motor pathways are pathways in the brain and spinal cord that control . at least two motor neurons are present in the motor pathway: an upper motor neuron and a lower motor neuron. the cell body of an motor neuron is housed either within the cerebral cortex or a nucleus within the brain stem. axons of these synapse either directly on motor neurons, or on . the cell body of a lower motor neuron is housed either within the horn of the spinal cord or within a brainstem cranial nerve nucleus. axons of the lower motor neurons exit the cns and project to their specific effector cells.