Fig. 4.
Bax deficiency affects age-related changes in behavior, cognitive function, and sensory perception. (A and B) Aged (15–17 mo) KO (−/−) females exhibit a deficit (lower freezing values) in contextual (A) but not cued (B) fear memory when compared with age-matched WT (+/+) animals (*, P < 0.001 vs. corresponding WT value). (C) Suppression ratios are comparable among genotypes in aged animals not preexposed to a CS; however, after preexposure to a CS, LI was present in aged KO but not WT females (*, P < 0.01 vs. respective NPE value). (D) In response to 120 dB, aged WT females exhibit a markedly decreased ASR compared with young adult (2–3 mo) WT mice (*, P < 0.001), whereas no significant change in ASR is detected in KO females with age. (E) In young adult WT and KO females, the percent PPI as a function of prepulse intensity is comparable at all three prepulses; however, aged KO mice exhibit a maintenance of PPI compared with their aged WT littermates (*, P < 0.05 vs. corresponding WT response). (F) The ASR to a wide range of startle intensities in aged WT (filled circles) and KO (open circles) female mice (*, P < 0.05 vs. corresponding WT value). Data are the mean ± SEM with 9–17 mice per group.