Reciprocal inhibition in cerebral palsy.

We studied reciprocal inhibition by recording the changes in firing probability of single motor units of the tibialis anterior muscle following stimulation of low-threshold afferents in the posterior tibial nerve. In 15 patients with cerebral palsy, the inhibition was as great or greater than normal. We found no evidence that group I afferents produce "reciprocal facilitation" in cerebral palsy.