CX3CR1 deficiency cause cognitive impairment. Transient global cerebral ischemia resulted in increased mean swim latency in the cued learning task (A), discrimination learning task (B), and delayed non-matching-to-sample task (D) compared to the sham control group. Ischemic rats also made more error in the discrimination learning task (C) and delayed non-matching-to sample task (E) when compared to the sham control animals. However, CX3CR1 deficiency in the ischemic rats exacerbated their impaired behavioral performance in the cued learning, discrimination learning, and delayed non-matching-to-sample task. CX3CR1 deficiency in the sham rats also resulted in impaired behavioral performance in the three cognitive tasks.*P <0.05 and **P <0.01.