Fig. 2

Sex differences in contextual fear discrimination. Mean (± SEM) percentage of freezing in Context A (shock) and Context A’ (non-shock) in males (A) and females (B). Mean (± SEM) discrimination index of the trial block 6 (Trial Day 11 + 12) (C). Mean (± SEM) percentage of freezing in males and females during the activation trial on Day 29 (D). Females exhibited significantly greater percentage of freezing in the shock-paired context (Context A) than in the neutral context (Context A’) on Trial Day 9 and Trial Day 12, whereas there was no significant difference in percentage of freezing between the two contexts in any days in males. Furthermore, females showed greater discrimination based on the index on the last trial block (Trial Day 11 + 12) compared to males. There was no significant sex difference in the percentage of freezing during the Activation Trial. *Indicates p < 0.05