Figure 2.

Assessment of hippocampus-dependent learning and memory abilities after 15 minutes of global cerebral ischemia and after OE-MSC transplantation. Cognitive abilities of rats were assessed in the olfactory associative task 4 weeks after surgery. (a) Mean percentage of correct responses, (b) intertrial interval, and (c and d) latencies were obtained during 6 training sessions of 40 trials per day. Ischemic rats (n = 12) exhibited significant impairment in an associative memory task when compared with control rats (n = 8). The ischemia group was randomly divided between grafted (n = 6) and sham (n = 6) groups, and learning and memory abilities of rats were assessed 5 weeks after transplantation of OE-MSCs or culture medium. Performances obtained by control rats (n = 8) in session 6 served as the reference for the effectiveness of the memorization process. (e) Contrary to sham, grafted rats reached a percentage of correct answers comparable to control rats from day 2 and kept their high score until the end of the training sessions. The same improvement was observed for the intertrial interval (f) and latencies (g and h) only in grafted rats. ^∗p < 0.05; ^∗∗p < 0.01; ^∗∗∗p < 0.001. S−: negative scent; S+: positive scent.