Abstract
Some anticipatory response in several behavioral and physiological activities are known to occur before the start of the feeding time when rats are kept to eat during the restricted time of day. In order to examine an anticipatory response in feeding behavior, we devised a special cage with a touch sensor in front of the feed bin that could detect a rat approaching to the feed bin. When the rat was fed ad libitum under a 12-hr light-dark cycle, the approach activity was high during the dark phase, reflecting a nocturnal feeding habits of rats. When the rat was restricted to eat for 4-hr in the daytime, the approach activity was higher in the daytime, and a burst of the approach activity was found before the start of the feeding time. The increase in the approach activity was observed even under starvation during the expected feeding time for several days. A similar effect of restricted feeding was also found under a constant lighting condition. It was concluded that, when rats were fed regularly once a day, hey could learn the feeding time and come to anticipate the daily feeding. This anticipation takes the form of greatly increased approach to the feed bin before the feeding time.
