Open field exposure facilitates recovery from an aversive emotional event: Involvement of adrenergic and cholinergic transmitter systems

Abstract

Successive negative contrast (SNC) is an incentive relativity procedure that has been widely used to model emotional reactivity in rodents. The reward downshift experienced during SNC is thought to result in frustration. The exploration of a novel open field (OF), a complex situation involving stress induction and novelty detection, can enhance or block the acquisition of associative and non-associative memories. Previous experiments found a modulatory effect of OF, applied before downshift trials, on SNC. This schedule, however, can affect retention performance by influencing attentional, motivational, motor or sensory-perceptual mechanisms at training or retention testing. The use of post-training OF exposure avoids these confounds. This work assessed the effect of OF exposure after the acquisition of the downshifted memory, with the goal of targeting the consolidation of this mnemonic trace. We also investigated the involvement of the cholinergic and adrenergic systems in this phenomenon. The results indicated that OF facilitates recovery from reward loss and that both transmitter systems, cholinergic and adrenergic, play a role in this effect of OF.

Keywords: Adrenergic; Cholinergic; Emotional memory; Frustration; Novelty; Open field.