APP and psychiatric disorder: Furthermore, in transgenic mice capturing some pathology of a neurological or psychiatric disease and showing cognitive impairment power of elicited hippocampal theta is significantly reduced, including the beta-amyloid peptide (Aβ) overproducing amyloid precursor protein (APP)/PS1transgenic mice, tau-transgenic mice and NMDA receptor hypomorphic mice (Scott et al., 2011, 2012; Kiss et al., 2013).