Neural Group Selection Theory

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The theory of Neural Group Selection (Theory of Neural Group Selection) describes and explains the function of the brain for planning and carrying out actions on the basis of more recent findings in neuroscience . It was developed by the immunologist Gerald M. Edelman in the 1980s. What is new about this approach is that, on the one hand, memory cannot be viewed as a representative store of the content of what has been experienced, but as a dynamic system that is constantly changing during its activity. On the other hand, that consciousness is not to be understood as a state or activity localized in a certain brain region , but as the activity itself, in which all brain regions, even widely distributed regions, are in a constant reciprocal exchange of information.

Historical consideration

There is a long tradition of ideas and theories about human consciousness and memory . While this was initially a topic for philosophers, since the development of the natural sciences and their methods of studying humans and their brains , natural scientists have also dealt with this problem.

One approach of the considerations was to find out the special tasks of individual anatomically visible and possibly separate regions of the cerebrum . Such studies and findings on the anatomy of the brain became important, for example through the studies and publications (1909) of the German anatomist Korbinian Brodmann (1868–1918), who described the functions of the individual areas (areas) of the cerebral cortex . His works are of great importance to this day.

When, at the turn of the 20th century, the physiologist Charles Scott Sherrington (1857–1952) described decisive findings about the nervous system - its structure and its functioning - the function and functioning of the nervous system began to gain in importance for neurophysiology . That has continued and deepened to this day. In the course of time, the analysis (research) penetrated ever smaller structures of the nervous system and examined their function and their importance for memory and consciousness and, related to this, also for learning

With the studies of Eric Kandel (around 1976) on the sea snail Aplysia, in which he found that there is probably no central long-term memory in the brain, but rather the change in the synapses of the nerve cells involved , such as movements once performed, in the sense of easier and faster recovery - To support activation, the studies of behavior and movements had moved from the level of the neural centers to the study of individual nerve cells and their molecular changes.

This did not solve the memory problem described, but it showed the importance of the individual nerve cells , their synapses and the changes they make for the networking of nerve cells and groups of nerve cells.

The step taken by the immunologist Gerald M. Edelman, who had observed during the development of antibodies in the organism, that the organism did not, as previously assumed, genetically, was decisive for further development, especially for the type of interaction of all these individual elements given plans, but according to the evolutionary selection principle . The selection principle requires very large populations of similar but equivalent structures from which it can make a selection that is suitable for the individual case.

It was shown that the nervous system consists of populations of synapses on the individual nerve cells (thousands), populations of nerve cells (more than 10 billion) and populations of nerve cell networks (also billions) that meet these requirements. It can therefore be assumed that thoughts, actions and movements are developed and carried out according to this selection principle. Edelman has systematically checked and confirmed the consequences of this.

Theory

Development selection

While the genes determine the brain anatomy in the early embryonic development , there is already a high variability in connection patterns during the formation of the multiple branched nerve processes. At the same time “firing” neurons are preferentially connected to each other first in groups and these are connected to networks ( circuits ) ( somatic selection ). It comes to the formation of the primary repertoires (primary repertoires).

Experience selection

Through behavioral experiences that occur throughout life, synaptic selection then occurs . Groups are formed, the elements of which are similar, but not the same but equivalent ( degeneracy ). The more frequently used synaptic connections and thus their efficiency are strengthened in competitive selection processes. The synaptic connections and the efficiency of the less frequently chosen groups are weakened. A constant dynamic restructuring of the groups takes place through the adaptation to the current conditions. By selecting certain patterns from spatially distributed areas of what is perceived, categories can be formed that are necessary for assigning new impressions to what has already been experienced. As a result, the networks of the primary repertoires to secondary repertoires and maps are built up. The maps can be changed through selective use (e.g. the area of ​​the thumb in the motor cortex is enlarged by frequent text messages ).

Cortical Connections

An orderly cooperation with the result of a successful action / movement does not come about, as previously assumed, through the sequential processing in individual brain regions, but through the constant recursive exchange of signals in the entire cerebrum (see also telencephalon ). In the topological cerebral arrangement of the thalamocortical system, the thalamus is networked with the functionally specialized regions (the maps ) of the cortex in a diverse and recursive manner. Signal circles are formed in which there is a constant exchange of simultaneously transmitted signals between individual areas that are very distant from one another ( reentry ). As a result, the activities that take place in these areas are coordinated with one another in terms of time and space.

There is also a constant exchange of signals between this thalamocortical system and a second arrangement of the brain, in which parallel chains are run through in the same direction. These connect the cerebral cortex (cortex) with special subcortical structures such as the cerebellum (participation and synchronization of movements but also specific thinking skills), the basal ganglia (participation in the planning and implementation of complex motor and cognitive processes) and the hippocampus (main participation in the consolidation of content the short-term memory functions to long-term memory functions in the cerebral cortex).

Eventually, these constant activities are linked to nuclei in the brainstem and hypothalamus that activate neural plasticity - for example, synapse strength - within neural circuits and create adaptive responses. These influences are also referred to as rating systems. For the entire system, each use of the connections leads to changes in the neurons and their connections, so that the system is in constant adaptive change.

awareness

It is assumed that these reentrant processes make up consciousness . This is supported by the observation that in the case of actions that have already been carried out several times, in which the attention no longer needs to be directed to the individual aspects and parts of the execution, the activity of the signal exchange between the brain areas decreases, so that it is automated in the case of almost unconsciously occurring, so-called automated ones Actions is minimal. This ensures that when solving complex new and particularly cognitive tasks that require full attention, necessary other routine tasks (for example: writing, drinking coffee or driving a car) can be carried out at the same time without difficulty.

Addendum

The Theory of Neural Group Selection of Gerald Edelman sprang from theoretical considerations that Edelman had collected as an immunologist, due to its scientific experience and transferred to the brain structures of humans. At that time (around 1980) it could not be proven by scientific experiments and mathematical relationships.

However, the theory has partially found its way into other human science. It was used as the basis of learning processes in a work on operational learning theory .

The development of technical procedures for investigating brain activity - for example that of functional magnetic resonance ( fMRI ) have undergone various further developments since the turn of the millennium, so that the processes involved in the performance of the brain (motor and cognitive) can be observed in their action. That is why it is now generally recognized in the neurosciences that in all cognitive processes all parts of the brain are in constant communication with one another. This is also the subject of numerous studies and publications in the field of machine learning . In this respect, G. Edelman's considerations have proven to be realistic and forward-looking.

literature

  • Eric R. Kandel, James H. Schwartz, Thomas M. Jessel: Principles of Neural Science . 4th edition. McGraw-Hill Companies, New York 2000.
  • Eric R. Kandel: In Search of Memory . Siedlern Verlag, Munich 2007.
  • Gerald M. Edelman: Neural Darwinism, The Theory of Neural Group Selection . Basic Books, Inc, Publishers New York 1987.
  • Gerald M. Edelman: Divine Air, Destructive Fire . 2nd Edition. Piper Verlag, Munich 1995.
  • Gerald M. Edelman, Giulio Tononi: Brain and spirit, how consciousness arises from matter . CH Beck Verlag oHG, Munich 2002.
  • Jürgen Grzesik: Operative Learning Theory . Julius Klinkhardt Publishing House, Bad Heilbrunn 2002.
  • Karl Friston : The free-energy principle: a unified brain theory? in: Nature Reviews, Volume 11 (2010). Pp. 127-238.
  • Jürgen Grzesik; Operational learning theory , neurology and psychology of human development through self-change. Publishing house Julius Klinkhardt. Bad Heilbrunn. 2002.

Individual evidence

  1. ↑ Gerald M. Edelman Neural Darwinism, The Theory of Neural Group Selection . Basic Books, Inc, Publishers New York 1987
  2. ^ Brodmann K (1909). "Comparative localization theory of the cerebral cortex" (in German). Leipzig: Johann Ambrosius Barth.
  3. ↑ Eric R. Kandel, James H. Schwartz, Thomas M. Jessel. Principles of Neural Science 4th Edition 2000. McGraw-Hill Companies New York. Chapter 63 pp. 1247-1279.
  4. ↑ see also: also Eric R. Kandel. In search of memory . Siedlern Verlag Munich 2007, s. also Eric R. Kandel: In search of memory . Siedlern Verlag Munich 2007.
  5. ↑ Gerald M. Edelman. Neural Darwinism, The Theory of Neural Group Selection . Basic Books, Inc, Publishers New York 1987
  6. ↑ Gerald M. Edelman. Neural Darwinism, The Theory of Neural Group Selection . Basic Books, Inc, Publishers New York 1987, ISBN 978-0465049349
  7. ↑ Gerald M. Edelman, Giulio Tononi. Brain and mind, how consciousness arises from matter , CH Beck Verlag oHG. Munich 2002, p. 69
  8. ↑ Jürgen Grzesik; Operational learning theory , neurology and psychology of human development through self-change. Publishing house Julius Klinkhardtz. Bad Heilbrunn. 2002.
  9. ↑ for example: Karl Friston: The free-energy principle: a unified brain theory? In Nature Reviews, Volume 11 (2010) p. 133