PONTINE LESIONS PRODUCE APNEUSIS IN THE RAT

Although lesion experiments in the vagotomized cat have indicated that neurons in the parabrachial region of the dorsolateral pens contribut e to the mechanisms involved in terminating inspiration, a similar rol e for pontine structures in the rat has been questioned since pontomed ullary transections in the anesthetized rat failed to prolong inspirat ion. In the present study, lesions of the parabrachial pens of the dec erebrate, unanesthetized rat produced an increase in the duration of i nspiration to 400% of control and a doubling of the duration of expira tion, suggesting a role for this pontine area in the regulation of the timing of the phases of respiration.