Effect of intra-CA1 inhibition of NR2B-NMDARs on delayed-alternation T-maze task. (A) Diagram showing the delayed-alternation performance in T-maze task. In the initial trial, both the left- and right-arm of the maze is baited and rats could get food by entering into either of them. From trial 1 on, rats have to avoid the arm visited in the previous trial and enter into the opposite arm in order to get reward. Inter-trial interval (delay period) is 0, 5, or 30 seconds. (B) Rats with intra-CA1 infusion of Ro25-6981, ifenprodil, or NVP-AAM077 made significantly more errors compared with the control rats in T-maze performance with 5-s or 30-s delay. **p<0.01 vs. the vehicle control, Mann-Whitney U-test.