NRG1 and Cognitive impairment: NRG-1 or erbB4 knock out mice exhibit schizophrenia-like behaviors such as disruption of PPI, latent inhibition and cognitive deficits (Stefansson et al., 2002; Falls, 2003; Hashimoto et al., 2004; Rimer et al., 2005; O’Tuathaigh et al., 2007).