Using brain imaging to track the effects of treatment of post-traumatic stress disorder
(PTSD), scientists have identified a brain circuit on which a
frequently used and effective psychotherapy (prolonged exposure) acts to
quell symptoms. The findings help explain why the neural circuit
identified is a promising target for additional treatment development,
including brain stimulation therapies.
In an accompanying paper, the authors also report that
they have identified hallmarks in brain activity of people with PTSD
that predict who will benefit from treatment. Both papers appear online
July 18 in the American Journal of Psychiatry.
In prolonged exposure treatment for patients with PTSD,
trained therapists use deliberate and careful exposure to images,
situations, or cues that evoke traumatic memories. The object of the
therapy is to reduce fearful associations with these trauma cues and
replace them with a sense of safety and control over emotional
reactions. The treatment can be very effective, but it has not been
clear how it changes brain processes to have a beneficial effect on
symptoms.
Amit Etkin, M.D., Ph.D., at Stanford University School of
Medicine, led a team of scientists collaborating on this work. The study
enrolled 66 individuals with PTSD; all underwent functional magnetic
resonance brain imaging (fMRI) at rest and while carrying out tasks that
engage different aspects of emotional response and regulation. By
tracking blood flow, fMRI reveals areas of the brain that are active.
Scientists monitor regional brain activity while a subject is carrying
out a given task. Participants were then randomly assigned either to
treatment with exposure therapy or a waitlist. All then had fMRI scans
either following treatment or, if assigned to waitlist, after a
comparable waiting period.
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