Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
3
pubmed:dateCreated
2004-8-27
pubmed:abstractText
Based on extracellular recordings from 69 lateral geniculate nucleus (LGN) cells in the anesthetized cat, we found spatial summation within their receptive fields to be dependent on the contrast of the stimuli presented. By fitting the summation curves to a difference of Gaussians model, we attributed this contrast-dependent effect to an actual change in the size of the center mechanism. Analogous changes in spatial frequency tuning were also observed, specifically increased peaks and cut-off frequencies with contrast. These effects were seen across the populations of both X and Y cell types. In a few cases, LGN cells were recorded simultaneously with one of their retinal ganglion cell (RGC) inputs (S-potentials). In every case, the RGCs exhibited similar contrast-dependent effects in the space and spatial-frequency domains. We propose that this contrast dependency in the retinal ganglion cells results directly from a reduction in the size of the center mechanism due to an increase in contrast. We also propose that these properties first arise in the retina and are transmitted passively through the LGN to visual cortex.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:status
MEDLINE
pubmed:month
Sep
pubmed:issn
0022-3077
pubmed:author
pubmed:issnType
Print
pubmed:volume
92
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
1708-17
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
2004
pubmed:articleTitle
Contrast-dependent spatial summation in the lateral geniculate nucleus and retina of the cat.
pubmed:affiliation
Department of Neuroscience, School of Medicine, 215 Stemmler Hall, University of Pennsylvania, Philadelphia, PA 19104-6060, USA. nolt@mail.med.upenn.edu
pubmed:publicationType
Journal Article, Comparative Study