THE ORIGIN OF RESPIRATORY ACTIVITY PATTERNS

Abstract

A fundamental question of motor integration of the respiratory act is raised[long dash]Are the configurations of the activity patterns of the respiratory contractions of centro-genic origin or are they of reflexogenic origin depending upon periodic proprioceptive drives accompanying each phase of the respiratory act? The answer is sought in a study of activity patterns before and after elimination of periodic proprioceptive signals by complete curare paralysis. The existence of the characteristic slowly augmenting inspiratory discharge in the phrenic nerve during complete curare paralysis indicates that this type of discharge is of centrogenic origin for it occurs without the aid of periodic proprioceptive impulses. Conclusions regarding the expiratory discharges are more involved for there are 2 patterns to consider. The persistence of only the steady state discharge in the motor nerves of the expiratory muscles during curare paralysis indicates that the recurrence of this discharge is of centrogenic origin for it likewise occurs without the aid of proprioceptive impulses. The rapidly augmenting type of expiratory discharge, found in the absence of motor paralysis and during lighter anaesthesia, is tentatively interpreted as a reflex modification of the steady state discharge.