Fig. 4

Exposure to underwater trauma following knockdown of TrkB in the BLA significantly increased prevalence of affected individuals and impaired fear extinction memory without affecting the conditioning of fear. a Total distance traveled in the open field arena and anxiety index of distance did not differ between the CTR (n = 8), CTR-UWT(n = 15) and TrkBKD-UWT (n = 15) groups. b Total distance moved and anxiety index of distance in the elevated plus maze significantly differ between the CTR, CTR-UWT and TrkBKD-UWT groups. c Behavioral profiling based on anxiety-like behavior in OF and EPM revealed an increased proportion of ‘affected’ rats in the trauma-exposed groups (CTR-UWT & TrkBKD-UWT) compared to the CTR group. Values are the % ‘unaffected’ and ‘affected’ animals in each group. d Acquisition of fear to the auditory conditioned stimulus (CS) paired with shock, measured as % freezing to the CS, did not differ between CTR (n = 8), CTR-UWT (n = 15) and TrkBKD-UWT (n = 15) groups three groups (e) Freezing difference during the extinction training showed reduced level for freezing in CTR compared to trauma exposed (CTR-UWT & TrkBKD-UWT) groups (f–h) Total freezing (%) was gradually decreased from day 1 to day 3 in CTR animals compared to trauma-exposed animals. Data are shown as means ± SEMs, *p < 0.05, **p < 0.01, ***p < 0.001