Memory Modulation by the Predictive and Preparatory Functions of Aversive Conditioned Stimuli

Lapointe, Thomas
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University of Guelph

A well-learned conditioned stimulus (CS) acts both as a predictive signal, indicating that a biologically significant stimulus (i.e., US) is about to occur, and elicits preparatory reactions required to respond to the anticipated US. The goal of the current research was to explore the psychological functions of CSs that make them effective in facilitating memory consolidation. Male Sprague-Dawley rats trained on a signalled active avoidance task could be divided in “avoider” and “non-avoider” sub-groups. Sub-group differences in avoidance were maintained during a test carried out in the absence of the US. Moreover, the “non-avoider” sub-group displayed significant stress-induced analgesia (hot-plate test) immediately after this test, suggesting significant sub-group differences in conditioned emotionality. However, immediate post-sample exposure to the avoidance context & CS had a similar enhancing effect on object memory in the two sub-groups. Therefore, this research demonstrates that both the predictive and preparatory function of CSs have important roles in modulating memory consolidation.

Conditioned stimulus, memory consolidation, active avoidance, individual differences, rat