CONTEXTUAL INFORMATION ENHANCES OBJECT MEMORY RETENTION VIA HIPPOCAMPAL-PREFRONTAL INTERACTIONS

Contextual information provides a structural scaffold for memory integration, allowing new experiences to be linked with prior knowledge. However, the neural mechanisms supporting item-context associations are still poorly understood. In this study, we investigated how contextual structure influences the retention of hippocampus and mPFC-dependent object recognition memory (ORM) in male and female Wistar rats. Using a brief training protocol, we found that learning in a familiar, feature-free context resulted in a short-term ORM that decays after a few hours. In contrast, when learning occurred in a familiar, feature-rich context, a long-term, context-dependent ORM was formed. This memory depends on ventral hippocampal-prelimbic communication, as it was abolished by optogenetic inhibition of this pathway during training. Moreover, long-term ORM was not observed when hippocampal-prelimbic projections were chemogenetically inhibited shortly after habituation or when habituation occurred in a different arena. These findings support the hypothesis that contextual structures can shape memory consolidation and that hippocampal-mPFC interactions are crucial in this process.