NRG1 and schizophrenia: Neuregulin-1 and ErbB4 mouse models have been extensively studied for functional and behavioral studies since they show schizophrenia-related behaviors (Stefansson et al., 2002; Golub et al., 2004; O’Tuathaigh et al., 2007) including hyperactivity in the open field, defects in the Prepulse Inhibition (PPI) and deficits in fear conditioning and extinction (Stefansson et al., 2002; Golub et al., 2004; O’Tuathaigh et al., 2007; Chen et al., 2008, 2010; Mei and Xiong, 2008; Shamir et al., 2012).