6
At that time, my most talented friend, Mika Bongard, and the most hardworking, Misha Smirnov, were actively studying the workings of the frog retina. They chose the retina, the most convenient part of the brain, for the experiment. They made a complicated amplifier with their own hands and convincingly proved that frogs have color vision. Namely: under no selection of the intensity of light falling on the isolated retina, it is impossible to replace it with light of a different wavelength so that electrical signals do not appear in the fibers of the optic nerve, signaling this change to the brain. All nerve impulses are the same: the same amplitude, the same duration.
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Efim Liberman (left) and Mikhail Bongard in the early 1950s.
How is information about color transmitted to the brain?
With the consent of my friends, I tried to answer this question. As early as the beginning of the twentieth century, the English physiologist E.D. Adrian had shown (Adrian, 1912), that in response to stimulation of various sensory organs, a series of impulses is transmitted along the nerve fibers. The stronger the irritation, the longer the series and the more frequently the impulses appear within the series. However, until the middle of the twentieth century only one explanation was conventionally accepted: signals about different patterns of irritation go along different fibers.
I recorded the timing of the electrical impulses that occurred when the retina was illuminated with different wavelengths of light using an alpha-counting amplifier made by the whole institute.
And the microelectrodes were made for me by the wonderful master Modest Weinzweig, so it was easier for me than for anyone else to find out how information about the intensity of light and about its color is encoded in single fibers. Codes containing such information are sent by special retinal ganglion cells. "Red" codes are always shorter than "blue" ones (see Fig. 1).
Figure 1. Retina reaction to illumination. Codes containing such information are sent by special retinal ganglion cells. "Red light always initiates shorter codes than blue light” (Liberman, 1957).
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Color detectors
Two years later, the American physiologists W. Hubel and H. Wiesel found cells that, at the illumination intensity they used, responded with several pulses to the movement of the spot along the retina in one direction and did not respond when moving in a direction perpendicular to the first (Hubel, Wiesel, 1959). They called these cells "detectors" of movement, and since then the term has been applied to neurons responding to increasingly complex images. In terms of this concept, the cells we discovered could be called "color detectors". However, this name distracts from the meaning of the studied process of coding messages in the fibers of the nervous system. Complex messages are transmitted along single fibers using uneven distribution of identical electrical impulses over time.
Information is a word that is often mentioned these days. Its scientific meaning is that messages can be encoded.
The neuron is capable of sending electrical impulses at intervals specified by the solution of tasks. This is the extreme way of encoding: only via duration of time intervals. Usually, an alphabet of several characters is used. Since they can be put in any order, all kinds of permutations can be used for encoding. It is so simple that people often forget to even say it, instead it is taken for granted. Only macroscopic signals can be swapped. There is no such a possibility in the quantum world. There, elementary particles can appear and disappear independently. Therefore, the concept of information refers only to the macroscopic area. In addition, this is a purely mathematical concept, since physics assumes that the future of the system depends only on the past. Science defines the concept of "amount of information". This value indicates the length of the code. If the number of transmitted messages is N, then the code length is logₐN, where "a" is the number of characters used for encoding. The creator of information theory, Claude Shannon, was an engineer at the Bell System telephone company. The fact that the length of the code is a logarithm had been discovered many years before. His main idea was also simple: code short what you transmit frequently, and code long what is transmitted rarely. Then, on average, the line will be less loaded. Hence the famous formula for the amount of information, at first glance, seems similar to the equally famous formula of thermodynamics.
When I saw the difference in color codes on the oscilloscope, I jumped for joy. But the joy was premature.
Friends did not want to be co-authors of the paper, and in general they claimed that I had misunderstood them and invaded their field of science. I left this field, otherwise I would have been studying the physiology of vision all my life, and trying to understand how the generator of electric current in the membrane of nerve fibers works. Fortunately, soon Mika Bongard reported our work on color coding at the seminar of Academician Pyotr Kapitsa, who was already back after falling out of grace for refusing to make an atomic bomb, and after the seminar we drank tea with him. Soon after this tea I was invited to his home by Academician Yakov Zeldovich, who had finished his atomic affairs and decided to deal not only with the origin of the Universe, but also with the mechanics of vision. Zeldovich met me with joy: he knew how to solve this problem. Apparently, Kapitsa told him about Mika’s talk – his reports had fascinated the scientific audience.
When I told him about the experiments, Zeldovich became sad: it was far from theory, and he quickly said goodbye. [As I realized much later], theory in biology is just DNA texts.
Efim Liberman in the 1960s.
chaimatics
Chaimatics
Discovery of links between the biology, physics and mathematics, and founding a new area of studies focused on computations in living systems are his life achievements. Efim Liberman gave the name of “Chaimatics” to this new area of science
I
DNA is the text of a code written for molecular computers of living cells. The notion of “Text” is intrinsically opposite to a random sequence of symbols, and it can exist only inside the system of language. In this case, it is a genetic language, which is isomorphic to a natural language
II
Computations conducted in a living cell are real physical actions, and free energy and time must be spent for completing them. As all living organisms are comprised of cells, this statement is applicable to any control processes implemented in the biosphere
III
Molecular computations are limited by the microscopic scale of a cell and inevitable impact of the computations on formulation of a problem begin solved. The Chaimatics grew from the recognition of the computation reality as the quantum mechanics grew from the recognition of the measurement reality.
IV
A cell creates а quantum computing tool for solving complex problems. This tool utilizes hypersound quanta, and uses the cell cytoskeleton as the computing environment. In such a computer, a price of elementary computation converges to the physical limit, which is Planck’s constant
Chaimatic's statements are simple, but they require a change in the traditional vision, rooted in scientific practice
Read a book
Chapter I
The journey of life in science
chaimatics