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Predicate | Object |
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rdf:type | |
lifeskim:mentions | |
pubmed:issue |
1
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pubmed:dateCreated |
1985-2-25
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pubmed:abstractText |
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.
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pubmed:grant | |
pubmed:language |
eng
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pubmed:journal | |
pubmed:citationSubset |
IM
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pubmed:status |
MEDLINE
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pubmed:issn |
0014-4819
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pubmed:author | |
pubmed:issnType |
Print
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pubmed:volume |
57
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pubmed:owner |
NLM
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pubmed:authorsComplete |
Y
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pubmed:pagination |
1-8
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pubmed:dateRevised |
2009-11-11
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pubmed:meshHeading |
pubmed-meshheading:6519219-Animals,
pubmed-meshheading:6519219-Biophysical Phenomena,
pubmed-meshheading:6519219-Biophysics,
pubmed-meshheading:6519219-Cats,
pubmed-meshheading:6519219-Evoked Potentials, Visual,
pubmed-meshheading:6519219-Genetic Variation,
pubmed-meshheading:6519219-Geniculate Bodies,
pubmed-meshheading:6519219-Humans,
pubmed-meshheading:6519219-Light,
pubmed-meshheading:6519219-Male,
pubmed-meshheading:6519219-Rats,
pubmed-meshheading:6519219-Species Specificity,
pubmed-meshheading:6519219-Visual Acuity,
pubmed-meshheading:6519219-Visual Pathways,
pubmed-meshheading:6519219-Visual Perception
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pubmed:year |
1984
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pubmed:articleTitle |
The effect of contrast and spatial frequency on the visual evoked potential of the hooded rat.
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pubmed:publicationType |
Journal Article,
Comparative Study,
Research Support, U.S. Gov't, P.H.S.,
Research Support, Non-U.S. Gov't
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