Neuronal Group Selection Research Articles

Temporal Mechanisms In Perception

The temporal mechanisms underlying perceptual, motor, and cognitive processes have some philosophical and aesthetic implications. This chapter describes the primary consciousness, system states in the 30-msec domain, presemantic temporal integration in the 3-second domain, and philosophic and aesthetic implications. Primary consciousness is characterized by three components. The first component emerges as a result of the evolution of close linkages between systems mediating concept formation in various areas and interoceptively determined value systems mediated by circuits related to hedonic responses. The second component is a separate form of memory emerging as a result of the functioning of these linkages, while the third component provides the sufficient condition for consciousness to appear. Consistent with the ideas of neuronal group selection, the model discussed in the chapter proposes that special circuits have evolved that carry out a continual re-entrant signaling between the second component and the ongoing real-time exteroceptive global mappings that are concerned with the perceptual categorization of current exteroceptive stimuli before they can form part of the value-category memory.

Formal minds and biological brains: AI and Edelman's extended theory of neuronal group selection

The author explores Gerald Edelman's work (G.M. Edelman, 1987; 1988; 1989; 1992) against the background of pertinent problems in artificial intelligence (AI): the traditional symbol manipulation paradigm, and other well-known developments such as Soar, the so-called new AI, connectionism, and genetic algorithms. Intelligence and symbol manipulation, Edelman's neural group selection theory, its extension, and their relation to AI are discussed.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

A neuronal group theory of sleep function.

A new theory of sleep function is presented within the context of the neuronal group selection hypothesis, which emphasizes that neuronal groups compete for neurons via use-dependent synaptic formation and atrophy. It is hypothesized that sleep serves to stabilize these competitive processes by providing a pattern of stimulation that serves to maintain a synaptic infrastructure upon which wakefulness-driven synaptic changes are superimposed. Sleep is 'quantal' in nature in that sleep is a statistical property of a population of neuronal groups in different states. The theory unifies past theories of sleep function yet simultaneously provides a fundamental new paradigm for sleep research.

Behaviorally based modeling and computational approaches to neuroscience.

The almost incredible advances that have recently occurred in the power of computers available to scientists in all disciplines have encouraged an explosion of neural network and behavioral models. Some of these have been constrained more by the imagination of the programmer than by rude biological facts. Their relevance for the experimental neuroscientist thus varies from case to case. Some models (e.g. Grillner's model of lamprey swimming movements) are so closely based on known neuroanatomy and neurophysiology that it becomes possible to generate and test precise experimental predictions. Other models (such as MURPHY and NOMAD) use neurobiological principles in their architectures, but do not portray any particular organism. Although it is harder to relate the study of these models of the study of real animals, they fulfill an important explanatory role. They make possible insights into how behavior is controlled by neuronal activity that would be unobtainable in real animals using present methods. Thus, even the excesses of neural modeling have provided a useful impetus to what is undoubtedly a most promising approach to integrating data from the various disciplines concerned with behavior and the mind. The problems have been pointed out by many authors (see citations in our introduction), and a phase of more critical evaluation appears to have begun. We hope that our brief survey of models based on widely different theoretical approaches, but all aimed at explaining behavior, will encourage critical comparisons to be made. As in more mature fields, such as thermodynamics, we can expect that more complete models will force an evaluation of theoretical hypotheses against the entire body of available evidence, rather than just a few pertinent test cases. Such evaluation will make possible a much more rigorous exclusion of invalid or inconsistent theoretical ideas. From such studies, a much smaller, but more robust, set of basic principles can be expected to emerge. From the perspective afforded by our own modeling studies, it appears essential that modeling be informed by a general theory of brain function. In this work, the theory of neuronal group selection provides a useful basis for further work by virtue of its consistency with basic evolutionary and physiological principles and the power of the selection paradigm to shape neural networks in behaviorally adaptive directions.

Building a bridge between neurobiology and mental illness

GABA (γ amino butyric acid) is the most abundant and important inhibitory transmitter in mammalian CNS. It counterbalances the glutamate mediated neuronal excitation. Abnormalities of the interaction of these two transmitters might change the mechanisms of neuronal group selection that according to Edelman [ Neural Darwinism. Basic Books, New York] play a role in mediating several brain functions including cognition processes. Indeed imbalances in GABAergic functions were shown to elicit psychoses. They can be obtained by administration of drugs that affect synthesis, metabolism and uptake of GABA and thereby cause a persistent stimulation of GABA A receptors or perhaps by genetic abnormalities in DNA transcription, pre-mRNA splicing, mRNA translation and posttranslation modifications of GABA A receptor subunits. The complexities in the regulation of GABA A receptor subunit structure, synthesis, assembly and the brain location of specific mRNA encoding for these subunits are investigated with in situ mRMA hybridization specific for subunits of GABA A receptors. The role of the variability resulting from the complexities in the regulation of GABA A receptor allosteric modulation by drugs and putative endogenous allosteric modulators of GABA action at GABA A receptors is discussed. This discussion gives relevance to the possibility that genetic abnormalities in the expression of proteins participating in GABAergic function are to be considered as a possible target of the genetic defects operative in psychoses. In line with this thinking, it is suggested that partial allosteric modulators (partial agonists) of GABA A receptors and the phosphothioate of methylphosphonate analogs antisense to specific mRNA oligonucleotides that mediate the expression of genetic information concerning GABA A and glutamate receptor subunits may become valuable tools in psychiatric research. Perhaps in the future these studies might generate new ideas useful in the therapy of genetically determined psychiatric illness.

Synthetic neural modeling applied to a real-world artifact.

We describe the general design, operating principles, and performance of a neurally organized, multiply adaptive device (NOMAD) under control of a nervous system simulated in a computer. The complete system, Darwin IV, is the latest in a series of models based on the theory of neuronal group selection, which postulates that adaptive behavior is the result of selection in somatic time among synaptic populations. The simulated brain of Darwin IV includes visual and motor areas that are connected with NOMAD by telemetry. Under suitable conditions, Darwin IV can be trained to track a light moving in a random path. After such training, it can approach colored blocks and collect them to a home position. Following a series of contacts with such blocks, value signals received through a "snout" that senses conductivity allow it to sort these blocks on the basis of differences in color associated with differences in their conductivity. Darwin IV represents a new approach to synthetic neural modeling (SNM), a technique in which large-scale computer simulations are employed to analyze the interactions among the nervous system, the phenotype, and the environment of a designed organism as behavior develops. Darwin IV retains the advantages of SNM while avoiding the difficulties and pitfalls of attempting to simulate a rich environment in addition to a brain.

Structural and molecular plasticity in the dorsal horn: A genuine model for neuronal and synaptic group selection

Structural and molecular plasticity in the dorsal horn: A genuine model for neuronal and synaptic group selection

The Remembered Present: A Biological Theory of Consciousness

How does the brain know? Gerald M. Edelman, Nobel Prize—winning neuroscientist, presents his theory of global brain function and the neurobiology of consciousness.The Remembered Presentis the third in a trilogy beginning withNeural Darwinismin 1987, followed by Topobiology in 1988. These two books lay the groundwork for the present volume, presenting Edelman's theories of neuronal group selection and developmental neurobiology. The Remembered Presentbuilds on this framework, extending the theory to the issue of consciousness. Despite its relationship to the previous volumes,The Remembered Presentcan be appreciated and understood by itself. The author does restate the basic tenets of his theories of neuroanatomy, neurophysiology, and morphogenesis as they relate to his theory of global brain function and the neurobiology of consciousness. Referral to the previous volumes is necessary for further understanding of the experimental evidence on which the theories are based. The author divides his book

Brain plasticity as a basis for recovery of function in humans

One of the factors leading to the virtual neglect of the long-term potential for functional recovery following brain damage was the eclipse of plasticity concepts during the 100 years following Broca's 1861 publication on location of function. However, in the last 30 years evidence has been accumulating that demonstrates the plasticity of the brain and thus recovery potential is a subject of practical as well as theoretical interest. “Unmasking” of relatively inactive pathways, the taking over of functional representation by undamaged brain tissue, and neuronal group selection are among the mechanisms that are being explored. Human models of recovery of function include hemispherectomy patients that have regained bilateral function, facial paralysis patients who recover function (with appropriate rehabilitation) after VII–XII cranial nerve anastomosis, and patients with muscle transpositions to re-establish lost motor functions. The role of early and late rehabilitation, with attention to psychosocial and environmental factors, appears to be critical for recovery.

Synthetic neural modeling: the 'Darwin' series of recognition automata

The authors describe how the theory of neuronal group selection (TNGS) can form the basis for an approach to computer modeling of the nervous system. Three examples of synthetic neural modeling are discussed. Darwin I was designed to examine the process of pattern recognition and some general factors relating to degeneracy and amplification in selective systems. Darwin II introduced recognition units with some of the properties of neuronal groups, connected in reentrant networks to permit exploration of aspects of the recognition process leading to categorization, generalization, and associative memory. Darwin III is a behaving automation whose behavior is not programmed but results from its encounter with events in its world under constraints of neuronal and synaptic selection. The oculomotor, reaching, touch, and categorization subsystems of the Darwin-III system are discussed. Darwin III is compared to models based on neurobiology, models based on artificial intelligence, and connectionist models.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Reentrant signaling among simulated neuronal groups leads to coherency in their oscillatory activity.

Recent experiments have revealed tightly synchronized oscillatory discharges in local assemblies of cortical neurons as well as phase coherency of oscillations at distant cortical sites. These findings are consistent with the theory of neuronal group selection, a population theory of brain function that is based on the properties of local groups of neurons. A set of computer simulations shows that cooperative interactions within and among neuronal groups can generate the observed phenomena. In the simulations, oscillations within neuronal groups are generated through local excitatory and inhibitory interactions. Different groups in general oscillate in an uncorrelated fashion. Coherency of the oscillatory activity of different neuronal groups depends crucially on reciprocal reentrant signaling and can reflect the spatial continuity of a stimulus. Separated or discontinuous features of a given stimulus can be transiently associated in a temporally coherent pattern through reentrant signaling between groups in networks responding to different aspects of that stimulus. A simulation of reentrant activity between arrays of neuronal groups selective for oriented lines and pattern motion displays cross-correlations between groups that are responsive to different parts of a stimulus contour if these parts move together. Such coherency among neuronal groups might be used in the discrimination of a stimulus from other stationary or differentially moving elements in a visual scene.

DARWINIAN SELECTION IN THE BRAIN

In this book, Gerald Edelman explains how process akin to natural selection, but one which operates in somatic time on the interactions between neurons, is responsible for order in the brain. The theory of neuronal group selection was proposed by Edelman over ten years ago and has since been developed by Edelman and his colleagues at Rockefeller University, Leif Finkel and George Reeke, into well-posed and synthetic theory of nervous-system development. In this review, I will focus on the issues of most concern to evolutionary biologists: in what sense is the brain selective system, and what are the similarities and differences between neuronal group selection and the genetical theory of evolution. There are two basic aspects to any selective system: variation in and heritability. Consider first variation in fitness. In genetic evolution, the word fitness is used in least two different senses: the first in an operational sense and the second in design or engineering sense. There are several measures of operational fitness, including the per capita rate of increase (first used by Fisher [1930]) and expected reproductive success. Fitness in the sense of better design (often referred to as adaptedness) is far more difficult to define in genetic evolution, and there is no universal definition, since it depends on the specifics of the species and its environment. In neuronal group selection, fitness is also used in the operational and engineering senses as discussed shortly. What sort of entities possess fitness? Again, this depends upon the problem of interest, but candidates in genetic evolution include bits of DNA, genes, chromosomes, organisms, populations, and possibly whole species. A final point to realize about in evolution is that it is always dependent on the environment. What is fit in one environment may be unfit in another. In neurobiology, candidates for units of selection are the synapse, neuron, neuronal group, nuclei, and whole cortical columns. It is basic to the theory of neuronal group selection that groups of neurons function as units of selection. A neuronal group is defined as a set of more or less tightly connected cells that fire predominantly together (p. 198). With terms appropriately translated, this definition of group corresponds nicely to the definitions of group structure used in population genetics (see, for example, Uyenoyama and Feldman [1980]). In neuronal group selection, also has an operational and design sense, referring either to

Book Reviews

Books review in this article: Glial Cell Receptors edited by H. K. Kimelberg Pineal Research Reviews, Volume 6, edited by Russel J. Reiter Neural Darwinism: The Theory of Neuronal Group Selection by G. M. Edelman Receptor Biochemistry and Methodology, edited by J. C. Venter and L. C. Harrison Volume 8: Dopamine Receptors, edited by I. Creese and C. M. Fraser Volume 9: Structure and Physiology of the Slow Inward Calcium Channel, edited by J. C. Venter and D. Triggle The Alpha‐1 Adrenergic Receptors edited by R. R. Ruffolo

Interactions among affect, cognition, and visuomotor coordination as measured in words and symbols.

The associative frequencies of responses to stimulus words during free and controlled forced-choice word-association tests correlate well with each other and with assessments of the affective character (emotional content) of the stimulus words for the test subjects (Osgood Index) for three samples of volunteer French undergraduate students (ns = 200, 64, and 72). These indices correlate negatively with the subjects' performance on Digit Symbol Substitution tests. Neisser's theory of schemata and Edelman's theory of neuronal group selection may provide insight into this relationship. If the associative frequency of a subject's response decreased, the affective content of the word stimulus (as perceived by the subject) diminished as well. This relationship was associated with a relatively higher score on Digit Symbol Substitution. Conversely, it was observed that subjects whose responses were characterized by high associative frequencies (whether the response was spontaneous or forced-choice) rated the stimulus words as having a relatively stronger affective content or emotional character and performed less well on Digit Symbol Substitution.

Neural Edelmanism

The recent book Neural Darwinism (ND) by Gerald Edelman, claims to put forward ‘a radically new view of the function of the brain and nervous system’. Its main focus is on the understanding of the biological basis of perception. This new view is based on what Edelman calls 'The Theory of Neuronal Group Selection', the subtitle of his book. In spite of Edelman's lengthy and spirited account of this new theory, most readers appear to have had some difficulty in grasping his ideas and many have complained that the book is not easy to read. It has been particularly difficult to relate Edelman's ideas to those already current and well-known, especially as Edelman himself says rather little on this topic. In this critique I aim to set out Edelman's central ideas, as they appear to me, in a clearer and more digestible form. I examine both his general exposition of these ideas and the simulations he has presented to support them, giving page references so that the concerned reader can check my statements against the text. I have considered also Edelman's original papers, upon which the book is based, but I have not considered more recent papers which deal with matters (such as Darwin III) that are not covered in the book.

SURVIVAL OF THE SYNAPSES

NEURAL DARWINISM The Theory of Neuronal Group Selection by Gerald M. EdelmanTHE INVENTION OF MEMORY A New View of the Brain by Israel Rosenfield

A New Theory of Brain FunctionNeural Darwinism. The Theory of Neuronal Group Selection. Gerald M. Edelman

Previous articleNext article No AccessNew Biological BooksA New Theory of Brain Function Neural Darwinism. The Theory of Neuronal Group Selection. Gerald M. Edelman Dale PurvesDale Purves Search for more articles by this author PDFPDF PLUS Add to favoritesDownload CitationTrack CitationsPermissionsReprints Share onFacebookTwitterLinkedInRedditEmail SectionsMoreDetailsFiguresReferencesCited by The Quarterly Review of Biology Volume 63, Number 2Jun., 1988 Published in association with Stony Brook University Article DOIhttps://doi.org/10.1086/415843 Citations: 2Citations are reported from Crossref Copyright 1988 Stony Brook Foundation, Inc.PDF download Crossref reports the following articles citing this article:Justin Garson What Biological Functions Are and Why They Matter, 3 (Jan 2019).https://doi.org/10.1017/9781108560764Justin Garson Function, selection, and construction in the brain, Synthese 189, no.33 (May 2012): 451–481.https://doi.org/10.1007/s11229-012-0122-y

Plasticity in the organization of adult cerebral cortical maps: a computer simulation based on neuronal group selection

Recent experimental evidence from the somatosensory, auditory, and visual systems documents the existence of functional plasticity in topographic map organization in adult animals. This evidence suggests that an ongoing competitive organizing process controls the locations of map borders and the receptive field properties of neurons. A computer model based on the process of neuronal group selection has been constructed that accounts for reported results on map plasticity in somatosensory cortex. The simulations construct a network of locally connected excitatory and inhibitory cells that receives topographic projections from 2 receptor sheets corresponding to the glabrous and dorsal surfaces of the hand (a typical simulation involves approximately 1500 cells, 70,000 intrinsic and 100,000 extrinsic connections). Both intrinsic and extrinsic connections undergo activity-dependent modifications according to a synaptic rule based on heterosynaptic interactions. Repeated stimulation of the receptor sheet resulted in the formation of neuronal groups-local sets of strongly interconnected neurons in the network. Cells in most groups were found to have similar receptive fields: they were exclusively glabrous or dorsal despite equal numbers of anatomical connections from both surfaces. The sharpness of map borders was due to the sharpness of the underlying group structure; shifts in the locations of these borders resulted from competition between groups. Following perturbations of the input, the network underwent changes similar to those observed experimentally in monkey somatosensory cortex. Repeated local tapping on the receptor sheet resulted in a large increase in the magnification factor of the stimulated region. Transection of the connections from a glabrous region resulted in the organization of a new representation of corresponding dorsal region. The detailed simulations provide several insights into the mechanisms of such changes, as well as a series of predictions about cortical behavior for further experimental test.

Selective Neural Networks and Their Implications for Recognition Automata

Higher mental functions require the prior abitity to categorize objects and events according to sensory signals reaching the brain. The neuronal group selection theory postulates that this ability arises from a kind of Darwinian selection operating in somatic time on groups of interconnected neurons. These groups develop with varied and overlapping abilities to respond to patterns of input at their synapses. Groups that contribute to responses having adap tive value for the organism undergo modi fications in the efficacies of their synaptic connections that enhance their future re sponses to similar stimuli. Computer models of automata based on these prin ciples can carry out simple tasks involving recognition, categorization, generalization, and visual tracking. A general program for implementing such models is presented.

Neuronal group selection and the evolution of hominid cranial capacity

Postulates about excess neurons and the complexity of nerve-cell branching, while heuristic, have not closed the gap in explanation between intellectual capacity and properties of the hominid brain that are correlated with its size. The theory of neuronal group selection, and approach to brain action formulated only recently, suggests a partial solution to this outstanding problem. The theory generates neurobiologically potent and refutable models of higher psychological function that are expressed in terms of underlying neural mechanisms. When applied to hominid evolution it predicts specific linkages of cause and effect between selection for increased intellectual capacity and enlargements in brain size. The evolutionarily stable sizes of the tissue systems can be described, and are evaluated for simple cases. A new mechanistic model is obtained that links evolution in intellectual capacity with phylogenetic sequences of hominid cranial volumes.