Brain
Basal Ganglia
Movement gating, habit, and reward
Overview
The basal ganglia are a group of nuclei deep within the cerebral hemispheres, including the striatum (caudate nucleus + putamen), globus pallidus, subthalamic nucleus, and substantia nigra. They regulate movement initiation, suppress unwanted movements, support habit formation, and are central to the brain's reward system.
Function
- Initiation and suppression of voluntary movements
- Procedural learning and habit formation
- Reward-based learning via dopamine signals
- Selection of appropriate actions and filtering irrelevant ones
- Modulation of cognitive and emotional behaviors
Key Facts
- Parkinson's disease results from dopamine-neuron loss in the substantia nigra
- Huntington's disease destroys striatal neurons progressively
- Deep brain stimulation of subthalamic nuclei treats advanced Parkinson's
- The basal ganglia do not connect directly to the spinal cord