Nerve cells in the substantia nigra produce the neurotransmitter dopamine and are responsible for relaying messages that coordinate body movement.
Symptoms vary from person to person as does the rate of progression.
Tremor at rest - involuntary shaking that decreases with purposeful movement. Rigidity - stiffness caused by involuntary increase in muscle tone. Postural instability - sense of imbalance, to compensate patient lowers center of gravity resulting in a stooped posture. How Your Body Moves Control of movement is a complex chain of decisions involving inter-connected groups of nerve cells called ganglia. Information comes to a central area of the brain called the striatum, which works with the substantia nigra to send impulses back and forth from the spinal cord to the brain.