Spontaneous alternation and spatial learning in Dab1scm (scrambler) mutant mice

Abstract Homozygous Dab1 scm mutants with cell ectopias in cerebellar cortex, hippocampus, and neocortex were compared with non-ataxic heterozygous and wild-type controls in spontaneous alternation and Morris water maze tests. Although there were no group differences in alternation rates, wild-type and heterozygote groups alternated above chance levels, whereas homozygous Dab1 scm mutants did not. In the Morris water maze, Dab1 scm mutants were impaired in both hidden and visible platform subtests. The deficits in spontaneous alternation and water maze measures reproduce the phenotype previously described in Reln rl–Orl mutants, attributed to disturbance of the same molecular pathway involving reelin.