Cognition in female transmembrane domain neuregulin 1 mutant mice

Neuregulin 1 (Nrg1) has been implicated in the development of schizophrenia and influences key neurodevelopmental processes such as myelination and neuronal migration. The heterozygous transmembrane domain Nrg1 mutant mouse (Nrg1 TM HET) exhibits a sex-specific phenotype relevant for schizophrenia research, which is characterized by the development of locomotor hyperactivity, social withdrawal, and changes to the serotonergic system. Cognitive impairments are characteristic of schizophrenia patients and male Nrg1 TM HET mice exhibit cognitive deficits in novel object recognition and contextual fear conditioning. Thus, we investigated the cognitive performance of female Nrg1 mutants, using a cognitive test battery for a variety of paradigms, including fear conditioning, cheeseboard, Y maze, object exploration and passive avoidance. Female Nrg1 mutant mice displayed impairments in the fear conditioning tasks, including significantly reduced fear conditioning to a context and a strong trend towards a decreased ability for cue fear conditioning. These cognitive deficits were task-specific, as no differences were seen between mutant and control mice in spatial learning of the cheeseboard for reference memory measures, in the Y-maze for working memory measures, or in novel object recognition and passive avoidance paradigms. These findings indicate that neuregulin 1 plays only a minor role in cognition in female test mice. The current study provides a further behavioural validation of this genetic mouse model for the schizophrenia candidate gene neuregulin 1 and confirms the importance of considering female test animals in animal models for schizophrenia.