The external pallidum: think locally, act globally

TL;DR

This paper reviews recent discoveries about the globus pallidus externus (GPe), revealing its cellular diversity and complex roles in motor and non-motor functions, challenging traditional views of basal ganglia circuitry.

Contribution

It synthesizes recent molecular and circuit studies that uncover the GPe's cellular heterogeneity and broad connectivity, proposing new computational frameworks for basal ganglia functions.

Findings

GPe neurons exhibit diverse molecular and circuit features.

The GPe has extensive interconnectivity influencing multiple brain functions.

New models suggest complex computational roles for the GPe.

Abstract

The globus pallidus (GPe) of the basal ganglia has been underappreciated for decades due to poor understanding of its cells and circuits. The advent of molecular tools has sparked a resurgence in interest in the GPe. Here, we review a recent flurry of publications that has unveiled the complexity of the molecular landscape and cellular composition within the GPe. These discoveries have revealed that GPe neurons display a number of circuit features that do not conform to the traditional views of the basal ganglia. Consistent with its broad interconnectivity across the brain, emerging evidence suggests that the GPe plays multifaceted roles in both motor and non-motor functions. Altogether, recent data highlight cellular and functional diversity within the GPe and prompt new proposals for computational rules of the basal ganglia.