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Figure 2: T-maze Apparatus. Diagrams on the left part illustrate the mechanics of this protocol. The apparatus was divided into 6 areas (A1, A2, S1, S2, P1, P2) by sliding doors (s1, s2, s3, a1, a2, p1, p2) that the animals explored during the training sessions. Animals were placed in the star box (area s1) and allowed to explore the corresponding area according the task (forced alternation or left-right discrimination). The forced-choice run started with the doors s2, a1 and a2 in the open position. The sucrose pellet was delivered to the food compartment of the open area. The animal consumed the pellet and returned to the start box because doors p1 or p2 were closed while s1 or s3 were opened. Once completed the forced-choice run, a free choice run begun with doors s2, a1 and a2 in the open position. Animals then choose between the two arms. If the animal choice was the same than the forced choice, it was then considered and reported as "correct" choice. This procedure was repeated for 10 consecutive trials in a session per day. Once the animals completed the 80% correct response criterion, they were tested introducing a delayed alternation period of 10, 30 and 60 s between the forced and the free-choice runs. In the left-right discrimination task the animals were allowed to freely choose between left or right arms. The pellet was delivered onto the goal arm. If the animal choice was this arm, it was considered a correct response. Once the animal completed this part, it was allowed to return to the start box. The sucrose pellet was always delivered on the same arm (the goal arm). Assessment was conducted in a soundproof room provided with a close circuit camera (depicted in the right part of the figure)

Figure 2: T-maze Apparatus. Diagrams on the left part illustrate the mechanics of this protocol. The apparatus was divided into 6 areas (A1, A2, S1, S2, P1, P2) by sliding doors (s1, s2, s3, a1, a2, p1, p2) that the animals explored during the training sessions. Animals were placed in the star box (area s1) and allowed to explore the corresponding area according the task (forced alternation or left-right discrimination). The forced-choice run started with the doors s2, a1 and a2 in the open position. The sucrose pellet was delivered to the food compartment of the open area. The animal consumed the pellet and returned to the start box because doors p1 or p2 were closed while s1 or s3 were opened. Once completed the forced-choice run, a free choice run begun with doors s2, a1 and a2 in the open position. Animals then choose between the two arms. If the animal choice was the same than the forced choice, it was then considered and reported as