New progress in the technology of using thoughts to make cockroaches obedient! The performance of "Avatar"-style brain-brain interface is improved by 2-3 orders of magnitude
Latest update time：2020-03-25
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The rate of information transmission is very low, which is the main bottleneck restricting the development of brain-brain interfaces.
Text | Fu Jing
The "brain-brain interface" technology (BtBIs) that can achieve xenobiotic control is becoming more and more mature.
On March 20, 2020, Luo Minmin's laboratory at the Beijing Institute of Life Sciences/Institute of Biomedical Sciences, Tsinghua University published a paper titled "An optical brain-to-brain interface supports rapid information transmission for precise locomotion control" in SCIENCE CHINA Life Sciences, an internationally renowned journal with the highest academic level in China's life sciences.
In this paper, the research team introduced how the authors constructed an optical brain-brain interface using fiber optic recording and optogenetic activation technology, and achieved motion information transmission at a high information transfer rate between two mice, thereby verifying in principle the possibility of brain-brain interfaces to precisely control animal movements across individuals.
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Optical brain-to-brain interface supports precise motion control
Fast information transmission
The concept of brain-brain interface may be familiar to those who have watched the sci-fi movie "Avatar". In the movie, people on Earth can remotely control the genetically modified blue humanoid Na'vi on Pandora through direct brain-to-brain information transmission.
Generally speaking, communication between people and other animals relies on vision, hearing, smell or touch, but in fact, brain-brain interfaces can also realize direct information transmission between biological brains. However, due to current technical limitations,
the rate of information transmission is very low, which is also a major bottleneck restricting the development of brain-brain interface technology.
In addition, Luo Minmin's laboratory recently discovered that a type of neurons expressing neuromedin B (NMB) in the nucleus incerta (NI) of the brainstem can control movement speed, wakefulness, and hippocampal theta waves related to spatial memory. The related paper was published in the journal Nature Communications on January 14, 2020.
In simple terms, the activity of neurons expressing NMB in the NI can accurately predict and control movement speed. As shown in the figure below, the activity of neurons expressing NMB in the NI is positively correlated with the animal's movement speed, arousal level, and hippocampal theta waves.
This time, based on the above research results, the research team designed an optical brain-brain interface to transmit information about movement speed between two mice (the "Master" control mouse and the "Avatar" mouse), achieving precise and real-time control of cross-animal movement at a high information transmission rate.
The specific process is as follows:
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Movement speed parameters were extracted from NMB-expressing neurons in the NI of Avatar mice;
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The Ca2+ (calcium ion) signals from the NI of control mice were recorded optically in real time using a model trained with a support vector machine (SVM, a type of generalized linear classifier that performs binary classification on data);
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Translating this into patterned optogenetic stimulation of the NI of the Avatar mouse successfully guided the Avatar mouse to closely mimic the movements of the control mouse.
It is worth mentioning that
the information transmission rate of this process reached 4.1 bits/s, which is 2-3 orders of magnitude higher than the information transmission rate of brain-brain interface based on electrophysiology
.
[Control the rate of information transmission between the mouse and the Avatar mouse]
In addition, the research team also emphasized the importance of choosing appropriate neural circuits and recording and stimulation tools when improving the information transfer rate of brain-brain interfaces. The research team believes that the experiment ultimately achieved a high information transfer rate because, on the one hand, the researchers used neurons expressing NMB in NI to extract movement speed parameters; on the other hand, the researchers chose to use a fiber optic recording system to record its changes.
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About Brain-Brain Interfaces
In recent years, we have all heard about some progress in brain-computer interfaces. In 2017, Elon Musk, CEO of Tesla, CEO and CTO of SpaceX, and Chairman of the Board of Directors of Solar City, established Neuralink, a brain-computer interface company. In this field, research teams from various countries have also frequently refreshed our cognition - on January 16, 2020, Zhejiang University announced that the first clinical study of implantable brain-computer interfaces in China was successful.
In comparison, brain-brain interfaces can be said to be still relatively far away from the general public.
Leifeng.com learned that the brain-to-brain interface consists of two parts - a decoder that retrieves useful information from the neural activity of the source brain, and an encoder that converts the source information into appropriate changes in neuronal activity in the target brain.
In fact, as early as 2013, scientists proposed that brain-brain interfaces can achieve direct information transmission between biological brains. At that time, scientists initially proved that by recording electrophysiological signals obtained from the source brain in various ways and then influencing the neuronal activity of the target brain through intracortical electrical microstimulation (ICMS), animal A can imitate the behavior of animal B, with a deviation rate of only about 10%. Thus, the exciting concept of brain-brain interface emerged.
In the following years, several studies have achieved brain-to-brain interfaces between two or three human subjects through non-invasive technologies such as electroencephalography (EEG, a method of examining brain function based on the characteristics and changes of the brain's spontaneous bioelectric activity displayed by an electroencephalogram) and transcranial magnetic stimulation (TMS, a painless, non-invasive green treatment method in which magnetic signals can pass through the skull without attenuation and stimulate brain nerves), allowing the subjects to feel the perception of other subjects or the intention to move their fingers.
In addition, studies have shown that motor commands can be extracted from the human brain using EEG and transmitted to the brains of cockroaches or mice through electrical stimulation or focused ultrasound.
However, as mentioned above, brain-brain interfaces require multi-channel EEG recording, which is technically difficult. At the same time, EEG recordings are difficult to accurately decode, so the information transmission rate is low.
However, this research by Luo Minmin's laboratory has undoubtedly found a new breakthrough in the research field of brain-brain interfaces.
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About Luo Minmin
Seeing this, some people may ask: Who is Luo Minmin?
In fact, Dr. Luo Minmin is a senior researcher at the Beijing Institute of Life Sciences. Since he established his laboratory at the Beijing Institute of Life Sciences in 2005, he has published more than 40 academic papers in many international academic journals (such as Science, Cell, Neuron, and Proceedings of the National Academy of Sciences) as the corresponding author or first author, and his papers have been cited more than 2,200 times.
Leifeng.com learned that in addition to two neurobiological research directions (the encoding of olfactory signals in the mammalian brain and the physiological mechanisms of some basic animal behaviors at the neural circuit level), Dr. Luo Minmin is actually a "polymath". He studied psychology as an undergraduate and has also expressed interest in artificial intelligence, physics and other fields. Luo Minmin's laboratory has also developed many instruments in electrophysiology and chemistry.
In addition, Dr. Luo Minmin is also trying to challenge the widely concerned but controversial 5-hydroxytryptamine in the field of neurobiology. In fact, 5-hydroxytryptamine is serotonin, an inhibitory neurotransmitter that can affect almost every aspect of brain activity, such as regulating emotions, energy, memory and even shaping one's outlook on life. Some antidepressants work by increasing the level of this neurotransmitter in the brain.
There is no doubt that the process of scientific research is not smooth sailing, but Dr. Luo Minmin has always motivated herself:
Tell yourself every morning that there will be a big discovery today. Of course, most of the time I go home disappointed, but wake up the next day full of hope.
Perhaps it is this optimistic spirit that supports Dr. Luo Minmin and her laboratory to continue to make breakthroughs.
References:
http://engine.scichina.com/publisher/scp/journal/SCLS/doi/10.1007/s11427-020-1675-x?slug=fulltext
https://www.nature.com/articles/s41467-019-14116-y
https://baike.baidu.com/item/%E8%84%91%E8%84%91%E6%8E%A5%E5%8F%A3/17675124?fr=aladdin
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