The fact that we are a collection of many cells that take on a very specific form and are endowed with a wide variety of functions does not mean that this entire biological cluster must be self-aware. In fact, we are not only a collection of our own cells. There are trillions of bacterial cell compounds in our body.
In this way, we are like a “bag” of various cells, both self and foreign, which are held together by the complex mechanisms of our immune system. Why, then, do we think of ourselves as a single, unique being? Obviously, we are aware of our own existence as an individual person. Moreover, we were born with the ability to remember everything that happened to us over time. Both our consciousness and our memory are rooted somewhere in the network of cells in our nervous system.
The brain is self-awareness
The importance of the brain for our self-awareness is illustrated by a simple example. Under various adverse circumstances, people can be left without limbs. Due to injury or illness, their spleen, kidney, lung, most of the intestines can be removed. They can also replace the heart, liver, kidney, or other organs with a transplant.
It is clear that we can be left without many parts of the body, which implies the absence of billions of cells that were involved in these organs. However, we still retain our self-consciousness as a single being. The only part of our body that we really cannot remove if we still want to feel awareness is the brain.
We still don’t know how to repair damage to the brain or any damage to the spinal cord or nerves. It is important to note that we have understood the exact function of the other organs of our body from their cellular structure. Everything that happens in our other organs resembles a very elegantly designed biological machine. But we cannot understand the functions of the brain in the same way. The nature of thoughts, consciousness and their material basis remain elusive to science, at least for the moment.
In his 1968 masterpiece 2001: A Space Odyssey, Stanley Kubrick presciently pointed out the problem. If humanity continued to develop ever more sophisticated technologies, but without a solid understanding of what consciousness is and how it arises, it would be difficult to predict where this might lead. Kubrick and Arthur Clarke , the leading science fiction writer of the day, wrote the screenplay together. Fifty years ahead of their time, they foresaw the problem that preoccupies many scientists today: can we continue to develop computers and artificial intelligence in the absence of a sufficient understanding of the material basis of consciousness?
In Kubrick’s iconic film, the spacecraft is controlled by a computer called HAL 9000. It was supposed to be non-judgmental, but during the journey it begins to show signs of its own consciousness. As a result, he ceases to obey the orders of people. The computer began to show emotions – for example, the fear of being turned off. This interesting story, which in 1968 seemed pure fiction, today is of genuine interest to many scientists.
Elon Musk, founder and owner of SpaceX and Tesla, Peter Norvig, director of research at Google, recently deceased physicist Stephen Hawking , as well as the founders of artificial intelligence companies DeepMind and Vicarious and about 150 other scientists, signed an open letter in January 2015, in which they jointly warned the public about the danger of developing something that is potentially so powerful and superior to humans that we could lose control over.
Self-awareness of artificial intelligence
At the heart of the fear of artificial intelligence lies the fact that today’s science still does not understand what consciousness is, how it arises, and how we can properly study it in general. In nature, there are many so-called “emergent phenomena” that arise spontaneously when something underlying them becomes sufficiently complex. For example, in a large wheat field, due to the large number of ears, wind waves will begin to arise. Similarly, flocks of birds will create beautiful undulating patterns in the air.
What worries some scientists today is that consciousness can also be an emergent phenomenon—a consequence of our large number of neurons, their interconnections, and the electrical impulses in the brain. If this is true, then the increasingly sophisticated modern computers that support artificial intelligence may at some point also gain awareness and undo their subordination to us, their creators.
Artificial intelligence has already proven its superiority over human intelligence on many levels, so this development could be catastrophic for humanity. Therefore, it is of great interest for modern science to penetrate as soon as possible into the material foundations of consciousness.
In recent years, several interesting studies have been published to this end. There have been examples of patients with so-called brain stem injuries. The brain stem is the part of the nervous system that connects the brain to the spinal cord. And, perhaps, hides the secret of the state of wakefulness of the body. Some patients with brain stem injuries are completely unconscious, in a deep coma, while others manage to remain conscious despite the injuries. With in-depth scanning of their injuries, scientists associate the preservation of the function of brain stem sections with the preservation of consciousness, and the damaged areas with a coma.
Where does your own awareness of yourself as a person come from?
In this way they try to discover “where” self-consciousness is physically rooted in the nervous system. But consciousness is not easy to define, although we all intuitively know what it means. Namely, it is not only a state of alertness and reaction to external stimuli, but also includes the impression of one’s own unique existence. Where does this impression come from?
Another question remains – how and why does consciousness “turn on” and “turn off” when we wake up and sleep, and how can the entire brain be taken out of a full-fledged sleep in a fraction of the time, given all its structural complexity? One possible answer lies in the recent discovery of giant neurons that arise from the so-called “claustrum,” an area of the brain where the concentration of various pathways and connections is greatest and is considered perhaps the most important signal integrator in the brain. These giant neurons wrap around the entire brain like a crown of thorns.
They interact with all external surfaces of the brain, that is, wherever the gray matter is located. Therefore, these neurons could somehow “turn on” and “turn off” the entire brain. But why is it necessary to turn consciousness on and off at all, and what is its material, i.e., biological, physico-chemical basis? These are questions about which we still know very little.
We can only hope that our understanding of this issue will expand significantly in the coming years. This should help us prevent, or at least learn to control, the development of consciousness in the increasingly complex computers we develop.
In the meantime, we can at least try to recall some of the most significant discoveries and breakthroughs made so far in the field of nervous system research. Despite continuous progress, it would still be inappropriate to claim that we understand well enough how the nervous system works and gives us a sense of the existence and uniqueness of our entire organism, consisting of so many tiny parts.
Discoveries of Camillo Golgi and Santiago Ramón y Cajal
Let’s start by remembering two real giants – the Italian scientist Camillo Golgi and his Spanish colleague Santiago Ramón y Cajal – who received the Nobel Prize in Physiology or Medicine in 1906. In the previous 19th century, scientists learned to stain tissues so that they could be better seen under a microscope. Golgi discovered that cells of nervous tissue, neurons, can be stained with silver nitrate. This led to the first significant understanding of the structure and function of the nervous system.
Golgi believed that all nerve cells in the body form a continuous network and that they are all physically interconnected in this network. Ramon y Cajal disagreed, although he also used the Golgi neuron staining method. He proved that each nerve cell is completely independent of the others. He realized that individual neurons do not belong to a single large physical network. Instead, the impulses transmitted along the nerves pass through the so-called synapses, that is, the points of communication of nerve cells isolated from each other.
Nobel laureates Charles Scott Sherrington and Edgar Douglas Adrian
Then it took more than a quarter of a century for another Nobel Prize in this area. In 1932 it was presented to English neurophysiologists Sir Charles Scott Sherrington and Baron Edgar Douglas Adrian. At that time, they already understood quite well that the functions of our body are controlled by the nervous system, which consists of many nerve cells, that is, neurons and their processes. They also knew that neurons form a network of connections between them and that they connect the brain, spinal cord, and the rest of the body.
Stimulation of nerve cells can in some cases lead to muscle movement without any influence of our will. This is unusual because the same muscles are usually under our direct control. That’s why we call these uncontrolled muscle movements “reflexes.” Sherrington showed how muscle contraction is followed by relaxation, and that muscle reflexes are only part of a much more complex system.
In this system, the spinal cord and brain process the impulses that come to them. Then they can convert them into new impulses without the role of an arbitrary component and send these impulses to the muscles and organs.
Adrian’s merit is based on understanding the signals in the nervous system, which are transmitted by very weak electrical currents. Adrian was able to develop methods for measuring electrical signals in the nervous system. He realized that the electrical current in neural connections, as well as the signals passing through them, always have the same strength. Therefore, oddly enough, how we perceive a stimulus from the environment as stronger or weaker does not depend on the strength of this current. This will depend on how often these electrical signals are sent and the number of nerve endings through which these signals are transmitted.
Research on the transmission of nerve impulses
In 1936, the English physiologist Sir Henry Hallett Dale and the German pharmacologist Otto Levi were awarded the Nobel Prize in Physiology or Medicine for their discoveries related to the chemical transmission of nerve impulses. They knew from their predecessors that nerve signals are transmitted by electrical impulses. However, it was unclear whether chemical processes also play an important role in the signaling of the nervous system.
Dale discovered that acetylcholine stimulates a part of the nervous system called the parasympathetic system, which calms the heart and other processes. Levy demonstrated that acetylcholine is an important mediator between nerves and organs at their points of physical contact. He proved this by stimulating the frog’s heart with electrical and chemical stimuli.
Discoveries in the field of neurophysiology. Laureates Joseph Erlanger and Herbert Spencer Gasser
These significant breakthroughs were followed by another discovery that also won the Nobel Prize for American neuroscientists Joseph Erlanger and Herbert Spencer Gasser in 1944. They studied the characteristics and distribution of nerve branches throughout the body very carefully. Based on this, they divided the nerve fibers into two different types, differing in thickness, and showed that thicker nerves conduct impulses much faster than very thin ones.
After important progress in this field of science, there was again a lull, which lasted another quarter of a century. This was followed by a stage of recognition for the discovery of the so-called “neurotransmitters”. These were chemicals important for the transmission of information in the nervous system and its proper functioning.
In 1970, the German-Australian physician Sir Bernard Katz, the Swedish physiologist Ulf von Euler, and the American biochemist Julius Axelrod were awarded for the discovery of several key neurotransmitters in the nervous system, as well as their storage, release, and suppression mechanisms. Numerous neurons have their processes – nerve fibers. Signals pass through these fibers thanks to very weak electrical impulses, as well as thanks to the so-called signaling substances – neurotransmitters.
Katz investigated how impulses from neurons fire muscles by measuring differences in electrical voltages. This led him to demonstrate how the neurotransmitter acetylcholine is released from synapses. Ulf von Euler discovered the neurotransmitter norepinephrine, which plays a very important role in the transmission of impulses for the choice of fight or flight. He showed how norepinephrine is created and stored inside the bladder, and how it sends a signal from one neuron to another across synapses.
Study of norepinephrine
Their colleague Axelrod, on the other hand, was studying norepinephrine, a signaling substance that stimulates increased activity in the event of aggression or danger. He showed that excess norepinephrine is released into the blood in response to signals from the nerves. It then returns to the vault again.
Discovery of dopamine
At the turn of the millennium, in 2000, the Swedish neuropharmacologist Arvid Karlsson, the American neuroscientist Paul Greengard, and the American-Austrian neuroscientist Eric Kandel were awarded for further discoveries of neurotransmitters in the nervous system. Carlsson discovered dopamine in the brain and its role in a person’s ability to move.
This explained the symptoms of Parkinson’s disease and allowed new treatment strategies to be developed. Greengard elucidated how signaling substances function in the nervous system by showing how they first act on a specific receptor on the cell surface.
The protein molecules are then modified by adding or subtracting phosphate groups. It is a mechanism for regulating many functions within the cell. Kandel explored how memory is stored. While studying sea snails, which have a very simple nervous system, he realized that snails can still learn. This is because chemical signals change the structure of connections between nerve cells, i.e. synapses.
Building on this important discovery, he went on to demonstrate how short-term and long-term memories can be formed through various cues. This mechanism is common to all learning creatures, from sea snails to humans.
All of these discoveries have helped us better understand some of the most fundamental principles and mechanisms of how the nervous system functions in the body, as well as its interaction with organs. However, how the brain itself functions remains a mystery. The Swiss physiologist Walter Rudolf Hess was awarded the Nobel Prize in 1949 for his discovery of the functional organization of the midbrain, the so-called “midbrain”, as a coordinator of the activities of internal organs.
In his experiments, he injected a very thin metal wire into different parts of the midbrain of an anesthetized cat. When the cat woke up, he could induce him to various actions with the help of very weak electrical impulses. At the same time, he observed not only simple reactions, but also rather complex forms of behavior, including defensive or aggressive behavior.
Roles of the cerebral hemispheres
The American neurophysiologist Roger Sperry, who received the Nobel Prize in 1981, also made a significant discovery related to the workings of the brain. He knew that in the brains of humans and animals, there are two hemispheres with slightly different roles. Sperry sought to understand the role of each hemisphere by examining patients who had intentionally damaged the nerves connecting the two hemispheres of the brain. At the time, damage to these nerves was a form of treatment for severe epileptic seizures.
Through his observations, Sperry realized that the left hemisphere is more occupied with abstract and analytical thinking, arithmetic, linguistic expression, and language learning. The right hemisphere is more important for navigating through space and for understanding complex sounds and messages such as music.
In the 21st century, every year we understand more and more how the brain works. Perhaps the European Commission’s most ambitious project, worth a billion euros, has won an award for creating a computer model of part of the cerebral cortex. It was expected to model how the many connections between all these neurons work and what they actually do. At the same time, new theories of consciousness are emerging, for which a method of experimental verification has yet to be developed. However, in contrast to the very significant advances in understanding the functions of all our other organs and systems, we are still very far from a correct understanding of how the human brain works. That is why it is reasonable to expect that at least some of the Nobel Prizes of the 21st century will continue to be awarded for significant breakthroughs in this field.