A moment after Yossi gave Rina a book * How are we able to build many different shapes from a few lines, and assemble an infinite amount of sentences and ideas from a small number of syllables or sounds? A theory conceived by Prof. Moshe Abels has now been strengthened by biological experiments
Merit Sloin
How does the brain work? How does it process information? How does he filter the multitude of information that reaches him from the senses and how does he make it possible to understand the meaning of language? These questions represent only a small part of the mystery surrounding the black box that resides in everyone's body. The last decade of the last century was devoted to brain research. Tens of thousands of people have been studying the brain for many years and each of them poses a clear scientific question. A huge number of details accumulates, but the things do not connect together and do not lead to a thread that will allow progress in understanding how the brain works.
Progress in understanding the brain will not come by chance by inventing a new idea, says Prof. Moshe Ables, director of the Gonda Center for Brain Research at Bar-Ilan University and a member of the Center for Neural Computing at the Hebrew University. "It is necessary to feel the behavior of the system in order to understand why what is being done today is not enough. A new theory may be needed to understand the mind, but it will only emerge from people who understand what the mind is and how it behaves. The hope is that someone clever and creative will come up with it. But in order to create the scientist who will make a change in thought, it is necessary from an early age to educate for interdisciplinary thinking in brain research, which will include studying fields such as physics, psychology, computers and, of course, neurobiology. The integration of all these areas will make it possible to understand the behavior of a system consisting of many details that have mutual relations between them."
But, according to Ables, the academic community is conservative. Although she understands that interdisciplinary education is needed in the field of the brain, she resists changes. Some universities have started to implement an interdisciplinary master's degree program, but only a few are accepted. At Bar-Ilan University, an interdisciplinary brain research center is being established that will educate in interdisciplinary thinking starting with undergraduate studies.
Abels has been researching the brain for 44 years. "The real question that interests me is how the more complicated operations are carried out in the brain," says Ables. "For example, how are we able to build many different shapes from a small number of lines, create a multitude of physical gestures by combining a small number of simple movements, compose many melodies from a small number of notes, and from a small number of syllables or sounds compose an infinite amount of sentences and ideas ?”
It is possible to distinguish the brain in the areas responsible for vision, and within them areas that are sensitive to straight lines, those that are sensitive to simple shapes and areas that are sensitive to complex shapes such as faces. There are areas in the brain responsible for hearing, which receive the appropriate messages from the environment and create the audio image. "In each of these areas, the picture consists of simple to complicated elements, but there must also be another organization that not only builds something complex from individual elements, but can provide understanding and the creation of a new idea," says Ables.
"For example: when we hear the phrase 'Yossi gave Rina a book', we immediately understand its meaning. The assumption is that in the brain, groups of cells are activated that represent Yossi, Rina, the book and the act of giving. When we hear this sentence, each of these groups increases its activity. But if that's all that happens, then where is the understanding of who gave whom the book? Comprehension, or in other words the assembly of an idea from simple words, is the central problem of understanding thought processes".
Science has not yet answered this question. According to the existing approach, everything that exists in the world has a representation in the brain, so when you think about something or see something, the area of the brain that represents the object is activated. The activation is expressed by the fact that the rate of activity of a group of nerve cells in this area increases. Although in each group only the cells that represent a certain object are activated, the exact timing of the activity of each and every cell is random, and what determines is the average rate of activity of all cells.
"This approach provides an explanation for simple actions," says Ables. "For example, when you look at a single line on a white background. If the line is balanced or vertical, different cells in the brain increase their rate of activity. The problem arises when there are several lines, for example those that connect together to form a triangle or a square. The brain needs to know which of the lines belong to a triangle and which to a square. The explanations for this today are complicated and fail to explain how we manage to identify who is a triangle and who is a square when they partially hide each other or when they are transparent and visible on top of each other. In life there are many objects with partial concealments. How do you know which lines belong to which object? Not only do they not understand how the brain does it, but also computer systems that try to decipher a photograph in a structure where objects hide each other fail. How the simultaneous integration of the knowledge that exists within us with the information that comes from the eye to create a general picture - is a puzzle. This is actually the same type of problem as 'Yossi gave Rina a book' - we don't know how to connect the components to understand the meaning of the sentence.
"Apart from all these, the existing explanation does not seem plausible because it cannot be that every concept or object has a representation in the brain. A simple calculation shows that there are not enough cells in the brain for this. There must therefore be another approach that will give the answer to the more complex operations, so that each cell can participate in many processes."
In the seventies, Ables developed for the first time a technique that made it possible to simultaneously measure the activity of six nerve cells in the brain of animals while performing various actions. The observations of the animals' behavior and the activity of their nerve cells revealed a new phenomenon: from time to time some nerve cells worked in order and at regular time intervals. For example, cell A started working and after 36 milliseconds cell B and after 92 milliseconds cell C. This series has repeated itself again and again in a way that cannot be explained as mere coincidence. "Since this phenomenon could not be explained based on the existing knowledge, I built a model of a neural network that can explain the phenomenon", Ables says.
According to the model he built, the cells are organized in groups. All the cells in one group work at the same time. This group of cells activates another group in which all the cells also work simultaneously, and so on. Ables called the organization a "chain of sharp shooting". "I tested the model theoretically. At first with paper and pencil and then in a computer simulation, and I came to know that the idea is correct and can work, and since then there is a whole school of research that deals with the sharp-shooting networks and shows more of their properties", says Ables.
In the early 90s, Prof. Eli Binenstock, from Brown University in Providence in the United States, proposed that by coordinating times between the chains of sharp firing, it is possible to build representations of complex things from their simple elements. "A short time later, we showed with the help of simulations that these chains can actually fit themselves together and connect to each other like Legos," says Ables. "Complicated structures can be built from this and dismantled again. This also makes it possible to explain the 'Yossi Varina' phenomenon. If the action 'give' contains three components ('the giver', the 'receiver', and the 'given object'), then the cells that represent Yossi will work simultaneously with the part of the 'giver', and whenever the cells that represent Rina work, they will also work The cells representing the 'receiver', while the book cells will operate simultaneously with the 'given object' cells. And so it will be possible to represent the meaning of the sentence".
The subject of the sharp firing chains and the timing between them is hotly debated in the scientific world. The debate begins with the question of whether precise timing of nerve cell activity actually exists in the brain. In the research currently underway, Ables, together with a team of researchers from Bar-Ilan University, was able to unequivocally demonstrate that such precise timing does exist in the brain.
The second question is, if chains of sharp firing are the only way to explain the series of precise actions, or maybe there are other networks in the brain that can also create precise timing. There is still no answer to that. But the question of the questions is, are the chains of sharp firing and the timing between them the basis of our understanding, or is it a meaningless side effect. A "feasibility test", conducted in recent years by Gabi Hayon from the Hebrew University, showed that the idea could work in the nervous system. What was missing was the experimental proof that this is what actually happens in the nervous system.
"The difficulty in experimental proof is the limitation of our ability to measure," says Ables. "In every cubic millimeter of a person's cerebral cortex there are 20 nerve cells connected by four kilometers of branches and eight billion contact points. It is impossible to see directly what is happening there, therefore our testing ability is limited to individual nerve cells".
Two weeks ago, a research paper by a team led by Prof. Raphael Yost from Columbia University in New York was published in the journal "Science". The researchers put mouse and rat brain slices in flasks in a physiological solution and found a way to simultaneously record the activity of about a thousand nerve cells from each slice. The experiments yielded two unexpected phenomena. One testified to cell activity repeating itself precisely (as in series A, B, C described above). Each such series indicates, according to the researchers, an organized activity in a chain of sharp shooting. In addition, they showed that the series connect to each other in a fixed order. "If we imagine each such series as a musical motif, then the researchers found complete melodies that repeat themselves. These findings contradict the popular view that the processing of information in the brain is based on a general change in the rate of action of groups of cells without a precise order, but align well with the idea of organizing the activity with the help of chains of sharp firing," says Ables. "If this is indeed the case, then before us is a transformation in the understanding of the neural mechanisms underlying processes such as understanding the world around us, thought, or language."
