Researcher interview: Seung-Schik Yoo, PhD, Brigham and Women’s Hospital and Harvard Medical School, Boston, MA, USA
Focused ultrasound researcher, Seung-Schik Yoo, PhD, is driven by a desire to help people with brain disorders. As leader of the Neuromodulation Working Group formed by the FUS Foundation’s Brain Program, he is collaborating with a multinational, multi-disciplinary team consisting of 27 specialists in neuroscience, physics, biomedical engineering and imaging. Their goal is to determine how pulsed, low intensity focused ultrasound can be used to assess region-specific brain functions and to modify and control aberrant brain activities.
The Working Group is now concentrating on advancing this approach as a tool for functional brain mapping and ideal target localization. Looking toward the future, Yoo foresees an even bigger use of FUS-mediated neuromodulation – the treatment of neurological conditions that range from epilepsy to psychiatric disorders, including chronic depression and substance abuse.
Yoo, who works at Brigham and Women’s Hospital and is an Assistant Professor of Radiology at Harvard Medical School, has published preclinical research showing that the delivery of focused ultrasound-mediated neuromodulation to the cerebral cortex altered brain activity in a selective, reversible way. His experiments used FUS neuromodulation to both inhibit and stimulate motor activity in the brain. In the inhibitory mode, FUS suppressed epileptic seizure activity.
“Right now, we’re chasing after a temporary modulation because I think it is little too early to address the long-term efficacy of this approach,” Yoo observes. “Using this new tool to change the brain function, even temporarily, can lead into a long-term, positive change in the brain function. We call this plasticity in the brain.” Neuroplasticity, he explains, is a self-correcting mechanism that enables areas of the brain to restore balance and regain function.
When used to perform functional brain mapping, FUS-mediated modulation will provide clinicians with more precise veriification that they are targeting the right place in the brain before making a permanent lesion. The first application could be in treating essential tremor. “This technique can be used in conjunction with existing focused ultrasound surgery to really confirm that the target – in this case, the specific thalamic nuclei – is the correct one to cure the essential tremor,” Yoo notes.
“Another application we are thinking about is the treatment of epilepsy. There are a lot of people who suffer from intractable epilepsy, and the current solution is to get a lobotomy, which is a very invasive type of surgery,” Yoo says. “We have found that focused ultrasound can suppress epileptic activities without having any drugs or without surgery. We hope, in the long term, this kind of technique will reduce seizures for the patient by taming and stabilizing aberrant brain areas.”
According to Yoo, the ultimate and largest application for FUS-mediated neuromodulation lies in the field of psychiatry. “Think about the number of people out there who suffer from drug misuse and from depression. We know where it’s coming from; it’s coming from aberrant brain activity patterns. This technology might be able to bring those people who are suffering from psychiatric disorders back to their normal life.”
Additional research is needed before this technique is developed to its full potential. For now, the Neuromodulation Working Group is focusing on advancing FUS-mediated functional brain mapping into human clinical trials. Toward this end, the group has created a research and development roadmap that identifies the final preclinical steps, which include determining neuromodulation parameters and demonstrating the safety of the technique.
“We are in dire need to move this technique to human clinical trials, even preclinical trials,” Yoo says. “We don’t believe technical issues are that much of a hurdle. I think we need more data that that has to be accumulated right before preclinical trials, and it requires more funding. The major obstacle is the need for more capital and more people. We definitely require more personnel and resources to bring this project to a successful conclusion.”
Written by Ellen C., McKenna
Click here to read May 2010 newsletter article, Harvard’s Seung-Schik Yoo discusses research in FUS-mediated neuromodulation.
Click here to read Seung-Schik Yoo’s final progress report related to his FUS Foundation Research Award, which he received in 2008 for a project entitled, FUS-mediated Reversible Modulation of Region-specific Brain Function.