Globus pallidus external segment

There appear to be two major types of neuron cell types within the globus pallidus (Kita and Kitai 1994). One type, has a moderate to large cell soma from which radiate 

Parvalbumin positive neurons are the more abundant of the two types. 

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The topographic organization of cortical inputs to the striatum, of striatal outputs to the globus pallidus (external segment), internal segment of the globus pallidus (en-... 

In the adult brain, the D2 mRNA expression is widespread in the striatum with predominant expression within the matrix, proenkephalin indirect striatal pathway that innervates the external segment of the globus pallidus (see Graybiel and Penney, 1999). D2 mRNA expression also has a greater association with the matrix compartment during early human development (Brana et al., 1997). 

With regard to extrastriatal areas, there is distinct, but much weaker, binding in the substantia nigra, whereas other subcortical structures such as the thalamus have either no, or a very low density of, DAT. Low densities of the DAT are present in the external segment of the globus pallidus and the lateral nucleus of the amygdala (Hall et al.,... 

Shink E, Smith Y (1995) Differential synaptic innervation of neurons in the internal and external segments of the globus pallidus by the GABA- and glutamate-containing terminals in the squirrel monkey. J Comp Neurol 35S 119-141. 

Fig. 12. Diagrammatic representation of some of the connections of the basal ganglia. NC, put nucleus caudatus, putamen MC motor cortex VL ventrolateral nucleus of thalamus CM centromedial thalamus HL lateral habenular nucleus GPe, GPi external and internal segments of the globus pallidus STN subthalamic nucleus NRa, NRm dorsal and median raph6 nuclei, respectively. (Modified from Nauta and Domesick, 1979, and reproduced with their kind permission.)...

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