A competitive model for spectral plasticity in the outer retina

In a previous paper, we reported that repetitive red 1ashes enhanced the red response of retinal luminosity-type horizontal cell (LHC) and depressed the cell’s green response; repetitive green 1ashes suppressed the cell’s red response, but caused trivial changes in its green response. Based on the idea that the spectral plasticity of the horizontal cell may re1ect some changes in synaptic e6cacy between the horizontal cell and various cones, a simple quantitative model was constructed. The process consists of three components: a linear :rst-order dynamics, a self-excitatory component within the same kind of synaptic population, and a cross-inhibitory component between di=erent kinds of synaptic populations. It is shown that the model prediction :ts reasonably well with the experimental data. The in1uence of relevant parameters on the model output was further inspected. Our :ndings suggest that there might be a competitive depression between the redand green-cone signals that converge onto LHCs. c © 2002 Elsevier Science B.V. All rights reserved.