Linked Life Data

6520632

Source:http://linkedlifedata.com/resource/pubmed/id/6520632

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
6
pubmed:dateCreated
1985-2-27
pubmed:abstractText
Directional units in the optic nerve of the California ground squirrel (Spermophilus beecheyi) were studied with respect to their response to diffuse light, preferred directions of motion, tuning for preferred direction, the relationship between spatial and directional tuning characteristics, and receptive-field size and areal summating properties. Directional units in the ground squirrel optic nerve are of the "on-off" type. No purely on or off units were encountered in a sample of 356 directionally selective fibers. The distribution of preferred directions of image motion for 356 units was significantly anisotropic; greater than 50% of the directional units prefer motion in the direction of the superior-nasal visual quadrant. Mean directional bandwidth, measured at half-amplitude response, for 39 units was 88.5 degrees. The distribution of directional bandwidths suggests that two subpopulations of directional units may exist a broadly tuned (106.4 degrees bandwidth) group preferring image motion in the superior-nasal direction, and a narrowly tuned group (59.9 degrees bandwidth) with a uniform distribution of preferred direction. Tuning for direction of motion and for spatial frequency were significantly positively correlated in a sample of 35 directional units. Area-vs.-response measures for directional units show that they possess excitatory discharge centers with a concentric antagonistic surround, plus a larger suppressive surround activated specifically by moving luminance contours, which may be asymmetric. Critical activation areas for directional units, as measured along orthogonal orientations, were highly positively correlated. This suggests that these receptive fields possess the property of linear spatial summation, not of luminance flux, but of areas of moving luminance contours.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:status
MEDLINE
pubmed:month
Dec
pubmed:issn
0022-3077
pubmed:author
pubmed:issnType
Print
pubmed:volume
52
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
1200-12
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed:year
1984
pubmed:articleTitle
Directional filter characteristics of optic nerve fibers in California ground squirrel (Spermophilus beecheyi).
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S.