Aversive olfactory avoidance and shock reactivity in aged flies. (A) Olfactory avoidance indices (A.I.) for Oct at the odor concentration used for training and testing (0.12%) of w(CS10) flies at 2, 10, 20, 30, and 50 d of age. (B) Olfactory avoidance indices for Ben at the odor concentration used for training and testing (0.05%) of w(CS10) flies at 2, 10, 20, 30, and 50 d of age. (C) Shock avoidance at the voltage used for olfactory conditioning (90 V) of w(CS10) flies at 2, 10, 20, 30, and 50 d of age. Data were evaluated via Tukey post hoc following significant differences after one-way ANOVA (n ≥ 10 for all groups; *P < 0.05, **P < 0.0001). All error bars indicate SEM.