Open field activity is linked to, but is not affected by, the rate of recovery from reward downshift in female Wistar rats.

ABSTRACT

Frustration is an aversive emotion triggered by unexpected reward downshifts. Using the consummatory successive negative contrast (cSNC) task, a 32-to-2% sucrose downshift was shown to initially suppress consummatory behavior. Such suppression was followed by behavioral recovery over subsequent sessions. Individual differences often emerge in the rate of recovery after the initial consummatory suppression. These experiments were designed to determine whether a stable trait of sensation/novelty seeking (SNS) is related to such individual differences in recovery from reward downshift. In Experiment 1, open field (OF) activity in the central area served as a measure of SNS. A week later, animals received training in the cSNC task involving ten 5-min sessions of access to 32% sucrose followed by four sessions of access to 2% sucrose. Higher OF activity predicted greater consummatory suppression after downshift, but a steeper recovery rate across downshifted sessions. Controls not exposed to the OF showed cSNC, but downshifted animals performed at equivalent levels whether they had OF exposure or not. In Experiment 2, after a 32-to-2% sucrose downshift, fast vs. slow recovery animals displayed similar levels of central activity in the OF. In Experiment 3, animals exhibited similar levels of central activity whether after a 32-to-2% or an 8-to-2% sucrose downshift. In both experiments, activity levels were similar whether immediately after session 12 (onset of recovery) or after session 15 (fully recovered). These results suggest that individual variations in recovery from reward downshift are correlated with levels of SNS as a stable trait.