Spatial memory deficits in Itsn mutants. A, Morris water maze. Average swimming speeds of all genotypes were indistinguishable (F_(3,43) = 2.79, p > 0.05). B, Summary of training days in the water maze revealed Itsn1^Gt/Gt and Itsn1^Gt/Gt Itsn2^−/− mice did not learn the platform location after 5 d. The results of a Genotype (Itsn1^Gt/Gt, Itsn1^Gt/GtItsn2^−/−, Itsn2^−/−, WT) × Day (1–5) ANOVA shows a significant effect of Genotype (F_(3,43) = 6.21, p < 0.05) and Day (F_(4,172) = 15.25, p < 0.001). C, During probe tests, Itsn1^Gt/Gt and Itsn1^Gt/GtItsn2^−/− mutants were unable to find the target platform. An ANOVA with the between-subjects variable Genotype and within-subjects variable Zone (Target, Others) revealed a significant interaction (F_(3,43) = 2.77, p = 0.05) as well as significant main effects of Genotype (F_(3,43) = 4.94, p < 0.05) and Zone (F_(1,43) = 15.49, p < 0.001). D, Heat map summary of Morris water maze where target zone is indicated by dotted circle. Increasing color intensity (arbitrary scale) represents increased time spent. E, During Morris water-maze probe tests, Itsn1^+/Gt were able to find the target platform as well as WT. F, Performance in contextual fear conditioning task. Itsn1^Gt/Gt and Itsn1^Gt/GtItsn2^−/− mice froze significantly less than Itsn2^−/− and WT mice, which did not differ. Mice with a mutation in Itsn1 showed impaired contextual fear memory (F_(3,44) = 6.04, p < 0.05). G, Itsn1^+/Gt mice froze to the same degree as WT mice in the contextual fear conditioning task. One-way ANOVA statistical tests were used to calculate all individual p values.