Fig. 1

Experimental setup. A In the fixed-time schedule task, approximately 2 μL of 10% sucrose solution was delivered through the licking spout at 10 s interval. B The experimental setup of the fixed-time reversal learning task was exactly the same as that of the fixed-time schedule task, except that two drinking steel spouts were placed in front of the mouth of the animal. The distance between each licking spout was set at 4.5 mm. Sucrose solution was delivered through one of the two spouts. The rewarding spout was switched every 10 trials. The amount of sucrose solution delivered was calibrated to the same amount between each rewarding spout