Difference Between Upper and Lower Motor Neurons

Upper Motor Neurons

William Gowers coined the term “upper motor neurons” (UMNs) in 1886. They are present in the cerebral cortex and brainstem and transmit information to lower motor neurons and interneurons, which in turn activate muscles directly. The primary source of voluntary movement comes from UMNs in the cerebral cortex. The bigger pyramidal cells in the cerebral cortex are these ones. In layer V of the primary motor cortex, which is located just below the cerebral cortex’s surface, are large pyramidal cells known as Betz cells. With a diameter of over 0.1 mm, Betz cell neurons have the largest cell bodies in the brain....

Lower Motor Neurons

Lower motor neurons (LMNs) are motor neurons with a motor function that are either found in the brainstem’s cranial nerve nuclei and the anterior nerve roots (cranial nerve lower motor neurons) or in the anterior grey column. Spinal lower motor neurons, which innervate skeletal muscle fibers and serve as a conduit between upper motor neurons and muscles, are essential for many voluntary actions. Lower motor neurons of the cranial nerve also help with vocalization, chewing, and some voluntary movements of the tongue, face, and eyes. Atrophy of the muscles and flaccid paralysis can result from damage to the lower motor neurons....

Difference Between Upper and Lower Motor Neurons

Upper Motor Neurons Lower Motor Neurons The central nervous system contains it totally. Either the cranial nerve nuclei in the brain stem or the grey matter of the spinal cord contain it. Upper motor neuron cell bodies are larger than lower motor neuron cell bodies. Comparatively speaking, cell bodies are smaller than upper motor neurons. According to the pathways they are using, they are categorised. Categorized according to the kind of muscle fibres they innervate. They connect with the lower motor neurons through synapses. They develop synapses with the body’s muscles. Muscle weakness and spastic hyperreflexia are symptoms of upper motor neuron lesions. Muscular atrophy, flaccid muscle weakness, fasciculation, and hyporeflexia are the effects of lower motor neuron injuries....