Figure 1.

STN, subthalamic nucleus; GPe, globus pallidus externus; GPi, globus pallidus internus; LHb, lateral habenula. The canonincal basical ganglia model, with an associated direct, indirect, and hyperdirect pathway. Pathways between the midbrain and striatum (nigrostriatal) for dopaminergic innervation are depicted. The reward-relevant pathway between the pallidum and LHb is also included. The tripartite hypothesis is shown for the subthalamic nucleus as an example, in which the ventromedial aspect is for limbic function, the dorsolateral aspect for motor function, and the ventrolateral aspect for associative function. See Text for more information.