IGF2 and Anxiety: Bdnf and Igf2 are well known to regulate anxiety behavior and fear extinction29, 30, 78, 79, 80 and are separately susceptible to glucocorticoid treatment.11, 81 Furthermore, on the basis of the strong male germline effect on behavior, Igf2 was a prime gene target as it is a well-established paternally imprinted gene, and its expression was differentially modulated in male and female F1 offspring in this study.