(A) Social-fear conditioning (SFC) on day 1 is followed by extinction learning protocol in homecage, 24 hours later, on day 2.
(B) Heatmaps of the time exploring stimulus mice in homecage during extinction trial 1 and 6 on day 2. The dashed circle represents the stimulus box holding the stimulus mice.
(C) Time exploring stimulus mice on day 2 if no electric footshock was applied on day 1 (SFC−). Bold lines indicate means±SEM, light lines individual subjects (N). Two-way ANOVA: Effect of trials × genotype F(5,50)=7 p<0.0001, effect of genotype F(1,10)=0.1 p=0.7, effect of trials F(5,50)=2 p=0.12.
(D) Time exploring stimulus mice on day 2 if at least one footshock was applied when exploring the stimulus mouse on day 1 (SFC+). Two-way ANOVA: Effect of trials × genotype F(5,115)=5.1 p=0.0003, effect of genotype F(1,23)=13.9 p=0.001, effect of trials F(2.7,62)=28.5 p<0.0001. Bold lines indicate means±SEM, light lines individual subjects (N).
(E) Time exploring stimulus objects on day 2 of the SFC− group. Bold lines indicate means±SEM, light lines individual subjects (N). Two-way ANOVA: Effect of trials × genotype F(2,24)=2.8 p=0.17, effect of genotype F(1,12)=0.005 p=0.08, effect of trials F(2,24)=0.15 p=0.08.
(F) Time exploring stimulus objects on day 2 of the SFC+ group. Bold lines indicate means±SEM, light lines individual subjects (N). Two-way ANOVA: Effect of trials × genotype F(2,42)=0.8 p=0.4, effect of genotype F(1,21)=0.3 p=0.5, effect of trials F(2,42)=4.3 p=0.02.
(G) Proportion of mice discriminating between the stimulus mice by ≥ 20% of exploration time (Chi2
p<0.0001).
(H) Time exploring a novel stimulus mouse on day 3, to test recall of extinction memory (means±SEM). Two-way ANOVA: Effect of SFC × genotype F(1,32)=4.2 p=0.04, effect of genotype F(1,32)=0.32 p=0.5, effect of SFC F(1,32)=14.1 p=0.0007. Post-hoc Tukey’s test, * p=0.001.
(I) Time of freezing immediately post-conditioning (means±SEM). Two-way ANOVA: Effect of SFC × genotype F(1,31)=0.2 p=0.6, effect of genotype F(1,31)=0.7 p=0.4, effect of SFC F(1,31)=83.4 p<0.0001. Post-hoc Tukey’s test, *** p<0.0001.