On the Integration of Subthreshold Inputs from Perforant Path and Schaffer Collaterals in Hippocampal CA1 Pyramidal Neurons

Using a realistic model of a CA1 hippocampal pyramidal neuron, we make experimentally testable predictions on the roles of the non-specific cation current, Ih, and the A-type Potassium current, IA, in modulating the temporal window for the integration of the two main excitatory afferent pathways of a CA1 neuron, the Schaffer Collaterals and the Perforant Path. The model shows that the experimentally observed increase in the dendritic density of Ih and IA could have a major role in constraining the temporal integration window for these inputs, in such a way that a somatic action potential (AP) is elicited only when they are activated with a relative latency consistent with the anatomical arrangement of the hippocampal circuitry.