Reporter Tang Yitao
Marx & Middot; a well -known identity of Max Hodak is the co -founder and president of NeuralIink, a brain interface company, but now his new identity is the investor of Synchron, another brain interface company. After leaving Neuralink, he became a competitor of Neuralink.
On July 6, Synchron performed the first human brain interface surgery in the United States. The recipient is a patient with muscle atrophy side sclerosis and has lost his ability to move and speak.
Muscle atrophic side cable sclerosis is commonly known as gradient disease. The patient's muscle will gradually shrink, and finally lose the ability to move. Unlike Azheimer's disease, this disease does not affect the patient's neural activity. Even patients can always maintain a sober consciousness.
The purpose of Synchron is to enable these patients to control electronic devices through consciousness, such as sending text messages or online shopping. This is not the first time that Synchron has performed human brain machine interface surgery. Earlier, Synchron had been implanted in four patients in Australia.
The core working principle of the brain interface is to convert the biological electrical signal of the brain into an command that can be recognized by an external control device. Generally speaking, the brain interface is divided into two types: invasive and non -invasive.
Non -invasive brain -type interface is to put the electrode on the skull, which is a primary brain interface. The advantage is that it does not require surgery and will not infringe the human body. But because of this, the signal quality collected is very low.
The invasive brain machine interface needs to directly contact the cerebral cortex through surgery. The advantage of this is that the tested signal noise is low and the loss is small, but craniotomy is required. Neuralink's brain -machine interface, the diameter of the implantation of the wound is greater than 2 cm.
Neuralink electrode implantation schematic diagram ｜ Picture source: TechCrunch
Synchron's uniqueness is that they innovate the electrode implantation method, thereby avoiding craniotomy surgery. During the operation, the doctor will first open a micro -wound on the patient's neck. Through the cervical vein catheter, the mesh implant is input into the blood vessels of the cerebral cortex.
When the catheter is removed, the mesh implant is opened and fused with the outer edge of the blood vessels. According to Shahram & Middot; Shahram Majidi, this process, this process is very similar to implantation of coronary arteries, only a few minutes.
Synchron's mesh electrode ｜ Picture source: synchron
The second step of surgery is to connect the electrode to the computing device of the patient's chest cavity. When neurons work in the brain, the electrode will read these signals. The computing device enlarge these signals and send them to a computer or smartphone through Bluetooth.
Because surgery is minimally invasive, compared to craniotomy surgery, the damage to the human body is very small. Although Synchron did not announce the postoperative recovery of the patient, the main doctor Magidi said: "The implantation surgery is very smooth, and the patient can go home 48 hours after surgery."
But Synchron's technical route is not perfect. Since the implant exists in the cerebral blood vessels and does not directly contact the neurons, the receiving signal will be attenuated. In addition, the number of electrodes is also limited. Because the electrodes can only be placed on the bracket, the current synchron can only achieve 16 channels. In contrast, Neuralink has achieved 1024 channels.
Another problem facing the invasive interface is biological compatibility. Due to the role of the immune system, it is used for a long time, and a layer of nerve glue cells will be slowly wrapped around the implant, making the collected nerve signal weakened. This also means that over time, patients need to re -undergo surgery to replace the implant. At present, the longest working time of brain implants in the human body is two years.
In general, people are eager to achieve the scenes in science fiction novels, but security is the worry of everyone. The incoming interface is on one end of the heaven, and the non -dumped interface is on the other end of the heaven. All brain -machine interface companies do are found in these two sections -how to achieve higher ceiling as much as possible under the premise of security.
No technical route is perfect. Synchron is preferentially considered to be safe, and Neuralink is more radical. But for now, Synchron has still led its competitors -Neuralink is also stuck in FDA's human experiment approval.