Figure 1: Effect of TMT on the spontaneous alternation behavior (A) and number of neurons in the hippocampal DG (B and C). (A) Mice were injected with a single dose of TMT (2 mg kg−1), and subjected to the spontaneous alternation test in the Y-maze every day for 8 days after the day of TMT injection. The ordinate shows the total alternation opportunities (total arm entries, a) and percentage alternation (b) for 8 min in each test. The values (the mean ± SE; n = 3–5) obtained 2 or 8 days after the treatment were significantly lower than the original value, determined by one-way ANOVA with Tukey's test, *P <  .05 and **P <  .01, respectively. (B) Photographs of Nissl-stained hippocampal DG of mice 2 days after treatment with PBS (a), or TMT (b). Scale bar: 50  m. (C) Number of granule cells in the hippocampal DG 2 days after PBS (a) or TMT (b) treatment. The values are expressed as the mean ± SE (n = 4). The difference between the two values was determined by Student's t-test to be significant at ***P <  .001.