Impaired auditory fear conditioning in McGill-Thy1-APP transgenic rats. Freezing responses in a-c) 3 month-old and d-f) 13 month-old transgenic rats. Following two days of habituation and animal handling, auditory fear conditioning was tested (a, d) followed by assessment of contextual fear conditioning 24 h later (b, e). The following day (48 hs after auditory conditioning), cued fear responses were examined in a different arena (c, f). Note the progression of auditory and contextual fear conditioning deficits as the amyloid pathology advanced from pre- to post-plaque stages. a, c, d, f) Two-Way ANOVA, followed by Bonferroni post-hoc test. b, e) One-Way ANOVA, followed by Bonferroni post-hoc test. Error bars represent mean ± SEM. *P < 0.05, **P < 0.01, ***P < 0.001.