[Responses of bulbo-spinal neurons during the expiration reflex in cats]

Activity of 129 bulbo-spinal neurons was studied during the expiration reflex elicited by mechanical stimulation of the vocal cords or by electrical stimulation of the superior laryngeal nerve in cats under nembutal anesthesia. It was found that besides expiratory and inspiratory neurons a great number of nonrespiratory bulbo-spinal units were activated. They were localized mainly within gigantocellular tegmental fields. The results showed that expulsive expiration during this reflex was significantly provided by activation of those nonrespiratory bulbo-spinal neurons which participate also in transmission of descending effects from high-threshold afferents of other modalities.