The lower motor neuron (LMN) is the efferent neuron of the peripheral nervous system (PNS) that connects the central nervous system (CNS) with the muscle to be innervated. The entire function of the CNS is manifested through the lower motor neuron.Click to see full answer. In this way, what is a lower motor neuron?Lower motor neuron: A nerve cell that goes from the spinal cord to a muscle. The cell body of a lower motor neuron is in the spinal cord and its termination is in a skeletal muscle. The loss of lower motor neurons leads to weakness, twitching of muscle (fasciculation), and loss of muscle mass (muscle atrophy).Similarly, what is the difference between an upper and lower motor neuron? The nerves that send messages between the cerebral cortex and the spine are called upper motor neurons, and those that relay messages from the spine to the muscles are called lower motor neurons. Moreover, what is the definition of motor unit? A motor unit is made up of a motor neuron and the skeletal muscle fibers innervated by that motor neuron’s axonal terminals. Groups of motor units often work together to coordinate the contractions of a single muscle; all of the motor units within a muscle are considered a motor pool.Where are the lower motor neurons located?Overview. Skeletal (striated) muscle contraction is initiated by “lower” motor neurons in the spinal cord and brainstem. The cell bodies of the lower neurons are located in the ventral horn of the spinal cord gray matter and in the motor nuclei of the cranial nerves in the brainstem.