There is a range of immediate orienting and defense responses available when a threat is perceived, and a separate but overlapping system of vigilance when there is awareness of a potential threat. Vogt, Aston-Jones, and Vogt propose that the reduced anterior cingulate functioning repeatedly demonstrated in posttraumatic stress disorder (PTSD) during emotional tasks facilitates the firing of locus coeruleus (LC) neurons to create a state of hyperarousal. The noncognitive suppression of emotions in young trauma sufferers is based in the areas of the ventral prefrontal cortex (PFC), which has outputs to the defense response and threat evaluation regions of the amygdala, the periaqueductal gray (PAG), and the nucleus accumbens, among others. Deep brain stimulation can be used clinically without activation of a fearful freeze response, so ventral areas of the PAG are also involved in physiological states of relaxation, comfort, and soothing from pain.