Ultrasound could offer noninvasive treatment for Parkinson’s and depression

The prospect of focusing the beams without destroying tissue might someday diagnose or even restore faulty brain circuits

(Lydia Denworth/ Scientific American) — A macaque monkey sat in front of a computer. A yellow square—the target—appeared in the periphery on the left side of the screen. After a few milliseconds of delay, a second target appeared on the right. The question was: Which target would the monkey look at first? So far so routine as neuroscience experiments go, but the next step was unusual. By non-invasively directing bursts of inaudible acoustic energy at a specific visual area of the brain, a team of scientists steered the animal’s responses. If they focused on the left side of the brain, the monkey looked to the right more often. If they focused on the right side, the monkey looked to the left more often.

The results of the experiment, which were presented last week at the annual Society for Neuroscience meeting, marked the first time that focused ultrasound was safely and effectively used in a nonhuman primate to alter brain activity rather than destroy tissue. A second study, in sheep, had similar results.

“The finding paves the way to noninvasive stimulation of specific brain regions in humans,” says Jan Kubanek, a neural engineer at Stanford University School of Medicine and lead author of the macaque study. The technology might ultimately be used to diagnose or treat neurological diseases and disorders like Parkinson’s disease, epilepsy, addiction and depression.

Other scientists are optimistic. “The idea that, with a very carefully designed dose, you could actually deliver [focused ultrasound] and stimulate the brain in the place you want and modulate a circuit rather than damage it, is a really important proof of principle,” said Helen Mayberg, MD, of Emory University School of Medicine, who was not involved with the study.  (…)

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