Illustration of Charcot?s disease. This disease is the result of motor neuron degeneration. Motor neurons are nerve cells that work as control units and communication links between the nervous system and voluntary muscles. Motor neurons located in the brain (superior motor neurons) transmit nerve impulses to motor neurons in the spinal cord (inferior motor neurons) , as well as to particular muscles. With Charcot?s disease, the superior motor neurons (bulbar) and inferior motor neurons (spinal) degenerate or die, and stop sending impulses to the muscles. The muscles are incapable of functioning and gradually weaken and atrophy.