The Hungry Brain: Outsmarting the Instincts That Make Us Overeat

by Stephan Guyenet

In Parkinson’s disease, the gradual loss of substantia nigra neurons causes dopamine levels to decline in the areas of the dorsal striatum that select movements, particularly well-worn movement patterns. This makes the dorsal striatum progressively less sensitive to incoming bids from motor regions, rendering it increasingly difficult for any motor option generator to gain access to the body’s muscles. People with Parkinson’s disease develop difficulty initiating and executing movements and have a particularly hard time performing sequences of movements. In severe cases, Parkinson’s disease patients are scarcely able to initiate movements at all, a phenomenon called akinesia, Greek for “no movement.”