The differential involvement of the prelimbic and infralimbic cortices in response conflict affects behavioral flexibility in rats trained in a new automated strategy-switching task.
Résumé
To assess the role of the prelimbic (PL) and infralimbic (IL) cortices in mediating strategy switching, rats were trained in a new automated task in a Y-maze allowing a careful analysis of rats' behavior. In this situation, rats can only use two egocentric (Right, Left) and two visual (Light, Dark) strategies. In the first experiment, rats with PL, IL, or PL/IL lesions were compared with sham-operated rats when trained to reach a criterion of 10 consecutive correct responses with a light strategy before being trained with a response strategy (rule shifting), and finally with the reversed response strategy (reversal). In the second experiment, sham-operated and PL-lesioned rats had their first two strategy switches in the reverse order, which was followed by a second rule shifting and reversal. The results indicate that lesions did not affect initial acquisition, but impaired the first rule shifting and reversal. Thorough analyses of rats' performance indicate that lesioned rats were still able to demonstrate some behavioral flexibility but have difficulties in solving response conflicts, which in turn may affect behavioral flexibility. Both areas were differentially involved in the resolution of response conflict, with the IL involved in the choice of strategy previously known to be nonvalid, and the PL in the selection and maintenance of that strategy.