Fig. 1.

Mouse medullary slice preparation containing the respiratory network. A, Extracellular suction electrodes are placed on the surface of the brain slice preparation to record population activity from the PBC. The hypoglossal motor nucleus is labeled (XII). B, PBC population activity (PBC trace) is integrated (∫PBC) and used as a marker for fictive eupneic inspiratory activity. Ci, Record of ∫PBC (top trace) and simultaneous intracellular recording from an inspiratory neuron in aCSF having 8 mm [K⁺]_o.Cii, Both population (∫PBC, top trace) and neuron bursts cease in aCSF with 3 mm[K⁺]_o. Di, Record from a different preparation than in Ci andCii shows fictive inspiratory bursts (∫PBC, top trace) and synchronized inspiratory neuron activity in aCSF having 8 mm [K⁺]_o.Dii, Note that both the population and inspiratory neuron bursts persist in aCSF with 3 mm[K⁺]_o. Calibration: (Cii) Ci–Dii, 15 mV, 10 sec.