Posttraumatic stress disorder (PTSD) is a trouble that arises in the aftermath of a traumatic event. The overwhelming resulting stressful memory can be desensitized by a brief therapy, Eye Movement Desensitization and Reprocessing (EMDR). The aim of the present study is to explore the functional brain correlate of such an effective treatment (EMDR) in PTSD.

Sixteen PTSD patients underwent fMRI during negative emotional face recognition task, before and after EMDR treatment. Brain activity changes at test and retest (P<0.005) were compared to those of 16 healthy controls matched for age, gender, and education.

In PTSD patients, EMDR therapy elicited significant functional decreases in deep gray matter (including the amygdala, thalamus, and caudate nucleus) and cortical activities (including notably the precuneus, and the ventromedial and dorsolateral prefrontal cortex), as compared to healthy controls (P<0.005). The right thalamic activity decrease was positively correlated with PTSD symptom reduction as assessed by PCL-S (r=0.62, n=16, P<0.01).

The healing process of traumatic memory desensitization by EMDR would act through a functional decrease in brain regions shown to be disrupted in PTSD. Given the role of these structures in memory, self-perception, fear extinction, REM sleep, reward, and attention, we discuss possible explanations of EMDR mechanisms of action in PTSD that may help further improve this therapy.