Stress affects predictive learning in a contextual fear memory

Congreso; XXXIV Congreso anual de la Sociedad Argentina de Investigación en Neurociencias.; 2019

Poster 134. A growing amount of evidence has shown that consolidated fear memories can enter a transient labile phase under certain conditions. Prediction error, defined as the discrepancy between an expectation and what the organism experiences is crucial for triggering the destabilization/reconsolidation process. On the other hand, stress facilitates the formation of a fear memory resistant to destabilization. However, the role of stress on prediction error has not been investigated. The goal of the present study was to investigate the effect of stress on the temporal prediction error in contextual fear conditioning in rats. The results suggest that stress affects the temporal prediction error related to the unconditioned stimulus arrival. As expected, Midazolam (MDZ) interferes with memory reconsolidation in control rats. In contrast, stressed rats displayed a fear memory resistant to the MDZ?s disruptive effect. Given that d-cycloserine (DCS, NMDA receptor partial agonist) facilitates memory destabilization, we next investigated the effect of pre-reactivation DCS combined with post-reactivation MDZ on fear memory reconsolidation in stressed rats. DCS restored vulnerability to MDZ disruptive effect but fail to recover the temporal prediction error about the arrival of the unconditioned stimulus. This effect was not observed in DCS stressed rats injected with vehicle. Fear learning under highly arousing events limits the occurrence of temporal prediction error during reactivation.