by clicks were recorded in 16 healthy subjects in two stimulating conditions. Firstly, repetition rates of 7.9 and 40 Hz were used to obtain individual middle latency responses (MLRs) and 40 Hz-SSRs, respectively. In the second condition, eight click trains were presented at a 40 Hz repetition rate and an inter-train interval of 126 ms. We extracted from the whole train response: (1) the response-segment taking place after the last click of the train (last click response, LCR), (2) a modified LCR (mLCR) obtained by clearing the LCR from the amplitude enhancement due to the overlapping of the responses to the clicks preceding the last within the stimulus train. In comparison to MLRs, the most relevant feature of the evoked activity following the last click of the train (LCRs, mLCRs) was the appearance in the 50-110 ms latency range of one (in 11 subjects) or two (in 2 subjects) additional positive-negative deflections having the same periodicity as that of MLR waves. The grand average (GA) of the 40 Hz-SSRs was compared with three predictions synthesized by superimposing: (1) the GA of MLRs, (2) the GA of LCRs, (3) the GA of mLCRs. Both the MLR and mLCR predictions reproduced the recorded signal in amplitude while the LCR prediction amplitude resulted almost twice that of the 40 Hz-SSR. With regard to the phase, the MLR, LCR and mLCR closely predicted the recorded signal. Our findings confirm the effectiveness of the linear addition mechanism in the generation of the 40 Hz-SSR. However the responses to individual stimuli within the 40 Hz-SSR differ from MLRs because of additional periodic activity. These results suggest that phenomena related to the resonant frequency of the activated system may play a role in the mechanisms which interact to generate the 40 Hz-SSR.

Primary display latency criteria based on flying qualities and performance data

NASA Technical Reports Server (NTRS)

Funk, John D., Jr.; Beck, Corin P.; Johns, John B.

1993-01-01

With a pilots' increasing use of visual cue augmentation, much requiring extensive pre-processing, there is a need to establish criteria for new avionics/display design. The timeliness and synchronization of the augmented cues is vital to ensure the performance quality required for precision mission task elements (MTEs) where augmented cues are the primary source of information to the pilot. Processing delays incurred while transforming sensor-supplied flight information into visual cues are unavoidable. Relationships between maximum control system delays and associated flying qualities levels are documented in MIL-F-83300 and MIL-F-8785. While cues representing aircraft status may be just as vital to the pilot as prompt control response for operations in instrument meteorological conditions, presently, there are no specification requirements on avionics system latency. To produce data relating avionics system latency to degradations in flying qualities, the Navy conducted two simulation investigations. During the investigations, flying qualities and performance data were recorded as simulated avionics system latency was varied. Correlated results of the investigation indicates that there is a detrimental impact of latency on flying qualities. Analysis of these results and consideration of key factors influencing their application indicate that: (1) Task performance degrades and pilot workload increases as latency is increased. Inconsistency in task performance increases as latency increases. (2) Latency reduces the probability of achieving Level 1 handling qualities with avionics system latency as low as 70 ms. (3) The data suggest that the achievement of desired performance will be ensured only at display latency values below 120 ms. (4) These data also suggest that avoidance of inadequate performance will be ensured only at display latency values below 150 ms.

Source-reconstruction of event-related fields reveals hyperfunction and hypofunction of cortical circuits in antipsychotic-naive, first-episode schizophrenia patients during Mooney face processing.

PubMed

Rivolta, Davide; Castellanos, Nazareth P; Stawowsky, Cerisa; Helbling, Saskia; Wibral, Michael; Grützner, Christine; Koethe, Dagmar; Birkner, Katharina; Kranaster, Laura; Enning, Frank; Singer, Wolf; Leweke, F Markus; Uhlhaas, Peter J

2014-04-23

Schizophrenia is characterized by dysfunctions in neural circuits that can be investigated with electrophysiological methods, such as EEG and MEG. In the present human study, we examined event-related fields (ERFs), in a sample of medication-naive, first-episode schizophrenia (FE-ScZ) patients (n = 14) and healthy control participants (n = 17) during perception of Mooney faces to investigate the integrity of neuromagnetic responses and their experience-dependent modification. ERF responses were analyzed for M100, M170, and M250 components at the sensor and source levels. In addition, we analyzed peak latency and adaptation effects due to stimulus repetition. FE-ScZ patients were characterized by significantly impaired sensory processing, as indicated by a reduced discrimination index (A'). At the sensor level, M100 and M170 responses in FE-ScZ were within the normal range, whereas the M250 response was impaired. However, source localization revealed widespread elevated activity for M100 and M170 in FE-ScZ and delayed peak latencies for the M100 and M250 responses. In addition, M170 source activity in FE-ScZ was not modulated by stimulus repetitions. The present findings suggest that neural circuits in FE-ScZ may be characterized by a disturbed balance between excitation and inhibition that could lead to a failure to gate information flow and abnormal spreading of activity, which is compatible with dysfunctional glutamatergic neurotransmission.

Improving the Reliability of Student Scores from Speeded Assessments: An Illustration of Conditional Item Response Theory Using a Computer-Administered Measure of Vocabulary

ERIC Educational Resources Information Center

Petscher, Yaacov; Mitchell, Alison M.; Foorman, Barbara R.

2015-01-01

A growing body of literature suggests that response latency, the amount of time it takes an individual to respond to an item, may be an important factor to consider when using assessment data to estimate the ability of an individual. Considering that tests of passage and list fluency are being adapted to a computer administration format, it is…

A primary cell model of HIV-1 latency that uses activation through the T cell receptor and return to quiescence to establish latent infection

PubMed Central

Kim, Michelle; Hosmane, Nina N.; Bullen, C. Korin; Capoferri, Adam; Yang, Hung-Chih; Siliciano, Janet D.; Siliciano, Robert F.

2015-01-01

A mechanistic understanding of HIV-1 latency depends upon a model system that recapitulates the in vivo condition of latently infected, resting CD4+ T lymphocytes. Latency appears to be established after activated CD4+ T cells, the principal targets of HIV-1 infection, become productively infected and survive long enough to return to a resting memory state in which viral expression is inhibited by changes in the cellular environment. This protocol describes an ex vivo primary cell system that is generated under conditions that reflect the in vivo establishment of latency. Creation of these latency model cells takes 12 weeks and, once established, the cells can be maintained and used for several months. The resulting cell population contains both uninfected and latently infected cells. This primary cell model can be used to perform drug screens, study CTL responses to HIV-1, compare viral alleles, or to expand the ex vivo lifespan of cells from HIV-1 infected individuals for extended study. PMID:25375990

User Needs and Assessing the Impact of Low Latency NASA Earth Observation Data Availability on Societal Benefit

NASA Technical Reports Server (NTRS)

Brown, Molly E.; Carroll, Mark L.; Escobar, Vanessa M.

2014-01-01

Since the advent of NASA's Earth Observing System, knowledge of the practical benefits of Earth science data has grown considerably. The community using NASA Earth science observations in applications has grown significantly, with increasing sophistication to serve national interests. Data latency, or how quickly communities receive science observations after acquisition, can have a direct impact on the applications and usability of the information. This study was conducted to determine how users are incorporating NASA data into applications and operational processes to benefit society beyond scientific research, as well as to determine the need for data latency of less than 12 h. The results of the analysis clearly show the significant benefit to society of serving the needs of the agricultural, emergency response, environmental monitoring and weather communities who use rapidly delivered, accurate Earth science data. The study also showed the potential of expanding the communities who use low latency NASA science data products to provide new ways of transforming data into information. These benefits can be achieved with a clear and consistent NASA policy on product latency.

Neural basis of major depressive disorder: Beyond monoamine hypothesis.

PubMed

Boku, Shuken; Nakagawa, Shin; Toda, Hiroyuki; Hishimoto, Akitoyo

2018-01-01

The monoamine hypothesis has been accepted as the most common hypothesis of major depressive disorder (MDD) for a long period because of its simplicity and understandability. Actually, most currently used antidepressants have been considered to act based on the monoamine hypothesis. However, an important problem of the monoamine hypothesis has been pointed out as follows: it fails to explain the latency of response to antidepressants. In addition, many patients with MDD have remained refractory to currently used antidepressants. Therefore, monoamine-alternate hypotheses are required to explain the latency of response to antidepressants. Such hypotheses have been expected to contribute to identifying hopeful new therapeutic targets for MDD. Past studies have revealed that the volume of the hippocampus is decreased in patients with MDD, which is likely caused by the failure of the hypothalamic-pituitary-adrenal axis and following elevation of glucocorticoids. Two hypotheses have been proposed to explain the volume of the hippocampus: (i) the neuroplasticity hypothesis; and (ii) the neurogenesis hypothesis. The neuroplasticity hypothesis explains how the hippocampal volume is decreased by the morphological changes of hippocampal neurons, such as the shortening length of dendrites and the decreased number and density of spines. The neurogenesis hypothesis explains how the hippocampal volume is decreased by the decrease of neurogenesis in the hippocampal dentate gyrus. These hypotheses are able to explain the latency of response to antidepressants. In this review, we first overview how the neuroplasticity and neurogenesis hypotheses have been developed. We then describe the details of these hypotheses. © 2017 The Authors. Psychiatry and Clinical Neurosciences © 2017 Japanese Society of Psychiatry and Neurology.

[Electrical stimulation of the facial nerve with a prognostic function in parotid surgery].

PubMed

García-Losarcos, N; González-Hidalgo, M; Franco-Carcedo, C; Poch-Broto, J

Continuous electromyography during parotidectomies and direct stimulation of the facial nerve as an intraoperative identification technique significantly lower the rate of post-operative morbidity. To determine the usefulness of intra-operative neurophysiological parameters registered by means of electrical stimulation of the facial nerve as values capable of predicting the type of lesion and the functional prognosis. Our sample consisted of a correlative series of 20 cases of monitored parotidectomies. Post-operative facial functioning, type of lesion and its prognosis were compared with the variations in latency/amplitude of the muscle response between two stimulations of the facial nerve before and after resection, as well as in the absence or presence of muscle response to stimulation after resection. All the patients except one presented motor evoked potentials (MEP) to stimulation after resection. There was no facial damage following the operation in 55% of patients and 45% presented some kind of paresis. The 21% drop in the amplitude of the intra-operative MEP and the mean increase in latency of 13.5% correspond to axonal and demyelinating insult, respectively, with a mean recovery time of three and six months. The only case of absence of response to the post-resection stimulation presented permanent paresis. The presence of MEP following resection does not ensure that functioning of the nerve remains undamaged. Nevertheless, it can be considered a piece of data that suggests a lower degree of compromise, if it is present, and a better prognosis. The variations in latency and amplitude of the MEP tend to be intra-operative parameters that indicate the degree of compromise and functional prognosis.

Potential effects of reward and loss avoidance in overweight adolescents

PubMed Central

Reyes, Sussanne; Peirano, Patricio; Luna, Beatriz; Lozoff, Betsy; Algarín, Cecilia

2015-01-01

Background Reward system and inhibitory control are brain functions that exert an influence on eating behavior regulation. We studied the differences in inhibitory control and sensitivity to reward and loss avoidance between overweight/obese and normal-weight adolescents. Methods We assessed 51 overweight/obese and 52 normal-weight 15-y-old Chilean adolescents. The groups were similar regarding sex and intelligence quotient. Using Antisaccade and Incentive tasks, we evaluated inhibitory control and the effect of incentive trials (neutral, loss avoidance, and reward) on generating correct and incorrect responses (latency and error rate). Results Compared to normal-weight group participants, overweight/obese adolescents showed shorter latency for incorrect antisaccade responses (186.0 (95% CI: 176.8–195.2) vs. 201.3 ms (95% CI: 191.2–211.5), P < 0.05) and better performance reflected by lower error rate in incentive trials (43.6 (95% CI: 37.8–49.4) vs. 53.4% (95% CI: 46.8–60.0), P < 0.05). Overweight/obese adolescents were more accurate on loss avoidance (40.9 (95% CI: 33.5–47.7) vs. 49.8% (95% CI: 43.0–55.1), P < 0.05) and reward (41.0 (95% CI: 34.5–47.5) vs. 49.8% (95% CI: 43.0–55.1), P < 0.05) compared to neutral trials. Conclusion Overweight/obese adolescents showed shorter latency for incorrect responses and greater accuracy in reward and loss avoidance trials. These findings could suggest that an imbalance of inhibition and reward systems influence their eating behavior. PMID:25927543

Static and Dynamic Measurements of Accommodation in Individuals with Down Syndrome

PubMed Central

Manny, Ruth E.; Glasser, Adrian; Stuebing, Karla K.

2011-01-01

Purpose. To identify whether static and dynamic aspects of accommodation other than accuracy are deficient in individuals with Down syndrome (DS) and whether poor accommodation is related to sensory or motor pathway deficits. Methods. Static aspects of accommodation (maximum accommodative response and lag) were measured with an autorefractor for both proximal and minus lens demands. Dynamic aspects of accommodation (latency, peak velocity, microfluctuations) were recorded at 30 Hz with a custom-built photorefractor as subjects viewed a movie switching between 11 m and 50, 33, 25, or 20 cm. Thirty-six subjects with DS were recruited (age 3 to 39 years), and 24 (67%) had useable responses for at least one study measurement for comparison with 140 controls (3 to 40 years) from a previously published cohort. Results. DS subjects had lower maximum accommodative responses (mean = 2.52 ± 1.66 D) and higher lags (1.81 ± 1.30 D for 33 cm demand) than controls for both proximal and minus lens stimuli. DS subjects had greater microfluctuations (one-way ANCOVA, P < 0.001), and a small percentage of the total number of latency measurements (17% accommodative and 16% disaccommodative) were longer than controls. Peak velocities of accommodation and disaccommodation were not different between groups (one-way ANCOVA, P = 0.143). Conclusions. Peak velocities of accommodation and disaccommodation (primarily motor aspects) did not differ between controls and DS subjects; however, latencies (primarily sensory) and microfluctuations (combined motor and sensory) were poorer in DS subjects. These results suggest that poor accommodative accuracy in individuals with DS may be predominantly related to sensory deficits. PMID:20739471

[Latency problems with smothering using soft cover].

PubMed

Wirth, Ingo; Strauch, Hansjürg; Schmeling, Andreas

2007-01-01

Smothering by covering the respiratory orifices with soft material is one of the rarely established forms of mechanically induced death by asphyxia. An important reason of latency is that this kind of homicide leaves almost no traces. The two described cases from the autopsy material of the Institute of Legal Medicine in Berlin (CCM) show the limits of medico-legal interpretation and the resulting special responsibility of the investigator. In the first case the defendant denied the offence and was acquitted of the charge, while in the second case the self-confessed offender was convicted.

Effect of indocyanine green angiography using infrared fundus camera on subsequent dark adaptation and electroretinogram.

PubMed

Wen, Feng; Yu, Minzhong; Wu, Dezheng; Ma, Juanmei; Wu, Lezheng

2002-07-01

To observe the effect of indocyanine green angiography (ICGA) with infrared fundus camera on subsequent dark adaptation and the Ganzfeld electroretinogram (ERG), the ERGs of 38 eyes with different retinal diseases were recorded before and after ICGA during a 40-min dark adaptation period. ICGA was performed with Topcon 50IA retina camera. Ganzfeld ERG was recorded with Neuropack II evoked response recorder. The results showed that ICGA did not affect the latencies and the amplitudes in ERG of rod response, cone response and mixed maximum response (p>0.05). It suggests that ICGA using infrared fundus camera could be performed prior to the recording of the Ganzfeld ERG.

F-wave decomposition for time of arrival profile estimation.

PubMed

Han, Zhixiu; Kong, Xuan

2007-01-01

F-waves are distally recorded muscle responses that result from "backfiring" of motor neurons following stimulation of peripheral nerves. Each F-wave response is a superposition of several motor unit responses (F-wavelets). Initial deflection of the earliest F-wavelet defines the traditional F-wave latency (FWL) and earlier F-wavelet may mask F-wavelets traveling along slower (and possibly diseased) fibers. Unmasking the time of arrival (TOA) of late F-wavelets could improve the diagnostic value of the F-waves. An algorithm for F-wavelet decomposition is presented, followed by results of experimental data analysis.

Low-frequency repetitive transcranial magnetic stimulation (rTMS) affects event-related potential measures of novelty processing in autism.

PubMed

Sokhadze, Estate; Baruth, Joshua; Tasman, Allan; Mansoor, Mehreen; Ramaswamy, Rajesh; Sears, Lonnie; Mathai, Grace; El-Baz, Ayman; Casanova, Manuel F

2010-06-01

In our previous study on individuals with autism spectrum disorder (ASD) (Sokhadze et al., Appl Psychophysiol Biofeedback 34:37-51, 2009a) we reported abnormalities in the attention-orienting frontal event-related potentials (ERP) and the sustained-attention centro-parietal ERPs in a visual oddball experiment. These results suggest that individuals with autism over-process information needed for the successful differentiation of target and novel stimuli. In the present study we examine the effects of low-frequency, repetitive Transcranial Magnetic Stimulation (rTMS) on novelty processing as well as behavior and social functioning in 13 individuals with ASD. Our hypothesis was that low-frequency rTMS application to dorsolateral prefrontal cortex (DLFPC) would result in an alteration of the cortical excitatory/inhibitory balance through the activation of inhibitory GABAergic double bouquet interneurons. We expected to find post-TMS differences in amplitude and latency of early and late ERP components. The results of our current study validate the use of low-frequency rTMS as a modulatory tool that altered the disrupted ratio of cortical excitation to inhibition in autism. After rTMS the parieto-occipital P50 amplitude decreased to novel distracters but not to targets; also the amplitude and latency to targets increased for the frontal P50 while decreasing to non-target stimuli. Low-frequency rTMS minimized early cortical responses to irrelevant stimuli and increased responses to relevant stimuli. Improved selectivity in early cortical responses lead to better stimulus differentiation at later-stage responses as was made evident by our P3b and P3a component findings. These results indicate a significant change in early, middle-latency and late ERP components at the frontal, centro-parietal, and parieto-occipital regions of interest in response to target and distracter stimuli as a result of rTMS treatment. Overall, our preliminary results show that rTMS may prove to be an important research tool or treatment modality in addressing the stimulus hypersensitivity characteristic of autism spectrum disorders.

Electrophysiological analysis of pathways connecting the medial preoptic area with the mesencephalic central grey matter in rats.

PubMed

MacLeod, N K; Mayer, M L

1980-01-01

1. An electrophysiological study of ascending and descending connexions between the dorsal raphe region of the mesencephalic periaqueductal grey matter and the medial preoptic area has been performed in dioestrous female rats anaesthetized with urethane. 2. Extracellular action potentials recorded from 208 neurones in the medial preoptic area were analysed for a change in excitability following stimulation of the periaqueductal grey matter. 174 neurones were also tested for changes in excitability following stimulation of the mediobasal hypothalamus. 3. Stimulation of the periaqueductal grey matter at 1 Hz was rarely effective, but short trains of pulses (three at 100 Hz) usually caused an initial inhibition (62.5% of 208) of both projection identified and adjacent neurones of the medial preoptic area, at latencies of 5--90 msec (mean 34.1 +/- 1.4 msec). Inhibition following stimulation of the mediobasal hypothalamus occurred less frequently (34%) and at shorter latency (mean 12.0 +/- 1.8 msec; n = 48). 4. Less frequently (10.6%) periaqueductal grey matter stimulation caused an initial excitation of preoptic neurones at latencies of 15--180 msec, (mean 35.3 +/- 7.2). Initial excitation following mediobasal hypothalamus stimulation was stronger, occurred more frequently (29%) and at shorter latencies (range 3--60 msec, mean 13.1 +/- 1.5). Following such initial excitation, inhibition of spontaneous or ionophoretically evoked activity occurred more frequently following mediobasal hypothalamic stimulation, than after periaqueductal grey matter stimulation. 5. Twenty-four neurones displayed antidromic invasion following periaqueductal grey matter stimulation. Latencies for invasion ranged from 13 to 50 msec (mean 25.5 +/- 2.0 msec) and are suggestive of an unmyelinated projection. Occasionally an abrupt decrease in latency followed an increase in stimulus intensity. Antidromic invasion from mediobasal hypothalamus was characterized by a shorter latency (mean 12.5 +/- 0.7 msec; n = 43). A period of reduced excitability lasting 40--100 msec followed antidromic invasion from either site. 6. Antidromic responses to paired mediobasal hypothalamic or periaqueductal grey matter stimuli at 5 msec intervals revealed an increased latency of invasion of the second response, due to the partial refractory period of the neurone. Five cells showed a decreased latency of invasion at stimulus separations of 10--150 msec, interpreted as evidence of a supranormal period. Changes in conduction velocity during the supranormal period may give rise to a variable latency of invasion of spontaneously active cells. 7. These results provide evidence for direct, reciprocal connexions between the midbrain central grey and the medial preoptic area. These circuits may play a role in controlling neuroendocrine and behavioural aspects of reproductive functions.

Identification of a novel dynamic red blindness in human by event-related brain potentials.

PubMed

Zhang, Jiahua; Kong, Weijia; Yang, Zhongle

2010-12-01

Dynamic color is an important carrier that takes information in some special occupations. However, up to the present, there are no available and objective tests to evaluate dynamic color processing. To investigate the characteristics of dynamic color processing, we adopted two patterns of visual stimulus called "onset-offset" which reflected static color stimuli and "sustained moving" without abrupt mode which reflected dynamic color stimuli to evoke event-related brain potentials (ERPs) in primary color amblyopia patients (abnormal group) and subjects with normal color recognition ability (normal group). ERPs were recorded by Neuroscan system. The results showed that in the normal group, ERPs in response to the dynamic red stimulus showed frontal positive amplitudes with a latency of about 180 ms, a negative peak at about 240 ms and a peak latency of the late positive potential (LPP) in a time window between 290 and 580 ms. In the abnormal group, ERPs in response to the dynamic red stimulus were fully lost and characterized by vanished amplitudes between 0 and 800 ms. No significant difference was noted in ERPs in response to the dynamic green and blue stimulus between the two groups (P>0.05). ERPs of the two groups in response to the static red, green and blue stimulus were not much different, showing a transient negative peak at about 170 ms and a peak latency of LPP in a time window between 350 and 650 ms. Our results first revealed that some subjects who were not identified as color blindness under static color recognition could not completely apperceive a sort of dynamic red stimulus by ERPs, which was called "dynamic red blindness". Furthermore, these results also indicated that low-frequency ERPs induced by "sustained moving" may be a good and new method to test dynamic color perception competence.

The impact of micronutrient supplementation in alcohol-exposed pregnancies on information processing skills in Ukrainian infants.

PubMed

Kable, J A; Coles, C D; Keen, C L; Uriu-Adams, J Y; Jones, K L; Yevtushok, L; Kulikovsky, Y; Wertelecki, W; Pedersen, T L; Chambers, C D

2015-11-01

The potential of micronutrients to ameliorate the impact of prenatal alcohol exposure (PAE) was explored in a clinical trial conducted in Ukraine. Cardiac orienting responses (ORs) during a habituation/dishabituation learning paradigm were obtained from 6 to 12 month-olds to assess neurophysiological encoding and memory. Women who differed in prenatal alcohol use were recruited during pregnancy and assigned to a group (No study-provided supplements, multivitamin/mineral supplement, or multivitamin/mineral supplement plus choline supplement). Heart rate was collected for 30 s prior to stimulus onset and 12 s post-stimulus onset. Difference values (∆HR) for the first 3 trials of each condition were aggregated for analysis. Gestational blood samples were collected to assess maternal nutritional status and changes as a function of the intervention. Choline supplementation resulted in a greater ∆HR on the visual habituation trials for all infants and for the infants with no PAE on the dishabituation trials. The latency of the response was reduced in both conditions for all infants whose mothers received choline supplementation. Change in gestational choline level was positively related to ∆HR during habituation trials and levels of one choline metabolite, dimethylglycine (DMG), predicted ∆HR during habituation trials and latency of responses. A trend was found between DMG and ∆HR on the dishabituation trials and latency of the response. Supplementation did not affect ORs to auditory stimuli. Choline supplementation when administered together with routinely recommended multivitamin/mineral prenatal supplements during pregnancy may provide a beneficial impact to basic learning mechanisms involved in encoding and memory of environmental events in alcohol-exposed pregnancies as well as non- or low alcohol-exposed pregnancies. Changes in maternal nutrient status suggested that one mechanism by which choline supplementation may positively impact brain development is through prevention of fetal alcohol-related depletion of DMG, a metabolic nutrient that can protect against overproduction of glycine, during critical periods of neurogenesis. Copyright © 2015 Elsevier Inc. All rights reserved.

Variables associated with detection probability, detection latency, and behavioral responses of Golden-winged Warblers (Vermivora chrysoptera)

USGS Publications Warehouse

Aldinger, Kyle R.; Wood, Petra B.

2015-01-01

Detection probability during point counts and its associated variables are important considerations for bird population monitoring and have implications for conservation planning by influencing population estimates. During 2008–2009, we evaluated variables hypothesized to be associated with detection probability, detection latency, and behavioral responses of male Golden-winged Warblers in pastures in the Monongahela National Forest, West Virginia, USA. This is the first study of male Golden-winged Warbler detection probability, detection latency, or behavioral response based on point-count sampling with known territory locations and identities for all males. During 3-min passive point counts, detection probability decreased as distance to a male's territory and time since sunrise increased. During 3-min point counts with playback, detection probability decreased as distance to a male's territory increased, but remained constant as time since sunrise increased. Detection probability was greater when point counts included type 2 compared with type 1 song playback, particularly during the first 2 min of type 2 song playback. Golden-winged Warblers primarily use type 1 songs (often zee bee bee bee with a higher-pitched first note) in intersexual contexts and type 2 songs (strident, rapid stutter ending with a lower-pitched buzzy note) in intrasexual contexts. Distance to a male's territory, ordinal date, and song playback type were associated with the type of behavioral response to song playback. Overall, ~2 min of type 2 song playback may increase the efficacy of point counts for monitoring populations of Golden-winged Warblers by increasing the conspicuousness of males for visual identification and offsetting the consequences of surveying later in the morning. Because playback may interfere with the ability to detect distant males, it is important to follow playback with a period of passive listening. Our results indicate that even in relatively open pasture vegetation, detection probability of male Golden-winged Warblers is imperfect and highly variable.

A quantitative survey of gravity receptor function in mutant mouse strains.

PubMed

Jones, Sherri M; Johnson, Kenneth R; Yu, Heping; Erway, Lawrence C; Alagramam, Kumar N; Pollak, Natasha; Jones, Timothy A

2005-12-01

The purpose of this research was to identify vestibular deficits in mice using linear vestibular evoked potentials (VsEPs). VsEP thresholds, peak latencies, and peak amplitudes from 24 strains with known genetic mutations and 6 inbred background strains were analyzed and descriptive statistics generated for each strain. Response parameters from mutant homozygotes were compared with heterozygote and/or background controls and all strain averages were contrasted to normative ranges. Homozygotes of the following recessive mutations had absent VsEPs at the ages tested: Espn(je), Atp2b2dfw-2J, Spnb4qv-lnd2J, Spnb4qv-3J, Myo7ash1, Tmie(sr), Myo6sv, jc, Pcdh15av-J, Pcdh15av-2J, Pcdh15av-3J, Cdh23v-2J, Sans(js), hr, Kcne1pkr and Pou3f4del. These results suggest profound gravity receptor deficits for these homozygotes, which is consistent with the structural deficits that have been documented for many of these strains. Homozygotes of Catna2cdf, Grid2ho4J, Wnt1sw, qk, and Mbpshi strains and heterozygotes of Grid2lc had measurable VsEPs but one or more response parameters differed from the respective control group (heterozygote or background strain) or were outside normal ranges. For example, qk and Mbpshi homozygotes showed significantly prolonged latencies consistent with the abnormal myelin that has been described for these strains. Prolonged latencies may suggest deficits in neural conduction; elevated thresholds suggest reduced sensitivity, and reduced amplitudes may be suggestive for reduced neural synchrony. One mutation, Otx1jv, had all VsEP response parameters within normal limits--an expected finding because the abnormality in Otxljv is presumably restricted to the lateral semicircular canal. Interestingly, some heterozygote groups also showed abnormalities in one or more VsEP response parameters, suggesting that vestibular dysfunction, although less severe, may be present in some heterozygous animals.

Experience-dependent enhancement of pitch-specific responses in the auditory cortex is limited to acceleration rates in normal voice range

PubMed Central

Krishnan, Ananthanarayan; Gandour, Jackson T.; Suresh, Chandan H.

2015-01-01

The aim of this study is to determine how pitch acceleration rates within and outside the normal pitch range may influence latency and amplitude of cortical pitch-specific responses (CPR) as a function of language experience (Chinese, English). Responses were elicited from a set of four pitch stimuli chosen to represent a range of acceleration rates (two each inside and outside the normal voice range) imposed on the high rising Mandarin Tone 2. Pitch-relevant neural activity, as reflected in the latency and amplitude of scalp-recorded CPR components, varied depending on language-experience and pitch acceleration of dynamic, time-varying pitch contours. Peak latencies of CPR components were shorter in the Chinese than the English group across stimuli. Chinese participants showed greater amplitude than English for CPR components at both frontocentral and temporal electrode sites in response to pitch contours with acceleration rates inside the normal voice pitch range as compared to pitch contours with acceleration rates that exceed the normal range. As indexed by CPR amplitude at the temporal sites, a rightward asymmetry was observed for the Chinese group only. Only over the right temporal site was amplitude greater in the Chinese group relative to the English. These findings may suggest that the neural mechanism(s) underlying processing of pitch in the right auditory cortex reflect experience-dependent modulation of sensitivity to acceleration in just those rising pitch contours that fall within the bounds of one’s native language. More broadly, enhancement of native pitch stimuli and stronger rightward asymmetry of CPR components in the Chinese group is consistent with the notion that long-term experience shapes adaptive, distributed hierarchical pitch processing in the auditory cortex, and reflects an interaction with higher-order, extrasensory processes beyond the sensory memory trace. PMID:26166727

Methodology for Calculating Latency of GPS Probe Data

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

Wang, Zhongxiang; Hamedi, Masoud; Young, Stanley

Crowdsourced GPS probe data, such as travel time on changeable-message signs and incident detection, have been gaining popularity in recent years as a source for real-time traffic information to driver operations and transportation systems management and operations. Efforts have been made to evaluate the quality of such data from different perspectives. Although such crowdsourced data are already in widespread use in many states, particularly the high traffic areas on the Eastern seaboard, concerns about latency - the time between traffic being perturbed as a result of an incident and reflection of the disturbance in the outsourced data feed - havemore » escalated in importance. Latency is critical for the accuracy of real-time operations, emergency response, and traveler information systems. This paper offers a methodology for measuring probe data latency regarding a selected reference source. Although Bluetooth reidentification data are used as the reference source, the methodology can be applied to any other ground truth data source of choice. The core of the methodology is an algorithm for maximum pattern matching that works with three fitness objectives. To test the methodology, sample field reference data were collected on multiple freeway segments for a 2-week period by using portable Bluetooth sensors as ground truth. Equivalent GPS probe data were obtained from a private vendor, and their latency was evaluated. Latency at different times of the day, impact of road segmentation scheme on latency, and sensitivity of the latency to both speed-slowdown and recovery-from-slowdown episodes are also discussed.« less

Laterodorsal nucleus of the thalamus: A processor of somatosensory inputs.

PubMed

Bezdudnaya, Tatiana; Keller, Asaf

2008-04-20

The laterodorsal (LD) nucleus of the thalamus has been considered a "higher order" nucleus that provides inputs to limbic cortical areas. Although its functions are largely unknown, it is often considered to be involved in spatial learning and memory. Here we provide evidence that LD is part of a hitherto unknown pathway for processing somatosensory information. Juxtacellular and extracellular recordings from LD neurons reveal that they respond to vibrissa stimulation with short latency (median = 7 ms) and large magnitude responses (median = 1.2 spikes/stimulus). Most neurons (62%) had large receptive fields, responding to six and more individual vibrissae. Electrical stimulation of the trigeminal nucleus interpolaris (SpVi) evoked short latency responses (median = 3.8 ms) in vibrissa-responsive LD neurons. Labeling produced by anterograde and retrograde neuroanatomical tracers confirmed that LD neurons receive direct inputs from SpVi. Electrophysiological and neuroanatomical analyses revealed also that LD projects upon the cingulate and retrosplenial cortex, but has only sparse projections to the barrel cortex. These findings suggest that LD is part of a novel processing stream involved in spatial orientation and learning related to somatosensory cues. (c) 2008 Wiley-Liss, Inc.

Two Distinct Types of Hypercontractile Esophagus: Classic and Spastic Jackhammer

PubMed Central

Hong, Yun Soo; Min, Yang Won; Rhee, Poong-Lyul

2016-01-01

Hypercontractile esophagus (nicknamed jackhammer esophagus) is a recently defined disease within the esophageal motility disorders classification. Responses to treatments for jackhammer esophagus have been inconsistent in previous trials, possibly due to its heterogeneous manifestation. Thus, we reviewed 10 patients diagnosed with jackhammer esophagus and compared their clinical and manometric features at baseline. Additionally, manometric and symptomatic responses after treatment with known smooth muscle relaxants, including anticholinergic drugs (cimetropium bromide and scopolamine butylbromide) and a phosphodiesterase-5 inhibitor (sildenafil) were compared. We observed two distinct subgroups in the findings: one with hypercontractility and normal distal latencies (“classic jackhammer esophagus,” n=7) and the other with hypercontractility and short distal latencies (“spastic jackhammer esophagus,” n=3). The two types also differed in their responses to medications in that symptoms improved upon treatment with an anticholinergic agent in classic jackhammer esophagus patients, while spastic jackhammer esophagus was unresponsive to both the anticholinergic drugs and the phosphodiesterase-5 inhibitor. In conclusion, hypercontractile esophagus may be a heterogeneous disease with different underlying pathophysiologies. We introduced two novel terms, “classic jackhammer esophagus” and “spastic jackhammer esophagus,” to distinguish the two types. PMID:27458179

Sex-dependent effects of restraint on nociception and pituitary-adrenal hormones in the rat.

PubMed

Aloisi, A M; Steenbergen, H L; van de Poll, N E; Farabollini, F

1994-05-01

The sex-dependent effects of acute restraint (RT) on nociceptive and pituitary-adrenal responses were investigated in the rat. In a first experiment, the effect of 30 min RT on pain sensitivity was evaluated through repeated use of the tail withdrawal test during and after treatment. RT induced an increase in the nociceptive threshold, i.e., analgesia, in males and females, but the duration and time-course of this effect varied between sexes. The latencies returned to approximately control values in females in the second half of RT, but in males they remained higher for the whole period of RT and immediately afterwards. Twenty-four hours later, males displayed longer latencies than controls in response to simple reexposure to the environment. In a second experiment, ACTH and corticosterone plasma levels were measured immediately after 15 or 30 min of RT. ACTH and corticosterone were higher in restrained animals than in controls after both periods of treatment, and in both sexes; however, females showed higher basal and stress corticosterone levels than males. The role played by corticosteroids in the nociceptive responses of the two sexes is discussed.

Independence of Early Speech Processing from Word Meaning

PubMed Central

Travis, Katherine E.; Leonard, Matthew K.; Chan, Alexander M.; Torres, Christina; Sizemore, Marisa L.; Qu, Zhe; Eskandar, Emad; Dale, Anders M.; Elman, Jeffrey L.; Cash, Sydney S.; Halgren, Eric

2013-01-01

We combined magnetoencephalography (MEG) with magnetic resonance imaging and electrocorticography to separate in anatomy and latency 2 fundamental stages underlying speech comprehension. The first acoustic-phonetic stage is selective for words relative to control stimuli individually matched on acoustic properties. It begins ∼60 ms after stimulus onset and is localized to middle superior temporal cortex. It was replicated in another experiment, but is strongly dissociated from the response to tones in the same subjects. Within the same task, semantic priming of the same words by a related picture modulates cortical processing in a broader network, but this does not begin until ∼217 ms. The earlier onset of acoustic-phonetic processing compared with lexico-semantic modulation was significant in each individual subject. The MEG source estimates were confirmed with intracranial local field potential and high gamma power responses acquired in 2 additional subjects performing the same task. These recordings further identified sites within superior temporal cortex that responded only to the acoustic-phonetic contrast at short latencies, or the lexico-semantic at long. The independence of the early acoustic-phonetic response from semantic context suggests a limited role for lexical feedback in early speech perception. PMID:22875868

Nasal Immunization Confers High Avidity Neutralizing Antibody Response and Immunity to Primary and Recurrent Genital Herpes in Guinea Pigs

PubMed Central

Persson, Josefine; Zhang, Yuan; Olafsdottir, Thorunn A.; Thörn, Karolina; Cairns, Tina M.; Wegmann, Frank; Sattentau, Quentin J.; Eisenberg, Roselyn J.; Cohen, Gary H.; Harandi, Ali M.

2016-01-01

Genital herpes is one of the most prevalent sexually transmitted infections in both the developing and developed world. Following infection, individuals experience life-long latency associated with sporadic ulcerative outbreaks. Despite many efforts, no vaccine has yet been licensed for human use. Herein, we demonstrated that nasal immunization with an adjuvanted HSV-2 gD envelope protein mounts significant protection to primary infection as well as the establishment of latency and recurrent genital herpes in guinea pigs. Nasal immunization was shown to elicit specific T cell proliferative and IFN-γ responses as well as systemic and vaginal gD-specific IgG antibody (Ab) responses. Furthermore, systemic IgG Abs displayed potent HSV-2 neutralizing properties and high avidity. By employing a competitive surface plasmon resonance (SPR) analysis combined with a battery of known gD-specific neutralizing monoclonal Abs (MAbs), we showed that nasal immunization generated IgG Abs directed to two major discontinuous neutralizing epitopes of gD. These results highlight the potential of nasal immunization with an adjuvanted HSV-2 envelope protein for induction of protective immunity to primary and recurrent genital herpes. PMID:28082979

Nasal Immunization Confers High Avidity Neutralizing Antibody Response and Immunity to Primary and Recurrent Genital Herpes in Guinea Pigs.

PubMed

Persson, Josefine; Zhang, Yuan; Olafsdottir, Thorunn A; Thörn, Karolina; Cairns, Tina M; Wegmann, Frank; Sattentau, Quentin J; Eisenberg, Roselyn J; Cohen, Gary H; Harandi, Ali M

2016-01-01

Genital herpes is one of the most prevalent sexually transmitted infections in both the developing and developed world. Following infection, individuals experience life-long latency associated with sporadic ulcerative outbreaks. Despite many efforts, no vaccine has yet been licensed for human use. Herein, we demonstrated that nasal immunization with an adjuvanted HSV-2 gD envelope protein mounts significant protection to primary infection as well as the establishment of latency and recurrent genital herpes in guinea pigs. Nasal immunization was shown to elicit specific T cell proliferative and IFN-γ responses as well as systemic and vaginal gD-specific IgG antibody (Ab) responses. Furthermore, systemic IgG Abs displayed potent HSV-2 neutralizing properties and high avidity. By employing a competitive surface plasmon resonance (SPR) analysis combined with a battery of known gD-specific neutralizing monoclonal Abs (MAbs), we showed that nasal immunization generated IgG Abs directed to two major discontinuous neutralizing epitopes of gD. These results highlight the potential of nasal immunization with an adjuvanted HSV-2 envelope protein for induction of protective immunity to primary and recurrent genital herpes.

Multiple Component Event-Related Potential (mcERP) Estimation

NASA Technical Reports Server (NTRS)

Knuth, K. H.; Clanton, S. T.; Shah, A. S.; Truccolo, W. A.; Ding, M.; Bressler, S. L.; Trejo, L. J.; Schroeder, C. E.; Clancy, Daniel (Technical Monitor)

2002-01-01

We show how model-based estimation of the neural sources responsible for transient neuroelectric signals can be improved by the analysis of single trial data. Previously, we showed that a multiple component event-related potential (mcERP) algorithm can extract the responses of individual sources from recordings of a mixture of multiple, possibly interacting, neural ensembles. McERP also estimated single-trial amplitudes and onset latencies, thus allowing more accurate estimation of ongoing neural activity during an experimental trial. The mcERP algorithm is related to informax independent component analysis (ICA); however, the underlying signal model is more physiologically realistic in that a component is modeled as a stereotypic waveshape varying both in amplitude and onset latency from trial to trial. The result is a model that reflects quantities of interest to the neuroscientist. Here we demonstrate that the mcERP algorithm provides more accurate results than more traditional methods such as factor analysis and the more recent ICA. Whereas factor analysis assumes the sources are orthogonal and ICA assumes the sources are statistically independent, the mcERP algorithm makes no such assumptions thus allowing investigators to examine interactions among components by estimating the properties of single-trial responses.

Multiple pathways carry signals from short-wavelength-sensitive ('blue') cones to the middle temporal area of the macaque.

PubMed

Jayakumar, Jaikishan; Roy, Sujata; Dreher, Bogdan; Martin, Paul R; Vidyasagar, Trichur R

2013-01-01

We recorded spike activity of single neurones in the middle temporal visual cortical area (MT or V5) of anaesthetised macaque monkeys. We used flashing, stationary spatially circumscribed, cone-isolating and luminance-modulated stimuli of uniform fields to assess the effects of signals originating from the long-, medium- or short- (S) wavelength-sensitive cone classes. Nearly half (41/86) of the tested MT neurones responded reliably to S-cone-isolating stimuli. Response amplitude in the majority of the neurones tested further (19/28) was significantly reduced, though not always completely abolished, during reversible inactivation of visuotopically corresponding regions of the ipsilateral primary visual cortex (striate cortex, area V1). Thus, the present data indicate that signals originating in S-cones reach area MT, either via V1 or via a pathway that does not go through area V1. We did not find a significant difference between the mean latencies of spike responses of MT neurones to signals that bypass V1 and those that do not; the considerable overlap we observed precludes the use of spike-response latency as a criterion to define the routes through which the signals reach MT.

Automatic response activation in sequential affective priming: an ERP study

PubMed Central

Leuthold, Hartmut; Rothermund, Klaus; Schweinberger, Stefan R.

2012-01-01

Affective priming effects denote faster responses when two successively presented affective stimuli match in valence than when they mismatch. Two mechanisms have been proposed for their explanation: (i) Priming of affective information within a semantic network or distributed memory system (semantic priming). (ii) Automatic activation of the evaluative response through the affective prime (response priming). In this experiment, we sought more direct evidence for prime-induced response activations with measurement of the lateralized readiness potential (LRP). Onset of the stimulus-locked LRP was earlier in affectively congruent trials than in incongruent trials. In addition, priming modulated the LRP-amplitude of slow responses, indicating greater activation of the incorrect response hand in affectively incongruent trials. Onset of the response-locked LRP and peak latency of the P300 component were not modulated by priming but the amplitude of the N400 component was. In combination, these results suggest that both, semantic priming and response priming constitute affective priming effects in the evaluative categorization task. PMID:21642351

Long-latency reflexes account for limb biomechanics through several supraspinal pathways

PubMed Central

Kurtzer, Isaac L.

2015-01-01

Accurate control of body posture is enforced by a multitude of corrective actions operating over a range of time scales. The earliest correction is the short-latency reflex (SLR) which occurs between 20–45 ms following a sudden displacement of the limb and is generated entirely by spinal circuits. In contrast, voluntary reactions are generated by a highly distributed network but at a significantly longer delay after stimulus onset (greater than 100 ms). Between these two epochs is the long-latency reflex (LLR) (around 50–100 ms) which acts more rapidly than voluntary reactions but shares some supraspinal pathways and functional capabilities. In particular, the LLR accounts for the arm’s biomechanical properties rather than only responding to local muscle stretch like the SLR. This paper will review how the LLR accounts for the arm’s biomechanical properties and the supraspinal pathways supporting this ability. Relevant experimental paradigms include clinical studies, non-invasive brain stimulation, neural recordings in monkeys, and human behavioral studies. The sum of this effort indicates that primary motor cortex and reticular formation (RF) contribute to the LLR either by generating or scaling its structured response appropriate for the arm’s biomechanics whereas the cerebellum scales the magnitude of the feedback response. Additional putative pathways are discussed as well as potential research lines. PMID:25688187

Age-Related Changes in Accommodative Dynamics from Preschool to Adulthood

PubMed Central

Glasser, Adrian; Manny, Ruth E.; Stuebing, Karla K.

2010-01-01

Purpose. To study variations in dynamic measures of accommodation and disaccommodation with age in subjects ranging from preschool to adulthood. Methods. Accommodative responses to a step stimulus cartoon movie alternating from distance to near were recorded with a dynamic infrared photorefractor. Subjects viewed at least three stimulus cycles of far and near for four near stimulus demands (2, 3, 4, and 5 D). Latencies, peak velocities, and the magnitude of accommodative microfluctuations were calculated from the responses and compared in 41 subjects from 3 to 38 years of age. Results. Mean accommodative and disaccommodative latencies decreased linearly with age. The magnitude of accommodative microfluctuations during sustained near accommodation had a significant quadratic relationship to age, with subjects in the first decade of life having the largest fluctuations and subjects in the third decade of life having the smallest for all stimulus demands. Accommodative peak velocities were fastest in subjects in the first two decades of life, compared with subjects in the third and fourth decades; however, disaccommodative peak velocities showed no significant age differences. Conclusions. Age-related changes in dynamics occur in accommodative and disaccommodative latencies, accommodative peak velocities, and accommodative microfluctuations, all of which decrease with increasing age from preschool to adulthood. Disaccommodative peak velocities showed no change with age. PMID:19684002

How understanding immunology contributes to managing CMV disease in immunosuppressed patients: now and in future.

PubMed

Sissons, J G Patrick; Wills, Mark R

2015-06-01

Several decades of research on human cytomegalovirus (HCMV) and the principal mammalian cytomegaloviruses which to varying degrees act as models of HCMV infection, particularly murine, guinea pig and rhesus CMV, have led to the recognition of the CMVs as interesting models of persistent infection with a large and complex DNA virus, which have been highly informative of the immunology and molecular pathogenesis of the virus-host relationship in the normal host. However, it is appropriate to ask how this relative wealth of knowledge has influenced the understanding and management of clinical disease due to HCMV. This article considers the immunology of cytomegalovirus in the normal human host, and the interrelated issue of the sites of HCMV latency and mechanisms of reactivation in the myeloid cell lineage, and in related in vitro model systems. The way in which this site of latency conditions the immune response, and emerging information on the special features of the adaptive immune response to HCMV during latency are also considered. Examples of HCMV disease associated with acquired immunosuppression, principally in the context of transplantation, but also as a consequence of HIV/AIDS and immune reconstitution inflammatory syndrome, are then discussed, with a particular emphasis on how understanding the immunology of persistent infection may contribute to managing CMV disease now and in future.

Enhancing picture naming with transcranial magnetic stimulation.

PubMed

Mottaghy, Felix M; Sparing, Roland; Töpper, Rudolf

2006-01-01

The enhancement of cognitive function in healthy subjects by medication, training or intervention yields increasing political, social and ethical attention. In this paper facilitatory effects of single-pulse TMS and repetitive TMS on a simple picture naming task are presented. A significant shortening of picture naming latencies was observed after single-pulse TMS over Wernicke's area. The accuracy of the response was not affected by this speed effect. After TMS over the dominant motor cortex or over the non-dominant temporal lobe, however, no facilitation of picture naming was observed. In the rTMS experiments only rTMS of Wernicke's area had an impact on picture naming latencies resulting in a shortening of naming latencies without affecting the accuracy of the response. rTMS over the visual cortex, Broca's area or over the corresponding sites in the non-dominant hemisphere had no effect. Single-pulse TMS is able to facilitate lexical processes due to a general preactivation of language-related neuronal networks when delivered over Wernicke's area. Repetitive transcranial magnetic stimulation over Wernicke's area also leads to a brief facilitation of picture naming possibly by shortening linguistic processing time. Whether TMS or rTMS can be used to aid linguistic therapy in the rehabilitation phase of aphasic patients should be subject of further investigations.

[The influence of click polarity and stimulation rate on the auditory evoked response in relation to age].

PubMed

Tarantino, V; Stura, M; Raspino, M; Conrad, E; Porcu, A

1989-01-01

In order to study the changes which occur in phase of the click stimulus and its relation to the stimulus repetition rate on the auditory brainstem response (ABR) as a function of age, the Authors recorded the ABR from the scalp's surface of 10 newborns and 40 infants, 3 months, 6 months, 1 year and 3 years old as well as from 10 normal adults. The stimulus was a square wave of 0.1 msec duration and 90 dBHL level. The stimulus equipment was calibrated twice under visual inspection to ensure that the C and R clicks resulted in an initial membrane deflection toward and from the ear drum respectively. No significant differences could be found for the latencies and amplitude in the C-R comparison. However, the mean values of the complete group of test subjects showed most intraindividual stability for the conventional click stimulation. The latency of the ABR with excitation of the cochlea seemed to be mainly determined by the internal oscillation sequence in the cochlea and not by the stimulus polarity. The amplitudes and latencies of the ABR components tend to decrease when the stimulus rate increases and the age decreases. The importance of the stimulus characteristics is discussed and some suggestions for clinical use of ABR are made.

Virtual Morris task responses in individuals in an abstinence phase from alcohol.

PubMed

Ceccanti, Mauro; Coriale, Giovanna; Hamilton, Derek A; Carito, Valentina; Coccurello, Roberto; Scalese, Bruna; Ciafrè, Stefania; Codazzo, Claudia; Messina, Marisa Patrizia; Chaldakov, George N; Fiore, Marco

2018-02-01

The present study was aimed at examining spatial learning and memory, in 33 men and 12 women with alcohol use disorder (AUD) undergoing ethanol detoxification, by using a virtual Morris task. As controls, we recruited 29 men and 10 women among episodic drinkers without a history of alcohol addiction or alcohol-related diseases. Elevated latency to the first movement in all trials was observed only in AUD persons; furthermore, control women had longer latencies compared with control men. Increased time spent to reach the hidden platform in the learning phase was found for women of both groups compared with men, in particular during trial 3. As predicted, AUD persons (more evident in men) spent less time in the target quadrant during the probe trial; however, AUD women had longer latencies to reach the platform in the visible condition during trials 6 and 7 that resulted in a greater distance moved. As for the probe trial, men of both groups showed increased virtual locomotion compared with the women of both groups. The present investigation confirms and extends previous studies showing (i) different gender responses in spatial learning tasks, (ii) some alterations due to alcohol addiction in virtual spatial learning, and (iii) differences between AUD men and AUD women in spatial-behaviour-related paradigms.

Emotionality of Colors: An Implicit Link between Red and Dominance.

PubMed

Mentzel, Stijn V; Schücker, Linda; Hagemann, Norbert; Strauss, Bernd

2017-01-01

The color red has been shown to alter emotions, physiology, psychology, and behavior. Research has suggested that these alterations could possibly be due to a link between red and perceived dominance. In this study we examined if the color red is implicitly associated to the concept of dominance. In addition, we similarly hypothesized that blue is implicitly linked to rest. A modified Stroop word evaluation task was used in which 30 participants (23.07 ± 4.42 years) were asked to classify words shown in either red, blue, or gray (control condition), as being either dominant- or rest-related. The responses were recorded and analyzed for latency time and accuracy. The results revealed a significant word type × color interaction effect for both latency times, F (2,56) = 5.09, p = 0.009, [Formula: see text] = 0.15, and accuracy, F (1.614,45.193) = 8.57, p = 0.001, [Formula: see text] = 0.23. On average participants showed significantly shorter latency times and made less errors when categorizing dominance words shown in red, compared to blue and gray. The measured effects show strong evidence for an implicit red-dominance association and a partial red-rest disassociation. It is discussed that this association can possibly affect emotionality, with the presentation of red eliciting a dominant emotional and behavioral response.

Effects of microgravity on vestibular ontogeny: direct physiological and anatomical measurements following space flight (STS-29)

NASA Technical Reports Server (NTRS)

Jones, T. A.; Fermin, C.; Hester, P. Y.; Vellinger, J.

1993-01-01

Does space flight change gravity receptor development? The present study measured vestibular form and function in birds flown as embryos for 5 days in earth orbit (STS-29). No major changes in vestibular gross morphology were found. Vestibular response mean amplitudes and latencies were unaffected by space flight. However, the results of measuring vestibular thresholds were mixed and abnormal responses in 3 of the 8 flight animals raise important questions.

Neurophysiological correlates of altered response inhibition in internet gaming disorder and obsessive-compulsive disorder: Perspectives from impulsivity and compulsivity

PubMed Central

Kim, Minah; Lee, Tak Hyung; Choi, Jung-Seok; Kwak, Yoo Bin; Hwang, Wu Jeong; Kim, Taekwan; Lee, Ji Yoon; Lim, Jae-A; Park, Minkyung; Kim, Yeon Jin; Kim, Sung Nyun; Kim, Dai Jin; Kwon, Jun Soo

2017-01-01

Although internet gaming disorder (IGD) and obsessive-compulsive disorder (OCD) represent opposite ends of the impulsivity and compulsivity dimensions, the two disorders share common neurocognitive deficits in response inhibition. However, the similarities and differences in neurophysiological features of altered response inhibition between IGD and OCD have not been investigated sufficiently. In total, 27 patients with IGD, 24 patients with OCD, and 26 healthy control (HC) subjects participated in a Go/NoGo task with electroencephalographic recordings. N2-P3 complexes elicited during Go and NoGo condition were analyzed separately and compared among conditions and groups. NoGo-N2 latency at the central electrode site was delayed in IGD group versus the HC group and correlated positively with the severity of internet game addiction and impulsivity. NoGo-N2 amplitude at the frontal electrode site was smaller in OCD patients than in IGD patients. These findings suggest that prolonged NoGo-N2 latency may serve as a marker of trait impulsivity in IGD and reduced NoGo-N2 amplitude may be a differential neurophysiological feature between OCD from IGD with regard to compulsivity. We report the first differential neurophysiological correlate of the altered response inhibition in IGD and OCD, which may be a candidate biomarker for impulsivity and compulsivity. PMID:28134318

Functional modeling of the human auditory brainstem response to broadband stimulationa)

PubMed Central

Verhulst, Sarah; Bharadwaj, Hari M.; Mehraei, Golbarg; Shera, Christopher A.; Shinn-Cunningham, Barbara G.

2015-01-01

Population responses such as the auditory brainstem response (ABR) are commonly used for hearing screening, but the relationship between single-unit physiology and scalp-recorded population responses are not well understood. Computational models that integrate physiologically realistic models of single-unit auditory-nerve (AN), cochlear nucleus (CN) and inferior colliculus (IC) cells with models of broadband peripheral excitation can be used to simulate ABRs and thereby link detailed knowledge of animal physiology to human applications. Existing functional ABR models fail to capture the empirically observed 1.2–2 ms ABR wave-V latency-vs-intensity decrease that is thought to arise from level-dependent changes in cochlear excitation and firing synchrony across different tonotopic sections. This paper proposes an approach where level-dependent cochlear excitation patterns, which reflect human cochlear filter tuning parameters, drive AN fibers to yield realistic level-dependent properties of the ABR wave-V. The number of free model parameters is minimal, producing a model in which various sources of hearing-impairment can easily be simulated on an individualized and frequency-dependent basis. The model fits latency-vs-intensity functions observed in human ABRs and otoacoustic emissions while maintaining rate-level and threshold characteristics of single-unit AN fibers. The simulations help to reveal which tonotopic regions dominate ABR waveform peaks at different stimulus intensities. PMID:26428802

Different Cortical Dynamics in Face and Body Perception: An MEG study

PubMed Central

Meeren, Hanneke K. M.; de Gelder, Beatrice; Ahlfors, Seppo P.; Hämäläinen, Matti S.; Hadjikhani, Nouchine

2013-01-01

Evidence from functional neuroimaging indicates that visual perception of human faces and bodies is carried out by distributed networks of face and body-sensitive areas in the occipito-temporal cortex. However, the dynamics of activity in these areas, needed to understand their respective functional roles, are still largely unknown. We monitored brain activity with millisecond time resolution by recording magnetoencephalographic (MEG) responses while participants viewed photographs of faces, bodies, and control stimuli. The cortical activity underlying the evoked responses was estimated with anatomically-constrained noise-normalised minimum-norm estimate and statistically analysed with spatiotemporal cluster analysis. Our findings point to distinct spatiotemporal organization of the neural systems for face and body perception. Face-selective cortical currents were found at early latencies (120–200 ms) in a widespread occipito-temporal network including the ventral temporal cortex (VTC). In contrast, early body-related responses were confined to the lateral occipito-temporal cortex (LOTC). These were followed by strong sustained body-selective responses in the orbitofrontal cortex from 200–700 ms, and in the lateral temporal cortex and VTC after 500 ms latency. Our data suggest that the VTC region has a key role in the early processing of faces, but not of bodies. Instead, the LOTC, which includes the extra-striate body area (EBA), appears the dominant area for early body perception, whereas the VTC contributes to late and post-perceptual processing. PMID:24039712

I scan, therefore I decline: The time course of difficulty monitoring in humans (homo sapiens) and macaques (macaca mulatta).

PubMed

Smith, J David; Boomer, Joseph; Church, Barbara A; Zakrzewski, Alexandria C; Beran, Michael J; Baum, Michael L

2018-05-01

The study of nonhumans' metacognitive judgments about trial difficulty has grown into an important comparative literature. However, the potential for associative-learning confounds in this area has left room for behaviorist interpretations that are strongly asserted and hotly debated. This article considers how researchers may be able to observe animals' strategic cognitive processes more clearly by creating temporally extended problems within which associative cues are not always immediately available. We asked humans and rhesus macaques to commit to completing spatially extended mazes or to decline completing them through a trial-decline response. The mazes could sometimes be completed successfully, but other times had a constriction that blocked completion. A deliberate, systematic scanning process could preevaluate a maze and determine the appropriate response. Latency analyses charted the time course of the evaluative process. Both humans and macaques appeared, from the pattern of their latencies, to scan the mazes through before committing to completing them. Thus monkeys, too, can base trial-decline responses on temporally extended evaluation processes, confirming that those responses have strategic cognitive-processing bases in addition to behavioral-reactive bases. The results also show the value of temporally and spatially extended problems to let researchers study the trajectory of animals' online cognitive processes. (PsycINFO Database Record (c) 2018 APA, all rights reserved).

The effect of height and BMI on computer dynamic posturography parameters in women.

PubMed

Olchowik, Grażyna; Tomaszewski, Marek; Olejarz, Piotr; Warchoł, Jan; Różańska-Boczula, Monika

2014-01-01

The human body's posture control is a complex system of organs and mechanisms which controls the body's centre of gravity (COG) over its base of support (BOS). Computerised Dynamic Posturography (CDP) allows for the quantitative and objective assessment of the sensory and motor components of the body's posture control system as well as of the integration and adaptation mechanisms in the central nervous system. The aim of this study was to assess the relationships between the body's height and BMI on CDP results in a group of young healthy women without any clinical symptoms of balance disorders. It was found that the MS depended significantly on the height and BMI of the subjects as well as on the SOT conditions. As the height and BMI increased the MS value decreased. The postural response latency (LC) in the MCT statistically significantly depended only on height and showed a positive correlation. The postural response latency increased with height. The postural response amplitude for both right and left lower limbs significantly depended on height and BMI, but only for the backward movement of the platform. The response amplitude for all platform translations under all MCT conditions increased with height and BMI. The body's resultant imbalance caused by the platform perturbations in the ADT was greater in shorter people and those with a lower BMI.

The Binaural Interaction Component in Barn Owl (Tyto alba) Presents few Differences to Mammalian Data.

PubMed

Palanca-Castan, Nicolas; Laumen, Geneviève; Reed, Darrin; Köppl, Christine

2016-12-01

The auditory brainstem response (ABR) is an evoked potential that reflects the responses to sound by brainstem neural centers. The binaural interaction component (BIC) is obtained by subtracting the sum of the monaural ABR responses from the binaural response. Its latency and amplitude change in response to variations in binaural cues. The BIC is thus thought to reflect the activity of binaural nuclei and is used to non-invasively test binaural processing. However, any conclusions are limited by a lack of knowledge of the relevant processes at the level of individual neurons. The aim of this study was to characterize the ABR and BIC in the barn owl, an animal where the ITD-processing neural circuits are known in great detail. We recorded ABR responses to chirps and to 1 and 4 kHz tones from anesthetized barn owls. General characteristics of the barn owl ABR were similar to those observed in other bird species. The most prominent peak of the BIC was associated with nucleus laminaris and is thus likely to reflect the known processes of ITD computation in this nucleus. However, the properties of the BIC were very similar to previously published mammalian data and did not reveal any specific diagnostic features. For example, the polarity of the BIC was negative, which indicates a smaller response to binaural stimulation than predicted by the sum of monaural responses. This is contrary to previous predictions for an excitatory-excitatory system such as nucleus laminaris. Similarly, the change in BIC latency with varying ITD was not distinguishable from mammalian data. Contrary to previous predictions, this behavior appears unrelated to the known underlying neural delay-line circuitry. In conclusion, the generation of the BIC is currently inadequately understood and common assumptions about the BIC need to be reconsidered when interpreting such measurements.

Axonal Conduction Delays, Brain State, and Corticogeniculate Communication.

PubMed

Stoelzel, Carl R; Bereshpolova, Yulia; Alonso, Jose-Manuel; Swadlow, Harvey A

2017-06-28

Thalamocortical conduction times are short, but layer 6 corticothalamic axons display an enormous range of conduction times, some exceeding 40-50 ms. Here, we investigate (1) how axonal conduction times of corticogeniculate (CG) neurons are related to the visual information conveyed to the thalamus, and (2) how alert versus nonalert awake brain states affect visual processing across the spectrum of CG conduction times. In awake female Dutch-Belted rabbits, we found 58% of CG neurons to be visually responsive, and 42% to be unresponsive. All responsive CG neurons had simple, orientation-selective receptive fields, and generated sustained responses to stationary stimuli. CG axonal conduction times were strongly related to modulated firing rates (F1 values) generated by drifting grating stimuli, and their associated interspike interval distributions, suggesting a continuum of visual responsiveness spanning the spectrum of axonal conduction times. CG conduction times were also significantly related to visual response latency, contrast sensitivity (C-50 values), directional selectivity, and optimal stimulus velocity. Increasing alertness did not cause visually unresponsive CG neurons to become responsive and did not change the response linearity (F1/F0 ratios) of visually responsive CG neurons. However, for visually responsive CG neurons, increased alertness nearly doubled the modulated response amplitude to optimal visual stimulation (F1 values), significantly shortened response latency, and dramatically increased response reliability. These effects of alertness were uniform across the broad spectrum of CG axonal conduction times. SIGNIFICANCE STATEMENT Corticothalamic neurons of layer 6 send a dense feedback projection to thalamic nuclei that provide input to sensory neocortex. While sensory information reaches the cortex after brief thalamocortical axonal delays, corticothalamic axons can exhibit conduction delays of <2 ms to 40-50 ms. Here, in the corticogeniculate visual system of awake rabbits, we investigate the functional significance of this axonal diversity, and the effects of shifting alert/nonalert brain states on corticogeniculate processing. We show that axonal conduction times are strongly related to multiple visual response properties, suggesting a continuum of visual responsiveness spanning the spectrum of corticogeniculate axonal conduction times. We also show that transitions between awake brain states powerfully affect corticogeniculate processing, in some ways more strongly than in layer 4. Copyright © 2017 the authors 0270-6474/17/376342-17$15.00/0.

Preoperative characteristics of auditory brainstem response in acoustic neuroma with useful hearing: importance as a preliminary investigation for intraoperative monitoring.

PubMed

Aihara, Noritaka; Murakami, Shingo; Takahashi, Mariko; Yamada, Kazuo

2014-01-01

We classified the results of preoperative auditory brainstem response (ABR) in 121 patients with useful hearing and considered the utility of preoperative ABR as a preliminary assessment for intraoperative monitoring. Wave V was confirmed in 113 patients and was not confirmed in 8 patients. Intraoperative ABR could not detect wave V in these 8 patients. The 8 patients without wave V were classified into two groups (flat and wave I only), and the reason why wave V could not be detected may have differed between the groups. Because high-frequency hearing was impaired in flat patients, an alternative to click stimulation may be more effective. Monitoring cochlear nerve action potential (CNAP) may be useful because CNAP could be detected in 4 of 5 wave I only patients. Useful hearing was preserved after surgery in 1 patient in the flat group and 2 patients in wave I only group. Among patients with wave V, the mean interaural latency difference of wave V was 0.88 ms in Class A (n = 57) and 1.26 ms in Class B (n = 56). Because the latency of wave V is already prolonged before surgery, to estimate delay in wave V latency during surgery probably underestimates cochlear nerve damage. Recording intraoperative ABR is indispensable to avoid cochlear nerve damage and to provide information for surgical decisions. Confirming the condition of ABR before surgery helps to solve certain problems, such as choosing to monitor the interaural latency difference of wave V, CNAP, or alternative sound-evoked ABR.

Relationship between selected orientation rest frame, circular vection and space motion sickness

NASA Technical Reports Server (NTRS)

Harm, D. L.; Parker, D. E.; Reschke, M. F.; Skinner, N. C.

1998-01-01

Space motion sickness (SMS) and spatial orientation and motion perception disturbances occur in 70-80% of astronauts. People select "rest frames" to create the subjective sense of spatial orientation. In microgravity, the astronaut's rest frame may be based on visual scene polarity cues and on the internal head and body z axis (vertical body axis). The data reported here address the following question: Can an astronaut's orientation rest frame be related and described by other variables including circular vection response latencies and space motion sickness? The astronaut's microgravity spatial orientation rest frames were determined from inflight and postflight verbal reports. Circular vection responses were elicited by rotating a virtual room continuously at 35 degrees/s in pitch, roll and yaw with respect to the astronaut. Latency to the onset of vection was recorded from the time the crew member opened their eyes to the onset of vection. The astronauts who used visual cues exhibited significantly shorter vection latencies than those who used internal z axis cues. A negative binomial regression model was used to represent the observed total SMS symptom scores for each subject for each flight day. Orientation reference type had a significant effect, resulting in an estimated three-fold increase in the expected motion sickness score on flight day 1 for astronauts who used visual cues. The results demonstrate meaningful classification of astronauts' rest frames and their relationships to sensitivity to circular vection and SMS. Thus, it may be possible to use vection latencies to predict SMS severity and duration.

Separating neural and vascular effects of caffeine using simultaneous EEG–FMRI: Differential effects of caffeine on cognitive and sensorimotor brain responses

PubMed Central

Diukova, Ana; Ware, Jennifer; Smith, Jessica E.; Evans, C. John; Murphy, Kevin; Rogers, Peter J.; Wise, Richard G.

2012-01-01

The effects of caffeine are mediated through its non-selective antagonistic effects on adenosine A1 and A2A adenosine receptors resulting in increased neuronal activity but also vasoconstriction in the brain. Caffeine, therefore, can modify BOLD FMRI signal responses through both its neural and its vascular effects depending on receptor distributions in different brain regions. In this study we aim to distinguish neural and vascular influences of a single dose of caffeine in measurements of task-related brain activity using simultaneous EEG–FMRI. We chose to compare low-level visual and motor (paced finger tapping) tasks with a cognitive (auditory oddball) task, with the expectation that caffeine would differentially affect brain responses in relation to these tasks. To avoid the influence of chronic caffeine intake, we examined the effect of 250 mg of oral caffeine on 14 non and infrequent caffeine consumers in a double-blind placebo-controlled cross-over study. Our results show that the task-related BOLD signal change in visual and primary motor cortex was significantly reduced by caffeine, while the amplitude and latency of visual evoked potentials over occipital cortex remained unaltered. However, during the auditory oddball task (target versus non-target stimuli) caffeine significantly increased the BOLD signal in frontal cortex. Correspondingly, there was also a significant effect of caffeine in reducing the target evoked response potential (P300) latency in the oddball task and this was associated with a positive potential over frontal cortex. Behavioural data showed that caffeine also improved performance in the oddball task with a significantly reduced number of missed responses. Our results are consistent with earlier studies demonstrating altered flow-metabolism coupling after caffeine administration in the context of our observation of a generalised caffeine-induced reduction in cerebral blood flow demonstrated by arterial spin labelling (19% reduction over grey matter). We were able to identify vascular effects and hence altered neurovascular coupling through the alteration of low-level task FMRI responses in the face of a preserved visual evoked potential. However, our data also suggest a cognitive effect of caffeine through its positive effect on the frontal BOLD signal consistent with the shortening of oddball EEG response latency. The combined use of EEG–FMRI is a promising methodology for investigating alterations in brain function in drug and disease studies where neurovascular coupling may be altered on a regional basis. PMID:22561357

The effects of click and tone-burst stimulus parameters on the vestibular evoked myogenic potential (VEMP).

PubMed

Akin, Faith Wurm; Murnane, Owen D; Proffitt, Tina M

2003-11-01

Vestibular evoked myogenic potentials (VEMP) are short latency electromyograms (EMG) evoked by high-level acoustic stimuli and recorded from surface electrodes over the tonically contracted sternocleidomastoid (SCM) muscle and are presumed to originate in the saccule. The present experiments examined the effects of click and tone-burst level and stimulus frequency on the latency, amplitude, and threshold of the VEMP in subjects with normal hearing sensitivity and no history of vestibular disease. VEMPs were recorded in all subjects using 100 dB nHL click stimuli. Most subjects had VEMPs present at 500, 750, and 1000 Hz, and few subjects had VEMPs present at 2000 Hz. The response amplitude of the VEMP increased with click and tone-burst level, whereas VEMP latency was not influenced by the stimulus level. The largest tone-burst-evoked VEMPs and lowest thresholds were obtained at 500 and 750 Hz. VEMP latency was independent of stimulus frequency when tone-burst duration was held constant.

Pathogenesis of cranial neuropathies in Moebius syndrome: Electrodiagnostic orofacial studies.

PubMed

Renault, Francis; Flores-Guevara, Roberto; Sergent, Bernard; Baudon, Jean Jacques; Aouizerate, Jessie; Vazquez, Marie-Paule; Gitiaux, Cyril

2018-02-09

We designed a retrospective study of 59 patients with congenital sporadic nonprogressive bilateral facial and abducens palsies. Examinations included needle electromyography (EMG) of facial and oral muscles, facial nerve motor latency and conduction velocity (FNCV), and blink responses (BR). Neurogenic EMG changes were found in 1 or more muscles in 55 of 59 patients, with no abnormal spontaneous activity. EMG changes were homogeneously neurogenic in 17 patients, homogeneously myopathic in 1 patient, and heterogeneous in 41 of 59 patients. Motor latency was increased according to recordings from 52 of 137 facial muscles. An increase of motor latency was not associated with neurogenic EMG (Fischer's test: right, P = 1; left, P = 0.76). FNCV was slowed in 19 of 36 patients. BR was absent bilaterally in 35 of 58 patients; when present, R1 and R2 latencies were normal. Our results support the hypothesis of an early developmental defect localized in motor cranial nerves with spared V-VII internuclear pathways. Muscle Nerve, 2018. © 2018 Wiley Periodicals, Inc.

Cooling modifies mixed median and ulnar palmar studies in carpal tunnel syndrome.

PubMed

Araújo, Rogério Gayer Machado de; Kouyoumdjian, João Aris

2007-09-01

Temperature is an important and common variable that modifies nerve conduction study parameters in practice. Here we compare the effect of cooling on the mixed palmar median to ulnar negative peak-latency difference (PMU) in electrodiagnosis of carpal tunnel syndrome (CTS). Controls were 22 subjects (19 women, mean age 42.1 years, 44 hands). Patients were diagnosed with mild symptomatic CTS (25 women, mean age 46.6 years, 34 hands). PMU was obtained at the usual temperature, >32 degrees C, and after wrist/hand cooling to <27 degrees C in ice water. After cooling, there was a significantly greater increase in PMU and mixed ulnar palmar latency in patients versus controls. We concluded that cooling significantly modifies the PMU. We propose that the latencies of compressed nerve overreact to cooling and that this response could be a useful tool for incipient CTS electrodiagnosis. There was a significant latency overreaction of the ulnar nerve to cooling in CTS patients. We hypothesize that subclinical ulnar nerve compression is associated with CTS.

Weak Responses to Auditory Feedback Perturbation during Articulation in Persons Who Stutter: Evidence for Abnormal Auditory-Motor Transformation

PubMed Central

Cai, Shanqing; Beal, Deryk S.; Ghosh, Satrajit S.; Tiede, Mark K.; Guenther, Frank H.; Perkell, Joseph S.

2012-01-01

Previous empirical observations have led researchers to propose that auditory feedback (the auditory perception of self-produced sounds when speaking) functions abnormally in the speech motor systems of persons who stutter (PWS). Researchers have theorized that an important neural basis of stuttering is the aberrant integration of auditory information into incipient speech motor commands. Because of the circumstantial support for these hypotheses and the differences and contradictions between them, there is a need for carefully designed experiments that directly examine auditory-motor integration during speech production in PWS. In the current study, we used real-time manipulation of auditory feedback to directly investigate whether the speech motor system of PWS utilizes auditory feedback abnormally during articulation and to characterize potential deficits of this auditory-motor integration. Twenty-one PWS and 18 fluent control participants were recruited. Using a short-latency formant-perturbation system, we examined participants’ compensatory responses to unanticipated perturbation of auditory feedback of the first formant frequency during the production of the monophthong [ε]. The PWS showed compensatory responses that were qualitatively similar to the controls’ and had close-to-normal latencies (∼150 ms), but the magnitudes of their responses were substantially and significantly smaller than those of the control participants (by 47% on average, p<0.05). Measurements of auditory acuity indicate that the weaker-than-normal compensatory responses in PWS were not attributable to a deficit in low-level auditory processing. These findings are consistent with the hypothesis that stuttering is associated with functional defects in the inverse models responsible for the transformation from the domain of auditory targets and auditory error information into the domain of speech motor commands. PMID:22911857

Eliminating medullary 5-HT neurons delays arousal and decreases the respiratory response to repeated episodes of hypoxia in neonatal rat pups

PubMed Central

Schneider, Robert W.; Tobia, Christine M.; Commons, Kathryn G.

2015-01-01

Arousal from sleep is a critical defense mechanism when infants are exposed to hypoxia, and an arousal deficit has been postulated as contributing to the etiology of the sudden infant death syndrome (SIDS). The brainstems of SIDS infants are deficient in serotonin (5-HT) and tryptophan hydroxylase (TPH) and have decreased binding to 5-HT receptors. This study explores a possible connection between medullary 5-HT neuronal activity and arousal from sleep in response to hypoxia. Medullary raphe 5-HT neurons were eliminated from neonatal rat pups with intracisterna magna (CM) injections of 5,7-dihydroxytryptamine (DHT) at P2-P3. Each pup was then exposed to four episodes of hypoxia during sleep at three developmental ages (P5, P15, and P25) to produce an arousal response. Arousal, heart rate, and respiratory rate responses of DHT-injected pups were compared with pups that received CM artificial cerebrospinal fluid (aCSF) and those that received DHT but did not have a significant reduction in medullary 5-HT neurons. During each hypoxia exposure, the time to arousal from the onset of hypoxia (latency) was measured together with continuous measurements of heart and respiratory rates, oxyhemoglobin saturation, and chamber oxygen concentration. DHT-injected pups with significant losses of medullary 5-HT neurons exhibited significantly longer arousal latencies and decreased respiratory rate responses to hypoxia compared with controls. These results support the hypothesis that in newborn and young rat pups, 5-HT neurons located in the medullary raphe contribute to the arousal response to hypoxia. Thus alterations medullary 5-HT mechanisms might contribute to an arousal deficit and contribute to death in SIDS infants. PMID:26702023

Shades of grey; Assessing the contribution of the magno- and parvocellular systems to neural processing of the retinal input in the human visual system from the influence of neural population size and its discharge activity on the VEP.

PubMed

Marcar, Valentine L; Baselgia, Silvana; Lüthi-Eisenegger, Barbara; Jäncke, Lutz

2018-03-01

Retinal input processing in the human visual system involves a phasic and tonic neural response. We investigated the role of the magno- and parvocellular systems by comparing the influence of the active neural population size and its discharge activity on the amplitude and latency of four VEP components. We recorded the scalp electric potential of 20 human volunteers viewing a series of dartboard images presented as a pattern reversing and pattern on-/offset stimulus. These patterns were designed to vary both neural population size coding the temporal- and spatial luminance contrast property and the discharge activity of the population involved in a systematic manner. When the VEP amplitude reflected the size of the neural population coding the temporal luminance contrast property of the image, the influence of luminance contrast followed the contrast response function of the parvocellular system. When the VEP amplitude reflected the size of the neural population responding to the spatial luminance contrast property the image, the influence of luminance contrast followed the contrast response function of the magnocellular system. The latencies of the VEP components examined exhibited the same behavior across our stimulus series. This investigation demonstrates the complex interplay of the magno- and parvocellular systems on the neural response as captured by the VEP. It also demonstrates a linear relationship between stimulus property, neural response, and the VEP and reveals the importance of feedback projections in modulating the ongoing neural response. In doing so, it corroborates the conclusions of our previous study.

Short-latency afferent inhibition is a poor predictor of individual susceptibility to rTMS-induced plasticity in the motor cortex of young and older adults.

PubMed

Young-Bernier, Marielle; Tanguay, Annick N; Davidson, Patrick S R; Tremblay, François

2014-01-01

Cortical plasticity, including long-term potentiation (LTP)-like plasticity, can be assessed non-invasively with repetitive transcranial magnetic stimulation (rTMS) protocols. In this study, we examined age differences in responses to intermittent theta burst stimulation (iTBS) in a group of 20 young and 18 healthy older adults. Because the cholinergic system plays a role in the neural processes underlying learning and memory, including LTP, we also investigated whether short latency afferent inhibition (SAI), a neurophysiological marker of central cholinergic activity, would be associated with age-related differences in LTP-like plasticity induced by iTBS. SAI was first assessed by examining the modulation of motor evoked potentials (MEPs) in response to median nerve conditioning 20 ms prior to TMS. Participants then underwent iTBS (3 pulses at 50 Hz every 200 ms for 2 s with 8 s between trains, repeated 20 times). MEP responses (120% resting motor threshold (RMT)) were assessed immediately after iTBS and 5, 10, and 20 min post-application. Responses to iTBS were quite variable in both age groups, with only approximately 60% of the participants (n = 13 young and 10 older adults) showing the expected facilitation of MEP responses. There were no significant age group differences in MEP facilitation following iTBS. Although older adults exhibited reduced SAI, individual variations were not associated with susceptibility to express LTP-like induced plasticity after iTBS. Overall, these results are consistent with reports of high inter-individual variability in responses to iTBS. Although SAI was reduced in older adults, consistent with a deterioration of the cholinergic system with age, SAI levels were not associated with LTP-like plasticity as assessed with iTBS.

Short-latency afferent inhibition is a poor predictor of individual susceptibility to rTMS-induced plasticity in the motor cortex of young and older adults

PubMed Central

Young-Bernier, Marielle; Tanguay, Annick N.; Davidson, Patrick S. R.; Tremblay, François

2014-01-01

Cortical plasticity, including long-term potentiation (LTP)-like plasticity, can be assessed non-invasively with repetitive transcranial magnetic stimulation (rTMS) protocols. In this study, we examined age differences in responses to intermittent theta burst stimulation (iTBS) in a group of 20 young and 18 healthy older adults. Because the cholinergic system plays a role in the neural processes underlying learning and memory, including LTP, we also investigated whether short latency afferent inhibition (SAI), a neurophysiological marker of central cholinergic activity, would be associated with age-related differences in LTP-like plasticity induced by iTBS. Methods: SAI was first assessed by examining the modulation of motor evoked potentials (MEPs) in response to median nerve conditioning 20 ms prior to TMS. Participants then underwent iTBS (3 pulses at 50 Hz every 200 ms for 2 s with 8 s between trains, repeated 20 times). MEP responses (120% resting motor threshold (RMT)) were assessed immediately after iTBS and 5, 10, and 20 min post-application. Results: Responses to iTBS were quite variable in both age groups, with only approximately 60% of the participants (n = 13 young and 10 older adults) showing the expected facilitation of MEP responses. There were no significant age group differences in MEP facilitation following iTBS. Although older adults exhibited reduced SAI, individual variations were not associated with susceptibility to express LTP-like induced plasticity after iTBS. Conclusion: Overall, these results are consistent with reports of high inter-individual variability in responses to iTBS. Although SAI was reduced in older adults, consistent with a deterioration of the cholinergic system with age, SAI levels were not associated with LTP-like plasticity as assessed with iTBS. PMID:25147523

The 170ms Response to Faces as Measured by MEG (M170) Is Consistently Altered in Congenital Prosopagnosia

PubMed Central

Carbon, Claus-Christian; Deffke, Iris; Sander, Tilmann; Grüter, Thomas; Grüter, Martina; Trahms, Lutz; Curio, Gabriel

2015-01-01

Modularity of face processing is still a controversial issue. Congenital prosopagnosia (cPA), a selective and lifelong impairment in familiar face recognition without evidence of an acquired cerebral lesion, offers a unique opportunity to support this fundamental hypothesis. However, in spite of the pronounced behavioural impairment, identification of a functionally relevant neural alteration in congenital prosopagnosia by electrophysiogical methods has not been achieved so far. Here we show that persons with congenital prosopagnosia can be distinguished as a group from unimpaired persons using magnetoencephalography. Early face-selective MEG-responses in the range of 140 to 200ms (the M170) showed prolonged latency and decreased amplitude whereas responses to another category (houses) were indistinguishable between subjects with congenital prosopagnosia and unimpaired controls. Latency and amplitude of face-selective EEG responses (the N170) which were simultaneously recorded were statistically indistinguishable between subjects with cPA and healthy controls which resolves heterogeneous and partly conflicting results from existing studies. The complementary analysis of categorical differences (evoked activity to faces minus evoked activity to houses) revealed that the early part of the 170ms response to faces is altered in subjects with cPA. This finding can be adequately explained in a common framework of holistic and part-based face processing. Whereas a significant brain-behaviour correlation of face recognition performance and the size of the M170 amplitude is found in controls a corresponding correlation is not seen in subjects with cPA. This indicates functional relevance of the alteration found for the 170ms response to faces in cPA and pinpoints the impairment of face processing to early perceptual stages. PMID:26393348

Bilateral force transients in the upper limbs evoked by single-pulse microstimulation in the pontomedullary reticular formation.

PubMed

Hirschauer, Thomas J; Buford, John A

2015-04-01

Neurons in the pontomedullary reticular formation (PMRF) give rise to the reticulospinal tract. The motor output of the PMRF was investigated using stimulus-triggered averaging of electromyography (EMG) and force recordings in two monkeys (M. fascicularis). EMG was recorded from 12 pairs of upper limb muscles, and forces were detected using two isometric force-sensitive handles. Of 150 stimulation sites, 105 (70.0%) produced significant force responses, and 139 (92.5%) produced significant EMG responses. Based on the average flexor EMG onset latency of 8.3 ms and average force onset latency of 15.9 ms poststimulation, an electromechanical delay of ∼7.6 ms was calculated. The magnitude of force responses (∼10 mN) was correlated with the average change in EMG activity (P < 0.001). A multivariate linear regression analysis was used to estimate the contribution of each muscle to force generation, with flexors and extensors exhibiting antagonistic effects. A predominant force output pattern of ipsilateral flexion and contralateral extension was observed in response to PMRF stimulation, with 65.3% of significant ipsilateral force responses directed medially and posteriorly (P < 0.001) and 78.6% of contralateral responses directed laterally and anteriorly (P < 0.001). This novel approach permits direct measurement of force outputs evoked by central nervous system microstimulation. Despite the small magnitude of poststimulus EMG effects, low-intensity single-pulse microstimulation of the PMRF evoked detectable forces. The forces, showing the combined effect of all muscle activity in the arms, are consistent with reciprocal pattern of force outputs from the PMRF detectable with stimulus-triggered averaging of EMG. Copyright © 2015 the American Physiological Society.

Hearing with Two Ears: Evidence for Cortical Binaural Interaction during Auditory Processing.

PubMed

Henkin, Yael; Yaar-Soffer, Yifat; Givon, Lihi; Hildesheimer, Minka

2015-04-01

Integration of information presented to the two ears has been shown to manifest in binaural interaction components (BICs) that occur along the ascending auditory pathways. In humans, BICs have been studied predominantly at the brainstem and thalamocortical levels; however, understanding of higher cortically driven mechanisms of binaural hearing is limited. To explore whether BICs are evident in auditory event-related potentials (AERPs) during the advanced perceptual and postperceptual stages of cortical processing. The AERPs N1, P3, and a late negative component (LNC) were recorded from multiple site electrodes while participants performed an oddball discrimination task that consisted of natural speech syllables (/ka/ vs. /ta/) that differed by place-of-articulation. Participants were instructed to respond to the target stimulus (/ta/) while performing the task in three listening conditions: monaural right, monaural left, and binaural. Fifteen (21-32 yr) young adults (6 females) with normal hearing sensitivity. By subtracting the response to target stimuli elicited in the binaural condition from the sum of responses elicited in the monaural right and left conditions, the BIC waveform was derived and the latencies and amplitudes of the components were measured. The maximal interaction was calculated by dividing BIC amplitude by the summed right and left response amplitudes. In addition, the latencies and amplitudes of the AERPs to target stimuli elicited in the monaural right, monaural left, and binaural listening conditions were measured and subjected to analysis of variance with repeated measures testing the effect of listening condition and laterality. Three consecutive BICs were identified at a mean latency of 129, 406, and 554 msec, and were labeled N1-BIC, P3-BIC, and LNC-BIC, respectively. Maximal interaction increased significantly with progression of auditory processing from perceptual to postperceptual stages and amounted to 51%, 55%, and 75% of the sum of monaural responses for N1-BIC, P3-BIC, and LNC-BIC, respectively. Binaural interaction manifested in a decrease of the binaural response compared to the sum of monaural responses. Furthermore, listening condition affected P3 latency only, whereas laterality effects manifested in enhanced N1 amplitudes at the left (T3) vs. right (T4) scalp electrode and in a greater left-right amplitude difference in the right compared to left listening condition. The current AERP data provides evidence for the occurrence of cortical BICs during perceptual and postperceptual stages, presumably reflecting ongoing integration of information presented to the two ears at the final stages of auditory processing. Increasing binaural interaction with the progression of the auditory processing sequence (N1 to LNC) may support the notion that cortical BICs reflect inherited interactions from preceding stages of upstream processing together with discrete cortical neural activity involved in binaural processing. Clinically, an objective measure of cortical binaural processing has the potential of becoming an appealing neural correlate of binaural behavioral performance. American Academy of Audiology.

Autism and Classical Eyeblink Conditioning: Performance Changes of the Conditioned Response Related to Autism Spectrum Disorder Diagnosis

PubMed Central

Welsh, John P.; Oristaglio, Jeffrey T.

2016-01-01

Changes in the timing performance of conditioned responses (CRs) acquired during trace and delay eyeblink conditioning (EBC) are presented for diagnostic subgroups of children having autism spectrum disorder (ASD) aged 6–15 years. Children diagnosed with autistic disorder (AD) were analyzed separately from children diagnosed with either Asperger’s syndrome or Pervasive developmental disorder (Asp/PDD) not otherwise specified and compared to an age- and IQ-matched group of children who were typically developing (TD). Within-subject and between-groups contrasts in CR performance on sequential exposure to trace and delay EBC were analyzed to determine whether any differences would expose underlying functional heterogeneities of the cerebral and cerebellar systems, in ASD subgroups. The EBC parameters measured were percentage CRs, CR onset latency, and CR peak latency. Neither AD nor Asp/PDD groups were impaired in CR acquisition during trace or delay EBC. Both AD and Asp/PDD altered CR timing, but not always in the same way. Although the AD group showed normal CR timing during trace EBC, the Asp/PDD group showed a significant 27 and 28 ms increase in CR onset and peak latency, respectively, during trace EBC. In contrast, the direction of the timing change was opposite during delay EBC, during which the Asp/PDD group showed a significant 29 ms decrease in CR onset latency and the AD group showed a larger 77 ms decrease in CR onset latency. Only the AD group showed a decrease in CR peak latency during delay EBC, demonstrating another difference between AD and Asp/PDD. The difference in CR onset latency during delay EBC for both AD and Asp/PDD was due to an abnormal prevalence of early onset CRs that were intermixed with CRs having normal timing, as observed both in CR onset histograms and mean CR waveforms. In conclusion, significant heterogeneity in EBC performance was apparent between diagnostic groups, and this may indicate that EBC performance can report the heterogeneity in the neurobiological predispositions for ASD. The findings will inform further explorations with larger cohorts, different sensory modalities, and different EBC paradigms and provide a reference set for future EBC studies of children having ASD and non-human models. PMID:27563293

Involvement of NMDA receptor mechanisms in jaw electromyographic activity and plasma extravasation induced by inflammatory irritant application to temporomandibular joint region of rats.

PubMed

Yu, X M; Sessle, B J; Haas, D A; Izzo, A; Vernon, H; Hu, J W

1996-11-01

The aim of this study was to examine the possible role of N-methyl-D-aspartate (NMDA) receptor mechanisms in responses induced by the small-fibre excitant and inflammatory irritant mustard oil injected into the temporomandibular joint (TMJ) region of rats. The effects of the non-competitive NMDA antagonist MK-801 were tested on the mustard oil-evoked increases in electromyographic (EMG) activity of the masseter and digastric muscles and Evans Blue plasma extravasation. Five minutes before the mustard oil injection, MK-801 or its vehicle was administered systemically (i.v.), into the third ventricle (i.c.v.), or locally into the TMJ region. Compared with control animals receiving vehicle, the rats receiving MK-801 at an i.v. dose of 0.5 mg/kg (n = 5) showed a significant reduction in the incidence and magnitude of EMG responses as well as in the plasma extravasation evoked by mustard oil; MK-801 at an i.v. dose of 0.1 mg/kg (n = 5) had no significant effect on plasma extravasation or on the incidence and magnitude of EMG responses but did significantly increase the latency of EMG responses. An i.c.v. dose of 0.1 mg/kg (n = 5) or 0.01 mg/kg (n = 5) had no significant effect on plasma extravasation or incidence of EMG responses but did significantly reduce the magnitudes of the masseter EMG response; the 0.01 mg/kg dose also significantly increased the latency of the digastric EMG response. The magnitudes of both the masseter and digastric EMG responses were also significantly reduced by MK-801 administered into the TMJ region at a dose of 0.1 mg/kg (n = 5) but not by 0.01 mg/kg (n = 5); neither dose significantly affected the incidence of EMG responses or the plasma extravasation. These data suggest that both central and peripheral NMDA receptor mechanisms may play an important role in EMG responses evoked by the small-fibre excitant and inflammatory irritant mustard oil, but that different neurochemical mechanisms may be involved in the plasma extravasation induced by mustard oil.

Two-Stage Processing of Sounds Explains Behavioral Performance Variations due to Changes in Stimulus Contrast and Selective Attention: An MEG Study

PubMed Central

Kauramäki, Jaakko; Jääskeläinen, Iiro P.; Hänninen, Jarno L.; Auranen, Toni; Nummenmaa, Aapo; Lampinen, Jouko; Sams, Mikko

2012-01-01

Selectively attending to task-relevant sounds whilst ignoring background noise is one of the most amazing feats performed by the human brain. Here, we studied the underlying neural mechanisms by recording magnetoencephalographic (MEG) responses of 14 healthy human subjects while they performed a near-threshold auditory discrimination task vs. a visual control task of similar difficulty. The auditory stimuli consisted of notch-filtered continuous noise masker sounds, and of 1020-Hz target tones occasionally () replacing 1000-Hz standard tones of 300-ms duration that were embedded at the center of the notches, the widths of which were parametrically varied. As a control for masker effects, tone-evoked responses were additionally recorded without masker sound. Selective attention to tones significantly increased the amplitude of the onset M100 response at 100 ms to the standard tones during presence of the masker sounds especially with notches narrower than the critical band. Further, attention modulated sustained response most clearly at 300–400 ms time range from sound onset, with narrower notches than in case of the M100, thus selectively reducing the masker-induced suppression of the tone-evoked response. Our results show evidence of a multiple-stage filtering mechanism of sensory input in the human auditory cortex: 1) one at early (100 ms) latencies bilaterally in posterior parts of the secondary auditory areas, and 2) adaptive filtering of attended sounds from task-irrelevant background masker at longer latency (300 ms) in more medial auditory cortical regions, predominantly in the left hemisphere, enhancing processing of near-threshold sounds. PMID:23071654

The validity of different measures of automatic alcohol action tendencies.

PubMed

Kersbergen, Inge; Woud, Marcella L; Field, Matt

2015-03-01

Previous studies have demonstrated that automatic alcohol action tendencies are related to alcohol consumption and hazardous drinking. These action tendencies are measured with reaction time tasks in which the latency to make an approach response to alcohol pictures is compared with the latency to make an avoidance response. In the literature, 4 different tasks have been used, and these tasks differ on whether alcohol is a relevant (R) or irrelevant (IR) feature for categorization and on whether participants must make a symbolic approach response (stimulus-response compatibility [SRC] tasks) or an overt behavioral response (approach avoidance tasks [AAT]) to the pictures. Previous studies have shown positive correlations between measures of action tendencies and hazardous drinking and weekly alcohol consumption. However, results have been inconsistent and the different measures have not been directly compared with each other. Therefore, it is unclear which task is the best predictor of hazardous drinking and alcohol consumption. In the present study, 80 participants completed all 4 measures of action tendencies (i.e., R-SRC, IR-SRC, R-AAT, and IR-AAT) and measures of alcohol consumption and hazardous drinking. Stepwise regressions showed that the R-SRC and R-AAT were the only significant predictors of hazardous drinking, whereas the R-AAT was the only reliable predictor of alcohol consumption. Our results confirm that drinking behavior is positively correlated with automatic alcohol approach tendencies, but only if alcohol-relatedness is the relevant feature for categorization. Theoretical implications and methodological issues are discussed. (PsycINFO Database Record (c) 2015 APA, all rights reserved).

Two Parallel Olfactory Pathways for Processing General Odors in a Cockroach

PubMed Central

Watanabe, Hidehiro; Nishino, Hiroshi; Mizunami, Makoto; Yokohari, Fumio

2017-01-01

In animals, sensory processing via parallel pathways, including the olfactory system, is a common design. However, the mechanisms that parallel pathways use to encode highly complex and dynamic odor signals remain unclear. In the current study, we examined the anatomical and physiological features of parallel olfactory pathways in an evolutionally basal insect, the cockroach Periplaneta americana. In this insect, the entire system for processing general odors, from olfactory sensory neurons to higher brain centers, is anatomically segregated into two parallel pathways. Two separate populations of secondary olfactory neurons, type1 and type2 projection neurons (PNs), with dendrites in distinct glomerular groups relay olfactory signals to segregated areas of higher brain centers. We conducted intracellular recordings, revealing olfactory properties and temporal patterns of both types of PNs. Generally, type1 PNs exhibit higher odor-specificities to nine tested odorants than type2 PNs. Cluster analyses revealed that odor-evoked responses were temporally complex and varied in type1 PNs, while type2 PNs exhibited phasic on-responses with either early or late latencies to an effective odor. The late responses are 30–40 ms later than the early responses. Simultaneous intracellular recordings from two different PNs revealed that a given odor activated both types of PNs with different temporal patterns, and latencies of early and late responses in type2 PNs might be precisely controlled. Our results suggest that the cockroach is equipped with two anatomically and physiologically segregated parallel olfactory pathways, which might employ different neural strategies to encode odor information. PMID:28529476

Humoral immunity in tuberculin skin test anergy and its role in high-risk persons exposed to active tuberculosis.

PubMed

Encinales, Liliana; Zuñiga, Joaquin; Granados-Montiel, Julio; Yunis, Maria; Granados, Julio; Almeciga, Ingrid; Clavijo, Olga; Awad, Carlos; Collazos, Vilma; Vargas-Rojas, María Inés; Bañales-Mendez, José Luis; Vazquez-Castañeda, Lilia; Stern, Joel N; Romero, Viviana; Fridkis-Hareli, Masha; Frindkis-Hareli, Masha; Terreros, Daniel; Fernandez-Viña, Marcelo; Yunis, Edmond J

2010-02-01

The most common test to identify latent tuberculosis is the tuberculin skin test that detects T cell responses of delayed type hypersensitivity type IV. Since it produces false negative reactions in active tuberculosis or in high-risk persons exposed to tuberculosis patients as shown in this report, we studied antibody profiles to explain the anergy of such responses in high-risk individuals without active infection. Our results showed that humoral immunity against tuberculin, regardless of the result of the tuberculin skin test is important for protection from active tuberculosis and that the presence of high antibody titers is a more reliable indicator of infection latency suggesting that latency can be based on the levels of antibodies together with in vitro proliferation of peripheral blood mononuclear cells in the presence of the purified protein derivative. Importantly, anti-tuberculin IgG antibody levels mediate the anergy described herein, which could also prevent reactivation of disease in high-risk individuals with high antibody titers. Such anti-tuberculin IgG antibodies were also found associated with blocking and/or stimulation of in vitro cultures of PBMC with tuberculin. In this regard, future studies need to establish if immune responses to Mycobacterium tuberculosis can generate a broad spectrum of reactions either toward Th1 responses favoring stimulation by cytokines or by antibodies and those toward diminished responses by Th2 cytokines or blocking by antibodies; possibly involving mechanisms of antibody dependent protection from Mtb by different subclasses of IgG. Published by Elsevier Ltd.