Effects of motor cortex stimulation on spinal interneurones in intact man.
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.
D004558:Electric Stimulation; D006181:H-Reflex; D006801:Humans; D007395:Interneurons / Q000502:physiology*; D009044:Motor Cortex / Q000502:physiology*; D009433:Neural Inhibition; D011930:Reaction Time; D013116:Spinal Cord / Q000166:cytology / Q000502:physiology*