Figure 5. Cognitive functions are impaired in rats after SCI. (A) Acquisition trials in Morris water maze (MWM) test. A significant difference was detected between the Sham/Vehicle (n = 11) and SCI/Vehicle (n = 17) groups at training day 4 (***P < 0.001). No differences were found between the Sham/Vehicle (n = 11) and Sham/CR8 (n = 11) groups, SCI/Vehicle (n = 17) and SCI/CR8 (n = 14) groups. (B) Probe trial in MWM test. SCI/Vehicle rats spent significantly less time in the target quadrant compared with Sham/Vehicle group (**P < 0.01) and to SCI/CR8 group (^#P < 0.05). (C) Search strategy. Systematic type is predominant in SCI/Vehicle group (64%) compared with Sham/Vehicle group (27%), whereas SCI rats with CR8 treatment displayed increased spatial type (36% vs. 25% from SCI/Vehicle rats) and reduced looping type (6% vs. 11% from SCI/Vehicle rats). (D) Representative types of search strategies. SCI rats showed less traveled distance than that in uninjured sham rats. (E) Assessment of the novel object recognition test. During the test phase, sham-injured rats showed the predicted preference for the novel object. In contrast, SCI/Veh rats had reduced preference to the novel object, and the discrimination index was 69.1 ± 5.5% for Sham/Veh (n = 11) and 28.0 ± 4.9% for SCI/Veh (n = 17, P < 0.001). CR8 treatment caused significant increase in the discrimination index (P < 0.05 vs SCI/Veh rats). (F) The passive avoidance (PA) test. There were no significant differences in the latency to enter the dark compartment in the training phase between the sham and the injured groups. Twenty-four hours after training, SCI/Vehicle rats (n = 10) spent significant less time to enter to the dark compartment compared with Sham animals (n = 11, *P < 0.05). CR8 treatment (n = 9) reversed these reduced latency (^#P < 0.05, vs. SCI/Vehicle group).