Taste learning and memory: a window on the study of brain aging.

Taste aversion learning exhibits advantages for research on memory brain systems and its reorganization throughout life. A review of the effects of aging on taste memory abilities offers a complex picture showing preserved, impaired, and enhanced functions. Some of the age-related changes in taste memory seem to be associated with an altered temporal processing. Longer taste-illness delays can be introduced for acquisition of conditioned taste aversions and the modulation of taste learning by the temporal context is absent in naïve old rats. It is suggested that an altered hippocampal function is involved in the peculiar performance of these rats. Evidence is also presented which suggests that hippocampal-dependent taste memory can be reactivated by previous learning experiences in old rats. Results obtained after reversible inactivation of the dorsal Hippocampus by tetrodotoxin (TTX) in old rats support such a view. Therefore, the interaction between the previous experience and acute brain interventions should be taken into account when studying the effect of aging on taste memory.