Study reveals new clues to help understand brain stimulation

PUBLIC RELEASE DATE:

29-Sep-2014

Contact: Bonnie Prescott bprescot@bidmc.harvard.edu 617-667-7306 Beth Israel Deaconess Medical Center @BIDMChealth

BOSTON Over the past several decades, brain stimulation has become an increasingly important treatment option for a number of psychiatric and neurological conditions.

Divided into two broad approaches, invasive and noninvasive, brain stimulation works by targeting specific sites to adjust brain activity. The most widely known invasive technique, deep brain stimulation (DBS), requires brain surgery to insert an electrode and is approved by the U.S. Food and Drug Administration (FDA) for the treatment of Parkinson's disease and essential tremor. Noninvasive techniques, including transcranial magnetic stimulation (TMS), can be administered from outside the head and are currently approved for the treatment of depression. Brain stimulation can result in dramatic benefit to patients with these disorders, motivating researchers to test whether it can also help patients with other diseases.

But, in many cases, the ideal sites to administer stimulation have remained ambiguous. Exactly where in the brain is the best spot to stimulate to treat a given patient or a given disease?

Now a new study in the Proceedings of the National Academy of Sciences (PNAS) helps answer this question. Led by investigators at Beth Israel Deaconess Medical Center (BIDMC), the findings suggest that brain networks the interconnected pathways that link brain circuits to one another-- can help guide site selection for brain stimulation therapies.

"Although different types of brain stimulation are currently applied in different locations, we found that the targets used to treat the same disease are nodes in the same connected brain network," says first author Michael D. Fox, MD, PhD, an investigator in the Berenson-Allen Center for Noninvasive Brain Stimulation and in the Parkinson's Disease and Movement Disorders Center at BIDMC.

"This may have implications for how we administer brain stimulation to treat disease. If you want to treat Parkinson's disease or tremor with brain stimulation, you can insert an electrode deep in the brain and get a great effect. However, getting this same benefit with noninvasive stimulation is difficult, as you can't directly stimulate the same site deep in the brain from outside the head," explains Fox, an Assistant Professor of Neurology at Harvard Medical School (HMS). "But, by looking at the brain's own network connectivity, we can identify sites on the surface of the brain that connect with this deep site, and stimulate those sites noninvasively."

Brain networks consist of interconnected pathways linking brain circuits or loops, similar to a college campus in which paved sidewalks connect a wide variety of buildings.

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Study reveals new clues to help understand brain stimulation