Vestibular inputs to bulbar respiratory interneurons in the cat

Vestibular inputs to medullary respiratory interneurons were studied in decerebrated and artificially ventilated cats. Extracellular recordings were made from 40 neurons located in the area of pre-Bötzinger complex and activated antidromically from the contralateral ventral respiratory group. Neuronal populations analyzed included inspiratory and expiratory neurons with augmenting, constant and decrementing firing patterns, and a late inspiratory neuron. Seventeen neurons responded to ipsilateral and/or contralateral vestibular nerve electrical stimulation. These responses were observed in all seven cell types. Most neuronal reflex responses consisted of inhibition, while a few consisted of either excitation or a combination of both inhibition and excitation. These results indicate that pre-Bötzinger respiratory interneurons, which may be involved in respiratory rhythmogenesis, also participate in vestibulorespiratory responses.