H-Reflexes in Normal Human Infants: Depression of These Electrically Induced Reflexes (EIR's) in Sleep

Abstract

I. Three H-reflexes, 2 of which have not been described previously, have been obtained in 13 normal human neonates when the ulnar nerve was stimulated. These electrically induced reflexes (EIR's) were demonstrated by muscle action potential recordings from the flexor muscles of the forearm (UFEIR), the hypothenar (UHEIR) and the first dorsal interosseus muscles (UIEIR) of the hand. 2. The UFEIR had a lower threshold than either the UIEIR, or the previously described UHEIR. 3. All 3 EIR's were reduced in amplitude in neonates and in those subjects reexamined 2 to 4 months later, as the infants fell asleep. They were restored by spontaneous arousal or by waking induced by sensory stimulation with sound, light, or touch.