Cutaneous temperature and unit activity in the hypothalamic thermoregulatory centers

Multiple and single unit activity has been recorded in the preoptic/anterior hypothalamic nuclei of rats anesthetized with urethane. Two groups of neurons have been identified within the medial and lateral regions of the rostral hypothalamus which exhibit changes in their spontaneous discharge frequencies in a similar manner to the frequency characteristics of either “warm” or “cold” cutaneous thermoreceptors. It is suggested that the change in frequency of discharge of these neurons may represent the neural correlate of the downward setting of the hypothalamic thermostat that occurs when the animal is exposed to elevated environmental temperatures.