FIG. 5.
The 2-phase rhythmic motor pattern generated by medullary preparations. Transection of the brain stem through the rostral facial nucleus (FN) transformed the normal 3-phase pattern with incrementing PN discharges (top trace) into a 2-phase pattern with square-wave-like PN discharges (2nd trace). Subsequent caudal transections (3rd trace) resulted in “ectopic” bursts—shorter duration bursts with irregular frequency and amplitude (indicated by *) interposed between longer duration square-wave bursts. Application of INaP blocker riluzole (≤10 μM concentration) eliminated ectopic bursts and stabilized the 2-phase rhythm.