ABSTRACT
OVERVIEW The basal ganglia comprise a set of subcortical nuclei that include the putamen (PT), globus pallidus interna (GPi), globus pallidus externa (GPe), subthalamic nucleus (STN), substantia nigra pars compacta, and substantia nigra pars reticularlis. However, the basal ganglia are integral parts of a larger system, which includes at the minimum, the supplementary motor area, motor cortex (MC), and ventorlateral and ventroanterior thalamus, as these structures are interdigitated among the nuclei traditionally associated with the basal ganglia. When viewed physiologically, in terms of propagation of information, the functional systems are far more extensive. Hence, there is little sense in discussing the physiology or pathophysiology of the basal ganglia alone. Rather, the physiology and pathophysiology of the basal ganglia-thalamic-cortical system (and beyond) should be discussed.
