Cell assembly dynamics of sparsely-connected inhibitory networks: a simple model for the collective activity of striatal projection neurons

TL;DR

This study demonstrates that a simplified sparse inhibitory network of Leaky-Integrate-and-Fire neurons can replicate key features of striatal neuron activity, revealing mechanisms for stimulus discrimination and implications for neurological disorders.

Contribution

A new model showing how sparse inhibitory networks produce dynamic, stimulus-specific cell assemblies, advancing understanding of striatal function and disease implications.

Findings

Network forms anti-correlated cell assemblies with time-varying activity.

Sequence of cell assembly switching discriminates similar inputs.

Altered GABAergic signaling may lead to dysfunctional network processing.

Abstract

Striatal projection neurons form a sparsely-connected inhibitory network, and this arrangement may be essential for the appropriate temporal organization of behavior. Here we show that a simplified, sparse inhibitory network of Leaky-Integrate-and-Fire neurons can reproduce some key features of striatal population activity, as observed in brain slices [Carrillo-Reid et al., J. Neurophysiology 99 (2008) 1435{1450]. In particular we develop a new metric to determine the conditions under which sparse inhibitory networks form anti-correlated cell assemblies with time-varying activity of individual cells. We found that under these conditions the network displays an input-specific sequence of cell assembly switching, that effectively discriminates similar inputs. Our results support the proposal [Ponzi and Wickens, PLoS Comp Biol 9 (2013) e1002954] that GABAergic connections between striatal projection neurons allow stimulus-selective, temporally-extended sequential activation of cell assemblies. Furthermore, we help to show how altered intrastriatal GABAergic signaling may produce aberrant network-level information processing in disorders such as Parkinson's and Huntington's diseases.