What do we know about consciousness, and the unconscious? Can the progress made by neuroscientists help us better understand ourselves? In The brainYves Agid, professor emeritus of neurology, founder of the Brain Institute in Paris, answers all these questions, and many more. Interview.
L’Express: What is consciousness according to science?
Yves Agid: Most specialists agree that it is the highest and most important mental function for Homo Sapiens. On the other hand, scientists, psychologists and philosophers still do not agree to define what is called consciousness, the unconscious and metaconscience. Consciousness is to relate to oneself, as an internal mental representation of what one perceives. To fully understand what it is about, you have to have some knowledge of the amazing machine that is a brain. This machine, obviously more complex than a coffee machine, has two peculiarities: it is alive, biological and therefore adaptable, and it is able to produce thoughts and emotions. It remains to define what is called a thought. A thought is information, but information that is responsible for meaning. This information comes into the brain using the five senses (vision, hearing, etc.). Consequently, they are coded within it to produce behavior, which is expressed only by movement.
Consciousness can be defined as a thought on what we do, on what we perceive, even on what we are, that is to say on his identity. Metaconscience allows you to have a thought on what you think. It is a self -representation that allows you to control your own behavior. Which distinguishes us fundamentally from other animals. Without metaconscience, there would be no introspection and no morality.
And the unconscious?
To be unconscious is not to be aware, not to realize. However, the time spent relating to oneself, which is consciousness, is very short. However, the brain operates continuously, night and day. Conclusion: we think continuously, but we are not aware of it.
I used to distinguish three types of unconscious. First the perceptual unconscious. If I see an object, like a glass for example, visual information wins the posterior part of my brain (occipital cortex) in two tenths of a second. There, various groups of cells recognize the color, shape, topography of glass. My brain has recognized the glass … But me, not yet. For me to recognize the glass, it still takes two tenths of a second to allow me to realize that it is indeed a glass, the time that the information saves the anterior part of my brain.
This information is then processed in the brain, without any realization. This unconscious, the most important thing is truly the anteroom of consciousness. The information is sorted, hierarchized. Some are evacuated, and fortunately, otherwise we would go crazy! Others are kept in memory, completely unconsciously. From time to time, one of this information passes the threshold which brings it to consciousness. For example, you’ve certainly already managed to seek the name of a person and, at the moment, not to find him. However, the name of this person can come back to you later, when you think of something else. Between the moment you are looking for the name and the moment you find it, a job you are not aware of.
Finally, there is an executive unconscious. These are movements (gestures, habits, routines) to which you are not paying attention, which you are not aware of. For example, you are not aware of walking or driving your car, so many motor behaviors that have been learned and surappris. Fortunately, our unconscious is under the control of consciousness and metaconscience. This is the case when a new or unexpected situation occurs or if we were led to commit a morally unacceptable act …
In the book, you do not spare psychoanalysis. “Ideologies based on strange psychoanalytic interpretations, which are now over 100 years old, have never been validated and now seem very obsolete to the progress of neuroscience”, write …
I have nothing against psychoanalysts who have the merit of listening carefully to the sick. On the other hand, I am embarrassed by certain interpretations (the stages of the development of the child – oral, anal, phallic – the Oedipus complex, the death drive, for example) which were born in the brain of the brilliant Sigmund Freud, But who have never been validated. At the end of his life, Freud also recognized that he was only doing interpretations. It was over a hundred years ago. Today, when we start to understand how the brain works and how it dysfunction, I fear that these interpretations are no longer relevant.
The difficulty is that the general public often confuses psychology and psychoanalysis. The psychoanalytic approach is only a very particular form of psychology, and has never proven its effectiveness using the international criteria necessary to validate a therapy. The purpose of psychotherapy in the broad sense is trying to improve the failing functions of people with panic attacks, OBSS (obsessive compulsive disorders), delusions, etc. The objective is to reduce, and if possible to remove, the suffering of the patients by trying to understand the origin of the symptoms, and to help with if necessary drugs whose effectiveness has been validated. The use for more than fifty years of antidepressants, anxiolytics and antipsychotics, has enabled considerable progress in the management of psychiatric diseases, even if it is only a treatment of symptoms and not causes of these conditions.
For some of their detractors, neuroscience would only provide beautiful images of the brain …
Brain imaging has enabled spectacular progress in medicine. You should know that when I was internal, we did not even have to scan. Today, with the best machines, it is allowed to see the different brain structures with a precision of the cube millimeter! But in a cubic millimeter of nervous tissue, you have around 50,000 neurons and half a billion nerve connections. To understand more finely how the brain works, we must therefore try to understand how the dozens of billions of neurons in the brain manage to communicate with each other to produce thoughts and emotions. Not to mention the fact that neurons represent only half of the cells, since there are also non -neural cells (called glials), or the tissue located between the cells and the 600 kilometers of capillaries, all constituting a real “interior brain environment”.
Brain imaging is also an essential tool for research, but one day we want to hope to understand how the brain produces thought, that is to say the code of thought, we must reconcile the results of Brain imaging with clinical observation, knowledge of nervous circuits and their chemical content. This is the multidisciplinary approach that we develop at the Brain Institute in Paris. We will end up getting there … unless Homo Sapiens is not intelligent enough to understand the functioning of his own brain, which is a possibility.
The brain as a simple “machine” opposes the conception of the soul developed by great religions …
With the progress of science, we are forced to admit that our thoughts and emotions are directly produced by our brain. This brain is a machine of great complexity. It is like a huge computer, but which has the property of being changed continuously. Millions of nervous connections are made and defeat every second. This is what makes the brain perceive, learn, understand, have emotions, and realize it. We know the circuits fairly well, but not yet the code that allows the brain to produce thought. Soon we will find. Homo sapiens’ brain is about 7 million years old. However, it has barely been seventy years since IT has been discovered, and it is only for a few years that we have started to understand the functioning of the brain. You have to leave us a little time. Remember that Mendel’s laws on organic inheritance date from the 1860s. It was not until 1953 to discover DNA and the genetic code.
How do you explain that we still don’t know how to cure most psychiatric diseases?
The reason is due to the fact that, in psychiatric diseases, cellular dysfunctions are not visible when examining the brain using a microscope. Fortunately the nerve cells are not destroyed, but they work badly. This is not the case with neurological diseases which include holes (vascular accident), balls (tumor), inflammation (multiple sclerosis), losses of neurons (neurodegenerative diseases). In serious psychiatric diseases such as schizophrenia, autism, or severe depression, such lesions are not seen. So how to do it?
To better cure the scourges that severe psychiatric diseases represent, it is absolutely necessary to understand what is happening within the brain, and more particularly on the cell. When you have a car that doesn’t work, you look at what’s going on inside the engine. It is the same for the brain, knowing all the same that the human brain is a billion times more complex than an automobile engine. This is obviously where it is the difficulty!
But today, we have techniques that make it possible to detect these biological dysfunctions within nerve cells. Therefore, I am sure there will be a huge boom to treat psychiatric diseases in the years to come.
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