Fig. 3.

ELA increases corticosterone-induced negative affective bias and impairs reward-induced positive bias in the ABT and animals show impaired responses to an increase in reward in the JBT. Acute treatment with corticosterone induces a negative affective bias in rats in the ABT, with maternal separation (MS180) animals showing a greater bias at a lower dose compared to non-separated (NS) animals (a), however there was no effect of ELA on positive bias induced by the antidepressant, venlafaxine (b). MS180 animals show a significant deficit in reward-associated positive bias (c). Both MS180 and NS groups show a negative cognitive bias index (CBI) when the positive (P) cue predicts a low value of reward in the JBT (d). When the reward value is increased, NS but not MS180 animals shift towards a less negative CBI, indicating a less pessimistic judgement bias. Data represent the mean ± SEM, *p < 0.05, **p < 0.01, ***p < 0.001 vs 0% choice bias, #p < 0.05, ###p < 0.001 vs NS; n = 16/group (ABT), n = 7 per group (low reward JBT), n = 8 per group (high reward JBT)