Deep brain stimulation: Anatomical, physiological, and computational mechanisms

INTRODUCTION—THE ALBIN AND DELONG MODELModern understanding of the basal ganglia (BG) dates to the Albin and DeLongmodel, which proposed a functional relationship between the nuclei of the BG[striatum, pallidum, substantia nigra, and subthalamic nucleus (STN)] (1,2). Inthis model, the BG controls the initiation and execution of motor programsthrough the interplay of the direct and indirect projection pathways, both ofwhich originate in the striatum (Fig. 1A). According to the model, activation F1of the direct pathway results in inhibition of pallidal output and consequentdisinhibition of thalamocortical projection neurons. Activation of the indirectpathway results in excitation of the internal segment of the globus pallidus