Sample records for brainstem evoked potentials

  1. Brainstem auditory evoked potentials in cattle sedated with xylazine

    PubMed Central

    Arai, Shozo

    2008-01-01

    This study examined the effect of sedation with xylazine on the brainstem auditory evoked potentials (BAEP) of cattle to determine whether sedation causes differences in waveform configuration, peak latencies, interpeak latencies, measurement time of the average count (2000 responses), and clinical signs. There were no significant differences between the sedation and no-sedation groups in peak latency of any stimulus intensities. In the sedation group, the baselines of waveforms were comparatively stabilized. Those in the no-sedation group were unstable, however, because the measurement can be influenced by excessive muscle movement. The present findings suggest that clinically, it is useful to use a sedative when measuring BAEP in cattle to control excessive movement of the cattle without influencing the peak latencies. PMID:18505193

  2. Air pollution is associated with brainstem auditory nuclei pathology and delayed brainstem auditory evoked potentials

    PubMed Central

    Calderón-Garcidueñas, Lilian; D’Angiulli, Amedeo; Kulesza, Randy J; Torres-Jardón, Ricardo; Osnaya, Norma; Romero, Lina; Keefe, Sheyla; Herritt, Lou; Brooks, Diane M; Avila-Ramirez, Jose; Delgado-Chávez, Ricardo; Medina-Cortina, Humberto; González-González, Luis Oscar

    2011-01-01

    We assessed brainstem inflammation in children exposed to air pollutants by comparing brainstem auditory evoked potentials (BAEPs) and blood inflammatory markers in children age 96.3± 8.5 months from highly polluted (n=34) versus a low polluted city (n=17). The brainstems of nine children with accidental deaths were also examined. Children from the highly polluted environment had significant delays in wave III (t(50)=17.038; p<0.0001) and wave V (t(50)=19.730; p<0.0001) but no delay in wave I (p=0.548). They also had significantly longer latencies than controls for interwave intervals I–III, III–V, and I–V (all t(50)> 7.501; p<0.0001), consisting with delayed central conduction time of brainstem neural transmission. Highly exposed children showed significant evidence of inflammatory markers and their auditory and vestibular nuclei accumulated ? synuclein and/or ? amyloid 1–42. Medial superior olive neurons, critically involved in BAEPs, displayed significant pathology. Children’s exposure to urban air pollution increases their risk for auditory and vestibular impairment. PMID:21458557

  3. Brainstem auditory-evoked potentials in two meditative mental states

    PubMed Central

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

    2010-01-01

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

  4. Brainstem auditory evoked potential abnormalities in vascular malformations of the posterior fossa

    Microsoft Academic Search

    U. W. Buettner; M. Stöhr; E. Koletzki

    1983-01-01

    Recent reports indicate that malformations of arteries and veins in the posterior fossa are a common cause of facial spasm and trigeminal neuralgia. More rarely they may also cause facial nerve paresis and hearing loss. When vascular malformations are present, brainstem auditory evoked potentials (BAEPs) sometimes show abnormalities similar to those usually recorded in patients with tumours in the cerebellopontine

  5. Brainstem auditory evoked potentials in experimentally-induced bovine spongiform encephalopathy

    Microsoft Academic Search

    Shozo Arai; Yoshitaka Matsui; Shigeo Fukuda; Hiroyuki Okada; Sadao Onoe

    2009-01-01

    This study was carried out to evaluate the features of neurological dysfunction in experimentally-induced bovine spongiform encephalopathy (BSE)-infected cattle using brainstem auditory evoked potentials (BAEP). The progressive prolongation of peak latency of waves III and V was observed right-and-left bilaterally at the onset of neurological symptoms. The peak latency of wave V and the I–V interpeak latency (IPL) in BSE

  6. Auditory brainstem evoked potentials peak identification by finite impulse response digital filters.

    PubMed

    Pratt, H; Urbach, D; Bleich, N

    1989-01-01

    Linear phase finite impulse response (FIR) filtering can be used to differentiate auditory brainstem evoked potentials (ABEP) components. The power spectrum of ABEP at high intensities indicates that they contain 3 frequency bands that can be distinguished by applying appropriate digital filters with the following characteristics: up to 240 Hz (revealing slow components), 240-483 Hz (resulting in medium components) and above 500 Hz (leaving only fast components). The results using these filters, indicate that the medium components coincide with peaks I, III and V and that the slow filter results in a 'pedestal' whose peak coincides with peak V. These findings were used for automatic identification of ABEP peaks. A coincidence of the 'pedestal' peak with a medium component was sought and labelled peak V. The preceding medium peaks were labelled, in order of decreasing latency, III and I. Validation of this procedure was conducted on ABEP from normal subjects, using different stimulus rates and intensities, as well as from selected neurological patients with lesions affecting the brainstem. Provided the waveform included a 'pedestal', the results proved this procedure to be reliable and in very good agreement with manual identification and measurement of ABEP peaks. PMID:2803115

  7. Brainstem auditory and somatosensory evoked potentials: a methodological study to evaluate the reproducibility of two devices.

    PubMed

    Moncho, D; Poca, M A; Minoves, T; Ferré, A; Rahnama, K; Sahuquillo, J

    2014-12-01

    We aimed to determine whether statistical significant differences exist between the sets of results obtained from two devices used in our department for measuring brainstem auditory evoked potentials (BAEPs) and somatosensory evoked potentials (SEPs). We obtained BAEP and median and posterior tibial nerve SEP values bilaterally in ten healthy subjects. The tests were performed on the same subject using two devices consecutively. The equipment consisted of a Nicolet Viking-IV (Nicolet, Madison, WI, USA) and a Viking Select (Viasys Healthcare, Madison, WI, USA), and the same recording electrodes and stimulator (auditory and electrical) were used without modifying any postural position of the subject. The stimuli and recording parameters were the same for both devices. We obtained 20 sets of data for each type of test. The Bland–Altman plots as well as the one-sample t-test or Wilcoxon signed rank test were used to compare data between the two groups of data sets. We found no significant differences between the sets of values obtained with the two devices. Our analysis indicates that the two devices are equal in recording all different variables of BAEP and SEP, which allows us to combine the BAEP and SEP data obtained from the two devices for follow-up studies involving quantitative statistical methods. This study received institutional approval (protocol number PRAG-154/2013). PMID:25420133

  8. [Intraoperative monitoring of brainstem auditory evoked potentials during microvascular decompression of cranial nerves in cerebellopontine angle].

    PubMed

    Polo, G; Fischer, C

    2009-04-01

    Brainstem auditory evoked potentials (BAEP) monitoring is a useful tool to decrease the danger of hearing loss during pontocerebellar angle surgery, particularly in microvascular decompression (MVD). Critical complications arising during MVD surgery are the stretching of the VIII nerve - the main cause of hearing loss - labyrinthine artery manipulation, direct trauma with instruments, or a nearby coagulation, and at end of the surgery neocompression of the cochlear nerve by the prosthesis positioned between the conflicting vessel(s) and the VIIth-VIIIth nerve complex. All these dangers warrant the use of BEAP monitoring during the surgical team's training period. Based on delay in latency of peak V, we established warning thresholds that can provide useful feedback to the surgeon to modify the surgical strategy: the initial signal at 0.4 ms is considered the safety limit. A second signal threshold at 0.6 ms (warning signal for risk) corresponds to the group of patients without resultant hearing loss. The third threshold characterized by the delay of peak V is at 1 ms (warning signal for a potentially critical situation). BAEP monitoring provides the surgeon with information on the functional state of the auditory pathways and should help avoid or correct manoeuvres that can harm hearing function. BAEP monitoring during VIIth-VIIIth complex surgery, particularly in MVD of facial nerves for HFS is very useful during the learning period. PMID:19298982

  9. Source estimation of auditory brainstem evoked potentials: comparison of 3CLT and dipole localization.

    PubMed

    Pratt, H; Geva, A B; Feingold, K; Zeevi, Y Y

    1995-05-01

    The generators of auditory brainstem evoked potentials (ABEPs) are generally agreed to be located between the auditory nerve and upper pons. Thus, they are all located within a few cm from the center of the head. Three-channel Lissajous' trajectory (3CLT) provides the amplitude and orientation of a centrally located equivalent dipole of surface recorded activity. Volume conductor theory predicts decreased spatial resolution of source estimation the deeper the source. In this study we compared source estimates obtained with 3CLT, using three orthogonal differential channels, with those obtained with two other source estimation methods: i) setting the generators at their known anatomical coordinates and calculating orientation and magnitude of the source (dipole localization method--DLM); ii) estimation of all source parameters, including the number of sources by wavelet-type decomposition, without assumptions on the location of the sources (multiple source estimate--MSE). 3CLT, DLM and MSE all converged on magnitudes and orientations that were not significantly different from each other, and locations that were within a few cm of each other. In conclusion, although 3CLT can only estimate a single, centrally located equivalent dipole, in the specific case of ABEPs, it provides the same information available from the more demanding source estimate methods. In addition to the considerable saving in recording channels, 3CLT is reference-independent and thus avoids ambiguities resulting from the choice of reference. PMID:7653255

  10. Association of Chronic and Current Measures of Lead Exposure with Different Components of Brainstem Auditory Evoked Potentials

    Microsoft Academic Search

    Margit L Bleecker; D Patrick Ford; Karen N Lindgren; Karin Scheetz; Michael J Tiburzi

    2003-01-01

    Current blood lead (PbB) affects brainstem auditory evoked potentials (BAEPs) in children but whether a similar association exists in lead-exposed adults remains unclear. During an investigation of the neurobehavioral effects of occupational lead exposure we performed BAEPs on 359 English- and French-speaking, currently exposed, male, lead smelter workers having a mean (S.D.) age of 41 (9.0) years, employment duration of

  11. A possible collicular component of the auditory evoked potential and its relationship to brainstem and cerebellar auditory potentials.

    PubMed

    Shaw, N A

    1992-12-01

    Auditory evoked potentials were recorded from the rat using skull screw electrodes inserted over the inferior colliculus and the cerebellum. In addition, brainstem auditory evoked potentials (BAEPs) were also recorded. The response recorded from over the inferior colliculus consisted of a slow positive potential with one of two possible peak latencies. The mean latency of the earlier potential was 5.6 ms and that of the later potential was 6.4 ms. A hypothetical generator for the first collicular potential is the termination of the lateral lemniscus in the ventrolateral inferior colliculus, while the later collicular potential could have its origins within the brachium of the inferior colliculus. None of the principal nor minor BAEP waves corresponded to either of the collicular responses. Nor did the trough of negativity between BAEP waves IV and V which is often thought to reflect activity generated within the midbrain. The potential recorded over the cerebellum also consisted of a slow positivity but with a slightly sharper contour than that of the collicular response. The mean latency of the cerebellar potential was 4.9 ms. As there was no temporal relationship between collicular and cerebellar potentials, the present study provided no support for the theory that cerebellar auditory potentials are artefactual and simply far field reflections of activity generated in the inferior colliculus. Judging by the timing of the BAEP waves, it is also concluded that the afferent volley most likely projects to the cerebellum via a collateral pathway branching off the caudal part of the lateral lemniscus. PMID:1493771

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

    PubMed Central

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

    2014-01-01

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

  13. Inhalational exposure to carbonyl sulfide produces altered brainstem auditory and somatosensory-evoked potentials in Fischer 344N rats.

    PubMed

    Herr, David W; Graff, Jaimie E; Moser, Virginia C; Crofton, Kevin M; Little, Peter B; Morgan, Daniel L; Sills, Robert C

    2007-01-01

    Carbonyl sulfide (COS), a chemical listed by the original Clean Air Act, was tested for neurotoxicity by a National Institute of Environmental Health Sciences/National Toxicology Program and U.S. Environmental Protection Agency collaborative investigation. Previous studies demonstrated that COS produced cortical and brainstem lesions and altered auditory neurophysiological responses to click stimuli. This paper reports the results of expanded neurophysiological examinations that were an integral part of the previously published experiments (Morgan et al., 2004, Toxicol. Appl. Pharmacol. 200, 131-145; Sills et al., 2004, Toxicol. Pathol. 32, 1-10). Fisher 334N rats were exposed to 0, 200, 300, or 400 ppm COS for 6 h/day, 5 days/week for 12 weeks, or to 0, 300, or 400 ppm COS for 2 weeks using whole-body inhalation chambers. After treatment, the animals were studied using neurophysiological tests to examine: peripheral nerve function, somatosensory-evoked potentials (SEPs) (tail/hindlimb and facial cortical regions), brainstem auditory-evoked responses (BAERs), and visual flash-evoked potentials (2-week study). Additionally, the animals exposed for 2 weeks were examined using a functional observational battery (FOB) and response modification audiometry (RMA). Peripheral nerve function was not altered for any exposure scenario. Likewise, amplitudes of SEPs recorded from the cerebellum were not altered by treatment with COS. In contrast, amplitudes and latencies of SEPs recorded from cortical areas were altered after 12-week exposure to 400 ppm COS. The SEP waveforms were changed to a greater extent after forelimb stimulation than tail stimulation in the 2-week study. The most consistent findings were decreased amplitudes of BAER peaks associated with brainstem regions after exposure to 400 ppm COS. Additional BAER peaks were affected after 12 weeks, compared to 2 weeks of treatment, indicating that additional regions of the brainstem were damaged with longer exposures. The changes in BAERs were observed in the absence of altered auditory responsiveness in FOB or RMA. This series of experiments demonstrates that COS produces changes in brainstem auditory and cortical somatosensory neurophysiological responses that correlate with previously described histopathological damage. PMID:17079700

  14. [A practical application of brainstem evoked response audiometry (author's transl)].

    PubMed

    Janssen, T

    1981-09-01

    After a brief review of Brainstem Evoked Response Audiometry (BERA) for clinical diagnosis of middle and inner ear hearing losses (Fig. 2, 3) and retrocochlear damages a new practical application is presented: Brainstem Evoked Response Audiometry in Tympanoplasty. Recordings of acoustically evoked brainstem potentials have been made in middle ear surgery in order to get direct objective information about the mobility of the stapes (Fig. 4) and the sound conducting mechanism of the middle ear after tympanoplasty (Fig. 5). Because of the damping factor of the middle ear after tympanoplastic reconstruction quantitative evaluation of sound transmission to the internal ear. Via brainstem potentials evoked by loudspeakers or probe tubes is difficult. Therefore, a special mechanical vibrating system for direct stimulation of the middle ear apparatus at various locations will have to be developed. PMID:7345314

  15. Human brainstem auditory-evoked potentials in deep experimental diving to pressures up to 62.5 bar.

    PubMed

    Lorenz, J; Athanassenas, G; Hampe, P; Plath, G; Wenzel, J

    1992-09-01

    The neural mechanisms underlying the high pressure neurologic syndrome (HPNS), which limit man's safe advance to extreme diving depths, are still unclear. This work was aimed at a better understanding of HPNS through study of brainstem auditory-evoked potentials (BAEP). BAEP were repeatedly recorded within 2 experimental chamber dives, Titan VIII (2 divers, maximum depth of 560 msw, compression time to bottom 109 h) and Titan XI (3 divers, maximum depth of 615 msw, compression time to bottom 240 h). Prolongation of the IV/V-complex occurred in 2 divers upon reaching 525 msw during Titan VIII compression and was accompanied by vestibular disturbances and amplitude increases of finger tremor. Both categories of changes--clinical signs and IV/V delay--gradually diminished during a 4-day stay at 545 msw, suggesting that they depended on excessive compression rates and insufficient acclimation time. Longer holding times at intermittent depths during Titan XI clearly reduced both HPNS symptoms and magnitude of prolongation of IV/V latencies. Wave I and wave III latency did not significantly change, pointing to a suppression of pontomesencephalic transmission. We infer that pressure suppresses synaptic transmission or triggers an increase of cortical or subcortical efferent inhibitory modulation of upper pontine and midbrain auditory afferents. Postdive controls revealed no persistent changes of BAEP measures in either the Titan VIII or XI divers. PMID:1355311

  16. The effect of sound level, temperature and dehydration on the brainstem auditory evoked potential in anuran amphibians.

    PubMed

    Carey, M B; Zelick, R

    1993-11-01

    Brainstem auditory evoked potentials (BAEPs) were used to examine the effects of sound level, temperature, and dehydration on the auditory pathway of three species of anuran amphibians: Rana pipiens, Bufo americanus and B. terrestris. BAEP latency, amplitude and a measure of threshold were determined for all stimulus and test conditions. Threshold values obtained with this technique were similar to other neural measures of threshold in anurans, and were stable for repeated measures within 12 h and over three days. Transient changes in temperature caused non-linear changes in BAEP threshold and latency. Above 20 degrees C small threshold shifts were elicited, while below 20 degrees C we observed rapid deterioration of threshold. Animals acclimated to a cold temperature (14 degrees C) were acoustically less sensitive than warm (21 degrees C) animals, even when both groups were tested at colder temperatures. Because peripheral components of the BAEP were most affected by both transient and acclimation (longer term) cooling and warming, the sensory epithelium appears to be the most temperature-sensitive component of the auditory pathway. Dehydrated frogs showed no auditory dysfunction until a critical level of dehydration was reached. More dehydration-resistant species (B. terrestris and B. americanus) were less susceptible to BAEP degradation near their critical dehydration level. PMID:8294266

  17. Inhalational Exposure to Carbonyl Sulfide Produces Altered Brainstem Auditory and Somatosensory-Evoked Potentials in Fischer 344N Rats

    Microsoft Academic Search

    David W. Herr; Jaimie E. Graff; Virginia C. Moser; Kevin M. Crofton; Peter B. Little; Daniel L. Morgan; Robert C. Sills

    2007-01-01

    Carbonyl sulfide (COS), a chemical listed by the original Clean Air Act, was tested for neurotoxicity by a National Institute of Environmental Health Sciences\\/National Toxicology Program and U.S. Environmental Protection Agency collaborative investiga- tion. Previous studies demonstrated that COS produced cortical and brainstem lesions and altered auditory neurophysiological responses to click stimuli. This paper reports the results of ex- panded

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

    PubMed

    Zaaroor, M; Starr, A

    1991-01-01

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

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

    PubMed

    Zaaroor, M; Starr, A

    1991-01-01

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

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

    PubMed

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

    2015-01-01

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

  1. Gap prepulse inhibition and auditory brainstem-evoked potentials as objective measures for tinnitus in guinea pigs

    PubMed Central

    Dehmel, Susanne; Eisinger, Daniel; Shore, Susan E.

    2012-01-01

    Tinnitus or ringing of the ears is a subjective phantom sensation necessitating behavioral models that objectively demonstrate the existence and quality of the tinnitus sensation. The gap detection test uses the acoustic startle response elicited by loud noise pulses and its gating or suppression by preceding sub-startling prepulses. Gaps in noise bands serve as prepulses, assuming that ongoing tinnitus masks the gap and results in impaired gap detection. This test has shown its reliability in rats, mice, and gerbils. No data exists for the guinea pig so far, although gap detection is similar across mammals and the acoustic startle response is a well-established tool in guinea pig studies of psychiatric disorders and in pharmacological studies. Here we investigated the startle behavior and prepulse inhibition (PPI) of the guinea pig and showed that guinea pigs have a reliable startle response that can be suppressed by 15 ms gaps embedded in narrow noise bands preceding the startle noise pulse. After recovery of auditory brainstem response (ABR) thresholds from a unilateral noise over-exposure centered at 7 kHz, guinea pigs showed diminished gap-induced reduction of the startle response in frequency bands between 8 and 18 kHz. This suggests the development of tinnitus in frequency regions that showed a temporary threshold shift (TTS) after noise over-exposure. Changes in discharge rate and synchrony, two neuronal correlates of tinnitus, should be reflected in altered ABR waveforms, which would be useful to objectively detect tinnitus and its localization to auditory brainstem structures. Therefore, we analyzed latencies and amplitudes of the first five ABR waves at suprathreshold sound intensities and correlated ABR abnormalities with the results of the behavioral tinnitus testing. Early ABR wave amplitudes up to N3 were increased for animals with tinnitus possibly stemming from hyperactivity and hypersynchrony underlying the tinnitus percept. Animals that did not develop tinnitus after noise exposure showed the opposite effect, a decrease in wave amplitudes for the later waves P4–P5. Changes in latencies were only observed in tinnitus animals, which showed increased latencies. Thus, tinnitus-induced changes in the discharge activity of the auditory nerve and central auditory nuclei are represented in the ABR. PMID:22666193

  2. 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…

  3. Brainstem evoked response audiometry (BAER) in neonates with hyperbilirubinemia

    Microsoft Academic Search

    Pramod Sharma; N. P. Chhangani; Kesh Ram Meena; Rakesh Jora; Navratan Sharma; B. D. Gupta

    2006-01-01

    Objective: To evaluate Brainstem Evoked Response Audiometry (BAER) as an objective testing of hearing assessment in icteric babies\\u000a and correlate the abnormalities with serum bilirubin levels.Methods: BAER recordings were taken in 30 icteric ferm neonates at birth, at peak of serum bilirubin levels and on a follw-up visit\\u000a at 2–4 months of age.Results: Mean latency of waves and interwave intervals

  4. Kcna1 gene deletion lowers the behavioral sensitivity of mice to small changes in sound location and increases asynchronous brainstem auditory evoked potentials, but does not affect hearing thresholds

    PubMed Central

    Allen, Paul D.; Ison, James R.

    2012-01-01

    Sound localization along the azimuth depends on the sensitivity of binaural nuclei in the auditory brainstem to small differences in interaural level and timing occurring within a sub-millisecond epoch, and on monaural pathways that transmit level and timing cues with high temporal fidelity to insure their coincident arrival at the binaural targets. The soma and axons of these brainstem neurons are heavily invested with ion channels containing the low-threshold potassium channel subunit Kv1.1, which previous in-vitro and in-vivo studies suggest are important for regulating their high input-output correspondence and temporal synchrony. We compared awake Kcna1 null mutant (?/?) mice lacking Kv1.1 with +/+ mice to determine if Kv1.1 activity contributes to sound localization, and examined anesthetized mice for absolute hearing thresholds for suprathreshold differences that may be revealed in the waveforms of auditory brainstem response potentials. The awake ?/? mice tested with reflex modification audiometry had reduced sensitivity to an abrupt change in the location of a broad band noise compared to +/+ mice, while anesthetized ?/? mice had normal absolute thresholds for tone pips but a high level of stimulus-evoked but asynchronous background activity. Evoked potential waveforms had progressively earlier peaks and troughs in ?/? mice but the amplitude excursions between adjacent features were identical in the two groups. Their greater excitability and asynchrony in suprathreshold evoked potentials coupled with their normal thresholds suggests that a disruption in central neural processing in ?/? mice and not peripheral hearing loss is responsible for their poor sound localization. PMID:22396426

  5. SOMATOSENSORY EVOKED POTENTIALS

    EPA Science Inventory

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

  6. Motor evoked potential polyphasia

    PubMed Central

    Chowdhury, Fahmida A.; Ceronie, Bryan; Nashef, Lina; Elwes, Robert D.C.; Richardson, Mark P.

    2015-01-01

    Objective: We compared the motor evoked potential (MEP) phases using transcranial magnetic stimulation in patients with idiopathic generalized epilepsy (IGE), their relatives, and healthy controls, hypothesizing that patients and their unaffected relatives may share a subtle pathophysiologic abnormality. Methods: In a cross-sectional study, we investigated 23 patients with IGE, 34 first-degree relatives, and 30 matched healthy controls. Transcranial magnetic stimulation was performed to produce a series of suprathreshold single-pulse MEPs. A semiautomated method was used to count phases. We compared between groups the mean number of MEP phases, the stimulus-to-stimulus variability in MEP phases, and the proportion of polyphasic MEPs within subjects. Results: Patients with IGE and their relatives had a significantly increased number of MEP phases (median for patients 2.24, relatives 2.17, controls 2.01) and a significantly higher proportion of MEPs with more than 2 phases than controls (median for patients 0.118, relatives 0.088, controls 0.013). Patients had a greater stimulus-to-stimulus variability in number of MEP phases than controls. There were no differences between patients and relatives. Conclusion: Increased MEP polyphasia in patients with IGE and their first-degree relatives may reflect transient abnormal evoked oscillations. The presence of polyphasic MEPs in relatives as well as patients suggests that MEP polyphasia is not related to treatment, and is in isolation insufficient to predispose to epilepsy. Polyphasic MEP may be a novel endophenotype in IGE. PMID:25740859

  7. SUPERIOR COLLICULUS LESIONS AND FLASH EVOKED POTENTIALS FROM RAT CORTEX

    EPA Science Inventory

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

  8. DIFFERENTIAL IMPACT OF HYPOTHERMIA AND PENTOBARBITAL ON BRAINSTEM AUDITORY EVOKED RESPONSE

    EPA Science Inventory

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

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

    E-print Network

    Reichmuth, Colleen

    The binaural click-evoked auditory brainstem response of the California sea lion (Zalophus collected from seven California sea lions in order to provide a basic description of short-latency auditory to progressively attenuated clicks were collected for three additional sea lions. Wave amplitudes decreased

  10. Sensory evoked potentials in herpes simplex encephalitis.

    PubMed

    Aguglia, U; Farnarier, G; Gambardella, A; Quattrone, A

    1991-10-01

    Flash visual potentials (FEPs), somatosensory evoked potentials (SEPs) and auditory brainstem responses (ABR) were recorded in a 66-year-old patient presenting with clinical, EEG and CT brain scan features of herpes simplex encephalitis (HSE). At the time of evoked potential study (10 days after onset of the disease) the patient was treated with iv barbiturate on controlled respiration (lidocaine and phenytoin were not utilized); core temperature was 37 degrees C and pupils were dilated and nonreactive. Cortical FEPs were not recognizable on 02 lead, whereas they were clearly evident on 01 with normal latency of early N1, P1, N2 waves and delayed P2 component. SEPs showed normal peripheral and central conduction times, but N20 peak was bilaterally absent with unrecognizable (on P3) or delayed (on P4) N33 wave. No ABR (including wave I) were found on stimulation of the right ear, whereas delayed wave V with prolonged interpeak I-V latency was found on stimulation of the left ear. In conclusion, changes in sensory evoked potentials in HSE seem to be caused either by necrotic-hemorrhagic damage (with the disappearance of some cortical responses), by coma (with alterations in middle-latency cortical responses) and by increased intracranial pressure (with subsequent ABR abnormalities). PMID:1795696

  11. Evoked potentials in chronic n-hexane intoxication

    SciTech Connect

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

    1989-07-01

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

  12. Frequency specificity of chirp-evoked auditory brainstem responses

    NASA Astrophysics Data System (ADS)

    Wegner, Oliver; Dau, Torsten

    2002-03-01

    This study examines the usefulness of the upward chirp stimulus developed by Dau et al. [J. Acoust. Soc. Am. 107, 1530-1540 (2000)] for retrieving frequency-specific information. The chirp was designed to produce simultaneous displacement maxima along the cochlear partition by compensating for frequency-dependent traveling-time differences. In the first experiment, auditory brainstem responses (ABR) elicited by the click and the broadband chirp were obtained in the presence of high-pass masking noise, with cutoff frequencies of 0.5, 1, 2, 4, and 8 kHz. Results revealed a larger wave-V amplitude for chirp than for click stimulation in all masking conditions. Wave-V amplitude for the chirp increased continuously with increasing high-pass cutoff frequency while it remains nearly constant for the click for cutoff frequencies greater than 1 kHz. The same two stimuli were tested in the presence of a notched-noise masker with one-octave wide spectral notches corresponding to the cutoff frequencies used in the first experiment. The recordings were compared with derived responses, calculated offline, from the high-pass masking conditions. No significant difference in response amplitude between click and chirp stimulation was found for the notched-noise responses as well as for the derived responses. In the second experiment, responses were obtained using narrow-band stimuli. A low-frequency chirp and a 250-Hz tone pulse with comparable duration and magnitude spectrum were used as stimuli. The narrow-band chirp elicited a larger response amplitude than the tone pulse at low and medium stimulation levels. Overall, the results of the present study further demonstrate the importance of considering peripheral processing for the formation of ABR. The chirp might be of particular interest for assessing low-frequency information.

  13. Study of evoked potentials in human African trypanosomiasis.

    PubMed

    Tabaraud, F; Hugon, J; Tapie, P; Buguet, A; Lonsdorfer, A; Gati, R; Doua, F; Dumas, M

    1992-08-01

    Human African trypanosomiasis or sleeping sickness has a stage of neurological involvement characterized by the onset of diffuse meningoencephalitis with sleep disturbances and decreased wakefulness. The pathogenesis of this disease is not well understood. We studied auditory, visual, sensory, and motor evoked potentials in 16 patients with trypanosomiasis in the early stage of meningoencephalitis. In all patients, the brain-stem auditory evoked response (BAER) and the pattern-reversal visual evoked response (PVER) were normal. On the other hand, abnormalities of the somatosensory evoked response (SSER) or the motor evoked response (MER) were found in only five cases; however, their relationship to the illness could not be definitely confirmed. The study results indicate that the evaluated pathways were essentially intact, in particular at the level of the brain-stem in the early stage of the disease. Sleep disturbances and decreased wakefulness noted at this stage were thus linked more closely to functional involvement at the level of the sleep centres than to any detectable specific anatomic lesion. PMID:1495120

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

    PubMed Central

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

    2014-01-01

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

  15. Visual evoked potentials in neurosyphilis.

    PubMed Central

    Conrad, B; Benecke, R; Müsers, H; Prange, H; Behrens-Baumann, W

    1983-01-01

    The visual evoked potential (VEP) to pattern reversal was recorded in 79 patients with neurosyphilis. Sixteen patients (20%) had abnormal VEP latencies with a predominance of pathological VEP values in the group of tabes dorsalis (50%) as compared to general paresis (18%) or meningovascular forms (13%). A comparison of the frequency of abnormal VEPs with that of other ophthalmological tests (visual acuity, visual field, central campimetry, pupillary reactions, dark adaptation, optic fundus) yielded no diagnostic superiority of VEP. PMID:6842196

  16. 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.

  17. Abnormal brainstem auditory evoked responses in mitochondrial neurogastrointestinal encephalomyopathy (MNGIE): Evidence of delayed central conduction time

    Microsoft Academic Search

    Josep Gamez; Teresa Minoves

    2006-01-01

    ObjectiveTo assess the usefulness of brain auditory evoked potentials (BAEPs) in the study of asymptomatic white matter alterations in brain MRI observed in mitochondrial neurogastrointestinal encephalomyopathy (MNGIE) patients.

  18. 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.

  19. Brainstem auditory evoked response sensitivity: comparison with other neurologic tests in the detection of retrocochlear lesions.

    PubMed

    Benitez, J T; Arsenault, M D

    1989-01-01

    Brainstem auditory evoked response (BAER) tests were obtained in 3 patients with suspected retrocochlear lesions. Subsequently, CT scans and the surgical procedure demonstrated tumors of about the same size (2 cm) in the cerebellopontine angle. One was an VIIIth-nerve schwannoma, one a meningioma, and one a VIIth-nerve neuroma. BAER recordings were analyzed with results of other tests: conventional audiometry, stapedius reflex measurements and electronystagmography (ENG). A striking finding was a normal BAER in the patient with the VIIIth-nerve schwannoma. ENG recordings in this case showed ipsilateral impairment of optokinetic nystagmus. The BAER was abnormal in the other 2 patients. A consistent abnormality for the 3 patients was absence of stapedius reflex in the ear in question. This study disclosed the advantage of utilizing a battery of tests in the investigation of retrocochlear lesions. The ENG recordings should include evaluation of the vestibulo-oculomotor pathways. PMID:2594335

  20. USE OF SENSORY EVOKED POTENTIALS IN TOXICOLOGY

    EPA Science Inventory

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

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

    E-print Network

    Dasgupta, Dipankar

    for understanding the neural transcription of speech and music, language related processing disorders, and brain plasticity at initial stages of the auditory pathway. Despite its potential clinical and empirical utility monitoring). Auditory evoked potentials (AEPs) are neuroelectric brain responses recorded at the scalp which

  2. Electrocutaneous reflexes and multimodality evoked potentials in multiple sclerosis

    Microsoft Academic Search

    W G Friedli; P Fuhr

    1990-01-01

    Electrical stimulation of the digital nerves of the index finger produces changes in the EMG signal during steady voluntary contraction of the first dorsal interosseous muscle. This electrocutaneous reflex (ECR) was studied in 90 patients classified into different categories according to diagnostic criteria for multiple sclerosis. In addition, pattern reversal visual evoked responses (VER), brainstem auditory evoked responses (BAER) as

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

    PubMed

    Piazza, S; Huynh, M; Cauzinille, L

    2014-06-01

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

  4. SUMMARY OF WORKSHOP III: EVOKED POTENTIALS

    EPA Science Inventory

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

  5. Cochlear potentials and auditory evoked potentials in the caiman (Caiman crocodilus (L.)).

    PubMed

    Smolders, J W; Caird, D M; Klinke, R

    1990-02-01

    Brain-stem auditory evoked potentials (BAEPs) and round window compound action potentials (CAPs) in response to rarefaction and condensation clicks were recorded from anaesthetized and artificially respired caiman. The recorded wave forms were substantially different from the brain-stem and round window potentials recorded in mammals, including man. In particular, wave latencies were much longer than in mammals. Wave amplitudes increased and latencies decreased significantly and reversibly with increases in stimulus intensity and body temperature. The latencies of the first positive wave (P1) in the BAEP and the first negative wave (N1) in the CAP are correlated and co-vary with stimulus level and body temperature. BAEP P1 thus represents the response of the auditory nerve. The cochlear microphonic (CM) latency in caiman is unaffected by stimulus intensity and by cooling of the animal. PMID:1688779

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

    PubMed Central

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

    2012-01-01

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

  7. Functional status of auditory pathways in hypothyroidism: evoked potential study.

    PubMed

    Anjana, Yumnam; Vaney, Neelam; Tandon, O P; Madhu, S V

    2006-01-01

    Hypothyroidism is known to be associated with mental retardation, motor dysfunction, memory deficits and hearing impairment. In the present study, the functional integrity of the thalamocortical projections to the primary auditory cortex and association cortex has been assessed by using Auditory Evoked Responses i.e Auditory Brainstem (ABR), Mid Latency Response (MLR) and Slow Vertex Response (SVR). Thirty newly diagnosed hypothyroid patients and thirty healthy controls were taken for the study and ABR, MLR and SVR were recorded on computerized evoked potential recorder using 10-20 system of electrode placement. The second recordings for the hypothyroid patients were done 3 months after treatment with attainment of euthyroid states. The present study revealed a slight increase in absolute latency of wave III of ABR in hypothyroid patients and significant decrease in absolute latency of wave III and interpeak latency of I-III after treatment. There was a significant decrease in amplitude of wave V in hypothyroid patients and significant increase in amplitudes of ABR wave I and wave V after treatment. There was a significant increase in latency of wave Na of MLR and wave P2 of SVR in hypothyroid patients. The latencies of waves Na, Pa, Nb of MLR and waves PI and N2 of SVR showed significant improvement with thyroid hormone treatment. The results of the present study indicates that in hypothyroid state there might be slow conduction at the periphery and with treatment there is better recruitment of neuronal pool of the generators of the waves of ABR in the brainstem. We can also conclude that the thalamocortical projections of the auditory pathways are adversely affected in the hypothyroid state and this improves after treatment. PMID:17402263

  8. Hearing function and auditory evoked potentials in children with spastic forms of cerebral palsy

    Microsoft Academic Search

    I. A. Kolker

    2004-01-01

    We studied auditory short-latency brainstem and long-latency cortical evoked potentials (EP)in 62 healthy children and 126 children with spastic forms of children’s cerebral palsy, CP (spastic tetraparesis, spastic diplegia, and left-and right-side hemiplegias). An increase in the thresholds of audibility (independently of the CP form) was the most typical disturbance of the function of hearing revealed by the analysis of

  9. Sound alters visual evoked potentials in humans

    Microsoft Academic Search

    Ladan Shams; Yukiyasu Kamitani; Samuel Thompson; Shinsuke Shimojo

    2001-01-01

    When a single ?ash is accompanied by two auditory beeps, the single ?ash is perceived as two ?ashes. We investigated whether this crossmodal in?uence on visual perception occurs at the level of the modality-specific visual pathway or later. We compared the visual evoked potentials (VEPs) in the presence and absence of sound. Activity was modulated extensively and with short latency

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

    PubMed Central

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

    2014-01-01

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

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

    PubMed

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

    2014-06-01

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

  12. The mouse visually evoked potential : neural correlates and functional applications

    E-print Network

    Muhammad, Rahmat

    2009-01-01

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

  13. Cortical potentials evoked by nociceptive stimuli

    PubMed Central

    Leme, J. Garcia; Lico, Maria

    1974-01-01

    1 The amplitudes of the first positive and the first negative waves of cortical potentials evoked by electrical stimulation of the dental pulp in the rat were decreased following electrical stimulation of the peripheral cut end of the saphenous nerve. 2 This effect was greatly diminished when the stimulation of the saphenous nerve was performed with the saphenous or femoral veins ligated. 3 During stimulation of the saphenous nerve of a donor rat, the subcutaneous tissue in the area supplied by the nerve was perfused; when the perfusate (in which a permeability-increasing factor was detected) was injected intravenously into a recipient animal, a decrease in the amplitude of the evoked cortical potential of the recipient rat was also observed. 4 Intravenous injections of 5-hydroxytryptamine, histamine, bradykinin, prostaglandins or adenosine-triphosphate produced no effect on the evoked cortical potential, whereas large doses of acetylsalicylic acid caused a decrease. 5 It is suggested that a humoral factor, released during sensory nerve stimulation, may help to modulate the processing of afferent inputs from pain receptors. PMID:4615762

  14. Rectal sensory evoked potentials: an Assessment of their clinical value

    Microsoft Academic Search

    C. T. M. Speakman; M. A. Kamm; M. Swash

    1993-01-01

    To assess abnomalities of sensory conduction in anorectal disease we have evaluated peripheral sensory perception and somatosensory evoked potentials produced by rectal stimulation in control subjects and patients with either constipation or idiopathic faecal incontinence. Evoked potentials were also recorded after posterior tibial and dorsal genital nerve stimulation. Rectal sensation was also assessed using electrical stimulation. Reproducible evoked potential recordings

  15. Role of Brainstem GABAergic signaling in Central Cannabinoid Receptor evoked Sympathoexcitation and Pressor Response in Conscious Rats

    PubMed Central

    Ibrahim, Badr Mostafa; Abdel-Rahman, Abdel A.

    2011-01-01

    The mechanisms implicated in the sympathoexcitation and pressor the response elicited by central CB1R activation are not fully understood. Further, the few reported mechanistic studies on this endeavor were conducted in anesthetized rats. Therefore, it was important to identify the dose-related cardiovascular responses elicited by central administration of the cannabinoid receptor (CB1R) agonist WIN55,212-2 in conscious rats. The second and main objective of the study was to test the hypothesis that brainstem GABAergic transmission is implicated in the CB1R-evoked sympathoexcitation/pressor response. In conscious rats, intracisternal (i.c) WIN55,212-2 (3, 10, 30 ?g/rat) elicited dose-dependent increases in mean arterial pressure (MAP) and plasma norepinephrine (NE; index of sympathoexcitation), and reduced heart rate (HR). Subsequent neurochemical studies showed that i.c WIN55,212-2 (15 ?g/rat) significantly increased the number and percentage of neurons that exhibited dual immunostaining for tyrosine hydroxylase (catecholaminergic neurons) and c-Fos (marker of neuronal activity) within the rostral ventrolateral medulla, which suggests enhanced central sympathetic tone. These neurochemical responses along with the increases in MAP and plasma NE were drastically attenuated by prior: (i) blockade of central CB1R by i.c AM251 (30 ?g/rat) or (ii) activation of central GABAAR by i.c muscimol (0.1 ?g/rat). Collectively, these neurochemical and cardiovascular findings are the first to suggest a pivotal role for the inhibition of brainstem GABAergic transmission in the central CB1R-evoked sympathoexcitation/pressor responses in conscious rats. PMID:21840505

  16. Trigeminal evoked potentials: origins in the cat.

    PubMed

    Dong, W K

    1982-02-01

    Short latency brain stem (far-field) and cortical (early-field) potentials were evoked by stimulation of the main nerve epidurally over the primary sensorimotor cortex. The specific generators of these volume conducted potentials were identified from both lesion and recording studies in the trigeminal lemniscal system. Far-field components I, II and III, respectively, originate from the semilunar ganglion, trigeminal lemniscus and thalamocortical radiation; whereas early near-field components P1 and N1 originate from the cortical cell layers. PMID:6277424

  17. 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.

  18. Conditions for evoked-potential audiometry in odontocetes

    NASA Astrophysics Data System (ADS)

    Supin, Alexander Ya.

    2005-04-01

    Currently auditory brainstem evoked potentials (ABR) become widely used for audiometry in odontocetes. Depending on the goal, the ABR technique differs with respect of (i) electrode positions, (ii) stimulus parameters, and (iii) threshold evaluation procedure. (I) Optimal electrode positions are vertex (for binaural responses), lateral (for monaural responses), or pharyngeal (for some express investigations). (II) The shorter the stimulus and the wider its spectrum, the more robust the response. Thereafter, narrow-band stimuli provoke low-amplitude ABR with a short dynamic range, but the goal of investigation often requires keeping the stimulus spectrum narrow. Sinusoidally amplitude modulated (SAM) sounds have narrow spectra, thereby provoking low amplitude envelope-following response (EFR); however, EFR can be extracted from noise by Fourier analysis. Modulation rate for SAM sounds must fit a spectrum peak of the ABR waveform. High-frequency sounds are more effective to provoke ABR and EFR than low-frequency ones, so ABR technique is better applicable for measurements in high-frequency ranges. (III) For precise threshold evaluation, low-amplitude responses must be extracted from noise. Apart from the averaging procedure, cross-correlation (for single ABR) or Fourier (for EFR) analysis is helpful to extract and measure low response amplitudes. [Work supported by Russian Basic Research Foundation, Russian President Grant, ONR.

  19. SURFACE DISTRIBUTION OF FLASH-EVOKED AND PATTERN REVERSAL-EVOKED POTENTIALS IN HOODED RATS

    EPA Science Inventory

    Stimultaneous recording from 21 electrode sites in a 4x4 mm area over the posterior cortex was used to determine the surface distribution of all major peaks which constitute flash evoked potentials (FEPs) and pattern reversal evoked potentials (PREPs) in hooded rats. Topographica...

  20. Modeling and estimation of single evoked brain potential components

    Microsoft Academic Search

    Daniel H. Lange; Hillel Pratt; Gideon F. Inbar

    1997-01-01

    Presents a novel approach to solving the single-trial evoked-potential estimation problem. Recognizing that different components of an evoked potential complex may originate from different functional brain sites and can be distinguished according to their respective latencies and amplitudes, the authors propose an estimation approach based on identification of evoked potential components on a single-trial basis. The estimation process is performed

  1. Cervicothoracic Multisegmental Transpinal Evoked Potentials in Humans

    PubMed Central

    Einhorn, Jonathan; Li, Alan; Hazan, Royi; Knikou, Maria

    2013-01-01

    The objectives of this study were to establish the neurophysiological properties of the transpinal evoked potentials (TEPs) following transcutaneous electric stimulation of the spine (tsESS) over the cervicothoracic region, changes in the amplitude of the TEPs preceded by median nerve stimulation at group I threshold, and the effects of tsESS on the flexor carpi radialis (FCR) H-reflex in thirteen healthy human subjects while seated. Two re-usable self-adhering electrodes, connected to function as one electrode (cathode), were placed bilaterally on the clavicles. A re-usable electrode (anode) was placed on the cervicothoracic region covering from Cervical 4 – Thoracic 2 and held under constant pressure throughout the experiment. TEPs were recorded bilaterally from major arm muscles with subjects seated at stimulation frequencies of 1.0, 0.5, 0.33, 0.2, 0.125, and 0.1 Hz, and upon double tsESS pulses delivered at an inter-stimulus interval of 40 ms. TEPs from the arm muscles were also recorded following median nerve stimulation at the conditioning-test (C-T) intervals of 2, 3, 5, 8, and 10 ms. The FCR H-reflex was evoked and recorded according to conventional methods following double median nerve pulses at 40 ms, and was also conditioned by tsESS at C-T intervals that ranged from ?10 to +50 ms. The arm TEPs amplitude was not decreased at low-stimulation frequencies and upon double tsESS pulses in all but one subject. Ipsilateral and contralateral arm TEPs were facilitated following ipsilateral median nerve stimulation, while the FCR H-reflex was depressed by double pulses and following tsESS at short and long C-T intervals. Non-invasive transpinal stimulation can be used as a therapeutic modality to decrease spinal reflex hyper-excitability in neurological disorders and when combined with peripheral nerve stimulation to potentiate spinal output. PMID:24282479

  2. Methods for quantifying intra- and inter-subject variability of evoked potential data applied to the multifocal visual evoked potential

    Microsoft Academic Search

    Sangita Dandekar; Justin Ales; Thom Carney; Stanley A. Klein

    2007-01-01

    Differences in cortical geometry within and between subjects can complicate multifocal visual evoked potential (mfVEP) and standard evoked potential (EP) intra- and inter-subject comparisons. We present methods for aligning temporal intra- and inter-subject data prior to comparison.Multiple groups have informally observed that the two dominant temporal principal components (PCs) of the pattern reversal visual evoked potential (VEP) obtained with singular

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

    PubMed Central

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

    2012-01-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2012-02-01

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

  5. Limitations in the rapid extraction of evoked potentials using parametric modeling.

    PubMed

    De Silva, A C; Sinclair, N C; Liley, D T J

    2012-05-01

    The rapid extraction of variations in evoked potentials (EPs) is of great clinical importance. Parametric modeling using autoregression with an exogenous input (ARX) and robust evoked potential estimator (REPE) are commonly used methods for extracting EPs over the conventional moving time average. However, a systematic study of the efficacy of these methods, using known synthetic EPs, has not been performed. Therefore, the current study evaluates the restrictions of these methods in the presence of known and systematic variations in EP component latency and signal-to-noise ratios (SNR). In the context of rapid extraction, variations of wave V of the auditory brainstem in response to stimulus intensity were considered. While the REPE methods were better able to recover the simulated model of the EP, morphology and the latency of the ARX-estimated EPs was a closer match to the actual EP than than that of the REPE-estimated EPs. We, therefore, concluded that ARX rapid extraction would perform better with regards to the rapid tracking of latency variations. By tracking simulated and empirically induced latency variations, we conclude that rapid EP extraction using ARX modeling is only capable of extracting latency variations of an EP in relatively high SNRs and, therefore, should be used with caution in low-noise environments. In particular, it is not a suitable method for the rapid extraction of early EP components such as the auditory brainstem potential. PMID:22394572

  6. Auditory Evoked Potentials and Impairments to Psychomotor Activity Evoked by Falling Asleep

    Microsoft Academic Search

    V. B. Dorokhov; Yu. S. Verbitskaya; T. P. Lavrova

    2010-01-01

    Sounds provide the most suitable stimuli for studies of information processes occurring in the brain during falling asleep\\u000a and at different stages of sleep. The widely used analysis of evoked potentials averaged for groups of subjects has a number\\u000a of disadvantages associated with their individual variability. Thus, in the present study, measures of the individual components\\u000a of auditory evoked potentials

  7. Auditory image movement in evoked potentials.

    PubMed

    Altman, J A; Vaitulevich, S F

    1990-04-01

    Long-latency auditory evoked potentials (AEPs) were tested in subjects following binaural stimulation with click trains with gradually changing interaural time delays (delta Ts). With appropriate change of the delta Ts this sound signal could produce the sensation of a moving fused auditory image (FI). It was found that the N1-P2 complex of the AEPs rose in amplitude with the increase of the click rate above 15 Hz, and to a greater extent for the moving than for the unmoved FIs. Binaural release from masking (as measured by the binaural masking level difference (BMLD) for the AEPs) amounted to 6 dB for the unmoved FI. For the moving FI the BMLD for the AEPs amounted to 2.8 and 3.5 dB in men and 13.4 and 11.3 dB in women, for the left and right hemispheres respectively. The amplitude of the N1-P2 complex following stimulation with the 'moving' and 'unmoved' sounds was larger in women than in men. PMID:1691080

  8. Auditory evoked potential measurements in elasmobranchs

    NASA Astrophysics Data System (ADS)

    Casper, Brandon; Mann, David

    2005-04-01

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

  9. Neurophysiological studies of patients with classical phenylketonuria: evaluation of results of IQ scores, EEG and evoked potentials.

    PubMed

    Co?kun, T; Topçu, M; Ustünda?, I; Ozalp, I; Renda, Y; Ci?er, A; Nurlu, G

    1993-01-01

    Neurophysiological studies were conducted in 42 patients with classical phenylketonuria. The results of the intelligence quotient scores, electroencephalogram, visual evoked potentials and brain-stem auditory evoked potentials were evaluated. When compared with the controls, the subjects demonstrated a significant prolongation in VEP P1 and BAEP I-V interpeak latencies and an increase in VEP N1P1 amplitudes. No relationship was found between these pathological responses and metabolic control. However, the observation of normal intelligence quotient scores in 14 out of 18 patients who displayed a pathological prolongation in P1 latencies led us to the conclusion that evoked potentials may have a significant role in the determination of neurophysiological defects and that even cases with good metabolic control may have some obscure neurophysiological dysfunction which should be evaluated more carefully. PMID:8236512

  10. Conventional and cross-correlation brain-stem auditory evoked responses in the white leghorn chick: rate manipulations

    NASA Technical Reports Server (NTRS)

    Burkard, R.; Jones, S.; Jones, T.

    1994-01-01

    Rate-dependent changes in the chick brain-stem auditory evoked response (BAER) using conventional averaging and a cross-correlation technique were investigated. Five 15- to 19-day-old white leghorn chicks were anesthetized with Chloropent. In each chick, the left ear was acoustically stimulated. Electrical pulses of 0.1-ms duration were shaped, attenuated, and passed through a current driver to an Etymotic ER-2 which was sealed in the ear canal. Electrical activity from stainless-steel electrodes was amplified, filtered (300-3000 Hz) and digitized at 20 kHz. Click levels included 70 and 90 dB peSPL. In each animal, conventional BAERs were obtained at rates ranging from 5 to 90 Hz. BAERs were also obtained using a cross-correlation technique involving pseudorandom pulse sequences called maximum length sequences (MLSs). The minimum time between pulses, called the minimum pulse interval (MPI), ranged from 0.5 to 6 ms. Two BAERs were obtained for each condition. Dependent variables included the latency and amplitude of the cochlear microphonic (CM), wave 2 and wave 3. BAERs were observed in all chicks, for all level by rate combinations for both conventional and MLS BAERs. There was no effect of click level or rate on the latency of the CM. The latency of waves 2 and 3 increased with decreasing click level and increasing rate. CM amplitude decreased with decreasing click level, but was not influenced by click rate for the 70 dB peSPL condition. For the 90 dB peSPL click, CM amplitude was uninfluenced by click rate for conventional averaging. For MLS BAERs, CM amplitude was similar to conventional averaging for longer MPIs.(ABSTRACT TRUNCATED AT 250 WORDS).

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

    PubMed Central

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

    2014-01-01

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

  12. Specialization of the auditory processing in harbor porpoise, characterized by brain-stem potentials

    NASA Astrophysics Data System (ADS)

    Bibikov, Nikolay G.

    2002-05-01

    Brain-stem auditory evoked potentials (BAEPs) were recorded from the head surface of the three awaked harbor porpoises (Phocoena phocoena). Silver disk placed on the skin surface above the vertex bone was used as an active electrode. The experiments were performed at the Karadag biological station (the Crimea peninsula). Clicks and tone bursts were used as stimuli. The temporal and frequency selectivity of the auditory system was estimated using the methods of simultaneous and forward masking. An evident minimum of the BAEPs thresholds was observed in the range of 125-135 kHz, where the main spectral component of species-specific echolocation signal is located. In this frequency range the tonal forward masking demonstrated a strong frequency selectivity. Off-response to such tone bursts was a typical observation. An evident BAEP could be recorded up to the frequencies 190-200 kHz, however, outside the acoustical fovea the frequency selectivity was rather poor. Temporal resolution was estimated by measuring BAER recovery functions for double clicks, double tone bursts, and double noise bursts. The half-time of BAERs recovery was in the range of 0.1-0.2 ms. The data indicate that the porpoise auditory system is strongly adapted to detect ultrasonic closely spaced sounds like species-specific locating signals and echoes.

  13. Click-evoked potentials on the neck of the guinea pig.

    PubMed

    Matsuzaki, Masaki; Murofushi, Toshihisa

    2002-03-01

    Vestibulocollic reflex in humans is called vestibular evoked myogenic potential. To try to establish an animal model of the acoustically evoked vestibulocollic reflex, 18 guinea pigs were used in this study. Eight of the 18 guinea pigs received intramuscular injection of amikacin for 18 days (450 mg/kg/day) before recording to destroy the cochlea pharmacologically. Under general anesthesia with intraperitoneal injection of pentobarbital sodium (40 mg/kg body weight), auditory brainstem responses (ABRs) were recorded. Then potentials on the neck evoked by loud clicks were recorded on the pre-vertebral muscle or on the spinal cord at the level of third cervical vertebral bone using a silver-ball electrode. As a result, a negative peak (NP) with a latency of 6 approximately 8 ms was observed on the neck muscle or on the spinal cord in the control group. The thresholds of the NP were 90-100 dB above those of ABRs. The NP was also observed in the amikacin-administered group using clicks with the same intensity as that for the control group, while the ABR thresholds were highly elevated. These results are in agreement with a vestibular origin of the NP potential. PMID:12031524

  14. KETAMINE ALTERS RAT FLASH EVOKED POTENTIALS (JOURNAL VERSION)

    EPA Science Inventory

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

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

    E-print Network

    Prakash, Srinivasamurthy Ravi

    2009-01-01

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

  16. USE OF SENSORY EVOKED POTENTIALS IN NEUROTOXICITY TESTING OF WORKERS

    EPA Science Inventory

    Electrophysiological measures appropriate for use in neurotoxicity testing of workers are briefly reviewed. These measures include auditory, visual and somatosensory evoked potentials. Relevant human studies are reviewed. Selection criteria, strengths and weaknesses are discussed...

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

    EPA Science Inventory

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

  18. Steady-state visual evoked potentials and travelling waves

    Microsoft Academic Search

    Guy R Burkitt; Richard B Silberstein; Peter J Cadusch; Andrew W Wood

    2000-01-01

    Objective: The amplitude and phase of the steady-state visual evoked potential (SSVEP) is sensitive to cognition and attention but the underlying mechanism is not well understood. This study examines stimulus evoked changes in the SSVEP phase topography and the putative role of travelling waves.Methods: Eighteen subjects viewed a central-field checkerboard and full-field flicker stimulus temporally modulated at the peak alpha

  19. ROLE OF NMDA, NICOTINIC, AND GABA RECEPTORS IN THE STEADY STATE VISUAL EVOKED POTENTIAL IN RATS.

    EPA Science Inventory

    This manuscript characterizes the receptor pathways involved in pattern-evoked potential generation in rats " NMDA and nicotinic acetylcholine receptors appear to be involved in the generation of the steady-state pattern evoked response in vivo. " The pattern evok...

  20. Surgical management of brain-stem cavernomas

    Microsoft Academic Search

    Ulrich Pechstein; Josef Zentner; Dirk Van Roost; Johannes Schramm

    1997-01-01

    We present a series of seven patients who were operated on for symptomatic brain-stem cavernomas. The following approaches were used: medial suboccipital (N = 4), lateral suboccipital (N = 1), subtemporal-transtentorial (N = 1), and frontal transcortical-transventricular-subchorioidaltrans velum interpositum (N = 1). Intraoperative motor (N = 4) and somatosensory (N = 1) evoked potential monitoring revealed temporary changes in 3

  1. [Clinical application of pain-related evoked potentials].

    PubMed

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

    2012-02-01

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

  2. Effects of remote cutaneous pain on trigeminal laser-evoked potentials in migraine patients.

    PubMed

    de Tommaso, Marina; Difruscolo, Olimpia; Sardaro, Michele; Libro, Giuseppe; Pecoraro, Carla; Serpino, Claudia; Lamberti, Paolo; Livrea, Paolo

    2007-06-01

    The present study aimed to evaluate heat pain thresholds and evoked potentials following CO(2) laser thermal stimulation (laser-evoked potentials, LEPs), during remote application of capsaicin, in migraine patients vs. non-migraine healthy controls. Twelve outpatients suffering from migraine without aura were compared with 10 healthy controls. The LEPs were recorded by 6 scalp electrodes, stimulating the dorsum of the right hand and the right supraorbital zone in basal condition, during the application of 3% capsaicin on the dorsum of the left hand and after capsaicin removal. In normal subjects, the laser pain and the N2-P2 vertex complex obtained by the hand and face stimulation were significantly reduced during remote capsaicin application, with respect to pre-and post-capsaicin conditions, while in migraine LEPs and laser pain were not significantly modified during remote painful stimulation. In migraine a defective brainstem inhibiting control may coexist with cognitive factors of focalised attention to facial pain, less sensitive to distraction by a second pain. PMID:17563842

  3. EVOKED POTENTIALS, PHYSIOLOGICAL METHODS WITH HUMAN APPLICATIONS

    EPA Science Inventory

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

  4. On hemispheric differences in evoked potentials to speech stimuli

    NASA Technical Reports Server (NTRS)

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

    1975-01-01

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

  5. Cortical Auditory Evoked Potentials in Unsuccessful Cochlear Implant Users

    ERIC Educational Resources Information Center

    Munivrana, Boska; Mildner, Vesna

    2013-01-01

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

  6. Evaluation of Evoked Potentials to Dyadic Tones after Cochlear Implantation

    ERIC Educational Resources Information Center

    Sandmann, Pascale; Eichele, Tom; Buechler, Michael; Debener, Stefan; Jancke, Lutz; Dillier, Norbert; Hugdahl, Kenneth; Meyer, Martin

    2009-01-01

    Auditory evoked potentials are tools widely used to assess auditory cortex functions in clinical context. However, in cochlear implant users, electrophysiological measures are challenging due to implant-created artefacts in the EEG. Here, we used independent component analysis to reduce cochlear implant-related artefacts in event-related EEGs of…

  7. VALIDITY OF SPECTRAL ANALYSIS OF EVOKED POTENTIALS IN BRAIN RESEARCH

    Microsoft Academic Search

    ALEXANDER V. KRAMARENKO; UNER TAN

    The averaged electronencephologram (EEG) response of the brain to an external stimulus (evoked potential, EP) is usually subjected to spec- tral analysis using the fast Fourier transform (FFT), especially to dis- cover the relation of cognitive ability to so-called brain dynamics. There is indeed a discrepancy between these two systems, because the brain is a highly complex nonlinear system, analyzed

  8. ONTOGENY OF FLASH-EVOKED POTENTIALS IN UNANESTHETIZED RATS

    EPA Science Inventory

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

  9. Effects of bilirubin on visual evoked potentials in term infants

    Microsoft Academic Search

    Yung-Jung Chen; Wun-Ming Kang

    1995-01-01

    To determine bilirubin-in- rants in the severe group had poor duced neurotoxicity, serial visual motor skills and one had general hy- evoked potentials (VEPs) of 72 in- potonia. fants with neonatal hyperbilirubi- naemia and 22 controls were evalu- ated and compared in four sessions for 8 weeks after birth. The levels of maximal serum bilirubin were found positively related to

  10. Motion adaptation in chromatic motion-onset visual evoked potentials

    Microsoft Academic Search

    D. J. McKeefry; W. Yorks

    2001-01-01

    The aim of this study was to investigate the influence of motion adaptation on visual evoked potentials (VEPs) elicited by the onset of isoluminant chromatic motion. VEPs were recorded from the occipital cortex of human subjects using a sinusoidal grating stimulus of one cycle per degree which moved at either a velocity of 2 or 10°\\/s and subtended a field

  11. COMPARABILITY OF RAT AND HUMAN VISUAL EVOKED POTENTIALS

    EPA Science Inventory

    A series of experiments was conducted to assess the comparability of physiological processes in rat and human visual systems. n the first set of experiments, transient visual evoked potentials (VEPs) were elicited by the onset of sine-wave gratings of various spatial frequencies....

  12. PATTERN REVERSAL VISUAL EVOKED POTENTIALS IN AWAKE RATS

    EPA Science Inventory

    A method for recording pattern reversal evoked potentials (PREPs) from awake restrained rats has been developed. The procedure of Onofrj et al. was modified to eliminate the need for anesthetic, thereby avoiding possible interactions of the anesthetic with other manipulations of ...

  13. Visual evoked potentials in workers with chronic solvent encephalopathy

    Microsoft Academic Search

    Maarten M. Verberk; Joke T. Brons; Herman J. A. Sallé

    2004-01-01

    Objectives Two promising variations of visual evoked potentials (VEPs) were studied in solvent-exposed workers: the effect of a low-contrast stimulus in comparison with the usually applied high contrast, and the ability of pattern-onset VEP to reveal damage to specific visual cortical areas. In addition, we studied disturbances of a visual event-related potential (P300). Methods Thirty male patients (48±9 years of

  14. The combined monitoring of brain stem auditory evoked potentials and intracranial pressure in coma. A study of 57 patients.

    PubMed Central

    García-Larrea, L; Artru, F; Bertrand, O; Pernier, J; Mauguière, F

    1992-01-01

    Continuous monitoring of brainstem auditory evoked potentials (BAEPs) was carried out in 57 comatose patients for periods ranging from 5 hours to 13 days. In 53 cases intracranial pressure (ICP) was also simultaneously monitored. The study of relative changes of evoked potentials over time proved more relevant to prognosis than the mere consideration of "statistical normality" of waveforms; thus progressive degradation of the BAEPs was associated with a bad outcome even if the responses remained within normal limits. Contrary to previous reports, a normal BAEP obtained during the second week of coma did not necessarily indicate a good vital outcome; it could, however, do so in cases with a low probability of secondary insults. The simultaneous study of BAEPs and ICP showed that apparently significant (greater than 40 mm Hg) acute rises in ICP were not always followed by BAEP changes. The stability of BAEP's despite "significant" ICP rises was associated in our patients with a high probability of survival, while prolongation of central latency of BAEPs in response to ICP modifications was almost invariably followed by brain death. Continuous monitoring of brainstem responses provided a useful physiological counterpart to physical parameters such as ICP. Serial recording of cortical EPs should be added to BAEP monitoring to permit the early detection of rostrocaudal deterioration. Images PMID:1402970

  15. Emotional modulation of pain-related evoked potentials?

    PubMed Central

    Ring, Christopher; Kavussanu, Maria; Willoughby, Adrian R.

    2013-01-01

    To investigate whether cortical processing of trigeminal nociception is modulated by emotion, the N2 and P2 components of the pain-related evoked potential (PREP) were recorded in response to noxious stimulation of the supraorbital nerve while participants viewed neutral, pleasant and unpleasant pictures. The nerve was stimulated at 125% of pain threshold via a nociceptive-specific concentric electrode to selectively activate A-delta pain fibres. The N2 and P2 pain-related evoked potentials were similarly influenced by emotional priming: the amplitude of both potentials decreased monotonically from viewing neutral to pleasant to unpleasant pictures. These findings show that cortical processing of trigeminal nociception is modulated by emotion. We explain our findings in terms of the effects of picture viewing on attention. PMID:23607998

  16. Dreams recall and auditory evoked potentials during propofol anaesthesia.

    PubMed

    Aceto, Paola; Congedo, Elisabetta; Lai, Carlo; Valente, Alessio; Gualtieri, Elisabetta; De Cosmo, Germano

    2007-05-28

    It is unclear whether shorter wave latencies of middle-latency-auditory-evoked-potentials may be associated to cognitive function other than nondeclarative memory. We investigated the presence of declarative, nondeclarative and dreaming memory in propofol-anaesthetized patients and any relationship to intraoperatively registered middle-latency-auditory-evoked-potentials. An audiotape containing one of two stories was presented to patients during anaesthesia. Patients were interviewed on dream recall immediately upon emergence from anaesthesia. Declarative and nondeclarative memories for intraoperative listening were assessed 24 h after awakening without pointing out positive findings. Six patients who reported dream recall showed an intraoperative Pa latency less than that of patients who were unable to remember any dreams (P<0.001). A high responsiveness degree of primary cortex was associated to dream recall formation during anaesthesia. PMID:17471074

  17. Establishing an evoked-potential vision-tracking system

    NASA Technical Reports Server (NTRS)

    Skidmore, Trent A.

    1991-01-01

    This paper presents experimental evidence to support the feasibility of an evoked-potential vision-tracking system. The topics discussed are stimulator construction, verification of the photic driving response in the electroencephalogram, a method for performing frequency separation, and a transient-analysis example. The final issue considered is that of object multiplicity (concurrent visual stimuli with different flashing rates). The paper concludes by discussing several applications currently under investigation.

  18. Investigating Visual Function with Multifocal Visual Evoked Potentials

    Microsoft Academic Search

    Michael B. Hoffmann

    ? With multifocal visual evoked potentials (mfVEPs) the visual field can be sampled for response abnormalities. Thus, mfVEPs\\u000a open the possibility of an objective visual field test. The issue, however, is greatly complicated by the variability of the\\u000a responses across the visual field and between subjects. \\u000a \\u000a ? Cortical morphology dictates the mfVEP shape and influences mfVEP magnitude; consequently it is

  19. Visual evoked potentials in rotogravure printers exposed to toluene

    Microsoft Academic Search

    P Urban; E Lukás

    1990-01-01

    Visual evoked potentials (VEPs) from stimulation by checkerboard pattern reversal were examined in 54 rotogravure printers exposed to toluene (all men, aged 22-64 years, duration of exposure 1-41 years). A control group consisted of 46 subjects (23 men and 23 women; aged 22-54 years). Compared with controls the exposed group showed more frequent responses with reduced reproducibility or absence of

  20. Laser flash effects on laser speckle shift visual evoked potential

    Microsoft Academic Search

    ELMAR T. SCHMEISSER

    1985-01-01

    Steady-state visual evoked potentials (VEP's) were recorded from four cynomolgus monkeys in response to a sinusoidally oscillating 10 degrees helium-neon laser speckle field (632.8 nm), moving vertically 2.5 degrees at 8 shifts per second. A 5-pulse flash train at the maximum permissible exposure (MPE) dose from a collimated Q-switched frequency-doubled neodymium laser (532 nm) was superimposed on the foveal stimulus

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

    Microsoft Academic Search

    N. E. Vasilevskaya; L. N. Stankevich

    1976-01-01

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

  2. Determination of sources using brain-evoked potential maps

    NASA Astrophysics Data System (ADS)

    Amir, Avner; Jewett, Don L.

    1993-08-01

    Methods to localize the sources of Brain Evoked Potential Maps based on modeling of the sources as point dipoles have been widely used for more than twenty years. Such methods still lack a basic theory which can answer questions regarding the resolution and uniqueness of the results in the context of a realistic head model, with no a prior restrictions on the sources. In the first part of the paper we present simple physical models for the origin of far-field potentials associated with the auditory and somatosensory systems. An action potential travels along a straight axon can only produce a quadrupole field at far distances. We show that the far field potentials must originate when the action potential passes through a bent axon or through changes in the conductivities or in the external boundaries of the volume conductor surrounding the axon. We discuss the question of uniqueness of the solution for the 'inverse problem' of evoked potentials. This problem involved the reconstruction of the location and pattern of activity of the neuronal generators in the brain, given the map of the scalp electric potentials. We show that in a head shape with a realistic geometry spatially distinct points, line or open surface generators cannot create the same scalp potential map. The same applies to two non-overlapping generators occupying finite volumes.

  3. CHLORDIMEFORM PRODUCES CONTRAST-DEPENDENT CHANGES IN VISUAL EVOKED POTENTIALS OF HOODED RATS

    EPA Science Inventory

    Acute exposure to the insecticide/acaricide chlordimeform (CDM) produces large, selective and transient changes in visual evoked potentials of rats. Experiments were conducted investigating the influence of physical characteristics of the evoking stimuli on the CDM effect. Adult ...

  4. 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.

  5. Benign segmental myoclonus: electrophysiological evidence of transient dysfunction in the brainstem.

    PubMed

    Yoshikawa, H; Takamori, M

    2001-01-01

    We present a 66-year-old patient with segmental myoclonus evoked by a brainstem infarction. The myoclonus appeared soon after a cerebrovascular accident and it was evident in the soft palate, jaw, neck, shoulders and upper limbs. Brain MRI showed infarction in the left pons and left cerebellum. Small amounts of orally administered clonazepam were remarkably effective. Electroencephalogram (EEG) and auditory brainstem response (ABR) were normal. Somatosensory evoked potential (SSEP) revealed delays in P 14 and N19 recorded at C3 by right median nerve stimulation. These findings were normalized in 4 days. Seg-mental myoclonus is thought to be evoked by olivary hypertrophy following cerebrovascular accident in the brainstem and is said to be resistant to medication. The limited involvement of the brainstem in our patient may account for the transient segmental myoclonus. The prognosis for this type of segmental myoclonus is excellent. PMID:11148081

  6. Spinal somatosensory evoked potentials after epidural isoproterenol in awake sheep

    Microsoft Academic Search

    Marco A. E. Marcus; Frans L. Bruyninckx; Jan D. Vertommcn; Patrick F. Wouters; Hugo Van Aken

    1997-01-01

    Purpose  The use of 10–15 ?g epinephrine as an epidural test-dose is controversial. Isoproterenol would be a better alternative. However\\u000a before 5?g isoproterenol can be incorporated in an epidural test-dose, neurotoxicological studies have to be performed. The\\u000a present study was designed to assess spinal somatosensory evoked potentials (spinal SSEP) before and after epidural isoproteronol.\\u000a \\u000a \\u000a \\u000a Methods  Spinal SSEPs were recorded before, 30 min

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

    PubMed Central

    Grosprêtre, Sidney; Martin, Alain

    2014-01-01

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

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

    PubMed

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

    2015-02-01

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

  9. The effect of preterm birth on vestibular evoked myogenic potentials in children

    PubMed Central

    Eshaghi, Zahra; Jafari, Zahra; Shaibanizadeh, Abdolreza; Jalaie, Shohreh; Ghaseminejad, Azizeh

    2014-01-01

    Background: Preterm birth is a significant global health problem with serious short- and long-term consequences. This study examined the long term effects of preterm birth on vestibular evoked myogenic potentials (VEMPs) among preschool-aged children. Methods: Thirty-one children with preterm and 20 children with term birth histories aged 5.5 to 6.5 years were studied. Each child underwent VEMPs testing using a 500 Hz tone-burst stimulus with a 95 dB nHL (normal hearing level) intensity level. Results: The mean peak latencies of the p13 and n23 waves in the very preterm group were significantly longer than for the full-term group (p? 0.041). There was a significant difference between very and mildly preterm children in the latency of peak p13 (p= 0.003). No significant differences existed between groups for p13-n23 amplitude and the interaural amplitude difference ratio. The tested ear and gender did not affect the results of the test. Conclusion: Prolonged VEMPs in very preterm children may reflect neurodevelopmental impairment and incomplete maturity of the vestibulospinal tract (sacculocollic reflex pathway), especially myelination. VEMPs is a non-invasive technique for investigating the vestibular function in young children, and considered to be an appropriate tool for evaluating vestibular impairments at the low brainstem level. It can be used in follow-ups of the long-term effects of preterm birth on the vestibular system. PMID:25405140

  10. Evoked trigeminal nerve potential in chronic trichloroethylene intoxication

    SciTech Connect

    Barret, L.; Arsac, P.; Vincent, M.; Faure, J.; Garrel, S.; Reymond, F.

    1982-06-01

    Results of a study of trigeminal nerve impairment resulting from trichloroethylene intoxication by the somatosensory-evoked potential method reveal three kinds of abnormalities: increased stimulation voltage, excessive latency delay with morphological abnormalities, and excessive graph amplitude. These abnormalities confirm clinical disturbance (hypesthesia of the trigeminal nerve area) and open debate about the real mechanism of trichloroethylene neurotoxicity. Industrial intoxication by solvents, particularly trichloroethylene, is common. We have conducted a study of 188 workers chronically exposed to trichloroethylene and have confirmed the selective neurological disturbances of this intoxication in the trigeminal nerve (20%) (3, 10). We utilized a new experimental method, developed for studies of chronic intoxications effecting the median nerve (5, 8), of recording the somatosensory evoked potential following stimulation of the trigeminal nerve (4, 6, 7). The workers in this study were selected following clinical evaluation of their facial sensitivity and trigeminal nerve reflexes. In this paper we present our preliminary results on 11 workers, 9 suffering effects of intoxication and 2 controls.

  11. Auditory and somatosensory evoked potentials in brain-dead patients.

    PubMed

    Facco, E; Caputo, P; Casartelli Liviero, M; Munari, M; Toffoletto, F; Fabiani, F; Giron, G

    1988-01-01

    The short latency evoked potentials, allowing to assess the brain stem's function, can supply useful information in the diagnosis of Brain Death (BD). 15 BD patients were submitted to the auditory brain stem response (ABR); in 7 cases somatosensory evoked potentials from the medial nerve (SEP) were also recorded. The ABR was absent in 11 cases (73.3%), while in 3 cases only the I wave was present (20%); in one case the low-voltage I-V waves were present. Regarding the SEP, in 3 cases (42.9%) only the N9-N13 and P9-P13 waves were present, while in another 3 cases (42.9%) a N13/P13 dissociation was observable. In the remaining case, which presented a still reproducible I-V interval, the SEP was normal, thus excluding the diagnosis of BD. The ABR and the SEP, which are not roughly influenced by general anaesthetics and sedatives, are thus helpful in diagnosing BD. The SEP seems able to supply useful information more frequently than the ABR, but their combined use can guarantee maximum security of excluding false positives. PMID:3194649

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

    PubMed

    Burkard, R; Voigt, H F

    1990-11-01

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

  13. The impact of emotion on respiratory-related evoked potentials

    PubMed Central

    von Leupoldt, Andreas; Vovk, Andrea; Bradley, Margaret M.; Keil, Andreas; Lang, Peter J.; Davenport, Paul W.

    2013-01-01

    Emotion influences the perception of respiratory sensations, although the specific mechanism underlying this modulation is not yet clear. We examined the impact of viewing pleasant, neutral, and unpleasant affective pictures on the respiratory-related evoked potential (RREP) elicited by a short inspiratory occlusion in healthy volunteers. Reduced P3 amplitude of the RREP was found for respiratory probes presented when viewing pleasant or unpleasant series, when compared to those presented during the neutral series. Earlier RREP components, such as Nf, P1, N1, and P2, showed no modulation by emotion. The results suggest that emotion impacts the perception of respiratory sensations by reducing the attentional resources available for processing afferent respiratory sensory signals. PMID:20070570

  14. Auditory Evoked Potential Response and Hearing Loss: A Review

    PubMed Central

    Paulraj, M. P; Subramaniam, Kamalraj; Yaccob, Sazali Bin; Adom, Abdul H. Bin; Hema, C. R

    2015-01-01

    Hypoacusis is the most prevalent sensory disability in the world and consequently, it can lead to impede speech in human beings. One best approach to tackle this issue is to conduct early and effective hearing screening test using Electroencephalogram (EEG). EEG based hearing threshold level determination is most suitable for persons who lack verbal communication and behavioral response to sound stimulation. Auditory evoked potential (AEP) is a type of EEG signal emanated from the brain scalp by an acoustical stimulus. The goal of this review is to assess the current state of knowledge in estimating the hearing threshold levels based on AEP response. AEP response reflects the auditory ability level of an individual. An intelligent hearing perception level system enables to examine and determine the functional integrity of the auditory system. Systematic evaluation of EEG based hearing perception level system predicting the hearing loss in newborns, infants and multiple handicaps will be a priority of interest for future research.

  15. Effects of lead and mercury intoxications on evoked potentials

    SciTech Connect

    Lille, F.; Hazemann, P.; Garnier, R.; Dally, S.

    1988-01-01

    Pattern reversal, brain stem auditory and somatosensory evoked potentials (PREPs, BAEPs, SEPs) have been recorded on 13 patients occupationally exposed to inorganic lead compounds, in 9 patients occupationally or accidentally exposed to inorganic mercury compounds and in 26 chronic alcoholics. The results were compared to those of a normal control group. Peripheral conduction velocities were decreased in lead exposed workers and in alcoholics, but not modified in the mercury exposed patients. In the three exposed groups, an amplitude increase (PREPs and upper limb SEP cortical components), more important in the mercury group and an increase of central conduction time in case of lower limb stimulation, could be interpreted as early signs of nervous cortical impairment.

  16. Somatosensory evoked potentials in patients with sensitive dissociation.

    PubMed

    Psatta, D M; Matei, M

    1989-01-01

    The purpose of the study was to reconsider the somatosensory evoked potential (SEP) morphology in case of thermalgic versus proprioceptive sensory loss. The study was carried out on 70 inpatients affected by uni- or bilateral dissociated sensory disorders and on 45 normal controls. The median or tibial nerves were stimulated (at wrist or ankle), the stimulus intensity being adjusted to elicit a visible muscle response with liminal pain. SEPs were measured with regard to 7 negative components parameters (latency, amplitude) and statistically compared in the three groups. Results show that the initial SEP components (N18, N30, N70) are specifically affected in case of proprioceptive and the late components (N150, N220, N340) in case of thermalgic sensory disorders (N150 having an intermediate position). The intergroup differences were statistically significant. The results are thought to be used in clinical diagnosis. PMID:2609080

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

    E-print Network

    Paris-Sud XI, Université de

    EFFECTS OF TRANSCRANIAL DIRECT CURRENT STIMULATION (tDCS) ON SENSORY EVOKED POTENTIALS/computational modeling approach aimed at studying the effects of transcranial Direct Current Stimulation (t field, transcranial direct current stimulation, tDCS, local field potential, LFP, Evoked potential EP

  18. Post-exercise facilitation and depression of M wave and motor evoked potentials in healthy subjects

    Microsoft Academic Search

    Marianne Lentz; Jørgen Feldbæk Nielsen

    2002-01-01

    Objectives: To characterize so-called central fatigue, the effect of various levels of exercise on central and peripheral motor potentials were compared.Methods: Thirteen healthy subjects performed 4 levels of exercise following isometric dorsiflexion of the foot. Post-exercise recordings from the anterior tibial muscle of motor evoked potentials (MEP) evoked by transcranial magnetic stimulation (TMS) and M wave evoked by electrical stimulation

  19. Mapping human brain networks with cortico-cortical evoked potentials.

    PubMed

    Keller, Corey J; Honey, Christopher J; Mégevand, Pierre; Entz, Laszlo; Ulbert, Istvan; Mehta, Ashesh D

    2014-10-01

    The cerebral cortex forms a sheet of neurons organized into a network of interconnected modules that is highly expanded in humans and presumably enables our most refined sensory and cognitive abilities. The links of this network form a fundamental aspect of its organization, and a great deal of research is focusing on understanding how information flows within and between different regions. However, an often-overlooked element of this connectivity regards a causal, hierarchical structure of regions, whereby certain nodes of the cortical network may exert greater influence over the others. While this is difficult to ascertain non-invasively, patients undergoing invasive electrode monitoring for epilepsy provide a unique window into this aspect of cortical organization. In this review, we highlight the potential for cortico-cortical evoked potential (CCEP) mapping to directly measure neuronal propagation across large-scale brain networks with spatio-temporal resolution that is superior to traditional neuroimaging methods. We first introduce effective connectivity and discuss the mechanisms underlying CCEP generation. Next, we highlight how CCEP mapping has begun to provide insight into the neural basis of non-invasive imaging signals. Finally, we present a novel approach to perturbing and measuring brain network function during cognitive processing. The direct measurement of CCEPs in response to electrical stimulation represents a potentially powerful clinical and basic science tool for probing the large-scale networks of the human cerebral cortex. PMID:25180306

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

    PubMed

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

    2014-07-01

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

  1. [EEG and brain-stem evoked potentials in 125 recent concussions].

    PubMed

    Geets, W; Louette, N

    1983-12-01

    EEG and ipsi/contralateral BEPs have been recorded in 125 cases of concussion at most 48 h after the cerebral trauma. In 100 cases of minor concussion the temporary loss of consciousness lasted not more than 2 min. In 25 cases of mild concussion, the loss of consciousness lasted until their arrival at the hospital. In minor concussions an abnormal EEG was found in 17% of the cases and in mild concussions, in 56%. The abnormalities of the BEP, more often seen in mild concussions (60%) than in minor concussions (8%), are an increase of interpeak latencies or distorted responses with average to bad reproducibility. The results are discussed. PMID:6672896

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

    EPA Science Inventory

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

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

    PubMed Central

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

    2013-01-01

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

  4. AMPD2 regulates GTP synthesis and is mutated in a potentially treatable neurodegenerative brainstem disorder.

    PubMed

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

    2013-08-01

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

  5. Measuring action potential-evoked transmission at individual synaptic contacts

    PubMed Central

    Nauen, David W; Bi, Guo-Qiang

    2014-01-01

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

  6. Pattern Visual Evoked Potentials Elicited by Organic Electroluminescence Screen

    PubMed Central

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

    2014-01-01

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

  7. Facilitation of motor evoked potentials by somatosensory afferent stimulation.

    PubMed

    Deletis, V; Schild, J H; Beri?, A; Dimitrijevi?, M R

    1992-10-01

    The effect of an electrically induced peripheral afferent volley upon electrical and magnetic motor evoked potentials (MEPs) from muscles of the upper and lower extremities was studied in 16 healthy volunteers. A standard conditioning-test (C-T) paradigm was employed whereby the test stimulus (transcranial electric or magnetic) was applied at random time intervals, from 10 msec prior to 90 msec after the conditioning stimulus (peripheral nerve stimulus). MEP amplitude facilitation was observed for the majority of the upper extremity muscles tested at two distinct periods, one occurring at short, and the other at long C-T intervals. This bimodal trend of MEP facilitation was found to be equally as prominent in the lower extremity muscles tested. The period of short C-T interval facilitation is consistent with modifications in the spinal excitability of the segmental motoneuron pool. On the other hand, the period of long C-T interval facilitation is suggested to be due to alterations in excitability of the motor cortex as a result of the arrival of the orthodromic sensory volley. Although most pronounced in muscles innervated by the nerve to which the conditioning stimulus was applied, this bimodal facilitatory effect was also observed in adjacent muscles not innervated by the stimulated nerve. Qualitatively, the conditioned MEPs from the upper and lower extremities responded similarly to both electrical and magnetic trans-cranial stimulation. In addition, our study demonstrates that the C-T paradigm has potential for use in the assessment of spinal and cortical sensorimotor integration by providing quantitative information which cannot be obtained through isolated assessment of sensory and/or motor pathways.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:1385090

  8. Connections of the limbic network: a corticocortical evoked potentials study.

    PubMed

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

    2015-01-01

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

  9. Topographic distribution of the tibial somatosensory evoked potential using coherence.

    PubMed

    Melges, D B; Infantosi, A F C; Miranda de Sá, A M F L

    2008-12-01

    The objective of the present study was to determine the adequate cortical regions based on the signal-to-noise ratio (SNR) for somatosensory evoked potential (SEP) recording. This investigation was carried out using magnitude-squared coherence (MSC), a frequency domain objective response detection technique. Electroencephalographic signals were collected (International 10-20 System) from 38 volunteers, without history of neurological pathology, during somatosensory stimulation. Stimuli were applied to the right posterior tibial nerve at the rate of 5 Hz and intensity slightly above the motor threshold. Response detection was based on rejecting the null hypothesis of response absence (significance level alpha= 0.05 and M = 500 epochs). The best detection rates (maximum percentage of volunteers for whom the response was detected for the frequencies between 4.8 and 72 Hz) were obtained for the parietal and central leads mid-sagittal and ipsilateral to the stimulated leg: C4 (87%), P4 (82%), Cz (89%), and Pz (89%). The P37-N45 time-components of the SEP can also be observed in these leads. The other leads, including the central and parietal contralateral and the frontal and fronto-polar leads, presented low detection capacity. If only contralateral leads were considered, the centro-parietal region (C3 and P3) was among the best regions for response detection, presenting a correspondent well-defined N37; however, this was not observed in some volunteers. The results of the present study showed that the central and parietal regions, especially sagittal and ipsilateral to the stimuli, presented the best SNR in the gamma range. Furthermore, these findings suggest that the MSC can be a useful tool for monitoring purposes. PMID:19148367

  10. Pain-Related Evoked Potential in Healthy Adults

    PubMed Central

    Oh, Kyung Joon; Kim, Sung Hoon; Lee, Young-Hee; Kim, Jong Heon; Jung, Hong Sun; Park, Tae Jun; Park, Jin

    2015-01-01

    Objective To investigate the normal data of pain-related evoked potentials (PREP) elicited with a concentric surface electrode among normal, healthy adults and the relationship between PREP and pain intensity. Methods Sixty healthy volunteers (22 men and 38 women; aged 36.4±10.7 years; height, 165.4±7.8 cm) were enrolled. Routine nerve conduction study (NCS) was done to measure PREP following electrical stimulation of hands (C7 dermatome) and feet (L5 dermatome). Negative peak (N), positive peak (P) latencies, peak to peak (NP) amplitudes, conduction velocity (CV), and verbal rating scale (VRS) score were obtained. Linear regression analysis tested for significant relevance between variables of PREP and VRS score. Results Normal NCS results were obtained in all subjects. N latency of hand PREP was 163.8 ±40.0 ms (right) and 161.0±39.9 ms (left). N latency of foot PREP was 178.0±43.9 ms (right), 180.4±43.4 ms (left). NP amplitude of hands was 20.6±10.6 µV (right) and 21.9±11.6 µV (left). NP amplitude of feet was 18.8±8.3 µV (right) and 19.0±8.4 µV (left). The calculated CV was 13.2±4.7 m/s and VRS score was 3.8±1.0. A highly significant positive correlation was evident between VRS score and NP amplitude (y=0.1069x+1.781, r=0.877, n=60, p<0.0001). Conclusion PREP among normal, healthy adults revealed a statistically significant correlation between PREP amplitude and VRS score.

  11. Paying attention to orthography: a visual evoked potential study

    PubMed Central

    Herdman, Anthony T.; Takai, Osamu

    2013-01-01

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

  12. Evoked potentials in immobilized cats to a combination of clicks with painful electrocutaneous stimuli

    NASA Technical Reports Server (NTRS)

    Gilinskiy, M. A.; Korsakov, I. A.

    1979-01-01

    Averaged evoked potentials in the auditory, somatosensory, and motor cortical zones, as well as in the mesencephalic reticular formation were recorded in acute experiments on nonanesthetized, immobilized cats. Omission of the painful stimulus after a number of pairings resulted in the appearance of a delayed evoked potential, often resembling the late phases of the response to the painful stimulus. The characteristics of this response are discussed in comparison with conditioned changes of the sensory potential amplitudes.

  13. Aging affects transcranial magnetic modulation of hippocampal evoked potentials

    E-print Network

    Segal, Menahem

    antidepressant (TCA) are in gen- eral less effective in treating depression in aged patients than stimulation (TMS) is being proposed as a method of choice for the treatment of clinical depression, yet its of antidepressants is highly age-dependent, we studied possible age-related effects of TMS on hippocampal evoked

  14. Dynamics of Infant Cortical Auditory Evoked Potentials (CAEPs) for Tone and Speech Tokens

    PubMed Central

    Cone, Barbara; Whitaker, Richard

    2013-01-01

    Objectives Cortical auditory evoked potentials (CAEPs) to tones and speech sounds were obtained in infants to: 1) further knowledge of auditory development above the level of the brainstem during the first year of life; 2) establish CAEP input-output functions for tonal and speech stimuli as a function of stimulus level and to 3) elaborate the data-base that establishes CAEP in infants tested while awake using clinically relevant stimuli, thus providing methodology that would have translation to pediatric audiological assessment. Hypotheses concerning CAEP development were that the latency and amplitude input-output functions would reflect immaturity in encoding stimulus level. In a second experiment, infants were tested with the same stimuli used to evoke the CAEPs. Thresholds for these stimuli were determined using observer-based psychophysical techniques. The hypothesis was that the behavioral thresholds would be correlated with CAEP input-output functions because of shared cortical response areas known to be active in sound detection. Design 36 infants, between the ages of 4-12 months (mean= 8 months, s.d.=1.8 months) and 9 young adults (mean age 21 years) with normal hearing were tested. First, CAEPs amplitude and latency input-output functions were obtained for 4 tone bursts and 7 speech tokens. The tone bursts stimuli were 50 ms tokens of pure tones at 0.5, 1.0, 2.0 and 4.0 kHz. The speech sound tokens, /a/, /i/, /o/, /u/, /m/, /s/, and /?/, were created from natural speech samples and were also 50 ms in duration. CAEPs were obtained for tone burst and speech token stimuli at 10 dB level decrements in descending order from 70 dB SPL. All CAEP tests were completed while the infants were awake and engaged in quiet play. For the second experiment, observer-based psychophysical methods were used to establish perceptual threshold for the same speech sound and tone tokens. Results Infant CAEP component latencies were prolonged by 100-150 ms in comparison to adults. CAEP latency-intensity input output functions were steeper in infants compared to adults. CAEP amplitude growth functions with respect to stimulus SPL are adult-like at this age, particularly for the earliest component, P1-N1. Infant perceptual thresholds were elevated with respect to those found in adults. Furthermore, perceptual thresholds were higher, on average, than levels at which CAEPs could be obtained. When CAEP amplitudes were plotted with respect to perceptual threshold (dB SL), the infant CAEP amplitude growth slopes were steeper than in adults. Conclusions Although CAEP latencies indicate immaturity in neural transmission at the level of the cortex, amplitude growth with respect to stimulus SPL is adult-like at this age, particularly for the earliest component, P1-N1. The latency and amplitude input-output functions may provide additional information as to how infants perceive stimulus level. The reasons for the discrepancy between electrophysiologic and perceptual threshold may be due to immaturity in perceptual temporal resolution abilities and the broad-band listening strategy employed by infants. The findings from the current study can be translated to the clinical setting. It is possible to use tonal or speech sound tokens to evoke CAEPs in an awake, passively alert infant, and thus determine whether these sounds activate the auditory cortex. This could be beneficial in the verification of hearing aid or cochlear implant benefit. PMID:23722003

  15. NLP-12 engages different UNC-13 proteins to potentiate tonic and evoked release.

    PubMed

    Hu, Zhitao; Vashlishan-Murray, Amy B; Kaplan, Joshua M

    2015-01-21

    A neuropeptide (NLP-12) and its receptor (CKR-2) potentiate tonic and evoked ACh release at Caenorhabditis elegans neuromuscular junctions. Increased evoked release is mediated by a presynaptic pathway (egl-30 G?q and egl-8 PLC?) that produces DAG, and by DAG binding to short and long UNC-13 proteins. Potentiation of tonic ACh release persists in mutants deficient for egl-30 G?q and egl-8 PLC? and requires DAG binding to UNC-13L (but not UNC-13S). Thus, NLP-12 adjusts tonic and evoked release by distinct mechanisms. PMID:25609620

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

    EPA Science Inventory

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

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

    EPA Science Inventory

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

  18. Facilitation of cortically evoked potentials with motor imagery during post-exercise depression of corticospinal excitability

    Microsoft Academic Search

    Julia B. Pitcher; Alexandra L. Robertson; Emma C. Clover; Shapour Jaberzadeh

    2005-01-01

    This study examined whether muscle fatigue alters the facilitatory effect of motor imagery on corticospinal excitability. We aimed to determine if post-exercise depression of potentials evoked magnetically from the motor cortex is associated with alterations in internally generated movement plans. In experiment 1, motor-evoked potentials (MEPs) were recorded from two right hand and two right forearm muscles, at rest and during

  19. Visual evoked potentials in Negro carriers of the gene for tyrosinase positive oculocutaneous albinism.

    PubMed

    Castle, D; Kromberg, J; Kowalsky, R; Moosa, R; Gillman, N; Zwane, E; Fritz, V

    1988-12-01

    Visual evoked potential testing was performed on 15 Negro carriers of the gene for tyrosinase positive oculocutaneous albinism in order to detect whether they have the same visual pathway decussation anomalies as do homozygotes. No subject showed 01-02 asymmetry on monocular testing, indicating that decussation follows the normal pattern. It is concluded that visual evoked potential testing is probably not useful in the detection of Negroes heterozygous for the gene for tyrosinase positive oculocutaneous albinism. PMID:3148727

  20. Visual evoked potentials in Negro carriers of the gene for tyrosinase positive oculocutaneous albinism.

    PubMed Central

    Castle, D; Kromberg, J; Kowalsky, R; Moosa, R; Gillman, N; Zwane, E; Fritz, V

    1988-01-01

    Visual evoked potential testing was performed on 15 Negro carriers of the gene for tyrosinase positive oculocutaneous albinism in order to detect whether they have the same visual pathway decussation anomalies as do homozygotes. No subject showed 01-02 asymmetry on monocular testing, indicating that decussation follows the normal pattern. It is concluded that visual evoked potential testing is probably not useful in the detection of Negroes heterozygous for the gene for tyrosinase positive oculocutaneous albinism. PMID:3148727

  1. Changes in visual-evoked potential habituation induced by hyperventilation in migraine

    Microsoft Academic Search

    Gianluca Coppola; Antonio Currà; Simona Liliana Sava; Alessia Alibardi; Vincenzo Parisi; Francesco Pierelli; Jean Schoenen

    2010-01-01

    Hyperventilation is often associated with stress, an established trigger factor for migraine. Between attacks, migraine is\\u000a associated with a deficit in habituation to visual-evoked potentials (VEP) that worsens just before the attack. Hyperventilation\\u000a slows electroencephalographic (EEG) activity and decreases the functional response in the occipital cortex during visual stimulation.\\u000a The neural mechanisms underlying deficient-evoked potential habituation in migraineurs remain unclear.

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

    E-print Network

    Randolph, William Robert

    1984-01-01

    ATTEMPTS TO ELICIT AN EVOKED POTENTIAL IN THE PIGEON USING A MAGNETIC FIELD STIMULUS A Thesis by WILLIAM ROBERT RANDOLPH Submitted to the Graduate College of Texas A&M University in partial fulfillment of the requirements for the degree... of MASTER OF SCIENCE December 19B4 Major Subject: Bioengineering ATTEMPTS TO ELICIT AN EVOKED POTENTIAL IN THE PIGEON USING A MAGNETIC FIELD STIMULUS A Thesis by WILLIAM ROBERT RANDOLPH ( Approved as to style and content by: Jon F. Hunter (Chairma...

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

    PubMed

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

    2011-02-01

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

  4. What do evoked potentials tell us about the acoustic system of the harbor porpoise?

    NASA Astrophysics Data System (ADS)

    Bibikov, N. G.

    2004-05-01

    The evoked acoustic potentials of the brainstem (EAPB) were detected from the brain, the skull, and the surface of the head of the harbor porpoise ( Phocaena phocaena). Experiments were performed at the Karadag biological station (Crimea). Clicks, noise, and tone bursts of different frequencies within 80 190 kHz were used as stimuli. The time and frequency selectivities of the auditory system were estimated by the simultaneous and direct forward masking methods. The minima of EAPB thresholds were usually observed in a frequency range of 120 140 kHz, which corresponded to the main spectral maximum of the species-specific echolocation signal. In addition to the regular EAPB, a pronounced off-EAPB was observed. In the aforementioned frequency range, a frequency selectivity ( Q 10 of about 10) was revealed by the direct forward masking method. The EAPB could be measured up to a frequency of 190 kHz, but outside this high-resolution region (outside the ultrasonic “fovea”), the frequency selectivity was weak. A simultaneous masking of a click by a tone was strong only when the delay of the click with respect to the masker onset was smaller than 1.0 ms. In a continuous regime, the tone (unlike noise) produced only a weak masking. The response to a small intensity increment of 1 4 dB was rather strong. In the frequency range of 120 140 kHz, this response exhibited a nonmonotone dependence on the signal level. The time resolving power, which was measured by the EAPB recovery functions for double clicks of various levels, was rather high, even when the intensity of the test signal was 18 dB lower than the masker level. Experimental data show that the auditory system of the harbor porpoise is tuned to detecting ultrasonic echo signals in the frequency range within 120 140 kHz. A hypothesis is put forward that the acoustic system of the harbor porpoise allows the animal, from analyzing echo signals, to estimate not only the distance to the target and the target’s intrinsic properties but also the speed with which the target is approached, the latter estimate being presumably obtained on the basis of the Doppler effect.

  5. Flash, somatosensory-, and peripheral nerve-evoked potentials in rats perinatally exposed to Aroclor 1254

    Microsoft Academic Search

    David W Herr; Jaimie E Graff; Ethel C Derr-Yellin; Kevin M Crofton; Prasada R. S Kodavanti

    2001-01-01

    Pregnant Long–Evans rats were exposed to 0, 1 or 6 mg\\/kg\\/day of Aroclor 1254 (A1254; Lot no. 124-191), a commercial mixture of polychlorinated biphenyls (PCBs), from gestation day (GD) 6 through postnatal day (PND) 21. At 128–140 days of age, male and female offspring were tested for visual-, somatosensory- and peripheral nerve-evoked potentials. The evoked responses increased in amplitude with

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

    NASA Technical Reports Server (NTRS)

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

    1975-01-01

    Results of vertex-evoked potential studies conducted to determine how decision confidence level and decision probability interact to determine P3 amplitude for both signal-present and signal-absent decisions. They support the contention that the form of the vertex-evoked response is closely correlated with the subject's psychophysical response regarding the presence or absence of a threshold-level signal.

  7. Computer Processing of Visual Evoked Potentials Utilizing Digital Filtering Techniques

    PubMed Central

    Vigorito, A.; Stephens, G.; Louis, H.; Cinotti, A.; Michelson, L.; Stephens, E.

    1981-01-01

    Recording of the VER (Visual Evoked Response) and the ERG (ElectroRetinoGram) in our laboratory is done with stimulation, using a fixed checkerboard pattern or a reversible checkerboard pattern. Questionable data frames are eliminated from the signal averaging process by means of a semiautomatic electronic analyzer or by means of a computer program. This special computer software, with flexible format constraints, is utilized on an off-line basis to remove residual artifacts and noise from averaged data by means of generalized lowpass, highpass, bandpass, and/or bandstop digital filtering, conforming to user-specified cutoff frequencies and rolloff. ERG's and VER's of neurologic and ophthalmologic cases are presented in order to illustrate the advantages of this system in clinical diagnosis and evaluation.

  8. Monitoring somatosensory evoked potentials in spinal cord ischemia-reperfusion injury

    PubMed Central

    Ji, Yiming; Meng, Bin; Yuan, Chenxi; Yang, Huilin; Zou, Jun

    2013-01-01

    It remains unclear whether spinal cord ischemia-reperfusion injury caused by ischemia and other non-mechanical factors can be monitored by somatosensory evoked potentials. Therefore, we monitored spinal cord ischemia-reperfusion injury in rabbits using somatosensory evoked potential detection technology. The results showed that the somatosensory evoked potential latency was significantly prolonged and the amplitude significantly reduced until it disappeared during the period of spinal cord ischemia. After reperfusion for 30–180 minutes, the amplitude and latency began to gradually recover; at 360 minutes of reperfusion, the latency showed no significant difference compared with the pre-ischemic value, while the somatosensory evoked potential amplitude in-creased, and severe hindlimb motor dysfunctions were detected. Experimental findings suggest that changes in somatosensory evoked potential latency can reflect the degree of spinal cord ischemic injury, while the amplitude variations are indicators of the late spinal cord reperfusion injury, which provide evidence for the assessment of limb motor function and avoid iatrogenic spinal cord injury. PMID:25206629

  9. Somatosensory evoked potentials with a unilateral migration disorder of the cerebrum.

    PubMed

    Ozawa, H; Inagaki, M; Aikoh, H; Hanaoka, S; Sugai, K; Hashimoto, T; Kaga, M

    1998-05-01

    The somatosensory evoked potentials in two children with a unilateral migration disorder (pachygyria) of the cerebrum, which was detected by MRI, were examined in order to evaluate the function of the malformed sensory cortex. A 5-year-old girl had slight left hemiparesis, seizures, and mental retardation, and a 4-month-old boy had left hemiparesis. Neither patient showed distinct sensory disturbance. Short latency somatosensory evoked potentials and somatosensory evoked potentials recordings demonstrated that the early cortical component, N20, was absent and a positive wave appeared on paretic left-hand stimulation. On nonparetic right-hand stimulation, the primary evoked response (N20-P30) of the left hemisphere, which originates in Broadmann area 3b, was almost normal. Multichannel recordings on the scalp of one patient revealed that a positive wave without polarity inversion appeared posterior to the right central sulcus on median nerve stimulation on the paretic side. The radial dipole in the sensory cortex (area 1 or area 3a) or motor cortex (area 4) could have formed the positive/negative biphasic wave in the relatively wide centroparietal area in the present patients. In the case of unilateral cortical dysplasia, the malformed cortex with subnormal function of sensation might induce the change in the early component of somatosensory evoked potentials. PMID:9620011

  10. An indirect component in the evoked compound action potential of the vagal nerve

    NASA Astrophysics Data System (ADS)

    Ordelman, Simone C. M. A.; Kornet, Lilian; Cornelussen, Richard; Buschman, Hendrik P. J.; Veltink, Peter H.

    2010-12-01

    The vagal nerve plays a vital role in the regulation of the cardiovascular system. It not only regulates the heart but also sends sensory information from the heart back to the brain. We hypothesize that the evoked vagal nerve compound action potential contains components that are indirect via the brain stem or coming via the neural network on the heart. In an experimental study of 15 pigs, we identified four components in the evoked compound action potentials. The fourth component was found to be an indirect component, which came from the periphery. The latency of the indirect component increased when heart rate and contractility were decreased by burst stimulation (P = 0.01; n = 7). When heart rate and contractility were increased by dobutamine administration, the latency of the indirect component decreased (P = 0.01; n = 9). This showed that the latency of the indirect component of the evoked compound action potentials may relate to the state of the cardiovascular system.

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

    NASA Technical Reports Server (NTRS)

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

    1974-01-01

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

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

    PubMed

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

    2014-06-11

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

  13. Differing response properties of cervical and ocular vestibular evoked myogenic potentials evoked by air-conducted stimulation

    PubMed Central

    Dennis, Danielle L.; Govender, Sendhil; Chen, Peggy; Todd, Neil P. McAngus; Colebatch, James G.

    2014-01-01

    Objective To determine the amplitude changes of vestibular evoked myogenic potentials (VEMPs) recorded simultaneously from the neck (cVEMPs) and eyes (oVEMPs) in response to 500 Hz, 2 ms air-conducted sound pips over a 30 dB range. Methods Fifteen healthy volunteers (mean age 29, range 18–57 years old) and one patient with unilateral superior canal dehiscence (SCD) were studied. The stimulus was reduced in increments to 105 dB pSPL for the normals (81 dB pSPL for the SCD patient). A statistical criterion was used to detect responses. Results Ipsilateral (i-p13/n23) and contralateral (c-n12/p24/n30) peaks for the cVEMP montage and contralateral (c-n10/p16/n21) and ipsilateral (i-n13) peaks for the oVEMP montage were present for the baseline intensity. For the lowest intensity, 6/15 subjects had responses for the i-p13 cVEMP potential and 4/15 had c-n10 oVEMP responses. The SCD patient showed larger responses for nearly all intensities. The cVEMP potentials were generally well fitted by a power law relationship, but the oVEMP c-n10, p16 and n21 potentials showed a significant increase in gradient for the higher intensities. Conclusion Most oVEMP and cVEMP responses follow a power law relationship but crossed oVEMP responses showed a change in gradient above a threshold. Significance The pattern of response to AC stimulation may be a property of the pathways underlying the potentials. PMID:24290850

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

    ERIC Educational Resources Information Center

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

    2010-01-01

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

  15. Specificity and functional impact of post-exercise depression of cortically evoked motor potentials in man

    Microsoft Academic Search

    A. T. Humphry; E. J. Lloyd-Davies; R. J. Teare; K. E. Williams; P. H. Strutton; N. J. Davey

    2004-01-01

    Magnetic stimulation of the motor cortex with electromyographic recordings from exercising muscles has shown corticospinal excitability to be depressed following exercise. We now investigate whether this depression spreads to non-exercising muscles and its influence on performance. Healthy volunteers made unilateral biceps curls to exhaustion and, in another later session, for 25% of the time to exhaustion. Bilateral motor-evoked potentials (MEPs)

  16. Evoked Potential Audiograms of the Nurse Shark ( Ginglymostoma cirratum ) and the Yellow Stingray ( Urobatis jamaicensis )

    Microsoft Academic Search

    Brandon M. Casper; David A. Mann

    2006-01-01

    The hearing thresholds of the nurse shark, Ginglymostoma cirratum, and the yellow stingray, Urobatis jamaicensis, were measured using auditory evoked potentials (AEP). Stimuli were calibrated using a pressure-velocity probe so that the acoustic field could be completely characterized. The results show similar hearing thresholds for both species and similar hearing thresholds to previously measured audiograms for the lemon shark, Negaprion

  17. Feasibility and performance evaluation of generating and recording visual evoked potentials using ambulatory Bluetooth based system.

    PubMed

    Ellingson, Roger M; Oken, Barry

    2010-01-01

    Report contains the design overview and key performance measurements demonstrating the feasibility of generating and recording ambulatory visual stimulus evoked potentials using the previously reported custom Complementary and Alternative Medicine physiologic data collection and monitoring system, CAMAS. The methods used to generate visual stimuli on a PDA device and the design of an optical coupling device to convert the display to an electrical waveform which is recorded by the CAMAS base unit are presented. The optical sensor signal, synchronized to the visual stimulus emulates the brain's synchronized EEG signal input to CAMAS normally reviewed for the evoked potential response. Most importantly, the PDA also sends a marker message over the wireless Bluetooth connection to the CAMAS base unit synchronized to the visual stimulus which is the critical averaging reference component to obtain VEP results. Results show the variance in the latency of the wireless marker messaging link is consistent enough to support the generation and recording of visual evoked potentials. The averaged sensor waveforms at multiple CPU speeds are presented and demonstrate suitability of the Bluetooth interface for portable ambulatory visual evoked potential implementation on our CAMAS platform. PMID:21095851

  18. A software system for recording and analyzing transient evoked potential data with an Apple IIe computer

    Microsoft Academic Search

    John A. Baro; Stephen Lehmkuhle

    1988-01-01

    The software package described here was designed to digitize transient evoked potential data from two chan­ nels simultaneously and to analyze the data using an Apple fie computerand a relatively inexpensive hardware configuration. Individual modules provide several data collection paradigms, a number of data analyses, and dis­ play capabilities. The system is capable of accommodat­ ing a variety of hardware

  19. Intrarectal ground electrode improves the reliability of motor evoked potentials recorded in the anal sphincter.

    PubMed

    Lefaucheur, Jean-Pascal

    2005-07-01

    Motor evoked potentials (MEPs) can be recorded in the external anal sphincter in response to magnetic stimulation of the cerebral cortex or sacral roots. However, the magnitude of the stimulus artifact may alter the reliability of anal MEP recording. An intrarectal ground electrode substantially reduces stimulus artifact and technical failure, improving MEP latency determination to sacral root stimulation in particular. PMID:15880519

  20. MONOAMINE OXIDASE INHIBITION CANNOT ACCOUNT FOR CHANGES IN VISUAL EVOKED POTENTIALS PRODUCED BY CHLORDIMEFORM

    EPA Science Inventory

    Chlordimeform (CDM), a formamidine insecticide and monoamine oxidase (MAO) inhibitor, has recently been shown to produce profound changes in visual evoked potentials of hooded rats (Dyer and Boyes, The Toxicologist, 3: 13, 1983). Two experiments were performed to determine if the...

  1. Alteration of the visual evoked potential by macular holes: Comparison with optic neuritis

    Microsoft Academic Search

    L. N. Johnson; R. D. Yee; R. S. Hepler; D. A. Martin

    1987-01-01

    Nine patients with maculopathy (macular holes, macular cysts, and lamellar holes) and ten patients with optic neuritis were examined in order to determine changes in the visual evoked potential (VEP) in response to pattern-reversal stimulation. Eyes with lamellar holes had normal P100 latency, but eyes with macular cysts and macular holes had prolonged P100 latency. Eyes with optic neuritis exhibited

  2. Research on Brain-Computer Interface Technology Based on Steady State Visual Evoked Potentials

    Microsoft Academic Search

    Yan Bian; Li Zhao; Hongwei Li; Genghuang Yang; Hui Shen; Qingguo Meng

    2010-01-01

    A Brain-Computer Interface (BCI) system based on Steady State Visual Evoked Potentials (SSVEP) was presented in this paper to realize four-direction motion control of a small ball on the computer screen. The system mainly included five parts of visual stimulator, electroencephalogram (EEG) amplifier, EEG acquisition, EEG processing and machine human interface on the computer screen. The system utilized wavelet packet

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

    ERIC Educational Resources Information Center

    Bates, Tim; And Others

    1995-01-01

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

  4. A Steady State Visually Evoked Potential Investigation of Memory and Ageing

    ERIC Educational Resources Information Center

    Macpherson, Helen; Pipingas, Andrew; Silberstein, Richard

    2009-01-01

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

  5. Somatosensory evoked potentials for prediction of outcome in acute severe brain injury

    Microsoft Academic Search

    J. Beca; P. N. Cox; M. J. Taylor; D. Bohn; W. Butt; W. J. Logan; J. T. Rutka; G. Barker

    1995-01-01

    The purpose of this study was to evaluate prospectively short-latency somatosensory evoked potentials (SEPs) as a predictor of outcome in acute, severe brain injury, and to compare this with the predictive power of the motor component of the Glasgow Coma Scale score and computed tomographic scan. Outcome was measured with the Glasgow Outcome Scale at a minimum of 6 months

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

    EPA Science Inventory

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

  7. Deficits in the visual evoked potentials of cats as a result of visual deprivation

    Microsoft Academic Search

    A. Snyder; R. Shapley

    1979-01-01

    Summary Visual evoked potentials in response to contrast reversal of grating patterns were used as a measure of visual function in normal and visually deprived cats. In cats which had been dark reared from birth (BD cats) there was a characteristic change in VEP waveform from normal, for both eyes and for all spatial frequencies of testing stimulus. In cats

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

    EPA Science Inventory

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

  9. TEMPERATURE-DEPENDENT CHANGES IN VISUAL EVOKED POTENTIALS OF RATS (JOURNAL VERSION)

    EPA Science Inventory

    The effects of alterations in body temperature on flash and pattern reversal evoked potential (FEPs and PREPs) were examined in hooded rats whose thermoregulatory capacity was compromised with lesions of the preoptic/anterior hypothalamic area and/or cold restraint. Body temperat...

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

    EPA Science Inventory

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

  11. Neurotoxicity of antitumoral IL2 therapy: Evoked cognitive potentials and brain mapping

    Microsoft Academic Search

    A. Pace; A. Pietrangeli; L. Bove; M. Rosselli; M. Lopez; B. Jandolo

    1994-01-01

    Antitumoral interleukin-2 (IL-2) therapy is frequently associated with a neurotoxicity that manifests itself in neuropsychiatric disturbances and, more rarely, with neurological focal signs. With the aim of documenting the involvement of cognitive functions after IL-2 treatment, we studied 20 patients using evoked cognitive potentials (P300) and computer analysis of the EEG signal. A comparison of the tests performed before and

  12. Somatosensory evoked potential from S1 nerve root stimulation

    Microsoft Academic Search

    Xiao-Dong Wu; Yu Zhu; Wen-Jun Chen; Xiang Jin; Nicholas Tsai; Huang-Yuan Huang; Jian-Yuan Jiang; Dong-Qing Zhu; Pei-Ying Li; Robert Weber; Wen Yuan; Hua-Jiang Chen

    The objective of this study was to detect cerebral potentials elicited by proximal stimulation of the first sacral (S1) nerve\\u000a root at the S1 dorsal foramen and to investigate latency and amplitude of the first cerebral potential. Tibial nerve SEP and\\u000a S1 nerve root SEP were obtained from 20 healthy subjects and 5 patients with unilateral sciatic nerve or tibial

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

    EPA Science Inventory

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

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

    EPA Science Inventory

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

  15. Pharmacological characterization of postsynaptic potentials evoked in the bimodal pacemaker neuron of Helix pomatia L.

    PubMed

    Vehovszky, A; Salánki, J

    1983-01-01

    Stimulation of various peripheral nerve trunks evokes very similar compound postsynaptic potentials (PSP) composed of one or more excitatory postsynaptic potentials (EPSP) followed by fast and slow inhibitory postsynaptic potentials (IPSP) on the identified RPal neuron of Helix pomatia L. Evoked EPSPs were reduced or blocked by nicotine, atropine and d-tubocurarine. The two components of IPSP were different in their pharmacological sensitivity. Slow IPSP was partly or totally eliminated by ergometrine and chlorpromazine and was reduced by atropine, nicotine as well as by propranolol. Fast IPSP was reduced only in the presence of ergometrine and could not be blocked by either of the applied drugs. Participation of cholinergic transmission seems to be essential in the evoked EPSP but its partial involvement in the slow IPSP can also be supposed. A dopaminergic mechanism may take part in the generation of both components of IPSP but the receptors responsible for the slow IPSP were sensitive to other catecholamine antagonists as well, referring to a more complex origin, or to the involvement of an unknown transmitter. Comparison of PSPs evoked by stimulation of different nerves shows that presynaptic areas belonging to various peripheral sources are overlapped on the RPal neuron, and they probably act by similar transmitter substances. PMID:6650194

  16. Research on the effectiveness of intermittent cervical traction therapy, using short-latency somatosensory evoked potentials

    Microsoft Academic Search

    Mikihiko Hattori; Yasumasa Shirai; Takafumi Aoki

    2002-01-01

    .   Short-latency somatosensory evoked potentials (SSEPs) were measured before and after intermittent cervical traction therapy\\u000a to serve as objective indicators of therapy effectiveness. The subjects were 29 patients with myelopathy, 23 with cervical\\u000a radiculopathy, 28 with cervical sprain, and 26 healthy individuals. SSEPs were recorded by stimulating the median nerve, and\\u000a the negative potentials elicited from the brachial plexus (N9),

  17. Generators of visual evoked potentials investigated by dipole tracing in the human occipital cortex

    Microsoft Academic Search

    H Ikeda; H Nishijo; K Miyamoto; R Tamura; S Endo; T Ono

    1998-01-01

    Current source generators (dipoles) of the human visual evoked potentials to pattern-onset stimuli were investigated with the dipole tracing method, using a realistic four-layer head model of scalp-skull-fluid-brain, which can equate the surface potential distributions on a scalp to one or two corresponding equivalent dipoles. Three healthy adult human subjects were used, and 29 electrodes were set on a scalp

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

    NASA Technical Reports Server (NTRS)

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

    1975-01-01

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

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

    PubMed Central

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

    2014-01-01

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

  20. The use of evoked potentials in sleep research.

    PubMed

    Colrain, Ian M; Campbell, Kenneth B

    2007-08-01

    Averaged event-related potentials (ERPs) represent sensory and cognitive processing of stimuli during wakefulness independent of behavioral responses, and reflect the underlying state of the CNS (central nervous system) during sleep. Components measured during wakefulness which are reflective of arousal state or the automatic switching of attention are sensitive to prior sleep disruption. Components reflecting active attentional influences during the waking state appear to be preserved in a rudimentary form during REM sleep, but in a way that highlights the differences in the neurochemical environment between wakefulness and REM sleep. Certain ERP components only appear within sleep. These begin to emerge at NREM sleep onset and may reflect inhibition of information processing and thus have utility as markers of the functional status of sleep preparatory mechanisms. These large amplitude NREM components represent synchronized burst firing of large number of cortical cells and are a reflection of the nervous system's capacity to generate delta frequency EEG activity. As such they are useful in assessing the overall integrity of the nervous system in populations not showing substantial amounts of SWS as measured using traditional criteria. While requiring care in their interpretation, ERPs nonetheless provide a rich tool to investigators interested in probing the nervous system to evaluate daytime functioning in the face of sleep disruption, the ability of the sleeping nervous system to monitor the external environment, and the ability of the nervous system to respond to stimuli in a manner consistent with the initiation or maintenance of sleep. PMID:17628317

  1. 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

  2. Why do stroke patients with negative motor evoked potential show poor limb motor function recovery?

    PubMed Central

    Song, Zhibin; Dang, Lijuan; Zhou, Yanling; Dong, Yanjiang; Liang, Haimao; Zhu, Zhengfeng; Pan, Suyue

    2013-01-01

    Negative motor evoked potentials after cerebral infarction, indicative of poor recovery of limb motor function, tend to be accompanied by changes in fractional anisotropy values and the cerebral peduncle area on the affected side, but the characteristics of these changes have not been reported. This study included 57 cases of cerebral infarction whose motor evoked potentials were tested in the 24 hours after the first inspection for diffusion tensor imaging, in which 29 cases were in the negative group and 28 cases in the positive group. Twenty-nine patients with negative motor evoked potentials were divided into two groups according to fractional anisotropy on the affected side of the cerebral peduncle: a fractional anisotropy < 0.36 group and a fractional anisotropy ? 0.36 group. All patients underwent a regular magnetic resonance imaging and a diffusion tensor imaging examination at 1 week, 1, 3, 6 and 12 months after cerebral infarction. The Fugl-Meyer scores of their hemiplegic limbs were tested before the magnetic resonance and diffusion tensor imaging tions. In the negative motor evoked potential group, fractional anisotropy in the affected cerebral peduncle declined progressively, which was most obvious in the first 1–3 months after the onset of cerebral infarction. The areas and area asymmetries of the cerebral peduncle on the affected side were significantly decreased at 6 and 12 months after onset. At 12 months after onset, the area asymmetries of the cerebral peduncle on the affected side were lower than the normal lower limit value of 0.83. Fugl-Meyer scores in the fractional anisotropy ? 0.36 group were significantly higher than in the fractional anisotropy < 0.36 group at 3–12 months after onset. The fractional anisotropy of the cerebral peduncle in the positive motor evoked potential group decreased in the first 1 month after onset, and stayed unchanged from 3–12 months; there was no change in the area of the cerebral peduncle in the first 1–12 months after cerebral infarction. These findings confirmed that if the fractional anisotropy of the cerebral peduncle on the affected side is < 0.36 and the area asymmetries < 0.83 in patients with negative motor evoked potential after cerebral infarction, then poor hemiplegic limb motor function recovery may occur. PMID:25206582

  3. Methylene blue potentiates stimulus-evoked fMRI responses and cerebral oxygen consumption during normoxia and hypoxia

    E-print Network

    Duong, Timothy Q.

    Methylene blue potentiates stimulus-evoked fMRI responses and cerebral oxygen consumption during Forepaw stimulation Methylene blue USP (MB) at low doses has metabolic-enhancing and antioxidant effects on cerebral blood flow (CBF), functional evoked responses, and the associated changes in cerebral

  4. BODY TEMPERATURE-DEPENDENT AND INDEPENDENT ACTIONS OF CHLORDIMEFORM ON VISUAL EVOKED POTENTIALS AND AXONAL TRANSPORT IN OPTIC SYSTEM OF RAT

    EPA Science Inventory

    Pattern reversal evoked potentials (PREPs), flash evoked potentials (FEPs), optic nerve axonal transport, and body temperature were measured in hooded rats treated with either saline or the formamidine insecticide/acaricide, chlordimeform (CDM). Rats receiving CDM had low body te...

  5. Fast Detection of Unexpected Sound Intensity Decrements as Revealed by Human Evoked Potentials

    PubMed Central

    Althen, Heike; Grimm, Sabine; Escera, Carles

    2011-01-01

    The detection of deviant sounds is a crucial function of the auditory system and is reflected by the automatically elicited mismatch negativity (MMN), an auditory evoked potential at 100 to 250 ms from stimulus onset. It has recently been shown that rarely occurring frequency and location deviants in an oddball paradigm trigger a more negative response than standard sounds at very early latencies in the middle latency response of the human auditory evoked potential. This fast and early ability of the auditory system is corroborated by the finding of neurons in the animal auditory cortex and subcortical structures, which restore their adapted responsiveness to standard sounds, when a rare change in a sound feature occurs. In this study, we investigated whether the detection of intensity deviants is also reflected at shorter latencies than those of the MMN. Auditory evoked potentials in response to click sounds were analyzed regarding the auditory brain stem response, the middle latency response (MLR) and the MMN. Rare stimuli with a lower intensity level than standard stimuli elicited (in addition to an MMN) a more negative potential in the MLR at the transition from the Na to the Pa component at circa 24 ms from stimulus onset. This finding, together with the studies about frequency and location changes, suggests that the early automatic detection of deviant sounds in an oddball paradigm is a general property of the auditory system. PMID:22163029

  6. Vestibular evoked potentials (VsEPs) of cortical origin produced by impulsive acceleration applied at the nasion.

    PubMed

    Todd, Neil P M; McLean, Aisha; Paillard, Aurore; Kluk, Karolina; Colebatch, James G

    2014-12-01

    We report the results of a study to record vestibular evoked potentials (VsEPs) of cortical origin produced by impulsive acceleration (IA). In a sample of 12 healthy participants, evoked potentials recorded by 70 channel electroencephalography were obtained by IA stimulation at the nasion and compared with evoked potentials from the same stimulus applied to the forefingers. The nasion stimulation gave rise to a series of positive and negative deflections in the latency range of 26-72 ms, which were dependent on the polarity of the applied IA. In contrast, evoked potentials from the fingers were characterised by a single N50/P50 deflection at about 50 ms and were polarity invariant. Source analysis confirmed that the finger evoked potentials were somatosensory in origin, i.e. were somatosensory evoked potentials, and suggested that the nasion evoked potentials plausibly included vestibular midline and frontal sources, as well as contributions from the eyes, and thus were likely VsEPs. These results show considerable promise as a new method for assessment of the central vestibular system by means of VsEPs produced by IA applied to the head. PMID:25138912

  7. Characteristics of brain stem auditory evoked potentials in children with hearing impairment due to infectious diseases.

    PubMed

    Je?menica, Jovana Radovan; Opan?ina, Aleksandra Aleksandar Bajec

    2015-05-01

    Among objective audiologic tests, the most important were tests of brain stem auditory evoked potentials. The objective of the study was to test the configuration, degree of hearing loss, and response characteristics of auditory brain stem evoked potentials in children with hearing loss occurred due to infectious disease. A case control study design was used. The study group consisted of 54 patients referred for a hearing test because of infectious diseases caused by other agents or that occurred as congenital infection. Infectious agents have led to the emergence of various forms of sensorineural hearing loss. We have found deviations from the normal values of absolute and interwave latencies in some children in our group. We found that in the group of children who had the diseases such as purulent meningitis, or were born with rubella virus and cytomegalovirus infection, a retrocochlear damage was present in children with and without cochlear damage. PMID:24939973

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

    PubMed

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

    2013-11-25

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

  9. Comparison of five sedation scoring systems by means of auditory evoked potentials

    Microsoft Academic Search

    A. M. Schulte-Tamburen; J. Scheier; J. Briegel; D. Schwender; K. Peter

    1999-01-01

    Objective: To review five sedation scoring systems and to determine their correlation with an objective method for assessing the level\\u000a of sedation by means of auditory evoked potentials (AEP) in critically ill patients. Design: Prospective clinical study. Setting: Multidisciplinary intensive care unit in a university hospital. Patients: Ninety-five consecutive patients requiring sedation during intensive care therapy. Measurements and results: Previous

  10. Post-exercise depression of motor evoked potentials as a function of exercise duration

    Microsoft Academic Search

    Ali Samii; Eric M. Wassermann; Mark Hallett

    1997-01-01

    Post-exercise facilitation and post-exercise depression are phenomena described in motor evoked potentials (MEPs) elicited to transcranial magnetic stimulation. Brief, non-fatiguing muscle activation produces post-exercise facilitation, and prolonged fatiguing muscle activation produces post-exercise depression. We studied 12 normal subjects to determine whether post-exercise depression occurs before fatigue is reached. We recorded MEPs from the resting extensor carpi radialis muscle after increasing

  11. Absence of facilitation or depression of motor evoked potentials after contralateral homologous muscle activation

    Microsoft Academic Search

    Ali Samii; Michael Caños; Katsunori Ikoma; Eric M. Wassermann; Mark Hallett

    1997-01-01

    We have previously described post-exercise facilitation and post-exercise depression of motor evoked potentials (MEPs) to transcranial magnetic stimulation (TMS). To determine the presence of post-exercise facilitation after exercise of a contralateral muscle, MEPs were recorded from the resting right extensor carpi radialis (ECR) muscle while the left ECR muscle was activated, then immediately after brief left ECR activation, and, finally,

  12. Maturation of human central auditory system activity: evidence from multi-channel evoked potentials

    Microsoft Academic Search

    Curtis W. Ponton; Jos J. Eggermont; Betty Kwong; Manuel Don

    2000-01-01

    Objective: The purpose of this study was to evaluate central auditory system maturation based on detailed data from multi-electrode recordings of long-latency auditory evoked potentials (AEPs).Methods: AEPs were measured at 30 scalp-electrode locations from 118 subjects between 5 and 20 years of age. Analyses focused on age-related latency and amplitude changes in the P1, N1b, P2, and N2 peaks of

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

    Microsoft Academic Search

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

    2005-01-01

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

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

    Microsoft Academic Search

    Masafumi Fukuda; Makoto Oishi; Tetsuya Hiraishi; Yukihiko Fujii

    2010-01-01

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

  15. Abnormal Cortical Network Activation in Human Amnesia: A High-resolution Evoked Potential Study

    Microsoft Academic Search

    Sandra Barcellona-Lehmann; Stéphanie Morand; Claire Bindschaedler; Louis Nahum; Damien Gabriel; Armin Schnider

    2010-01-01

    Little is known about how human amnesia affects the activation of cortical networks during memory processing. In this study,\\u000a we recorded high-density evoked potentials in 12 healthy control subjects and 11 amnesic patients with various types of brain\\u000a damage affecting the medial temporal lobes, diencephalic structures, or both. Subjects performed a continuous recognition\\u000a task composed of meaningful designs. Using whole-scalp

  16. Visual evoked potentials in relation to factors of imprisonment in detention camps

    Microsoft Academic Search

    A. Vrca; V. Bozikov; Z. Brzovi?; R. Fuchs; M. Malinar

    1996-01-01

    Visual evoked potentials (VEPs) of the pattern shift reversal type were determined in a representative group of 57 prisoners of war (POWs) released in 1992 from detention camps in former Yugoslavia. The parameters were correlated with the conditions in four camps (1–4). All subjects were male, with a mean age of 34.75 years (SD ± 8.92), average length of imprisonment

  17. Cerebral potentials and electromyographic responses evoked by stretch of wrist muscles in man

    Microsoft Academic Search

    G. Abbruzzese; A. Berardelli; J. C. Rothwell; B. L. Day; C. D. Marsden

    1985-01-01

    Summary  The cerebral evoked potential produced by rapid extension of the wrist was recorded from scalp electrodes in normal subjects while they exerted a small background flexor torque (0.24 Nm) against an electric motor. The initial part of the response consisted of a negative deflection (N1) with an average latency of 24.7 ms. This was followed by a biphasic P1\\/P2 (32

  18. EEG alpha rhythms and transient chromatic and achromatic pattern visual evoked potentials in children and adults

    Microsoft Academic Search

    Mei Ying Boon; Kar Ying Chan; Jaclyn Chiang; Rebecca Milston; Catherine Suttle

    2011-01-01

    Transient chromatic pattern visual evoked potentials (VEPs) have been found to be less repeatable in morphology in children\\u000a than in adults at low to moderate chromatic contrasts. The purpose of this study is to investigate whether low repeatability\\u000a of VEP components can be associated with high alpha power, in a comparison of alpha activity in children and adults. Transient\\u000a chromatic

  19. Diurnal Periodicity of Lateral Asymmetries of the Visual Evoked Potential in Healthy Volunteers

    Microsoft Academic Search

    P. Zimmermann; R. Görtelmeyer; H. Wiemann

    1983-01-01

    Visual evoked potential (VEP) was analyzed in 24 healthy male volunteers (age: 25–35 years) between 7.00 a.m. and 4.00 p.m. to evaluate possible diurnal variation in hemispheric differences of the response to a diffuse or 1 ° flash and checkerboard pattern-reversal (stimulation: binocular). VEP was recorded over O2–A1 and O2–A2, and 64 exposures were averaged during each session. After diffuse

  20. Middle and long latency somatosensory evoked potentials after painful laser stimulation in patients with fibromyalgia syndrome

    Microsoft Academic Search

    J. Lorenz; K. Grasedyck; B. Bromm

    1996-01-01

    Ten femalespatients with fibromyalgia syndrome (FS) were investigated with laser evoked potentials (LEPs) after hand stimulations and compared with 10 female pain-free and age-matched control patients. FS patients exhibited significantly lower heat pain thresholds than controls (P < 0.05) and had higher amplitudes of LEP components N170 (P < 0.01) and P390 (P < 0.05) in response to intensities of

  1. Middle Latency Auditory Evoked Potential Anaesthesia Correlates of Consciousness: Practicality & Constraints

    Microsoft Academic Search

    D. Burton; Myles PS; I. Brown; M. Xu; E. Zilberg

    2005-01-01

    The hypothesis of this study is that significant differentiation of consciousness (CO) and unconsciousness (UNCO) is possible, using individual ML+AEP (10-140 msec) latency measures, within the context of a practical routine clinical depth of anaesthesia monitoring device. We have assessed individual latency band measures of the middle-latency auditory evoked potential (ML+AEP) as candidates to measure depth of CO or UNCO

  2. The effects of adult male mouse urine odor on evoked potentials in adult female mice

    E-print Network

    Brown, Troy Edwin

    1985-01-01

    data were collected from three mice for each stimulus (water, castrate mouse urine, and intact mouse urine) and subsequently analyzed. The power spectrum and coherence spectrum were used to locate and identify the odor evoked potentials. The results... Table I. Urine collected from each mouse II. Comparison of coherent frequencies Page 13 170 LIST OF FIGURES Figure Page Olfactometer Respiration pattern of anesthetized mouse 14 25 Power spectrum of computer generated 60 Hz sine waves 45...

  3. Development of the spatio-chromatic visual evoked potential (VEP): a longitudinal study

    Microsoft Academic Search

    M. A Crognale; J. P Kelly; A. H Weiss; D. Y Teller

    1998-01-01

    Most prior visual evoked potential (VEP) research on the development of color vision has employed pattern-reversing stimuli that are not optimal for producing chromatic responses. We measured infant VEPs using low spatial frequency, onset–offset stimuli, modulated along the three axes of a cone-based color space (Derrington et al. [J Physiol 1984;357, 241–265.]). Three color-normal infants were tested in a longitudinal

  4. Somatosensory evoked potential studies in internal capsule and corona radiata infarction

    Microsoft Academic Search

    J. Kalita; U. K. Misra

    1998-01-01

    To document the somatosensory evoked potential (SEP) changes in capsular and corona radiata infarction and correlate these\\u000a with clinical and radiological findings, 15 patients with corona radiata and 16 with internal capsular infarction were studied.\\u000a The mean age of the patients was 55 years (range 26–80), and 6 of them were female. In the patients with corona radiata infarction,\\u000a median

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

    PubMed Central

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

    2013-01-01

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

  6. An indirect component in the evoked compound action potential of the vagal nerve.

    PubMed

    Ordelman, Simone C M A; Kornet, Lilian; Cornelussen, Richard; Buschman, Hendrik P J; Veltink, Peter H

    2010-12-01

    The vagal nerve plays a vital role in the regulation of the cardiovascular system. It not only regulates the heart but also sends sensory information from the heart back to the brain. We hypothesize that the evoked vagal nerve compound action potential contains components that are indirect via the brain stem or coming via the neural network on the heart. In an experimental study of 15 pigs, we identified four components in the evoked compound action potentials. The fourth component was found to be an indirect component, which came from the periphery. The latency of the indirect component increased when heart rate and contractility were decreased by burst stimulation (P = 0.01; n = 7). When heart rate and contractility were increased by dobutamine administration, the latency of the indirect component decreased (P = 0.01; n = 9). This showed that the latency of the indirect component of the evoked compound action potentials may relate to the state of the cardiovascular system. PMID:20966537

  7. Lack of habituation of evoked visual potentials in analytic information processing style: evidence in healthy subjects.

    PubMed

    Buonfiglio, Marzia; Toscano, M; Puledda, F; Avanzini, G; Di Clemente, L; Di Sabato, F; Di Piero, V

    2015-03-01

    Habituation is considered one of the most basic mechanisms of learning. Habituation deficit to several sensory stimulations has been defined as a trait of migraine brain and also observed in other disorders. On the other hand, analytic information processing style is characterized by the habit of continually evaluating stimuli and it has been associated with migraine. We investigated a possible correlation between lack of habituation of evoked visual potentials and analytic cognitive style in healthy subjects. According to Sternberg-Wagner self-assessment inventory, 15 healthy volunteers (HV) with high analytic score and 15 HV with high global score were recruited. Both groups underwent visual evoked potentials recordings after psychological evaluation. We observed significant lack of habituation in analytical individuals compared to global group. In conclusion, a reduced habituation of visual evoked potentials has been observed in analytic subjects. Our results suggest that further research should be undertaken regarding the relationship between analytic cognitive style and lack of habituation in both physiological and pathophysiological conditions. PMID:25260654

  8. Visual evoked potentials for attentional gating in a brain-computer interface.

    PubMed

    Geronimo, Andrew; Schiff, Steven J; Kamrunnahar, Mst

    2012-01-01

    For synchronous brain-computer interface (BCI) paradigms tasks that utilize visual cues to direct the user, the neural signals extracted by the computer are representative of voluntary modulation as well as evoked responses. For these paradigms, the evoked potential is often overlooked as a source of artifact. In this paper, we put forth the hypothesis that cue priming, as a mechanism for attentional gating, is predictive of motor imagery performance, and thus a viable option for self-paced (asynchronous) BCI applications. We approximate attention by the amplitude features of visually evoked potentials (VEP)s found using two methods: trial matching to an average VEP template, and component matching to a VEP template defined using independent component analysis (ICA). Templates were used to rank trials that display high vs. low levels of fixation. Our results show that subject fixation, measured by VEP response, fails as a predictor of successful motor-imagery task completion. The implications for the BCI community and the possibilities for alternative cueing methods are given in the conclusions. PMID:23366247

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

    NASA Technical Reports Server (NTRS)

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

    1985-01-01

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

  10. Impairment of perinatal hypoxia–ischemia to the preterm brainstem

    Microsoft Academic Search

    Ze D. Jiang; Dorothea M. Brosi; C. Chen; Andrew R. Wilkinson

    2009-01-01

    Hypoxia–ischemia is a major perinatal problem that results in severe damage to the newborn brain. This study assessed functional integrity of the brainstem at term in preterm infants after perinatal hypoxia–ischemia to shed light on the influence of hypoxia–ischemia on the preterm brainstem. We recruited sixty-eight preterm infants after perinatal hypoxia–ischemia, ranging in gestation 28–35weeks. Brainstem evoked response was studied

  11. Fenvalerate induced changes in evoked potentials from the ventral nerve cord (VNC) of cockroach, Periplaneta americana.

    PubMed

    Venkatramana Reddy, A T; Yellamma, K

    1991-02-01

    Changes in evoked potentials from the VNC of P. americana were recorded under in vitro and topical application of sublethal doses of fenvalerate. In this study significant changes in physical characteristics of action potentials like threshold voltage, duration, latency and amplitude were noticed. In in vitro studies the effects were found to be dose dependent, while in topical exposure maximum effect was noticed at 3h, followed by recovery during subsequent periods of exposure. Moreover, changes were more pronounced in in vitro than topical exposure. PMID:1877986

  12. Epicranial sensory evoked potential recordings for repeated assessment of cortical functions in mice.

    PubMed

    Troncoso, E; Muller, D; Czellar, S; Zoltan Kiss, J

    2000-04-01

    In the present study, we describe a simple and minimally invasive method to record sensory evoked potentials (SEP) in the anesthetized mouse. The hardware includes a 16-channel acquisition system with a high signal/noise ratio and high temporal resolution. Under general anesthesia the skull is exposed and stainless steel electrodes are placed directly over the bone. A computer controlled electromechanical stimulation is applied to a single whisker or a group of whiskers unilaterally and cortical responses are recorded bilaterally. Primary SEP are detected over the contralateral barrel cortex, but delayed signals appear over the motor cortex, secondary somatosensory cortex and the ipsilateral hemisphere. The size of evoked SEP correlates with the number of stimulated whiskers and responses are reproducible and consistent over time when recorded repeatedly for up to 6 weeks. We conclude that epicranial multichannel recording of SEP represents an interesting, minimally invasive approach to monitor repeatedly cortical activity and study certain aspects of long-term plasticity of evoked responses in mice. PMID:10771075

  13. Noise-induced tinnitus: auditory evoked potential in symptomatic and asymptomatic patients

    PubMed Central

    dos Santos-Filha, Valdete Alves Valentins; Samelli, Alessandra Giannella; Matas, Carla Gentile

    2014-01-01

    OBJECTIVES: We evaluated the central auditory pathways in workers with noise-induced tinnitus with normal hearing thresholds, compared the auditory brainstem response results in groups with and without tinnitus and correlated the tinnitus location to the auditory brainstem response findings in individuals with a history of occupational noise exposure. METHOD: Sixty individuals participated in the study and the following procedures were performed: anamnesis, immittance measures, pure-tone air conduction thresholds at all frequencies between 0.25–8 kHz and auditory brainstem response. RESULTS: The mean auditory brainstem response latencies were lower in the Control group than in the Tinnitus group, but no significant differences between the groups were observed. Qualitative analysis showed more alterations in the lower brainstem in the Tinnitus group. The strongest relationship between tinnitus location and auditory brainstem response alterations was detected in individuals with bilateral tinnitus and bilateral auditory brainstem response alterations compared with patients with unilateral alterations. CONCLUSION: Our findings suggest the occurrence of a possible dysfunction in the central auditory nervous system (brainstem) in individuals with noise-induced tinnitus and a normal hearing threshold. PMID:25029581

  14. Task-specific role of ipsilateral pathways: somatosensory evoked potentials during cooperative hand movements.

    PubMed

    Schrafl-Altermatt, Miriam; Dietz, Volker

    2014-12-17

    Task-specific neural coupling during cooperative hand movements has been described in healthy volunteers, manifested by bilateral reflex electromyographic responses in forearm muscles following unilateral ulnar nerve stimulation and by task-specific activation of secondary somatosensory cortical areas (S2) in functional MRI. The aim of this study was to investigate the role of sensory input to the ipsilateral and contralateral cortex during a cooperative task. Somatosensory evoked potentials from the ulnar nerve were recorded over the ipsilateral and contralateral cortex during resting and during cooperative and noncooperative hand movements. Ipsilateral potentials with smaller amplitude were present under all conditions in almost all participants. In relation to the resting condition, the amplitudes of both the ipsilateral and the contralateral potential were reduced during the cooperative and the noncooperative tasks. Nevertheless, the reduction in amplitude was similar for the ipsilateral and the contralateral potentials in the noncooperative task, but less on the ipsilateral compared with the contralateral side during the cooperative task. The ratio of ipsilateral/contralateral somatosensory evoked potential amplitude was thus significantly larger during the cooperative task compared with the control task and the resting condition. This indicates a functional role of ipsilateral pathways connecting the cervical spinal cord with the cortex during the cooperative task. These observations favor the idea of a task-specific mediation of sensory input from both hands to the ipsilateral and contralateral hemispheres as the basis of neuronal coupling. PMID:25340563

  15. Electrophysiological evidence of a sound localizing binaural subsystem in the human auditory brainstem.

    PubMed

    Pratt, H; Polyakov, A

    1996-01-01

    The binaural interaction components of auditory brainstem evoked potentials reflect electrical changes which are specific to binaural stimuli. Analysis of these components indicated that different click lateralizations result in spatially distinct distributions of activity in the pons, but not at more peripheral levels. The effects of ipsilateral and binaural masking on evoked activity indicated distinct binaurally- and monaurally-activated neural subsets in the human brainstem. These results on the effects of noise and the distinct distributions of pontine activity to different lateralizations provide the first electrophysiological evidence that the auditory system in the humans pons includes a subset which is specific to binaurally presented sounds and which is anatomically distributed according to the lateralization of the sound. These results suggest auditory spatial mapping, similar to other sensory systems. In contrast to other systems, in which mapping is according to receptor distribution in the periphery, auditory spatial mapping is achieved computationally at central levels of the pathway. PMID:8910139

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

    PubMed Central

    Polat, Zahra; Ata?, Ahmet

    2014-01-01

    Background: In the literature, music education has been shown to enhance auditory perception for children and young adults. When compared to young adult non-musicians, young adult musicians demonstrate increased auditory processing, and enhanced sensitivity to acoustic changes. The evoked response potentials associated with the interpretation of sound are enhanced in musicians. Studies show that training also changes sound perception and cortical responses. The earlier training appears to lead to larger changes in the auditory cortex. Aims: Most cortical studies in the literature have used pure tones or musical instrument sounds as stimuli signals. The aim of those studies was to investigate whether musical education would enhance auditory cortical responses when speech signals were used. In this study, the speech sounds extracted from running speech were used as sound stimuli. Study Design: Non-randomized controlled study. Methods: The experimental group consists of young adults up to 21 years-old, all with a minimum of 4 years of musical education. The control group was selected from young adults of the same age without any musical education. The experiments were conducted by using a cortical evoked potential analyser and /m/, /t/ /g/ sound stimulation at the level of 65 dB SPL. In this study, P1 / N1 / P2 amplitude and latency values were measured. Results: Significant differences were found in the amplitude values of P1 and P2 (p<0.05). The differences among the latencies were not found to be significantly important (p>0.05). Conclusion: The results obtained in our study indicate that musical experience has an effect on the nervous system and this can be seen in cortical auditory evoked potentials recorded when the subjects hear speech. PMID:25667787

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

    NASA Technical Reports Server (NTRS)

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

    1972-01-01

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

  18. Short latency evoked somatosensory potentials after stimulation of the median nerve in children: normative data.

    PubMed

    Doria-Lamba, Laura; Montaldi, Luciano; Grosso, Paolo; Veneselli, Edvige; Giribaldi, Gaia

    2009-06-01

    Purpose of the present study was to investigate the early cortical somatosensory evoked potentials after median nerve stimulation and to determine normative data as a function of age. Two hundred forty subjects aged 1 day to 18 years were studied to determine standards of normality during maturation to establish the growth curve. The N9, N13, and N20 components were present in all patients. These components decreased in latency until 4 to 5 years of age because of central nervous system maturation after which latencies increased until adulthood, on the basis of brain and body growth. PMID:19424081

  19. Underwater Anesthesia of Diamondback Terrapins (Malaclemys terrapin) for Measurement of Auditory Evoked Potentials

    PubMed Central

    Christiansen, Emily F; Piniak, Wendy E D; Lester, Lori A; Harms, Craig A

    2013-01-01

    Investigations into the biology of aquatic and semiaquatic species, including those involving sensory specialization, often require creative solutions to novel questions. We developed a technique for safely anesthetizing a semiaquatic chelonian species, the diamondback terrapin (Malaclemys terrapin), for measurement of auditory evoked potentials while animals were completely submerged in water. Custom-modified endotracheal tubes were used to obtain a watertight seal on both sides of the glottis and prevent aspiration of water during testing. No adverse effects were seen after the procedures, and assessment of venous blood-gas partial pressures and lactate concentrations indicated that sufficient gas exchange was maintained under anesthesia through manual ventilation. PMID:24351768

  20. Transcranial electrical motor evoked potentials as a prognostic indicator for motor recovery in stroke patients.

    PubMed Central

    Dominkus, M; Grisold, W; Jelinek, V

    1990-01-01

    Transcranial electrical motor evoked potentials (MEP) were examined in 33 patients within three days after stroke. Normal values for MEP and motor central conduction time (CCT) were obtained in 46 healthy controls whose MEPs were evaluated during slight voluntary muscle contraction and at rest. Two months later 23 patients were re-examined clinically and electrophysiologically. Motor function change was correlated with MEP results. Two months after stroke the patients with normal or prolonged CCT had an improved motor function compared with those with absent CCT. MEP may be a valuable prognostic indicator in the acute stage of paralytic stroke for recovery of motor function. PMID:2174076

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

    Microsoft Academic Search

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

    2011-01-01

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

  2. Control of humanoid robot via motion-onset visual evoked potentials

    PubMed Central

    Li, Wei; Li, Mengfan; Zhao, Jing

    2015-01-01

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

  3. Peripheral electrical stimulation triggered by self-paced detection of motor intention enhances motor evoked potentials.

    PubMed

    Niazi, Imran Khan; Mrachacz-Kersting, Natalie; Jiang, Ning; Dremstrup, Kim; Farina, Dario

    2012-07-01

    This paper proposes the development and experimental tests of a self-paced asynchronous brain-computer interfacing (BCI) system that detects movement related cortical potentials (MRCPs) produced during motor imagination of ankle dorsiflexion and triggers peripheral electrical stimulations timed with the occurrence of MRCPs to induce corticospinal plasticity. MRCPs were detected online from EEG signals in eight healthy subjects with a true positive rate (TPR) of 67.15 ± 7.87% and false positive rate (FPR) of 22.05 ±9.07%. The excitability of the cortical projection to the target muscle (tibialis anterior) was assessed before and after the intervention through motor evoked potentials (MEP) using transcranial magnetic stimulation (TMS). The peak of the evoked potential significantly (P=0.02) increased after the BCI intervention by 53 ± 43% (relative to preintervention measure), although the spinal excitability (tested by stretch reflexes) did not change. These results demonstrate for the first time that it is possible to alter the corticospinal projections to the tibialis anterior muscle by using an asynchronous BCI system based on online motor imagination that triggered peripheral stimulation. This type of repetitive proprioceptive feedback training based on self-generated brain signal decoding may be a requirement for purposeful skill acquisition in intact humans and in the rehabilitation of persons with brain damage. PMID:22547461

  4. Median nerve blockade during diagnostic intravenous regional anesthesia as measured by somatosensory evoked potentials.

    PubMed

    Lang, E; Erdmann, K; Gerbershagen, H U

    1993-01-01

    Intravenous regional anesthesia (IVRA) may be used as a diagnostic method in patients suffering from chronic pain in the forearm or hand to differentiate the origin of pain within the anesthetic area from that above. For this purpose it needs to be proven that all nerve fibers are blocked and that conduction blockade induced by IVRA takes place within the nerve trunks. Therefore the transmission of impulses in a nerve trunk to the central nervous system has been studied. Diagnostic intravenous regional anesthesia (5 mg/kg mepivacaine 1%) of the arm was performed in eight patients for 30 min. Short-latency somatosensory evoked potentials (SSEPs) induced by median nerve stimulation at the wrist were recorded from the scalp at 5-min intervals before, during, and after IVRA. In five patients, sensory nerve action potentials (SNAPs) of the median nerve, at the elbow and axilla, and SSEPs at spinous processus C-7 were recorded simultaneously. During IVRA the function of the nerve fibers which are assumed to mediate pain was tested by the patient's sensation following median nerve stimulation at an intensity which evoked pain before IVRA. During IVRA, peak latencies of the scalp recorded SSEPs (N20) increased progressively and interpeak amplitudes (N20/P25) decreased. After 20 min, SSEPs could no longer be recorded, and median nerve stimulation no longer evoked any sensation at all. After deflation of the cuff, both peak latency (N20) and interpeak amplitude (N20/P25) of SSEPs recovered. The changes in latency and amplitude of SSEPs from the scalp as well as SNAPs and SSEPs from the neck were similar. Because SSEPs, SNAPs, and the pain sensation following median nerve stimulation disappeared during IVRA, it may be concluded that the thick and thin myelinated nerve fibers of the median nerve have been blocked. For diagnostic use, IVRA is superior to peripheral nerve blockade, which has been shown previously to not abolish SSEPs. PMID:8418712

  5. Lateral Geniculate Body Evoked Potentials Elicited by Visual and Electrical Stimulation

    PubMed Central

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

    2014-01-01

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

  6. The impact of synaptic conductance on action potential waveform: evoking realistic action potentials with a simulated synaptic conductance.

    PubMed

    Johnston, Jamie; Postlethwaite, Michael; Forsythe, Ian D

    2009-10-15

    Most current clamp studies trigger action potentials (APs) by step current injection through the recording electrode and assume that the resulting APs are essentially identical to those triggered by orthodromic synaptic inputs. However this assumption is not always valid, particularly when the synaptic conductance is of large magnitude and of close proximity to the axon initial segment. We addressed this question of similarity using the Calyx of Held/MNTB synapse; we compared APs evoked by long duration step current injections, short step current injections and orthodromic synaptic stimuli. Neither injected current protocol evoked APs that matched the evoked orthodromic AP waveform, showing differences in AP height, half-width and after-hyperpolarization. We postulated that this 'error' could arise from changes in the instantaneous conductance during the combined synaptic and AP waveforms, since the driving forces for the respective ionic currents are integrating and continually evolving over this time-course. We demonstrate that a simple Ohm's law manipulation of the EPSC waveform, which accounts for the evolving driving force on the synaptic conductance during the AP, produces waveforms that closely mimic those generated by physiological synaptic stimulation. This stimulation paradigm allows supra-threshold physiological stimulation (single stimuli or trains) without the variability caused by quantal fluctuation in transmitter release, and can be implemented without a specialised dynamic clamp system. Combined with pharmacological tools this method provides a reliable means to assess the physiological roles of postsynaptic ion channels without confounding affects from the presynaptic input. PMID:19560491

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

    PubMed Central

    Kim, Soyeon; Banaschewski, Tobias; Tannock, Rosemary

    2014-01-01

    Background Individuals with attention-deficit/hyperactivity disorder (ADHD) are reported to manifest visual problems (including ophthalmological and color perception, particularly for blue–yellow stimuli), but findings are inconsistent. Accordingly, this study investigated visual function and color perception in adolescents with ADHD using color Visual Evoked Potentials (cVEP), which provides an objective measure of color perception. Method Thirty-one adolescents (aged 13–18), 16 with a confirmed diagnosis of ADHD, and 15 healthy peers, matched for age, gender, and IQ participated in the study. All underwent an ophthalmological exam, as well as electrophysiological testing color Visual Evoked Potentials (cVEP), which measured the latency and amplitude of the neural P1 response to chromatic (blue–yellow, red–green) and achromatic stimuli. Result No intergroup differences were found in the ophthalmological exam. However, significantly larger P1 amplitude was found for blue and yellow stimuli, but not red/green or achromatic stimuli, in the ADHD group (particularly in the medicated group) compared to controls. Conclusion Larger amplitude in the P1 component for blue–yellow in the ADHD group compared to controls may account for the lack of difference in color perception tasks. We speculate that the larger amplitude for blue–yellow stimuli in early sensory processing (P1) might reflect a compensatory strategy for underlying problems including compromised retinal input of s-cones due to hypo-dopaminergic tone. PMID:25435188

  8. Painful stimuli evoke potentials recorded from the medial temporal lobe in humans

    PubMed Central

    Liu, C.C.; Ohara, S.; Franaszczuk, P.; Zagzoog, N.; Gallagher, M.; Lenz, F.A.

    2009-01-01

    The role of human medial temporal structures in fear conditioning has led to the suggestion that neurons in these structures might respond to painful stimuli. We have now tested the hypothesis that recordings from these structures will demonstrate potentials related to the selective activation of cutaneous nociceptors by a painful laser stimulus (laser evoked potential, LEP)(Kenton et al., 1980). Recordings were carried out through electrodes implanted bilaterally in these structures for the investigation of intractable epilepsy. Reproducible LEPs were commonly recorded both bilaterally and unilaterally, while LEPs were recorded at contacts on the left (9/14, P=0.257) as commonly as on the right (5/14), independent of the hand stimulated. Along electrodes traversing the amygdala the majority of LEPs were recorded from dorsal contacts near the central nucleus of the amygdala and the nucleus basalis. Stimulus evoked changes in theta activity were observed at contacts on the right at which isolated early negative LEPs (N2*) responses could be recorded. Contacts at which LEPs could be recorded were as commonly located in medial temporal structures with evidence of seizure activity as on those without. These results demonstrate the presence of pain-related inputs to the medial temporal lobe where they may be involved in associative learning to produce anxiety and disability related to painful stimuli. PMID:19925853

  9. Ground-truthing evoked potential measurements against behavioral conditioning in the goldfish, Carassius auratus

    NASA Astrophysics Data System (ADS)

    Hill, Randy J.; Mann, David A.

    2005-04-01

    Auditory evoked potentials (AEPs) have become commonly used to measure hearing thresholds in fish. However, it is uncertain how well AEP thresholds match behavioral hearing thresholds and what effect variability in electrode placement has on AEPs. In the first experiment, the effect of electrode placement on AEPs was determined by simultaneously recording AEPs from four locations on each of 12 goldfish, Carassius auratus. In the second experiment, the hearing sensitivity of 12 goldfish was measured using both classical conditioning and AEP's in the same setup. For behavioral conditioning, the fish were trained to reduce their respiration rate in response to a 5 s sound presentation paired with a brief shock. A modified staircase method was used in which 20 reversals were completed for each frequency, and threshold levels were determined by averaging the last 12 reversals. Once the behavioral audiogram was completed, the AEP measurements were made without moving the fish. The recording electrode was located subdermally over the medulla, and was inserted prior to classical conditioning to minimize handling of animal. The same sound stimuli (pulsed tones) were presented and the resultant evoked potentials were recorded for 1000-6000 averages. AEP input-output functions were then compared to the behavioral audiogram to compare techniques for estimating behavioral thresholds from AEP data.

  10. Correlation between acceleration magnitude and ocular vestibular-evoked myogenic potential.

    PubMed

    Wang, Shou-Jen; Jaw, Fu-Shan; Young, Yi-Ho

    2012-05-10

    This study combined bone-conducted vibration (BCV) stimulation with triaxial accelerometry to correlate the acceleration magnitudes of BCV stimuli with ocular vestibular-evoked myogenic potential (oVEMP) test results. Fourteen healthy volunteers underwent oVEMP test using BCV stimuli with simultaneous monitoring the triaxial acceleration. All (100%) subjects exhibited clear oVEMPs in response to BCV stimuli from a vibrator. The lowest acceleration magnitudes for eliciting oVEMPs along the x-, y- and z-axes were 0.05±0.01 g, 0.16±0.08 g, and 0.04±0.01 g, respectively, exhibiting significantly higher acceleration magnitude along the y-axis than those along the x- and z-axes. In addition, significantly positive correlations were noted between the acceleration magnitude along each axis and the oVEMP amplitude. In conclusion, measuring the acceleration magnitude throughout oVEMP testing revealed a significant correlation between linear acceleration and oVEMP responses. Restated, increasing acceleration magnitude may have more synchronization of firing of vestibular afferents, resulting in more synchronized evoked potentials and greater oVEMP amplitude. PMID:22484484

  11. Diminished N1 Auditory Evoked Potentials to Oddball Stimuli in Misophonia Patients

    PubMed Central

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

    2014-01-01

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

  12. Diagnostic use of dermatomal somatosensory-evoked potentials in spinal disorders: Case series

    PubMed Central

    Dikmen, Pinar Yalinay; Oge, A. Emre

    2013-01-01

    Objective/Context Dermatomal somatosensory-evoked potentials (dSEPs) may be valuable for diagnostic purposes in selected cases with spinal disorders. Design Reports on cases with successful use of dSEPs. Findings Cases 1 and 2 had lesions causing multiple root involvement (upper to middle lumbar region in Case 1 and lower sacral region in Case 2). Cystic lesions in both cases seemed to compress more than one nerve root, and stimulation at the center of the involved dermatomes in dSEPs helped to reveal the functional abnormality. Cases 3 and 4 had lesions involving the spinal cord with or without nerve root impairment. In Case 3, an magnetic resonance imaging (MRI)-verified lesion seemed to occupy a considerable volume of the lower spinal cord, causing only very restricted clinical sensory and motor signs. In Case 4, a cervical MRI showed a small well-circumscribed intramedullary lesion at right C2 level. All neurophysiological investigations were normal in the latter two patients (motor, tibial, and median somatosensory-evoked potentials in Case 3, and electromyography in both) except for the dSEPs. Conclusions Objectifying the presence and degree of sensory involvement in spinal disorders may be helpful for establishing diagnoses and in therapeutic decision-making. Valuable information could be provided by dSEPs in selected patients with multiple root or spinal cord involvement. PMID:24089995

  13. Combined Muscle Motor and Somatosensory Evoked Potentials for Intramedullary Spinal Cord Tumour Surgery

    PubMed Central

    Choi, Il; Hyun, Seung-Jae; Kang, Joong-Koo

    2014-01-01

    Purpose To evaluate whether intraoperative neurophysiologic monitoring (IONM) with combined muscle motor evoked potentials (mMEPs) and somatosensory evoked potentials is useful for more aggressive and safe resection in intramedullary spinal cord tumour (IMSCT) surgery. Materials and Methods We reviewed data from consecutive patients who underwent surgery for IMSCT between 1998 and April 2012. The patients were divided into two groups based on whether or not IONM was applied. In the monitored group, the procedures were performed under IONM using 75% muscle amplitude decline weaning criteria. The control group was comprised of patients who underwent IMSCT surgery without IONM. The primary outcome was the rate of gross total excision of the tumour on magnetic resonance imaging at one week after surgery. The secondary outcome was the neurologic outcome based on the McCormick Grade scale. Results The two groups had similar demographics. The total gross removal tended to increase when intraoperative neurophysiologic monitoring was used, but this tendency did not reach statistical significance (76% versus 58%; univariate analysis, p=0.049; multivariate regression model, p=0.119). The serial McCormick scale score was similar between the two groups (based on repeated measure ANOVA). Conclusion Our study evaluated combined IONM of trans-cranial electrical (Tce)-mMEPs and SEPs for IMSCT. During IMSCT surgery, combined Tce-mMEPs and SEPs using 75% muscle amplitude weaning criteria did not result in significant improvement in the rate of gross total excision of the tumour or neurologic outcome. PMID:24954338

  14. Evoked Potentials and Neuropsychological Tests Validate Positron Emission Topography (PET) Brain Metabolism in Cognitively Impaired Patients

    PubMed Central

    Braverman, Eric R.; Blum, Kenneth; Damle, Uma J.; Kerner, Mallory; Dushaj, Kristina; Oscar-Berman, Marlene

    2013-01-01

    Fluorodeoxyglucose (FDG) Positron Emission Topography (PET) brain hypometabolism (HM) correlates with diminished cognitive capacity and risk of developing dementia. However, because clinical utility of PET is limited by cost, we sought to determine whether a less costly electrophysiological measure, the P300 evoked potential, in combination with neuropsychological test performance, would validate PET HM in neuropsychiatric patients. We found that patients with amnestic and non-amnestic cognitive impairment and HM (n?=?43) evidenced significantly reduced P300 amplitudes, delayed latencies, and neuropsychological deficits, compared to patients with normal brain metabolism (NM; n?=?187). Data from patients with missing cognitive test scores (n?=?57) were removed from the final sample, and logistic regression modeling was performed on the modified sample (n?=?173, p?=?.000004). The logistic regression modeling, based on P300 and neuropsychological measures, was used to validate membership in the HM vs. NM groups. It showed classification validation in 13/25 HM subjects (52.0%) and in 125/148 NM subjects (84.5%), correlating with total classification accuracy of 79.8%. In this paper, abnormal P300 evoked potentials coupled with cognitive test impairment validates brain metabolism and mild/moderate cognitive impairment (MCI). To this end, we cautiously propose incorporating electrophysiological and neuropsychological assessments as cost-effective brain metabolism and MCI indicators in primary care. Final interpretation of these results must await required additional studies confirming these interesting results. PMID:23526928

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

    PubMed Central

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

    2013-01-01

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

  16. Pericellular Ca(2+) recycling potentiates thrombin-evoked Ca(2+) signals in human platelets.

    PubMed

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

    2013-10-01

    We have previously demonstrated that Na(+)/Ca(2+) exchangers (NCXs) potentiate Ca(2+) signaling evoked by thapsigargin in human platelets, via their ability to modulate the secretion of autocoids from dense granules. This link was confirmed in platelets stimulated with the physiological agonist, thrombin, and experiments were performed to examine how Ca(2+) removal by the NCX modulates platelet dense granule secretion. In cells loaded with the near-membrane indicator FFP-18, thrombin stimulation was observed to elicit an NCX-dependent accumulation of Ca(2+) in a pericellular region around the platelets. To test whether this pericellular Ca(2+) accumulation might be responsible for the influence of NCXs over platelet function, platelets were exposed to fast Ca(2+) chelators or had their glycocalyx removed. Both manipulations of the pericellular Ca(2+) rise reduced thrombin-evoked Ca(2+) signals and dense granule secretion. Blocking Ca(2+)-permeable ion channels had a similar effect, suggesting that Ca(2+) exported into the pericellular region is able to recycle back into the platelet cytosol. Single cell imaging with extracellular Fluo-4 indicated that thrombin-evoked rises in extracellular [Ca(2+)] occurred within the boundary described by the cell surface, suggesting their presence within the open canalicular system (OCS). FFP-18 fluorescence was similarly distributed. These data suggest that upon thrombin stimulation, NCX activity creates a rise in [Ca(2+)] within the pericellular region of the platelet from where it recycles back into the platelet cytosol, acting to both accelerate dense granule secretion and maintain the initial rise in cytosolic [Ca(2+)]. PMID:24303163

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

    PubMed

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

    1995-05-15

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

  18. Possible confounding effects of strobe "clicks" on flash evoked potentials in rats.

    PubMed

    Herr, D W; Vo, K T; King, D; Boyes, W K

    1996-02-01

    Flash evoked potentials (FEPs) undergo within- and between-session changes and are modified by auditory white noise (26). We examined whether an auditory potential produced by the "click" associated with the strobe discharge could be recorded, and if alterations in an auditory response could explain the within- and between-session changes in FEPs. We also examined differences between a frontal cortex or a nasal reference electrode location on FEPs and auditory potentials. An auditory potential associated with the strobe discharge could be clearly recorded. This response was eliminated by the presence of 80 dB SPL masking white noise. However, the within- and between-session changes in FEPs could not be explained by modifications of the auditory potential. Animals whose ear drums were ruptured did not exhibit an auditory response, and their FEPs were similar to those of controls tested in the presence of masking white noise. A nasal reference electrode decreased the impact of auditory potentials on FEPs, but allow visual potentials (electroretinogram and optic tract activity) to influence FEPs. The data show that auditory potentials associated with the strobe discharge can be recorded from the visual cortex of rats, and that these auditory responses represent a possible confounding factor in the interpretation of toxicological studies employing FEPs. PMID:8838613

  19. Micro-field evoked potentials recorded from the porcine sub-dural cortical surface utilizing a microelectrode array.

    PubMed

    Kitzmiller, Joseph P; Hansford, Derek J; Fortin, Linda D; Obrietan, Karl H; Bergdall, Valerie K; Beversdorf, David Q

    2007-05-15

    A sub-dural surface microelectrode array designed to detect micro-field evoked potentials has been developed. The device is comprised of an array of 350-microm square gold contacts, with bidirectional spacing of 150 microm, contained within a polyimide Kapton material. Cytotoxicity testing suggests that the device is suitable for use with animal and human patients. Implementation of the device in animal studies revealed that reliable evoked potentials could be acquired. Further work will be needed to determine how these micro-field potentials, which demonstrate selectivity for one eye, relate to the distribution of the ocular dominance columns of the occipital cortex. PMID:17298849

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

    PubMed

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

    2014-09-01

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

  1. Evaluation of evoked potentials and lymphocyte subsets as possible markers of multiple sclerosis: one year follow up of 30 patients.

    PubMed Central

    Ghezzi, A; Zaffaroni, M; Caputo, D; Montanini, R; Cazzullo, C L

    1986-01-01

    Evoked potentials and T-lymphocyte helper/suppressor ratio (H/S) were evaluated serially together with neurological status in 30 definite multiple sclerosis patients to evaluate their possible role in monitoring disease progression. Evoked potentials in many cases reflected the clinical status of the pathways tested, but some exceptions were observed, probably due to subclinical relapses or physical factors. In some instances the occurrence of subclinical relapses was suggested by increased H/S ratios. Serial H/S values increased in parallel with clinical and subclinical relapses, and seemed to show specific patterns in relation to the type of clinical course (relapsing, stable, chronic progressive). Our results suggest that evoked potentials and H/S ratio serial analysis can contribute to a better assessment of the progress of multiple sclerosis. PMID:3489075

  2. Temperature dependence and independence of effects of pentobarbital on visual evoked potentials of rats.

    PubMed

    Hetzler, B E; Krekow, L K

    1999-01-01

    Visual cortex flash evoked potentials (FEPs), pattern reversal evoked potentials (PREPs), and body temperature were measured in hooded rats following IP injections on separate days of saline, and of 15 and 30 mg pentobarbital/kg body weight. Two experiments were performed, differentiated by standard (23 degrees C) and warm (31 degrees C) room temperatures. The 30 mg/kg dose produced hypothermia of 2.6 degrees C in the standard environment, but not in the warm environment. Early components of FEPs were generally increased in amplitude by the 15 mg/kg dose, and decreased by the 30 mg/kg dose at 23 degrees C. At 31 degrees C, the 30 mg/kg dose did not decrease early component amplitude, suggesting that hypothermia can potentiate some effects of pentobarbital. Amplitudes of late FEP components were depressed at both ambient temperatures. The main PREP components N1P1 and P1N3 were increased in amplitude by the 15 mg/kg dose, but returned to near baseline levels at 30 mg/kg, at both temperatures. PREP component N2P2 was reduced in amplitude by the 30 mg/kg dose only at 23 degrees C. Treatment with 30 mg/kg pentobarbital increased FEP and PREP latencies at both ambient temperatures, but the magnitudes of the increases at 31 degrees C were typically less than half those observed at 23 degrees C. These results indicate that hypothermia contributes to some pentobarbital-induced changes in both FEPs and PREPs, but that pentobarbital also produces effects independent of hypothermia. PMID:10192279

  3. Dynamics of evoked local field potentials in the hippocampus of epileptic rats with spontaneous seizures.

    PubMed

    Queiroz, Claudio M; Gorter, Jan A; Lopes da Silva, Fernando H; Wadman, Wytse J

    2009-03-01

    A change in neuronal network excitability within the hippocampus is one of the hallmarks of temporal lobe epilepsy (TLE). In the dentate gyrus (DG), however, neuronal loss and mossy fiber sprouting are associated with enhanced inhibition rather than progressive hyperexcitability. The aim of this study was to investigate how alterations in excitability take place in association with spontaneous seizures expressed in the DG before, during, and after a seizure. For this purpose, we used freely moving rats that had developed spontaneous seizures after a kainate-induced status epilepticus (SE). Continuous EEG was recorded in the DG during several days along with local field potentials (LFPs) that were evoked every 15-30 s by applying paired-pulse stimuli to the angular bundle. Input-output relations showed increased paired pulse depression in epileptic compared with control rats, suggesting a rather strong inhibition in the DG during the interictal state. A characteristic pattern of changes in intrinsic excitability was observed during the ictal period: an increase in the population spike (PS) amplitude, mostly during the early phase of a seizure and often followed by a decrease of the main evoked potential amplitude. The paired-pulse extracellular postsynaptic potential (fEPSP) ratio increased during the seizure and did slowly recover to preictal levels after the seizure ended. Although clear changes in excitability occurred during and after seizure activity, changes of LFP parameters were more subtle before seizure onset; a significant reduction of LFP and PS amplitudes was observed that started 1-2 min in advance in approximately 33% of the cases; in approximately 18%, an increase of LFP/PS amplitude was observed; in the other cases, no significant change was observed. Taken together, these results provide evidence that, in this experimental model, DG physiology is more likely to follow the already ongoing seizure activity rather than to contribute to its generation. PMID:18842951

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

    E-print Network

    Price, Theodore

    The cannabinoid WIN 55,212-2 inhibits transient receptor potential vanilloid 1 (TRPV1) and evokes by dephosphorylating and desensitizing transient receptor potential vanilloid 1 (TRPV1) via a calcium calcineurin, dephosphorylated TRPV1. The WIN-induced desensitization of TRPV1 was mediated by calcineurin, because

  5. Sensory-evoked LTP driven by dendritic plateau potentials in vivo.

    PubMed

    Gambino, Frédéric; Pagès, Stéphane; Kehayas, Vassilis; Baptista, Daniela; Tatti, Roberta; Carleton, Alan; Holtmaat, Anthony

    2014-11-01

    Long-term synaptic potentiation (LTP) is thought to be a key process in cortical synaptic network plasticity and memory formation. Hebbian forms of LTP depend on strong postsynaptic depolarization, which in many models is generated by action potentials that propagate back from the soma into dendrites. However, local dendritic depolarization has been shown to mediate these forms of LTP as well. As pyramidal cells in supragranular layers of the somatosensory cortex spike infrequently, it is unclear which of the two mechanisms prevails for those cells in vivo. Using whole-cell recordings in the mouse somatosensory cortex in vivo, we demonstrate that rhythmic sensory whisker stimulation efficiently induces synaptic LTP in layer 2/3 (L2/3) pyramidal cells in the absence of somatic spikes. The induction of LTP depended on the occurrence of NMDAR (N-methyl-d-aspartate receptor)-mediated long-lasting depolarizations, which bear similarities to dendritic plateau potentials. In addition, we show that whisker stimuli recruit synaptic networks that originate from the posteromedial complex of the thalamus (POm). Photostimulation of channelrhodopsin-2 expressing POm neurons generated NMDAR-mediated plateau potentials, whereas the inhibition of POm activity during rhythmic whisker stimulation suppressed the generation of those potentials and prevented whisker-evoked LTP. Taken together, our data provide evidence for sensory-driven synaptic LTP in vivo, in the absence of somatic spiking. Instead, LTP is mediated by plateau potentials that are generated through the cooperative activity of lemniscal and paralemniscal synaptic circuitry. PMID:25174710

  6. Sleep and benign partial epilepsies of childhood: EEG and evoked potentials study.

    PubMed

    Dalla Bernardina, B; Sgrò, V; Caraballo, R; Fontana, E; Colamaria, V; Zullini, E; Simone, M; Zanetti, R

    1991-01-01

    The electroclinical picture and nosological limits of benign partial epilepsy of childhood with rolandic spikes (BERS) have been better defined by nocturnal sleep records. In all stages of sleep, there is a significant increase in frequency and amplitude of rolandic spikes (RS) without change of their morphology. Another interesting observation is the appearance of independent spike foci in sleep, or brief subclinical spike wave discharges which are limited to the state of drowsiness. More recently, other types of partial epilepsy of childhood with benign evolution have been identified: (a) partial epilepsy with induced spike representing somatosensory evoked potentials; (b) benign psychomotor epilepsy; (c) partial epilepsy with occipital spike waves. In all these forms, the sleep records are essentially similar to those in BERS and have been very helpful in the nosological identification of these forms of epilepsy. For this reason, the sleep records of these special forms are truly informative for the clinician from the diagnostic and prognostic viewpoint. On the other hand, some investigators, have pointed out that, in the initial stage of these benign forms of partial epilepsy, there may be more or less significant intellectual impairment and behavioral disorder, sometimes accompanied by frequent brief absences. From the EEG viewpoint, this condition is characterized by brief discharges of slow spike wave complexes amounting to a pattern of "electrical status epilepticus". This special electroclinical condition mimics the Lennox-Gastaut syndrome but is generally self-limited. Thus, a correct differential diagnosis is very important from the diagnostic viewpoint. There is good evidence that sleep records permit an earlier identification of these conditions and strongly contribute to a correct differential diagnosis. In the benign partial epilepsy the SEPs, during awake and sleep, morphology and latency are normal, while the N60 amplitude is increased. A group of children with benign partial epilepsy shows EEG spikes evoked by tapping, and giant N60 component. This giant component persists during sleep and is not specific for any type of benign partial epilepsy. In conclusion, the results of sleep recordings are conducive to a correct diagnosis and better definition of the nosological delineation of partial epilepsies in childhood; they also provide a better comprehension of their evolution, and thus of their prognosis. The Evoked Potentials seem be a useful tool in the study of benign partial epilepsy. PMID:1760100

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

    PubMed Central

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

    2013-01-01

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

  8. Effects of peripherally and centrally acting analgesics on somato-sensory evoked potentials.

    PubMed Central

    Moore, U J; Marsh, V R; Ashton, C H; Seymour, R A

    1995-01-01

    1. The effects of aspirin 1000 mg, paracetamol 1000 mg, codeine 60 mg on somatosensory evoked potentials (SEPs) were measured in a four-way cross-over study. 2. SEPs were elicited by electrical stimulation of the skin overlying the digital nerve at intensities close to pain threshold. 3. Amplitudes and latencies of both early and late SEPs were recorded, as well as first sensory threshold and subjective pain threshold. 4. None of the study medications affected the amplitude or latency of the late SEP components (100-250 ms post-stimulus). The amplitude of early components (15-30 ms post-stimulus) was also unaffected, but aspirin shortened the latency 30 min after ingestion. 5. Sensory detection and pain threshold to electrical skin stimulation were also unaffected by any of the study medications despite subjective central effects with codeine. PMID:8562292

  9. Effects of diabetes mellitus type ? with or without neuropathy on vestibular evoked myogenic potentials.

    PubMed

    Kamali, Behnoush; Hajiabolhassan, Fahimeh; Fatahi, Jamileh; Nasli Esfahani, Ensieh; Sarrafzadeh, Javad; Faghihzadeh, Soghrat

    2013-01-01

    Diabetes mellitus type ? is a metabolic disorder that affects multiple systems including the inner ear. Patients with diabetes mellitus commonly complain about dizziness, floating sensation, tinnitus and sweating. The aim of this study was to compare vestibular evoked myogenic potentials (VEMPs) between diabetic patients with or without neuropathy. Subjects included 14 patients with diabetes mellitus type ? with polyneuropathy, 10 patients with diabetes mellitus type ? without polyneuropathy and 24 healthy volunteers. Range of age in participants was 15-40 years old. The VEMPs were recorded with 500 Hz tone bursts with intensity at 95 dB. There was statistically significant difference between the groups in P13 and N23 latencies (P<0.05). There was no statistically significant difference between groups in absolute and relative amplitudes. Prolonged latencies of the VEMP suggest lesions in the retrolabyrinthine, especially in the vestibulospinal tract. PMID:23585317

  10. Visually Evoked Potentials in a Patient with a Fyodorov-Zuev Keratoprosthesis

    PubMed Central

    Schwartz, Roy; Barak, Adiel; Newman, Hadas

    2015-01-01

    Purpose To describe a visually evoked potential (VEP) examination performed on a patient with a keratoprosthesis. Methods We report the case of a 60-year-old patient with a Fyodorov-Zuev keratoprosthesis in the right eye complained of gradual visual deterioration in that eye. His past medical history consisted of failed corneal graft procedures due to corneal dystrophy and an Ahmed valve implantation due to secondary glaucoma. A clinical examination and an ultrasound demonstrated vitreal opacities. In order to assess the visual status, a flash VEP test was conducted. Results VEP recorded from the right eye consisted of a broadened and poorly formed positive P1 wave, with a subnormal amplitude, but a normal latency. Consequently, the patient underwent a pars plana vitrectomy. Conclusion This case demonstrates the viability of VEP exams in patients with keratoprostheses.

  11. Visual evoked potential estimation by adaptive noise cancellation with neural-network-based fuzzy inference system.

    PubMed

    Zeng, Y; Zhang, J; Yin, H; Pan, Y

    2007-01-01

    Visual evoked potentials (VEPs) are time-varying signals typically buried in relatively large background noise known as the electroencephalogram (EEG). In this paper, an adaptive noise cancellation with neural network-based fuzzy inference system (NNFIS) was used and the NNFIS was carefully designed to model the VEP signal. It is assumed that VEP responses can be modelled by NNFIS with the centres of its membership functions evenly distributed over time. The weights of NNFIS are adaptively determined by minimizing the variance of the error signal using the least mean squares (LMS) algorithm. As the NNFIS is dynamic to any change of VEP, the non-stationary characteristics of VEP can be tracked. Thus, this method should be able to track the VEP. Four sets of simulated data indicate that the proposed method is appropriate to estimate VEP. A total of 150 trials are processed to demonstrate the superior performance of the proposed method. PMID:17454407

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

    PubMed

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

    2014-01-01

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

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

    PubMed Central

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

    2014-01-01

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

  14. Cerebral hypoxia, missing cortical somatosensory evoked potentials and recovery of consciousness

    PubMed Central

    2014-01-01

    Background Bilaterally absent N20 components of the sensory evoked potentials (SEP) from the median nerve are regarded as accurately predicting poor outcome after cardiac arrest. Case presentation We are reporting on a patient, who regained consciousness despite this ominous finding. Early after cardiac arrest, MRI showed signal alterations in diffusion weighted imaging (DWI) bilaterally in the primary visual and sensorimotor cortex and in the basal ganglia. SEP were repeatedly absent. The patient survived shut out form sensory and visual experience and locked in for voluntary movements, but kept her verbal competence in several languages. Conclusion SEP inform about integrity only of a narrow cortical strip. It is unguarded, but common practice, to conclude from absent SEP, that a patient has suffered diffuse cortical damage after cardiac arrest. Cerebral MRI with DWI helps to avoid this prognostic error and furthers understanding of the sometimes very peculiar state of mind after cardiac arrest. PMID:24720818

  15. Somatosensory evoked potentials elicited by stimulation of lower-limb nerves in amyotrophic lateral sclerosis.

    PubMed

    Georgesco, M; Salerno, A; Camu, W

    1997-07-01

    To determine lower limb somatosensory modifications in amyotrophic lateral sclerosis (ALS), we studied somatosensory evoked potentials (SEPs) elicited by stimulation of tibial posterior nerves (TP), sural nerves (SN), saphenous internous nerves (SA), and medial plantar nerves (PL) of both limbs in 24 ALS patients, and compared the results with those from 17 normal subjects. Responses were recorded according to the international 10-20 system. Normal sensory conduction velocities of SN, SA and PL and H reflexes in soleus muscles were prerequisites for patient inclusion in this study. The results showed marked alterations in SEPs cortical components of all lower limb nerves, which could be related to abnormal sensory transmission (after spinal N22), or cortical abnormalities. We put forward the hypothesis of impairment of pyramidal control of the sensory system and Clark's column involvement to explain such anomalies. It was concluded that SEPs abnormalities in the lower limbs are a common feature in ALS. PMID:9246071

  16. Clinical Utility of Ocular Vestibular-Evoked Myogenic Potentials (oVEMPs).

    PubMed

    Weber, Konrad P; Rosengren, Sally M

    2015-05-01

    Over the last years, vestibular-evoked myogenic potentials (VEMPs) have been established as clinical tests of otolith function. Complementary to the cervical VEMPs, which assess mainly saccular function, ocular VEMPs (oVEMPs) test predominantly utricular otolith function. oVEMPs are elicited either with air-conducted (AC) sound or bone-conducted (BC) skull vibration and are recorded from beneath the eyes during up-gaze. They assess the vestibulo-ocular reflex and are a crossed excitatory response originating from the inferior oblique eye muscle. Enlarged oVEMPs have proven to be sensitive for screening of superior canal dehiscence, while absent oVEMPs indicate a loss of superior vestibular nerve otolith function, often seen in vestibular neuritis (VN) or vestibular Schwannoma. PMID:25773001

  17. Auditory evoked potentials for the assessment of depth of anaesthesia: different configurations of artefact detection algorithms.

    PubMed

    Luecke, Daniela; Stockmanns, Gudrun; Gallinat, Michael; Kochs, Eberhard F; Schneider, Gerhard

    2007-02-01

    Monitoring the depth of anaesthesia has become an important research topic in the field of biosignal processing. Auditory evoked potentials (AEPs) have been shown to be a promising tool for this purpose. Signals recorded in the noisy environment of an operating theatre are often contaminated by artefacts. Thus, artefact detection and elimination in the underlying electroencephalogram (EEG) are mandatory before AEP extraction. Determination of a suitable artefact detection configuration based on EEG data from a clinical study is described. Artefact detection algorithms and an AEP extraction procedure encompassing the artefact detection results are presented. Different configurations of artefact detection algorithms are evaluated using an AEP verification procedure and support vector machines to determine a suitable configuration for the assessment of depth of anaesthesia using AEPs. PMID:17313341

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

    NASA Technical Reports Server (NTRS)

    Odonnell, Brian F.; Cohen, Ronald A.

    1988-01-01

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

  19. Possible Long Term Effects of Chemical Warfare Using Visual Evoked Potentials

    PubMed Central

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

    2014-01-01

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

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

    PubMed

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

    2014-09-01

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

  1. Vertex potentials evoked during auditory signal detection - Relation to decision criteria

    NASA Technical Reports Server (NTRS)

    Squires, K. C.; Hillyard, S. A.; Lindsay, P. H.

    1973-01-01

    Vertex potentials were recorded from eight subjects performing in an auditory threshold detection task with rating scale responses. The amplitudes and latencies of both the N1 and the late positive (P3) components were found to vary systematically with the criterion level of the decision. These changes in the waveshape of the N1 component were comparable to those produced by varying the signal intensity in a passive condition, but the late positive component in the active task was not similarly related to the passively evoked P2 component. It was suggested that the N1 and P3 components represent distinctive aspects of the decision process, with N1 signifying the quantity of signal information received and P3 reflecting the certainty of the decision based upon that information.

  2. [Visual evoked potentials and functional asymmetry in children with with different degrees of intellectual retardation].

    PubMed

    Katargina, T A; Kryzhanovskaia, I L; Petrova, M A

    1993-01-01

    Visual evoked potentials (VEP) to flash and patterned visual stimuli have been recorded from occipital and central brain regions in 7-8-year-old boys with normal intellect (20 cases), with mental retardation (15 cases) and with oligophrenia of a debile degree (27 cases). A significant elongation of late-component latency has been revealed in motor brain areas VEP in oligophrenia group compared to normal subjects. A negative correlation between P190 component latency of motor area VEP to patterned visual stimulus and general and non-verbal intellectual indices has been stated in full right-handed subjects with intellectual deficiency. Such a relation was absent in right-handed patients with left dominant eye. PMID:8042397

  3. [Visual evoked potentials in infants in health and hypoplasia of the optic nerve].

    PubMed

    Fil'chikova, L I; Mosin, I M; Dubovskaia, L A

    1996-01-01

    Visual evoked potentials (VEP) in response to chess field reversion were studied in 29 infants aged from 6 weeks to 1.5 years with optic nerve hypoplasia and in healthy age-matched controls. Analysis of VEP in healthy children showed that the interval between weeks 6-9 and 16-20 of life was the period of their most rapid maturation, this making this period in the development of the optic system of man particularly significant. Three types of VEP disorders were detected in patients with optic nerve hypoplasia; these types correlate with the size of the optic disk and behavioral reactions of a child. Together with the clinical data, VEP may be used for assessing the function of the optic system of children with optic nerve hypoplasia and for early diagnosis of this disease. PMID:9148558

  4. Frequency detection with stability coefficient for steady-state visual evoked potential (SSVEP)-based BCIs

    NASA Astrophysics Data System (ADS)

    Wu, Zhenghua; Yao, Dezhong

    2008-03-01

    Due to the relative noise and artifact insensitivity, steady-state visual evoked potential (SSVEP) has been used increasingly in the study of a brain-computer interface (BCI). However, SSVEP is still influenced by the same frequency component in the spontaneous EEG, and it is meaningful to find a parameter that can avoid or decrease this influence to improve the transfer rate and the accuracy of the SSVEP-based BCI. In this work, with wavelet analysis, a new parameter named stability coefficient (SC) was defined to measure the stability of a frequency, and then the electrode with the highest stability was selected as the signal electrode for further analysis. After that, the SC method and the traditional power spectrum (PS) method were used comparatively to recognize the stimulus frequency from an analogous BCI data constructed from a real SSVEP data, and the results showed that the SC method is better for a short time window data.

  5. Right uninostril yoga breathing influences ipsilateral components of middle latency auditory evoked potentials.

    PubMed

    Raghuraj, P; Telles, S

    2004-12-01

    A previous report described selective electrical activity of the cerebral hemispheres with uninostril breathing. In the present study, middle latency auditory evoked potentials (MLAEPs) were recorded from symmetrical scalp sites during the practice of uninostril yoga breathing. There were two sessions (40 min each) of right nostril yoga breathing (RNB) and of breath awareness (BAW), with (i) 'before', (ii) test (either RNB or BAW) and (iii) 'after' periods. The participants were 14 male volunteers aged between 18 and 33 years, and the setting was a yoga centre. MLAEPs were recorded from symmetrical scalp sites (C4 and C3). During RNB, the peak amplitudes of two negative components (viz. Na wave and Nb wave) were significantly increased on the right side. Increased peak amplitudes of Na and Nb waves suggested that RNB increased the number of neurons recruited on the right side, suggesting a possible application of RNB in certain psychiatric disorders with cerebral hemispheric imbalance. PMID:15624085

  6. sBCI: fast detection of steady-state visual evoked potentials.

    PubMed

    Valbuena, Diana; Volosyak, Ivan; Graser, Axel

    2010-01-01

    Brain-computer interface (BCI) systems enable communication and control without movement. Although advanced signal processing methods are used in BCI research, the output of a BCI is still unreliable, and the information transfer rates are very low compared with conventional human interaction interfaces such as keyboard and mouse. Therefore, improvements in signal classification methods and the exploitation of the learning skills of the user are required to compensate the unreliability of the BCI system. This work analyzes the response time of the Bremen-BCI based on steady-state visual evoked potentials (SSVEP) previously tested on 27 subjects, and presents an enhanced method for faster detection of SSVEP responses. The aim is toward the development of a swift BCI (sBCI) that robustly detects the exact time point where the user starts modulating his brain signals. PMID:21097270

  7. Statistical Modeling and Analysis of Laser-Evoked Potentials of Electrocorticogram Recordings from Awake Humans

    PubMed Central

    Chen, Zhe; Ohara, Shinji; Cao, Jianting; Vialatte, François; Lenz, Fred A.; Cichocki, Andrzej

    2007-01-01

    This article is devoted to statistical modeling and analysis of electrocorticogram (ECoG) signals induced by painful cutaneous laser stimuli, which were recorded from implanted electrodes in awake humans. Specifically, with statistical tools of factor analysis and independent component analysis, the pain-induced laser-evoked potentials (LEPs) were extracted and investigated under different controlled conditions. With the help of wavelet analysis, quantitative and qualitative analyses were conducted regarding the LEPs' attributes of power, amplitude, and latency, in both averaging and single-trial experiments. Statistical hypothesis tests were also applied in various experimental setups. Experimental results reported herein also confirm previous findings in the neurophysiology literature. In addition, single-trial analysis has also revealed many new observations that might be interesting to the neuroscientists or clinical neurophysiologists. These promising results show convincing validation that advanced signal processing and statistical analysis may open new avenues for future studies of such ECoG or other relevant biomedical recordings. PMID:18369410

  8. THIP, a selective gamma-aminobutyric acid receptor agonist, alters flash-evoked potentials in rats.

    PubMed

    Hetzler, B E; Zeisset, H L

    1997-12-01

    This study examined the effects of the GABA(A) agonist THIP on flash-evoked potentials (FEPs) recorded from the primary visual cortex (VC) and superior colliculus (SC) of chronically implanted hooded rats. Animals were given I.P. injections of saline, and of 8, 16, and 24 mg THIP/kg body weight on separate days. Evoked potentials were recorded at 5, 20, and 35 min following injection. Animals were tested at a standard (22.5 degrees C) room temperature. Most significant effects were observed at the 20- and 35-min recording intervals for both the 16 and 24 mg/kg doses, with effects at the 24 mg/kg dose the most pronounced. VC P1 amplitude remained unchanged, while N1 was reduced to such an extent that it became positive, ultimately blending into the rising phase of a positive component appearing between N1 and P2. This positive component had a latency of about 6 ms longer than N1, and became larger in amplitude than P1 at the 24 mg/kg dose. P2 amplitude was drastically reduced, becoming negative. In contrast, components N2 and P3 were augmented, while the amplitude of N3 was unchanged. In the SC, P1 was augmented while P3 was reduced in amplitude. A biphasic (increase/decrease) effect was observed in the N4 complex. In both the VC and SC, latencies of most components were increased, with the late components in the VC increased to the greatest extent. A mild hypothermia was observed at 16 and 24 mg/kg. The results suggest that the GABA(A) receptor plays an important role in the elaboration of the middle (N1-P2) components of FEPs recorded from the rat VC, and that GABAergic mechanisms can influence other components in the VC and SC as well. PMID:9408197

  9. Effects of anesthesia and stimulus intensity on posterior tibial nerve somatosensory evoked potentials.

    PubMed

    Rappaport, M; Leonard, J; Ruiz Portillo, S

    1992-01-01

    Under anesthesia peak latencies occurring up to 75 milliseconds after stimulus onset upon somatosensory evoked potential testing of the somatosensory evoked potential testing of the posterior tibial nerve were not affected by stimulus intensity (between 5 and 19 ma) or by length of time under isoflurane and nitrous oxide up to over 2 hours. When pre- and postoperative tests on patients who were not under anesthesia were compared with results under anesthesia, no significant latency differences were found in relation to stimulus intensity for peaks N30, P40 and N50. For peaks P60 and N75, however, significantly increased latencies were seen during anesthesia, more pronounced and consistent for N75. Amplitudes, however, were affected by both stimulus intensity and anesthesia duration. A curvilinear relationship was found during early anesthesia. Maximum amplitudes were found at 7 or 11 ma stimulus intensity levels, depending upon which peak was analyzed, with lesser amplitudes occurring at both lower and higher stimulus intensity levels. Stimulus intensity and anesthesia interacted such that maximum amplitude occurred, in general, at 11 ma after short duration anesthesia (6') and at 7 ma after long duration anesthesia (125'). Under long duration anesthesia amplitudes were significantly diminished, mostly at the 11 ma intensity level. At 15 and 19 ma intensity levels peak amplitudes remained relatively constant regardless of anesthesia duration and therefore are the intensities to use to monitor changes during prolonged surgeries. When preoperative during prolonged surgeries. When preoperative and postoperative tests were compared to tests under anesthesia, there was a decrease in amplitude under anesthesia, greater for long than short duration anesthesia.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:1733619

  10. Cerebral information processing in personality disorders: I. Intensity dependence of auditory evoked potentials.

    PubMed

    Wang, Wei; Wang, Yehan; Fu, Xianming; Liu, Jianhui; He, Chengsen; Dong, Yi; Livesley, W John; Jang, Kerry L

    2006-02-28

    Patients with personality disorders such as the histrionic type exaggerate their responses when receiving external social or environmental stimuli. We speculated that they might also show an augmenting pattern of the auditory evoked potential N1-P2 component in response to stimuli with increasing levels of intensity, a response pattern that is thought to be inversely correlated with cerebral serotonin (5-HT) activity. To test this hypothesis, we collected auditory evoked potentials in 191 patients with personality disorders (19 patients with the paranoid type, 12 schizoid, 14 schizotypal, 18 antisocial, 15 borderline, 13 histrionic, 17 narcissistic, 25 avoidant, 30 dependent and 28 obsessive-compulsive) and 26 healthy volunteers. Their personality traits were measured using the Dimensional Assessment of Personality Pathology-Basic Questionnaire (DAPP-BQ). Compared with healthy subjects and other patient groups, the histrionic group scored higher on the basic traits Affective Instability, Stimulus Seeking, Rejection and Narcissism, and on the higher traits Emotional Dysregulation and Dissocial, than the other groups, and the schizoid group scored lower on most of the DAPP-BQ basic and higher traits. In addition, the histrionic group showed steeper amplitude/stimulus intensity function (ASF) slopes at three midline scalp electrodes than the healthy controls or the other patient groups. The ASF slopes were not correlated with any DAPP-BQ traits in the total sample of 217 subjects. However, the DAPP-BQ basic trait Rejection was positively correlated with the ASF slopes at all three electrode sites in the histrionic group. The increased intensity dependence of the auditory N1-P2 component might indicate that cerebral 5-HT neuronal activity is, on average, weak in the histrionic patients. PMID:16499979

  11. Inhibitory effects of glutamate-stimulated astrocytes on action potentials evoked by bradykinin in cultured dorsal root ganglion neurons.

    PubMed

    Suzuki, Kazuo; Ono, Minehisa; Tonaka, Kenji

    2014-04-01

    Patch-clamp and Ca2+-imaging techniques have revealed that astrocytes have dynamic properties including ion channel activity and release of neurotransmitters, such as adenosine triphosphate (ATP) and glutamate. Here, we used the patch-clamp technique to determine whether ATP and glutamate is able to modulate the bradykinin (BK) response in neurons cultured with astrocytes in the mouse dorsal root ganglia (DRG) in order to clarify the role of astrocytes in nociceptive signal transmission. Astrocytes were identified using a fluorescent anti-GFAP antibody. The membrane potential of astrocytes was about -39 mV. The application of glutamic acid (GA) to the bath evoked the opening of two types of Cl- channel in the astrocyte cell membrane with a unit conductance of about 380 pS and 35 pS in the cell-attached mode, respectively. ATP application evoked the opening of two types of astrocyte K+ channel with a unit conductance of about 60 pS and 29 pS, respectively. Application of BK to the neuron evoked an action potential (spike). Concomitant BK application with ATP increased the frequency of BK-evoked neuron spikes when neurons coexisted with astrocytes. Stimulation of BK with GA inhibited the BK-evoked spike under similar conditions. The application of furosemide, a potent cotransporter (Na+-K+-2Cl-) inhibitor, prior to stimulation of BK with GA blocked inhibition of the spike. It is thought that inhibition of the spike is related to Cl- movement from astrocytes. PMID:24733593

  12. Motion-onset visual evoked potentials predict performance during a global direction discrimination task

    PubMed Central

    Martin, Tim; Huxlin, Krystel R.; Kavcic, Voyko

    2010-01-01

    The relationship between cognitive processing stages and event-related potential components has been extensively researched for single components, but even the simplest task comprises multiple electrophysiological and cognitive components. Here we examined the relationship between behavioral measures and several visual evoked potentials (VEPs) related to global motion onset during a visual motion discrimination task. In addition to reaction time and accuracy, the EZ diffusion model was used to characterize elements of the decision process. Results showed that latencies, but not amplitudes, from three VEP components reliably predicted about 40% of the variance in reaction times for motion discrimination. These included the latency from stimulus motion onset to N2 onset, the latency from N2 onset to N2 peak, and the latency from the N2 peak to the peak of a late positive potential. These latencies were also able to predict the rate of information accumulation during the decision process and the duration of non-decision processes, but not the observer's threshold (boundary) for making a response. This pattern of results is consistent with an interpretation of these three latencies as reflecting a non-specific visual perceptual process, a motion-specific process, and a decision process respectively. The relationship between the earliest interval and drift rate estimated with the EZ model also supports the notion that early perceptual processing might be a constituent part of the decision process itself. PMID:20713072

  13. Post-exercise facilitation and depression of motor evoked potentials to transcranial magnetic stimulation: a study in multiple sclerosis

    Microsoft Academic Search

    A Perretti; P Balbi; G Orefice; L Trojano; L Marcantonio; V Brescia-Morra; S Ascione; F Manganelli; G Conte; L Santoro

    2004-01-01

    Objective: To evaluate motor cortex excitability changes by transcranial magnetic stimulation (TMS) following repetitive muscle contractions in patients with multiple sclerosis (MS); to state whether a typical pattern of post-exercise motor evoked potentials (MEPs) is related to clinical fatigue in MS.Methods: In 41 patients with definite MS (32 with fatigue and 9 without fatigue according to Fatigue Severity Scale) and

  14. Exercise-induced depression of the diaphragm motor evoked potential is not affected by non-invasive ventilation

    Microsoft Academic Search

    Mark J. Dayer; Sophie Jonville; Michelle Chatwin; Elisabeth B. Swallow; Raphael Porcher; Tarek Sharshar; Ewen T. Ross; Nicholas S. Hopkinson; John Moxham; Michael I. Polkey

    2007-01-01

    Whole body exercise is followed by a depression of the diaphragm motor evoked potential (MEP). It is unknown whether the change is due to diaphragm activity or whole body exercise. To test the hypothesis that exercise-induced MEP depression was related to diaphragm activity, we performed two experiments. The first examined the effect of whole body exercise, performed with and without

  15. Facilitation of motor evoked potentials (MEPs) in first dorsal interosseous (FDI) muscle is dependent on different motor images

    Microsoft Academic Search

    Susumu Yahagi; Tatsuya Kasai

    1998-01-01

    Objective: We investigated changes in motor evoked potentials (MEPs) to explain why mental practice can improve motor performance.Methods: MEPs were recorded from right and left first dorsal interosseous (FDI) muscles of 9 normal, right-handed subjects during different motor images of index finger movement: (1) rest, (2) flexion, (3) abduction, (4) extension. A paired t test was used to compare differences

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

    Microsoft Academic Search

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

    1996-01-01

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

  17. Somatosensory evoked potential spinal cord monitoring reduces neurologic deficits after scoliosis surgery: results of a large multicenter survey

    Microsoft Academic Search

    Marc R. Nuwer; Edgar G. Dawson; Linda G. Carlson; Linda E. A. Kanim; John E. Sherman

    1995-01-01

    Neurologic deficits were compared to somatosensory evoked potential (SEP) spinal cord monitoring in a survey of spinal orthopedic surgeons. Experienced SEP spinal cord monitoring teams had fewer than one-half as many neurologic deficits per 100 cases compared to teams with relatively little monitoring experience. Experienced SEP monitoring teams also had fewer neurologic deficits than were seen in previous surveys of

  18. Longitudinal Study of Averaged Auditory Evoked Potentials in Normal Children from Birth to Three Years of Age.

    ERIC Educational Resources Information Center

    Ohlrich, Elizabeth S.; And Others

    This study examined individual patterns of the maturation of auditory evoked potential (AEP) in normal infants to determine whether longitudinal data show less variability than cross-sectional data, and to further assess the effect of stage of sleep on AEP. The AEPs for 10 children were examined by repeated testing between the ages of about two…

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

    E-print Network

    Paris-Sud XI, Université de

    USEFULLNESS OF FUNCTIONAL MRI ASSOCIATED WITH PET SCAN AND EVOKED POTENTIALS IN THE EVALUATION concordance between fMRI and brain functions suggested by EP and metabolic activity demonstrated with PET OF BRAIN FUNCTIONS AFTER SEVERE BRAIN INJURY : preliminary results. INTERET DE L'IRM FONCTIONNELLE ASSOCIEE

  20. Autoimmune Optic Neuritis in the Common Marmoset Monkey: Comparison of Visual Evoked Potentials with MRI and Histopathology

    Microsoft Academic Search

    Ricarda Diem; Iris Demmer; Susann Boretius; Doron Merkler; Barthel Schmelting; Sarah K. Williams; Muriel B. Sattler; Mathias Bahr; Thomas Michaelis; Jens Frahm; Wolfgang Bruck; Eberhard Fuchs

    PURPOSE. To assess the use of visual evoked potentials (VEPs) for the in vivo detection of impaired visual function in a marmoset model of multiple sclerosis. The sensitivity of the VEP recordings was determined by comparison with magnetic resonance imaging (MRI) and histopathology. METHODS. Baseline VEPs were recorded in six healthy marmo- set monkeys in response to light-flash stimulation. Experimen-

  1. The effect of chronic restraint stress and sulfite on visual evoked potentials (VEPs): Relation to lipid peroxidation

    Microsoft Academic Search

    Selcen Aydin; Piraye Yargicoglu; Narin Derin; Yakup Aliciguzel; ?smail Abidin; Aysel Agar

    2005-01-01

    Stress and sulfite can stimulate numerous pathways leading to an increased production of free radicals which generate a peroxidation cascade producing lipid peroxidation, protein oxidation, DNA damage and cell death, and contribute to the occurrence of pathologic conditions. The purpose of our study was to investigate the effects of stress and sulfite on visual evoked potentials (VEPs) and to examine

  2. Ocular vestibular evoked myogenic potentials to bone conducted vibration of the midline forehead at Fz in healthy subjects

    Microsoft Academic Search

    S. Iwasaki; Y. E. Smulders; A. M. Burgess; L. A. McGarvie; H. G. MacDougall; G. M. Halmagyi; I. S. Curthoys

    2008-01-01

    ObjectiveTo provide the empirical basis for using ocular vestibular evoked myogenic potentials (oVEMPS) in response to Fz bone conducted vibration (BCV) stimulation to indicate vestibular function in human subjects. To show the generality of the response by testing a large number of unselected healthy subjects across a wide age range and the repeatability of the response within subjects. To provide

  3. INHIBITION OF BRAIN CHOLINESTERASE AND THE PHOTIC AFTER DISCHARGE OF FLASH EVOKED POTENTIALS PRODUCED BY CARBARYL IN LONG EVANS RATS.

    EPA Science Inventory

    Carbaryl is a widely used N-methyl carbamate pesticide that acts by inhibiting cholinesterases (ChE), which may lead to cholinergic toxicity. Flash evoked potentials (FEPs) are a neurophysiological response often used to detect central nervous system (CNS) changes following expos...

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

    ERIC Educational Resources Information Center

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

    2008-01-01

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

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

    PubMed

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

    2015-01-01

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

  6. Hemisection spinal cord injury in rat: the value of intraoperative somatosensory evoked potential monitoring.

    PubMed

    Cloud, Beth A; Ball, Bret G; Chen, Bingkun K; Knight, Andrew M; Hakim, Jeffrey S; Ortiz, Ana M; Windebank, Anthony J

    2012-11-15

    Techniques used to produce partial spinal cord injuries in animal models have the potential for creating variability in lesions. The amount of tissue affected may influence the functional outcomes assessed in the animals. The recording of somatosensory evoked potentials (SSEPs) may be a valuable tool for assessing the extent of lesion applied in animal models of traumatic spinal cord injury (SCI). Intraoperative tibial SSEP recordings were assessed during surgically induced lateral thoracic hemisection SCI in Sprague-Dawley rats. The transmission of SSEPs, or lack thereof, was determined and compared against the integrity of the dorsal funiculi on each side of the spinal cord upon histological sectioning. An association was found between the presence of an SSEP signal and presence of intact dorsal funiculus tissue. The relative risk is 4.50 (95% confidence interval: 1.83-11.08) for having an intact dorsal funiculus when the ipsilateral SSEP was present compared to when it was absent. Additionally, the amount of spared spinal cord tissue correlates with final functional assessments at nine weeks post injury: BBB (linear regression, R²=0.618, p<0.001) and treadmill test (linear regression, R²=0.369, p=0.016). Therefore, we propose intraoperative SSEP monitoring as a valuable tool to assess extent of lesion and reduce variability between animals in experimental studies of SCI. PMID:22960163

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

    PubMed

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

    2014-01-01

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

  8. A high-speed brain speller using steady-state visual evoked potentials.

    PubMed

    Nakanishi, Masaki; Wang, Yijun; Wang, Yu-Te; Mitsukura, Yasue; Jung, Tzyy-Ping

    2014-09-01

    Implementing a complex spelling program using a steady-state visual evoked potential (SSVEP)-based brain-computer interface (BCI) remains a challenge due to difficulties in stimulus presentation and target identification. This study aims to explore the feasibility of mixed frequency and phase coding in building a high-speed SSVEP speller with a computer monitor. A frequency and phase approximation approach was developed to eliminate the limitation of the number of targets caused by the monitor refresh rate, resulting in a speller comprising 32 flickers specified by eight frequencies (8-15 Hz with a 1 Hz interval) and four phases (0°, 90°, 180°, and 270°). A multi-channel approach incorporating Canonical Correlation Analysis (CCA) and SSVEP training data was proposed for target identification. In a simulated online experiment, at a spelling rate of 40 characters per minute, the system obtained an averaged information transfer rate (ITR) of 166.91 bits/min across 13 subjects with a maximum individual ITR of 192.26 bits/min, the highest ITR ever reported in electroencephalogram (EEG)-based BCIs. The results of this study demonstrate great potential of a high-speed SSVEP-based BCI in real-life applications. PMID:25081427

  9. The BOLD response and the gamma oscillations respond differently than evoked potentials: an interleaved EEG-fMRI study

    PubMed Central

    Foucher, Jack R; Otzenberger, Hélène; Gounot, Daniel

    2003-01-01

    Background The integration of EEG and fMRI is attractive because of their complementary precision regarding time and space. But the relationship between the indirect hemodynamic fMRI signal and the more direct EEG signal is uncertain. Event-related EEG responses can be analyzed in two different ways, reflecting two different kinds of brain activity: evoked, i.e. phase-locked to the stimulus, such as evoked potentials, or induced, i.e. non phase-locked to the stimulus such as event-related oscillations. In order to determine which kind of EEG activity was more closely related with fMRI, EEG and fMRI signals were acquired together, while subjects were presented with two kinds of rare events intermingled with frequent distractors. Target events had to be signaled by pressing a button and Novel events had to be ignored. Results Both Targets and Novels triggered a P300, of larger amplitude in the Novel condition. On the opposite, the fMRI BOLD response was stronger in the Target condition. EEG event-related oscillations in the gamma band (32–38 Hz) reacted in a way similar to the BOLD response. Conclusions The reasons for such opposite differential reactivity between oscillations / fMRI on the one hand, and evoked potentials on the other, are discussed in the paper. Those results provide further arguments for a closer relationship between fast oscillations and the BOLD signal, than between evoked potentials and the BOLD signal. PMID:14499000

  10. Reduced habituation to experimental pain in migraine patients: a CO(2) laser evoked potential study.

    PubMed

    Valeriani, M; de Tommaso, M; Restuccia, D; Le Pera, D; Guido, M; Iannetti, G D; Libro, G; Truini, A; Di Trapani, G; Puca, F; Tonali, P; Cruccu, G

    2003-09-01

    The habituation to sensory stimuli of different modalities is reduced in migraine patients. However, the habituation to pain has never been evaluated. Our aim was to assess the nociceptive pathway function and the habituation to experimental pain in patients with migraine. Scalp potentials were evoked by CO(2) laser stimulation (laser evoked potentials, LEPs) of the hand and facial skin in 24 patients with migraine without aura (MO), 19 patients with chronic tension-type headache (CTTH), and 28 control subjects (CS). The habituation was studied by measuring the changes of LEP amplitudes across three consecutive repetitions of 30 trials each (the repetitions lasted 5 min and were separated by 5-min intervals). The slope of the regression line between LEP amplitude and number of repetitions was taken as an index of habituation. The LEPs consisted of middle-latency, low-amplitude responses (N1, contralateral temporal region, and P1, frontal region) followed by a late, high-amplitude, negative-positive complex (N2/P2, vertex). The latency and amplitude of these responses were similar in both patients and controls. While CS and CTTH patients showed a significant habituation of the N2/P2 response, in MO patients this LEP component did not develop any habituation at all after face stimulation and showed a significantly lower habituation than in CS after hand stimulation. The habituation index of the vertex N2/P2 complex exceeded the normal limits in 13 out of the 24 MO patients and in none of the 19 CTTH patients (P<0.0001; Fisher's exact test). Moreover, while the N1-P1 amplitude showed a significant habituation in CS after hand stimulation, it did not change across repetitions in MO patients. In conclusion, no functional impairment of the nociceptive pathways, including the trigeminal pathways, was found in either MO or CTTH patients. But patients with migraine had a reduced habituation, which probably reflects an abnormal excitability of the cortical areas involved in pain processing. PMID:14499420

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

    PubMed Central

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

    2014-01-01

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

  12. Do pursuit movement tasks lead to differential changes in early somatosensory evoked potentials related to motor learning compared with typing tasks?

    PubMed

    Andrew, Danielle; Yielder, Paul; Murphy, Bernadette

    2015-02-15

    Central nervous system (CNS) plasticity is essential for development; however, recent research has demonstrated its role in pathology, particularly following overuse and repetition. Previous studies investigating changes in sensorimotor integration (SMI) have used relatively simple paradigms resulting in minimal changes in neural activity, as determined through the use of somatosensory evoked potentials (SEPs). This study sought to utilize complex tasks and compare separate motor paradigms to determine which one best facilitates long-term learning. Spinal, brainstem, and cortical SEPs were recorded following median nerve stimulation at the wrist pre- and postinterventions. Eighteen participants performed the same paradigms, a control condition of 10 min of mental recitation and two interventions, one consisting of 10 min of tracing and the other 10 min of repetitive typing. Significant increases in the N13, N20, P25, and N30 SEP peaks were seen for both interventions. A significant decrease in the N24 SEP peak was observed for both interventions. Significant improvements in accuracy were seen for both interventions postacquisition but only for tracing during retention. The changes seen following motor learning were congruent with those associated with long-term learning, which was also reflected by significant increases in accuracy during retention. Tracing or the pursuit movement paradigm was shown to be a more effective learning tool. The identification of a task that is sufficiently novel and complex, leading to robust changes in SEP peaks, indicates a task that can be utilized in future work to study clinical populations and the effect of experimental interventions on SMI. PMID:25429121

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

    Microsoft Academic Search

    Haim Ring; Leah Bar; Shimon Abboud

    1999-01-01

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

  14. Ocular Vestibular Evoked Myogenic Potentials in Response to Bone-Conducted Vibration of the Midline Forehead at Fz

    Microsoft Academic Search

    S. Iwasaki; Y. E. Smulders; A. M. Burgess; L. A. McGarvie; H. G. MacDougall; G. M. Halmagyi; I. S. Curthoys

    2008-01-01

    If a patient, who is lying supine and looking upward, is given bone-conducted vibration (BCV) of the forehead at the hairline in the midline (Fz) with a clinical reflex hammer or a powerful bone conduction vibrator, short-latency surface potentials called ocular vestibular evoked myogenic potentials (oVEMP) can be recorded from just beneath the eyes. The early negative (excitatory) component (n10)

  15. Sham TMS: intracerebral measurement of the induced electrical field and the induction of motor-evoked potentials

    Microsoft Academic Search

    Sarah H. Lisanby; David Gutman; Bruce Luber; Charles Schroeder; Harold A. Sackeim

    2001-01-01

    %Testing the therapeutic potential of transcranial magnetic stimulation (TMS) in controlled trials requires a valid sham condition. Sham TMS is typically administered by tilting the coil 45–90° off the scalp, with one or two wings of the coil touching the scalp. Lack of cortical effects has not been verified. mWe compared sham manipulations in their thresholds for eliciting motor-evoked potentials

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

    EPA Science Inventory

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

  17. Enhancement of Evoked Cortical Potentials in Humans Related to a Task Requiring a Decision

    Microsoft Academic Search

    Hallowell Davis

    1964-01-01

    The averaged, slow response evoked by auditory stimuli and recorded from the vertex of the human skull can usually be enhanced by requiring the listener to make a rather difficult auditory discrimination. An easy routine reaction is not effective.

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

    NASA Technical Reports Server (NTRS)

    Johnston, V. S.

    1975-01-01

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

  19. Nicotine Receptor Subtype-Specific Effects on Auditory Evoked Oscillations and Potentials

    PubMed Central

    Featherstone, Robert E.; Phillips, Jennifer M.; Thieu, Tony; Ehrlichman, Richard S.; Halene, Tobias B.; Leiser, Steven C.; Christian, Edward; Johnson, Edwin; Lerman, Caryn; Siegel, Steven J.

    2012-01-01

    Background Individuals with schizophrenia show increased smoking rates which may be due to a beneficial effect of nicotine on cognition and information processing. Decreased amplitude of the P50 and N100 auditory event-related potentials (ERPs) is observed in patients. Both measures show normalization following administration of nicotine. Recent studies identified an association between deficits in auditory evoked gamma oscillations and impaired information processing in schizophrenia, and there is evidence that nicotine normalizes gamma oscillations. Although the role of nicotine receptor subtypes in augmentation of ERPs has received some attention, less is known about how these receptor subtypes regulate the effect of nicotine on evoked gamma activity. Methodology/Principal Findings We examined the effects of nicotine, the ?7 nicotine receptor antagonist methyllycaconitine (MLA) the ?4?4/?4?2 nicotine receptor antagonist dihydro-beta-erythroidine (DH?E), and the ?4?2 agonist AZD3480 on P20 and N40 amplitude as well as baseline and event-related gamma oscillations in mice, using electrodes in hippocampal CA3. Nicotine increased P20 amplitude, while DH?E blocked nicotine-induced enhancements in P20 amplitude. Conversely, MLA did not alter P20 amplitude either when presented alone or with nicotine. Administration of the ?4?2 specific agonist AZD3480 did not alter any aspect of P20 response, suggesting that DH?E blocks the effects of nicotine through a non-?4?2 receptor specific mechanism. Nicotine and AZD3480 reduced N40 amplitude, which was blocked by both DH?E and MLA. Finally, nicotine significantly increased event-related gamma, as did AZD3480, while DH?E but not MLA blocked the effect of nicotine on event-related gamma. Conclusions/Significance These results support findings showing that nicotine-induced augmentation of P20 amplitude occurs via a DH?E sensitive mechanism, but suggests that this does not occur through activation of ?4?2 receptors. Event-related gamma is strongly influenced by activation of ?4?2, but not ?7, receptor subtypes, while disruption of N40 amplitude requires the activation of multiple receptor subtypes. PMID:22911690

  20. Stimulus and recording variables and their effects on mammalian vestibular evoked potentials

    NASA Technical Reports Server (NTRS)

    Jones, Sherri M.; Subramanian, Geetha; Avniel, Wilma; Guo, Yuqing; Burkard, Robert F.; Jones, Timothy A.

    2002-01-01

    Linear vestibular evoked potentials (VsEPs) measure the collective neural activity of the gravity receptor organs in the inner ear that respond to linear acceleration transients. The present study examined the effects of electrode placement, analog filtering, stimulus polarity and stimulus rate on linear VsEP thresholds, latencies and amplitudes recorded from mice. Two electrode-recording montages were evaluated, rostral (forebrain) to 'mastoid' and caudal (cerebellum) to 'mastoid'. VsEP thresholds and peak latencies were identical between the two recording sites; however, peak amplitudes were larger for the caudal recording montage. VsEPs were also affected by filtering. Results suggest optimum high pass filter cutoff at 100-300 Hz, and low pass filter cutoff at 10,000 Hz. To evaluate stimulus rate, linear jerk pulses were presented at 9.2, 16, 25, 40 and 80 Hz. At 80 Hz, mean latencies were longer (0.350-0.450 ms) and mean amplitudes reduced (0.8-1.8 microV) for all response peaks. In 50% of animals, late peaks (P3, N3) disappeared at 80 Hz. The results offer options for VsEP recording protocols. Copyright 2002 Elsevier Science B.V.

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

    PubMed Central

    Kang, Jun Il; Vaucher, Elvire

    2009-01-01

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

  2. Topographic components analysis of evoked potentials: estimation of model parameters and evaluation of parameter uniqueness.

    PubMed

    Field, A; Graupe, D

    1990-07-01

    The purpose of this paper is to evaluate the practicability of the 'topographic components model' proposed by Möcks for the spatio-temporal characterization of multi-channel evoked potentials (EP), and to present a complete and detailed algorithm for this method of analysis. Details of the algorithm are discussed along with various computational issues, especially with regard to contrasts with traditional principal components analysis. The algorithm is applied to multi-channel pattern-shift visual EP data obtained from normal subjects, and the model is demonstrated to provide data reduction of 71% with a relative mean-squared error (MSE) of 2%. Obvious features of the data are seen to be reflected in the estimated model parameters, lending support to the appropriateness of the model. The results also demonstrate that although the model parameters are uniquely identifiable in theory, care must be taken when fitting the model to insure that the MSE is not so insensitive to perturbations in the model parameters that they are rendered 'non-unique' for all practical purposes. The proper selection of model order is shown to play a critical role in avoiding this problem. Finally, a theoretical analysis is presented which evaluates the relationship between parameter 'uniqueness', model order, and the non-orthogonality of the model components. PMID:2395355

  3. Eliciting steady-state visual evoked potentials by means of stereoscopic displays

    NASA Astrophysics Data System (ADS)

    Calore, Enrico; Gadia, Davide; Marini, Daniele

    2014-03-01

    Brain-Computer Interfaces (BCIs) provide users communication and control capabilities by analyzing their brain activity. A technique to implement BCIs, used recently also in Virtual Reality (VR) environments, is based on the Steady State Visual Evoked Potentials (SSVEPs) detection. Exploiting the SSVEP response, BCIs could be implemented showing targets flickering at different frequencies and detecting which is gazed by the observer analyzing her/his electroencephalographic (EEG) signals. In this work, we evaluate the use of stereoscopic displays for the presentation of SSVEP eliciting stimuli, comparing their effectiveness between monoscopic and stereoscopic stimuli. Moreover we propose a novel method to elicit SSVEP responses exploiting the stereoscopic displays capability of presenting dichoptic stimuli. We have created an experimental scene to present flickering stimuli on an active stereoscopic display, obtaining reliable control of the targets' frequency independently for the two stereo views. Using an EEG acquisition device, we analyzed the SSVEP responses from a group of subjects. From the preliminary results, we got evidence that stereoscopic displays represent valid devices for the presentation of SSVEP stimuli. Moreover, the use of different flickering frequencies for the two views of a single stimulus proved to elicit non-linear interactions between the stimulation frequencies, clearly visible in the EEG signal. This suggests interesting applications for SSVEP-based BCIs in VR environments able to overcome some limitations imposed by the refresh frequency of standard displays, but also the use of commodity stereoscopic displays to implement binocular rivalry experiments.

  4. Human high frequency somatosensory evoked potential components are refractory to circadian modulations of tonic alertness.

    PubMed

    Gobbelé, René; Waberski, Till D; Thyerlei, Dinah; Thissen, Melanie; Fimm, Bruno; Klostermann, Fabian; Curio, Gabriel; Buchner, Helmut

    2007-02-01

    The impact of vigilance states, such as sleep or arousal changes, on the high-frequency (600 Hz) components (HFOs) of somatosensory evoked potentials (SEPs) is known. The present study sought to characterize the effects of circadian fluctuations of tonic alertness on HFOs in awake humans. Median nerve SEPs were recorded at four times during a 24-hour waking period. In parallel to the SEP recordings, a reaction-time (RT) task was performed to assess tonic alertness. Additionally, the spontaneous EEG was monitored. The low-frequency SEP component N20 and the early and late HFO parts did not change across the measurement sessions. In contrast, RTs were clearly prolonged at night and on the second morning. EEG also showed increased delta power at night. HFOs are sensitive to pronounced vigilance changes, such as sleep, but are refractory to fluctuations of tonic alertness. Tonic alertness is regarded to be the top-down cognitive control mechanism of wakefulness, whereas sleep is mediated by overwhelming bottom-up regulation, which seems apparently more relevant for, at least in part, subcortically triggered high-frequency burst generation in the ascending somatosensory system. PMID:17277574

  5. Within-session changes in peak N160 amplitude of flash evoked potentials in rats.

    PubMed

    Herr, D W; King, D; Griffin, V T; Watkinson, W P; Boyes, W K; Ali, J S; Dyer, R S

    1994-01-01

    The negative peak occurring approximately 160 ms after stimulation (peak N160) of flash evoked potentials (FEPs) of rats changes with repeated testing. Habituation, sensitization, and arousal have all been invoked to explain these changes, but few studies have directly tested these explanations. We examined within-session changes in peak N160 amplitude with repeated testing, and the modulatory effects of stimulus intensity and auditory white noise. Peak N160 amplitude increased with daily testing (between-session changes), and was larger at greater stimulus intensities. In contrast, peak N160 amplitude underwent within-session increases on early days and within-session decreases on later days. The within-session changes were not affected by stimulus intensity. In rats previously tested in a quiet environment, exposure to acoustic white noise increased motor activity and transiently decreased peak N160 amplitude, which then increased and subsequently decreased with continued photic and acoustic stimulation. Repeated testing in the presence of noise did not alter the within-session changes in peak N160 amplitude. Heart rate showed both within- and between-session decreases, but was unaffected by noise. The data suggest that the within-session changes in peak N160 amplitude may reflect a habituation-like response to the test environment. PMID:8140179

  6. Nicotine alters flash-evoked potentials in Long-Evans rats.

    PubMed

    Hetzler, Bruce E; Theinpeng, Maraty

    2004-04-01

    This experiment examined the effects of nicotine on flash-evoked potentials (FEPs) recorded from both the visual cortex (VC) and the superior colliculus (SC) of chronically implanted male Long-Evans rats. FEPs were recorded at 5, 20, 40, and 60 min following subcutaneous injections of saline, and of 0.4, 0.7, and 1.0 mg/kg nicotine on separate days. In the VC, the amplitude of components N(39), N(53), N(67), and P(88) increased, while the amplitude of components N(30) and P(235) decreased following nicotine administration. P(22), P(47), and N(153) were unchanged. In the SC, components P(27), N(48), and N(53) were reduced in amplitude, while P(37) and N(57) were unaffected by nicotine. Many peak latencies in the VC and SC were increased by nicotine, often at all three doses. However, effects of nicotine on FEPs were both dose- and time-dependent. When body temperature was recorded 65 min after drug administration, significant hypothermia was found with both the 0.7- and 1.0-mg/kg nicotine doses. The 1.0-mg/kg dose of nicotine resulted in a significant increase in movement during the recording sessions, but not in subsequent open-field observations. The results demonstrate that nicotinic acetylcholine receptors (nAChRs) play a differential role in the production/modulation of the various components of FEPs. PMID:15099917

  7. Baclofen alters flash-evoked potentials in Long-Evans rats.

    PubMed

    Hetzler, Bruce E; Ondracek, Janie M

    2007-04-01

    This experiment examined the effects of the GABA-B agonist baclofen on flash-evoked potentials (FEPs) recorded from both the visual cortex (VC) and superior colliculus (SC) of chronically implanted male Long-Evans rats. FEPs were recorded at 5, 25, 45, and 65 min following intraperitoneal injections of saline, and of 1.25, 2.5, 5.0, and 10.0 mg/kg baclofen on separate days. In the VC, the amplitude of components P(23), P(37), N(55), N(150), and P(242) increased, while the amplitude of components N(31) and P(48) decreased following baclofen administration. P(88) was unchanged. In the SC, components P(28), N(49), N(55), and N(59) were reduced in amplitude, while P(39) was unaffected by baclofen. These effects on amplitudes were dose- and time-dependent. Many peak latencies in the VC and SC were altered by baclofen, although there was no obvious pattern of change, with some decreasing, a few increasing, and others unchanged. Body temperature was recorded in a separate group of animals, with both the 5.0 and 10.0 mg/kg doses of baclofen producing significant hypothermia. The 10.0 mg/kg dose of baclofen resulted in a significant decrease in movement during the recording sessions, but not in subsequent open field observations. The results show the involvement of GABA-B receptors in the production/modulation of the various components of FEPs. PMID:17407791

  8. Vestibular-evoked myogenic potential in response to bone-conducted sound in patients with otosclerosis

    PubMed Central

    Seo, Toru; Fujimori, Kiyoko; Mishiro, Yasuo; Sakagami, Masafumi

    2012-01-01

    Conclusion: Saccular dysfunction is a major cause of balance problems in patients with otosclerosis. Vestibular-evoked myogenic potential in response to bone-conducted sound (BC-VEMP) testing is useful for diagnosis of these patients. Objectives: The purpose of this study was to elucidate the origin of balance problems in patients with otosclerosis using BC-VEMP. Methods: Subjects comprised 25 patients with unoperated otosclerosis (9 men and 16 women). They were divided into two groups depending on type of balance problems. Results of cochleo-vestibular functions including pure-tone audiometry, caloric testing, and BC-VEMP testing were compared between the two groups. Results: Ten patients had complained of dizziness and/or vertigo (disequilibrium group), and the other 15 patients had not (Non-disequilibrium group). Nine patients showed abnormal results on BC-VEMP testing in the disequilibrium group, while one patient had abnormal results in the non-disequilibrium group (p < 0.001). PMID:22830649

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

    PubMed

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

    2014-11-27

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

  10. Preservation of tap vestibular evoked myogenic potentials despite resection of the inferior vestibular nerve.

    PubMed

    Brantberg, Krister; Mathiesen, Tiit

    2004-01-01

    Sound and skull-tap induced vestibular evoked myogenic potentials (VEMP) were studied in a 43-year-old man following inferior vestibular neurectomy. Surgery was performed because of a small acoustic neuroma. Postoperative caloric testing suggested sparing of superior vestibular nerve function on the operated side. In response to sound stimulation there were no VEMP on the operated side, irrespective of whether sounds were presented by air- or bone-conduction. This suggests sound-induced VEMP to be critically dependent on inferior vestibular nerve function and this is in agreement with present knowledge. However, VEMP were obtained in response to forehead skull taps, i.e. positive-negative VEMP not only on the healthy side but also on the operated side. This suggests remnant vestibular function on the operated side of importance for forehead skull tap VEMP, because with complete unilateral vestibular loss there are no (positive-negative) VEMP on the lesioned side. Thus, forehead skull-tap VEMP depend, at least partly, on the superior vestibular nerve function. PMID:15328448

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

    PubMed

    Brighina, Filippo; Palermo, Antonio; Fierro, Brigida

    2009-04-01

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

  12. Factors affecting the stimulus artifact tail in surface-recorded somatosensory-evoked potentials.

    PubMed

    Hua, Y; Lovely, D F; Doraiswami, R

    2006-03-01

    Surface-recorded somatosensory-evoked potentials (SEPs) are neural signals elicited by an external stimulus. In the case of electrically induced SEPs, the artifact generated by the stimulation process can severely distort the signal. In some cases, the artifact tail often lasts well into the initiation of the SEP making the determination of absolute latency very difficult. In this work, a new approach was taken to identify factors that affect the tail of the artifact. The methodology adopted was the development of a lumped electrical circuit model of the artifact generation process. While the modeling of the instrumentation hardware is relatively simple, this is not the case with tissue and electrode/skin interface effects. Consequently, this paper describes a novel tissue modeling approach that uses an autoregressive moving average (ARMA) parametric technique and an artificial neural network (ANN) to estimate tissue parameters from experimental data. This coupled with an estimation of the stimulation electrode-skin impedance completes the lumped circuit model. Simulink (The Mathworks Inc.) was used to evaluate the model under several different conditions. These results show that both the stimulation electrode-skin interface impedance and nature of the body tissue directly under the recording electrodes have a profound effect on the appearance of the stimulus artifact tail. This was verified by experimentally recorded data obtained from the median nerve using surface electrodes. Conclusions drawn from this work include that stimulation electrodes with low series capacitance should be used whenever possible to minimize the duration of the artifact tail. PMID:16937164

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

    PubMed Central

    2014-01-01

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

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

    PubMed

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

    2012-01-01

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

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

    PubMed

    Itoh, Kosuke; Suwazono, Shugo; Nakada, Tsutomu

    2010-12-01

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

  16. Effects of stimulus intensity on posterior tibial nerve somatosensory evoked potentials.

    PubMed

    Rappaport, M; Ruiz Portillo, S; Leonard, J

    1992-04-01

    Relationships between stimulus intensity and peak latencies and amplitudes in posterior tibial nerve somatosensory evoked potential patterns were evaluated in ten healthy subjects. Eight intermediate latency peaks between 30 and 125 milliseconds (ms) after stimulus onset and seven amplitudes were analyzed. In general, there was a decrease in latency with each increase in stimulus intensity over a five step intensity range between 5 and 19 milliamps (mA) for most peaks. Similarly, increases in amplitudes generally occurred with increases in stimulus intensity for most peaks. Later peaks N105 and P115 as well as amplitudes P90-N105 and N105-P115 were least sensitive to stimulus intensity changes. The greatest changes in peak latency and amplitude occurred as stimulus intensity was increased from 7 to 11 mA. Beyond 11 mA relatively little change was observed in either peak latencies or amplitudes. Under anesthesia, by contrast, there was no stimulus intensity-peak latency interaction and beyond 11 mA there were decreases in amplitudes. Possible reasons for these findings are discussed. PMID:1582054

  17. The role of somatosensory evoked potentials in the diagnosis of lumbosacral radiculopathies.

    PubMed

    Beyaz, E Arikan; Akyüz, G; Us, O

    2009-01-01

    Electrophysiologic studies have an important role in the diagnosis of lumbosacral radiculopathies. Electrophysiologic methods which are used conventionally are needle electromyography (EMG), late responses (F wave and H reflex), and nerve conduction studies. Somatosensory evoked potentials (SEPs) are also important complementary diagnostic methods in the electrophysiologic evaluation of lumbosacral radiculopathies. In this study, we aimed to determine whether SEPs have an advantage over the conventional electrophysiologic methods or whether sensory nerve stimulated SEPs over mixed nerve stimulated ones or the lumbar recordings over the scalp recordings in diagnosing lumbosacral radiculopathies. For this reason, the study included 20 patients with unilateral and unilevel S1 radiculopathy due to intervertebral disc herniation confirmed by clinical examination and magnetic resonance imaging (MRI) as the patient group. And a control group of 18 healthy subjects were also included in the study. Nerve conduction studies, late responses and scalp and lumbar-recorded SEPs after sural and posterior tibial nerve stimulation were studied in both groups, while needle EMG was performed only in the patient group. Patients who manifested abnormal findings on needle EMG or on late responses also showed abnormal findings on at least one type of the SEPs. SEPs detected abnormalities in 5 patients (25%) in whom needle EMG or late responses did not suggest any abnormality. In this study we concluded that SEPs may provide diagnostic information beyond conventional electrodiagnostic methods and that lumbar-recorded SEPs may have an advantage over scalp-recorded ones and sensory nerve stimulated SEPs over mixed nerve stimulated ones. PMID:19534290

  18. Intraoperative Monitoring of Motor-Evoked Potentials for Supratentorial Tumor Surgery

    PubMed Central

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

    2014-01-01

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

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

    PubMed

    Tavartkiladze, George; Bakhshinyan, Vigen; Irwin, Colin

    2014-12-01

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

  20. Short-term food deprivation increases amplitudes of heartbeat-evoked potentials.

    PubMed

    Schulz, André; Ferreira de Sá, Diana S; Dierolf, Angelika M; Lutz, Annika; van Dyck, Zoé; Vögele, Claus; Schächinger, Hartmut

    2015-05-01

    Nutritional state (i.e., fasting or nonfasting) may affect the processing of interoceptive signals, but mechanisms underlying this effect remain unclear. We investigated 16 healthy women on two separate days: when satiated (standardized food intake) and after an 18-h food deprivation period. On both days, heartbeat-evoked potentials (HEPs) and cardiac and autonomic nervous system activation indices (heart rate, normalized low frequency heart rate variability [nLF HRV]) were assessed. The HEP is an EEG pattern that is considered an index of cortical representation of afferent cardiovascular signals. Average HEP activity (R wave +455-595?ms) was enhanced during food deprivation compared to normal food intake. Cardiac activation did not differ between nutritional conditions. Our results indicate that short-term food deprivation amplifies an electrophysiological correlate of the cortical representation of visceral-afferent signals originating from the cardiovascular system. This effect could not be attributed to increased cardiac activation, as estimated by heart rate and nLF HRV, after food deprivation. PMID:25431244

  1. Brain evoked potentials to noxious sural nerve stimulation in sciatalgic patients.

    PubMed

    Willer, J C; De Broucker, T; Barranquero, A; Kahn, M F

    1987-07-01

    In sciatalgic patients and before any treatment, the goal of this work was to compare the amplitude of the late component (N150-P220) of the brain evoked potential (BEP) between resting pain-free conditions and a neurological induced pain produced by the Lasègue manoeuvre. The study was carried out with 8 inpatients affected with a unilateral sciatica resulting from an X-ray identified dorsal root compression from discal origin. The sural nerve was electrically stimulated at the ankle level while BEPs were recorded monopolarly from the vertex. The stimulus intensity eliciting a liminal nociceptive reflex response in a knee-flexor muscle associated with a liminal pain was selected for this study. Both normal and affected side were alternatively stimulated during several conditions of controls and of Lasègue's manoeuvres performed on the normal and on the affected side. Results show that the Lasègue manoeuvre performed on the affected side induced a significant increase in the amplitude of N150-P220; performed on the normal side, this same manoeuvre resulted in a significant decrease of the N150-P220 amplitude. These variations were observed whatever was the side (normal or affected) under sural nerve stimulation. The possible neural mechanisms of these changes and clinical implications of these data are then discussed. PMID:3614979

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

    PubMed

    Kevanishvili, Z; Lagidze, Z

    1979-01-01

    Amplitude reduction and peak latency prolongation were observed in the human brain stem auditory-evoked potential (BEP) with preceding (conditioning) stimulation. At a conditioning interval (CI) of 5 ms the alteration of BEP was greater than at a CI of 10 ms. At a CI of 10 ms the amplitudes of some BEP components (e.g. waves I and II) were more decreased than those of others (e.g. wave V), while the peak latency prolongation did not show any obvious component selectivity. At a CI of 5 ms, the extent of the amplitude decrement of individual BEP components differed less, while the increase in the peak latencies of the later components was greater than that of the earlier components. The alterations of the parameters of the test BEPs at both CIs are ascribed to the desynchronization of intrinsic neural events. The differential amplitude reduction at a CI of 10 ms is explained by the different durations of neural firings determining various effects of desynchronization upon the amplitudes of individual BEP components. The decrease in the extent of the component selectivity and the preferential increase in the peak latencies of the later BEP components observed at a CI of 5 ms are explained by the intensification of the mechanism of the relative refractory period. PMID:526192

  3. Dorsolateral medullary infarction: a neurogenic cause of a contralateral, large-amplitude vestibular evoked myogenic potential.

    PubMed

    Lundy, Larry; Zapala, David; Olsholt, Ketil

    2008-03-01

    The vestibular evoked myogenic potential (VEMP) has become a useful tool to assess the saccule and inferior vestibular nerve function. Vestibulopathies involving the saccule or inferior vestibular nerve typically result in VEMP responses that are diminished or absent on the involved side. Abnormally large VEMPs are rare. Large VEMPs have been associated with superior canal dehiscence, Ménière's disease, and labyrinthine fistula. In all of these cases, the abnormally large VEMP can be explained on the basis of labyrinthine hydromechanical changes that result in excessive saccular displacement in response to intense sound. In this report, a case is presented of a 74-year-old male with dorsal lateral medullary infarction (Wallenberg's syndrome) who presented with an enlarged VEMP--a finding that has not been reported to date as a result of a brain stem lesion. Particularly perplexing, the enlarged VEMP was on the contralesional side. A proposed mechanism of contralateral vestibular nuclei disinhibition secondary to the brain stem stroke is discussed. PMID:18672653

  4. Analysis of the visual evoked potential in anesthesia with sevoflurane and chloral hydrate

    PubMed Central

    Ghita, AM; Parvu, D; Sava, R; Georgescu, L; Zagrean, L

    2013-01-01

    The visually evoked potential (VEP) is an electrical signal generated by the occipital cortex in response to light stimulation of the retina. The clinical importance of the VEP consists in the diagnosis of optic nerve diseases and others ocular diseases. For experimental studies of VEP in experimental animals anesthesia is frequently required. Our study sought VEP changes depending on the type and depth of anesthesia. Methods: this study evaluated VEPs in 20 Wistar rats under two anesthetics. Ten rats were anesthetized with sevoflurane and ten rats with chloral hydrate. Results: The amplitudes, latencies and morphology of the VEP varied with the depth of anesthesia. The latency of VEP increases with the depth of anesthesia and the amplitude of the waves becomes more positive once the anesthesia decreases under sevoflurane and more negative under chloral hydrate. The variability of VEP was different under the two anesthetics with greater peak latencies under sevoflurane than under chloral hydrate at the same depth of anesthesia. In conclusion: it is important to know the influence of the anesthetic and the depth of anesthesia over VEPS, because they may constitute a confounding factor in studying VEP in different diseases of optic nerve or eyeball. PMID:23904886

  5. Abnormalities of coherent motion processing in strabismic amblyopia: Visual Evoked Potential measurements

    PubMed Central

    Hou, C.; Pettet, M.W.; Norcia, A.M.

    2015-01-01

    Coherent motion responses of patients with mild to moderate strabismic amblyopia were compared to those of normals using Visual Evoked Potentials (VEPs). Responses were elicited by dynamic random dot kinematograms that alternated at 0.83 Hz between globally coherent (left-right) and incoherent (random) motion states. Tuning curves were measured at the first harmonic of the global motion update rate (0.83 Hz) and at the first harmonic of the dot update rate (20 Hz) for spatial displacements 3.1 to 27.9 arc min (1.6 to 9.3 deg/s). Responses locked to the changes in the global organization of the local direction vectors were an inverted U-shaped function of displacement/speed in the normal-vision observers and in the fellow eyes of the strabismus patients while the tuning function of the amblyopic eyes was shifted to larger displacements/higher speeds. Responses at the dot update rate were reduced in amplitude and altered in timing in both eyes of the patients. The results are consistent with both local and global deficits in motion processing in strabismic amblyopia. PMID:18484841

  6. Multidimensional scaling of schematically represented faces based on dissimilarity estimates and evoked potentials of differences amplitudes.

    PubMed

    Izmailov, Chingiz A; Sokolov, Evgeni N; Korshunova, Svetlana G

    2005-11-01

    This study researches the input of the cerebral occipital and temporal cortex in the analysis of facial configuration and expressive characteristics. Analysis is based on the construction of a spherical model for the differentiation of schematically presented faces with quantitatively altering curvature of the mouth and brows. The model is designed using the method of multidimensional scaling of the dissimilarity judgments between stimuli (faces) and the amplitude of evoked potentials of differences (EPD) between abrupt stimulus changes recorded from the occipital and posterior temporal cortex. Analysis of the structure of the spherical model of facial differentiation depending on the electrode site and the latency of the EPD component within the duration of 120-240 ms has demonstrated that the activity of the occipital and posterior temporal cortex of the right hemisphere is associated with the emotional characteristics of the presented face, whereas facial configuration is reflected in the activation of both posterior temporal cortex and the occipital cortex of the left hemisphere. At all electrode sites maximum information of the emotional expression and configuration is represented in inter-peak amplitude P120-N180. With increasing latency there is increased distortion of the structure of differences in the spherical model of schematically presented faces, which is interpreted as an attenuation of electrical activity associated with the analysis of the emotional expression, which occurs more rapidly than configuration analysis. PMID:16255381

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

    PubMed

    Bestmann, Sven; Krakauer, John W

    2015-03-01

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

  8. EEG-based classification of video quality perception using steady state visual evoked potentials (SSVEPs)

    NASA Astrophysics Data System (ADS)

    Acqualagna, Laura; Bosse, Sebastian; Porbadnigk, Anne K.; Curio, Gabriel; Müller, Klaus-Robert; Wiegand, Thomas; Blankertz, Benjamin

    2015-04-01

    Objective. Recent studies exploit the neural signal recorded via electroencephalography (EEG) to get a more objective measurement of perceived video quality. Most of these studies capitalize on the event-related potential component P3. We follow an alternative approach to the measurement problem investigating steady state visual evoked potentials (SSVEPs) as EEG correlates of quality changes. Unlike the P3, SSVEPs are directly linked to the sensory processing of the stimuli and do not require long experimental sessions to get a sufficient signal-to-noise ratio. Furthermore, we investigate the correlation of the EEG-based measures with the outcome of the standard behavioral assessment. Approach. As stimulus material, we used six gray-level natural images in six levels of degradation that were created by coding the images with the HM10.0 test model of the high efficiency video coding (H.265/MPEG-HEVC) using six different compression rates. The degraded images were presented in rapid alternation with the original images. In this setting, the presence of SSVEPs is a neural marker that objectively indicates the neural processing of the quality changes that are induced by the video coding. We tested two different machine learning methods to classify such potentials based on the modulation of the brain rhythm and on time-locked components, respectively. Main results. Results show high accuracies in classification of the neural signal over the threshold of the perception of the quality changes. Accuracies significantly correlate with the mean opinion scores given by the participants in the standardized degradation category rating quality assessment of the same group of images. Significance. The results show that neural assessment of video quality based on SSVEPs is a viable complement of the behavioral one and a significantly fast alternative to methods based on the P3 component.

  9. Effects of multiple doses of organophosphates on evoked potentials in mouse diaphragm.

    PubMed

    Kelly, S S; de Blaquière, G E; Williams, F M; Blain, P G

    1997-02-01

    1. Male albino mice were injected s.c. with an organophosphate (mipafox, ecothiopate or paraoxon). Treatments were either a single injection or multiple daily injections with lower doses for 5 or 8 days. At 3 h after injection the activity of brain and diaphragm acetylcholinesterase and of brain neuropathy target esterase (NTE) was measured. Also measured in the diaphragm at 3 h post dose was the duration of spontaneous miniature endplate potentials (eMEPPs), recorded extracellularly. 2. At 7 and 28 days after dosing action potentials and evoked endplate potentials, produced by stimulating the phrenic nerve at 30 Hz, were recorded in diaphragm muscle. The amplitudes, time-course and latencies of these potentials were measured and the variability of latencies (jitter) was calculated. 3. Single doses of mipafox (20 mg/kg), ecothiopate (0.192 mg/kg) or paraoxon (0.415 mg/kg) in the mouse produced ca. 70% inhibition of diaphragm acetylcholinesterase at 3 h after dosing. All three OPs produced a prolongation of the half-decay times of eMEPPs. 4. All three OPs in the above single doses produced increased muscle action potential (postjunctional) jitter but only mipafox produced an increase in endplate potential (prejunctional) jitter. Mipafox in a slightly reduced single dose (17.5 mg/kg) had no effect on prejunctional or postjunctional jitter. 5. Multiple dosing with mipafox (8 mg/kg daily for 5 days) increased both postjunctional and prejunctional jitter at both 7 and 28 days after the end of dosing. After multiple dosing with mipafox (5 mg/kg daily for 5 days) postjunctional (but not prejunctional) jitter was increased. Multiple doses of paraoxon (0.166 mg/kg daily for 5 days) or ecothiopate (0.76 mg/kg daily for 5 days) increased prejunctional and postjunctional jitter. 6. Depending on the dosing regime, all three OPs tested were capable of increasing both prejunctional and postjunctional jitter. Neither ecothiopate nor paraoxon inhibited NTE, so this prejunctional effect is not likely to be related to 'classical' OP-induced delayed neuropathy. The prejunctional effects may be related to long-term inhibition of acetylcholinesterase and the triggering mechanism for increase in prejunctional jitter may involve a relationship between the inhibition of acetylcholinesterase and the time for which it is inhibited. The differences between the time-courses of increases in prejunctional and postjunctional jitter and the differential effects of the different multiple dosing regimes indicate that it is likely that the triggering relationship between enzyme inhibition and time is different for prejunctional and postjunctional effects. PMID:9051411

  10. Nerve-evoked constriction of rat tail veins is potentiated and venous diameter is reduced after chronic spinal cord transection.

    PubMed

    Tripovic, Diana; Al Abed, Amr; Rummery, Nicole M; Johansen, Niloufer J; McLachlan, Elspeth M; Brock, James A

    2011-05-01

    Despite reduced sympathetic activity below the level of a spinal cord injury (SCI), venoconstriction during autonomic dysreflexia increases venous return to the heart. Here, contractions of isometrically mounted tail veins from rats with spinal transection at T4 performed 8?-?10 weeks earlier are compared with those from sham-operated rats. After SCI, lumen diameter was reduced by ?30% and the contractions evoked by electrical stimulation of the perivascular axons were larger than control. This augmentation of neurovascular transmission was not associated with enhanced sensitivity to ?-adrenoceptor agonists or to adenosine-5'-triphosphate (ATP) although contractions to depolarization with K(+) were larger after SCI. The percentage reduction in nerve-evoked contraction after SCI produced by the ?(1)-adrenoceptor antagonist prazosin (10?nM) was unchanged but that by the ?(2)-adrenoceptor antagonist rauwolscine (0.1??M) was reduced. The relative contribution of P2-purinoceptors to nerve-evoked contractions after ?-adrenoceptor blockade, revealed by adding suramin (0.1?mM), was unchanged. The greater depolarization-induced contraction and the reduced contribution of ?(2)-adrenoceptors to nerve-evoked contraction suggest that changes in the venous smooth muscle underlie the potentiation of neurovascular transmission after SCI. Furthermore, the smaller lumen diameter after SCI will increase the pressure that the veins exert on the luminal contents when they are neurally activated. PMID:21222499

  11. Short-latency auditory evoked potentials in the monkey. II. Intracranial generators.

    PubMed

    Legatt, A D; Arezzo, J C; Vaughan, H G

    1986-07-01

    The generators of the short-latency auditory evoked potentials (SLAEPs) in the monkey have been defined by intracranial mapping from cochlea to auditory cortex. SLAEP components other than 1a and the slow negativity (SN) following wave 7 derive from compound action potentials propagated in subcortical auditory pathways. The component generators are complex due to the presence of two bursts of activity in the eighth nerve, to the fact that the ascending auditory fibers both synapse on and bypass specific relay nuclei, and to the differences in orientation of segments of the auditory pathways. Most SLAEP components recorded at the surface reflect the summation of activity from multiple generators. However, much of the activity seen within subcortical structures cannot be traced to the surface of the brain. Component 1a is identified with the cochlear summating potential, while 1b reflects the initial afferent volley in the distal portion of the eighth nerve. Component 2 represents the initial depolarization of the eighth nerve terminals within the ipsilateral cochlear nucleus. Component 3h reflects the second volley of activity in the distal portion of the eighth nerve and the outflow of the cochlear nucleus which decussates in the trapezoid body. Component 3v represents the initial cochlear nucleus outflow volley ascending the lateral lemniscus. Component 4 principally reflects the second volley of activity within the eighth nerve terminals, and outflow from the ipsilateral superior olivary complex ascending in that lateral lemniscus, with a possible contribution from activity in the contralateral CNC. Component 5 represents the outflow of the contralateral superior olivary complex ascending in that lateral lemniscus. Component 6 reflects another volley from the ipsilateral superior olivary complex ascending in that lateral lemniscus, as well as outflow from both inferior colliculi propagating in their brachii. The generators of component 7 are the most complex encountered, representing volleys in both lateral lemnisci, activity of the contralateral inferior colliculus, and activity in both auditory radiations. A component that follows wave 7, seen best in mastoid-to-mastoid recording linkage, represents outflow from both inferior colliculi propagating in their brachia. Components 8 and 9 principally reflect propagated action potentials in the auditory radiations bilaterally, with an additional contribution from activity of both inferior colliculi. The SN mainly represents volume-conducted postsynaptic potentials from both inferior colliculi and cochlear nuclei. PMID:2424722

  12. Listening to the brainstem: musicianship enhances intelligibility of subcortical representations for speech.

    PubMed

    Weiss, Michael W; Bidelman, Gavin M

    2015-01-28

    Auditory experiences including musicianship and bilingualism have been shown to enhance subcortical speech encoding operating below conscious awareness. Yet, the behavioral consequence of such enhanced subcortical auditory processing remains undetermined. Exploiting their remarkable fidelity, we examined the intelligibility of auditory playbacks (i.e., "sonifications") of brainstem potentials recorded in human listeners. We found naive listeners' behavioral classification of sonifications was faster and more categorical when evaluating brain responses recorded in individuals with extensive musical training versus those recorded in nonmusicians. These results reveal stronger behaviorally relevant speech cues in musicians' neural representations and demonstrate causal evidence that superior subcortical processing creates a more comprehensible speech signal (i.e., to naive listeners). We infer that neural sonifications of speech-evoked brainstem responses could be used in the early detection of speech-language impairments due to neurodegenerative disorders, or in objectively measuring individual differences in speech reception solely by listening to individuals' brain activity. PMID:25632143

  13. Intraoperative Myogenic Motor Evoked Potentials Induced by Direct Electrical Stimulation of the Exposed Motor Cortex Under Isoflurane and Sevoflurane

    Microsoft Academic Search

    Masahiko Kawaguchi; Takanori Sakamoto; Hideyuki Ohnishi; Kiyoshi Shimizu; Jun Karasawa; Hitoshi Furuya

    1996-01-01

    We monitored myogenic motor evoked potentials (MEPs) during intracranial surgery in 21 patients anes- thetized with nitrous oxide in oxygen, fentanyl, and 0.75-1.5 minimum alveolar anesthetic concentration (MAC) isoflurane (n = 11) or sevoflurane (n = 10). The exposed motor cortex was stimulated with a single or train-of-five rectangular pulses at a high frequency (500 Hz), while the compound muscle

  14. Color pattern-reversal visual evoked potential in eyes with ocular hypertension and primary open-angle glaucoma

    Microsoft Academic Search

    Yi-Hao Shih; Zhu-Jing Huang; Ching-E Chang

    1991-01-01

    Color pattern-reversal visual evoked potential testing was performed in 99 normal eyes, 27 eyes with ocular hypertension and 30 eyes with primary open-angle glaucoma with the use of black-white, black-red and black-blue color checkerboard stimuli. The PI wave peak time and amplitude of the eyes with ocular hypertension and glaucoma were significantly different from those of age-similar normal eyes, especially

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

    NASA Astrophysics Data System (ADS)

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

    1998-09-01

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

  16. Early modulation of visual perception by emotional arousal: Evidence from steady-state visual evoked brain potentials

    Microsoft Academic Search

    Andreas Keil; Thomas Gruber; Matthias M. Müller; Stephan Moratti; Margarita Stolarova; Margaret M. Bradley; Peter J. Lang

    2003-01-01

    Allocation of processing resources to emotional picture stimuli was examined using steady-state visual evoked brain potentials\\u000a (ssVEPs). Participants viewed a set of 60 colored affective pictures from the International Affective Picture System, presented\\u000a in a flickering mode at 10 Hz in order to elicit ssVEPs. Phase and amplitude of the 10-Hz ssVEP were examined for six picture\\u000a categories: threat and

  17. The use of contact heat evoked potential stimulator (CHEPS) in magnetoencephalography for pain research

    PubMed Central

    Gopalakrishnan, Raghavan; Machado, Andre G.; Burgess, Richard C.; Mosher, John C.

    2013-01-01

    Background Contact heat evoked potentials (CHEP) is a thermal stimulus modality used in pain research. We examine a commercial CHEP stimulator (CHEPS) that is designed to work in an fMRI environment, but poorly understood in the MEG environment. The CHEPS attains target temperatures rapidly using sophisticated control signals that unfortunately induce artifacts in the MEG. In this paper, we summarize our experiences using the CHEPS in MEG to study pain using an experimental paradigm, and propose a novel method for managing its artifact. New method We introduce a novel damped sinusoid modeling (DSM) technique to remove the CHEPS artifact based on estimates of the underlying sinusoids and damping factors. We show comparisons to signal space projection (SSP) and temporal signal space separation (tSSS) methods. Results The CHEPS artifact is highly dynamic, yet deterministic, switching rapidly from one frequency to another, with different spatial components. The galvanic connection between the subject and the CHEPS probe alters its performance, making pre-characterization difficult. Comparison with existing methods SSP methods failed to remove the artifact completely. TSSS performed better than SSP; however, tSSS requires the use of a multipolar head model that decreases the dimensionality and possibly the information content of the data. In contrast, DSM offers a strictly temporal modeling approach in which the artifact is estimated as a sum of damped sinusoids which is subtracted from the data. Conclusion Though the CHEPS increases the noise floor and introduces artifacts to the data, we believe the device can be successfully used in MEG if appropriate artifact removal techniques are followed. PMID:23994044

  18. Difference of Diagnostic Rates and Analytical Methods in the Test Positions of Vestibular Evoked Myogenic Potentials

    PubMed Central

    Park, Jeong Mee; Yong, Sang Yeol; Kim, Jong Heon; Kim, Hee; Park, Sang-Yoo

    2014-01-01

    Objective To compare the differences of diagnostic rates, of the two widely used test positions, in measuring vestibular evoked myogenic potentials (VEMP) and selecting the most appropriate analytical method for diagnostic criteria for the patients with vertigo. Methods Thirty-two patients with vertigo were tested in two comparative testing positions: turning the head to the opposite side of the evaluating side and bowing while in seated position, and bowing while in supine positions. Abnormalities were determined by prolonged latency of p13 or n23, shortening of the interpeak latency, and absence of VEMP formation. Results Using the three criteria above for determining abnormalities, both the seated and supine positions showed no significant differences in diagnostic rates, however, the concordance correlation of the two positions was low. When using only the prolonged latency of p13 or n23 in the two positions, diagnostic rates were not significantly different and their concordance correlation was high. On the other hand, using only the shortened interpeak latency in both positions showed no significant difference of diagnostic rates, and the degree of agreement between two positions was low. Conclusion Bowing while in seated position with the head turned in the opposite direction to the area being evaluated is found to be the best VEMP test position due to the consistent level of sternocleidomastoid muscle tension and the high level of compliance. Also, among other diagnostic analysis methods, using prolonged latency of p13 or n23 as the criterion is found to be the most appropriate method of analysis for the VEMP test. PMID:24855617

  19. Compound gravity receptor polarization vectors evidenced by linear vestibular evoked potentials

    NASA Technical Reports Server (NTRS)

    Jones, S. M.; Jones, T. A.; Bell, P. L.; Taylor, M. J.

    2001-01-01

    The utricle and saccule are gravity receptor organs of the vestibular system. These receptors rely on a high-density otoconial membrane to detect linear acceleration and the position of the cranium relative to Earth's gravitational vector. The linear vestibular evoked potential (VsEP) has been shown to be an effective non-invasive functional test specifically for otoconial gravity receptors (Jones et al., 1999). Moreover, there is some evidence that the VsEP can be used to independently test utricular and saccular function (Taylor et al., 1997; Jones et al., 1998). Here we characterize compound macular polarization vectors for the utricle and saccule in hatchling chickens. Pulsed linear acceleration stimuli were presented in two axes, the dorsoventral (DV, +/- Z axis) to isolate the saccule, and the interaural (IA, +/- Y axis) to isolate the utricle. Traditional signal averaging was used to resolve responses recorded from the surface of the skull. Latency and amplitude of eighth nerve components of the linear VsEP were measured. Gravity receptor responses exhibited clear preferences for one stimulus direction in each axis. With respect to each utricular macula, lateral translation in the IA axis produced maximum ipsilateral response amplitudes with substantially greater amplitude intensity (AI) slopes than medially directed movement. Downward caudal motions in the DV axis produced substantially larger response amplitudes and AI slopes. The results show that the macula lagena does not contribute to the VsEP compound polarization vectors of the sacculus and utricle. The findings suggest further that preferred compound vectors for the utricle depend on the pars externa (i.e. lateral hair cell field) whereas for the saccule they depend on pars interna (i.e. superior hair cell fields). These data provide evidence that maculae saccule and utricle can be selectively evaluated using the linear VsEP.

  20. Clinical Utility and Limitations of Intraoperative Monitoring of Visual Evoked Potentials

    PubMed Central

    Luo, Yeda; Regli, Luca; Bozinov, Oliver; Sarnthein, Johannes

    2015-01-01

    Objectives During surgeries that put the visual pathway at risk of injury, continuous monitoring of the visual function is desirable. However, the intraoperative monitoring of the visual evoked potential (VEP) is not yet widely used. We evaluate here the clinical utility of intraoperative VEP monitoring. Methods We analyzed retrospectively 46 consecutive surgeries in 2011-2013. High luminance stimulating devices delivered flash stimuli on the closed eyelid during intravenous anesthesia. We monitored VEP features N75 and P100 and took patients' preoperative and postoperative visual function from patient charts. Postoperative ophthalmologic workup was performed in 25 (54%) patients and preoperatively in 28 (61%) patients. Results VEP recordings were feasible in 62 of 85 eyes (73%) in 46 patients. All 23 eyes without VEP had impaired vision. During surgery, VEPs remained stable throughout surgery in 50 eyes. In 44 of these, visual function did not deteriorate and three patients (6 eyes) developed hemianopia. VEP decreased transiently in 10 eyes and visual function of all was preserved. VEPs were lost permanently in 2 eyes in two patients without new postoperative visual impairment. Conclusions Satisfactory intraoperative VEP monitoring was feasible in all patients except in those with severe visual impairment. Preservation of VEPs predicted preserved visual function. During resection of lesions in the visual cortex, VEP monitoring could not detect new major visual field defects due to injury in the posterior visual pathway. Intraoperative VEPs were sensitive enough to detect vascular damage during aneurysm clipping and mechanical manipulation of the anterior visual pathway in an early reversible stage. Intraoperative VEP monitoring influenced surgical decisions in selected patients and proved to be a useful supplement to the toolbox of intraoperative neurophysiological monitoring. PMID:25803287

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

    NASA Astrophysics Data System (ADS)

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

    2008-03-01

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

  2. Alterations in flash evoked potentials (FEPs) in rats produced by 3,3'-iminodipropionitrile (IDPN).

    PubMed

    Herr, D W; King, D; Barone, S; Crofton, K M

    1995-01-01

    3,3'-Iminodipropionitrile (IDPN) is a neurotoxicant that produces changes in flash evoked potentials (FEPs) 18 weeks after treatment. We examined dose- and time-related effects of IDPN on FEPs at earlier time points than previously studied (52). Adult male Long-Evans rats were given IDPN (0, 100, 200, 400 mg/kg/day x 3 days, i.p.) and FEPs were recorded 14 days later. IDPN (400 mg/kg/day) decreased the amplitudes of some of the "early" and "middle" FEP peaks (n30 and N56), and increased the latencies of some early peaks (P21 and P46). A separate group of rats was treated with IDPN (0 or 400 mg/kg/day x 3 days, i.p.) and FEPs were recorded 1, 3, 7, 14, and 35 days later. The latencies of of all portions of FEPs were increased by IDPN, with maximal changes occurring at 7 and/or 14 days. The amplitude of the middle portions of FEPs (peaks N56, P63, N70, P90) were altered as early as day 3, and some changes were observed up to day 14. In contrast, the "late" portion of FEPs (peak N160) was affected at later times (days 14 and 35). Corneal opacities were noted on days 3 and 7, but were largely reversible by day 14. In the time-course study, IDPN decreased colonic temperature on days 1, 3, 7, and 14. The present results suggest that IDPN alters both the early FEP peaks related to the initial afferent sensory volley, and cortical processing associated with the middle and later portions of FEPs. PMID:8747746

  3. Methylphenidate alters flash-evoked potentials, body temperature, and behavior in Long-Evans rats.

    PubMed

    Hetzler, Bruce E; Meckel, Katherine R; Stickle, Bruce A

    2014-01-01

    This experiment examined the effects of methylphenidate hydrochloride on flash-evoked potentials (FEPs) recorded from the visual cortex (VC) and superior colliculus (SC) of chronically implanted male Long-Evans rats, as well as on body temperature and open field behavior. FEPs were recorded at 10, 20 and 40 min following intraperitoneal injections of saline, and of doses of 0.7, 2.9, and 11.6 mg/kg methylphenidate on separate days. The 0.7 mg/kg dose did not produce significant effects. In the VC, following administration of the 11.6 mg/kg dose of methylphenidate the amplitude of components P83, N146, and P232 decreased, the amplitude of component N64 briefly increased and components P23, N30, N40, and P48 were unchanged in amplitude. In the SC, component P29 was unaffected, while components P38 and N51 were reduced in amplitude by the 11.6 mg/kg dose of methylphenidate. Peak latencies of components N40, P48, P83, and N146 in the VC and component P38 in the SC were increased by the 11.6 mg/kg dose of methylphenidate. When body temperature was recorded 45 min after drug administration, a mild dose-dependent hypothermia was found with the 2.9 and 11.6 mg/kg methylphenidate doses, suggesting that this may have contributed to the increased latencies. In subsequent open field observations, both line crossings and rearings were significantly increased by the 11.6 mg/kg dose. Increased movement into the center of the testing area was also observed, which could be a sign of increased exploration and reduced anxiety following methylphenidate. PMID:24269544

  4. Visual evoked potentials in phenylketonuria: association with brain MRI, dietary state, and IQ.

    PubMed

    Jones, S J; Turano, G; Kriss, A; Shawkat, F; Kendall, B; Thompson, A J

    1995-09-01

    At separate institutions, pattern reversal visual evoked potentials (VEPs) were recorded in children and older patients with phenylketonuria and compared with MRI of the brain. In nine patients aged less than 14 years, who were still on a diet low in phenylalanine, VEPs were clearly abnormal in only one and the abnormalities seen on MRI were mild. In 27 patients aged 14-31 years VEPs were abnormal in more than 80%, with significant reduction of amplitude and prolongation of latency despite the general absence of visual symptoms and abnormalities on routine neuro-ophthalmological examination. Among the older patients there was no significant correlation between VEP measures and plasma phenylalanine or tyrosine concentrations; neither was the incidence of VEP abnormalities dependent on whether or not the patients were still on a low phenylalanine diet. Some VEP amplitude measures were inversely correlated with the MRI lesion score, perhaps reflecting the severity of white matter abnormalities in the parieto-occipital region. In the older patients the amplitude of VEPs to stimulation of the central 8 degrees of the visual field was significantly correlated with IQ. The study confirms the high incidence of subclinical visual pathway involvement in older children and adults with phenylketonuria, and suggests the possibility of a link between the abnormal appearance of subcortical white matter on MRI and a physiological index of function of the CNS. As there was no evidence of general intellectual decline, it is suggested that the correlation between central field VEP amplitude and IQ may reflect abnormal development during infancy. Abnormalities on MRI, on the other hand, seem to be more closely related to current dietary state and phenylalanine concentration. PMID:7673953

  5. Visual evoked potentials in relation to factors of imprisonment in detention camps.

    PubMed

    Vrca, A; Bozikov, V; Brzovi?, Z; Fuchs, R; Malinar, M

    1996-01-01

    Visual evoked potentials (VEPs) of the pattern shift reversal type were determined in a representative group of 57 prisoners of war (POWs) released in 1992 from detention camps in former Yugoslavia. The parameters were correlated with the conditions in four camps (1-4). All subjects were male, with a mean age of 34.75 years (SD +/- 8.92), average length of imprisonment 192.7 days (SD +/- 77.6), mean loss of body mass during imprisonment 19.32% (SD +/- 9.54), and the average number of reported blows to the head and neck was 25.7 (SD +/- 20.3). VEPs were determined on average 290.5 days after the last craniocerebral trauma caused by blows to the head and neck (SD +/- 152.0) i.e., on average 218.5 days after release from the camp (SD +/- 164.3). Although all the 57 POWs reported being maltreated to a certain extent, 14 reported being subjected to particularly brutal forms of torture, 5 had been held in solitary confinement and 25 had lost consciousness at least once. Solitary confinement and loss of consciousness had the most significant effect on VEPs, and the altered VEP parameters correlated significantly with the craniocerebral trauma experienced, loss of body mass and the length of time since the last craniocerebral trauma until examination, and from release until examination. However, the length of imprisonment and treatment in the camps did not have a significant effect on VEP parameters. The study confirmed that under such conditions the age of the subject is a risk factor. The results of this study also confirmed that prisoners in one camp had been subjected to the worst maltreatment. PMID:8956983

  6. Effect of sevoflurane concentration on visual evoked potentials with pattern stimulation in dogs.

    PubMed

    Ito, Yosuke; Maehara, Seiya; Itoh, Yoshiki; Hayashi, Miri; Kubo, Akira; Itami, Takaharu; Ishizuka, Tomohito; Tamura, Jun; Yamashita, Kazuto

    2015-03-01

    The purpose of this study was to investigate the effects of sevoflurane concentration on canine visual evoked potentials with pattern stimulation (P-VEPs). Six clinically normal laboratory-beagle dogs were used. The minimum alveolar concentration (MAC) of sevoflurane was detected from all subjects by tail clamp method. The refractive power of the right eyes of all subjects was corrected to -2 diopters after skiascopy. For P-VEP recording, the recording and reference electrode were positioned at inion and nasion, respectively, and the earth electrode was positioned on the inner surface. To grasp the state of CNS suppression objectively, the bispectral index (BIS) value was used. The stimulus pattern size and distance for VEP recording were constant, 50.3 arc-min and 50 cm, respectively. P-VEPs and BIS values were recorded under sevoflurane in oxygen inhalational anesthesia at 0.5, 1.0, 1.5, 2.0, 2.5 and 2.75 sevoflurane MAC. For analysis of P-VEP, the P100 implicit time and N75-P100 amplitude were estimated. P-VEPs were detected at 0.5 to 1.5 MAC in all dogs, and disappeared at 2.0 MAC in four dogs and at 2.5 and 2.75 MAC in one dog each. The BIS value decreased with increasing sevoflurane MAC, and burst suppression began to appear from 1.5 MAC. There was no significant change in P100 implicit time and N75-P100 amplitude with any concentration of sevoflurane. At concentrations around 1.5 MAC, which are used routinely to immobilize dogs, sevoflurane showed no effect on P-VEP. PMID:25373729

  7. Effect of sevoflurane concentration on visual evoked potentials with pattern stimulation in dogs

    PubMed Central

    ITO, Yosuke; MAEHARA, Seiya; ITOH, Yoshiki; HAYASHI, Miri; KUBO, Akira; ITAMI, Takaharu; ISHIZUKA, Tomohito; TAMURA, Jun; YAMASHITA, Kazuto

    2014-01-01

    The purpose of this study was to investigate the effects of sevoflurane concentration on canine visual evoked potentials with pattern stimulation (P-VEPs). Six clinically normal laboratory-beagle dogs were used. The minimum alveolar concentration (MAC) of sevoflurane was detected from all subjects by tail clamp method. The refractive power of the right eyes of all subjects was corrected to ?2 diopters after skiascopy. For P-VEP recording, the recording and reference electrode were positioned at inion and nasion, respectively, and the earth electrode was positioned on the inner surface. To grasp the state of CNS suppression objectively, the bispectral index (BIS) value was used. The stimulus pattern size and distance for VEP recording were constant, 50.3 arc-min and 50 cm, respectively. P-VEPs and BIS values were recorded under sevoflurane in oxygen inhalational anesthesia at 0.5, 1.0, 1.5, 2.0, 2.5 and 2.75 sevoflurane MAC. For analysis of P-VEP, the P100 implicit time and N75-P100 amplitude were estimated. P-VEPs were detected at 0.5 to 1.5 MAC in all dogs, and disappeared at 2.0 MAC in four dogs and at 2.5 and 2.75 MAC in one dog each. The BIS value decreased with increasing sevoflurane MAC, and burst suppression began to appear from 1.5 MAC. There was no significant change in P100 implicit time and N75-P100 amplitude with any concentration of sevoflurane. At concentrations around 1.5 MAC, which are used routinely to immobilize dogs, sevoflurane showed no effect on P-VEP. PMID:25373729

  8. Case of acute zonal occult outer retinopathy with abnormal pattern visual evoked potentials.

    PubMed

    Chai, Yuzhu; Yamazaki, Hiroko; Fujinami, Kaoru; Tsunoda, Kazushige; Yamamoto, Shuichi

    2011-01-01

    Electrophysiological and morphological findings were studied in a case of acute zonal occult outer retinopathy (AZOOR) showing abnormal pattern visual evoked potentials (VEPs) at the onset and significant functional recovery in the natural course. A 21-year-old woman presented with acute onset of photopsia and a large scotoma in the right eye of 2 weeks duration. Her visual acuity was 20/20 in both eyes with no ophthalmoscopic and fluorescein angiographic abnormalities. However, a relative afferent pupillary defect and an enlarged blind spot were found in the right eye. The pattern VEPs were severely reduced when the right eye was stimulated. The amplitudes of both rod and cone full-field electroretinographics (ERGs) were reduced in the right eye. The amplitudes of the multifocal ERGs were reduced in the area of the enlarged blind spot. Irregularities in the inner segment/outer segment (IS/OS) line of the photoreceptors were observed over the nasal fovea by optical coherence tomography (OCT). The patient was followed without treatment. The enlarged blind spot disappeared in 3 months after the onset. At 5 months, reappearance of the IS/OS line was detected by OCT. At 6 months, the P(100) recovered to normal values. At 1 year, the reduced full-field ERGs were almost normal size and the multifocal ERGs in the area corresponding to the enlarged blind spot were also improved. ERG findings are crucial for differentiating AZOOR from retrobulbar neuritis, especially in patients with abnormal pattern VEPs. The pattern VEPs, full-field ERGs, multifocal ERGs, and OCT images can be abnormal in the early phase of AZOOR, but they can all improve during the natural course. PMID:21966193

  9. [Effects of isoflurane and halothane on motor evoked potentials in the rabbit].

    PubMed

    Terrier, G; Lansade, A; Preux, P M; Tabaraud, F; Moulies, D

    1993-01-01

    The effects of isoflurane or halothane on motor evoked potentials (MEPs) were assessed and compared in the rabbit, in order to contribute to devise a rigorous human anaesthetic protocol to be used for monitoring of MEPs in corrective spinal surgery. Ten black adult New Zealand rabbits were anaesthetised twice at a month interval, once with isoflurane and once with halothane. Once a control cortical stimulation had been carried out after the animal had breathed pure oxygen for three minutes, the following concentrations of anaesthetic agent were given for 3 min each: respectively 0.3 vol %, 0.5 vol % and 1 vol % of isoflurane, and 0.5 vol % and 1 vol % of halothane. Cortical stimulation was carried out every minute. The signs of anaesthesia (diameter decrease of the pupil, eye covered by the nictating membrane), muscle relaxation (ears drop) and breathing rate were recorded. MEPs were recorded 1, 2, 3 and 5 minutes after the end of anaesthesia. Isoflurane had a stronger effect on MEPs than halothane. The effect was more pronounced on amplitude than on latency. MEPs remained present whatever the concentration of halothane. In 70% of cases, MEPs, discontinued with isoflurane, more rapidly, more deeply, and for a longer time. Mean latency was more constantly increased in the isoflurane than in the halothane group. The effect of volatile halogenated anaesthetics on mean latency of MEPs seemed to be more delayed than that on amplitude. One should also take into account an individual sensitivity, it is concluded that the interpretation of MEPs during anaesthesia with volatile halogenated agents should be carried out with caution. PMID:8250367

  10. Single Trial Visual Evoked Potential Extraction using Partial Least Squares-based Approach.

    PubMed

    Hutapea, Duma Kristina; Yusoff, Mohd Zuki; Asirvadam, Vijanth Sagayan

    2014-11-01

    A single trial extraction of a Visual Evoked Potential (VEP) signal based on the Partial Least Squares (PLS) regression method has been proposed in this paper. This paper has focused on the extraction and estimation of the latencies of P100, P200, P300, N75 and N135 in the artificial Electroencephalograph (EEG) signal. The real EEG signal obtained from the hospital was only concentrated on the P100. The performance of the PLS has been evaluated mainly on the basis of latency error rate of the peaks for the artificial EEG signal, and the mean peak detection and standard deviation for the real EEG signal. The simulation results show that the proposed PLS algorithm is capable of reconstructing the EEG signal into its desired shape of the ideal VEP. For P100, the proposed PLS algorithm is able to provide comparable results to the Generalized Eigenvalue Decomposition (GEVD) algorithm which alters (pre-whitens) the EEG input signal using the pre-stimulation EEG signal. It has also shown better performance for later peaks (P200 and P300). The PLS outperformed not only in positive peaks but also in N75. In P100 the PLS was comparable with the GEVD although N135 was better estimated by GEVD. The proposed PLS algorithm is comparable to GEVD given that PLS does not alter the EEG input signal. The PLS algorithm gives the best estimate to multi-trial ensemble averaging. This research offers benefits such as avoiding patient's fatigue during VEP test measurement in hospital, in BCI applications and in EEG-fMRI integration. PMID:25376049

  11. Lack of cold pressor test-induced effect on visual-evoked potentials in migraine.

    PubMed

    Coppola, Gianluca; Currà, Antonio; Serrao, Mariano; Di Lorenzo, Cherubino; Gorini, Manuela; Porretta, Elisa; Alibardi, Alessia; Parisi, Vincenzo; Pierelli, Francesco

    2010-04-01

    In patients with migraine, the various sensory stimulation modalities, including visual stimuli, invariably fail to elicit the normal response habituation. Whether this lack of habituation depends on abnormal activity in the sub-cortical structures responsible for processing incoming information as well as nociception and antinociception or on abnormal cortical excitability per se remains debateable. To find out whether inducing tonic pain in the hand by cold pressure test (CPT) alters the lack of visual-evoked potential (VEP) habituation in migraineurs without aura studied between attacks we recorded VEPs in 19 healthy subjects and in 12 migraine patients during four experimental conditions: baseline; no-pain (hand held in warm water, 25 degrees C); pain (hand held in cold water, 2-4 degrees C); and after-effects. We measured P100 amplitudes from six blocks of 100 sweeps, and assessed habituation from amplitude changes between the six sequential blocks. In healthy subjects, the CPT decreased block 1 VEP amplitude and abolished the normal VEP habituation (amplitude decrease to repeated stimulation) in patients with migraine studied between attacks; it left block 1 VEP amplitude and abnormal VEP habituation unchanged. These findings suggest that the interictal cortical dysfunction induced by migraine prevents the cortical changes induced by tonic painful stimulation both during pain and after pain ends. Because such cortical changes presumably reflect plasticity mechanisms in the stimulated cortex, our study suggests altered plasticity of sensory cortices in migraine. Whether this abnormality reflects abnormal functional activity in the subcortical structures subserving tonic pain activation remains conjectural. PMID:20012123

  12. 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.

  13. Diagnostic validity of somatosensory evoked potentials in subgroups of patients with sciatica.

    PubMed

    Pape, E; Eldevik, P; Vandvik, B

    2002-02-01

    The diagnostic utility of scalp-recorded somatosensory evoked potentials (SEP) in patients with sciatica has generally been regarded as low. The purpose of the present study was to determine the validity of sensory nerve SEP in different subgroups of sciatic patients. A total of 65 consecutive patients with sciatica showing disc pathology and/or facet joint hypertrophy on lumbar computed tomography (CT) and/or myelography were studied. Symptomatic myelographically compressed nerve roots were defined as truly compromised roots. Asymptomatic myelographically normal nerve roots were defined as truly normal roots. Bilateral sensory nerve SEP representing nerve roots L4, L5, and S1 were performed in all patients. Evaluation of SEP included the use of P1 latency inter-root comparison. The false-positive rate of SEP was low. Pathological L4, L5, and S1 SEP therefore strongly indicate true compromise of the corresponding nerve roots. The true-positive rate was higher in patients with facet joint hypertrophy with or without additional disc disease than in patients with disc pathology only, and highest if the sciatic sensory symptoms were present during the SEP registration. Diagnostic validity was not influenced by previous episodes of sciatica, the duration of the present episode, or the number of spinal levels with ipsilateral myelographically compressed nerve roots. Pathological SEP strongly indicate sensory radiculopathy in patients with sciatica. Diagnostic efficacy is higher in patients with facet joint hypertrophy than in patients with disc pathology only and highest when the sciatic symptoms are present during registration. PMID:11931062

  14. Differences in early sensory-perceptual processing in synesthesia: a visual evoked potential study.

    PubMed

    Barnett, Kylie J; Foxe, John J; Molholm, Sophie; Kelly, Simon P; Shalgi, Shani; Mitchell, Kevin J; Newell, Fiona N

    2008-11-15

    Synesthesia is a condition where stimulation of a single sensory modality or processing stream elicits an idiosyncratic, yet reliable perception in one or more other modalities or streams. Various models have been proposed to explain synesthesia, which have in common aberrant cross-activation of one cortical area by another. This has been observed directly in cases of linguistic-color synesthesia as cross-activation of the 'color area', V4, by stimulation of the grapheme area. The underlying neural substrates that mediate cross-activations in synesthesia are not well understood, however. In addition, the overall integrity of the visual system has never been assessed and it is not known whether wider differences in sensory-perceptual processing are associated with the condition. To assess whether fundamental differences in perceptual processing exist in synesthesia, we utilised high-density 128-channel electroencephalography (EEG) to measure sensory-perceptual processing using stimuli that differentially bias activation of the magnocellular and parvocellular pathways of the visual system. High and low spatial frequency gratings and luminance-contrast squares were presented to 15 synesthetes and 15 controls. We report, for the first time, early sensory-perceptual differences in synesthetes relative to non-synesthete controls in response to simple stimuli that do not elicit synesthetic color experiences. The differences are manifested in the early sensory components of the visual evoked potential (VEP) to stimuli that bias both magnocellular and parvocellular responses, but are opposite in direction, suggesting a differential effect on these two pathways. We discuss our results with reference to widespread connectivity differences as a broader phenotype of synesthesia. PMID:18723094

  15. Effects of isoflurane on somatosensory-evoked potentials in calves: A pilot study.

    PubMed

    Truchetti, Geoffrey; Burns, Patrick; Nichols, Sylvain; Parent, Joane

    2015-01-01

    Somatosensory evoked potentials (SSEP) are used to monitor sensory function and are often recorded under general anesthesia. The objective of the study was to evaluate the effects of isoflurane on SSEPs in calves as it has not been reported. Eight calves (mean age: 40 days), were included in the study. Calves were anesthetized with a randomized sequence of four different isoflurane partial pressures. Blood gas analysis was performed before each measurement. SSEP were induced by repeated stimulation of the common dorsal digital nerve III. SSEPs were recorded from the lumbo-sacral junction (s-SSEP) and the head (c-SSEP). Latency and inter-amplitude of each peak were measured. For s-SSEP: One negative (Nsp1) and two positive (Psp1 and Psp2) peaks were identified in all tracings except for two calves. There was a significant effect of isoflurane on the latency of Psp2 (P = 0.01). Inter-amplitude decreased significantly with PaO2, PaCO2 and temperature (P < 0.05). Psp2 latency decreased with PaO2 (P = 0.01). For c-SSEP: two positive (Pc1 and Pc2) and two negative (Nc1 and Nc2) peaks were identified. There were identifiable peaks for the analysis of Pc1 latencies only. There was a significant positive linear relation between end-tidal isoflurane partial pressure (ETiso) and Pc1 latency (P = 0.04). None of the co-variables had a significant effect on the latency of Pc1 (P > 0.1). Isoflurane has a major impact on the recording of c-SSEP. Recording should be done at the lowest ETiso as possible, and anesthesia parameters should be kept constant. PMID:25673905

  16. Impedance and Electrically Evoked Compound Action Potential (ECAP) Drop within 24 Hours after Cochlear Implantation

    PubMed Central

    Chen, Joshua Kuang-Chao; Chuang, Ann Yi-Chiun; Sprinzl, Georg Mathias; Tung, Tao-Hsin; Li, Lieber Po-Hung

    2013-01-01

    Previous animal study revealed that post-implantation electrical detection levels significantly declined within days. The impact of cochlear implant (CI) insertion on human auditory pathway in terms of impedance and electrically evoked compound action potential (ECAP) variation within hours after surgery remains unclear, since at this time frequency mapping can only commence weeks after implantation due to factors associated with wound conditions. The study presented our experiences with regards to initial switch-on within 24 hours, and thus the findings about the milieus inside cochlea within the first few hours after cochlear implantation in terms of impedance/ECAP fluctuations. The charts of fifty-four subjects with profound hearing impairment were studied. A minimal invasive approach was used for cochlear implantation, characterized by a small skin incision (?2.5 cm) and soft techniques for cochleostomy. Impedance/ECAP was measured intro-operatively and within 24 hours post-operatively. Initial mapping within 24 hours post-operatively was performed in all patients without major complications. Impedance/ECAP became significantly lower measured within 24 hours post-operatively as compared with intra-operatively (p<0.001). There were no differences between pre-operative and post-operative threshold for air-conduction hearing. A significant drop of impedance/ECAP in one day after cochlear implantation was revealed for the first time in human beings. Mechanisms could be related to the restoration of neuronal sensitivity to the electrical stimulation, and/or the interaction between the matrix enveloping the electrodes and the electrical stimulation of the initial switch-on. Less wound pain/swelling and soft techniques both contributed to the success of immediate initial mapping, which implied a stable micro-environment inside the cochlea despite electrodes insertion. Our research invites further studies to correlate initial impedance/ECAP changes with long-term hearing/speech performance. PMID:23991008

  17. Effects of symptomatic treatments on cutaneous hyperalgesia and laser evoked potentials during migraine attack.

    PubMed

    de Tommaso, M; Losito, L; Libro, G; Guido, M; Di Fruscolo, O; Sardaro, M; Sciruicchio, V; Lamberti, P; Livrea, P

    2005-05-01

    Previously an amplitude enhancement of laser evoked potentials (LEPs) was detected during migraine attack: we further examined pain threshold to CO2 laser stimuli and LEPs during attacks, evaluating the effect of almotriptan, lysine-acetylsalicylate and placebo treatment on cutaneous hyperalgesia to thermal stimuli delivered by CO2 laser and on LEP components. Eighteen patients suffering from migraine without aura were analysed. They were divided into three groups of six patients each, randomly assigned to lysine acetyl-salicylate, almotriptan or placebo treatments. The supraorbital zones and the dorsum of the hand were stimulated on both the symptomatic and not symptomatic side in all patients. The LEPs were recorded by 25 scalp electrodes. During attacks, the P2 wave was significantly enhanced; the amplitude of the P2 component obtained by the stimulation of the supraorbital zone during the attack on the side of the headache was significantly correlated with the intensity of pain and the frequency of headache. Both almotriptan and lysine acetyl-salicylate significantly reduced the P2 amplitude but they showed no effects on hyperalgesia to laser stimulation; headache relief following therapy was correlated with the reduction of the P2 amplitude. The cortical elaboration of laser-induced experimental pain seemed increased during migraine attack, and the severity of headache was mainly related to the increase of the later LEPs components expressing the attentive and emotive compounds of suffering. Reversion of this process appeared to be primarily responsible for the efficacy of drugs in treating migraine, though both almotriptan and lysine-acetil salicilate seemed to have no effect in reducing sensitization at second and third order nociceptive neurons. PMID:15839851

  18. Task related changes in contingent negative variation (CNV) response of endogenous evoked potentials.

    PubMed

    Sahai, V; Tandon, O P

    2000-07-01

    Contingent negative variation (CNV) is a slow negative cortical potential shift, which occurs during a warned foreperiod reaction time paradigm. Most studies of evoked potentials have concentrated on components occurring during the first 300 msec, although there are important and recordable aspects of signal processing occurring well beyond 300 msec e.g. late negative slow wave. CNV has proven sensitive to a number of psychological variables, none of which can yet be singled out as a definitive or exclusive correlate. Changes are expected if measured after a rigorous mental exercise. CNV was measured in 20 normal male subjects aged between 18 and 20 years. CNV was recorded twice in each subject before and after the administration of a mental task. The auditory mental task comprised repeating in reverse order string of random digits read out to the subject at a uniform speed of 1 per second. The visual mental task comprised reading laterally inverted type written text. Each subject had to undergo 2 sessions in separate sittings. The latency and amplitude of waves N1, P3, orientation (O), expectancy (E), CNV, reaction time (RT) were recorded. These values recorded before and after the task were compared statistically using student's unpaired t-test. The significant latencies recorded before and after the auditory task were, N1: 88.00 +/- 11.96 and 100.00 +/- 21.52 msec, P3: 289.00 +/- 54.85 and 299.00 +/- 52.91 msec, reaction time (RT): 102 +/- 17.05 msec and 123 +/- 17.5 msec, and in case of visual task, N1: 88 +/- 13.16 msec and 99.00 +/- 16.51 msec, reaction time (RT): 107 +/- 11.74 msec and 127 +/- 13.42 msec respectively. All other CNV wave latencies and amplitude changes were insignificant. Hence task effects sensory perception as reflected by increased latency of the long latency response N1 and the cortical integrative processes resulting in increased reaction time. PMID:10941619

  19. CHLORDIMEFORM PRODUCES PROFOUND, SELECTIVE, AND TRANSIENT CHANGES IN VISUAL EVOKED POTENTIALS OF HOODED RATS

    EPA Science Inventory

    Rat visual function was tested after acute exposure to chlordimeform (CDM), a formamidine insecticide/acaricide. Adult male Long-Evans rats were surgically implanted with epidural recording electrodes overlying visual cortex and tested 1 week later. Pattern reversal-evoked potent...

  20. Peripheral neuropathy and visual evoked potential changes in workers exposed to n-hexane

    Microsoft Academic Search

    Gulnihal Kutlu; Yasemin B. Gomceli; Tolga Sonmez; Levent E. Inan

    2009-01-01

    The aim of this study was to evaluate patients who had peripheral neuropathy and changes to their visual evoked responses resulting from exposure to n-hexane. Eighteen patients with acute or subacute neuropathy, who were working in a shoe factory, were investigated clinically and electrophysiologically. These evaluations were then repeated 9 months to 12 months after cessation of exposure to n-hexane.

  1. Fear Potentiation of Acoustic Startle Stimulus-Evoked Heart Rate Changes in Rats

    Microsoft Academic Search

    Brian J. Young; Robert N. Leaton

    1994-01-01

    The present study examined the extent to which heart rate changes evoked by acoustic startle stimuli are affected by the development of fear during startle testing. The phasic heart rate responses of rats elicited by a 120-dB startle stimulus were characterized by decelerations that habituated across trials and accelerations that developed across trials in a manner that paralleled the development

  2. Intraoperative motor evoked potential monitoring - a position statement by the American Society of Neurophysiological Monitoring.

    PubMed

    Macdonald, D B; Skinner, S; Shils, J; Yingling, C

    2013-12-01

    The following intraoperative MEP recommendations can be made on the basis of current evidence and expert opinion: (1) Acquisition and interpretation should be done by qualified personnel. (2) The methods are sufficiently safe using appropriate precautions. (3) MEPs are an established practice option for cortical and subcortical mapping and for monitoring during surgeries risking motor injury in the brain, brainstem, spinal cord or facial nerve. (4) Intravenous anesthesia usually consisting of propofol and opioid is optimal for muscle MEPs. (5) Interpretation should consider limitations and confounding factors. (6) D-wave warning criteria consider amplitude reduction having no confounding factor explanation: >50% for intramedullary spinal cord tumor surgery, and >30-40% for peri-Rolandic surgery. (7) Muscle MEP warning criteria are tailored to the type of surgery and based on deterioration clearly exceeding variability with no confounding factor explanation. Disappearance is always a major criterion. Marked amplitude reduction, acute threshold elevation or morphology simplification could be additional minor or moderate spinal cord monitoring criteria depending on the type of surgery and the program's technique and experience. Major criteria for supratentorial, brainstem or facial nerve monitoring include >50% amplitude reduction when warranted by sufficient preceding response stability. Future advances could modify these recommendations. PMID:24055297

  3. Block-Dependent Sedation during Epidural Anaesthesia is Associated with Delayed Brainstem Conduction

    PubMed Central

    Wadhwa, Anupama; Shah, Yunus M.; Lin, Chum-Ming; Haugh, Gilbert S.; Sessler, Daniel I.

    2005-01-01

    Neuraxial anaesthesia produces a sedative and anesthetic-sparing effect. Recent evidence suggests that spinal cord anaesthesia modifies reticulo-thalamo-cortical arousal by decreasing afferent sensory transmission. We hypothesized that epidural anaesthesia produces sensory deafferentation-dependent sedation that is associated with impairment of brainstem transmission. We used brainstem auditory evoked potentials (BAEP) to evaluate reticular function in 11 volunteers. Epidural anaesthesia was induced with 2% 2-chloroprocaine. Hemodynamic and respiratory responses, sensory block level, sedation depth and BAEP were assessed throughout induction and resolution of epidural anaesthesia. Sedation was evaluated using verbal rating score (VRS), observer's assessment alertness/sedation (OAA/S) score, and bispectral index (BIS). Prediction probability (PK) was used to associate sensory block with sedation, as well as BIS with other sedation measures. Spearman rank order correlation was used to associate block level and sedation with the absolute and interpeak BAEP latencies. Sensory block level significantly predicted VRS (PK = 0.747), OAA/S score (PK = 0.748) and BIS. Bispectral index predicted VRS and OAA/S score (PK = 0.728). The latency of wave III of BAEP significantly correlated with sedation level (rho = 0.335, P < 0.01) and sensory block (rho = 0.394, P < 0.01). The other BAEP parameters did not change during epidural anaesthesia. Hemodynamic and respiratory responses remained stable throughout the study. Sedation during epidural anaesthesia depends on sensory block level and is associated with detectable block-dependent alterations in the brainstem auditory evoked responses. Sensory deafferentation may reduce CNS alertness through mechanisms related to brainstem neural activity. PMID:15220178

  4. Modulation of amplitude and latency of motor evoked potential by direction of transcranial magnetic stimulation

    NASA Astrophysics Data System (ADS)

    Sato, Aya; Torii, Tetsuya; Iwahashi, Masakuni; Itoh, Yuji; Iramina, Keiji

    2014-05-01

    The present study analyzed the effects of monophasic magnetic stimulation to the motor cortex. The effects of magnetic stimulation were evaluated by analyzing the motor evoked potentials (MEPs). The amplitude and latency of MEPs on the abductor pollicis brevis muscle were used to evaluate the effects of repetitive magnetic stimulation. A figure eight-shaped flat coil was used to stimulate the region over the primary motor cortex. The intensity of magnetic stimulation was 120% of the resting motor threshold, and the frequency of magnetic stimulation was 0.1 Hz. In addition, the direction of the current in the brain was posterior-anterior (PA) or anterior-posterior (AP). The latency of MEP was compared with PA and AP on initial magnetic stimulation. The results demonstrated that a stimulus in the AP direction increased the latency of the MEP by approximately 2.5 ms. MEP amplitude was also compared with PA and AP during 60 magnetic stimulations. The results showed that a stimulus in the PA direction gradually increased the amplitude of the MEP. However, a stimulus in the AP direction did not modulate the MEP amplitude. The average MEP amplitude induced from every 10 magnetic pulses was normalized by the average amplitude of the first 10 stimuli. These results demonstrated that the normalized MEP amplitude increased up to approximately 150%. In terms of pyramidal neuron indirect waves (I waves), magnetic stimulation inducing current flowing backward to the anterior preferentially elicited an I1 wave, and current flowing forward to the posterior elicited an I3 wave. It has been reported that the latency of the I3 wave is approximately 2.5 ms longer than the I1 wave elicitation, so the resulting difference in latency may be caused by this phenomenon. It has also been reported that there is no alteration of MEP amplitude at a frequency of 0.1 Hz. However, this study suggested that the modulation of MEP amplitude depends on stimulation strength and stimulation direction.

  5. Nicotine-ethanol interactions in flash-evoked potentials and behavior of Long-Evans rats.

    PubMed

    Hetzler, Bruce E; Martin, Elizabeth I

    2006-01-01

    Although nicotine and ethanol are often used together, little is known about their combined effects on visual system electrophysiology. This experiment examined the separate and combined effects of nicotine and ethanol on flash-evoked potentials (FEPs) recorded from both the visual cortex (VC) and superior colliculus (SC) of chronically implanted male Long-Evans rats. There were four treatment conditions administered on separate days: either saline or ethanol (2.0 g/kg, i.p.) was given 10 min before either saline or nicotine (1.0 mg/kg, s.c.). FEPs were recorded at 5, 20, and 40 min following the second injection. In the VC, ethanol significantly decreased the amplitude of most components, but increased P46. Peaks P22 and N53 were unchanged. Nicotine enhanced most component amplitudes, but decreased N29 and P234, while P22 and N139 were unchanged. In the SC, ethanol depressed the amplitude of all components studied. In contrast, nicotine significantly depressed only P27 and N48. Latencies of most components in both structures were increased by ethanol, nicotine, and the combination treatment, although a nicotine-induced enhancement of the effects of ethanol on latencies was not typically observed. Each drug treatment also produced significant hypothermia, with the combination treatment resulting in the greatest hypothermia. Ethanol, either alone or in combination with nicotine, significantly reduced body movements during the FEP recording sessions. In subsequent open-field observations, ethanol, but not nicotine, significantly increased the number of squares crossed, while the combination treatment produced the greatest increase in movement. Nicotine significantly increased rearing behavior, but both ethanol and the combination treatment eliminated rearings. Overall, data suggesting that nicotine can counteract some of the effects of ethanol was demonstrated in varying degrees in the amplitude of VC components N39, P46, N53, N65, and P88, the latency of VC component N53, the amplitude of SC component N59, and the latency of SC components N48 and N54. In contrast, a nicotine-induced enhancement of the effects of ethanol was found for only the latency of VC components N39, P88, and P234, body temperature, and open-field ambulation. PMID:16430948

  6. Cortical evoked potentials of the vesicourethral junction – a predictor for the outcome of intravesical electrostimulation in patients with sensory and motor detrusor dysfunction

    Microsoft Academic Search

    G. Kiss; H. Madersbacher; W. Poewe

    1998-01-01

    The evaluation of cortical evoked potentials after stimulation of the vesicourethral junction shows accurate and reproducible\\u000a results and offers an elegant technique for evaluation of the viscerosensory pathways in patients with lower urinary tract\\u000a dysfunction. The results must be considered in context with the results of simultaneously investigated pudendal somatosensory\\u000a evoked potentials and the clinical symptomatology. They are of great

  7. Towards an optimization of stimulus parameters for brain-computer interfaces based on steady state visual evoked potentials.

    PubMed

    Duszyk, Anna; Bierzy?ska, Maria; Radzikowska, Zofia; Milanowski, Piotr; Ku?, Rafa?; Suffczy?ski, Piotr; Michalska, Magdalena; ?ab?cki, Maciej; Zwoli?ski, Piotr; Durka, Piotr

    2014-01-01

    Efforts to construct an effective brain-computer interface (BCI) system based on Steady State Visual Evoked Potentials (SSVEP) commonly focus on sophisticated mathematical methods for data analysis. The role of different stimulus features in evoking strong SSVEP is less often considered and the knowledge on the optimal stimulus properties is still fragmentary. The goal of this study was to provide insight into the influence of stimulus characteristics on the magnitude of SSVEP response. Five stimuli parameters were tested: size, distance, colour, shape, and presence of a fixation point in the middle of each flickering field. The stimuli were presented on four squares on LCD screen, with each square highlighted by LEDs flickering with different frequencies. Brighter colours and larger dimensions of flickering fields resulted in a significantly stronger SSVEP response. The distance between stimulation fields and the presence or absence of the fixation point had no significant effect on the response. Contrary to a popular belief, these results suggest that absence of the fixation point does not reduce the magnitude of SSVEP response. However, some parameters of the stimuli such as colour and the size of the flickering field play an important role in evoking SSVEP response, which indicates that stimuli rendering is an important factor in building effective SSVEP based BCI systems. PMID:25398134

  8. Towards an Optimization of Stimulus Parameters for Brain-Computer Interfaces Based on Steady State Visual Evoked Potentials

    PubMed Central

    Radzikowska, Zofia; Milanowski, Piotr; Ku?, Rafa?; Suffczy?ski, Piotr; Michalska, Magdalena; ?ab?cki, Maciej; Zwoli?ski, Piotr; Durka, Piotr

    2014-01-01

    Efforts to construct an effective brain-computer interface (BCI) system based on Steady State Visual Evoked Potentials (SSVEP) commonly focus on sophisticated mathematical methods for data analysis. The role of different stimulus features in evoking strong SSVEP is less often considered and the knowledge on the optimal stimulus properties is still fragmentary. The goal of this study was to provide insight into the influence of stimulus characteristics on the magnitude of SSVEP response. Five stimuli parameters were tested: size, distance, colour, shape, and presence of a fixation point in the middle of each flickering field. The stimuli were presented on four squares on LCD screen, with each square highlighted by LEDs flickering with different frequencies. Brighter colours and larger dimensions of flickering fields resulted in a significantly stronger SSVEP response. The distance between stimulation fields and the presence or absence of the fixation point had no significant effect on the response. Contrary to a popular belief, these results suggest that absence of the fixation point does not reduce the magnitude of SSVEP response. However, some parameters of the stimuli such as colour and the size of the flickering field play an important role in evoking SSVEP response, which indicates that stimuli rendering is an important factor in building effective SSVEP based BCI systems. PMID:25398134

  9. RADIATION ASSOCIATED BRAINSTEM INJURY

    PubMed Central

    Mayo, Charles; Yorke, Ellen; Merchant, Thomas E.

    2010-01-01

    Publications relating brainstem radiation toxicity to quantitative dose and dose–volume measures derived from three-dimensional treatment planning were reviewed. Despite the clinical importance of brainstem toxicity, most studies reporting brainstem effects after irradiation have fewer than 100 patients. There is limited evidence relating toxicity to small volumes receiving doses above 60–64 Gy using conventional fractionation and no definitive criteria regarding more subtle dose–volume effects or effects after hypofractionated treatment. On the basis of the available data, the entire brainstem may be treated to 54 Gy using conventional fractionation using photons with limited risk of severe or permanent neurological effects. Smaller volumes of the brainstem (1–10 mL) may be irradiated to maximum doses of 59 Gy for dose fractions ?2 Gy; however, the risk appears to increase markedly at doses >64 Gy. PMID:20171516

  10. Alterations in rat flash and pattern reversal evoked potentials after acute or repeated administration of carbon disulfide (CS2).

    PubMed

    Herr, D W; Boyes, W K; Dyer, R S

    1992-04-01

    Because solvents may selectively alter portions of visual evoked potentials, we examined the effects of carbon disulfide (CS2) on flash (FEPs) and pattern reversal (PREPs) evoked potentials. Long-Evans rats were administered ip carbon disulfide either acutely or for 30 days. FEPs or PREPs were recorded prior to and 1, 2, 4, 8, or 24 hr after a single dose of CS2 (0, 100, 200, 400, or 500 mg/kg). Flash evoked potentials were also recorded 1, 2, 6, and 24 hr after the last of 30 doses of 200 mg CS2/kg/day. Acute exposure to CS2 consistently decreased the amplitude of FEP peak N160 at 1 hr, depressed peak N30 amplitude over 2-4 hr, and increased the latency of peaks P21, N30, P46, N56, and N160 for up to 4 hr after treatment. Carbon disulfide decreased the amplitude of PREP peaks P65, N83, P88, and N122 4 hr after treatment. Colonic temperature was depressed up to 8 hr after treatment. Administration of 200 mg CS2/kg/day decreased the amplitude of FEP peak N30 and increased the latencies of peaks P21, N30, P46, N56, and N160 up to 24 hr after the last dose. The differential effects of CS2 on portions of FEPs indicate that FEP peaks can be independently modulated. Changes in PREPs were temporally correlated with alterations in early FEP peaks, but FEP peak N160 was depressed at an earlier time point. Repeated CS2 exposure affected FEPs at lower doses and for a longer time than an acute exposure, similar to the reported greater severity of neurological disturbances following repeated CS2 exposures in humans. PMID:1597259

  11. Acute effects of ethanol on pattern reversal and flash-evoked potentials in rats and the relationship to body temperature.

    PubMed

    Boyes, W K; Hetzler, B E; Dyer, R S

    1993-01-01

    The effects of acute ethanol treatment on flash and pattern reversal visual evoked potentials (FEPs and PREPs, respectively) were examined in three experiments using Long-Evans rats. The relationships of evoked potential parameters with blood ethanol concentration and body temperature were examined. In Experiment 1, rats were treated i.p. with vehicle or 0.5, 1.0 or 2.0 g ethanol/kg body weight, and tested 30 min later. The 2.0 g/kg group had prolonged latencies of PREP peaks, no changes in PREP peak-to-peak amplitudes, and lower body temperatures than saline-treated controls. The peak latency shifts were significantly correlated with both blood ethanol concentration and body temperature, and were of a magnitude to be expected from similar changes in body temperature alone. Experiment 2 measured both PREPs and paired-flash FEPs in rats 30 min after injection of either 0, 0.5 or 2.0 g/kg ethanol. PREP changes were found following treatment with the high dose which were similar to those of Experiment 1. Some FEP peak latencies were prolonged and peak-to-peak amplitudes were reduced by both doses of ethanol, despite the fact that body temperatures were reduced at only the high dose. At 2.0 g/kg ethanol, the FEP changes in latency, but not amplitude, were in accordance with what would be expected from body temperature changes alone. The third study attempted to investigate the role of reduced body temperature in producing the visual evoked potential changes by testing at room temperatures of 22 or 30 degrees C. Contrary to expectations, the rats receiving 2 g/kg ethanol were approx. 1 degree C cooler than controls at both room temperatures. Evoked potential latencies were greater in ethanol-treated rats than controls at both room temperatures. There were no significant effects of ethanol on FEP amplitudes. Overall, the effects of low doses of ethanol were independent of temperature changes, but the effects of higher doses of ethanol (2.0 g/kg) could not be distinguished from those produced by differences in body temperature alone. PMID:8432677

  12. Feasibility of intraoperative motor-evoked potential monitoring for skull base tumors with a high risk of postoperative motor deterioration

    Microsoft Academic Search

    Kimiaki Hashiguchi; Takato Morioka; Fumiaki Yoshida; Koji Yoshimoto; Tadahisa Shono; Yoshihiro Natori; Shinji Nagata; Tomio Sasaki

    2011-01-01

    Objective  To establish the validity and utility of motor-evoked potential (MEPs) monitoring for skull base tumor resection, we explored\\u000a the relationship between MEP monitoring results and postoperative motor function.\\u000a \\u000a \\u000a \\u000a \\u000a Methods  MEPs were successfully monitored during 76 operations in 68 patients with a high risk of motor morbidity. MEP monitoring data\\u000a were correlated with perioperative clinical motor function.\\u000a \\u000a \\u000a \\u000a \\u000a Results  MEPs remained stable in 56

  13. Assessment of intraoperative motor evoked potentials for predicting postoperative paraplegia in thoracic and thoracoabdominal aortic aneurysm repair

    Microsoft Academic Search

    Toshinori HoriuchiMasahiko; Masahiko Kawaguchi; Satoki Inoue; Hironobu Hayashi; Ryuichi Abe; Nobuoki Tabayashi; Shigeki Taniguchi; Hitoshi Furuya

    2011-01-01

    Purpose  Monitoring motor evoked potentials (MEPs) has been recognized as a highly reliable method to detect intraoperative spinal\\u000a cord ischemia (SCI) in aortic repair. However, the data regarding the sensitivity and specificity of MEPs for predicting postoperative\\u000a paraplegia are limited. We retrospectively assessed the value of intraoperative MEP amplitudes for predicting postoperative\\u000a paraplegia.\\u000a \\u000a \\u000a \\u000a \\u000a Methods  The medical records of 44 patients were reviewed.

  14. Pretreatment with physostigmine, mecamylamine and atropine reduces the impact of soman on the cortical visual evoked potential of the cat.

    PubMed

    DeBruyn, E J; Corbett, G K; Bonds, A B

    1991-01-01

    A pretreatment regimen of physostigmine, mecamylamine and atropine was evaluated for its ability to alleviate the impact of soman on visual system function as measured by changes in the cortical visual evoked potential (VEP) of the cat. Data from unprotected animals showed a threshold (30% depression in the VEP) of 6.4 micrograms/kg, while in pretreated animals, the threshold dose was 32.7 micrograms/kg, yielding a protection ratio of 5:1. Extending the time between pretreatment and exposure reduced the degree of protection. Pretreatment also reduced the degree of VEP depression at suprathreshold doses, indicating a therapeutic effect even in cases of severe exposure. PMID:2002756

  15. Determining electrically evoked compound action potential thresholds: A comparison of computer versus human analysis methods

    PubMed Central

    Glassman, E. Katelyn; Hughes, Michelle L.

    2012-01-01

    Objectives Current cochlear implants (CIs) have telemetry capabilities for measuring the electrically evoked compound action potential (ECAP). Neural Response Telemetry (NRT™; Cochlear) and Neural Response Imaging (NRI; Advanced Bionics [AB]) can measure ECAP responses across a range of stimulus levels to obtain an amplitude growth function. Software-specific algorithms automatically mark the leading negative peak, N1, and the following positive peak/plateau, P2, and apply linear regression to estimate ECAP threshold. Alternatively, clinicians may apply expert judgments to modify the peak markers placed by the software algorithms, and/or use visual detection to identify the lowest level yielding a measurable ECAP response. The goals of this study were to: (1) assess the variability between human and computer decisions for (a) marking N1 and P2, and (b) determination of linear regression threshold (LRT) and visual detection threshold (VDT); and (2) compare LRT and VDT methods within and across human and computer decision methods. Design ECAP amplitude growth functions were measured for three electrodes in each of 20 ears (10 Cochlear Nucleus® 24RE/CI512, and 10 AB CII/90K). LRT, defined as the current level yielding an ECAP with zero amplitude, was calculated for both computer- (C-LRT) and human-picked peaks (H-LRT). VDT, defined as the lowest level resulting in a measurable ECAP response, was also calculated for both computer- (C-VDT) and human-picked peaks (H-VDT). Because NRI assigns peak markers to all waveforms but does not include waveforms with amplitudes less than 20 ?V in its regression calculation, C-VDT for AB subjects was defined as the lowest current level yielding an amplitude ?20 ?V. Results Overall, there were significant correlations between human and computer decisions for peak-marker placement, LRT, and VDT for both manufacturers (r = 0.78 to 1.00, p < 0.001). For Cochlear devices, LRT and VDT correlated equally well for both computer- and human-picked peaks (r = 0.98 to 0.99, p < 0.001), which likely reflects the well-defined NRT algorithm and the lower noise floor in the 24RE and CI512 devices. For AB devices, correlations between LRT and VDT for both peak-picker methods were weaker than for Cochlear devices (r = 0.69 to 0.85, p < 0.001), which likely reflect the higher noise floor of the system. Disagreement between computer and human decisions regarding the presence of an ECAP response occurred for 5.0 % of traces for Cochlear devices and 2.1 % of traces for AB devices. Conclusions Results indicate that human and computer peak-picking methods can be used with similar accuracy for both Cochlear and AB devices. Either C-VDT or C-LRT can be used with equal confidence for Cochlear 24RE and CI512 recipients because both methods are strongly correlated with human decisions. However for AB devices, greater variability exists between different threshold determination methods. This finding should be considered in the context of using ECAP measures to assist with programming CIs. PMID:22885406

  16. Effects of Motion Sickness Severity on the Vestibular-Evoked Myogenic Potentials

    PubMed Central

    Fowler, Cynthia G.; Sweet, Amanda; Steffel, Emily

    2015-01-01

    Background Motion sickness is a common debilitating condition associated with both actual and perceived motion. Despite the commonality, little is known about the underlying physiological mechanisms. One theory proposes that motion sickness arises from a mismatch between reality and past experience in vertical motions. Physiological tests of the vestibular system, however, have been inconclusive regarding the underlying pathogenesis. Cervical vestibular-evoked myogenic potentials (cVEMPs) arise from the saccule, which responds to vertical motion. If vertical motion elicits motion sickness, the cVEMP should be affected. Purpose The purpose of this investigation was to determine if cVEMP characteristics differ among individuals with a range of motion sickness susceptibility from negligible to severe. The hypothesis was that individuals with high susceptibility would have larger cVEMP amplitudes and shorter cVEMP latencies relative to those who are resistant to motion sickness. Research Design The study had two parts. The first was quasi-experimental in which participants comprised three groups based on susceptibility to motion sickness (low, mild-moderate, high) as identified on the short version of the Motion Sickness Susceptibility Questionnaire (MSSQ-S). The second part of the study was correlational and evaluated the specific relationships between the degree of motion sickness susceptibility and characteristics of the VEMPs. Study Sample A total of 24 healthy young adults (ages 20–24 yr) were recruited from the university and the community without regard to motion sickness severity. Data Collection and Analysis Participants took the MSSQ-S, which quantifies susceptibility to motion sickness. The participants had a range of motion sickness susceptibility with MSSQ raw scores from 0.0–36.6, which correspond to percent susceptibility from 0.0–99.3%. VEMPs were elicited by 500 Hz tone-bursts monaurally in both ears at 120 dB pSPL. MSSQ-S percent scores were used to divide the participants into low, mild-moderate, and high susceptibility groups. A fixed general linear model with repeated-measures analysis of variance tested cVEMP characteristics for the susceptibility groups (between participants) and ears (within participants). A univariate analysis of variance tested the cVEMP interaural amplitudes across groups. The second analysis was a regression of the severity of motion sickness in percent on cVEMP characteristics. Significance was defined as p < 0.05. Results Participants in the high susceptibility group had significantly higher cVEMP amplitudes than those in the low susceptibility group. cVEMP amplitudes did not differ between ears, and latencies did not differ between the two groups or between ears. Regression analysis on MSSQ-S percent susceptibility by VEMP amplitudes revealed a best-fit cubic function in both ears, with r2 values of more than 42%. The interaural asymmetry ratio was negatively associated with motion sickness susceptibility (r2 = 0.389). Conclusions The current study is the first to report that greater susceptibility to motion sickness is associated with larger cVEMP amplitudes and lower interaural cVEMP asymmetries. Larger interaural asymmetries in cVEMPs did not promote motion sickness susceptibility. The cVEMP findings implicate the saccule and its neural pathways in the production of motion sickness and are consistent with the theory that vertical motions elicit motion sickness. Motion sickness susceptibility may contribute to the variability in normative cVEMP amplitudes. PMID:25405837

  17. Brainstem Neurons Survive the Identical Ischemic Stress That Kills Higher Neurons: Insight to the Persistent Vegetative State

    PubMed Central

    Brisson, C. Devin; Hsieh, Yi-Ting; Kim, Danielle; Jin, Albert Y.; Andrew, R. David

    2014-01-01

    Global ischemia caused by heart attack, pulmonary failure, near-drowning or traumatic brain injury often damages the higher brain but not the brainstem, leading to a ‘persistent vegetative state’ where the patient is awake but not aware. Approximately 30,000 U.S. patients are held captive in this condition but not a single research study has addressed how the lower brain is preferentially protected in these people. In the higher brain, ischemia elicits a profound anoxic depolarization (AD) causing neuronal dysfunction and vasoconstriction within minutes. Might brainstem nuclei generate less damaging AD and so be more resilient? Here we compared resistance to acute injury induced from simulated ischemia by ‘higher’ hippocampal and striatal neurons versus brainstem neurons in live slices from rat and mouse. Light transmittance (LT) imaging in response to 10 minutes of oxygen/glucose deprivation (OGD) revealed immediate and acutely damaging AD propagating through gray matter of neocortex, hippocampus, striatum, thalamus and cerebellar cortex. In adjacent brainstem nuclei, OGD-evoked AD caused little tissue injury. Whole-cell patch recordings from hippocampal and striatal neurons under OGD revealed sudden membrane potential loss that did not recover. In contrast brainstem neurons from locus ceruleus and mesencephalic nucleus as well as from sensory and motor nuclei only slowly depolarized and then repolarized post-OGD. Two-photon microscopy confirmed non-recoverable swelling and dendritic beading of hippocampal neurons during OGD, while mesencephalic neurons in midbrain appeared uninjured. All of the above responses were mimicked by bath exposure to 100 µM ouabain which inhibits the Na+/K+ pump or to 1–10 nM palytoxin which converts the pump into an open cationic channel. Therefore during ischemia the Na+/K+ pump of higher neurons fails quickly and extensively compared to naturally resilient hypothalamic and brainstem neurons. The selective survival of lower brain regions that maintain vital functions will support the persistent vegetative state. PMID:24802253

  18. Assessment of Brainstem Function with Auricular Branch of Vagus Nerve Stimulation in Parkinson’s Disease

    PubMed Central

    Weise, David; Adamidis, Melanie; Pizzolato, Fabio; Rumpf, Jost-Julian; Fricke, Christopher; Classen, Joseph

    2015-01-01

    Background The efferent dorsal motor nucleus of the vagal nuclei complex may degenerate early in the course of Parkinson’s disease (PD), while efferent nucleus ambiguous, the principal source of parasympathetic vagal neurons innervating the heart, and afferent somatosensory nuclei remain intact. Objective To obtain neurophysiological evidence related to this pattern, we tested processing of afferent sensory information transmitted via the auricular branch of the vagus nerve (ABVN) which is known to be connected to autonomic regulation of cardiac rhythm. Methods In this cross-sectional observational study, we recorded (i) somatosensory evoked potentials (ABVN-SEP) and (ii) cutaneo-cardioautonomic response elicited by stimulation of the ABVN (modulation of heart-rate variability (HRV index; low frequency power, ln(LF), high frequency power, ln(HF); ln(LF/HF) ratio)) in 50 PD patients and 50 age and sex matched healthy controls. Additionally, auditory evoked potentials and trigeminal nerve SEP were assessed. Results Neither ABVN-SEP nor any of the other functional brainstem parameters differed between patients and controls. Although HRV index was decreased in PD patients, modulation of ln(LF/HF) by ABVN-stimulation, likely indicating cardiac parasympathetic activation, did not differ between both groups. Conclusions Findings do not point to prominent dysfunction of processing afferent information from ABVN and its connected parasympathetic cardiac pathway in PD. They are consistent with the known pattern of degeneration of the vagal nuclei complex of the brainstem. PMID:25849807

  19. Simultaneous Detection of P300 and Steady-State Visually Evoked Potentials for Hybrid Brain-Computer Interface

    PubMed Central

    Combaz, Adrien; Van Hulle, Marc M.

    2015-01-01

    Objective We study the feasibility of a hybrid Brain-Computer Interface (BCI) combining simultaneous visual oddball and Steady-State Visually Evoked Potential (SSVEP) paradigms, where both types of stimuli are superimposed on a computer screen. Potentially, such a combination could result in a system being able to operate faster than a purely P300-based BCI and encode more targets than a purely SSVEP-based BCI. Approach We analyse the interactions between the brain responses of the two paradigms, and assess the possibility to detect simultaneously the brain activity evoked by both paradigms, in a series of 3 experiments where EEG data are analysed offline. Main Results Despite differences in the shape of the P300 response between pure oddball and hybrid condition, we observe that the classification accuracy of this P300 response is not affected by the SSVEP stimulation. We do not observe either any effect of the oddball stimulation on the power of the SSVEP response in the frequency of stimulation. Finally results from the last experiment show the possibility of detecting both types of brain responses simultaneously and suggest not only the feasibility of such hybrid BCI but also a gain over pure oddball- and pure SSVEP-based BCIs in terms of communication rate. PMID:25815815

  20. Clinical Use of Skull Tap Vestibular Evoked Myogenic Potentials for the Diagnoses of the Cerebellopontine Angle Tumor Patients

    PubMed Central

    Yavuz, Erdem; Lachowska, Magdalena; Piercha?a, Katarzyna; Morawski, Krzysztof; Niemczyk, Kazimierz; Delgado, Rafael E.

    2014-01-01

    Objective. To document our experiences using a new skull tapping induced Vestibular Evoked Myogenic Potentials (tap VEMPs) technique combined with standard Auditory Vestibular Evoked Myogenic Potentials (AC VEMPs) for advanced clinical assessment of cerebellopontine angle tumor (CPAT) patients. Design and Study Sample. Three patients were selected in order to highlight observations shown in a larger patient population and to show the variability of the findings. Both tap VEMPs and AC VEMPs were acquired from the sternocleidomastoid muscle (SCM) with EMG-based biofeedback and monitoring. Results. The usefulness of VEMPs was demonstrated, indicating the presence of a tumor and contributing additional information as to the involved nerve bundles in two out of the three cases. Conclusion. Due to the sensory organ dependency and related innervations differences, acquiring both AC VEMPs and tap VEMPs is likely to increase the probability of diagnosing CPATs and provide more information on the involved vestibular nerve bundles. This study demonstrates the feasibility of the possible expansion and combination of tap VEMPs and AC VEMPs techniques into a clinical diagnostic battery for advanced assessment of CPAT patients and its contribution as a guideline for the use of tap VEMPs in general. PMID:24804198

  1. Captured by the pain: Pain steady-state evoked potentials are not modulated by selective spatial attention.

    PubMed

    Blöchl, Maria; Franz, Marcel; Miltner, Wolfgang H R; Weiss, Thomas

    2015-04-01

    Attention has been shown to affect the neural processing of pain. However, the exact mechanisms underlying this modulation remain unknown. Here, we used a new method called pain steady-state evoked potentials (PSSEPs) to investigate whether selective spatial attention affects EEG responses to tonic painful stimuli. In general, steady-state evoked potentials reflect changes in the EEG spectrum at a certain frequency that correspond to the frequency of a train of applied stimuli. In this study, high intensity transcutaneous electrical stimulation was delivered to both hands simultaneously with 31Hz and 37Hz, respectively. Subject?s attention was directed to one of the two trains of stimulation in order to detect a small gap that was occasionally interspersed into the stimulus trains. Thereby, they had to ignore the stimulation applied to the other hand. Results show that PSSEPs were induced at 31Hz and 37Hz at frontal and central electrodes. PSSEPs occurred contralaterally to the respective hand stimulated with that frequency. Surprisingly, the magnitude of PSSEPs was not modulated by spatial attention towards one of the two stimuli. Our results indicate that attention can hardly be shifted between two simultaneously applied tonic painful stimulations. PMID:25637852

  2. Action Potential-Evoked Calcium Release Is Impaired in Single Skeletal Muscle Fibers from Heart Failure Patients

    PubMed Central

    DiFranco, Marino; Quiñonez, Marbella; Shieh, Perry; Fonarow, Gregg C.; Cruz, Daniel; Deng, Mario C.; Vergara, Julio L.; Middlekauff, Holly R.

    2014-01-01

    Background Exercise intolerance in chronic heart failure (HF) has been attributed to abnormalities of the skeletal muscles. Muscle function depends on intact excitation-contraction coupling (ECC), but ECC studies in HF models have been inconclusive, due to deficiencies in the animal models and tools used to measure calcium (Ca2+) release, mandating investigations in skeletal muscle from HF patients. The purpose of this study was to test the hypothesis that Ca2+ release is significantly impaired in the skeletal muscle of HF patients in whom exercise capacity is severely diminished compared to age-matched healthy volunteers. Methods and Findings Using state-of-the-art electrophysiological and optical techniques in single muscle fibers from biopsies of the locomotive vastus lateralis muscle, we measured the action potential (AP)-evoked Ca2+ release in 4 HF patients and 4 age-matched healthy controls. The mean peak Ca2+ release flux in fibers obtained from HF patients (10±1.2 µM/ms) was markedly (2.6-fold) and significantly (p<0.05) smaller than in fibers from healthy volunteers (28±3.3 µM/ms). This impairment in AP-evoked Ca2+ release was ubiquitous and was not explained by differences in the excitability mechanisms since single APs were indistinguishable between HF patients and healthy volunteers. Conclusions These findings prove the feasibility of performing electrophysiological experiments in single fibers from human skeletal muscle, and offer a new approach for investigations of myopathies due to HF and other diseases. Importantly, we have demonstrated that one step in the ECC process, AP-evoked Ca2+ release, is impaired in single muscle fibers in HF patients. PMID:25310188

  3. The origin, and application of somatosensory evoked potentials as a neurophysiological technique to investigate neuroplasticity

    PubMed Central

    Passmore, Steven R.; Murphy, Bernadette; Lee, Timothy D.

    2014-01-01

    Somatosensory evoked potentionals (SEPs) can be used to elucidate differences in cortical activity associated with a spinal manipulation (SM) intervention. The purpose of this narrative review is to overview the origin and application of SEPs, a neurophysiological technique to investigate neuroplasticity. Summaries of: 1) parameters for SEP generation and waveform recording; 2) SEP peak nomenclature, interpretation and generators; 3) peaks pertaining to tactile information processing (relevant to both chiropractic and other manual therapies); 4) utilization and application of SEPs; 5) SEPs concurrent with an experimental task and at baseline/control/pretest; 6) SEPs pain studies; and 7) SEPs design (pre/post) and neural reorganization/neuroplasticity; and 8) SEPs and future chiropractic research are all reviewed. Understanding what SEPs are, and their application allows chiropractors, educators, and other manual therapists interested in SM to understand the context, and importance of research findings from SM studies that involve SEPs. PMID:24932021

  4. The Vestibular-Auditory Interaction for Auditory Brainstem Response to Low Frequencies

    PubMed Central

    Gohari, Nasrin

    2014-01-01

    Since saccular projection is sound sensitive, the objective is to investigate the possibility that the saccular projections may contribute to auditory brainstem response to 500?HZ tone burst (ABR500?HZ). During the case-control research, twenty healthy controls compared to forty selected case groups as having chronic and resistant BPPV were evaluated in the audiology department of Hamadan University of Medical Sciences (Hamadan, Iran). Assessment is comprised of audiologic examinations, cervical vestibular evoked myogenic potentials (cVEMPs), and ABR500?HZ. We found that forty affected ears of BPPV patients with decreased vestibular excitability as detected by abnormal cVEMPs had abnormal results in ABR500?HZ, whereas unaffected ears presented normal findings. Multiple comparisons of mean p13, n23 latencies, and peak-to-peak amplitudes between three groups (affected, unaffected, and healthy ears) were significant. In conclusion, the saccular nerves can be projective to auditory bundles and interact with auditory brainstem response to low frequencies. Combine the cVEMPs and ABR500?HZ in battery approach tests of vestibular assessment and produce valuable data for judgment on the site of lesion. Regarding vestibular cooperation for making of wave V, it is reasonable that the term of ABR500?HZ is not adequate and the new term or vestibular-auditory brainstem response to 500?HZ tone burst is more suitable. PMID:25006510

  5. Contribution of Vestibular-Evoked Myogenic Potential (VEMP) testing in the assessment and the differential diagnosis of otosclerosis

    PubMed Central

    Tramontani, Ourania; Gkoritsa, Eleni; Ferekidis, Eleftherios; Korres, Stavros G.

    2014-01-01

    Background The aim of this prospective clinical study was to evaluate the clinical importance of Vestibular-Evoked Myogenic Potentials (VEMPs) in the assessment and differential diagnosis of otosclerosis and otologic diseases characterized by “pseudo-conductive” components. We also investigated the clinical appearance of balance disorders in patients with otosclerosis by correlating VEMP results with the findings of caloric testing and pure tone audiometry(PTA). Material/Methods Air-conducted(AC) 4-PTA, bone-conducted(BC) 4-PTA, air-bone Gap(ABG), AC, BC tone burst evoked VEMP, and calorics were measured preoperatively in 126 otosclerotic ears. Results The response rate of the AC-VEMPs and BC-VEMPs was 29.36% and 44.03%, respectively. Statistical differences were found between the means of ABG, AC 4-PTA, and BC 4-PTA in the otosclerotic ears in relation to AC-VEMP elicitability. About one-third of patients presented with disequilibrium. A statistically significant interaction was found between calorics and dizziness in relation to PTA thresholds. No relationship was found between calorics and dizziness with VEMPs responses. Conclusions AC and BC VEMPs can be elicited in ears with otosclerosis. AC-VEMP is more vulnerable to conductive hearing loss. Evaluation of AC-VEMP thresholds can be added in the diagnostic work-up of otosclerosis in case of doubt, enhancing differential diagnosis in patients with air-bone gaps. Otosclerosis is not a cause of canal paresis or vertigo. PMID:24509900

  6. In-Air Evoked Potential Audiometry of Grey Seals (Halichoerus grypus) from the North and Baltic Seas

    PubMed Central

    Ruser, Andreas; Dähne, Michael; Sundermeyer, Janne; Lucke, Klaus; Houser, Dorian S.; Finneran, James J.; Driver, Jörg; Pawliczka, Iwona; Rosenberger, Tanja; Siebert, Ursula

    2014-01-01

    In-air anthropogenic sound has the potential to affect grey seal (Halichoerus grypus) behaviour and interfere with acoustic communication. In this study, a new method was used to deliver acoustic signals to grey seals as part of an in-air hearing assessment. Using in-ear headphones with adapted ear inserts allowed for the measurement of auditory brainstem responses (ABR) on sedated grey seals exposed to 5-cycle (2-1-2) tone pips. Thresholds were measured at 10 frequencies between 1–20 kHz. Measurements were made using subcutaneous electrodes on wild seals from the Baltic and North Seas. Thresholds were determined by both visual and statistical approaches (single point F-test) and good agreement was obtained between the results using both methods. The mean auditory thresholds were ?40 dB re 20 µPa peak equivalent sound pressure level (peSPL) between 4–20 kHz and showed similar patterns to in-air behavioural hearing tests of other phocid seals between 3 and 20 kHz. Below 3 kHz, a steep reduction in hearing sensitivity was observed, which differed from the rate of decline in sensitivity obtained in behavioural studies on other phocids. Differences in the rate of decline may reflect influence of the ear inserts on the ability to reliably transmit lower frequencies or interference from the structure of the distal end of the ear canal. PMID:24632891

  7. In-air evoked potential audiometry of grey seals (Halichoerus grypus) from the North and Baltic Seas.

    PubMed

    Ruser, Andreas; Dähne, Michael; Sundermeyer, Janne; Lucke, Klaus; Houser, Dorian S; Finneran, James J; Driver, Jörg; Pawliczka, Iwona; Rosenberger, Tanja; Siebert, Ursula

    2014-01-01

    In-air anthropogenic sound has the potential to affect grey seal (Halichoerus grypus) behaviour and interfere with acoustic communication. In this study, a new method was used to deliver acoustic signals to grey seals as part of an in-air hearing assessment. Using in-ear headphones with adapted ear inserts allowed for the measurement of auditory brainstem responses (ABR) on sedated grey seals exposed to 5-cycle (2-1-2) tone pips. Thresholds were measured at 10 frequencies between 1-20 kHz. Measurements were made using subcutaneous electrodes on wild seals from the Baltic and North Seas. Thresholds were determined by both visual and statistical approaches (single point F-test) and good agreement was obtained between the results using both methods. The mean auditory thresholds were ?40 dB re 20 µPa peak equivalent sound pressure level (peSPL) between 4-20 kHz and showed similar patterns to in-air behavioural hearing tests of other phocid seals between 3 and 20 kHz. Below 3 kHz, a steep reduction in hearing sensitivity was observed, which differed from the rate of decline in sensitivity obtained in behavioural studies on other phocids. Differences in the rate of decline may reflect influence of the ear inserts on the ability to reliably transmit lower frequencies or interference from the structure of the distal end of the ear canal. PMID:24632891

  8. Respiration-modulated membrane potential and chemosensitivity of locus coeruleus neurones in the in vitro brainstem-spinal cord of the neonatal rat.

    PubMed

    Oyamada, Y; Ballantyne, D; Mückenhoff, K; Scheid, P

    1998-12-01

    1. The activity of locus coeruleus (LC) neurones (n = 126) was examined in whole-cell (conventional and amphotericin B-perforated patch) recordings, and the relationship of this activity to the respiratory discharge recorded on the C4 or C5 phrenic nerve roots was determined at different CO2 concentrations (2 and 8 %; bath pH 7. 8 and 7.2) in the in vitro brainstem-spinal cord preparation of the neonatal rat (1-5 days old). 2. In most neurones (n = 105) ongoing activity was modulated at respiratory frequency. Typically, this consisted of a phase of depolarization and increased discharge frequency synchronous with the phrenic burst, followed by a phase of hyperpolarization and inhibition of discharge (n = 94 of 105). The incidence of respiratory modulation decreased from 91 % on P1 to 57 % on P5. 3. Bath application of the non-NMDA receptor antagonist 6-cyano-7-nitroquinoxaline-2,3-dione (CNQX; 5 microM) or the NMDA receptor antagonist DL-2-amino-5-phosphonovaleric acid (APV; 100 microM) abolished both phases of respiratory modulation. The hyperpolarizing phase alone was abolished by the adrenoceptor antagonists idazoxan (5 microM) or phentolamine (0.8 microM). These results indicate that excitatory amino acid pathways are involved in the transmission of both the excitatory and inhibitory components and that the latter involves in addition an alpha2-adrenoceptor-mediated pathway. 4. Increasing the CO2 concentration from 2 to 8 % resulted in a shortening of expiratory duration and weakening or loss of respiratory-phased inhibition; this was accompanied by depolarization, increased discharge frequency and, in those neurones where they were initially present (60 %), an increase in the frequency of subthreshold membrane potential oscillations. The depolarizing response was retained in the presence of tetrodotoxin (TTX, 0.2-1.0 microM). 5. These results indicate that in this neonatal preparation LC neurones form part of the synaptically connected brainstem respiratory network, and that the LC constitutes a site of CO2- or pH-dependent chemoreception. PMID:9806990

  9. Innovative neurophysiological methods in itch research: long-latency evoked potentials after electrical and thermal stimulation in patients with atopic dermatitis.

    PubMed

    Yudina, Marina M; Toropina, Galina G; Lvov, Andrey; Gieler, Uwe

    2011-10-01

    The aim of this study was to examine the findings of innovative neurophysiological methods of itch research. Short-latency and pain-related somatosensory-evoked potentials after electrical stimulation, as well as long-latency evoked potentials after thermal stimulation were studied in 38 patients with atopic dermatitis (AD) and 26 healthy volunteers. Quantitative Sensory Testing of thermal perception was performed in 22 patients with AD from the main AD group and in 15 healthy volunteers. Brain hyperactivity to electrical stimuli, delayed thermal-evoked potentials and elevated thermal thresholds were revealed in patients with AD compared with healthy controls. The data indicate small nerve fibre dysfunction in patients with AD, which may contribute to the pathogenesis of AD and chronic itch. The study demonstrates objective approaches to assess the function of small nerve fibres in patients with chronic itch. PMID:21710104

  10. A new method for registration of kinesthetic evoked potentials for studies of proprioceptive sensitivity in normal subjects and patients with organic lesions in the brain.

    PubMed

    Gordeev, S A; Voronin, S G

    2015-01-01

    The proprioceptive sensitivity of healthy volunteers and convalescents after acute cerebrovascular episodes was studied by a new neurophysiological method for registration of kinesthetic evoked potentials emerging in response to passive 50(o) bending of the hand in the wrist joint with the angular acceleration of 350 rad/sec(2). Kinesthetic evoked potentials were recorded above the somatosensory cortex projection areas in the hemispheres contra- and ipsilateral to the stimulated limb. The patients exhibited significantly longer latencies and lesser amplitudes of the early components of response in the involved hemisphere in comparison with normal subjects. The method for registration of the kinesthetic evoked potentials allows a more detailed study of the mechanisms of kinesthetic sensitivity in health and in organic involvement of the brain. PMID:25567199

  11. RAT AND HUMAN VISUAL-EVOKED POTENTIALS RECORDED UNDER COMPARABLE CONDITIONS: A PRELIMINARY ANALYSIS TO ADDRESS THE ISSUE OF PREDICTING HUMAN NEUROTOXIC EFFECTS

    EPA Science Inventory

    A search was undertaken for contributions of sustained and transient visual elements to the rat visual-evoked potential (VEP) using procedures similar to those used in humans (Hudnell et al., in preparation). voked potentials were recorded following either pattern-reversal or pat...

  12. Pain-related somatosensory evoked potentials and functional brain magnetic resonance in the evaluation of neurologic recovery after cardiac arrest: a case study of three patients

    PubMed Central

    2012-01-01

    This case series investigates whether painful electrical stimulation increases the early prognostic value of both somatosensory-evoked potentials and functional magnetic resonance imaging in comatose patients after cardiac arrest. Three single cases with hypoxic-ischemic encephalopathy were considered. A neurophysiological evaluation with an electroencephalogram and somatosensory-evoked potentials during increased electrical stimulation in both median nerves was performed within five days of cardiac arrest. Each patient also underwent a functional magnetic resonance imaging evaluation with the same neurophysiological protocol one month after cardiac arrest. One patient, who completely recovered, showed a middle latency component at a high intensity of stimulation and the activation of all brain areas involved in cerebral pain processing. One patient in a minimally conscious state only showed the cortical somatosensory response and the activation of the primary somatosensory cortex. The last patient, who was in a vegetative state, did not show primary somatosensory evoked potentials; only the activation of subcortical brain areas occurred. These preliminary findings suggest that the pain-related somatosensory evoked potentials performed to increase the prognosis of comatose patients after cardiac arrest are associated with regional brain activity showed by functional magnetic resonance imaging during median nerves electrical stimulation. More importantly, this cases report also suggests that somatosensory evoked potentials and functional magnetic resonance imaging during painful electrical stimulation may be sensitive and complementary methods to predict the neurological outcome in the acute phase of coma. Thus, pain-related somatosensory-evoked potentials may be a reliable and a cost-effective tool for planning the early diagnostic evaluation of comatose patients. PMID:22463985

  13. 12 WEEK EXPOSURE TO CARBONYL SULFIDE PRODUCES BRAIN LESIONS AND CHANGES IN BRAINSTEM AUDITORY (BAER) AND SOMATOSENAORY (SEP) EVOKED POTENTIALS IN FISCHER 344N RATS

    EPA Science Inventory

    Carbonyl sulfide (COS) is a chemical intermediate in the production of pesticides and herbicides, is a metabolite of carbon disulfide, is produced by the combustion of organic material, and is found occurring in nature. COS was included in a Toxic Substances Control Act request f...

  14. INHALATIONAL EXPOSURE TO CARBONYL SULFIDE (COS) PRODUCES BRAIN LESIONS AND ALTERED BRAINSTEM AUDITORY (BAER) AND SOMATOSENSORY (SEP) EVOKED POTENTIALS IN FISHCER 344N RATS.

    EPA Science Inventory

    Because of the amount of carbonyl sulfide (COS) emissions and the lack of toxicological data, COS was listed in the Clean Air Act of 1990 as a Hazardous Air Pollutant. In 1999 COS was nominated by the US EPA to the National Toxicology Program for additional toxicological investig...

  15. Solid and hollow pedicle screws affect the electrical resistance: A potential source of error with stimulus-evoked electromyography

    PubMed Central

    Wang, Hongwei; Liao, Xinhua; Ma, Xianguang; Li, Changqing; Han, Jianda; Zhou, Yue

    2013-01-01

    Background: Although stimulus evoked electromyography (EMG) is commonly used to confirm the accuracy of pedicle screw placement. There are no studies to differentiate between solid screws and hollow screws to the electrical resistance of pedicle screws. We speculate that the electrical resistance of the solid and hollow pedicle screws may be different and then a potential source of error with stimulus-evoked EMG may happen. Materials and Methods: Resistance measurements were obtained from 12 pedicle screw varieties (6 screws of each manufacturer) across the screw shank based on known constant current and measured voltage. The voltage was measured 5 times at each site. Results: Resistance of all solid screws ranged from 0.084 ? to 0.151 ? (mean =0.118 ± 0.024 ?) and hollow screws ranged from 0.148 ? to 0.402 ? (mean = 0.285 ± 0.081 ?). There was a significant difference of resistance between the solid screws and hollow screws (P < 0.05). The screw with the largest diameter no matter solid screws or hollow screws had lower resistance than screws with other diameters. No matter in solid screws group or hollow screws group, there were significant differences (P < 0.05) between the 5.0 mm screws and 6.0 mm screws, 6.0 mm screws and 7.0 mm screws, 5.0 mm screws and 7.0 mm screws, 4.5 mm screws and 5.5 mm screws, 5.5 mm screws and 6.5 mm screws, 4.5 mm screws and 6.5 mm screws. The resistance of hollow screws was much larger than the solid screws in the same diameter group (P < 0.05). Conclusions: Hollow pedicle screws have the potential for high electrical resistance compared to the solid pedicle screws and therefore may affect the EMG response during stimulus-evoked EMG testing in pedicle screw fixation especially in minimally invasive percutaneous pedical screw fixation surgery. PMID:23960278

  16. [Visual evoked potentials produced by monocular flash stimuli in the cerebral cortex of the rabbit. I. Typography].

    PubMed

    Pérez-Cobo, J C; Ruiz-Beramendi, M; Pérez-Arroyo, M

    1990-12-01

    The visually evoked potentials in the hemisphere contralateral to the stimulated eye in rabbit, can be described topographically as follows. While a positive wave (P1) begins forming in the anterior zones and in the V I binocular zone, the N0 wave, at times very large, is produced in a more occipital zone, which corresponds to the visual streak. Immediately afterwards, the positivity, P1, practically invades the whole of the hemisphere. After this, the N1 wave which is produced in the most posterior parts of the V I, begins forming. The whole phenomenon comes to an end when the P2 wave is generated in the most occipital zones. PMID:2099533

  17. Effects of rotation on the sleep state-dependent midlatency auditory evoked P50 potential in the human

    NASA Technical Reports Server (NTRS)

    Dornhoffer, John L.; Mamiya, N.; Bray, P.; Skinner, Robert D.; Garcia-Rill, Edgar

    2002-01-01

    Sopite syndrome, characterized by loss of initiative, sensitivity to normally innocuous sensory stimuli, and impaired concentration amounting to a sensory gating deficit, is commonly associated with Space Motion Sickness (SMS). The amplitude of the P50 potential is a measure of level of arousal, and a paired-stimulus paradigm can be used to measure sensory gating. We used the rotary chair to elicit the sensory mismatch that occurs with SMS by overstimulating the vestibular apparatus. The effects of rotation on the manifestation of the P50 midlatency auditory evoked response were then assessed as a measure of arousal and distractibility. Results showed that rotation-induced motion sickness produced no change in the level of arousal but did produce a significant deficit in sensory gating, indicating that some of the attentional and cognitive deficits observed with SMS may be due to distractibility induced by decreased habituation to repetitive stimuli.

  18. Continuous somatosensory evoked potentials monitoring is highly sensitive to intraoperative occlusion of iliac artery during anterior lumbar interbody fusion: case report.

    PubMed

    Haghighi, S S; Zhang, R; Raiszadeh, R; Chammas, J; Bench, G; Raiszadeh, K; Terramanis, T T

    2009-01-01

    We report a case of thrombotic occlusion of the left common iliac artery during an L5-S1 anterior interbody fusion exposed via a retroperitoneal approach. The loss of distal blood flow was detected by loss of cortical and peripheral somatosensory evoked potentials on the left lower extremity. Restoration of the blood flow resulted in gradual return of evoked potentials of the involved extremity. The neurophysiological and pulse oximetry monitoring of the lower extremities are extremely sensitive for an early detection of thrombotic occlusions and vascular complications. PMID:19694209

  19. Resting state in Alzheimer's disease: a concurrent analysis of Flash-Visual Evoked Potentials and quantitative EEG

    PubMed Central

    2012-01-01

    Background To investigate to what extent Alzheimer's Disease (AD) affects Resting State activity, the possible impairment of independent electrophysiological parameters was determined in Eye-open and Eye-closed Conditions. Specifically, Flash-Visual Evoked Potential (F-VEP) and quantitative EEG (q-EEG) were examined to establish whether abnormalities of the former were systematically associated with changes of the latter. Methods Concurrently recorded F-VEP and q-EEG were comparatively analysed under Eye-open and Eye-closed Conditions in 11 Controls and 19 AD patients presenting a normal Pattern-Visual Evoked Potential (P-VEP). Between Condition differences in latencies of P2 component were matched to variations in spectral components of q-EEG. Results P2 latency increased in 10 AD patients with Abnormal Latency (AD-AL) under Eye-closed Condition. In these patients reduction of alpha activity joined an increased delta power so that their spectral profile equated that recorded under Eye-open Condition. On the opposite, in Controls as well as in AD patients with Normal P2 Latency (AD-NL) spectral profiles recorded under Eye-open and Eye-closed Conditions significantly differed from each other. At the baseline, under Eye-open Condition, the spectra overlapped each other in the three Groups. Conclusion Under Eye-closed Condition AD patients may present a significant change in both F-VEP latency and EEG rhythm modulation. The presence of concurrent changes of independent parameters suggests that the neurodegenerative process can impair a control system active in Eye-closed Condition which the electrophysiological parameters depend upon. F-VEP can be viewed as a reliable marker of such impairment. PMID:23190493

  20. Effects of dimethylarsinic and dimethylarsinous acid on evoked synaptic potentials in hippocampal slices of young and adult rats

    SciTech Connect

    Krueger, Katharina [Institut fuer Physiologie I, Universitaetsklinikum Muenster, Robert-Koch-Strasse 27a, D-48149 Muenster (Germany)], E-mail: katharina.krueger@uni-muenster.de; Repges, Hendrik [Institut fuer Physiologie I, Universitaetsklinikum Muenster, Robert-Koch-Strasse 27a, D-48149 Muenster (Germany); Hippler, Joerg; Hartmann, Louise M.; Hirner, Alfred V. [Institut fuer Umweltanalytik, Universitaet Duisburg-Essen, Universitaetsstrasse 3-5, D-45141 Essen (Germany); Straub, Heidrun [Institut fuer Physiologie I, Universitaetsklinikum Muenster, Robert-Koch-Strasse 27a, D-48149 Muenster (Germany); Binding, Norbert [Institut fuer Arbeitsmedizin, Universitaetsklinikum Muenster, Robert-Koch-Strasse 51, D-48149 Muenster (Germany); Musshoff, Ulrich [Institut fuer Physiologie I, Universitaetsklinikum Muenster, Robert-Koch-Strasse 27a, D-48149 Muenster (Germany)

    2007-11-15

    In this study, the effects of pentavalent dimethylarsinic acid ((CH{sub 3}){sub 2}AsO(OH); DMA{sup V}) and trivalent dimethylarsinous acid ((CH{sub 3}){sub 2}As(OH); DMA{sup III}) on synaptic transmission generated by the excitatory Schaffer collateral-CA1 synapse were tested in hippocampal slices of young (14-21 day-old) and adult (2-4 month-old) rats. Both compounds were applied in concentrations of 1 to 100 {mu}mol/l. DMA{sup V} had no effect on the amplitudes of evoked fEPSPs or the induction of LTP recorded from the CA1 dendritic region either in adult or in young rats. However, application of DMA{sup III} significantly reduced the amplitudes of evoked fEPSPs in a concentration-dependent manner with a total depression following application of 100 {mu}mol/l DMA{sup III} in adult and 10 {mu}mol/l DMA{sup III} in young rats. Moreover, DMA{sup III} significantly affected the LTP-induction. Application of 10 {mu}mol/l DMA{sup III} resulted in a complete failure of the postsynaptic potentiation of the fEPSP amplitudes in slices taken both from adult and young rats. The depressant effect was not reversible after a 30-min washout of the DMA{sup III}. In slices of young rats, the depressant effects of DMA{sup III} were more pronounced than in those taken from adult ones. Compared to the (absent) effect of DMA{sup V} on synaptic transmission, the trivalent compound possesses a considerably higher neurotoxic potential.

  1. Kappa opioid receptor activation potentiates the cocaine-induced increase in evoked dopamine release recorded in vivo in the mouse nucleus accumbens.

    PubMed

    Ehrich, Jonathan M; Phillips, Paul E M; Chavkin, Charles

    2014-12-01

    Behavioral stressors increase addiction risk in humans and increase the rewarding valence of drugs of abuse including cocaine, nicotine and ethanol in animal models. Prior studies have established that this potentiation of drug reward was mediated by stress-induced release of the endogenous dynorphin opioids and subsequent kappa opioid receptor (KOR) activation. In this study, we used in vivo fast scan cyclic voltammetry to test the hypothesis that KOR activation before cocaine administration might potentiate the evoked release of dopamine from ventral tegmental (VTA) synaptic inputs to the nucleus accumbens (NAc) and thereby increase the rewarding valence of cocaine. The KOR agonist U50488 inhibited dopamine release evoked by either medial forebrain bundle (MFB) or pedunculopontine tegmental nucleus (PPTg) activation of VTA inputs to the shell or core of the mouse NAc. Cocaine administration increased the dopamine response recorded in either the shell or core evoked by either MFB or PPTg stimulation. Administration of U50488 15 min before cocaine blocked the conditioned place preference (CPP) to cocaine, but only significantly reduced the effect of cocaine on the dopamine response evoked by PPTg stimulation to NAc core. In contrast, administration of U50488 60 min before cocaine significantly potentiated cocaine CPP and significantly increased the effects of cocaine on the dopamine response evoked by either MFB or PPTg stimulation, recorded in either NAc shell or core. Results of this study support the concept that stress-induced activation of KOR by endogenous dynorphin opioids may enhance the rewarding valence of drugs of abuse by potentiating the evoked dopamine response. PMID:24971603

  2. Effect of interstimulus interval and age on cortical auditory evoked potentials in 10-22-week-old infants.

    PubMed

    Sharma, Mridula; Johnson, Patrice K H; Purdy, Suzanne C; Norman, Farah

    2014-03-01

    This study compares cortical auditory evoked potentials (CAEPs) at different interstimulus intervals (ISIs) in infants to determine the impact of stimulus rate on wave morphology. Infant CAEPs are dominated by a positive peak P1. We hypothesized that infant CAEPs would be more adult-like at longer ISI with P1, followed by negativity (labelled N450). Participants were 10 typically developing infants aged 10-13 weeks (N=4) and 20-22 weeks (N=6). CAEPs were measured in one recording session for /da/ in quiet at 55 dB SPL for ISIs of 910, 1820, 3640 and 4550 ms in a randomized order. Recordings were complete at each ISI for 7-10 infants. Seven infants who completed all testing in quiet were also tested in continuous white noise (+5 dB signal-to-noise ratio) for the shortest ISI. P1 was observable in all infants; N450 was only present in the older infants. There appeared to be no ISI effect for younger or older infants, which is not consistent with ISI findings for adults and older children. The presence of N450 in the older infants only suggests that cortical maturational differences are evident in speech-evoked CAEPs in young infants. There were minimal effects of noise on P1 latency and amplitude. Results suggest different effects of ISI for very young infants than those observed in older infants and children. CAEPs are being used to measure hearing aid effectiveness in young infants and hence it is imperative that the effects of factors such as ISI are better understood. PMID:24323125

  3. Multichannel recordings of the human brainstem frequency-following response: Scalp topography, source generators, and distinctions from the transient ABR.

    PubMed

    Bidelman, Gavin M

    2015-05-01

    Brainstem frequency-following responses (FFRs) probe the neural transcription of speech/music, auditory disorders, and plasticity in subcortical auditory function. Despite clinical and empirical interest, the response's neural basis remains poorly understood. The current study aimed to more fully characterize functional properties of the human FFR (topography, source locations, generation). Speech-evoked FFRs were recorded using a high-density (64 channel) electrode montage. Source dipole modeling and 3-channel Lissajous analysis was used to localize the most likely FFR generators and their orientation trajectories. Additionally, transient auditory brainstem responses (ABRs), recorded in the same listeners, were used to predict FFRs and test the long-held assumption that the sustained potential reflects a series of overlapping onset responses. Results showed that FFRs were maximal at frontocentral scalp locations with obliquely oriented sources from putative generators in the midbrain (i.e., upper brainstem). Comparisons between derived and actual recordings revealed the FFR is not a series of repeated ABR wavelets and thus, represents a functionally distinct brainstem response. FFRs recorded at temporal electrode sites showed larger amplitudes and contained higher frequency components than vertex channels (Fz, Cz) suggesting that FFRs measured near the mastoid are generated more peripherally (auditory nerve) than measurements at frontocentral scalp locations. Furthermore, this reveals the importance of choice in reference electrode location for FFR interpretation. Our findings provide non-invasive evidence that (i) FFRs reflect sustained neural activity whose sources are consistent with rostral brainstem generators and (ii) FFRs are functionally distinct from the onset ABR response. PMID:25660195

  4. Source analysis of short and long latency vestibular-evoked potentials (VsEPs) produced by left vs. right ear air-conducted 500 Hz tone pips

    PubMed Central

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

    2014-01-01

    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. PMID:24699384

  5. Sensory evoked potentials in unanesthetized unrestrained cuttlefish: a new preparation for brain physiology in cephalopods

    Microsoft Academic Search

    Theodore H. Bullock; Bernd U. Budelmann

    1991-01-01

    Up to five microelectrodes inserted through short hypodermic needles in the cranial cartilage of Sepia officinalis recorded potentials while the cuttlefish moved freely in a small enclosure. Compound field potentials and unit spikes were seen during ongoing, spontaneous activity and after sensory stimulation.

  6. Enhancement of Auditory-evoked Potentials in Musicians Reflects an Influence of Expertise but not Selective Attention

    Microsoft Academic Search

    Simon Baumann; Martin Meyer; Lutz Jäncke

    2008-01-01

    Instrumental tones and, in some instances, simple sine-wave tones were shown to evoke stronger auditory-evoked responses in musicians compared to nonmusicians. This effect was taken as an example for plasticity in the auditory cortex elicited by training. To date, however, it is unknown whether an enlarged cortical representation for (instrumental) tones or increased neuronal activity provoked by focused attention in

  7. Auditory and Visual P300 Evoked Potentials Do Not Predict Response to Valproate Treatment of Aggression in Patients with Borderline and Antisocial Personality Disorders

    Microsoft Academic Search

    Roy R. Reeves; Frederick A. Struve; Gloria Patrick

    2005-01-01

    In this study of patients with borderline personality disorder (BPD) or antisocial personality disorder (ASPD) hospitalized because of aggressive behavior, auditory and visual P300 evoked potentials were obtained prior to treatment with valproate. Eight ASPD patients (8 males, 0 females) and 11 BPD patients (2 males, 9 females) showed improvement, while in 7 patients with ASPD (7 males, 0 females)

  8. DEPRESSION OF THE PHOTIC AFTER DISCHARGE OF FLASH EVOKED POTENTIALS BY PHYSOSTIGMINE, CARBARYL AND PROPOXUR AND THE RELATIONSHIP TO INHIBITION OF BRAIN CHOLINESTERASE

    EPA Science Inventory

    The effects of N-methyl carbamate pesticides on the photic after discharge (PhAD) of flash evoked potentials (FEPs) and the relationship between inhibition of brain cholinesterase (ChE) activity and the PhAD were evaluated. FEPs were recorded in Long Evans rats treated with physo...

  9. BRAIN CHOLINESTERASE INHIBITION PRODUCED BY PROPOXUR AND DEPRESSION OF THE PHOTIC AFTER DISCHARGE OF FLASH EVOKED POTENTIALS IN LONG EVANS RATS.

    EPA Science Inventory

    Propoxur is a widely used N-methyl carbamate pesticide that acts by inhibiting cholinesterases (ChE), which may lead to cholinergic toxicity. Flash evoked potentials (FEPs) are a neurophysiological response following stimulation of the visual system with flashes of light. They ar...

  10. Boundary Element Method-Based Cortical Potential Imaging of Somatosensory Evoked Potentials Using Subjects' Magnetic Resonance Images

    Microsoft Academic Search

    B. He; X. Zhang; J. Lian; H. Sasaki; D. Wu; V. L. Towle

    2002-01-01

    A boundary element method-based cortical potential imaging technique has been developed to directly link the scalp potentials with the cortical potentials with the aid of magnetic resonance images of the subjects. First, computer simulations were conducted to evaluate the new approach in a concentric three-sphere inhomogeneous head model. Second, the corresponding cortical potentials were estimated from the patients' preoperative scalp

  11. Odor-evoked oxygen consumption by action potential and synaptic transmission in the olfactory bulb

    PubMed Central

    Lecoq, Jérôme; Tiret, Pascale; Najac, Marion; Shepherd, Gordon M.; Greer, Charles A.; Charpak, Serge

    2009-01-01

    The relationship between metabolism of neuronal activity, microvascular organization and blood flow dynamics is critical for interpreting functional brain imaging. Here we used the rat dorsal olfactory bulb as a model to determine in vivo the correlation between action potential propagation, synaptic transmission, oxygen consumption and capillary density during odor stimulation. We find that capillary lumen occupies about 3 % of the glomerular volume, where synaptic transmission occurs, and only 0.1 % of the overlying nerve layer. In glomeruli, odor triggers a local early decrease in tissue oxygen partial pressure that results principally from dendritic activation rather than from firing of axon terminals, transmitter release or astrocyte activation. In the nerve layer, action potential propagation does not generate local changes in tissue oxygen partial pressure. We conclude that capillary density is tightly correlated with the oxidative metabolism of synaptic transmission, and suggest that action potential propagation operates mainly anaerobically. PMID:19193889

  12. Auditory rhythms entrain visual processes in the human brain: Evidence from evoked oscillations and event-related potentials.

    PubMed

    Escoffier, Nicolas; Herrmann, Christoph S; Schirmer, Annett

    2015-05-01

    Temporal regularities in the environment are thought to guide the allocation of attention in time. Here, we explored whether entrainment of neuronal oscillations underpins this phenomenon. Participants viewed a regular stream of images in silence, or in-synchrony or out-of-synchrony with an unmarked beat position of a slow (1.3Hz) auditory rhythm. Focusing on occipital recordings, we analyzed evoked oscillations shortly before and event-related potentials (ERPs) shortly after image onset. The phase of beta-band oscillations in the in-synchrony condition differed from that in the out-of-synchrony and silence conditions. Additionally, ERPs revealed rhythm effects for a stimulus onset potential (SOP) and the N1. Both were more negative for the in-synchrony as compared to the out-of-synchrony and silence conditions and their amplitudes positively correlated with the beta phase effects. Taken together, these findings indicate that rhythmic expectations are supported by a reorganization of neural oscillations that seems to benefit stimulus processing at expected time points. Importantly, this reorganization emerges from global rhythmic cues, across modalities, and for frequencies significantly higher than the external rhythm. As such, our findings support the idea that entrainment of neuronal oscillations represents a general mechanism through which the brain uses predictive elements in the environment to optimize attention and stimulus perception. PMID:25701698

  13. Effects of ketamine and propofol on motor evoked potentials elicited by intracranial microstimulation during deep brain stimulation

    PubMed Central

    Furmaga, Havan; Park, Hyun-Joo; Cooperrider, Jessica; Baker, Kenneth B.; Johnson, Matthew; Gale, John T.; Machado, Andre G.

    2014-01-01

    Few preclinical or clinical studies have evaluated the effect of anesthetics on motor evoked potentials (MEPs), either alone or in the presence of conditioning stimuli such as deep brain stimulation (DBS). In this study we evaluated the effects of two commonly used anesthetic agents, propofol and ketamine (KET), on MEPs elicited by intra-cortical microstimulation of the motor cortex in a rodent model with and without DBS of the dentatothalamocortical (DTC) pathway. The effects of propofol anesthesia on MEP amplitudes during DTC DBS were found to be highly dose dependent. Standard, but not high, dose propofol potentiated the facilitatory effects of 30 Hz DTC DBS on MEPs. This facilitation was sustained and phase-dependent indicating that, compared to high dose propofol, standard dose propofol has a beta-band excitatory effect on cortical networks. In contrast, KET anesthetic demonstrated a monotonic relationship with increasing frequencies of stimulation, such that the highest frequency of stimulation resulted in the greatest MEP amplitude. KET also showed phase dependency but less pronounced than standard dose propofol. The results underscore the importance of better understanding the complex effects of anesthetics on cortical networks and exogenous stimuli. Choice of anesthetic agents and dosing may significantly confound or even skew research outcomes, including experimentation in novel DBS indications and paradigms. PMID:24904312

  14. Origins of the short latency somatosensory evoked potentials in cat--with special reference to the sensory relay nuclei.

    PubMed

    Ryu, H; Uemura, K

    1988-11-01

    In order to identify the generators of short latency somatosensory evoked potential (SL-SEP) components, we studied, in cats, the relationship between the latencies of SL-SEP components and those of action potentials travelling along the somatosensory pathway. We also studied the changes of SL-SEPs after small lesions at various levels along the pathway. In the record with a noncephalic reference, four positive peaks (PI, PII, PIII, PIV) and three negative peaks (NI, NII, NIII) were identified. Two to three small negative waves (III-a, III-b, III-c) were superimposed on the waves from PIII to NIII. We concluded as follows: (i) NIII is a near-field component originating in the primary somatosensory cortex. (ii) III-a, III-b, and III-c originate between the decussation of the medial lemniscus and the thalamus. (iii) PIII probably originates from multiple structures rostral and caudal to the decussation of the medial lemniscus. PII, NII, and a part of PIII may originate in the region where C6 to T1 dorsal roots enter the spinal cord. (iv) The earliest components or PI and NI originate in the peripheral nerve at the axilla. (v) No components of SL-SEP originating at the dorsal root ganglia, dorsal column nuclei, thalamic VPL nucleus, or cerebellum were identified. (vi) Most of the SL-SEP components may originate where the volume conductor geometry or the impedance of the conducting medium changes suddenly. PMID:3181355

  15. House dust mite potentiates capsaicin-evoked Ca2+ transients in mouse pulmonary sensory neurons via activation of protease-activated receptor-2

    PubMed Central

    Gu, Qihai; Lee, Lu-Yuan

    2011-01-01

    House dust mite (HDM) is a major source of allergen in house dust and has been suggested to be involved in the pathogenesis of asthma. In this study, we aimed to investigate whether HDM can modulate the sensitivity of pulmonary sensory neurons, and if so, to elucidate the underlying mechanism. Fura-2 based ratiometric Ca2+ imaging was carried out to determine the effect of HDM extract on the capsaicin-evoked Ca2+ transient in mouse vagal pulmonary sensory neurons. Pretreatment with HDM (50 ?g/ml, 5 min) significantly enhanced the Ca2+ transient evoked by capsaicin in these neurons isolated from wildtype mice. This potentiating effect of HDM was not antagonized by E-64, a selective cysteine protease inhibitor, but was completely prevented by AEBSF, a specific serine protease inhibitor. In addition, the potentiating effect of HDM on capsaicin-evoked Ca2+ transient was absent in the pulmonary sensory neurons isolated from protease-activated receptor-2 (PAR2) knockout mice. Further, the sensitizing effect of HDM was completely abolished by U73122, a PLC inhibitor, or chelerythrine, a PKC inhibitor. In summary, our results demonstrate that HDM, mainly through its serine protease activity, potentiates capsaicin-evoked Ca2+ transient in mouse pulmonary sensory neurons via the activation of PAR2 and PLC-PKC intracellular transduction cascade. PMID:22125310

  16. Estimating regional brain activity from evoked potential fields on the scalp

    Microsoft Academic Search

    R. Srebro; R. M. Oguz; K. Hughlett; P. D. Purdy

    1993-01-01

    Potential fields on the surface of the brain were estimated from discretely sampled scalp fields in human subjects. Relatively simple methods of linear algebra were combined with detailed anatomical information from magnetic resonance imaging. The method was verified using a tank model of the human head that encased a fully hydrated human skull in a polymer matrix of controlled resistivity

  17. Cortical Sources of the Early Components of the Visual Evoked Potential

    E-print Network

    Sereno, Martin

    - ate cortex within the calcarine fissure comes from studies showing that the C1 reverses in polarity et al., 1995; Mangun, 1995). This reversal corresponds to the retinotopic organization of the striate potentials of opposite polarity. Such a pattern would not be observed for VEPs generated in other visual

  18. Cortical Reorganization in Dyslexic Children after Phonological Training: Evidence from Early Evoked Potentials

    ERIC Educational Resources Information Center

    Spironelli, Chiara; Penolazzi, Barbara; Vio, Claudio; Angrilli, Alessandro

    2010-01-01

    Brain plasticity was investigated in 14 Italian children affected by developmental dyslexia after 6 months of phonological training. The means used to measure language reorganization was the recognition potential, an early wave, also called N150, elicited by automatic word recognition. This component peaks over the left temporo-occipital cortex…

  19. Visual Perception and Frontal Lobe in Intellectual Disabilities: A Study with Evoked Potentials and Neuropsychology

    ERIC Educational Resources Information Center

    Munoz-Ruata, J.; Caro-Martinez, E.; Perez, L. Martinez; Borja, M.

    2010-01-01

    Background: Perception disorders are frequently observed in persons with intellectual disability (ID) and their influence on cognition has been discussed. The objective of this study is to clarify the mechanisms behind these alterations by analysing the visual event related potentials early component, the N1 wave, which is related to perception…

  20. Functional MRI brain imaging studies using the Contact Heat Evoked Potential Stimulator (CHEPS) in a human volunteer topical capsaicin pain model

    PubMed Central

    Shenoy, Ravikiran; Roberts, Katherine; Papadaki, Anastasia; McRobbie, Donald; Timmers, Maarten; Meert, Theo; Anand, Praveen

    2011-01-01

    Acute application of topical capsaicin produces spontaneous burning and stinging pain similar to that seen in some neuropathic states, with local hyperalgesia. Use of capsaicin applied topically or injected intradermally has been described as a model for neuropathic pain, with patterns of activation in brain regions assessed using functional magnetic resonance imaging (fMRI) and positron emission tomography. The Contact Heat Evoked Potential Stimulator (CHEPS) is a noninvasive clinically practical method of stimulating cutaneous A-delta nociceptors. In this study, topical capsaicin (1%) was applied to the left volar forearm for 15 minutes of twelve adult healthy human volunteers. fMRI scans and a visual analog pain score were recorded during CHEPS stimulation precapsaicin and postcapsaicin application. Following capsaicin application there was a significant increase in visual analog scale (mean ± standard error of the mean; precapsaicin 26.4 ± 5.3; postcapsaicin 48.9 ± 6.0; P < 0.0001). fMRI demonstrated an overall increase in areas of activation, with a significant increase in the contralateral insular signal (mean ± standard error of the mean; precapsaicin 0.434 ± 0.03; postcapsaicin 0.561 ± 0.07; P = 0.047). The authors of this paper recently published a study in which CHEPS-evoked A-delta cerebral potential amplitudes were found to be decreased postcapsaicin application. In patients with neuropathic pain, evoked pain and fMRI brain responses are typically increased, while A-delta evoked potential amplitudes are decreased. The protocol of recording fMRI following CHEPS stimulation after topical application of capsaicin could be combined with recording of evoked potentials to provide a simple, rapid, and robust volunteer model to develop novel drugs for neuropathic pain. PMID:22090805

  1. [Short-latency brain stem evoked potentials to acoustic stimulation in closed craniocerebral trauma in children].

    PubMed

    Kriuchko, V I; Berestov, A I; Khondkarian, G Sh; Sumerkina, M M; Sepp, E K

    1989-01-01

    Twenty-six children with closed craniocerebral trauma (CCCT) of various severity were examined by recording short-latent stem-induced potentials in response to acoustic stimulation. Prognostical authenticity of the method in severe CCCT in children was established, which allowed reversible and irreversible disorders of brain them function to be distinguished. Studies in dynamics made it possible to follow the course of the pathological process and correct the applied therapy in time. PMID:2750394

  2. The Effect of Odour Priming on Long Latency Visual Evoked Potentials of Matching and Mismatching Objects

    Microsoft Academic Search

    Joanne Grigor; Steve Van Toller; John Behan; Anne Richardson

    1999-01-01

    This study reports a cross-modal, olfactory\\/visual event related potential (ERP) using odours as olfactory primes. The results show a difference in the ERP waveform for the N400 waveform when a visual image does not match the priming odour. An N400 peak was produced for both the matched and mismatched conditions but the peaks were significantly more negative for the mismatched

  3. Attention to emotion: auditory-evoked potentials in an emotional choice reaction task and personality traits as assessed by the NEO FFI

    Microsoft Academic Search

    Verena Mittermeier; Gregor Leicht; Susanne Karch; Ulrich Hegerl; Hans-Jürgen Möller; Oliver Pogarell; Christoph Mulert

    2011-01-01

    Several studies suggest that attention to emotional content is related to specific changes in central information processing.\\u000a In particular, event-related potential (ERP) studies focusing on emotion recognition in pictures and faces or word processing\\u000a have pointed toward a distinct component of the visual-evoked potential, the EPN (‘early posterior negativity’), which has\\u000a been shown to be related to attention to emotional

  4. Generating Visual Flickers for Eliciting Robust Steady-State Visual Evoked Potentials at Flexible Frequencies Using Monitor Refresh Rate

    PubMed Central

    Nakanishi, Masaki; Wang, Yijun; Wang, Yu-Te; Mitsukura, Yasue; Jung, Tzyy-Ping

    2014-01-01

    In the study of steady-state visual evoked potentials (SSVEPs), it remains a challenge to present visual flickers at flexible frequencies using monitor refresh rate. For example, in an SSVEP-based brain-computer interface (BCI), it is difficult to present a large number of visual flickers simultaneously on a monitor. This study aims to explore whether or how a newly proposed frequency approximation approach changes signal characteristics of SSVEPs. At 10 Hz and 12 Hz, the SSVEPs elicited using two refresh rates (75 Hz and 120 Hz) were measured separately to represent the approximation and constant-period approaches. This study compared amplitude, signal-to-noise ratio (SNR), phase, latency, scalp distribution, and frequency detection accuracy of SSVEPs elicited using the two approaches. To further prove the efficacy of the approximation approach, this study implemented an eight-target BCI using frequencies from 8–15 Hz. The SSVEPs elicited by the two approaches were found comparable with regard to all parameters except amplitude and SNR of SSVEPs at 12 Hz. The BCI obtained an averaged information transfer rate (ITR) of 95.0 bits/min across 10 subjects with a maximum ITR of 120 bits/min on two subjects, the highest ITR reported in the SSVEP-based BCIs. This study clearly showed that the frequency approximation approach can elicit robust SSVEPs at flexible frequencies using monitor refresh rate and thereby can largely facilitate various SSVEP-related studies in neural engineering and visual neuroscience. PMID:24918435

  5. Ocular vestibular evoked myogenic potentials induced by bone-conducted vibration in patients with unilateral inner ear disease

    PubMed Central

    Ogawa, Yasuo; Hagiwara, Akira; Otsuka, Koji; Inagaki, Taro; Shimizu, Shigetaka; Suzuki, Mamoru

    2014-01-01

    Conclusion Patients with vestibular neuritis (VN) with complete canal paresis (CP) showed a higher rate of abnormal ocular vestibular evoked myogenic potential (oVEMP) than those with partial CP. From these results, it is speculated that the superior vestibular nerve function mainly affects oVEMP. Significant correlation was found between the grades of the hearing outcome and oVEMP in sudden sensorineural hearing loss (SSHL). Objective We attempted to correlate the results of oVEMP with the results of cervical VEMP (cVEMP), results of subjective visual vertical (SVV), and clinical course in patients with various vestibular disorders. Methods Twenty-two patients with VN, 65 with SSHL, and 22 with Meniere's disease (MD), were enrolled in this study. We compared the results of oVEMP with those of cVEMP, SVV, and the caloric test. Furthermore, the oVEMP results were compared with the initial hearing threshold, presence of vertigo, and hearing recovery in the patients with SSHL. Results The patients with VN with complete CP showed a higher rate of abnormal oVEMP than those with partial CP. In the patients with SSHL, the hearing recovery rate was lower in the patients with abnormal oVEMP than in those with normal oVEMP. PMID:24215219

  6. Intelligence as a factor in evoked potential studies of psychopathology. I. Comparison of low and high IQ subjects.

    PubMed

    Shagass, C; Roemer, R A; Straumanis, J J; Josiassen, R C

    1981-11-01

    To evaluate possible influences of differences in intelligence on evoked potential (EP) relations to psychopathology, EPs of subjects with high and low scores on Raven's Progressive Matrices were compared. EPs to left median nerve (LSEP), right median nerve (RSEP), visual (VEP), and auditory (AEP) stimul were recorded from 15 leads. EPs of age- and sex-matched high and low IQ nonpatients (7 of each) and psychiatric patients (40 of each) were compared with respect to group mean EPs, amplitude, latency, and wave-shape stability measures; high and low IQ patients were also matched for diagnosis. Certain differences between high and low IQ subjects were common to both patients and nonpatients; lower IQ was associated with (i) higher early (before 100 msec) LSEP and RSEP amplitudes; (ii) lower later LSEP amplitudes; (iii) less late epoch LSEP wave-shape stability; (iv) less VEP wave-shape stability. Since these EP characteristics resemble deviations from normal reported for psychotics, intelligence differences could account for part, but by no means all, of the psychopathology-related EP differences. The relationship to IQ of the EP contour length ("string") measure, reported by Hendrickson and Hendrickson to be highly correlated with IQ, was also assessed; results were negative. PMID:7349616

  7. Generating visual flickers for eliciting robust steady-state visual evoked potentials at flexible frequencies using monitor refresh rate.

    PubMed

    Nakanishi, Masaki; Wang, Yijun; Wang, Yu-Te; Mitsukura, Yasue; Jung, Tzyy-Ping

    2014-01-01

    In the study of steady-state visual evoked potentials (SSVEPs), it remains a challenge to present visual flickers at flexible frequencies using monitor refresh rate. For example, in an SSVEP-based brain-computer interface (BCI), it is difficult to present a large number of visual flickers simultaneously on a monitor. This study aims to explore whether or how a newly proposed frequency approximation approach changes signal characteristics of SSVEPs. At 10 Hz and 12 Hz, the SSVEPs elicited using two refresh rates (75 Hz and 120 Hz) were measured separately to represent the approximation and constant-period approaches. This study compared amplitude, signal-to-noise ratio (SNR), phase, latency, scalp distribution, and frequency detection accuracy of SSVEPs elicited using the two approaches. To further prove the efficacy of the approximation approach, this study implemented an eight-target BCI using frequencies from 8-15 Hz. The SSVEPs elicited by the two approaches were found comparable with regard to all parameters except amplitude and SNR of SSVEPs at 12 Hz. The BCI obtained an averaged information transfer rate (ITR) of 95.0 bits/min across 10 subjects with a maximum ITR of 120 bits/min on two subjects, the highest ITR reported in the SSVEP-based BCIs. This study clearly showed that the frequency approximation approach can elicit robust SSVEPs at flexible frequencies using monitor refresh rate and thereby can largely facilitate various SSVEP-related studies in neural engineering and visual neuroscience. PMID:24918435

  8. [A wireless smart home system based on brain-computer interface of steady state visual evoked potential].

    PubMed

    Zhao, Li; Xing, Xiao; Guo, Xuhong; Liu, Zehua; He, Yang

    2014-10-01

    Brain-computer interface (BCI) system is a system that achieves communication and control among humans and computers and other electronic equipment with the electroencephalogram (EEG) signals. This paper describes the working theory of the wireless smart home system based on the BCI technology. We started to get the steady-state visual evoked potential (SSVEP) using the single chip microcomputer and the visual stimulation which composed by LED lamp to stimulate human eyes. Then, through building the power spectral transformation on the LabVIEW platform, we processed timely those EEG signals under different frequency stimulation so as to transfer them to different instructions. Those instructions could be received by the wireless transceiver equipment to control the household appliances and to achieve the intelligent control towards the specified devices. The experimental results showed that the correct rate for the 10 subjects reached 100%, and the control time of average single device was 4 seconds, thus this design could totally achieve the original purpose of smart home system. PMID:25764705

  9. Athletic training in badminton players modulates the early C1 component of visual evoked potentials: a preliminary investigation.

    PubMed

    Jin, Hua; Xu, Guiping; Zhang, John X; Ye, Zuoer; Wang, Shufang; Zhao, Lun; Lin, Chong-De; Mo, Lei

    2010-12-01

    One basic question in brain plasticity research is whether individual life experience in the normal population can affect very early sensory-perceptual processing. Athletes provide a possible model to explore plasticity of the visual cortex as athletic training in confrontational ball games is quite often accompanied by training of the visual system. We asked professional badminton players to watch video clips related to their training experience and predict where the ball would land and examined whether they differed from non-player controls in the elicited C1, a visual evoked potential indexing V1 activity. Compared with controls, the players made judgments significantly more accurately, albeit not faster. An early ERP component peaking around 65 ms post-stimulus with a scalp topography centering at the occipital pole (electrode Oz) was observed in both groups and interpreted as the C1 component. With comparable latency, amplitudes of this component were significantly enhanced for the players than for the non-players, suggesting that it can be modulated by long-term physical training. The results present a clear case of experience-induced brain plasticity in primary visual cortex for very early sensory processing. PMID:20854849

  10. The Alaris auditory evoked potential monitor as an indicator of seizure inducibility and duration during electroconvulsive therapy: an observational study

    PubMed Central

    2014-01-01

    Background Precise control of anesthetic depth during electroconvulsive therapy (ECT) is crucial because most intravenous anesthetics have anticonvulsant effects. In this study, we investigated the association between anesthetic depth measured by the Alaris auditory evoked potential index (AAI) and seizure inducibility and seizure duration during ECT. Methods Sixty-four ECTs were evaluated in 12 consecutive patients. General anesthesia was performed with a thiopental-based method. The relationship between the pre-ictal AAI, seizure activity and seizure duration was analyzed, and a possible threshold pre-ictal AAI to induce a seizure duration of at least 25 seconds was calculated. Results Forty-one of the 64 ECT stimuli successfully induced seizure activity that lasted longer than 25 seconds. Pre-ictal AAI was significantly correlated to seizure duration (r?=?0.54, p?

  11. Pre-movement facilitation of motor-evoked potentials in man during transcranial stimulation of the central motor pathways.

    PubMed

    Rossini, P M; Zarola, F; Stalberg, E; Caramia, M

    1988-08-16

    Motor evoked potentials (MEPs) following trans-cranial stimulation (TCS) through unifocal electric or magnetic impulses have been evaluated in the pre-movement period in 8 healthy volunteers. By utilizing a simple reaction time paradigm, progressive amplitude increments and latency decrements of MEPs have been demonstrated in the 100 ms preceding the onset of EMG activity in the muscle examined. By employing surface and depth recordings from various muscles of hand and forearm contralateral to the TCS, it was observed that in the 'early' period of pre-EMG facilitation (100-60 ms before EMG onset) TCS solely recruited the same low-threshold motor units which are fired first during self-paced contractions. In the 'middle and late' epochs of pre-EMG facilitation, TCS served when MEPs were recorded from a relaxed muscle, during TCS of progressively higher intensity. Multiple muscle recordings showed that pre-EMG facilitation was remarkably limited to the muscular group of the hand primarily involved in the intended movement. PMID:3208099

  12. The steady-state visual evoked potential reveals neural correlates of the items encoded into visual working memory.

    PubMed

    Peterson, Dwight J; Gurariy, Gennadiy; Dimotsantos, Gabriella G; Arciniega, Hector; Berryhill, Marian E; Caplovitz, Gideon P

    2014-10-01

    Visual working memory (VWM) capacity limitations are estimated to be ~4 items. Yet, it remains unclear why certain items from a given memory array may be successfully retrieved from VWM and others are lost. Existing measures of the neural correlates of VWM cannot address this question because they measure the aggregate processing of the entire stimulus array rather than neural signatures of individual items. Moreover, this cumulative processing is usually measured during the delay period, thereby reflecting the allocation of neural resources during VWM maintenance. Here, we use the steady-state visual evoked potential (SSVEP) to identify the neural correlates of individual stimuli at VWM encoding and test two distinct hypotheses: the focused-resource hypothesis and the diffuse-resource hypothesis, for how the allocation of neural resources during VWM encoding may contribute to VWM capacity limitations. First, we found that SSVEP amplitudes were larger for stimuli that were later remembered than for items that were subsequently forgotten. Second, this pattern generalized so that the SSVEP amplitudes were also larger for the unprobed stimuli in correct compared to incorrect trials. These data are consistent with the diffuse-resource view in which attentional resources are broadly allocated across the whole stimulus array. These results illustrate the important role encoding mechanisms play in limiting the capacity of VWM. PMID:25173712

  13. Audiogram of a formerly stranded long-finned pilot whale (Globicephala melas) measured using auditory evoked potentials.

    PubMed

    Pacini, A F; Nachtigall, P E; Kloepper, L N; Linnenschmidt, M; Sogorb, A; Matias, S

    2010-09-15

    Long-finned pilot whales are highly social odontocetes found in temperate and subpolar regions. This species is particularly known for its interaction with fisheries as well as its mass strandings. Recent tagging work has provided some information about pilot whales in the wild but, even though they have been successfully kept in captivity, little is known about their sensory capabilities. This study investigates the hearing abilities of a rehabilitated 2 year old male long-finned pilot whale. A complete audiogram was collected using auditory evoked potential techniques that included measurements of nine frequencies from 4 to 100 kHz presented as sinusoidally amplitude-modulated tones. The results indicated that the region of best hearing was between 11.2 and 50 kHz and the subject had relatively poor high frequency hearing compared with other odontocete species. This study emphasizes the importance of collecting basic hearing measurements from new species, understanding diagnostic life histories as well as continuously increasing the sample size of audiometry measurements within and between odontocete species as animals become available. PMID:20802115

  14. Steady-state visual evoked potentials in the low frequency range in migraine: a study of habituation and variability phenomena.

    PubMed

    de Tommaso, Marina; Stramaglia, Sebastiano; Schoffelen, Jan Mathijs; Guido, Marco; Libro, Giuseppe; Losito, Luciana; Sciruicchio, Vittorio; Sardaro, Michele; Pellicoro, Mario; Puca, Franco Michele

    2003-08-01

    Previous studies have revealed that migraine patients display an increased photic driving to flash stimuli in the medium frequency range. The aim of this study was to perform a topographic analysis of steady-state visual evoked potentials (SVEPs) in the low frequency range (3-9 Hz), evaluating the temporal behaviour of the F1 amplitude by investigating habituation and variability phenomena. The main component of SVEPs, the F1, demonstrated an increased amplitude in several channels at 3 Hz. Behaviour of F1 amplitude was rather variable over time, and the wavelet-transform standard deviation was increased in migraine patients at a low stimulus rate. The discriminative value of the F1 mean amplitude and variability index, tested by both an artificial neural network classifier and a support vector machine, were high according to both methods. The increased photic driving in migraine should be subtended by a more generic abnormality of visual reactivity instead of a selective impairment of a visual subsystem. Temporal behaviour of SVEPs is not influenced by a clear tendency to habituation, but the F1 amplitude seemed to change in a complex way, which is better described by variability phenomena. An increased variability in response to flicker stimuli in migraine patients could be interpreted as an overactive regulation mechanism, prone to instability and consequently to headache attacks, whether spontaneous or triggered. PMID:12919718

  15. Nitroglycerin induces migraine headache and central sensitization phenomena in patients with migraine without aura: a study of laser evoked potentials.

    PubMed

    de Tommaso, Marina; Libro, Giuseppe; Guido, Marco; Difruscolo, Olimpia; Losito, Luciana; Sardaro, Michele; Cerbo, Rosanna

    2004-06-17

    In migraineurs nitroglycerin (NTG) induces severe delayed headache, resembling spontaneous migraine attacks. The aim of the present study was to evaluate NTG laser evoked potentials (LEP) features amplitude and pain sensation to laser stimuli during NTG-induced headache. Nine patients were selected. Headache was induced by oral administration of 0.6 mg of NTG; signals were recorded through disk electrodes placed at the vertex and referred to linked earlobes. CO(2)-LEPs delivered by stimulation of the dorsum of both hands and the right and left supraorbital zones were evaluated after the onset of moderate or severe headache resembling spontaneous migraine and at least 72 h after the end of the headache phase. Patients exhibited a significant heat pain threshold reduction and an LEPs amplitude increment during headache when both the supraorbital zones were stimulated. NTG appeared to support a reliable experimental model of migraine, based on the neuronal effects on the integrative-nociceptive structures. The LEPs facilitation during NTG-induced headache may be subtended by a hyperactivity of nociceptive cortex as well as by a failure of pain-inhibitory control. PMID:15182958

  16. Frequency-doubling technology perimetry and multifocal visual evoked potential in glaucoma, suspected glaucoma, and control patients

    PubMed Central

    Kanadani, Fabio N; Mello, Paulo AA; Dorairaj, Syril K; Kanadani, Tereza CM

    2014-01-01

    Introduction The gold standard in functional glaucoma evaluation is standard automated perimetry (SAP). However, SAP depends on the reliability of the patients’ responses and other external factors; therefore, other technologies have been developed for earlier detection of visual field changes in glaucoma patients. The frequency-doubling perimetry (FDT) is believed to detect glaucoma earlier than SAP. The multifocal visual evoked potential (mfVEP) is an objective test for functional evaluation. Objective To evaluate the sensitivity and specificity of FDT and mfVEP tests in normal, suspect, and glaucomatous eyes and compare the monocular and interocular mfVEP. Methods Ninety-five eyes from 95 individuals (23 controls, 33 glaucoma suspects, 39 glaucomatous) were enrolled. All participants underwent a full ophthalmic examination, followed by SAP, FDT, and mfVEP tests. Results The area under the curve for mean deviation and pattern standard deviation were 0.756 and 0.761, respectively, for FDT, 0.564 and 0.512 for signal and alpha for interocular mfVEP, and 0.568 and 0.538 for signal and alpha for monocular mfVEP. This difference between monocular and interocular mfVEP was not significant. Conclusion The FDT Matrix was superior to mfVEP in glaucoma detection. The difference between monocular and interocular mfVEP in the diagnosis of glaucoma was not significant. PMID:25075173

  17. Recording evoked potentials during deep brain stimulation: development and validation of instrumentation to suppress the stimulus artefact

    PubMed Central

    Kent, A R; Grill, W M

    2012-01-01

    Deep brain stimulation (DBS) is an effective treatment for movement disorders, but the selection of stimulus parameters is a clinical burden and often yields sub-optimal outcomes for patients. Measurement of electrically evoked compound action potentials (ECAPs) during DBS could offer insight into the type and spatial extent of neural element activation and provide a potential feedback signal for the rational selection of stimulus parameters and closed-loop DBS. However, recording ECAPs presents a significant technical challenge due to the large stimulus artefact, which can saturate recording amplifiers and distort short latency ECAP signals. We developed DBS-ECAP recording instrumentation combining commercial amplifiers and circuit elements in a serial configuration to reduce the stimulus artefact and enable high fidelity recording. We used an electrical circuit equivalent model of the instrumentation to understand better the sources of the stimulus artefact and the mechanisms of artefact reduction by the circuit elements. In vitro testing validated the capability of the instrumentation to suppress the stimulus artefact and increase gain by a factor of 1,000 to 5,000 compared to a conventional biopotential amplifier. The distortion of mock ECAP (mECAP) signals was measured across stimulation parameters, and the instrumentation enabled high fidelity recording of mECAPs with latencies of only 0.5 ms for DBS pulse widths of 50 to 100 ?s/phase. Subsequently, the instrumentation was used to record in vivo ECAPs, without contamination by the stimulus artefact, during thalamic DBS in an anesthetized cat. The characteristics of the physiological ECAP were dependent on stimulation parameters. The novel instrumentation enables high fidelity ECAP recording and advances the potential use of the ECAP as a feedback signal for the tuning of DBS parameters. PMID:22510375

  18. Recording evoked potentials during deep brain stimulation: development and validation of instrumentation to suppress the stimulus artefact

    NASA Astrophysics Data System (ADS)

    Kent, A. R.; Grill, W. M.

    2012-06-01

    The clinical efficacy of deep brain stimulation (DBS) for the treatment of movement disorders depends on the identification of appropriate stimulation parameters. Since the mechanisms of action of DBS remain unclear, programming sessions can be time consuming, costly and result in sub-optimal outcomes. Measurement of electrically evoked compound action potentials (ECAPs) during DBS, generated by activated neurons in the vicinity of the stimulating electrode, could offer insight into the type and spatial extent of neural element activation and provide a potential feedback signal for the rational selection of stimulation parameters and closed-loop DBS. However, recording ECAPs presents a significant technical challenge due to the large stimulus artefact, which can saturate recording amplifiers and distort short latency ECAP signals. We developed DBS-ECAP recording instrumentation combining commercial amplifiers and circuit elements in a serial configuration to reduce the stimulus artefact and enable high fidelity recording. We used an electrical circuit equivalent model of the instrumentation to understand better the sources of the stimulus artefact and the mechanisms of artefact reduction by the circuit elements. In vitro testing validated the capability of the instrumentation to suppress the stimulus artefact and increase gain by a factor of 1000 to 5000 compared to a conventional biopotential amplifier. The distortion of mock ECAP (mECAP) signals was measured across stimulation parameters, and the instrumentation enabled high fidelity recording of mECAPs with latencies of only 0.5 ms for DBS pulse widths of 50 to 100 µs/phase. Subsequently, the instrumentation was used to record in vivo ECAPs, without contamination by the stimulus artefact, during thalamic DBS in an anesthetized cat. The characteristics of the physiological ECAP were dependent on stimulation parameters. The novel instrumentation enables high fidelity ECAP recording and advances the potential use of the ECAP as a feedback signal for the tuning of DBS parameters.

  19. Evoked potential augmenting-reducing in psychopaths and criminals with impaired smooth-pursuit eye movements.

    PubMed

    Raine, A; Venables, P H

    1990-01-01

    Previous studies that have assessed a stimulation-seeking theory of psychopathy are open to the criticism that psychopaths may lie on self-report questionnaires. The present study uses event-related potential (ERP) augmenting-reducing as a psychophysiological analog of stimulation-seeking in psychopaths to test this theory. It is also hypothesized that "schizoid" criminals, as defined by poor eye tracking, would show nonaugmenting/reducing, a profile characteristic of schizophrenia. Schizoid criminals were found to be characterized by nonaugmenting/reducing, but psychopaths were not found to be characterized by augmenting. It is concluded that stimulation-seeking is a viable theory of criminality but not of psychopathy, and that the etiological basis to schizoid criminality may differ substantially from criminality, per se. PMID:2315424

  20. Spontaneous emotion regulation: Differential effects on evoked brain potentials and facial muscle activity.

    PubMed

    Baur, Ramona; Conzelmann, Annette; Wieser, Matthias J; Pauli, Paul

    2015-04-01

    Late positive potentials (LPPs) were found to be decreased during down-regulation and increased during up-regulation of positive and negative emotions. However, previous studies lack ecological validity, since they explicitly instructed their participants to use certain regulation strategies. The goal of our study was to test an ecologically more valid paradigm of emotion regulation. We therefore investigated the effects of freely chosen emotion regulation strategies on LPPs and additionally assessed facial EMG responses and valence and arousal ratings as control variables. Responses to positive IAPS pictures were marked by pleasant valence ratings and high activations of M. zygomaticus major, negative pictures elicited unpleasant valence ratings and high activations of M. corrugator supercilii, and both, positive and negative pictures, went along with increased arousal ratings and LPPs. Importantly, ratings and EMG activity were intensified through up-regulation and attenuated through down-regulation of emotions, while LPPs were increased through both up-and down-regulation. We conclude that LPPs in paradigms with free choice of emotion regulation strategies might be a marker of attentional resources required for the selection of adequate emotion up- and down-regulation strategies, while LPP effects following emotion regulation with specific, instructed strategies reflect modulated arousal processes. PMID:25715271

  1. Novelty is not enough: laser-evoked potentials are determined by stimulus saliency, not absolute novelty.

    PubMed

    Ronga, I; Valentini, E; Mouraux, A; Iannetti, G D

    2013-02-01

    Event-related potentials (ERPs) elicited by transient nociceptive stimuli in humans are largely sensitive to bottom-up novelty induced, for example, by changes in stimulus attributes (e.g., modality or spatial location) within a stream of repeated stimuli. Here we aimed 1) to test the contribution of a selective change of the intensity of a repeated stimulus in determining the magnitude of nociceptive ERPs, and 2) to dissect the effect of this change of intensity in terms of "novelty" and "saliency" (an increase of stimulus intensity is more salient than a decrease of stimulus intensity). Nociceptive ERPs were elicited by trains of three consecutive laser stimuli (S1-S2-S3) delivered to the hand dorsum at a constant 1-s interstimulus interval. Three, equally spaced intensities were used: low (L), medium (M), and high (H). While the intensities of S1 and S2 were always identical (L, M, or H), the intensity of S3 was either identical (e.g., HHH) or different (e.g., MMH) from the intensity of S1 and S2. Introducing a selective change in stimulus intensity elicited significantly larger N1 and N2 waves of the S3-ERP but only when the change consisted in an increase in stimulus intensity. This observation indicates that nociceptive ERPs do not simply reflect processes involved in the detection of novelty but, instead, are mainly determined by stimulus saliency. PMID:23136349

  2. Pinprick-evoked brain potentials: a novel tool to assess central sensitization of nociceptive pathways in humans.

    PubMed

    Iannetti, G D; Baumgärtner, U; Tracey, I; Treede, R D; Magerl, W

    2013-09-01

    Although hyperalgesia to mechanical stimuli is a frequent sign in patients with inflammation or neuropathic pain, there is to date no objective electrophysiological measure for its evaluation in the clinical routine. Here we describe a technique for recording the electroencephalographic (EEG) responses elicited by mechanical stimulation with a flat-tip probe (diameter 0.25 mm, force 128 mN). Such probes activate A? nociceptors and are widely used to assess the presence of secondary hyperalgesia, a psychophysical correlate of sensitization in the nociceptive system. The corresponding pinprick-evoked potentials (PEPs) were recorded in 10 subjects during stimulation of the right and left hand dorsum before and after intradermal injection of capsaicin into the right hand and in 1 patient with a selective lesion of the right spinothalamic tract. PEPs in response to stimulation of normal skin were characterized by a vertex negative-positive (NP) complex, with N/P latencies and amplitudes of 111/245 ms and 3.5/11 ?V, respectively. All subjects developed a robust capsaicin-induced increase in the pain elicited by pinprick stimulation of the secondary hyperalgesic area (+91.5%, P < 0.005). Such stimulation also resulted in a significant increase of the N-wave amplitude (+92.9%, P < 0.005), but not of the P wave (+6.6%, P = 0.61). In the patient, PEPs during stimulation of the hypoalgesic side were reduced. These results indicate that PEPs 1) reflect cortical activities triggered by somatosensory input transmitted in A? primary sensory afferents and spinothalamic projection neurons, 2) allow quantification of experimentally induced secondary mechanical hyperalgesia, and 3) have the potential to become a diagnostic tool to substantiate mechanical hyperalgesia in patients with presumed central sensitization. PMID:23678019

  3. Effects of monomethylarsonic and monomethylarsonous acid on evoked synaptic potentials in hippocampal slices of adult and young rats

    SciTech Connect

    Krueger, Katharina [Institut fuer Physiologie I, Universitaetsklinikum Muenster, Robert-Koch-Strasse 27a, D-48149 Muenster (Germany)], E-mail: katharina.krueger@uni-muenster.de; Straub, Heidrun [Institut fuer Physiologie I, Universitaetsklinikum Muenster, Robert-Koch-Strasse 27a, D-48149 Muenster (Germany); Hirner, Alfred V.; Hippler, Joerg [Institut fuer Umweltanalytik, Universitaet Duisburg-Essen, Universitaetsstrasse 3-5, D-45141 Essen (Germany); Binding, Norbert [Institut fuer Arbeitsmedizin, Universitaetsklinikum Muenster, Robert-Koch-Strasse 51, D-48149 Muenster (Germany); Musshoff, Ulrich [Institut fuer Physiologie I, Universitaetsklinikum Muenster, Robert-Koch-Strasse 27a, D-48149 Muenster (Germany)

    2009-04-01

    Arsenite and its metabolites, dimethylarsinic or dimethylarsinous acid, have previously been shown to disturb synaptic transmission in hippocampal slices of rats (Krueger, K., Gruner, J., Madeja, M., Hartmann, L.M., Hirner, A.V., Binding, N., Mu{beta}hoff, U., 2006a. Blockade and enhancement of glutamate receptor responses in Xenopus oocytes by methylated arsenicals. Arch. Toxicol. 80, 492-501, Krueger, K., Straub, H., Binding, N., Mu{beta}hoff, U., 2006b. Effects of arsenite on long-term potentiation in hippocampal slices from adult and young rats. Toxicol. Lett. 165, 167-173, Krueger, K., Repges, H., Hippler, J., Hartmann, L.M., Hirner, A.V., Straub, H., Binding, N., Mu{beta}hoff, U., 2007. Effects of dimethylarsinic and dimethylarsinous acid on evoked synaptic potentials in hippocampal slices of young and adult rats. Toxicol. Appl. Pharmacol. 225, 40-46). The present experiments investigate, whether the important arsenic metabolites monomethylarsonic acid (MMA{sup V}) and monomethylarsonous acid (MMA{sup III}) also influence the synaptic functions of the hippocampus. In hippocampal slices of young (14-21 days-old) and adult (2-4 months-old) rats, evoked synaptic field potentials from the Schaffer collateral-CA1 synapse were measured under control conditions and during and after 30 and 60 min of application of the arsenic compounds. MMA{sup V} had no effect on the synapse functions neither in slices of adult nor in those from young rats. However, MMA{sup III} strongly influenced the synaptic transmission: it totally depressed the amplitudes of fEPSPs at concentrations of 50 {mu}mol/l (adult rats) and 25 {mu}mol/l (young rats) and LTP amplitudes at concentrations of 25 {mu}mol/l (adult rats) and 10 {mu}mol/l (young rats), respectively. In contrast, application of 1 {mu}mol/l MMA{sup III} led to an enhancement of the LTP amplitude in young rats, which is interpretable by an enhancing effect on NMDA receptors and a lack of the blocking effect on AMPA receptors at this concentration (Krueger, K., Gruner, J., Madeja, M., Hartmann, L.M., Hirner, A.V., Binding, N., Mu{beta}hoff, U., 2006a. Blockade and enhancement of glutamate receptor responses in Xenopus oocytes by methylated arsenicals. Arch. Toxicol. 80, 492-501). These effects are probably not mediated by changes in cell excitability or in presynaptic glutamate release rates, since antidromically induced population spikes and paired-pulse facilitation failed to show any MMA{sup III} effect. The impairment of the excitatory CA1 synapse is more likely caused by the action of MMA{sup III} on postsynaptic glutamatergic receptors and may be jointly responsible for dysfunctions of cognitive effects in arsenic toxicity.

  4. The dynamic allocation of attention to emotion: simultaneous and independent evidence from the late positive potential and steady state visual evoked potentials.

    PubMed

    Hajcak, Greg; MacNamara, Annmarie; Foti, Dan; Ferri, Jamie; Keil, Andreas

    2013-03-01

    Emotional stimuli capture and hold attention without explicit instruction. The late positive potential (LPP) component of the event related potential can be used to track motivated attention toward emotional stimuli, and is larger for emotional compared to neutral pictures. In the frequency domain, the steady state visual evoked potential (ssVEP) has also been used to track attention to stimuli flickering at a particular frequency. Like the LPP, the ssVEP is also larger for emotional compared to neutral pictures. Prior work suggests that both the LPP and ssVEP are sensitive to "top-down" manipulations of attention, however the LPP and ssVEP have not previously been examined using the same attentional manipulation in the same participants. In the present study, LPP and ssVEP amplitudes were simultaneously elicited by unpleasant and neutral pictures. Partway through picture presentation, participants' attention was directed toward an arousing or non-arousing region of unpleasant pictures. In line with prior work, the LPP was reduced when attention was directed toward non-arousing compared to arousing regions of unpleasant pictures; similar results were observed for the ssVEP. Thus, both electrocortical measures index affective salience and are sensitive to directed (here: spatial) attention. Variation in the LPP and ssVEP was unrelated, suggesting that these measures are not redundant with each other and may capture different neurophysiological aspects of affective stimulus processing and attention. PMID:22155660

  5. Amplitude-time characteristics of the long-latency components ( N 1, N 2, and P 300) of acoustic evoked potential in healthy subjects

    Microsoft Academic Search

    L. B. Oknina; O. A. Kuznetsova; A. P. Belostotskyi; N. L. Nechaeva; E. V. Kutakova; E. L. Masherow; A. S. Romanov

    2011-01-01

    The aim of the study was to trace the cumulative changes in the amplitude-time parameters of the AEP (acoustic evoked potential)\\u000a components N1, N2, and P300 in the experimental situations of different complexities (counting and listening to sounds) and to compare the differences\\u000a between young and mature subjects. The AEP was recorded in 12 healthy subjects aged 18 to 22

  6. The effects of ageing and sulfur dioxide inhalation exposure on visual-evoked potentials, antioxidant enzyme systems, and lipid-peroxidation levels of the brain and eye

    Microsoft Academic Search

    Derya Kilic

    2003-01-01

    The effects of ageing and 10 ppm sulfur dioxide (SO2) inhalation exposure on visual-evoked potentials (VEPs), thiobarbituric acid reactive substances (TBARS), a product of lipid peroxidation, and the activities of Cu, Zn superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), and catalase (CAT) of brain and eye were investigated in young (3-month), adult (12-month), and mature (24-month) Swiss male albino rats. The

  7. Early Motor Evoked Potentials in Acute Stroke: Adjunctive Measure to MRI for Assessment of Prognosis in Acute Stroke within 6 Hours

    Microsoft Academic Search

    Johannes C. Wöhrle; Stephan Behrens; Orell Mielke; Michael G. Hennerici

    2004-01-01

    Background: In acute stroke, a magnetic resonance (MR) perfusion-weighted imaging (PWI) and diffusion-weighted imaging (DWI) mismatch (PWI>DWI mismatch) may indicate tissue at risk for infarction and poor prognosis. However, different to early enthusiasm about this surrogate marker, its validity has shown several drawbacks in individual patients. Rather than relying on imaging, we evaluated motor evoked potentials (MEP) as a measure

  8. The role of the superior vestibular nerve in generating ocular vestibular-evoked myogenic potentials to bone conducted vibration at Fz

    Microsoft Academic Search

    S. Iwasaki; Y. Chihara; Y. E. Smulders; A. M. Burgess; G. M. Halmagyi; I. S. Curthoys; T. Murofushi

    2009-01-01

    ObjectiveThe n10 component (n10) of the ocular vestibular evoked myogenic potential (oVEMP) to brief bone conducted vibration (BCV) of the forehead at Fz is probably caused by the vibration selectively activating vestibular otolithic receptors. If the n10 is due primarily to utricular activation then diseases which affect only the superior division of the vestibular nerve (SVN) should reduce or eliminate

  9. Intraoperative somatosensory evoked potential recovery following opening of the fourth ventricle during posterior fossa decompression in Chiari malformation: case report.

    PubMed

    Grossauer, Stefan; Koeck, Katharina; Vince, Giles H

    2015-03-01

    The most appropriate surgical technique for posterior fossa decompression in Chiari malformation (CM) remains a matter of debate. Intraoperative electrophysiological studies during posterior fossa decompression of Type I CM (CM-I) aim to shed light on the entity's pathomechanism as well as on the ideal extent of decompression. The existing reports on this issue state that significant improvement in conduction occurs after craniotomy in all cases, but additional durotomy contributes a further improvement in only a minority of cases. This implies that craniotomy alone might suffice for clinical improvement without the need of duraplasty or even subarachnoid manipulation at the level of the craniocervical junction. In contrast to published data, the authors describe the case of a 32-year-old woman who underwent surgery for CM associated with extensive cervicothoracic syringomyelia and whose intraoperative somatosensory evoked potentials (SSEPs) did not notably improve after craniotomy or following durotomy; rather, they only improved after opening of the fourth ventricle and restoration of CSF flow through the foramen of Magendie. Postoperatively, the patient recovered completely from her preoperative neurological deficits. To the authors' knowledge, this is the first report of significant SSEP recovery after opening the fourth ventricle in the decompression of a CM-I. The electrophysiological and operative techniques are described in detail and the findings are discussed in the light of available literature. The authors conclude that there might be a subset of CM-I patients who require subarachnoid dissection at the level of the craniocervical junction to benefit clinically. Prospective studies with detailed electrophysiological analyses seem warranted to answer the question regarding the best surgical approach in CM-I decompression. PMID:25526275

  10. Least-squares (LS) deconvolution of a series of overlapping cortical auditory evoked potentials: a simulation and experimental study

    NASA Astrophysics Data System (ADS)

    Bardy, Fabrice; Van Dun, Bram; Dillon, Harvey; Cowan, Robert

    2014-08-01

    Objective. To evaluate the viability of disentangling a series of overlapping ‘cortical auditory evoked potentials’ (CAEPs) elicited by different stimuli using least-squares (LS) deconvolution, and to assess the adaptation of CAEPs for different stimulus onset-asynchronies (SOAs). Approach. Optimal aperiodic stimulus sequences were designed by controlling the condition number of matrices associated with the LS deconvolution technique. First, theoretical considerations of LS deconvolution were assessed in simulations in which multiple artificial overlapping responses were recovered. Second, biological CAEPs were recorded in response to continuously repeated stimulus trains containing six different tone-bursts with frequencies 8, 4, 2, 1, 0.5, 0.25 kHz separated by SOAs jittered around 150 (120-185), 250 (220-285) and 650 (620-685) ms. The control condition had a fixed SOA of 1175 ms. In a second condition, using the same SOAs, trains of six stimuli were separated by a silence gap of 1600 ms. Twenty-four adults with normal hearing (<20 dB HL) were assessed. Main results. Results showed disentangling of a series of overlapping responses using LS deconvolution on simulated waveforms as well as on real EEG data. The use of rapid presentation and LS deconvolution did not however, allow the recovered CAEPs to have a higher signal-to-noise ratio than for slowly presented stimuli. The LS deconvolution technique enables the analysis of a series of overlapping responses in EEG. Significance. LS deconvolution is a useful technique for the study of adaptation mechanisms of CAEPs for closely spaced stimuli whose characteristics change from stimulus to stimulus. High-rate presentation is necessary to develop an understanding of how the auditory system encodes natural speech or other intrinsically high-rate stimuli.

  11. Baclofen does not counteract the acute effects of ethanol on flash-evoked potentials in Long-Evans rats.

    PubMed

    Hetzler, Bruce E; Ondracek, Janie M; Becker, Elizabeth A

    2008-11-01

    This experiment examined the separate and combined effects of baclofen (5.0 mg/kg, i.p.), a GABA B receptor agonist, and ethanol (2.0 g/kg, i.p.) on flash-evoked potentials (FEPs) recorded from both the visual cortex and superior colliculus (SC) of chronically implanted male Long-Evans rats. In the visual cortex, ethanol significantly decreased the amplitude of positive component P87, but increased P37 and P47. Other component amplitudes were not significantly altered. In contrast, baclofen reduced the amplitude of negative component N31 to such an extent that it became positive. Although P47 was also reduced by baclofen, the amplitude of most other components was increased. Only P24 and P87 were unchanged by baclofen. The combination of baclofen and ethanol resulted in amplitudes very similar to ethanol alone for secondary components P47, N62, and P87, but very similar to baclofen alone for primary component N31 and late components N147 and P230. In the SC, component amplitudes were generally decreased by ethanol, baclofen, and the combination treatment. Latencies of most components in both structures were increased by the drug treatments. Each drug treatment produced significant hypothermia. Locomotor behavior was also altered. These results demonstrate: (1) pharmacological differences between the primary and late components versus the secondary components of the cortical FEP, (2) that baclofen does not counteract significant effects of ethanol on cortical or collicular component amplitudes, and (3) that baclofen enhances N147-P230 amplitude, suggesting reduced cortical arousal. PMID:18853334

  12. Effects of mecamylamine on flash-evoked potentials, body temperature, and behavior in Long-Evans rats.

    PubMed

    Hetzler, Bruce E; Beckman, Elizabeth J

    2011-02-01

    This experiment examined the effects of mecamylamine, a nicotinic acetylcholine receptor antagonist, on flash-evoked potentials (FEPs) recorded from the visual cortex (VC) and superior colliculus (SC) of chronically implanted male Long-Evans rats, and on body temperature and open field behavior. FEPs were recorded at 20 and 35 min following intraperitoneal injections of saline, and of 0.3, 3.0, and 10.0 mg/kg mecamylamine on separate days. The 0.3 mg/kg dose did not produce significant effects. The amplitude of VC components N??, P??, and P?? increased, N??? and P??? decreased, and P??, N??, N??, and N?? were unchanged following administration of the 10.0 mg/kg dose. In the SC, component P?? was unaffected, P?? was reduced, and N?? was augmented by the 10.0 mg/kg dose. All component peak latencies were increased by the 3.0 and 10.0 mg/kg doses. Significant hypothermia was also produced by the 3.0 and 10.0 mg/kg doses, suggesting that this was the basis for the increased latencies. The 10.0 mg/kg dose produced a significant decrease in movement during the recording sessions. In subsequent open field observations, both line crossings and rearings were reduced by the 3.0 and 10.0 mg/kg doses. The results suggest that endogenous acetylcholine acting on nicotinic acetylcholine receptors plays at most a modest role in producing FEPs recorded from the VC and SC. PMID:21115032

  13. Enhancement of bilateral cortical somatosensory evoked potentials to intact forelimb stimulation following thoracic contusion spinal cord injury in rats.

    PubMed

    Bazley, Faith A; Maybhate, Anil; Tan, Chuen Seng; Thakor, Nitish V; Kerr, Candace; All, Angelo H

    2014-09-01

    The adult central nervous system is capable of significant reorganization and adaptation following neurotrauma. After a thoracic contusive spinal cord injury (SCI) neuropathways that innervate the cord below the epicenter of injury are damaged, with minimal prospects for functional recovery. In contrast, pathways above the site of injury remain intact and may undergo adaptive changes in response to injury. We used cortical somatosensory evoked potentials (SSEPs) to evaluate changes in intact forelimb pathways. Rats received a midline contusion SCI, unilateral contusion SCI, or laminectomy with no contusion at the T8 level and were monitored for 28 days post-injury. In the midline injury group, SSEPs recorded from the contralateral forelimb region of the primary somatosensory cortex were 59.7% (CI 34.7%, 84.8%; c(2) = 21.9; dof = 1; p = 2.9 ×10(-6)) greater than the laminectomy group; SSEPs from the ipsilateral somatosensory cortex were 47.6% (CI 18.3%, 77%; c(2) = 10.1; dof = 1; p = 0.001) greater. Activation of the ipsilateral somatosensory cortex was further supported by BOLD-fMRI, which showed increased oxygenation at the ipsilateral hemisphere at day seven post-injury. In the unilateral injury group, ipsilesional side was compared to the contralesional side. SSEPs on day 14 (148%; CI 111%, 185%) and day 21 (137%; CI 110%, 163%) for ipsilesional forelimb stimulation were significantly increased over baseline (100%). SSEPs recorded from the hindlimb sensory cortex upon ipsilesional stimulation were 33.9% (CI 14.3%, 53.4%; c(2) = 11.6; dof = 1; p = 0.0007) greater than contralesional stimulation. Therefore, these results demonstrate the ability of SSEPs to detect significant enhancements in the activation of forelimb sensory pathways following both midline and unilateral contusive SCI at T8. Reorganization of forelimb pathways may occur after thoracic SCI, which SSEPs can monitor to aid the development of future therapies. PMID:24801738

  14. Chemotherapy for acute lymphoblastic leukemia may cause subtle changes of the spinal cord detectable by somatosensory evoked potentials.

    PubMed

    Vainionpää, L; Kovala, T; Tolonen, U; Lanning, M

    1997-01-01

    Intrathecal chemotherapy has been determined to cause transient or permanent paraparesis due to myelopathy in patients with leukemia or other malignancies. To systematically evaluate the effect of methotrexate on spinal cord function, somatosensory evoked potentials (SEP) were measured in children with acute lymphoblastic leukemia (ALL). A prospective evaluation was performed in 38 consecutive children aged 1.4-15.3 years with newly diagnosed ALL during treatment. Intrathecal methotrexate therapy was included in the therapy schedule of all patients as central nervous system (CNS) therapy in addition to intravenous chemotherapy in 19 standard risk patients and intravenous chemotherapy with cranial irradiation in 19 intermediate or high-risk patients. The measured conduction times were compared with those of 38 control children matched for age, height, and sex. A significant increase in the conduction time of the tibial nerve SEP was found between the Th12 level and the cortex in children with ALL after receiving intrathecal methotrexate therapy during the induction and CNS therapy phases when compared with their controls. The difference of the mean latencies was 1.45 ms (95% CI 0.39-2.51; P < 0.01). There was no significant delay in the median nerve SEP from the brain stem to the cortex, indicating that the conduction delay was in the area of the spinal cord exposed to intrathecal methotrexate. Moreover, the cortical amplitudes of the median nerve SEPs were significantly reduced when measured immediately after intravenous and intrathecal methotrexate and compared to the amplitudes measured after induction therapy in standard risk patients (P = 0.001). Intrathecal methotrexate with systemic chemotherapy causes a deterioration in the somatosensory pathways within the CNS, suggesting also spinal cord dysfunction in children with ALL in addition to the cerebral dysfunction described earlier. PMID:8950335

  15. Assessing the quality of steady-state visual-evoked potentials for moving humans using a mobile electroencephalogram headset

    PubMed Central

    Wang, Yijun; Wei, Chun-Shu; Jung, Tzyy-Ping

    2014-01-01

    Recent advances in mobile electroencephalogram (EEG) systems, featuring non-prep dry electrodes and wireless telemetry, have enabled and promoted the applications of mobile brain-computer interfaces (BCIs) in our daily life. Since the brain may behave differently while people are actively situated in ecologically-valid environments versus highly-controlled laboratory environments, it remains unclear how well the current laboratory-oriented BCI demonstrations can be translated into operational BCIs for users with naturalistic movements. Understanding inherent links between natural human behaviors and brain activities is the key to ensuring the applicability and stability of mobile BCIs. This study aims to assess the quality of steady-state visual-evoked potentials (SSVEPs), which is one of promising channels for functioning BCI systems, recorded using a mobile EEG system under challenging recording conditions, e.g., walking. To systematically explore the effects of walking locomotion on the SSVEPs, this study instructed subjects to stand or walk on a treadmill running at speeds of 1, 2, and 3 mile (s) per hour (MPH) while concurrently perceiving visual flickers (11 and 12 Hz). Empirical results of this study showed that the SSVEP amplitude tended to deteriorate when subjects switched from standing to walking. Such SSVEP suppression could be attributed to the walking locomotion, leading to distinctly deteriorated SSVEP detectability from standing (84.87 ± 13.55%) to walking (1 MPH: 83.03 ± 13.24%, 2 MPH: 79.47 ± 13.53%, and 3 MPH: 75.26 ± 17.89%). These findings not only demonstrated the applicability and limitations of SSVEPs recorded from freely behaving humans in realistic environments, but also provide useful methods and techniques for boosting the translation of the BCI technology from laboratory demonstrations to practical applications. PMID:24744718

  16. THE ROLE OF THE MULTIFOCAL VISUAL EVOKED POTENTIAL (MFVEP) LATENCY IN UNDERSTANDING OPTIC NERVE AND RETINAL DISEASES

    PubMed Central

    Hood, Donald C.; Chen, John Y.; Yang, E. Bo; Rodarte, Chris; Wenick, Adam S.; Grippo, Tomas M.; Odel, Jeffrey G.; Ritch, Robert

    2006-01-01

    Purpose To examine the extent to which changes in the latency of the multifocal visual evoked potential (mfVEP) overlap in patients with glaucoma, recovered optic neuritis/multiple sclerosis (ON/MS), and retinal disease. Methods Monocular mfVEPs were obtained for both eyes of all subjects. Latencies and amplitudes of individual mfVEP responses were measured using custom software and expressed relative to a normative group (n = 100). Recordings were obtained from patients with ON/MS (n = 12), glaucoma (n = 50), and retinal disease (n = 15), as well as control subjects (n = 50). All subjects had 24-2 visual fields; patients with retinal disease had multifocal electroretinograms (mfERGs). The patients with retinal disease were examined by a neuro-ophthalmologist to rule out optic nerve disease and, in general, had relatively subtle or unremarkable fundus examinations but abnormal mfERG amplitudes. Results There was considerable overlap in the latencies for the patient groups for both monocular and interocular measures of mfVEP latency. This was particularly true for the patients with retinal disease and ON/MS, for whom the range of latencies was almost identical, as was the percentage of points in the field showing significant delays. Conclusion The mfVEP delays seen in patients with retinal disease are similar in magnitude and prevalence to those seen in patients with a history of ON/MS. In general, this does not present a problem when using the mfVEP in the clinic. However, a retinal problem can be confused with ON/MS or, in fact, dismissed as functional, especially if the fundus appears normal. PMID:17471327

  17. Bulbocavernosus reflex and pudendal nerve somatosensory evoked potential are valuable for the diagnosis of cauda equina syndrome in male patients

    PubMed Central

    Niu, Xiaoting; Wang, Xun; Ni, Peiqi; Huang, Huanjie; Zhang, Yunyun; Lin, Yuanshao; Chen, Xia; Teng, Honglin; Shao, Bei

    2015-01-01

    Aims: This study is to assess the value of bulbocavernosus reflex (BCR) and pudendal nerve somatosensory evoked potential (SSEP) in the topical diagnosis of cauda equina syndrome (CES) with or without sphincter dysfunction in male patients. Methods: In this study, 40 healthy male adults (control group) and 53 male adult patients (experimental group) were included. The experimental group was subdivided into sphincter subgroup (24 patients with sphincter dysfunction) and non-sphincter subgroup (29 patients without sphincter dysfunction). All subjects underwent BCR and SSEP examinations. The mean latencies of BCR and SSEP P41 were calculated and compared between the control group and the experimental group. Latencies above the average value of +2.58S were considered abnormal. The abnormality rates of BCRs and SSEPs in sphincter and non-sphincter subgroups were calculated, respectively. Results: BCR and SSEP latencies in the experimental group were remarkably prolonged than those in the control group. BCR and SSEP latencies in sphincter subgroup were remarkably prolonged than those in non-sphincter subgroup. Among the 106 nerves in the experimental group, 87 nerves had prolonged BCR latencies and 3 nerves had no wave elicited, with an abnormality rate of 84.9%. The abnormality rates of BCR were 95.8% and 74.1% in sphincter subgroup and non-sphincter subgroup, respectively. Among the 53 nerves in the experimental group, 39 nerves had prolonged SSEP P41 latencies and 2 nerves had no wave elicited, with an abnormality rate of 77.4%. The abnormality rates of SSEP P41 were 91.7% and 65.5% in sphincter subgroup and non-sphincter subgroup, respectively. Conclusions: Both BCR and SSEP were changed in CES patients with or without sphincter dysfunction, and they were especially changed in patients with sphincter dysfunction. BCR and SSEP are valuable in the diagnosis of cauda equina lesions and their severity in males.

  18. Correlation of Transcranial Color Doppler to N20 Somatosensory Evoked Potential Detects Ischemic Penumbra in Subarachnoid Hemorrhage

    PubMed Central

    Di Pasquale, Piero; Zanatta, Paolo; Morghen, Ilaria; Bosco, Enrico; Forini, Elena

    2011-01-01

    Background: Normal subjects present interhemispheric symmetry of middle cerebral artery (MCA) mean flow velocity and N20 cortical somatosensory evoked potential (SSEP). Subarachnoid haemorrhage (SAH) can modify this pattern, since high regional brain vascular resistances increase blood flow velocity, and impaired regional brain perfusion reduces N20 amplitude. The aim of the study is to investigate the variability of MCA resistances and N20 amplitude between hemispheres in SAH. Methods: Measurements of MCA blood flow velocity (vMCA) by transcranial color-Doppler and median nerve SSEP were bilaterally performed in sixteen patients. MCA vascular changes on the compromised hemisphere were calculated as a ratio of the reciprocal of mean flow velocity (1/vMCA) to contralateral value and correlated to the simultaneous variations of interhemispheric ratio of N20 amplitude, within each subject. Data were analysed with respect to neuroimaging of MCA supplied areas. Results: Both interhemispheric ratios of 1/vMCA and N20 amplitude were detected >0.65 (p <0,01) in patients without neuroimages of injury. Both ratios became <0.65 (p <0.01) when patients showed unilateral images of ischemic penumbra and returned >0.65 if penumbra disappeared. The two ratios no longer correlated after structural lesion developed, as N20 detected in the damaged side remained pathological (ratio <0.65), whereas 1/vMCA reverted to symmetric interhemispheric state (ratio >0.65), suggesting a luxury perfusion. Conclusion: Variations of interhemispheric ratios of MCA resistance and cortical N20 amplitude correlate closely in SAH and allow identification of the reversible ischemic penumbra threshold, when both ratios become <0.65. The correlation is lost when structural damage develops. PMID:21660110

  19. Analgesic potency of a new anticonvulsant drug versus acetylsalicylic acid via laser somatosensory evoked potentials. Randomized placebo-controlled double-blind (5-way) crossover study.

    PubMed

    Schaffler, K; Wauschkuhn, C H; Gierend, M

    1991-04-01

    A randomized, double-blind crossover study was performed with three different acute oral dosages of CM 40907 (3-(4-hydroxypiperidyl)-6-(2'-chlorophenyl)-pyridazine) (600, 900 and 1200 mg), a newly developed anticonvulsant drug, vs acetylsalicylic acid (ASA, 1000 mg) and placebo in 12 male healthy volunteers to check analgesic potency. Objective algesimetry was done by Laser Somatosensory Evoked Potentials (LSEP). Subjective pain intensities were measured by retrospective visual analog scale ratings (VAS). Effects on objective vigilance were checked by Auditory Evoked Potentials (AEP). For both types of evoked potentials there was a simultaneous control of alterations in vigilance by means of the adaptive pursuit tracking task (APTT). A vigilance-controlled EEG (V-EEG) and a resting (R-EEG), visual analog scales (VAS) on sedation, excitation and anxiety as well as vital parameters (blood pressure and heart rate under supine and upright conditions) and adverse event scales were included in this trial as well. CM 40907 showed distinct analgesic effects on objective and subjective algesimetric parameters, which for the highest dosage (1200 mg) were superior in ("central") P2-amplitude suppression of LSEPs to those of ASA in ("peripheral") N1-amplitudes suppression and ongoing for more than 6 h. Subjective sedation was decreased, however, AEP-findings indicated a decreased vigilance after CM 40907. Some EEG-patterns, specifically related with CM 40907--although being ambiguous in classification terms--resembled features of benzodiazepines. Blood pressure and heart rate were raised in a clinically irrelevant manner. PMID:1859518

  20. Auditory brainstem implantation.

    PubMed

    Sennaroglu, Levent; Ziyal, Ibrahim

    2012-10-01

    The use of cochlear implants for selected individuals with bilateral severe to profound sensorineural hearing loss who derive limited benefit from conventional hearing aids is well established. There are situations where cochlear implantation is contraindicated. Auditory brainstem implantation (ABI) is the only solution to restore hearing when the cochlear nerve is disrupted together with pathologies where the cochlea does not provide a suitable location for cochlear implant. Labyrinthine and cochlear aplasia and cochlear nerve aplasia constitute the congenital indications for ABI. In the present review article history and development of ABI, indications, side selection criteria, surgery and audiological outcome are presented. PMID:22196501

  1. and Brainstem Aage R. Mller

    E-print Network

    O'Toole, Alice J.

    Cochlear and Brainstem Implants Editor Aage R. Møller Contents Introduction: Møller A.R. History of Cochlear Implants and Auditory Brainstem Implants: Møller A.R. Cochlear Implants Surgical Aspects of Cochlear Implantation: Mechanisms of Insertional Trauma: Roland P.S.; Wright C.G. Histopathology

  2. Investigation of Abnormal Left Temporal Functioning in Dyslexia through rCBF, Auditory Evoked Potentials, and Positron Emission Tomography.

    ERIC Educational Resources Information Center

    Wood, Frank; And Others

    1991-01-01

    Investigates the proposed left hemisphere dysfunction in dyslexia by reviewing four studies using regional cerebral blood flow (RCBF) and combined auditory evoked responses with positron emission tomography. Emphasizes methodological issues. Finds that dyslexics showed a positive correlation between Heschl's gyrus activation and phonemic…

  3. The Journal of Neuroscience, October 1994, 74(10): 6153-6159 Reduction of Perineal Evoked Excitatory Postsynaptic Potentials in

    E-print Network

    Manitoba, University of

    of EPSPs evoked by electrical stimulation of peripheral cutaneous afferents were mea- sured during that the micturition circuitry utilizes both premotoneuronal mechanisms and direct motoneuronal inhibition to achieve) Received Oct. 14, 1993; revised Feb. 25, 1994; accepted Apr. 13, 1994. This work was funded by an operating

  4. EVALUATING THE NMDA-GLUTAMATE RECEPTOR AS A SITE OF ACTION FOR TOLUENE USING PATTERN ELICITED VISUAL EVOKED POTENTIALS.

    EPA Science Inventory

    In vitro studies have demonstrated that toluene disrupts the function of NMDA-glutamate receptors, as well as other channels. This has led to the hypothesis that effects on NMDA receptor function may contribute to toluene neurotoxicity, CNS depression, and altered visual evoked ...

  5. Neural sensitivity to novel sounds in the rat's dorsal cortex of the inferior colliculus as revealed by evoked local field potentials.

    PubMed

    Patel, Chirag R; Redhead, Carmela; Cervi, Andrea L; Zhang, Huiming

    2012-04-01

    Evoked local field potentials in response to contralaterally presented tone bursts were recorded from the rat's dorsal cortex of the inferior colliculus (ICd). An oddball stimulus paradigm was used to study the sensitivity of ensembles of neurons in the ICd to novel sounds. Our recordings indicate that neuron ensembles in the ICd display stimulus-specific adaptation when a large contrast in both frequency and probability of occurrence exists between the two tone bursts used for generating an oddball paradigm. A local field potential evoked by a tone burst presented as a deviant stimulus has a larger amplitude than that evoked by the same sound presented as a standard stimulus. The difference between the two responses occurs after the initial rising phases of their predominant deflections. The degree of stimulus-specific adaptation increases with the rate of sound presentation up to 8/s, the highest rate used in this study. A comparison between our results and those from previous studies suggests that differences exist between responses to oddball paradigms in the ICd and those in the primary auditory cortex, a major source of projection to the ICd. These differences suggest that local mechanisms exist in the ICd for suppressing neural responses to frequently presented sounds and enhancing responses to rarely presented sounds. Thus, the ICd may serve as an important component of an integrative circuit in the brain for detecting novel sounds in the acoustic environment. PMID:22406035

  6. Disassociation of carbon disulfide-induced depression of flash-evoked potential peak N166 amplitude and norepinephrine levels.

    PubMed

    Graff, Jaimie E; Herr, David W

    2003-06-01

    Exposure to organic solvents frequently causes functional impairment of the central nervous system (CNS). One method to examine the effects of solvent exposure on visual function is flash-evoked potentials (FEPs). Greater knowledge of the role of various neurotransmitters in generating FEP peaks would be beneficial for understanding the basis of neurotoxicant-induced changes. FEP peak N166 is influenced by the psychological construct of arousal, which in turn is believed to be influenced by the function of neurons containing norepinephrine (NE). Because of its known effects on both NE and FEPs, we utilized carbon disulfide (CS2) as a means to examine the possible role of NE in modulating the amplitude of FEP peaks N36 and N166. Our hypothesis was that CS2-induced alterations in cortical NE levels would be correlated with changes in FEP peak N36 and N166 amplitudes. Adult male Long-Evans rats were implanted with electrodes over their visual cortex and allowed to recover. To develop peak N166, FEPs were recorded for two days prior to dosing. On the third day, FEPs were recorded prior to dosing, and one group of animals was sacrificed to serve as pretreatment controls. The remaining animals were dosed ip with 0 (corn oil vehicle; 2 ml/kg), 100, 200, or 400 mg/kg CS2. The treated animals were retested at 1, 4, 8, or 24 h after dosing, immediately sacrificed, and samples of the cortex, cerebellum, striatum, and brain stem were frozen for high performance liquid chromatography (HPLC) analysis of monoamine levels. Treatment with CS2 decreased peak N166 amplitude at 1 h, and peak N36 amplitude was depressed at 4 h, relative to the subject's pretreatment values. Peak latencies were increased, and colonic temperature was decreased by treatment with CS2. Exposure to CS2 depressed NE levels in the cortex, brain stem, and cerebellum 4 h after treatment. Conversely, at 4 h, levels of dopamine (DA) and its metabolite 3,4-dihydroxyphenylacetic acid were increased in the brain stem and cerebellum, and levels of the DA metabolite homovanillic acid were increased in the brain stem. Levels of serotonin were unaffected by CS2 treatment. There was a slight increase in striatal levels of the serotonin metabolite 5-hydroxyindole acetic acid at all times after treatment with CS2. There was no apparent association between the decreases in NE levels and the reductions in amplitudes for peaks N36 and N166. The neurochemical mechanism for CS2-induced reductions in FEP peak amplitudes remains to be determined. PMID:12700426

  7. The loudness dependence of the auditory evoked potential (LDAEP) as a predictor of the response to escitalopram in patients with generalized anxiety disorder

    Microsoft Academic Search

    Young-Min Park; Do-Won Kim; Sangrae Kim; Chang-Hwan Im; Seung-Hwan Lee

    2011-01-01

    Rationale  The loudness dependence of the auditory evoked potential (LDAEP) has been proposed as a potential biological marker of central\\u000a serotonergic activity. This study aimed to test the hypothesis that the LDAEP can be used to predict the response to escitalopram\\u000a in patients with GAD.\\u000a \\u000a \\u000a \\u000a \\u000a Method  Twenty-five patients with GAD were recruited. Scores on the Hamilton Anxiety Rating Scale (HAM-A), Clinical Global

  8. Rhombencephalitis / brainstem encephalitis.

    PubMed

    Jubelt, Burk; Mihai, Cornelia; Li, Terrence M; Veerapaneni, Padma

    2011-12-01

    Rhombencephalitis (RE) is a syndrome of multiple causes and multiple outcomes. Most authors now use the terms "rhombencephalitis" and "brainstem encephalitis" interchangeably even though anatomically they are slightly different. The etiologic categories of RE include infections, autoimmune diseases, and paraneoplastic syndromes (PNS). Listeria is the most common cause of infectious RE. Listeria RE primary occurs in healthy young adults. It usually occurs as a biphasic time course with a flu-like syndrome followed by brainstem dysfunction; 75% of patients have a cerebrospinal fluid (CSF) pleocytosis, and almost 100% have an abnormal brain MRI scan. Positive CSF and blood cultures are the most specific for diagnosis. Treatment primarily is with ampicillin. Enterovirus 71 is probably the second most common infectious cause of RE; however, 95% of cases have occurred in the Asian-Pacific region and there is no specific treatment. Herpes simplex virus (HSV) is the third most common infectious cause of RE, and about 80% of cases are caused by HSV1 and 20% by HSV2. About 50% only had involvement of the brainstem whereas the other 50% also had supratentorial involvement of the temporal and frontal lobes. Mortality with acyclovir treatment was 22% versus those not on acyclovir 75%. Epstein-Barr virus (EBV) and human herpesvirus 6 (HHV6) have caused a few cases. The most common autoimmune etiology is Behçet disease. Over 90% of those with Behçet RE had abnormal MRI scans and 94% had a CSF pleocytosis. Treatment is with corticosteroids and immunosuppressive agents, but only 25% have complete recovery. Paraneoplastic causes are the third category of RE. Brain MRIs are usually normal; there is usually a CSF pleocytosis but the protein is usually normal. Often anti-neuronal antibodies can be found. Prognosis is poor and treatment is only partially beneficial. Because Listeria and HSV are the most common treatable acute causes of RE, we recommend empiric therapy with ampicillin and acyclovir for all cases after samples have been obtained from CSF and blood for cultures and the polymerase chain reaction (PCR). Antibiotics can be changed based upon MRI, culture results, PCR results, and antibody studies. PMID:21956758

  9. Panic and the brainstem: clues from neuroimaging studies.

    PubMed

    Perna, Giampaolo; Guerriero, Giuseppe; Brambilla, Paolo; Caldirola, Daniela

    2014-01-01

    One of the most influential theories has conceived unexpected panic attack (PA) as a primal defensive reaction to threat within the internal milieu of the body. This theory is based on findings suggesting the involvement of dysfunctional respiratory regulation and/or abnormally sensitive central neural network of carbon dioxide (CO2)/hydrogen ion (H+) chemoreception in PA. Thus, unexpected PA may be related to phylogenetically older brain structures, including the brainstem areas, which process basic functions related to the organism's internal milieu. The brainstem represents a crucial area for homeostatic regulation, including chemoreception and cardio-respiratory control. In addition, the midbrain dorsal periaqueductal gray may be involved in the unconditioned defense reactions to proximal threats, including internal physical stimuli. Our aim was to specifically consider the potential involvement of the brainstem in panic disorder (PD) by a comprehensive review of the available neuroimaging studies. Available data are limited and potentially affected by several limitations. However, preliminary evidence of a role of the brainstem in PD can be found and, secondly, the brainstem serotonergic system seems to be involved in panic modulation with indications of both altered serotonergic receptors and 5-HT transporter bindings. In conclusion, our review suggests that the brainstem may be involved in psychopathology of PD and supports the relevant role of subcortical serotonergic system in panic pathogenesis. PMID:24923341

  10. Activation of serotonin 2A receptors underlies the psilocybin-induced effects on ? oscillations, N170 visual-evoked potentials, and visual hallucinations.

    PubMed

    Kometer, Michael; Schmidt, André; Jäncke, Lutz; Vollenweider, Franz X

    2013-06-19

    Visual illusions and hallucinations are hallmarks of serotonergic hallucinogen-induced altered states of consciousness. Although the serotonergic hallucinogen psilocybin activates multiple serotonin (5-HT) receptors, recent evidence suggests that activation of 5-HT2A receptors may lead to the formation of visual hallucinations by increasing cortical excitability and altering visual-evoked cortical responses. To address this hypothesis, we assessed the effects of psilocybin (215 ?g/kg vs placebo) on both ? oscillations that regulate cortical excitability and early visual-evoked P1 and N170 potentials in healthy human subjects. To further disentangle the specific contributions of 5-HT2A receptors, subjects were additionally pretreated with the preferential 5-HT2A receptor antagonist ketanserin (50 mg vs placebo). We found that psilocybin strongly decreased prestimulus parieto-occipital ? power values, thus precluding a subsequent stimulus-induced ? power decrease. Furthermore, psilocybin strongly decreased N170 potentials associated with the appearance of visual perceptual alterations, including visual hallucinations. All of these effects were blocked by pretreatment with the 5-HT2A antagonist ketanserin, indicating that activation of 5-HT2A receptors by psilocybin profoundly modulates the neurophysiological and phenomenological indices of visual processing. Specifically, activation of 5-HT2A receptors may induce a processing mode in which stimulus-driven cortical excitation is overwhelmed by spontaneous neuronal excitation through the modulation of ? oscillations. Furthermore, the observed reduction of N170 visual-evoked potentials may be a key mechanism underlying 5-HT2A receptor-mediated visual hallucinations. This change in N170 potentials may be important not only for psilocybin-induced states but also for understanding acute hallucinatory states seen in psychiatric disorders, such as schizophrenia and Parkinson's disease. PMID:23785166

  11. A Steady-State Visual Evoked Potential Brain-Computer Interface System Evaluation as an In-Vehicle Warning Device

    NASA Astrophysics Data System (ADS)

    Riyahi, Pouria

    This thesis is part of current research at Center for Intelligence Systems Research (CISR) at The George Washington University for developing new in-vehicle warning systems via Brain-Computer Interfaces (BCIs). The purpose of conducting this research is to contribute to the current gap between BCI and in-vehicle safety studies. It is based on the premise that accurate and timely monitoring of human (driver) brain's signal to external stimuli could significantly aide in detection of driver's intentions and development of effective warning systems. The thesis starts with introducing the concept of BCI and its development history while it provides a literature review on the nature of brain signals. The current advancement and increasing demand for commercial and non-medical BCI products are described. In addition, the recent research attempts in transportation safety to study drivers' behavior or responses through brain signals are reviewed. The safety studies, which are focused on employing a reliable and practical BCI system as an in-vehicle assistive device, are also introduced. A major focus of this thesis research has been on the evaluation and development of the signal processing algorithms which can effectively filter and process brain signals when the human subject is subjected to Visual LED (Light Emitting Diodes) stimuli at different frequencies. The stimulated brain generates a voltage potential, referred to as Steady-State Visual Evoked Potential (SSVEP). Therefore, a newly modified analysis algorithm for detecting the brain visual signals is proposed. These algorithms are designed to reach a satisfactory accuracy rate without preliminary trainings, hence focusing on eliminating the need for lengthy training of human subjects. Another important concern is the ability of the algorithms to find correlation of brain signals with external visual stimuli in real-time. The developed analysis models are based on algorithms which are capable of generating results for real-time processing of BCI devices. All of these methods are evaluated through two sets of recorded brain signals which were recorded by g.TEC CO. as an external source and recorded brain signals during our car driving simulator experiments. The final discussion is about how the presence of an SSVEP based warning system could affect drivers' performances which is defined by their reaction distance and Time to Collision (TTC). Three different scenarios with and without warning LEDs were planned to measure the subjects' normal driving behavior and their performance while they use a warning system during their driving task. Finally, warning scenarios are divided into short and long warning periods without and with informing the subjects, respectively. The long warning period scenario attempts to determine the level of drivers' distraction or vigilance during driving. The good outcome of warning scenarios can bridge between vehicle safety studies and online BCI system design research. The preliminary results show some promise of the developed methods for in-vehicle safety systems. However, for any decisive conclusion that considers using a BCI system as a helpful in-vehicle assistive device requires far deeper scrutinizing.

  12. Cryptic vascular malformations involving the brainstem

    SciTech Connect

    Yeates, A.; Enzmann, D.

    1983-01-01

    Six patients with angiographically cryptic vascular malformations involving the brainstem were examined with computed tomography (CT). The clinical and CT findings of cryptic vascular malformations of the brainstem are described and distinguished from those of brainstem glioma and multiple sclerosis. Calcification within a brainstem lesion that displays relatively little mass effect and shows little contrast enhancement, particularly when associated with a long history of waxing and waning brainstem symptoms, should suggest a vascular malformation.

  13. External QX-314 inhibits evoked cranial primary afferent synaptic transmission independent of TRPV1.

    PubMed

    Hofmann, Mackenzie E; Largent-Milnes, Tally M; Fawley, Jessica A; Andresen, Michael C

    2014-12-01

    The cell-impermeant lidocaine derivative QX-314 blocks sodium channels via intracellular mechanisms. In somatosensory nociceptive neurons, open transient receptor potential vanilloid type 1 (TRPV1) receptors provide a transmembrane passageway for QX-314 to produce long-lasting analgesia. Many cranial primary afferents express TRPV1 at synapses on neurons in the nucleus of the solitary tract and caudal trigeminal nucleus (Vc). Here, we investigated whether QX-314 interrupts neurotransmission from primary afferents in rat brain-stem slices. Shocks to the solitary tract (ST) activated highly synchronous evoked excitatory postsynaptic currents (ST-EPSCs). Application of 300 ?M QX-314 increased the ST-EPSC latency from TRPV1+ ST afferents, but, surprisingly, it had similar actions at TRPV1- ST afferents. Continued exposure to QX-314 blocked evoked ST-EPSCs at both afferent types. Neither the time to onset of latency changes nor the time to ST-EPSC failure differed between responses for TRPV1+ and TRPV1- inputs. Likewise, the TRPV1 antagonist capsazepine failed to prevent the actions of QX-314. Whereas QX-314 blocked ST-evoked release, the frequency and amplitude of spontaneous EPSCs remained unaltered. In neurons exposed to QX-314, intracellular current injection evoked action potentials suggesting a presynaptic site of action. QX-314 acted similarly at Vc neurons to increase latency and block EPSCs evoked from trigeminal tract afferents. Our results demonstrate that QX-314 blocked nerve conduction in cranial primary afferents without interrupting the glutamate release mechanism or generation of postsynaptic action potentials. The TRPV1 independence suggests that QX-314 either acted extracellularly or more likely entered these axons through an undetermined pathway common to all cranial primary afferents. PMID:25185814

  14. Visual evoked potential evidence of albino-like chiasmal misrouting in a patient with Angelman syndrome with no ocular features of albinism.

    PubMed

    Thompson, D A; Kriss, A; Cottrell, S; Taylor, D

    1999-09-01

    An 8-month-old boy with global developmental delay, including visual and hearing inattention, was examined in the ophthalmic clinic. Monocular flash visual evoked potentials demonstrated a crossed asymmetry in scalp distribution, a feature considered to be pathognomic of albinism. Remarkably a foveal reflex was noted in each eye and this patient did not have nystagmus, iris transillumination, nor conspicuously pale fundi. The optic discs appeared normal. He was noted to have very fair skin and hair, with a small head and flat occiput. Cytogenetic studies demonstrated a microdeletion of the maternal chromosome 15q11-q13, and he was diagnosed with Angelman syndrome. PMID:10503922

  15. Variation and action potentials evoked by thermal stimuli accompany enhancement of ethylene emission in distant non-stimulated leaves of Vicia faba minor seedlings.

    PubMed

    Dziubinska, Halina; Filek, Maria; Koscielniak, Janusz; Trebacz, Kazimierz

    2003-10-01

    Electrical activity (action and variation potentials) and ethylene emission were measured in thermally stimulated Vicia faba minor seedlings. It was determined that variation potential with or without super-imposed action potentials was generated and propagated basipetally in response to scorching of the upper leaf. In stimulated plants the level of ethylene production measured in lower, non stimulated leaf was significantly higher than that in the control plants and the difference correlated with the amplitude of the electrical response. Neither variation nor action potential was recorded when ethylene was injected to the chamber covering the experimental leaf. The level of ethylene emission showed clear circadian rhythm when measured at photoperiod 16:8 (LD) or at constant light (LL). It is concluded that the sequence of ion fluxes registered as an electrical response of a plant to the thermal stimulus is a signal evoking an enhancement of ethylene emission. PMID:14610889

  16. Hearing disorders in brainstem lesions.

    PubMed

    Celesia, Gastone G

    2015-01-01

    Auditory processing can be disrupted by brainstem lesions. It is estimated that approximately 57% of brainstem lesions are associated with auditory disorders. However diseases of the brainstem usually involve many structures, producing a plethora of other neurologic deficits, often relegating "auditory symptoms in the background." Lesions below or within the cochlear nuclei result in ipsilateral auditory-processing abnormalities detected in routine testing; disorders rostral to the cochlear nuclei may result in bilateral abnormalities or may be silent. Lesions in the superior olivary complex and trapezoid body show a mixture of ipsilateral, contralateral, and bilateral abnormalities, whereas lesions of the lateral lemniscus, inferior colliculus, and medial geniculate body do not affect peripheral auditory processing and result in predominantly subtle contralateral abnormalities that may be missed by routine auditory testing. In these cases psychophysical methods developed for the evaluation of central auditory function should be employed (e.g., dichotic listening, interaural time perception, sound localization). The extensive connections of the auditory brainstem nuclei not only are responsible for binaural interaction but also assure redundancy in the system. This redundancy may explain why small brainstem lesions are sometimes clinically silent. Any disorder of the brainstem (e.g., neoplasms, vascular disorders, infections, trauma, demyelinating disorders, neurodegenerative diseases, malformations) that involves the auditory pathways and/or centers may produce hearing abnormalities. PMID:25726288

  17. Surgical approaches to brainstem cavernous malformations.

    PubMed

    Abla, Adib A; Turner, Jay D; Mitha, Alim P; Lekovic, Gregory; Spetzler, Robert F

    2010-09-01

    Brainstem cavernous malformations (CMs) are low-flow vascular lesions in eloquent locations. Their presentation is often marked with symptomatic hemorrhages that appear to occur more frequently than hemorrhage from supratentorial cavernomas. Brainstem CMs can be removed using 1 of the 5 standard skull-base approaches: retrosigmoid, suboccipital (with or without telovelar approach), supracerebellar infratentorial, orbitozygomatic, and far lateral. Patients being referred to a tertiary institution often have lesions that are aggressive with respect to bleeding rates. Nonetheless, the indications for surgery, in the authors' opinion, are the same for all lesions: those that are symptomatic, those that cause mass effect, or those that abut a pial surface. Patients often have relapsing and remitting courses of symptoms, with each hemorrhage causing a progressive and stepwise decline. Many patients experience new postoperative deficits, most of which are transient and resolve fully. Despite the risks associated with operating in this highly eloquent tissue, most patients have had favorable outcomes in the authors' experience. Surgical treatment of brainstem CMs protects patients from the potentially devastating effects of rehemorrhage, and the authors believe that the benefits of intervention outweigh the risks in patients with the appropriate indications. PMID:20809766

  18. Dopamine modulates attentional control of auditory perception: DARPP-32 (PPP1R1B) genotype effects on behavior and cortical evoked potentials.

    PubMed

    Li, Shu-Chen; Passow, Susanne; Nietfeld, Wilfried; Schröder, Julia; Bertram, Lars; Heekeren, Hauke R; Lindenberger, Ulman

    2013-07-01

    Using a specific variant of the dichotic listening paradigm, we studied the influence of dopamine on attentional modulation of auditory perception by assessing effects of allelic variation of a single-nucleotide polymorphism (SNP) rs907094 in the DARPP-32 gene (dopamine and adenosine 3', 5'-monophosphate-regulated phosphoprotein 32 kilodations; also known as PPP1R1B) on behavior and cortical evoked potentials. A frequent DARPP-32 haplotype that includes the A allele of this SNP is associated with higher mRNA expression of DARPP-32 protein isoforms, striatal dopamine receptor function, and frontal-striatal connectivity. As we hypothesized, behaviorally the A homozygotes were more flexible in selectively attending to auditory inputs than any G carriers. Moreover, this genotype also affected auditory evoked cortical potentials that reflect early sensory and late attentional processes. Specifically, analyses of event-related potentials (ERPs) revealed that amplitudes of an early component of sensory selection (N1) and a late component (N450) reflecting attentional deployment for conflict resolution were larger in A homozygotes than in any G carriers. Taken together, our data lend support for dopamine's role in modulating auditory attention both during the early sensory selection and late conflict resolution stages. PMID:23639477

  19. Dose-response characteristics of methylphenidate on locomotor behavior and on sensory evoked potentials recorded from the VTA, NAc, and PFC in freely behaving rats

    PubMed Central

    Yang, Pamela B; Swann, Alan C; Dafny, Nachum

    2006-01-01

    Background Methylphenidate (MPD) is a psychostimulant commonly prescribed for attention deficit/hyperactivity disorder. The mode of action of the brain circuitry responsible for initiating the animals' behavior in response to psychostimulants is not well understood. There is some evidence that psychostimulants activate the ventral tegmental area (VTA), nucleus accumbens (NAc), and prefrontal cortex (PFC). Methods The present study was designed to investigate the acute dose-response of MPD (0.6, 2.5, and 10.0 mg/kg) on locomotor behavior and sensory evoked potentials recorded from the VTA, NAc, and PFC in freely behaving rats previously implanted with permanent electrodes. For locomotor behavior, adult male Wistar-Kyoto (WKY; n = 39) rats were given saline on experimental day 1 and either saline or an acute injection of MPD (0.6, 2.5, or 10.0 mg/kg, i.p.) on experimental day 2. Locomotor activity was recorded for 2-h post injection on both days using an automated, computerized activity monitoring system. Electrophysiological recordings were also performed in the adult male WKY rats (n = 10). Five to seven days after the rats had recovered from the implantation of electrodes, each rat was placed in a sound-insulated, electrophysiological test chamber where its sensory evoked field potentials were recorded before and after saline and 0.6, 2.5, and 10.0 mg/kg MPD injection. Time interval between injections was 90 min. Results Results showed an increase in locomotion with dose-response characteristics, while a dose-response decrease in amplitude of the components of sensory evoked field responses of the VTA, NAc, and PFC neurons. For example, the P3 component of the sensory evoked field response of the VTA decreased by 19.8% ± 7.4% from baseline after treatment of 0.6 mg/kg MPD, 37.8% ± 5.9% after 2.5 mg/kg MPD, and 56.5% ± 3.9% after 10 mg/kg MPD. Greater attenuation from baseline was observed in the NAc and PFC. Differences in the intensity of MPD-induced attenuation were also found among these brain areas. Conclusion These results suggest that an acute treatment of MPD produces electrophysiologically detectable alterations at the neuronal level, as well as observable, behavioral responses. The present study is the first to investigate the acute dose-response effects of MPD on behavior in terms of locomotor activity and in the brain involving the sensory inputs of VTA, NAc, and PFC neurons in intact, non-anesthetized, freely behaving rats previously implanted with permanent electrodes. PMID:16417623

  20. Sensory deficits of a nerve root lesion can be objectively documented by somatosensory evoked potentials elicited by painful infrared laser stimulations: a case study.

    PubMed Central

    Lorenz, J; Hansen, H C; Kunze, K; Bromm, B

    1996-01-01

    Somatosensory evoked potentials (SEPs) in response to painful laser stimuli were measured in a patient with a unilateral sensory deficit due to radiculopathy at cervical levels C7 and C8. Laser evoked potentials (LEPs) were compared with SEPs using standard electrical stimulation of median and ulnar nerves at the wrist and mechanical stimulation of the fingertips by means of a mechanical stimulator. Early and late ulnar and median nerve SEPs were normal. Mechanical stimulation resulted in w shaped early SEPs from all five fingertips with some degree of abnormality at the fourth and fifth digits of the affected hand. Late LEPs were completely absent for stimulations at affected dermatomes and normal in the unaffected control dermatomes. The border between skin areas with normal or absent LEPs was very sharp and fitted the dermatomes of intact C6 and damaged C7 and C8 nerve roots. It is suggested that pain dermatomes are narrower than tactile dermatomes because thin fibres of the nociceptive system, activated by laser stimuli, probably do not overlap between adjacent spinal segments to the same extent as thick fibres of the mechanoreceptive system, activated by standard electrical or mechanical stimulation. Images PMID:8676136

  1. Advanced glycation end products potentiate citrated plasma-evoked oxidative and inflammatory reactions in endothelial cells by up-regulating protease-activated receptor-1 expression.

    PubMed

    Ishibashi, Yuji; Matsui, Takanori; Ueda, Seiji; Fukami, Kei; Yamagishi, Sho-ichi

    2014-01-01

    Advanced glycation end products (AGEs) and receptor RAGE interaction contribute to endothelial cell damage in diabetes. Several thrombogenic abnormalities are also involved in diabetic vascular complications. However, the pathological role of thrombin and protease-activated receptor-1 (PAR-1) system in AGE-induced endothelial cell (EC) damage remains unclear. In this study, we investigated the effects of rivaroxaban, an inhibitor of factor Xa on 3% citrated human plasma-evoked reactive oxygen species (ROS) generation and RAGE, monocyte chemoattractant protein-1 (MCP-1) and intercellular adhesion molecule-1 (ICAM-1) gene expression in AGE-exposed ECs. We further examined whether FR171113, an inhibitor of PAR-1 blocked the plasma-induced EC damage and if AGEs increased PAR-1 expression in ECs. Human citrated plasma stimulated ROS generation and RAGE, MCP-1 and ICAM-1 expression in ECs, all of which were potentiated by the treatment with AGEs. Rivaroxaban or FR171113 significantly inhibited these derangements in plasma- or plasma plus AGE-exposed ECs. Moreover, AGEs significantly increased the PAR-1 levels in ECs. The present study suggests that citrated plasma could induce oxidative and inflammatory reactions in ECs via the activation of thrombin-PAR-1 system and that AGEs could potentiate the plasma-evoked EC damages via up-regulation of PAR-1. Blockade of the crosstalk between AGE-RAGE axis and coagulation system by rivaroxaban might be a novel therapeutic target for thromboembolic disorders in diabetes. PMID:24624928

  2. Association between surgical steps and intraoperative auditory brainstem response and electrocochleography waveforms during hearing preservation vestibular schwannoma surgery.

    PubMed

    Gouveris, Haralampos; Mann, Wolf

    2009-02-01

    Intraoperative monitoring of the auditory pathway by means of either electrocochleography or auditory brainstem response audiometry is valuable during hearing preservation vestibular schwannoma (VS) surgery. A more than 75% intraoperative reduction of the amplitude of these evoked auditory potentials was thought to be related with clear hearing compromise of hearing. We identified 22 patients who satisfied this intraoperative criterion in a cohort of 86 consecutive patients who had attempted hearing preservation VS surgery. The surgical step that temporally coincided with the above event was considered to be the most critical step for hearing monitoring during this kind of surgery. Most frequently, drilling of the internal auditory canal and direct tumor resection were associated with the aforementioned changes, but also drilling of the cortical temporal bone at the very beginning of surgery or the opening of the dura could be implicated. This profound intraoperative amplitude decrease was associated with a profound postoperative hearing impairment in 84% of the cases. PMID:18553092

  3. 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.

  4. Loss and Spontaneous Recovery of Forelimb Evoked Potentials in both the Adult Rat Cuneate Nucleus and Somatosensory Cortex following Contusive Cervical Spinal Cord Injury

    PubMed Central

    Onifer, Stephen M.; Nunn, Christine D.; Decker, Julie A.; Payne, Beth N.; Wagoner, Michelle R.; Puckett, Aaron H.; Massey, James M.; Armstrong, James; Kaddumi, Ezidin G.; Fentress, Kimberly G.; Wells, Michael J.; West, Robert M.; Calloway, Charles C.; Schnell, Jeffrey T.; Whitaker, Christopher M.; Burke, Darlene A.; Hubscher, Charles H.

    2007-01-01

    Varying degrees of neurologic function spontaneously recovers in humans and animals during the days and months after spinal cord injury (SCI). For example, abolished upper limb somatosensory potentials (SSEPS) and cutaneous sensations can recover in persons post-contusive cervical SCI. To maximize recovery and the development/evaluation of repair strategies, a better understanding of the anatomical locations and physiological processes underlying spontaneous recovery after SCI is needed. As an initial step, the present study examined whether recovery of upper limb SSEPs after contusive cervical SCI was due to the integrity of some spared dorsal column primary afferents that terminate within the cuneate nucleus and not one of several alternate routes. C5-C6 contusions were performed on male adult rats. Electrophysiological techniques were used in the same rat to determine forelimb evoked neuronal responses in both cortex (SSEPS) and the cuneate nucleus (terminal extracellular recordings). SSEPs were not evoked 2 days post-SCI but were found at 7 days and beyond, with an observed change in latencies between 7 and 14 days (suggestive of spared axon remyelination). Forelimb evoked activity in the cuneate nucleus at 15 but not 3 days post-injury occurred despite dorsal column damage throughout the cervical injury (as seen histologically). Neuroanatomical tracing (using 1% unconjugated cholera toxin B subunit) confirmed that upper limb primary afferent terminals remained within the cuneate nuclei. Taken together, these results indicate that neural transmission between dorsal column primary afferents and cuneate nuclei neurons is likely involved in the recovery of upper limb SSEPs after contusive cervical SCI. PMID:17678895

  5. Auditory brainstem responses to clicks and tone bursts in C57 BL/6J mice.

    PubMed

    Scimemi, P; Santarelli, R; Selmo, A; Mammano, F

    2014-08-01

    In auditory research, hearing function of mouse mutants is assessed in vivo by evoked potential recording. Evaluation of the response parameters should be performed with reference to the evoked responses recorded from wild-type mice. This study reports normative data calculated on auditory brainstem responses (ABRs) obtained from 20 wild-type C57 BL/6J mice at a postnatal age between 21 and 45 days. Acoustic stimuli consisted tone bursts at 8, 14, 20, 26, 32 kHz, and clicks. Each stimulus was delivered in free field at stimulation intensity starting from a maximum of 100 dB peak equivalent SPL (dB peSPL) at decreasing steps of 10 dB with a repetition rate of 13/sec. Evoked responses were recorded by needle electrodes inserted subcutaneously. At high intensity stimulation, five response waveforms, each consisting of a positive peak and a subsequent negative valley, were identified within 7 msec, and were labelled with sequential capital Roman numerals from I to V. Peak IV was the most robust and stable at low intensities for both tone burst and click stimuli, and was therefore utilized to estimate hearing thresholds. Both latencies and amplitudes of ABR peaks showed good reproducibility with acceptable standard deviations. Mean wave IV thresholds measured across all animals ranged from a maximum of 23 dB peSPL for clicks to a minimum of 7 dB peSPL for 20 kHz-tone burst stimuli. Statistical analysis of the distribution of latencies and amplitudes of peaks from I to V performed for each stimulus type yielded a normative data set which was utilised to obtain the most consistent fitting-curve model. This could serve as a reference for further studies on murine models of hearing loss. PMID:25210221

  6. [Changes in evoked potentials during systematic exposure to a series of similar signals with variable intersignal intervals].

    PubMed

    Varga, M E; Tveritskaia, I N

    1976-01-01

    Series of clicks, standard by the number of stimuli and greatly varying by the length of interstimuli intervals in each series, were systematically presented to dogs without reinforcement. Evoked potentiale (EP) in the cortical auditory zone were recorded. It has been found that a typical U-shaped distribution of amplitude values of averaged EP is elaborated in the series in the course of repeated presentations; a maximal amplitude is observed in response to the first and last clicks, and a minimal, in the middle of the series. Such a regularity was previously found for the action of standard series with a constant interstimuli interval. It is assumed that an estimation may take place in the dog CNS of the number of signals used in a series, whose mechanism is not necessarily based on the time factor. The ability to estimate the number of signals in the series may be regarded as an elementary model of counting in the dogs' CNS. PMID:1274469

  7. [Comparative studies of hearing in children by recording reflex reactions and long-latency auditory evoked potentials].

    PubMed

    Ryndina, A M; Grachev, K V; Slesarenko, N P; Utianova, T A; Tsvyleva, I D

    1990-01-01

    Hearing thresholds at speech frequencies in children with neurosensory hypoacusis were measured by three methods: orientation reflex (OR), wink reflex (WR) and brain acoustic evoked responses (BERA). Hearing thresholds measured by recording OR and WR were compared in 115 children (232 comparisons) and were found to coincide in about 92% of cases. Hearing thresholds at speech frequencies were measured by recording OR, WR and BERA in 55 children (103 comparisons) and were found to coincide in about 70% of cases. The discrepancy in the thresholds, especially when measured by means of BERA and WR, was seen mainly in the children who suffered from neurosensory hypoacusis and other CNS disorders (oligophrenia, residual manifestations of birth cerebral palsy with mental retardation, symptoms of sensory alalia). It is concluded that the method of recording WR allows a sufficiently accurate measurement of hearing thresholds. However, a comprehensive examination should be performed using all three methods to reveal concomitant diseases. PMID:2360301

  8. The importance of cochlear processing for the formation of auditory brainstem and frequency following responses.

    PubMed

    Dau, Torsten

    2003-02-01

    A model for the generation of auditory brainstem responses (ABR) and frequency following responses (FFRs) is presented. The model is based on the concept introduced by Goldstein and Kiang [J. Acoust. Soc. Am. 30, 107-114 (1958)] that evoked potentials recorded at remote electrodes can theoretically be given by convolution of an elementary unit waveform (unitary response) with the instantaneous discharge rate function for the corresponding unit. In the present study, the nonlinear computational auditory-nerve model recently developed by Heinz et al. [ARLO 2(3), 91-96 (2001)] was used to calculate the instantaneous discharge rate ri(t) for fibers i in the frequency range from 0.1 and 10 kHz. The summed activity across frequency was convolved with a unitary response which is assumed to reflect contributions from different cell populations within the auditory brainstem, recorded at a given pair of electrodes on the scalp. Predicted potential patterns are compared with experimental data for a number of stimulus and level conditions. Clicks, chirps as defined in Dau et al. [J. Acoust. Soc. Am. 107, 1530-1540 (2000)], long-duration stimuli comprising the chirp, as well as tones and slowly varying tonal sweeps were considered. The results demonstrate the importance of considering the effects of the basilar-membrane traveling wave and auditory-nerve processing for the formation of ABR and FFR. Specifically, the results support the hypothesis that the FFR to low-frequency tones represents synchronized activity mainly stemming from mid- and high-frequency units at more basal sites, and not from units tuned to frequencies around the signal frequency. PMID:12597187

  9. Rapid Estrogenic Effects on TMJ-responsive Brainstem Neurons

    PubMed Central

    Tashiro, A.; Okamoto, K.; Bereiter, D.A.

    2012-01-01

    Estrogen status is a risk factor for temporomandibular muscle and joint disorders (TMJD) and other craniofacial pain conditions. The basis for estrogen modulation of pain is poorly understood and has often been attributed to long-term genomic effects. However, estrogens also act rapidly through membrane-initiated mechanisms to alter neural activity. To assess if estrogens act rapidly to affect TMJ-responsive neurons, we applied 17?-estradiol (E2) directly at the spinomedullary (Vc/C1-2) region, the initial brainstem site for synaptic integration of TMJ sensory signals, while recording single neuron activity. In ovariectomized female rats, E2 rapidly (within 10 minutes) and reversibly reduced TMJ-evoked neural activity at the Vc/C1-2 region. The effect was estrogen receptor (ER) subtype-specific, since ER? agonists inhibited, while an ER? agonist enhanced, evoked activity. A membrane-mediated mechanism was indicated, since the membrane-impermeable analogue, E2-BSA, mimicked the inhibitory effect of E2 and was prevented by an ER antagonist. This study demonstrated that E2 acted rapidly, through membrane-mediated pathways, and locally at the Vc/C1-2 region, to modulate sensory signals from the TMJ region. These results were consistent with the hypothesis that estrogens can act rapidly at the level of the trigeminal brainstem complex to influence sensory integration of TMJ-related information. PMID:22058119

  10. Evidence for separate processing in the human brainstem of interaural intensity and temporal disparities for sound lateralization.

    PubMed

    Pratt, H; Polyakov, A; Kontorovich, L

    1997-06-01

    Sound lateralization can be induced by interaural intensity disparities (IIDs) or by interaural temporal disparities (ITDs). The purpose of this study was to indicate whether IIDs and ITDs are processed by the same central units that detect interaural disparity in timing of afferent activity. If sound lateralization to intensity and time cues was determined by the same afferent latency disparity detectors in the brainstem, lateralization would be the same, regardless of whether latency disparity was induced by IIDs or ITDs. Moreover, the disparity detectors, and thus their dipole equivalents, would be the same for equal lateralizations, whether induced by IIDs or ITDs. Auditory brainstem evoked potentials (ABEPs) were recorded in response to monaural and binaural clicks, with a variety of IIDs and ITDs. Peak II (proximal auditory nerve activity), peak III (input to the superior olivary complex), and binaural interaction components (BICs) BeI and BeII (binaurally activated upper pons) were identified and their latencies measured. The psychophysical lateralization of the clicks (in cm from vertex) was also measured in response to the same binaural stimuli. The correlations between interaural afferent latency disparities (difference in corresponding peak latencies originating in each ear) and psychophysical click lateralization were calculated. Similarly, the correlations with click lateralization of the BICs equivalent dipole latency as well as orientation change (relative to symmetrical clicks) were determined. A strong correlation with lateralization was found for peaks II and III latency disparities, with steeper slopes for IIDs than for ITDs. Moreover, binaural activity across the same lateralizations differed between IIDs and ITDs. These results, therefore, indicate that interaural time and intensity cues are processed by separate systems in the brainstem, both at the afferent convergence level and after interaural disparities are determined. PMID:9213116

  11. Short latency visual evoked potentials in occupational exposure to organic solvents * 1 * Supported by the Israeli Ministry of Labour and Social Affairs, Committee for Preventative Action in Work Safety and Health

    Microsoft Academic Search

    H Pratt; N Karim; N Bleich; N Mittelman

    2000-01-01

    Objectives. Short latency visual evoked potentials (SVEP), in response to high-intensity flashes from light emitting diodes (LED), were used to detect subclinical effects along the visual pathway in four groups of subjects with different levels of exposure to gasoline, all within legally acceptable limits. Methods. Potentials and exposure levels were obtained from 31 subjects with different occupational exposure levels to

  12. Functional integrity of benzodiazepine receptors of the geniculo-striate visual pathways in Creutzfeldt-Jakob disease. A pharmacological evoked potential study.

    PubMed

    Aguglia, U; Oliveri, R L; Gambardella, A; Quattrone, A

    1993-01-01

    We evaluated the effects of flumazenil (FMZ), a high-affinity benzodiazepine receptor antagonist, on flash-evoked visual potentials (FEPs) in a patient with Creutzfeldt-Jacob disease (CJD). FEPs were recorded in three different consecutive sessions: (1) basal condition, without any pharmacological treatment; (2) 3.5 min after i.v. administration of 5 mg FMZ; (3) 1 min after i.v. administration of 10 mg diazepam (DZP). FMZ provoked a marked increase in the amplitude as well as evident shortening of the latency of early FEP components. DZP reversed these effects. These results are in agreement with our previous findings of anatomical and functional integrity of the geniculo-striate pathways in human CJD and demonstrate functional integrity of benzodiazepine receptors in this visual system in CJD. PMID:8380846

  13. Effect of sensory inputs on the motor evoked potentials in the wrist flexor muscle during the robotic passive stepping in humans.

    PubMed

    Kitamura, Taku; Nakajima, Tsuyoshi; Yamamoto, Shin-Ichiro; Nakazawa, Kimitaka

    2012-01-01

    The purpose of this study was to reveal whether the stepping-related afferent feedback modulates the motor evoked potentials (MEPs) in the wrist flexor muscle in humans. MEPs generated in flexor carpi radialis muscle (FCR) by transcranial magnetic stimulation (TMS) were recorded during robotic-assisted passive stepping and standing conditions. TMS were applied at fifteen scalp sites (3 × 5 cm grid in anterior-posterior direction and medial-lateral direction, respectively) centered on the "hot spot" which was defined as an optimal site for eliciting the MEP in FCR during passive standing task, The MEP amplitudes were measured for each stimulus sites, and then compared between different conditions. During passive stepping, the MEP amplitudes in FCR muscle were significantly increased in six adjacent stimulus sites of the hot spot, This result suggests that stepping-related afferent feedback induces expansion of excitatory area in motor cortex for FCR muscle. PMID:23366771

  14. A role for motor and somatosensory evoked potentials during anterior cervical discectomy and fusion for patients without myelopathy: Analysis of 57 consecutive cases

    PubMed Central

    Xu, Risheng; Ritzl, Eva K.; Sait, Mohammed; Sciubba, Daniel M.; Wolinsky, Jean-Paul; Witham, Timothy F.; Gokaslan, Ziya L.; Bydon, Ali

    2011-01-01

    Background: Although the usage of combined motor and sensory intraoperative monitoring has been shown to improve the surgical outcome of patients with cervical myelopathy, the role of transcranial electric motor evoked potentials (tceMEP) used in conjunction with somatosensory evoked potentials (SSEP) in patients presenting with radiculopathy but without myelopathy has been less clear. Methods: We retrospectively reviewed all patients (n = 57) with radiculopathy but without myelopathy, undergoing anterior cervical decompression and fusion at a single institution over the past 3 years, who had intraoperative monitoring with both tceMEPs and SSEPs. Results: Fifty-seven (100%) patients presented with radiculopathy, 53 (93.0%) with mechanical neck pain, 35 (61.4%) with motor dysfunction, and 29 (50.9%) with sensory deficits. Intraoperatively, 3 (5.3%) patients experienced decreases in SSEP signal amplitudes and 4 (6.9%) had tceMEP signal changes. There were three instances where a change in neuromonitoring signal required intraoperative alteration of the surgical procedure: these were deemed clinically significant events/true positives. SSEP monitoring showed two false positives and two false negatives, whereas tceMEP monitoring only had one false positive and no false negatives. Thus, tceMEP monitoring exhibited higher sensitivity (33.3% vs. 100%), specificity (95.6% vs. 98.1%), positive predictive value (33.3% vs. 75.0%), negative predictive value (97.7% vs. 100%), and efficiency (91.7% vs. 98.2%) compared to SSEP monitoring alone. Conclusions: Here, we present a retrospective series of 57 patients where tceMEP/SSEP monitoring likely prevented irreversible neurologic damage. Though further prospective studies are needed, there may be a role for combined tceMEP/SSEP monitoring for patients undergoing anterior cervical decompression without myelopathy. PMID:22059128

  15. Study to evaluate the encephalotropic potency of a hemodialysate. Controlled study using electro-retinography and visual evoked potentials under hypoxic conditions in human volunteers (preliminary communication).

    PubMed

    Schaffler, K; Wauschkuhn, C H; Häuser, B

    1991-07-01

    Twelve healthy young males volunteered in this pilot-study to test the encephalotropic potency of a deproteinized hemodialysate of calf blood (Actovegin). This compound contains peptides, oligosaccharides and nucleinic acid derivatives, which are supposed to improve transport of glucose and oxygen into cells. The study is based on a placebo-controlled, partially double-blind, 3-way crossover design. The subjects received single administrations of the hemodialysate as injection (10 ml, 400 mg), as infusion (500 ml, 4 g) and a placebo injection (saline) in randomized sequence. Drug effects on visual evoked potentials (VEP) and electro-retinography (ERG) were tested--in the context of a hypoxia based model of dementia (10.5% O2 inspiratory)--1, 2, and 4 h post administration. The main target variables were the amplitudes of the VEP-P2-component and of the ERG-b-wave. The hemodialysate--as an encephalotropic drug--was expected to counteract the hypoxia-induced reduction of both amplitudes. On a descriptive/exploratory level the restitution of the (hypoxia-suppressed) target variables was found. The combined application of visual evoked potentials (VEP) and of electroretinography (ERG) was able to consistently reveal central and peripheral sites of hypoxia-antagonistic action of the drug in study, which might not be restricted solely to neuronal structures, but seems to be extended to glial structures too. The predominant effects form a pattern of clinically relevant changes, which should be confirmed in a larger number of subjects. The preferable form of administration--featuring positive effects in hypoxia antagonism--seems to be the infusion with its higher dosage.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:1772457

  16. Functional development of the vagal and glossopharyngeal nerve-related nuclei in the embryonic rat brainstem: optical mapping with a voltage-sensitive dye

    Microsoft Academic Search

    Y. Momose-Sato; T. Nakamori; K. Sato

    2011-01-01

    We investigated functional organization of the vagus nerve (N. X)- and glossopharyngeal nerve (N. IX)-related nuclei in the embryonic rat brainstem and compared their development and spatial distribution patterns, using multiple-site optical recording with a fast voltage-sensitive dye, NK2761. Intact brainstem preparations with N. X and N. IX attached were dissected from E13-E16 rat embryos, and electrical responses evoked by

  17. Brainstem morphological changes in Alzheimer's disease.

    PubMed

    Lee, Ji Han; Ryan, John; Andreescu, Carmen; Aizenstein, Howard; Lim, Hyun Kook

    2015-05-01

    As brainstem nuclei are interconnected with several cortical structures and regulate several autonomic, cognitive, and behavioral functions, it might be important to place the brainstem within an important pathologic core in the progression of Alzheimer's disease (AD). Although there have been several postmortem studies reporting neuropathological alterations of the brainstem in AD, there has been no in-vivo structural neuroimaging study of the brainstem in the patients with AD. The aim of this study was to investigate differences in the brainstem volume and shape between patients with AD and elderly normal controls. Fifty AD patients (the Clinical Dementia Rating Scale?1) and 50 normal controls were recruited, and the brainstem volumes and deformations were compared between the AD and the controls. Patients with AD showed significant total volume [(mean±SD) 21007±1640?mm] reduction in the brainstem compared with the controls [(mean±SD) 22530±1750?mm] (P<0.001). In addition, AD patients showed significant brainstem deformations in the upper posterior brainstem corresponding to the midbrain compared with the healthy individuals (false discovery rate corrected P<0.05). This study is the first to explore brainstem volume change and deformations in AD. These structural changes in the midbrain areas might be at the core of the underlying neurobiological mechanisms of brainstem dysfunction with relevance to their various cognitive and behavioral symptoms such as memory impairment, sleep, and emotional disturbance in AD. However, further longitudinal studies might be needed to confirm these findings. PMID:25830491

  18. Ocular vestibular-evoked myogenic potentials (oVEMP) to skull taps in normal and dehiscent ears: mechanisms and markers of superior canal dehiscence.

    PubMed

    Taylor, Rachael L; Blaivie, Catherine; Bom, Andreas P; Holmeslet, Berit; Pansell, Tony; Brantberg, Krister; Welgampola, Miriam S

    2014-04-01

    The site of stimulus delivery modulates the waveforms of cervical- and ocular vestibular-evoked myogenic potentials (cVEMP and oVEMP) to skull taps in healthy controls. We examine the influence of stimulus location on the oVEMP waveforms of 18 patients (24 ears) with superior canal dehiscence (SCD) and compare these with the results of 16 healthy control subjects (32 ears). oVEMPs were recorded in response to taps delivered with a triggered tendon-hammer and a hand-held minishaker at three midline locations; the hairline (Fz), vertex (Cz) and occiput (Oz). In controls, Fz stimulation evoked a consistent oVEMP waveform with a negative peak (n1) at 9.5 ± 0.5 ms. In SCD, stimulation at Fz produced large oVEMP waveforms with delayed n1 peaks (tendon-hammer = 13.2 ± 1.0 ms and minitap = 11.5 ± 1.1 ms). Vertex taps produced diverse low-amplitude waveforms in controls with n1 peaks at 15.5 ± 1.2 and 13.2 ± 1.3 ms for tendon-hammer taps and minitaps, respectively; in SCD, they produced large amplitude oVEMP waveforms with n1 peaks at 12.9 ± 0.8 ms (tendon-hammer) and 12.1 ± 0.5 ms (minitap). Occiput stimulation evoked oVEMPs with similar n1 latencies in both groups (tendon-hammer = 11.3 ± 1.3 and 10.7 ± 0.8; minitap = 10.3 ± 0.9 and 11.1 ± 0.4 for control and SCD ears, respectively). Compared to reflex amplitudes, n1 peak latencies to Fz taps provided clearer separation between SCD and control ears. The distinctly different effects of Fz and vertex taps on the oVEMP waveforms may represent an additional non-osseous mechanism of stimulus transmission in SCD. For skull taps at Fz, a prolonged n1 latency is an indicator of SCD. PMID:24463425

  19. Generating synchrony from the asynchronous: compensation for cochlear traveling wave delays by the dendrites of individual brainstem neurons

    PubMed Central

    McGinley, Matthew J.; Liberman, M. Charles; Bal, Ramazan; Oertel, Donata

    2012-01-01

    Broadband transient sounds, such as clicks and consonants, activate a traveling wave in the cochlea. This wave evokes firing in auditory nerve fibers that are tuned to high frequencies several milliseconds earlier than in fibers tuned to low frequencies. Despite this substantial traveling wave delay, octopus cells in the brainstem receive broadband input and respond to clicks with submillisecond temporal precision. The dendrites of octopus cells lie perpendicular to the tonotopically organized array of auditory nerve fibers, placing the earliest arriving inputs most distally and the latest arriving closest to the soma. Here, we test the hypothesis that the topographic arrangement of synaptic inputs on dendrites of octopus cells allows octopus cells to compensate the traveling wave delay. We show that in mice the full cochlear traveling wave delay is 1.6 ms. Because the dendrites of each octopus cell spread across about one third of the tonotopic axis, a click evokes a soma directed sweep of synaptic input lasting 0.5 ms in individual octopus cells. Morphologically and biophysically realistic, computational models of octopus cells show that soma-directed sweeps with durations matching in vivo measurements result in the largest and sharpest somatic excitatory postsynaptic potentials (EPSPs). A low input resistance and activation of a low-voltage-activated potassium conductance that are characteristic of octopus cells are important determinants of sweep sensitivity. We conclude that octopus cells have dendritic morphologies and biophysics tailored to accomplish the precise encoding of broadband transient sounds. PMID:22764237

  20. Sound production evoked by electrical stimulation of the forebrain in the oyster toadfish

    Microsoft Academic Search

    M. L. Fine; M. A. Perini

    1994-01-01

    In mammals, birds and amphibians the neural pathways controlling sound production descend from higher centers in the forebrain, whereas in fishes only brainstem and spinal centers have been explicitly implicated in sound production. We now report that electrical stimulation of the forebrain of the oyster toadfish (Opsanus tau) readily evokes both the agonistic grunt and the courtship boatwhistle. Boatwhistles are