Ultrasound waves sent to specific brain regions can alter a person's mood, according to a new study published in the journal Brain Stimulation. The research, conducted by University of Arizona researchers, has led to further investigations with the hope that this procedure could one day be used to treat mental disorders such as depression and anxiety.
Dr. Stuart Hameroff, director of the UA's Center for Consciousness Studies, became interested in applying ultrasound to the human brain when he read about a study by Jamie Tyler, Ph.D., at the Virginia Polytechnic Institute. Tyler found physiological and behavioral effects in animals when ultrasound waves were applied through the skull.
Hameroff knew that ultrasound vibrates in megahertz frequencies at about 10 million vibrations per second, and that microtubules, protein structures inside brain neurons linked to mood and consciousness, also resonate in megahertz frequencies. Hameroff wanted to try ultrasound treatment for mood in human brains.
"I said to my anesthesiology colleagues, 'we should try this on chronic pain patient volunteers'," he said.
His colleagues respectfully suggested he try it on himself first. Hameroff agreed.
He placed an ultrasound transducer against his head for 15 seconds and felt no effect.
"I put it down and said, 'well, that's not going to work.' And then about a minute later I started to feel like I'd had a martini," he said.
His mood was elevated for the next hour or two, Hameroff said.
To be sure that his happier mood was not just a placebo effect — an imagined effect created from his expectation to feel a change — Hameroff set out to properly test the treatment with a clinical trial.
After obtaining approval by the research committee and the hospital, as well as patient-informed consent, Hameroff and his colleagues applied transcranial ultrasound to 31 chronic pain patients at The University of Arizona Medical Center, South Campus, in a double blind study in which neither doctor nor subject knew if the ultrasound machine had been switched on or off.
When the machine was on, patients reported improvements in mood for up to 40 minutes following treatment with brain ultrasound, compared with no difference in mood when the machine was switched off.
The findings may lead to a wide range of new applications in ultrasound treatment.