The role of random dendrites and inhibitory pathways in retinal neuron networks

It is shown theoretically that an apparent intellectual function of direction selectivity is naturally caused by neuronal threshold dynamics in the retinal neural network with non-uniform signal delays originating in the neuron's random dendrite geometry. By addition of information pathways via inhibitory cells, the selective function is enhanced by the effect of non-isotropic shielding and temporal sharpening of neural signals. A numerical simulation of retinal neuron network demonstrates the validity of this functional improvement by addition of the inhibitory pathways.