Figure 3.1.

Cortical-BG-thalamic models. (A) The “standard” model. Green arrows, excitatory (glutamatergic) projections; Red circles, inhibitory (GABAergic) projections; Blue arrows, dopaminergic projections. (+) and (−) indicate excitatory and inhibitory effects of dopamine on MSNs, respectively. Abbreviations are defined in the text. (B) Updated model. Not all connections described in the text are illustrated for clarity. (C) Model emphasizing thalamic circuits. Roman numerals indicate cortical layers. Ovals in layer V indicate distinct populations of IT and PT neurons. Note the distinct projection patterns of the cerebellar and BG-recipient thalamus. In the thalamus, “BG” and “Cer” indicate the BG and cerebellar-recipient regions, respectively. Circular arrows in (B) and (C) indicate candidate oscillation generators. Figure and caption reprinted with modification from Ellens and Leventhal (2013), copyright 2013, with permission from IOS Press.