GRIN2A and schizophrenia: Mice with reduced expression of NR1 and knockout of NR2A/B subunits display behavioural abnormalities akin to those seen in PCP and ketamine models of schizophrenia, such as increased locomotion, impaired discrimination learning and stereotyped behaviour (Brigman et al., 2008; Duncan et al., 2004; Halene et al., 2009; Mohn et al., 1999; Sprengel et al., 1998).