Parkinson’s disease affects nerve cells in a part of the brain called the basal ganglia. The basal ganglia control movement and balance in the body. Inside the basal ganglia are nerve cells, which produce a brain chemical called dopamine. Dopamine takes "messages" about movement from cell to cell in the brain. These messages in the brain tell the rest of the body how to move. In Parkinson’s disease, the cells that produce dopamine gradually die off. This alters the processing of information about movement in the brain, which is why someone suffering from Parkinson's disease may have trouble moving.
Normal dopamine-producing nerve cells in the brain—Messages travel normally
Loss of dopamine-producing nerve cells in Parkinson's disease—Fewer messages reach nerve cells
