ISOLATION DISRUPTS RETENTION IN PREWEANLING RAT PUPS

Expression of an olfactory memory in Is-day-old rat pups was examined in eight experiments following brief manipulations of environmental co nditions prior to a retention test. In the first experiment we found t hat retention was disrupted if a pup was placed in isolation for 3 hr prior to the retention test. The retention deficit persisted even when pups had 3-hr exposure to an anesthetized dam and siblings before tes ting. However, there was no defrcit in retention if pups spent the pre test interval with a nonlactating foster dam, their father, or litterm ates. Finally, we found that this deficit in retention could be allevi ated by cuing treatments that preceded the retention test following is olation. Both discrete cues used during training and returning the pup to the home cage with parents and siblings for 3 hr were found to all eviate the retention deficit caused by isolation. These data demonstra te that housing conditions can influence postacquisition memory proces ses in the young animal.