Linked Life Data

10751454

Source:http://linkedlifedata.com/resource/pubmed/id/10751454

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
8
pubmed:dateCreated
2000-5-15
pubmed:abstractText
In this study, we compare binocular and monocular mechanisms underlying contrast encoding by binocular simple cells in primary visual cortex. At mid to high levels of stimulus contrast, contrast gain of cortical neurons typically decreases as stimulus contrast is increased (). We have devised a technique by which it is possible to determine the relative contributions of monocular and binocular processes to such reductions in contrast gain. First, we model the simple cell as an adjustable linear mechanism with a static output nonlinearity. For binocular cells, the linear mechanism is sensitive to inputs from both eyes. To constrain the parameters of the model, we record from binocular simple cells in striate cortex. To activate each cell, drifting sinusoidal gratings are presented dichoptically at various relative interocular phases. Stimulus contrast for one eye is varied over a large range whereas that for the other eye is fixed. We then determine the best-fitting parameters of the model for each cell for all of the interocular contrast ratios. This allows us to determine the effect of contrast on the contrast gain of the system. Finally, we decompose the contrast gain into monocular and binocular components. Using the data to constrain the model for a fixed contrast in one eye and increased contrasts in the other eye, we find steep reductions in monocular gain, whereas binocular gain exhibits modest and variable changes. These findings demonstrate that contrast gain reductions occur primarily at a monocular site, before convergence of information from the two eyes.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:status
MEDLINE
pubmed:month
Apr
pubmed:issn
1529-2401
pubmed:author
pubmed:issnType
Electronic
pubmed:day
15
pubmed:volume
20
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
3017-32
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed:year
2000
pubmed:articleTitle
Contrast gain control in the visual cortex: monocular versus binocular mechanisms.
pubmed:affiliation
Group in Vision Science, School of Optometry, University of California, Berkeley, California 94720-2020, USA.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S., Research Support, U.S. Gov't, Non-P.H.S.