ANTICIPATORY GENERAL ACTIVITY IN THIRSTY RATS

36 MALE SPRAGUE-DAWLEY RATS WERE MAINTAINED AD LIB OR ON A 23.5-HR DRINKING SCHEDULE AND UNDER CONSTANT LIGHT, CONSTANT DARK, OR NORMAL LIGHT-DARK CONDITIONS. THIRSTY SS, AS WELL AS CONTROLS, RAN MORE IN THE DARK THAN IN THE LIGHT AND MORE IN CONSTANT DARK THAN IN CONSTANT LIGHT. UNDER CONSTANT ILLUMINATION CONDITIONS, SS TENDED TO RUN IN BURSTS EVERY 25-26 HR. INDEPENDENTLY OF THIS CIRCADIAN CYCLE, ABOUT 3 OF THE THIRSTY SS SHOWED AN ANTICIPATORY BURST OF RUNNING JUST BEFORE RECEIVING THEIR DAILY WATER RATION, EVEN WHEN THERE WAS NO OVERALL INCREASE IN RUNNING. (PsycINFO Database Record (c) 2006 APA, all rights reserved). © 1968 American Psychological Association.