Substantia Nigra

The substantia nigra is a brain structure which is part of the basal ganglia. It is made up of neurons and plays an important role in movement and addiction. The substantia nigra consists of two parts with very different connections and functions; the pars compacta and pars reticulata. The pars compacta serves mainly as an input to the basal ganglia circuit and supplies the striatum with dopamine. The pars reticulata, on the other hand, serves mainly as an output, conveying signals from the basal ganglia to numerous other brain structures.

The destruction of the substantia nigra is associated with Parkinson's disease. Parkinson's disease's is a neurodegenerative disease caused by the death of dopaminergic neurons in the pars compacta of the substantia nigra. The cause of death of dopaminergic neurons in the pars compacta is unknown.