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by Alessandro E.P. Villa
The possible strategies that we could use in trying to comprehend cerebral functioning hinges on the subsequent problems arising from interdisciplinary studies of molecular, cellular, individual and social behavior. Many disciplines have an interest, and an important contribution to make, in obtaining an acceptable solution: philosophy, psychology, neuroscience, pharmacology, physics, Artificial Intelligence, engineering, computer science and mathematics. Whilst such interdisciplinarity makes the problem more exciting it also makes it more difficult. The languages of various scientific disciplines have to be used, and appeals to the knowledge bases in those disciplines also made. Scientific thought as we know it today, is based upon the assumption of an objective, external world. This conviction is supported by a rationale which calls upon mechanical laws of causal efficacy and determinism. Fundamentally, it is the correspondence between the hypotheses and their predictions through experimental research that builds the empirical success of Science, as we know from the cultural heritage of Galileo Galilei.
One of the most striking characteristic of the organization of the nervous system is its direction towards temporal information processing, illustrated by the phenomena of memory and futural projection which are necessary components of consciousness and of the so called higher nervous activities. It is interesting to this respect to note that throughout the Middle Age until the end of XVIth century the prevailing brain theory was the theory of localization of the faculties into three cerebral cells (from its latin name cellae and not referred to the modern meaning of cell). The first cell, the most anterior one, contained the common sense (sensus comunis) recipient of all sensory modalities and fantasy (fantasia). The second cell was lying between the first and the third cells and contained the imagination (imaginativa) and the cognition (cognitiva). The third cell was located in the most posterior part of the brain, but it was functionally intended as the most distant cell with respect to the sensory inputs, and contained memory (memorativa) and according to some authors a part of cognitive faculty associated to the estimation (estimativa). Besides the dissection of corpses very little, if any, invasive investigation of the brain was available until the XIXth century, and those concepts remained alive among the scientific community until nowadays.
The biological laws of neuroscience developed in the XIXth and XXth century, as well as the construction of mathematical axioms were derived from observations and pertaining to a priori knowledge. If however, the observation is exclusively and stringently applied to the description, the observation becomes reductive. Since the application of scientific protocols to the investigation of how the brain works it appeared that the dynamic relations between memory and sensorimotor activity could reveal abrupt reorganizations of information, characterized by a temporal dimension other than the one attributed by the slant of classical mechanisms. As queried by the mathematician Hadamard about his own mental experience Einstein replied that the words and the language, written or spoken, did not seem to play the least role in the mechanism of his thoughts. The psychic entities which serve as elements of thoughts are symbolic images more or less decipherable, which can be reproduced or combined willingly. This process evolves necessarily from the rupture of the temporal constraint, and appears similar to the aesthetic approach as a method of recognition. A single quantitative measurement becomes unable to determine an axis of congruity and paradigms other than the classical ones should be considered for a scientific interpretation of the results, following a process likewise the introduction of the superstring theory with respect to the standard model.
The information processing effected by the brain appears then as a result of an accordance between Nature (“bottom-up”) and Nurture (“top-down”). Research strategy based on the “bottom-up” information flow, the preferred view by neurobiologists, seems potentially necessary and sufficient; however it is not wholly viable to actual experimentation considering the impossibility of simultaneously examining, even in a primitive species, all cellular elements of the brain and all variables that affect those elements. The “top-down” strategy with the assistance of “dark boxes” is easier to bring to fulfillment but insufficient and irrelevant in understanding the mechanisms coordinating the local networks of cellular elements. It seems therefore that a fusion of the “bottom-up” and “top-down” mechanisms is needed, leading to a distinct approach to the Neurosciences. Let us call it Neuro-Heuristics, or Neuristics, issued from the Greek terms neuron (nerve) and heuriskein (to find, to discover). Its definition corresponds to that branch of Science aimed at exploring the assumptions of the Neurosciences through an ongoing process continuously renewed at each successive step of the advancement towards understanding the brain in its entirety.
In this framework, the “result” cannot be simply positive or negative because the process itself cannot be reduced to proficiency as such. The accent here is on the dynamic and no reducible characteristic of this approach. It is important at this point to make a distinction from Bergson’s psychophysical interactionism. In Bergson’s perspective the transition to a successive stage is dependent upon the vital impulse which appears at each stage. Therefore, it is the vital impulse which is the activating agent of transition between the stages. In our perspective, the change occurs when an essentially new and unexpected combination develops from the preexisting properties. At the dawn of the XXIst century, such an approach can reap benefits from the new sciences and technologies which promote the emergence of new concepts; molecular biological studies and computer science can be an integral and crucial extension to the field of Neuroscience.
The emergent process of Neuro-Heuristics is accompanied by a perceptive jump (Gestalt switch). The analogy between the abstract levels of organisation in the computer and the brain encompasses the fundamental observation that computer programming represents a deliberate mock-up or artificial imitation of human intellectual activity. In reviewing hypotheses which are destined to be out of date, the neuro-heuristic perspective differs from the greater portion of cognitive studies. The Neurosciences have made only a minor contribution to the knowledge of the biological substrates of creativeness despite progress made in comprehension of the neurobiological basis of perception, training and memory by animal experimentation. The cognitive sciences however, faced the problem originated in the brain to separate declarative knowledge (“know what”) from procedural knowledge (“know how”). In this respect, it is undeniable that the cognitive sciences have benefited from its interchange with the field of artificial intelligence. In our view, intellectual activity cannot be reduced to its computational dimension. We subscribe to the synergy of information processing and Neurosciences. Such kind of synergistic process is not peculiar of our times and it follows several fundamental historical facts.
In 1753-1755 the Bernese physiologist Albrecht von Haller (1708-1777) published an essay, the “Dissertation on the Irritable and Sensitive Parts of Animals” (original title: De partium corporis humani sensibilius et irritabilus). This work was based on numerous experiments of vivisection and on stimulation of organs using the new knowledge offered to physiology by physics, chemistry and natural history. With a rudimentary technique of stimulation, Von Haller classified the parts in irritable, sensible or elastic and noted that the reactions varied between different parts of the brain. The historical importance of the work by Von Haller is not so much related to the results obtained, but rather in systematically applying the new technologies with a scientific protocol. This approach resulted in a turnabout in the university environment of the XVIIIth century. With the introduction of currents of Galvanic fluids into the brain, a powerful new tool of investigation developed at the end of the XVIIIth and beginning of the XIXth century. The use of electricity was not strictly limited to its instrumental character, which was at the basis of electrophysiology, but rather the proper characteristics of propagation and generation of this type of energy became the basis of fertile hypotheses. Inspired by Von Haller and by the works of his compatriot Malacarne, Luigi Rolando, the Piedmontese physician added a fundamental contribution to the succession of the naturalistic descriptive paradigm which was adopted thus far. Supported by the work of Alessandro Volta, Rolando was struck by the analogy between electric devices and the structure of cerebellum to which he assigned a role in locomotion. In addition, Rolando was able to discern regularities in the morphology of the cerebral cortex and could establish relations between its parts while tracing the map and assigning them a name. Rolando’s research was based on the metaphysical assumption that brain organisation had necessarily to be submissive to constant and recognizable laws. His criticisms directed against the organology concepts of Gall, then diffused throughout the Occidental world, were not at all dictated by a priori concepts. Rolando did not underestimate these anatomical studies, but he denounced on several occasions the absence of objective evidence for distinct organs to the tens of mental functions identified by the phrenologists.
Plotinus (204-270), the great philosopher and founder of the Neo-Platonism, developed a unique theory of sense-perception and knowledge, based on the idea that the mind plays an active role in shaping or ordering the objects of its perception, rather than passively receiving the data of sense experience. In this sense, Plotinus may be said to have anticipated the phenomenological theories of XIXth and XXth century. However, the heuristic paradigm of Von Haller-Rolando did not develop further in the neuroscientifics of the XIXth century, which possibly explains the conceptual delay taken by biomedical research in Neurosciences with regard to Mathematics and to Physics and Chemistry. In the Forties of the XXth century the confrontation between the Neurosciences and the Theory of Communication by Shannon and Weaver led to the emergence of the cybernetic movement. There is an analogy between what occurred two hundred years ago with the initiation of electricity and technology and the situation of today in which the Neurosciences are confronted with Computer and Information Sciences. In the Enneads Plotinus states that the knowledge of the One is achieved through the experience of its ’power’ (dynamis) and its nature, which is to provide a ’foundation’ (arkhe) and location (topos) for all existents. In the neuro-heuristic paradigm the term One could be replaced by Complexity and experience replaced by scientifically testable hypotheses. The confrontation between Neurosciences and Computer and Information Sciences will allow the emergence of new provisional hypotheses, i.e. functional hypotheses limited to the topos where these hypotheses evolved, for an ongoing “stepwise” understanding of the higher cognitive functions.
To use a metaphor, we could state that the neuro-heuristic approach observes the experimental results beyond the surrounding wall of the hypothesis by coupled conjecture and testing, similarly to a child playing in a garden while observing what happens beyond the enclosure, which could be a hedge, a gate or a lattice. All of these are closures but they are all different and belong to distinct topoi. This metaphor also serves to indicate the character, sometime with passion, sometimes with pleasure that must clothe the act of the scientific discovery. In order to retract the former maxim ludendo docere, research directed strictly by a registered finality according to a settled perspective is dangerous for scientific creativity. Remarked upon by the neurobiologist, Alan Hodgkin: “The stated object of a piece of research often agrees more closely with the reason for continuing or finishing the work than it does with the idea which led to the original experiments. In writing papers authors are encouraged to be logical, and, even if wished to admit that some experiment that turned out in a logical way was done for a perfectly dotty reason, they would not be encouraged to “clutter up” the literature with irrelevant personal reminiscences”.
Since the Neolithic times that the first flint was produced, the tools have altered in form, but the interaction that they have with the pathway of discovery has remained essentially constant. Due to modern computer technologies, investigation methods without precedent have emerged in research of the Neurosciences. However, the complexity of problems presented to the researcher of today is of such a broad span that the database approach is unable of reducing its computational performance to a disciplinary dimension. The neuro-heuristic approach to brain sciences attempts to promote a paradigm based upon synergy between Modelling and Experiments which parallels the synergy between Computer and Information Sciences with the Neurosciences.
The hard sciences of engineering, physics and mathematics are now making important contributions to a theoretical framework for the various micro and ever more global information strategies used in the brain. Non-invasive brain imaging, lesion studies and single and multi-electrode studies on animals and humans are now producing results of deep import as to the networks of neural modules supporting a broad range of psychological tasks. The increasing information about these networks is raising optimism as to the possibility of constructing a global model of the brain as a multi-modular system. The philosophy behind such an approach is to start with simple neurons and modules, and develop increasing complexity in due course. The task itself requires transdisciplinarity and the neuroheuristic approach may lead to a framework from which to tackle the study of higher nervous activities from a global viewpoint.
Alessandro E.P. Villa, November 2001
Professor of Biophysics and Neuroscience
Faculty of Medicine
University Joseph Fourier - GRENOBLE 1
Laboratory of Neurobiophysics
INSERM U 318 - CHUG Michallon
Pavillon B - BP 217
F-38043 GRENOBLE CEDEX 9
This text is licensed under a Creative Commons Attribution-ShareAlike 3.0 Unported License.