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People usually associate ultrasounds to pregnancy since these machines are often used to follow the growth of fetuses. The machine allows doctors to detect and identify invisible objects and now, it might also be used to boost people's brain performance. According to a new study, researchers reported that when ultrasounds were placed directly on top of specific brain areas, they improved people's cognitive functions when it came to distinguishing between two sensory inputs.

For this study, the researchers from Virginia Tech Carilion Research Institute concentrated on the cerebral cortex. This region of the brain is responsible for processing sensory input that comes from the hands. In order to stimulate this region, the researchers placed one small electrode on the wrist of their participants. From there, the researchers were able to stimulate the median nerve, which is a nerve that passes through the carpel tunnel and runs along the arm. The researchers measured and recorded brain activity using an EEG (electroencephalography).

The team discovered that when the ultrasound was placed on top of the cerebral cortex region, the machine was able to reduce the EEG signal and lower the brain's activity that was in charge of encoding stimulation that comes from the hands. The researchers then carried out two neurological tests.

The first one, the two-point discrimination test, measured the participants' ability to discriminate between two nearby objects that were touching the skin at different points. The researchers used two pins and touched the participants' skin at two points. As the points got closer to one another, it became harder to distinguish the two pins from one another. The other test, the frequency discrimination task, measured the participants' sensitivity to air puffs. The participants felt a series of air puffs that were being blown at an increasing speed. The faster the puffs came, the harder it would be to separate the puffs from one another.

The researchers found that the ultrasound helped improve the participants' ability to identify the two pins. The participants also exhibited an improved ability to distinguish small frequency differences between the air puffs.

"We can use ultrasound to target an area of the brain as small as the size of an M&M," study researcher William Tyler, a neuroscientist at the Virginia Tech Carilion Research Institute, said. "This finding represents a new way of noninvasively modulating human brain activity with a better spatial resolution than anything currently available."

He added, according to the press release, "Our observations surprised us. Even though the brain waves associated with the tactile stimulation had weakened, people actually got better at detecting differences in sensations."

The researchers explained that the ultrasound could have affected the brain's ability to process excitation and inhibition. However, more research would need to be conducted to understand what ultrasounds could potentially do for the brain. The study was published in Nature Neuroscience.