Rostral brainstem contributes to medullary inhibition of muscle tone.

It has long been known that stimulation of the medial medulla in the decerebrate animal produces bilateral inhibition of muscle tone. In the present study we have found that transection of the brainstem at the ponto-medullary junction attenuates this inhibition. An interaction between medullary and rostal brainstem systems is responsible for the medullary inhibition phenomenon. A similar interaction may produce the inhibition of muscle tone seen in REM sleep.