Using MRI to measure brain activity, researchers have shown patients with post-traumatic stress disorder (PTSD) have larger brain responses in the locus coerulus, a region that controls arousal and reactivity.

“Behavioral and autonomic hyperresponsiveness in PTSD may arise from a hyperactive alerting/orienting system in which processes related to attention and motor preparation localized to lateral premotor cortex, intraparietal sulcus, and posterior superior cerebellar cortex are modulated by atypically high phasic noradrenergic influences originating in the locus coeruleus,” wrote first author first author Christoph Naegeli with the University of Zurich in Switzerland and colleagues.

The study, published in Biological Psychiatry, included 54 people (42 women and 12 men) who had been exposed to trauma. Twenty-eight individuals with an average age of 38.5 experienced PTSD, while 26 with an average of 40.35 did not.

Individuals were exposed to random bursts of noise. Those individuals with PTSD were more likely to blink their eyes (10.3 percent to 5.3 of non-PTSD participants). The PTSD individuals also increased heart rate, skin conductance and pupil area responses, which indicated more prominent autonomic responses.

"Our results suggest that targeting locus coeruleus system hyperactivity with new pharmacological or psychotherapeutic interventions are approaches worthy of further investigation," said Mueller-Pfeiffer et al. “The increased LC activity we observed in the PTSD group following presentations of loud noise is consistent with the finding of higher LC activity evoked by stressful paw compression in a PTSD mouse model.”