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PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
3
pubmed:dateCreated
1987-5-21
pubmed:abstractText
Neurons in the visual cortex respond selectively to stimulus orientation and spatial frequency. Changes in response amplitudes of these neurons could be the neurophysiological basis of orientation and spatial frequency discrimination. We have estimated the minimum differences in stimulus orientation and spatial frequency that can produce reliable changes in the responses of individual neurons in cat visual cortex. We compare these values with orientation and spatial frequency discrimination thresholds determined behaviorally. Slopes of the tuning functions and response variability determine the minimum orientation and spatial frequency differences that can elicit a reliable response change. These minimum values were obtained from single cells using receiver operating characteristic (ROC) analysis. The average minimum orientation and spatial frequency differences that could be signaled reliably by cells from our sample were 6.4 degrees (n = 22) and 21.3% (n = 18), respectively. These values are approximately 0.20 of the average full tuning width at one-half height of the cells. Although these average values are well above the behaviorally determined thresholds, the most selective cells signaled orientation and frequency differences of 1.84 degrees and 5.25%, respectively. These values are of the same order of magnitude as the behavioral thresholds. We show that, because of slow fluctuations in a cell's responsivity, ROC analysis overestimates response variability. We estimate that these slow response fluctuations elevated our estimates of single cell "thresholds" by, on average, 30%. Our data point to an approximate correspondence between orientation and spatial frequency discrimination "thresholds" determined behaviorally and those estimated from the most selective single cortical cells. Interpretation of this quantitative correspondence is considered in the discussion.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:status
MEDLINE
pubmed:month
Mar
pubmed:issn
0022-3077
pubmed:author
pubmed:issnType
Print
pubmed:volume
57
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
755-72
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed:year
1987
pubmed:articleTitle
Visual orientation and spatial frequency discrimination: a comparison of single neurons and behavior.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S., Research Support, Non-U.S. Gov't