Substantia Nigra

The substantia nigra is a group of neurons in the brain located in the midbrain and is responsible for the production of dopamine. Dopamine signals the basal ganglia which is responsible for control of movement and the initiation of moving. The substanstia nigra is composed of two parts: the substanstia nigra pars compacta and the substanstia nigra pars reticulata. Parkinson's disease (hyperlink?) is caused by the ceasing of function of the dopamine neurons in the substanstia nigra pars compacta. This is why symptoms of Parkinson's include problems with movement. The related symptoms are tremors, difficulty initiating movement, rigidness, and moving slowly. Drugs like L-DOPA can be used to 'replace' the dopamine that is no longer produced by the substanstia nigra and can help greatly with Parkinson's symptoms.