Varying changes in local blood flow in two areas of the brains of
auto-crash survivors predicted later adaptation to their traumatic experience,
according to a study "of recovery rather than pathology" in the
August 15 Biological Psychiatry.
The study scanned the brains of survivors within a few weeks of their
accidents and before a diagnosis of posttraumatic stress disorder is possible.
Positron emission tomography (PET) scans showed less blood flowing to the
amygdala and more to the medial prefrontal cortex (mPFC) of subjects when
listening to recountings of their trauma than when listening to neutral
"There are specific brain correlates of normal, healthy recovery of
exposed individuals, and those brain activities are located in the mPFC and
the amygdala," said lead author Elizabeth Osuch, M.D., now an associate
professor of psychiatry at the University of Western Ontario in London,
Ontario, in an interview. The research was conducted when Osuch was at the
Center for the Study of Traumatic Stress at the Uniformed Services University
of the Health Sciences in Bethesda, Md.
"In people with long-term PTSD, we find hyperactive amygdala and
hypoactive mPFC—the opposite of what we're finding in these
The research is another step in understanding the biological basis of
trauma and recovery, said Osuch. The work was funded by the National Institute
of Mental Health, and the authors said it is the first study addressing
neurophysiological responses to traumatic reminders observed before a
diagnosis of PTSD is possible.
The researchers used PET scans to measure regional blood flow in the brains
of 22 survivors of motor-vehicle collisions (MVC) and 12 nontraumatized
control subjects. None had a history of head injury or major medical illness,
but the accident victims had significantly higher Beck Depression Inventory
scores than controls.
Osuch's group had hoped to look at both resilience and recovery and at
psychopathology. However, people with more severe PTSD and more severe
avoidance symptoms did not volunteer to take part in the study, she said.
After recruitment but before scanning, the survivors described their
accidents in a "traumatic-reminder narrative." One of these was
then selected as a standardized trauma narrative, played for the controls.
Survivors also provided a neutral narrative of a favorite activity not related
to the accident.
Subjects were scanned within an average of 20 days following their
accidents. Narratives were recorded and played back to the subjects during the
scan. Survivors were evaluated (but not scanned) three months later as
The session began with one resting scan, followed by pairs of the neutral
and trauma scans, in that order.
At rest, compared with healthy controls, the accident victims showed higher
resting blood flow in a right medial prefrontal cortex (mPFC) area in the
anterior cingulate sulcal area and lower flow in the right amygdala. During
subsequent scans, accident victims listening to trauma narratives showed
decreased flow in the right amygdala and left amygdala/perirhinal cortex,
compared with when they heard the neutral narratives.
Subjects were evaluated using the Impact of Events Scale-Revised (IES-R).
On average, the accident survivors' IES-R score was above the threshold
for clinical significance. However, at the three-month follow-up evaluation,
only four of the 22 subjects had elevated IES-R scores. Only one met criteria
"Thus, most of the MVC subjects were 'resilient'—that is, they
experienced a traumatic event, showed a transient stress response, and went on
to recovery," wrote the authors. "[The results] suggest an
adaptive process in recovering individuals that involves deactivation of the
perirhinal cortex, perhaps as a means of terminating or preventing
The clinical value of this information is still unclear, but the research
may contribute to broader discussions of psychological injury and health, said
"We live in a world where mental illness is very much
stigmatized," she said. "We stigmatize pathology but don't
understand the biological basis of the pathology. Neither do we understand or
appreciate the biological aspects of resilience or health. This is one more
thing to add to that understanding."
An abstract of "Neurophysiological Responses to Traumatic
Reminders in the Acute Aftermath of Serious Motor Vehicle Collisions Using
[15O]-H2O Positron Emission Tomography" can be