Comparison of Discrimination Association Tasks to Test Cognitive Flexibility in Rats

Cognitive flexibility is an executive function that refers to the ability to alter behavior according to changes in one’s environment. While adolescents with a history of binge drinking have been shown to differ cognitively from abstinent adolescents, the long-term effects of adolescent alcohol exposure are largely unknown. We hypothesized that adolescent intermittent ethanol (AIE) exposed rats would demonstrate decreased cognitive flexibility in comparison to control rats. Specifically, we tested the reversal learning and set shifting ability of 80 Sprague-Dawley rats with an attentional set-shifting digging task. Our results demonstrated impaired reversal learning and set shifting abilities in AIE subjects, specifically in the second reversal. To improve the standardization of this method and further explore the long-term impact of adolescent alcohol exposure, we adapted this reversal learning protocol to an automated, operant chamber-based task. A cue was used to indicate the correct lever, and a reward was delivered if this lever was pressed. Two studies were performed, one used lights as cues and the other used tones. The rats underwent a training period to become accustomed to the box and learn the stimulus-reward associations. We found that most of the rats were able to complete the training days but were not able to reliably discriminate between the light stimuli. Subsequently, when tones were used as stimuli instead of lights, rats progressed through training faster, suggesting that tones are a more effective stimulus than lights. We conclude that our training criteria is attainable, but factors such as reward size, number of test sessions and trial criteria must be adjusted to improve acquisition performance. If acquisition performance is improved, an automated operant chamber protocol could provide valuable insight into the long-term cognitive impact of adolescent alcohol exposure.Bachelor of Scienc