Neuroimaging provides an opportunity to understand core processes that mediate the experience of emotions in healthy individuals as well as dysregulation of these processes in conditions such as posttraumatic stress disorder (PTSD). The first decade of neuroimaging research produced symptom provocation, cognitive activation, and functional connectivity studies that highlighted the role of the medial prefrontal cortex (mPFC), amygdala, sublenticular extended amygdala (SLEA), and hippocampus, in mediating symptom formation in PTSD. There is a growing realization that a number of other psychological processes are relevant to PTSD, and they are emerging as a new focus of neuroimaging research. These include fear conditioning, habituation, and extinction; cognitive-emotional interactions; and self-related and social emotional processing. Neuroimaging findings are reviewed that suggest that the mPFC is implicated in a number of these processes. It is proposed that the mPFC plays a role in the "contextualization" of stimuli, and dysregulation of contextualization processes might play a key role in the generation of PTSD symptoms.