FIG. 3.

A: schematic of network module illustrating inactivation of the I-Driver population by inhibition (perturbation 4—circled) and subsequent application of external excitatory drive to both I-Aug and I-Dec populations (perturbation 5—circled). B: elimination of I-Driver activity terminated both network oscillations and phrenic activity. Subsequent increased excitation of the I-Aug and I-Dec populations (an additional excitatory drive to these populations) re-established network oscillations and a normal rhythmic phrenic output. Vertical dashed line indicates truncation of period without rhythm.