Coupling between respiratory and locomotor rhythms during fictive locomotion in decerebrate cats.

Fictive locomotion of the hindlimb was evoked by stimulation of the mesencephalic locomotor region (MLR) in immobilized, decerebrate cats. Fictive respiration can also be obtained in such a preparation after bilateral vagotomy. A cross-correlation technique was used to evaluate the strength of the coupling between the locomotor and respiratory rhythms. This study demonstrated that there was a locomotor-respiratory coupling of central origin and the strength of the coupling varied depending on the level of end-tidal pCO2, reflecting the arterial CO2 tension.