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The minimal F wave latency is typically 25-32 ms in the upper extremities and 45-56 ms in the lower extremities. F wave persistence is the number of F waves obtained per the number of stimulations, which is normally 80-100% (or above 50%).
The upper motor neurons are thought to inhibit the reflex arc, which is formed by sensory neurons from intrafusal fibers of muscles, lower motor neurons (including alpha and gamma motor fibers) and appurtenant interneurons. Therefore, damage to lower motor neurons will subsequently result in hyporeflexia and/or areflexia. [citation needed]
In neuroscience and motor control, the degrees of freedom problem or motor equivalence problem states that there are multiple ways for humans or animals to perform a movement in order to achieve the same goal. In other words, under normal circumstances, no simple one-to-one correspondence exists between a motor problem (or task) and a motor ...
Knee jerk or patellar reflex — a kick caused by striking the patellar tendon with a tendon hammer just below the patella, stimulating the L4 and L3 reflex arcs. Moro reflex , a primitive reflex — only in all infants up to 4 or 5 months of age: a sudden symmetric spreading of the arms, then unspreading and crying, caused by an unexpected ...
Hyperreflexia is overactive or overresponsive bodily reflexes. Examples of this include twitching and spastic tendencies, which indicate disease of the upper motor neurons and the lessening or loss of control ordinarily exerted by higher brain centers of lower neural pathways. [citation needed] Spinal cord injury is the most common cause of ...
Others involve lower brain areas and can be influenced by prior instructions or intentions, but they remain independent of perceptual processing and online control. The simplest reflex is the monosynaptic reflex or short-loop reflex, such as the monosynaptic stretch response.
Phenol injections or botulinum toxin [4] [5] injections into a muscle belly of the upper or lower extremities can be used to attempt to dampen the signals between nerve and muscle. The effectiveness of medications varies between individuals, and varies based on location of the upper motor neuron lesion (in the brain or the spinal cord).
Babinski reflex: The plantar aspect of the foot is gently stimulated in a line starting a few centimeters distal to the heel and extended to a point just behind the toes, and then turned medially across the transverse arch. This is done slowly over 5-6 seconds.