On January 29, local time, Musk posted on his social platform: "Yesterday, the first human patient underwent Neuralink implantation surgery and is currently recovering well. Preliminary results show that the SPIKE signal was acquired. ”
As the most valuable invasive brain-computer interface company at this stage, Neuralink's R&D and clinical trial progress have attracted much attention. On May 25, 2023, Neuralink announced that it has received FDA approval to initiate clinical trials of brain-computer interface devices implanted in humans, and in September, it began recruiting patients with quadriplegia due to ALS. According to media reports, thousands of patients around the world waited in line after the announcement to participate in Neuralink's clinical trial. In just over four months, the initial good news came.
Composition of the Neuralink brain-computer interface implant N1
Coincidentally, on January 30, Beijing time, on the day Musk posted the article, the official website of Tsinghua University released a news that "the first clinical trial of wireless minimally invasive brain-computer interface cooperated by Tsinghua University and Xuanwu Hospital was successfully carried out", and the first patient with spinal cord injury can achieve certain brain control function after three months of home brain-computer interface rehabilitation training, and the sensory evoked potential response has also improved. It is understood that the first patient implantation operation in China will be carried out on October 24, 2023, and the first patient implantation time of Musk Neuralink will be on January 28, 2024, nearly 3 months apart.
So, what does Musk's mention of "good recovery and monitoring of spike signals" mean, and what is the differentiated design of the minimally invasive brain-computer interface route released by Tsinghua University?
What does it mean to "recover well, spike signal"?
Four months later, Musk briefly released the progress of the clinical trial, what does it mean? "Good recovery mainly refers to safety, good recovery from a medical point of view, and of course safety needs long-term monitoring. Dr. Liu Bing, an associate researcher at the Institute of Automation of the Chinese Academy of Sciences, told 36Kr, "In terms of effectiveness, the monitoring of the spike signal has been shown to be very effective to a certain extent, and if the spike signal can be detected in multiple channels, it means that the implantation is very successful." The first insurmountable hurdle, 'how to get data', is halfway through Neuralink. Subsequently, through the analysis, decoding, and encoding of neuronal signals, the data is transformed into external control signals, which also needs to be observed. ”
Dr. Deng Chunshan, co-founder and CEO of Weiling Medical, also expressed a similar view on 36Kr: Neuralink uses microfilament penetration electrodes, and the spike signal is recorded during the operation, indicating that the implantation effect is good. "Good recovery" should mean that the patient is in good condition after waking up from the operation, such as the awake state after anesthesia, the recovery of fever symptoms, the condition of the wound, etc.
The Spike signal (front potential) mentioned by Musk and the two researchers refers to high-frequency pulsed electrical signals released at the level of a single neuron, which can be parsed and encoded.
By analogy, if LFPs (local field potential signals, the type of signal collected by traditional neuromodulation devices) collect the sound emitted by an entire basketball court, the signal is limited and mixed, and the neuronal spike signal is the sound emitted by everyone on the court, and the signal accuracy and data amount collected are much higher than the field potential signal. The simultaneous improvement of the quality and quantity of signal data may lead to the upgrading of the neuromodulation paradigm and the brain science research paradigm.
Musk's announcement of the phased clinical progress of Neuralink has encouraged the confidence of the industry to a certain extent. Of course, as an invasive implant surgery, the long-term safety and effectiveness of the device after implantation still need to be monitored, including whether scar tissue will appear near the flexible electrode in the future, which will affect the signal strength and signal-to-noise ratio, and whether there will be immune rejection due to biocompatibility.
In order to improve the service life of the device after implantation in the human body, Neuralink has led the development trend of "high-throughput flexible electrodes", and has become an important direction for researchers at home and abroad to find new electrode materials and processes that can be in vivo for a long time and accurately record neuronal signals. Of course, in addition to the electrode technology that collects the signal, the high-channel and low-power chips, the algorithm system for decoding the signal, the surgical robot implanted with the electrode, and even the clinical resources and medical capabilities for canine monkey animal experiments and exploratory human trials all determine the application trend of this complex medical device.
New progress in clinical trials of minimally invasive implanted brain-computer interface in China
The field of brain-computer interfaces requires huge resource investment, and China and the United States are the countries most likely to give birth to global influence companies. On January 30, Beijing time, on the day Musk announced the above progress, a news was released on the official website of Tsinghua University, saying that the team of Tsinghua University and Xuanwu Hospital successfully conducted the first clinical trial of wireless minimally invasive brain-computer interface.
Source: Tsinghua University official website
Specifically, the clinical trial will be carried out on October 24, 2023, and the implanted minimally invasive implantable brain-computer interface device will be designed and developed by a team led by Professor Hong Bo of Tsinghua University School of Medicine, and the surgical planning and implantation surgery will be presided over by the team of President Zhao Guoguang and Director Shan Yongzhi of Xuanwu Hospital. The first patient to receive implantation was a complete spinal cord injury to the cervical spine caused by a car accident and has been quadriplegic for 14 years. On January 29, the above-mentioned team held a summary meeting of the clinical trial phase and announced that the first patient had made a breakthrough in the rehabilitation of brain-computer interface.
Unlike Musk's Neuralink's path of implanting flexible electrodes in the cerebral cortex, the brain-computer interface electrodes developed by Professor Hong Bo's team at Tsinghua University are hard electrodes, which are covered outside the dura mater, which is located between the skull and the cerebral cortex to protect nerve tissue.
According to the disclosure, "after three months of home brain-computer interface rehabilitation training, patients can drive pneumatic gloves through EEG activities to achieve brain control functions such as self-drinking water, with a grasping accuracy rate of more than 90%, and the ASIA clinical score and sensory evoked potential response of patients with spinal cord injury have been significantly improved." ”
Previously, Professor Hong Bo said in an interview with 36Kr that understanding minimally invasive implanted brain-computer interface technology can be compared with the two technical routes. One is the non-invasive scalp brain computer interface being made by many research groups in China, which needs to rely on conductive glue to ensure that the electrodes are in contact with the scalp, and cannot continue to work for a long time. The other is invasive brain-computer interfaces such as BrainGate in the United States, which need to implant hundreds of neural electrodes in the cerebral cortex, which is traumatic and difficult to solve the problem of immune inflammation.
The wireless minimally invasive implanted brain-computer interface system is implanted on the human dura mater, does not invade the nerve cells of the cerebral cortex, obtains a high signal-to-noise ratio through the signal enhancement technology combining software and hardware, and effectively solves the problem of biocompatibility.
According to the press release released by Tsinghua University, the implantation of the second brain-computer interface system for a patient with spinal cord injury has been carried out in Tiantan Hospital on December 19, 2023, with normal signal reception and the patient is undergoing home rehabilitation training.