TEMPERATURE CHANGES IN THE CORTEX AND HYPOTHALAMUS DURING SLEEP

Abstract

Local brain temps. of un-anaesthetized cats were followed by means of thermocouples placed in known regions. The temp. of the hypothalamus, normally above that of cortex, increased in semi-rhythmic bursts during activity, and especially in rage or fear; it was diminished and stabilized during sleep. The specific cooling of the hypothalamus during sleep is due to lowered cell metabolism rather than to marked changes in blood flow. This indicates a decreased rather than an increased activity of the hypothalamic "sleep center" during sleep.