Subthalamic nucleus output

Descending output of the globus pallidus to other components of the basal ganglia is directed principally to the subthalamic nucleus and to the entopeduncular nucleus (internal segment of the globus pallidus in primates) and the substantia nigra (Haber... 

There are two other distinctive features of striatal output organization. The first is the segregation of the projections of the patch-matrix compartments of the striatum. This will be discussed in a later section. The second, which has been mentioned, is the dual projection zones of striatal inputs in both the globus pallidus and substantia nigra. As will be described these dual projection systems appear also in the organization of other components of the basal ganglia, including the projection of the subthalamic nucleus. 

Fig. 33. A diagram of the model of Parkinson s disease that suggests that dopamine (DA) depletion in the disease results in an elevated output of the indirect pathway (enkephalin, ENK, D2 containing neurons), which results in increased excitatory input from the subthalamic nucleus (stn) to the internal globus pallidus (GPi) and substantia nigra and a decreased output of the direct pathway (substance P SP, D1 containing neurons). See text for further details.

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