Sexually dimorphic changes in the exploratory and habituation profiles of heterozygous neuregulin-1 knockout mice

The neuregulin-I gene is widely expressed in the central nervous system and is associated with increased risk for schizophrenia. Using an ethologically based approach, the phenotype of neuregulin- I heterozygous knockout mice was examined by revealing the individual elements of behaviour in the murine repertoire over the prolonged course of interaction with the environment. During initial exploration, neuregulin-I mutants displayed a phenotype characterized by increases in locomotion and rearing free, with sex-specific alterations in sifting and grooming. Over subsequent habituation, certain initial effects endured while new phenotypic effects emerged, some of which were again sex-specific. These studies elaborate a pleiotropic role of neuregulin-I in development, plasticity and function, including sexual dimorphism, by defining the elemental, temporal and sex-specific characteristics of the neuregulin-I mutant ethogram.