Cellular and synaptic properties of molecularly defined neurons in the external globus pallidus

Linda M C Koene; Wilhelm Thunberg; Sten Grillner; Gilad Silberberg; Maya Ketzef

doi:10.1016/j.isci.2025.113002

Cellular and synaptic properties of molecularly defined neurons in the external globus pallidus

iScience. 2025 Jun 27;28(8):113002. doi: 10.1016/j.isci.2025.113002. eCollection 2025 Aug 15.

Authors

Linda M C Koene¹, Wilhelm Thunberg¹, Sten Grillner¹, Gilad Silberberg¹, Maya Ketzef¹

Affiliation

¹ Department of Neuroscience, Karolinska Institutet, 171 77 Stockholm, Sweden.

Abstract

The external globus pallidus (GPe) is a central basal ganglia (BG) nucleus, involved in various sensorimotor functions. The two main types of GPe neurons, the prototypic and arkypallidal neurons, differ in developmental origin, axonal projections, and functional roles. Using ex vivo whole-cell patch-clamp recordings, we characterized the membrane properties, morphology, and synaptic connectivity of molecularly identified GPe neurons. Arkypallidal neurons had broader, slower action potentials with higher thresholds, and smaller somata, dendritic length, and surface area than prototypic neurons. Optogenetic activation of prototypic neurons inhibited both GPe subpopulations, but paired recordings revealed very sparse direct synaptic connectivity only between prototypic neurons. Moreover, parvalbumin-expressing prototypic neurons were not electrically coupled. This work provides a comprehensive description of the GPe microcircuitry and may provide insight into the functional role of the GPe within the BG network.

Keywords: Cell biology; Cellular neuroscience; Neuroscience; Physiology.