(A) Proportions of time aged (G4C2)66/EGFP, (G4C2)2/EGFP, and EGFP observers spent engaging in different behaviors in DIA tests. Breaks in pie charts indicate 6 minutes of omitted locomotion and social investigation behaviors.
(B-D) Total duration (B), number of bouts (C), and latency (D) of affiliative behaviors by observers towards distressed demonstrators.
(E) Total self-grooming by observers during HC1 and HC2.
(F and G) Total freezing time by observers during conditioning (F) and 24-hour retrieval (G) of OFC.
(H) Schematic of non-observation DIA paradigm.
(I) Total duration of other-directed affiliative behaviors by aged (G4C2)66/EGFP and EGFP observers during non-observational DIA tests.
Statistics: (B-E, I), two-tailed paired or unpaired Student’s t-tests. (F and G), two-way repeated measures ANOVA with Bonferroni’s post-hoc tests. *P < .05, **P < .01, ***P < .001 vs. both EGFP and (G4C2)2/EGFP, where notations indicate the least significant P values of both comparisons. ##P < .01, ###P < .001 vs. (G4C2)2/EGFP. NS, not significant. See also Figure S2 and Video S1.