Changes in exploratory behavior in male Lister-Hooded rats in early and late adulthood

Exploration encompasses a range of behaviors aimed at gathering information about the environment, which is then encoded and stored in memory. Memory processes support exploration by retaining past experiences, facilitating habituation to novelty, and aiding in the formation and updating of cognitive maps. As aging often leads to changes in memory function, we expected these changes to be detected by analyzing exploratory behaviors. In our experiment, we investigated the behavior of male rats at 2 and 9 months of age. We found that young rats reacted to novel objects with greater intensity and spent more time in the zone where change was introduced. In addition, they moved between the zones more frequently than the older ones. There were no differences in habituation rate, and the reaction to novelty was typical for both ages. However, older rats exhibited higher grooming levels and spent more time in the starting box. The results indicate that basic memory functions are not impaired in older rats, but the level of emotional reactions is slightly elevated compared with measures taken at a young age, which may influence their performance and lead to decreased exploratory behavior. Our findings also suggest that the rats can retain memory traces of events that occurred months earlier and show familiarity with the experimental environment. Our research indicates that behavioral changes associated with memory decline in older individuals may be linked to alterations in emotional regulation. These changes appear to have a neurobiological foundation centered on the hippocampus, where distinct regions process anxiety responses alongside memory functions. (PsycInfo Database Record (c) 2026 APA, all rights reserved).