The acquisition of temporally proximate information can impair the brain’s ability to consolidate earlier experiences, resulting in retroactive interference (RI). Recognition-based behavioral paradigms are well-suited for investigating RI in rodents, particularly those involving sequential learning episodes. The medial prefrontal cortex (mPFC) integrates multimodal information relevant to the regulation of memory interference and is strongly modulated by the serotonergic system. Serotonin 2A receptors (5-HT2AR), which are densely expressed in the mPFC, have been shown to influence the retrieval of competing object-recognition memories. However, their role in other phases of memory processing, particularly in modulating RI, remains unclear. Using a modified version of the object recognition task designed to induce RI, combined with pharmacological manipulation of 5-HT2AR, we demonstrate that RI specifically impairs the object-related component of memory. Moreover, serotonin signaling through 5-HT2AR is necessary to prevent RI. Strikingly, activating 5-HT2AR before retrieval can rescue the expression of memories affected by RI, suggesting that RI may not erase memory traces but rather hinder their access.

Synchronization of sharp-wave ripples across the dorsoventral hippocampus during sleep supports coordinated reactivation that represents negative experiences more faithfully than positive ones.

Synchronization of sharp-wave ripples across the dorsoventral hippocampus during sleep supports coordinated reactivation that represents negative experiences more faithfully than positive ones.

The integration of spatial and emotional components into episodic memory relies on coordinated interactions between hippocampal circuits and emotion-processing regions. While the dorsal hippocampus (d...