Analysis of a postsynaptic scheme based on a tapering equivalent cable model

An analytic solution of a modified cable equation with reversal potentials is used to explore nonlinear synaptic effects in passive dendritic trees of arbitrary geometry. It is shown that shunting inhibition can be effective when located off the direct path between the excitation and the soma. It is also shown that a peripherally placed excitatory input juxtaposed with a shunting inhibitory input may produce a voltage-peak minimum at the soma in order to suppress the initiation of an action potential at the axon hillock. The applicability of this postsynaptic scheme as a basis for a directionally selective signal generation in the retina is discussed.