Thomas M. Jessell, Howard Hughes Medical Institute Investigator, examines the neural circuits that control our movements. Neural circuits give us a glimpse of how brain wiring and circuit activity control specific behaviors, including the movement of our limbs. Consider baseball player Lou Gehrig’s remarkable hand-eye coordination, or the purity of cellist Jacqueline du Pré’s tone. Yet, both examples also remind us of the fragility of the motor system: Gehrig succumbed to amyotrophic lateral sclerosis and du Pré to multiple sclerosis. Neural circuits, sensory feedback systems and signals from the brain permit us to change motor strategies to accommodate to an ever-changing world.