A potential mechanism for spontaneous oscillatory activity in the degenerative mouse retina

Abstract

Spontaneous oscillation, which does not occur in the normal retina, is observed in the retina of the retinal degeneration mutant rd1 mouse, and provides insight into some details of the retinal network. The simple model by Trenholm et al. (2012) explained a mechanism for the oscillation, but it is not clear whether this mechanism functions for a larger, real network. To explore important factors for such an oscillatory network, we constructed a computational model of the AII amacrine cell (AII-AC) network and investigated the factors that affected the AIIAC network state by the varying model parameters, such as the degree of hyperpolarization of AII-ACs, the connection range, and others. Our results revealed two major tendencies: the AII-AC network exhibited oscillation when AII-ACs were hyperpolarized sufficiently, and when the AII-AC network was made sparse. These results suggest that dysfunction of photoreceptor cells could prevent formation of the correct AII-AC network.