Upper: Representative images of MWM trials of the rats of four groups; Bottom: Spatial learning and memory in the MWM.

<p>Escape latency and swimming distance over 16 trials (A, C) and averaged for each day (B, D) over days 2–5. The SAH group exhibited significantly longer escape latency and swimming distance (A, C, *<i>P</i><0.01 repeated ANOVA) over the 16 trials than control groups did. The tBHQ group exhibited significantly shorter escape latency and swimming distance (A, C, #P<0.01 repeated ANOVA) over the 16 trials than the vehicle group. The averaged data showed a similar increase in escape latency (B, *<i>P</i><0.01 one-way ANOVA) in SAH animals on the fifth day relative to controls. In the tBHQ group, the averaged data exhibited significantly shorter escape latency (B, #<i>P</i><0.01 one-way ANOVA) and swimming distance (D, #<i>P</i><0.05 one-way ANOVA) on the 4th and 5th days than the vehicle group. On day 5, the relative improvement in escape latency from the previous training day was significantly lower in the SAH group than among controls (E, *<i>P</i><0.01). The tBHQ group was higher on day 4 than the vehicle group (E, & <i>P</i><0.05). The control group exhibited significantly more time saved on day 6 than in the SAH group on the working memory task (matching-to-place task), here indicated by the difference between the time required in latency to find the platform on the second (test) trial and that required to find the platform on the first (sample) trial (F, *<i>P</i><0.01). There was no significant difference between the tBHQ group and the vehicle group (values are means±SD, n = 10 per group).</p>