Glossary
Substantia Nigra
What is the substantia nigra?
The substantia nigra is a midbrain region within the basal ganglia circuitry involved in movement and learning. Its dark appearance comes from neuromelanin, a pigment found in some of its neurons.
Substantia Nigra Structure and Function
The pars compacta contains prominent dopamine-producing neurons. The pars reticulata is mainly an output nucleus using GABA.
Movement and Parkinson's disease
Dopamine from the substantia nigra helps regulate basal ganglia circuits. The loss of dopamine-producing neurons in Parkinson's disease disrupts these circuits and contributes to movement symptoms such as tremor, rigidity, and bradykinesia, or slowed movement.
Levodopa, a precursor to dopamine, is used to reduce motor symptoms. Deep brain stimulation can also be used to alter activity in relevant circuits. Parkinson's disease involves more than this one region and more than movement symptoms.
Why it matters
The substantia nigra shows why anatomical detail matters. Its parts contribute differently to the circuits through which learning and movement occur.