All in Your Head
When I told my father about my trip to Omneuron, he asked a question that deCharms is asked often. If you can mentally control pain, why do you need MRI feedback? Shouldn’t the pain, or lack of it, be feedback enough?
The short answer is no. “No other technique that involves feedback has been able to do this sort of thing that well,” says Peter A. Bandettini, director of the fMRI core facility at the National Institutes of Health in Bethesda, MD. According to Bandettini, figuring out why the fMRI feedback is effective is one of the big remaining tasks. He says the answer lies partly in the way fMRI pinpoints precise areas of the brain. But that still leaves a huge question: how do patients actually manipulate the activity in those areas? How do they will control over activity levels? “People figure out how to change the activation, but they don’t know exactly what they do,” he says. “I think if we learn more about that, the technique will become more widely applicable.”
Mackey hopes to eventually unravel the neural systems responsible for the painkilling effects. It’s possible that activating the cingulate leads to the release of chemicals such as endorphins, natural painkillers produced by the brain. In fact, the process may be similar to the one that causes the placebo effect. Placebo treatments can have a profound effect on pain and on certain diseases, notably depression – even inducing changes in the brain. Recent studies show that sham painkillers can trigger the release of endorphins and activate the anterior cingulate, the same brain area under scrutiny in the feedback study. According to deCharms, fMRI feedback may provide a way to consciously control this process.
Even if they are uncertain about the mechanisms behind fMRI feedback, biomedical researchers are excited about exploring its possibilities. “The results from deCharms’s experiment are compelling enough that people will probably be jumping in,” says Bandettini. Adds Tor Wager, a psychologist at Columbia University, “The field of neurofeedback is wide open. … We need more research that explores what people can do themselves.” The possibilities are likely to grow as neuroscientists zero in on the brain areas responsible for different functions and the specific abnormalities linked to different disorders.
Many experts caution, though, that it’s still too early to determine the broad therapeutic potential. “We’re going to have to do the studies and see if feedback is helpful,” says John Gabrieli, an MIT neuroscientist who collaborated with deCharms and is now planning to test fMRI feedback for ADHD. “We need to figure out which disorders are amenable, how long the effects last, and what contexts are needed to support them.” And as in any test of a novel technology, the findings must be repeated in other labs.
It’s possible that some parts of the brain are more susceptible to conscious control than others, and such differences could limit the number of areas that are responsive to fMRI feedback. The anterior cingulate cortex, for example, may be easier to control because it is involved in attention, which we actively modulate throughout the day, as we work or daydream, read or watch television. Diseases such as depression or social phobias, which can often be treated effectively with behavioral therapy, might also be good candidates for fMRI feedback, says Gabrieli.
Yoo, meanwhile, hopes to show that fMRI feedback could speed rehabilitation from stroke or other brain injuries. Patients often lose a particular function, such as speech or part of their vision, when such an injury kills a cluster of neurons. Sometimes the brain can heal itself, either spontaneously or through practice, by reorganizing nearby neurons to take over. This process generally takes place unconsciously, but Yoo says fMRI feedback could teach patients how to consciously activate the regenerating areas.
Among the most compelling therapeutic possibilities is a combination of fMRI feedback with cognitive behavioral therapy, a popular form of talk therapy in which patients learn to change negative thought patterns. During a standard session, a patient might tell the therapist about an event that provokes anxiety and then use specific mental exercises to calm down. In the version deCharms and colleagues are testing, a patient lies in the scanner and communicates with a therapist in the next room through a speaker. Both therapist and patient can watch the patient’s brain activity throughout the session. Using that information, patients might try to consciously alter the activity patterns that flare up when they become anxious.