Fig. 1.
A: original recordings of phrenic (PNA), vagal (VNA), and lumbar iliohypogastric nerve (L1) activity from the intact in situ perfused brain stem preparation, including the physiological response to sodium cyanide (NaCN) bolus injection of the intact preparation (B). integ., Integrated burst amplitude. C: enlarged single burst illustrates nerve discharge during phases of inspiration (I), postinspiration (PI), and expiration (E) in the intact preparation. Arrows indicate, for each nerve, the onset of nerve discharge within the respiratory cycle. D: schematic illustration of pontomedullary brain stem circuitry remaining intact following precollicular decerebration. E: Poincaré plots of respiratory cycle length (Ttot) averaged over 5 min from 9 intact preparations. Amb, nucleus ambiguus; BC, Bötzinger complex; c-rVRG, caudal and rostral ventral respiratory group; DRG, dorsal respiratory group; I5, intermediate reticular nucleus; LRt, lateral reticular nucleus; Mo5, motor trigeminal nucleus; MPB, medial parabrachial nucleus; NRA, nucleus retroambiguus; NTS, nucleus tractus solitarii; pBC, pre-Bötzinger complex; vlpons, ventrolateral pons; 7N, facial nerve.