Dichotomous organization of the external globus pallidus.
Different striatal projection neurons are the origin of a dual organization essential for basal ganglia function. We have defined an analogous division of labor in the external globus pallidus (GPe) of Parkinsonian rats, showing that the distinct temporal activities of two populations of GPe neuron in vivo are underpinned by distinct molecular profiles and axonal connectivities. A first population of prototypic GABAergic GPe neurons fire antiphase to subthalamic nucleus (STN) neurons, often express parvalbumin, and target downstream basal ganglia nuclei, including STN. In contrast, a second population (arkypallidal neurons) fire in-phase with STN neurons, express preproenkephalin, and only innervate the striatum. This novel cell type provides the largest extrinsic GABAergic innervation of striatum, targeting both projection neurons and interneurons. We conclude that GPe exhibits several core components of a dichotomous organization as fundamental as that in striatum. Thus, two populations of GPe neuron together orchestrate activities across all basal ganglia nuclei in a cell-type-specific manner.
Medical Research Council Anatomical Neuropharmacology Unit, Department of Pharmacology and Oxford Parkinson's Disease Centre, University of Oxford, Oxford OX1 3TH, UK. np.mallet@googlemail.com
Nicolas
N
Mallet
Benjamin R
BR
Micklem
Pablo
P
Henny
Matthew T
MT
Brown
Claire
C
Williams
J Paul
JP
Bolam
Kouichi C
KC
Nakamura
Peter J
PJ
Magill
D000818:Animals; D001479:Basal Ganglia / Q000378:metabolism*; D003342:Corpus Striatum / Q000378:metabolism*; D004745:Enkephalins / Q000378:metabolism*; D005917:Globus Pallidus / Q000378:metabolism*; D009434:Neural Pathways / Q000378:metabolism; D009474:Neurons / Q000378:metabolism*; D010320:Parvalbumins / Q000378:metabolism*; D011498:Protein Precursors / Q000378:metabolism*; D051381:Rats
D004745:Enkephalins; D010320:Parvalbumins; D011498:Protein Precursors; C033660:preproenkephalin