Effect of antidepressants on pessimistic judgements bias interpretation in mice exposed to chronic corticosterone: a translational touchscreen-based approach. (360G-Wellcome-212048_Z_18_Z)

Patients with depression show affective-state dependent cognitive impairments that are related with a high risk of relapse. These patients show negative bias judgements when presented with ambiguous stimuli. A novel and highly translational touchscreen-based task for evaluating this kind of cognitive bias (CB) has been developed in our lab for use in mice. We have previously demonstrated, using this task, that optimistic bias is increased following antidepressant administration. However, additional tests are needed to demonstrate the task sensitivity in detecting depressive-like phenotypes. In the present project, mice will receive a 20-day exposure to a corticosterone solution to induce a depressive-like phenotype. Following corticosterone exposure, mice will be tested on the CB task. Mice learn to approach a positive stimulus with appetitive reward, and ignore a negatively balanced stimulus with the absence of reward. Subsequently, mice will be exposed to a series of ambiguous stimuli, which they will "judge" for positive or negative valence, as indexed through their approach behaviour. If a pessimistic bias is shown, animals will be administrated the antidepressants citalopram and bupropion in order to reverse the effect.