Learned
Volitional Control Over Brain fMRI Activation and Pain
Control over brain
activation and pain learned by using real-time
functional MRI.
Proc Natl Acad Sci USA (2005)
Download paper
deCharms, R. C., Maeda, F.,
Glover, G. H., Ludlow, D., Pauly, J. M., Soneji, D.,
Gabrieli, J. D., and Mackey, S. C.
We all consciously and
unconsciously control our brain for every activity we
initiate, every thought we have, and every emotion or
sensation we experience. Until recently, it has been
unclear as to what extent we can learn to control brain
activity—more specifically, the activity of specific
brain regions--and what impact that control would
have on us. Well-defined regions of the brain are
responsible for the perception of pain, and, in our
pilot study, we sought to answer two questions:
- Can people learn to control
a specific region in the brain involved in pain
perception known as the rostral anterior cingulate
cortex (rACC)?
- Does learned control of the
rACC lead to changes in pain in both healthy
subjects and in patients with chronic pain?
Functional magnetic resonance
imaging (fMRI) is a tool that allows researchers to open
windows into the brain and “see” brain activity. Until
recently, fMRI data needed to be analyzed off-line with
the results being unavailable until many hours after the
subject was scanned. Through software developed by
Dr. Christopher deCharms in collaboration with
Stanford University, we are now able to analyze the
imaging data in near real time and show a subject being
scanned their own brain activity on a moment by
moment basis.
Due to the magnitude and
complexity of this study, we put together an
interdisciplinary team of researchers to tackle the two
questions above. This team included:
Dr. Christopher deCharms (principle investigator for
Omneuron, a San Francisco bay area startup),
Dr. Fumiko Maeda (research associate),
Dr. John Gabrieli (formerly professor of the
Stanford Department of Psychology ; he is now at MIT),
Dr. John Pauly (associate professor of electrical
engineering),
Dr. Gary Glover (professor of radiology and
director, radiological sciences laboratory), Deepak
Soneji and David Ludlow (research assistants in Dr.
Mackey’s lab), and
Dr. Sean Mackey (principle investigator who led the
Stanford team).
We initially took 8 healthy
subjects and used the real time fMRI information to help
them learn to control their brain activations.
The initial part of the study
involved exposing healthy subjects to a heat stimulus.
First, outside of the scanner, we heated a small area of
their skin using a computer-controlled Peltier device.
We determined which temperature resulted in their
experiencing a pain score of 7 out of 10 – where 0=no
pain and 10=the worst pain imaginable. We then scanned
their brain, while their skin was heated, to locate the
regions of the brain responsible for their perception of
pain. We found that an area of the brain – the rostral
anterior cingulate cortex (rACC) – was reliably and
strongly activated in these subjects. Resultantly, we
focused on this area. We then placed subjects in the
scanner and, while intermittently heating their skin,
asked them to change their brain activity while watching
a visual representation of this activity. The visuals
used were both a moving line graph as well as a virtual
flame that got brighter or dimmer as their brain
activity increased or decreased, respectively.
Visual images
subjects and patients visualized while changing their
brain activity. PNAS, December 2005
To help jumpstart the process, we
gave them suggestions as to how they could change their
brain activity in the rACC. This included changing the
focus of their attention on the pain, changing emotional
value of the pain, as well as other similar strategies.
Over several sessions, we monitored how well they
learned to control the rACC and also had them rank their
pain perception. We found a significant increase in the
subject’s ability to control brain activation throughout
training.
These results provided a positive
answer to our first question as to whether subjects
could learn to voluntarily control brain activity in a
specific brain region.
As an answer to our second
question, we found a significant increase in the ability
of healthy subjects to control their pain with repeated
training.
This was not a placebo response.
Multiple control groups were run to insure that the rACC
was truly modulating pain and that the immediate visual
information of the rtfMRI information did indeed assist
the subject in modulating their pain. We found that none
of the control groups had an effect from training and no
significant difference in pain. Overall, the healthy
subjects using the real time information demonstrated an
average of 23% enhancement in control over pain
intensity and 38% enhancement in control over pain
unpleasantness as compared with subjects in the control
groups who did not receive the real time fMRI training.
Finally, we enrolled 8 patients
with chronic intractable pain to test our original two
questions. The study was conducted much like the healthy
controls, except the patients used their own
spontaneous/endogenous pain rather than an externally
applied stimulus. In the small group of pain patients,
they too demonstrated an ability to control their brain
activity and subsequently their pain level. Overall, the
pain patients noticed a 64% decrease in pain ratings on
the McGill Pain Questionnaire (a survey form that
measures both the sensory and emotional aspect of pain)
and an average of 44% decrease on a visual analogue
scale.
Taken together, these results
suggest that, using real time fMRI, people can learn to
strengthen the function of a specific region of the
brain and, through that change, the regions associated
with the perception of pain. It is similar to exercising
muscles, but, in this case, the “muscle” is an area in
the brain. We are currently conducting experiments to
determine if other regions of the brain involved in pain
processing can also be controlled.
A Message for Patients
Suffering From Chronic Pain
We recognize that chronic pain
hugely impacts not only patients but their families and
friends as well. Often people seek out the newest
research and treatments in the hopes of reducing their
pain and suffering. While we are excited about the
results of this study, we believe some cautions are in
order in interpreting our results.
First, this was a small pilot
study. Furthermore, while we studied 8 patients with
chronic pain, they only made up a small part of our
overall study design. The majority of the study involved
healthy subjects experiencing an experimentally induced
noxious stimulus (i.e., a non-injuring heat/pain
stimulus). Consequently, although the results were
statistically significant and the magnitude of the
effects were clinically significant, these results must
be replicated on a much larger scale.
Secondly, we did not actively
monitor the duration of effect for the patients with
chronic pain. Therefore, we have not shown that the
results have any long-term effectiveness. We are
currently studying that question.
Consequently, this study should
not be interpreted to suggest that real time fMRI is in
any way to be thought of as a current treatment for
chronic pain. There is much science and work to be done
to demonstrate real clinical benefit. Although
optimistic about the future, the authors advise that
patients not get their hopes up that this method would
cure their chronic pain. Our results do not give any
indication to support that.
We are currently enrolling
subjects in a long term clinical trial and are looking
for qualified candidates. To determine if you are an
appropriate candidate and for detailed information about
the study, please
click here. If you
are interested, please contact one of our research and
development associates at 650 585-5301.
Control over brain
activation and pain learned by using real-time
functional MRI.
Proc Natl Acad Sci USA (2005)
Link
deCharms, R. C., Maeda, F.,
Glover, G. H., Ludlow, D., Pauly, J. M., Soneji, D.,
Gabrieli, J. D., and Mackey, S. C. |
