Document Detail


The effect of contrast and spatial frequency on the visual evoked potential of the hooded rat.
MedLine Citation:
PMID:  6519219     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Transient and steady-state visual evoked potentials, obtained with counterphase modulated grating patterns, were recorded through chronically implanted electrodes in lightly anesthetized and unanesthetized hooded rats. As a function of spatial frequency, the latency of the major positive wave (P1) of the transient VEP was minimal with a 0.1 cycles per degree (cpd) grating as stimulus. The amplitude of the P1-N2 component remained constant from 0.04 to 0.20 cpd and then decreased with higher spatial frequencies. The function relating amplitude of steady-state VEP to spatial frequency at high contrast depended on temporal frequency: It had a band-pass form at 5.0 Hz and a low-pass form at 8.4 Hz. As a function of contrast, the latency of the P1 wave linearly decreased and its amplitude increased with increments of contrast up to 55%. The contrast function of the amplitude of the second harmonic of the steady-state VEP (8.4 Hz) showed two linear segments: one for low contrasts with a shallow slope and one for high contrasts with a steep slope, suggesting two distinct contrast mechanisms.
Authors:
C Harnois; I Bodis-Wollner; M Onofrj
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Publication Detail:
Type:  Comparative Study; Journal Article; Research Support, Non-U.S. Gov't; Research Support, U.S. Gov't, P.H.S.    
Journal Detail:
Title:  Experimental brain research     Volume:  57     ISSN:  0014-4819     ISO Abbreviation:  Exp Brain Res     Publication Date:  1984  
Date Detail:
Created Date:  1985-02-25     Completed Date:  1985-02-25     Revised Date:  2013-12-13    
Medline Journal Info:
Nlm Unique ID:  0043312     Medline TA:  Exp Brain Res     Country:  GERMANY, WEST    
Other Details:
Languages:  eng     Pagination:  1-8     Citation Subset:  IM; S    
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MeSH Terms
Descriptor/Qualifier:
Animals
Biophysical Phenomena
Biophysics
Cats
Evoked Potentials, Visual
Genetic Variation
Geniculate Bodies / cytology,  physiology
Humans
Light
Male
Rats
Species Specificity
Visual Acuity
Visual Pathways / physiology*
Visual Perception / physiology*
Grant Support
ID/Acronym/Agency:
EY01708/EY/NEI NIH HHS; EY01867/EY/NEI NIH HHS; NS-11631/NS/NINDS NIH HHS

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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