Active dendrites enhance neuronal dynamic range

TL;DR

This paper demonstrates that active dendritic conductances significantly enhance neuronal dynamic range, producing highly non-linear responses and double-sigmoid functions, which are crucial for neuronal computation.

Contribution

It introduces a model showing that active dendrites increase dynamic range and produce experimentally observed response functions, highlighting their functional importance.

Findings

Active dendrites produce highly non-linear responses with large dynamic range.

The model replicates double-sigmoid response functions seen in retinal ganglion cells.

Blocking active conductances reduces neuronal dynamic range.

Abstract

Since the first experimental evidences of active conductances in dendrites, most neurons have been shown to exhibit dendritic excitability through the expression of a variety of voltage-gated ion channels. However, despite experimental and theoretical efforts undertaken in the last decades, the role of this excitability for some kind of dendritic computation has remained elusive. Here we show that, owing to very general properties of excitable media, the average output of a model of active dendritic trees is a highly non-linear function of their afferent rate, attaining extremely large dynamic ranges (above 50 dB). Moreover, the model yields double-sigmoid response functions as experimentally observed in retinal ganglion cells. We claim that enhancement of dynamic range is the primary functional role of active dendritic conductances. We predict that neurons with larger dendritic trees should have larger dynamic range and that blocking of active conductances should lead to a decrease of dynamic range.