Figure 8: L7-Shank2^−/− mice show social impairment and signs of task-specific repetitive behaviour.

(a) Three-chamber social interaction evaluated by relative time spent in each chamber. WTs (n=16) prefer to spend time in the room with the stranger 1 mouse (S1), compared with the empty room (P=0.0002, MWU-test). (b) This was not the case for L7-Shank2^−/− (n=17) mice (P=0.7, MWU-test). (c) The preference index (S1-empty) confirms the difference between genotypes (P=0.021). (d) Following the introduction of a second stranger (S2), WTs (n=16) prefer to spend time in the chamber with S2 compared with that with S1 (P=0.0001, MWU-test). (e) The L7-Shank2^−/− mice (n=17) did not show a preference for newly introduced S2 (P=0.1, MWU-test). (f) The S1−S2 preference index indicates that WTs prefer S2 more than L7-Shank2^−/− do (P=0.013). (g) No difference was found in a marble-burying task indicative of anxious and/or repetitive behaviour (WT, n=16; L7-Shank2^−/−, n=17, P=1.0). (h) L7-Shank2^−/− (n=16) seemed to trend towards less grooming than WTs (n=13) (P=0.054). (i) T-maze paradigm showed less consecutive alternations in L7-Shank2^−/− (n=17) compared with WT (n=16) (P=0.0023, MWU-test) indicating repetitive decision-making. Data are presented as mean±s.e.m. Single and double asterisks indicate P<0.05 and P<0.01, respectively. Two-sided t-tests were used, unless stated otherwise. NS, not significant.