Role of the retrosplenial cortex in the "what" component of recognitionmemory

DE LANDETA, ANA BELÉN; KATCHE, CYNTHIA; PEREYRA, MAGDALENA; MEDINA, JORGE H.

Congreso; X Congreso Mundial IBRO 2019; 2019

Several studies demonstrated that the retrosplenial cortex (RSC) is involvedin navigation and contextual memory.Recentlyit was demonstrated that theRSCalso participatesintwo of the three recognition memory components; the?where?long-term memory (LTM) and the ?when? short-term memory (STM), but its role in the ?what" memory component remains unclear.Therefore, our work aims to elucidate theRSC requirement in the ?what? component of recognition memory. We inactivated theanterior RSC(aRSC) byGABAAagonist(muscimol, Mus)infusionsat different time-points of a non-spatial Y-maze object recognition (Y-OR) task. Our results show that the aRSC integrity is requiredfor memory consolidation and retrieval. However, the aRSC is not involved in the STM processing. As well, the aRSCrequirementin memory consolidation istimedependent, since Musinfusion immediately after sample phase produced memory deficit, but animals infused 3 h after sample phase showedintact memory.On the other hand, LTM remained intact when the aRSC was inactivated during memory acquisition. Then,we wondered whethertheaRSCinactivation during acquisition interferes with its recruitment in memory processing. Animals were subjected to a double-inactivation of the aRSC, in order to affect both acquisition and consolidation or both acquisition and retrieval.Our results showed that the first Mus infusionwould disengage the aRSC from memory processing, thus leaving consolidation and retrieval intact, despite the second infusion targeting them.In addition, weobservedan increase in c-Fos levels 1 h after the Y-OR sample phasethat is required for LTM.Our findings suggest that aRSC is required for the ?what? memory component consolidation and retrieval, but if itis not active during acquisition other brain structures may take control of memory processing.