Neuromuscular coordination and proprioceptive control of rhythmical abdominal ventilation in intactLocusta migratoria migratorioides

Summary Within the fifth abdominal segment of intact locusts a group of dorso-ventral expiratory muscles and one inspiratory antagonist display alternating ventilatory patterns of three basic types. Accelerated movements in the dorso-ventral plane are supported by isometric activity of the intersegmental muscles which prevent extensions in the longitudinal axis.The intersegmental coupling of ventilatory motor patterns is strict during strong ventilation and loose and more metachronal with weaker pumping movements.In resting animals ventilatory rhythms are discontinuous and the long intervening pauses are interrupted by miniature inspirations only. Pumping series have a tendency to prolong the later ventilatory cycles, and interfering rhythms of different pumping types occur. Low concentrations of atmospheric CO₂ up to 3 % do not accelerate ventilatory rhythms.Afferent activity from proprioceptors could be related to ventilatory motor bursts and stimulation of the sensory nerve produces inspiratory bursts via the segmental ganglion.The neuronal mechanisms of synergistic and antagonistic muscle control as well as the segmental and intersegmental coordination and the effect of autonomous ganglionic oscillators in ventilation are discussed.