The Reflex Nature of the Physiological Adjustments to Diving and Their Afferent Pathway

Abstract Andersen, H. T. The reflex nature of the physiological adjustments to diving and their afferent pathway. Acta physiol. scand. 1963. 58. 263–273. — The elicitation of the submersion apnoea and bradycardia has been investigated in intact and decerebrated ducks, with and without various trigeminal lesions, in order to study the reflex nature of the diving characteristics, and to explore their afferent pathway. It has been found that the circulatory as well as the respiratory adjustments to water immersion of the head are medullary reflexes entirely independent of higher levels of the central nervous system, although the basic reflex, of course, may be influenced by activity in higher centers when the latters are intact. The trigeminal nerve is the afferent pathway of the reflex arc by which the reactions to diving are induced upon submersion. The ophthalmic division appears to be the most important branch of the V. nerve in this respect, but also the mandibular portion seems to be an element in the afferent limb of the reflex arc. The maxillary nerve, however, could not be shown to serve such a function.