According to the latest issue of the journal Nature Neuroscience, a new study has confirmed that functional ultrasound (FUS) technology developed by researchers at the California Institute of Technology can become the basis for an "online" brain computer interface (BMI) that can read brain activity and decipher its meaning using a machine learning programmed decoder, thereby controlling a machine with extremely short latency A computer that can accurately predict motion. In 2021, researchers at the California Institute of Technology developed a method of using functional ultrasound to read brain activity, which is a much less invasive technique. The working principle of ultrasound imaging is to emit high-frequency sound pulses, and then measure the echo of these sound vibrations in materials such as various tissues of the human body. Sound waves propagate at different speeds in these types of tissues and reflect at the boundaries between them. Changes in neuronal activity can cause changes in their utilization of metabolic resources such as oxygen. These resources are replenished through blood, which is the key to functional ultrasound. In this study, researchers used ultrasound to measure changes in blood flow to specific brain regions. They can record tiny changes in blood flow in the brain, with a spatial area only 100 micrometers wide, about the width of a hair. They are able to simultaneously measure the activity of tiny nerve cell clusters widely distributed throughout the brain, some of which are as small as 60 neurons. Researchers used functional ultrasound to measure brain activity in the posterior parietal cortex (PPC) of non-human primates, which is responsible for planning and assisting in motor execution. The experimental animals were taught two tasks: moving their hands to guide the cursor on the screen, and moving their eyes to look at specific parts of the screen. They only need to consider performing tasks, rather than actually moving their eyes or hands, as BMI can read their brain activity. The ultrasound data is sent in real-time to the decoder, which then generates a control signal and moves the cursor to the desired location. BMI was able to successfully perform this operation on 8 radial targets with a small average error. 【 Editor in Chief Circle 】 Brain computer interface technology with a strong sci-fi color is entering reality. Elon Musk, the Iron Man of Silicon Valley, has invested in brain computer interface technology, further making it a hot topic and gaining social attention. However, from the current perspective, this technology is still in its early stages and has many shortcomings. For example, invasive brain computer interfaces often cause damage to the user's body, and may even lead to inflammatory reactions at the wound site; The non-invasive brain computer interface requires wearing a bulky helmet, and the experience needs to be improved. The scientific research progress in fields such as neuroscience, electronic information technology, and materials science related to brain computer interfaces will continuously promote the iteration and upgrading of this technology. (Lai Xin She)