Banca de QUALIFICAÇÃO: MARIA CAROLINA GONZALEZ

Uma banca de QUALIFICAÇÃO de DOUTORADO foi cadastrada pelo programa.
STUDENT : MARIA CAROLINA GONZALEZ
DATE: 07/11/2022
TIME: 16:45
LOCAL: INSTITUTO DO CEREBRO - Auditório
TITLE:

Neural mechanisms involved in object recognition memory formation, updating and integration

KEY WORDS:

BDNF; CaMKII; PKMζ; dopamine; memory recall; mnemonic networks

PAGES: 100
BIG AREA: Ciências Biológicas
AREA: Fisiologia
SUMMARY:

New memories are initially unstable and must undergo a stabilization process known as consolidation to persist. When recalled, memories can become destabilized again and a reconsolidation process is needed to re-stabilize them. Reconsolidation shares some molecular and anatomical features with memory consolidation, but they are distinct processes that seem to have specific functional roles. Because prediction error signals and novelty perceived at recall are necessary to destabilize reactivated memories, one main hypothesis is that this destabilization/restabilization cycle serves to modify and maintain the adaptive relevance of long-lasting memories. It is also known that the hippocampus is a brain region that integrates new and old memories to form networks of knowledge, but the neurobiological basis of this process remains poorly understood. 

Declarative memory is the ability to recollect knowledge, facts and events. Object recognition memory (ORM) confers the capacity to identify familiar items and discern them from novel ones, being an integral component of declarative memory and thus, essential for everyday life. In this work we studied the hippocampal neural mechanisms that underlie ORMs formation and updating in adult male Wistar rats using the novel object recognition task, an incidental learning paradigm based on the 

natural exploratory behavior of rodents. We found that while the consolidation of an object memory trace is related to CaMKII and medial septum-dependent theta activity in the hippocampus, the reconsolidation of destabilized ORMs requires PKMζ activity and Zif268 expression. We also present evidence supporting the idea that the amnesia observed after reconsolidation disruption is not due to retrieval failure, but to elimination of the mnemonic trace. Our findings also indicate that ORM destabilization is linked to dopamine signaling and theta-gamma phase amplitude coupling in the hippocampus, and that artificial induction of this oscillatory pattern can destabilize memories that are normally resistant to reconsolidation. Finally, we demonstrate that memory reconsolidation is a process that actually binds memories from different experiences, and that hippocampal D1/D5 dopamine receptors couple novelty detection to memory destabilization to control whether new memories are linked to old ones through reconsolidation or consolidated as independent memory traces instead.  

COMMITTEE MEMBERS:
Interno - 1721223 - ADRIANO BRETANHA LOPES TORT
Interno - 2069422 - DIEGO ANDRES LAPLAGNE
Presidente - 1996111 - MARTIN PABLO CAMMAROTA