NRG1 and schizophrenia: Type III Nrg1 heterozygous mice also show other endophenotypes of schizophrenia (SCZ) such as prepulse inhibition (PPI) deficits, increased ventricle volume, and altered hippocampal activity and connectivity (Wolpowitz et al., 2000; Chen et al., 2010; Nason et al., 2011) indicating a possible connection between developmental Nrg1 back signaling and cellular and behavioral endophenotypes of severe neurodevelopmental disorders such as SCZ.