What Is an Upper Motor Neuron?
An upper motor neuron is a neuron, or nerve cell, that exists in the brain and sends higher-level motor information to the medulla, located in the brain, or to the correct spinal cord level outside of the brain. From the medulla or the spinal cord, lower motor neurons carry motor information to muscle fibers, making them much more directly responsible for movement than upper motor neurons. One can find an upper motor neuron in a couple of different parts the the brain. Upper motor neurons are generally concentrated in the motor region of the brain stem or cerebral cortex; they send motor information downward from there.
