Figure 3.

In this experiment, males and females were exposed to the stressful event, and 24 h later, trained on the classically conditioned eyeblink response using a trace paradigm that is dependent on the hippocampal formation for acquisition (Beylin et al. 2001; Wood et al. 2001). Exposure to the stressful event increased the number of learned responses in males, but reduced the number of learned responses in females, especially when they were tested in proestrus. There are also sex differences in conditioning itself, with females outperforming males under unstressed conditions. Overall, these data indicate that males and females can respond in opposite directions to the same environmental event.