Brain models

The human brain uses about 20 per cent of the body’s energy but is just two per cent of its weight. In proportion to the body mass, the brain is three times as large as that of our nearest relatives. It has more than ten thousand million neurons, interconnected by means of a thousand times this number of synapses. Due to the speed with which biological membranes function this gives around 1016 interconnections per second. This is around one billion times faster than today’s most powerful network computers. The most complex interconnective communication system in the world is the global telephone system — carrying only 1011 calls per year.

For some reason or other the human race emerged with this brain, oversized in performance compared to the needs of the bodily functions. This extra capacity was the basis for the extremely complicated nerve functions necessary for verbal communication. The richness of internal interconnections enables the owner of the brain to use symbols and therefore permits the development of a language.

The human brain has between 10 and 100 billions neurons and each of them are interconnected with 1000 to 20000 other neurons. The number of possible interconnections between them thus exceeds the number of existing atoms in the Universe. As a survival instrument adapted to the world surrounding us, the brain therefore probably is the most complex system which exists in the universe (with the exception of the universe itself?) because it can form a representation of the enormous complexity of the surrounding world.

Today, a common belief among brain researchers is that the more the brain is used the better it will work. Intense use will cause the branches, called dendrites, in the neuron to grow. Dendrites are rootlike projections connecting the neurons. A typical neuron receives input signals from tens of thousands of other neurons. The more dendrites, the more interconnections promoting information transfer between different parts of the brain. Although divided into areas, each with a specific function, the brain processes information mainly in the same way in all of these areas.

Studies of the brain have shown that the length of dendrites may vary by as much as 40 per cent between different individuals. A most intriguing finding is that those who pursue intellectually demanding jobs have longer dendrites than those who do not. Two possible explanations for this phenomenon are: intellectually challenging lifestyles cause dendrites to grow longer or having long dendrites leads people to live intellectually challenging lives. The first alternative, considered to be the most plausible, has received support through experiments with animals: rats raised in ‘enriched’ environments have been reported to show changes in brain structure.

A widespread attitude among researchers is that the brain is so complex that it will be impossible ever to embrace its whole function and capacity. A classic paradox formulated by the biologist Lyall Watson is: ‘If the human brain was so simple that it was possible to understand its function, human beings would be so simple that they could not understand it.’ It is a common view that the brain is a system which cannot be worn out; the brain grows with activity and will only be better by increased use. It is also assumed that we normally use only approximately one per cent of its total capacity.

The brain’s storage capacity is literally astronomical and researchers believe that it can store every impression during a normal life-span — with plenty of room left over. This statement that the brain can store every impression it has come in contact with applies to either of the two halves of the brain (or one of the two co-operating brains); like other essential mammalian organs, such as kidneys and lungs, it is duplicated. But unlike other doubled organs where each half of the pair works on equal terms, the brain pair is individually specialized with an established internal hierarchy.

The left brain seems to be specialized in serial information processing, while the right works primarily in parallel. Verbal processing and writing via letters, words, sentences, sections and pages is typically assigned to the sequential and analytical left side. Associative work seems to be assigned mainly to the synthesizing right side. Typically, this side processes more than seven elements in a very short time. It also recognizes musical patterns and chords and discriminates pitch as well. It discerns the form of the whole from its parts and recognizes complex visual forms (pattern recognition). Accordingly, two different kinds of information input may be treated simultaneously, compared and co- ordinated by both halves, thus creating a substantial and all-embracing impression. Functional differences between the left and right side can be listed as follows:

There is also strong evidence that women have a better integration of the halves than men.

When the two halves of the brain become separated by accident or brain surgery (split-brain), the result is the emergence of two personalities, both with their own information sources and individual self-consciousness. Experiments with such persons involving screened- off vision show that an object held in one hand cannot be compared with a similar object in the other hand. There are simply no connections between the two eyes. When the artificial shield between the eyes is removed the two personalites are joined again to a single personality. The separated hemispheres have simply so many secondary interconnections via the brain-stem that their activities once again can be co-ordinated.

Within our Western-culture an old tradition of analytical and rational thinking is coupled with a need for adequate expressions in speech and writing. The capacity for artistic work, intuitive thinking and creative fantasy is often seen as something less essential for both personal and societal development. From that point of view the left side dominates, sometimes creating the typical modern rational personality (sometimes with a touch of neurosis). For a harmonious development of the personality, society and its educational system must assign equal significance to the capacity of both left and right brain halves.

When discussing the over-arching organization of the brain, a rare quality existing in certain people must be mentioned. Known for more than 300 years, it is called synaesthesia and can be described as a multisensory integration in the experience of the surrounding world. Persons with this quality have a sensory crossover which makes them able to experience words, sounds, smells, sensations, etc. as coloured. The experience is involuntary and cannot be suppressed. Those with this faculty find their experience quite natural and can rarely understand that this mixing of senses does not occur in others.

Apparently, synaesthesia is a normal brain function in mankind but, for some reason or other, its working reaches conscious awareness only in a handful of people. It suggests that the brain has some kind of co- ordination centre where recall is reconstructed from numerous fragments of memories, stored separately, but accessed in an integrated way.

One of the best known concepts of the mind, called the parallel distributed processing (PDP) brain-model, is embraced by several neuroscientists (see D. Rumelhart 1986). According to this model, intelligence emanates from the interaction of a great number of interconnected elementary units, the neurons. This slow and noisy apparatus performs real time processing the only way possible: by working massively in parallel. Such a working mode means that a sequence, requiring millions of cycles if it were to be processed in a serial way, is done in a few cycles in a network of a hundred thousand highly interconnected processors.

In this model, the brain work is regarded as a statistical process; no specially important areas are commanding the decision-making procedure. Decisions are made through co-operation between independent units, the neurons, creating reliability in turn through a huge statistical sample. Under these circumstances brain control is distributed, working in consensus but with no specific precalculated solutions. This kind of system is adaptive and flexible, constantly configuring itself to match the actual input. Although this process has neither classification nor generalization rules, it acts as though such rules were present. Learning itself results in a modified but more durable coupling density and a reconfiguration of the neural network, called brain plasticity, a kind of self-organization. The interaction of the brain with its environment, together with the existing genetic information leads to the formation of new information. It is thus possible to say that the brain reprograms itself, creating thereby the very foundation for memory, learning and creative thinking. Supporters of the PDP model often say: ‘There is no hardware and no software, there are only connections.’

Generally, human information processing is dynamic, interactive and self-organizing as well as superior in optimization and adaptation, a non- serial task. Also, it is robust and not too sensitive to inaccurate data; it handles incompleteness, ambiguity and false information very  well. More specifically, in PDP-model terms the basis for these good qualities is that knowledge is globally stored in the existing network or structure and is continuously available. Essential information exists as frames or schemata, which are stored in flexible configurations offering the automatic supply of missing components, in a process of continual adaptation to meet the situation at hand.

Another key concept of the PDP-model is gentle degradation. PDP does not know a critical amount of neurons when the network stops working. All parts may be seen as redundant and a damaged brain has a diminishing capacity corresponding only to the area of injury.

A special theory concerning selective mechanisms in the brain has been presented by Gerald Edelman (1987). It is called neuronal group selection (NSG) and is founded on the notion that many brain processes operate by natural selection, a kind of neural Darwinism. Also, processes governing brain formation and growth are of the NSG type. In the developing brain, specialization of cell function is determined by the characteristics of the other surrounding cells in which it finds itself. Cells of a developing nervous system tend to migrate to brain areas favourable for their further specialization. The selection unit is a number of neurons called the neural group, more or less specialized to respond to a certain pattern of input. Different groups may have the same input pattern but their reaction will differ a little according to internal structure and relation to other groups. Some groups are strongly specialized to react in a defined way to a certain input and are said to have repertoires. Primary repertoires become established shortly after birth and do not change. Secondary repertoires are established by change of connection strength between and among primary repertoires due to the situation at hand and are therefore in a constant flux.

Stable repertoires emerge by reorganization of old neural groups from other, less stable repertoires, and result in something new and more appropriate. In this reorganization a constant competition takes place between the groups resulting in a growing repertoire and stronger inter group connections.

Besides the PDP-brain model, several others are well-known. Especially relevant here is the triune concept of the brain presented by Paul MacLean in 1972. According to this theory, the brain is organized in three main hierarchical layers, arranged with the oldest in the centre surrounded by the others, like the skins of an onion. The human brain is a complicated web of these layers superimposed on to each other according to the different evolutionary stages. It is reminiscent of a thousand-year-old town where old and new buildings exist side by side. Each of us thus carries the history of the whole biological evolution in our nervous system. The three main stages are presented in Figure 5.1.

Figure 5.1 The triune concept of the brain.

The oldest layer, the instinct layer, is also called the reptilian brain and provides basic reflexes and instinctive responses. It can be characterized by aggression, rituality, territoriality and social hierarchy. The next layer, the emotional layer or the limbic brain, is the location of feelings and the important drive for altruistic behaviour such as the care of offspring. The third layer, the thinking layer or the neocortex brain, is capable of manipulating abstract symbols; it can analyze, associate, imagine and plan. Here is to be found the location of the essential human quality of intuition.

If the reptilian layer has a certain degree of consciousness, the limbic may be considered to be conscious and the neocortex wholly self- conscious. Unconsciousness and consciousness, old information and new thus exist side by side in a development similar to that of the city. The general function of these layers may be summarized thus: reptilian as biological, limbic as emotional, neocortex as intellectual. The co- ordination of all three layers defines what can be described as the human mentality.

A simplified anatomical drawing showing the three layers  is shown in Figure 5.2.

“The reptilian brain stands for the figures and roles which underlie all literatures. The limbic system brings emotional preferences, selection and development of the scenarios into play. And the neocortex, finally, produces on this substrate as many different poems, tales, novels and plays as there are authors” (Jantsch 1980).


Figure 5.2 Layers of the human brain.

Earlier we have stated that a prerequisite for consciousness is the existence of a memory. Apparently a memory residing in a conscious brain has no storage limitations. During a lifetime each  individual gathers a tremendous amount of knowledge and experience for their own benefit. With the development of basic aural and visual communication, this knowledge could be transferred to other individuals to a certain extent. With the advent of a language among higher animals, communication was suddenly raised to a superior level and both knowledge and skill began an exponential accumulation. The nature of language implies an overwhelming communication desire as a guiding motive for human life. For humans, an existence without communication with kinfolk is something unthinkable.

However, when self-conscious beings became aware of their own mortality they realized the problem of memory loss. The possessor of the memory sooner or later dies; its content is thereby lost. Another problem was the handling of the memory content: retrieval mechanisms were by no means on a par with the unlimited storage capability. An example of how knowledge could be conserved and transferred to following generations is the traditional storyteller who is both a memory bank and a conveyor of its content. To preserve knowledge and to transfer it between different generations, the ancient storyteller acted both as a memory bank and a conveyor of its content.

The above-presented brain models are mainly of a structural nature. One of the interesting functional models, the brain resource model introduced by Matti Bergstrom (1991) is based on a theory concerning the attitude of humans towards their the own brain. It is not possible to apply the same view on the brain as we do upon other human organs, such as the stomach, the liver, etc. The brain is the only part of the human organism which studies itself and this implies inevitable consequences for inherent values. These values cannot be excluded when studying the brain; without their application in human morality and ethics there are no qualities which may be called human. Furthermore, our values, coupled with feelings and fantasies, are necessary for the development of a healthy personality. The brain resource model does not discriminate between values and knowledge, between subject and object.

The growth of the brain is considered to be dependent upon an adaptation to an ever-more complex and demanding environment. A homogenous environment with no sudden changes permits survival with a small brain and an uncomplicated nervous system. The transformation of the planet, with shrinking oceans, formation of new land, severe weather changes, natural disasters, etc. demanded something more. Survival during these circumstances had to be built upon an improved capacity to receive, store and handle information, mirroring a more complex environmental structure. With this perspective, the brain is simply seen as an interface between the environment and the internal world of the organism. Its purpose vis-à-vis the organism is similar to that of the skin: to adapt to and protect from the environment.

The brain-resource theory takes a very pragmatic view of the old mind/body problem. The mind embraces not only the abstract world belonging to areas like psychology, sociology or philosophy, but concrete physiological nerve processes as well. The ‘wholeness’ of the system is the mind and the different physical parts of the body. This view is exemplified by thermodynamic concepts: pressure, volume and temperature — macroscopic entities describing the wholeness of a system, but which are not possible to locate anywhere in a gas. The same goes for the mind, which it is not possible to pinpoint at a certain place in the brain.

In so far as the thermodynamic view has made possible both a demystification and a reasonable explanation of the complex concept of mind, it has been adopted into neurodynamics. Complex nerve systems with astronomical quantities of simultaneously propagating signals are not possible to analyze in terms of single pulses; the only way to understand such a mechanism is through a statistical approach.

One of the most significant qualities of the brain is its value function. This may be defined as the capability to choose and arrange knowledge according to an internal scale. Information and knowledge have no value of their own but are assigned a value as they become ordered and sorted. To assign values is to control and process information and to create negentropy, the opposite of entropy. Information overload, a serious problem in our current society, can never be handled with more information; a value should be designated to that which exists.  To choose, evaluate and see a wholeness is the very core function of the human mind. A value-free science, for example in the nuclear area, is something of a paradox, when generating sophisticated knowledge to be used in an arms race and to promote chaos and potential destruction of the whole world.

A defective value function is always more critical than the quality of the adopted values. Children often reject a school culture overloaded with value-free knowledge which is so apparently without meaning for themselves; they turn instead to the hard gang morality and simple reward system of the street.

Another significant resource of the brain is its creativity function. The origin of creativity is found in the chaotic signal pattern of the brain stem, which acts as a random generator for new ideas if not restrained by social constraints. Some of these ideas may reach and influence the ordered levels of the brain, the neocortex, where a sudden change of mind occurs and is experienced. This mechanism may be functionally illustrated by catastrophe theory as a sudden and abrupt change when new ideas are born.

Our contemporary Western society does not support creativity. General social standardization, passivism and information pressure all too often restrain activity, spontaneity and the important work of the brain’s random generator. The striving for a successful planning of our future also delimits creativity. To accept creativity is to lose the possibility of planning even the not-too-distant future. While creativity implies new and unpredictable knowledge which can lead to an unpredictable world, it also offers a strong survival value for adaptation to the future. Finally, creativity demonstrates how disorder and chaos are prerequisites of order and harmony.

A further consequence of the brain-stem as a chaos generator is the general human fear of the unknown. The unknown internal ego and the unknown external unbounded world have slowly been mastered by the strategy of art and knowledge. Figure 5.3 shows how these concepts counteract the fear of the unknown in the human milieu. Another key concept included in the theory is the potentiality of the brain. This term indicates that if one of the existing possibilities is realized by action, the others disintegrate. The responsibility inherent in each action is therefore tremendous; other worlds which are possible are destroyed when a choice is made. This dilemma has traditionally been solved in the Eastern countries introspectively, by decreasing external actions and increasing the internal potentiality of the brain. Could fewer actions instead of more be a more effective way to tackle this dilemma in the Western world as well?

Figure 5.3 Art and knowledge counteracting human fear (from Bergstrom 1991).

The two competing states, the random and chaotic associated with the brain-stem, and the fixed and ordered linked to the cortex, are the two bipolar extremes of the brain. The simultaneous existence of chaos and order in complex, dynamic systems, however, tends to organize the content in a middle way in some kind of dissipative structure. It seems reasonable that such structures are generated in a self-organizing process of the brain, creating a new and relatively stable order. A large amount of dispersed information is suddenly joined to an integrated whole — a new idea, paradigm or method is born.

The brain hologram metaphor has been suggested by a number of scientists, including Carl Pribram (1969). A hologram (from the Greek holos, whole) is a kind of photographic image, created by illumination of a laser beam and has the following properties.

  • The image is three-dimensional; it may be viewed from many aspects.
  • A part of the hologram may be used to reproduce the whole image. The resolution of the whole image decreases as the area of the part decreases.
  • Images can be superimposed and also individually recovered.

The holographic effect is the result of an interference pattern. To explain this phenomenon, let us take the analogy of three stones dropped in a pond of water. The resulting three circular wave systems produce an interference pattern as shown in Figure 5.4.

The pattern holds all information concerning the position of the dropped stones. A fragment of the pattern is sufficient to reconstruct the whole wave system (see Figure 5.5).

A holographic photograph is created by use of a laser light split into two beams. One beam shines directly on the film while the other is reflected from the object to be photographed. Unlike ordinary photographs, the result is a blur covering the whole negative. This blur is a kind of interference pattern and when a laser beam is projected through the negative, the object reappears at a certain distance away from it. Different parts of the object are brought into focus by changing the viewing position (see Figure 5.6).

Figure 5.6  Holographic photography

If images from a number of objects are stored, reflections from each item act as references for the others. Thus, one object may be used to recall another — a kind of associative memory.

An examination of the area of the human brain concerned with vision shows that it possesses holographic qualities. When a piece is cut away, nothing specific is lost from the field of vision. What happens is that the wholeness is seen less distinctly. The ability to see whole scenes without decomposing them into features, or to filter out special items from a homogeneous background are also holographic attributes. To discern a particular face in a crowd of people or to recognize a certain voice among all other vociferous voices in a cocktail party are typical examples.

A neural hologram may be imagined as a propagation of waves of dynamic neural activity. It should be obtained as a result of interference of neurons between two patterns. One sent directly acting on the near end of dendrites and one slightly delayed acting on the far end of dendrites. The input information is thus both distributed and redundant by the property of mutual convergence and divergence in neural pathways.

Of course, there is no sign of a complete correspondence between the real hologram and its neural equivalent. As an explanatory theory, though, it may shed light on certain processes of the working brain.

Source: Skyttner Lars (2006), General Systems Theory: Problems, Perspectives, Practice, Wspc, 2nd Edition.

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