Memory is differently impaired during aging according to the learning tasks in the rat

The aim of the present study was to determine the impact of aging on learning and retrieval of taste-potentiated odor aversion (TPOA). TPOA, which involves processing of odor, gustatory, and visceral cues, is a particular form of learning important to food selection. The experiment was carried out on young (1.5 month), adult (12 months), and old (20-24 months) rats. To determine whether the possible effects of aging on TPOA were related or not to general memory alterations, mnesic abilities of the rats were previously evaluated by submitting the animals to object recognition, olfactory discrimination, and spatial homing task. It was noted that the young, the adult, and the old rats were able to learn and to retrieve TPOA whatever the stimulus - either odor or taste - used to elicit retrieval. Interestingly, it can be underlined that the rejection of the odor stimulus only was even slightly increasing with the rat age. Thus, TPOA which is important in food selection and in animal survival is spared during aging while mnesic deficits were observed in the other behavioral tasks tested according to the task requirement.