On the role of CaMKII in object recognition memory reconsolidation
CaMKII, Memory, Reconsolidation
Acquired information can be stabilized in long-term memory (LTM) through a protein synthesis and gene expression-dependent process called consolidation. LTM can be desestabilized when recalled and must go through a de novo protein synthesis and gene expression dependent restabilization process called reconsolidation to persist. Reconsolidation takes place in two stages and acts on an already existing mnemonic trace. The first stage, called destabilization, leaves the reactivated mnemonic trace in a malleable and modifiable state, while the second one, called restabilization, allows the mnemonic trace to become stabilized again. Object Recognition Memories (ORM) are declarative representations essential for remembering common sense information and autobiographical episodes. In fact, one of the first symptoms of Alzheimer's disease is a decline in this type of memory. The study of hippocampal synaptic proteins has been fundamental for a better understanding of the molecular mechanisms of memory in recent decades. However, the role of these proteins in ORM reconsolidation remains inconclusive. In this project, we investigated the role of hippocampal calcium/calmodulin-dependent protein kinase II (CaMKII) in ORM reconsolidation. Our preliminary results suggest that, in rats, CaMKII is not required for ORM restabilization, but plays an essential role in destabilizing ORMs. This destabilization process seems to depend on the activity of the GluN2B subunit of the N-methyl-D-aspartate receptor (NMDAr) to occur, suggesting an important regulatory interplay between CaMKII and NMDArs. In future experiments, we will analyze the participation of hippocampal CaMKII (1) in the NMDAR-dependent signaling cascades associated with ORM destabilization and restabilization and (2) in the hippocampal oscillatory profile during ORM reconsolidation. We believe that unravelling the synaptic mechanisms controlling CaMKII activation is extremely important understanding the biological properties of memory reconsolidation.