5-HT2a receptor in prefrontal cortex participates in the resolution of retroactive interference between object memories during consolidation

FACUNDO MORICI; GALLO, FRANCISCO T.; MAGDALENA MIRANDA; BEKINSCHTEIN, PEDRO; NOELIA V WEISSTAUB

Lisboa

Simposio; Champalimaud Research Simposium; 2018

Champalimaud Center for the Unknown

Historically, memory consolidation was associated the activity of the medial temporallobe. However, in recent years, it was shown that the Prefrontal cortex (PFC) alsoplays a role, particularly when interfering information is presented. The serotoninergicmodulation of PFC has been linked with attentional and executive processes. Though,little is known about the role of serotoninergic modulation of PFC during theconsolidation of interfering memory traces. The object-in-context memory task (OIC) isa recognition protocol in which two object-context associations are generated. Then,depending on the strength of the memory traces, interference between both memoriescould occurred. Since PFC serotonin type 2a receptor (5-HT2AR) activity has beenshown to help prevent memory interference during retrieval, we wanted to evaluate if itcould participate in the control of memory interference during consolidation. Weselectively modulated PFC 5-HT2AR activity after OIC-memory acquisition. Weobserved that activation of 5-HT2AR was required for the resolution of the OIC taskonly when the training protocol generated a weak OIC-memory trace that could not beretrieved 24 hs later. However, blockade of 5-HT2AR did not affect the OIC-memoryconsolidation when animals generated a long-lasting memory. Moreover, the PFC 5-HT2AR activity seemed to be required only when two memory consolidation processeswere triggered within a specific time window. Our results suggest that the PFC 5-HT2AR activity might help to disambiguate competing memory traces in a time andstrength dependent way.