What makes Parkinson’s disease distinctive from other movement disorders is that cell loss occurs in a very specific region of the brain called the substantia nigra (sub-STAN-she-uh NYE-gruh). The nerve cells, or neurons, in this region actually appear dark under a microscope (substantia nigra is Latin for “black substance”).

Those dark neurons produce a specific type of neurotransmitter (a chemical messenger that allows neurons to communicate) . The neurotransmitter helps to regulate movement. This loss of neurotransmitter is the reason that many treatments for Parkinson’s Disease are intended to increase its levels in the brain.

In addition to decreases in neurotransmitter and the cells that make them, you might also read or hear about alpha-synuclein (AL-fa-sin-NUKE-lee-un). We do not yet know what this protein does in the healthy brain, but in Parkinson’s disease it clumps up in what are called Lewy (LOO-ee) bodies. Researchers believe that alphasynuclein build-up contributes to the cause of Parkinson’s disease and that it may be possible to develop new treatments based on this idea.