Unit responses in the medulla oblongata of rabbit to changes in local and cutaneous temperature.

1. In anaesthetized rabbits which were stereotaxically implanted with a thermode following decerebellation, thermal sensitivity of neurones in the medulla oblongata to local temperature changes was examined systematically. The medullary temperature was changed by circulating water at various temperatures through the thermode. 2. Eighty-seven temperature-responsive neurones were found in the medulla, especially in the medullary reticular formation. Out of these eighty-seven, forty-eight neurones were cold-responsive neurones, while the rest were warm-responsive. Both types of neurones included not only neurones with linear or continuous relations between discharge rate and local temperature but also neurones with non-linear or discontinuous thermoresponse curves. 3. In the medulla a few of the temperature-responsive neurones showed a dynamic reaction with static discharge rate changes to changes of local temperature. 4. Seven neurones out of the fifteen respiratory neurones encountered during the exploration had thermal sensitivity to respiratory alteration of the discharge. 5. with thermal stimulation of a limited area of the skin, over 50% of the temperature-responsive neurones recorded in the medulla responded positively or negatively to changes in the skin temperature.