Fine structure of receptive-field centers of X and Y cells of the cat.
We investigated the fine structure of receptive field centers of X and Y cells of the retina and lateral geniculate nucleus of the cat using sinusoidal grating stimuli of high spatial frequency. By measuring orientation tuning and spatial-frequency tuning at multiple orientations, the two-dimensional sensitivity distribution was examined. We found that receptive-field centers typically have multiple sensitivity peaks that can be modeled as several spatially offset subunits. A subunit structure was found in both X and Y cells, with an average number of subunits per receptive-field center of approximately 2.9 in X cells and approximately 4.6 in Y cells. In X cells these subunits may correspond to individual cone bipolar inputs. In Y cells, the subunits may reflect the structure of the dendritic tree. The observation of the subunit structure of the receptive-field center, in conjunction with manipulation of the retinal wiring through pharmacological intervention, may provide a new tool for probing the circuitry of the retina.
Soodak
R E
RE
Rockefeller University, New York, NY 10021.
Shapley
R M
RM
Kaplan
E
E
D000818:Animals; D002415:Cats; D004594:Electrophysiology; D005829:Geniculate Bodies / Q000502:physiology*; D008297:Male; D010775:Photic Stimulation; D012165:Retinal Ganglion Cells / Q000502:physiology*; D014794:Visual Fields; D014795:Visual Pathways / Q000502:physiology; D014796:Visual Perception / Q000502:physiology