Interestingly, although there were no significant differences in CRF1 mRNA levels between the two mouse strains, HF-ApoE4 mice showed a strong and significant correlation between CRF1 levels and the freezing percent in response to the foot shock presentation (Figure 2B; Pearson r = 0.802, **p = 0.0052), whereas HF-ApoE3 mice did not show this tendency (Figure 2C; Pearson r = 0.488, p = 0.2656), suggesting that the anxiety behavior in HF-ApoE4 mice is coordinated, at least in part, by CRF receptors in the amygdala. This evidence concerns the gene APOE and hydrops fetalis.