INSPIRATORY-PHASE SHORT TIME SCALE SYNCHRONY IN THE BRAINSTEM SLICE IS GENERATED DOWNSTREAM OF THE PRE-BOTZINGER COMPLEX

Abstract Respiratory neurons are synchronized on a long time scale to generate inspiratory and expiratory-phase activities that are critical for respiration. Long time scale synchrony within the respiratory network occurs on a time scale of more than hundreds of milliseconds to seconds. During inspiration, neurons are synchronized on a short time scale to produce synchronous oscillations, which shape the pattern of inspiratory motor output. This latter form of synchrony within the respiratory network spans a shorter time range of tens of milliseconds. In the neonatal mouse rhythmically active medullary slice preparation, we recorded bilateral inspiratory activity from hypoglossal (XII) rootlets to study where in the slice synchronous oscillations are generated. Based on previous work that proposed the origin of these oscillations, we tested the pre-Botzinger complex (PreBotC) and the XII motor nucleus. Unilateral excitation of the PreBotC, via local application of a perfusate containing high K + , increased mean inspiratory burst frequency bilaterally (296±66%; n =10, P P P n =10) and oscillation power in the ipsilateral (50±17%, n =7, P