Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Ultrasound directed to the human brain can boost sensory performance

13.01.2014
Virginia Tech Carilion Research Institute scientists say ultrasound ranks with leading neuromodulation techniques in achieving spatial resolution

Whales, bats, and even praying mantises use ultrasound as a sensory guidance system — and now a new study has found that ultrasound can modulate brain activity to heighten sensory perception in humans.

Virginia Tech Carilion Research Institute scientists have demonstrated that ultrasound directed to a specific region of the brain can boost performance in sensory discrimination. The study, published online Jan. 12 in Nature Neuroscience, provides the first demonstration that low-intensity, transcranial-focused ultrasound can modulate human brain activity to enhance perception.

"Ultrasound has great potential for bringing unprecedented resolution to the growing trend of mapping the human brain's connectivity," said William "Jamie" Tyler, an assistant professor at the Virginia Tech Carilion Research Institute, who led the study. "So we decided to look at the effects of ultrasound on the region of the brain responsible for processing tactile sensory inputs."

The scientists delivered focused ultrasound to an area of the cerebral cortex that processes sensory information received from the hand. To stimulate the median nerve — a major nerve that runs down the arm and the only one that passes through the carpal tunnel — they placed a small electrode on the wrist of human volunteers and recorded their brain responses using electroencephalography, or EEG. Then, just before stimulating the nerve, they began delivering ultrasound to the targeted brain region.

The scientists found that the ultrasound both decreased the EEG signal and weakened the brain waves responsible for encoding tactile stimulation.

The scientists then administered two classic neurological tests: the two-point discrimination test, which measures a subject's ability to distinguish whether two nearby objects touching the skin are truly two distinct points, rather than one; and the frequency discrimination task, a test that measures sensitivity to the frequency of a chain of air puffs.

What the scientists found was unexpected.

The subjects receiving ultrasound showed significant improvements in their ability to distinguish pins at closer distances and to discriminate small frequency differences between successive air puffs.

"Our observations surprised us," said Tyler. "Even though the brain waves associated with the tactile stimulation had weakened, people actually got better at detecting differences in sensations."

Why would suppression of brain responses to sensory stimulation heighten perception? Tyler speculates that the ultrasound affected an important neurological balance.

"It seems paradoxical, but we suspect that the particular ultrasound waveform we used in the study alters the balance of synaptic inhibition and excitation between neighboring neurons within the cerebral cortex," Tyler said. "We believe focused ultrasound changed the balance of ongoing excitation and inhibition processing sensory stimuli in the brain region targeted and that this shift prevented the spatial spread of excitation in response to stimuli resulting in a functional improvement in perception."

To understand how well they could pinpoint the effect, the research team moved the acoustic beam one centimeter in either direction of the original site of brain stimulation – and the effect disappeared.

"That means we can use ultrasound to target an area of the brain as small as the size of an M&M," Tyler said. "This finding represents a new way of noninvasively modulating human brain activity with a better spatial resolution than anything currently available."

Based on the findings of the current study and an earlier one, the researchers concluded that ultrasound has a greater spatial resolution than two other leading noninvasive brain stimulation technologies — transcranial magnetic stimulation, which uses magnets to activate the brain, and transcranial direct current stimulation, which uses weak electrical currents delivered directly to the brain through electrodes placed on the head.

"Gaining a better understanding of how pulsed ultrasound affects the balance of synaptic inhibition and excitation in targeted brain regions — as well as how it influences the activity of local circuits versus long-range connections — will help us make more precise maps of the richly interconnected synaptic circuits in the human brain," said Wynn Legon, the study's first author and a postdoctoral scholar at the Virginia Tech Carilion Research Institute. "We hope to continue to extend the capabilities of ultrasound for noninvasively tweaking brain circuits to help us understand how the human brain works."

"The work by Jamie Tyler and his colleagues is at the forefront of the coming tsunami of developing new safe yet effective noninvasive ways to modulate the flow of information in cellular circuits within the living human brain," said Michael Friedlander, executive director of the Virginia Tech Carilion Research Institute and a neuroscientist who specializes in brain plasticity. "This approach is providing the technology and proof of principle for precise activation of neural circuits for a range of important uses, including potential treatments for neurodegenerative disorders, psychiatric diseases, and behavioral disorders. Moreover, it arms the neuroscientific community with a powerful new tool to explore the function of the healthy human brain, helping us understand cognition, decision-making, and thought. This is just the type of breakthrough called for in President Obama's BRAIN Initiative to enable dramatic new approaches for exploring the functional circuitry of the living human brain and for treating Alzheimer's disease and other disorders."

A team of Virginia Tech Carilion Research Institute scientists — including Tomokazu Sato, Alexander Opitz, Aaron Barbour, and Amanda Williams, along with Virginia Tech graduate student Jerel Mueller of Raleigh, N.C. — joined Tyler and Legon in conducting the research.

In addition to his position at the institute, Tyler is an assistant professor of biomedical engineering and sciences at the Virginia Tech-Wake Forest University School of Biomedical Engineering and Sciences. In 2012, he shared a Technological Innovation Award from the McKnight Endowment for Neuroscience to work on developing ultrasound as a noninvasive tool for modulating brain activity.

"In neuroscience, it's easy to disrupt things," said Tyler. "We can distract you, make you feel numb, trick you with optical illusions. It's easy to make things worse, but it's hard to make them better. These findings make us believe we're on the right path."

Paula Byron | EurekAlert!
Further information:
http://www.vt.edu

More articles from Health and Medicine:

nachricht Real-time imaging of lung lesions during surgery helps localize tumors and improve precision
30.07.2015 | American Association for Thoracic Surgery

nachricht Experimental MERS vaccine shows promise in animal studies
29.07.2015 | NIH/National Institute of Allergy and Infectious Diseases

All articles from Health and Medicine >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: On the crest of the wave: Electronics on a time scale shorter than a cycle of light

Physicists from Regensburg and Marburg, Germany have succeeded in taking a slow-motion movie of speeding electrons in a solid driven by a strong light wave. In the process, they have unraveled a novel quantum phenomenon, which will be reported in the forthcoming edition of Nature.

The advent of ever faster electronics featuring clock rates up to the multiple-gigahertz range has revolutionized our day-to-day life. Researchers and...

Im Focus: Superfast fluorescence sets new speed record

Plasmonic device has speed and efficiency to serve optical computers

Researchers have developed an ultrafast light-emitting device that can flip on and off 90 billion times a second and could form the basis of optical computing.

Im Focus: Unlocking the rice immune system

Joint BioEnergy Institute study identifies bacterial protein that is key to protecting rice against bacterial blight

A bacterial signal that when recognized by rice plants enables the plants to resist a devastating blight disease has been identified by a multi-national team...

Im Focus: Smarter window materials can control light and energy

Researchers in the Cockrell School of Engineering at The University of Texas at Austin are one step closer to delivering smart windows with a new level of energy efficiency, engineering materials that allow windows to reveal light without transferring heat and, conversely, to block light while allowing heat transmission, as described in two new research papers.

By allowing indoor occupants to more precisely control the energy and sunlight passing through a window, the new materials could significantly reduce costs for...

Im Focus: Simulations lead to design of near-frictionless material

Argonne scientists used Mira to identify and improve a new mechanism for eliminating friction, which fed into the development of a hybrid material that exhibited superlubricity at the macroscale for the first time. Argonne Leadership Computing Facility (ALCF) researchers helped enable the groundbreaking simulations by overcoming a performance bottleneck that doubled the speed of the team's code.

While reviewing the simulation results of a promising new lubricant material, Argonne researcher Sanket Deshmukh stumbled upon a phenomenon that had never been...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

3rd Euro Bio-inspired - International Conference and Exhibition on Bio-inspired Materials

23.07.2015 | Event News

Clash of Realities – International Conference on the Art, Technology and Theory of Digital Games

10.07.2015 | Event News

World Conference on Regenerative Medicine in Leipzig: Last chance to submit abstracts until 2 July

25.06.2015 | Event News

 
Latest News

Surprising similarity in fly and mouse motion vision

30.07.2015 | Life Sciences

Efficient Infrared Heat Saves Time and Energy in the Manufacture of Motor Vehicle Carpets

30.07.2015 | Trade Fair News

Roentgen prize goes to Dr Eleftherios Goulielmakis

30.07.2015 | Awards Funding

VideoLinks
B2B-VideoLinks
More VideoLinks >>>