The receptive field of the primate P retinal ganglion cell, I: Linear dynamics.
The ganglion cells of the primate retina include two major anatomical and functional classes: P cells which project to the four parvocellular layers of the lateral geniculate nucleus (LGN), and M cells which project to the two magnocellular layers. The characteristics of the P-cell receptive field are central to understanding early form and color vision processing (Kaplan et al., 1990; Schiller & Logothetis, 1990). In this and in the following paper, P-cell dynamics are systematically analyzed in terms of linear and nonlinear response properties. Stimuli that favor either the center or the surround of the receptive field were produced on a CRT and modulated with a broadband signal composed of multiple m-sequences (Benardete et al., 1992b; Benardete & Victor, 1994). The first-order responses were calculated and analyzed in this paper (part I). The findings are: (1) The first-order responses of the center and surround depend linearly on contrast. (2) The dynamics of the center and surround are well described by a bandpass filter model. The most significant difference between center and surround dynamics is a delay of approximately 8 ms in the surround response. (3) In the LGN, these responses are attenuated and delayed by an additional 1-5 ms. (4) The spatial transfer function of the P cell in response to drifting sine gratings at three temporal frequencies was measured. This independent method confirmed the delay between the (first-order) responses of the center and surround. This delay accounts for the dependence of the spatial transfer function on the frequency of stimulation.
Benardete
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EA
Rockefeller University, New York, USA.
Kaplan
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D000818:Animals; D003118:Color Perception / Q000502:physiology*; D004594:Electrophysiology / Q000379:methods; D005556:Form Perception / Q000502:physiology*; D008252:Macaca fascicularis; D008297:Male; D009474:Neurons / Q000502:physiology*; D010775:Photic Stimulation; D012165:Retinal Ganglion Cells / Q000502:physiology*