Tuberomammillary nucleus activation anticipates feeding under a restricted schedule in rats

We used FOS-immunoreactivity to map changes in the neuronal activity of brain nuclei related to the state of arousal, in rats under a restricted feeding schedule. Our main finding was the outstanding activation of the tuberomammillary nucleus 24 h after a meal, and its steep deactivation, which was independent of actually having the meal. The time course of FOS activation and deactivation indicated a bu rst of tuberomammilary nucleus activity in close temporal relation with the increased locomotor activity shown by rats in anticipation of the next meal. (C) 2000 Published by Elsevier Science Ireland Ltd.