Scientists inserted a window in a man's skull to read his brain with ultrasound

In a first, scientists have used ultrasound waves to peer inside a person's brain. The man's brain activity was recorded as he completed tasks outside a medical facility, including playing a video Game. 

To achieve this feat, researchers implanted a material into the man's skull that allowed ultrasound waves to pass into his brain. 

After entering through this "acoustically transparent" window, these waves bounced off boundaries between tissues. Some of the bouncing waves then returned to the ultrasound probe, which was connected to a scanner. The data allowed scientists to build a picture of what was going on in the man's brain, similar to how ultrasound scans can visualize a fetus in the womb. 

The team monitored changes in blood volume in the brain over time, specifically zooming in on brain regions called the posterior parietal cortex and the motor cortex. Both of these regions help to coordinate movement.

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Assessing changes in blood volume is one way to indirectly track the activity of brain cells. That's because when neurons are more active, they require more oxygen and nutrients, which are delivered by blood vessels.

The new study built upon prior research in nonhuman primates. Now working with a person, scientists were able to use ultrasound imaging to monitor the precise neural activity unfolding in a man's brain as he conducted various tasks, such as playing a simple connect-the-dots video Game and strumming a guitar. The team described their findings in a paper published May 29 in the journal Science Translational Medicine.