Basal Ganglia

About the Basal Ganglia

The basal ganglia are a group of interconnected nuclei deep within the brain, including the caudate nucleus and putamen, together called the striatum, the globus pallidus, the subthalamic nucleus, and the substantia nigra in the midbrain. They form loops with the cerebral cortex and thalamus that help select intended movements while suppressing unwanted ones, and they are involved in learning habits, reward based learning, and motivation. Dopamine released by neurons of the substantia nigra modulates these circuits. Degeneration of these dopamine producing neurons causes Parkinson disease, characterized by slowness of movement, rigidity, and tremor, while loss of neurons in the striatum causes the involuntary movements of Huntington disease. Disorders of basal ganglia circuits are also implicated in dystonia, Tourette syndrome, and obsessive compulsive disorder. Deep brain stimulation of the subthalamic nucleus or globus pallidus is an established surgical treatment for selected people with Parkinson disease.