Behavioral tagging as a mechanism for aversive-memory formation under acute stress

LOPES DA CUNHA PAMELA; TINTORELLI, RAMIRO; CORREA, JULIETA; BUDRIESI, PABLO; VIOLA HAYDEE

Congreso; 35th Annual Congress of Argentine Society of Neuroscience; 2020

The Behavioral Tagging hypothesis (BT) postulates that a weak learning experience, that only induces short-term memory, can be benefited from another event that provides the plasticity-related products (PRPs) to establish a lasting memory. According to BT, the weak learning sets a transient neural-tag at specific activated sites; thus, LTM would be formed by the temporal and spatial convergence of this learning-tag and the PRPs. Also, BT proposes that the tags set by different tasks located in a common population of neurons could compete for the available PRPs.In this work, we focused on studying how an extrinsic stressor affects the formation of an aversive memory, analyzing the results under the BT framework. Rats were subjected to a weak inhibitory-avoidance training (wIA) and we observed that stress (elevated platform) experienced 1 hour before wIA promoted IA-LTM formation. This effect was dependent on glucocorticoid-receptor activity as well as protein synthesis in the dorsal hippocampus. However, the same stress impaired the LTM induced by a strong IA-training. Since this negative effect was reverted by a novel-OF exploration, a PRP-provider event, a competence for PPRs utilization could be taking place. Finally, it was demonstrated that stress immediately after IA-training does not prevent the setting of learning-tag, but it also promotes IA-LTM formation. These findings reveal that acute stress could impact on IA-LTM formation through the processes of BT.