Rothwell, J.C., Day, B.L., Berardelli, A. et al. Exp Brain Res (1984) 54: 382. doi:10.1007/BF00236241
The effect of a descending corticospinal volley on a spinal inhibitory pathway, has been studied in five intact human subjects. Approximately 63% inhibition of the H-reflex evoked in wrist and finger flexor muscles, was produced by motor threshold stimulation of the radial nerve. When a submotor threshold cortical shock was given 2 to 4 ms before the H-reflex, this inhibition was reduced to approximately 38%. The timing of this effect is compatible with either a monosynaptic or disynaptic corticospinal tract projection onto the spinal inhibitory interneurone.
Cortical stimulation Ia inhibition H-reflex Spinal cord Human