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Sample records for action potential evoked

  1. Action of hallucinogens on raphe-evoked dorsal root potentials (DRPs) in the cat.

    Science.gov (United States)

    Larson, A A; Anderson, E G

    1986-02-01

    The dorsal root potential (DRP) evoked by stimulation of the inferior central nucleus (ICN) of the cat is affected by administration of a variety of hallucinogenic agents. It has been previously shown that a single low dose of LSD is unique in that it potentiates this DRP, while injections of 5-methoxy-N,N- dimethyltryptamine (5-MeODMT), ketamine or phencyclidine (PCP) inhibit its production. Tolerance develops to the facilitatory effect of low doses of LSD on the DRP, but not to the inhibitory action of 5-MeODMT. Repeated injections of ketamine every 30 minutes also fail to produce tachyphylaxis to the inhibitory effect of this dissociative anesthetic. The raphe-evoked DRP is a long latency potential that is inhibited by a wide variety of putative serotonin antagonists and has therefore been traditionally thought to be mediated by serotonin. However, in light of the inability of either tryptophan or fluoxetine to potentiate this DRP, and the resistance of this DRP to blockade by parachlorophenylalanine, reserpine or intrathecally administered 5,7-dihydroxytryptamine, it appears that this potential may in fact be mediated, at least in part, by a non-serotonergic transmitter. PMID:3952125

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

    Directory of Open Access Journals (Sweden)

    Jason Robert Potas

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

  3. Motor evoked potential polyphasia

    OpenAIRE

    Chowdhury, Fahmida A.; Pawley, Adam D.; Ceronie, Bryan; Nashef, Lina; Robert D C Elwes; 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 produ...

  4. International Evoked Potentials Symposium

    CERN Document Server

    1980-01-01

    The past decade has seen great progress in the measurement of evoked potentials in man; a steady increase in our understanding of their charac­ teristics, their origins and their usefulness; and a growing application in the field of clinical diagnosis. The topic is a truly multidisciplinary one. Important research contributions have been made by workers of many different backgrounds and clinical applications span the specialities. This book represents a revised and updated version of the work originally presented at the international evoked potential symposium held in Nottingham 4-6 1978. The Nottingham Symposium provided a forum for a state-of-the-art discussion amongst workers from many different disciplines and from many different countries. For each major topic in the field an expert review set the scene for discussion of current research presentations. This format is retained in the book: the chapters in Part A provide the context in which the research presented in Part B is set. The task of selecting m...

  5. Action potential-evoked calcium release is impaired in single skeletal muscle fibers from heart failure patients.

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    Marino DiFranco

    Full Text Available 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.

  6. Potassium conductances mediate bidirectional state-dependent modulation of action potential evoked dendritic calcium signals in dentate gyrus granule cells

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    János Brunner

    2014-03-01

    Full Text Available Backpropagating action potentials (bAPs and local calcium signals that they trigger are fundamental for dendritic functions. Here we addressed the question what extent the changes of local dendritic membrane properties can contribute to the shaping of the coupling between dendritic action potentials and the local calcium responses. Using a combination of in vitro electrophysiological and confocal imaging techniques we found that activation of dendritic GIRK channels via mGlu2 or GABAB receptors enhanced the bAP¬-triggered calcium signals in the dendrites of dentate gyrus granule cells (GCs. The enhancement of calcium signals was significant only in those dendritic regions, where these receptors are predominantly expressed. Similarly to GIRK channel activation, somatic hyperpolarization by DC current injection (from -64 mV to -77 mV, significantly increased bAP-associated calcium signals in the proximal dendrites. The hyperpolarization was associated with a decrease in the input resistance due to the rectification of the membrane potential of GCs. The effect of hyperpolarization on the calcium signals was maintained when T-type calcium currents were blocked but it decreased when GIRK channels were inhibited. Simultaneous dual somato-dendritic recordings from GCs showed that somatic hyperpolarization accelerated the repolarization phase of dendritic bAP in the proximal region whereas the rising phase and peak amplitude was not affected. We hypothesize that the larger driving force for calcium ions during the faster repolarization can contribute to the increasing in calcium signals. Employment of previously recorded dendritic bAP waveforms from hyperpolarized membrane potential as voltage command evoked larger calcium currents in nucleated patches compared to bAP waveform from the same recording at depolarized membrane potential. Furthermore, addition of native, high-voltage activated, inactivating potassium conductance by somatic dynamic clamp

  7. Assessing the Electrode-Neuron Interface with the Electrically Evoked Compound Action Potential, Electrode Position, and Behavioral Thresholds.

    Science.gov (United States)

    DeVries, Lindsay; Scheperle, Rachel; Bierer, Julie Arenberg

    2016-06-01

    Variability in speech perception scores among cochlear implant listeners may largely reflect the variable efficacy of implant electrodes to convey stimulus information to the auditory nerve. In the present study, three metrics were applied to assess the quality of the electrode-neuron interface of individual cochlear implant channels: the electrically evoked compound action potential (ECAP), the estimation of electrode position using computerized tomography (CT), and behavioral thresholds using focused stimulation. The primary motivation of this approach is to evaluate the ECAP as a site-specific measure of the electrode-neuron interface in the context of two peripheral factors that likely contribute to degraded perception: large electrode-to-modiolus distance and reduced neural density. Ten unilaterally implanted adults with Advanced Bionics HiRes90k devices participated. ECAPs were elicited with monopolar stimulation within a forward-masking paradigm to construct channel interaction functions (CIF), behavioral thresholds were obtained with quadrupolar (sQP) stimulation, and data from imaging provided estimates of electrode-to-modiolus distance and scalar location (scala tympani (ST), intermediate, or scala vestibuli (SV)) for each electrode. The width of the ECAP CIF was positively correlated with electrode-to-modiolus distance; both of these measures were also influenced by scalar position. The ECAP peak amplitude was negatively correlated with behavioral thresholds. Moreover, subjects with low behavioral thresholds and large ECAP amplitudes, averaged across electrodes, tended to have higher speech perception scores. These results suggest a potential clinical role for the ECAP in the objective assessment of individual cochlear implant channels, with the potential to improve speech perception outcomes. PMID:26926152

  8. [Evoked potentials and inhalation anesthetics].

    Science.gov (United States)

    Thiel, A; Russ, W; Hempelmann, G

    1988-01-01

    Intraoperative monitoring of evoked potentials can be affected by various factors including volatile anaesthetics. These effects have to be considered in order to give correct interpretations of the obtained data. Visual evoked potentials (VEP) and auditory evoked potentials (AEP) will show strong alterations under general anaesthesia whereas brainstem auditory evoked potentials (BAEP) are slightly affected. The effects of nitrous oxide, halothane, enflurane, and isoflurane on somatosensory evoked potentials (SEP) after median nerve stimulation were studied in 35 healthy adult patients. pCO2 and tympanic membrane temperature were held constant. Simultaneous cervical and cortical SEP recording was performed using surface electrodes. After induction of anaesthesia SEP were recorded during normoventilation with 100% oxygen and after inhalation of 66.6% nitrous oxide. 10 patients received halothane at inspired concentrations of 0.5, 1.0, 1.5, and 2.0%. After nitrous oxide had been replaced by oxygen, halothane was reduced in steps of 0.5%. SEP were recorded at the end of each period (15 min). Equipotent doses of enflurane or isoflurane were administered to 15 and 10 patients, respectively. Nitrous oxide depressed early cortical SEP amplitude. Halothane, enflurane, and isoflurane caused dose dependent increases of latencies. Reduction of amplitude was most pronounced with isoflurane. Using high doses of enflurane in oxygen cortical SEP showed unusual high amplitudes associated with marked increases of latencies. Even under high concentrations of volatile anaesthetics cervical SEP were minimally affected. The effects of anaesthetic gases have to be considered when SEP are recorded intraoperatively.

  9. Vestibular-evoked myogenic potentials.

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    Colebatch, J G; Rosengren, S M; Welgampola, M S

    2016-01-01

    The vestibular-evoked myogenic potential (VEMP) is a short-latency potential evoked through activation of vestibular receptors using sound or vibration. It is generated by modulated electromyographic signals either from the sternocleidomastoid muscle for the cervical VEMP (cVEMP) or the inferior oblique muscle for the ocular VEMP (oVEMP). These reflexes appear to originate from the otolith organs and thus complement existing methods of vestibular assessment, which are mainly based upon canal function. This review considers the basis, methodology, and current applications of the cVEMP and oVEMP in the assessment and diagnosis of vestibular disorders, both peripheral and central. PMID:27638068

  10. Ocular Vestibular Evoked Myogenic Potentials

    OpenAIRE

    Felipe, Lilian; Kingma, Herman

    2013-01-01

    Introduction Diagnostic testing of the vestibular system is an essential component of treating patients with balance dysfunction. Until recently, testing methods primarily evaluated the integrity of the horizontal semicircular canal, which is only a portion of the vestibular system. Recent advances in technology have afforded clinicians the ability to assess otolith function through vestibular evoked myogenic potential (VEMP) testing. VEMP testing from the inferior extraocular muscles of the ...

  11. Ocular Vestibular Evoked Myogenic Potentials

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    Felipe, Lilian

    2014-01-01

    Full Text Available Introduction Diagnostic testing of the vestibular system is an essential component of treating patients with balance dysfunction. Until recently, testing methods primarily evaluated the integrity of the horizontal semicircular canal, which is only a portion of the vestibular system. Recent advances in technology have afforded clinicians the ability to assess otolith function through vestibular evoked myogenic potential (VEMP testing. VEMP testing from the inferior extraocular muscles of the eye has been the subject of interest of recent research. Objective To summarize recent developments in ocular VEMP testing. Results Recent studies suggest that the ocular VEMP is produced by otolith afferents in the superior division of the vestibular nerve. The ocular VEMP is a short latency potential, composed of extraocular myogenic responses activated by sound stimulation and registered by surface electromyography via ipsilateral otolithic and contralateral extraocular muscle activation. The inferior oblique muscle is the most superficial of the six extraocular muscles responsible for eye movement. Therefore, measurement of ocular VEMPs can be performed easily by using surface electrodes on the skin below the eyes contralateral to the stimulated side. Conclusion This new variation of the VEMP procedure may supplement conventional testing in difficult to test populations. It may also be possible to use this technique to evaluate previously inaccessible information on the vestibular system.

  12. [Intraoperative Visual Evoked Potential Monitoring].

    Science.gov (United States)

    Hayashi, Hironobu; Kawaguchi, Masahiko

    2015-05-01

    Visual evoked potential (VEP) is recorded from the back of the head, which is elicited by retinal stimulation transmitted through optic nerve, optic chiasm, optic tract lateral geniculate body, optic radiation and finally cortical visual area. VEP monitoring did not prevail since 1990s because marked intra-individual difference and instability of VEP recording limited the clinical usefulness under inhalation anesthetic management and techniques of VEP monitoring at the time. However, recent advances in techniques including a new light-stimulating device consisting of high-luminosity LEDs and induction of electroretinography to ascertain the arrival of the stimulus at the retina provided better conditions for stable VEP recording under general anesthesia. In addition, the introduction of total intravenous anesthesia using propofol is important for the successful VEP recordings because inhaled anesthetics have suppressive effect on VEP waveform. Intraoperative VEP has been considered to monitor the functional integrity of visual function during neurosurgical procedures, in which the optic pathway is at a risk of injury. Intraoperative VEP monitoring may allow us to detect reversible damage to the visual pathway intraoperatively and enable us to prevent permanent impairment.

  13. [The disposing techniques of evoked potentials].

    Science.gov (United States)

    Liu, H G; Zhou, L; Gu, J; Jing, D Z

    2000-11-01

    This paper is to bring forward the new disposing techniques of evoked potentials which include four aspect techniques of the averaging, the recording, digital sampling and filters about the averaging, evoked potential amplitude, evoked potential latency, evoked potential recording, and evoked potential generations. The technique of the averaging including signal filtering and a periodic averaging, can enhance EP dedection. The commercial EP machines also plot changes in latency between serial EP studies in order to detect trends in peak latency. The modern digital EP recording device consists of sensory stimator, recording amplifiers with analog filters, an analog-to-digital converter, a digital signal averager, and a display and storage system. A sample-and-hold function is one of the recent developments which used EP collectors that provide simultaneous recording with multiple channels employing different time and voltage scales and sampling rates. The EP data may be further processed following A-D conversion by digital filters. PMID:12583248

  14. Design and application of measuring system of evoked compound action potential%诱发动作电位测量系统的设计与应用

    Institute of Scientific and Technical Information of China (English)

    孟丽; 李平; 訾蕊; 费兴波

    2015-01-01

    目的:为获得电信号刺激神经纤维时的动作电位,本文设计了一种电诱发复合动作电位测量系统,解决了诱发动作电位的精确采集问题,有效去除了本底噪声的影响。方法分析了范围在十几微伏的电诱发复合动作电位到几十毫伏电极电位测量时存在的难点,以及一个测量系统正常工作时需要满足的测量放大器共模容限和差模容限及电流源电压容限问题。基于此,本文提出采用3级运算放大器级联的方式实现诱发动作电位的采集。系统主要由3级级联放大器、自动零点调整环节和基准电压部分组成,实现对弱信号的放大、消除本底噪声和提供过压保护。结果采用本文设计的系统,测量得到11 mV 的蛙类坐骨神经干复合动作电位和17μV 的豚鼠耳蜗电诱发复合动作电位,验证了本系统可有效测量各种诱发电位。结论采用3级放大器级联的方式和自动零点跟踪方式解决了微弱信号的有效放大和精确采集技术,为进一步研究通过电信号直接刺激神经纤维所产生的动作电位的特性提供可靠的测量手段。%Objective When the nerve fiber is stimulated by the electrical pulse,there is an evoked compound action potential which indicates the synchronism property of the nerve fiber. In order to obtain the precise action potential,a measuring system of evoked compound action potential is presented in this paper. The system can collect the compound action potential precisely and eliminate the effect of ground noise. Methods Firstly,we analyzed the difficulty in the measurement of the compound action potential which ranged from μV level to the mV level. Secondly,we discussed the common-mode tolerance,differential mode tolerance and the voltage margin of the electric current which guaranteed the proper functioning of the measuring system. Based on the issues,we proposed a measuring system of compound action

  15. Visual Evoked Potentials in Rett Syndrome

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    J. Gordon Millichap

    2015-11-01

    Full Text Available Investigators from the Boston Children's Hospital recorded pattern-reversal visual evoked potentials (VEPs in Mecp2 heterozygous female mice and in 34 girls with Rett syndrome (RTT.

  16. Evoked potentials in neuroinfections in children

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    V. N. Komantsev

    2013-01-01

    Full Text Available We present the results of the neurophysiological study in which 95 children with viral encephalitis and 30 children with meningitis (age from 2 up to 17 years undergo evoked potentials investigation. Some specific features of evoked potentials in neuroinfections have been shown to correlate with the course of disease and the age of the patients. We give a description of a logistic model of predicting outcomes in such patients by complex diagnostic method. We have found that evoked potentials may be successfully implemented in correcting the therapeutic strategies. Study of evoked potentials in neuroinfections in children can define the severity and extent of lesions and help to identify subclinical dysfunction and monitor the recovery processes under the therapy.

  17. Recording and analysis of electrically evoked compound action potentials (ECAPs) with MED-EL cochlear implants and different artifact reduction strategies in Matlab.

    Science.gov (United States)

    Bahmer, Andreas; Peter, Otto; Baumann, Uwe

    2010-08-15

    Electrically evoked compound action potentials (ECAPs) are used in auditory research to evaluate the response of the auditory nerve to electrical stimulation. Animal preparations are typically used for the recording. With the introduction of a new generation of cochlear implants, however it is possible to record the response of the auditory nerve to electrical stimulation in humans as well, which is used in the clinic to test whether the implant works properly and whether the auditory nerve is responsive. Currently, ECAPs are used to estimate thresholds for speech processor programs. In addition, ECAPs recordings allow new research to be addressed, e.g., to evaluate enhanced electrical stimulation patterns. Research platforms are required to test user-defined stimuli and algorithms for the ECAPs analysis. Clinical fitting software that records ECAPs is not flexible enough for this purpose. To enable a larger group of scientists to pursue research in this field, we introduce a flexible setup that allows to change stimulation and recording parameters. ECAP recording and analysis software was developed in Matlab (The Mathworks, Inc.) for standard PC, using a National instruments (PCI-6533, National Instruments, Austin, TX) card and a Research Interface Box 2 (RIB2, Department of Ion Physics and Applied Physics at the University of Innsbruck, Innsbruck, Austria) for MED-EL cochlear implants. ECAP recordings of a human subject with three different artifact reduction methods (alternating, Miller modified masker-probe, triphasic pulses) are presented and compared.

  18. A simple model for the generation of the vestibular evoked myogenic potential (VEMP)

    NARCIS (Netherlands)

    Wit, HP; Kingma, CM

    2006-01-01

    Objective: To describe the mechanism by which the vestibular evoked myogenic potential is generated. Methods: Vestibular evoked myogenic potential generation is modeled by adding a large number of muscle motor unit action potentials. These action potentials occur randomly in time along a 100 ms long

  19. Visual evoked potentials in the horse

    OpenAIRE

    Ström, L.; Ekesten, B.

    2016-01-01

    Background Electrical potentials generated in the central nervous system in response to brief visual stimuli, flash visual evoked potentials (FVEPs), can be recorded non-invasively over the occipital cortex. FVEPs are used clinically in human medicine and also experimentally in a number of animal species, but the method has not yet been evaluated in the horse. The method would potentially allow the ophthalmologist and equine clinician to evaluate visual impairment caused by disorders affectin...

  20. Intraoperative monitoring of evoked potentials.

    Science.gov (United States)

    Raudzens, P A

    1982-01-01

    Sensory EPs were recorded intraoperatively in 173 neurosurgical procedures (71 VEPs, 66 BAEPs, and 31 SSEPs) to evaluate the utility of this technique. EPs could be safely recorded in all cases, but the yield of useful results varied with each sensory modality. BAEPs were recorded reliably in 100% of the cases and intraoperative latency changes accurately predicted postoperative hearing deficits in 10%. Potential hearing deficits were detected in another 15%. BAEP changes were associated with brainstem dysfunction in only one case. VEP changes were difficult to interpret intraoperatively because of contamination by a high degree of variability and both false negative and false positive results. Changes in VEP amplitudes related to surgical manipulation of the optic chiasm were only suggested. SSEP changes were recorded reliably in only 75% of the cases and no correlations between SSEP changes and postoperative sensory function were established. Again, intraoperative amplitude attenuation of the SSEP waveform with surgical manipulation only suggested a potential sensory deficit. Intraoperative EP monitoring is a valuable technique that provides a functional analysis of the sensory nervous system during surgical procedures. Specific sensory stimuli and improved data analysis will increase the utility of this CNS monitor.

  1. Site of cochlear stimulation and its effect on electrically evoked compound action potentials using the MED-EL standard electrode array

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    Helbig Silke

    2009-12-01

    Full Text Available Abstract Background The standard electrode array for the MED-EL MAESTRO cochlear implant system is 31 mm in length which allows an insertion angle of approximately 720°. When fully inserted, this long electrode array is capable of stimulating the most apical region of the cochlea. No investigation has explored Electrically Evoked Compound Action Potential (ECAP recordings in this region with a large number of subjects using a commercially available cochlear implant system. The aim of this study is to determine if certain properties of ECAP recordings vary, depending on the stimulation site in the cochlea. Methods Recordings of auditory nerve responses were conducted in 67 subjects to demonstrate the feasibility of ECAP recordings using the Auditory Nerve Response Telemetry (ART™ feature of the MED-EL MAESTRO system software. These recordings were then analyzed based on the site of cochlear stimulation defined as basal, middle and apical to determine if the amplitude, threshold and slope of the amplitude growth function and the refractory time differs depending on the region of stimulation. Results Findings show significant differences in the ECAP recordings depending on the stimulation site. Comparing the apical with the basal region, on average higher amplitudes, lower thresholds and steeper slopes of the amplitude growth function have been observed. The refractory time shows an overall dependence on cochlear region; however post-hoc tests showed no significant effect between individual regions. Conclusions Obtaining ECAP recordings is also possible in the most apical region of the cochlea. However, differences can be observed depending on the region of the cochlea stimulated. Specifically, significant higher ECAP amplitude, lower thresholds and steeper amplitude growth function slopes have been observed in the apical region. These differences could be explained by the location of the stimulating electrode with respect to the neural tissue

  2. Analysis of evoked lumbosacral potentials in man.

    Science.gov (United States)

    Delbeke, J; McComas, A J; Kopec, S J

    1978-04-01

    Surface electrodes have been used to record potentials evoked in the lumbosacral region of 15 healthy volunteers after tibial nerve stimulation. By monitoring the M waves and H reflexes in the triceps surae muslces and by comparing the responses recorded over the roots with those over the lower cord, it was possible to identify the neural substrates responsible for several of the components in the responses. The findings are compared with those of previous studies in man and in other mammalian preparations. PMID:650237

  3. RECORDING OF VESTIBULAR EVOKED MYOGENIC POTENTIALS

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    A. A. Sazgar

    2006-05-01

    Full Text Available It has been shown recently that loud clicks evoke myogenic potentials in the tonically contracting sternocleidomastoid muscles. Studies have suggested that these potentials are of vestibular origin, especially of the saccule and inferior vestibular nerve. A pilot study was undertaken in our hospital to record vestibular evoked myogenic potentials (VEMP for the first time in Iran. Eighteen healthy volunteers (32 ears without history of otologic or vestibular disorders were subjected to the VEMP test. Twenty-one patients (26 ears with unilateral (6 patients and bilateral (5 patients high frequency sensorineural hearing loss with unknown etiology, acoustic neuroma (1 patient, Meniere’s disease (4 patients and unilateral low frequency sensorineural hearing loss without vestibular complaint (5 patients were also enrolled in this study. VEMP response to clicks was obtained from 84.4% of ears of healthy subjects. These subjects demonstrated short latency waves to click stimuli during tonic neck flexor activation. Mean latencies of first positive (p13 and first negative (n23 potentials in healthy subjects were 12.45 ± 1.9 ms and 20.8 ± 3.5 ms, respectively. Median latencies of these two potentials were 12.1 and 19.3 ms, respectively. We could record VEMP in 5 patients with unilateral and all patients with high and low frequency sensorineural hearing loss without vestibular complaint. In the patient with acoustic neuroma VEMP was absent on the affected side. This technique may offer a new method to evaluate otolith and sacculocollic pathways in human.

  4. Cervical vestibular evoked myogenic potentials in children

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    Alcione Botelho Pereira

    2015-08-01

    Full Text Available INTRODUCTION: Cervical vestibular evoked myogenic potential is a test used in neurotological examination. It verifies the integrity of vestibular function through a muscular response evoked by an acoustic stimulation which activates the saccular macula. Normal standards in adults have been established, however, there are few published data on the normal responses in children.OBJECTIVE: To establish normal standards for vestibular myogenic responses in children without neurotological complaints.METHODS: This study's design is a cohort with cross-sectional analysis. The sample consisted of 30 subjects, 15 females (50% and 15 males (50%.RESULTS: The age of the subjects ranged between 8 and 13 years, with a mean of 10.2 (± 1.7. P1 peak showed an average latency of 17.26 (± 1.78 ms and a mean amplitude of 49.34 (± 23.07 µV, and the N2 peak showed an average latency of 24.78 (± 2.18 ms and mean amplitude of 66.23 (± 36.18 µV. P1-N2 mean amplitude was 115.6 (± 55.7 µV. There were no statistically significant differences when comparing by gender or by laterality.CONCLUSION: We established normal values of cervical myogenic vestibular responses in children between 8 and 13 years without neurotological complaints.

  5. Resting Heart Rate and Auditory Evoked Potential

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    Simone Fiuza Regaçone

    2015-01-01

    Full Text Available The objective of this study was to evaluate the association between rest heart rate (HR and the components of the auditory evoked-related potentials (ERPs at rest in women. We investigated 21 healthy female university students between 18 and 24 years old. We performed complete audiological evaluation and measurement of heart rate for 10 minutes at rest (heart rate monitor Polar RS800CX and performed ERPs analysis (discrepancy in frequency and duration. There was a moderate negative correlation of the N1 and P3a with rest HR and a strong positive correlation of the P2 and N2 components with rest HR. Larger components of the ERP are associated with higher rest HR.

  6. Auditory evoked potential measurements in elasmobranchs

    Science.gov (United States)

    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.

  7. Auditory evoked potential measurements with cetaceans

    Science.gov (United States)

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

    2005-04-01

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

  8. [Intraoperative monitoring of visual evoked potentials].

    Science.gov (United States)

    Sasaki, Tatsuya; Ichikawa, Tsuyoshi; Sakuma, Jun; Suzuki, Kyouichi; Matsumoto, Masato; Itakura, Takeshi; Kodama, Namio; Murakawa, Masahiro

    2006-03-01

    Our success rate of intraoperative monitoring of visual evoked potential (VEP) had been approximately 30% in the past. In order to improve recording rate of intraoperative VEP, we developed a new stimulating device using high power light emitting diodes. Electroretinogram was simultaneously recorded to understand whether flash stimulation reached the retina. In addition, total venous anesthesia with propofol was used to avoid the adverse effect of inhalation anesthesia. We report the results after introduction of these improvements. Intraoperative monitoring of VEP was attempted in 35 cases. We evaluated success rate of VEP recording, correlation between VEP findings and postoperative visual function, and reasons why recording was not successful. Stable and reproducible waveforms were obtained in 59 sides (84%). Two cases, whose VEP deteriorated intraoperatively, developed postoperative visual disturbance: In 11 sides (16%), stable waveforms were not obtained. There were two main causes. In 8 sides out of 11, the cause was attributed to pre-existing severe visual disturbance. In these 8 sides, VEP in the awake state was not recordable or was recordable, but with very low amplitudes under 1 microV. In the other 3 sides, the cause was attributed to movement of a stimulating device by reflecting the fronto-temporal scalp flap. In conclusion, the successful recording rate was increased to 84% from approximately 30%, after introduction of various trials. We need further improvement in recording intraoperative VEP to establish a reliable intraoperative monitoring method for VEP.

  9. Multimodal evoked potential abnormalities in patients with Wilson's disease

    Directory of Open Access Journals (Sweden)

    Ilić Tihomir V.

    2005-01-01

    Full Text Available The aim of this study was to investigate the involvement of the following functional systems: somatosensory evoked potentials (SSEP, visual evoked potentials (VEP, and event related potentials (ERP, in twenty patients with Wilson's disease (WD. VEP and SSEP abnormalities were discovered in S patients respectively (40%, whereas ERP were either absent or, in the case of 10 patients (50%, had significantly prolonged P-300 latencies. Taken together, at least one evoked potential abnormality was discovered in 17 patients (85%]. Only in 3 patients (15%, involving either the isolated hepatic type of disease or short illness duration of the neurological type, were normal evoked potential findings observed. Our findings suggest the usefulness of multimodal evoked potential abnormalities in the evaluation of subclinical manifestations in patients with WD.

  10. Somatosensory evoked potentials by paraspinal stimulation in acute transverse myelitis.

    Directory of Open Access Journals (Sweden)

    Murthy J

    1999-04-01

    Full Text Available Somatosensory evoked potentials by paraspinal stimulation were studied in 6 patients with acute transverse myelitis. In one patient in whom posterior tibial somatosensory evoked potentials were not recordable, a poorly formed response was seen with paraspinal stimulation. Slowing of conduction across the involved segment was seen in the remaining 5 patients and fairly correlated with the clinical localization.

  11. Somatosensory evoked potentials by paraspinal stimulation in acute transverse myelitis.

    OpenAIRE

    Murthy J

    1999-01-01

    Somatosensory evoked potentials by paraspinal stimulation were studied in 6 patients with acute transverse myelitis. In one patient in whom posterior tibial somatosensory evoked potentials were not recordable, a poorly formed response was seen with paraspinal stimulation. Slowing of conduction across the involved segment was seen in the remaining 5 patients and fairly correlated with the clinical localization.

  12. Cortical evoked potentials recorded from the guinea pig without averaging.

    Science.gov (United States)

    Walloch, R A

    1975-01-01

    Potentials evoked by tonal pulses and recorded with a monopolar electrode on the pial surface over the auditory cortex of the guinea pig are presented. These potentials are compared with average potentials recorded in previous studies with an electrode on the dura. The potentials recorded by these two techniques have similar waveforms, peak latencies and thresholds. They appear to be generated within the same region of the cerebral cortex. As can be expected, the amplitude of the evoked potentials recorded from the pial surface is larger than that recorded from the dura. Consequently, averaging is not needed to extract the evoked potential once the dura is removed. The thresholds for the evoked cortical potential are similar to behavioral thresholds for the guinea pig at high frequencies; however, evoked potential thresholds are eleveate over behavioral thresholds at low frequencies. The removal of the dura and the direct recording of the evoked potential appears most appropriate for acute experiments. The recording of an evoked potential with dura electrodes empploying averaging procedures appears most appropriate for chronic studies.

  13. [Brainstem auditory evoked potentials and somatosensory evoked potentials in Chiari malformation].

    Science.gov (United States)

    Moncho, Dulce; Poca, María A; Minoves, Teresa; Ferré, Alejandro; Rahnama, Kimia; Sahuquillo, Juan

    2013-06-16

    Introduccion. La malformacion de Chiari (MC) incluye una serie de anomalias congenitas que tienen como comun denominador la ectopia de las amigdalas del cerebelo por debajo del foramen magno, lo que puede condicionar fenomenos compresivos del troncoencefalo, la medula espinal alta y los nervios craneales, alterando las respuestas de los potenciales evocados auditivos del tronco cerebral (PEATC) y de los potenciales evocados somatosensoriales (PESS). Sin embargo, las indicaciones de ambas exploraciones en las MC han sido motivo de estudio en un numero limitado de publicaciones, centradas en series cortas y heterogeneas de pacientes. Objetivo. Revisar los hallazgos de los PEATC y los PESS en los estudios publicados en pacientes con MC tipo 1 (MC-1) o tipo 2 (MC-2), y su indicacion en el diagnostico, tratamiento y seguimiento, especialmente en la MC-1. Desarrollo. Es un estudio de revision realizado mediante analisis de los estudios publicados en Medline desde 1966, localizados mediante PubMed, utilizando combinaciones de las palabras clave 'Chiari malformation', 'Arnold-Chiari malformation', 'Chiari type 1 malformation', 'Arnold-Chiari type 1 malformation', 'evoked potentials', 'brainstem auditory evoked potentials' y 'somatosensory evoked potentials', asi como informacion de pacientes con MC-1 valorados en los servicios de neurocirugia y neurofisiologia clinica del Hospital Universitari Vall d'Hebron. Conclusiones. Los hallazgos mas comunes de los PESS son la reduccion en la amplitud cortical para el nervio tibial posterior, la reduccion o ausencia del potencial cervical del nervio mediano y el aumento del intervalo N13-N20. En el caso de los PEATC, los hallazgos mas frecuentes descritos son el aumento del intervalo I-V y la alteracion periferica o coclear.

  14. Pudendal somatosensory evoked potentials in normal women

    Directory of Open Access Journals (Sweden)

    Geraldo A. Cavalcanti

    2007-12-01

    Full Text Available OBJECTIVE: Somatosensory evoked potential (SSEP is an electrophysiological test used to evaluate sensory innervations in peripheral and central neuropathies. Pudendal SSEP has been studied in dysfunctions related to the lower urinary tract and pelvic floor. Although some authors have already described technical details pertaining to the method, the standardization and the influence of physiological variables in normative values have not yet been established, especially for women. The aim of the study was to describe normal values of the pudendal SSEP and to compare technical details with those described by other authors. MATERIALS AND METHODS: The clitoral sensory threshold and pudendal SSEP latency was accomplished in 38 normal volunteers. The results obtained from stimulation performed on each side of the clitoris were compared to ages, body mass index (BMI and number of pregnancies. RESULTS: The values of clitoral sensory threshold and P1 latency with clitoral left stimulation were respectively, 3.64 ± 1.01 mA and 37.68 ± 2.60 ms. Results obtained with clitoral right stimulation were 3.84 ± 1.53 mA and 37.42 ± 3.12 ms, respectively. There were no correlations between clitoral sensory threshold and P1 latency with age, BMI or height of the volunteers. A significant difference was found in P1 latency between nulliparous women and volunteers who had been previously submitted to cesarean section. CONCLUSIONS: The SSEP latency represents an accessible and reproducible method to investigate the afferent pathways from the genitourinary tract. These results could be used as normative values in studies involving genitourinary neuropathies in order to better clarify voiding and sexual dysfunctions in females.

  15. Multichannel recording of median nerve somatosensory evoked potentials

    NARCIS (Netherlands)

    van de Wassenberg, W.; van der Hoeven, J.; Leenders, K.; Maurits, N.

    2008-01-01

    Objectives. -Clinical applications of multichannel (>= 64 electrodes) electroencephalography (EEG) have been limited so far. Amplitude variability of evoked potentials in healthy subjects is large, which limits their diagnostic applicability. This amplitude variability may be partially due to spatia

  16. Stimulator with arbitrary waveform for auditory evoked potentials

    Energy Technology Data Exchange (ETDEWEB)

    Martins, H R; Romao, M; Placido, D; Provenzano, F; Tierra-Criollo, C J [Universidade Federal de Minas Gerais (UFMG), Departamento de Engenharia Eletrica (DEE), Nucleo de Estudos e Pesquisa em Engenharia Biomedica NEPEB, Av. Ant. Carlos, 6627, sala 2206, Pampulha, Belo Horizonte, MG, 31.270-901 (Brazil)

    2007-11-15

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

  17. Value of transcranial motor evoked potentials during spinal operations

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    @@ To the Editor: We read the interesting recent article by Ding et al1 concerning the value of somatosensory evoked potentials (SEPs) in the diagnosis and prognosis of cervical spondylotic myelopathy, as well as the usefulness of monitoring intraoperative potentials in terms of safety and predictive factors.

  18. INTRAOPERATIVE LOCALIZATION OF CORTICAL MOTOR EVOKED POTENTIALS IN CENTRAL SULCUS LESIONS

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Objective To study direct cortical electrical stimulation technique for the recording of motor evoked potentials under general anesthesia in central sulcus lesions. Methods The largest N20-P25 response was recorded from postcentral gyrus by intraoperative monitoring of cortical motor evoked potentials in 10 patients with intracranial lesions near or in the central area. The muscles of upper extremity in all patients were activated by delivering stimulus to cortical areas continuously. Moving the cortical electrodes forward, the largest P20-N25 response, SEP phase reversal,was obtained as a motor center stimulus. In this site of cortex, a short train stimulation elicited reproducible muscle action potentials that could be observed from the oscilloscope without averaging.Results MEPs can be recorded, pre- and post-operatively, without motor deficits of upper limbs in all patients.Conclusion This technique seems to be preferable for intraoperative localization of motor evoked potentials in central sulcus lesions under total intravenous anesthesia.

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

    Science.gov (United States)

    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. [Evoked potentials in intracranial operations: current status and our experiences].

    Science.gov (United States)

    Nau, H E; Hess, W; Pohlen, G; Marggraf, G; Rimpel, J

    1987-03-01

    Intraoperative neuromonitoring, especially evoked potential monitoring, has gained interest in recent years for both the anesthesiologist evaluating cerebral function and the neurosurgeon wishing to avoid neuronal lesions during intracranial operations. Before evoked potential monitoring can be introduced as a routine method of intraoperative management, experience with this method particularly in intensive care units, is imperative. We recorded evoked potentials with the Compact Four (Nicolet) and Basis 8000 (Schwarzer Picker International) computer systems. Preoperative derivations should be done with the same apparatus used intraoperatively and parameters of peri- and intraoperative derivations should not be changed. The patient's head must be fixed in a Mayfield clamp in order to avoid artefacts during trepanation. The possible artefacts due to apparatus, patient, or anesthesia are summarized in the tables. The derivations of evoked potentials should be supervised by a person who is not involved in the anesthesia or the surgical procedure; this condition may change in the future with full automatization of the recording technique and alarms. Good communication between surgeon, anesthesiologist, and neurophysiological assistant is a prerequisite. The modality is chosen in accordance with the affected neuronal system: visual-evoked potential (VEP) monitoring in the management of processes affecting the visual pathway, brain stem auditory-(BAER) and somatosensory-evoked potential (SSEP) monitoring in lesions affecting these pathways, in particular space-occupying lesions of the posterior fossa. VEP monitoring may be useful, but we observed alterations of the responses without changes in the level of anesthesia or manipulation of the visual pathways. In space-occupying processes of the cerebellopontine angle, BAER could not be developed in nearly all cases because the large underlying tumor had caused the disappearance of waves II-V. In these cases SSEP monitoring

  1. Auditory evoked potentials and impairments to psychomotor activity evoked by falling asleep.

    Science.gov (United States)

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

    2010-05-01

    Sounds provide the most suitable stimuli for studies of information processes occurring in the brain during falling asleep and at different stages of sleep. The widely used analysis of evoked potentials averaged for groups of subjects has a number of disadvantages associated with their individual variability. Thus, in the present study, measures of the individual components of auditory evoked potentials were determined and selectively summed for individual subjects, with subsequent analysis by group. The aim of the present work was to identify measures of auditory evoked potentials providing quantitative assessment of the dynamics of the brain's functional state during the appearance of errors in activity associated with decreases in the level of waking and falling asleep. A monotonous psychomotor test was performed in the lying position with the eyes closed; this consisted of two alternating parts: the first was counting auditory stimuli from 1 to 10 with simultaneous pressing of a button, and the second was counting stimuli from 1 to 5 silently without pressing the button, and so on. Computer-generated sound stimuli (duration 50 msec, envelope filling frequency 1000 Hz, intensity 60 dB) were presented binaurally with interstimulus intervals of 2.4-2.7 sec. A total of 41 subjects took part (both genders, mean age 25 years), of which only 23 fell asleep; data for 14 subjects with sufficient episodes of falling asleep were analyzed. Comparison of measures of auditory evoked potentials (the latencies and amplitudes of the N1, P2, N2, and P3 components) during correct and erroneous psychomotor test trials showed that decreases in the level of consciousness elicited significant increases in the amplitudes of the components of the vertex N1-P2-N2 complex in series without button pressing. The greatest changes in auditory evoked potentials in both series were seen in the N2 component, with latency 330-360 msec, which has a common origin with the EEG theta rhythm and is

  2. Asymmetric vestibular evoked myogenic potentials in unilateral Meniere patients

    NARCIS (Netherlands)

    Kingma, C. M.; Wit, H. P.

    2011-01-01

    Vestibular evoked myogenic potentials (VEMPs) were measured in 22 unilateral MeniSre patients with monaural and binaural stimulation with 250 and 500 Hz tone bursts. For all measurement situations significantly lower VEMP amplitudes were on average measured at the affected side compared to the unaff

  3. Cortical Auditory Evoked Potentials in Unsuccessful Cochlear Implant Users

    Science.gov (United States)

    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…

  4. SOMATOSENSORY EVOKED-POTENTIALS IN CEREBRAL ANEURYSM SURGERY

    NARCIS (Netherlands)

    BUCHTHAL, A; BELOPAVLOVIC, M

    1992-01-01

    Monitoring of median nerve somatosensory evoked potentials (SSEP) during surgery for a basilar artery aneurysm under moderate hypothermia revealed an unexpected loss of the first cortical peak. This was due to compression of the middle cerebral artery under the retractor during the surgical approach

  5. Multichannel recording of tibial-nerve somatosensory evoked potentials

    NARCIS (Netherlands)

    de Wassenberg, W. J. G. van; Kruizinga, W. J.; van der Hoeven, J. H.; Leenders, K. L.; Maurits, N. M.

    2008-01-01

    Study aims. -The topography of the peaks of tibial.-nerve somatosensory evoked potential (SEP) varies among healthy subjects, most likely because of differences in position and orientation of their cortical generator(s). Therefore, amplitude estimation with a standard one- or two-channel derivation

  6. An evoked potential mapping of transcallosal projections in the cat

    OpenAIRE

    A. Cukiert; C. Timo-Iaria

    1989-01-01

    In ten adult cats anesthetized with ketamine hydrochloride the neocortex was exposed and rectangular pulses (1msec, 0.5 Hz and variable intensity) were applied to discrete points of one side and transcallosal evoked potentials were recorded from the other. The stimulation and recording positions were determined on a cartesian map of most of the exposable neocortical areas and the potentials were analysed as to their components, voltage and latency. Passive spread and electrotonic potentials a...

  7. Efeitos do potencial de ação neural sobre a percepção de fala em usuários de implante coclear Influence of evoked compound action potential on speech perception in cochlear implant users

    Directory of Open Access Journals (Sweden)

    Mariana Cardoso Guedes

    2007-08-01

    Full Text Available O Potencial de Ação Composto Evocado Eletricamente reflete a atividade do nervo auditivo, podendo ser registrado através dos eletrodos do implante coclear. A determinação dos elementos neurais estimuláveis pode contribuir para explicar a variabilidade de desempenho entre indivíduos implantados. OBJETIVO: Comparar o desempenho nos testes de percepção da fala entre pacientes que apresentaram e que não apresentaram potencial de ação composto evocado eletricamente no momento intra-operatório. MATERIAL E MÉTODO: Estudo prospectivo no qual 100 indivíduos usuários do implante coclear Nucleus 24 foram divididos em dois grupos de acordo com a presença ou ausência do potencial de ação intra-operatório. Após 6 meses de uso do dispositivo, os resultados dos testes de percepção de fala foram comparados entre os grupos. RESULTADOS: O potencial foi observado em 72% dos pacientes. A percepção no teste de frases em formato aberto foi melhor nos indivíduos com presença de potencial (média 82,8% contra 41,0%, p = 0,005. Houve associação entre ausência do potencial e etiologia da surdez por meningite. CONCLUSÃO: Ausência de potencial neural intraoperatório esteve associada ao pior desempenho na percepção da fala e à etiologia da surdez por meningite. Por outro lado, a presença do potencial de ação intraoperatório sugere ótimo prognóstico.Electrically Evoked Compound Action Potential is a measure of synchronous cochlear nerve fibers activity elicited by electrical stimulation of the cochlear implant. The electrophysiological nerve responses may contribute to explain the variability in individual performance of cochlear implant recipients. AIM: To compare speech perception tests’ performances of cochlear implant users according to the presence or absence of intraoperative neural telemetry responses. MATERIAL AND METHOD: Prospective study design with 100 "Nucleus 24" cochlear implant users divided in two groups according

  8. Vestibular-evoked myogenic potentials in miniature pigs

    Institute of Scientific and Technical Information of China (English)

    Xi Shi; Yan Zhang; Ya Li; Shiwei Qiu; Shili Zhang; Yaohan Li; Na Yuan; Yuehua Qiao; Shiming Yang

    2016-01-01

    Objective:To report detection of vestibular-evoked myogenic potentials (VEMPs) in the miniature pig. Methods:Potentials evoked by 1000 Hz tone bursts were recorded from neck extensor muscles and the masseter muscles in normal adult Bama miniature pigs anesthetized with 3%pentobarbital sodium and Carbachol II. Results:The latency of the first positive wave P from neck extensor muscles was 7.65 ± 0.64 ms, with an amplitude of 1.66 ± 0.34 uv and a rate of successful induction of 75%at 80 dB SPL. The latency of potentials evoked from the masseter muscles was 7.60 ± 0.78 ms, with an amplitude of 1.31 ± 0.28 uv and a rate successful induction of 66%at 80 dB SPL. Conclusion:The latencies and thresholds of VEMPs recorded from the neck extensor muscle and the masseter muscle appear to be comparable in normal adult Bama miniature pigs, although the amplitude recorded from the neck extensor muscle seems to be higher than that from the masseter muscle. However, because of their usually relatively superficial and easily accessible location, as well as their large volume and strong contractions, masseter muscles may be better target muscles for recording myogenic potentials.

  9. Abdominal acupuncture reduces laser-evoked potentials in healthy subjects

    DEFF Research Database (Denmark)

    Pazzaglia, C.; Liguori, S.; Minciotti, I.;

    2015-01-01

    Objective: Acupuncture is known to reduce clinical pain, although the exact mechanism is unknown. The aim of the current study was to investigate the effect of acupuncture on laser-evoked potential amplitudes and laser pain perception. Methods: In order to evaluate whether abdominal acupuncture...... is able to modify pain perception, 10 healthy subjects underwent a protocol in which laser-evoked potentials (LEPs) and laser pain perception were collected before the test (baseline), during abdominal acupuncture, and 15. min after needle removal. The same subjects also underwent a similar protocol...... in which, however, sham acupuncture without any needle penetration was used. Results: During real acupuncture, both N1 and N2/P2 amplitudes were reduced, as compared to baseline (p . < 0.01). The reduction lasted up to 15. min after needle removal. Furthermore, laser pain perception was reduced during...

  10. Single-sweep spectral analysis of contact heat evoked potentials

    DEFF Research Database (Denmark)

    Hansen, Tine M; Graversen, Carina; Frøkjaer, Jens B;

    2015-01-01

    AIMS: The cortical response to nociceptive thermal stimuli recorded as contact heat evoked potentials (CHEPs) may be altered by morphine. However, previous studies have averaged CHEPs over multiple stimuli, which are confounded by jitter between sweeps. Thus, the aim was to assess single-sweep ch......AIMS: The cortical response to nociceptive thermal stimuli recorded as contact heat evoked potentials (CHEPs) may be altered by morphine. However, previous studies have averaged CHEPs over multiple stimuli, which are confounded by jitter between sweeps. Thus, the aim was to assess single...... by 13% (P = 0.04) and 9% (P = 0.007), while the beta and gamma bands were increased by 10% (P = 0.006) and 24% (P = 0.04). CONCLUSION: The decreases in the delta and theta band are suggested to represent a decrease in the pain specific morphology of the CHEPs, which indicates a diminished pain response...

  11. [Long-latency auditory evoked potentials in cochlear implants].

    Science.gov (United States)

    Mata, J J; Jiménez, J M; Pérez, J; Postigo, A; Roldán, B

    1999-01-01

    Cortical evoked potentials were evaluated in patients with cochlear implants. In a group of 8 adults of different ages, the lingual state before implantation and during rehabilitation were evaluated. Using cortical evoked potentials, the results of the P300 wave in response to two tones, one frequent (1,000 Hz) and the other infrequent (2,000 Hz), presented at 70 and 80 dB HL were studied. Results were analyzed and compared in relation to locutive state, rehabilitation stage, and intensity of stimulus. Absolute latencies did not differ significantly. However, latency values in relation to reaction time were significantly longer in prelingual than in postlingual patients (p test). The results confirmed the normality of central cognitive processes in patients with cochlear implants in objective assessment of P300 latency. The results suggest differences between prelingual and postlingual patients in relation to central signal processing.

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

    OpenAIRE

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

    2010-01-01

    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 dur...

  13. [Evoked cortical somatosensory potentials in painful cervicobrachial radicular syndromes].

    Science.gov (United States)

    Domzał, T; Marks, E; Miszczak, J

    1978-01-01

    The authors determined the subjective, objective and maximal pain threshold by means of electrical stimulation in two groups of subjects. Group I comprised healthy subjects, group II patients with right-sided radicular cervicobrachial pains. The method applied by the authors for objective determination of pain threshold with evoked cortical somatosensory potential differentiated both groups which suggests its practical usefulness in clinical practice and expertise. PMID:683429

  14. A Sequential Detection Method for Late Auditory Evoked Potentials

    OpenAIRE

    Hoppe, U; Eysholdt, U; Weiss, S.

    1996-01-01

    This work presents a novel mechanism for detection of late auditory evoked potentials (AEP). AEPs, which are an important diagnostic tool to detect hearing deficiencies, are contained within the electroencephalogram (EEG) at a very low SNR. Our proposed automatic detection of AEPs is based on the Wavelet-Transform of EEG data for feature extraction. Several transform coefficients are then used for a classification by a neural network; its decisions on successive EEG segments are judged by a s...

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

    OpenAIRE

    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...

  16. Influence of temperature on the sound-evoked vestibular potential.

    Science.gov (United States)

    Wit, H P; Dijkgraaf, E

    1985-01-01

    The sound-evoked vestibular potential, measured with gross electrodes after fenestration of a lateral semicircular canal in pigeons, is delayed with respect to the acoustic stimulus. The influence of temperature of the vestibular system on this delay can most easily be explained by assuming chemically mediated transmission to take place between vestibular hair cells and their primary afferents. The possibility of electrotonic transmission, however, cannot be excluded. PMID:3878654

  17. Somatosensory evoked potentials and outcome in perinatal asphyxia.

    OpenAIRE

    Gibson, N A; Graham, M.; Levene, M I

    1992-01-01

    Somatosensory evoked potentials (SEP) can be measured in the term newborn infant and given an index of function in the areas of the brain most likely to be damaged in perinatal asphyxia. We studied the median nerve SEP in 30 asphyxiated term infants over the course of their encephalopathy and until discharge from the neonatal unit. Three types of response were noted: normal waveform, abnormal waveform, or absence of cortical response. Follow up of the survivors was undertaken at a mean age of...

  18. [Visual evoked potentials (VEP) in anesthesia and intensive care].

    Science.gov (United States)

    Russ, W; Krumholz, W; Hempelmann, G

    1984-03-01

    Methodological considerations and different stimulation techniques of visual evoked potentials (VEP) are described. VEP can provide information about neurological function during anaesthesia, surgery and in the unconscious patient after head injury. The feasibility of the method for intraoperative monitoring in neuro- and cardiac surgery and the influence of general anaesthetics and other contributing factors such as temperature, paCO2, pO2, part are discussed.

  19. Perceptual learning of acoustic noise generates memory-evoked potentials.

    Science.gov (United States)

    Andrillon, Thomas; Kouider, Sid; Agus, Trevor; Pressnitzer, Daniel

    2015-11-01

    Experience continuously imprints on the brain at all stages of life. The traces it leaves behind can produce perceptual learning [1], which drives adaptive behavior to previously encountered stimuli. Recently, it has been shown that even random noise, a type of sound devoid of acoustic structure, can trigger fast and robust perceptual learning after repeated exposure [2]. Here, by combining psychophysics, electroencephalography (EEG), and modeling, we show that the perceptual learning of noise is associated with evoked potentials, without any salient physical discontinuity or obvious acoustic landmark in the sound. Rather, the potentials appeared whenever a memory trace was observed behaviorally. Such memory-evoked potentials were characterized by early latencies and auditory topographies, consistent with a sensory origin. Furthermore, they were generated even on conditions of diverted attention. The EEG waveforms could be modeled as standard evoked responses to auditory events (N1-P2) [3], triggered by idiosyncratic perceptual features acquired through learning. Thus, we argue that the learning of noise is accompanied by the rapid formation of sharp neural selectivity to arbitrary and complex acoustic patterns, within sensory regions. Such a mechanism bridges the gap between the short-term and longer-term plasticity observed in the learning of noise [2, 4-6]. It could also be key to the processing of natural sounds within auditory cortices [7], suggesting that the neural code for sound source identification will be shaped by experience as well as by acoustics.

  20. Short latency vestibular evoked potentials in the chicken embryo

    Science.gov (United States)

    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 birds. Mean response threshold for anesthetized embryos was -15.9dBre 1.0 g/ms, which was significantly higher (P 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 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.

  1. STUDY ON EVOKED POTENTIALS IN TYPE 2 DIABETIC PATIENTS

    Institute of Scientific and Technical Information of China (English)

    陈薇; 陈慎仁; 陈璇; 吴静珊; 刘兴材

    2003-01-01

    The aim of this study is to explore the changes of visual evoked potentiaK VEP), brainstem auditory evoked potential (BAEP), Somatosensory e-voked potential (SEP), event-related potential(ERP) of patients with type 2 diabetes mellitus(DM).Methods VEP, BAEP, SEP, ERP were measured in 30 cases with type 2 DM (DM group) and in 30 age- and sex-matched healthy volunteers (Control group) by using Nicolet Viking Ⅳ EMG/EP instrument. The numerical values of VEP, BAEP, SEP and ERP were recorded and analyzed by SPSS.Results Abnormalities were found as follows: VEP in 20(66.7%), BAEP in 18(60%), MNSEP in 20(66.7%),PTNSEP in 22(73.3%), and ERP in 11 (36.67%) diabetic patients, including the disappearance of wave, prolonged wave latency and decreased wave amplitude. Compared with control group, the P100 latency of VEP, the latencies of wave Ⅰ and Ⅴ, amplitude of wave Ⅴ, the interpeak latencies (IPL) of each wave in BAEP, the latencies and wave amplitudes in N9 to P20 of MNSEP and in N9 to P38 of PTNSEP, as well a

  2. Brainstem auditory evoked potential abnormalities in type 2 diabetes mellitus

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    Sharat Gupta

    2013-01-01

    Full Text Available Background: Diabetes mellitus represents a syndrome complex in which multiple organ systems, including the central nervous system, are affected. Aim: The study was conducted to determine the changes in the brainstem auditory evoked potentials in type 2 diabetes mellitus. Materials and Methods: A cross sectional study was conducted on 126 diabetic males, aged 35-50 years, and 106 age-matched, healthy male volunteers. Brainstem auditory evoked potentials were recorded and the results were analyzed statistically using student′s unpaired t-test. The data consisted of wave latencies I, II, III, IV, V and interpeak latencies I-III, III-V and I-V, separately for both ears. Results: The latency of wave IV was significantly delayed only in the right ear, while the latency of waves III, V and interpeak latencies III-V, I-V showed a significant delay bilaterally in diabetic males. However, no significant difference was found between diabetic and control subjects as regards to the latency of wave IV unilaterally in the left ear and the latencies of waves I, II and interpeak latency I-III bilaterally. Conclusion: Diabetes patients have an early involvement of central auditory pathway, which can be detected with fair accuracy with auditory evoked potential studies.

  3. Brainstem auditory evoked potentials in children with lead exposure

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    Katia de Freitas Alvarenga

    2015-02-01

    Full Text Available Introduction: Earlier studies have demonstrated an auditory effect of lead exposure in children, but information on the effects of low chronic exposures needs to be further elucidated. Objective: To investigate the effect of low chronic exposures of the auditory system in children with a history of low blood lead levels, using an auditory electrophysiological test. Methods: Contemporary cross-sectional cohort. Study participants underwent tympanometry, pure tone and speech audiometry, transient evoked otoacoustic emissions, and brainstem auditory evoked potentials, with blood lead monitoring over a period of 35.5 months. The study included 130 children, with ages ranging from 18 months to 14 years, 5 months (mean age 6 years, 8 months ± 3 years, 2 months. Results: The mean time-integrated cumulative blood lead index was 12 µg/dL (SD ± 5.7, range:2.433. All participants had hearing thresholds equal to or below 20 dBHL and normal amplitudes of transient evoked otoacoustic emissions. No association was found between the absolute latencies of waves I, III, and V, the interpeak latencies I-III, III-V, and I-V, and the cumulative lead values. Conclusion: No evidence of toxic effects from chronic low lead exposures was observed on the auditory function of children living in a lead contaminated area.

  4. Baroreceptor activation attenuates attentional effects on pain-evoked potentials.

    Science.gov (United States)

    Gray, Marcus A; Minati, Ludovico; Paoletti, Giulia; Critchley, Hugo D

    2010-12-01

    Focused attention typically enhances neural nociceptive responses, reflected electroencephalographically as increased amplitude of pain-evoked event-related potentials (ERPs). Additionally, pain-evoked ERPs are attenuated by hypertension and baroreceptor activity, through as yet unclear mechanisms. There is indirect evidence that these two effects may interact, suggesting that baroreceptor-related modulation of nociception is more than a low-level gating phenomenon. To address this hypothesis, we explored in a group of healthy participants the combined effects of cue-induced expectancy and baroreceptor activity on the amplitude of pain-evoked ERPs. Brief nociceptive skin stimuli were delivered during a simple visual task; half were preceded by a visual forewarning cue, and half were unpredictable. Nociceptive stimuli were timed to coincide either with systole (maximum activation of cardiac baroreceptors) or with diastole (minimum baroreceptor activation). We observed a strong interaction between expectancy and cardiac timing for the amplitude of the P2 ERP component; no effects were observed for the N2 component. Cued stimuli were associated with larger P2 amplitude, but this effect was abolished for stimuli presented during baroreceptor activation. No cardiac timing effect was observed for un-cued stimuli. Taken together, these findings suggest a close integration of cognitive-affective aspects of expectancy and baroreceptor influences on pain, and as such may cast further light on mechanisms underlying mental and physiological contributions to clinical pain.

  5. Cortical modulation of short-latency TMS-evoked potentials

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    Domenica eVeniero

    2013-01-01

    Full Text Available Transcranial magnetic stimulation - electroencephalogram (TMS-EEG co-registration offers the opportunity to test reactivity of brain areas across distinct conditions through TMS-evoked potentials (TEPs. Several TEPs have been described, their functional meaning being largely unknown. In particular, short-latency potentials peaking at 5 (P5 and 8 (N8 ms after the TMS pulse have been recently described, but because of their huge amplitude, the problem of whether their origin is cortical or not has been opened. To gain information about these components, we employed a protocol that modulates primary motor cortex excitability (MI through an exclusively cortical phenomena: low frequency stimulation of premotor area (PMC. TMS was applied simultaneously with EEG recording from 70 electrodes. Amplitude of TEPs evoked by 200 single-pulses TMS delivered over MI at 110% of resting motor threshold was measured before and after applying 900 TMS conditioning stimuli to left premotor cortex with 1 Hz repetition rate. Single subject analyses showed reduction in TEPs amplitude after PMC conditioning in a sample of participants and increase in TEPs amplitude in two subjects. No effects were found on corticospinal excitability as recorded by motor evoked potentials (MEPs. Furthermore, correlation analysis showed an inverse relation between the effects of the conditioning protocol on P5-N8 complex amplitude and MEPs amplitude. Because the effects of the used protocol have been ascribed to a cortical interaction between premotor area and MI, we suggest that despite the sign of P5-N8 amplitude modulation is not consistent across participant, this modulation could indicate, at least in part, their cortical origin. We conclude that with an accurate experimental procedure early-latency components can be used to evaluate the reactivity of the stimulated cortex.

  6. Clinical application of vestibular evoked myogenic potential (VEMP).

    Science.gov (United States)

    Murofushi, Toshihisa

    2016-08-01

    The author reviewed clinical aspects of vestibular evoked myogenic potentials (VEMPs). Now two types of VEMPs are available. The first one is cervical VEMP, which is recorded in the sternocleidomastoid muscle and predominantly reflects sacculo-collic reflex. The other is ocular VEMP, which is usually recorded below the lower eye lid and predominantly reflects utriculo-ocular reflex. VEMPs play important roles not only for assessment of common vestibular diseases but also for establishment of new clinical entities. Clinical application in Meniere's disease, vestibular neuritis, benign paroxysmal positional vertigo, vestibular migraine, idiopathic otolithic vertigo, and central vertigo/dizziness was reviewed. PMID:26791591

  7. Visual evoked potentials to colour change of a moving bar

    OpenAIRE

    Carolina eMurd; Kairi eKreegipuu; Nele eKuldkepp; Aire eRaidvee; Maria eTamm; Jüri eAllik

    2014-01-01

    In our previous study we found that it takes less time to detect colour change in a moving object compared to colour change in a stationary one (Kreegipuu et al., 2006, Vision Research 46(11), 1848-1855). Here, we replicated the experiment, but in addition to reaction times we measured visual evoked potentials, to see whether this effect of motion is revealed at the cortical level of information processing. We asked our subjects to detect colour changes in stationary (0º/s) and moving bars (4...

  8. Prognosis in prolonged coma patients with diffuse axonal injury assessed by somatosensory evoked potential

    Institute of Scientific and Technical Information of China (English)

    Xiujue Zheng; Mantao Chen; Jingqi Li; Fei Cao

    2013-01-01

    A total of 43 prolonged coma patients with diffuse axonal injury received the somatosensory evoked potential examination one month after injury in the First Affiliated Hospital, School of Medicine, Zhejiang University in China. Somatosensory evoked potentials were graded as normal, abnormal or absent (grades I–III) according to N20 amplitude and central conduction time. The outcome in patients with grade III somatosensory evoked potential was in each case unfavorable. The prognostic accuracy of grade III somatosensory evoked potential for unfavorable and non-awakening outcome was 100% and 80%, respectively. The prognostic accuracy of grade I somatosensory evoked potential for favorable and wakening outcome was 86% and 100%, respectively. These results suggest that somatosensory evoked potential grade is closely correlated with coma severity and degree of recovery. Somatosensory evoked potential is a valuable diagnostic tool to assess prognosis in prolonged coma patients with diffuse axonal injury.

  9. An evoked potential mapping of transcallosal projections in the cat

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    A. Cukiert

    1989-03-01

    Full Text Available In ten adult cats anesthetized with ketamine hydrochloride the neocortex was exposed and rectangular pulses (1msec, 0.5 Hz and variable intensity were applied to discrete points of one side and transcallosal evoked potentials were recorded from the other. The stimulation and recording positions were determined on a cartesian map of most of the exposable neocortical areas and the potentials were analysed as to their components, voltage and latency. Passive spread and electrotonic potentials and the effects of increasing frequency were also analysed. The results showed large transcallosal potentials in some areas and an increase of potentials in the caudorostral direction, attaining the highest values in anteromedial areas of the suprasylvian gyrus. Confirming anatomical studies, a few silent spots were found in the motor and somesthetic cortex and in restricted posterior regions of the visual cortex, where small or zero voltages occurred. While causing weak contralateral potentials, stimulation of some posterior sites provoked high voltage potentials in anterior regions of the side being stimulated and in the corresponding area of the opposite site. These posterior sites are. poorly interconnected by the corpus callosum. The L-shaped indirect connection described in this work may be involved in some types of epilepsy and may explain the effectiveness of partial callosotomy in their treatment.

  10. SOMATOSENSORY EVOKED POTENTIALS IN DIABETES MELLITUS TYPE - 2

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    Rekha

    2015-10-01

    Full Text Available Diabetes mellitus is the most common metabolic disorder affecting majority of population. It is estimated that over 400 million people throughout the world have diabetes. It has progressed to be a pandemic from an epidemic causing morbidity and mortality in the population. Among the many complications of diabetes, diabetic neuropathies contribute majorly to the morbidity associated with the disease. Axonal conduction is affected by elevated levels of protein kinase c causing neuronal ischemia; decreased ce llular myoinositol affecting sodium potassium ATPase pump leads to decreased nerve conduction; Somatosensory E voked P otentials (SSEPs reflect the activity of somatosensory pathways mediated through the dorsal columns of the spinal cord and the specific so matosensory cortex. Recording of Somatosensory Evoked Potentials in diabetics is done to assess the sensory involvement of spinal cord. Presence of SEPs provides clear evidence for axonal continuity and by using different stimulation sites, the rate of reg eneration can be determined. Both onset and peak latencies of all SEP components are prolonged in patients with diabetes. Present study is done to compare somatosensory evoked potentials in diabetics and normal subjects. MATERIALS AND METHOD S: The present study was undertaken at the Upgraded Department of Physiology, Osmania Medical College, Koti, Hyderabad. The study was conducted on subjects, both male and female in the age group of 45 to 55 years, suffering from type II diabetes excluding other neurologi cal disorders. Non - invasive method of estimation of nerve conduction studies using SFEMG/EP — Electromyography or evoked potential system (Nicolet systems — USA using surface electrodes with automated computerized monitor attached with printer is used. RESUL TS : ANOVA showed statistically significant N9 latency (right & left sides. Latencies of all the components of SSEPs were more significant than amplitudes in Diabetic

  11. Visual evoked potentials in neuromyelitis optica and its spectrum disorders.

    Science.gov (United States)

    Ringelstein, Marius; Kleiter, Ingo; Ayzenberg, Ilya; Borisow, Nadja; Paul, Friedemann; Ruprecht, Klemens; Kraemer, Markus; Cohn, Eva; Wildemann, Brigitte; Jarius, Sven; Hartung, Hans-Peter; Aktas, Orhan; Albrecht, Philipp

    2014-04-01

    Optic neuritis (ON) is a key feature of neuromyelitis optica (NMO). Recently, NMO patients of predominantly Afro-Brazilian origin were evaluated by visual evoked potentials (VEPs) and showed marked amplitude reductions. Here, we analyzed VEPs in a predominantly Caucasian cohort, consisting of 43 patients with definite NMO, 18 with anti-aquaporin (AQP) 4 antibody-seropositive NMO spectrum disorders and 61 matched healthy controls. We found reduced amplitudes in only 12.3%, prolonged latencies in 41.9% and a lack of response in 14.0% of NMO eyes. Delayed P100 latencies in eyes without prior ON suggested this was a subclinical affection. The data indicate heterogenous patterns in NMO, warranting further investigation.

  12. Vestibular myogenic and acoustical brainstem evoked potentials in neurological practice

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    O. S. Korepina

    2012-01-01

    Full Text Available Along with the inspection of acoustical cortex and brainstem EP in neurologic, otoneurologic and audiologic practice recently start to use so-called vestibular evoked myogenic potentials (VEMP. It is shown, that at ear stimulation by a loud sound and record of sterno-cleidomastoid contraction is possible to estimate function of the inferior vestibular nerve and vestibulospinal pathways, a sacculo-cervical reflex. In article some methodical and clinical questions of application of these kinds are presented. Combine research acoustic brainstem EP and VEMP allows to confirm effectively lesions of acoustical and vestibular ways at brainstem. The conclusion becomes, that this kind of inspection is important for revealing demielinisation and defeats in vestibulospinal tract, that quite often happens at MS, and at estimation of efficiency of treatment

  13. Visual evoked potentials in children prenatally exposed to methylmercury

    DEFF Research Database (Denmark)

    Yorifuji, Takashi; Murata, Katsuyuki; Bjerve, Kristian S;

    2013-01-01

    Prenatal exposure to methylmercury can cause both neurobehavioral deficits and neurophysiological changes. However, evidence of neurotoxic effects within the visual nervous system is inconsistent, possibly due to incomplete statistical adjustment for beneficial nutritional factors. We evaluated...... the effect of prenatal methylmercury exposure on visual evoked potential (VEP) latencies in Faroese children with elevated prenatal methylmercury exposure. A cohort of 182 singleton term births was assembled in the Faroe Islands during 1994-1995. At age 7 years, VEP tracings were obtained from 139 cohort...... with delayed latencies for VEP peak N145. After covariate adjustment, a delay of 2.22ms (p=0.02) was seen for each doubling of the mercury concentration in maternal hair. In agreement with neuropsychological findings, the present study suggests that prenatal methylmercury exposure may have an adverse effect...

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

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    Kumar Sanjay

    2010-01-01

    Full Text Available 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.

  15. Contact heat evoked potentials using simultaneous EEG and fMRI and their correlation with evoked pain

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    Atherton Duncan

    2008-12-01

    Full Text Available Abstract Background The Contact Heat Evoked Potential Stimulator (CHEPS utilises rapidly delivered heat pulses with adjustable peak temperatures to stimulate the differential warm/heat thresholds of receptors expressed by Aδ and C fibres. The resulting evoked potentials can be recorded and measured, providing a useful clinical tool for the study of thermal and nociceptive pathways. Concurrent recording of contact heat evoked potentials using electroencephalogram (EEG and functional magnetic resonance imaging (fMRI has not previously been reported with CHEPS. Developing simultaneous EEG and fMRI with CHEPS is highly desirable, as it provides an opportunity to exploit the high temporal resolution of EEG and the high spatial resolution of fMRI to study the reaction of the human brain to thermal and nociceptive stimuli. Methods In this study we have recorded evoked potentials stimulated by 51°C contact heat pulses from CHEPS using EEG, under normal conditions (baseline, and during continuous and simultaneous acquisition of fMRI images in ten healthy volunteers, during two sessions. The pain evoked by CHEPS was recorded on a Visual Analogue Scale (VAS. Results Analysis of EEG data revealed that the latencies and amplitudes of evoked potentials recorded during continuous fMRI did not differ significantly from baseline recordings. fMRI results were consistent with previous thermal pain studies, and showed Blood Oxygen Level Dependent (BOLD changes in the insula, post-central gyrus, supplementary motor area (SMA, middle cingulate cortex and pre-central gyrus. There was a significant positive correlation between the evoked potential amplitude (EEG and the psychophysical perception of pain on the VAS. Conclusion The results of this study demonstrate the feasibility of recording contact heat evoked potentials with EEG during continuous and simultaneous fMRI. The combined use of the two methods can lead to identification of distinct patterns of brain

  16. BRAIN DYSFUNCTION OF PATIENTS WITH QIGONG INDUCED MENTAL DISORDER REVEALED BY EVOKED POTENTIALS RECORDING

    Institute of Scientific and Technical Information of China (English)

    LU Yingzhi; ZONG Wenbin; CHEN Xingshi

    2003-01-01

    Objective: In order to investigate the brain function of patients with Qigong induced mental disorder (QIMD), this study was carried out. Methods: Four kinds of evoked potentials, including contingent negative variation (CNV), auditory evoked potentials (AEP), visual evoked potentials (VEP), and somatosensory evoked potentials (SEP), were recorded from 12 patients with Qigong induced mental disorder.Comparison of their evoked potentials with the data from some normal controls was made. Results: The results revealed that there were 3 kinds of abnormal changes in evoked potentials of patients with QIMD that is latency prolongation, amplitude increase and amplitude decrease, as compared with normal controls. Conclusion: Brain dysfunction of patients with QIMD was confirmed. Its biological mechanism needs further studying.

  17. Evoked potential correlates of intelligence: some problems with Hendrickson's string measure of evoked potential complexity and error theory of intelligence.

    Science.gov (United States)

    Vetterli, C F; Furedy, J J

    1985-07-01

    The string measure of evoked potential (EP) complexity is based on a new error theory of intelligence, which differs from the older speed-based formulations which focus on EP latency rather than complexity. In this note we first raise a methodological problem of arbitrariness with respect to one version of the string measure. We then provide a comparative empirical assessment of EP-IQ correlations with respect to a revised string measure (which does not suffer from the methodological problem), a latency measure, and another measure of EP complexity: average voltage. This assessment indicates that the string measure, in particular, yields quite disorderly results, and that, in general, the results favor the speed over the error formulation.

  18. Long Latency Auditory Evoked Potential in Term and Premature Infants

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    Didoné, Dayane Domeneghini

    2014-01-01

    Full Text Available Introduction The research in long latency auditory evokes potentials (LLAEP in newborns is recent because of the cortical structure maturation, but studies note that these potentials may be evidenced at this age and could be considered as indicators of cognitive development. Purpose To research the exogenous potentials in term and premature infants during their first month of life. Materials and Methods The sample consisted of 25 newborns, 15 term and 10 premature infants. The infants with gestational age under 37 weeks were considered premature. To evaluate the cortical potentials, the infants remained in natural sleep. The LLAEPs were researched binaurally, through insertion earphones, with frequent /ba/ and rare /ga/ speech stimuli in the intensity of 80 dB HL (decibel hearing level. The frequent stimuli presented a total of 80% of the presentations, and the rare, 20%. The data were statistically analyzed. Results The average gestational age of the term infants was 38.9 weeks (± 1.3 and for the premature group, 33.9 weeks (± 1.6. It was possible to observe only the potentials P1 and N1 in both groups, but there was no statistically significant difference for the latencies of the components P1 and N1 (p > 0.05 between the groups. Conclusion It was possible to observe the exogenous components P1 and N1 of the cortical potentials in both term and preterm newborns of no more than 1 month of age. However, there was no difference between the groups.

  19. Vestibular evoked myogenic potentials (VEMPs) in central neurological disorders.

    Science.gov (United States)

    Venhovens, J; Meulstee, J; Verhagen, W I M

    2016-01-01

    Several types of acoustic stimulation (i.e. tone bursts or clicks), bone-conducted vibration, forehead taps, and galvanic stimulation elicit myogenic potentials. These can be recorded in cervical and ocular muscles, the so called vestibular evoked myogenic potentials (VEMPs). The cervical VEMP (cVEMP) resembles the vestibulo-collic reflex and the responses can be recorded from the ipsilateral sternocleidomastoid muscle. The ocular VEMP resembles the vestibulo-ocular reflex and can be recorded from extra-ocular muscles by a surface electrode beneath the contralateral infraorbital margin. Initially, the literature concerning VEMPs was limited to peripheral vestibular disorders, however, the field of VEMP testing is rapidly expanding, with an increasing focus on central neurological disorders. The current literature concerning VEMP abnormalities in central neurological disorders is critically reviewed, especially regarding the methodological aspects in relation to quality as well as the clinical interpretation of the VEMP results. Suggestions for further research are proposed as well as some clinically useful indications. PMID:25649969

  20. Vestibular evoked myogenic potentials in patients with ankylosing spondylitis.

    Science.gov (United States)

    Özgür, Abdulkadir; Serdaroğlu Beyazal, Münevver; Terzi, Suat; Coşkun, Zerrin Özergin; Dursun, Engin

    2016-10-01

    Ankylosing spondylitis (AS) is a chronic systemic inflammatory disease with unknown etiology. Although sacroiliac joint involvement is the classic sign along with the formed immune mediators, it may result in immune-mediated inner ear disease and may cause damage to the audiovestibular system. Vestibular evoked myogenic potentials (VEMP) is a clinical reflex test used in the diagnosis of vestibular diseases and is performed by recording and evaluating the muscle potentials resulting from the stimulation of the vestibular system with different stimuli. The aim of this study is to evaluate the cervical VEMP test results in AS patients without vestibular symptoms. Thirty-three patients with AS and a control group of 30 healthy volunteers with similar demographic characteristics were evaluated in the study. VEMP wave latency, P13-N23 wave amplitude, and VEMP asymmetry ratio (VAR) values were compared between the groups. The relationship between clinical and laboratory findings of the AS patients and VEMP data were also investigated. Compared with healthy people, this study shows the response rate of patients with ankylosing spondylitis was reduced in the VEMP test, and P13-N23 wave amplitude showed a decrease in AS patients who had VEMP response (p ankylosing spondylitis. The data obtained from this study suggest that AS may lead to decreased sensitivity of the vestibular system.

  1. Subclinical hepatic encephalopathy: the diagnostic value of evoked potentials.

    Science.gov (United States)

    Kullmann, F; Hollerbach, S; Holstege, A; Schölmerich, J

    1995-01-01

    Brainstem auditory (BAEPs) and somatosensory evoked potentials (SEPs) have been shown to be useful in detecting brainstem or cortical dysfunction in neurological diseases and in combination with other methods to diagnose brain death (37,38). These neurophysiological methods are simple and easy to perform. BAEPs and SEPs can even be easily recorded in intensive care units and guarantee a standardized examination. Moreover, these methods require no extensive patient cooperation and are not heavily influenced by learning effects. The role of BAEPs in the evaluation and diagnosis of hepatic encephalopathy is not clear. BAEPs are obviously strongly influenced by the etiology of liver disease and are normal in viral hepatitis, but prolonged in alcoholic liver disease, Wilson's disease or in hepatic coma (8,12). Unfortunately, BAEPs were not compared to psychometric tests. There was no clear-cut differentiation between various hepatic encephalopathy-gradings. At present, the use of BAEPs in the detection of subclinical hepatic encephalopathy cannot be recommended, whereas in comatose patients BAEPs can be useful as a prognostic marker and for follow-up examinations (12). Recently, Pozessere et al. (12) examined 13 comatose patients with advanced coma stages (Glasgow coma scale 5-10) and recorded unspecific changes in their EEG tracings. In all cases of hepatic coma and in one intoxicated patient they found prolongation of interpeak latencies. In addition, in this small study the interpeak latencies correlated well with the clinical outcome of the patients. Only two studies were performed using SEPs to detect neurophysiological alterations in hepatic encephalopathy (32,33). The design as well as the results of these studies are quite different. Despite the small number of patients (n = 10), the prolongation of late components in 50% of patients with hepatic encephalopathy stage 0 could be a promising result (32). The value of SEPs in detecting subclinical hepatic

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

    OpenAIRE

    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 eliciti...

  3. Analysis of brain-stem auditory evoked potential and visual evoked potential in patients with Parkinson disease

    Institute of Scientific and Technical Information of China (English)

    Qiaorong Deng; Jianzhong Deng; Yanmin Zhao; Xiaohai Yan; Pin Chen

    2006-01-01

    BACKGROUND: With the development of neuroelectrophysiology, it had been identified that all kinds of evoked potentials might reflect the functional status of corresponding pathway. Evoked potentials recruited in the re search of PD, it can be known whether other functional pathway of nervous system is impaired. OBJECTIVE: To observe whether brainstem auditory and visual passageway are impaired in patients with Parkinson disease (PD), and compare with non-PD patients concurrently. DESIGN: A non-randomized concurrent controlled observation. SETTINGS: Henan Provincial Tumor Hospital; Anyang District Hospital. PARTICIPANTS: Thirty-two cases of PD outpatients and inpatients, who registered in the Department of Neurology, Anyang District Hospital from October 1997 to February 2006, were enrolled as the PD group, including 20 males and 12 females, aged 50-72 years old. Inclusive criteria: In accordance with the diagnostic criteria of PD recommended by the dyskinesia and PD group of neurology branch of Chinese Medical Association. Patients with diseases that could cause Parkinson syndrome were excluded by CT scanning or MRI examination. Meanwhile, 30 cases with non-neurological disease were selected from the Department of Internal Medicine of our hospital as the control group, including 19 males and 11 females, aged 45-70 years old. Including criteria: Without history of neurological disease or psychiatric disease; showing normal image on CT. And PD, Parkinson syndrome and Parkinsonism-plus were excluded by professional neurologist. All the patients were informed and agreed with the examination and clinical observation. METHODS: The electrophysiological examination and clinical observation of the PD patients and controls were conducted. The Reporter type 4-channel evoked potential machine (Italy) was used to check brain-stem auditory evoked potential (BAEP) and visual evoked potential (VEP). Why to be examined was explained to test taker. BAEP recording electrode was plac

  4. Vestibular evoked myogenic potential in sudden sensorineural hearing loss

    Directory of Open Access Journals (Sweden)

    Feroze Kancharu Khan

    2013-01-01

    Full Text Available Aim and Objective: To investigate saccular damage in patients with sudden sensorineural hearing loss (SSNHL with or without vertigo and to evaluate the saccular damage according to the hearing loss and presence or absence of vertigo. Materials and Methods: All tests done in this study were performed in the audio vestibular unit of ENT department from September 2009 to November 2010. Statistical Analysis Used: The association between the severity of hearing loss and changes in the vestibular evoked myogenic potential (VEMP recordings were assessed using descriptive statistics. The pattern of VEMP in different diseases and also the behavior of VEMP in presence or absence of vertigo were evaluated using SPSS 15. Results: Among 27 patients there were 11 cases of idiopathic SSNHL. Out of nine unaffected ears, 88% had normal and 12% had absent VEMP. Whereas out of 13 affected ears, only 53.9% had normal VEMP. Among all the 54 ears, 17 ears had normal hearing. In this group 76.47% had normal VEMP. The group with hearing loss > 90 dB had 61.53% absent VEMP. Conclusions: In patients with unilateral SSNHL, there was a tendency for the affected ear to have absent VEMP indicating the saccular involvement. The extent of saccular damage did not correspond to the amount of hearing loss or presence or absence of vertigo.

  5. ISCEV standard for clinical visual evoked potentials: (2016 update).

    Science.gov (United States)

    Odom, J Vernon; Bach, Michael; Brigell, Mitchell; Holder, Graham E; McCulloch, Daphne L; Mizota, Atsushi; Tormene, Alma Patrizia

    2016-08-01

    Visual evoked potentials (VEPs) can provide important diagnostic information regarding the functional integrity of the visual system. This document updates the ISCEV standard for clinical VEP testing and supersedes the 2009 standard. The main changes in this revision are the acknowledgment that pattern stimuli can be produced using a variety of technologies with an emphasis on the need for manufacturers to ensure that there is no luminance change during pattern reversal or pattern onset/offset. The document is also edited to bring the VEP standard into closer harmony with other ISCEV standards. The ISCEV standard VEP is based on a subset of stimulus and recording conditions that provide core clinical information and can be performed by most clinical electrophysiology laboratories throughout the world. These are: (1) Pattern-reversal VEPs elicited by checkerboard stimuli with large 1 degree (°) and small 0.25° checks. (2) Pattern onset/offset VEPs elicited by checkerboard stimuli with large 1° and small 0.25° checks. (3) Flash VEPs elicited by a flash (brief luminance increment) which subtends a visual field of at least 20°. The ISCEV standard VEP protocols are defined for a single recording channel with a midline occipital active electrode. These protocols are intended for assessment of the eye and/or optic nerves anterior to the optic chiasm. Extended, multi-channel protocols are required to evaluate postchiasmal lesions. PMID:27443562

  6. Alterations in oropharyngeal sensory evoked potentials (PSEP) with Parkinson's disease.

    Science.gov (United States)

    Pitts, Teresa; Hegland, Karen Wheeler; Sapienza, Christine M; Bolser, Donald C; Davenport, Paul W

    2016-07-15

    Movement of a food bolus from the oral cavity into the oropharynx activates pharyngeal sensory mechanoreceptors. Using electroencephalography, somatosensory cortical-evoked potentials resulting from oropharyngeal mechanical stimulation (PSEP) have been studied in young healthy individuals. However, limited information is known about changes in processing of oropharyngeal afferent signals with Parkinson's disease (PD). To determine if sensory changes occurred with a mechanical stimulus (air-puff) to the oropharynx, two stimuli (S1-first; S2-s) were delivered 500ms apart. Seven healthy older adults (HOA; 3 male and 4 female; 72.2±6.9 years of age), and thirteen persons diagnosed with idiopathic Parkinson's disease (PD; 11 male and 2 female; 67.2±8.9 years of age) participated. Results demonstrated PSEP P1, N1, and P2 component peaks were identified in all participants, and the N2 peak was present in 17/20 participants. Additionally, the PD participants had a decreased N2 latency and gated the P1, P2, and N2 responses (S2/S1 under 0.6). Compared to the HOAs, the PD participants had greater evidence of gating the P1 and N2 component peaks. These results suggest that persons with PD experience changes in sensory processing of mechanical stimulation of the pharynx to a greater degree than age-matched controls. In conclusion, the altered processing of sensory feedback from the pharynx may contribute to disordered swallow in patients with PD. PMID:27090350

  7. Source localisation of visual evoked potentials in congenitally deaf individuals.

    Science.gov (United States)

    Hauthal, Nadine; Thorne, Jeremy D; Debener, Stefan; Sandmann, Pascale

    2014-05-01

    Previous studies have suggested that individuals deprived of auditory input can compensate with specific superior abilities in the remaining sensory modalities. To better understand the neural basis of deafness-induced changes, the present study used electroencephalography to examine visual functions and cross-modal reorganization of the auditory cortex in deaf individuals. Congenitally deaf participants and hearing controls were presented with reversing chequerboard stimuli that were systematically modulated in luminance ratio. The two groups of participants showed similar modulation of visual evoked potential (VEP) amplitudes (N85, P110) and latencies (P110) as a function of luminance ratio. Analysis of VEPs revealed faster neural processing in deaf participants compared with hearing controls at early stages of cortical visual processing (N85). Deaf participants also showed higher amplitudes (P110) than hearing participants. In contrast to our expectations, the results from VEP source analysis revealed no clear evidence for cross-modal reorganization in the auditory cortex of deaf participants. However, deaf participants tended to show higher activation in posterior parietal cortex (PPC). Moreover, modulation of PPC responses as a function of luminance was also stronger in deaf than in hearing participants. Taken together, these findings are an indication of more efficient neural processing of visual information in the deaf, which may relate to functional changes, in particular in multisensory parietal cortex, as a consequence of early auditory deprivation. PMID:24337445

  8. Transdiagnostic psychiatric symptoms related to visual evoked potential abnormalities.

    Science.gov (United States)

    Bedwell, Jeffrey S; Butler, Pamela D; Chan, Chi C; Trachik, Benjamin J

    2015-12-15

    Visual processing abnormalities have been reported across a range of psychotic and mood disorders, but are typically examined within a particular disorder. The current study used a novel transdiagnostic approach to examine diagnostic classes, clinician-rated current symptoms, and self-reported personality traits in relation to visual processing abnormalities. We examined transient visual-evoked potentials (VEPs) from 48 adults (56% female), representing a wide range of psychotic and mood disorders, as well as individuals with no history of psychiatric disorder. Stimuli were low contrast check arrays presented on green and red backgrounds. Pairwise comparisons between individuals with schizophrenia-spectrum disorders (SSD), chronic mood disorders (CMD), and nonpsychiatric controls (NC) revealed no overall differences for either P1 or N1 amplitude. However, there was a significant interaction with the color background in which the NC group showed a significant increase in P1 amplitude to the red, vs. green, background, while the SSD group showed no change. This was related to an increase in social anhedonia and general negative symptoms. Stepwise regressions across the entire sample revealed that individuals with greater apathy and/or eccentric behavior had a reduced P1 amplitude. These relationships provide clues for uncovering the underlying causal pathology for these transdiagnostic symptoms. PMID:26412383

  9. A Subspace Method for Dynamical Estimation of Evoked Potentials

    Directory of Open Access Journals (Sweden)

    Stefanos D. Georgiadis

    2007-01-01

    Full Text Available It is a challenge in evoked potential (EP analysis to incorporate prior physiological knowledge for estimation. In this paper, we address the problem of single-channel trial-to-trial EP characteristics estimation. Prior information about phase-locked properties of the EPs is assesed by means of estimated signal subspace and eigenvalue decomposition. Then for those situations that dynamic fluctuations from stimulus-to-stimulus could be expected, prior information can be exploited by means of state-space modeling and recursive Bayesian mean square estimation methods (Kalman filtering and smoothing. We demonstrate that a few dominant eigenvectors of the data correlation matrix are able to model trend-like changes of some component of the EPs, and that Kalman smoother algorithm is to be preferred in terms of better tracking capabilities and mean square error reduction. We also demonstrate the effect of strong artifacts, particularly eye blinks, on the quality of the signal subspace and EP estimates by means of independent component analysis applied as a prepossessing step on the multichannel measurements.

  10. Flash visual evoked potentials in diurnal birds of prey.

    Science.gov (United States)

    Dondi, Maurizio; Biaggi, Fabio; Di Ianni, Francesco; Dodi, Pier Luigi; Quintavalla, Fausto

    2016-01-01

    The objective of this pilot study was to evaluate the feasibility of Flash Visual Evoked Potentials (FVEPs) testing in birds of prey in a clinical setting and to describe the protocol and the baseline data for normal vision in this species. FVEP recordings were obtained from 6 normal adult birds of prey: n. 2 Harris's Hawks (Parabuteo unicinctus), n. 1 Lanner Falcon (Falco biarmicus), n. 2 Gyrfalcons (Falco rusticolus) and n. 1 Saker Falcon (Falco cherrug). Before carrying out VEP tests, all animals underwent neurologic and ophthalmic routine examination. Waveforms were analysed to identify reproducible peaks from random variation of baseline. At least three positive and negative peaks were highlighted in all tracks with elevated repeatability. Measurements consisted of the absolute and relative latencies of these peaks (P1, N1, P2, N2, P3, and N3) and their peak-to-peak amplitudes. Both the peak latency and wave morphology achieved from normal animals were similar to those obtained previously in other animal species. This test can be easily and safely performed in a clinical setting in birds of prey and could be useful for an objective assessment of visual function. PMID:27547536

  11. Flash visual evoked potentials in diurnal birds of prey

    Science.gov (United States)

    Biaggi, Fabio; Di Ianni, Francesco; Dodi, Pier Luigi; Quintavalla, Fausto

    2016-01-01

    The objective of this pilot study was to evaluate the feasibility of Flash Visual Evoked Potentials (FVEPs) testing in birds of prey in a clinical setting and to describe the protocol and the baseline data for normal vision in this species. FVEP recordings were obtained from 6 normal adult birds of prey: n. 2 Harris’s Hawks (Parabuteo unicinctus), n. 1 Lanner Falcon (Falco biarmicus), n. 2 Gyrfalcons (Falco rusticolus) and n. 1 Saker Falcon (Falco cherrug). Before carrying out VEP tests, all animals underwent neurologic and ophthalmic routine examination. Waveforms were analysed to identify reproducible peaks from random variation of baseline. At least three positive and negative peaks were highlighted in all tracks with elevated repeatability. Measurements consisted of the absolute and relative latencies of these peaks (P1, N1, P2, N2, P3, and N3) and their peak-to-peak amplitudes. Both the peak latency and wave morphology achieved from normal animals were similar to those obtained previously in other animal species. This test can be easily and safely performed in a clinical setting in birds of prey and could be useful for an objective assessment of visual function. PMID:27547536

  12. Single-trial detection for intraoperative somatosensory evoked potentials monitoring.

    Science.gov (United States)

    Hu, L; Zhang, Z G; Liu, H T; Luk, K D K; Hu, Y

    2015-12-01

    Abnormalities of somatosensory evoked potentials (SEPs) provide effective evidence for impairment of the somatosensory system, so that SEPs have been widely used in both clinical diagnosis and intraoperative neurophysiological monitoring. However, due to their low signal-to-noise ratio (SNR), SEPs are generally measured using ensemble averaging across hundreds of trials, thus unavoidably producing a tardiness of SEPs to the potential damages caused by surgical maneuvers and a loss of dynamical information of cortical processing related to somatosensory inputs. Here, we aimed to enhance the SNR of single-trial SEPs using Kalman filtering and time-frequency multiple linear regression (TF-MLR) and measure their single-trial parameters, both in the time domain and in the time-frequency domain. We first showed that, Kalman filtering and TF-MLR can effectively capture the single-trial SEP responses and provide accurate estimates of single-trial SEP parameters in the time domain and time-frequency domain, respectively. Furthermore, we identified significant correlations between the stimulus intensity and a set of indicative single-trial SEP parameters, including the correlation coefficient (between each single-trial SEPs and their average), P37 amplitude, N45 amplitude, P37-N45 amplitude, and phase value (at the zero-crossing points between P37 and N45). Finally, based on each indicative single-trial SEP parameter, we investigated the minimum number of trials required on a single-trial basis to suggest the existence of SEP responses, thus providing important information for fast SEP extraction in intraoperative monitoring. PMID:26557929

  13. Brainstem auditory-evoked potential in Boxer dogs

    Directory of Open Access Journals (Sweden)

    Mariana Isa Poci Palumbo

    2014-10-01

    Full Text Available Brainstem auditory-evoked potential (BAEP has been widely used for different purposes in veterinary practice and is commonly used to identify inherited deafness and presbycusis. In this study, 43 Boxer dogs were evaluated using the BAEP. Deafness was diagnosed in 3 dogs (2 bilateral and 1 unilateral allowing the remaining 40 Boxers to be included for normative data analysis including an evaluation on the influence of age on the BAEP. The animals were divided into 2 groups of 20 Boxers each based on age. The mean age was 4.54 years (range, 1-8 in group I, and 9.83 years (range, 8.5-12 in group II. The mean latency for I, III, and V waves were 1.14 (±0.07, 2.64 (±0.11, and 3.48 (±0.10 ms in group I, and 1.20 (±0.12, 2.73 (±0.15, and 3.58 (±0.22 ms in group II, respectively. The mean inter-peak latencies for the I-III, III-V and I-V intervals were 1.50 (±0.15, 0.84 (±0.15, and 2.34 (±0.11 ms in group I, and 1.53 (±0.16, 0.85 (±0.15, and 2.38 (±0.19 ms in group II, respectively. Latencies of waves I and III were significant different between group I and II. For the I-III, III-V and I-V intervals, no significant differences were observed between the 2 groups. As far as we know, this is the first normative study of BAEP obtained from Boxer dogs.

  14. EVALUATION OF BRAINSTEM AUDITORY EVOKED POTENTIAL IN MIGRAINE PATIENT

    Directory of Open Access Journals (Sweden)

    Sowmiya R, Vinodha R

    2015-10-01

    Full Text Available Background: Migraine is worldwide common, chronic, Neurovascular disorder, characterized by attacks of severe headache and an Aura involving neurologic symptoms. Its pathogenesis was incompletely understood whether of cortical or brainstem origin. Aim: The present study was undertaken to investigate brainstem auditory functions in Migraine patients. Materials and Methods: The subjects were recruited based on International Headache Society classification for Migraine. Subjects with episodes of headache for at least 2yrs, 2 attacks per month in last quarter year were included in the study. Forty subjects (16 Migraine with Aura & 24 cases – Migraine without aura & forty age / sex matched controls were selected. Brainstem auditory evoked potential was recorded using 4-Channel polygraph (Neuro perfect plus. Electrodes were placed according to 10 – 20 electrode placement system. Auditory stimulus in the form of click sound is delivered through the headphones. Clicks were delivered at a rate of 8-10 /sec. The intensity of the stimulus is set at 30db. About 100 averages were recorded. BAEP waveforms – Wave I, III & V latencies and the interpeak latencies were measured. The results were analysed statistically using student‘t’ test. Results: BAEP recording shows significant prolongation in latencies of Wave I, III & V and the Interpeak latency (IPL I-III, III-V & I-V in Migraine with aura. In Migraine without aura, there was significant prolongation of Wave I, III & V and III-V & I-VIPL (P<0.05. Conclusion: Prolongation suggests that there is involvement of brainstem structures in Migraine, thus BAEP can be used as an effective tool in evaluation of Migraine.

  15. Ocular vestibular evoked myogenic potentials in normal-hearing adults

    Directory of Open Access Journals (Sweden)

    Mohammad Kamali

    2012-06-01

    Full Text Available Background and Aim: Ocular vestibular-evoked myogenic potential (oVEMP is a novel vestibular function test. This short-latency response can be recorded through contracting extraocular muscles by high-intensity acoustic stimulation and can be used to evaluate contralateral ocular-vestibular reflex. The aim of this study was to record and compare the amplitude, latency, asymmetry ratio and occurrence percentage of oVEMP (n10 and cervical VEMP (p13 responses in a group of normal adult subjects.Methods: We carried out a cross-sectional study on 20 adult subjects' mean age 22.18 years, SD=2.19 with normal hearing sensitivity and no history of vestibular diseases. oVEMP and cVEMP responses in both ears were recorded using air conducted stimuli 500 Hz short tone burst, 95 dB nHL via insert earphone and compared.Results: cVEMP was recorded in all subjects but oVEMP was absent in two subjects. Mean amplitude and latency were 140.77 μv and 15.56 ms in p13; and 3.18 μv and 9.32 ms in n10. There were statistically significant differences between p13 and n10 amplitudes (p<0.001.Conclusion: This study showed that occurrence percentage and amplitude of oVEMP were less than those of cVEMP. Since these two tests originate from different sections of vestibular nerve, we can consider them as parallel vestibular function tests and utilize them for evaluation of vestibular disorders.

  16. The effect of changes in perilymphatic K+ on the vestibular evoked potential in the guinea pig

    NARCIS (Netherlands)

    Kingma, C. M.; Wit, H. P.

    2010-01-01

    To investigate the effect on the functioning of the vestibular system of a rupture of Reissner's membrane, artificial endolymph was injected in scala media of ten guinea pigs and vestibular evoked potentials (VsEPs), evoked by vertical acceleration pulses, were measured. Directly after injection of

  17. High frequency bone conduction auditory evoked potentials in the guinea pig: Assessing cochlear injury after ossicular chain manipulation.

    Science.gov (United States)

    Bergin, M J; Bird, P A; Vlajkovic, S M; Thorne, P R

    2015-12-01

    Permanent high frequency (>4 kHz) sensorineural hearing loss following middle ear surgery occurs in up to 25% of patients. The aetiology of this loss is poorly understood and may involve transmission of supra-physiological forces down the ossicular chain to the cochlea. Investigating the mechanisms of this injury using animal models is challenging, as evaluating cochlear function with evoked potentials is confounded when ossicular manipulation disrupts the normal air conduction (AC) pathway. Bone conduction (BC) using clinical bone vibrators in small animals is limited by poor transducer output at high frequencies sensitive to trauma. The objectives of the present study were firstly to evaluate a novel high frequency bone conduction transducer with evoked auditory potentials in a guinea pig model, and secondly to use this model to investigate the impact of middle ear surgical manipulation on cochlear function. We modified a magnetostrictive device as a high frequency BC transducer and evaluated its performance by comparison with a calibrated AC transducer at frequencies up to 32 kHz using the auditory brainstem response (ABR), compound action potential (CAP) and summating potential (SP). To mimic a middle ear traumatising stimulus, a rotating bur was brought in to contact with the incudomalleal complex and the effect on evoked cochlear potentials was observed. BC-evoked potentials followed the same input-output function pattern as AC potentials for all ABR frequencies. Deterioration in CAP and SP thresholds was observed after ossicular manipulation. It is possible to use high frequency BC to evoke responses from the injury sensitive basal region of the cochlea and so not rely on AC with the potential confounder of conductive hearing loss. Ongoing research explores how these findings evolve over time, and ways in which injury may be reduced and the cochlea protected during middle ear surgery.

  18. High frequency bone conduction auditory evoked potentials in the guinea pig: Assessing cochlear injury after ossicular chain manipulation.

    Science.gov (United States)

    Bergin, M J; Bird, P A; Vlajkovic, S M; Thorne, P R

    2015-12-01

    Permanent high frequency (>4 kHz) sensorineural hearing loss following middle ear surgery occurs in up to 25% of patients. The aetiology of this loss is poorly understood and may involve transmission of supra-physiological forces down the ossicular chain to the cochlea. Investigating the mechanisms of this injury using animal models is challenging, as evaluating cochlear function with evoked potentials is confounded when ossicular manipulation disrupts the normal air conduction (AC) pathway. Bone conduction (BC) using clinical bone vibrators in small animals is limited by poor transducer output at high frequencies sensitive to trauma. The objectives of the present study were firstly to evaluate a novel high frequency bone conduction transducer with evoked auditory potentials in a guinea pig model, and secondly to use this model to investigate the impact of middle ear surgical manipulation on cochlear function. We modified a magnetostrictive device as a high frequency BC transducer and evaluated its performance by comparison with a calibrated AC transducer at frequencies up to 32 kHz using the auditory brainstem response (ABR), compound action potential (CAP) and summating potential (SP). To mimic a middle ear traumatising stimulus, a rotating bur was brought in to contact with the incudomalleal complex and the effect on evoked cochlear potentials was observed. BC-evoked potentials followed the same input-output function pattern as AC potentials for all ABR frequencies. Deterioration in CAP and SP thresholds was observed after ossicular manipulation. It is possible to use high frequency BC to evoke responses from the injury sensitive basal region of the cochlea and so not rely on AC with the potential confounder of conductive hearing loss. Ongoing research explores how these findings evolve over time, and ways in which injury may be reduced and the cochlea protected during middle ear surgery. PMID:26493491

  19. Comparison of sensitivity of magnetic resonance imaging and evoked potentials in the detection of brainstem involvement in multiple sclerosis

    International Nuclear Information System (INIS)

    A comparison was made of the sensitivity of magnetic resonance imaging and the combined use of Brainstem Auditory Evoked Potential and Median Somatosensory Evoked Potential in the detection of brainstem dysfunction in 54 multiple sclerosis patients. 10 refs.; 2 tabs

  20. Contact Heat Evoked Potentials (CHEPs) in Patients with Mild-Moderate Alzheimer's Disease and Matched Control

    DEFF Research Database (Denmark)

    Jensen-Dahm, Christina; Madsen, Caspar Skau; Waldemar, Gunhild;

    2016-01-01

    using somatosensory evoked potentials and contact heat evoked potentials in patients with Alzheimer's disease and in healthy elderly controls. DESIGN: Case-control study SETTING AND SUBJECTS: Twenty outpatients with mild-moderate Alzheimer's disease and in 17 age- and gender-matched healthy controls...... threshold and heat pain threshold. Somatosensory evoked potentials, amplitude, and latency were within normal range and similar for the two groups. CONCLUSIONS: The findings suggest that the processing of non-painful and painful stimuli is preserved in patients with mild to moderate Alzheimer's disease....

  1. Short latency vestibular potentials evoked by electrical round window stimulation in the guinea pig.

    Science.gov (United States)

    Bordure, P; Desmadryl, G; Uziel, A; Sans, A

    1989-11-01

    Short-latency potentials evoked by round window electrical stimulation were recorded in guinea pig by means of vertex-pinna skin electrodes using averaging techniques. Constant current shocks of 20 microseconds or 50 microseconds (25-300 microA) were used to evoke both auditory and vestibular brain-stem potentials. Pure auditory potentials, comparable to those evoked by acoustic clicks, were obtained by 20 microseconds electrical stimuli and disappeared during an auditory masking procedure made with a continuous white noise (110 dB SPL). Short latency potentials labeled V1, V2 and V3 were obtained by 50 microseconds electrical stimuli during an auditory masking procedure. This response disappeared after specific vestibular neurectomy, whereas the auditory response evoked by acoustic clicks or by electrical stimulation remained unchanged, suggesting that these latter potentials had a vestibular origin.

  2. 大麻素CB1受体对大鼠视网膜神经节细胞诱发动作电位的作用%Activation of cannabinoid CB1 receptors modulates evoked action potentials in rat retinal ganglion cells

    Institute of Scientific and Technical Information of China (English)

    蒋淑霞; 李倩; 王霄汉; 李芳; 王中峰

    2013-01-01

    Activation of cannabinoid CB1 receptors (CB 1Rs) regulates a variety of physiological functions in the vertebrate retina through modulating various types of ion channels.The aim of the present study was to investigate the effects of this receptor on cell excitability of rat retinal ganglion cells (RGCs) in retinal slices using whole-cell patch-clamp techniques.The results showed that under current-clamped condition perfusing WIN55212-2 (WIN,5 μmol/L),a CB1R agonist,did not significantly change the spontaneous firing frequency and resting membrane potential of RGCs.In the presence of cocktail synaptic blockers,including excitatory postsynaptic receptor blockers CNQX and D-APV,and inhibitory receptor blockers bicuculline and strychnine,perfusion of WIN (5 μmol/L)hardly changed the frequencies of evoked action potentials by a series of positive current injection (from +10 to +100 pA).Phaseplane plot analysis showed that both average threshold voltage for triggering action potential and delay time to reach threshold voltage were not affected by WIN.However,WIN significantly decreased +dV/dtmax and-dV/dtmax of action potentials,suggestive of reduced rising and descending velocities of action potentials.The effects of WIN were reversed by co-application of SR141716,a CB1R selective antagonist.Moreover,WIN did not influence resting membrane potential of RGCs with synaptic inputs being blocked.These results suggest that activation of CB1Rs may regulate intrinsic excitability of rat RGCs through modulating evoked action potentials.%激活大麻素CB1受体(CB1Rs)通过调控多种离子通道,从而调节脊椎动物视网膜的功能.本文旨在利用膜片钳全细胞记录技术,在大鼠视网膜薄片上研究CB1Rs对神经节细胞兴奋性的作用.结果显示,在电流钳制状态下,灌流CB1R激动剂WIN55212-2 (WIN,5μmol/L)对神经节细胞的自发动作电位发放频率和静息膜电位均没有显著影响.在灌流液中加入CNQX,D-APV,bicuculline

  3. Quantifying interhemispheric symmetry of somatosensory evoked potentials with the intraclass correlation coefficient

    NARCIS (Netherlands)

    van de Wassenberg, Wilma J. G.; van der Hoeven, Johannes H.; Leenders, Klaus L.; Maurits, Natasha M.

    2008-01-01

    Although large intersubject variability is reported for cortical somatosensory evoked potentials (SEPs), variability between hemispheres within one subject is thought to be small. Therefore, interhemispheric comparison of SEP waveforms might be clinically useful to detect unilateral abnormalities in

  4. Magnetic stimulation of muscle evokes cerebral potentials in assessment of paraspinal muscle spasm.

    Institute of Scientific and Technical Information of China (English)

    1998-01-01

    Objectlve: To assess the muscle spasm by magnetic stimulation of muscle evokes cerebral potentials (MMSEP). Methods: Paraspinal MMSEP and function assessment was recorded in detail before and after treat-

  5. Simultaneous measurement of behavior and the somatosensory-evoked potential in a rat model

    NARCIS (Netherlands)

    Schaap, M.W.H.; Uilenreef, J.J.; Doornenbal, A.; van 't Klooster, J.; Arndt, S.S.; Hellebrekers, L.J.

    2011-01-01

    Studies have shown that specific characteristics of somatosensory evoked potentials (SEPs) reflect nociception in both animals and humans. A relationship between SEPs and the unpleasantness of noxious stimulation in rats has recently been demonstrated using Pavlovian fear conditioning, consisting of

  6. V ISUAL EVOKED POTENTIALS IN TYPE - 1 DIABETES WITHOUT RETINOPATHY: CO - RELATIONS WITH DURATION OF DIABETES

    OpenAIRE

    Sanjeev Kumar; Virendra; Tonpay; Milind; Nikhil

    2014-01-01

    20 diabetic (Type 1) patients have been studied in order to investigate the possible effects of the type 1 diabetes mellitus on the central nervous system by means of pattern shift visual evoked potentials. Patients with diabetic retinopathy , glaucoma and cataract were excluded from the study. To evaluate central optic pathways involvement in diabetics , visual evoked po tentials (VEP) , in particular the latency of positive peak (P100) , were stu...

  7. A single dose of lorazepam reduces paired-pulse suppression of median nerve evoked somatosensory evoked potentials.

    Science.gov (United States)

    Stude, Philipp; Lenz, Melanie; Höffken, Oliver; Tegenthoff, Martin; Dinse, Hubert

    2016-05-01

    Paired-pulse behaviour in the somatosensory cortex is an approach to obtain insights into cortical processing modes and to obtain markers of changes of cortical excitability attributable to learning or pathological states. Numerous studies have demonstrated suppression of the response to the stimulus that follows a first one after a short interval, but the underlying mechanisms remain elusive, although there is agreement that GABAergic mechanisms seem to play a crucial role. We therefore aimed to explore the influence of the GABAA agonist lorazepam on paired-pulse somatosensory evoked potentials (SEPs). We recorded and analysed SEPs after paired median nerve stimulation in healthy individuals before and after they had received a single dose of 2.5 mg of lorazepam as compared with a control group receiving placebo. Paired-pulse suppression was expressed as a ratio of the amplitudes of the second and the first peaks. We found that, after lorazepam application, paired-pulse suppression of the cortical N20 component remained unchanged, but suppression of the N20-P25 complex was significantly reduced, indicative of GABAergic involvement in intracortical processing. Our data suggest that lorazepam most likely enhances inhibition within the cortical network of interneurons responsible for creating paired-pulse suppression, leading to reduced inhibitory drive with a subsequently reduced amount of suppression. The results provide further evidence that GABAA -mediated mechanisms are involved in the generation of median nerve evoked paired-pulse suppression. PMID:26929110

  8. Effects of excitatory amino acid antagonists on evoked and spontaneous excitatory potentials in guinea-pig hippocampus.

    Science.gov (United States)

    Cotman, C W; Flatman, J A; Ganong, A H; Perkins, M N

    1986-09-01

    Evoked and spontaneous excitatory post-synaptic potentials (e.p.s.p.s) at the mossy fibre input to CA3 pyramidal neurones were recorded intracellularly in slices from the guinea-pig hippocampus. The effects of several amino acid antagonists on these responses were examined. L-2-amino-4-phosphonobutyrate (L-AP4), L-serine-O-phosphate (L-SOP), kynurenate, and N-(p-bromobenzoyl)piperazine-2,3-dicarboxylate (pBB-PzDA) reduced the amplitude of evoked mossy fibre e.p.s.p.s without affecting membrane potential or input resistance. Antagonism of mossy fibre spontaneous miniature e.p.s.p.s (m.e.p.s.p.s) by these compounds fell into two groups. L-AP4 and L-SOP applied at concentrations that blocked evoked e.p.s.p.s did not affect amplitude distributions of spontaneous m.e.p.s.p.s. Kynurenate and pBB-PzDA significantly affected the amplitude distributions and reduced the mean amplitude of spontaneous m.e.p.s.p.s. These results are consistent with a presynaptic site of action for L-AP4 and L-SOP and a post-synaptic site of action for kynurenate and pBB-PzDA as antagonists of e.p.s.p.s at the guinea-pig mossy fibre-CA3 pyramidal neurone synapse.

  9. Electrophysiologic studies of cervical vagus nerve stimulation in humans: II. Evoked potentials.

    Science.gov (United States)

    Hammond, E J; Uthman, B M; Reid, S A; Wilder, B J

    1992-01-01

    Evidence from studies of experimental animals indicates that electrical stimulation of the vagus nerve not only can alter the EEG but evokes activity in specific brain areas. We report effects of electrical stimulation of the vagus nerve in 9 patients with medically intractable seizures as part of a clinical trial of chronic vagal stimulation for control of epilepsy. The left vagus nerve in the neck was stimulated with a programmable implanted stimulator. Effects of stimulus amplitude, duration, and rate were studied. Noncephalic reference recording of the vagus nerve evoked potential showed some unusual properties: a scalp negative component occurred with a latency of 12 ms, very high amplitude (60 microV), and widespread scalp distribution. Field distribution studies indicated that this potential was myogenic in origin and generated in the region of the stimulating electrodes in the neck area. Chemically induced muscle paralysis confirmed this observation. Bipolar scalp recording showed several small-amplitude topographically distinct potentials occurring in 30 ms. No effect, either acute or chronic, could be detected on pattern-reversal evoked potentials, auditory brainstem evoked potentials, auditory 40-Hz potentials, or cognitive evoked potentials. PMID:1464258

  10. Prognostic value of evoked and event-related potentials in moderate to severe brain injury.

    Science.gov (United States)

    Lew, Henry L; Poole, John H; Castaneda, Annabel; Salerno, Rose Marie; Gray, Max

    2006-01-01

    Clinicians are often expected to project patients' clinical outcomes to allow effective planning for future care. This can be a challenge in patients with moderate to severe traumatic brain injury (TBI) who are often unable to participate reliably in clinical evaluations. With recent advances in computer instrumentation and signal processing, evoked potentials and event-related potentials show increasing promise as powerful tools for prognosticating the trajectory of recovery and ultimate outcome from the TBI. Short- and middle-latency evoked potentials can now effectively predict coma outcomes in patients with acute TBI. Long-latency event-related potential components hold promise in predicting recovery of higher order cognitive abilities. PMID:16915010

  11. Dynamic extraction of visual evoked potentials through spatial analysis and dipole localization.

    Science.gov (United States)

    Wang, Y; Yang, F

    1995-08-01

    The dynamic extraction of evoked potential is a problem of great interest in EEG signal processing. In this paper, a comprehensive method is presented which integrates spatial analysis and dipole localization to make full use of the spatial-temporal information contained in the multichannel stimulation records. A realistic double boundary head model is constructed through CT scans and a two-step method devised to overcome the ill-posed nature of the forward problem of EEG caused by the low conductivity of the skull. As a result, visual evoked potentials can be effectively extracted from only two consecutive records and the dynamic information of visual evoked potential thus procured. The efficiency of the presented method has been verified by means of computer simulation and a clinical experiment.

  12. Effect of body temperature on visual evoked potential delay and visual perception in multiple sclerosis.

    Science.gov (United States)

    Regan, D; Murray, T J; Silver, R

    1977-11-01

    Seven multiple sclerosis patients were cooled and four heated, but evoked potential delay changed in only five out 11 experiments. Control limits were set by cooling eight and heating four control subjects. One patient gave anomalous results in that although heating degraded perceptual delay and visual acuity, and depressed the sine wave grating MTF, double-flash resolution was improved. An explanation is proposed in terms of the pattern of axonal demyelination. The medium frequency flicker evoked potential test seems to be a less reliable means of monitoring the progress of demyelination in multiple sclerosis patients than is double-flash campimetry or perceptual delay campimetry, although in some situations the objectivity of the evoked potential test would be advantageous.

  13. Quantifying the effect of isoflurane and nitrous oxide on somatosensory-evoked potentials

    Directory of Open Access Journals (Sweden)

    Usha Devadoss

    2010-01-01

    Full Text Available Anaesthetic techniques may have a significant effect on intraoperative-evoked potentials (EP. The present study is designed to compare Propofol anaesthesia with Isoflurane (with or without nitrous oxide during intraoperative somatosensory-evoked potential (SSEP monitoring in 15 ASA Grade I and II patients undergoing surgery for intracranial tumours. SSEPs in response to median and posterior tibial nerve stimulation were recorded under four different anaesthetic conditions: 1 Propofol infusion and ventilation with air-oxygen, 2 Isoflurane, 1.0 MAC and ventilation with air-oxygen, 3 Isoflurane 1.0 MAC and ventilation with nitrous oxide-oxygen, and 4 Return to Isoflurane, 1.0 MAC and ventilation with air-oxygen. Intraoperative monitoring of somatosensory evoked potentials is best recordable using Propofol. The morphology of the EP is reproducible with Isoflurane. This effect is exaggerated when it is advisable to avoid nitrous oxide.

  14. Are somatosensory evoked potentials of the tibial nerve the most sensitive test in diagnosing multiple sclerosis?

    Directory of Open Access Journals (Sweden)

    Djuric S

    2010-01-01

    Full Text Available Background : Multiple sclerosis (MS is mostly diagnosed clinically, but the diagnosis has significantly improved through the use of brain magnetic resonance imaging (MRI, testing of cerebrospinal fluid, and multimodal evoked potentials (MEPs. Even though MRI is the superior method in diagnosing this illness, MEPs remain important because they can detect clinically silent lesions in the sensory and motor pathways of the central nervous system (CNS. Aim : The aim of the study is to test the diagnostic sensitivity of MEPs and MRI and the ratio of their sensitivity in patients with MS. Materials and Methods : The study subjects included 293 patients with MS with disease duration of two to six years: 249 patients with relapsing-remitting (RR MS and 44 with primary-progressive (PP MS. All patients were subjected to an MRI brain scan, visual evoked potentials (VEPs, median somatosensory evoked potentials (SEPs, tibial somatosensory evoked potentials (SEPs, and auditory evoked potentials (AEPs. Abnormal Findings Included : changed wave morphology, interside difference in wave amplitude, absolute and interwave latency increased by 2.5 SD as compared with the control group. The control group comprised of 35 healthy subjects. Results : In this study the most abnormal findings were tibial SEPs, median SEPs, and VEPs. Our results suggest different sensitivity of MEPs in patients suffering from different forms of MS. In RR-MS the sensitivity of tibial SEPs was statically significant (Fischer′s exact probability test as compared to other evoked potential modalities. Similarly VEPs were more sensitive as compared to AEPs. In the PP-MS, median SEPs have been found to be more sensitive than VEPs, while tibial SEPs have been found to be more sensitive than AEPs. There was no significant difference in the sensitivity of MRI and MEPs both the forms of MS. Conclusion : Tibial SEPs produce the most abnormal results and the highest sensitivity in the RR-MS. We

  15. Proprioceptive evoked potentials in man: cerebral responses to changing weight loads on the hand

    DEFF Research Database (Denmark)

    Arnfred, S; He, Chen; Eder, D;

    2000-01-01

    We studied cerebral evoked potentials on the scalp to the stimulation of the right hand from a change in weight of 400-480 g in ten subjects. Rise-time was 20g/10 ms, Inter Stimulus Interval 2s and stimulus duration was 100 ms. The cerebral activations were a double positive contralateral C3'/P70......, P190, and a single negative frontal Fz/N70 component. We conclude that a brisk change of a hand held load elicits a significant evoked potential (EP) unlike the electrical somato-sensory EP (SEP). The stimulus is perceived as applied force. For this reason we call it a proprioceptive EP (PEP...

  16. Influence of a preceding auditory stimulus on evoked potential of the succeeding stimulus

    Institute of Scientific and Technical Information of China (English)

    WANG Mingshi; LIU Zhongguo; ZHU Qiang; LIU Jin; WANG Liqun; LIU Haiying

    2004-01-01

    In the present study, we investigated the influence of the preceding auditory stimulus on the auditory-evoked potential (AEP) of the succeeding stimuli, when the human subjects were presented with a pair of auditory stimuli. We found that the evoked potential of the succeeding stimulus was inhibited completely by the preceding stimulus, as the inter-stimulus interval (ISI) was shorter than 150 ms. This influence was dependent on the ISI of two stimuli, the shorter the ISI the stronger the influence would be. The inhibitory influence of the preceding stimulus might be caused by the neural refractory effect.

  17. THE MECHANISM OF CEREBRAL EVOKED POTENTIALS BYREPETITIVE MAGNETIC STIMULATION OF GASTROCNEMIUS MUSCLE IN DUCHENNE MUSCULAR DYSTROPHY

    Institute of Scientific and Technical Information of China (English)

    管宇宙; 崔丽英; 汤晓芙; 李本红; 杜华

    2001-01-01

    Objective. To study the features and mechanism of the cerebral evoked potentials by repetitive stimulation of calf muscle in Duchenne muscular dystrophy (DMD) patients with obvious muscular dystrophy and psuedohypertrophy. Methods. Cerebral evoked potentials by stimulation of calf muscles and somatusensory evoked potentials(SEPs) by the stimulation of posterior tibial nerves at ankle were measured in 10 patients with DMD and 10 norreal controls matched with gender and age. The intensity of the magnetic stimulation was at 30% of maximal output (2. 1 Tesla, MagPro magnetic stimulator, Dantec) and the frequency was 1 Hz. The low intensity of magnet-ic stimulation was just sufficient to produce a contraction of the muscle belly underneath the coil. Recording electrode was placed at 2 cm posterior to the Cz, reference to Fpz. The latencies of N33, P38, N48 and P55 and ampli-tude (P38 - N48) were recorded. SEPs were recorded by routine methods. Results. In normal subjects, the amphtudes of cerebral evoked potentials by magnetic stimulation of calf mus-cle was 40% lower than that by electrical stimulation of the posterior tibial nerves at ankle. The latency of P38 was 2. 9 ± 2. 1 ms longer compared with electrical stimulation of the posterior tibial nerves at ankle. In 6 patients, P38 latency from magnetic stimulation was remarkably prolonged ( P < 0. 01), and in 4 patients, there was no remarkable response. SEPs evoked by electrical stimulation were normal in all of the patients. Conclusion. DMD is an available model for the study of mechanism of cerebral evoked potentials by magnetic stimulating muscle. We can conclude that the responses from magnetic stimulation were produced by muscle input. The abnormal responses in patients may relate to decreased input of muscle by stimulating dystrophic and psedohypertrophic muscle.

  18. Effect of mechanical tactile noise on amplitude of visual evoked potentials: multisensory stochastic resonance.

    Science.gov (United States)

    Méndez-Balbuena, Ignacio; Huidobro, Nayeli; Silva, Mayte; Flores, Amira; Trenado, Carlos; Quintanar, Luis; Arias-Carrión, Oscar; Kristeva, Rumyana; Manjarrez, Elias

    2015-10-01

    The present investigation documents the electrophysiological occurrence of multisensory stochastic resonance in the human visual pathway elicited by tactile noise. We define multisensory stochastic resonance of brain evoked potentials as the phenomenon in which an intermediate level of input noise of one sensory modality enhances the brain evoked response of another sensory modality. Here we examined this phenomenon in visual evoked potentials (VEPs) modulated by the addition of tactile noise. Specifically, we examined whether a particular level of mechanical Gaussian noise applied to the index finger can improve the amplitude of the VEP. We compared the amplitude of the positive P100 VEP component between zero noise (ZN), optimal noise (ON), and high mechanical noise (HN). The data disclosed an inverted U-like graph for all the subjects, thus demonstrating the occurrence of a multisensory stochastic resonance in the P100 VEP.

  19. Predictability of painful stimulation modulates the somatosensory-evoked potential in the rat.

    Directory of Open Access Journals (Sweden)

    Manon W H Schaap

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

  20. On the significance of giant somatosensory evoked potentials in cortical myoclonus.

    OpenAIRE

    Rothwell, J. C.; Obeso, J A; Marsden, C D

    1984-01-01

    Four patients with cortical myoclonus were studied. All had reflex muscle jerking and grossly enlarged somatosensory evoked responses (SEPs) following electrical stimulation of the digital nerves. In addition, three of the patients had spontaneous or action-induced myoclonus. Back-averaging the EEG from these spontaneous muscle jerks showed a large positive wave over the contralateral somatomotor cortex which preceded the jerk by about 20 ms. Administration of lisuride (0.1 mg iv) reduced the...

  1. Early visual evoked potentials are modulated by eye position in humans induced by whole body rotations

    Directory of Open Access Journals (Sweden)

    Petit Laurent

    2004-09-01

    Full Text Available Abstract Background To reach and grasp an object in space on the basis of its image cast on the retina requires different coordinate transformations that take into account gaze and limb positioning. Eye position in the orbit influences the image's conversion from retinotopic (eye-centered coordinates to an egocentric frame necessary for guiding action. Neuroimaging studies have revealed eye position-dependent activity in extrastriate visual, parietal and frontal areas that is along the visuo-motor pathway. At the earliest vision stage, the role of the primary visual area (V1 in this process remains unclear. We used an experimental design based on pattern-onset visual evoked potentials (VEP recordings to study the effect of eye position on V1 activity in humans. Results We showed that the amplitude of the initial C1 component of VEP, acknowledged to originate in V1, was modulated by the eye position. We also established that putative spontaneous small saccades related to eccentric fixation, as well as retinal disparity cannot explain the effects of changing C1 amplitude of VEP in the present study. Conclusions The present modulation of the early component of VEP suggests an eye position-dependent activity of the human primary visual area. Our findings also evidence that cortical processes combine information about the position of the stimulus on the retinae with information about the location of the eyes in their orbit as early as the stage of primary visual area.

  2. Instrumentation to record evoked potentials for closed-loop control of deep brain stimulation.

    Science.gov (United States)

    Kent, Alexander R; Grill, Warren M

    2011-01-01

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

  3. Cholinergic pairing with visual activation results in long-term enhancement of visual evoked potentials.

    Directory of Open Access Journals (Sweden)

    Jun Il Kang

    Full Text Available 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, alpha7 (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 alpha7 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.

  4. Glass pipette-carbon fiber microelectrodes for evoked potential recordings

    Directory of Open Access Journals (Sweden)

    Moraes M.F.D.

    1997-01-01

    Full Text Available Current methods for recording field potentials with tungsten electrodes make it virtually impossible to use the same recording electrode also as a lesioning electrode, for example for histological confirmation of the recorded site, because the lesioning procedure usually wears off the tungsten tip. Therefore, the electrode would have to be replaced after each lesioning procedure, which is a very high cost solution to the problem. We present here a low cost, easy to make, high quality glass pipette-carbon fiber microelectrode that shows resistive, signal/noise and electrochemical coupling advantages over tungsten electrodes. Also, currently used carbon fiber microelectrodes often show problems with electrical continuity, especially regarding electrochemical applications using a carbon-powder/resin mixture, with consequent low performance, besides the inconvenience of handling such a mixture. We propose here a new method for manufacturing glass pipette-carbon fiber microelectrodes with several advantages when recording intracerebral field potentials

  5. Event-related evoked potentials in chronic respiratory encephalopathy

    OpenAIRE

    Zaidan, Radwan

    2010-01-01

    A R Al Tahan1, R Zaidan1, S Jones2, A Husain3, A Mobeireek1, A Bahammam11Department of Medicine, 3Department of Physiology, College of Medicine, King Saud University, Riyadh, Saudi Arabia; 2Department of Neurophysiology, Institute of Neurology, London, UKBackground: Cognitive event-related potential (P300) is an index of cognitive processing time. It was found to be prolonged in dementia, renal, and hepatic encephalopathies, but was not extensively assessed in respiratory failure.Objective: T...

  6. Glass pipette-carbon fiber microelectrodes for evoked potential recordings

    OpenAIRE

    Moraes M.F.D.; Garcia-Cairasco N.

    1997-01-01

    Current methods for recording field potentials with tungsten electrodes make it virtually impossible to use the same recording electrode also as a lesioning electrode, for example for histological confirmation of the recorded site, because the lesioning procedure usually wears off the tungsten tip. Therefore, the electrode would have to be replaced after each lesioning procedure, which is a very high cost solution to the problem. We present here a low cost, easy to make, high quality glass pi...

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

    OpenAIRE

    Litscher, Gerhard

    2012-01-01

    Background and aims: Laser acupuncture is a therapeutic medical method. Innovative basic research is necessary within this fascinating area of research. This publication focuses on visual evoked potentials (VEP) elucidated by non-invasive and partially non-perceptible laser stimulation.

  8. Effect of epidural 0.25% bupivacaine on somatosensory evoked potentials to dermatomal stimulation

    DEFF Research Database (Denmark)

    Lund, C; Hansen, O B; Kehlet, H

    1989-01-01

    The effect of lumbar epidural analgesia with similar volumes (about 25 ml) of 0.25% and 0.5% bupivacaine on early (less than 0.5 seconds) somatosensory evoked potentials (SEPs) to electrical stimulation of the S1, L1, and T10 dermatomes was examined in two groups of ten patients. Level of sensory...

  9. Effects of etidocaine administered epidurally on changes in somatosensory evoked potentials after dermatomal stimulation

    DEFF Research Database (Denmark)

    Lund, C; Hansen, O B; Kehlet, H;

    1991-01-01

    The effect of lumbar epidural anesthesia with similar volumes (approximately 20 ml) of 1% and 1.5% etidocaine on early (less than 0.5 seconds) somatosensory evoked potentials (SEPs) to electrical stimulation of the S1, L1, and T10 dermatomes was examined in two groups of ten patients in a...

  10. Muscle potentials evoked by magnetic stimulation of the sciatic nerve in unilateral sciatic nerve dysfunction

    NARCIS (Netherlands)

    Van Soens, I.; Struys, M. M. R. F.; Van Ham, L. M. L.

    2010-01-01

    Magnetic stimulation of the sciatic nerve and subsequent recording of the muscle-evoked potential (MEP) was performed in eight dogs and three cats with unilateral sciatic nerve dysfunction. Localisation of the lesion in the sciatic nerve was based on the history, clinical neurological examination an

  11. Somatosensory Evoked Potentials and Dopaminergic Responsiveness to Apomorphine and Levodopa in Parkinsonian Patients

    OpenAIRE

    Miranda, M.; J. L. Castillo; Araya, F.

    1996-01-01

    Short-latency somatosensory evoked potentials (SSEPs) were recorded from 10 parkinsonian patients in ‘off’ and ‘on’ states induced by apomorphine and levodopa. The effects of apomorphine and long-term levodopa treatment on the frontal N30 component were assessed and compared with healthy controls. Nine of 10 patients tested with apomorphine showed a significant improvement (p

  12. [Indications for studying evoked potentials in childhood. Methods--indications--value].

    Science.gov (United States)

    Görke, W

    1986-01-01

    Evoked potentials (EP) represent a valuable addition to currently applied diagnostic methods in neuropediatrics. Profound knowledge of the neurophysiological conditions producing EP-alterations allows basic conclusions, that cannot be gained or replaced by other investigations. EP-investigation demonstrate the existence but not the nature of a lesion in the CNS. Further diagnostic work-up usually will be necessary. Proved EP-alterations produce reproducible diagnostic results and give clues regarding its localization. Evoked potentials can be used as a screening-method for neuropediatric diseases. By follow-up examinations it is possible to show, wether there is progression or not. Testing for evoked potentials is indicated in suspected cerebral palsy in infants, in all cases of psychomotor retardation of unknown origin, impairment of vision or hearing, in cases of brain trauma or in suspected brainstem process, lesions of N. opticus or visual projective systems, neurometabolic or degenerative CNS disease, phacomatosis, progressive myoclonic epilepsy, ceroidlipofuscinosis Jansky-Bielschowski, benign partial epilepsy with extreme somatosensory evoked potentials, Ramsey-Hunt-Syndrome and aplasia of the corpus callosum.

  13. EVOKED POTENTIALS OF OBSESSIVE-COMPULSIVE DISORDER:STATE OR TRAIT MARKER

    Institute of Scientific and Technical Information of China (English)

    肖泽萍; 陈兴时; 张明岛; 楼翡璎; 陈珏

    2004-01-01

    Objective To investigate the status of evoked potentials in obsessive-compulsive disorder (OCD). Methods Evoked potentials P300 , auditory brainstem response ( ABR ) and visual evoked potential (VEP) were recorded from 35 OCD patients and 28 normal controls (NC) with a Nicolet Spirit Instrument. 23 of the OCD patients were followed up after 5 months with the same markers. Results Compared with NC, OCD patients showed decreased P3 of P300 amplitude ( OCD group 3.5 + 1.6μv vs. NC group 5.9 +2.1 μv, P <0.01 ),delayed V latency (6.4 +0. 4ms vs. 5.5 +0.3ms, P <0.01 ) and increased V amplitude( 0.35 ±0.1μv vs. 0.16 ±0.09μv, P <0.05)of ABR and delayed P2 of VEP latency (199 ±39ms vs. 183 +28ms, P <0. 05). The followup measures of evoked potentials suggested that decreased P3 of P300 amplitude and delayed P2 of VEP latency might be state markers of OCD , while decreased V amplitude and delayed V of ABR latency might be trait markers of OCD. Conclusion The changes of P300 and VEP are related to clinical status of OCD patients, while the association between ABR and OCD symptoms need to be further investigated.

  14. [Intraoperative monitoring: visual evoked potentials in surgery of the sellar region].

    Science.gov (United States)

    Lorenz, M; Renella, R R

    1989-01-01

    During 18 sellar and perisellar operations the optic tract was monitored by visual evoked potentials (VEP). Deteriorations of the cortical responses were recorded in 73%. In this patients there was no close correlation between the intraoperative findings and the postoperative visual function. Only in those patients who showed no remarkable intraoperative changes VEP seemed to be of reliable prognostic value.

  15. Cortical evoked potential and extracellular K+ and H+ at critical levels of brain ischemia

    DEFF Research Database (Denmark)

    Astrup, J; Symon, L; Branston, N M;

    1977-01-01

    + as well as evoked potential were made in the baboon neocortex. Reductions in blood flow were obtained by occlusion of the middle cerebral artery and depression beyond the ischemic threshold of electrical function achieved by a reduction of systemic blood pressure which, in the ischemic zones, changed...

  16. Intraoperative monitoring study of ipsilateral motor evoked potentials in scoliosis surgery

    OpenAIRE

    Lo, Y. L.; Dan, Y. F.; Tan, Y. E.; Fook-Chong, S; Tan, S. B.; Tan, C T; Raman, S.

    2006-01-01

    Ipsilateral motor evoked potentials (MEPs) in spinal cord surgery intraoperative monitoring is not well studied. We show that ipsilateral MEPs have significantly larger amplitudes and were elicited with lower stimulation intensities than contralateral MEPs. The possible underlying mechanisms are discussed based on current knowledge of corticospinal pathways. Ipsilateral MEPs may provide additional information on the integrity of descending motor tracts during spinal surgery monitoring.

  17. Comparison of the pattern reversal visual evoked potential mediated by separate cone systems

    DEFF Research Database (Denmark)

    Johnsen, B; Frederiksen, J.L.; Larsson, H.B.

    1995-01-01

    With the purpose of recording responses mediated by the 3 cone systems visual evoked potentials (VEPs) were elicited by the reversal of monochromatic checkerboards superimposed upon strong monochromatic backgrounds (yellow, purple and blue-green). The sensitivity to light of various wave lengths...

  18. Simultaneous Recording of Electroretinography and Visual Evoked Potentials in Anesthetized Rats.

    Science.gov (United States)

    Nguyen, Christine T; Tsai, Tina I; He, Zheng; Vingrys, Algis J; Lee, Pei Y; Bui, Bang V

    2016-01-01

    The electroretinogram (ERG) and visual evoked potential (VEP) are commonly used to assess the integrity of the visual pathway. The ERG measures the electrical responses of the retina to light stimulation, while the VEP measures the corresponding functional integrity of the visual pathways from the retina to the primary visual cortex following the same light event. The ERG waveform can be broken down into components that reflect responses from different retinal neuronal and glial cell classes. The early components of the VEP waveform represent the integrity of the optic nerve and higher cortical centers. These recordings can be conducted in isolation or together, depending on the application. The methodology described in this paper allows simultaneous assessment of retinal and cortical visual evoked electrophysiology from both eyes and both hemispheres. This is a useful way to more comprehensively assess retinal function and the upstream effects that changes in retinal function can have on visual evoked cortical function. PMID:27404129

  19. Action Principle for Potential Flows

    CERN Document Server

    Frønsdal, Christian

    2014-01-01

    The restriction of hydrodynamics to non-viscous, potential (gradient, irrotational) flows is a theory both simple and elegant; a favorite topic of introductory textbooks. It is known that this theory (under the stated limitations) can be formulated as an action principle. It finds its principle application to adiabatic systems and cannot account for viscosity or dissipation. However, it can be generalized to include non-potential flows, as this paper shows. The new theory is a combination of Eulerian and Lagrangian hydrodynamics, with an extension to thermodynamics. It describes adiabatic phenomena but does not account for viscosity or dissipation. Nevertheless, it is an approach within which quasi-static processes can be described. In the adiabatic context it appears to be an improvement of the Navier-Stokes equation, the principal advantage being a natural concept of energy in the form of a first integral of the motion, conserved by virtue of the Euler-Lagrange equations.

  20. Do resting brain dynamics predict oddball evoked-potential?

    Directory of Open Access Journals (Sweden)

    Lee Tien-Wen

    2011-11-01

    Full Text Available Abstract 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.

  1. Modified variance ratio for objective detection of transient evoked potentials in bottlenose dolphins (Tursiops truncatus).

    Science.gov (United States)

    Finneran, James J

    2008-12-01

    Evoked potential studies have often relied on one or more human observers to visually assess the averaged waveforms and decide if a response is present. Although simple and easy to implement, response detection strategies based on human observers are inherently subjective and depend on the observers' experience and biases. To avoid these shortcomings, some recent marine animal studies utilizing auditory steady-state responses have applied frequency-domain, statistically based objective detection methods; however, statistically based objective methods have not yet been applied to marine animal tests involving transient evoked responses, which are normally analyzed in the time domain. The present study applied a modified version of the variance ratio F(SP) to determine the presence or absence of evoked responses in two bottlenose dolphins (Tursiops truncatus) stimulated with tone pips. The appropriate degrees of freedom for the statistical tests were empirically determined in four dolphins. The modified variance ratio was found to be a useful tool and to provide an objective statistical approach for the detection of transient evoked potentials. PMID:19206829

  2. Visual and noxious electrical stimulus-evoked membrane-potential responses in anterior cingulate cortical neurons.

    Science.gov (United States)

    Ma, Li-Qing; Ning, Li; Wang, Zhiru; Wang, Ying-Wei

    2016-01-01

    Anterior cingulate cortex (ACC) is known to participate in numerous brain functions, such as memory storage, emotion, attention, as well as perception of acute and chronic pain. ACC-dependent brain functions often rely on ACC processing of various forms of environmental information. To understand the neural basis of ACC functions, previous studies have investigated ACC responses to environmental stimulation, particularly complex sensory stimuli as well as award and aversive stimuli, but this issue remains to be further clarified. Here, by performing whole-cell recording in vivo in anaesthetized adult rats, we examined membrane-potential (MP) responses of layer II/III ACC neurons that were evoked by a brief flash of visual stimulation and pain-related electrical stimulation delivered to hind paws. We found that ~54 and ~81 % ACC neurons exhibited excitatory MP responses, subthreshold or suprathreshold, to the visual stimulus and the electrical stimulus, respectively, with no cell showing inhibitory MP responses. We further found that the visually evoked ACC response could be greatly diminished by local lidocaine infusion in the visual thalamus, and only their temporal patterns but not amplitudes could be changed by large-scale visual cortical lesions. Our in vivo whole-cell recording data characterized in ACC neurons a visually evoked response, which was largely dependent on the visual thalamus but not visual cortex, as well as a noxious electrical stimulus-evoked response. These findings may provide potential mechanisms that are used for ACC functions on the basis of sensory information processing. PMID:27585569

  3. Long-latency auditory evoked potentials with verbal and nonverbal stimuli,

    OpenAIRE

    Sheila Jacques Oppitz; Dayane Domeneghini Didoné; Débora Durigon da Silva; Marjana Gois; Jordana Folgearini; Geise Corrêa Ferreira; Michele Vargas Garcia

    2015-01-01

    ABSTRACT INTRODUCTION: Long-latency auditory evoked potentials represent the cortical activity related to attention, memory, and auditory discrimination skills. Acoustic signal processing occurs differently between verbal and nonverbal stimuli, influencing the latency and amplitude patterns. OBJECTIVE: To describe the latencies of the cortical potentials P1, N1, P2, N2, and P3, as well as P3 amplitude, with different speech stimuli and tone bursts, and to classify them in the presence and...

  4. Effects of carnosine on the evoked potentials in hippocampal CA1 region*

    OpenAIRE

    Feng, Zhou-yan; Zheng, Xiao-jing; Wang, Jing

    2009-01-01

    Objective: To directly examine the effects of carnosine on neuronal excitation and inhibition in rat hippocampus in vivo. Methods: Artificial cerebrospinal fluid with carnosine was directly administrated over the exposed rat hippocampus. The changes of neuron activity in the CA1 region of hippocampus were evaluated by orthodromically- and antidromically-evoked potentials, as well as paired-pulse stimulation paradigm. Results: In both orthodromic and antidromic response potentials, carnosine t...

  5. Vestibular Dysfunctions in Cochlear Implant Patients; A Vestibular Evoked Myogenic Potential Study

    Directory of Open Access Journals (Sweden)

    Masoud Motasaddi Zarandy

    2011-12-01

    Full Text Available Background and Aim: Vestibular evoked myogenic potential in response to click or short tone burst stimuli have been used as a clinical test for distinguish saccule and inferior vestibular nerve diseases. Different studies show that cochlear implant could have inverse effects on vestibular structures. We aimed to investigate vestibular evoked myogenic potential in unilateral cochlear implanted individuals in compare to normal individuals.Methods: Thirty-three unilateral cochlear implanted patients (mean age 19.96 years and 30 normal hearing individuals (mean age 24-27 years as control group were enrolled in this cross- sectional study. Absolute latencies and amplitudes of myogenic potential responses were measured and compared in both groups.Results: Myogenic potential recorded in both ears of all controls were normal. No response could be recorded in 16 patients (48.48% from both ears. In three patients, responses were recorded in both ears though the amplitude of waves was reduced in implanted ear. Unilateral response could be recorded in 14 patients only in their non-implanted ear.Conclusion: Vestibular evoked myogenic potential test is a useful tool for assessing saccular function in cochlear implant patients. Damages of osseous spiral lamina and basilar membrane after cochlear implantation could result in dysfunctions of vestibular organs specially saccule. It seems that saccule could be easily damaged after cochlear implantation. This would cause absence or reduced amplitudes in myogenic potential.

  6. The Single Training Sample Extraction of Visual Evoked Potentials Based on Wavelet Transform

    Institute of Scientific and Technical Information of China (English)

    LIU Fang; ZHANG Zhen; CHEN Wen-chao; QIN Bing

    2007-01-01

    Abstract.Based on the good localization characteristic of the wavelet transform both in time and frequency domain, a de-noising method based on wavelet transform is presented, which can make the extraction of visual evoked potentials in single training sample from the EEG background noise in favor of studying the changes between the single sample response happen. The information is probably related with the different function, appearance and pathologies of the brain. At the same time this method can also be used to remove those signal' s artifacts that do not appear with EP within the same scope of time or frequency. The traditional Fourier filter can hardly attain the similar result. This method is different from other wavelet de-noising methods in which different criteria are employed in choosing wavelet coefficient. It has a biggest virtue of noting the differences among the single training sample and making use of the characteristics of high time frequency resolution to reduce the effect of interference factors to a maximum extent within the time scope that EP appear. The experiment result proves that this method is not restricted by the signal-tonoise ratio of evoked potential and electroencephalograph (EEG) and even can recognize instantaneous event under the condition of lower signal-to-noise ratio, as well as recognize the samples which evoked evident response more easily. Therefore, more evident average evoked response could be achieved by de-nosing the signals obtained through averaging out the samples that can evoke evident responses than de-nosing the average of original signals. In addition, averaging methodology can dramatically reduce the number of record samples needed, thus avoiding the effect of behavior change during the recording process.This methodology pays attention to the differences among single training sample and also accomplishes the extraction of visual evoked potentials from single trainings sample. As a result, system speed and

  7. Value of somatosensory evoked potentials in diagnosis, surgical monitoring and prognosis of cervical spondylotic myelopathy

    Institute of Scientific and Technical Information of China (English)

    DING Yu; HU Yong; RUAN Di-ke; CHEN Bo

    2008-01-01

    Background The value of somatosensory evoked potentials (SEPs) in the diagnosis and prognosis of cervical spondylotic myelopathy, as well as the usefulness of monitoring intraoperative potentials in terms of safety and predictive factors were investigated.Methods Each of the 76 myelopathic patients underwent surgical intervention. According to the wave configurations of the SEPs, the cases were categorised into four groups: Type Ⅰ, Ⅱ, Ⅲ and Ⅳ. The clinical myelopathy disability was classified and the severity of neurological deficits was scored. Clinical function after surgery was evaluated. Preoperative potentials and intraoperative monitoring were categorized. The correlations between evoked potentials detection, monitoring, myelopathy disability and surgical outcome in the different groups were discussed. Results According to the configurations of the SEPs, there were 27 patients (36%) of Type Ⅰ, 30 patients (39%) of Type Ⅱ, 8 patients (11%) of Type Ⅲ, and 11 patients (14%) of Type Ⅳ. The categorised evoked potentials were shown to be significantly associated with the clinical representation of myelopathy (P 〈0.01) and the recovery rate from identifiable SEPs waves (groups A, B and C) was significantly higher than unidentifiable waves (group D, P〈0.01). A deterioration of SEPs was detected in 23 cases (30%), whereas there was no change in 40 cases (53%) and improvements in 13 cases (17%). A significant difference in recovery rates could be observed in various monitoring groups within the short-term follow-up period, while there were no obvious differences in the long-term follow-up groups. Conclusions SEP technique is a valuable and practical tool for the diagnosis, monitoring and prognosis of myelopathy. Classified evoked potentials are well correlated with cervical spondyiotic myelopathy disability, and unidentifiable SEPs waves in patients are indicative of a relatively poor outcome. In addition, intraoperative monitoring of SEPs plays an

  8. Spontaneous EEG spikes in the normal hippocampus. III. Relations to evoked potentials.

    Science.gov (United States)

    Suzuki, S S; Smith, G K

    1988-06-01

    Spontaneous EEG spikes (SPKs) were recorded from the CA1 region of the dorsal hippocampus in normal rats during behavioral states not accompanied by rhythmical slow activity (RSA). SPKs were positive in stratum oriens, negative in stratum radiatum and accompanied by population bursts (PBs) in stratum pyramidale. In order to examine the origin of SPKs and PBs single pulse or brief high frequency electrical stimuli were applied to the Schaffer collateral/commissural pathway. Evoked potentials were recorded and compared with spontaneous SPKs and PBs. The results indicate the following: (1) the laminar amplitude profile of spontaneous SPKs was similar to that of population EPSPs evoked by stimulation of the Schaffer collateral/commissural pathway; (2) the population EPSP most similar to the spontaneous SPK was evoked by a brief (20-60 msec) train of high frequency (125-500 Hz) pulses; (3) the same pattern of stimulation was also found to be most efficient in evoking a series of multiple population spikes resembling a type of spontaneous PB (ripple). These observations suggest that SPKs and PBs in CA1 represent population EPSPs and multiple population spikes, respectively and that these CA1 events are triggered by brief, high frequency burst discharges of CA3 pyramidal cells via the Schaffer collateral and commissural pathway. PMID:2453331

  9. Light-triggered action potentials in plants

    OpenAIRE

    Kazimierz Trębacz

    2014-01-01

    Special attention is paid in this paper to the criteria of the light-triggered action potential, namely the all-or-none law, propagation, the occurrence of refractory periods. Such action potentials have been recorded in Acetabularia mediterranea, Asplenium trichomanes, Bryum pseudotriquetrum, Eremosphaera viridis and Concephalum conicum. In Acetabularia, action potentials are generated after sudden cessation of light stimuli of sufficient intensity. The depolarization phase of the action pot...

  10. The Analysis of Disparity Evoked Potentials by a New Form of Static Random—Dot Stereograms

    Institute of Scientific and Technical Information of China (English)

    ChuanHou; XuexinZhang

    1995-01-01

    Purpose:A new form of static random-dot stereograms free of monoular clues was designed as stimulus to elicit disparity evoked potentials.Methods:Disparity evoked potentials were recorded in 40stereo-normal subjects.The stimulator was a white-black static random-dot stereograms generated by a computer and had no monocular clues.Every subject was tested in disparity stim-ulus,zero disparity stimulus,monocuular stimulus and wearing prism condition.Results:A characteristic wide positive wave at about 250ms was consistantly recorded in disparity stimulus,which amy be regarded as evidence of the the pres-ence of stereopsis .In contrast,recordings for zero disparity stimulus,monocular vision,stimulus and wearing prism condition all demonstrated a markedly differ-ence from recording for disparity stimulus.

  11. Visual evoked potentials in dementia: a meta-analysis and empirical study of Alzheimer's disease patients.

    Science.gov (United States)

    Pollock, V E; Schneider, L S; Chui, H C; Henderson, V; Zemansky, M; Sloane, R B

    1989-04-15

    A meta-analytic review of flash and pattern reversal visual evoked potential research indicates that elderly demented patients have longer P100 latencies than age-matched control subjects. In the present empirical research, patients with research diagnoses of probable Alzheimer's disease were compared with sex- and age-matched control subjects using P100 latencies of visual evoked potentials (VEP) elicited by flash and pattern reversal. As compared to control subjects, Alzheimer's disease patients showed significantly longer P100 latencies of the VEP elicited by pattern reversal; the flash P100 only marginally distinguished them. These findings are discussed within the context of VEP recording practices, patient selection, sex and age matching of control subjects, and the visual system.

  12. Effect of cerebral lymphatic block on cerebral morphology and cortical evoked potential in rats

    Institute of Scientific and Technical Information of China (English)

    Zuoli Xia; Baoling Sun; Mingfeng Yang; Dongmei Hu; Tong Zhao; Jingzhong Niu

    2006-01-01

    BACKGROUND: It has been shown that although brain does not contain lining endothelial lymphatic vessel,it has lymphatic drain.Anterior lymphatic vessel in brain tissue plays a key role in introducing brain interstitial fluid to lymphatic system;however,the significance of lymphatic drain and the affect on cerebral edema remains unclear.OBJECTIVE: To investigate the effect of cerebral lymphatic block on cerebral morphology and cortical evoked potential in rats.DESIGN: Randomized controlled animal study.SETTING: Institute of Cerebral Microcirulation of Taishan Medical College and Department of Neurology of Affiliated Hospital.MATERIALS:A total of 63 healthy adult male Wistar rats weighing 300-350 g were selected in this study.Forty-seven rats were used for the morphological observation induced by lymphatic drain and randomly divided into three groups:general observation group(n=12),light microscopic observation group(n=21)and electronic microscopic observation group(n=14).The rats in each group were divided into cerebral lymphatic block subgroup and sham-operation control subgroup.Sixteen rats were divided into cerebral the effect of cerebral lymphatic block on cortical evoked potential,in which the animals were randomly divided into sham-operation group(n=6)and cerebral lymphatic block group(n=10).METHODS:The experiment was carried out in the Institute of Cerebral Microcirculation of Taishan Medical College from January to August 2003.Rats in cerebral lymphatic block group were anesthetized and separated bilateral superficial and deep cervical lymph nodes under sterile condition. Superior and inferior boarders of lymph nodes were ligated the inputting and outputting channels, respectively, and then lymph node was removed so as to establish cerebral lymphatic drain disorder models. Rats in sham-operation control group were not ligated the lymphatic vessel and removed lymph nodes.and other operations were as the same as those in cerebral lymphatic block group

  13. The effects of halothane on somatosensory and flash visual evoked potentials during operations.

    Science.gov (United States)

    Wang, A D; Costa e Silva, I; Symon, L; Jewkes, D

    1985-06-01

    Intraoperative use of somatosensory evoked potentials (SEP's) to monitor intracranial aneurysm surgery and flash visual evoked potentials (F-VEP's) for parasellar surgery have been routinely employed in our clinic. We found that both EP modalities are sensitive to the changing concentration of our standard hypotensive agent, halothane. The prolongation of the N14-N20 interpeak latency to median nerve stimulation at the wrist, and prolongation of P100 latency with altered configuration of early VEP components to flash light stimulation, appear to be the results of direct pharmacological effects of the agent and not an effect of secondary hypotension. VEP is found easily abolished by halothane at a concentration of 2.0%, while the SEP is more resistant. Halothane is not ideal however when monitoring intraoperative VEP.

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

    Science.gov (United States)

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

    2014-09-01

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

  15. Effect of extradural morphine on somatosensory evoked potentials to dermatomal stimulation

    DEFF Research Database (Denmark)

    Lund, C; Selmar, P; Hansen, O B;

    1987-01-01

    The effect of the extradural (L2-3) administration of morphine 6 mg on early (less than 0.5 s) somatosensory evoked cortical potentials (SEP) to electrical stimulation of the L1- and S1-dermatomes was examined in eight patients. Extradural morphine did not influence SEP amplitude. SEP latency did...... not change, except for a minor increase in the latencies of the onset and the P2 components following S1 stimulation....

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

    OpenAIRE

    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

  17. Comparison of Auditory Evoked Potentials in Heterosexual, Homosexual, and Bisexual Males and Females

    OpenAIRE

    McFadden, Dennis; Champlin, Craig A.

    2000-01-01

    The auditory evoked potentials (AEPs) elicited by click stimuli were measured in heterosexual, homosexual, and bisexual males and females having normal hearing sensitivity. Estimates of latency and/or amplitude were extracted for nine peaks having latencies of about 2–240 ms, which are presumed to correspond to populations of neurons located from the auditory nerve through auditory cortex. For five of the 19 measures obtained, the mean latency or amplitude for the 57 homosexual and bisexual f...

  18. Somatosensory Evoked Potentials and Dopaminergic Responsiveness to Apomorphine and Levodopa in Parkinsonian Patients

    Directory of Open Access Journals (Sweden)

    M. Miranda

    1996-01-01

    Full Text Available Short-latency somatosensory evoked potentials (SSEPs were recorded from 10 parkinsonian patients in ‘off’ and ‘on’ states induced by apomorphine and levodopa. The effects of apomorphine and long-term levodopa treatment on the frontal N30 component were assessed and compared with healthy controls. Nine of 10 patients tested with apomorphine showed a significant improvement (p

  19. Somatosensory evoked potentials following stimulation of the lower limb in cortical reflex myoclonus.

    OpenAIRE

    Kakigi, R; Shibasaki, H

    1987-01-01

    Generating mechanisms of giant somatosensory evoked potentials (SEPs) following stimulation of the posterior tibial nerve as well as the big toe were investigated in three patients with cortical reflex myoclonus. Scalp distributions of recognisable components were very similar to those in normal subjects, except that their amplitude was much larger. The tibial nerve SEPs were remarkably attenuated by interfering tactile stimulation. Therefore, the giant SEPs observed in the present cases seem...

  20. Steady state visually evoked potentials based Brain computer interface test outside the lab

    OpenAIRE

    Eduardo Francisco Caicedo Bravo; Jaiber Evelio Cardona Aristizábal

    2016-01-01

    Context: Steady State Visually Evoked Potentials (SSVEP) are brain signals which are one of the most promising signals for Brain Computer Interfaces (BCIs) implementation, however, SSVEP based BCI generally are proven in a controlled environment and there are a few tests in demanding conditions.Method: We present a SSVEP based BCI system that was used outside the lab in a noisy environment with distractions, and with the presence of public. For the tests, we showed a maze in a laptop where th...

  1. The VESPA: A method for the rapid estimation of a visual evoked potential

    OpenAIRE

    Lalor, Edmund C.; Pearlmutter, Barak A.; Richard B. Reilly; McDarby, Gary; Foxe, John J.

    2006-01-01

    Faster and less obtrusive means for measuring a Visual Evoked Potential would be valuable in clinical testing and basic neuroscience research. This study presents a method for accomplishing this by smoothly modulating the luminance of a visual stimulus using a stochastic process. Despite its visually unobtrusive nature, the rich statistical structure of the stimulus enables rapid estimation of the visual system's impulse response. The profile of these responses, which we ...

  2. Attachment style moderates partner presence effects on pain:a laser-evoked potentials study

    OpenAIRE

    Krahé, Charlotte; Paloyelis, Yannis; Condon, Heather; Jenkinson, Paul M.; Williams, Steven C R; Fotopoulou, Aikaterini (Katerina)

    2015-01-01

    Social support is crucial for psychological and physical well-being. Yet, in experimental and clinical pain research, the presence of others has been found to both attenuate and intensify pain. To investigate the factors underlying these mixed effects, we administered noxious laser stimuli to 39 healthy women while their romantic partner was present or absent, and measured pain ratings and laser-evoked potentials (LEPs) to assess the effects of partner presence on subjective pain experience a...

  3. Trigeminal evoked potentials in patients with symptomatic trigeminal neuralgia due to intracranial mass lesions.

    OpenAIRE

    Sundaram P; Hegde A; Chandramouli B; Das B

    1999-01-01

    Trigeminal evoked potentials (TEP) were recorded by electrical stimulation of the lips in 7 patients with symptomatic trigeminal neuralgia due to CT proved mass lesions involving the trigeminal nerve. All the patients showed TEP abnormalities on the affected side. Chronic compression and irritation of the trigeminal nerve may be responsible for these changes. The results obtained were compared with other similar studies and TEP abnormalities observed in idiopathic trigeminal neuralgia. As all...

  4. Enhancement of the amplitude of somatosensory evoked potentials following magnetic pulse stimulation of the human brain.

    Science.gov (United States)

    Seyal, M; Browne, J K; Masuoka, L K; Gabor, A J

    1993-01-01

    In this study we have demonstrated an enhancement of cortically generated wave forms of the somatosensory evoked potential (SEP) following magnetic pulse stimulation of the human brain. Subcortically generated activity was unaltered. The enhancement of SEP amplitude was greatest when the median nerve was stimulated 30-70 msec following magnetic pulse stimulation over the contralateral parietal scalp. We posit that the enhancement of the SEP is the result of synchronization of pyramidal cells in the sensorimotor cortex resulting from the magnetic pulse.

  5. The value of bilateral ipsilateral and contralateral motor evoked potential monitoring in scoliosis surgery

    OpenAIRE

    Lo, Y. L.; Dan, Y. F.; Teo, A; Tan, Y. E.; Yue, W. M.; Raman, S.; Tan, S. B.

    2007-01-01

    Intraoperative monitoring (IOM) of the motor pathways is a routine procedure for ensuring integrity of corticospinal tracts during scoliosis surgery. We have previously demonstrated presence of ipsilateral motor evoked potentials (MEPs) during IOM for scoliosis surgery, but its significance was uncertain. In this case series, we show concurrent ipsilateral and contralateral MEP amplitude changes obtained with cortical stimulation are of value in reducing false positive observations during IOM...

  6. Auditory evoked potentials in the West Indian Manatee (Sirenia: Trichechus manatus)

    Science.gov (United States)

    Bullock, Theodore H.; O'Shea, Thomas J.; McClune, Michael C.

    1982-01-01

    Potentials evoked by clicks and tone pips were recorded by fine wires inserted extracranially in four West Indian manatees (Trichechus manatus) in air. Sounds were delivered via padded ear phones. Averaging a few thousand trials at 20/s reveals early peaks at N5.4 (‘vertex’ negativity to a frontal reference, at 5.4 ms), P7.6, N8.8, P9.5 — probably equivalent to waves IV and VII of the typical mammalian auditory brainstem response (ABR). Averaging 100 trials at Using tone pips with a rise and fall time of 2–5 ms the carrier frequency becomes important. Evoked potential wave forms are not the same at different frequencies, bringing out the fact that frequency is not a scalar that can be compensated for by intensity. Therefore the method was not used to obtain audiograms; however the largest EPs occur in the range of 1–1.5 kHz. EPs are found up to 35 kHz; almost no evoked potential is discernible at 40 kHz but the undistorted intensity available was limited. This is in reasonable agreement with the theoretical expectation for the upper limit of behavioral hearing from Heffner and Masterton based on head size and aquatic medium.

  7. A portable device for recording evoked potentials, optimized for pattern ERG.

    Science.gov (United States)

    McInturff, Stephen P; Buchser, William J

    2016-02-01

    Recording evoked potentials in un-anesthetized animals and people is a powerful technique to non-invasively measure the function of neurons. As such, the primary output neurons of the eye can be assessed by the pattern electroretinogram (PERG). Currently, electro-physiologic setups to perform PERG or related recordings are costly, complicated, and non-portable. Here, we design a simple steady-state PERG system, based off an Arduino board. The amplifier is built on a shield that fits over a microcontroller board, an Arduino, which digitizes the signal and sends it to a computer that presents stimuli then records and analyzes the evoked potentials. We used the device to record PERG accurately with a sensitivity as low as half a microvolt. The device has also been designed to implement other evoked potential recordings. This simple device can be quickly constructed and used for experiments in moving systems. Additionally, this device can be used to expose students in underserved areas to research technology that they would otherwise not have access to. PMID:26536572

  8. Nociceptive-Evoked Potentials Are Sensitive to Behaviorally Relevant Stimulus Displacements in Egocentric Coordinates.

    Science.gov (United States)

    Moayedi, M; Di Stefano, G; Stubbs, M T; Djeugam, B; Liang, M; Iannetti, G D

    2016-01-01

    Feature selection has been extensively studied in the context of goal-directed behavior, where it is heavily driven by top-down factors. A more primitive version of this function is the detection of bottom-up changes in stimulus features in the environment. Indeed, the nervous system is tuned to detect fast-rising, intense stimuli that are likely to reflect threats, such as nociceptive somatosensory stimuli. These stimuli elicit large brain potentials maximal at the scalp vertex. When elicited by nociceptive laser stimuli, these responses are labeled laser-evoked potentials (LEPs). Although it has been shown that changes in stimulus modality and increases in stimulus intensity evoke large LEPs, it has yet to be determined whether stimulus displacements affect the amplitude of the main LEP waves (N1, N2, and P2). Here, in three experiments, we identified a set of rules that the human nervous system obeys to identify changes in the spatial location of a nociceptive stimulus. We showed that the N2 wave is sensitive to: (1) large displacements between consecutive stimuli in egocentric, but not somatotopic coordinates; and (2) displacements that entail a behaviorally relevant change in the stimulus location. These findings indicate that nociceptive-evoked vertex potentials are sensitive to behaviorally relevant changes in the location of a nociceptive stimulus with respect to the body, and that the hand is a particularly behaviorally important site. PMID:27419217

  9. Effect of Prophylactic Drugs on Vestibular Evoked Myogenic Potential in Migraine Patients

    Directory of Open Access Journals (Sweden)

    Shohre Jalaie

    2012-10-01

    Full Text Available Background and Aim: In many migraine patients prophylactic drugs are effective in reducing attacks and symptoms such as vestibular complaints. Therefore, related neural pathways are probably alsoaffected. This study aimed to compare vestibular evoked myogenic potential in migraine patients under treatment with prophylactic drugs and those without any treatment.Methods: Subjects included 46 patients with migraine. They were evaluated in two groups; those under treatment with prophylactic drugs (21 subjects and those without treatment (25 subjects. Theage range of patients was 20-60 years. The vestibular evoked myogenic potential were recorded with 500 Hz tone bursts at 95 dB nHL.Results: Mean of amplitude ratio (p=0.02, and interpeak latency values in the right ear (p=0.03 and left ear (p=0.001 were higher in patients with prophylactic therapy than the group without therapy;this difference was statistically significant. There was no statistical difference between the two groups in terms of mean of latency of p13 and n23 peaks, and absolute amplitude (p>0.05.Conclusion: Prophylactic drugs probably improve mean of main response parameters of vestibular evoked myogenic potential in migraine patients with prophylactic therapy.

  10. Changes of evoked potentials and evaluation of mild hypothermia for treatment of severe brain injury

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Objective: To observe the changes of evoked pote ntials after severe brain injury and the effect of mild hypothermia on acute sev ere brain injury.   Methods: A total of 44 patients with severe closed head injury (GCS 3-8, admitted within 10 hours from injury) admitted from May 1998 to March 1999 were selected for this study. All patients were admitted into the intensiv e care unit and divided into 2 groups, Group A (GCS 3-5) and Group B (GCS 6 -8). Patients were also randomly assigned to either normothermia or hypothermia subgroups. Patients in the hypothermia group were cooled to 32-34℃. Median nerve short-latency somatosensory evoked potentials (SLSEP) and brain stem aud itory evoked potentials (BAEP) were recorded before cooling and 4, 24, 48, 72, 9 6 and 120 hours, respectively after cooling and temperature resuming. SLSEP and BAEP were measured at the same time in the normothermia group (control group). T he changes of evoked potentials (EP) were analyzed by statistical methods.   Results: In the Group B, N20 amplitudes in SLSEP and I/V amplitudes in BAEP after mild hypothermia treatment in the hypothermia group dif fered significantly from those in the control group (P<0.05). However, in the Group A, no significant difference in all paramet ers was found.   Conclusions: These results demonstrate that mild hypothermia tr eatment (32-34℃) in the Group B has a significant neuroelectrophysiological effect on severe brain injury. Nevertheless, the effect of mild hypothermia in t he Group A is not apparent and needs further studying.

  11. The effect of changes in perilymphatic K+ on the vestibular evoked potential in the guinea pig.

    Science.gov (United States)

    Kingma, C M; Wit, H P

    2010-11-01

    To investigate the effect on the functioning of the vestibular system of a rupture of Reissner's membrane, artificial endolymph was injected in scala media of ten guinea pigs and vestibular evoked potentials (VsEPs), evoked by vertical acceleration pulses, were measured. Directly after injection of a sufficient volume to cause rupture, all ears showed a complete disappearance of VsEP, followed by partial recovery. To investigate the effect of perilymphatic potassium concentration on the vestibular sensory and neural structures, different concentrations of KCl were injected directly into the vestibule. The KCl injections resulted in a dose-dependent decrease of VsEP, followed by a dose-dependent slow recovery. This animal model clearly shows a disturbing effect of a higher than normal K(+) concentration in perilymph on the vestibular and neural structures in the inner ear. Potassium intoxication is the most probable explanation for the observed effects. It is one of the explanations for Menière attacks.

  12. V ISUAL EVOKED POTENTIALS IN TYPE - 1 DIABETES WITHOUT RETINOPATHY: CO - RELATIONS WITH DURATION OF DIABETES

    Directory of Open Access Journals (Sweden)

    Sanjeev Kumar

    2014-01-01

    Full Text Available 20 diabetic (Type 1 patients have been studied in order to investigate the possible effects of the type 1 diabetes mellitus on the central nervous system by means of pattern shift visual evoked potentials. Patients with diabetic retinopathy , glaucoma and cataract were excluded from the study. To evaluate central optic pathways involvement in diabetics , visual evoked po tentials (VEP , in particular the latency of positive peak (P100 , were studied in 20 patients and 20 normal controls using reversal pattern VEP. P100 latency was significantly increased in diabetics. A positive co - relation was also found between latencies of VEP and duration of disease. Relationship between blood sugar level and P 100 wave latencies and amplitudes in diabetic patients was not significant . VEP measurement seems a simple and sensitive method for detecting early involvement and changes in opti c pathways in diabetics

  13. Abstract Action Potential Models for Toxin Recognition

    OpenAIRE

    Peterson, James; Khan, Taufiquar

    2005-01-01

    In this paper, we present a robust methodology using mathematical pattern recognition schemes to detect and classify events in action potentials for recognizing toxins in biological cells. We focus on event detection in action potential via abstraction of information content into a low dimensional feature vector within the constrained computational environment of a biosensor. We use generated families of action potentials from a classic Hodgkin–Huxley model to verify our methodology and build...

  14. 人工耳蜗植入前电刺激听神经复合动作电位检测方法的建立和初步应用%The Establishment and Application of Electrically Evoked Auditory Nerve Compound Action Potential Test Method before Cochlear Implantation

    Institute of Scientific and Technical Information of China (English)

    王斌; 曹克利; 魏朝刚; 王轶; 路远

    2012-01-01

    目的 建立术中利用探测电极施行电刺激听神经复合动作电位(electrically evoked auditory nerve compound active potentials,ECAP)检测的方法,在植入人工耳蜗装置前评估患者耳蜗听神经功能状况.方法 选择20例人工耳蜗植入患者,其中耳蜗形态发育正常12例,5例双侧前庭导水管扩大,3例双侧耳蜗Mondini畸形.测试完成后全部使用Cochlear人工耳蜗.全麻后常规人工耳蜗手术进路,行标准耳蜗鼓阶开窗,将自制测试用多通道试验电极置入鼓阶,电极连接Cochlear公司体外言语处理器及自制电刺激发生器,连接电脑,采用Custom Sound EP 2.0软件,调整优化刺激参数进行神经反应遥测(neural responsetelemetry,NRT)初步了解听神经功能状态;刺激强度以5 CL为步长递减或递增至反应阈值给予电刺激脉冲,同时自动记录ECAP波形和阈值.植入人工耳蜗后常规进行NRT检测,记录ECAP波形和阈值;术后1个月患者开机后采集T、C值,将两种电极测试所得阈值和开机C值进行相关性研究,并进行数据统计分析.结果 试验电极ECAP引出率为90%,商业电极ECAP引出率为90%,平均阈值分别为(160.50±15.12)CL和(160.00±11.27)CL,两者经统计学检验没有显著性差异(P>0.05);和开机后C值(177.40±10.61)有明显相关性(R2=0.844,r=0.919).结论 成功建立了术中植入人工耳蜗装置前的ECAP检测方法,为内耳和/或听觉通路发育异常及无残余听力患者提供有效的听神经反应信息,对了解听觉系统发育程度及初步预测术后患者康复情况提供客观依据.%Objective To establish an electrically evoked auditory nerve compound action potential (ECAP) test procedure in order to assess the auditory nerve functions before cochlear implantation. Methods Twenty cochlear implant patients were selected, including 12 subjects with normal cochlear structure, 5 subjects with bilateral enlarged vestibular aqueducts, 3 with bilateral Mondini

  15. Multiple modes of action potential initiation and propagation in mitral cell primary dendrite

    DEFF Research Database (Denmark)

    Chen, Wei R; Shen, Gongyu Y; Shepherd, Gordon M;

    2002-01-01

    to support the back-propagation of the evoked somatic action potential to produce the second dendritic spike. In summary, the balance of spatially distributed excitatory and inhibitory inputs can dynamically switch the mitral cell firing among four different modes: axo-somatic initiation with back...

  16. Combined application of three evoked potentials to improve the diagnosis of multiple sclerosis

    Institute of Scientific and Technical Information of China (English)

    Xiaoyi Li

    2006-01-01

    BACKGROUND:It is very important to find out the focal sites for the ealy diagnosis of multiple sclerosis,especially the discovery of tiny or potential focal site,so that multiple sclerosis can be diagnosed at the early poriod (the first attack)or when the focus has not displayed completely.and the evoked potential can discover the abnormality of the pathway between spinal cord to cerebral cortex.OBJECTIVE:To observe the values of motor evoked potential(MEP),somatosensory evoked potential(SEP) and evoked-related potential(P300)in the diagnosis of multiple sclerosis.DESIGN:A case-controlled study.SETFING:Neuroelectrophysiological Center of Guizhou Provincial People's Hospital. PARTICIPANTS:Twenty-five outpatients or inpatients with multiple sclerosis were selected from the Department of Neurology,Guizhou Provincial People's Hospital from October 2001 to March 2005.The patients were diagnosed according to the diagnostic standards of multiple sclerosis suggested by Poser et al. In 1983 and MRI examination.There were 17 males and 8 females,aged 18-65 years old With an average of 39 years.and their disease courses ranged from 6 months to 5 years.Meanwhile.30 healthy physical examinees were selected in our hospital as the control group,and they all had no abnormality by detailed inquisition.physical examination and examination of nervous system,including 15 males and 5 females,aged 20-66 years old.All the enrolled subjects were informed and agreed with the detections.METHODS:①The MEP,SEP and P300 were detected with synergy evoked potential equipment(Oxford Instruments,UK)in all the 25 patients with multiple sclerosis and 20 healthy subjects.②Standards for judging the abnormalities of evoked potentials:The abnormalities referred to deletion of wave form or the latency was prolonged by more than the reference value of normal subject±3SD.③The differences of measurement data were compared with the t test.MAIN OUTCOME MEASURES:The results of MEP,SEP and P300 in the 25

  17. Micro-Field Evoked Potentials Recorded from the Porcine Sub-Dural Cortical Surface Utilizing a Microelectrode Array

    OpenAIRE

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

    2007-01-01

    A sub-dural surface microelectrode array designed to detect microfield evoked potentials has been developed. The device is comprised of an array of 350-micron square gold contacts, with bi-directional spacing of 150 microns, 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 ...

  18. Appropriate stimulation in visual evoked potential to evaluate visual perception state of athletes

    Institute of Scientific and Technical Information of China (English)

    Yunxiang Li; Yuzhen Zhu

    2008-01-01

    BACKGROUND: Several studies have demonstrated that visual evoked potentials can be influenced by sport events. To the best of our knowledge, there are no specific parameters for the most appropriate stimulation for evaluating the functional state of athletes. OBJECTIVE: To investigate the best stimulation in visual evoked potential to apply to functional evaluation of athletes. DESIGN, TIME AND SETTING: Ninety-five, healthy students from the Shandong Normal University took part in an observational, contrast study. PARTICIPANTS: All active participants were male. Sixty-five students majored in physical education, and had participated in exercise for the duration of (4.26±3.08) years. An additional 30 students majored in other subjects. METHODS: The neural electricity tester, NDI-200, was adapted to examine and record visual evoked potential with varying probes using bipolar electrodes attached to the head of all the participants in a dark room. The visual evoked potential values were analyzed transversally. A chessboard pattern reversal method was applied with the following parameters: 2 Hz stimulation frequency, brightness of 90 cdp, 80% contrast, 1-100 Hz bandpass filters, and 10 μ V sensitivity; 100 responses were averaged. MAIN OUTCOME MEASURES: latency, peak latencies, and inter-peak latencies were measured in N75, P100, N145 with varying probe stimulations. RESULTS: (1) Comparisons between the little check, middle check, and big check stimulation, demonstrated that the common tendencies in visual evoked potential indexes of the two groups of N75 latency were successively shorter and N145 were longer. P100-N145 peak latency was decreased and each inter-peak latency was longer. (2) Changes of N75, P10o, and NI45 with different check stimulations in the physical education student group: after compared with the middle check stimulation, N75 latency was significantly longer (P<0.01), and N75-P100 inter-peak latency (P<0.05) and N75-N145 inter-peak latency were

  19. Characteristics of brainstem auditory evoked potentials of students studying folk dance

    Institute of Scientific and Technical Information of China (English)

    Yunxiang Li; Yuzhen Zhu

    2008-01-01

    BACKGROUND:Previous experiments have demonstrated that brainstem auditory evoked potential is affected by exercise,exercise duration,and frequency. OBJECTIVE:Comparing the brainstem auditory evoked potential of students studying folk dance to students studying other subjects.DESIGN:Observational contrast study. SETTING:Physical Education College,Shandong Normal University PARTICIPANTS:Fifty-five female students were enrolled at Shandong Normal University between September and December in 2005,including 21 students that studied folk dance and 34 students that studied other subjects.The age of the folk dance students averaged(19±1)years and dance training length was(6.0 ±1.5)years.The students that studied other subjects had never taken part in dance training or other physical training,and their age averaged(22±1)years,body height averaged(162±5)cm,body mass averaged(51 ±6)kg.All subjects had no prior ear disease or history of other neurological disorders.All students provided informed consent for the experimental project. METHODS:The neural electricity tester,NDI-200(Shanghai Poseidon Medical Electronic Instrument Factory)was used to examine and record Brainstem Auditory Evoked Potential values of the subjects during silence,as well as to transversally analyze the Brainstem Auditory Evoked Potential values.The electrode positions were cleaned and degreased with soapy water,followed by ethanol.The selected bipolar electrodes were situated on the head:recording electrodes were placed at the Baihui acupoint,and the reference electrode was placed at the mastoid of the measured ear,with grounding electrodes in the center of the forehead.Brainstem Auditory Evoked Potential values were elicited by monaural stimulation of a "click" though an earphone; the other ear was sheltered by the white noise.The click intensity was 102 db,the stimulation frequency was 30 Hz,the bandpass filters were 1 000-3 000 Hz,the sensitivity was 5 μV,and a total of 2 000 sweeps were

  20. Ocular vestibular evoked myogenic potential in patients with benign paroxysmal positional vertigo

    Directory of Open Access Journals (Sweden)

    Mozhgan Masoom

    2014-06-01

    Full Text Available Background and Aim: Since utricle is the main damaged organ in benign paroxysmal positional vertigo (BPPV, ocular vestibular evoked myogenic potential (oVEMP may be an appropriate method to evaluate the utricule dysfunction and the effect of disease recurrence rate on it. This study aimed to record myogenic potential in patients with benign paroxysmal positional vertigo.Methods: In a cross-sectional study, ocular myogenic potential was recorded in 25 healthy subjects and 20 patients with benign paroxysmal positional vertigo using 500 Hz-tone bursts (95 dB nHL.Results: In the affected ear, mean amplitude was lower and mean threshold was higher than those in the unaffected ear and in the normal group (p<0.05. Mean amplitude asymmetry ratio of patients was more than the healthy subjects (p0.05. Frequencies of abnormal responses in the affected ears were higher than in unaffected ears and in the normal group (p<0.05. Furthermore, the patients with recurrent vertigo showed more abnormalities than the patients with non-recurrent (p=0.030.Conclusion: In the recurrent benign paroxysmal positional vertigo, ocular vestibular evoked myogenic potential showed more damage in the utricle, suggesting this response could be used to evaluate the patients with benign paroxysmal positional vertigo.

  1. Flash visual evoked potential monitoring of optic tract function during macroelectrode-based pallidotomy.

    Science.gov (United States)

    Bonaroti, E A; Rose, R D; Kondziolka, D; Baser, S; Lunsford, L D

    1997-03-15

    Posteroventral pallidotomy (PVP) has received renewed interest as an ablative procedure for the symptomatic treatment of Parkinson's disease. In previous reports, the proximity of the optic tract to the lesion target in the globus pallidus internus has resulted in the occurrence of visual field deficits in as much as 14% of patients. The authors have used intraoperative visual evoked potentials (VEPs) during PVP to reduce this risk. All procedures were performed in awake patients. Flash stimuli were delivered to each eye via fiberoptic sources. Baseline flash VEPs were recorded at O1/Cz (left visual cortex to vertex), Oz/Cz (midline visual cortex to vertex), and O2/Cz (right visual cortex to vertex) for OS, OU, and OD stimulation. Epochs were acquired before and after localization, after macroelectrode stimulation, after temporary thermal lesioning, and after permanent thermal lesioning. Forty-seven patients underwent a total of 59 procedures. Visual evoked potentials were recorded reproducibly in all patients. In 11 procedures, VEP changes were reported, including six amplitude changes (10-80%), six latency shifts (3-10 msec), and one report of "variability." In four procedures, VEP changes prompted a change in target coordinates. One false-positive and one false-negative VEP change were encountered. The only confirmed visual deficit was a superior quadrantanopsia, present on formal fields, but clinically asymptomatic. The authors conclude that VEPs may be useful for procedures performed in the awake patient because of the lack of anesthetic-induced variability. The 1.7% visual morbidity reported here (one in 59 patients) compares favorably with other series using microelectrodes. Visual evoked potentials may be a useful monitoring technique to reduce the incidence of clinically significant visual morbidity during pallidotomy, especially during formal lesioning of the ventral pallidum adjacent to the optic tract.

  2. Steady State Visual Evoked Potential Based Brain-Computer Interface for Cognitive Assessment

    DEFF Research Database (Denmark)

    Westergren, Nicolai; Bendtsen, Rasmus L.; Kjær, Troels W.;

    2016-01-01

    decline is important. Cognitive decline may be detected using fullyautomated computerized assessment. Such systems will provide inexpensive and widely available screenings of cognitive ability. The aim of this pilot study is to develop a real time steady state visual evoked potential (SSVEP) based brain-computer...... interface (BCI) for neurological cognitive assessment. It is intended for use by patients who suffer from diseases impairing their motor skills, but are still able to control their gaze. Results are based on 11 healthy test subjects. The system performance have an average accuracy of 100% ± 0%. The test...

  3. Effect of Acupuncture on the Auditory Evoked Brain Stem Potential in Parkinson's Disease

    Institute of Scientific and Technical Information of China (English)

    王玲玲; 何崇; 刘跃光; 朱莉莉

    2002-01-01

    @@ Under the auditory evoked brain stem potential (ABP) examination, the latent period of V wave and the intermittent periods of III-V peak and I-V peak were significantly shortened in Parkinson's disease patients of the treatment group (N=29) after acupuncture treatment. The difference of cumulative scores in Webster's scale was also decreased in correlation analysis. The increase of dopamine in the brain and the excitability of the dopamine neurons may contribute to the therapeutic effects, in TCM terms, of subduing the pathogenic wind and tranquilizing the mind.

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

    OpenAIRE

    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...

  5. Evaluation of New Methods for Artifacts Rejection in Evoked Auditory Steady-State Potentials

    Directory of Open Access Journals (Sweden)

    Cyndi González Alfonso

    2014-11-01

    Full Text Available This paper presents two alternative methods to the traditional method of artifact rejectionequipment currently used in evoked potential recording steady state (ASSR in order to improveefficiency based on the use of a larger number of individual records. The first method proposedis to replace the traditional use of rejection threshold amplitude, while the second version is afaster implementation of the weighted averaging used today, which is applicable also in thetransient Auditory Brainstem Response (ABR. These changes have been made in order toimplement these methods in a real time microprocessor.

  6. Effect of epidural clonidine on somatosensory evoked potentials to dermatomal stimulation

    DEFF Research Database (Denmark)

    Lund, C; Hansen, O B; Kehlet, H

    1989-01-01

    The effect of lumbar epidural clonidine 150 micrograms on early (less than 0.5 s) somatosensory evoked potentials (SEP) to electrical stimulation of the L1 and S1 dermatomes was examined in twelve cancer patients. Epidural clonidine led to a minor but significant decrease in amplitude of two...... systolic and diastolic blood pressures decreased from 118 +/- 4/72 +/- 5 mmHg to 99 +/- 5/60 +/- 3 mmHg (P less than 0.01), respectively. It is concluded that epidural clonidine has a minor effect on the early SEPs to electrical dermatomal stimulation. Additionally, a pronounced effect on cancer pain...

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

    Science.gov (United States)

    Li, Wei; Li, Mengfan; Zhao, Jing

    2014-01-01

    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

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

    Science.gov (United States)

    Li, Wei; Li, Mengfan; Zhao, Jing

    2014-01-01

    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.

  9. Effects of carnosine on the evoked potentials in hippocampal CA1 region

    Institute of Scientific and Technical Information of China (English)

    Zhou-yan FENG; Xiao-jing ZHENG; Jing WANG

    2009-01-01

    Objective: To directly examine the effects of carnosine on neuronal excitation and inhibition in rat hippocampus in vivo. Methods: Artificial cerebrospinal fluid with carnosine was directly administrated over the exposed rat hippocampus. The changes of neuron activity in the CA1 region of hippocampus were evaluated by orthodromically- and antidromically-evoked potentials, as well as paired-pulse stimulation paradigm. Results: In both orthodromic and antidromic response potentials, carnosine transformed population spikes (PSs) with single spike into epileptiform multiple spikes. In addition, similar to the effect of γ-aminobutyric acidA (GABAA) antagonist picrotoxin, carnosine decreased paired-pulse stimulating depression significantly.However, no significant change was observed in the spontaneous field potentials during the application of carnosine. Conclusion:The results indicate a disinhibition-induced excitation effect of carnosine on the CA1 pyramidal neurons. It provides important information against the application of carnosine as a potential anticonvulsant in clinical treatment.

  10. Voltage-gated sodium channel expression and action potential generation in differentiated NG108-15 cells

    OpenAIRE

    Liu Jinxu; Tu Huiyin; Zhang Dongze; Zheng Hong; Li Yu-Long

    2012-01-01

    Abstract Background The generation of action potential is required for stimulus-evoked neurotransmitter release in most neurons. Although various voltage-gated ion channels are involved in action potential production, the initiation of the action potential is mainly mediated by voltage-gated Na+ channels. In the present study, differentiation-induced changes of mRNA and protein expression of Na+ channels, Na+ currents, and cell membrane excitability were investigated in NG108-15 cells. Result...

  11. INFLUENCE OF ACUPUNCTURE ("JIN'S SAN ZHEN") ON BRAINSTEM EVOKED POTENTIALS IN MENTAL RETARDATION CHILDREN

    Institute of Scientific and Technical Information of China (English)

    YUAN Qing; MA Ruiling; JIN Rui

    2002-01-01

    Objective: To investigate the effect of acupuncture ("JIN's San Zhen") on infantile mental retardation (MR) .Methods: 44 cases of MR children were attributed to treatment group and 39 normal children to control group.P3(event-related potential) and brainstem evoked potentials were used as the indexes. Acupoints "Si-shen Zhen","Head Zhi San Zhen", "Hand Zhi San Zhen", "Foot Zhi San Zhen" were punctured with filiform needles, and stimulated by manipulating the needle once every 5 minutes with uniform reinforcing-reducing method. The treatment was conducted once daily, 6 times every week, with 4 months being a therapeutic course. Results: In comparison with normal children, the latency of P3 was longer and its amplitude lower in MR children. After 4 months' acupuncture treatment,the latency was shortened and the amplitude increased significantly in comparison with pre-treatment ( P<0.01,0.05). Results of the total inteiiigence quotient (TIQ) evaluation showed a 70.3% coincidence rate compared with improvement of P3. Conclusion: Changes of P3 and BAEP(brain auditory evoked potential) after acupuncture treatment may be related to the effect of "JIN's San Zhen" in bettering clinical symptoms and signs of MR infantile patients.

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

    Science.gov (United States)

    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

  13. Bilaterally evoked monosynaptic EPSPs, NMDA receptors and potentiation in rat sympathetic preganglionic neurones in vitro.

    Science.gov (United States)

    Spanswick, D; Renaud, L P; Logan, S D

    1998-05-15

    1. Whole-cell patch clamp and intracellular recordings were obtained from 190 sympathetic preganglionic neurones (SPNs) in spinal cord slices of neonatal rats. Fifty-two of these SPNs were identified histologically as innervating the superior cervical ganglion (SCG) by the presence of Lucifer Yellow introduced from the patch pipette and the appearance of retrograde labelling following the injection of rhodamine-dextran-lysine into the SCG. 2. Electrical stimulation of the ipsilateral (n = 71) or contralateral (n = 32) lateral funiculi (iLF and cLF, respectively), contralateral intermediolateral nucleus (cIML, n = 41) or ipsilateral dorsal horn (DH, n = 34) evoked EPSPs or EPSCs that showed a constant latency and rise time, graded response to increased stimulus intensity, and no failures, suggesting a monosynaptic origin. 3. In all neurones tested (n = 60), fast rising and decaying components of EPSPs or EPSCs evoked from the iLF, cLF, cIML and DH in response to low-frequency stimulation (0.03-0.1 Hz) were sensitive to non-NMDA receptor antagonists. 4. In approximately 50 % of neurones tested (n = 29 of 60), EPSPs and EPSCs evoked from the iLF, cLF, cIML and DH during low-frequency stimulation were reduced by NMDA receptor antagonists. In the remaining neurones, an NMDA receptor antagonist-sensitive EPSP or EPSC was revealed only in magnesium-free bathing medium, or following high-frequency stimulation. 5. EPSPs evoked by stimulation of the iLF exhibited a sustained potentiation of the peak amplitude (25.3 +/- 11.4 %) in six of fourteen SPNs tested following a brief high-frequency stimulus (10-20 Hz, 0.1-2 s). 6. These results indicate that SPNs, including SPNs innervating the SCG, receive monosynaptic connections from both sides of the spinal cord. The neurotransmitter mediating transmission in some of the pathways activated by stimulation of iLF, cLF, cIML and DH is glutamate acting via both NMDA and non-NMDA receptors. Synaptic plasticity is a feature of

  14. TMS-induced motor evoked potentials in Wilson's disease: a systematic literature review.

    Science.gov (United States)

    Bembenek, Jan P; Kurczych, Katarzyna; Członkowska, Anna

    2015-04-01

    Wilson's disease (WD) is a metabolic brain disease resulting from improper copper metabolism. Although pyramidal symptoms are rarely observed, subclinical injury is highly possible as copper accumulates in all brain structures. The usefulness of motor evoked potentials (MEPs) in pyramidal tracts damage evaluation still appears to be somehow equivocal. We searched for original papers assessing the value of transcranial magnetic stimulation elicited MEPs with respect to motor function of upper and lower extremity in WD. We searched PubMed for original papers evaluating use of MEPs in WD using key words: "motor evoked potentials Wilson's disease" and "transcranial magnetic stimulation Wilson's disease." We found six articles using the above key words. One additional article and one case report were found while viewing the references lists. Therefore, we included eight studies. Number of patients in studies was low and their clinical characteristic was variable. There were also differences in methodology. Abnormal MEPs were confirmed in 20-70% of study participants. MEPs were not recorded in 7.6-66.7% of patients. Four studies reported significantly increased cortical excitability (up to 70% of patients). Prolonged central motor conduction time was observed in four studies (30-100% of patients). One study reported absent or prolonged central motor latency in 66.7% of patients. Although MEPs may be abnormal in WD, this has not been thoroughly assessed. Hence, further studies are indispensable to evaluate MEPs' usefulness in assessing pyramidal tract damage in WD.

  15. Hearing outcomes after loss of brainstem auditory evoked potentials during microvascular decompression.

    Science.gov (United States)

    Thirumala, Parthasarathy D; Krishnaiah, Balaji; Habeych, Miguel E; Balzer, Jeffrey R; Crammond, Donald J

    2015-04-01

    The primary aim of this paper is to study the pre-operative characteristics, intra-operative changes and post-operative hearing outcomes in patients after complete loss of wave V of the brainstem auditory evoked potential. We retrospectively analyzed the brainstem auditory evoked potential data of 94 patients who underwent microvascular decompression for hemifacial spasm at our institute. Patients were divided into two groups - those with and those without loss of wave V. The differences between the two groups and outcomes were assessed using t-test and chi-squared tests. In our study 23 (24%) patients out of 94 had a complete loss of wave V, with 11 (48%) patients experiencing transient loss and 12 (52%) patients experiencing permanent loss. The incidence of hearing loss in patients with no loss of wave V was 5.7% and 26% in patients who did experience wave V loss. The incidence of hearing change in patients with no loss of wave V was 12.6% and 30.43% in patients who did experience wave V loss. Loss of wave V during the procedure or at the end of procedure significantly increases the odds of hearing loss. Hearing change is a significant under-reported clinical condition after microvascular decompression in patients who have loss of wave V.

  16. Visual Evoked Potentials as a Readout of Cortical Function in Infants With Tuberous Sclerosis Complex.

    Science.gov (United States)

    Varcin, Kandice J; Nelson, Charles A; Ko, Jordan; Sahin, Mustafa; Wu, Joyce Y; Jeste, Shafali Spurling

    2016-02-01

    Tuberous sclerosis complex is an autosomal dominant genetic disorder that confers a high risk for neurodevelopmental disorders, such as autism spectrum disorder and intellectual disability. Studies have demonstrated specific delays in visual reception skills that may predict the development of autism spectrum disorder and intellectual disability. Based on evidence for alterations in the retinogeniculate pathway in animal models of tuberous sclerosis complex, we asked whether children with tuberous sclerosis complex demonstrate alterations in early visual processing that may undermine the development of higher-level visual behaviors. Pattern-reversal visual evoked potentials were recorded in infants with tuberous sclerosis complex (n = 16) and typically developing infants (n = 18) at 12 months of age. Infants with tuberous sclerosis complex demonstrated remarkably intact visual evoked potentials even within the context of intellectual disability and epilepsy. Infants with tuberous sclerosis complex show intact visual cortical processing, suggesting that delays in visually mediated behaviors in tuberous sclerosis complex may not be rooted in early visual processing deficits.

  17. Visual evoked potentials to an illusory change in brightness: the Craik-Cornsweet-O'Brien effect.

    Science.gov (United States)

    Suter, Steve; Crown, Nik

    2016-07-01

    Can brain electrical activity associated with the Craik-Cornsweet-O'Brien effect (CCOB) be identified in humans? Opposing luminance gradients met in the middle of a square image to create a luminance contrast-defined vertical border. The resulting rectangles on each side of the border were otherwise equiluminant, but appeared to differ in brightness, the CCOB effect. When the contrast gradients were swapped, the participants perceived darker and lighter rectangles trading places. This dynamic CCOB stimulus was reversed 1/s to elicit visual evoked potentials. The CCOB effect was absent in two control conditions. In one, the immediate contrast border, where the gradients met, was replaced by a dark vertical stripe; in the other, the outer segments of both rectangles, where the illusion would otherwise occur, were replaced by dark rectangles, leaving only the contrast-reversing gradients. Visual evoked potential components P1 and N2 were present for the CCOB stimuli, but not the control stimuli. Results are consistent with functional MRI and single unit evidence, suggesting that the brightness of the CCOB effect becomes dissociated from the luminance falling on the eye early in visual processing. These results favor explanations of brightness induction invoking rapid, early amplification of very low spatial-frequency information in the image to approximate natural scenes as opposed to a sluggish brightness adjustment spreading from the contrast border. PMID:27254394

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

    Science.gov (United States)

    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.

  19. Modeling neural correlates of auditory attention in evoked potentials using corticothalamic feedback dynamics.

    Science.gov (United States)

    Trenado, Carlos; Haab, Lars; Strauss, Daniel J

    2007-01-01

    Auditory evoked cortical potentials (AECP) are well established as diagnostic tool in audiology and gain more and more impact in experimental neuropsychology, neuro-science, and psychiatry, e.g., for the attention deficit disorder, schizophrenia, or for studying the tinnitus decompensation. The modulation of AECP due to exogenous and endogenous attention plays a major role in many clinical applications and has experimentally been studied in neuropsychology. However the relation of corticothalamic feedback dynamics to focal and non-focal attention and its large-scale effect reflected in AECPs is far from being understood. In this paper, we model neural correlates of auditory attention reflected in AECPs using corticothalamic feedback dynamics. We present a mapping of a recently developed multiscale model of evoked potentials to the hearing path and discuss for the first time its neurofunctionality in terms of corticothalamic feedback loops related to focal and non-focal attention. Our model reinforced recent experimental results related to online attention monitoring using AECPs with application as objective tinnitus decompensation measure. It is concluded that our model presents a promising approach to gain a deeper understanding of the neurodynamics of auditory attention and might be use as an efficient forward model to reinforce hypotheses that are obtained from experimental paradigms involving AECPs. PMID:18002948

  20. THE APPLICATION OF CORTICAL SOMATOSENSORY EVOKED POTENTIAL MONITORING IN CHILD SCOLIOSIS SURGERY

    Institute of Scientific and Technical Information of China (English)

    白斌; 王坤正; 同志勤; 刘文科; 宋金辉; 袁国莲

    2003-01-01

    Objective To study the application value of cortical somatosensory evoked potential (CSEP) monitoring in child scoliosis surgery. Methods In surgeries of fifty-one children with scoliosis, the CSEP changes were continuously recorded by evoked potential instrument. The operations were performed under the guidance of CSEP monitoring. Results Before propping and reshaping, the latencies and amplitudes in all cases had no change. During propping and reshaping, the latencies of all cases were slowly elongated, but all less than 10 percent. The amplitudes in 15 cases dropped to 55 percent, but returned to 80 percent 3-8 minutes after stopping the operations or partially loosening the propped rods at once. The amplitude in one case suddenly dropped to 37 percent and returned to 54 percent half an hour after loosening the propped rods at once and recovered to the normal range one day after operation. All cases got ideal orthopedic results and no one had neurological complications post operation. Conclusion CSEP can accurately monitor the spinal injury and has a great value in preventing the spinal injury in child scoliosis surgery.

  1. Can a finding of cervical vestibular evoked myogenic potentials contribute to vestibular migraine diagnostics?

    Directory of Open Access Journals (Sweden)

    Tihana Vešligaj

    2016-02-01

    Full Text Available Aim To investigate differences in vestibular evoked myogenic potentials (VEMP results with patients suffering from vestibular migraine and healthy people, taking into consideration values of threshold and latency of occurrence of the characteristic wave complex, size of amplitude, and interaural amplitude ratio. According to the results, determine the importance and usefulness of VEMP in vestibular migraine diagnostics. Methods A total number of 62 subjects were included in the study, 32 of them belonging to a group of patients suffering from vestibular migraine (VM, while other 30 were in a control group of healthy subjects. Information was collected during the diagnostic evaluation. General and otoneurological history of patients and bedside tests, audiological results, videonystagmography and cervical vestibular evoked myogenic potentials (cVEMP were made. Results There was a difference in an interaural ratio of amplitudes in the experimental and control groups, but it was not found to be clinically significant. By ToneBurst 500 Hz method, the interaural amplitude ratio higher than 35% was measured in 46.97% subjects, while the response was totally unilaterally missing in 28.8% patients. Conclusion Even the sophisticated method as cVEMP does not give the ultimate result confirming the vestibular migraine diagnosis, and neither do other diagnostic methods. cVEMP result can contribute to the completion of full mosaic of vestibular migraine diagnostics.

  2. Defensiveness, anxiety and the amplitude/intensity function of auditory-evoked potentials.

    Science.gov (United States)

    Kline, J P; Schwartz, G E; Fitzpatrick, D F; Hendricks, S E

    1993-07-01

    This study measured relationships between defensiveness, anxiety, and auditory-evoked potentials to tones of varied intensity. Subjects were designated as defensive if they scored > or = 7 on the L-scale of the Eysenck Personality Questionnaire, and high-anxious if they scored > or = 11 on the N-scale. Four groups resulted: 'high anxious', 'defensive high anxious', 'repressors' (i.e., defensive low anxious) and 'low anxious'. Evoked potentials were recorded from FZ, CZ, PZ, C3, C4, T3 and T4, referenced to linked ears in response to 74, 84, 94 and 104 dB SPL tones. High-defensive subjects showed lower P2 amplitudes to the 94 and 104 dB tones and lower amplitude/intensity slopes at FZ, CZ, C3 and C4. High-anxious subjects showed lower P2 amplitudes to all four stimulus intensities at FZ, CZ and PZ. The results are consistent with the hypothesis that defensiveness is associated with desensitization to intense or painful stimulation. PMID:8407437

  3. Are flash-evoked visual potentials useful for intraoperative monitoring of visual pathway function?

    Science.gov (United States)

    Cedzich, C; Schramm, J; Fahlbusch, R

    1987-11-01

    Flash-evoked visual potentials (VEPs) recorded from the scalp were used in a series of 35 patients with tumors along the visual pathway: 3 orbital tumors, 25 perisellar tumors, 4 intraventricular tumors, and 3 occipital lesions. Preoperatively, various combinations of impaired visual fields and visual acuity were observed in over 90% of the patients. A postoperative decrease in visual function was observed in 3 cases. Of the 25 perisellar lesions, 13 were operated through a standard frontotemporal craniotomy and 12 were operated through a transnasal-transsphenoidal approach. VEPs were highly susceptible to volatile anesthetics, and there was a significant incidence of spontaneous latency increases and amplitude decreases in a large number of patients. There was an unacceptably high number of cases with significant VEP alteration occurring without concomitant visual function change. During trepanation or the transnasal approach, a reversible potential loss was observed in 11 patients, a profoundly altered wave form was seen in 8 cases, and a loss of single peaks was observed in 15 patients. During dissection of the tumor, a reversible potential loss or a potential with unidentifiable peaks was found in 25 cases; however, the VEPs recovered during closure or in the recovery room. There was no correlation between intraoperative VEP changes and the postoperative changes in visual function. In only 1 patient with an insignificant postoperative decrease in visual acuity from 0.4 to 0.3 was there a concomitant intraoperative potential loss. The major conclusion of our findings is that light-emitting diode flash-evoked VEPs demonstrate intraoperative changes that appear too early and too prominently to be caused solely by manipulation of the optic pathways.(ABSTRACT TRUNCATED AT 250 WORDS)

  4. Functional mapping of the sensorimotor cortex: combined use of magnetoencephalography, functional MRI, and motor evoked potentials

    Energy Technology Data Exchange (ETDEWEB)

    Morioka, T. [Dept. of Neurosurgery, Neurological Inst., Kyshu Univ., Fukuoka (Japan); Fujii, K. [Dept. of Neurosurgery, Neurological Inst., Kyshu Univ., Fukuoka (Japan); Fukui, M. [Dept. of Neurosurgery, Neurological Inst., Kyshu Univ., Fukuoka (Japan); Mizushima, A. [Dept. of Radiology, Kyushu Univ. Fukuoka (Japan); Matsumoto, S. [Dept. of Radiology, Kyushu Univ. Fukuoka (Japan); Hasuo, K. [Dept. of Radiology, Kyushu Univ. Fukuoka (Japan); Yamamoto, T. [Dept. of Otolaryngology, Kyushu Univ. Fukuoka (Japan); Tobimatsu, S. [Dept. of Clinical Neurophysiology, Neurological Inst., Kyushu Univ., Fukuoka (Japan)

    1995-10-01

    Combined use of magnetoencephalography (MEG), functional magnetic resonance imaging (f-MRI), and motor evoked potentials (MEPs) was carried out on one patient in an attempt to localise precisely a structural lesion to the central sulcus. A small cyst in the right frontoparietal region was thought to be the cause of generalised seizures in an otherwise asymptomatic woman. First the primary sensory cortex was identified with magnetic source imaging (MSI) of somatosensory evoked magnetic fields using MEG and MRI. Second, the motor area of the hand was identified using f-MRI during handsqueezing. Then transcranial magnetic stimulation localised the hand motor area on the scalp, which was mapped onto the MRI. There was a good agreement between MSI, f-MRI and MEP as to the location of the sensorimotor cortex and its relationship to the lesion. Multimodality mapping techniques may thus prove useful in the precise localisation of cortical lesions, and in the preoperative determination of the best treatment for peri-rolandic lesions. (orig.)

  5. The investigation of intercostal Somatosensory Evoked Potentials in senile patients with diabetes

    Institute of Scientific and Technical Information of China (English)

    Xu lanping; pan yonghua; lu weihong; wu yue; zhou lichun

    2000-01-01

    Objective: To explove intercostal Somatosensory evoked potcntials(ISEP)and MEP,SEP,BAEP,ECoG,VEP in the evaluation on senile patients with DM Methods:fffth-tvo neurologialy normal subjects and 35 senile patients with clinic ally definited Dm were used in this inrestigation to general intercostal SEPs were studied.It is that the stimulation site for the fifth,seventh and nineth intercostal nervcs is at the anterior axillary line, whereas the third intercostal nerve is excited just lateral to the stemum. Result:.ISEP latency date(X+2.5SD),ISEP side to side analysis, T test of ISEP in normal compared with diabetes, β cell function in 35 senile patients with DM were compared with plasma glucose,Ralation between ISEP and other multimodal evoked potential,the abnormal rate of ISEP26 case .Respectively comparison of ISEP between DM patients with healths controlsexcept LN3 RN3 LN9 t=0.147-1.57,p=0.22-1.gl,the others were t=2.3-7.3,p=0. 000-0.02.The ISEPresult were comparedwith FPG, PPG、 HbAlc,disease duration,insulin. C peptid r=0.243-0.905,p=0.0l-0.05.Conclusion:ISEP could evaluate sternum lesions affecting the thoracic nerve roots disease,but also might be help in judging peripheral nerve disease with DM early diagnosis and predict the course of the disease.

  6. Frequency specificity of simultaneously recorded early and middle latency auditory evoked potentials.

    Science.gov (United States)

    Scherg, M; Volk, S A

    1983-11-01

    Early and middle latency auditory evoked potentials were recorded simultaneously with a 2-channel wide-band recording technique. Latency and amplitude distributions of components V, Na and Pa were determined in 20 normal hearing adults for 3 different stimuli (click, plop, 500 Hz tone burst) presented at 70, 30 and 20 dB HL. Normative latency data of the middle latency components are presented. The detectability and amplitude of the Na-Pa complex were considerably larger than those of wave V at 20 and 30 dB HL for the two low frequency stimuli. Ten ears exhibiting high frequency sensorineural hearing loss were examined. In these cases, only click-evoked Na and Pa, but not wave V, were observed down to 20 dB HL. Also, the click latency-intensity function of Na-Pa was found to be similar to the normal low frequency latency functions. The results consistently suggested that the low frequency contributions to wave V cancel in phase because of short duration, whereas the duration of the Na-Pa complex allows for a positive superimposition of all frequency bands. Since these differences in frequency specificity of the EAEP and the MAEP affect latency, care is advised for the interpretation of inter-peak latencies.

  7. Electroencephalogram and evoked potential parameters examined in Chinese mild head injury patients for forensic medicine

    Institute of Scientific and Technical Information of China (English)

    Xi-Ping CHEN; Lu-Yang TAO; Andrew CN CHEN

    2006-01-01

    Objective To evaluate the usefulness of quantitative electroencephalogram (QEEG), flash visual evoked potential (F-VEP) and auditory brainstem responses (ABR) as indicators of general neurological status. Methods Comparison was conducted on healthy controls (N=30) and patients with brain concussion (N=60) within 24 h after traumatic brain injury. Follow-up study of patient group was completed with the same standard paradigm 3 months later. All participants were recorded in multi-modality related potential testing in both early and late concussion at the same clinical setting. Glasgow coma scale, CT scanning, and physical examinations of neuro-psychological function, optic and auditory nervous system were performed before electroencephalogram (EEG) and evoked potential (EEG-EP) testing. Any participants showed abnormal changes of clinical examinations were excluded from the study. Average power of frequency spectrum and power ratios were selected for QEEG testing, and latency and amplitude of F-VEP and ABR were recorded.Results Between patients and normal controls, the results indicated: (1) Highly significance (P < 0.01) in average power of α1 and power ratios of θ/α1, θ/α2, α1/α2 of EEG recording; (2) N70-P100 amplitude of F-VEP in significant difference at early brain concussion; and (3) apparent prolongation of Ⅰ~Ⅲ inter-peak latency of ABR appeared in some individuals at early stage after concussion. The follow-up study showed that some patients with concussion were also afflicted with characteristic changes of EEG components for both increments of α1 average power and θ/α2 power ratio after 3 months recording. Conclusion EEG testing has been shown to be more effective and sensitive than evoked potential tests alone on detecting functional state of patients with mild traumatic brain injury (MTBI). Increments of α1 average power and θ/α2 power ratio are the sensitive EEG parameters to determining early concussion and evaluating outcome of

  8. Is the movement-evoked potential mandatory for movement execution? A high-resolution EEG study in a deafferented patient.

    Science.gov (United States)

    Kristeva, Rumyana; Chakarov, Vihren; Wagner, Michael; Schulte-Mönting, Jürgen; Hepp-Reymond, M-C

    2006-06-01

    During simple self-paced index finger flexion with and without visual feedback of the finger, we compared the movement-evoked potentials of the completely deafferented patient GL with those of 7 age-matched healthy subjects. EEG was recorded from 58 scalp positions, together with the electromyogram (EMG) from the first dorsal interosseous muscle and the movement trace. We analyzed the movement parameters and the contralateral movement-evoked potential and its source. The patient performed the voluntary movements almost as well as the controls in spite of her lack of sensory information from the periphery. In contrast, the movement-evoked potential was observed only in the controls and not in the patient. These findings clearly demonstrate that the movement-evoked potential reflects cutaneous and proprioceptive feedback from the moving part of the body. They also indicate that in absence of sensory peripheral input the motor control switches from an internal "sensory feedback-driven" to a "feedforward" mode. The role of the sensory feedback in updating the internal models and of the movement-evoked potential as a possible cortical correlate of motor awareness is discussed.

  9. [Determination of irreversibility of clinical brain death. Electroencephalography and evoked potentials].

    Science.gov (United States)

    Buchner, H; Ferbert, A

    2016-02-01

    Principally, in the fourth update of the rules for the procedure to finally determine the irreversible cessation of function of the cerebrum, the cerebellum and the brainstem, the importance of an electroencephalogram (EEG), somatosensory evoked potentials (SEP) and brainstem auditory evoked potentials (BAEP) are confirmed. This paper presents the reliability and validity of the electrophysiological diagnosis, discusses the amendments in the fourth version of the guidelines and introduces the practical application, problems and sources of error.An EEG is the best established supplementary diagnostic method for determining the irreversibility of clinical brain death syndrome. It should be noted that residual brain activity can often persist for many hours after the onset of brain death syndrome, particularly in patients with primary brainstem lesions. The derivation and analysis of an EEG requires a high level of expertise to be able to safely distinguish artefacts from primary brain activity. The registration of EEGs to demonstrate the irreversibility of clinical brain death syndrome is extremely time consuming.The BAEPs can only be used to confirm the irreversibility of brain death syndrome in serial examinations or in the rare cases of a sustained wave I or sustained waves I and II. Very often, an investigation cannot be reliably performed because of existing sound conduction disturbances or failure of all potentials even before the onset of clinical brain death syndrome. This explains why BAEPs are only used in exceptional cases.The SEPs of the median nerve can be very reliably derived, are technically simple and with few sources of error. A serial investigation is not required and the time needed for examination is short. For these reasons SEPs are given preference over EEGs and BAEPs for establishing the irreversibility of clinical brain death syndrome. PMID:26785843

  10. Dipole source analyses of laser evoked potentials obtained from subdural grid recordings from primary somatic sensory cortex

    OpenAIRE

    Baumgärtner, Ulf; Vogel, Hagen; Ohara, Shinji; Treede, Rolf-Detlef; Lenz, Fred

    2011-01-01

    The cortical potentials evoked by cutaneous application of a laser stimulus (laser evoked potentials, LEP) often include potentials in the primary somatic sensory cortex (S1), which may be located within the subdivisions of S1 including Brodmann areas 3A, 3B, 1, and 2. The precise location of the LEP generator may clarify the pattern of activation of human S1 by painful stimuli. We now test the hypothesis that the generators of the LEP are located in human Brodmann area 1 or 3A within S1. Loc...

  11. The effectiveness of FES-evoked EMG potentials to assess muscle force and fatigue in individuals with spinal cord injury.

    Science.gov (United States)

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

    2014-07-14

    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 SCI) population.

  12. Steady State Visual Evoked Potential Based Brain-Computer Interface for Cognitive Assessment

    DEFF Research Database (Denmark)

    Westergren, Nicolai; Bendtsen, Rasmus L.; Kjær, Troels W.;

    2016-01-01

    decline is important. Cognitive decline may be detected using fullyautomated computerized assessment. Such systems will provide inexpensive and widely available screenings of cognitive ability. The aim of this pilot study is to develop a real time steady state visual evoked potential (SSVEP) based brain-computer...... subjects achieved an information transfer rate (ITR) of 14:64 bits/min ± 7:63 bits=min and a subject test performance of 47:22% ± 34:10%. This study suggests that BCI may be applicable in practice as a computerized cognitive assessment tool. However, many improvements are required for the system...... interface (BCI) for neurological cognitive assessment. It is intended for use by patients who suffer from diseases impairing their motor skills, but are still able to control their gaze. Results are based on 11 healthy test subjects. The system performance have an average accuracy of 100% ± 0%. The test...

  13. Postoperative changes in visual evoked potentials and cognitive function tests following sevoflurane anaesthesia.

    LENUS (Irish Health Repository)

    Iohom, G

    2012-02-03

    We tested the hypothesis that minor disturbance of the visual pathway persists following general anaesthesia even when clinical discharge criteria are met. To test this, we measured visual evoked potentials (VEPs) in 13 ASA I or II patients who did not receive any pre-anaesthetic medication and underwent sevoflurane anaesthesia. VEPs were recorded on four occasions, before anaesthesia and at 30, 60, and 90 min after emergence from anaesthesia. Patients completed visual analogue scales (VAS) for sedation and anxiety, a Trieger Dot Test (TDT) and a Digit Symbol Substitution Test (DSST) immediately before each VEP recording. These results were compared using Student\\'s t-test. P<0.05 was considered significant. VEP latency was prolonged (P<0.001) and amplitude diminished (P<0.05) at 30, 60, and 90 min after emergence from anaesthesia, when VAS scores for sedation and anxiety, TDT, and DSST had returned to pre-anaesthetic levels.

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

    Directory of Open Access Journals (Sweden)

    Roy Schwartz

    2015-01-01

    Full Text Available 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.

  15. Cortical evoked potentials in response to rapid balloon distension of the rectum and anal canal

    DEFF Research Database (Denmark)

    Haas, S; Brock, C; Krogh, K;

    BACKGROUND: Neurophysiological evaluation of anorectal sensory function is hampered by a paucity of methods. Rapid balloon distension (RBD) has been introduced to describe the cerebral response to rectal distension, but it has not successfully been applied to the anal canal. METHODS: Nineteen...... healthy women received 30 RBDs in the rectum and the anal canal at intensities corresponding to sensory and unpleasantness thresholds, and response was recorded as cortical evoked potentials (CEPs) in 64-channels. The anal canal stimulations at unpleasantness level were repeated after 4 min to test...... the within-day reproducibility. CEPs were averaged, and to overcome latency variation related to jitter the spectral content of single sweeps was also computed. KEY RESULTS: Repeated stimulation of the anal canal generated CEPs with similar latencies but smaller amplitudes compared to those from the rectum...

  16. Cortical evoked potentials in response to rapid balloon distension of the rectum and anal canal

    DEFF Research Database (Denmark)

    Haas, S; Brock, C; Krogh, K;

    2014-01-01

    BACKGROUND: Neurophysiological evaluation of anorectal sensory function is hampered by a paucity of methods. Rapid balloon distension (RBD) has been introduced to describe the cerebral response to rectal distension, but it has not successfully been applied to the anal canal. METHODS: Nineteen...... healthy women received 30 RBDs in the rectum and the anal canal at intensities corresponding to sensory and unpleasantness thresholds, and response was recorded as cortical evoked potentials (CEPs) in 64-channels. The anal canal stimulations at unpleasantness level were repeated after 4 min to test...... the within-day reproducibility. CEPs were averaged, and to overcome latency variation related to jitter the spectral content of single sweeps was also computed. KEY RESULTS: Repeated stimulation of the anal canal generated CEPs with similar latencies but smaller amplitudes compared to those from the rectum...

  17. Magnetic resonance imaging compared with trimodal evoked potentials in possible multiple sclerosis

    International Nuclear Information System (INIS)

    Magnetic Resonance Imaging (MRI) of the brain and Evoked Potentials (EP) can both demonstrate the presence of clinically unsuspected demyelinating lesions and have proven to be sensitive (but not specific) in the diagnosis of multiple sclerosis (MS). MRI and EP are positive in 90 to 100% of patients with a definite diagnosis of MS. However, few studies have been conducted in patients with a lesser diagnostic certainty. In possible or suspected MS they gave conflicting results, possibly because of technical discrepancies and different clinical inclusion criteria. Since a number of putative new treatments can be evaluated in patients who have a definite diagnosis of MS, but nevertheless a short duration of disease and a low disability, it was decided to compare the sensitivity of MRI and EP as diagnostic tools in possible MS patients. MRI is shown to be more sensitive, shows more multiple lesions and gives a clearer appreciation of their size and exact location than EP. 10 refs.; 3 tabs

  18. Value of visual evoked potential monitoring during trans-sphenoidal pituitary surgery.

    Science.gov (United States)

    Chacko, A G; Babu, K S; Chandy, M J

    1996-06-01

    The visual outcome of 22 patients undergoing trans-sphenoidal excision of pituitary macroadenomas with intraoperative flash visual evoked potential (VEP) monitoring (Group A), was compared with a non-randomized group of 14 patients who had undergone similar operations without VEP monitoring (Group B). Tumour size, preoperative visual acuity, peripheral fields, and latencies and amplitudes of P1 and P2 were analysed to ascertain the best predictor of postoperative visual function. It was found that patients in Group A had a significantly greater improvement in field defects than those in Group B. There was no difference in postoperative improvement in visual acuity between the two groups. None of the variables analysed were good predictors of visual outcome.

  19. Ageing effect on air-conducted ocular vestibular evoked myogenic potential

    Directory of Open Access Journals (Sweden)

    Kaushlendra Kumar

    2015-08-01

    Full Text Available One of the recent diagnostic tests to assess the function of otolithic organs is through vestibular evoked myogenic potential (VEMP testing. There are equivocal findings on effect of aging on ocular VEMP (oVEMP parameters with reference to latencies. Hence this study was taken up to investigate the age related changes in oVEMP parameters. This present study considered 30 participants in each age group i.e., young adults, middle-aged adults and older adults. oVEMP were recorded using insert earphone at 100dBnHL at 500hZ short duration tone burst. The results showed in older adult significant difference in response rate, latencies and amplitude as compared to young and middle adult. Hence age should be taken into consideration when interpreting oVEMP results.

  20. Modulation of sensory inhibition of motor evoked potentials elicited by TMS prior to movement?

    DEFF Research Database (Denmark)

    Leukel, Christian; Lundbye-Jensen, Jesper; Nielsen, Jens Bo;

    Short latency afferent inhibition (SAI) refers to a decrement of the size of a motor evoked potential (MEP) by transcranial magnetic stimulation (TMS) after electrical stimulation of a peripheral afferent nerve (PNS) (Tokimura et al. 2000). Since SAI occurs when TMS is applied at the time...... to rest. In 9 healthy subjects (23 ± 3 years) MEPs were recorded in m. first dorsal interosseus (FDI) and m. abductor pollicis brevis (APB). To induce SAI, n. medianus was stimulated 20 ms prior to TMS over the motorcortex. In control trials, interstimulus intervals (ISIs) between afferent stimulation...... and TMS of 15, 25, 30, 35, and 40 ms were additionally tested. When moving, subjects were told to react to the afferent stimulus, and the delay between TMS and EMG onset was 343 ± 160 ms. When tested prior to movement, MEPs elicited with a delay of 20 ms after PNS were significantly greater (23 ± 9...

  1. Broad-Band Visually Evoked Potentials: Re(convolution in Brain-Computer Interfacing.

    Directory of Open Access Journals (Sweden)

    Jordy Thielen

    Full Text Available Brain-Computer Interfaces (BCIs allow users to control devices and communicate by using brain activity only. BCIs based on broad-band visual stimulation can outperform BCIs using other stimulation paradigms. Visual stimulation with pseudo-random bit-sequences evokes specific Broad-Band Visually Evoked Potentials (BBVEPs that can be reliably used in BCI for high-speed communication in speller applications. In this study, we report a novel paradigm for a BBVEP-based BCI that utilizes a generative framework to predict responses to broad-band stimulation sequences. In this study we designed a BBVEP-based BCI using modulated Gold codes to mark cells in a visual speller BCI. We defined a linear generative model that decomposes full responses into overlapping single-flash responses. These single-flash responses are used to predict responses to novel stimulation sequences, which in turn serve as templates for classification. The linear generative model explains on average 50% and up to 66% of the variance of responses to both seen and unseen sequences. In an online experiment, 12 participants tested a 6 × 6 matrix speller BCI. On average, an online accuracy of 86% was reached with trial lengths of 3.21 seconds. This corresponds to an Information Transfer Rate of 48 bits per minute (approximately 9 symbols per minute. This study indicates the potential to model and predict responses to broad-band stimulation. These predicted responses are proven to be well-suited as templates for a BBVEP-based BCI, thereby enabling communication and control by brain activity only.

  2. Low luminance/eyes closed and monochromatic stimulations reduce variability of flash visual evoked potential latency

    Directory of Open Access Journals (Sweden)

    Senthil Kumar Subramanian

    2013-01-01

    Full Text Available Context: Visual evoked potentials are useful in investigating the physiology and pathophysiology of the human visual system. Flash visual evoked potential (FVEP, though technically easier, has less clinical utility because it shows great variations in both latency and amplitude for normal subjects. Aim: To study the effect of eye closure, low luminance, and monochromatic stimulation on the variability of FVEPs. Subjects and Methods: Subjects in self-reported good health in the age group of 18-30 years were divided into three groups. All participants underwent FVEP recording with eyes open and with white light at 0.6 J luminance (standard technique. Next recording was done in group 1 with closed eyes, group 2 with 1.2 and 20 J luminance, and group 3 with red and blue lights, while keeping all the other parameters constant. Two trials were given for each eye, for each technique. The same procedure was repeated at the same clock time on the following day. Statistical Analysis: Variation in FVEP latencies between the individuals (interindividual variability and the variations within the same individual for four trials (intraindividual variability were assessed using coefficient of variance (COV. The technique with lower COV was considered the better method. Results: Recording done with closed eyes, 0.6 J luminance, and monochromatic light (blue > red showed lower interindividual and intraindividual variability in P2 and N2 as compared to standard techniques. Conclusions: Low luminance flash stimulations and monochromatic light will reduce FVEP latency variability and may be clinically useful modifications of FVEP recording technique.

  3. Rcpititative magnetic stimulation of gastrocnemius muscle evokes cerebral potentials in Duchcnnc muscular dystrophy

    Institute of Scientific and Technical Information of China (English)

    Cui Liying; Guan Yuzhou; Tang Xiaofu; Li Benhong

    2000-01-01

    OBJECTIVE: To study the function and mechanism of the ccrebral evoked potentials by repititative stimulation of calf muscle in Duchcnne mucular dystrophy (DMD) patients with obvious muscular dystrophy and pseudohyocrtrophy. METHODS: Wc measured cerebral cvoked potcntials by stimulation of calf muscles and SEP by stimulation of posterior tibial nerves at ankle in ten patients with DMD and ten normal controls matched with sex and age. The intensity of the magnetic stimulation was at 30% of maximal output (2.1 Tcsla) and the trcquency was I Hz. The low intensity of magnetic stimulation was just sufficient to produce a contraction of the muscle belly underncath the coil. Recording electrode was placed at 2 cm posterior to the Cz. referencc to Fpz. Thc latencics of N33. P38, N48 and P55 and amplitude (P38-N48) were recorded. SEP was recorded by routine methods. RESULTS: in normal subjects. thc amplitude of magnetic stimulation of calf muscle was 40% lower. and the latency of P38 was 2.9±2.1 ms longer compared with electrical stimulation of the posterior tibial nerves at ankle. In 6 patients. P38 latency from magnetic stimulation was remarkable prolonged (P<0.01). and in 4 patients. there no any response was found. SElP from electrical stimulation was normal in all patients. CONCLUSTION: DMD is an available model for the study of meclhanism of cerebral evoked potentials by magnetic stimulating muscles. Wc can coneludc that thc responses were produced by muscle input. The abnormal responses in patients may relate to decreased input of muscle by muscular dystrophy and pscudohypcrtrophy.

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

    Science.gov (United States)

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

    2014-09-01

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

  5. [Influence of GABA(C)-Receptor Antagonist on Formation of Evoked Potentials in Columns of the Rat Somatosensory Cortex].

    Science.gov (United States)

    Matukhno, A E; Lysenko, L V; Andreeva, Y V; Sukhov, A G

    2015-01-01

    Microelectrode studies of evoked potentials (EP) in neuronal column of rats barrel cortex show activating action of selective GABA(C)-receptor antagonist 1,2,5,6-tetrahydropyridin-4-yl-methylphosphinic acid (TPMPA) mainly on secondary components of EP of supragranular afferent layers of column compared to the efferent infragranular layers. These data suggest localization of GABA(C)-receptors on pre- synaptic terminals of thalamo-cortical glutamatergic afferents and ascending apical dendrites of pyramidal cells. A blockade of GABA(C)-receptors with the selective antagonist TPM PA leads to dose-dependent afferent depolarization with development of presynaptic inhibition and suppression of primary components of EP GABA(C)-receptors blocker produces different effects on secondary components of EP in supragranular layers of the cortex caused by the development of neuronal after hyperpolarization followed by high-amplitude primary response and afterdepolarization followed by low-amplitude primary responses with subsequent activation of different voltage-gated channels and formation of different level of cortical direct current potential gradients. PMID:26841661

  6. Recording evoked potentials during deep brain stimulation: development and validation of instrumentation to suppress the stimulus artefact

    Science.gov (United States)

    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

  7. THE MECHANISM OF CEREBRAL EVOKED POTENTIALS BY REPETITIVE MAGNETIC STIMULATION OF GASTROCNEMIUS MUSCLE IN DUCHENNE MUSCULAR DYSTROPHY

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Objective. To study the features and mechanism of the cerebral evoked potentials by repetitive stimulation of calf muscle in Duchenne muscular dystrophy (DMD) patients with obvious muscular dystrophy and psuedohypertrophy. Methods. Cerebral evoked potentials by stimulation of calf muscles and somatosensory evoked potentials (SEPs) by the stimulation of posterior tibial nerves at ankle were measured in 10 patients with DMD and 10 normal controls matched with gender and age. The intensity of the magnetic stimulation was at 30% of maximal output (2.1 Tesla, MagPro magnetic stimulator, Dantec) and the frequency was 1 Hz. The low intensity of magnetic stimulation was just sufficient to produce a contraction of the muscle belly underneath the coil. Recording electrode was placed at 2 cm posterior to the Cz, reference to Fpz. The latencies of N33, P38, N48 and P55 and amplitude (P38- N48) were recorded. SEPs were recorded by routine methods. Results. In normal subjects, the amplitudes of cerebral evoked potentials by magnetic stimulation of calf muscle was 40% lower than that by electrical stimulation of the posterior tibial nerves at ankle. The latency of P38 was 2.9± 2.1 ms longer compared with electrical stimulation of the posterior tibial nerves at ankle. In 6 patients, P38 latency from magnetic stimulation was remarkably prolonged (P<0.01), and in 4 patients, there was no remarkable response. SEPs evoked by electrical stimulation were normal in all of the patients.? Conclusion. DMD is an available model for the study of mechanism of cerebral evoked potentials by magnetic stimulating muscle. We can conclude that the responses from magnetic stimulation were produced by muscle input. The abnormal responses in patients may relate to decreased input of muscle by stimulating dystrophic and psedohypertrophic muscle.

  8. Evidence for the utricular origin of the vestibular short-latency-evoked potential (VsEP) to bone-conducted vibration in guinea pig.

    Science.gov (United States)

    Chihara, Yasuhiro; Wang, Vivian; Brown, Daniel J

    2013-08-01

    Previous studies have shown that the vestibular short-latency-evoked potential (VsEP) in response to the brief head acceleration stimulus is a compound action potential of neurons innervating the otolith organs. However, due to the lack of direct evidence, it is currently unclear whether the VsEP is primarily generated by the activity of utricular or saccular afferent neurons, or some mixture of the two. Here, we investigated the origin of the VsEP evoked by brief bone-conducted vibration pulses in guinea pigs, using selective destruction of the cochlea, semicircular canals (SCCs), saccule, or utricle, along with neural blockade with tetrodotoxin (TTX) application, and mechanical displacements of the surgically exposed utricular macula. To access each end organ, either a dorsal or a ventral surgical approach was used. TTX application abolished the VsEP, supporting the neurogenic origin of the response. Selective cochlear, SCCs, or saccular destruction had no significant effect on VsEP amplitude, whereas utricular destruction abolished the VsEP completely. Displacement of the utricular membrane changed the VsEP amplitude in a non-monotonic fashion. These results suggest that the VsEP evoked by BCV in guinea pigs represents almost entirely a utricular response. Furthermore, it suggests that displacements of the utricular macula may alter its response to bone-conduction stimuli.

  9. Effects of overt and covert attention on the steady-state visual evoked potential.

    Science.gov (United States)

    Walter, Sabrina; Quigley, Cliodhna; Andersen, Søren K; Mueller, Matthias M

    2012-06-21

    Flickering stimuli evoke an oscillatory brain response with the same frequency as the driving stimulus, the so-called steady-state visual evoked potential (SSVEP). SSVEPs are robust brain signals whose amplitudes are enhanced with attention and thus play a major role in the development and use of non-invasive Brain-Computer Interfaces (BCIs). We compared the modulation of SSVEP amplitudes when subjects directly gazed at a flickering array of static dots (overt attention) to when they covertly shifted attention to the dots keeping their eyes at central fixation. A discrimination task was performed at the attended location to ensure that subjects shifted attention as instructed. Horizontal eye movements (allowed in overt attention but to be avoided in covert attention) were monitored by the horizontal electrooculogram. Subjects' behavioural performance was significantly reduced in covert attention compared to overt attention. Correspondingly, attentional modulation of SSVEP amplitudes by overt attention was larger in magnitude than for covert attention. Overt attention also changed the topographical distribution of SSVEP amplitudes on the scalp. Stimuli elicited the largest amplitudes at central occipital electrodes when they were overtly attended and at contralateral parieto-occipital sites when they were covertly attended. Accordingly, source analysis revealed clear centrally located sources in early visual areas in overt attention, regardless of the attended visual hemifield. Taken together these results affirm that overt and covert attention have qualitatively and quantitatively different effects on SSVEP responses as well as on task performance. Moreover, our results suggest that navigating SSVEP-BCIs with overt attention is more reliable and highlight some of the challenges in developing BCIs for patients who have lost the ability to move their eyes.

  10. Giant early components of somatosensory evoked potentials to tibial nerve stimulation in cortical myoclonus.

    Science.gov (United States)

    Anzellotti, Francesca; Onofrj, Marco; Bonanni, Laura; Saracino, Antonio; Franciotti, Raffaella

    2016-01-01

    Enlarged cortical components of somatosensory evoked potentials (giant SEPs) recorded by electroencephalography (EEG) and abnormal somatosensory evoked magnetic fields (SEFs) recorded by magnetoencephalography (MEG) are observed in the majority of patients with cortical myoclonus (CM). Studies on simultaneous recordings of SEPs and SEFs showed that generator mechanism of giant SEPs involves both primary sensory and motor cortices. However the generator sources of giant SEPs have not been fully understood as only one report describes clearly giant SEPs following lower limb stimulation. In our study we performed a combined EEG-MEG recording on responses elicited by electric median and tibial nerve stimulation in a patient who developed consequently to methyl bromide intoxication CM with giant SEPs to median and tibial nerve stimuli. SEPs wave shapes were identified on the basis of polarity-latency components (e.g. P15-N20-P25) as defined by earlier studies and guidelines. At EEG recording, the SEP giant component did not appear in the latency range of the first cortical component for median nerve SEP (N20), but appeared instead in the range of the P37 tibial nerve SEP, which is currently identified as the first cortical component elicited by tibial nerve stimuli. Our MEG and EEG SEPs recordings also showed that components in the latency range of P37 were preceded by other cortical components. These findings suggest that lower limb P37 does not correspond to upper limb N20. MEG results confirmed that giant SEFs are the second component from both tibial (N43m-P43m) and median (N27m-P27m) nerve stimulation. MEG dipolar sources of these giant components were located in the primary sensory and motor area. PMID:27489768

  11. Gating of the vertex somatosensory and auditory evoked potential P50 and the correlation to skin conductance orienting response in healthy men

    DEFF Research Database (Denmark)

    Arnfred, S M; Eder, D N; Hemmingsen, R P;

    2001-01-01

    A defect in auditory evoked potential (AEP) P50 gating supports the theory of information-processing deficits in schizophrenia. The relationship between gating of the mid-latency evoked potentials (EP) in the somatosensory and the auditory modalities has not been studied together before. In schiz......A defect in auditory evoked potential (AEP) P50 gating supports the theory of information-processing deficits in schizophrenia. The relationship between gating of the mid-latency evoked potentials (EP) in the somatosensory and the auditory modalities has not been studied together before...

  12. Characteristic features of inhibitory junction potentials evoked by single stimuli in the guinea-pig isolated taenia caeci.

    Science.gov (United States)

    Bridgewater, M; Cunnane, T C; Brading, A F

    1995-05-15

    1. Changes in membrane potential of the guinea-pig isolated taenia caeci evoked by single stimuli have been investigated using intracellular recording techniques. Nifedipine (10 microM) was used to arrest spontaneous muscle action potentials. Single stimuli elicited complex junction potentials which consisted of both excitatory and inhibitory components. 2. The excitatory component of the compound junction potential was unaffected by hexamethonium (100 microM) but abolished by atropine (1 microM) and omega-conotoxin GVIA (10-100 nM). 3. In the presence of atropine, single stimuli elicited fast inhibitory junction potentials (IJPs). IJPs were sometimes biphasic during repolarization with a noticeable 'slow tail'. Apamin (30-100 nM) potently inhibited the fast IJP and revealed an underlying slow IJP. 4. The fast IJP was also abolished by omega-conotoxin GVIA (100 nM). However, the slow IJP was insensitive to omega-conotoxin GVIA but was abolished by cadmium (30 microM). 5. Guanethidine (3 microM) and N omega-nitro-L-arginine (10-100 microM) had no detectable effects on either of the IJPs. The dye Reactive Blue 2 reduced the amplitude of the fast IJP but this reduction was associated with a membrane hyperpolarization. 6. The existence of two distinct IJPs in the guinea-pig taenia caeci has been demonstrated. The ability of omega-conotoxin GVIA to selectively abolish the fast IJP leaving the slow IJP intact suggests that separate nerves are involved in mediating these responses.

  13. Long-latency auditory evoked potentials with verbal and nonverbal stimuli,

    Directory of Open Access Journals (Sweden)

    Sheila Jacques Oppitz

    2015-12-01

    Full Text Available ABSTRACT INTRODUCTION: Long-latency auditory evoked potentials represent the cortical activity related to attention, memory, and auditory discrimination skills. Acoustic signal processing occurs differently between verbal and nonverbal stimuli, influencing the latency and amplitude patterns. OBJECTIVE: To describe the latencies of the cortical potentials P1, N1, P2, N2, and P3, as well as P3 amplitude, with different speech stimuli and tone bursts, and to classify them in the presence and absence of these data. METHODS: A total of 30 subjects with normal hearing were assessed, aged 18-32 years old, matched by gender. Nonverbal stimuli were used (tone burst; 1000 Hz - frequent and 4000 Hz - rare; and verbal (/ba/ - frequent; /ga/, /da/, and /di/ - rare. RESULTS: Considering the component N2 for tone burst, the lowest latency found was 217.45 ms for the BA/DI stimulus; the highest latency found was 256.5 ms. For the P3 component, the shortest latency with tone burst stimuli was 298.7 with BA/GA stimuli, the highest, was 340 ms. For the P3 amplitude, there was no statistically significant difference among the different stimuli. For latencies of components P1, N1, P2, N2, P3, there were no statistical differences among them, regardless of the stimuli used. CONCLUSION: There was a difference in the latency of potentials N2 and P3 among the stimuli employed but no difference was observed for the P3 amplitude.

  14. Bilateral somatosensory evoked potentials following intermittent theta-burst repetitive transcranial magnetic stimulation

    Directory of Open Access Journals (Sweden)

    Ziluk Angela

    2010-08-01

    Full Text Available Abstract Background Intermittent theta-burst stimulation (iTBS is a form of repetitive transcranial magnetic stimulation that may alter cortical excitability in the primary somatosensory cortex (SI. The present study investigated the effects of iTBS on subcortical and early cortical somatosensory evoked potentials (SEPs recorded over left, iTBS stimulated SI and the right-hemisphere non-stimulated SI. SEPs were recorded before and at 5, 15, and 25 minutes following iTBS. Results Compared to pre-iTBS, the amplitude of cortical potential N20/P25 was significantly increased for 5 minutes from non-stimulated SI and for 15 to 25 minutes from stimulated SI. Subcortical potentials recorded bilaterally remained unaltered following iTBS. Conclusion We conclude that iTBS increases the cortical excitability of SI bilaterally and does not alter thalamocortical afferent input to SI. ITBS may provide one avenue to induce cortical plasticity in the somatosensory cortex.

  15. Theta burst repetitive transcranial magnetic stimulation attenuates somatosensory evoked potentials from the lower limb

    Directory of Open Access Journals (Sweden)

    Zapallow Christopher M

    2012-10-01

    Full Text Available Abstract Background Continuous theta burst stimulation (cTBS is a form of repetitive transcranial magnetic stimulation which has been shown to alter cortical excitability in the upper limb representation of primary somatosensory cortex (SI. However, it is unknown whether cTBS modulates cortical excitability within the lower limb representation in SI. The present study investigates the effects of cTBS over the SI lower limb representation on cortical somatosensory evoked potentials (SEPs and Hoffmann reflex (H-reflex following tibial nerve stimulation at the knee. SEPs and H-reflex were recorded before and in four time blocks up to 30 minutes following cTBS targeting the lower limb representation within SI. Results Following cTBS, the P1-N1 first cortical potential was significantly decreased at 12–16 minutes. CTBS also suppressed the P2-N2 second cortical potential for up to 30 minutes following stimulation. The H-reflex remained statistically unchanged following cTBS although there was a modest suppression observed. Conclusion We conclude that cTBS decreases cortical excitability of the lower limb representation of SI as evidenced by suppressed SEP amplitude. The duration and magnitude of the cTBS after effects are similar to those observed in upper limb studies.

  16. Correlation of action potentials in adjacent neurons

    CERN Document Server

    Shneider, M N

    2015-01-01

    A possible mechanism for the synchronization of action potential propagation along a bundle of neurons (ephaptic coupling) is considered. It is shown that this mechanism is similar to the salutatory conduction of the action potential between the nodes of Ranvier in myelinated axons. The proposed model allows us to estimate the scale of the correlation, i.e., the distance between neurons in the nervous tissue, wherein their synchronization becomes possible. The possibility for experimental verification of the proposed model of synchronization is discussed.

  17. Acute stress increases depolarization-evoked glutamate release in the rat prefrontal/frontal cortex: the dampening action of antidepressants.

    Directory of Open Access Journals (Sweden)

    Laura Musazzi

    Full Text Available BACKGROUND: Behavioral stress is recognized as a main risk factor for neuropsychiatric diseases. Converging evidence suggested that acute stress is associated with increase of excitatory transmission in certain forebrain areas. Aim of this work was to investigate the mechanism whereby acute stress increases glutamate release, and if therapeutic drugs prevent the effect of stress on glutamate release. METHODOLOGY/FINDINGS: Rats were chronically treated with vehicle or drugs employed for therapy of mood/anxiety disorders (fluoxetine, desipramine, venlafaxine, agomelatine and then subjected to unpredictable footshock stress. Acute stress induced marked increase in depolarization-evoked release of glutamate from synaptosomes of prefrontal/frontal cortex in superfusion, and the chronic drug treatments prevented the increase of glutamate release. Stress induced rapid increase in the circulating levels of corticosterone in all rats (both vehicle- and drug-treated, and glutamate release increase was blocked by previous administration of selective antagonist of glucocorticoid receptor (RU 486. On the molecular level, stress induced accumulation of presynaptic SNARE complexes in synaptic membranes (both in vehicle- and drug-treated rats. Patch-clamp recordings of pyramidal neurons in the prefrontal cortex revealed that stress increased glutamatergic transmission through both pre- and postsynaptic mechanisms, and that antidepressants may normalize it by reducing release probability. CONCLUSIONS/SIGNIFICANCE: Acute footshock stress up-regulated depolarization-evoked release of glutamate from synaptosomes of prefrontal/frontal cortex. Stress-induced increase of glutamate release was dependent on stimulation of glucocorticoid receptor by corticosterone. Because all drugs employed did not block either elevation of corticosterone or accumulation of SNARE complexes, the dampening action of the drugs on glutamate release must be downstream of these processes

  18. Screening action potentials: The power of light

    Directory of Open Access Journals (Sweden)

    Lars eKaestner

    2011-07-01

    Full Text Available Action potentials reflect the concerted activity of all electrogenic constituents in the plasma membrane during the excitation of a cell. Therefore, the action potential is an integrated readout and a promising parameter to detect electrophysiological failures or modifications thereof in diagnosis as well as in drug screens. Cellular action potentials can be recorded by optical approaches. To fulfill the pre-requirements to scale up for e.g. pharmacological screens the following preparatory work has to be provided: (i model cells under investigation need to represent target cells in the best possible manner; (ii optical sensors that can be either small molecule dyes or genetically encoded potential probes need to provide a reliable readout with minimal interaction with the naive behavior of the cells and (iii devices need to be capable to stimulate the cells, read out the signals with the appropriate speed as well as provide the capacity for a sufficient throughput. Here we discuss several scenarios for all three categories in the field of cardiac physiology and pharmacology and provide a perspective to use the power of light in screening cardiac action potentials.

  19. Intra-oral orthosis vs amitriptyline in chronic tension-type headache: a clinical and laser evoked potentials study

    Directory of Open Access Journals (Sweden)

    Sardaro Michele

    2006-05-01

    Full Text Available Abstract Background In the present study, we examined clinical and laser-evoked potentials (LEP features in two groups of chronic tension-type headache (CTTH patients treated with two different approaches: intra-oral appliance of prosthesis, aiming to reduce muscular tenderness, and 10 mg daily amitriptyline. Methods Eighteen patients with diagnosed CTTH participated in this open label, controlled study. A baseline evaluation was performed for clinical features, Total Tenderness Score (TTS and a topographic analysis of LEPs obtained manually and the pericranial points stimulation in all patients vs. healthy subjects. Thereafter, patients were randomly assigned to a two-month treatment by either amitriptyline or intra-oral appliance. Results and discussion Both the intra-oral appliance and amitriptyline significantly reduced headache frequency. The TTS was significantly reduced in the group treated with the appliance. The amplitude of P2 response elicited by stimulation of pericranial zones showed a reduction after amitriptyline treatment. Both therapies were effective in reducing headache severity, the appliance with a prevalent action on the pericranial muscular tenderness, amitriptyline reducing the activity of the central cortical structures subtending pain elaboration Conclusion The results of this study may suggest that in CTTH both the interventions at the peripheral and central levels improve the outcome of headache.

  20. Significance and cost-effectiveness of somatosensory evoked potential monitoring in cervical spine surgery

    Directory of Open Access Journals (Sweden)

    Ayoub Chakib

    2010-01-01

    Full Text Available Background : Intraoperative somatosensory evoked potential (SSEP monitoring during cervical spine surgery is not a universally accepted standard of care. Our retrospective study evaluated the efficacy and cost-effectiveness of intraoperative SSEP in a single surgeon′s practice. Materials and Methods : Intraoperative SSEP monitoring was performed on 210 consecutive patients who had cervical spine surgery: anterior cervical approach 140 and posterior approach 70. They were screened for degradation or loss of SSEP data. A cost analysis included annual medical costs for health and human services, durable goods and expendable commodities. Results : Temporary loss of the electrical wave during cauterization resolved upon discontinuation of the cautery. We had no loss of cortical wave with preservation of the popliteal potential. A drop in the amplitude of the cortical wave was observed in three patients. This drop was resolved after hemodynamic stabilization in the first patient, readjusting the bone graft in the second patient, and interrupting the surgery in the third patient. The additional cost for SSEP monitoring was $835 per case and the total cost of the surgery was $13,835 per case. By spending $31,546 per year on SSEP, our institution is saving a total cost ranging from $64,074 to $102,192 per patient injured per year. Conclusion : Intraoperative SSEP monitoring is a reliable and cost-effective method for preventing postoperative neurological deficit by the early detection of vascular or mechanical compromise, and the immediate alteration of the anesthetic or surgical technique.

  1. 3D graphics, virtual reality, and motion-onset visual evoked potentials in neurogaming.

    Science.gov (United States)

    Beveridge, R; Wilson, S; Coyle, D

    2016-01-01

    A brain-computer interface (BCI) offers movement-free control of a computer application and is achieved by reading and translating the cortical activity of the brain into semantic control signals. Motion-onset visual evoked potentials (mVEP) are neural potentials employed in BCIs and occur when motion-related stimuli are attended visually. mVEP dynamics are correlated with the position and timing of the moving stimuli. To investigate the feasibility of utilizing the mVEP paradigm with video games of various graphical complexities including those of commercial quality, we conducted three studies over four separate sessions comparing the performance of classifying five mVEP responses with variations in graphical complexity and style, in-game distractions, and display parameters surrounding mVEP stimuli. To investigate the feasibility of utilizing contemporary presentation modalities in neurogaming, one of the studies compared mVEP classification performance when stimuli were presented using the oculus rift virtual reality headset. Results from 31 independent subjects were analyzed offline. The results show classification performances ranging up to 90% with variations in conditions in graphical complexity having limited effect on mVEP performance; thus, demonstrating the feasibility of using the mVEP paradigm within BCI-based neurogaming.

  2. Cognitive Evoked Potential Measurement, P300, in a group of healthy Colombian individuals

    Directory of Open Access Journals (Sweden)

    Natalia Gutiérrez Giraldo

    2013-05-01

    Full Text Available Cognitive evoked potentials are electrophysiological measurements of cognitive functions. Cognitivepotential P300 is specifically related to attention processes. Objetive: the aim of this studywas to establish reference values for latency and amplitude of P300 wave in the Colombian population and determine their variability with age, gender and education of the subjects. Methods:we studied 122 healthy subjects between 6 and 80 years, are practical potential measurementmethodology as odd-ball, in leads Cz and Pz. Results: we were able to establish reference valuesfor different age groups, and statistical significance was found with which the latency of P300wave increases with the age of individuals, and instead thereof the amplitude tends to decrease.Similarly to correlate latency and amplitude was shown an inverse relationship between them.Conclusions: no differences were found for latency and wave amplitude, gender-related or schoolsubjects as well as no difference was found when measuring the Pz derivation obtained comparedwith the wave in lead Cz.

  3. Cortical Auditory Evoked Potentials in (Un)aided Normal-Hearing and Hearing-Impaired Adults.

    Science.gov (United States)

    Van Dun, Bram; Kania, Anna; Dillon, Harvey

    2016-02-01

    Cortical auditory evoked potentials (CAEPs) are influenced by the characteristics of the stimulus, including level and hearing aid gain. Previous studies have measured CAEPs aided and unaided in individuals with normal hearing. There is a significant difference between providing amplification to a person with normal hearing and a person with hearing loss. This study investigated this difference and the effects of stimulus signal-to-noise ratio (SNR) and audibility on the CAEP amplitude in a population with hearing loss. Twelve normal-hearing participants and 12 participants with a hearing loss participated in this study. Three speech sounds-/m/, /g/, and /t/-were presented in the free field. Unaided stimuli were presented at 55, 65, and 75 dB sound pressure level (SPL) and aided stimuli at 55 dB SPL with three different gains in steps of 10 dB. CAEPs were recorded and their amplitudes analyzed. Stimulus SNRs and audibility were determined. No significant effect of stimulus level or hearing aid gain was found in normal hearers. Conversely, a significant effect was found in hearing-impaired individuals. Audibility of the signal, which in some cases is determined by the signal level relative to threshold and in other cases by the SNR, is the dominant factor explaining changes in CAEP amplitude. CAEPs can potentially be used to assess the effects of hearing aid gain in hearing-impaired users. PMID:27587919

  4. Masculinizing effects on otoacoustic emissions and auditory evoked potentials in women using oral contraceptives.

    Science.gov (United States)

    McFadden, D

    2000-04-01

    The otoacoustic emissions (OAEs) and auditory evoked potentials (AEPs) measured in two separate large scale studies were examined retrospectively for potential differences between those women using, and those not using, oral contraception (OC). Fourteen dependent variables were examined, all of which exhibited substantial sex differences. For 13 of those 14 dependent variables, the means for the users of OC were shifted away from the means of the non-users in the direction of the males. Specifically, for four different measures of OAE strength, for seven of eight measures of AEP latency or amplitude, and for two cognitive tests (mental rotation and water level), the means for the users of OC were located intermediate to those of the non-users of OC and the males. Few of these differences between users and non-users of OC achieved statistical significance, but the near universality of the direction of the difference suggests that oral contraceptives do produce a weak masculinizing effect on some auditory structures. These weak masculinizing effects appear to run contrary to the facts that the levels of both free testosterone and estradiol are lower in women using OC than in normal-cycling women. Past findings on auditory sex differences may have underestimated those sex differences. PMID:10748325

  5. 3D graphics, virtual reality, and motion-onset visual evoked potentials in neurogaming.

    Science.gov (United States)

    Beveridge, R; Wilson, S; Coyle, D

    2016-01-01

    A brain-computer interface (BCI) offers movement-free control of a computer application and is achieved by reading and translating the cortical activity of the brain into semantic control signals. Motion-onset visual evoked potentials (mVEP) are neural potentials employed in BCIs and occur when motion-related stimuli are attended visually. mVEP dynamics are correlated with the position and timing of the moving stimuli. To investigate the feasibility of utilizing the mVEP paradigm with video games of various graphical complexities including those of commercial quality, we conducted three studies over four separate sessions comparing the performance of classifying five mVEP responses with variations in graphical complexity and style, in-game distractions, and display parameters surrounding mVEP stimuli. To investigate the feasibility of utilizing contemporary presentation modalities in neurogaming, one of the studies compared mVEP classification performance when stimuli were presented using the oculus rift virtual reality headset. Results from 31 independent subjects were analyzed offline. The results show classification performances ranging up to 90% with variations in conditions in graphical complexity having limited effect on mVEP performance; thus, demonstrating the feasibility of using the mVEP paradigm within BCI-based neurogaming. PMID:27590974

  6. A Brain Computer Interface for Robust Wheelchair Control Application Based on Pseudorandom Code Modulated Visual Evoked Potential

    DEFF Research Database (Denmark)

    Mohebbi, Ali; Engelsholm, Signe K.D.; Puthusserypady, Sadasivan;

    2015-01-01

    In this pilot study, a novel and minimalistic Brain Computer Interface (BCI) based wheelchair control application was developed. The system was based on pseudorandom code modulated Visual Evoked Potentials (c-VEPs). The visual stimuli in the scheme were generated based on the Gold code...

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

    Science.gov (United States)

    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…

  8. Stimulus-response characteristics of motor evoked potentials and silent periods in proximal and distal upper-extremity muscles.

    NARCIS (Netherlands)

    Kuijk, A.A. van; Anker, L.C.; Pasman, J.W.; Hendriks, J.C.M.; Elswijk, G.A.F. van; Geurts, A.C.H.

    2009-01-01

    OBJECTIVE: To compare stimulus-response characteristics of both motor evoked potentials (MEP) and silent periods (SP) induced by transcranial magnetic stimulation (TMS) in proximal and distal upper-extremity muscles. METHODS: Stimulus-response curves of MEPs and SPs were obtained from the biceps bra

  9. Slow late component in conditioned stimulus-evoked potentials from the amygdala after fear conditioning in the rat

    NARCIS (Netherlands)

    Knippenberg, J.M.J.; Luijtelaar, E.L.J.M. van; Maes, J.H.R.

    2003-01-01

    Male Wistar rats were subjected to a differential Pavlovian fear conditioning procedure in which one of two tones (6 or 10 kHz) was followed by an electric shock (CS+) and the other was not (CS-). Before and after fear cnditioning, we recorded the evoked potentials elicited by CS+ and CS- from elect

  10. Influence of the power-spectrum of the pre-stimulus EEG on the consecutive Auditory Evoked Potential in rats.

    NARCIS (Netherlands)

    Jongsma, M.L.A.; Quian Quiroga, R.; Rijn, C.M. van; Schaijk, W.J. van; Dirksen, R.; Coenen, A.M.L.

    2000-01-01

    Evoked Potentials (EPs) are responses that appear in the EEG due to external stimulation. Findings indicate that changes in EPs can be related to changes in frequencies of the pre-stimulus EEG. Auditory EPs of rats (n=8) were measured in reaction to tone-pip stimuli (90 dB, 10.2 kHz, ISI 2s, n=1500)

  11. Influence of the midbrain reticular formation irradiation with luminescent incoherent light on evoked potential of cerebral cortex in cats

    Science.gov (United States)

    Malinovskaya, Svetlana L.; Abakarov, Asadulla; Monich, Victor A.

    1996-11-01

    In acute experiments on cats it is shown, that direct, of- low-intensity incoherent light exposure on midbrain reticular formation, cases brain cortex projection areas functional state changes, which find expression in shifting amplitude of both positive and negative components of cortex evoked potentials on visual stimuli.

  12. Introducing the Action Potential to Psychology Students

    Science.gov (United States)

    Simon-Dack, Stephanie L.

    2014-01-01

    For this simple active learning technique for teaching, students are assigned "roles" and act out the process of the action potential (AP), including the firing threshold, ion-specific channels for ions to enter and leave the cell, diffusion, and the refractory period. Pre-post test results indicated that students demonstrated increased…

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

    Science.gov (United States)

    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

  14. Topography of synchronization of somatosensory evoked potentials elicited by stimulation of the sciatic nerve in rat

    Directory of Open Access Journals (Sweden)

    Xuefeng eQu

    2016-05-01

    Full Text Available Purpose: Traditionally, the topography of somatosensory evoked potentials (SEPs is generated based on amplitude and latency. However, this operation focuses on the physical morphology and field potential-power, so it suffers from difficulties in performing identification in an objective manner. In this study, measurement of the synchronization of SEPs is proposed as a method to explore brain functional networks as well as the plasticity after peripheral nerve injury. Method: SEPs elicited by unilateral sciatic nerve stimulation in twelve adult male Sprague-Dawley (SD rats in the normal group were compared with SEPs evoked after unilateral sciatic nerve hemisection in four peripheral nerve injured SD rats. The characterization of synchronized networks from SEPs was conducted using equal-time correlation, correlation matrix analysis, and comparison to randomized surrogate data. Eigenvalues of the correlation matrix were used to identify the clusters of functionally synchronized neuronal activity, and the participation index (PI was calculated to indicate the involvement of each channel in the cluster. The PI value at the knee point of the PI histogram was used as a threshold to demarcate the cortical boundary. Results: Ten out of the twelve normal rats showed only one synchronized brain network. The remaining two normal rats showed one strong and one weak network. In the peripheral nerve injured group, only one synchronized brain network was found in each rat. In the normal group, all network shapes appear regular and the network is largely contained in the posterior cortex. In the injured group, the network shapes appear irregular, the network extends anteriorly and posteriorly, and the network area is significantly larger. There are considerable individual variations in the shape and location of the network after peripheral nerve injury. Conclusion: The proposed method can detect functional brain networks. Compared to the results of the

  15. Changes of evoked potential in different hippocampal regions induced by electrostimulation at medial mamillary nucleus of rats

    Institute of Scientific and Technical Information of China (English)

    Xinxin Li; Lihong Shang; Liang Zhang; Fengzhi Cui

    2006-01-01

    BACKGROUND: Morphological data have shown that the most important afferent fibers of papillary body come from hippocampal structure.OBJECTIVE: To observe the changes of evoked potential in hippocampus and the significance after electrostimulation at medial mamillary nucleus.DESIGN: An observational control experiment.SETTING: Department of Physiology, Shenyang Medical College.MATERIALS: Twenty-three male or female Wistar rats, 3-4 months old, weighing 270-350 g, were provided by bhe animal room of Shenyang Medical College [the license number was scxk(Liao)2003-0016].METHODS: The Wistar rats were anaesthetized by intraperintoneal injection of 20% urethane (1 g/kg), tracheal intubation was also given. The self-made double-pole metal stimulating electrode with the point diameter of 1 mm was inserted into medial mamillary nucleus, the wanted hippocampal guidance spot was found within the rang of the hippocampal region at the same side of tee mamillary body range (CA1-CA4),inserted with same-core guidance electrode, a sole square-wave stimulation of wave wide 0.2 ms stimulated with electrodes at the applied intensity of 7-9 V, the evoked potential was induced through guidance electrodes, and then input to the ATAC-350 data-processing machine for memory showing wave processing, the memory recorded wave recording graph was separately drawn up by the X-Y recording instrument to observe the latency, time procedure and amplitude of the evoked potential in each hippocampal region of the rats and calculate the percentage of the evoked potential in each hippocampal region, Totally 78 guidance spots in hippocampus were recorded, including 30 positive reaction spots and 48 negative ones.MAIN OUTCOME MEASURES:① Latency,time procedure and amplitude of the evoked potentials in each hippocampal region of rats;② percentage of the evoked potentials in each hippocampal region;③ the wave shapes of the evoked potentials in each hippocampal region from different arrangement in the

  16. Nicotine receptor subtype-specific effects on auditory evoked oscillations and potentials.

    Directory of Open Access Journals (Sweden)

    Robert E Featherstone

    Full Text Available 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 α7 nicotine receptor antagonist methyllycaconitine (MLA the α4β4/α4β2 nicotine receptor antagonist dihydro-beta-erythroidine (DHβE, and the α4β2 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 DHβE blocked nicotine-induced enhancements in P20 amplitude. Conversely, MLA did not alter P20 amplitude either when presented alone or with nicotine. Administration of the α4β2 specific agonist AZD3480 did not alter any aspect of P20 response, suggesting that DHβE blocks the effects of nicotine through a non-α4β2 receptor specific mechanism. Nicotine and AZD3480 reduced N40 amplitude, which was blocked by both DHβE and MLA. Finally, nicotine significantly increased event-related gamma, as did AZD3480, while DHβE 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 DHβE sensitive mechanism, but suggests that this does not occur through

  17. Potentiation of K+-evoked catecholamine release in the cat adrenal gland treated with ouabain.

    Science.gov (United States)

    Garcia, A. G.; Garcia-Lopez, E.; Horga, J. F.; Kirpekar, S. M.; Montiel, C.; Sanchez-Garcia, P.

    1981-01-01

    1 A vigorous catecholamine secretory response was evoked by small increments (2-10 mM) of the extracellular concentration of K+ ([K+])o) in cat adrenal glands treated with ouabain (10(-4) M), and perfused with Krebs-bicarbonate solution at room temperature. 2 The secretory response depends on [K+]o; increments of [K+]o as small as 2 mM for 2 min evoked a clear secretory response; at 10-17.7 mM K+, the maximal secretory response was observed. In normal glands, not treated with ouabain, no increase of the rate of catecholamine output was observed by raising [K+]o up to 17.7 mM for 2 min. 3 The K+ secretory response was time-dependent, requiring at least 1 min to be initiated; on continued exposure to 10 mM [K+]o, the enhanced response remained for at least 1 h. 4 In low [Na+]o, the K+-secretory response was unchanged. However, in 0-Ca2+, high-Mg2+ solutions, or in the presence of D600, an organic Ca2+ antagonist, it was abolished. 5 The K+-induced secretory response was not altered in the presence of tetrodoxin or tetraethylammonium. 6 It is concluded that ouabain potentiated the catecholamine secretory response to raised [K+]o by increasing the amount of Ca2+ available to the secretory machinery through (a) mobilization of an enhanced pool of membrane-bound Ca2+, (b) activation of membrane Ca2+ inward current; or (c) decrease of intracellular Ca2+ buffering systems. The activation by ouabain of a membrane Na+-Ca2+ exchange system is not involved in this K+-secretory response. It is suggested that the plasma membrane ATPase enzyme system, by changing the affinity of its Ca2+ binding sites, might control the availability of this cation to the secretory machinery and, therefore, modulate catecholamine secretion in the adrenal gland. PMID:7296168

  18. Motor evoked potentials in standing and recumbent calves induced by magnetic stimulation at the foramen magnum.

    Science.gov (United States)

    Rijckaert, J; Pardon, B; Verryken, K; Van Ham, L; van Loon, G; Deprez, P

    2016-10-01

    The aims of this study were to determine reference values for magnetic motor evoked potentials (mMEPs) in calves and the influence of position during examination (standing or lateral recumbency). Reference values were determined using 41 healthy Holstein Friesian bull calves aged 1-10 months; standing and lateral recumbency were examined in 11 calves. Maximal magnetic stimulation was performed at the level of the foramen magnum with a magnetic field of 4 T at the coil surface. In standing position, distinct, reproducible mMEPs were obtained in all calves. Onset latency (LAT) (mean ± standard deviation) was significantly shorter in the thoracic limbs (34.4 ± 3.1 ms) than in the pelvic limbs (44.6 ± 3.0 ms). Amplitude (AMPL) was significantly higher in the thoracic limbs (3.7 ± 1.7 mV) than in the pelvic limbs (3.3 ± 1.7 mV) and significantly increased with body length. Age, body weight, height at the withers and rectal temperature had no significant association with LAT or AMPL, and no differences between left and right were noted. In the lateral position, only 64% of the calves showed responses in the four limbs; in these calves, LAT (29.7 ± 4.7 ms) and AMPL (3.0 ± 1.8 mV) in the thoracic limbs were significantly different from AMPL (47.0 ± 7.4 ms) and LAT (2.1 ± 2.1 mV) in the pelvic limbs. In conclusion, mMEPs in limb muscles can be evoked in calves by stimulation at the level of the foramen magnum. mMEPs are more difficult to obtain in lateral recumbency than in standing calves. PMID:27687949

  19. Stimulus Specificity of Brain-Computer Interfaces Based on Code Modulation Visual Evoked Potentials.

    Directory of Open Access Journals (Sweden)

    Qingguo Wei

    Full Text Available A brain-computer interface (BCI based on code modulated visual evoked potentials (c-VEP is among the fastest BCIs that have ever been reported, but it has not yet been given a thorough study. In this study, a pseudorandom binary M sequence and its time lag sequences are utilized for modulation of different stimuli and template matching is adopted as the method for target recognition. Five experiments were devised to investigate the effect of stimulus specificity on target recognition and we made an effort to find the optimal stimulus parameters for size, color and proximity of the stimuli, length of modulation sequence and its lag between two adjacent stimuli. By changing the values of these parameters and measuring classification accuracy of the c-VEP BCI, an optimal value of each parameter can be attained. Experimental results of ten subjects showed that stimulus size of visual angle 3.8°, white, spatial proximity of visual angle 4.8° center to center apart, modulation sequence of length 63 bits and the lag of 4 bits between adjacent stimuli yield individually superior performance. These findings provide a basis for determining stimulus presentation of a high-performance c-VEP based BCI system.

  20. Dynamic topography of visual evoked potentials and extrageniculate projection in case of Riddoch phenomenon.

    Science.gov (United States)

    Tsutsui, J; Ichihashi, K; Kimura, H

    1984-01-01

    A 34-year-old woman showing the Riddoch phenomenon was studied by the technique of dynamic topography of visual evoked potential (VEP). This case had cortical blindness which developed during the process of massive intestinal hemorrhage, shock and surgery. The visual acuity was limited to hand movement, and perception of white and colored light was present, but there was no form recognition. Tracking eye movement for a flashlight was possible and optokinetic nystagmus (OKN) also appeared. CT-scan showed a diffuse low density area in the white matter of the occipital lobe. The VEPs by flash and a checkerboard of 60'-100' were detectable. Dynamic topography of the VEP showed that a strong negative deflection from the brainstem appeared at around 30 msec and this deflection expanded to the parietal region at about 90 msec. Subsequently, a positive deflection extending from the frontal region to the occipital region continued at 100 msec to 150 msec. Such a process of reaction is not observed in the normal subject. These findings suggest that the visual reaction was conducted abnormally through the extrageniculate system; from the brainstem to the parietal area and then to the occipital area. PMID:6748358

  1. EXPERIMENTAL AND CLINICAL STUDY ON BILIRUBIN NEUROTOXICITY DETECTED BY VISUAL EVOKED POTENTIALS TO FLASH

    Institute of Scientific and Technical Information of China (English)

    贲晓明; 秦玉明; 吴圣楣; 张惠民; 陈舜年; 夏振炜

    2001-01-01

    Objective Evaluate the sensitivity and reliability of visual evoked potential to flash ( FVEP ) in detecting bilirubin neurotoxicity and approach the risk parameters of bilirubin neurotoxicity in hyperbilirubinernia newborns. Methods Based on the successful establishment of animal models for acute bilirubin encephalopathy by intraperitoneal infusion of bilirubin with a dosage of 100~200μg /g body weight to 1-weekold guinea pigs, the F-VEP was recorded in animal models and human neonates with hyperbilirubinemia, and the sensitivity and reliability of F-VEP in detecting bilirubin neurotoxicity were evaluated. Results F-VEP features and its P1 latency significantly correlated to brain adenosine triphosphate (ATP) level, neurobehavioral and neuropathological changes in experimental bilirubin encephalopathy ; neonates with hyperbilirubinemia showed significant F-VEP changes characterized by absence of P1 or P1 latency prolonged in 1~7-dayold newborns, especially when the jaundice was caused by immunoincompatibility and infectious diseases. Conclusion F-VEP would be a good discriminator for bilirubin neurotoxicity, and can become a promising technique in monitoring bilirubin encephalopathy.

  2. Repetitive magnetic stimulation affects the microenvironment of nerve regeneration and evoked potentials after spinal cord injury

    Institute of Scientific and Technical Information of China (English)

    Jin-lan Jiang; Xu-dong Guo; Shu-quan Zhang; Xin-gang Wang; Shi-feng Wu

    2016-01-01

    Repetitive magnetic stimulation has been shown to alter local blood flow of the brain, excite the corticospinal tract and muscle, and induce motor function recovery. We established a rat model of acute spinal cord injury using the modiifed Allen’s method. After 4 hours of injury, rat models received repetitive magnetic stimulation, with a stimulus intensity of 35% maximum output intensity, 5-Hz frequency, 5 seconds for each sequence, and an interval of 2 minutes. This was repeated for a total of 10 sequences, once a day, 5 days in a week, for 2 consecutive weeks. After repetitive magnetic stimulation, the number of apoptotic cells decreased, matrix metalloproteinase 9/2 gene and protein expression decreased, nestin expression increased, somatosensory and motor-evoked potentials recovered, and motor function recovered in the injured spinal cord. These ifndings conifrm that repetitive magnetic stimulation of the spinal cord improved the microen-vironment of neural regeneration, reduced neuronal apoptosis, and induced neuroprotective and repair effects on the injured spinal cord.

  3. Diffusion tensor imaging of the inferior colliculus and brainstem auditory-evoked potentials in preterm infants

    Energy Technology Data Exchange (ETDEWEB)

    Reiman, Milla; Lehtonen, Liisa; Lapinleimu, Helena [Turku University Central Hospital, Department of Paediatrics, Turku (Finland); Parkkola, Riitta [Turku University Central Hospital, Department of Radiology and Turku PET Centre, Turku (Finland); Johansson, Reijo [Turku University Central Hospital, Department of Otorhinolaryngology, Turku (Finland); Jaeaeskelaeinen, Satu K. [Turku University Central Hospital, Department of Clinical Neurophysiology, Turku (Finland); Kujari, Harry [Turku University Central Hospital, Department of Pathology, Turku (Finland); Haataja, Leena [Turku University Central Hospital, Department of Paediatric Neurology, Turku (Finland)

    2009-08-15

    Preterm and low-birth-weight infants have an increased risk of sensorineural hearing loss. Brainstem auditory-evoked potentials (BAEP) are an effective method to detect subtle deficits in impulse conduction in the auditory pathway. Abnormalities on diffusion tensor imaging (DTI) have been shown to be associated with perinatal white-matter injury and reduced fractional anisotropy (FA) has been reported in patients with sensorineural hearing loss. To evaluate the possibility of a correlation between BAEP and DTI of the inferior colliculus in preterm infants. DTI at term age and BAEP measurements were performed on all very-low-birth-weight or very preterm study infants (n=56). FA and apparent diffusion coefficient (ADC) of the inferior colliculus were measured from the DTI. Shorter BAEP wave I, III, and V latencies and I-III and I-V intervals and higher wave V amplitude correlated with higher FA of the inferior colliculus. The association between the DTI findings of the inferior colliculus and BAEP responses suggests that DTI can be used to assess the integrity of the auditory pathway in preterm infants. (orig.)

  4. Interaction of Musicianship and Aging: A Comparison of Cortical Auditory Evoked Potentials

    Directory of Open Access Journals (Sweden)

    Jennifer L. O’Brien

    2015-01-01

    Full Text Available Objective. The goal of this study was to begin to explore whether the beneficial auditory neural effects of early music training persist throughout life and influence age-related changes in neurophysiological processing of sound. Design. Cortical auditory evoked potentials (CAEPs elicited by harmonic tone complexes were examined, including P1-N1-P2, mismatch negativity (MMN, and P3a. Study Sample. Data from older adult musicians (n=8 and nonmusicians (n=8 (ages 55–70 years were compared to previous data from young adult musicians (n=40 and nonmusicians (n=20 (ages 18–33 years. Results. P1-N1-P2 amplitudes and latencies did not differ between older adult musicians and nonmusicians; however, MMN and P3a latencies for harmonic tone deviances were earlier for older musicians than older nonmusicians. Comparisons of P1-N1-P2, MMN, and P3a components between older and young adult musicians and nonmusicians suggest that P1 and P2 latencies are significantly affected by age, but not musicianship, while MMN and P3a appear to be more sensitive to effects of musicianship than aging. Conclusions. Findings support beneficial influences of musicianship on central auditory function and suggest a positive interaction between aging and musicianship on the auditory neural system.

  5. A lower limb exoskeleton control system based on steady state visual evoked potentials

    Science.gov (United States)

    Kwak, No-Sang; Müller, Klaus-Robert; Lee, Seong-Whan

    2015-10-01

    Objective. We have developed an asynchronous brain-machine interface (BMI)-based lower limb exoskeleton control system based on steady-state visual evoked potentials (SSVEPs). Approach. By decoding electroencephalography signals in real-time, users are able to walk forward, turn right, turn left, sit, and stand while wearing the exoskeleton. SSVEP stimulation is implemented with a visual stimulation unit, consisting of five light emitting diodes fixed to the exoskeleton. A canonical correlation analysis (CCA) method for the extraction of frequency information associated with the SSVEP was used in combination with k-nearest neighbors. Main results. Overall, 11 healthy subjects participated in the experiment to evaluate performance. To achieve the best classification, CCA was first calibrated in an offline experiment. In the subsequent online experiment, our results exhibit accuracies of 91.3 ± 5.73%, a response time of 3.28 ± 1.82 s, an information transfer rate of 32.9 ± 9.13 bits/min, and a completion time of 1100 ± 154.92 s for the experimental parcour studied. Significance. The ability to achieve such high quality BMI control indicates that an SSVEP-based lower limb exoskeleton for gait assistance is becoming feasible.

  6. Tibial somatosensory evoked potential can prognosticate for ambulatory function in subacute hemiplegic stroke.

    Science.gov (United States)

    Hwang, Pyoungsik; Sohn, Min Kyun; Kim, Cuk-Seong; Jee, Sungju

    2016-04-01

    Early prediction of expected recovery in stroke can help in planning appropriate medical and rehabilitation interventions. Recovery of ambulation is one of the essential endpoints in stroke rehabilitation. However, the correlation of somatosensory evoked potentials (SSEP) with clinical parameters and their predictive significance are not clearly defined. We aimed to examine the association between tibial nerve SSEP and ambulatory outcomes in subacute hemiplegic stroke patients. We reviewed medical records for hemiplegic patients with first-ever stroke who received inpatient rehabilitation from January 2009 to May 2013. We excluded patients with diabetes mellitus, quadriplegia, bilateral lesions, brainstem lesions, those aged over 80 years, and those with severe musculoskeletal problems. Tibial nerve SSEP were performed when they were transferred to the rehabilitation department. SSEP findings were divided into three groups; normal, abnormal and absent response. Berg balance scale and functional ambulation category (FAC) at discharge were compared with initial tibial SSEP findings using one-way analysis of variance. Thirty-one hemiplegic patients were included. Berg balance scale and FAC were significantly different according to the SSEP (Phemiplegic patients.

  7. Spatiotemporal analysis of the cortical sources of the steady-state visual evoked potential.

    Science.gov (United States)

    Di Russo, Francesco; Pitzalis, Sabrina; Aprile, Teresa; Spitoni, Grazia; Patria, Fabiana; Stella, Alessandra; Spinelli, Donatella; Hillyard, Steven A

    2007-04-01

    This study aimed to characterize the neural generators of the steady-state visual evoked potential (SSVEP) to repetitive, 6 Hz pattern-reversal stimulation. Multichannel scalp recordings of SSVEPs and dipole modeling techniques were combined with functional magnetic resonance imaging (fMRI) and retinotopic mapping in order to estimate the locations of the cortical sources giving rise to the SSVEP elicited by pattern reversal. The time-varying SSVEP scalp topography indicated contributions from two major cortical sources, which were localized in the medial occipital and mid-temporal regions of the contralateral hemisphere. Colocalization of dipole locations with fMRI activation sites indicated that these two major sources of the SSVEP were located in primary visual cortex (V1) and in the motion sensitive (MT/V5) areas, respectively. Minor contributions from mid-occipital (V3A) and ventral occipital (V4/V8) areas were also considered. Comparison of SSVEP phase information with timing information collected in a previous transient VEP study (Di Russo et al. [2005] Neuroimage 24:874-886) suggested that the sequence of cortical activation is similar for steady-state and transient stimulation. These results provide a detailed spatiotemporal profile of the cortical origins of the SSVEP, which should enhance its use as an efficient clinical tool for evaluating visual-cortical dysfunction as well as an investigative probe of the cortical mechanisms of visual-perceptual processing.

  8. Attachment style moderates partner presence effects on pain: a laser-evoked potentials study.

    Science.gov (United States)

    Krahé, Charlotte; Paloyelis, Yannis; Condon, Heather; Jenkinson, Paul M; Williams, Steven C R; Fotopoulou, Aikaterini

    2015-08-01

    Social support is crucial for psychological and physical well-being. Yet, in experimental and clinical pain research, the presence of others has been found to both attenuate and intensify pain. To investigate the factors underlying these mixed effects, we administered noxious laser stimuli to 39 healthy women while their romantic partner was present or absent, and measured pain ratings and laser-evoked potentials (LEPs) to assess the effects of partner presence on subjective pain experience and underlying neural processes. Further, we examined whether individual differences in adult attachment style (AAS), alone or in interaction with the partner's level of attentional focus (manipulated to be either on or away from the participant) might modulate these effects. We found that the effects of partner presence vs absence on pain-related measures depended on AAS but not partner attentional focus. The higher participants' attachment avoidance, the higher pain ratings and N2 and P2 local peak amplitudes were in the presence compared with the absence of the romantic partner. As LEPs are thought to reflect activity relating to the salience of events, our data suggest that partner presence may influence the perceived salience of events threatening the body, particularly in individuals who tend to mistrust others.

  9. Attachment style moderates partner presence effects on pain: a laser-evoked potentials study.

    Science.gov (United States)

    Krahé, Charlotte; Paloyelis, Yannis; Condon, Heather; Jenkinson, Paul M; Williams, Steven C R; Fotopoulou, Aikaterini

    2015-08-01

    Social support is crucial for psychological and physical well-being. Yet, in experimental and clinical pain research, the presence of others has been found to both attenuate and intensify pain. To investigate the factors underlying these mixed effects, we administered noxious laser stimuli to 39 healthy women while their romantic partner was present or absent, and measured pain ratings and laser-evoked potentials (LEPs) to assess the effects of partner presence on subjective pain experience and underlying neural processes. Further, we examined whether individual differences in adult attachment style (AAS), alone or in interaction with the partner's level of attentional focus (manipulated to be either on or away from the participant) might modulate these effects. We found that the effects of partner presence vs absence on pain-related measures depended on AAS but not partner attentional focus. The higher participants' attachment avoidance, the higher pain ratings and N2 and P2 local peak amplitudes were in the presence compared with the absence of the romantic partner. As LEPs are thought to reflect activity relating to the salience of events, our data suggest that partner presence may influence the perceived salience of events threatening the body, particularly in individuals who tend to mistrust others. PMID:25556212

  10. Effect of higher frequency on the classification of steady-state visual evoked potentials

    Science.gov (United States)

    Won, Dong-Ok; Hwang, Han-Jeong; Dähne, Sven; Müller, Klaus-Robert; Lee, Seong-Whan

    2016-02-01

    Objective. Most existing brain-computer interface (BCI) designs based on steady-state visual evoked potentials (SSVEPs) primarily use low frequency visual stimuli (e.g., multiple LEDs flickering with low frequencies (6-14.9 Hz) with a duty-cycle of 50%, or higher frequencies (26-34.7 Hz) with duty-cycles of 50%, 60%, and 70%. The four different experimental conditions were tested with 26 subjects in order to investigate the impact of stimulation frequency and duty-cycle on performance and visual fatigue, and evaluated with a questionnaire survey. Resting state alpha powers were utilized to interpret our results from the neurophysiological point of view. Main results. The stimulation method employing higher frequencies not only showed less visual fatigue, but it also showed higher and more stable classification performance compared to that employing relatively lower frequencies. Different duty-cycles in the higher frequency stimulation conditions did not significantly affect visual fatigue, but a duty-cycle of 50% was a better choice with respect to performance. The performance of the higher frequency stimulation method was also less susceptible to resting state alpha powers, while that of the lower frequency stimulation method was negatively correlated with alpha powers. Significance. These results suggest that the use of higher frequency visual stimuli is more beneficial for performance improvement and stability as time passes when developing practical SSVEP-based BCI applications.

  11. Visual evoked potentials for intraoperative neurophysiologic monitoring using total intravenous anesthesia.

    Science.gov (United States)

    Wiedemayer, Helmut; Fauser, Barbara; Armbruster, W; Gasser, Thomas; Stolke, Dietmar

    2003-01-01

    Conflicting reports on the usefulness of intraoperative monitoring of visual function by means of visual evoked potentials (VEPs) initiated this study. In 32 patients without visual problems, VEPs were recorded to evaluate the reliability for intraoperative monitoring with total intravenous anesthesia. All patients underwent noncranial surgery. Using a standard technique, VEPs were recorded preoperatively in the awake patients and after induction of anesthesia during surgery. A total of 1436 intraoperative traces were recorded and analyzed. A minor prolongation of the P100 latency of 8% and a more pronounced attenuation of the P100-N145 amplitude of 60% were observed in the anesthetized patients. In most of the anesthetized patients, a stable recording of VEPs was not obtainable. In 4 patients (12.5%), clearly identifiable VEP peaks were detected in more than 90% of the traces recorded intraoperatively. In 88% of the patients, reproducible VEPs were obtained in less than 75% of the intraoperative traces only. We concluded that with standard recording techniques and total intravenous anesthesia, intraoperative VEP monitoring in surgically anesthetized patients is not reliable.

  12. [A significant increase in intraoperative flash visual evoked potential amplitude during craniopharyngioma surgery-case report].

    Science.gov (United States)

    Kawaguchi, Tomohiro; Ogawa, Yoshikazu; Fujiwara, Satoru; Tominaga, Teiji

    2015-04-01

    The flash visual evoked potential (VEP) is a useful diagnostic modality for visual preservation during surgery. Decreased VEP amplitude is recognized to indicate visual deterioration;however, whether intraoperative VEP can detect visual improvement remains unclear. We describe a craniopharyngioma case with a significant increase in VEP amplitude during surgery. A 67-year-old woman presented with progressive gait disturbance and impaired consciousness. Head magnetic resonance imaging demonstrated a sellar-suprasellar tumor compressing the optic chiasm upward with significant ventricular dilation. Her Glasgow Coma Scale was E3V3M5. Visual fields and acuity could not be examined because of impaired consciousness, and she could not see/recognize objects on a table. Preoperative VEP showed reproducible waveforms. Tumor removal by the extended transsphenoidal approach was performed with VEP monitoring. Increased VEP amplitude was observed after dural incision and persisted until the surgery ended. Postoperative VEP waveforms were also reproducible, but visual fields/acuity could not be examined because of cognitive dysfunction. Useful visual function was restored, and she became independent in daily life. The histological diagnosis was craniopharyngioma. The patient underwent ventriculo-peritoneal shunting for hydrocephalus 16 days after tumor removal. The postoperative course was uneventful and she was transferred to another hospital for rehabilitation. Intraoperative VEP may indicate visual improvement during surgery, which is a useful objective assessment for visual function in patients with impaired consciousness and cognitive dysfunction.

  13. Longitudinal Evaluation of Residual Cortical and Subcortical Motor Evoked Potentials in Spinal Cord Injured Rats.

    Science.gov (United States)

    Redondo-Castro, Elena; Navarro, Xavier; García-Alías, Guillermo

    2016-05-15

    We have applied transcranial electrical stimulation to rats with spinal cord injury and selectively tested the motor evoked potentials (MEPs) conveyed by descending motor pathways with cortical and subcortical origin. MEPs were elicited by electrical stimulation to the brain and recorded on the tibialis anterior muscles. Stimulation parameters were characterized and changes in MEP responses tested in uninjured rats, in rats with mild or moderate contusion, and in animals with complete transection of the spinal cord. All injuries were located at the T8 vertebral level. Two peaks, termed N1 and N2, were obtained when changing from single pulse stimulation to trains of 9 pulses at 9 Hz. Selective injuries to the brain or spinal cord funiculi evidenced the subcortical origin of N1 and the cortical origin of N2. Animals with mild contusion showed small behavioral deficits and abolished N1 but maintained small amplitude N2 MEPs. Substantial motor deficits developed in rats with moderate contusion, and these rats had completely eliminated N1 and N2 MEPs. Animals with complete cord transection had abolished N1 and N2 and showed severe impairment of locomotion. The results indicate the reliability of MEP testing to longitudinally evaluate over time the degree of impairment of cortical and subcortical spinal pathways after spinal cord injuries of different severity. PMID:26560177

  14. [A significant increase in intraoperative flash visual evoked potential amplitude during craniopharyngioma surgery-case report].

    Science.gov (United States)

    Kawaguchi, Tomohiro; Ogawa, Yoshikazu; Fujiwara, Satoru; Tominaga, Teiji

    2015-04-01

    The flash visual evoked potential (VEP) is a useful diagnostic modality for visual preservation during surgery. Decreased VEP amplitude is recognized to indicate visual deterioration;however, whether intraoperative VEP can detect visual improvement remains unclear. We describe a craniopharyngioma case with a significant increase in VEP amplitude during surgery. A 67-year-old woman presented with progressive gait disturbance and impaired consciousness. Head magnetic resonance imaging demonstrated a sellar-suprasellar tumor compressing the optic chiasm upward with significant ventricular dilation. Her Glasgow Coma Scale was E3V3M5. Visual fields and acuity could not be examined because of impaired consciousness, and she could not see/recognize objects on a table. Preoperative VEP showed reproducible waveforms. Tumor removal by the extended transsphenoidal approach was performed with VEP monitoring. Increased VEP amplitude was observed after dural incision and persisted until the surgery ended. Postoperative VEP waveforms were also reproducible, but visual fields/acuity could not be examined because of cognitive dysfunction. Useful visual function was restored, and she became independent in daily life. The histological diagnosis was craniopharyngioma. The patient underwent ventriculo-peritoneal shunting for hydrocephalus 16 days after tumor removal. The postoperative course was uneventful and she was transferred to another hospital for rehabilitation. Intraoperative VEP may indicate visual improvement during surgery, which is a useful objective assessment for visual function in patients with impaired consciousness and cognitive dysfunction. PMID:25838303

  15. Development and evaluation of the piecewise Prony method for evoked potential analysis.

    Science.gov (United States)

    Garoosi, V; Jansen, B H

    2000-12-01

    A new method is presented to decompose nonstationary signals into a summation of oscillatory components with time varying frequency, amplitude, and phase characteristics. This method, referred to as piecewise Prony method (PPM), is an improvement over the classical Prony method, which can only deal with signals containing components with fixed frequency, amplitude and phase, and monotonically increasing or decreasing rate of change. PPM allows the study of the temporal profile of post-stimulus signal changes in single-trial evoked potentials (EPs), which can lead to new insights in EP generation. We have evaluated this method on simulated data to test its limitations and capabilities, and also on single-trial EPs. The simulation experiments showed that the PPM can detect amplitude changes as small as 10%, rate changes as small as 10%, and 0.15 Hz of frequency changes. The capabilities of the PPM were demonstrated using single electroencephalogram/EP trials of flash visual EPs recorded from one normal subject. The trial-by-trial results confirmed that the stimulation drastically attenuates the alpha activity shortly after stimulus presentation, with the alpha activity returning about 0.5 s later. The PPM results also provided evidence that delta activity undergoes phase alignment following stimulus presentation.

  16. Learned control over spinal nociception reduces supraspinal nociception as quantified by late somatosensory evoked potentials.

    Science.gov (United States)

    Ruscheweyh, Ruth; Bäumler, Maximilian; Feller, Moritz; Krafft, Stefanie; Sommer, Jens; Straube, Andreas

    2015-12-01

    We have recently shown that subjects can learn to use cognitive-emotional strategies to suppress their spinal nociceptive flexor reflex (RIII reflex) under visual RIII feedback and proposed that this reflects learned activation of descending pain inhibition. Here, we investigated whether learned RIII suppression also affects supraspinal nociception and whether previous relaxation training increases success. Subjects were trained over 3 sessions to reduce their RIII size by self-selected cognitive-emotional strategies. Two groups received true RIII feedback (with or without previous relaxation training) and a sham group received false feedback (15 subjects per group). RIII reflexes, late somatosensory evoked potentials (SEPs), and F-waves were recorded and pain intensity ratings collected. Both true feedback groups achieved significant (P SEP amplitude was significantly reduced during feedback training. Pain intensity was significantly reduced in all 3 groups and also correlated with RIII reduction (r = 0.44, P SEPs, although effects on pain ratings were less clear. Lower motor neuron excitability as quantified by F-waves was not affected. Previous relaxation training did not significantly improve RIII feedback training success. PMID:26270584

  17. The effect of water immersion on short-latency somatosensory evoked potentials in human

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    Sato Daisuke

    2012-01-01

    Full Text Available Abstract Background Water immersion therapy is used to treat a variety of cardiovascular, respiratory, and orthopedic conditions. It can also benefit some neurological patients, although little is known about the effects of water immersion on neural activity, including somatosensory processing. To this end, we examined the effect of water immersion on short-latency somatosensory evoked potentials (SEPs elicited by median nerve stimuli. Short-latency SEP recordings were obtained for ten healthy male volunteers at rest in or out of water at 30°C. Recordings were obtained from nine scalp electrodes according to the 10-20 system. The right median nerve at the wrist was electrically stimulated with the stimulus duration of 0.2 ms at 3 Hz. The intensity of the stimulus was fixed at approximately three times the sensory threshold. Results Water immersion significantly reduced the amplitudes of the short-latency SEP components P25 and P45 measured from electrodes over the parietal region and the P45 measured by central region. Conclusions Water immersion reduced short-latency SEP components known to originate in several cortical areas. Attenuation of short-latency SEPs suggests that water immersion influences the cortical processing of somatosensory inputs. Modulation of cortical processing may contribute to the beneficial effects of aquatic therapy. Trial Registration UMIN-CTR (UMIN000006492

  18. STUDY ON THE SOMESTHETIC EVOKED POTENTIAL IN ELECTRO-ACUPUNCTURE TREATMENT OF CERVICAL SPONDYLOPATHY

    Institute of Scientific and Technical Information of China (English)

    袁青; 张洪来; 靳瑞

    2000-01-01

    In order to study the significance of somesthetic evoked potentials (SEP) in diagnosis of cervical spondylopathy (CS) and judgement of its therapeutic effect, a total of 60 cases of CS patients were randomly divided into electro-acupuncture (EA) group (n=30) and control (traction) group (n=30). Amplitudes of N9, N11, N13, N20 and intervals of N9-N13, N13-N20 andN9-N20 of SEP were used as indexes. After 3 courses of treatment, the clinical therapeutic effect of EA group was significantly superior to that of control group (P<0.01); the amplitudes of the aforementioned components of SEP in both groups increased apparently while the inter-peak latency shortened in different degrees. In EA group, the increased values of various components of SEP amplitude, except for N9, were all larger than those of control group (P<0.05 for N11, P<0.01 for N13 and N20); the values of shortened latency of different components, except for N13-N20, were all larger than those of control group (P<0.01 for N9-N13 and N9-N20). It suggests that SEP possess a certain significance in diagnosis and evaluation of CS and can be used as one of the objective indexes for evaluation of the therapeutic effect.

  19. A Comparative Evaluation of Humphrey Perimetry and the Multi-channel Pattern Visual Evoked Potentials

    Institute of Scientific and Technical Information of China (English)

    Caiping Hu; Lezheng Wu; De-Zheng Wu; Shixian Long

    2000-01-01

    Purposes: To compare the multi-channel pattern visual evoked potentials to Humphrey perimetry in the assessment of central visual function in primary open angle glaucoma.Methods: The multi-channel checkerboard reversal PVEPs waves to full-field and half-field stimulus of 25 normal persons and 74 patients with primary open angle glaucoma were recorded and analyzed, All patients were examined using Humphrey Field Analyzer. The area of visual field corresponding to the area of retina stimulated during multi-channel PVEPs testing were analysed, straight-line correlation and regression analyses of the various multi-channel PVEPs parameters and the total dB losses were performed.Results: The multi-channel PVEPs demonstrated a low detection rate compared with Humprey perimetry in the early glaucoma, absolute latency and field loss were correlated in the late stage of glaucoma, and absolute amplitude and field loss were not correlated.Conclusions: In relation to signalling “early” loss the multi-channel PVEPs was inferior to Humphrey perimetry, in late loss of primary open angle glaucoma, multi-channel PVEPs can provide a valuable, objective complement to Humphrey perimetry.

  20. Attachment style moderates partner presence effects on pain: a laser-evoked potentials study

    Science.gov (United States)

    Paloyelis, Yannis; Condon, Heather; Jenkinson, Paul M.; Williams, Steven C. R.; Fotopoulou, Aikaterini

    2015-01-01

    Social support is crucial for psychological and physical well-being. Yet, in experimental and clinical pain research, the presence of others has been found to both attenuate and intensify pain. To investigate the factors underlying these mixed effects, we administered noxious laser stimuli to 39 healthy women while their romantic partner was present or absent, and measured pain ratings and laser-evoked potentials (LEPs) to assess the effects of partner presence on subjective pain experience and underlying neural processes. Further, we examined whether individual differences in adult attachment style (AAS), alone or in interaction with the partner’s level of attentional focus (manipulated to be either on or away from the participant) might modulate these effects. We found that the effects of partner presence vs absence on pain-related measures depended on AAS but not partner attentional focus. The higher participants’ attachment avoidance, the higher pain ratings and N2 and P2 local peak amplitudes were in the presence compared with the absence of the romantic partner. As LEPs are thought to reflect activity relating to the salience of events, our data suggest that partner presence may influence the perceived salience of events threatening the body, particularly in individuals who tend to mistrust others. PMID:25556212

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

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    Morufu Olusola Ibitoye

    2014-07-01

    Full Text Available 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.

  2. A Comparison of Visual Evoked Potential (VEP)-Based Methods for the Low-Cost Emotiv EPOC Neuroheadset

    OpenAIRE

    Hvaring, Fredrik Tron; Ulltveit-Moe, Andreas H

    2014-01-01

    Brain computer interfaces (BCIs) enable interaction with computers through electrical brain signals recorded from the scalp through an electroencephalogram (EEG). These BCIs are characterized by expensive equipment and long setup times, which limits their commercial use. In this thesis, a BCI was implemented that uses the low-cost EEG acquisition device Emotiv EPOC and visual evoked potentials (VEPs), which are potentials in the EEG elicited by visual stimulus. A structured literature review ...

  3. Rapid and Objective Assessment of Neural Function in Autism Spectrum Disorder Using Transient Visual Evoked Potentials

    Science.gov (United States)

    Siper, Paige M.; Zemon, Vance; Gordon, James; George-Jones, Julia; Lurie, Stacey; Zweifach, Jessica; Tavassoli, Teresa; Wang, A. Ting; Jamison, Jesslyn; Buxbaum, Joseph D.; Kolevzon, Alexander

    2016-01-01

    Objective There is a critical need to identify biomarkers and objective outcome measures that can be used to understand underlying neural mechanisms in autism spectrum disorder (ASD). Visual evoked potentials (VEPs) offer a noninvasive technique to evaluate the functional integrity of neural mechanisms, specifically visual pathways, while probing for disease pathophysiology. Methods Transient VEPs (tVEPs) were obtained from 96 unmedicated children, including 37 children with ASD, 36 typically developing (TD) children, and 23 unaffected siblings (SIBS). A conventional contrast-reversing checkerboard condition was compared to a novel short-duration condition, which was developed to enable objective data collection from severely affected populations who are often excluded from electroencephalographic (EEG) studies. Results Children with ASD showed significantly smaller amplitudes compared to TD children at two of the earliest critical VEP components, P60-N75 and N75-P100. SIBS showed intermediate responses relative to ASD and TD groups. There were no group differences in response latency. Frequency band analyses indicated significantly weaker responses for the ASD group in bands encompassing gamma-wave activity. Ninety-two percent of children with ASD were able to complete the short-duration condition compared to 68% for the standard condition. Conclusions The current study establishes the utility of a short-duration tVEP test for use in children at varying levels of functioning and describes neural abnormalities in children with idiopathic ASD. Implications for excitatory/inhibitory balance as well as the potential application of VEP for use in clinical trials are discussed. PMID:27716799

  4. Effects of flurbiprofen enantiomers on pain-related chemo-somatosensory evoked potentials in human subjects.

    Science.gov (United States)

    Lötsch, J; Geisslinger, G; Mohammadian, P; Brune, K; Kobal, G

    1995-01-01

    1. The aim of the study was to investigate the analgesic effects of flurbiprofen enantiomers using an experimental pain model based on both chemo-somatosensory event-related potentials (CSSERP) and subjective pain ratings. 2. Healthy female volunteers (n = 16, age 23-36 years) participated in a placebo-controlled, randomised, double-blind, four-way crossover study. Single doses of (S)-flurbiprofen (50 mg), (R)-flurbiprofen (50 and 100 mg) and placebo were administered orally. Measurements were taken before and 2 h after administration of the medications. During each measurement, 32 painful stimuli of gaseous carbon dioxide (200 ms duration, interval approximately 30 s) of two concentrations (60 and 65% CO2 v/v) were applied to the right nostril. EEG was recorded from five positions and CSSERP were obtained in response to the painful CO2- stimuli. Additionally, subjects rated the perceived intensity of the painful stimuli by means of a visual analogue scale (VAS). 3. The CSSERP-amplitude P2, a measure of analgesic effect, decreased after administration of both (R)- and (S)-flurbiprofen, while it increased after placebo. This was statistically significant at recording positions C4 (P < 0.01) and Fz (P < 0.05). The analgesia-related decreases in evoked potential produced by (R)-flurbiprofen were dose-dependent. Comparing similar doses of (R)- and (S)-flurbiprofen, the decrease in CSSERP-amplitudes produced by the (S)-enantiomer was somewhat more pronounced, indicating a higher analgesic potency. 4. The present data indicate that both enantiomers of flurbiprofen produce analgesic effects. Since (R)-flurbiprofen caused only little toxicity in rats as compared with the (S)-enantiomer or the racemic compound, a reduction of the quantitatively most important side effects in the gastrointestinal tract might be achieved by employing (R)-flurbiprofen in pain therapy. PMID:8554936

  5. Effect of renewed SS-cream on spinal somatosensory evoked potential in rabbits

    Institute of Scientific and Technical Information of China (English)

    LongTian; Zhong-ChengXin; HuaXin; JieFu; Yi-MingYuan; Wu-JiangLiu; ChunYang

    2004-01-01

    Aim:The effect of a renewed SS-cream (RSSC) on the treatment of premature ejaculation (PE) was evaluated and compared with the original SS-cream (OSSC).Methods: Sixty male white New Zealand rabbits,weighing 2.5kg-3.0kg,were divided at random into 3 groups:the RSSC,OSSC and placebo groups.The spinal somatosensory evoked potential (SSEP) elicited by electric stimulation of the glans penis with disk electrode was investigated with an electrophysiograph (Poseidomn,Shanghai,China) before and 10,30 and 60 min after drug or placebo application on the glans.The Onset and the N1 latencies and the amplitude of SSEP were recorded and analyzed. Results:There was no significant difference (P>0.05) in the mean Onset and N1 latency of SSEP among the 3 groups before drug application.Compared with the pre-application value,the mean Onset and N 1 latencies in the RSSC and OSSC groups were significantly prolonged at 10,30 and 60 min after treatment (P0.05) in the placebo group.The mean Onset latency of RSSC at 10 and 30 min and that of OSSC at 30 min were significantly delayed (P<0.05) compared with the placebo group.The mean N1 latency of RSSC at 30 and 60 min and that of OSSC group at 30 min were also significantly delayed (P<0.05).Conclusion:RSSC delays the latencies of SSEP,suggesting a local desensitizing effect on the sensory receptor of the glans penis dorsal nerve,which provides the potential for PE treatment.The desensitizing effect of RSSC is higher than that of OSSC.( Asian J Androl 2004 Mar;6:15-18)

  6. expression, physiological actions and therapeutic potential

    OpenAIRE

    Steckelings, Ulrike

    2012-01-01

    Angiotensin II mediates its action via 2 receptor subtypes: the AT1- and AT2-receptor. The existence of more than one receptor for angiotensin II has been discovered not earlier than 1989. This "Habilitationsschrift" is based on six publications which represent mosaic stones within the growing picture of AT2-receptor expression, regulation of expression, physiological and patho-physiological function as well as potential therapeutic use. The first part is dealing with tissue specific ex...

  7. Auditory evoked potentials in young patients with Down syndrome. Event-related potentials (P3) and histaminergic system.

    Science.gov (United States)

    Seidl, R; Hauser, E; Bernert, G; Marx, M; Freilinger, M; Lubec, G

    1997-06-01

    Subjects with Down syndrome exhibit various types of cognitive impairment. Besides abnormalities in a number of neurotransmitter systems (e.g. cholinergic), histaminergic deficits have recently been identified. Brainstem auditory evoked potentials (BAEPs) and auditory event-related potentials (ERPs), were recorded from 10 children (aged 11-20 years) with Down syndrome and from 10 age- and sex-matched healthy control subjects. In Down subjects, BAEPs revealed shortened latencies for peaks III and V with shortened interpeak latencies I-III and I-V. ERPs showed a delay of components N1, P2, N2 and P3. In addition, subjects with Down syndrome failed to show P3 amplitude reduction during repeated stimulation. To evaluate the cognitive effects of histaminergic dysfunction, ERPs were recorded from 12 healthy adults (aged 20-28 years) before and after antihistaminergic intervention (pheniramine) compared to placebo. Whereas components N1, P2, N2 remained unchanged after H1-receptor antagonism, P3 latency increased and P3 amplitude showed no habituation in response to repeated stimulation. The results suggest that the characteristic neurofunctional abnormalities present in children with Down syndrome must be the consequence of a combination of structural and neurochemical aberrations. The second finding was that antihistaminergic treatment affects information processing tested by ERPs similar to that seen with anticholinergic treatment.

  8. Prognostic value of somatosensory-evoked potentials in neurology: A critical review in hypoxic encephalopathy.

    Science.gov (United States)

    Song, Yanhai; Prakash, Ravi; Reddy, Jayashankar

    2016-01-01

    Prediction of prognosis in comatose patients surviving a cardiac arrest is still one of the intractable problems in critical care neurology because of lack of fool-proof ways to assess the outcome. Of all these measures, somatosensory-evoked potential (SSEP) has been perhaps the most evaluated and heavily relied-upon tool over the past several decades for assessing coma. Recent studies have given rise to concerns regarding the "absoluteness" of SSEP signals for the prognostic evaluation of coma. In this critical review, we searched the literature to focus on studies conducted so far on the prognostic evaluation of postanoxic coma using SSEPs. All those studies published on the use of SSEP as a prognostication tool in postanoxic coma were reviewed. A narrative review was created that included the strengths as well as limitations of the use of SSEP in postanoxic coma. The use of SSEP in coma has been universal for the purpose of prognostication. However, it has its own advantages as well as limitations. The limitations include challenges in performing and getting SSEP signals during coma as well as the challenges involved in reading and interpreting the signals. The recent usage of therapeutic hypothermia has become another factor that often interferes with the SSEP recording. Finally, based on these study results, some recommendations are generated for the effective use of SSEPs in comatose patients for further prognostication. We advocate that SSEP should be an integral component for the assessment of postanoxic comatose patients due to its several advantages over other assessment tools. However, SSEP recordings should follow certain standards. One should be aware that its interpretation may be biased by several factors. The bias created by the concept of "self-fulfilling hypothesis" should always be borne in mind before discontinuation of life support systems in terminal patients. PMID:27147145

  9. Steady state visually evoked potentials based Brain computer interface test outside the lab

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    Eduardo Francisco Caicedo Bravo

    2016-06-01

    Full Text Available Context: Steady State Visually Evoked Potentials (SSVEP are brain signals which are one of the most promising signals for Brain Computer Interfaces (BCIs implementation, however, SSVEP based BCI generally are proven in a controlled environment and there are a few tests in demanding conditions.Method: We present a SSVEP based BCI system that was used outside the lab in a noisy environment with distractions, and with the presence of public. For the tests, we showed a maze in a laptop where the user could move an avatar looking for a target that is represented by a house.  In order to move the avatar, the volunteer must stare at one of the four visual stimuli; the four visual stimuli represent the four directions: right, up, left, and down. The system is proven without any calibration procedure.Results: 32 volunteers utilized the system and 20 achieved the target with an accuracy above 60%, including 9 with an accuracy of 100%, 7 achieved the target with an accuracy below 60% and 5 left without achieving the goal. For the volunteers who reached accuracy above 60%, the results of the performance achieved an average of 6,4s for command detections, precision of 79% and information transfer rate (ITR of 8,78 bits/s.Conclusions: We showed a SSVEP based BCI system with low cost, it was proved in a public event, it did not have calibration procedures, it was easy to install, and it was used for people in a wide age range. The results show that it is possible to bring this kind of systems to environments outside the laboratory.

  10. Non-dominant hand movement facilitates the frontal N30 somatosensory evoked potential

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    Legon Wynn

    2010-09-01

    Full Text Available Abstract Background Previous literature has shown that the frontal N30 is increased during movement of the hand contralateral to median nerve stimulation. This finding was a result of non-dominant left hand movement in right-handed participants. It is unclear however if the effect depends upon non-dominant hand movement or if this is a generalized phenomenon across the upper-limbs. This study tests the effect of dominant and non-dominant hand movement upon contralateral frontal and parietal somatosensory evoked potentials (SEPs and further tests if this relationship persists in left hand dominant participants. Median nerve SEPs were elicited from the wrist contralateral to movement in both right hand and left hand dominant participants alternating the movement hand in separate blocks. Participants were required to volitionally squeeze (~ 20% of a maximal voluntary contraction a pressure-sensitive bulb every ~3 seconds with the hand contralateral to median nerve stimulation. SEPs were continuously collected during the task and individual traces were grouped into time bins relative to movement according to the timing of components of the Bereitschaftspotential. SEPs were then averaged and quantified from both FCZ and CP3/4 scalp electrode sites during both the squeeze task and at rest. Results The N30 is facilitated during non-dominant hand movement in both right and left hand dominant individuals. There was no effect for dominant hand movement in either group. Conclusions N30 amplitude increase may be a result of altered sensory gating from motor areas known to be specifically active during non-dominant hand movement.

  11. Prandial states modify the reactivity of the gustatory cortex using gustatory evoked potentials in humans

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    Agnès eJACQUIN-PIQUES

    2016-01-01

    Full Text Available Previous functional Magnetic Resonance Imaging studies evaluated the role of satiety on cortical taste area activity and highlighted decreased activation in the orbito-frontal cortex when food was eaten until satiation. The modulation of orbito-frontal neurons (secondary taste area by ad libitum food intake has been associated with the pleasantness of the food’s flavor. The insula and frontal operculum (primary taste area are also involved in reward processing. The aim was to compare human gustatory evoked potentials (GEP recorded in the primary and secondary gustatory cortices in a fasted state with those after food intake. Fifteen healthy volunteers were enrolled in this observational study. In each of two sessions, two GEP recordings were performed (at 11:00 am and 1:30 pm in response to sucrose gustatory stimulation, and a sucrose-gustatory threshold was determined. During one session, a standard lunch was provided between the two GEP recordings. During the other session, subjects had nothing to eat. Hunger sensation, wanting, liking and the perception of the solution’s intensity were evaluated with visual analogue scales. GEP latencies measured in the Pz (p<0.001, Cz (p<0.01, Fz (p<0.001 recordings (primary taste area were longer after lunch than in the pre-prandial condition. Fp1 and Fp2 latencies (secondary taste area tended to be longer after lunch, but the difference was not significant. No difference was observed for the sucrose-gustatory threshold regardless of the session and time. Modifications in the primary taste area activity during the post-prandial period occurred regardless of the nature of the food eaten and could represent the activity of the frontal operculum and insula, which was recently shown to be modulated by gut signals (GLP-1, CCK, ghrelin, or insulin through vagal afferent neurons or metabolic changes of the internal milieu after nutrient absorption. This trial was registered at clinicalstrials.gov as NCT

  12. Dynamic topography of pattern visual evoked potentials (PVEP) in psychogenic visual loss patients.

    Science.gov (United States)

    Nakamura, A; Tabuchi, A; Matsuda, E; Yamaguchi, W

    2000-09-01

    We investigated to measure the objective visual acuity using pattern visual evoked potentials (PVEP) to help the diagnosis with psychogenic visual loss (PVL) who ranged in age from 7 to 14 years old. Pattern stimuli consisted of black and white checkerboard patterns (39, 26, 15 and 9') with a visual angle of 8 degrees and a contrast level of 15%. The pattern reversal frequency was 0.7 Hz. This resulted in an average of 100 PVEP per session. Visual acuity of 0.1 was consistent with the 39' pattern, 0.2 with the 26' pattern, 0.5 with the 15' pattern, and 1.0 with the 9' pattern. As the results, five PVL patients could measure visual acuity with this method in the present study. The PVEP is useful in evaluating the visual acuity and helped to diagnose the PVL patients. In addition we used the dynamic topography to study the difference in the results of the PVEP. The dynamic topography obtained from the results of the PVEP was analyzed. The flow type of the P100 component diverged into three types (separated type, hollow type and localized type) in the PVL patients and the normal children. The localized type was observed in 59.1% of normal children and in 56.3% of PVL patients. While the separated type was shown in 6.8% of normal children and in 8.3% of PVL patients. There were not significant differences between the PVL patients and the normal children in each type.

  13. Can bispectral index or auditory evoked potential index predict implicit memory during propofol-induced sedation?

    Institute of Scientific and Technical Information of China (English)

    WANG Yun; YUE Yun; SUN Yong-hai; WU An-shi

    2006-01-01

    Background Some patients still suffer from implicit memory of intraoperative events under adequate depth of anaesthesia. The elimination of implicit memory should be a necessary aim of clinical general anaesthesia.However, implicit memory cannot be tested during anaesthesia yet. We propose bispectral index (BIS) and auditory evoked potential index (AEPI), as predictors of implicit memory during anaesthesia.Methods Thirty-six patients were equally divided into 3 groups according to the Observer's Assessment of Alertness/Sedation Score: A, level 3; B, level 2 ;and C, level 1. Every patient was given the first auditory stimulus before sedation. Then every patient received the second auditory stimulus after the target level of sedation had been reached. BIS and AEPI were monitored before and after the second auditory stimulus presentation. Four hours later, the inclusion test and exclusion test were performed on the ward using process dissociation procedure and the scores of implicit memory estimated.Results In groups A and B but not C, implicit memory estimates were statistically greater than zero (P<0.05).The implicit memory scores in group A did not differ significantly from those in group B (P>0.05). Implicit memory scores correlated with BIS and AEPI (P<0.01). The area under ROC curve is BIS> AEPI. The 95% cutoff points of BIS and AEPI for predicting implicit memory are 47 and 28, respectively.Conclusions Implicit memory does not disappear until the depth of sedation increases to level 1 of OAA/S score. Implicit memory scores correlate well with BIS and AEPI during sedation. BIS is a better index for predicting implicit memory than AEPI during propofol induced sedation.

  14. Fractal Dimension Analysis of Transient Visual Evoked Potentials: Optimisation and Applications

    Science.gov (United States)

    Boon, Mei Ying; Henry, Bruce Ian; Chu, Byoung Sun; Basahi, Nour; Suttle, Catherine May; Luu, Chi; Leung, Harry; Hing, Stephen

    2016-01-01

    Purpose The visual evoked potential (VEP) provides a time series signal response to an external visual stimulus at the location of the visual cortex. The major VEP signal components, peak latency and amplitude, may be affected by disease processes. Additionally, the VEP contains fine detailed and non-periodic structure, of presently unclear relevance to normal function, which may be quantified using the fractal dimension. The purpose of this study is to provide a systematic investigation of the key parameters in the measurement of the fractal dimension of VEPs, to develop an optimal analysis protocol for application. Methods VEP time series were mathematically transformed using delay time, τ, and embedding dimension, m, parameters. The fractal dimension of the transformed data was obtained from a scaling analysis based on straight line fits to the numbers of pairs of points with separation less than r versus log(r) in the transformed space. Optimal τ, m, and scaling analysis were obtained by comparing the consistency of results using different sampling frequencies. The optimised method was then piloted on samples of normal and abnormal VEPs. Results Consistent fractal dimension estimates were obtained using τ = 4 ms, designating the fractal dimension = D2 of the time series based on embedding dimension m = 7 (for 3606 Hz and 5000 Hz), m = 6 (for 1803 Hz) and m = 5 (for 1000Hz), and estimating D2 for each embedding dimension as the steepest slope of the linear scaling region in the plot of log(C(r)) vs log(r) provided the scaling region occurred within the middle third of the plot. Piloting revealed that fractal dimensions were higher from the sampled abnormal than normal achromatic VEPs in adults (p = 0.02). Variances of fractal dimension were higher from the abnormal than normal chromatic VEPs in children (p = 0.01). Conclusions A useful analysis protocol to assess the fractal dimension of transformed VEPs has been developed. PMID:27598422

  15. MRI findings and correlative study of MRI and visual evoked potentials in optic neuritis

    International Nuclear Information System (INIS)

    Objective: To investigate the effective MRI sequences and describe the correlation between MRI and visual evoked potential (VEP) in diagnosing optic neuritis. Methods: One hundred and fifty-four eyes with visual impairment of 98 patients with diagnoses of optic neuritis, papillitis, multiple sclerosis and Devic's disease underwent MRI and VEP examination. The MRI findings were analyzed and correlated with VEP results and clinical presentation by using X2 test, wilco xon test and Kappa test. Results Out of the 154 sick eyes, 56 eyes presented thickened optic nerves, 76 eyes had normal diameter of the optic nerve, and 22 eyes had thin optic nerves. A total of 132 optic nerves showed abnormally high signal in STIR sequences, including involvement of intraocular segment in 7, intraorbital segment in 1.35, intracanalicular segment in 109, intracranial segment in 97, optic chiasm in 56, and optic tract in 23. A total of 54 patients underwent postcontrast MRI. Seventy-four optic nerves of 87 eyes showed enhancement. Among the 196 eyes of 98 patients, 132 eyes presented visual impairment and simultaneous abnormal MR signal of the optic nerve, and 26 eyes had both normal vision and normal MR signal of optic nerve. The consistency of MRI findings and vision status was 80. 61% (Kappa 0.453,P1-weighted MR sequence combined with fat- suppression are helpful in diagnosis of optic neuritis. VEP is helpful in diagnosing optic neuritis and in finding subclinical visual problem. The MRI combined with VEP could improve the diagnostic accuracy of optic neuritis. (authors)

  16. Advancing the detection of steady-state visual evoked potentials in brain-computer interfaces

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    Abu-Alqumsan, Mohammad; Peer, Angelika

    2016-06-01

    Objective. Spatial filtering has proved to be a powerful pre-processing step in detection of steady-state visual evoked potentials and boosted typical detection rates both in offline analysis and online SSVEP-based brain-computer interface applications. State-of-the-art detection methods and the spatial filters used thereby share many common foundations as they all build upon the second order statistics of the acquired Electroencephalographic (EEG) data, that is, its spatial autocovariance and cross-covariance with what is assumed to be a pure SSVEP response. The present study aims at highlighting the similarities and differences between these methods. Approach. We consider the canonical correlation analysis (CCA) method as a basis for the theoretical and empirical (with real EEG data) analysis of the state-of-the-art detection methods and the spatial filters used thereby. We build upon the findings of this analysis and prior research and propose a new detection method (CVARS) that combines the power of the canonical variates and that of the autoregressive spectral analysis in estimating the signal and noise power levels. Main results. We found that the multivariate synchronization index method and the maximum contrast combination method are variations of the CCA method. All three methods were found to provide relatively unreliable detections in low signal-to-noise ratio (SNR) regimes. CVARS and the minimum energy combination methods were found to provide better estimates for different SNR levels. Significance. Our theoretical and empirical results demonstrate that the proposed CVARS method outperforms other state-of-the-art detection methods when used in an unsupervised fashion. Furthermore, when used in a supervised fashion, a linear classifier learned from a short training session is able to estimate the hidden user intention, including the idle state (when the user is not attending to any stimulus), rapidly, accurately and reliably.

  17. Effects of symptomatic treatments on cutaneous hyperalgesia and laser evoked potentials during migraine attack.

    Science.gov (United States)

    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.

  18. Evaluation of brain stem auditory evoked potentials in stable patients with chronic obstructive pulmonary disease

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    Gupta Prem

    2008-01-01

    Full Text Available Though there are few studies addressing brainstem auditory evoked potentials (BAEP in patients with chronic obstructive pulmonary disease (COPD, subclinical BAEP abnormalities in stable COPD patients have not been studied. The present study aimed to evaluate the BAEP abnormalities in this study group. Materials and Methods : In the present study, 80 male subjects were included: COPD group comprised 40 smokers with stable COPD with no clinical neuropathy; 40 age-matched healthy volunteers served as the control group. Latencies of BAEP waves I, II, III, IV, and V, together with interpeak latencies (IPLs of I-III, I-V, and III-V, and amplitudes of waves I-Ia and V-Va were studied in both the groups to compare the BAEP abnormalities in COPD group; the latter were correlated with patient characteristics and Mini-Mental Status Examination Questionnaire (MMSEQ scores to seek any significant correlation. Results: Twenty-six (65% of the 40 COPD patients had BAEP abnormalities. We observed significantly prolonged latencies of waves I, III, V over left ear and waves III, IV, V over right ear; increased IPLs of I-V, III-V over left ear and of I-III, I-V, III-V over right side. Amplitudes of waves I-Ia and V-Va were decreased bilaterally. Over left ear, the latencies of wave I and III were significantly correlated with FEV 1 ; and amplitude of wave I-Ia, with smoking pack years. A weak positive correlation between amplitude of wave I-Ia and duration of illness; and a weak negative correlation between amplitude of wave V-Va and MMSEQ scores were seen over right side. Conclusions : We observed significant subclinical BAEP abnormalities on electrophysiological evaluation in studied stable COPD male patients having mild-to-moderate airflow obstruction.

  19. Nicotinic modulation of auditory evoked potential electroencephalography in a rodent neurodevelopmental model of schizophrenia.

    Science.gov (United States)

    Kohlhaas, Kathy L; Robb, Holly M; Roderwald, Victoria A; Rueter, Lynne E

    2015-10-15

    Schizophrenia is a chronic disease that has been hypothesized to be linked to neurodevelopmental abnormalities. Schizophrenia patients exhibit impairments in basic sensory processing including sensory gating deficits in P50 and mismatch negativity (MMN). Neuronal nicotinic acetylcholine receptor (nAChR) agonists have been reported to attenuate these deficits. Gestational exposure of rats to methylazoxymethanol acetate (MAM) at embryonic day 17 leads to developmental disruption of the limbic-cortical system. MAM exposed offspring show neuropathological and behavioral changes that have similarities with those seen in schizophrenia. In this study, we aimed to assess whether N40 auditory sensory gating (the rodent form of P50 gating) and MMN deficits as measures of auditory evoked potential (AEP) electroencephalography (EEG) are present in MAM rats and whether nAChR agonists could attend the deficit. E17 male MAM and sham rats were implanted with cortical electrodes at 2 months of age. EEG recordings evaluating N40 gating and MMN paradigms were done comparing effects of vehicle (saline), nicotine and the α7 agonist ABT-107. Deficits were seen for MAM rats compared to sham animals in both N40 auditory sensory gating and MMN AEP recordings. There was a strong trend for N40 deficits to be attenuated by both nicotine (0.16mg/kg i.p. base) and ABT-107 (1.0mg/kg i.p. base). MMN deficits were significantly attenuated by ABT-107 but not by nicotine. These data support the MAM model as a useful tool for translating pharmacodynamic effects in clinical medicine studies of novel therapeutic treatments for schizophrenia.

  20. The Changes of Pattern Reversal Visual Evoked Potentials in Normal Infants

    Institute of Scientific and Technical Information of China (English)

    YanFenLiu; JianGe

    1995-01-01

    Purpose:To study pattern reversal visual evoked potential(PVEPs)and deter-mine the developmental character and mature time of visual function in normal in-fants t different months of age.Methods:PVEPs were recorded from115normal infants at3,6,9,12moths age.P1latency for different checks(1°40′,25′,6′)was analyzed and compared to those of normal adults,Changes of N1,N2latency of PVEPs were also exam-ioned.Results:P1 latency for all checks(1°40′,25′,6′)was significantly longer at 3months than at 6months of age(P0.05).P1latency for larger checks(1°40′)reached adult level after 3months of age,but not for the intermediate check(25′),while P1latency for small check(6′)presented the character of fluctuation.Conclusion:The visual system continued to develop after birth and appeared a certain regularity,Our results showed thatP1latency for larger check(1°40′)reached adult levels after 3months of age.ButP1latency for intermediate check still has not reached adult levels after 3months of age.To deterine the age at which adult levels are finally reached,infants of 12months and older must be tested.The reason why P1latency for smaller check(6′)presented the character of fluctuation should be the temporal tuning function developing much more slowly.Eye Science1995;11:161-164.

  1. Usefulness of intraoperative monitoring of visual evoked potentials in transsphenoidal surgery.

    Science.gov (United States)

    Kamio, Yoshinobu; Sakai, Naoto; Sameshima, Tetsuro; Takahashi, Goro; Koizumi, Shinichiro; Sugiyama, Kenji; Namba, Hiroki

    2014-01-01

    Postoperative visual outcome is a major concern in transsphenoidal surgery (TSS). Intraoperative visual evoked potential (VEP) monitoring has been reported to have little usefulness in predicting postoperative visual outcome. To re-evaluate its usefulness, we adapted a high-power light-stimulating device with electroretinography (ERG) to ascertain retinal light stimulation. Intraoperative VEP monitoring was conducted in TSSs in 33 consecutive patients with sellar and parasellar tumors under total venous anesthesia. The detectability rates of N75, P100, and N135 were 94.0%, 85.0%, and 79.0%, respectively. The mean latencies and amplitudes of N75, P100, and N135 were 76.8 ± 6.4 msec and 4.6 ± 1.8 μV, 98.0 ± 8.6 msec and 5.0 ± 3.4 μV, and 122.1 ± 16.3 msec and 5.7 ± 2.8 μV, respectively. The amplitude was defined as the voltage difference from N75 to P100 or P100 to N135. The criterion for amplitude changes was defined as a > 50% increase or 50% decrease in amplitude compared to the control level. The surgeon was immediately alerted when the VEP changed beyond these thresholds, and the surgical manipulations were stopped until the VEP recovered. Among the 28 cases with evaluable VEP recordings, the VEP amplitudes were stable in 23 cases and transiently decreased in 4 cases. In these 4 cases, no postoperative vision deterioration was observed. One patient, whose VEP amplitude decreased without subsequent recovery, developed vision deterioration. Intraoperative VEP monitoring with ERG to ascertain retinal light stimulation by the new stimulus device was reliable and feasible in preserving visual function in patients undergoing TSS.

  2. Clinical utility and limitations of intraoperative monitoring of visual evoked potentials.

    Directory of Open Access Journals (Sweden)

    Yeda Luo

    Full Text Available 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.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.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.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.

  3. Sensory Attenuation Assessed by Sensory Evoked Potentials in Functional Movement Disorders.

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    Antonella Macerollo

    Full Text Available Functional (psychogenic movement disorders (FMD have features associated with voluntary movement (e.g. distractibility but patients report movements to be out of their control. One explanation for this phenomenon is that sense of agency for movement is impaired. The phenomenon of reduction in the intensity of sensory experience when movement is self-generated and a reduction in sensory evoked potentials (SEPs amplitude at the onset of self-paced movement (sensory attenuation have been linked to sense of agency for movement.We compared amplitude of SEPs from median nerve stimulation at rest and at the onset of a self-paced movement of the thumb in 17 patients with FMD and 17 healthy controls.Patients showed lack of attenuation of SEPs at the onset of movement compared to reduction in amplitude of SEPs in controls. FMD patients had significantly different ratios of movement onset to rest SEPs than did healthy controls at each electrode: 0.79 in healthy controls and 1.35 in patients at F3 (t = -4.22, p<0.001, 0.78 in healthy controls and 1.12 at patients C3 (t = -3.15, p = 0.004 and 0.77 in healthy controls and 1.05 at patients P3 (t = -2.88, p = 0.007.Patients with FMD have reduced sensory attenuation as measured by SEPs at onset of self-paced movement. This finding can be plausibly linked to impairment of sense of agency for movement in these patients.

  4. Somatosensory evoked potentials assess the efficacy of circumcision for premature ejaculation.

    Science.gov (United States)

    Xia, J-D; Jiang, H-S; Zhu, L-L; Zhang, Z; Chen, H; Dai, Y-T

    2016-07-01

    To assess the efficacy and mechanism of circumcision in the treatment of premature ejaculation (PE) with redundant prepuce, we enrolled a total of 81 PE patients who received circumcision. The patients' ejaculatory ability and sexual performances were evaluated before and after circumcision by using questionnaires (Intravaginal ejaculation latency time (IELT), Chinese Index of PE with 5 questions (CIPE-5) and International Index of Erectile function- 5 (IIEF-5)). Furthermore, somatosensory evoked potentials (SEPs) including dorsal nerve (DNSEP) and glans penis (GPSEP) of the patients were also measured. The mean IELTs of preoperation and post operation were 1.10±0.55 and 2.48±2.03 min, respectively (P<0.001). In addition, the geometric mean IELT after operation was 2.16 min, compared with the baseline 1.07 min before the operation, the fold increase of the IELT was 2.02. Compared with the uncircumcised status, scores of CIPE-5 showed a significant increase after circumcision (P<0.001). The mean latencies (and amplitudes) of GPSEP and DNSEP were 38.1±4.0 ms (3.0±1.9 uV) and 40.5±3.4 ms (2.8±1.6 uV) before circumcision, respectively; and 42.8±3.3 ms (2.8±1.6 uV) and 40.5±4.1 ms (2.4±1.2 uV) in the follow-up end point after circumcision. Only the latencies of GPSEP showed significant prolongation before and after circumcision (P<0.001). The ejaculation time improvement after circumcision is so small, and equal to placebo response, therefore it could not be interpreted as a therapeutic method in men with PE. PMID:27193064

  5. Single-Trial Extraction of Pure Somatosensory Evoked Potential Based on Expectation Maximization Approach.

    Science.gov (United States)

    Chen, Wei; Chang, Chunqi; Hu, Yong

    2016-01-01

    It is of great importance for intraoperative monitoring to accurately extract somatosensory evoked potentials (SEPs) and track its changes fast. Currently, multi-trial averaging is widely adopted for SEP signal extraction. However, because of the loss of variations related to SEP features across different trials, the estimated SEPs in such a way are not suitable for the purpose of real-time monitoring of every single trial of SEP. In order to handle this issue, a number of single-trial SEP extraction approaches have been developed in the literature, such as ARX and SOBI, but most of them have their performance limited due to not sufficient utilization of multi-trial and multi-condition structures of the signals. In this paper, a novel Bayesian model of SEP signals is proposed to make systemic use of multi-trial and multi-condition priors and other structural information in the signal by integrating both a cortical source propagation model and a SEP basis components model, and an Expectation Maximization (EM) algorithm is developed for single-trial SEP estimation under this model. Numerical simulations demonstrate that the developed method can provide reasonably good single-trial estimations of SEP as long as signal-to-noise ratio (SNR) of the measurements is no worse than -25 dB. The effectiveness of the proposed method is further verified by its application to real SEP measurements of a number of different subjects during spinal surgeries. It is observed that using the proposed approach the main SEP features (i.e., latencies) can be reliably estimated at single-trial basis, and thus the variation of latencies in different trials can be traced, which provides a solid support for surgical intraoperative monitoring. PMID:26742104

  6. Methylphenidate alters flash-evoked potentials, body temperature, and behavior in Long-Evans rats.

    Science.gov (United States)

    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.

  7. Long-latency TMS-evoked potentials during motor execution and inhibition

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    Kentaro eYamanaka

    2013-11-01

    Full Text Available Transcranial magnetic stimulation (TMS has often been used in conjunction with electroencephalography (EEG, which is effective for the direct demonstration of cortical reactivity and corticocortical connectivity during cognitive tasks through the spatio-temporal pattern of long-latency TMS-evoked potentials (TEPs. However, it remains unclear what pattern is associated with the inhibition of a planned motor response. Therefore, we performed TMS-EEG recording during a go/stop task, in which participants were instructed to click a computer mouse with a right index finger when an indicator that was moving with a constant velocity reached a target (go trial or to avoid the click when the indicator randomly stopped just before it reached the target (stop trial. Single-pulse TMS to the left (contralateral or right (ipsilateral motor cortex was applied 500 ms before or just at the target time. TEPs related to motor execution and inhibition were obtained by subtractions between averaged EEG waveforms with and without TMS. As a result, in TEPs induced by both contralateral and ipsilateral TMS, small oscillations were followed by a prominent negative deflection around the TMS site peaking at approximately 100 ms post-TMS (N100, and a less pronounced later positive component (LPC over the broad areas that was centered at the midline-central site in both go and stop trials. However, compared to the pattern in go and stop trials with TMS at 500 ms before the target time, N100 and LPC were differently modulated in the go and stop trials with TMS just at the target time. The amplitudes of both N100 and LPC decreased in go trials, while the amplitude of LPC decreased and the latency of LPC was delayed in both go and stop trials. These results suggested that TMS-induced neuronal reactions in the motor cortex and subsequent their propagation to surrounding cortical areas might change functionally according to task demand when executing and inhibiting a motor

  8. Long-latency TMS-evoked potentials during motor execution and inhibition.

    Science.gov (United States)

    Yamanaka, Kentaro; Kadota, Hiroshi; Nozaki, Daichi

    2013-01-01

    Transcranial magnetic stimulation (TMS) has often been used in conjunction with electroencephalography (EEG), which is effective for the direct demonstration of cortical reactivity and corticocortical connectivity during cognitive tasks through the spatio-temporal pattern of long-latency TMS-evoked potentials (TEPs). However, it remains unclear what pattern is associated with the inhibition of a planned motor response. Therefore, we performed TMS-EEG recording during a go/stop task, in which participants were instructed to click a computer mouse with a right index finger when an indicator that was moving with a constant velocity reached a target (go trial) or to avoid the click when the indicator randomly stopped just before it reached the target (stop trial). Single-pulse TMS to the left (contralateral) or right (ipsilateral) motor cortex was applied 500 ms before or just at the target time. TEPs related to motor execution and inhibition were obtained by subtractions between averaged EEG waveforms with and without TMS. As a result, in TEPs induced by both contralateral and ipsilateral TMS, small oscillations were followed by a prominent negative deflection around the TMS site peaking at approximately 100 ms post-TMS (N100), and a less pronounced later positive component (LPC) over the broad areas that was centered at the midline-central site in both go and stop trials. However, compared to the pattern in go and stop trials with TMS at 500 ms before the target time, N100 and LPC were differently modulated in the go and stop trials with TMS just at the target time. The amplitudes of both N100 and LPC decreased in go trials, while the amplitude of LPC decreased and the latency of LPC was delayed in both go and stop trials. These results suggested that TMS-induced neuronal reactions in the motor cortex and subsequent their propagation to surrounding cortical areas might change functionally according to task demand when executing and inhibiting a motor response.

  9. Somatosensory evoked potentials assess the efficacy of circumcision for premature ejaculation.

    Science.gov (United States)

    Xia, J-D; Jiang, H-S; Zhu, L-L; Zhang, Z; Chen, H; Dai, Y-T

    2016-07-01

    To assess the efficacy and mechanism of circumcision in the treatment of premature ejaculation (PE) with redundant prepuce, we enrolled a total of 81 PE patients who received circumcision. The patients' ejaculatory ability and sexual performances were evaluated before and after circumcision by using questionnaires (Intravaginal ejaculation latency time (IELT), Chinese Index of PE with 5 questions (CIPE-5) and International Index of Erectile function- 5 (IIEF-5)). Furthermore, somatosensory evoked potentials (SEPs) including dorsal nerve (DNSEP) and glans penis (GPSEP) of the patients were also measured. The mean IELTs of preoperation and post operation were 1.10±0.55 and 2.48±2.03 min, respectively (PIELT after operation was 2.16 min, compared with the baseline 1.07 min before the operation, the fold increase of the IELT was 2.02. Compared with the uncircumcised status, scores of CIPE-5 showed a significant increase after circumcision (P<0.001). The mean latencies (and amplitudes) of GPSEP and DNSEP were 38.1±4.0 ms (3.0±1.9 uV) and 40.5±3.4 ms (2.8±1.6 uV) before circumcision, respectively; and 42.8±3.3 ms (2.8±1.6 uV) and 40.5±4.1 ms (2.4±1.2 uV) in the follow-up end point after circumcision. Only the latencies of GPSEP showed significant prolongation before and after circumcision (P<0.001). The ejaculation time improvement after circumcision is so small, and equal to placebo response, therefore it could not be interpreted as a therapeutic method in men with PE.

  10. Evaluation of Cervical Vestibular Evoked Myogenic Potentials in Patients with Migraine.

    Directory of Open Access Journals (Sweden)

    Mehmet Tecellioğlu

    2013-12-01

    Full Text Available OBJECTIVE: : Recent studies have shown that in the pathogenesis of migraine, the brain stem may contribute via different mechanisms. Although vestibular evoked myogenic potentials (VEMP testing is mainly used in otologic diseases, it is also used in especially neurological diseases affecting the brain stem such as stroke and multipl sclerosis in the literature. Studies involving VEMP testing in patients with migraine are novel and few in number. The purpose of this study was to evaluate whether VEMP values in patients with migraine provide additional information regarding pathogenesis. METHODS: This study included 52 patients with migraine and 52 control subjects. In both patients and controls, VEMP examination was performed using click stimuli, and all responses were recorded for both portions of the sternocleidomastoid muscle. Latency, amplitude, and threshold values of the p1–n1 wave were compared between the two groups. RESULTS: The amplitude of the left p1 was 4.47±3.52 µv in patients and 6.15±4.79 µv in the controls, and the difference was statistically significant (p: 0.044. On the left, the average difference in the p1–n1 amplitude was 9.04±6.13 µv in patients and 12.03±7.79 µv in the controls; this difference was also statistically significant (p: 0.032. CONCLUSION: The available studies on the pathophysiology of migraine show that the brain stem is particularly affected at the upper part. However, VEMP testing is mainly a technique for assessment of neuronal pathway starting from the saccula-macula and finishing at the sternocleidomastoid muscle in the lower brain stem. In this study, the only significant differences in amplitude were found in left-p1 and p1-n1. The results of our study show that in patients with migraine, neuroanatomical structures in the lower brain stem can be asymmetrically affected.

  11. The Effect of Magnesium on Visual Evoked Potentials in L-NAME-Induced Hypertensive Rats.

    Science.gov (United States)

    Ozsoy, Ozlem; Aras, Sinem; Ulker Karadamar, Pinar; Nasircilar Ulker, Seher; Kocer, Gunnur; Senturk, Umit Kemal; Basrali, Filiz; Yargicoglu, Piraye; Ozyurt, Dilek; Agar, Aysel

    2016-08-01

    In the literature, although there are many studies regarding complications of hypertension, information concerning its influence on visual evoked potentials (VEPs) is limited. This study aims to clarify the possible therapeutic effects of the preferential magnesium (Mg) treatment on VEPs in an experimental hypertension model. Rats were divided into four groups as follows: control, Mg treated (Mg), N(omega)-nitro-L-arginine methyl ester (L-NAME) hypertension, and L-NAME hypertension + Mg treated (L-NAME + Mg). Hypertension was induced by L-NAME which was given to rats orally over 6 weeks (25 mg/kg/day in drinking water). A magnesium-enriched diet (0.8 g/kg) was given to treatment groups for 6 weeks. Systolic blood pressure (SBP) was determined by using the tail-cuff method. Flash VEPs were recorded. Our results revealed that the SBP was significantly increased in the L-NAME group compared to control. Magnesium treatment significantly attenuated SBP in the hypertensive rats compared to the L-NAME group. The mean latencies of P1, N1, P2, N2, and P3 components were significantly prolonged in hypertensive rats compared to control. Treatment with Mg provided a significant decrease in the latencies of P1, N1, P2, N2, and P3 potentials in the L-NAME + Mg group compared to the L-NAME group. Plasma Mg levels were increased in the L-NAME + Mg group compared to the L-NAME group. No change was detected in the Mg levels of the brains in all experimental groups. Magnesium treatment had no effect on the brain nitrate/nitrite and thiobarbituric acid-reactive substances (TBARS) levels in hypertensive rats compared to non-treated rats. There was a positive correlation between the brain TBARS levels and SBP of the rats. The present study suggests that Mg supplementation has the potential to prevent VEP changes in the L-NAME-induced hypertension model. PMID:26701333

  12. Steady-state evoked potentials to study the processing of tactile and nociceptive somatosensory input in the human brain.

    OpenAIRE

    Colon, Elisabeth; Legrain, Valéry; Mouraux, André

    2012-01-01

    The periodic presentation of a sensory stimulus induces, at certain frequencies of stimulation, a sustained electroencephalographic response of corresponding frequency, known as steady-state evoked potentials (SS-EP). In visual, auditory and vibrotactile modalities, studies have shown that SS-EP reflect mainly activity originating from early, modality-specific sensory cortices. Furthermore, it has been shown that SS-EP have several advantages over the recording of transient event-related brai...

  13. EVALUATION OF OPTIC AND VESTIBULOCOCHLEAR NERVE INVOLVEMENT IN TYPE 2 DIABETES MELLITUS PATIENTS BY USING EVOKED POTENTIAL

    OpenAIRE

    Arrthy S, Vinodha R, Saravanan S

    2015-01-01

    Background and Objectives: Cranial neuropathy is one of the common late complications of Diabetes Mellitus(DM), including distal symmetric sensory polyneuropathy and peripheral neuropathy(PN). Though many studies support the involvement of Cranial nerves III, VI and VII in diabetic patients, little was known about the involvement of II & VIII nerve. The goal of this study was to evaluate the involvement of optic nerve and vestibulocochlear nerve using Visual Evoked potential (VEP) and Brainst...

  14. Comparison of the reliability of multifocal visual evoked cortical potentials generated by pattern reversal and pattern pulse stimulation

    OpenAIRE

    G.S. Souza; H.B. Schakelford; Moura, A.L.A.; Gomes, B.D.; D.F. Ventura; M.E.C. Fitzgerald; L.C.L. Silveira

    2012-01-01

    This study compared the effectiveness of the multifocal visual evoked cortical potentials (mfVEP) elicited by pattern pulse stimulation with that of pattern reversal in producing reliable responses (signal-to-noise ratio >1.359). Participants were 14 healthy subjects. Visual stimulation was obtained using a 60-sector dartboard display consisting of 6 concentric rings presented in either pulse or reversal mode. Each sector, consisting of 16 checks at 99% Michelson contrast and 80 cd/m² mean lu...

  15. Vestibular evoked myogenic potentials: an overview Potencial evocado miogênico vestibular: uma visão geral

    OpenAIRE

    Renato Cal; Fayez Bahmad Jr.

    2009-01-01

    The vestibular evoked myogenic potential (VEMP) test is a relatively new diagnostic tool that is in the process of being investigated in patients with specific vestibular disorders. Briefly, the VEMP is a biphasic response elicited by loud clicks or tone bursts recorded from the tonically contracted sternocleidomastoid muscle, being the only resource available to assess the function of the saccule and the lower portion of the vestibular nerve. AIM: In this review, we shall highlight the histo...

  16. Evaluation of the neural function of nonhuman primates with spinal cord injury using an evoked potential-based scoring system

    Science.gov (United States)

    Ye, Jichao; Ma, Mengjun; Xie, Zhongyu; Wang, Peng; Tang, Yong; Huang, Lin; Chen, Keng; Gao, Liangbin; Wu, Yanfeng; Shen, Huiyong; Zeng, Yuanshan

    2016-01-01

    Nonhuman primate models of spinal cord injury (SCI) have been widely used in evaluation of the efficacy and safety of experimental restorative interventions before clinical trials. However, no objective methods are currently available for the evaluation of neural function in nonhuman primates. In our long-term clinical practice, we have used evoked potential (EP) for neural function surveillance during operation and accumulated extensive experience. In the present study, a nonhuman primate model of SCI was established in 6 adult cynomologus monkeys through spinal cord contusion injury at T8–T9. The neural function before SCI and within 6 months after SCI was evaluated based on EP recording. A scoring system including somatosensory evoked potentials (SSEPs) and transcranial electrical stimulation-motor evoked potentials (TES-MEPs) was established for the evaluation of neural function of nonhuman primates with SCI. We compared the motor function scores of nonhuman primates before and after SCI. Our results showed that the EP below the injury level significantly changed during the 6 months after SCI. In addition, a positive correlation was identified between the EP scores and motor function. The EP-based scoring system is a reliable approach for evaluating the motor function changes in nonhuman primates with SCI. PMID:27629352

  17. Comparison of Middle Latency Auditory Evoked Potentials in Learning Disability and Normal 7-12 Year- Old Children

    Directory of Open Access Journals (Sweden)

    Shoreh Jalaei

    2007-12-01

    Full Text Available Background and Aim: Learning disability(LD is one of the most prevalent problems among elementary school children. Approximately 10 percent of all elementary school children suffer from this problem. It has been determined that learning disability is predominantly accompanied with subtle impairment in central auditory nervous system. The main idea of this study was to evaluate middle latency auditory evoked potential (MLAEPs in learning disabled children. Materials and Method: This cross-sectional study investigated middle latency auditory evoked potential in children with learning disability (n = 31 compared to normal children (n = 31. Latencies and amplitudes of MLAEPs results with different stimulus intensity and binaural stimulation were compared between two groups. Results: Compared to control group, learning disabled children exhibited smaller amplitudes for all the components except the right ear Na and Pa. There is no significant difference between two groups for latencies of the components. Conclusion: It seems that middle latency auditory evoked potential may be useful in diagnosis and evaluation of learning disabled children although more investigation is required.

  18. Population synaptic potentials evoked in lumbar motoneurons following stimulation of the nucleus reticularis gigantocellularis during carbachol-induced atonia.

    Science.gov (United States)

    Yamuy, J; Jiménez, I; Morales, F; Rudomin, P; Chase, M

    1994-03-14

    The effect of electrical stimulation of the medullary nucleus reticularis gigantocellularis (NRGc) on lumbar spinal cord motoneurons was studied in the decerebrate cat using sucrose-gap recordings from ventral roots. The NRGc was stimulated ipsi- and contralaterally before and during atonia elicited by the microinjection of carbachol into the pontine reticular formation. Prior to carbachol administration, the NRGc-induced response recorded from the sucrose-gap consisted of two consecutive excitatory population synaptic potentials followed by a long-lasting, small amplitude inhibitory population synaptic potential. Following carbachol injection, the same NRGc stimulus evoked a distinct, large amplitude inhibitory population synaptic potential, whereas the excitatory population synaptic potentials decreased in amplitude. In addition, after carbachol administration, the amplitude of the monosynaptic excitatory population synaptic potential, which was evoked by stimulation of group Ia afferents in hindlimb nerves, was reduced by 18 to 43%. When evoked at the peak of the NRGc-induced inhibitory response, this potential was further decreased in amplitude. Systemic strychnine administration (0.07-0.1 mg/kg, i.v.) blocked the NRGc-induced inhibitory population synaptic potential and promoted an increase in the amplitude of the excitatory population synaptic potentials induced by stimulation of the NRGc and group Ia afferents. These data indicate that during the state of carbachol-induced atonia, the NRGc effects on ipsi- and contralateral spinal cord motoneurons are predominantly inhibitory and that glycine is likely to be involved in this inhibitory process. These results support the hypothesis that the nucleus reticularis gigantocellularis is part of the system responsible for state-dependent somatomotor inhibition that occurs during active sleep. PMID:8205484

  19. INFLUENCE OF DANCE TRAINING ON SACCULOCOLLIC PATHWAY: VESTIBULAR EVOKED MYOGENIC POTENTIALS (VEMP AS AN OBJECTIVE TOOL

    Directory of Open Access Journals (Sweden)

    Swathi

    2013-10-01

    Full Text Available ABSTRACT : Auditory system is shaped by experience and training. Training (s ensory experience induces neurophysiologic changes & plasticity in normal hearing individuals, hearing loss patients, hearing aid users and cochlear implanted subjects. Not only speech stimulus, but music also brings about functional and structural organi zation of the brain in musician compared to non - musicians. The Vestibular evoked myogenic potentials (VEMP are a biphasic inhibitory response elicited by loud clicks or tone bursts recorded from the tonically contracted sternocleidomastoid muscle (SCM, b eing the only resource available to assess the function of the saccule and the inferior vestibular nerve ( sacculocollic pathway DESIGN: prospective study. AIM : The present study was conducted with an aim of studying plasticity of the sacculocollic pathway in professional dancers who are receiving dance training. METHOD : Two groups of subjects participated for the study a experimental group; b control group, experimental group was further divided in to two subgroups - Professional dancers who have received training in salsa as well as Bharath natyam. Experimental group consisted of total 40 subjects (80 ears, 20 (40 ears in each subgroup. Control group consisted of 40 individuals who have not received any professional training in dance (80 ears . RESULT: Results showed that there was statistically increase in amplitude of P13, N23 and P13 - N23 as well as early latency of P13, and N23 in professional dancers compared to the control group. The difference in amplitude and latency between the two groups was att ributed to plasticity of sacculocollic pathway in dancers. CONCLUSION: during aging process there is considerable deterioration of balance capability, loss of balance is a major risk factor for falls in middle aged and elderly people , to slow this deterior ation of balance one should gradually and continuously stimulate balance through motor activity, People

  20. The effect of lead on brainstem auditory evoked potentials in children

    Institute of Scientific and Technical Information of China (English)

    邹朝春; 赵正言; 唐兰芳; 陈志敏; 杜立中

    2003-01-01

    Objective To determine whether lead affects brainstem auditory evoked potentials (BAEPs) in low-to-moderate lead exposed children. Methods BAEPs were recorded from 114 asymptomatic children aged 1-6 years. Average values were calculated for peak latency (PL) and amplitude (Amp). Whole blood lead (PbB) levels were assessed by graphite furnace atomic absorption spectroscopy. Based on their PbB levels, subjects were divided into low lead (PbB<100 μg/L) and high lead subgroups (PbB ≥100 μg/L). Results The PbB levels of the 114 subjects ranged from 32.0 to 380.0 μg/L in a positively skewed distribution. The median of PbB levels was 90.0 μg/L while the arithmetic average was 88.0 μg/L. Of the subjects, 43.0% (49/114) had levels equal to or greater than 100 μg/L. Bilateral PLs Ⅰ, Ⅴ, and Ⅲ of the left ear in the high lead subgroup were significantly longer than those in the low lead subgroup (P<0.05). A positive correlation was found between PbB levels and bilateral PLs Ⅰ, Ⅴ and Ⅲ of the left ear (P<0.05), after controlling for age and gender as confounding factors. A significant and positive correlation between PbB levels and PL Ⅰ of the left ear, even when PbB levels were lower than 100 μg/L, in the low subgroup (r=0.295, P=0.019) was also found.Conclusions Lead poisoning in children younger than 6 years old is a very serious problem to which close attention should be paid. The indications that lead prolongs partial PLs may imply that lead, even at PbB levels lower than 100 μg/L, impairs both the peripheral and the central portions of the auditory system. BAEPs may be a sensitive detector of subclinical lead exposure effects on the nervous system in children.

  1. Electroencephalogram and brainstem auditory evoked potential in 539 patients with central coordination disorder

    Institute of Scientific and Technical Information of China (English)

    Huijia Zhang; Hua Yan; Paoqiu Wang; Jihong Hu; Hongtao Zhou; Rong Qin

    2008-01-01

    BACKGROUND: Electroencephalogram (EEG) and brainstem auditory evoked potential (BAEP) are objective non-invasive means of measuring brain electrophysiology.OBJECTIVE: To analyze the value of EEG and BAEP in early diagnosis, treatment and prognostic evaluation of central coordination disorder.DESIGN, TIME AND SETTING: This case analysis study was performed at the Rehabilitation Center of Hunan Children's Hospital from January 2002 to January 2006.PARTICIPANTS: A total of 593 patients with severe central coordination disorder, comprising 455 boys and 138 girls, aged 1--6 months were enrolled for this study.METHODS: EEG was monitored using electroencephalography. BAEP was recorded using a Keypoint electromyogram device. Intelligence was tested by professionals using the Gesell scale.MAIN OUTCOME MEASURES: (1) The rate of abnormal EEG and BAEP, (2) correlation of abnormalities of EEG and BAEP with associated injuries, (3) correlation of abnormalities of EEG and BAEP with high risk factors.RESULTS: The rate of abnormal EEG was 68.6% (407/593 patients), and was increased in patients who also had mental retardation (P < 0.05). The rate of abnormal BAEP was 21.4% (127/593 patients). These 127 patients included 67 patients (52.8%) with peripheral auditory damage and 60 patients (47.2%) with central and mixed auditory damage. The rate of abnormal BAEP was significantly increased in patients who also had mental retardation (P < 0.01). Logistic regression analysis showed that asphyxia (P < 0.05), jaundice,preterm delivery, low birth weight and the umbilical cord around the neck were closely correlated with abnormal EEG in patients with central coordination disorder. Intracranial hemorrhage, jaundice (P < 0.05),low birth weight and intrauterine infection (P < 0.05) were closely correlated with abnormal BAEP in patients with central coordination disorder.CONCLUSION: Central coordination disorder is often associated with abnormal EEG and BAEP. The rate of EEG or BAEP abnormality

  2. The effect of anxiety on respiratory sensory gating measured by respiratory-related evoked potentials

    OpenAIRE

    Chan, Pei-Ying S.; von Leupoldt, Andreas; Bradley, Margaret M.; Lang, Peter J.; Davenport, Paul W.

    2012-01-01

    Respiratory sensory gating is evidenced by decreased amplitudes of the respiratory-related evoked poten-Received 24 September 2011 tials (RREP) N1 peak for the second (S2) compared to the first occlusion (S1) when two paired occlusions Accepted 2 July 2012 are presented with a 500-millisecond (ms) inter-stimulus-interval during one inspiration. Because anxiety is prevalent in respiratory diseases and associated with altered respiratory perception, we tested whether anxiety can modulate indivi...

  3. Brainstem Auditory Evoked Potentials Suggest a Role for the Ventral Cochlear Nucleus in Tinnitus

    OpenAIRE

    Gu, Jianwen Wendy; Herrmann, Barbara S.; Levine, Robert A.; Melcher, Jennifer R.

    2012-01-01

    Numerous studies have demonstrated elevated spontaneous and sound-evoked brainstem activity in animal models of tinnitus, but data on brainstem function in people with this common clinical condition are sparse. Here, auditory nerve and brainstem function in response to sound was assessed via auditory brainstem responses (ABR) in humans with tinnitus and without. Tinnitus subjects showed reduced wave I amplitude (indicating reduced auditory nerve activity) but enhanced wave V (reflecting eleva...

  4. Characteristics of brainstem auditory evoked potential of neonates with mild or moderate hyperbilirubinemia

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    BACKGROUND: Brainstem auditory evoked potential (BAEP) has been widely used to evaluate the functional integrity and development of injured auditory system and brain, especially to objectively evaluate the function of auditory system and brain stem of very young babies, such as neonates and sick babies.OBJECTIVE: To observe the changes of BAEP of neonates with hyperbilirubinemia, and to investigate the relationship of bilirubin concentration and BAEP.DESIGN: An observation experiment.SETTING: Department of Pediatrics, the 309 Clinical Division, General Hospital of Chinese PLA.PARTICIPANTS: Fifty-eight neonates with mild or moderate hyperbilirubinemia exhibiting jaundice within 24 hours after born, who received the treatment in the Department of Pediatrics, the 309 Clinical Division, General Hospital of Chinese PLA between January 2004 and May 2007, were recruited in this study. The involved neonates, 31 boys and 27 girls, had gestational age of 37 to 46 weeks. They had no history of birth asphyxia, and were scored 8 to 10 points when born. Written informed consents of examination and treatment were obtained from the guardians of the neonates. This study was approved by the Hospital Ethics Committee. According to serum total bilirubin value, the neonates were assigned into 3 groups: low-concentration bilirubin group (n =16), moderate-concentration bilirubin group (n =27) and high-concentration bilirubin group (n =15). According to mean daily bilirubin increase, the subjects were sub-assigned into bilirubin rapid increase group (n =39) and bilirubin slow increase group (n =19).METHODS: After admission, all the neonates received drug treatment. Meanwhile, their 116 ears were examined with a myoelectricity evoked potential equipment (KEYPOINT) in latency, wave duration,amplitude and wave shape differentiation of each wave of BAEP. BAEP abnormal type was observed and abnormal rate of BAEP was calculated.MAIN OUTCOME MEASURES: ① Abnormal rate and abnormal type of BAEP

  5. Towards an optimization of stimulus parameters for brain-computer interfaces based on steady state visual evoked potentials.

    Directory of Open Access Journals (Sweden)

    Anna Duszyk

    Full Text Available 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.

  6. Dipole source analyses of laser evoked potentials obtained from subdural grid recordings from primary somatic sensory cortex.

    Science.gov (United States)

    Baumgärtner, Ulf; Vogel, Hagen; Ohara, Shinji; Treede, Rolf-Detlef; Lenz, Fred

    2011-08-01

    The cortical potentials evoked by cutaneous application of a laser stimulus (laser evoked potentials, LEP) often include potentials in the primary somatic sensory cortex (S1), which may be located within the subdivisions of S1 including Brodmann areas 3A, 3B, 1, and 2. The precise location of the LEP generator may clarify the pattern of activation of human S1 by painful stimuli. We now test the hypothesis that the generators of the LEP are located in human Brodmann area 1 or 3A within S1. Local field potential (LFP) source analysis of the LEP was obtained from subdural grids over sensorimotor cortex in two patients undergoing epilepsy surgery. The relationship of LEP dipoles was compared with dipoles for somatic sensory potentials evoked by median nerve stimulation (SEP) and recorded in area 3B (see Baumgärtner U, Vogel H, Ohara S, Treede RD, Lenz FA. J Neurophysiol 104: 3029-3041, 2010). Both patients had an early radial dipole in S1. The LEP dipole was located medial, anterior, and deep to the SEP dipole, which suggests a nociceptive dipole in area 3A. One patient had a later tangential dipole with positivity posterior, which is opposite to the orientation of the SEP dipole in area 3B. The reversal of orientations between modalities is consistent with the cortical surface negative orientation resulting from superficial termination of thalamocortical neurons that receive inputs from the spinothalamic tract. Therefore, the present results suggest that the LEP may result in a radial dipole consistent with a generator in area 3A and a putative later tangential generator in area 3B. PMID:21593389

  7. Compound action potentials recorded in the human spinal cord during neurostimulation for pain relief.

    Science.gov (United States)

    Parker, John L; Karantonis, Dean M; Single, Peter S; Obradovic, Milan; Cousins, Michael J

    2012-03-01

    Electrical stimulation of the spinal cord provides effective pain relief to hundreds of thousands of chronic neuropathic pain sufferers. The therapy involves implantation of an electrode array into the epidural space of the subject and then stimulation of the dorsal column with electrical pulses. The stimulation depolarises axons and generates propagating action potentials that interfere with the perception of pain. Despite the long-term clinical experience with spinal cord stimulation, the mechanism of action is not understood, and no direct evidence of the properties of neurons being stimulated has been presented. Here we report novel measurements of evoked compound action potentials from the spinal cords of patients undergoing stimulation for pain relief. The results reveal that Aβ sensory nerve fibres are recruited at therapeutic stimulation levels and the Aβ potential amplitude correlates with the degree of coverage of the painful area. Aβ-evoked responses are not measurable below a threshold stimulation level, and their amplitude increases with increasing stimulation current. At high currents, additional late responses are observed. Our results contribute towards efforts to define the mechanism of spinal cord stimulation. The minimally invasive recording technique we have developed provides data previously obtained only through microelectrode techniques in spinal cords of animals. Our observations also allow the development of systems that use neuronal recording in a feedback loop to control neurostimulation on a continuous basis and deliver more effective pain relief. This is one of numerous benefits that in vivo electrophysiological recording can bring to a broad range of neuromodulation therapies. PMID:22188868

  8. Short latency compound action potentials from mammalian gravity receptor organs

    Science.gov (United States)

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

    1999-01-01

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

  9. The Potential of Deweyan-Inspired Action Research

    OpenAIRE

    Stark, Jody L.

    2014-01-01

    In its broadest sense, pragmatism could be said to be the philosophical orientation of all action research. Action research is characterized by research, action, and participation grounded in democratic principles and guided by the aim of social improvement. Furthermore, action research is an active process of inquiry that does not admit separation between action and reflection or theory and practice. This paper considers the potential of action research informed specifically by Deweyan pragm...

  10. A novel method of brainstem auditory evoked potentials using complex verbal stimuli

    Directory of Open Access Journals (Sweden)

    Sophia N Kouni

    2014-01-01

    Full Text Available 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.

  11. Dynamic causal modeling of touch-evoked potentials in the rubber hand illusion.

    Science.gov (United States)

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

    2016-09-01

    The neural substrate of bodily ownership can be disclosed by the rubber hand illusion (RHI); namely, the illusory self-attribution of an artificial hand that is induced by synchronous tactile stimulation of the subject's hand that is hidden from view. Previous studies have pointed to the premotor cortex (PMC) as a pivotal area in such illusions. To investigate the effective connectivity between - and within - sensory and premotor areas involved in bodily perceptions, we used dynamic causal modeling of touch-evoked responses in 13 healthy subjects. Each subject's right hand was stroked while viewing their own hand ("REAL"), or an artificial hand presented in an anatomically plausible ("CONGRUENT") or implausible ("INCONGRUENT") position. Bayesian model comparison revealed strong evidence for a differential involvement of the PMC in the generation of touch-evoked responses under the three conditions, confirming a crucial role of PMC in bodily self-attribution. In brief, the extrinsic (forward) connection from left occipital cortex to left PMC was stronger for CONGRUENT and INCONGRUENT as compared to REAL, reflecting the augmentation of bottom-up visual input when multisensory integration is challenged. Crucially, intrinsic connectivity in the primary somatosensory cortex (S1) was attenuated in the CONGRUENT condition, during the illusory percept. These findings support predictive coding models of the functional architecture of multisensory integration (and attenuation) in bodily perceptual experience. PMID:27241481

  12. Brainstem auditory evoked potentials in a case of 'Manto syndrome', or spasmodic torticollis with thoracic outlet syndrome.

    Science.gov (United States)

    Disertori, B; Ducati, A; Piazza, M; Pavani, M

    1982-12-01

    A case of spasmodic torticollis with thoracic outlet syndrome observed for over 18 months is presented and discussed. Maximal head rotation (determining backward gaze) was associated with compression of the brachial plexus between the scaleni muscles and motor, sensory and trophic troubles in the hand. This new syndrome is called after the diviner Manto, quoted by Dante Alighieri in his 'Divina Commedia' (Inferno, XX, 52-56). The etiology was ascribed to subacute toxic effects of methylparathion. Brainstem Auditory Evoked Potentials (BAEPs) demonstrated severe brainstem involvement, maximal in the mesencephalic structures. Clinical and neurophysiological data improved on treatment with L-5-hydroxytryptophan. Finally, BAEPs returned to normal.

  13. Identification of causal relations between haemodynamic variables, auditory evoked potentials and isoflurane by means of fuzzy logic

    DEFF Research Database (Denmark)

    Jensen, E W; Nebot, A; Caminal, P;

    1999-01-01

    The aim of this study was to identify a possible relationship between haemodynamic variables, auditory evoked potentials (AEP) and inspired fraction of isoflurane (ISOFl). Two different models (isoflurane and mean arterial pressure) were identified using the fuzzy inductive reasoning (FIR......) methodology. A fuzzy model is able to identify non-linear and linear components of a causal relationship by means of optimization of information content of available data. Nine young female patients undergoing hysterectomy under general anaesthesia were included. Mean arterial pressure (MAP), heart rate (HR...

  14. Change in Speech Perception and Auditory Evoked Potentials over Time after Unilateral Cochlear Implantation in Postlingually Deaf Adults.

    Science.gov (United States)

    Purdy, Suzanne C; Kelly, Andrea S

    2016-02-01

    Speech perception varies widely across cochlear implant (CI) users and typically improves over time after implantation. There is also some evidence for improved auditory evoked potentials (shorter latencies, larger amplitudes) after implantation but few longitudinal studies have examined the relationship between behavioral and evoked potential measures after implantation in postlingually deaf adults. The relationship between speech perception and auditory evoked potentials was investigated in newly implanted cochlear implant users from the day of implant activation to 9 months postimplantation, on five occasions, in 10 adults age 27 to 57 years who had been bilaterally profoundly deaf for 1 to 30 years prior to receiving a unilateral CI24 cochlear implant. Changes over time in middle latency response (MLR), mismatch negativity, and obligatory cortical auditory evoked potentials and word and sentence speech perception scores were examined. Speech perception improved significantly over the 9-month period. MLRs varied and showed no consistent change over time. Three participants aged in their 50s had absent MLRs. The pattern of change in N1 amplitudes over the five visits varied across participants. P2 area increased significantly for 1,000- and 4,000-Hz tones but not for 250 Hz. The greatest change in P2 area occurred after 6 months of implant experience. Although there was a trend for mismatch negativity peak latency to reduce and width to increase after 3 months of implant experience, there was considerable variability and these changes were not significant. Only 60% of participants had a detectable mismatch initially; this increased to 100% at 9 months. The continued change in P2 area over the period evaluated, with a trend for greater change for right hemisphere recordings, is consistent with the pattern of incremental change in speech perception scores over time. MLR, N1, and mismatch negativity changes were inconsistent and hence P2 may be a more robust measure

  15. Cavitron ultrasonic surgical aspirator and visual evoked potential monitoring for chiasmal gliomas in children. Report of two cases.

    Science.gov (United States)

    Albright, A L; Sclabassi, R J

    1985-07-01

    The Cavitron ultrasonic surgical aspirator (CUSA) and intraoperative visual evoked potentials (VEP's) were found to be helpful in treating two children with difficult chiasmal gliomas. Approximately 60% of one tumor and 85% of the other was resected without change in the intraoperative VEP's and with no change in postoperative visual fields or acuity. The CUSA-VEP technique is useful in the infant to "buy time" for brain maturation, delaying or obviating subsequent radiotherapy. This approach may be helpful in the older child to reduce the tumor burden for subsequent chemotherapy. Chiasmal gliomas can be subtotally resected with the CUSA while visual function is monitored by intraoperative VEP's.

  16. Deviation of somatosensory evoked potential and lateral dominance of spike activity in iron-induced epileptic cortex of the rat.

    Directory of Open Access Journals (Sweden)

    Hattori,Yukio

    1983-10-01

    Full Text Available A chronic epileptic focus was induced by a microinjection of ferric chloride solution into the sensorimotor cortex of rats. Two types of somatosensory evoked potentials (SEPs were recorded from the cortex near the injection site. In animals showing an initial positive-negative biphasic SEP, spikes appeared in electrocorticograms (ECoGs more frequently on the side ipsilateral to the injection site than on the contralateral side, whereas in animals showing an initial negative monophasic SEP, spikes appeared more frequently on the contralateral side.

  17. Change in somatosensory evoked potential in the rat recorded at the hemisphere with iron-induced epileptic focus.

    Directory of Open Access Journals (Sweden)

    Hattori,Yukio

    1981-12-01

    Full Text Available In rats, microinjection of FeCl3 solution into the left sensorimotor cortex was performed to induce a chronic epileptic focus. One month or more after the microinjection, electrocutaneous stimuli were applied to part of the wrist joint and 50 consecutive somatosensory evoked potentials (SEPs were averaged. SEP from the left cortex showed only an initial negative monophasic deflection while SEP from the contralateral cortex showed a normal configuration with initial positive-negative biphasic deflection in the majority of experimental animals.

  18. Proprioceptive evoked gamma oscillations

    DEFF Research Database (Denmark)

    Arnfred, S.M.; Hansen, Lars Kai; Parnas, J.;

    2007-01-01

    A proprioceptive stimulus consisting of a weight change of a handheld load has recently been shown to elicit an evoked potential. Previously, somatosensory gamma oscillations have only been evoked by electrical stimuli. We conjectured that a natural proprioceptive stimulus also would be able...

  19. Proprioceptive evoked gamma oscillations

    DEFF Research Database (Denmark)

    Arnfred, Sidse M; Hansen, Lars Kai; Parnas, Josef;

    2007-01-01

    A proprioceptive stimulus consisting of a weight change of a handheld load has recently been shown to elicit an evoked potential. Previously, somatosensory gamma oscillations have only been evoked by electrical stimuli. We conjectured that a natural proprioceptive stimulus also would be able to...

  20. INFLUENCE OF ACUPUNCTURE (“JIN‘S SAN ZHEN”) ON BRAINSTEM EVOKED POTENTIALS IN MENTAL RETARDATION CHILDREN

    Institute of Scientific and Technical Information of China (English)

    袁青; 马瑞玲; 等

    2002-01-01

    Objective:To investigate the effect of acupuncture(“JIN's San Zhen”)on infantile mental retardation (MR).Methods:44 cases of MR children were attributed to treatment group and 3 normal children to control group.P3(event-related potential) and brainstem evoked potentials were used as the indexes.Acupoints “Si-shen Zhen”,“Head Zhi San Zhen”,“Hand Zhi San Zhen”,“Foot Zhi San Zhen” were unctured with filiform needles,and stimulated by manipulating the needle once every 5minutes with uniform reinforcing-reducing method.The treatment was conducted once daily,6 times every week,with 4 months being a therapeutic course.Results:In comparison with normal children,the latency of P3 was longer and its amplitude lower in MR children.After 4 months' acupuncture treatment,the latency was shortened and the smplitude increased significantly in comparison with pre-treatment (P<0.01,0.05).Results of the total intelligence quotient(TIQ) evaluation showed a 70.3% coincidence rate compared with improvement of P3.Conclusion:Changes of P3 and BAEP(brain auditory evoked potential) after acupuncture treatment may be related to the effect of “JIN's San Zhen” in bettering clinical symptoms and signs of MR infantile patients.

  1. High-frequency combination coding-based steady-state visual evoked potential for brain computer interface

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Feng; Zhang, Xin; Xie, Jun; Li, Yeping; Han, Chengcheng; Lili, Li; Wang, Jing [School of Mechanical Engineering, Xi’an Jiaotong University, Xi’an 710049 (China); Xu, Guang-Hua [School of Mechanical Engineering, Xi’an Jiaotong University, Xi’an 710049 (China); State Key Laboratory for Manufacturing Systems Engineering, Xi’an Jiaotong University, Xi’an 710054 (China)

    2015-03-10

    This study presents a new steady-state visual evoked potential (SSVEP) paradigm for brain computer interface (BCI) systems. The goal of this study is to increase the number of targets using fewer stimulation high frequencies, with diminishing subject’s fatigue and reducing the risk of photosensitive epileptic seizures. The new paradigm is High-Frequency Combination Coding-Based High-Frequency Steady-State Visual Evoked Potential (HFCC-SSVEP).Firstly, we studied SSVEP high frequency(beyond 25 Hz)response of SSVEP, whose paradigm is presented on the LED. The SNR (Signal to Noise Ratio) of high frequency(beyond 40 Hz) response is very low, which is been unable to be distinguished through the traditional analysis method; Secondly we investigated the HFCC-SSVEP response (beyond 25 Hz) for 3 frequencies (25Hz, 33.33Hz, and 40Hz), HFCC-SSVEP produces n{sup n} with n high stimulation frequencies through Frequence Combination Code. Further, Animproved Hilbert-huang transform (IHHT)-based variable frequency EEG feature extraction method and a local spectrum extreme target identification algorithmare adopted to extract time-frequency feature of the proposed HFCC-SSVEP response.Linear predictions and fixed sifting (iterating) 10 time is used to overcome the shortage of end effect and stopping criterion,generalized zero-crossing (GZC) is used to compute the instantaneous frequency of the proposed SSVEP respondent signals, the improved HHT-based feature extraction method for the proposed SSVEP paradigm in this study increases recognition efficiency, so as to improve ITR and to increase the stability of the BCI system. what is more, SSVEPs evoked by high-frequency stimuli (beyond 25Hz) minimally diminish subject’s fatigue and prevent safety hazards linked to photo-induced epileptic seizures, So as to ensure the system efficiency and undamaging.This study tests three subjects in order to verify the feasibility of the proposed method.

  2. Cortical configuration by stimulus onset visual evoked potentials (SO-VEPs) predicts performance on a motion direction discrimination task.

    Science.gov (United States)

    Zalar, Bojan; Martin, Tim; Kavcic, Voyko

    2015-06-01

    The slowing of information processing, a hallmark of cognitive aging, has several origins. Previously we reported that in a motion direction discrimination task, older as compared to younger participants showed prolonged non-decision time, an index of an early perceptual stage, while in motion onset visual evoked potentials (MO-VEPs) the P1 component was enhanced and N2 was diminished. We did not find any significant correlations between behavioral and MO-VEP measures. Here, we investigated the role of age in encoding and perceptual processing of stimulus onset visually evoked potentials (SO-VEPs). Twelve healthy adults (age55years) performed a motion direction discrimination task during EEG recording. Prior to motion, the stimulus consisted of a static cloud of white dots on a black background. As expected, SO-VEPs evoked well defined P1, N1, and P2 components. Elderly participants as compared to young participants showed increased P1 amplitude while their P2 amplitude was reduced. In addition elderly participants showed increased latencies for P1 and N1 components. Contrary to the findings with MO-VEPs, SO-VEP parameters were significant predictors of average response times and diffusion model parameters. Our electrophysiological results support the notion that slowing of information processing in older adults starts at the very beginning of encoding in visual cortical processing, most likely in striate and extrastriate visual cortices. More importantly, the earliest SO-VEP components, possibly reflecting configuration of visual cortices and encoding processes, predict subsequent prolonging and tardiness of perceptual and higher-level cognitive processes.

  3. Auditory evoked potentials to spectro-temporal modulation of complex tones in normal subjects and patients with severe brain injury.

    Science.gov (United States)

    Jones, S J; Vaz Pato, M; Sprague, L; Stokes, M; Munday, R; Haque, N

    2000-05-01

    In order to assess higher auditory processing capabilities, long-latency auditory evoked potentials (AEPs) were recorded to synthesized musical instrument tones in 22 post-comatose patients with severe brain injury causing variably attenuated behavioural responsiveness. On the basis of normative studies, three different types of spectro-temporal modulation were employed. When a continuous 'clarinet' tone changes pitch once every few seconds, N1/P2 potentials are evoked at latencies of approximately 90 and 180 ms, respectively. Their distribution in the fronto-central region is consistent with generators in the supratemporal cortex of both hemispheres. When the pitch is modulated at a much faster rate ( approximately 16 changes/s), responses to each change are virtually abolished but potentials with similar distribution are still elicited by changing the timbre (e.g. 'clarinet' to 'oboe') every few seconds. These responses appear to represent the cortical processes concerned with spectral pattern analysis and the grouping of frequency components to form sound 'objects'. Following a period of 16/s oscillation between two pitches, a more anteriorly distributed negativity is evoked on resumption of a steady pitch. Various lines of evidence suggest that this is probably equivalent to the 'mismatch negativity' (MMN), reflecting a pre-perceptual, memory-based process for detection of change in spectro-temporal sound patterns. This method requires no off-line subtraction of AEPs evoked by the onset of a tone, and the MMN is produced rapidly and robustly with considerably larger amplitude (usually >5 microV) than that to discontinuous pure tones. In the brain-injured patients, the presence of AEPs to two or more complex tone stimuli (in the combined assessment of two authors who were 'blind' to the clinical and behavioural data) was significantly associated with the demonstrable possession of discriminative hearing (the ability to respond differentially to verbal commands

  4. Action potential broadening in a presynaptic channelopathy

    Science.gov (United States)

    Begum, Rahima; Bakiri, Yamina; Volynski, Kirill E.; Kullmann, Dimitri M.

    2016-07-01

    Brain development and interictal function are unaffected in many paroxysmal neurological channelopathies, possibly explained by homoeostatic plasticity of synaptic transmission. Episodic ataxia type 1 is caused by missense mutations of the potassium channel Kv1.1, which is abundantly expressed in the terminals of cerebellar basket cells. Presynaptic action potentials of small inhibitory terminals have not been characterized, and it is not known whether developmental plasticity compensates for the effects of Kv1.1 dysfunction. Here we use visually targeted patch-clamp recordings from basket cell terminals of mice harbouring an ataxia-associated mutation and their wild-type littermates. Presynaptic spikes are followed by a pronounced afterdepolarization, and are broadened by pharmacological blockade of Kv1.1 or by a dominant ataxia-associated mutation. Somatic recordings fail to detect such changes. Spike broadening leads to increased Ca2+ influx and GABA release, and decreased spontaneous Purkinje cell firing. We find no evidence for developmental compensation for inherited Kv1.1 dysfunction.

  5. Motor-Evoked Potentials in the Lower Back Are Modulated by Visual Perception of Lifted Weight.

    Directory of Open Access Journals (Sweden)

    Frank Behrendt

    Full Text Available Facilitation of the primary motor cortex (M1 during the mere observation of an action is highly congruent with the observed action itself. This congruency comprises several features of the executed action such as somatotopy and temporal coding. Studies using reach-grasp-lift paradigms showed that the muscle-specific facilitation of the observer's motor system reflects the degree of grip force exerted in an observed hand action. The weight judgment of a lifted object during action observation is an easy task which is the case for hand actions as well as for lifting boxes from the ground. Here we investigated whether the cortical representation in M1 for lumbar back muscles is modulated due to the observation of a whole-body lifting movement as it was shown for hand action. We used transcranial magnetic stimulation (TMS to measure the corticospinal excitability of the m. erector spinae (ES while subjects visually observed the recorded sequences of a person lifting boxes of different weights from the floor. Consistent with the results regarding hand action the present study reveals a differential modulation of corticospinal excitability despite the relatively small M1 representation of the back also for lifting actions that mainly involve the lower back musculature.

  6. Teachers in Action Research: Assumptions and Potentials

    Science.gov (United States)

    Li, Yuen-Ling

    2008-01-01

    Research literature has long indicated that action research may stimulate practitioners themselves to actively evaluate the quality of their practice. This study is designed to report the use of action research for the development of early years professional practice by analyzing the pre-project and the post-project video-filmed teaching events.…

  7. Effects of continuous conditioning noise and light on the auditory- and visual-evoked potentials of the guinea pig.

    Science.gov (United States)

    Goksoy, Cuneyt; Demirtas, Serdar; Ates, Kahraman

    2005-11-01

    Neurophysiological studies aiming to explore how the brain integrates information from different brain regions are increasing in the literature. The aim of the present study is to explore intramodal (binaural, binocular) and intermodal (audio-visual) interactions in the guinea pig brain through the observation of changes in evoked potentials by generalized continuous background activity. Seven chronically prepared animals were used in the study and the recordings were made as they were awake. Epidural electrodes were implanted to the skulls by using stereotaxic methods. Continuous light for retinal or continuous white noise for cochlear receptors were used as continuous conditioning stimuli for generalized stimulation. To evoke auditory or visual potentials, click or flash were used as transient imperative stimuli. The study data suggest that (a) white noise applied to one ear modifies the response to click in the contralateral ear which is a binaural interaction; (b) continuous light applied to one eye modifies the response to flash applied to the contralateral eye which is interpreted as a binocular interaction; (c) regardless of the application side, white noise similarly modified the response to flash applied to the either eye connoting a nonspecific effect of white noise on vision, independent from spatial hearing mechanisms; (d) on the other hand, continuous light, in either eye, did not affect the response to click applied to any ear, reminding a 'one-way' interaction that continuous aural stimulation affects visual response.

  8. Changes of evoked potential and expression of nestin in subventricular zones in rats after focal cerebral ischemia

    Institute of Scientific and Technical Information of China (English)

    GAO Jie; WANG Yong-tang; WANG Li-li; ZENG Ling; WU Ya-min; SHAO Yang

    2007-01-01

    Objective:To study the characteristics of latency of somatosensory evoked potential (SEP)and motor evoked potential (MEP) and the expression of nestin in subventricular zones (SVZ) after persistent focal cerebral ischemia in rats. Methods: The model of cerebral ischemia in rats was made by middle cerebral artery occlusion (MCAO). All animals of ischemia were sacrificed after 12 h, 1 d, 3 d, 7 d,and 14 d to observe the changes of latency of SEP and MEP and to detect the expression of nestin, with an immunohistochemical approach. Results: The latencies of P1 (positive wave 1), N1 (negative wave 1) and P2 (positive wave 2) in SEP were significantly prolonged after MCAO. The latencies of N1 and N2 waves in MEP were postponed gradually and no statistical difference of latency of N1 wave was found in rats at 7d and 14 d after MCAO. The expression of nestin increased at 12 h, and showed a significant augmentation at 3 d and peaked at 7 d, then declined slightly at 14 d after MCAO. Conclusion: The cerebral ischemia prolonged the latency of EP waves and the expression of nestin was up-regulated and reached the peak at 7d, showing the ischemia induced the proliferation of nervous stem cells. The SEP and MEP may evaluate the proliferation in SVZ after brain ischemia.

  9. EVALUATION OF OPTIC AND VESTIBULOCOCHLEAR NERVE INVOLVEMENT IN TYPE 2 DIABETES MELLITUS PATIENTS BY USING EVOKED POTENTIAL

    Directory of Open Access Journals (Sweden)

    Arrthy S, Vinodha R, Saravanan S

    2015-09-01

    Full Text Available Background and Objectives: Cranial neuropathy is one of the common late complications of Diabetes Mellitus(DM, including distal symmetric sensory polyneuropathy and peripheral neuropathy(PN. Though many studies support the involvement of Cranial nerves III, VI and VII in diabetic patients, little was known about the involvement of II & VIII nerve. The goal of this study was to evaluate the involvement of optic nerve and vestibulocochlear nerve using Visual Evoked potential (VEP and Brainstem Auditary Evoked Potential (BAEP. Methods: Forty patients with 8 to 12 years duration of type 2 DM in 40 to 60 years age group (Group1 were selected from diabetic outpatient department in Thanjavur medical college hospital and compared with control group (Group 2 who were normal subjects and was age and sex matched. Physical examination and laboratory investigations including fasting glucose, renal functions were done in addition to VEP & BAEP for all groups. P100 latency using VEP and bilateral inter-peak latency IPL I-III, IPL III-V & IPL I-V using BAEP was evaluated and and analyzed for the study group and control group. Result: VEP P100 latency and BAEP bilateral inter-peak latency IPL I-III, IPL III-V & IPL I-V were prolonged in the study group compared to control group. Conclusion: This study concluded the involvement of optic and vestibulocochlear nerve in type 2 DM as the latency was prolonged.

  10. Clinical Use of Skull Tap Vestibular Evoked Myogenic Potentials for the Diagnoses of the Cerebellopontine Angle Tumor Patients

    Directory of Open Access Journals (Sweden)

    Erdem Yavuz

    2014-01-01

    Full Text Available 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.

  11. Physiological origins of evoked magnetic fields and extracellular field potentials produced by guinea-pig CA3 hippocampal slices.

    Science.gov (United States)

    Murakami, Shingo; Zhang, Tongsheng; Hirose, Akira; Okada, Yoshio C

    2002-10-01

    This study examined whether evoked magnetic fields and intra- and extracellular potentials from longitudinal CA3 slices of guinea-pig can be interpreted within a single theoretical framework that incorporates ligand- and voltage-sensitive conductances in the dendrites and soma of the pyramidal cells. The 1991 CA3 mathematical model of R. D. Traub is modified to take into account the asymmetric branching patterns of the apical and basal dendrites of the pyramidal cells. The revised model accounts for the magnitude and waveform of the bi- and triphasic magnetic fields evoked by somatic and apical stimulations, respectively, in the slice in the absence of fast inhibition (blocked by 0.1 mM picrotoxin). The revised model also accounts for selective effects of 4-aminopyridine (4-AP) and tetraethylammonium (TEA), which block the potassium channels of A and C type, respectively, on the slow wave of the magnetic fields. Furthermore, the model correctly predicts the laminar profiles of field potential as well as intracellular potentials in the pyramidal cells produced by two classes of cells - those directly activated and those indirectly (synaptically) activated by the applied external stimulus. The intracellular potentials in this validated model reveal that the spikes and slow waves of the magnetic fields are generated in or near the soma and apical dendrites, respectively. These results demonstrate that a single theoretical framework couched within the modern concepts of cellular physiology provides a unified account of magnetic fields outside the slice, extracellular potentials within the slice and intracellular potentials of the pyramidal cells for CA3.

  12. Single trial predictors for gating motor-imagery brain-computer interfaces based on sensorimotor rhythm and visual evoked potentials

    Directory of Open Access Journals (Sweden)

    Andrew eGeronimo

    2016-04-01

    Full Text Available For brain-computer interfaces (BCIs that utilize visual cues to direct the user, the neural signals extracted by the computer are representative of ongoing processes, visual evoked responses, and voluntary modulation. We proposed to use three brain signatures for predicting success on a single trial of a BCI task. The first two features, the amplitude and phase of the pre-trial mu amplitude, were chosen as a correlate for cortical excitability. The remaining feature, related to the visually evoked response to the cue, served as a possible measure of fixation and attention to the task. Of these three features, mu rhythm amplitude over the central electrodes at the time of cue presentation and to a lesser extent the single trial visual evoked response were correlated with the success on the subsequent imagery task. Despite the potential for gating trials using these features, an offline gating simulation was limited in its ability to produce an increase in device throughput. This discrepancy highlights a distinction between the identification of predictive features, and the use of this knowledge in an online BCI. Using such a system, we cannot assume that the user will respond similarly when faced with a scenario where feedback is altered by trials that are gated on a regular basis. The results of this study suggest the possibility of using individualized, pre-task neural signatures for personalized and asynchronous (self-paced BCI applications, although these effects need to be quantified in a real-time adaptive scenario in a future study.

  13. Action potential initiation in the hodgkin-huxley model.

    OpenAIRE

    Colwell, Lucy J; Brenner, Michael P.

    2009-01-01

    A recent paper of B. Naundorf et al. described an intriguing negative correlation between variability of the onset potential at which an action potential occurs (the onset span) and the rapidity of action potential initiation (the onset rapidity). This correlation was demonstrated in numerical simulations of the Hodgkin-Huxley model. Due to this antagonism, it is argued that Hodgkin-Huxley-type models are unable to explain action potential initiation observed in cortical neurons in vivo or in...

  14. Spectral action, Weyl anomaly and the Higgs-Dilaton potential

    OpenAIRE

    Andrianov, A.A.(V.A. Fock Department of Theoretical Physics, Saint-Petersburg State University, 1 ul. Ulyanovskaya, St. Petersburg, 198504, Russia); Kurkov, M.A.; Lizzi, Fedele

    2011-01-01

    We show how the bosonic spectral action emerges from the fermionic action by the renormalization group flow in the presence of a dilaton and the Weyl anomaly. The induced action comes out to be basically the Chamseddine-Connes spectral action introduced in the context of noncommutative geometry. The entire spectral action describes gauge and Higgs fields coupled with gravity. We then consider the effective potential and show, that it has the desired features of a broken and an unbroken phase,...

  15. 基于镜像神经元理论的动作观察疗法对缺血性脑卒中患者上肢运动功能及体感诱发电位的影响%The effects of action observation therapy based on mirror neuron theory on upper-extremity motor function and somatosensory evoked potentials after stroke

    Institute of Scientific and Technical Information of China (English)

    曾明; 王晶; 顾旭东; 崔尧; 姚云海; 傅建明; 李亮; 吴华; 尹汉逵

    2013-01-01

    ],波幅分别为[(2.75±1.54)μV和(2.84±1.47) μV、(1.38 ±0.43) μV和(1.51±0.44)μV],治疗4周后的N20潜伏期和治疗8周后的N9、N20潜伏期与治疗前相比,差异有统计学意义(P<0.05),对照组偏瘫侧仅治疗8周后的N20波幅与治疗前相比,差异有统计学意义(P<0.05).结论 基于镜像神经元理论的动作观察疗法可改善早期脑卒中患者的上肢运动功能,改善其SEP.%Objective To explore the effects of action observation therapy based on mirror neuron theory on upper-extremity motor function and somatosensory evoked potentials after stroke.Methods Thirty stroke patients were randomly assigned to an observational group (15 cases) or a control group (15 cases).Both groups received conventional rehabilitation including,for example,good limb positioning,balance training and training in the activities of daily living (ADL).The observational group also received action observation therapy for 8 weeks,10 times per week.Both groups were assessed before treatment with the Fugl-Meyer assessment (FMA),the Barthel index (BI)and somatosensory evoked potentials (SEPs) and then again after 4 and 8 weeks of treatment.Their SEP N9 and N20 latencies were also analyzed.Results The average FMA scores at the 4th week (18.87 ± 6.62) and the 8th week (26.27± 9.22) in the observational group had increased significantly compared with the pre-treatment assessment.The control group's FMA score at the 8th week (20.07 ± 6.77) had also increased significantly compared with pretreatment.But at the 8th week the increase in the average FMA score of the observational group was significantly better than that of the control group.The average BI scores of both groups had increased significantly at both the 4th and the 8th week compared with each group's pre-treatment assessment.There was no significant difference in the increases in BI score between the two groups after 8 weeks of treatment.At both the 4th and the 8th week the N9 and N20 latencies on the

  16. Single-trial detection of visual evoked potentials by common spatial patterns and wavelet filtering for brain-computer interface.

    Science.gov (United States)

    Tu, Yiheng; Huang, Gan; Hung, Yeung Sam; Hu, Li; Hu, Yong; Zhang, Zhiguo

    2013-01-01

    Event-related potentials (ERPs) are widely used in brain-computer interface (BCI) systems as input signals conveying a subject's intention. A fast and reliable single-trial ERP detection method can be used to develop a BCI system with both high speed and high accuracy. However, most of single-trial ERP detection methods are developed for offline EEG analysis and thus have a high computational complexity and need manual operations. Therefore, they are not applicable to practical BCI systems, which require a low-complexity and automatic ERP detection method. This work presents a joint spatial-time-frequency filter that combines common spatial patterns (CSP) and wavelet filtering (WF) for improving the signal-to-noise (SNR) of visual evoked potentials (VEP), which can lead to a single-trial ERP-based BCI.

  17. Determination of Median Nerve Somatosensory Evoked Potentials in 27 Patients with Hemiplegia

    Institute of Scientific and Technical Information of China (English)

    刘雅丽; 尤春景; 黄杰; 刘培玲

    2002-01-01

    Summary: Twenty-seven in-patients with hemiplegia following brain injury were studied by using up per extremity median nerve somatosensory evoked patentials (SVEP), Brunnstrom assessment in hemiplegic hand and assessment of the patients' activities of daily lioing (ADL) (Barthel index). The upper extremity median nerve SEP on the affected and normal sides was determined. By using Kovin dba standard, upper extremity median nerve SEP was graded in accordance with N20. The correla tion between the differences of SEP N20 amplitude and the latencies on the both sides and the Barthel index scores was analyzed. A Spearman correlation analysis was made between the median nerve SEP N20 grades and Brunnstrom stages in hand or ADL on the affected side. The results showed that up per extremity median nerve SEP grades were positively correlated with those of the Brunnstrom stages in hand (r1 =0. 6925, P1<0. 01). The correlation coefficient between SEP N20 grades and patients' ADL grades was r2= 0. 5015, P2<0.01. It was concluded that upper extremity median nerve SEP could be used as a sensitive electrophysiological predictor to clinically assess hemiplegic hand function. SEP N20 might play a role in predicting the ADL of the patients with hemiplegia to some extent, but could not be used as a sensitive predictor to directly observe and predict the ADL of the patients.

  18. Formation mechanism of propagated sensation along the meridians, as verified by cortical somatosensory-evoked potential topographic maps

    Institute of Scientific and Technical Information of China (English)

    Jinsen Xu; Xiaohua Pan; Shuxia Zheng; Xianglong Hu; Zheyan Sa

    2011-01-01

    The peripheral driver stimulating theory states that as a driver passes along a certain meridian during acupuncture; the driver provokes nerve sense devices along the meridian, resulting in the nerve impulse entering the central nervous system. Accordingly, volunteers have reported propagated sensations along the meridians (PSM). The present study was designed to utilize a cortical somatosensory-evoked potential (CSEP) topographic map for determining whether stimulation expansion occurs in somatosensory area I when sensation was provoked in individuals with obvious PSM. The sensation was blocked by mechanical compression, and the sensation was imitated in individuals without PSM. Results revealed a red, high-potential signal in the representative area of the lower limbs in individuals with obvious PSM symptoms when the Gall Bladder Meridian (GBM) sensation passed to the head and face. This representative area was near the middle line of the CSEP topographic map, and a red, high-potential signal, which jumps over the representative area of the upper limbs, also appeared in the representative face area, which was at the external region of the CSEP topographic map. However, in individuals exhibiting no PSM, only a red high-potential signal appeared in the representative lower limb area. When Hegu (LI 4) was stimulated in individuals without PSM, an obvious evoked response appeared only in the representative upper limb area. However, when Hegu was stimulated in individuals exhibiting PSM, the response area was larger in the representative upper limb area and extended to the representative face area. When Guangming (GB 37) was stimulated in PSM individuals, the face representation response disappeared and was confined to a foot representation of the somatosensory area I when PSM was blocked by mechanical pressure. Results suggested that mechanical compression blocked PSM, and corresponding changes were exhibited in the CSEP topographic map. These results provide

  19. Sodium and calcium currents shape action potentials in immature mouse inner hair cells.

    Science.gov (United States)

    Marcotti, Walter; Johnson, Stuart L; Rusch, Alfons; Kros, Corne J

    2003-11-01

    Before the onset of hearing at postnatal day 12, mouse inner hair cells (IHCs) produce spontaneous and evoked action potentials. These spikes are likely to induce neurotransmitter release onto auditory nerve fibres. Since immature IHCs express both alpha1D (Cav1.3) Ca2+ and Na+ currents that activate near the resting potential, we examined whether these two conductances are involved in shaping the action potentials. Both had extremely rapid activation kinetics, followed by fast and complete voltage-dependent inactivation for the Na+ current, and slower, partially Ca2+-dependent inactivation for the Ca2+ current. Only the Ca2+ current is necessary for spontaneous and induced action potentials, and 29 % of cells lacked a Na+ current. The Na+ current does, however, shorten the time to reach the action-potential threshold, whereas the Ca2+ current is mainly involved, together with the K+ currents, in determining the speed and size of the spikes. Both currents increased in size up to the end of the first postnatal week. After this, the Ca2+ current reduced to about 30 % of its maximum size and persisted in mature IHCs. The Na+ current was downregulated around the onset of hearing, when the spiking is also known to disappear. Although the Na+ current was observed as early as embryonic day 16.5, its role in action-potential generation was only evident from just after birth, when the resting membrane potential became sufficiently negative to remove a sizeable fraction of the inactivation (half inactivation was at -71 mV). The size of both currents was positively correlated with the developmental change in action-potential frequency.

  20. Action potentials reliably invade axonal arbors of rat neocortical neurons

    OpenAIRE

    Cox, Charles L.; Denk, Winfried; Tank, David W.; Svoboda, Karel

    2000-01-01

    Neocortical pyramidal neurons have extensive axonal arborizations that make thousands of synapses. Action potentials can invade these arbors and cause calcium influx that is required for neurotransmitter release and excitation of postsynaptic targets. Thus, the regulation of action potential invasion in axonal branches might shape the spread of excitation in cortical neural networks. To measure the reliability and extent of action potential invasion into axonal arbors, we have used two-photon...

  1. Relationships between sensory "gating out" and sensory "gating in" of auditory evoked potentials in schizophrenia: a pilot study.

    Science.gov (United States)

    Gjini, Klevest; Arfken, Cynthia; Boutros, Nash N

    2010-08-01

    The interrelationship between the ability to inhibit incoming redundant input (gating out) and the ability of the brain to respond when the stimulus changes (gating in), has not been extensively examined. We administered a battery of auditory evoked potential tests to a group of chronic, medicated schizophrenia patients (N=12) and a group of healthy subjects (N=12) in order to examine relationships between "gating out" measures (suppression with repetition of the P50, N100, and P200 evoked responses), and the mismatch negativity (MMN) and the P300 event related potentials as measures of "gating in". Gating ratios for N100 and P200 in a visual attention paired-click task differed significantly between groups. Mismatch negativity and P300 potential amplitudes were also significantly reduced in the patient group. When including all subjects (N=24) a negative correlation was found between the P50 gating and the amplitude of the MMN. In healthy subjects this correlation was significantly stronger compared to schizophrenia patients. While no significant correlation was noted between the amplitudes of the P300 and any gating measures when all 24 subjects were included, a significant negative correlation was seen between the P200 gating and the P300 amplitudes in schizophrenia patients; an opposite trend was noted in healthy subjects. Finally, a positive correlation was seen between the P300 and MMN (to abstract deviance) amplitudes in healthy subjects, but the opposite was found in patients. These results suggest that further study of these interrelationships could inform the understanding of information processing abnormalities in schizophrenia.

  2. THE EFFECTS OF SALICYLATE ON AUDITORY EVOKED POTENTIAL AMPLITWDE FROM THE AUDITORY CORTEX AND AUDITORY BRAINSTEM

    Institute of Scientific and Technical Information of China (English)

    Brian Sawka; SUN Wei

    2014-01-01

    Tinnitus has often been studied using salicylate in animal models as they are capable of inducing tempo-rary hearing loss and tinnitus. Studies have recently observed enhancement of auditory evoked responses of the auditory cortex (AC) post salicylate treatment which is also shown to be related to tinnitus like behavior in rats. The aim of this study was to observe if enhancements of the AC post salicylate treatment are also present at structures in the brainstem. Four male Sprague Dawley rats with AC implanted electrodes were tested for both AC and auditory brainstem response (ABR) recordings pre and post 250 mg/kg intraperitone-al injections of salicylate. The responses were recorded as the peak to trough amplitudes of P1-N1 (AC), ABR wave V, and ABR waveⅡ. AC responses resulted in statistically significant enhancement of ampli-tude at 2 hours post salicylate with 90 dB stimuli tone bursts of 4, 8, 12, and 20 kHz. Wave V of ABR re-sponses at 90 dB resulted in a statistically significant reduction of amplitude 2 hours post salicylate and a mean decrease of amplitude of 31%for 16 kHz. WaveⅡamplitudes at 2 hours post treatment were signifi-cantly reduced for 4, 12, and 20 kHz stimuli at 90 dB SPL. Our results suggest that the enhancement chang-es of the AC related to salicylate induced tinnitus are generated superior to the level of the inferior colliculus and may originate in the AC.

  3. Electric stimulation at sciatic nerve evokes long-term potentiation of cornu dorsale medullae spinalis field potential in rats at various developmental phases

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    BACKGROUND: Long-term potentiation of cornu dorsale medullae spinalis field potential in adult rats has already been reported; however, there is lack of correlated researches on naenonate, infant and adult rats which have different responses to pain conduction information.OBJECTIVE: To observe the various effects of electric stimulation at sciatic nerve on long-term potentiation of evoked field potential at superficial layer of cornu dorsale medullae spinalis of rats at various developmental phases and analyze manifestations of pain conduction information at superficial layers ( Ⅰ - Ⅱ)of cornu dorsale medullae spinalis in immature rats.DESIGN: Grouping controlled study.SETTING: Department of Physiology, Medical College of Wuhan University.MATERIALS: The experiment was carried out in the Laboratory of Physiology (provincial laboratory),Medical College of Wuhan University from March 2006 to May 2007. A total of 27 healthy male Sprague-Dawley (SD) rats, 17- 90 days old, SPF grade, weighing 41 -200 g, were provided by Experimental Animal Center, Medical College of Wuhan University.METHODS: Based on their birthdays, rats were divided into naenonate group (17 - 20 days old, weighing 41-52 g, n =10), infant group (35 - 50 days old, weighing 87 - 125 g, n =10) and adult group (60 - 90 days old, weighing 180 -200 g, n =7). Left sciatic nerve was separated and stimulated with single square wave (15 V, 0.5 ms). Meanwhile, evoked field potential was recorded at superficial layers of lateral T13 - L1 cornu dorsale medullae spinalis and then stimulated with high-frequent and high-intensive tetanizing current (30 -40 V, 0.5 ms, 100 Hz, 1 s per bundle, 10 s in bundle interval) four times. After the operation, onset of long-term potentiation was observed; meanwhile, amplitude changes and latency of field potential were analyzed.MAIN OUTCOME MEASURES: Amplitude and latency changes of field potential at superficial layers of cornu dorsale medullae spinalis of rats in the three

  4. Visual Evoked Potentials to Light Flashes in Captive Rhesus Monkeys: A Study Reflecting Cerebral Cortical Activity and Brain Maturation

    Directory of Open Access Journals (Sweden)

    S.A. Solís-Chávez

    2014-01-01

    Full Text Available Visual evoked potentials (VEPs are useful electrophysiological diagnostic tools for evaluating retinal response of the visual cortex and detecting its functional integrity in humans and animals. To analyze the VEPs and physiologic response of the visual pathway of a random population of captive-bred monkeys of the Macaca mulatta species throughout different physiologic stages after stimulation with stroboscopic light flashes. In this study we used 20 non-human primates (M. mulatta, 10 males and 10 females, divided into five age-dependant cohorts of 2 males and 2 females. Two replicable negative waveforms and one positive were recorded, as reliable indicators of electrical conductivity at specific anatomical nuclei of the visual pathways. Statistically significant differences were primarily observed in group 1 when compared against the remaining groups for the three evaluated waveforms. Waveform morphology characteristically presented steady deviations related to ontogenetic development of the studied population.

  5. Comparison of clinical, magnetic resonance and evoked potentials data in a case of valproic-acid-related hyperammonemic coma

    Energy Technology Data Exchange (ETDEWEB)

    Hantson, Philippe [Universite Catholique de Louvain, Department of Intensive Care, Cliniques Saint-Luc, Brussels (Belgium); Grandin, Cecile; Duprez, Thierry [Universite Catholique de Louvain, Department of Neuroradiology, Cliniques Saint-Luc, Brussels (Belgium); Nassogne, Marie-Cecile [Universite Catholique de Louvain, Department of Pediatric Neurology, Cliniques Saint-Luc, Brussels (Belgium); Guerit, Jean-Michel [Universite Catholique de Louvain, Laboratory of Neurophysiology, Cliniques Saint-Luc, Brussels (Belgium)

    2005-01-01

    Magnetic resonance (MR) multimodality evoked potentials (MEPs) and clinical findings were correlated in a 47-year-old epileptic man in whom parenteral valproic acid (VPA) therapy induced severe comatose hyperammonemic encephalopathy without biological signs of hepatotoxicity (or hepatocytic dysfunction). Although the plasma VPA level remained within a normal therapeutic range, the ammoniemia increased to a toxic peak level at 411 {mu}mol/l 24 h after symptom onset, requiring VPA therapy discontinuation. Brain MR monitoring demonstrated early cytotoxic edema evolving into delayed vasogenic edema and final brain atrophy. Concomitantly to abnormalities within the brainstem on MR images, an increase in brainstem conduction at MEPs and clinical disturbance of brainstem reflexes were observed at the initial phase of the disease course. Later, the resolution of the MR and MEPs abnormalities paralleled the clinical recovery of the reflexes. (orig.)

  6. Pure phase-locking of beta/gamma oscillation contributes to the N30 frontal component of somatosensory evoked potentials

    Directory of Open Access Journals (Sweden)

    Leroy Axelle

    2007-09-01

    Full Text Available Abstract Background Evoked potentials have been proposed to result from phase-locking of electroencephalographic (EEG activities within specific frequency bands. However, the respective contribution of phasic activity and phase resetting of ongoing EEG oscillation remains largely debated. We here applied the EEGlab procedure in order to quantify the contribution of electroencephalographic oscillation in the generation of the frontal N30 component of the somatosensory evoked potentials (SEP triggered by median nerve electrical stimulation at the wrist. Power spectrum and intertrial coherence analysis were performed on EEG recordings in relation to median nerve stimulation. Results The frontal N30 component was accompanied by a significant phase-locking of beta/gamma oscillation (25–35 Hz and to a lesser extent of 80 Hz oscillation. After the selection in each subject of the trials for which the power spectrum amplitude remained unchanged, we found pure phase-locking of beta/gamma oscillation (25–35 Hz peaking about 30 ms after the stimulation. Transition across trials from uniform to normal phase distribution revealed temporal phase reorganization of ongoing 30 Hz EEG oscillations in relation to stimulation. In a proportion of trials, this phase-locking was accompanied by a spectral power increase peaking in the 30 Hz frequency band. This corresponds to the complex situation of 'phase-locking with enhancement' in which the distinction between the contribution of phasic neural event versus EEG phase resetting is hazardous. Conclusion The identification of a pure phase-locking in a large proportion of the SEP trials reinforces the contribution of the oscillatory model for the physiological correlates of the frontal N30. This may imply that ongoing EEG rhythms, such as beta/gamma oscillation, are involved in somatosensory information processing.

  7. Conduction velocity of antigravity muscle action potentials.

    Science.gov (United States)

    Christova, L; Kosarov, D; Christova, P

    1992-01-01

    The conduction velocity of the impulses along the muscle fibers is one of the parameters of the extraterritorial potentials of the motor units allowing for the evaluation of the functional state of the muscles. There are no data about the conduction velocities of antigravity muscleaction potentials. In this paper we offer a method for measuring conduction velocity of potentials of single MUs and the averaged potentials of the interference electromiogram (IEMG) lead-off by surface electrodes from mm. sternocleidomastoideus, trapezius, deltoideus (caput laterale) and vastus medialis. The measured mean values of the conduction velocity of antigravity muscles potentials can be used for testing the functional state of the muscles.

  8. Steady-state evoked potentials to study the processing of tactile and nociceptive somatosensory input in the human brain.

    Science.gov (United States)

    Colon, E; Legrain, V; Mouraux, A

    2012-10-01

    The periodic presentation of a sensory stimulus induces, at certain frequencies of stimulation, a sustained electroencephalographic response of corresponding frequency, known as steady-state evoked potentials (SS-EP). In visual, auditory and vibrotactile modalities, studies have shown that SS-EP reflect mainly activity originating from early, modality-specific sensory cortices. Furthermore, it has been shown that SS-EP have several advantages over the recording of transient event-related brain potentials (ERP), such as a high signal-to-noise ratio, a shorter time to obtain reliable signals, and the capacity to frequency-tag the cortical activity elicited by concurrently presented sensory stimuli. Recently, we showed that SS-EP can be elicited by the selective activation of skin nociceptors and that nociceptive SS-EP reflect the activity of a population of neurons that is spatially distinct from the somatotopically-organized population of neurons underlying vibrotactile SS-EP. Hence, the recording of SS-EP offers a unique opportunity to study the cortical representation of nociception and touch in humans, and to explore their potential crossmodal interactions. Here, (1) we review available methods to achieve the rapid periodic stimulation of somatosensory afferents required to elicit SS-EP, (2) review previous studies that have characterized vibrotactile and nociceptive SS-EP, (3) discuss the nature of the recorded signals and their relationship with transient event-related potentials and (4) outline future perspectives and potential clinical applications of this technique.

  9. The n10 component of the ocular vestibular-evoked myogenic potential (oVEMP) is distinct from the R1 component of the blink reflex

    NARCIS (Netherlands)

    Smulders, Y. E.; Welgampola, M. S.; Burgess, A. M.; McGarvie, L. A.; Halmagyi, G. M.; Curthoys, I. S.

    2009-01-01

    Objective: Bone-conducted vibration (BCV) in the midline at the hairline (Fz), results in short latency potentials recorded by surface electrodes beneath the eyes - the ocular vestibular-evoked myogenic potential (oVEMP). The early negative component of the oVEMP, n10, is due to vestibular stimulati

  10. Intraoperative monitoring during decompression of the spinal cord and spinal nerves using transcranial motor-evoked potentials: The law of twenty percent.

    Science.gov (United States)

    Tanaka, Satoshi; Hirao, Jun; Oka, Hidehiro; Akimoto, Jiro; Takanashi, Junko; Yamada, Junichi

    2015-09-01

    Motor-evoked potential (MEP) monitoring was performed during 196 consecutive spinal (79 cervical and 117 lumbar) surgeries for the decompression of compressive spinal and spinal nerve diseases. MEP monitoring in spinal surgery has been considered sensitive to predict postoperative neurological recovery. In this series, transcranial stimulation consisted of trains of five pulses at a constant voltage (200-600 V). For the normalization of MEP, we recorded compound muscle action potentials (CMAP) after peripheral nerve stimulation, usually on the median nerve at the wrist 2 seconds before or after each transcranial stimulation of the motor area, for all operations. The sensitivity and specificity of MEP monitoring was 100% and 97.4%, respectively, or 96.9% with or without CMAP compensation (if the threshold of postoperative motor palsy was defined as 20% relative amplitude rate [RAR]). The mean RAR after CMAP normalization, of the most affected muscle in the patient group with excellent postoperative results (recovery rate of a Japan Orthopedic Association score of more than 50%) was significantly higher than that in the other groups (p=0.0224). All patients with an amplitude increase rate (AIR) with CMAP normalization of more than 20% achieved neurological recovery postoperatively. Our results suggest that if the RAR is more than 20%, postoperative motor palsy can be avoided in spinal surgery. If the AIR with normalization by CMAP after peripheral nerve stimulation is more than 20%, neurological recovery can be expected in spinal surgery. PMID:26142049

  11. Comparison of auditory evoked potentials and the A-line ARX Index for monitoring the hypnotic level during sevoflurane and propofol induction

    DEFF Research Database (Denmark)

    Litvan, H; Jensen, E W; Revuelta, M;

    2002-01-01

    Extraction of the middle latency auditory evoked potentials (AEP) by an auto regressive model with exogenous input (ARX) enables extraction of the AEP within 1.7 s. In this way, the depth of hypnosis can be monitored at almost real-time. However, the identification and the interpretation of the a......Extraction of the middle latency auditory evoked potentials (AEP) by an auto regressive model with exogenous input (ARX) enables extraction of the AEP within 1.7 s. In this way, the depth of hypnosis can be monitored at almost real-time. However, the identification and the interpretation...

  12. Comparison of conventional averaged and rapid averaged, autoregressive-based extracted auditory evoked potentials for monitoring the hypnotic level during propofol induction

    DEFF Research Database (Denmark)

    Litvan, Héctor; Jensen, Erik W; Galan, Josefina;

    2002-01-01

    The extraction of the middle latency auditory evoked potentials (MLAEP) is usually done by moving time averaging (MTA) over many sweeps (often 250-1,000), which could produce a delay of more than 1 min. This problem was addressed by applying an autoregressive model with exogenous input (ARX) that...... enables extraction of the auditory evoked potentials (AEP) within 15 sweeps. The objective of this study was to show that an AEP could be extracted faster by ARX than by MTA and with the same reliability....

  13. The effects of total and REM sleep deprivation on laser-evoked potential threshold and pain perception.

    Science.gov (United States)

    Azevedo, Eduardo; Manzano, Gilberto M; Silva, Andressa; Martins, Raquel; Andersen, Monica L; Tufik, Sergio

    2011-09-01

    We investigated the effects of total and rapid eye movement (REM) sleep deprivation on the thermal nociceptive threshold and pain perception using the objective laser-evoked potential (LEP) and the subjective visual analogue scale (VAS). Twenty-eight male adult volunteers were assigned into Control (CTRL), Total (T-SD), and REM (REM-SD) Sleep Deprivation groups. The T-SD and REM-SD volunteers were totally or selectively deprived of sleep for 2 and 4 consecutive nights, respectively. Pain parameters were measured daily during the experimental period. Volunteers were stimulated on the back of the hand by blocks of 50 diode laser pulses. Intensities increased between successive blocks, ranging from nonnoxious to noxious levels, and the LEP threshold was identified based on the evoked-response onset. Both the LEP threshold and VAS ratings were significantly increased after the second night of T-SD. No significant variations were observed in the REM-SD group, suggesting a predominant role for slow wave sleep rather than selective REM-SD in pain perception. Also, for both sleep-deprived groups, the mean values of the LEP threshold and VAS ratings showed a gradual increase that was proportional to the SD deprivation time, followed by a decrease after 1 night of sleep restoration. These findings demonstrate a hyperalgesic modification to pain perception (as reflected by the augmented VAS) and a concomitant increase in the LEP threshold following T-SD, an apparently contradictory effect that can be explained by differences in the ways that attention affects these pain measurements.

  14. Effects of glutamate receptor agonists on the P13 auditory evoked potential and startle response in the rat

    Directory of Open Access Journals (Sweden)

    Christen eSimon

    2011-01-01

    Full Text Available The P13 potential is the rodent equivalent of the P50 potential, which is an evoked response recorded at the vertex (Vx 50 msec following an auditory stimulus in humans. Both the P13 and P50 potentials are only present during waking and rapid eye movement (REM sleep, and are considered to be measures of level of arousal. The source of the P13 and P50 potentials appears to be the pedunculopontine nucleus (PPN, a brainstem nucleus with indirect ascending projections to the cortex through the intralaminar thalamus (ILT, mediating arousal, and descending inhibitory projections to the caudal pontine reticular formation (CPRF, which mediates the auditory startle response (SR. We tested the hypothesis that intracranial microinjection (ICM of glutamate (GLU or GLU receptor agonists will increase the activity of PPN neurons, resulting in an increased P13 potential response, and decreased SR due to inhibitory projections from the PPN to the CPRF, in freely moving animals. Cannulae were inserted into the PPN to inject neuroactive agents, screws were inserted into the Vx in order to record the P13 potential, and electrodes inserted into the dorsal nuchal muscle to record electromyograms (EMGs and SR amplitude. Our results showed that ICM of GLU into the PPN dose-dependently increased the amplitude of the P13 potential and decreased the amplitude of the SR. Similarly, ICM of NMDA or KA into the PPN increased the amplitude of the P13 potential. These findings indicate that glutamatergic input to the PPN plays a role in arousal control in vivo, and changes in glutamatergic input, or excitability of PPN neurons, could be implicated in a number of neuropsychiatric disorders with the common symptoms of hyperarousal and REM sleep dysregulation.

  15. Analogue mouse pointer control via an online steady state visual evoked potential (SSVEP) brain-computer interface

    Science.gov (United States)

    Wilson, John J.; Palaniappan, Ramaswamy

    2011-04-01

    The steady state visual evoked protocol has recently become a popular paradigm in brain-computer interface (BCI) applications. Typically (regardless of function) these applications offer the user a binary selection of targets that perform correspondingly discrete actions. Such discrete control systems are appropriate for applications that are inherently isolated in nature, such as selecting numbers from a keypad to be dialled or letters from an alphabet to be spelled. However motivation exists for users to employ proportional control methods in intrinsically analogue tasks such as the movement of a mouse pointer. This paper introduces an online BCI in which control of a mouse pointer is directly proportional to a user's intent. Performance is measured over a series of pointer movement tasks and compared to the traditional discrete output approach. Analogue control allowed subjects to move the pointer faster to the cued target location compared to discrete output but suffers more undesired movements overall. Best performance is achieved when combining the threshold to movement of traditional discrete techniques with the range of movement offered by proportional control.

  16. Kappa opioid receptor activation potentiates the cocaine-induced increase in evoked dopamine release recorded in vivo in the mouse nucleus accumbens.

    Science.gov (United States)

    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

  17. Expectation to feel more pain disrupts the habituation of laser-pain rating and laser-evoked potential amplitudes.

    Science.gov (United States)

    Pazzaglia, Costanza; Testani, Elisa; Giordano, Rocco; Padua, Luca; Valeriani, Massimiliano

    2016-10-01

    Increased pain perception due to the expectation to feel more pain is called nocebo effect. The present study aimed at investigating whether: (1) the mere expectation to feel more pain after the administration of an inert drug can affect the laser-pain rating and the laser-evoked potential (LEP) amplitude, and (2) the learning potentiates the nocebo effect. Eighteen healthy volunteers were told that an inert cream, applied on the right hand, would increase the laser pain and LEP amplitude to right hand stimulation. They were randomly assigned to either "verbal session" or "conditioning session". In the "verbal session", LEPs to both right and left hand stimulation were recorded at the same intensity before (baseline) and after cream application. In the "conditioning session", after an initial cream application the laser stimulus intensity was increased surreptitiously to make the subjects believe that the treatment really increased the pain sensation. Then, the cream was reapplied, and LEPs were recorded at the same stimulus intensity as at the baseline. It was found that the verbal suggestion to feel more pain disrupted the physiological habituation of the laser-pain rating and LEP amplitude to treated (right) hand stimulation. Unlike previously demonstrated for the placebo effect, the learning did not potentiate the nocebo effect. PMID:27461877

  18. Light scattering changes follow evoked potentials from hippocampal Schaeffer collateral stimulation

    DEFF Research Database (Denmark)

    Rector, D M; Poe, G R; Kristensen, Morten Pilgaard;

    1997-01-01

    a complex population synaptic potential that lasted 100-200 ms depending on stimulus intensity and electrode position. Light scattering changes peaked 20 ms after stimuli and occurred simultaneously with population spikes. A long-lasting light scattering component peaked 100-500 ms after the stimulus......, concurrently with larger population postsynaptic potentials. Optical signals occurred over a time course similar to that for electrical signals and increased with larger stimulation amplitude to a maximum, then decreased with further increases in stimulation current. Camera images revealed a topographic...

  19. Visual Perception and Frontal Lobe in Intellectual Disabilities: A Study with Evoked Potentials and Neuropsychology

    Science.gov (United States)

    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. Chiasmal coefficient of flash and pattern visual evoked potentials for detection of chiasmal misrouting in albinism

    NARCIS (Netherlands)

    Pott, JWR; Jansonius, NM; Kooijman, AC

    2003-01-01

    The diagnosis of albinism can be confirmed by electrophysiological examination, when chiasmal misrouting can be demonstrated. The present study describes a quantitative analysis method for this purpose. A chiasmal coefficient (CC) was calculated by correlating the differential potential over left an

  1. [Individualised medicine - potentials and need for action].

    Science.gov (United States)

    Hüsing, Bärbel

    2010-01-01

    Individualised medicine aims to classify seemingly homogenous patient groups into smaller clinically relevant subgroups (stratification) in order to be able to treat them differently, thus contributing to the improvement of health care services, to the prevention of inappropriate treatments and to the reduction of adverse effects. This article summarises a report to the Office of Technology Assessment at the German Bundestag and points out the need for action for transferring individualised medicine from research to clinical application: significant incentives are required in order to prove the clinical validity of newly identified biomarkers of complex diseases. Sustainable business models for the joint development of new applications by research institutions, biotechnology companies, pharmaceuticals and medical devices companies are required. Instruments for transferring knowledge from bench to bedside (translational research) and the existing regulatory framework should be further developed in order to strike an appropriate balance between incentives for accelerating the transfer of innovative technology to the health care sector while, at the same time, ensuring patient safety, high quality and clinical utility. PMID:21147435

  2. Brain potentials evoked by intraepidermal electrical stimuli reflect the central sensitization of nociceptive pathways

    OpenAIRE

    Liang, M.; Lee, M. C.; O'Neill, J.; Dickenson, A.H.; Iannetti, G.D.

    2016-01-01

    Central sensitization (CS), the increased sensitivity of the central nervous system to somatosensory inputs, accounts for secondary hyperalgesia, a typical sign of several painful clinical conditions. Brain potentials elicited by mechanical punctate stimulation using flat-tip probes can provide neural correlates of CS, but their signal-to-noise ratio is limited by poor synchronisation of the afferent nociceptive input. Additionally, mechanical punctate stimulation does not activate nociceptor...

  3. Study of the correlation of brainstem auditory evoked potentials and magnetic resonance imaging in children with spastic cerebral palsy

    Energy Technology Data Exchange (ETDEWEB)

    Fobe, Lisete Pessoa de Oliveira [Sao Paulo Univ., SP (Brazil). Faculdade de Medicina]. E-mail: lispessoa@yahoo.com

    1999-12-01

    Central auditory evaluation in 21 children with cerebral palsy was done with brainstem auditory evoked potentials (BAEP) and correlated with brain magnetic resonance imaging findings (MRI); 12 boys and 9 girls between 5 and 12 years old were studied. All children had follow-up at the Institute of Orthopedics and Traumatology of Hospital das Clinicas da Faculdade de Medicina da Universidade de Sao Paulo. The control group was done with 17 children, 10 boys and 7 girls (mean age 8.06 years, SD 2.27 years). The BAEP abnormalities were: decrease of latency of wave V; decrease of latency III-V and I-IV intervals at the right side. All patients has MRI supratentorial abnormalities and 11 had brainstem atrophy. The MRI pathologic findings were: ventricular enlargement (n=17 or 80.95%), cortical/subcortical atrophy (n=15 or 71.42%), left brainstem atrophy (n=11 or 52.38%), periventricular leukomalacia (n=10 or 47.61%), infarction in the left middle cerebral artery territory (n=6 or 28.57%), and malformations such as schizencephaly and colpocephaly (n=5 or 23.80%). The findings of the decrease latencies in children with cerebral palsy suggest the contribution of decussating auditory fibers at the lower and upper pons and midbrain, the lack of homogeneity of the surrounding volume of the conductor fibres and the presence of several concurrently active potential generators sources, should be facilitating mechanisms for the nervous input to brainstem. (author)

  4. Study of the correlation of brainstem auditory evoked potentials and magnetic resonance imaging in children with spastic cerebral palsy

    International Nuclear Information System (INIS)

    Central auditory evaluation in 21 children with cerebral palsy was done with brainstem auditory evoked potentials (BAEP) and correlated with brain magnetic resonance imaging findings (MRI); 12 boys and 9 girls between 5 and 12 years old were studied. All children had follow-up at the Institute of Orthopedics and Traumatology of Hospital das Clinicas da Faculdade de Medicina da Universidade de Sao Paulo. The control group was done with 17 children, 10 boys and 7 girls (mean age 8.06 years, SD 2.27 years). The BAEP abnormalities were: decrease of latency of wave V; decrease of latency III-V and I-IV intervals at the right side. All patients has MRI supratentorial abnormalities and 11 had brainstem atrophy. The MRI pathologic findings were: ventricular enlargement (n=17 or 80.95%), cortical/subcortical atrophy (n=15 or 71.42%), left brainstem atrophy (n=11 or 52.38%), periventricular leukomalacia (n=10 or 47.61%), infarction in the left middle cerebral artery territory (n=6 or 28.57%), and malformations such as schizencephaly and colpocephaly (n=5 or 23.80%). The findings of the decrease latencies in children with cerebral palsy suggest the contribution of decussating auditory fibers at the lower and upper pons and midbrain, the lack of homogeneity of the surrounding volume of the conductor fibres and the presence of several concurrently active potential generators sources, should be facilitating mechanisms for the nervous input to brainstem. (author)

  5. Loss of visual evoked potential following temporary occlusion of the superior hypophyseal artery during aneurysm clip placement surgery. Case report.

    Science.gov (United States)

    Goto, Tetsuya; Tanaka, Yuichiro; Kodama, Kunihiko; Kusano, Yoshikazu; Sakai, Keiichi; Hongo, Kazuhiro

    2007-10-01

    The authors report a case in which a 62-year-old woman with a history of subarachnoid hemorrhage due to a ruptured aneurysm was found to have a de novo paraclinoid aneurysm in the right internal carotid artery during a routine medical examination. Surgical clip placement was performed via a contralateral pterional approach under visual evoked potential (VEP) monitoring. The superior hypophyseal artery (SHA) was found to originate from the aneurysm body. The artery was temporarily occluded prior to application of the clip to the aneurysm neck. The VEP signal was lost 3 minutes after the SHA was occluded, and the potentials gradually recovered 10 minutes after the artery was released. The disappearance of VEP signal was reproducible with SHA occlusion. The clip was applied to the aneurysm body to preserve the origin of the SHA. The patient did not have any deterioration of vision after surgery. Intraoperative VEP monitoring can be used to help determine whether the SHA can be sacrificed safely.

  6. Pressure-induced basilar membrane position shifts and the stimulus-evoked potentials in the low-frequency region of the guinea pig cochlea

    NARCIS (Netherlands)

    Fridberger, A; vanMaarseveen, JTPW; Scarfone, E; Ulfendahl, M; Flock, B; Flock, A

    1997-01-01

    We have used the guinea pig isolated temporal bone preparation to investigate changes in the nonlinear properties of the tone-evoked cochlear potentials during reversible step displacements of the basilar membrane towards either the scala tympani or the scala vestibuli. The position shifts were prod

  7. DEPRESSION OF THE PHOTIC AFTER DISCHARGE OF FLASH EVOKED POTENTIALS BY PHYSOSTIGMINE, CARBARYL AND PROPOXUR AND THE RELATIONSHIP TO INHIBITION OF BRAIN CHOLINESTERASE

    Science.gov (United States)

    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...

  8. Comparison of conventional averaged and rapid averaged, autoregressive-based extracted auditory evoked potentials for monitoring the hypnotic level during propofol induction

    DEFF Research Database (Denmark)

    Litvan, Héctor; Jensen, Erik W; Galan, Josefina;

    2002-01-01

    The extraction of the middle latency auditory evoked potentials (MLAEP) is usually done by moving time averaging (MTA) over many sweeps (often 250-1,000), which could produce a delay of more than 1 min. This problem was addressed by applying an autoregressive model with exogenous input (ARX) that...

  9. Comparison of auditory evoked potentials and the A-line ARX Index for monitoring the hypnotic level during sevoflurane and propofol induction

    DEFF Research Database (Denmark)

    Litvan, H; Jensen, E W; Revuelta, M;

    2002-01-01

    Extraction of the middle latency auditory evoked potentials (AEP) by an auto regressive model with exogenous input (ARX) enables extraction of the AEP within 1.7 s. In this way, the depth of hypnosis can be monitored at almost real-time. However, the identification and the interpretation of the a...

  10. Changes in visual evoked potential of children with amblyopia%弱视儿童视觉诱发电位改变

    Institute of Scientific and Technical Information of China (English)

    赵冬卉; 夏娟; 洪流

    2002-01-01

    @@ Amblyopia is common among children.Visual evoked potential(VEP) is a new approach for diagnosis and evaluation of amblyopia. VEP was examined using tessellation stimulation in our hospital since 1999.20 healthy children were selected as controls.Here is the report.

  11. Angle-action estimation in a general axisymmetric potential

    OpenAIRE

    Sanders, Jason

    2012-01-01

    The usefulness of angle-action variables in galaxy dynamics is well known, but their use is limited due to the difficulty of their calculation in realistic galaxy potentials. Here we present a method for estimating angle-action variables in a realistic Milky Way axisymmetric potential by locally fitting a St\\"ackel potential over the region an orbit probes. The quality of the method is assessed by comparison with other known methods for estimating angle-action variables of a range of disc and...

  12. Conduction velocity of the human spinothalamic tract as assessed by laser evoked potentials

    DEFF Research Database (Denmark)

    Cruccu, G.; Iannetti, G. D.; Agostino, R.;

    2000-01-01

    stimuli yielded large-amplitude vertex potentials consisting of a negative wave at a peak latency of about 200 ms followed by a positive wave at a peak latency of about 300 ms. The mean conduction velocity of the STT was 21 m/s, i.e. higher than the reported velocity of the corresponding primary sensory...... neurons (type II AMH). Because dorsal stimulation readily yields reproducible brain LEPs, we expect this technique to be useful as a diagnostic tool for assessing the level of spinal cord lesions. NeuroReport 11:3029-3032 (C) 2000 Lippincott Williams & Wilkins....

  13. Single trial somatosensory evoked potential extraction with ARX filtering for a combined spinal cord intraoperative neuromonitoring technique

    Directory of Open Access Journals (Sweden)

    Merzagora Anna

    2007-01-01

    Full Text Available Abstract Background When spinal cord functional integrity is at risk during surgery, intraoperative neuromonitoring is recommended. Tibial Single Trial Somatosensory Evoked Potentials (SEPs and H-reflex are here used in a combined neuromonitoring method: both signals monitor the spinal cord status, though involving different nervous pathways. However, SEPs express a trial-to-trial variability that is difficult to track because of the intrinsic low signal-to-noise ratio. For this reason single trial techniques are needed to extract SEPs from the background EEG. Methods The analysis is performed off line on data recorded in eight scoliosis surgery sessions during which the spinal cord was simultaneously monitored through classical SEPs and H-reflex responses elicited by the same tibial nerve electrical stimulation. The single trial extraction of SEPs from the background EEG is here performed through AutoRegressive filter with eXogenous input (ARX. The electroencephalographic recording can be modeled as the sum of the background EEG, which can be described as an autoregressive process not related to the stimulus, and the evoked potential (EP, which can be viewed as a filtered version of a reference signal related to the stimulus. The choice of the filter optimal orders is based on the Akaike Information Criterion (AIC. The reference signal used as exogenous input in the ARX model is a weighted average of the previous SEPs trials with exponential forgetting behavior. Results The moving average exponentially weighted, used as reference signal for the ARX model, shows a better sensibility than the standard moving average in tracking SEPs fast inter-trial changes. The ability to promptly detect changes allows highlighting relations between waveform changes and surgical maneuvers. It also allows a comparative study with H-reflex trends: in particular, the two signals show different fall and recovery dynamics following stressful conditions for the spinal

  14. Investigation of potential artefactual changes in measurements of impedance changes during evoked activity: implications to electrical impedance tomography of brain function.

    Science.gov (United States)

    Aristovich, Kirill Y; Dos Santos, Gustavo S; Holder, David S

    2015-06-01

    Electrical impedance tomography (EIT) could provide images of fast neural activity in the adult human brain with a resolution of 1 ms and 1 mm by imaging impedance changes which occur as ion channels open during neuronal depolarization. The largest changes occur at dc and decrease rapidly over 100 Hz. Evoked potentials occur in this bandwidth and may cause artefactual apparent impedance changes if altered by the impedance measuring current. These were characterized during the compound action potential in the walking leg nerves of Cancer pagurus, placed on Ag/AgCl hook electrodes, to identify how to avoid artefactual changes during brain EIT. Artefact-free impedance changes (δZ) decreased with frequency from -0.045 ± 0.01% at 225 Hz to -0.02 ± 0.01% at 1025 Hz (mean ± 1 SD, n = 24 in 12 nerves) which matched changes predicted by a finite element model. Artefactual δZ reached c.300% and 50% of the genuine membrane impedance change at 225 Hz and 600 Hz respectively but decreased with frequency of the applied current and was negligible above 1 kHz. The proportional amplitude (δZ (%)) of the artefact did not vary significantly with the amplitude of injected current of 5-20 µA pp. but decreased significantly from -0.09 ± 0.024 to -0.03 ± 0.023% with phase of 0 to 45°. For fast neural EIT of evoked activity in the brain, artefacts may arise with applied current of >10 µA. Independence of δZ with respect to phase but not the amplitude of applied current controls for them; they can be minimized by randomizing the phase of the applied measuring current and excluded by recording at >1 kHz. PMID:26009486

  15. Reduced habituation of auditory evoked potentials indicate cortical hyper-excitability in Fragile X Syndrome.

    Science.gov (United States)

    Ethridge, L E; White, S P; Mosconi, M W; Wang, J; Byerly, M J; Sweeney, J A

    2016-01-01

    Sensory hypersensitivities are common, clinically distressing features of Fragile X Syndrome (FXS). Preclinical evidence suggests this abnormality may result from synaptic hyper-excitability in sensory systems. This model predicts reduced sensory habituation to repeated stimulus presentation. Fourteen adolescents and adults with FXS and 15 age-matched controls participated in a modified auditory gating task using trains of 4 identical tones during dense array electroencephalography (EEG). Event-related potential and single trial time-frequency analyses revealed decreased habituation of the N1 event-related potential response in FXS, and increased gamma power coupled with decreases in gamma phase-locking during the early-stimulus registration period. EEG abnormalities in FXS were associated with parent reports of heightened sensory sensitivities and social communication deficits. Reduced habituation and altered gamma power and phase-locking to auditory cues demonstrated here in FXS patients parallels preclinical findings with Fmr1 KO mice. Thus, the EEG abnormalities seen in FXS patients support the model of neocortical hyper-excitability in FXS, and may provide useful translational biomarkers for evaluating novel treatment strategies targeting its neural substrate. PMID:27093069

  16. Scalp-recorded oscillatory potentials evoked by transient pattern-reversal visual stimulation in man.

    Science.gov (United States)

    Sannita, W G; Lopez, L; Piras, C; Di Bon, G

    1995-05-01

    Replicable oscillatory potentials, time-locked to pattern stimuli (9.0 degrees central; counterphase reversal at 2.13 Hz) were dissociated from conventional, broad-band VEPs recorded in healthy volunteers at occipital scalp locations by high-pass digital filtering at 17.0-20.0 Hz. Nine consecutive wavelets were identified with a 56.4 +/- 8.4 msec mean latency of the first replicable wavelet and mean peak-to-peak amplitude varying between 0.9 and 2.0 muV. The first 2 wavelets had significantly shorter latencies than wave N70 of unfiltered VEP, whereas the last 2 wavelets had longer latencies than N145. Latency and amplitude values varied as a function of contrast and spatial frequency of the stimulus, with shorter latencies and larger amplitudes at 60-90% contrast level and tuning of amplitude at 5.0 c/deg. All wavelets were correlated with wave P100 of unfiltered VEP, while a correlation with N70 of VEP was observed only for those wavelets with latencies in the range of wave P100. Two patients with documented brain lesions involving the visual system are described as examples of oscillatory responses occurring irrespective of filter bandpass and instead of the expected conventional VEP when the generation of these is interfered with by brain pathology. A substantial cortical contribution to the origin of the oscillatory response is conceivable. It is suggested that the oscillatory response to pattern-reversal stimulation reflects events in the visual system that are parallel to, and partly independent of, the conventional VEP, with potential application in research or for clinical purposes. PMID:7750446

  17. Radial propagation of muscle action potential along the tubular system examined by potential-sensitive dyes

    OpenAIRE

    Nakajima, S.; Gilai, A.

    1980-01-01

    Isolated single (Xenopus) muscle fibers were stained with a non-permeant potential-probing dye, merocyanine rhodanine (WW375) or merocyanine oxazolone (NK2367). When the fiber was massively stimulated, an absorption change (wave a), which seemed to reflect the action potential, occurred. Simultaneous recording of optical changes and intracellular action potentials revealed that the time-course of wave a was slower than the action potential: the peak of wave a was attained at 1 ms, and the pea...

  18. Disappearance of click-evoked potentials on the neck of the guinea pig by pharmacological and surgical destruction of the peripheral vestibular afferent system.

    Science.gov (United States)

    Matsuzaki, Masaki; Murofushi, Toshihisa

    2003-10-01

    In order to establish an animal model of acoustically evoked vestibulo-collic reflex, the so-called vestibular evoked myogenic potential in humans, potentials evoked by loud clicks on the neck of the guinea pig were recorded using subjects whose peripheral vestibular endorgans or vestibular afferents had been damaged. Four normal control guinea pigs, four guinea pigs that received an intramuscular injection of gentamicin for 20 days (90 mg/kg/day) and five guinea pigs whose vestibular nerves were surgically sectioned were used in this study. Under general anesthesia with an intraperitoneal injection of pentobarbital sodium (40 mg/kg), auditory brainstem responses (ABRs) were recorded. Then, potentials evoked by loud clicks on the pre-vertebral muscle at the level of the third cervical vertebral bone were recorded using silver ball electrodes. As a result, a distinctive negative peak (NP) with a latency of 6-8 ms was recorded in all animals in the control group. NP was not observed in the gentamicin-administered group while ABR was preserved. After sectioning the vestibular nerve, NP was abolished while ABR was preserved. From these results, NP could be of vestibular origin. These results are in agreement with a previous report of NP using subjects whose cochlea had been damaged pharmacologically.

  19. Evoked related potentials correlates of empathy for pain from adolescence through adulthood

    Directory of Open Access Journals (Sweden)

    Nathalie eMella

    2012-11-01

    Full Text Available Affective and cognitive empathy are traditionally differentiated, the affective component being concerned with resonating with another’s emotional state, whereas the cognitive component reflects regulation of the resulting distress and understanding of another’s mental states (see Decety and Jackson, 2004 for a review. Adolescence is a critical period for the development of cognitive control processes necessary to regulate affective processes: it is only in young adulthood that these control processes achieve maturity (Steinberg, 2005. Thus, one should expect adolescents to show greater automatic empathy than young adults. The present study aimed at exploring the neural correlates of affective (automatic and cognitive empathy for pain from adolescence to young adulthood. With this aim, Event Related Potentials (ERPs were recorded in 32 participants (aged 11 to 39 in a task designed to dissociate these components. ERPs results showed an early automatic frontocentral response to pain (that was not modulated by task demand and a late parietal response to painful stimuli modulated by attention to pain cues. Adolescents exhibited earlier automatic responses to painful situations than young adults did and showed greater activity in the late cognitive component even when viewing neutral stimuli. Results are discussed in the context of the development of regulatory abilities during adolescence.

  20. Time-course of trigeminal versus olfactory stimulation: evidence from chemosensory evoked potentials.

    Science.gov (United States)

    Flohr, Elena L R; Boesveldt, Sanne; Haehner, Antje; Iannilli, Emilia; Sinding, Charlotte; Hummel, Thomas

    2015-03-01

    Habituation of responses to chemosensory signals has been explored in many ways. Strong habituation and adaptation processes can be observed at the various levels of processing. For example, with repeated exposure, amplitudes of chemosensory event-related potentials (ERP) decrease over time. However, long-term habituation has not been investigated so far and investigations of differences in habituation between trigeminal and olfactory ERPs are very rare. The present study investigated habituation over a period of approximately 80 min for two olfactory and one trigeminal stimulus, respectively. Habituation was examined analyzing the N1 and P2 amplitudes and latencies of chemosensory ERPs and intensity ratings. It was shown that amplitudes of both components - and intensity ratings - decreased from the first to the last block. Concerning ERP latencies no effects of habituation were seen. Amplitudes of trigeminal ERPs diminished faster than amplitudes of olfactory ERPs, indicating that the habituation of trigeminal ERPs is stronger than habituation of olfactory ERPs. Amplitudes of trigeminal ERPs were generally higher than amplitudes of olfactory ERPs, as it has been shown in various studies before. The results reflect relatively selective central changes in response to chemosensory stimuli over time.

  1. Changes in somatosensory-evoked potentials and high-frequency oscillations after paired-associative stimulation.

    Science.gov (United States)

    Murakami, Takenobu; Sakuma, Kenji; Nomura, Takashi; Uemura, Yusuke; Hashimoto, Isao; Nakashima, Kenji

    2008-01-01

    Paired-associative stimulation (PAS), combining electrical median nerve stimulation with transcranial magnetic stimulation (TMS) with a variable delay, causes long-term potentiation or depression (LTP/LTD)-like cortical plasticity. In the present study, we examined how PAS over the motor cortex affected a distant site, the somatosensory cortex. Furthermore, the influences of PAS on high-frequency oscillations (HFOs) were investigated to clarify the origin of HFOs. Interstimulus intervals between median nerve stimulation and TMS were 25 ms (PAS(25)) and 10 ms (PAS(10)). PAS was performed over the motor and somatosensory cortices. SEPs following median nerve stimulation were recorded before and after PAS. HFOs were isolated by 400-800 Hz band-pass filtering. PAS(25) over the motor cortex increased the N20-P25 and P25-N33 amplitudes and the HFOs significantly. The enhancement of the P25-N33 amplitude and the late HFOs lasted more than 60 min. After PAS(10) over the motor cortex, the N20-P25 and P25-N33 amplitudes decreased for 40 min, and the HFOs decreased for 60 min. Frontal SEPs were not affected after PAS over the motor cortex. PAS(25/10) over the somatosensory cortex did not affect SEPs and HFOs. PAS(25/10) over the motor cortex caused the LTP/LTD-like phenomena in a distant site, the somatosensory cortex. The PAS paradigms over the motor cortex can modify both the neural generators of SEPs and HFOs. HFOs may reflect the activation of GABAergic inhibitory interneurons regulating pyramidal neurons in the somatosensory cortex. PMID:17724581

  2. Comparison of Vestibular Evoked Myogenic Potential and Caloric Tests Findings in Noise Induced Hearing Loss-Affected and Healthy Individuals

    Directory of Open Access Journals (Sweden)

    Farinoosh Fakharnia

    2010-06-01

    Full Text Available Background and Aim: Balance disturbance is one of the non-auditory effects of noisy industrial environments that is usually neglected. The aim of the current study was to investigate the effect of occupational noise on vestibular system among workers with noise-induced hearing loss (NIHL, based on both vestibular evoked myogenic potentials (VEMP and caloric tests.Methods: Thirty male workers with noise-induced hearing loss and thirty male matched controls were examined by VEMP and caloric tests. Study parameters included unilateral weakness, p13 and n23 latencies, and p13-n23 amplitude. Caloric test was performed only for 20 patients.Results: No significant difference was observed in unilateral weakness between the two groups. On the other hand, the difference in mean latencies of p13 in the right ear (p=0.003 and left ear (p=0.01 was significant between the two groups. However, the difference in n23 latency was significant only in the right ear (p=0.03. There was no significant difference between groups in p13-n23 amplitude.Conclusion: It seems that pars inferior of vestibule is the susceptible part in individuals with NIHL. In general, abnormal findings in both VEMP and caloric tests were more common compared to functional symptoms such as vertigo, which may be due to central compensation and the symmetry of the disorder.

  3. Reliability-based automatic repeat request for short code modulation visual evoked potentials in brain computer interfaces.

    Science.gov (United States)

    Sato, Jun-Ichi; Washizawa, Yoshikazu

    2015-08-01

    We propose two methods to improve code modulation visual evoked potential brain computer interfaces (cVEP BCIs). Most of BCIs average brain signals from several trials in order to improve the classification performance. The number of averaging defines the trade-off between input speed and accuracy, and the optimal averaging number depends on individual, signal acquisition system, and so forth. Firstly, we propose a novel dynamic method to estimate the averaging number for cVEP BCIs. The proposed method is based on the automatic repeat request (ARQ) that is used in communication systems. The existing cVEP BCIs employ rather longer code, such as 63-bit M-sequence. The code length also defines the trade-off between input speed and accuracy. Since the reliability of the proposed BCI can be controlled by the proposed ARQ method, we introduce shorter codes, 32-bit M-sequence and the Kasami-sequence. Thanks to combine the dynamic averaging number estimation method and the shorter codes, the proposed system exhibited higher information transfer rate compared to existing cVEP BCIs.

  4. Steady-state motion visual evoked potentials produced by oscillating Newton's rings: implications for brain-computer interfaces.

    Directory of Open Access Journals (Sweden)

    Jun Xie

    Full Text Available In this study, we utilize a special visual stimulation protocol, called motion reversal, to present a novel steady-state motion visual evoked potential (SSMVEP-based BCI paradigm that relied on human perception of motions oscillated in two opposite directions. Four Newton's rings with the oscillating expansion and contraction motions served as visual stimulators to elicit subjects' SSMVEPs. And four motion reversal frequencies of 8.1, 9.8, 12.25 and 14 Hz were tested. According to Canonical Correlation Analysis (CCA, the offline accuracy and ITR (mean ± standard deviation over six healthy subjects were 86.56 ± 9.63% and 15.93 ± 3.83 bits/min, respectively. All subjects except one exceeded the level of 80% mean accuracy. Circular Hotelling's T-Squared test (T2 circ also demonstrated that most subjects exhibited significantly strong stimulus-locked SSMVEP responses. The results of declining exponential fittings exhibited low-adaptation characteristics over the 100-s stimulation sequences in most experimental conditions. Taken together, these results suggest that the proposed paradigm can provide comparable performance with low-adaptation characteristic and less visual discomfort for BCI applications.

  5. Intraoperative Combined Use of Somatosensory Evoked Potential, Microvascular Doppler Sonography, and Indocyanine Green Angiography in Clipping of Intracranial Aneurysm

    Science.gov (United States)

    Li, Zhili; Zhang, Guanni; Huang, Guangfu; Wang, Zhengyu; Tan, Haibin; Liu, Jinping; Li, Aiguo

    2016-01-01

    Background The aim of this study was to evaluate the effect of combining application of somatosensory evoked potential (SEP), microvascular Doppler sonography (MDS), and indocyanine green angiography (ICGA) in intracranial aneurysm clipping surgery. Material/Methods A total of 158 patients undergoing an intracranial aneurysm clipping operation were recruited. All patients were evaluated with intraoperative SEP and MDS monitoring, and 28 of them were evaluated with intraoperative combined monitoring of SEP, MDS, and ICGA. Results The SEP waves dropped during temporary occlusion of arteries in 19 cases (12.0%), and returned to normal after the clips were repositioned. After aneurysms were clipped, the vortex flow signals were detected by MDS in 6 cases. The aneurysm neck remnants were detected by ICGA in 2 cases of olfactory artery (OA) and in 1 case of middle cerebral artery (MCA), which disappeared after the clips were repositioned. Postoperative CTA or DSA showed that aneurysms were clipped completely and parent arteries and perforating vessels were patent. GOS at 1 month after the surgery was good in 111 cases (70.3%), mild disability in 22 cases (13.9%), severe disability in 14 cases (8.9%), vegetative state in 5 cases (3.2%), and death in 6 cases (3.8%). Conclusions Intraoperative combining application of SEP, MDS, and ICGA can reduce brain tissue ischemia and damage and disability and mortality rate after effective clipping of intracranial aneurysms, thereby improving surgical outcomes. PMID:26845425

  6. An Enhanced Artifical Broca’s Using High Frequency Steady State Visually Evoked Potential And P300 Based Bci

    Directory of Open Access Journals (Sweden)

    S.ABDUL KHADER

    2013-04-01

    Full Text Available According to All Indian Deaf and Dumb Society (AIDDS there is one in every thousands of people born dumb. There are many reasons for dumbness. Our study is to focus on the problem of dumbness due to paralysis, tongue cancer, Broca’s problem, accident and many more. This critical problem can be solved by using Brain Computer Interface (BCI. However there are lot of obstacles exist in designing a robust BCI. To date, there is no proper sensor interface is available for creating mobile interface and achieving accurate and safe BCI. This paper proposes an enhanced artificial Broca’s BCI using steady state visually evoked potential which gives good accuracy and high transfer rate of neuron signals capture from brain. The proposed technique solves the disability of the handicapped people in safe and accurate manner. Our proposed work combines the features of BCI, mobile and wireless acquisition to create artificial Broca’s that means creating artificial speech production. The proposed technique provide suitable platform under various conditions for different user population with the above said defects and provide consumer ready application.

  7. Auditory evoked potential measurement methodology for odontocetes and a comparison of measured thresholds with those obtained using psychophysical techniques

    Science.gov (United States)

    Nachtigall, Paul E.; Yuen, Michelle; Mooney, T. Aran; Taylor, Kristen

    2005-04-01

    Most measurements of the hearing capabilities of toothed whales and dolphins have been taken using traditional psychophysical procedures in which the animals have been maintained in laboratory environments and trained to behaviorally report the sensation or difference of acoustic stimuli. Because of the advantage of rapid data collection, increased opportunities, and new methods, Auditory Evoked Potentials (AEPs) have become increasingly used to measure audition. The use of this new procedure calls to question the comparability of the established literature and the new results collected with AEPs. The results of behavioral and AEP methods have been directly compared with basic audiogram measurements and have been shown to produce similar (but not exactly the same) values when the envelope following response procedure has been used and the length of the stimulus is taken into account. The AEP methods allow possible audiometric opportunities beyond those available with conventional psychophysics including: (1) the measurement of stranded dolphins and whales that may never be kept in laboratories, (2) the testing of stranded animals for hearing deficits perhaps caused by overexposure to noise, and (3) passive testing of hearing mechanisms while animals actively echolocate. [Work supported by the Office of Naval Research and NOAA-NMFS.

  8. [A wireless smart home system based on brain-computer interface of steady state visual evoked potential].

    Science.gov (United States)

    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.

  9. The multifocal visual evoked potential and cone-isolating stimuli: implications for L- to M-cone ratios and normalization.

    Science.gov (United States)

    Hood, Donald C; Yu, Alice L; Zhang, Xian; Albrecht, Johannes; Jägle, Herbert; Sharpe, Lindsay T

    2002-01-01

    Multifocal visual evoked potentials (mfVEP) were recorded with a pattern-reversing display that modulated only the long wavelength-sensitive (L) cones or only the middle wavelength-sensitive (M) cones. Outside the central 5.8 degrees (radius), the ratio of the amplitudes of the mfVEP responses to L- and M-cone modulation varied across the six subjects, ranging from 1.1 to 1.7. The responses from the central 1 degrees (radius) showed a substantially lower ratio, ranging from 0.8 to 1.1 (average of 0.9). The variation among individuals outside the central fovea is probably due to differences in the ratio of the L/M cone input to both magno- and parvocellular pathways. The substantially lower ratios for the central responses is consistent with an L/M cone ratio closer to 1.0 in the central 1 degrees and/or an adjustment in the gain of the L- versus M-cone contributions to the central parvocellular pathways. Taking into consideration evidence from other techniques, we believe it is unlikely that most individuals have a L/M cone ratio of 1.0 in the fovea. Instead, it appears that there is a change in gain before the mfVEP is generated in area 17.

  10. Cortical Auditory Evoked Potentials Reveal Changes in Audibility with Nonlinear Frequency Compression in Hearing Aids for Children: Clinical Implications.

    Science.gov (United States)

    Ching, Teresa Y C; Zhang, Vicky W; Hou, Sanna; Van Buynder, Patricia

    2016-02-01

    Hearing loss in children is detected soon after birth via newborn hearing screening. Procedures for early hearing assessment and hearing aid fitting are well established, but methods for evaluating the effectiveness of amplification for young children are limited. One promising approach to validating hearing aid fittings is to measure cortical auditory evoked potentials (CAEPs). This article provides first a brief overview of reports on the use of CAEPs for evaluation of hearing aids. Second, a study that measured CAEPs to evaluate nonlinear frequency compression (NLFC) in hearing aids for 27 children (between 6.1 and 16.8 years old) who have mild to severe hearing loss is reported. There was no significant difference in aided sensation level or the detection of CAEPs for /g/ between NLFC on and off conditions. The activation of NLFC was associated with a significant increase in aided sensation levels for /t/ and /s/. It also was associated with an increase in detection of CAEPs for /t/ and /s/. The findings support the use of CAEPs for checking audibility provided by hearing aids. Based on the current data, a clinical protocol for using CAEPs to validate audibility with amplification is presented. PMID:27587920

  11. Short somatosensory evoked potentials in patients with Fukuyama type congenital muscular dystrophy. A comparison with CT and MRI findings

    International Nuclear Information System (INIS)

    Seven patients with Fukuyama type congenital muscular dystrophy were studied. Low density areas (LDs) in the cerebral white matter on cranial CT were present in all 4 patients younger than 13 years of age and in 1 of 3 adult patients. LDs corresponded to low signals on T1 weighted MRI image and high signals on T2 weighted MRI image. The follow-up MRI showed a decreased tendency of the abnormal signals in 2 patients. Short somatosensory evoked potentials (SSEPs) in two infants, aged 4 months and 8 months, showed absent or depressed N1 amplitudes and delayed interpeak latencies from P3 to N1. N1 amplitudes increased on follow-up studies. SSEPs of five patients, who were older than 2 years of age, showed normal N1-P3 latencies. Amplitude of N1 was low in 2 patients with LD. Since the absent or depressed amplitude and delayed latency of N1 improved with the decrease of abnormal signals on MRI, we considered that N1 abnormalities show delayed myelination. (author)

  12. Steady-state visual evoked potentials in the low frequency range in migraine: a study of habituation and variability phenomena.

    Science.gov (United States)

    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.

  13. Nitroglycerin induces migraine headache and central sensitization phenomena in patients with migraine without aura: a study of laser evoked potentials.

    Science.gov (United States)

    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.

  14. Audiogram of a formerly stranded long-finned pilot whale (Globicephala melas) measured using auditory evoked potentials.

    Science.gov (United States)

    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

  15. Clinical Experience of Using Cortical Auditory Evoked Potentials in the Treatment of Infant Hearing Loss in Australia.

    Science.gov (United States)

    Punch, Simone; Van Dun, Bram; King, Alison; Carter, Lyndal; Pearce, Wendy

    2016-02-01

    This article presents the clinical protocol that is currently being used within Australian Hearing for infant hearing aid evaluation using cortical auditory evoked potentials (CAEPs). CAEP testing is performed in the free field at two stimulus levels (65 dB sound pressure level [SPL], followed by 55 or 75 dB SPL) using three brief frequency-distinct speech sounds /m/, /ɡ/, and /t/, within a standard audiological appointment of up to 90 minutes. CAEP results are used to check or guide modifications of hearing aid fittings or to confirm unaided hearing capability. A retrospective review of 83 client files evaluated whether clinical practice aligned with the clinical protocol. It showed that most children could be assessed as part of their initial fitting program when they were identified as a priority for CAEP testing. Aided CAEPs were most commonly assessed within 8 weeks of the fitting. A survey of 32 pediatric audiologists provided information about their perception of cortical testing at Australian Hearing. The results indicated that clinical CAEP testing influenced audiologists' approach to rehabilitation and was well received by parents and that they were satisfied with the technique. Three case studies were selected to illustrate how CAEP testing can be used in a clinical environment. Overall, CAEP testing has been effectively integrated into the infant fitting program. PMID:27587921

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

    Science.gov (United States)

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

    2003-04-01

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

  17. Sex-Specific Automatic Responses to Infant Cries: TMS Reveals Greater Excitability in Females than Males in Motor Evoked Potentials

    Science.gov (United States)

    Messina, Irene; Cattaneo, Luigi; Venuti, Paola; de Pisapia, Nicola; Serra, Mauro; Esposito, Gianluca; Rigo, Paola; Farneti, Alessandra; Bornstein, Marc H.

    2016-01-01

    Neuroimaging reveals that infant cries activate parts of the premotor cortical system. To validate this effect in a more direct way, we used event-related transcranial magnetic stimulation (TMS). Here, we investigated the presence and the time course of modulation of motor cortex excitability in young adults who listened to infant cries. Specifically, we recorded motor evoked potentials (MEPs) from the biceps brachii (BB) and interosseus dorsalis primus (ID1) muscles as produced by TMS delivered from 0 to 250 ms after sound onset in six steps of 50 ms in 10 females and 10 males. We observed an excitatory modulation of MEPs at 100 ms from the onset of infant cry specific to females and to the ID1 muscle. We regard this modulation as a response to natural cry sounds because it was attenuated to stimuli increasingly different from natural cry and absent in a separate group of females who listened to non-cry stimuli physically matched to natural infant cries. Furthermore, the 100-ms latency of this response is not compatible with a voluntary reaction to the stimulus but suggests an automatic, bottom-up audiomotor association. The brains of adult females appear to be tuned to respond to infant cries with automatic motor excitation. PMID:26779061

  18. [Somatosensory evoked potentials in a patient with a posterior postcentral gyrus lesion--generator sources of components after N20].

    Science.gov (United States)

    Johkura, K; Hasegawa, O; Kuroiwa, Y

    1995-05-01

    We studied the distribution of the median nerve somatosensory evoked potentials (SEPs) on the scalp of a 67-year-old woman with a localized old hematoma involving the posterior part of the right postcentral gyrus identified by MRI. The patient presented with an isolated loss of discriminative sensation (stereognosis, graphesthesia and position sense) of the left extremities. With respect to the SEPs on the right hemisphere, the only components remaining were the initial negativity (N20 with latency of about 20 msec) recorded in the parieto-occipital area, which exhibited polarity inversion across the central sulcus. Since area 3b is thought to be the superficial sensory cortex, the results of sensory examination in this case suggested that the hematoma was restricted to areas 1 and 2, which are thought to be the discriminative sensory cortex, and that area 3b was unaffected. We therefore conclude that the N20 on the affected hemisphere reflected the posterior pole of a horizontal dipole generated by area 3b, and that the hematoma abolished the positivity after N20, corresponding to the positive pole of a slightly delayed vertical dipole generated by the posterior part of the postcentral gyrus (areas 1 and 2).

  19. The effect of swallowing treatments on corticobulbar excitability: a review of transcranial magnetic stimulation induced motor evoked potentials.

    Science.gov (United States)

    Macrae, Phoebe R; Jones, Richard D; Huckabee, Maggie-Lee

    2014-08-15

    Transcranial magnetic stimulation (TMS) has been used extensively as a method of investigating the corticomotor physiology of many motor tasks, including healthy and disordered swallowing. Changes in excitability of cortical projections to various swallowing muscles have been documented in response to treatments with TMS induced motor evoked potentials (MEPs). These studies have provided valuable insight into CNS response to swallowing impairment, and more importantly, the adaptations associated with functional recovery. However, unique obstacles are presented when investigating corticobulbar neurophysiology associated with the complex task of swallowing. Stringent methodological control and supplementary outcome measures are required to ensure robust and clinically applicable findings. This article offers a tutorial for the researcher who may be considering the use of TMS for investigating changes in cortical excitability associated with various swallowing paradigms. Included is a review of the mechanisms of TMS and what can be measured with this technique, a summary of existing research using MEPs to investigate swallowing, a review of methodological factors that may influence outcomes, and proposed directions for new areas of research.

  20. Ipsilesional motor-evoked potential absence in pediatric hemiparesis impacts tracking accuracy of the less affected hand.

    Science.gov (United States)

    Cassidy, Jessica M; Carey, James R; Lu, Chiahao; Krach, Linda E; Feyma, Tim; Durfee, William K; Gillick, Bernadette T

    2015-12-01

    This study analyzed the relationship between electrophysiological responses to transcranial magnetic stimulation (TMS), finger tracking accuracy, and volume of neural substrate in children with congenital hemiparesis. Nineteen participants demonstrating an ipsilesional motor-evoked potential (MEP) were compared with eleven participants showing an absent ipsilesional MEP response. Comparisons of finger tracking accuracy from the affected and less affected hands and ipsilesional/contralesional (I/C) volume ratio for the primary motor cortex (M1) and posterior limb of internal capsule (PLIC) were done using two-sample t-tests. Participants showing an ipsilesional MEP response demonstrated superior tracking performance from the less affected hand (p=0.016) and significantly higher I/C volume ratios for M1 (p=0.028) and PLIC (p=0.005) compared to participants without an ipsilesional MEP response. Group differences in finger tracking accuracy from the affected hand were not significant. These results highlight differentiating factors amongst children with congenital hemiparesis showing contrasting MEP responses: less affected hand performance and preserved M1 and PLIC volume. Along with MEP status, these factors pose important clinical implications in pediatric stroke rehabilitation. These findings may also reflect competitive developmental processes associated with the preservation of affected hand function at the expense of some function in the less affected hand. PMID:26426515

  1. Sex-specific automatic responses to infant cries: TMS reveals greater excitability in females than males in motor evoked potentials

    Directory of Open Access Journals (Sweden)

    Irene eMessina

    2016-01-01

    Full Text Available Neuroimaging reveals that infant cries activate parts of the premotor cortical system. To validate this effect in a more direct way, we used event-related transcranial magnetic stimulation (TMS. Here, we investigated the presence and the time course of modulation of motor cortex excitability in young adults who listened to infant cries. Specifically, we recorded motor evoked potentials (MEPs from the biceps brachii (BB and interosseus dorsalis primus (ID1 muscles as produced by TMS delivered from 0 to 250 ms from sound onset in six steps of 50 ms in 10 females and 10 males. We observed an excitatory modulation of MEPs at 100 ms from the onset of the infant cry specific to females and to the ID1 muscle. We regard this modulation as a response to natural cry sounds because it was delayed, attenuated to stimuli increasingly different from natural cry, and was absent in a separate group of females who listened to non-cry stimuli physically matched to natural infant cries. Furthermore, the 100-ms latency of this modulation is not compatible with a voluntary reaction to the stimulus but suggests an automatic, bottom-up audiomotor association. The brains of adult females appear to be tuned to respond to infant cries with automatic motor excitation. This effect may reflect the greater and longstanding burden on females in caregiving infants.

  2. Different Stimulation Frequencies Alter Synchronous Fluctuations in Motor Evoked Potential Amplitude of Intrinsic Hand Muscles-a TMS Study.

    Science.gov (United States)

    Sale, Martin V; Rogasch, Nigel C; Nordstrom, Michael A

    2016-01-01

    The amplitude of motor-evoked potentials (MEPs) elicited with transcranial magnetic stimulation (TMS) varies from trial-to-trial. Synchronous oscillations in cortical neuronal excitability contribute to this variability, however it is not known how different frequencies of stimulation influence MEP variability, and whether these oscillations are rhythmic or aperiodic. We stimulated the motor cortex with TMS at different regular (i.e., rhythmic) rates, and compared this with pseudo-random (aperiodic) timing. In 18 subjects, TMS was applied at three regular frequencies (0.05 Hz, 0.2 Hz, 1 Hz) and one aperiodic frequency (mean 0.2 Hz). MEPs (n = 50) were recorded from three intrinsic hand muscles of the left hand with different functional and anatomical relations. MEP amplitude correlation was highest for the functionally related muscle pair, less for the anatomically related muscle pair and least for the functionally- and anatomically-unrelated muscle pair. MEP correlations were greatest with 1 Hz, and least for stimulation at 0.05 Hz. Corticospinal neuron synchrony is higher with shorter TMS intervals. Further, corticospinal neuron synchrony is similar irrespective of whether the stimulation is periodic or aperiodic. These findings suggest TMS frequency is a crucial consideration for studies using TMS to probe correlated activity between muscle pairs.

  3. Effect of personal music system use on sacculocollic reflex assessed by cervical vestibular-evoked myogenic potential: A preliminary investigation.

    Science.gov (United States)

    Singh, Niraj Kumar; Sasidharan, Chithra Sobha

    2016-01-01

    Listening to music through a portable personal music system (PMS) is a growing trend, especially among the youth. The preferred listening level in such kinds of PMS has been reported to cross the safe levels and its impact on the auditory system was demonstrated in several previous investigations. Owing to the commonality in several aspects between the auditory and the vestibular systems, it appears likely that the deleterious effects of PMS use could also be impinging on the vestibular system, which has never been investigated. The present study therefore, aimed at evaluating the effects of PMS use on the sacculocollic reflex assessed by the cervical vestibular-evoked myogenic potential (cVEMP) technique. Thirty-two regular PMS users and 32 nonregular PMS users underwent cVEMP testing using alternating polarity 500 Hz tone bursts. The results revealed no significant group difference in latencies and interaural asymmetry ratio. However, the cVEMP was significantly reduced in the group of individuals in whom the diffused field equivalent sound pressure levels (SPLs) were above the damage risk criteria (DRC) compared to those with diffused field equivalent SPLs below it (Pvestibular well-being of an individual. PMID:26960788

  4. Effect of personal music system use on sacculocollic reflex assessed by cervical vestibular-evoked myogenic potential: A preliminary investigation

    Directory of Open Access Journals (Sweden)

    Niraj Kumar Singh

    2016-01-01

    Full Text Available Listening to music through a portable personal music system (PMS is a growing trend, especially among the youth. The preferred listening level in such kinds of PMS has been reported to cross the safe levels and its impact on the auditory system was demonstrated in several previous investigations. Owing to the commonality in several aspects between the auditory and the vestibular systems, it appears likely that the deleterious effects of PMS use could also be impinging on the vestibular system, which has never been investigated. The present study therefore, aimed at evaluating the effects of PMS use on the sacculocollic reflex assessed by the cervical vestibular-evoked myogenic potential (cVEMP technique. Thirty-two regular PMS users and 32 nonregular PMS users underwent cVEMP testing using alternating polarity 500 Hz tone bursts. The results revealed no significant group difference in latencies and interaural asymmetry ratio. However, the cVEMP was significantly reduced in the group of individuals in whom the diffused field equivalent sound pressure levels (SPLs were above the damage risk criteria (DRC compared to those with diffused field equivalent SPLs below it (P< 0.01. Therefore, the use of PMS at high levels of volume controls could be deleterious to the vestibular well-being of an individual.

  5. Are There Abnormalities in Peripheral and Central Components of Somatosensory Evoked Potentials in Non-Specific Chronic Low Back Pain?

    Science.gov (United States)

    Puta, Christian; Franz, Marcel; Blume, Kathrin R.; Gabriel, Holger H. W.; Miltner, Wolfgang H. R.; Weiss, Thomas

    2016-01-01

    Chronic low back pain (CLBP) was shown to be associated with longer reflex response latencies of trunk muscles during external upper limb perturbations. One theoretical, but rarely investigated possibility for longer reflex latencies might be related to modulated somatosensory information processing. Therefore, the present study investigated somatosensory evoked potentials (SEPs) to median nerve stimulation in CLBP patients and healthy controls (HC). Latencies of the peripheral N9 SEP component were used as the primary outcome. In addition, latencies and amplitudes of the central N20 SEP component, sensory thresholds, motor thresholds and nerve conduction velocity were also analyzed in CLBP patients and HC. There is a trend for the CLBP patients to exhibit longer N9 latencies at the ipsilateral Erb’s point compared to HC. This trend is substantiated by significantly longer N9 latencies in CLBP patients compared to normative data. None of the other parameters showed any significant difference between CLBP patients and HC. Overall, our data indicate small differences of the peripheral N9 SEP component; however, these differences cannot explain the reflex delay observed in CLBP patients. While it was important to rule out the contribution of early somatosensory processing and to elucidate its contribution to the delayed reflex responses in CLBP patients, further research is needed to find the primary source(s) of time-delayed reflexes in CLBP. PMID:27799904

  6. Effect of personal music system use on sacculocollic reflex assessed by cervical vestibular-evoked myogenic potential: A preliminary investigation

    Science.gov (United States)

    Singh, Niraj Kumar; Sasidharan, Chithra Sobha

    2016-01-01

    Listening to music through a portable personal music system (PMS) is a growing trend, especially among the youth. The preferred listening level in such kinds of PMS has been reported to cross the safe levels and its impact on the auditory system was demonstrated in several previous investigations. Owing to the commonality in several aspects between the auditory and the vestibular systems, it appears likely that the deleterious effects of PMS use could also be impinging on the vestibular system, which has never been investigated. The present study therefore, aimed at evaluating the effects of PMS use on the sacculocollic reflex assessed by the cervical vestibular-evoked myogenic potential (cVEMP) technique. Thirty-two regular PMS users and 32 nonregular PMS users underwent cVEMP testing using alternating polarity 500 Hz tone bursts. The results revealed no significant group difference in latencies and interaural asymmetry ratio. However, the cVEMP was significantly reduced in the group of individuals in whom the diffused field equivalent sound pressure levels (SPLs) were above the damage risk criteria (DRC) compared to those with diffused field equivalent SPLs below it (P < 0.01). Therefore, the use of PMS at high levels of volume controls could be deleterious to the vestibular well-being of an individual. PMID:26960788

  7. Characterization of the cerebral activity by time–frequency representation of evoked EEG potentials

    International Nuclear Information System (INIS)

    Event-related brain potentials (ERPs) are the electrical response of the brain while performing a particular task. Methods traditionally used to study ERPs measure the amplitude and duration of the waveform in order to quantify the changes, being signal morphology dependent. However, the frequency characteristics of those events remain uncovered. The aim of this work was the study of new measures to characterize, by means of time–frequency representation (TFR) techniques, the ERPs recorded while subjects conducted a choice reaction time task (Ericksen flanker task) following the administration of different alprazolam doses. Several measures defined from energy, instantaneous frequency and group delay functions were obtained by means of TFR techniques applied to the Choi–Williams distribution (CWD) of EEG signals. These measures, which are signal morphology independent, were studied in four frequency bands, δ (0–4 Hz), θ (4–8 Hz), α (8–15 Hz), β (15–30 Hz), and for certain time periods. Based on these measures, differences between ERPs were analyzed by comparing the different response types (successes or successfully corrected failures) of the subject performing the task, and comparing the applied drug doses. For each subject, the CWD of EEG signals was applied in two different ways: (a) all ERPs were averaged per channel, and then the CWD was applied; (b) the CWD was applied to each one of the ERPs. When the CWD was applied to each ERP, the energy measures in the δ, θ and β bands, the instantaneous frequency measures in the α and β bands, and the group delay measures in the δ, θ and α bands showed a statistically significant level p < 0.0005 in the analysis of the response type. Also, the energy measures in the θ and β bands and the instantaneous frequency measures in the α band showed statistically significant differences (p < 0.0005) between placebo and low and high drug doses. In contrast, poor results were obtained when all epochs of

  8. Effect Of Electromagnetic Waves Emitted From Mobile Phone On Brain Stem Auditory Evoked Potential In Adult Males.

    Science.gov (United States)

    Singh, K

    2015-01-01

    Mobile phone (MP) is commonly used communication tool. Electromagnetic waves (EMWs) emitted from MP may have potential health hazards. So, it was planned to study the effect of electromagnetic waves (EMWs) emitted from the mobile phone on brainstem auditory evoked potential (BAEP) in male subjects in the age group of 20-40 years. BAEPs were recorded using standard method of 10-20 system of electrode placement and sound click stimuli of specified intensity, duration and frequency.Right ear was exposed to EMW emitted from MP for about 10 min. On comparison of before and after exposure to MP in right ear (found to be dominating ear), there was significant increase in latency of II, III (p < 0.05) and V (p < 0.001) wave, amplitude of I-Ia wave (p < 0.05) and decrease in IPL of III-V wave (P < 0.05) after exposure to MP. But no significant change was found in waves of BAEP in left ear before vs after MP. On comparison of right (having exposure routinely as found to be dominating ear) and left ears (not exposed to MP), before exposure to MP, IPL of IIl-V wave and amplitude of V-Va is more (< 0.001) in right ear compared to more latency of III and IV wave (< 0.001) in left ear. After exposure to MP, the amplitude of V-Va was (p < 0.05) more in right ear compared to left ear. In conclusion, EMWs emitted from MP affects the auditory potential. PMID:27530007

  9. Effect of scorpion venom analgesic active peptide extracted from Buthus martensii Karsch on evoked potential in the thalamic posterior nucleus group in rats

    Institute of Scientific and Technical Information of China (English)

    Qiuhong Lin; Xinxin Li

    2008-01-01

    BACKGROUND: Buthus martensii Karsch is a rare medicinal animal, and dried integral Buthus martensii Karsch is an important drug in traditional Chinese medicine. OBJECTIVE: To investigate the effects of scorpion venom analgesic active peptide (SAP) extracted from Buthus martensii Karsch on evoked unit discharge of the common peroneal nerve in the posterior nucleus group of the thalamus using a stereotaxic electrophysiological extracellular microelectrode recording. DESIGN, TIME AND SETTING: One-way designed study, performed in the Physiological Laboratory of Shenyang Medical College on September 15, 2006. MATERIALS: Fifty 3-4 months old Wistar rats (25 males and 25 females) were used. SAP was provided by Shenyang Pharmaceutical University. Morphine solution was made by the First Drug Manufactory, Northeastern Drug Manufacture Group (batch number: H20013351). Naloxone solution was made by Hunan Pharmaceutical Co., Ltd. (batch number: H43021669). Type ATAC-350 medical data processing equipment was made by the Photoelectricity Company, Japan.MAIN OUTCOME MEASURES: Evoked discharge in the posterior nucleus group of the thalamus and effects of SAP alone and SAP in combination with saline, morphine, or naloxone on discharges in the posterior nucleus group of the thalamus as measured by TQ-19 medical data processing equipment.RESULTS: SAP group: At 1-3 minutes after SAP injection, evoked discharges in the posterior nucleus group of the thalamus were inhibited, and the inhibitory time lasted for (45.0?.7) minutes. Saline group: Evoked discharges in the posterior nucleus group of the thalamus did not change after saline injection. Morphine group: At 1-3 minutes after morphine injection, evoked discharges in the posterior nucleus group of the thalamus were inhibited, and the inhibitory time lasted for (35.0?.8) minutes. Naloxone group: SAP had no effects on evoked potentials in the posterior nucleus group of the thalamus.

  10. Effects of the ephedra alkaloid methylephedrine on the basal evoked potential transportation and the long-term potentiation (LTP) in the rat hippocampal dentate granule cells in vivo

    Institute of Scientific and Technical Information of China (English)

    PENG Xiao-dong

    2008-01-01

    Objective The effect of the ephedra/ephedrine alkaloid methylephedrine (dl-methylephedrine hydrochloride for testing in this paper) on cognitive related synaptic plasticity was investigated by recording extracellular field evoked potentials and its LTP in hippocampal dentate granule cells in urethane-anaesthetized rats in vivo. Methods Single pathway recording of evoked field potentials was made from the dentate granule cells of hippocampal hemisphere in response to stimulation of the ipsilateral medial perforant path (MPP). Two parameters, the amplitude of population spike (PS amplitude) and the latency of the PS, were employed to evaluate the effects of drug on the overall changes in cellular responses. Results The present study show that methylephedrine 90 mg·kg-1 intraperitoneally, about 1/3 LD50, could increase the latency of the PS in hippocampal dentate granule cells by constant single stimulation of the MPP as the basal ransportation. However, the 30 mg·kg-1 and 10 mg·kg-1 dosage had no effect on the latency, and there are no influences of PS amplitude for all examinational groups. The methylephedrine 90 mg·kg-1 group significant enhanced the development of amplitude LTP in hippocampal dentate granule cells that induced by 60 Hz, 60 pulses conditional tetanus in medial perforant path area. Also, the 30 mg·kg-1 group can promoted the maintenance of LTP induced by this tetanus, but no promotion on PS amplitude LTP appeared in this dosage and no any changes been found in 10 mg·kg-1 dosage group. Conclusions The ephedra/ephedrine alkaloid methylephedrine can modulate the synaptic plasticity in the lateral perforant path. A possible mechanism of methylephedrine on hippocampal LTP is been discussed.

  11. Correlation analysis of the long latency auditory evoked potential N2 and cognitive P3 with the level of lead poisoning in children

    Directory of Open Access Journals (Sweden)

    Alvarenga, Kátia de Freitas

    2013-01-01

    Full Text Available Introduction: The effects of lead on children's health have been widely studied. Aim: To analyze the correlation between the long latency auditory evoked potential N2 and cognitive P3 with the level of lead poisoning in Brazilian children. Methods: This retrospective study evaluated 20 children ranging in age from 7 to 14 years at the time of audiological and electrophysiological evaluations. We performed periodic surveys of the lead concentration in the blood and basic audiological evaluations. Furthermore, we studied the auditory evoked potential long latency N2 and cognitive P3 by analyzing the absolute latency of the N2 and P3 potentials and the P3 amplitude recorded at Cz. At the time of audiological and electrophysiological evaluations, the average concentration of lead in the blood was less than 10 ug/dL. Results: In conventional audiologic evaluations, all children had hearing thresholds below 20 dBHL for the frequencies tested and normal tympanometry findings; the auditory evoked potential long latency N2 and cognitive P3 were present in 95% of children. No significant correlations were found between the blood lead concentration and latency (p = 0.821 or amplitude (p = 0.411 of the P3 potential. However, the latency of the N2 potential increased with the concentration of lead in the blood, with a significant correlation (p = 0.030. Conclusion: Among Brazilian children with low lead exposure, a significant correlation was found between blood lead levels and the average latency of the auditory evoked potential long latency N2; however, a significant correlation was not observed for the amplitude and latency of the cognitive potential P3.

  12. Critical Utopian Action Research: The Potential of Action Research in the Democratization of Society

    DEFF Research Database (Denmark)

    Nielsen, Birger Steen; Nielsen, Kurt Aagaard

    2016-01-01

    The specific concept of critical utopian action research is presented and discussed, as to its origin, use and potentials. The inspiration from Robert Jungk and his future creating workshops is elaborated....

  13. Three-channel Lissajous' trajectories of auditory brainstem evoked potentials: contribution of fast and slow components to planar segment formation.

    Science.gov (United States)

    Pratt, H; Bleich, N; Feingold, K

    1990-01-01

    Three-Channel Lissajous' Trajectories (3CLT) of Auditory Brainstem Evoked Potentials (ABEP) to clicks were obtained after finite impulse response filtering in three frequency bands. These bands were chosen to replicate the widely used passband (100-3000 Hz) and to selectively enhance the definition of the 'pedestal' (10-240 Hz) or the first, third and fifth components (240-483 Hz). Quantitative measures of 3CLT were calculated to describe apex latencies, planar segment orientations, durations, trajectory amplitude peaks and their latencies. In addition, dipole moments at the latencies of apical points along 3-CLT were calculated. The planarity of ABEP 3-CLT segments persisted after selective enhancement of the 'pedestal' or the first, third and fifth components. These results rule out the suggestion that planarity of ABEP segments results from the interaction of the 'pedestal' with the superimposed faster components. These results demonstrate summation of 3-CLT planar segments ('a' 'c' and 'e' with the 'pedestal') to form new segments (wide-band 'a', 'c' and 'e'). With the exception of 'c', planar segments and the equivalent dipole moments associated with apexes did not change orientations across passbands. The effects of passband on the orientation of planar segment 'c' and the dipole moment of its apex are explained by its superimposition on the 'pedestal' in the wide-band records. A similar analysis of ABEP to clicks as compared to low-frequency stimuli (high-pass masked clicks) revealed no change in planarity nor in plane parameters. These results are compatible with the suggestion that the generators of the first, third and fifth ABEP components are curved fiber tracts. The planarity of the slow 'pedestal' may be due to the summation of slow synaptic potentials in auditory brainstem nuclei. These findings indicate that the generators of ABEP are composites that may be separated by selective lesion studies. PMID:2312411

  14. Developing an online steady-state visual evoked potential-based brain-computer interface system using EarEEG.

    Science.gov (United States)

    Wang, Yu-Te; Nakanishi, Masaki; Kappel, Simon Lind; Kidmose, Preben; Mandic, Danilo P; Wang, Yijun; Cheng, Chung-Kuan; Jung, Tzyy-Ping

    2015-01-01

    The purpose of this study is to demonstrate an online steady-state visual evoked potential (SSVEP)-based BCI system using EarEEG. EarEEG is a novel recording concept where electrodes are embedded on the surface of earpieces customized to the individual anatomical shape of users' ear. It has been shown that the EarEEG can be used to record SSVEPs in previous studies. However, a long distance between the visual cortex and the ear makes the signal-to-noise ratio (SNR) of SSVEPs acquired by the EarEEG relatively low. Recently, filter bank- and training data-based canonical correlation analysis algorithms have shown significant performance improvement in terms of accuracy of target detection and information transfer rate (ITR). This study implemented an online four-class SSVEP-based BCI system using EarEEG. Four subjects participated in offline and online BCI experiments. For the offline classification, an average accuracy of 82.71±11.83 % was obtained using 4 sec-long SSVEPs acquired from earpieces. In the online experiment, all subjects successfully completed the tasks with an average accuracy of 87.92±12.10 %, leading to an average ITR of 16.60±6.55 bits/min. The results suggest that EarEEG can be used to perform practical BCI applications. The EarEEG has the potential to be used as a portable EEG recordings platform, that could enable real-world BCI applications. PMID:26736745

  15. Influence of the metabolic control on latency values of visual evoked potentials (VEP) in patients with diabetes mellitus type 1.

    Science.gov (United States)

    Matanovic, Dragana; Popovic, Srdjan; Parapid, Biljana; Petronic, Ivana; Cirovic, Dragana; Nikolic, Dejan

    2012-12-01

    The aim of our study was to investigate the relationship between the metabolic control parameters of diabetes mellitus (glycemia and HbA1c) and visual evoked potentials (VEP) latency values. The study included 61 patients with diabetes mellitus type 1 that were hospitalized at the Clinic for Endocrinology, Diabetes and Metabolic Diseases due to the poor metabolic control. All patients were divided into 3 groups. Group 1 consisted of patients on conventional insulin therapy (CT); Group 2 included patients on CT at the moment of hospitalization, with a change towards intensified insulin therapy (IIT); and Group 3 consisted of patients on IIT. Patients with diabetic retinopathy (DR) were excluded from the study. Metabolic control (glycemia and HbA1c) and VEP parameters were compared at the beginning of the study and six months later. After six months of strict glycoregulation, significant improvement in VEP parameters was followed by significant improvement of evaluated parameters of metabolic control. We found statistically significant reduction in frequency of pathological VEP findings, prolonged P100 latency and low amplitude potentials in Group 2, while in Groups 1 and 3 we found that these parameters did not significantly changed but the frequencies were lower. The VEP testing is a noninvasive diagnostic procedure which may help in early diagnosis of DR, prognosis during the metabolic control and treatment. If changes in the retina could be detected before DR is noticed using this noninvasive diagnostic procedure and include patients in a strict glycoregulation, we could be in the position to prevent serious complications that may cause blindness. PMID:23479458

  16. Cervical vestibular evoked myogenic potentials in children with spastic cerebral palsy and normal children with 7-12 years of age

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    Nazila Akbarfahimi

    2014-10-01

    Full Text Available Background and Aim: Cervical vestibular-evoked myogenic potential (cVEMP is one of the diagnostic tests used in assessing vestibular function. Two aims of this study were to investigate implications of cervical vestibular evoked myogenic potential in children with spastic cerebral palsy (7-12 years, and to compare vestibular function in these children and normal children.Methods: In this cross-sectional study, myogenic potential was recorded in 31 children with spastic cerebral palsy (8 girls, 23 boys,7-12 years of age, with mean age of 8.77 years old and standard deviation of 1.52 years and 31 normal children (13 girls, 18 boys with mean age of 8.77 years and standard deviation of 1.52 years. Cervical vestibular evoked myogenic potential was recorded with 500 Hz tone burst. The recorded parameters included p13 and n23 latency, p13-n23 pick to pick amplitude, and threshold.Results: Myogenic Potential was recorded in 31 normal children. They had bilateral responses. In children with cerebral palsy, 21 children showed bilateral responses, 3 children had only right-sided responses, 8 children had only left-sided responses, and two children did not show any responses. The statistical significant differences were shown between the two groups in n23, p13-n23 pick to pick amplitude, and threshold (p<0.05.Conclusion: These findings showed that cervical vestibular evoked myogenic potential can be used in children with cerebral palsy. There were significant differences in myogenic potential parameters between the two groups. More studies are needed to investigate the causes of these differences.

  17. [Anesthesia with flunitrazepam/fentanyl and isoflurane/fentanyl. Unconscious perception and mid-latency auditory evoked potentials].

    Science.gov (United States)

    Schwender, D; Kaiser, A; Klasing, S; Faber-Züllig, E; Golling, W; Pöppel, E; Peter, K

    1994-05-01

    There is a high incidence of intraoperative awareness during cardiac surgery. Mid-latency auditory evoked potentials (MLAEP) reflect the primary cortical processing of auditory stimuli. In the present study, we investigated MLAEP and explicit and implicit memory for information presented during cardiac anaesthesia. PATIENTS AND METHODS. Institutional approval and informed consent was obtained in 30 patients scheduled for elective cardiac surgery. Anaesthesia was induced in group I (n = 10) with flunitrazepam/fentanyl (0.01 mg/kg) and maintained with flunitrazepam/fentanyl (1.2 mg/h). The patients in group II (n = 10) received etomidate (0.25 mg/kg) and fentanyl (0.005 mg/kg) for induction and isoflurane (0.6-1.2 vol%)/fentanyl (1.2 mg/h) for maintenance of general anaesthesia. Group III (n = 10) served as a control and patients were anaesthetized as in I or II. After sternotomy an audiotape that included an implicit memory task was presented to the patients in groups I and II. The story of Robinson Crusoe was told, and it was suggested to the patients that they remember Robinson Crusoe when asked what they associated with the word Friday 3-5 days postoperatively. Auditory evoked potentials were recorded awake and during general anaesthesia before and after the audiotape presentation on vertex (positive) and mastoids on both sides (negative). Auditory clicks were presented binaurally at 70 dBnHL at a rate of 9.3 Hz. Using the electrodiagnostic system Pathfinder I (Nicolet), 1000 successive stimulus responses were averaged over a 100 ms poststimulus interval and analyzed off-line. Latencies of the peak V, Na, Pa were measured. V belongs to the brainstem-generated potentials, which demonstrates that auditory stimuli were correctly transduced. Na, Pa are generated in the primary auditory cortex of the temporal lobe and are the electrophysiological correlate of the primary cortical processing of the auditory stimuli. RESULTS. None of the patients had an explicit memory

  18. 眼肌前庭诱发肌源性电位的研究现状及展望%Present situation and development of ocular vestibular-evoked myogenic potential

    Institute of Scientific and Technical Information of China (English)

    胡娟; 张青

    2013-01-01

    Myogenic potentials evoked by air conducted sound (ACS) , bone conducted vibration (BCV) or galvanic pulses can be recorded with surface electrodes over contracted muscles. These myogenic potentials are of vestibular origin (utricle and saccule) and so these potentials are called vestibular evoked myogenic potentials (VEMPs). Since the vestibular system has projections to many muscle systems, there are many such VEMPs. In this review, we discuss the generated origin, response pathway, waveform characteristics and clinical application of ocular vestibular-evoked myogenic potential(oVEMP).

  19. Potencial evocado somatossensitivo e motor na espodilose cervical Somatosensory and motor evoked potentials in patients with cervical spondylosis

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    Daniela Oliveira de Andrade

    2005-09-01

    Full Text Available Foram estudados 54 pacientes com diagnóstico de espondilose cervical (EC com ou sem sinais clínicos de mielopatia espondilótica. Realizou-se análise retrospectiva de todos os pacientes portadores de EC investigados por ressonância magnética (RNM cervical, potenciais evocados somatossensitivos (PESS e motor (PEM de membros superiores e inferiores. A RNM foi considerada padrão-ouro e os pacientes foram divididos em três grupos. Grupo 1 (RNM sem compressão medular, Grupo 2 (apenas indentação medular e grupo 3 (compressão medular associada a alteração do sinal medular. A sensibilidade do PESS de quatro membros foi 61,9%, similar à encontrada quando realizado o PESS apenas de membros inferiores. A sensibilidade do PEM de quatro membros foi 71,4%, em membros superiores isoladamente foi 66,7% e em membros inferiores 52,4%, mostrando a importância da realização deste método nos quatro membros quando suspeita-se de mielopatia espondilótica cervical. Os resultados encontrados pelo estudo do nervo tibial no PESS e do músculo abdutor do dedo mínimo no PEM mostrou maior percentual de achados alterados que os resultados encontrados pelo estudo do nervo mediano no PESS e do músculo extensor curto dos dedos no PEM nos três grupos, sugerindo que existe um comprometimento inicial deles.This study investigated 54 patients with cervical spondylosis (CS with or without symptoms caused by cervical spondylotic myelopathy. Cervical MRI, somatosensory evoked potentials (SEPs and motor evoked potentials (MEP from upper and lower limbs of all of these patients were examined retrospectively. Were MRI findings the gold standard and the patients were classified in three groups. Group 1 (absence of spinal cord compression ; Group 2 ( presence of spinal cord indentation; Group 3 (spinal cord compression with alteration of intraspinal sign. The sensitivity of SEP of four limbs was 61.9%, the same one as the SEP of lower limbs. The sensitivity of MEP of

  20. Role of Sodium Channel on Cardiac Action Potential

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    S. H. Sabzpoushan

    2012-06-01

    Full Text Available Sudden cardiac death is a major cause of death worldwide. In most cases, it's caused by abnormal action potential propagation that leads to cardiac arrhythmia. The aim of this article is to study the abnormal action potential propagation through sodium ion concentration variations. We use a new electrophysiological model that is both detailed and computationally efficient. This efficient model is based on the partial differential equation method. The central finite difference method is used for numerical solving of the two-dimensional (2D wave propagation equation. Simulations are implemented in two stages, as a single cardiac cell and as a two-dimensional grid of cells. In both stages, the normal action potential formation in case of a single cell and it's normal propagation in case of a two-dimensional grid of cells were simulated with nominal sodium ion conductance. Then, the effect of sodium ion concentration on the action potential signal was studied by reducing the sodium ion conductance. It is concluded that reducing the sodium ion conductance, decreases both passing ability and conduction velocity of the action potential wave front.

  1. Assessing the Quality of Steady-state Visual-evoked Potentials for Moving Humans Using a Mobile Electroencephalogram Headset

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    Yuan-Pin eLin

    2014-03-01

    Full Text Available Recent advances in mobile electroencephalogram (EEG systems, featuring non-prep dry electrodes and wireless telemetry, have urged the needs of mobile brain-computer interfaces (BCIs for applications 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 systemati-cally 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 con-currently 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.

  2. Sensitivity of cortical auditory evoked potential detection for hearing-impaired infants in response to short speech sounds

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    Bram Van Dun

    2012-01-01

    Full Text Available

    Background: Cortical auditory evoked potentials (CAEPs are an emerging tool for hearing aid fitting evaluation in young children who cannot provide reliable behavioral feedback. It is therefore useful to determine the relationship between the sensation level of speech sounds and the detection sensitivity of CAEPs.

    Design and methods: Twenty-five sensorineurally hearing impaired infants with an age range of 8 to 30 months were tested once, 18 aided and 7 unaided. First, behavioral thresholds of speech stimuli /m/, /g/, and /t/ were determined using visual reinforcement orientation audiometry (VROA. Afterwards, the same speech stimuli were presented at 55, 65, and 75 dB SPL, and CAEP recordings were made. An automatic statistical detection paradigm was used for CAEP detection.

    Results: For sensation levels above 0, 10, and 20 dB respectively, detection sensitivities were equal to 72 ± 10, 75 ± 10, and 78 ± 12%. In 79% of the cases, automatic detection p-values became smaller when the sensation level was increased by 10 dB.

    Conclusions: The results of this study suggest that the presence or absence of CAEPs can provide some indication of the audibility of a speech sound for infants with sensorineural hearing loss. The detection of a CAEP provides confidence, to a degree commensurate with the detection probability, that the infant is detecting that sound at the level presented. When testing infants where the audibility of speech sounds has not been established behaviorally, the lack of a cortical response indicates the possibility, but by no means a certainty, that the sensation level is 10 dB or less.

  3. Double function of noninvasive intracranial pressure monitoring based on flash visual evoked potentials in unconscious patients with traumatic brain injury.

    Science.gov (United States)

    Wang, Tingzhong; Ma, Shuang; Guan, Yongchang; Du, Jinghua; Liu, Guojun; Zhao, Xianlin

    2016-05-01

    Intracranial pressure (ICP) monitoring based on flash visual evoked potentials (F-VEP) is a noninvasive method of monitoring ICP. The early diagnosis of traumatic optic neuropathy (TON) in unconscious patients with traumatic brain injury (TBI) is a challenge. The aim of this study was to evaluate the function of F-VEP ICP monitoring in predicting TON and detecting contusion enlargement (CE) in unconscious TBI patients using a modified approach. A series of F-VEP ICP-monitored unconscious TBI patients were included in the study. The interocular differences in N2 wave latency (DL) and amplitude (DA) were obtained through monocular flash stimulation. The increases in ICP (dxP) and interchannel difference (dxDC) across various time points were obtained through binocular flash stimulation. The predictive power of DL and DA on TON, as well as of dxP and dxDC on CE, was assessed by logistic regression and receiver operating characteristic (ROC) curve analysis. Patients with TON had a longer DL and a higher DA than those without TON. The dxP and dxDC of patients with CE were both higher than those of patients without CE. The differences were statistically significant. The logistic regression showed that both DL and DA were predictors of TON, whereas only dxDC was a predictor of CE. However, the ROC curve analysis showed that DL had greater predictive power for TON, and dxDC had greater predictive power for CE. An F-VEP ICP monitoring system with a modified approach is beneficial for early diagnosis of TON and prediction of CE in unconscious TBI patients. PMID:26922509

  4. Intraoperative somatosensory evoked potential recovery following opening of the fourth ventricle during posterior fossa decompression in Chiari malformation: case report.

    Science.gov (United States)

    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.

  5. Comparison of the reliability of multifocal visual evoked cortical potentials generated by pattern reversal and pattern pulse stimulation

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    G.S. Souza

    2012-10-01

    Full Text Available This study compared the effectiveness of the multifocal visual evoked cortical potentials (mfVEP elicited by pattern pulse stimulation with that of pattern reversal in producing reliable responses (signal-to-noise ratio >1.359. Participants were 14 healthy subjects. Visual stimulation was obtained using a 60-sector dartboard display consisting of 6 concentric rings presented in either pulse or reversal mode. Each sector, consisting of 16 checks at 99% Michelson contrast and 80 cd/m² mean luminance, was controlled by a binary m-sequence in the time domain. The signal-to-noise ratio was generally larger in the pattern reversal than in the pattern pulse mode. The number of reliable responses was similar in the central sectors for the two stimulation modes. At the periphery, pattern reversal showed a larger number of reliable responses. Pattern pulse stimuli performed similarly to pattern reversal stimuli to generate reliable waveforms in R1 and R2. The advantage of using both protocols to study mfVEP responses is their complementarity: in some patients, reliable waveforms in specific sectors may be obtained with only one of the two methods. The joint analysis of pattern reversal and pattern pulse stimuli increased the rate of reliability for central sectors by 7.14% in R1, 5.35% in R2, 4.76% in R3, 3.57% in R4, 2.97% in R5, and 1.78% in R6. From R1 to R4 the reliability to generate mfVEPs was above 70% when using both protocols. Thus, for a very high reliability and thorough examination of visual performance, it is recommended to use both stimulation protocols.

  6. Multifocal and pattern-reversal visual evoked potentials vs. automated perimetry frequency-doubling technology matrix in optic neuritis

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    Marcella Nebbioso

    2013-01-01

    Full Text Available Background: To compare the usefulness of the traditional pattern-reversal Visual Evoked Potentials (VEP with multifocal VEP (mfVEP and Frequency-Doubling Technology (FDT perimetry in the evaluation of the ocular abnormalities induced by acute or subacute optic neuritis (ON. Materials and Methods: The test results of 24 ON patients were compared with those obtained in 40 normal control subjects. MfVEP recordings were obtained by using an Optoelectronic Stimulator that extracts topographic VEP using a pseudorandom m-sequence stimulus. Receiver operator characteristic (ROC curves were calculated to determine the sensitivity and specificity of abnormal values. Results: The frequency of the abnormal ocular findings differed in the ON patients according to the used technique. Reduced visual sensitivity was demonstrated in 12 eyes (54.5% using FDT perimetry; 17 eyes (77.2% showed decreased amplitude and/or an increase in the implicit time of the P1 wave in mfVEP and 20 eyes (90.9% showed an abnormal decrease in the amplitude and/or an increase in the latency of the P100 peak at VEP examination. The areas under the ROC curves ranged from 0.743 to 0.935, with VEP having the largest areas. The VEP and mfVEP amplitudes and latencies yielded the greatest sensitivity and specificity. Conclusions: The mfVEP and the FDT perimetry can be used for the evaluation and monitoring of visual impairment in patients with ON. The most sensitive and practical diagnostic tool in patients with ON is, however, the traditional VEP. The mfVEP can be utilized in those cases with doubtful or negative VEP results.

  7. Investigation and Comparison of Recording Time of Steady State Evoked Potentials Using Three Methods of Kalman, Ziarani and adaptive

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    Ali Reza Mehri

    2007-06-01

    Full Text Available Background and Aim: Hearing assessment in infants and children younger than two years is an impor­tant issue, because the golden time of the language learning and speaking is under the age of two. Steady state auditory evoked potentials (SSAEPs is one of the best ways of the objective hearing assess­ment for infants and young children. The need for long time of stimulation and recording re­stricted the clinical uses of this method. Therefore, the reduction of the recording time is a common prob­lem. SSAEP signals are contaminated with background EEG signals of the brain and nervous sys­tem. To discriminate these signals the approach is using averaging method.Materials and Methods: In this work two adaptive methods were programmed and tried on (SSAEP sig­nals. The first method was the work of the Ziarani et al. and the second was the enhanced Kalman fil­ter. To assess suggested methods and to compare them with traditional averaging one, two sets of clini­cal signals prepared with Rotmen research group in university of Toronto were applied. Results: The speed of the extraction of the SSAEP signals with the Ziarani method is 1.6 times faster than the averaging method. The extraction time of the enhanced adaptive Kalman filter is 13.1 times faster than currently used averaging methods. Conclusion: The Kalman filter method seems to be more reliable than the other two methods. In addi­tion, this new application of the Kalman filter in hearing assessment could be more beneficial and faster than other methods as an objective method.

  8. Comparison of the reliability of multifocal visual evoked cortical potentials generated by pattern reversal and pattern pulse stimulation.

    Science.gov (United States)

    Souza, G S; Schakelford, H B; Moura, A L A; Gomes, B D; Ventura, D F; Fitzgerald, M E C; Silveira, L C L

    2012-10-01

    This study compared the effectiveness of the multifocal visual evoked cortical potentials (mfVEP) elicited by pattern pulse stimulation with that of pattern reversal in producing reliable responses (signal-to-noise ratio >1.359). Participants were 14 healthy subjects. Visual stimulation was obtained using a 60-sector dartboard display consisting of 6 concentric rings presented in either pulse or reversal mode. Each sector, consisting of 16 checks at 99% Michelson contrast and 80 cd/m² mean luminance, was controlled by a binary m-sequence in the time domain. The signal-to-noise ratio was generally larger in the pattern reversal than in the pattern pulse mode. The number of reliable responses was similar in the central sectors for the two stimulation modes. At the periphery, pattern reversal showed a larger number of reliable responses. Pattern pulse stimuli performed similarly to pattern reversal stimuli to generate reliable waveforms in R1 and R2. The advantage of using both protocols to study mfVEP responses is their complementarity: in some patients, reliable waveforms in specific sectors may be obtained with only one of the two methods. The joint analysis of pattern reversal and pattern pulse stimuli increased the rate of reliability for central sectors by 7.14% in R1, 5.35% in R2, 4.76% in R3, 3.57% in R4, 2.97% in R5, and 1.78% in R6. From R1 to R4 the reliability to generate mfVEPs was above 70% when using both protocols. Thus, for a very high reliability and thorough examination of visual performance, it is recommended to use both stimulation protocols. PMID:22782556

  9. Noxious mechanical heterotopic stimulation induces inhibition of the spinal dorsal horn neuronal network: analysis of spinal somatosensory-evoked potentials.

    Science.gov (United States)

    Meléndez-Gallardo, J; Eblen-Zajjur, A

    2016-09-01

    Most of the endogenous pain modulation (EPM) involves the spinal dorsal horn (SDH). EPM including diffuse noxious inhibitory controls have been extensively described in oligoneuronal electrophysiological recordings but less attention had been paid to responses of the SDH neuronal population to heterotopic noxious stimulation (HNS). Spinal somatosensory-evoked potentials (SEP) offer the possibility to evaluate the neuronal network behavior, reflecting the incoming afferent volleys along the entry root, SDH interneuron activities and the primary afferent depolarization. SEP from de lumbar cord dorsum were evaluated during mechanical heterotopic noxious stimuli. Sprague-Dawley rats (n = 12) were Laminectomized (T10-L3). The sural nerve of the left hind paw was electrically stimulated (5 mA, 0.5 ms, 0.05 Hz) to induce lumbar SEP. The HNS (mechanic clamp) was applied sequentially to the tail, right hind paw, right forepaw, muzzle and left forepaw during sural stimulation. N wave amplitude decreases (-16.6 %) compared to control conditions when HNS was applied to all areas of stimulation. This effect was more intense for muzzle stimulation (-23.5 %). N wave duration also decreased by -23.6 %. HNS did not change neither the amplitude nor the duration of the P wave but dramatically increases the dispersion of these two parameters. The results of the present study strongly suggest that a HNS applied to different parts of the body is able to reduce the integrated electrical response of the SDH, suggesting that not only wide dynamic range neurons but many others in the SDH are modulated by the EPM. PMID:27207681

  10. Neural Consequences of Increasing Body Weight: Evidence from Somatosensory Evoked Potentials and the Frequency-Specificity of Brain Oscillations

    Science.gov (United States)

    Lhomond, Olivia; Teasdale, Normand; Simoneau, Martin; Mouchnino, Laurence

    2016-01-01

    Previous studies on the control of human balance suggested that increased pressure under the feet, leading to reduced plantar sole mechanoreceptors sensitivity, increases body sway. Although this suggestion is attracting, it is unclear whether increased plantar sole pressure simply reduces the transmission of plantar sole afferent to the cortex or also alters the sensorimotor integrative mechanisms. Here we used electrical stimulation applied under the sole of the foot to probe the sensorimotor mechanisms processing foot mechanoreceptors. Balance control of healthy individuals was assessed either when wearing a loaded vest or in normal-weight condition. In the Loaded condition, we observed decreased cortical activity over the primary somatosensory cortex (SI) for both an early P50-N90 somatosensory evoked potential (SEP) and for oscillatory brain activity within the gamma band (30–80 Hz). These reductions were interpreted as a disrupted early sensory transmission (i.e., decreased early SEP) leading to a decreased perception of plantar sole sensory information (i.e., decreased gamma band power). These early sensory mechanisms for the Loaded condition were associated with an increase in the late P170-N210 SEP and oscillatory brain activity within the beta band (19–24 Hz). These neural signatures involved areas which are engaged in sensorimotor integrative processes (secondary somatosensory cortex (SII) and right temporoparietal junction). Altered early and late sensory processes may result from the increase pressure on the mechanoreceptors of the foot sole and not from postural instability per se. Indeed, postural instability with normal weight condition did not lead to SEP changes. PMID:27445758

  11. Vestibular evoked myogenic potentials are heavily dependent on type I hair cell activity of the saccular macula in guinea pigs.

    Science.gov (United States)

    Lue, June-Horng; Day, An-Shiou; Cheng, Po-Wen; Young, Yi-Ho

    2009-01-01

    This study applied the vestibular evoked myogenic potential (VEMP) test to guinea pigs coupled with electronic microscopic examination to determine whether VEMPs are dependent on type I or II hair cell activity of the saccular macula. An amount of 0.05 ml of gentamicin (40 mg/ml) was injected directly overlaying, but not through, the round window membrane of the left ear in guinea pigs.One week after surgery, auditory brainstem response test revealed normal responses in 12 animals (80%), and elevated thresholds in 3 animals (20%). The VEMP test using click stimulation showed absent responses in all 15 animals (100%). Another 6 gentamicin-treated animals underwent the VEMP test using galvanic stimulation and all 6 also displayed absent responses. Ultrathin sections of the saccular macula in the gentamicin-treated ears displayed morphologic alterations in type I or II hair cells, including shrinkage and/or vacuolization in the cytoplasm, increased electron density of the cytoplasm and nuclear chromatin, and cellular lucency. However, extrusion degeneration was rare and only present in type II hair cells. Quantitative analysis demonstrated that the histological density of intact type I hair cells was 1.1 +/- 1.2/4000 microm(2) in the gentamicin-treated ears, showing significantly less than that in control ears (4.5 +/- 1.8/4000 microm(2)). However, no significant difference was observed in the densities of intact type II hair cells and supporting cells between treated and control ears. Furthermore, the calyx terminals surrounding the damaged type I hair cells were swollen and disrupted, while the button afferents contacting the damaged type II hair cells were not obviously deformed. Based on the above results, we therefore conclude that VEMPs are heavily dependent on type I hair cell activity of the saccular macula in guinea pigs.

  12. Membrane, action, and oscillatory potentials in simulated protocells

    Science.gov (United States)

    Przybylski, Aleksander T.; Stratten, Wilford P.; Syren, Robert M.; Fox, Sidney W.

    1982-12-01

    Electrical membrane potentials, oscillations, and action potentials are observed in proteinoid microspheres impaled with (3 M KCl) microelectrodes. Although effects are of greater magnitude when the vesicles contain glycerol and natural or synthetic lecithin, the results in the purely synthetic thermal protein structures are substantial, attaining 20 mV amplitude in some cases. The results add the property of electrical potential to the other known properties of proteinoid microspheres, in their role as models for protocells.

  13. Membrane, action, and oscillatory potentials in simulated protocells

    Science.gov (United States)

    Syren, R. M.; Fox, S. W.; Przybylski, A. T.; Stratten, W. P.

    1982-01-01

    Electrical membrane potentials, oscillations, and action potentials are observed in proteinoid microspheres impaled with (3 M KCl) microelectrodes. Although effects are of greater magnitude when the vesicles contain glycerol and natural or synthetic lecithin, the results in the purely synthetic thermal protein structures are substantial, attaining 20 mV amplitude in some cases. The results add the property of electrical potential to the other known properties of proteinoid microspheres, in their role as models for protocells.

  14. Theophylline-induced potentiation of the antinociceptive action of baclofen.

    OpenAIRE

    Sawynok, J

    1983-01-01

    1--Theophylline (35, 50 mg/kg) potentiated the antinociceptive action of intraperitoneally administered baclofen in the tail flick and hot plate tests. Potentiation was most marked when the pretreatment time was 1 h, but some potentiation was still apparent following a 2 h pretreatment. 2--Theophylline alone (50 mg/kg) produced only slight alterations in reaction latency in the two tests. 3--When baclofen was applied directly into the spinal subarachnoid space, a 1 h pretreatment with theophy...

  15. The Analgesic Effect of Oxytocin in Humans: A Double-Blind, Placebo-Controlled Cross-Over Study Using Laser-Evoked Potentials.

    Science.gov (United States)

    Paloyelis, Y; Krahé, C; Maltezos, S; Williams, S C; Howard, M A; Fotopoulou, A

    2016-04-01

    Oxytocin is a neuropeptide regulating social-affiliative and reproductive behaviour in mammals. Despite robust preclinical evidence for the antinociceptive effects and mechanisms of action of exogenous oxytocin, human studies have produced mixed results regarding the analgesic role of oxytocin and are yet to show a specific modulation of neural processes involved in pain perception. In the present study, we investigated the analgesic effects of 40 IU of intranasal oxytocin in 13 healthy male volunteers using a double-blind, placebo-controlled, cross-over design and brief radiant heat pulses generated by an infrared laser that selectively activate Aδ- and C-fibre nerve endings in the epidermis, at the same time as recording the ensuing laser-evoked potentials (LEPs). We predicted that oxytocin would reduce subjective pain ratings and attenuate the amplitude of the N1, N2 and P2 components. We observed that oxytocin attenuated perceived pain intensity and the local peak amplitude of the N1 and N2 (but not of P2) LEPs, and increased the latency of the N2 component. Importantly, for the first time, the present study reports an association between the analgesic effect of oxytocin (reduction in subjective pain ratings) and the oxytocin-induced modulation of cortical activity after noxious stimulation (attenuation of the N2 LEP). These effects indicate that oxytocin modulates neural processes contributing to pain perception. The present study reports preliminary evidence that is consistent with electrophysiological studies in rodents showing that oxytocin specifically modulates Aδ/C-fibre nociceptive afferent signalling at the spinal level and provides further specificity to evidence obtained in humans indicating that oxytocin may be modulating pain experience by modulating activity in the cortical areas involved in pain processing. PMID:26660859

  16. The mode of action of quinidine on isolated rabbit atria interpreted from intracellular potential records.

    Science.gov (United States)

    VAUGHAN WILLIAMS, E M

    1958-09-01

    An attempt has been made to show why quinidine, which has long been known not to lengthen the duration of the cardiac action potential, measured with external electrodes, and also not to lengthen, and sometimes to shorten, the absolute refractory period, nevertheless reduces the maximum frequency at which atria can respond to a stimulus. Simultaneous measurements have been made in electrically driven isolated rabbit atria of contractions, conduction velocity and intracellular potentials before and during exposure to a wide range of concentrations of quinidine sulphate. The resting potential remained undiminished, in contrast to the effect of quinidine on Purkinje fibres. In the therapeutic range of doses, up to 10 mg./l., the half-time for repolarization was either shortened or unchanged, thus providing an explanation for the failure of quinidine to prolong the absolute refractory period. In contrast, even at low concentrations of quinidine, conduction velocity and the rate of rise of the action potential were greatly slowed, and the height of the overshoot was reduced. The terminal phase of the action potential was prolonged. It is known that the rate of rise of the action potential is a function of the level of repolarization at which an impulse takes off (the more negative the take-off point, the faster the rate of rise). Normally, a stimulus introduced when repolarization has proceeded to 2/3 of the resting potential evokes a response with a rate of rise fast enough for propagation, so that the duration of the terminal 1/3 of the phase of repolarization has no influence upon the length of the effective refractory period. In the presence of quinidine, however, the rate of rise itself was directly reduced, thus repolarization had to proceed further before the critical take-off point was reached at which the rate of rise was fast enough for propagation, and the duration of the terminal phase of repolarization thus became significant. It has been concluded that

  17. A steady-state visual evoked potential approach to individual face perception: Effect of inversion, contrast-reversal and temporal dynamics

    OpenAIRE

    Rossion, Bruno; Prieto, Esther Alonso; Boremanse, Adriano; Kuefner, Dana; Van Belle, Goedele

    2012-01-01

    Presentation of a face stimulus for several seconds at a periodic frequency rate leads to a right occipito-temporal evoked steady-state visual potential (SSVEP) confined to the stimulation frequency band. According to recent evidence (Rossion and Boremanse, 2011), this face-related SSVEP is largely reduced in amplitude when the exact same face is repeated at every stimulation cycle as compared to the presentation of different individual faces. Here this SSVEP individual face repetition effect...

  18. Combination of blood oxygen level–dependent functional magnetic resonance imaging and visual evoked potential recordings for abnormal visual cortex in two types of amblyopia

    OpenAIRE

    Wang, Xinmei; Cui, Dongmei; Zheng, Ling; Yang, Xiao; Yang, Hui; Zeng, Junwen

    2012-01-01

    Purpose To elucidate the different neuromechanisms of subjects with strabismic and anisometropic amblyopia compared with normal vision subjects using blood oxygen level–dependent functional magnetic resonance imaging (BOLD-fMRI) and pattern-reversal visual evoked potential (PR-VEP). Methods Fifty-three subjects, age range seven to 12 years, diagnosed with strabismic amblyopia (17 cases), anisometropic amblyopia (20 cases), and normal vision (16 cases), were examined using the BOLD-fMRI and PR...

  19. Brain responses evoked by high-frequency repetitive transcranial magnetic stimulation: an event-related potential study

    NARCIS (Netherlands)

    M. Hamidi; H.A. Slagter; G. Tononi; B.R. Postle

    2010-01-01

    Background Many recent studies have used repetitive transcranial magnetic stimulation (rTMS) to study brain-behavior relationships. However, the pulse-to-pulse neural effects of rapid delivery of multiple TMS pulses are unknown largely because of TMS-evoked electrical artifacts limiting recording of

  20. Sensorimotor and cognitive involvement of the beta-gamma oscillation in the frontal N30 component of somatosensory evoked potentials.

    Science.gov (United States)

    Cebolla, A M; Cheron, G

    2015-12-01

    The most consistent negative cortical component of somatosensory evoked potentials (SEPs), namely the frontal N30, can be considered more multidimensional than a strict item of standard somatosensory investigation, dedicated to tracking the afferent volley from the peripheral sensory nerve potentials to the primary somatosensory cortex. In this review, we revisited its classical sensorimotor implication within the framework of the recent oscillatory model of ongoing electroencephalogram (EEG) rhythms. Recently, the N30 component was demonstrated to be related to an increase in the power of beta-gamma EEG oscillation and a phase reorganization of the ongoing EEG oscillations (phase locking) in this frequency band. Thanks to high density EEG recordings and the inverse modeling method (swLORETA), it was shown that different overlapping areas of the motor and premotor cortex are specifically involved in generating the N30 in the form of a beta gamma oscillatory phase locking and power increase. This oscillatory approach has allowed a re-investigation of the movement gating behavior of the N30. It was demonstrated that the concomitant execution of finger movements by a stimulated hand impinges the temporal concentration of the ongoing beta/gamma EEG oscillations and abolished the N30 component. It was hypothesized that the involvement of neuronal populations in both the sensorimotor cortex and other related areas were unable to respond to the phasic sensory activation so could not phase-lock their oscillatory signals to the external sensory input during the movement. In this case, the actual movement has primacy over the artificial somatosensory input. The contribution of the ongoing oscillatory activity in the N30 emergence calls for a reappraisal of fundamental and clinical interpretations of the frontal N30 component. An absent or reduced amplitude of the N30 can now be viewed not only as a deficit in the activation of the somatosensory synaptic network in response

  1. Sedation and anesthesia of hatchling leatherback sea turtles (Dermochelys coriacea) for auditory evoked potential measurement in air and in water.

    Science.gov (United States)

    Harms, Craig A; Piniak, Wendy E D; Eckert, Scott A; Stringer, Elizabeth M

    2014-03-01

    Sedation or anesthesia of hatchling leatherback sea turtles was employed to acquire auditory evoked potential (AEP) measurements in air and in water to assess their hearing sensitivity in relation to potential consequences from anthropogenic noise. To reduce artifacts in AEP collection caused by muscle movement, hatchlings were sedated with midazolam 2 or 3 mg/kg i.v. for in-air (n = 7) or in-water (n = 11) AEP measurements; hatchlings (n = 5) were anesthetized with ketamine 6 mg/kg and dexmedetomidine 30 microg/kg i.v. reversed with atipamezole 300 microg/kg, half i.m. and half i.v. for in-air AEP measurements. Midazolam-sedated turtles were also physically restrained with a light elastic wrap. For in-water AEP measurements, sedated turtles were brought to the surface every 45-60 sec, or whenever they showed intention signs for breathing, and not submerged again until they took a breath. Postprocedure temperature-corrected venous blood pH, pCO2, pO2, and HCO3- did not differ among groups, although for the midazolam-sedated in-water group, pCO2 trended lower, and in the ketamine-dexmedetomidine anesthetized group there was one turtle considered clinically acidotic (temperature-corrected pH = 7.117). Venous blood lactate was greater for hatchlings recently emerged from the nest than for turtles sedated with midazolam in air, with the other two groups falling intermediate between, but not differing significantly from the high and low lactate groups. Disruptive movements were less frequent with anesthesia than with sedation in the in-air group. Both sedation with midazolam and anesthesia with ketamine-dexmedetomidine were successful for allowing AEP measurements in hatchling leatherback sea turtles. Sedation allowed the turtle to protect its airway voluntarily while limiting flipper movement. Midazolam or ketamine-dexmedetomidine (and reversal with atipamezole) would be useful for other procedures requiring minor or major restraint in leatherback sea turtle hatchlings

  2. Action prediction based on anticipatory brain potentials during simulated driving

    Science.gov (United States)

    Khaliliardali, Zahra; Chavarriaga, Ricardo; Gheorghe, Lucian Andrei; Millán, José del R.

    2015-12-01

    Objective. The ability of an automobile to infer the driver’s upcoming actions directly from neural signals could enrich the interaction of the car with its driver. Intelligent vehicles fitted with an on-board brain-computer interface able to decode the driver’s intentions can use this information to improve the driving experience. In this study we investigate the neural signatures of anticipation of specific actions, namely braking and accelerating. Approach. We investigated anticipatory slow cortical potentials in electroencephalogram recorded from 18 healthy participants in a driving simulator using a variant of the contingent negative variation (CNV) paradigm with Go and No-go conditions: count-down numbers followed by ‘Start’/‘Stop’ cue. We report decoding performance before the action onset using a quadratic discriminant analysis classifier based on temporal features. Main results. (i) Despite the visual and driving related cognitive distractions, we show the presence of anticipatory event related potentials locked to the stimuli onset similar to the widely reported CNV signal (with an average peak value of -8 μV at electrode Cz). (ii) We demonstrate the discrimination between cases requiring to perform an action upon imperative subsequent stimulus (Go condition, e.g. a ‘Red’ traffic light) versus events that do not require such action (No-go condition; e.g. a ‘Yellow’ light); with an average single trial classification performance of 0.83 ± 0.13 for braking and 0.79 ± 0.12 for accelerating (area under the curve). (iii) We show that the centro-medial anticipatory potentials are observed as early as 320 ± 200 ms before the action with a detection rate of 0.77 ± 0.12 in offline analysis. Significance. We show for the first time the feasibility of predicting the driver’s intention through decoding anticipatory related potentials during simulated car driving with high recognition rates.

  3. Propagation of Action Potentials: An Active Participation Exercise.

    Science.gov (United States)

    Felsten, Gary

    1998-01-01

    Describes an active participation exercise that demonstrates the propagation of action potentials (the ability to transmit information through the neural network, dependent upon chemical interactions in the brain). Students assume the structure and function of the network by lining up around the room and communicating through hand signals and…

  4. Uncertainty propagation in nerve impulses through the action potential mechanism

    NARCIS (Netherlands)

    Torres Valderrama, A.; Witteveen, J.A.S.; Navarro Jimenez, M.I.; Blom, J.G.

    2015-01-01

    We investigate the propagation of probabilistic uncertainty through the action potential mechanism in nerve cells. Using the Hodgkin-Huxley (H-H) model and Stochastic Collocation on Sparse Grids, we obtain an accurate probabilistic interpretation of the deterministic dynamics of the transmembrane po

  5. Compound muscle action potentials in newborn infants with spina bifida.

    NARCIS (Netherlands)

    Geerdink, N.; Pasman, J.W.; Rotteveel, J.J.; Roeleveld, N.; Mullaart, R.A.

    2008-01-01

    The aim of this study was to investigate the relationship between compound muscle action potentials (CMAPs) and neurological impairment in newborn infants with spina bifida. Thirty-one newborn infants (17 males, 14 females, mean gestational age 39 wks [SD 2]; mean birthweight 3336 g [SD 496]) with s

  6. Regulation of action potential waveforms by axonal GABAA receptors in cortical pyramidal neurons.

    Directory of Open Access Journals (Sweden)

    Yang Xia

    Full Text Available GABAA receptors distributed in somatodendritic compartments play critical roles in regulating neuronal activities, including spike timing and firing pattern; however, the properties and functions of GABAA receptors at the axon are still poorly understood. By recording from the cut end (bleb of the main axon trunk of layer -5 pyramidal neurons in prefrontal cortical slices, we found that currents evoked by GABA iontophoresis could be blocked by picrotoxin, indicating the expression of GABAA receptors in axons. Stationary noise analysis revealed that single-channel properties of axonal GABAA receptors were similar to those of somatic receptors. Perforated patch recording with gramicidin revealed that the reversal potential of the GABA response was more negative than the resting membrane potential at the axon trunk, suggesting that GABA may hyperpolarize the axonal membrane potential. Further experiments demonstrated that the activation of axonal GABAA receptors regulated the amplitude and duration of action potentials (APs and decreased the AP-induced Ca2+ transients at the axon. Together, our results indicate that the waveform of axonal APs and the downstream Ca2+ signals are modulated by axonal GABAA receptors.

  7. Analysis on the training effect of criteria and practical guidance for determination of brain death: evoked potentials

    Directory of Open Access Journals (Sweden)

    Yan ZHANG

    2015-12-01

    Full Text Available Objective To analyze the training results of short-latency somatosensory-evoked potential (SLSEP for brain death determination and to improve the training program. Methods A total of 101 trainees received theoretical training, simulation skills training, bedside skills training and test analysis for SLSEP in brain death determination. The composition of trainees was analyzed and the error rates of 6 knowledge points were calculated. Univariate and multivariate backward Logistic regression analyses were used to analyze the influence of factors including sex, age, specialty, professional category, professional qualification and hospital level, on the error rates. Results Among them, trainees of 30-49 years old occupied 76.24% (77/101, most of them were from third grade, grade A hospitals (98.02%, 99/101, and 78 trainees (77.23% were from Department of Neurology. There were 82 clinicians (81.19%, 31 (30.69% had senior certificate and 42 (41.58% had intermediate certificate. Total error rate of 6 knowledge points was 4.50% (91/2020. Of the 6 knowledge points, the error rate of pitfalls was the highest (9.41%, 19/202, followed by result determination (5.94% , 12/202, recording techniques (4.75% , 24/505, procedures (3.96%, 32/808, sequence of confirmatory tests (1.98%, 2/101 and environmental conditions (0.99%, 2/202. Univariate and multivariate Logistic regression analyses showed that age (OR = 1.566, 95% CI: 1.116-2.197; P = 0.009 and professional qualification (OR = 1.669, 95% CI: 1.163-2.397; P = 0.005 were independent risk factors associated with high error rates. Conclusions The differences between brain death determination and routine check of SLSEP should be paid more attention to improve the quality of determination for brain death by SLSEP.  DOI: 10.3969/j.issn.1672-6731.2015.12.007

  8. Sodium and potassium conductance changes during a membrane action potential.

    Science.gov (United States)

    Bezanilla, F; Rojas, E; Taylor, R E

    1970-12-01

    1. A method for turning a membrane potential control system on and off in less than 10 musec is described. This method was used to record membrane currents in perfused giant axons from Dosidicus gigas and Loligo forbesi after turning on the voltage clamp system at various times during the course of a membrane action potential.2. The membrane current measured just after the capacity charging transient was found to have an almost linear relation to the controlled membrane potential.3. The total membrane conductance taken from these current-voltage curves was found to have a time course during the action potential similar to that found by Cole & Curtis (1939).4. The instantaneous current voltage curves were linear enough to make it possible to obtain a good estimate of the individual sodium and potassium channel conductances, either algebraically or by clamping to the sodium, or potassium, reversal potentials. Good general agreement was obtained with the predictions of the Hodgkin-Huxley equations.5. We consider these results to constitute the first direct experimental demonstration of the conductance changes to sodium and potassium during the course of an action potential. PMID:5505231

  9. Action potential initiation in the hodgkin-huxley model.

    Directory of Open Access Journals (Sweden)

    Lucy J Colwell

    2009-01-01

    Full Text Available A recent paper of B. Naundorf et al. described an intriguing negative correlation between variability of the onset potential at which an action potential occurs (the onset span and the rapidity of action potential initiation (the onset rapidity. This correlation was demonstrated in numerical simulations of the Hodgkin-Huxley model. Due to this antagonism, it is argued that Hodgkin-Huxley-type models are unable to explain action potential initiation observed in cortical neurons in vivo or in vitro. Here we apply a method from theoretical physics to derive an analytical characterization of this problem. We analytically compute the probability distribution of onset potentials and analytically derive the inverse relationship between onset span and onset rapidity. We find that the relationship between onset span and onset rapidity depends on the level of synaptic background activity. Hence we are able to elucidate the regions of parameter space for which the Hodgkin-Huxley model is able to accurately describe the behavior of this system.

  10. Compound sensory action potential in normal and pathological human nerves

    DEFF Research Database (Denmark)

    Krarup, Christian

    2004-01-01

    The compound sensory nerve action potential (SNAP) is the result of phase summation and cancellation of single fiber potentials (SFAPs) with amplitudes that depend on fiber diameter, and the amplitude and shape of the SNAP is determined by the distribution of fiber diameters. Conduction velocities...... at different conduction distances are determined by summation of SFAPs of varying fiber diameters, and differ in this respect, also, from the compound muscle action potential (CMAP) for which conduction velocities are determined by the very fastest fibers in the nerve. The effect and extent of temporal......, with fiber loss or increased conduction velocity variability changes of the SNAP may be smaller than expected from normal nerve. The biophysical characteristics of sensory and motor fibers differ, and this may to some extent determine divergent pathophysiological changes in sensory and motor fibers...

  11. Activation of serotonin 2A receptors underlies the psilocybin-induced effects on α oscillations, N170 visual-evoked potentials, and visual hallucinations.

    Science.gov (United States)

    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 μg/kg vs placebo) on both α 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 α power values, thus precluding a subsequent stimulus-induced α 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 α 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.

  12. Normal values of flash visual evoked potentials in rabbits:Differences between the sexes and the eyes

    Institute of Scientific and Technical Information of China (English)

    Bo Bu; Dingbiao Zhou; Bainan Xu; Xinguang Yu; Yuanzheng Zhang

    2006-01-01

    BACKGROUND: The wave form, latency and wave amplitude of visual evoked potentials (VEP) are obviously affected by the stimulative parameters, physiological status of the subjects and anesthetics, thus there are greater normal variations and individual differences. The features of flash VEP (F-VEP) are to be observed.OBJECTIVE: To observe and compare the differences of F-VEP latencies and wave amplitudes between eyes in rabbits, and investigate the correlation with sex and the side of eyes.DESIGN: A comparative animal experiment.SETTING: Department of Neurosurgery, General Hospital of Chinese PLA.MATERIALS: The experiment was carried out in the neurophysiological laboratory of the Institute of Neurosciences, General Hospital of Chinese PLA from September 2004 to February 2005. Thirty big-ear rabbits of clean degree, 15 males and 15 females, weighing 2.0-2.5 kg, were provided by the animal center of the General Hospital of Chinese PLA.METHODS: Viking-IV perioperative monitor and flash stimulator for special use were applied. The rabbits were anesthetized with intramuscular injection of compound ketamine. The recording electrode was placed at 3 mm anterior to exoccipital tuberosity (onion, Oz), and the reference electrode was placed at the ear edge of the same side. The stimulative frequency was 1.9 Hz, and the amplifier was 50 μV; The range of wave filter was 5 Hz for high pass and 100 Hz for Iow pass; The average overlapping was 200 times, and the analytical time was 250 ms.MAIN OUTCOME MEASURES: Comparison of F-VEP wave forms; F-VEP latencies and wave amplitudes.RESULTS: All the 30 rabbits were involved in the analysis of results. ① Comparison of F-VEP wave forms in rabbits: The F-VEP waves mainly manifested aspositive-negative-positive (PNP). The F-VEP manifestations to light stimulations were extremely similar between left and right eyes, and the wave amplitudes of both eyes were obviously increased. ② Determinations of F-VEP latencies and wave amplitudes

  13. Visual acuity evaluated by pattern-reversal visual-evoked potential is affected by check size/visual angle

    Institute of Scientific and Technical Information of China (English)

    Xiping Chen; Qianqian Li; Xiaoqin Liu; Li Yang; Wentao Xia; Luyang Tao

    2012-01-01

    Objective To systemically explore the range of visual angles that affect visual acuity,and to establish the relationship between the P 1 component (peak latency ~100 ms) of the pattern-reversal visual-evoked potential (PRVEP) and the visual acuity at particular visual angles.Methods Two hundred and ten volunteers were divided into seven groups,according to visual acuity as assessed by the standard logarithmic visual acuity chart (SLD-II).For each group,the PRVEP components were elicited in response to visual angle presentations at 8°,4°,2°,1 °/60′,30′,15′,and 7.5′,in the whiteblack chess-board reversal mode with a contrast level of 100% at a frequency of 2 Hz.Visual stimuli were presented monocularly,and 200 presentations were averaged for each block of trials.The early and stable component P1 was recorded at the mid-line of the occipital region (Oz) and analyzed with SPSS 13.00.Results (1) Oz had the maximum P1 amplitude;there was no significant difference between genders or for interocular comparison in normal controls and subjects with optic myopia.(2) The P1 latency decreased slowly below 30′,then increased rapidly.The P1 amplitude initially increased with check size,and was maximal at ~1° and ~30′.(3) The P1 latency in the group with visual acuity ≤0.2 was significantly different at 8°,15′ and 7.5′,while the amplitude differed at all visual angles,compared with the group with normal vision.Diferences in P1 for the groups with 0.5 and 0.6 acuity were only present at visual angles <1°.(4) Regression analysis showed that the P 1 latency and amplitude were associated with visual acuity over the full range of visual angles.There was a moderate correlation at visual angles <30′.Regression equations were calculated for the P1 components and visual acuity,based on visual angle.Conclusion (1) Visual angle should be taken into consideration when exploring the function of the visual pathway,especially visual acuity.A visual angle

  14. Effects of ligustrazine on somatosensory evoked potential in normal rabbits and rabbits with cerebral ischemia-reperfusion injury

    Institute of Scientific and Technical Information of China (English)

    Deshan Liu; Shuli Wang; Yuanyuan Hao

    2006-01-01

    BACKGROUND: Somatosensory evoked potential (SEP) has become a method with higher sensitivity and specificity than electroencephalogram in detecting the brain function and the region, range and degree of ischemia. However, the effects of ligustrazine on SEP is still not clear.OBJECTIVE: To study the protective effects of ligustrazini injection on cerebral ischemia-reperfusion injury.DESIGN: Auto-control study, random grouping.SETTING: Qilu Hospital of Shandong University.MATERIALS: The experiment was completed in the Cerebral Functional Room of Qilu Hospital Affiliated to Shandong University from March 2002 to June 2004. A totally of 24 healthy Harbin rabbits were randomly divided into blank control group (n=8), model control group (n=8) and ligustrazine treatment group (n=8).Hydrochloric ligustrazine injection, 40 mg/2 mL each ampoule, was provided by the Third Pharmaceutical Factory of Beijing (certification: 93035236273). The main component was hydrochloric ligustrazine and the chemical name was 2, 3, 5, 6-tetramethyl pyrazine hydrochloride.METHODS: ① Modeling method: The bilateral common carotid artery ligation was adopted to make the model. ② Index of cerebral functional lesion evaluated with SEP during ischemia-reperfusion: DISA 2000C neuromyoeletrometer provided by Dantec Electronics Ltd, Denmark was used to detect SEP. ③ Interventional process: Blank control group: The latencies and amplitudes of SEP were measured before injection with 1.5 mg/kg ligustrazine and at the points of 15 minutes, 20 minutes, 30 minutes, 60 minutes, 90 minutes and 120 minutes after injection. Ligustrazine treatment group: Rabbits were injected with 1.5 mg/kg ligustrazine, and those of model control group were injected the same volume of saline. Thirty minutes later, the bilateral common carotid artery of the rabbits all had been ligated for 30 minutes, and then reperfused for 120 minutes. The latencies and amplitudes of SEP were measured before injection, before ligation, at

  15. Use of the novel contact heat evoked potential stimulator (CHEPS) for the assessment of small fibre neuropathy: correlations with skin flare responses and intra-epidermal nerve fibre counts

    OpenAIRE

    Chizh Boris A; Misra V Peter; Roberts Katherine M; Facer Paul; Atherton Duncan D; Bountra Chas; Anand Praveen

    2007-01-01

    Abstract Background The Contact Heat Evoked Potential Stimulator (CHEPS) rapidly stimulates cutaneous small nerve fibres, and resulting evoked potentials can be recorded from the scalp. We have studied patients with symptoms of sensory neuropathy and controls using CHEPS, and validated the findings using other objective measures of small nerve fibres i.e. the histamine-induced skin flare response and intra-epidermal fibres (IEF), and also quantitative sensory testing (QST), a subjective measu...

  16. Warm body temperature facilitates energy efficient cortical action potentials.

    Directory of Open Access Journals (Sweden)

    Yuguo Yu

    Full Text Available The energy efficiency of neural signal transmission is important not only as a limiting factor in brain architecture, but it also influences the interpretation of functional brain imaging signals. Action potential generation in mammalian, versus invertebrate, axons is remarkably energy efficient. Here we demonstrate that this increase in energy efficiency is due largely to a warmer body temperature. Increases in temperature result in an exponential increase in energy efficiency for single action potentials by increasing the rate of Na(+ channel inactivation, resulting in a marked reduction in overlap of the inward Na(+, and outward K(+, currents and a shortening of action potential duration. This increase in single spike efficiency is, however, counterbalanced by a temperature-dependent decrease in the amplitude and duration of the spike afterhyperpolarization, resulting in a nonlinear increase in the spike firing rate, particularly at temperatures above approximately 35°C. Interestingly, the total energy cost, as measured by the multiplication of total Na(+ entry per spike and average firing rate in response to a constant input, reaches a global minimum between 37-42°C. Our results indicate that increases in temperature result in an unexpected increase in energy efficiency, especially near normal body temperature, thus allowing the brain to utilize an energy efficient neural code.

  17. Multimodal evoked potentials and the ovarian cycle in young ovulating women Potenciais evocados nas diferentes fases do ciclo menstrual da mulher

    Directory of Open Access Journals (Sweden)

    LUIZ ANTONIO DE LIMA RESENDE

    2000-06-01

    Full Text Available There is controversy over how hormonal conditions influence cerebral physiology. We studied pattern-shift visual evoked potentials (PS-VEP, brain stem auditory evoked potentials (BAEP and short-latency somatosensory evoked potentials (SSEV in 20 female volunteers at different phases of the menstrual cycle (estrogen phase, ovulatory day and progesterone phase. Statistical analysis showed decreased latencies for P100 (PS-VEP, N19 and P22 (SSEV waves in the progesterone phase compared with the estrogen phase. There was no significant difference between the estrogen and the ovulation day values. Comparing the three above stages, there were no significant differences in the brainstem auditory evoked potentials. The reduction of the latencies of the potentials generated in multisynaptic circuits provides the first consistent neurophysiological basis for a tentative comprehension of human pre-menstrual syndrome.Há controvérsias sobre como variações hormonais do ciclo menstrual da mulher influenciam a neurofisiologia cerebral. Estudamos potenciais evocados de curta latência, visuais, auditivos e sômato-sensoriais, em 20 mulheres voluntárias normais, nas diferentes fases do ciclo menstrual (fase estrogênica, fase ovulatória, fase progestacional. Comparação entre fase estrogênica e ovulatória mostrou resultados similares. Ondas I, III, V dos potenciais evocados auditivos não apresentaram diferenças estatisticamente significativas entre as três fases do ciclo. Análise estatística dos resultados mostrou diminuição significativa das latências das ondas P100, N19 e P22 obtidas na fase progestacional, comparadas com aquelas obtidas na fase estrogênica. Como estas ondas são geradas em circuitos multissinápticos, tal redução de latências, na fase progestacional, fornece a primeira base neurofisiológica consistente para tentativa de compreensão da síndrome pré-menstrual da mulher.

  18. Implementing participatory action research in Lithuania: potential and challenges

    Directory of Open Access Journals (Sweden)

    Gabija Jarašiūnaitė

    2015-12-01

    Full Text Available Participatory action research is a quite new approach to research in Lithuania. The aim of an article was to disscuss the potential and challenges of participatory action research while implementing it in Lithuanian organizations. The qualitative approach was chosen for the study using the method of Focus groups. 20 researchers from social and biomedicine sciences from six institutions of High education in Lithuania participated in the study. The results of the study showed that participatory action reasearch is seen as an approach with many possibilities because of a wide range of used methods, constant interactions with research participants and the lenght of the research process. Researchers value the possibility to access organization at the begining, during research process and evaluate the effectiveness of the changes after the process. The research challenges are associated with the competence of a researcher including his/her sensitivity during process, ability to involve active participation of organization members in the ongoing process by creating safe and trusting environment. Some specific challenges associated with Lithuanian organizations are organizations‘ tiredness of researches and lack of faith of the benefits of researches because of some previous experiences. Keywords: Participatory Action Research, Organization, Lithuania.

  19. [Effect of the novel dipeptide nootropic agent noopept and its metabolite cyclo-L-prolylglycine on the transcallosal evoked potential in the rat brain].

    Science.gov (United States)

    Molodavkin, G M; Borlikova, G G; Voronina, T A; Gudasheva, T A; Ostrovskaia, R U; Tushmalova, N A; Seredenin, S B

    2002-01-01

    The effect of new nootropic dipeptides--noopept (N-phenylacetyl-L-prolylglycine, GVS-111) and its metabolite (cyclo-L-prolylglycine)--and a standard nootrope piracetam on the transcallosal evoked potential (TEP) in rat brain was studied. In the dose range from 150 to 300 mg/kg, piracetam increased the TEP amplitude, which exhibited a maximum after 1.5-2 h and then gradually decreased. Both noopept and cyclo-L-prolylglycine also increased the TEP amplitude, which attained a plateau and retained this level over the entire observation time (above 3.5 h). All the nootropes studied increased both components of the evoked potential. Piracetam and cyclo-L-prolylglycine led to an approximately equal increase in both waves, while noopept induced a somewhat greater increase in the negative TEP wave amplitude. It is suggested that the positive effect of noopept and cyclo-L-prolylglycine upon the interhemispheric signal transfer (indicated by the improved transcallosal response) can be considered as a potential neurophysiological basis for a positive drug influence on the behavioral level. PMID:12109288

  20. 诱发电位监测在脊柱外科手术中的应用%Application of evoked potential monitoring in spinal surgery

    Institute of Scientific and Technical Information of China (English)

    茅磊; 王汉东; 吴伟; 张治元

    2013-01-01

    目的 术中电生理监测已越来越多的应用于脊柱外科手术.文中拟探讨体感诱发电位(somatosensory evoked potential,SEP)、运动诱发电位(motor evoked potential,MEP)在脊柱外科手术中的应用价值.方法 共监测10例脊柱脊髓病变手术患者,3例术中采用SEP监测,7例术中采用SEP联合MEP监测.结果 SEP均顺利诱发并予以记录,而MEP只有3例顺利诱发并予以记录.有2例患者术中SEP的波幅较预警基准电位下降,经调整手术操作方式或停止操作后恢复;另有1例患者术后SEP的波幅升高,术后证实患者的症状较术前改善.记录到SEP的3例患者,MEP波幅和潜伏期与预警基准电位比较均无明显变化.结论脊柱外科术中行诱发电位监测,特别是SEP与MEP联合监测,能有效降低脊髓机械性损伤,保护神经功能,提高病变的切除率,增加手术的安全性,增强术者的信心.%Objective Intraoperative electrophysiological monitoring is gaining a wider application in spinal surgery. The present article is to explore the application value of somatosensory evoked potential ( SEP ) and motor evoked potential ( MEP ) in spinal surgery. Methods We employed both SEP and MEP for dynamic monitoring of 7 cases of spinal surgery, and adopted SEP alone for another 3. Results SEP was successfully induced and recorded in all the cases, while MEP only in 3 cases. Compared with preop-erative forewarning potential, the wave amplitude of SEP was decreased during intraoperative monitoring in 2 cases, but restored to normal after the operation was stopped or the surgical methods adjusted. One case showed obviously improved symptoms after surgery though with an increased wave amplitude of SEP during intraoperative monitoring. No significant changes were observed in either amplitude or latency of the wave in the 3 cases with MEP recorded. Conclusion Evoked potential monitoring, especially with combined SEP and MEP during spinal surgery, can effectively

  1. Gating of the vertex somatosensory and auditory evoked potential P50 and the correlation to skin conductance orienting response in healthy men.

    Science.gov (United States)

    Arnfred, S M; Eder, D N; Hemmingsen, R P; Glenthøj, B Y; Chen, A C

    2001-04-15

    A defect in auditory evoked potential (AEP) P50 gating supports the theory of information-processing deficits in schizophrenia. The relationship between gating of the mid-latency evoked potentials (EP) in the somatosensory and the auditory modalities has not been studied together before. In schizophrenia, we might expect the processing deficits to act on multiple modalities. We have examined the gating of median nerve somatosensory EP (SEP) following paired stimulation identical to the AEP P50 gating paradigm using interstimulus intervals (ISI) of 500, 750 and 1000 ms and the correlation of gating to the skin conductance orienting response (SCOR) in 20 healthy men. We measured mid-latency vertex components (SEP: P50, N65, P85 and N100; AEP: P30, N45, P50 and N80). The gating was most pronounced at ISI 500 ms where the SEP P50 and N100 gating were 0.59 and 0.37, respectively, as compared to a gating of 0.61 in P30, 0.33 in P50 and 0.45 in N80 in the AEP. Repetition effects in the two modalities were not correlated. AEP P50 gating was correlated to skin conductance level (SCL). The combination of recording repetition effects on the mid-latency EP in two modalities could provide a method for investigating if deficits of information processing in schizophrenia are cross-modal.

  2. Intraoperative facial motor evoked potentials monitoring with transcranial electrical stimulation for preservation of facial nerve function in patients with large acoustic neuroma

    Institute of Scientific and Technical Information of China (English)

    LIU Bai-yun; TIAN Yong-ji; LIU Wen; LIU Shu-ling; QIAO Hui; ZHANG Jun-ting; JIA Gui-jun

    2007-01-01

    Background Although various monitoring techniques have been used routinely in the treatment of the lesions in the skull base, iatrogenic facial paresis or paralysis remains a significant clinical problem. The aim of this study was to investigate the effect of intraoperative facial motor evoked potentials monitoring with transcranial electrical stimulation on preservation of facial nerve function.Method From January to November 2005, 19 patients with large acoustic neuroma were treated using intraoperative facial motor evoked potentials monitoring with transcranial electrical stimulation (TCEMEP) for preservation of facial nerve function. The relationship between the decrease of MEP amplitude after tumor removal and the postoperative function of the facial nerve was analyzed.Results MEP amplitude decreased more than 75% in 11 patients, of which 6 presented significant facial paralysis (H-B grade 3), and 5 had mild facial paralysis (H-B grade 2). In the other 8 patients, whose MEP amplitude decreased less than 75%, 1 experienced significant facial paralysis, 5 had mild facial paralysis, and 2 were normal.Conclusions Intraoperative TCEMEP can be used to predict postoperative function of the facial nerve. The decreased MEP amplitude above 75 % is an alarm point for possible severe facial paralysis.

  3. 窒息新生儿脑干诱发电位的检测价值%The Value of Brainstem Auditory Evoked Potential in Asphyxia Neonatorum

    Institute of Scientific and Technical Information of China (English)

    李秋玲

    2011-01-01

    围生期窒息后可引起听神经通路细胞的缺血/再灌注损伤,从而影响听觉功能.脑干听觉诱发电位可反映脑神经和脑听觉通路不同部位所引起的生物电活动,因其客观、准确、重复性好、无损伤性、受干扰因素少而受到儿科工作者重视.对可能累及到中枢神经系统功能失调及听力障碍的儿科疾病具有早期诊断和判断预后的临床参考价值.%The ischemic reperfusion of injury of nerve cell in auditory pathway can be caued by perinatal asphyxia. And the injury can affect hearing. Brainstem auditory evoked potential can reflect the bioelectric activity of cranial nerves and cerebral auditory pathway. Because it have not only good objectivity, precision and reproducibility , but also it have no damage and few interference factors, brainstem auditory evoked potential was thought highly by pediatrician. It has the clinical reference value of early diagnosis and the judgment of prognosis in pediatrie disease of central dysautonomia and dysacusis.

  4. The afterhyperpolarizing potential following a train of action potentials is suppressed in an acute epilepsy model in the rat Cornu Ammonis 1 area.

    Science.gov (United States)

    Kernig, K; Kirschstein, T; Würdemann, T; Rohde, M; Köhling, R

    2012-01-10

    In hippocampal Cornu Ammonis 1 (CA1) neurons, a prolonged depolarization evokes a train of action potentials followed by a prominent afterhyperpolarizing potential (AHP), which critically dampens neuronal excitability. Because it is not known whether epileptiform activity alters the AHP and whether any alteration of the AHP is independent of inhibition, we acutely induced epileptiform activity by bath application of the GABA(A) receptor blocker gabazine (5 μM) in the rat hippocampal slice preparation and studied its impact on the AHP using intracellular recordings. Following 10 min of gabazine wash-in, slices started to develop spontaneous epileptiform discharges. This disinhibition was accompanied by a significant shift of the resting membrane potential of CA1 neurons to more depolarized values. Prolonged depolarizations (600 ms) elicited a train of action potentials, the number of which was not different between baseline and gabazine treatment. However, the AHP following the train of action potentials was significantly reduced after 20 min of gabazine treatment. When the induction of epileptiform activity was prevented by co-application of 6-cyano-7-nitroquinoxaline-2,3-dione disodium (CNQX, 10 μM) and D-(-)-2-amino-5-phosphonopentanoic acid (D-AP5, 50 μM) to block α-amino-3-hydroxy-5-methylisoxazolepropionate (AMPA) and N-methyl-d-aspartate (NMDA) receptors, respectively, the AHP was preserved despite of GABA(A) receptor inhibition suggesting that the epileptiform activity was required to suppress the AHP. Moreover, the AHP was also preserved when the slices were treated with the protein kinase blockers H-9 (100 μM) and H-89 (1 μM). These results demonstrate that the AHP following a train of action potentials is rapidly suppressed by acutely induced epileptiform activity due to a phosphorylation process-presumably involving protein kinase A.

  5. Flexible graphene transistors for recording cell action potentials

    Science.gov (United States)

    Blaschke, Benno M.; Lottner, Martin; Drieschner, Simon; Bonaccini Calia, Andrea; Stoiber, Karolina; Rousseau, Lionel; Lissourges, Gaëlle; Garrido, Jose A.

    2016-06-01

    Graphene solution-gated field-effect transistors (SGFETs) are a promising platform for the recording of cell action potentials due to the intrinsic high signal amplification of graphene transistors. In addition, graphene technology fulfills important key requirements for in-vivo applications, such as biocompability, mechanical flexibility, as well as ease of high density integration. In this paper we demonstrate the fabrication of flexible arrays of graphene SGFETs on polyimide, a biocompatible polymeric substrate. We investigate the transistor’s transconductance and intrinsic electronic noise which are key parameters for the device sensitivity, confirming that the obtained values are comparable to those of rigid graphene SGFETs. Furthermore, we show that the devices do not degrade during repeated bending and the transconductance, governed by the electronic properties of graphene, is unaffected by bending. After cell culture, we demonstrate the recording of cell action potentials from cardiomyocyte-like cells with a high signal-to-noise ratio that is higher or comparable to competing state of the art technologies. Our results highlight the great capabilities of flexible graphene SGFETs in bioelectronics, providing a solid foundation for in-vivo experiments and, eventually, for graphene-based neuroprosthetics.

  6. The Effect of Short-Term Auditory Training on Speech in Noise Perception and Cortical Auditory Evoked Potentials in Adults with Cochlear Implants.

    Science.gov (United States)

    Barlow, Nathan; Purdy, Suzanne C; Sharma, Mridula; Giles, Ellen; Narne, Vijay

    2016-02-01

    This study investigated whether a short intensive psychophysical auditory training program is associated with speech perception benefits and changes in cortical auditory evoked potentials (CAEPs) in adult cochlear implant (CI) users. Ten adult implant recipients trained approximately 7 hours on psychophysical tasks (Gap-in-Noise Detection, Frequency Discrimination, Spectral Rippled Noise [SRN], Iterated Rippled Noise, Temporal Modulation). Speech performance was assessed before and after training using Lexical Neighborhood Test (LNT) words in quiet and in eight-speaker babble. CAEPs evoked by a natural speech stimulus /baba/ with varying syllable stress were assessed pre- and post-training, in quiet and in noise. SRN psychophysical thresholds showed a significant improvement (78% on average) over the training period, but performance on other psychophysical tasks did not change. LNT scores in noise improved significantly post-training by 11% on average compared with three pretraining baseline measures. N1P2 amplitude changed post-training for /baba/ in quiet (p = 0.005, visit 3 pretraining versus visit 4 post-training). CAEP changes did not correlate with behavioral measures. CI recipients' clinical records indicated a plateau in speech perception performance prior to participation in the study. A short period of intensive psychophysical training produced small but significant gains in speech perception in noise and spectral discrimination ability. There remain questions about the most appropriate type of training and the duration or dosage of training that provides the most robust outcomes for adults with CIs. PMID:27587925

  7. Effects of left primary motor and dorsolateral prefrontal cortex transcranial direct current stimulation on laser-evoked potentials in migraine patients and normal subjects.

    Science.gov (United States)

    Vecchio, Eleonora; Ricci, Katia; Montemurno, Anna; Delussi, Marianna; Invitto, Sara; de Tommaso, Marina

    2016-07-28

    Migraine is characterized by an altered cortical excitability. Because transcranial direct current stimulation (tDCS) can change brain activity noninvasively, it is possible to hypothesize its efficacy in modulating pain in migraine. In this study, we compared the effects of tDCS of the left primary motor cortex (M1) and left dorsolateral prefrontal cortex (DLPFC) both on subjective pain and on evoked responses induced by laser stimulation (LEPs). Thirty-two patients and sixteen controls were randomized to receive sham stimulation and real tDCS with the anode centered over M1 or DLPFC. Laser Evoked potentials were recorded in basal, sham and tDCS conditions. We did not find significant acute changes in LEPs parameters and pain perception among subjects who received tDCS of both M1 and DLPFC. After DLPFC tDCS, we observed a significant increase of N2-P2 component habituation in migraine patients while M1 stimulation reduced it. These findings may suggest a modulation of abnormal pain processing induced by DLPFC and M1 anodal tDCS and outline the need for future investigations exploring the possible neuronal plasticity changes supporting the clinical effect on migraine. PMID:27208831

  8. The Potential of Deweyan-Inspired Action Research

    Science.gov (United States)

    Stark, Jody L.

    2014-01-01

    In its broadest sense, pragmatism could be said to be the philosophical orientation of all action research. Action research is characterized by research, action, and participation grounded in democratic principles and guided by the aim of social improvement. Furthermore, action research is an active process of inquiry that does not admit…

  9. Relationships between sensory “gating out” and sensory “gating in” of auditory evoked potentials in schizophrenia: a pilot study

    Science.gov (United States)

    Gjini, Klevest; Arfken, Cynthia; Boutros, Nash N.

    2010-01-01

    The interrelationship between the ability to inhibit incoming redundant input (gating out) and the ability of the brain to respond when the stimulus changes (gating in), has not been extensively examined. We administered a battery of auditory evoked potential tests to a group of chronic, medicated schizophrenia patients (N=12) and a group of healthy subjects (N=12) in order to examine relationships between “gating out” measures (suppression with repetition of the P50, N100, and P200 evoked responses), and the mismatch negativity (MMN) and the P300 event related potentials as measures of “gating in”. Gating ratios for N100 and P200 in a visual attention paired-click task differed significantly between groups. Mismatch negativity and P300 potential amplitudes were also significantly reduced in the patient group. When including all subjects (N=24) a negative correlation was found between the P50 gating and the amplitude of the MMN. In healthy subjects this correlation was significantly stronger compared to schizophrenia patients. While no significant correlation was noted between the amplitudes of the P300 and any gating measures when all 24 subjects were included, a significant negative correlation was seen between the P200 gating and the P300 amplitudes in schizophrenia patients; an opposite trend was noted in healthy subjects. Finally, a positive correlation was seen between the P300 and MMN (to abstract deviance) amplitudes in healthy subjects, but the opposite was found in patients. These results suggest that further study of these interrelationships could inform the understanding of information processing abnormalities in schizophrenia. PMID:20537865

  10. Clinical Study on Effect of Electro-acupuncture Combined with Different Anesthetics on Auditory-evoked Potential Index

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Objective: To observe the effect of electro-acupuncture (EA) on auto regressive with exogenous input model (ARX-model) auditory evoked index (AAI) in patients anesthetized with different anesthetics. Methods: Forty-eight adult patients undergoing scheduled surgical operation were enrolled and divided into two groups (24 in each group) according to the anesthetics applied, Group A was anesthetized with propofol sedation and Group B with Isoflurane-epidural anesthesia. Group A was subdivided into three groups of low, middle and high concentration of target effect-site of 1.0 μg/ml, 1.5 μg/ml and 2.0 μg/ml through target controlled infusion (TCI) and Group B into 3 subgroups of minimum alveolar effective concentration of isoflurane (0.4 MAC, 0.6 MAC and 0.8 MAC for B1, B2 and B3 subgroups) respectively, with 8 patients in every subgroup. EA on acupoints of Hegu (LI4) and Neiguan (P6) was applied on all the patients during anesthesia, and the change of AAI at various time points was recorded. Results: In the three subgroups of Group A, levels of AAI were significantly elevated in the first few minutes after EA, and significantly lowered 20 min after EA in subgroup A2. While in the subgroups of Group B, except the elevating in Group B1 1 -2 min after EA, levels of AAI remained unchanged at other time points. Conclusion: Pain response could be reflected by AAI during EA. EA could enhance the sedative effect of propofol in middle concentration, but its effect on isoflurane epidural anesthesia is insignificant.

  11. Pressure wave model for action potential propagation in excitable cells

    CERN Document Server

    Rvachev, M M

    2003-01-01

    Speed of propagation of small-amplitude pressure waves through the cytoplasmic interior of myelinated and unmyelinated axons of different diameters is theoretically estimated and is found to generally agree with the action potential (AP) conduction velocities. This remarkable coincidence allows to surmise a model in which AP spread along axon is propelled not by straggling ionic currents as in the widely accepted local circuit theory, but by mechanoactivation of the membrane ion channels by a traveling pressure pulse. Hydraulic pulses propagating in the viscous axoplasm are calculated to decay over ~1 mm distances, and it is further hypothesized that it is the role of influxing during the AP calcium ions to activate membrane skeletal protein network attached to the membrane cytoplasmic side for a brief radial contraction amplifying the pressure pulse and preventing its decay. The model correctly predicts that the AP conduction velocity should vary as the one-half power of axon diameter for large unmyelinated ...

  12. Compound sensory action potential in normal and pathological human nerves

    DEFF Research Database (Denmark)

    Krarup, Christian

    2004-01-01

    at different conduction distances are determined by summation of SFAPs of varying fiber diameters, and differ in this respect, also, from the compound muscle action potential (CMAP) for which conduction velocities are determined by the very fastest fibers in the nerve. The effect and extent of temporal...... dispersion over increasing conduction distance is greater for the SNAP than CMAP, and demonstration of conduction block is therefore difficult. In addition, the effect of temporal dispersion on amplitude and shape is strongly dependent on the number of conducting fibers and their distribution, and...... in different polyneuropathies. In this review, different factors that characterize sensory fibers and set the SNAP apart from the CMAP are discussed to emphasize the supplementary and complementary information that can be obtained from sensory conduction studies. Sensory conduction studies require particular...

  13. The motor evoked potential in aids and HAM/TSP State of the evidence El potencial evocado motor en SIDA y HAM/PET

    Directory of Open Access Journals (Sweden)

    Fidias E. Leon-Sarmiento

    2009-12-01

    Full Text Available OBJECTIVE: We aimed to better understand the involvement of the corticospinal tract, assessed by non-invasive transcranial stimulation, in order to determine the actual involvement of the motor system in patients with HAM/TSP and AIDS. METHOD: An exhaustive MEDLINE search for the period of 1985 to 2008 for all articles cross-referenced for "HTLV-I, HTLV-II, HTLV-III and HIV, HIV1, HIV2, evoked potential, motor evoked potential, high voltage electrical stimulation, transcranial magnetic stimulation, magnetic stimulation, corticomotor physiology, motor pathways, acquired immunodeficiency syndrome, AIDS, SIDA, tropical spastic paraparesis, HTLV-I-associated myelopathy, HAM, TSP, and HAM/TSP" were selected and analysed. RESULTS: Eighteen papers published in English, Spanish, Portuguese, French and Japanese were identified. Only the central motor conduction time has been analyzed in seropositive patients to human retroviruses. The investigations done on HAM/TSP support the involvement of the pyramidal tract mainly at lower levels, following a centripetal pattern; in AIDS, such an involvement seems to be more prominent at brain levels following a centrifugal pattern. CONCLUSION: The central motor conduction time abnormalities and involvement differences of the corticospinal tract of patients with AIDS and HAM/TSP dissected here would allow to re-orient early neurorehabilitation measures in these retroviruses-associated neurodegenerative disorders. Besides this, more sophisticated and sensitive non-invasive corticospinal stimulation measures that detect early changes in thalamocortical-basal ganglia circuitry will be needed in both clinically established as well as asymptomatic patients at times when the fastest corticospinal fibers remain uninvolved.OBJETIVO: Investigar el compromiso del tracto piramidal, evaluado por estimulación trascranial no invasiva, en pacientes afectados por SIDA y HAM/TSP. MÉTODO: Se realizó una búsqueda en la base de

  14. Consensus on the use of neurophysiological tests in the intensive care unit (ICU): electroencephalogram (EEG), evoked potentials (EP), and electroneuromyography (ENMG)

    DEFF Research Database (Denmark)

    Guérit, J-M; Amantini, A; Amodio, P;

    2009-01-01

    STUDY AIM: To provide a consensus of European leading authorities about the optimal use of clinical neurophysiological (CN) tests (electroencephalogram [EEG]; evoked potentials [EP]; electroneuromyography [ENMG]) in the intensive care unit (ICU) and, particularly, about the way to make these tests...... contribution to all other experts. A complete consensus has been reached when submitting the manuscript. RESULTS: What the group considered as the best classification systems for EEG and EP abnormalities in the ICU is first presented. CN tests are useful for diagnosis (epilepsy, brain death, and neuromuscular...... disorders), prognosis (anoxic ischemic encephalopathy, head trauma, and neurologic disturbances of metabolic and toxic origin), and follow-up, in the adult, paediatric, and neonatal ICU. Regarding prognosis, a clear distinction is made between these tests whose abnormalities are indicative of an ominous...

  15. Interactions between dyspnea and the brain processing of nociceptive stimuli:experimental air hunger attenuates laser-evoked brain potentials in humans.

    Directory of Open Access Journals (Sweden)

    Laurence eDANGERS

    2015-12-01

    Full Text Available Dyspnea and pain share several characteristics and certain neural networks and interact with each other. Dyspnea-pain counter-irritation consists of attenuation of preexisting pain by intercurrent dyspnea and has been shown to have neurophysiological correlates in the form of inhibition of the nociceptive spinal reflex RIII and laser-evoked potentials (LEPs. Experimentally induced exertional dyspnea inhibits RIII and LEPs, while air hunger dyspnea does not inhibit RIII despite its documented analgesic effects. We hypothesized that air hunger may act centrally and inhibit LEPs. LEPs were obtained in 12 healthy volunteers (age: 21-29 during spontaneous breathing (FB, ventilator-controlled breathing (VC tailored to FB, after inducing air hunger by increasing the inspired fraction of carbon dioxide -FiCO2- (VCCO2, and during ventilator-controlled breathing recovery (VCR. VCCO2 induced intense dyspnea (visual analogue scale = 63% ± 6% of full scale, p<0.001 vs. VC, predominantly of the air hunger type. VC alone reduced the amplitude of the N2-P2 component of LEPs (∆ = 24.0% ± 21.1%, p<0.05, effect-size = 0.74 predominantly through a reduction in P2, and the amplitude of this inhibition was further reduced by inducting air hunger (∆ = 22.6% ± 17.9%, p<0.05, effect-size = 0.53, predominantly through a reduction in N2. Somatosensory-evoked potentials (SEPs were not affected by VC or VCCO2, suggesting that the observed effects are specific to pain transmission. We conclude that air hunger interferes with the cortical mechanisms responsible for the cortical response to painful laser skin stimulation, which provides a neurophysiological substrate to the central nature of its otherwise documented analgesic effects.

  16. Cerebral monitoring in the operating room and the intensive care unit - an introductory for the clinician and a guide for the novice wanting to open a window to the brain. Part II: Sensory-evoked potentials (SSEP, AEP, VEP).

    Science.gov (United States)

    Freye, Enno

    2005-04-01

    An evoked potential differs from the EEG mainly in two ways: 1. The EEG is a random, continuous signal, which arises from the ongoing activity of the outer layers of the cortex. An evoked potential is the brain's response to a repetitive stimulus along a specific nerve pathway. 2.EEG signals range from 10-200 milliVolt (mV). Evoked potentials are smaller in amplitude (1-5-20 microVolt requiring precise electrode positioning and special techniques (signal averaging) to extract the specific response from the underlying EEG "noise". The technique of signal averaging, as originally described by Dawson in 1954 [69J, has been further developed in computer processing. The technique is now used by applying a stimulus repeatedly--preferably at randomized intervals--and to record the evoked response over the corresponding area of the brain, averaging out mathematically the change over the number of stimuli. Rationale for the use of EPs in the OR and the ICU. Evoked potentials (EPs) serve the following major purposes: 1. Monitoring of the functional integrity of neural structures that may be at risk during, for instance, ECC (extracorporeal circulation) or endarterectomy indicating cerebral hypoxia. 2. Monitoring of the effects of anesthetic agents and other centrally active drugs, which, besides the cortex, affect deeper neuronal structures. 3. Orthopedic cases where the spinal cord is at risk such as Harrington rod insertion and removal. 4. Clamping of the abdominal aortic artery during aneurysmectomy resulting in a potential damage of the lower parts of the spinal cord. 5. Clipping of an intracerebral aneurysm, which may be impeding blood flow to vital cerebral textures. 6. An indicator of cerebral hypoxia when the blood pressure is deliberately lowered. 7. Operation on peripheral nerves and nerve roots to identify early trauma. 8. Monitoring the cerebral function during controlled hypothermia when the EEG becomes flat. 9. Monitoring of the pathophysiological conditions

  17. Effects of estragole on the compound action potential of the rat sciatic nerve

    Directory of Open Access Journals (Sweden)

    J.H. Leal-Cardoso

    2004-08-01

    Full Text Available Estragole, a relatively nontoxic terpenoid ether, is an important constituent of many essential oils with widespread applications in folk medicine and aromatherapy and known to have potent local anesthetic activity. We investigated the effects of estragole on the compound action potential (CAP of the rat sciatic nerve. The experiments were carried out on sciatic nerves dissected from Wistar rats. Nerves, mounted in a moist chamber, were stimulated at a frequency of 0.2 Hz, with electric pulses of 50-100-µs duration at 10-20 V, and evoked CAP were monitored on an oscilloscope and recorded on a computer. CAP control parameters were: peak-to-peak amplitude (PPA, 9.9 ± 0.55 mV (N = 15, conduction velocity, 92.2 ± 4.36 m/s (N = 15, chronaxy, 45.6 ± 3.74 µs (N = 5, and rheobase, 3.9 ± 0.78 V (N = 5. Estragole induced a dose-dependent blockade of the CAP. At 0.6 mM, estragole had no demonstrable effect. At 2.0 and 6.0 mM estragole, PPA was significantly reduced at the end of 180-min exposure of the nerve to the drug to 85.6 ± 3.96 and 13.04 ± 1.80% of control, respectively. At 4.0 mM, estragole significantly altered PPA, conduction velocity, chronaxy, and rheobase (P <= 0.05, ANOVA; N = 5 to 49.3 ± 6.21 and 77.7 ± 3.84, 125.9 ± 10.43 and 116.7 ± 4.59%, of control, respectively. All of these effects developed slowly and were reversible upon a 300-min wash-out. The data show that estragole dose-dependently blocks nerve excitability.

  18. Modelling Action Potential Generation and Propagation in Fibroblastic Cells

    Science.gov (United States)

    Torres, J. J.; Cornelisse, L. N.; Harks, E. G. A.; Theuvenet, A. P. R.; Ypey, D. L.

    2003-04-01

    Using a standard Hodgkin-Huxley (HH) formalism, we present a mathematical model for action potential (AP) generation and intercellular AP propagation in quiescent (serum-deprived) normal rat kidney (NRK) fibroblasts [1], based on the recent experimental identification of the ion channels involved [2]. The principal ion channels described are those of an inwardly rectifying K+ conductance (GKIR), an L-type calcium conductance (GCaL), an intracellular calcium activated Cl- conductance (GCl(Ca)), a residual leak conductance Gleak, and gap junctional channels between the cells (Ggj). The role of each one of these components in the particular shape of the AP wave-form has been analyzed and compared with experimental observations. In addition, we have studied the role of subcellular processes like intracellular calcium dynamics and calcium buffering in AP generation. AP propagation between cells was reconstructed in a hexagonal model of cells coupled by Ggj with physiological conductance values. The model revealed an excitability mechanism of quiescent NRK cells with a particular role of intracellular calcium dynamics. It allows further explorations of the mechanism of signal generation and transmission in NRK cell cultures and its dependence on growth conditions.

  19. Pharmacological actions of statins: potential utility in COPD

    Directory of Open Access Journals (Sweden)

    T. E. Eaton

    2009-12-01

    Full Text Available Chronic obstructive pulmonary disease (COPD is characterised by minimally reversible airflow limitation and features of systemic inflammation. Current therapies for COPD have been shown to reduce symptoms and infective exacerbations and to improve quality of life. However, these drugs have little effect on the natural history of the disease (progressive decline in lung function and exercise tolerance and do not improve mortality. The anti-inflammatory effects of statins on both pulmonary and systemic inflammation through inhibition of guanosine triphosphatase and nuclear factor-B mediated activation of inflammatory and matrix remodelling pathways could have substantial benefits in patients with COPD due to the following. 1 Inhibition of cytokine production (tumour necrosis factor-, interleukin (IL-6 and IL-8 and neutrophil infiltration into the lung; 2 inhibition of the fibrotic activity in the lung leading to small airways fibrosis and irreversible airflow limitation; 3 antioxidant and anti-inflammatory (IL-6 mediated effects on skeletal muscle; 4 reduced inflammatory response to pulmonary infection; and 5 inhibition of the development (or reversal of epithelial-mesenchymal transition, a precursor event to lung cancer. This review examines the pleiotropic pharmacological action of statins which inhibit key inflammatory and remodelling pathways in COPD and concludes that statins have considerable potential as adjunct therapy in COPD.

  20. Pharmacological actions of statins: potential utility in COPD.

    Science.gov (United States)

    Young, R P; Hopkins, R; Eaton, T E

    2009-12-01

    Chronic obstructive pulmonary disease (COPD) is characterised by minimally reversible airflow limitation and features of systemic inflammation. Current therapies for COPD have been shown to reduce symptoms and infective exacerbations and to improve quality of life. However, these drugs have little effect on the natural history of the disease (progressive decline in lung function and exercise tolerance) and do not improve mortality. The anti-inflammatory effects of statins on both pulmonary and systemic inflammation through inhibition of guanosine triphosphatase and nuclear factor-κB mediated activation of inflammatory and matrix remodelling pathways could have substantial benefits in patients with COPD due to the following. 1) Inhibition of cytokine production (tumour necrosis factor-α, interleukin (IL)-6 and IL-8) and neutrophil infiltration into the lung; 2) inhibition of the fibrotic activity in the lung leading to small airways fibrosis and irreversible airflow limitation; 3) antioxidant and anti-inflammatory (IL-6 mediated) effects on skeletal muscle; 4) reduced inflammatory response to pulmonary infection; and 5) inhibition of the development (or reversal) of epithelial-mesenchymal transition, a precursor event to lung cancer. This review examines the pleiotropic pharmacological action of statins which inhibit key inflammatory and remodelling pathways in COPD and concludes that statins have considerable potential as adjunct therapy in COPD. PMID:20956147