PTPN1 and Mental deterioration: Furthermore, PTP1B is up-regulated by endoplasmic reticulum (ER) stress (Agouni et al., 2011; Popov, 2012; Hakim et al., 2015), a neuronal response activated by AβOs and implicated in synapse loss and cognitive decline in AD (Kam et al., 2013; Lourenco et al., 2013).