Which brain structure is NOT part of the basal ganglia?

• A. Caudate Nucleus
• B. Cerebellum
• C. Putamen
• D. Subthalamic Nucleus

Answer: (B)

The basal ganglia are a set of deep gray matter structures involved in initiating and modulating movement, forming loops with the cortex and thalamus. Major components include the caudate nucleus and putamen (together called the striatum) and the subthalamic nucleus, as well as the globus pallidus and substantia nigra. The cerebellum, while essential for coordination and timing, sits outside this system and connects with motor areas through separate cerebello-thalamo-cortical pathways. So the structure not part of the basal ganglia is the cerebellum. The other options are all canonical parts of basal ganglia circuitry.