Source | Excerpt from The Biography of the Brain, by Matthew Cobb, translated by Zhang Jin, CITIC Publishing Group, March 2022.
Musk has just spent $44 billion to swallow Twitter, and he can't wait to announce his new progress in brain-computer interfaces. He revealed that it has obtained approval from the US Food and Drug Administration and will conduct human trials this year.
Musk revealed that he will conduct human trials of brain-computer interfaces within the year
Musk said neuralink, a company that specializes in brain-computer interface technology, can cope with health problems such as morbid obesity and even treat paralysis, stroke and brain damage.
Neuralink's plan for the next five years is for humans to communicate directly through their brains without having to use language. Musk also imagines that people can directly export their "memory" and "consciousness" through the brain-computer interface, and perhaps one day we can use USB sticks and memory cards to store their "souls" and realize people's "consciousness immortality"...
▲Neuralink brain-computer interface chip implantation (schematic)
Although many netizens believe that Musk is "drawing a big pie", the prospect of brain-computer interfaces should not be underestimated, and Neuralink is a good proof. Neuralink, founded in 2016, made $107 million in investment in 2017 and has a market capitalization of more than $500 million in less than six years.
In 2019, the global brain-computer interface market size has reached $1.2 billion, by 2020, this figure will reach $1.46 billion, and it is expected to reach $2.7 billion in 2026, with a compound annual growth rate of 12.4%. If you look at the application areas that brain-computer interfaces can affect, whether it is medical, education or consumption, it will bring a huge market space that far exceeds more than one billion US dollars.
▲ Musk announced the experimental results of monkeys using brain-computer interfaces
But in fact, Jacques Vidal, a professor at the University of California, Los Angeles, was not taken seriously when he first proposed the term "brain-computer interface" in 1973. Until an experiment was unexpectedly discovered, relevant experiments on cats could raise the seizure threshold.
Subsequent single studies also demonstrated that similar techniques can significantly reduce the chance of major seizures when applied to epilepsy patients. Such studies have attracted great attention in the clinical field, and imitators have flocked to it.
In just over fifty years, brain-computer interfaces have shown great innate advantages in the treatment of neurological diseases, and are widely used in other fields.
Brain science represented by brain-computer interfaces will change the future of mankind
Brain-computer interface technology is advancing rapidly.
The world's first cochlear implant was introduced in 1978, bringing the gospel of a better life for the hearing impaired. Today, cochlear implants are the most successful and clinically widely used brain-computer interface technology.
▲ The inventor of the world's first cochlear implant, Graeme Clark and the user
In 2011, Brown University in the United States successfully helped Cathy Hutchinson, who had been quadriplegic for many years, hold a bottle with a mind-driven robotic arm, slowly bring it to his mouth, drink coffee with a straw, and then put the bottle back on the table. For the first time in 14 years Hutchinson has been able to drink a drink entirely of his own volition. This experiment has ignited the hope of many paralyzed people to resume independent life.
Cathy Hutchinson controls the robotic arm with her brain
Three years later, in 2014, at the opening ceremony of the World Cup in Brazil, a 14-year-old paraplegic teenager, dressed in "mechanical armor", used his mind to control the movement of his lower limbs and completed the kick-off, which can be said to be a successful display of non-intrusive brain-computer interface wearable devices.
In 1978, The American biomedical researcher William Doberry implanted an array of 68 electrodes into the visual cortex of a disabled person who was blind after tomorrow, and a small camera was installed on the glasses to send the signal to a huge computer to decode, so that the blind subject could feel the light.
By 2020, Spanish scientists have enabled gomez, a blind man connected to a brain-computer interface, to see ceiling lights, people and letters printed on paper, basic graphics, and even play a simple mini-game.
In the | Gomez wearing glasses equipped with a camera. However, the brain implant device has been removed from her brain because it is still a temporary device.
While the results of brain-computer interfaces that have been achieved are exciting, the current achievable performance is still a long way from being envisioned in science fiction.
In addition to the limitations of the technical level, the more critical challenge is that our understanding of how the brain works is very limited. The continuous exploration and discovery of brain working mechanism by scholars in the field of brain science is the core foundation for the realization of brain-computer interface system.
In recent years, countries around the world have launched brain plans, such as BRAINInitiative in the United States, HumanBrainProject in the European Union, and Brain/MindsProject in Japan. As early as 2018, Beijing and Shanghai have successively led the construction of brain science and brain-like research centers, kicking off the prelude to the "China Brain Plan", and it is expected that in the next few years, the Chinese Brain Plan may have tens of billions of investment.
It is believed that in the near future, human beings are expected to make breakthroughs in brain research, thus bringing new opportunities for the further development of brain-computer interface technology.
Qiu Zilong, senior researcher at the Center for Excellence and Innovation in Brain Science and Intelligent Technology of the Chinese Academy of Sciences, said: "After entering the 21st century, brain science and related artificial intelligence and brain-computer interface technology are not only the most cutting-edge scientific fields at present, but also the science and technology that are most likely to completely change the future of human society. ”
All mankind is looking forward to a revolution in brain science, but breakthroughs in brain science face two difficulties.
First, the complexity of the brain is beyond imagination. Constructed from billions of cells, the human brain is the most complex structure in the known universe. We face challenges of this magnitude.
Second, while brain-related data from labs around the world is pouring in like a tsunami, we are in a crisis: the metaphor of comparing the brain to a computer seems to have failed, and we don't know what to do with it or how to interpret it.
Humans have the habit of using known "metaphors" for the unknown, and "the brain is a machine" is an example. After going through hydraulic power, clockworks, telegraph networks, telephone exchanges, and current computers, this "machine" metaphor is nearing the end of a crossbow, where do we go next?
But don't be pessimistic about the future of brain science, because in the history of human understanding of the brain, such dilemmas have occurred many times.
The most recent crisis was in the 1870s, when the metaphor of comparing the brain to a telegraph machine no longer applied, and the brain science community was full of doubts, and many researchers asserted that the nature of consciousness might never be deciphered. But then, the method of making the brain metaphor a computer came out, and people's cognition of the brain took a big step forward.
Science is constantly evolving, and each period of science is based on the integration, rejection, or transformation of the ideas of the previous period. A correct understanding of the past helps to understand the context of current theories and frameworks, and even to imagine how the future will develop.
So it is necessary to think, what kind of process has been experienced by human understanding of the brain for thousands of years. Can previous lessons be used to give us a more accurate and comprehensive understanding of the brain?
The historical context of brain science research
Shakespeare asks the question in The Merchant of Venice: "Tell me where love grows?" Is it in the head, or in the atrium? Now we know that the answer is "head," but historically "for the most part we thought it was the mind, not the brain, that is the basic organ that produces thoughts and feelings."
heart
From prehistoric times to the 17th century, scientists and wise men could not know the true function of the brain through observation, and they generally believed that thoughts and emotions came from the heart. For example, Aristotle of ancient Greece believed that the heart was the organ that produced sensations and emotions, and that the brain looked far less energetic than the beating heart. Ancient Chinese sages held similar views, so we have words to describe emotions such as "sadness" and "heartbreak".
Around 162 AD, the ancient Roman physician Galen proposed a shocking hypothesis about the brain. Galen experimented with a pig. He cut open the pig's chest and clenched the pig's heart, and the pig was still screaming; but when the pig's skull was opened and pressed against its brain, the pig immediately lost consciousness. Galen based on this to propose the brain-centered view.
At the same time, Galen also proposed an incomparably mysterious concept - "essence" (pneuma). He believes that this invisible and untouchable gas produced by the brain can flow through the nerves, which in turn controls the movement of the whole body.
Galen used pigs as an experiment to prove that thoughts come from the brain
Since Galen, more and more research has proved that the brain is much more complex than the heart, but the power of traditional inertia and everyday experience has led people to still hold the view of the center of the heart.
Bioelectric
By the 17th century, European thinkers were increasingly convinced that it was the brain that produced the mind.
Among the figures who emphasized the importance of the brain, the most influential was the French thinker Descartes. Descartes was right to think that Galen was right: there were indeed "spirits" in the brain that could move quickly, and these "essences" controlled the movements and thinking of the human body. Today, this can even be seen as a prototype of the brain's reflex arc.
In the 17th and 18th centuries, in addition to Newtonian mechanics, which revolutionized physics, there was another kind of study of forces that eventually unveiled the mystery of the brain— the study of electricity.
By the end of the 18th century, Italian scientists such as Luigi Galvani and Alessandro Volta were the first to reveal the wonderful power of electricity in living organisms. The ancient "essence" was finally found, that is, bioelectricity.
Galvani used electricity to make the frog's legs contract
The popular science bestseller "Relics of the Natural History of Creation", published in 1844, wrote that the connection between the brain, mind and electricity may be the most important sign that the public has learned about this idea.
Functional partitioning
In addition to the revolutionary discovery of bioelectricity, there was also a widely circulated theory in the 19th century - phrenology.
The main idea of phrenology is that since the brain is an important organ that controls behavior and even character and intelligence, the structure of the brain must be reflected by the skull that envelops the brain, so if you want to know a person's personality and even intelligence, you may be able to judge by touching the head.
Soon, due to the lack of support from experimental results, phrenology began to decline from the late 1840s. But from a scientific point of view, phrenology is not useless. The idea that certain functions of the brain are controlled by specific areas was later found to be supported by evidence.
In 1848, The American railroad worker Phineas Gage was pierced through the head by an iron rod that entered under his cheekbone and went out above his brow bone, blinding his left eye. However, he did not die, and did not even experience severe pain. Only then did his temperament change drastically, and Gage changed from an exemplary gentleman to a mean, violent, and unreliable person.
Scientists were inspired by his experience to propose functional partitions of the brain.
Phineas Gage holding an iron rod
In the two or three hundred years of the Enlightenment, scientists established a series of basic knowledge frameworks about the brain, including bioelectricity, functional partitioning, and so on. Brain research really became a branch of science until the end of the 19th century, when brain science research also entered the modern stage.
neuron
In 1858, the German pathologist Philsau proposed that "all cells come from cells", which seems to be a simple "cell theory", but it is an important hypothesis about the nature of human growth. Since then, Swiss anatomist Albert von Collik has proposed that the brain, like the rest of the body, is made up of cells.
But there is still a major controversy about how nerve cells are organized together. This controversy lasted until 1888, when the Spanish neuroanatomist Santiago Ramón Cajal proposed the neuron theory.
Cajal's neuronal theory put brain science research really on the fast track. By correcting the erroneous theory that cells in the brain are connected, and drawing up the staining map of brain cells that are now amazing to modern people, Cajal has always been regarded as the originator of modern brain scientists.
▲ Neurons observed and mapped by Cajal
Cajal and other researchers have found that neurons are independent structures, and that it is known that there is some kind of charge that travels through neurons, from dendrites to axons, just as telegraph or telephone messages are transmitted through wires. But how is the current between neurons transmitted?
In 1897, Charles Sherrington, winner of the British Nobel Prize in Physiology or Medicine, proposed the concept of synapses, and believed that the communication of information between neurons and neurons at this site became a breakthrough in understanding the way nerve impulses are transmitted.
In 1952, British scientists Alan Hodgkin and Andrew Huxley cleverly used a squid to discover the law of cell electrical conduction, which is the Hodgkin-Huxley equation, which explains the basic laws of neuronal firing.
This truly revolutionary discovery revealed the principle of neuronal firing, which is basically the transmembrane flow of sodium and potassium ions. Since this discovery, neurophysiology, as an emerging discipline, has officially entered the halls of science.
Brain is a machine?
In Paris, 1665, the Danish anatomist Nicholas Stannow gave a lecture to thinkers. Stannow boldly points out that if we want to understand how the brain functions and how it works, rather than just describing its components, then we should think of the brain as a machine and disassemble it to see how it works.
This is a revolutionary idea. For more than 350 years, the way we studied the brain followed Stannow's advice. His foresight profoundly influenced the study of brain science in the centuries that followed, and was at the root of the remarkable progress in our understanding of this extraordinary organ of the brain.
Humans have always used the habit of knowing "metaphors" unknown, so with the new discoveries of brain science, the metaphors for the brain are constantly being updated.
Earlier there had been a vague mechanical metaphor for the birth of the mind; after establishing an electrically based understanding of brain activity, the principle of describing the human mind based on battery theory was born; Sherrington's view of the brain, initially using metaphors similar to the steam engine, after accepting Cajal's neuron theory, was more inclined to the metaphor of the telegraph system, but gradually this metaphor was not enough.
The discovery of synaptic transmission enriches our understanding of neural function, but at the same time it also highlights a major concatenation: What new metaphors should be used to understand this working mechanism of the brain? It wasn't until 1940 that American mathematician Walter Pitts and neuroscientist Warren McCulloch spawned the most common metaphor used today to explain how the brain works: the brain is a computer.
But in fact, the initial human perception of the connection between the nervous system and electronic machines is reversed: people think of the computer as a brain. In brain science research in the 20th century, attempts were made to use machines to simulate and approach human intelligence. Pioneering thinking in this field led to the birth of the electronic computer.
Scientists have been hoping to use computers to simulate the brain's working processes, but a series of efforts to simulate the brain have been thunderous and rainy for more than half a century, and progress has been slow.
It wasn't until the beginning of the 21st century, when machine learning algorithms came out and the ever-increasing computing power began to rival human intelligence in some areas, that the era of artificial intelligence finally arrived.
The challenges of the future of brain science
Looking back at the thousands of years of brain research, the field of brain science has interesting characteristics compared to other life science fields. These uniquenesses determine the major challenges scientists will face over the next hundred years.
One challenge is dissecting the structure of the brain.
Compared with the heart, stomach and other organs, the structure of the brain is obviously the most complex. Going down to the molecular and cellular level to dissect such complex structures is the biggest challenge scientists will face in the coming century.
In the face of this challenge, scientists have proposed several solutions, such as the first generation of brain connection group programs that have actually failed. Scientists proposed the plan more than a decade ago to reconstruct the brain with an electron microscope, and it took more than 5 years to figure out an area of 0.013 cubic millimeters in the mouse brain.
There are as many as 70 million neurons in the mouse brain, and the most comprehensive map of mouse neuronal connections has only reconstructed the connections of less than 2,000 mouse neurons, while the human brain has 100 billion neurons! This is clearly an impossible task.
Another challenge in brain research is to parse how the brain works.
Although the structure of the brain is extremely complex, dissecting the structure of the brain is still only an engineering problem, even if it may take hundreds of years for humans, at least it seems to be achievable. The real test for scientists is figuring out how the brain works.
For example, how are memories generated and stored; how is human consciousness different from other animals that give humans the uniqueness of being human; and how are complex human behaviors and even mental states controlled? Not to mention the specific mechanisms of the many brain diseases that doctors and scientists are currently helpless to do – Alzheimer's disease, schizophrenia, autism and so on.
The most dazzling jewel in the crown of brain research is the principle of these advanced cognitive functions. We don't yet have answers to these questions that will satisfy everyone. We are all looking forward to the arrival of truly "revolutionary" discoveries.
The Legend of the Brain
By Matthew Cobb, translated by Zhang Jin
CITIC Publishing Group, march 2022
This article is excerpted from the "Biography of the Brain", which takes the metaphor of the brain as the starting point, introduces the multiple milestones in the history of human cognition in the history of brain cognition, and the scientists who have made great discoveries, and tells the profound impact of brain science research on the birth and development of computers, artificial intelligence and other fields.