E. Top: schemas illustrating the behavioral tasks in 5-HT6-/- mice. Bottom: the plots represent the discrimination index for the novel object recognition test (discrimination index: 0.30 ± 0.05, N=10 and 0.31 ± 0.03, N=11, for THC+Vehicle and Vehicle+Vehicle conditions, respectively, p > 0.05), the 3-chamber social preference test (sociability index: 0.49 ± 0.04, N=10 and 0.48 ± 0.07, N=11 for THC+Vehicle and Vehicle+Vehicle conditions, respectively, p > 0.05) and the social discrimination test (discrimination index: 0.15 ± 0.06, N=8 and 0.21 ± 0.06, N=8 for THC+Vehicle and Vehicle+Vehicle conditions, respectively, p > 0.05), measured in each condition. One-way ANOVA followed by Bonferroni test (error bars correspond to the mean ± SEM, the dotted line corresponds to a discrimination index equal to zero). 