Schematic and simplified synopsis of the brain regions and pathways involved in tremorogenesis. See text for details. (D1, Dopamine receptor type 1; D2, dopamine receptor type 2; exc., excitatory; GABA, γ-amino butyric acid; Glu, glutamate; GPe, external globus pallidus; GPi, internal globus pallidus; ICP, inferior cerebellar peduncle; inh., inhibitory; SCP, superior cerebellar peduncle; SNc, substantia nigra, pars compacta; SNr, substantia nigra pars reticulata; STN, subthalamic nucleus; VIM, ventrointermediate nucleus of thalamus.)