Interaction between the soma and the axon terminal of horizontal cells in carp retina

In teleost retina, the receptive fields of horizontal cell axon terminals have a larger space constant than the receptive fields of the horizontal cell somata. Generally this difference in receptive field size is attributed to the cell coupling which is assumed to be stronger in the horizontal axon terminal network than in the horizontal cell soma network. The axon terminals are displaced with respect to the cell bodies. In this paper we show, using a simple simulated horizontal cell (HC) network that under the condition that the displacements are randomly distributed the difference in receptive field size between the somata and the axon terminals may be a direct consequence of this displacement. We also show that in that case it should be expected that dopamine has different actions on the somata than on the axon terminals.