The motor neuron system is divided into upper and lower divisions, based on whether they are in the central or peripheral nervous system. Motor neuron disease (MND) affects motor nerve cells in the spinal cord, the brain stem (which sits on top of the spinal cord), and the cerebral cortex.
UCSF Memory and Aging Center
Sandler Neurosciences Center
675 Nelson Rising Lane, Suite 190
San Francisco, California