ABSTRACT
The reorganization of the functional interconnections within and between basal ganglia regions is a necessary consequence of the phy-logenetic expansion and differentiation of the neocortex in the primate brain. The subthalamic nucleus (STN) is located in the midbrain, rostral and dorsal to the sub stantia nigra (SN). It sends projections to SN and to the internal segment of globus pallidus (GPi). The most recent target of DBS has been the STN, as this site has been found to control parkinsonian tremor as well as dystonia and akinesia. Basal ganglia, thalamic, and brainstem nuclei that are part of the seizure-generating network can, nevertheless, determine the susceptibility of other networks to enter into seizure discharge. The GABAergic neurons of SN, together with equivalent neurons in the internal segment of the GPi, comprise the output of the basal ganglia. The deep layers of the superior colliculus in the rat play an important role in nigra-evoked anticonvulsant actions.
