Fig. 1. Recording of the ventilatory rhythm at room temperature, at hyperthermic failure, and at recovery of ventilatory motor pattern generation in the locust. (A) Simultaneous recording of the temperature of the superfusing saline at the MTG (Temp) and the ventilatory motor pattern recorded from muscle 161 in the second abdominal segment (M161). Areas marked B-E are shown in expanded form below. (B) A section of the ventilatory rhythm during the first 20 min while the preparation was allowed to stabilize at room temperature. (C) Heat-induced failure of motor pattern generation. The arrow indicates where failure of motor patterning was determined. The burst of electrical activity following hyperthermic failure of the rhythm is typical and usually marks the cessation of all electrical activity. (D) Post-stress recovery of the ventilatory rhythm. The arrow indicates where recovery of the rhythm was determined. (E) The rhythm returns to normal shortly following recovery. (F) Expansion of bursts displaying intraburst activity. Mean ventilatory frequencies were obtained by calculating the inverse of the cycle period (1/P) for all bursts and calculating the average of these values.