The external pallidum: think locally, act globally.

The globus pallidus (GPe), as part of the basal ganglia, was once described as a black box. As its functions were unclear, the GPe has been underappreciated for decades. The advent of molecular tools has sparked a resurgence in interest in the GPe. A recent flurry of publications has unveiled the molecular landscape, synaptic organization, and functions of the GPe. It is now clear that the GPe plays multifaceted roles in both motor and non-motor functions, and is critically implicated in several motor disorders. Accordingly, the GPe should no longer be considered as a mere homogeneous relay within the so-called "indirect pathway". Here we summarize the key findings, challenges, consensuses, and disputes from the past few years.