The lower limb flexion reflex in humans.

摘要: The flexion or flexor reflex (FR) recorded in the lower limbs humans (LLFR) is a widely investigated neurophysiological tool. It polysynaptic and multisegmental spinal response that produces withdrawal of stimulated limb resembles (having several features common) hind-paw FR animals. FR, both animals humans, mediated by complex circuitry modulated at supraspinal level. At rest, LLFR (usually obtained stimulating sural/tibial nerve recording from biceps femoris/tibial anterior muscle) appears as double burst composed an early, inconstantly present component, called RII reflex, late, larger stable RIII reflex. Numerous studies have shown afferents mediating are conveyed large-diameter, low-threshold, non-nociceptive A-beta fibers, those small-diameter, high-threshold nociceptive A-delta fibers. However, afferents, including fibers skin muscles, been found to contribute activation. Since threshold has correspond pain size be related level perception, it suggested might constitute useful tool investigate processing level, pharmacological modulation pathological conditions. As stated EFNS guidelines, most used all reflexes, reliable assessment treatment efficacy. use clinical evaluation neuropathic still limited. In addition its nocifensive function, seems linked posture locomotion. This may explained fact neuronal circuitry, made up pool interneurons, interposed motor control and, during movements, receives peripheral (flexion FRAs) descending commands, forming multisensorial feedback mechanism projecting output motoneurons. excitability, this finely state- phase-dependent manner, rather we observe animal models. Several demonstrated excitability influenced numerous physiological conditions (menstrual cycle, stress, attention, sleep so on) states (spinal lesions, spasticity, Wallenberg's syndrome, fibromyalgia, headaches on). Finally, drugs neurotransmitters. summary, study proved interesting functional window onto mechanisms neural operating