A Retinal Ganglion Cell Model Based on Discrete Stochastic Ion Channels

Abstract

The ganglion cells of the vertebrate retina form the pathway by which the retina communicates with the visual cortex. The ganglion cells convert the graded potentials into a pattern of spikes whose characteristics are modulated by the synaptic and membrane currents. Voltage-clamp studies of retinal ganglion cells have identified voltage- or ion-gated currents, which appear to play a role in generating spikes [1]. In previous studies, the ionic conductances have been modeled by means of deterministic differential equations similar to the Hodgkin-Huxley formulation [2, 3]. Recently, however, it was suggested that the stochastic properties of ionic channels are critical in determining the reliability and accuracy of neuron firing [4]. It is important, therefore, to clarify the relationship between membrane excitability and channel stochastics in retinal ganglion cells.