(a) Representative images (Golgi-Cox staining) of distal Purkinje cell dendrites in the distal molecular layer (DML), quantification of spine density (WT, n=97/4, dendrites per mice; Shank2−/−, n=89/4, P=0.2, MWU-test) and cumulative frequency plots of spine length (P=0.4, MWU-test) and thickness (P=1, MWU-test) in WT (n=748/4 spines per mice) and Shank2−/− mice (n=639/4) as indicated. Scale bar, 1 μm. (b,c) Representative images (electron microscopy) of spine synapses in the DML and cumulative frequency plots of PSD length (WT, n=226/4, PSDs per mice; Shank2−/−, n=243/4, P=0.3) and thickness (WT, n=223/4; Shank2−/−, n=233/4, P=0.9) as indicated. Scale bar, 100 nm. (d) Biochemical analysis of Shank2 (WT, n=12 synaptosomes; Shank2−/−, n=6), GluA1 (WT, n=12 synaptosomes; Shank2−/−, n=6, P=0.041) GluA2 (WT, n=11; Shank2−/−, n=5, P=0.014) and Nlgn3 (WT, n=12; Shank2−/−, n=6, P=0.4) in cerebellar synaptosomes from WT and Shank2−/− mice as indicated. Data in bar graphs are presented as mean±s.e.m.; single asterisks indicates P<0.05. Two-sided t-tests were used, unless stated otherwise.