Balancing Consistency and Flexibility: Exploring trait and state optimism in rats using the cognitive judgement bias test

Each test was conducted on three consecutive days. It comprised three different locations ("Negative", "Positive" and "Ambiguous") which were shown several times ("Measurement") and the latency to approach these locations was recorded.

Then, we exposed the rats to either negatively valenced 22 kHz or positively valenced 50 kHz USV playbacks ("Treatment") to manipulate state optimism and tested them again for their optimism levels. Lastly, we conducted tests for anxiety-like behavior to assess whether the manipulation was accompanied by broader changes consistent with altered emotional state. The following parameters were recorded: Elevated Plus Maze: Time spent on open arms, entries to open arms; Open Field: Distance travelled, time spent in the center zone, entries to the center zone; Dark Light Box: Latency to enter open area, entries to open area, time in open area.