For the first time, scientists have made use of ultrasound waves to look into the brain of a person.
The brain activity of the man involved was recorded as he performed tasks, such as playing a video game, outside a medical institution.
Brain Wave Ultrasound
In order to achieve such a feat, the scientists implanted a material into the man's skull. This material enabled the passing of ultrasound waves into his brain. After the waves went into the window that was "acoustically transparent," they bounded off boundaries across tissues.
Some of these bouncing waves went back to the ultrasound probe, which was linked to a scanner. Such data enabled the scientists to come up with a picture of what happened in the man's brain. This was similar to how scans of ultrasounds could visualize a fetus inside a womb.
The team looked into brain blood volume changes over time. They specifically zoomed into regions of the brain known as the motor cortex and the posterior parietal cortex, which are both involved with movement coordination.
Assessing blood volume changes is just one way to indirectly monitor brain cell activity. This is due to how when neurons have higher activity, they would require more nutrients and oxygen, which the blood vessels deliver.
The novel study built on earlier research on nonhuman primates. Now, as they worked with a person, the scientists made use of ultrasound imaging in order to examine the exact neural activity that unfolded in the brain of the man as he went on with different tasks.
Findings were described in the "Functional ultrasound imaging of human brain activity through an acoustically transparent cranial window" study.
Dr. Charles Liu, a co-senior author of the study and neurosurgeon from the University of California, explained that similar to what was observed among nonhuman primates, the ultrasound data of the patient showed intentions as actions were taken.
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Functional Ultrasound Imaging For Brain Activity Monitoring
Functional ultrasound imaging, which means that ultrasound monitors blood volume and brain changes, is thought to be a promising alternative to usual brain imaging techniques, such as fMRI (functional magnetic resonance imaging). This is because of how it is thought to have a higher sensitivity to changes in brain activity.
Moreover, the images that result also have a higher resolution. The method does not necessitate patients to be still in a machine for prolonged periods.
One may also theoretically monitor brain activity in actual real-life settings. While this is possible with ambulatory EEG, it monitors electrical activity over blood flow. It also does so through the head and skull's skin, making it lack precision.
In a similar way, the human skull has been a historical ultrasound wave barrier that prevents these waves from going into the brain. However, in the new study, the researchers were able to overcome this issue by testing the method in a patient with a skull area removed. He underwent the portion removal in order to relieve some brain pressure after he experienced a severe TBI (traumatic brain injury).
For the majority of cases, patients of TBI who go through such a procedure are typically given a custom-built implant or a titanium mesh. This implant or mesh may serve as a replacement for the missing skull portion. For this case, the team created an acoustically transparent window implant.
The study authors think that, in the future, the novel technique may not just work for TBI patients.
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