NR3C1 and post-traumatic stress disorder: During the initial stage after trauma, elevated cortisol triggers the activation of NMDA receptors through NMDA-extracellular signal-regulated kinase (ERK) and mitogen and stress-activated kinase (MSK) (NMDA-ERK-MSK), and the glucocorticoid receptor (GR) pathways resulting in the formation of recurring memories, which is one of the phenotypes of PTSD (Fig. 3) (Reul and Nutt 2008).