Here is a copy of the paper from Ruth Lanius et al that reports on the hyper functional connectivity between the periaqueductal gray, (PAG), the superior colliculus and the amygdala. The take home from this paper is that these reptilian structures at the juncture of the brain stem and the midbrain are the primary threat detectors and they in turn trigger the amygdala. This pattern of hyper connectivity was present in 100% of  those screened in for developmental trauma. For 80% of them, one session of neurofeedback changed the pattern of connectivity showing new connections beginning between the pre-frontal cortex and the amygdala.