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.
Structure and Function of the Upper Motor Neurons
Upper Motor Neurons have a cell body in the cerebral cortex, basal ganglia, or brainstem, and a long axon that travels down the spinal cord to synapse with LMNs. UMNs are highly branching neurons that link to numerous other neurons in the brain and spinal cord. Upper Motor Neurons are responsible for controlling voluntary movement and maintaining muscle tone. UMNs get information from numerous brain areas, such as the primary motor cortex, premotor cortex, basal ganglia, and cerebellum, which modulate their activity to generate smooth and synchronized motions.
Significance OF Upper Motor Neurons
A kind of motor neuron located close to the central nervous system. Damage or malfunction to the Upper Motor Neurons can cause a number of movement disorders, including spasticity, weakness, and loss of motor control. Stroke, severe brain injury, cerebral palsy, and multiple sclerosis are common diseases that damage Upper Motor Neurons. In these circumstances, it’s possible for the UMNs to sustain an injury, impairing communication between the brain and the LMNs and causing a loss of voluntary motor control.
Difference Upper and Lower Motor Neurons
The spinal cord’s sensory and motor pathways support the transmission of sensory and motor impulses, respectively. Motor routes take impulses from the brain and spinal cord to the muscles of the effector, whereas sensory pathways take impulses from the sense receptors to the brain and spinal cord. The two fundamental sets of neurons found in the somatic motor pathways are upper and lower motor neurons. Let’s examine the different distinctions between upper and lower neurons in this post.
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