Activity of crossed spinocerebellar tract neurones in the thoracic spinal cord in relation to the central respiratory rhythm.

Correlation between respiratory movement and neural discharges of antidromically identified 20 crossed spinocerebellar tract (SCT) neurones in the T8-11 segments was examined in the anaesthetized, paralysed cat. Activity of 11 neurones of them was related to phrenic nerve activity; 7 neurones increased and 4 decreased their activity during the active phase of the phrenic nerve. Their rhythmic activity remained even after artificial ventilation was turned off, indicating the central genesis of their rhythmic activity. By comparing discharge patterns with the ventilator on and off, it is suggested that half of these crossed SCT neurones appear to receive additional inputs from the periphery. Neurones which increased their firing rate during phrenic nerve activity tend to respond with decrease discharge to passive chest inflation, and vise versa.