title: Identification of a direct GABAergic pallidocortical pathway in rodents.
abstract: Interaction between the basal ganglia and the cortex plays a critical role in a range of behaviors. Output from the basal ganglia to the cortex is thought to be relayed through the thalamus, but an intriguing alternative is that the basal ganglia may directly project to and communicate with the cortex. We explored an efferent projection from the globus pallidus externa (GPe), a key hub in the basal ganglia system, to the cortex of rats and mice. Anterograde and retrograde tracing revealed projections to the frontal premotor cortex, especially the deep projecting layers, originating from GPe neurons that receive axonal inputs from the dorsal striatum. Cre-dependent anterograde tracing in Vgat-ires-cre mice confirmed that the pallidocortical projection is GABAergic, and in vitro optogenetic stimulation in the cortex of these projections produced a fast inhibitory postsynaptic current in targeted cells that was abolished by bicuculline. The pallidocortical projections targeted GABAergic interneurons and, to a lesser extent, pyramidal neurons. This GABAergic pallidocortical pathway directly links the basal ganglia and cortex, and may play a key role in behavior and cognition in normal and disease states.
authors.affiliation: Department of Neurology, Beth Israel Deaconess Medical Center and Harvard Medical School, 3 Blackfan Circle, CLS 717, Boston, MA, 02115, USA.
authors.forename: Michael C
authors.initials: MC
authors.lastname: Chen
authors.forename: Loris
authors.initials: L
authors.lastname: Ferrari
authors.forename: Matthew D
authors.initials: MD
authors.lastname: Sacchet
authors.forename: Lara C
authors.initials: LC
authors.lastname: Foland-Ross
authors.forename: Mei-Hong
authors.initials: MH
authors.lastname: Qiu
authors.forename: Ian H
authors.initials: IH
authors.lastname: Gotlib
authors.forename: Patrick M
authors.initials: PM
authors.lastname: Fuller
authors.forename: Elda
authors.initials: E
authors.lastname: Arrigoni
authors.forename: Jun
authors.initials: J
authors.lastname: Lu
mesh_terms: D000818:Animals; D005260:Female; D059330:GABAergic Neurons / Q000166:cytology* / Q000502:physiology; D005917:Globus Pallidus / Q000166:cytology* / Q000502:physiology; D008297:Male; D051379:Mice; D017072:Neostriatum / Q000166:cytology; D009434:Neural Pathways / Q000166:cytology / Q000502:physiology; D056347:Neuroanatomical Tract-Tracing Techniques; D017397:Prefrontal Cortex / Q000166:cytology* / Q000502:physiology; D051381:Rats; D017207:Rats, Sprague-Dawley
keywords: GABA; basal ganglia; frontal cortex; globus pallidus