What is the source of the major output of the basal ganglia?
The primary basal ganglia output arises from GPi and SNr.
The GPi and SNr bear many similarities and are often regarded as a functional unit separated during development by the internal capsule.
The output neurons from the GPi and SNr to the thalamus are mainly GABAergic and innervate the mediodorsal and ventral tier thalamic nuclei (which provide feedback to the frontal cortex), the intralaminar thalamic nuclei (which provide feedback to the striatum), the superior colliculus (important in the control of the ocular movements), and the pedunculopontine nucleus (involved in the maintenance of posture).
