Changes of occipital evoked response during luminance discrimination in man.

2011 ◽  
pp. 343-348
Author(s):  
Elio Garcia-Austt ◽  
Washington Buno ◽  
Pablo Handler
Keyword(s):  
Evoked Response ◽  
Luminance Discrimination

Visual Evoked-Response Correlates of Speechreading Performance in Normal-Hearing Adults

1983 ◽  
Vol 26 (1) ◽  
pp. 2-9 ◽  
Author(s):  
Vincent J. Samar ◽  
Donald G. Sims
Keyword(s):  
Multiple Correlation Coefficient ◽  
Evoked Response ◽  
Multiple Correlation ◽  
Potential Significance ◽  
Visual Evoked Response ◽  
Latency Measure ◽  
Two Measures ◽  
Components Analysis ◽  
The Relationship ◽  
Visual Evoked

The relationship between the latency of the negative peak occurring at approximately 130 msec in the visual evoked-response (VER) and speechreading scores was investigated. A significant product-moment correlation of -.58 was obtained between the two measures, which confirmed the fundamental effect but was significantly weaker than that previously reported in the literature (-.90). Principal components analysis of the visual evoked-response waveforms revealed a previously undiscovered early VER component, statistically independent of the latency measure, which in combination with two other components predicted speechreading with a multiple correlation coefficient of S4. The potential significance of this new component for the study of individual differences in speechreading ability is discussed.

An Adaptive and Learning System for Feedback-Controlled Evoked Response Studies

1981 ◽  
Vol 20 (03) ◽  
pp. 169-173
Author(s):  
J. Wagner ◽  
G. Pfurtscheixer
Keyword(s):  
Brain Activity ◽  
Evoked Response ◽  
Learning System ◽  
Time Interval ◽  
Electrical Brain Activity ◽  
Long Time ◽  
The Subject ◽  
Eeg Power ◽  
Stimulation System ◽  
Background Eeg

The shape, latency and amplitude of changes in electrical brain activity related to a stimulus (Evoked Potential) depend both on the stimulus parameters and on the background EEG at the time of stimulation. An adaptive, learnable stimulation system is introduced, whereby the subject is stimulated (e.g. with light), whenever the EEG power is subthreshold and minimal. Additionally, the system is conceived in such a way that a certain number of stimuli could be given within a particular time interval. Related to this time criterion, the threshold specific for each subject is calculated at the beginning of the experiment (preprocessing) and adapted to the EEG power during the processing mode because of long-time fluctuations and trends in the EEG. The process of adaptation is directed by a table which contains the necessary correction numbers for the threshold. Experiences of the stimulation system are reflected in an automatic correction of this table. Because the corrected and improved table is stored after each experiment and is used as the starting table for the next experiment, the system >learns<. The system introduced here can be used both for evoked response studies and for alpha-feedback experiments.

scholarly journals Evaluation of the effects of acetylcholinesterase inhibitors in the zebrafish touch-evoked response: quantitative vs. qualitative assessment

2020 ◽  
Vol 32 (1) ◽  
Author(s):  
Laura Guzman ◽  
Gisela Besa ◽  
Daniela Linares ◽  
Lara González ◽  
Caterina Pont ◽  
...  
Keyword(s):  
Neurological Diseases ◽  
Acetylcholinesterase Inhibitors ◽  
Cost Effective ◽  
Evoked Response ◽  
New Drugs ◽  
Screening Tools ◽  
Qualitative Assessment ◽  
Toxicity Screening ◽  
Novel Treatments ◽  
Ache Inhibitors

Abstract Background The difficulty of finding new treatments for neurological diseases with great impact in our society like Alzheimer’s disease can be ascribed in part to the complexity of the nervous system and the lack of quick and cost-effective screening tools. Such tools could not only help to identify potential novel treatments, but could also be used to test environmental contaminants for their potential to cause neurotoxicity. It has been estimated that 5–10% of the anthropogenic chemicals are developmental neurotoxic (DNT) and exposure to DNT compounds has been linked to several neurological diseases. Within this study we were testing the applicability of a quick and cost-effective behavioural test using zebrafish embryos: the touch-evoked response assay, in this case, an assay evaluating the swimming response to a tap in the tail. Two acetylcholinesterase (AChE) inhibitors positive controls (paraoxon and huprine Y), as well as 10 huprine-derivative compounds were tested and the results were evaluated using 2 different methods, a quantitative and a qualitative one. Results We could show that the methodology presented is able to detect behavioural effects of AChE inhibitors. A good correlation between the results obtained with the quantitative and the qualitative method was obtained (R2 = 0.84). Conclusions Our proposed method enables combination of screening for new drugs with toxicity screening in a whole embryo model alternative to animal experimentation, thereby merging 2 drug development steps into one.

Epileptiform activity in the hippocampus produced by tetraethylammonium

1990 ◽  
Vol 64 (4) ◽  
pp. 1077-1088 ◽  
Author(s):  
P. A. Rutecki ◽  
F. J. Lebeda ◽  
D. Johnston
Keyword(s):  
Potassium Channel ◽  
Voltage Clamp ◽  
Channel Blocker ◽  
Mossy Fiber ◽  
Reversal Potential ◽  
Evoked Response ◽  
Epileptiform Discharge ◽  
Extracellular Potassium ◽  
Potassium Channel Blocker ◽  
Epileptiform Discharges

1. The epileptiform discharges in the CA3 region of the rat hippocampal slice produced by bath application of the potassium channel blocker tetraethylammonium (TEA) were investigated. The effects of a convulsant (5 mM) and subconvulsant (0.5 mM) concentration of TEA on the mossy fiber-evoked synaptic currents were studied by the use of voltage-clamp techniques to determine whether TEA, like 4-aminopyridine (4-AP), another potassium channel blocker and convulsant, increased both inhibitory and excitatory components of the synaptic response. 2. At extracellular potassium concentrations of 2.5 mM, TEA (5 mM) was found to produce spontaneously occurring epileptiform discharges that could be recorded extracellularly. The intracellular correlate of the epileptiform discharge, the paroxysmal depolarizing shift (PDS), could be reversed in polarity by depolarizing the membrane and was associated with a large increase in membrane conductance. These results suggest that a synaptically mediated potential underlies the generation of the epileptiform discharge. 3. The reversal potential for the PDS was dependent on the time, relative to the extracellularly recorded field discharge, at which the measurement was made. In current clamp the mean reversal potential of the PDS measured at the midpoint of the extracellular discharge was -3.3 +/- 2.9 (SE) mV (n = 9). The reversal potential of the PDS was considerably more negative when measured either before or after the midpoint of the extracellular discharge, suggesting the presence of an inhibitory synaptic component. In voltage clamp similar results were obtained and a large conductance change was found to be associated with the PDS. These results suggest that the synaptic conductance associated with the PDS has both inhibitory and excitatory components. 4. TEA increased significantly the mossy fiber-evoked, early-inhibitory conductance. A convulsant concentration (5 mM) increased the conductance measured 15 ms after the stimulus from 39.7 +/- 8.7 to 87.2 +/- 8.0 nS (n = 6). The reversal potential associated with the conductance depolarized from -68.3 +/- 3.4 to -58.3 +/- 4.0 mV after 5 mM TEA. A subconvulsant concentration of TEA (0.5 mM) also increased the conductance of the mossy fiber-evoked response at 15 ms after the stimulus from 49.5 +/- 3.1 to 63.1 +/- 6.1 nS (n = 4) without an associated shift in reversal potential. 5. The late-inhibitory component of the mossy fiber-evoked response, when present, was increased by 5 mM TEA and unchanged by 0.5 mM TEA. 6. The excitatory mossy fiber-evoked synaptic current was studied in the presence of picrotoxin and was found to be increased and prolonged by 5 mM TEA.(ABSTRACT TRUNCATED AT 400 WORDS)

Assessment of Hearing Impairment in NICU Graduates by Otoacoustic Emission and Brainstem Evoked Response Audiometry Tests

2020 ◽  
Vol 34 (3) ◽  
pp. 109-117
Author(s):  
Aparna Aradhana ◽  
Gadadhar Sarangi ◽  
Prasant Saboth ◽  
Radha Tripathy
Keyword(s):  
Risk Factors ◽  
Hearing Impairment ◽  
Very Low Birth Weight ◽  
Birth Asphyxia ◽  
Otoacoustic Emission ◽  
Evoked Response ◽  
Complete Evaluation ◽  
Brainstem Evoked Response Audiometry ◽  
Tertiary Teaching ◽  
Evoked Response Audiometry

Objectives: To find out the incidence of hearing impairment in Neonatal Intensive Care Unit (NICU)-admitted newborns and to correlate between several risk factors. Design: Prospective observational study. Setting: In a tertiary teaching hospital of Odisha between October 2014 and October 2016. Study population: 100 newborns delivered in the institution and admitted in NICU with usual indications and risk factors that underwent otoacoustic emission 1 and 2 (OAE1, OAE2) and Brainstem Evoked Response Audiometry (BERA). Results: 84 babies in OAE1 and 86 babies in OAE2 got “pass” results. In BERA test, 92 babies got normal waveform. 7 (13.7%) of 51 premature babies, 5 (38.5%) of 13 very low birth weight babies, 7 (17.5%) of 40 babies receiving ototoxic medication for >5 days, 7 (31.8%) of 22 babies with hyperbilirubinemia, 6 (42.9%) of 14 babies with sepsis, 5 (20%) of 20 babies with birth asphyxia, 3 (60%) of 5 babies under mechanical ventilation for >5 days, 1 baby with ear abnormality, and 1 (50%) out of 2 babies with congenital infections had hearing impairment and statistically significant association with abnormal OAE and BERA test. Conclusion: There is high incidence of hearing loss in NICU-admitted newborns. OAE and BERA both should be performed for complete evaluation of hearing. Important risk factors are elaborated. Predischarge hearing assessment in NICU is most important.

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