Females displayed heightened anxiety following CUS as assessed in the open field test. (A, C) In females, CUS produced a significant stress effect in the duration of time in the open field (F1,45 =4.06, p<0.05) as well as in the frequency to enter the center area (F1,45 =6.33, p<0.05). CUS in the BDNF KOs resulted in a significant decrease in duration of time in the center (p<0.05) and in the number of entries in the center (p<0.05) compared to nonstressed BDNF KOs. (B, D) Male mice did not differ in their anxiety behavior before or after stress regardless of genotype.