Brain activity during performance of right hand movement in controls (A), as well as in PD patients (B). Abbreviations: L, left; R, right; L CB, left cerebellum; R CB, right cerebellum; L PMC, left premotor cortex; R PMC, right premotor cortex; L SM1, left sensorimotor cortex; R SM1, right sensorimotor cortex; SMA, supplementary motor area.