FOS and post-traumatic stress disorder: Abnormal apoptotic cell death within the vmPFC has recently been detected in the traditional single prolonged stress (SPS) model of PTSD (Jia et al., 2018; Pati et al., 2018), and SPS model animals also exhibit reductions in vmPFC c-Fos immunoreactivity (Yu et al., 2015; Pati et al., 2018).