Dynamics of primate P retinal ganglion cells: responses to chromatic and achromatic stimuli.
1. The majority of primate retinal ganglion cells (RGCs) project to the parvocellular layers of the lateral geniculate nucleus (LGN). These P cells play a central role in early visual processing. 2. An improved method of systems analysis has allowed us to explore the dynamics of the colour-opponent subregions of P-cell receptive fields with a single chromatic stimulus. The data show that the centre and surround subregions of the P-cell receptive field have similar temporal responses, but the surround is slightly delayed. The centre and surround demonstrate a large degree of chromatic selectivity. 3. The responses of the centre and surround subregions were fitted with a linear model and the model was used to predict the responses of P cells to new chromatic and achromatic stimuli. Although linear models predict the chromatic responses well, simple linear combinations of centre and surround responses fail to predict P-cell responses to achromatic stimuli. 4. The temporal responses of the different subpopulations of P cells, such as ON/OFF or L-centre/M-centre were not significantly different.
Benardete
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The Rockefeller University, 1230 York Avenue, New York, NY 10021, USA. ebak@rcn.com
Kaplan
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D000818:Animals; D002478:Cells, Cultured; D003116:Color; D007700:Kinetics; D008027:Light; D008252:Macaca fascicularis; D008297:Male; D012165:Retinal Ganglion Cells / Q000502:physiology*