Dendritic excitability primarily controls overdispersion

Abstract

A neuron’s input-output function is commonly understood in terms of the fluctuation-driven and mean-driven regimes. Here we investigate how active dendrites falling in either regime shape the input-output function and find that dendritic input primarily controls interspike interval dispersion, a prediction that is validated with dual patch clamp recordings. This phenomenon can be understood by considering that neurons display not two, but three fundamental operating regimes, depending on whether dendritic spikes or the somatic input reach threshold.