title: The external globus pallidus: progress and perspectives.
abstract: The external globus pallidus (GPe) of the basal ganglia is in a unique and powerful position to influence processing of motor information by virtue of its widespread projections to all basal ganglia nuclei. Despite the clinical importance of the GPe in common motor disorders such as Parkinson's disease, there is only limited information about its cellular composition and organizational principles. In this review, recent advances in the understanding of the diversity in the molecular profile, anatomy, physiology and corresponding behaviour during movement of GPe neurons are described. Importantly, this study attempts to build consensus and highlight commonalities of the cellular classification based on existing but contentious literature. Additionally, an analysis of the literature concerning the intricate reciprocal loops formed between the GPe and major synaptic partners, including both the striatum and the subthalamic nucleus, is provided. In conclusion, the GPe has emerged as a crucial node in the basal ganglia macrocircuit. While subtleties in the cellular makeup and synaptic connection of the GPe create new challenges, modern research tools have shown promise in untangling such complexity, and will provide better understanding of the roles of the GPe in encoding movements and their associated pathologies.
authors: Department of Physiology, Feinberg School of Medicine, Northwestern University, Chicago, IL, 60611, USA.
authors: Daniel J
authors: DJ
authors: Hegeman
authors: Department of Physiology, Feinberg School of Medicine, Northwestern University, Chicago, IL, 60611, USA.
authors: Ellie S
authors: ES
authors: Hong
authors: Department of Physiology, Feinberg School of Medicine, Northwestern University, Chicago, IL, 60611, USA.
authors: Vivian M
authors: VM
authors: Hernández
authors: Department of Physiology, Feinberg School of Medicine, Northwestern University, Chicago, IL, 60611, USA.
authors: C Savio
authors: CS
authors: Chan
mesh_terms: D000818:Animals; D001479:Basal Ganglia / Q000502:physiology / Q000503:physiopathology; D001927:Brain Diseases / Q000503:physiopathology; D005917:Globus Pallidus / Q000502:physiology* / Q000503:physiopathology; D006801:Humans; D009068:Movement; D009434:Neural Pathways / Q000502:physiology / Q000503:physiopathology; D009474:Neurons / Q000502:physiology*; D020531:Subthalamic Nucleus / Q000502:physiology / Q000503:physiopathology
keywords: Npas1; Parkinson's disease; arkypallidal neurons; parvalbumin; prototypic neurons