Objectivism & anti-objectivism in cognitive neuroscience

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Action, attitudes et décision — Action, Attitudes and Decision.

Daniel Vanderveken and Denis Fisette. Copyright © 2008. 1

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Objectivism and Anti-objectivism in Cognitive Neuroscience

JEAN-LUC PETIT

1. A tension is now beginning to develop within a new sector of the neuroscience known as cognitive, that sector where psychology and physiology will soon have to attempt to find common ground in order to re-launch their science. This tension may not be at all obvious to the scientist but only to a philosopher who spends time in laboratories, who talks with researchers and who reads papers in scientific journals.

If one allows oneself to be taken in by the ever increasing mass of data without bothering to call in question linguistic habits, ideological references or familiar metaphors, it is quite easy to be convinced that a veritable “Laplacean Phrenology” will soon find itself in a position to respond to this naturally human intellectual ambition to localize, codify, circumscribe, establish links and hierarchies, encapsulate, predetermine, program, calculate, in a word — represent.

But if one pays attention to the ever increasing divergence between the same linguistic habits, ideological references and familiar metaphors, on the one hand, and the more empirically fertile intuitions, promising lines of research which are producing highly interesting results, on the other, one finishes up with quite a different impression. Instead of a General Cerebral Mechanics fulfilling, as anticipated, the aspirations of the philosophers of mind of the 1960s and 1970s with a procedure of computational representation, one is astonished to discover that it is the very dynamism of neurofunctional research which has become a disturbing theme, a theme which the instruments of logicoanalytical thinking applied to cognition are, in the final analysis, far less able to deal with than the kind of reflection developed in the phenomenological tradition, a tradition bearing upon the subjective conditions of the possibility of experience and of perceptual knowledge, the incarnation of these conditions in the body and their relativization in the pragmatic context of our inter-actions with other persons.

 

2. Today the media makes the most of concepts that have either been rejected or exploited by researchers and, by using them in a sense contrary to that intended by their authors, have managed to compose a quite fantastic picture of the brain as a universal hold-all. After the “pontifical neuron” evoked by Sherrington (1941) for critical purposes, we have been successively warned against the “grandmother neuron” (Lettvin 1991; Barlow 1982) the “yellow Volkswagen neuron” (Harris 1980), the “red light neuron” (Barlow 1985), etc. In spite of these warnings, data on neurons of something — locational, directional, facial neurons, mirror neurons and the like, designations which admittedly prepare the way for just such an abuse —, the press interprets these convenient, if misleading, descriptions without hesitation as proof of the existence inside the brain of representations or copies in miniature of each worldly object, whether physical or social. To be sure, this terminological elasticity offers re-searchers a margin of liberty that they much appreciate, all the more so since they doubt whether any kind of semantic regularization would be of much help. But they also lend themselves to spectacular short-cuts and ambiguous declarations which, for the purposes of communication, offer advantages over more controlled modes of description and classification. This is no doubt difficult to avoid in the practice of a science. But it pertains to the philosophy of science to warn the public against the fabrication of a myth. Not only can data which seems to justify an objectifying conception of the mind as a system of representation made possible by neurons which are designed for the task be interpreted differently, but one is obliged to resort to dynamic schema oriented towards action as the alternative solution.

 

3. Let us take a closer look at the scientific myth associated with the grandmother neuron. By definition, the stimuli of any sensorial system impinge on specialized receptors in the brain: for visual stimuli, for ex-ample, it’s the retina plus the optical conduction paths leading to the in-dividual cells of the primary retinotopic regions VI, each of which possesses its own retinal receptor field. But over and beyond the stimuli, what about the objects themselves? Does the possibility of separately identifying each object in the surrounding world require the hypothesis of a specialized neuronal detector?

A pattern of excitation not being an object, one jumps to the conclusion that what is true of the captors is also true at all other levels and one imagines that the complex sensorial information that this configuration transmits must finally converge upon a single cell individually responsi-ble for its perceptual interpretation (conceived as detection). All of which transforms the brain into an inventory of the physical world — unless of course one sets arbitrary limits to progress in empirical knowledge. Every external thing has to be represented locally by a cell whose activation is uniquely determined by the presence of this thing in the surrounding world. Problem: the destruction of this one cell should entail the withdrawal of the corresponding thing from the world. A parallel mythology formerly inspired those who were looking for a material equivalent of the body image, understood as a cartographic representation whose distortions conserve a certain somatotopic similarity with the physical body, making up a homunculus inscribed in the brain, a homunculus that was progressively duplicated until it ceased to possess any precise form. More recently this mythology can be seen in those who, by extrapolating from facts concerning inter-individual neuronal resonance, promise us a social neuroscience which would bring the representation of the Other down to just another representation.

One may well balk at what seems to be a phenomenological regression under the pressure of another tradition which only has one theory of representations: Locke reviewed and corrected by Turing. In any case, in all these instances what is at stake is the attempt to pack the essential dimensions of conscious experience into an anatomically localized structure, one which it is hoped will prove to be fixed and locally determinable. From a phenomenological point of view, our perception of this world depends upon a subjective power of identifying objects in the sur-rounding world. Our experience of the body rests upon the subjective activity of inhabiting a body and of intervening in the world. The very objectivity of this world is rooted in the intersubjectivity of our experience. The fact that the principal structures responsible for the meaning which this experience has for us do not float in a vacuum is not a reason for reducing them to representations in a mind-brain. This might seem like a pious philosophical vow. In truth however, and much more frequently than is generally thought, this is exactly what researchers in the neurosciences tend to do, just as soon as the development of their investigations leads them to reintroduce, into the description of the functioning of the brain, the structuring role of experience and the primacy of the activity of the organism against the naïve objectifications of a science which initially clothes its discoveries in ideological certainties

1 Neurobiological Foundations of the Perception of Individual Things

 “Face neurons”: this is the way one describes a group of cells belonging to the upper temporal fissure and which play a predominant role in the functional hierarchy of the treatment of visual information. These cells are so remarkably adapted to the recognition of facial features that one is tempted to see in them a proof of the unique cellular coding of the object of perception. The correlation between the neuronal and behavioural levels is such that it is difficult not to ascribe to the neuron responsibility for the behavioural competence of recognizing of an individual by its face. Certain neurons react not to the size of the retinal image of a face (which varies with distance) but to the absolute size of the image on the screen, which presupposes an ability to compensate for a reduction of the retinal angle as a result of a movement away or its enlargement in the case of a movement toward (Rolls and Baylis 1986). A person standing face to face who turns his head to the right turns it to the left of the viewer. But if his back is turned, the same movement will be to the right of the viewer. That neurons respond in the same way under all conditions demonstrates that they are centred on the object as such (Hasselmo et al. 1989, experi-ment one). Finally, in the same way that the perceptual unity of a face resists attempts to mask certain of its components, those neurons selected for facial recognition still retain a significant level of activity even if one makes the mouth or eyes disappear (Desimone et al. 1984).

In what way do these cells behave differently from the hypothetical grandmother neuron? In this. However differential they might be, their selectivity for faces is not an exclusive selectivity. Those cells that are activated by the face of one individual are often also activated by the faces of other individuals, though often to a different degree. Their constancy with regard to certain variations (size, distance, colour or black and white, contrast, positive or negative, image in two or three dimensions, spatial frequency, position in the visual field, etc.) does not prevent them from responding to other variations (frontal or profile orientation). Not only are the neurons in question close to those which respond differently to the face of the same individual seen from different angles, but those neurons which differentiate individuals in a way which is sensitive to the differences between individuals also modify this response according to the point of view, certain of them displaying a preference for frontal recognition, others for recognition in profile (Hasselmo et al. 1989, experiment two).

These cells do not themselves culminate in a single synthetic terminal in the hierarchy of the stages over which visual information is processed. Nor are there any cells higher up in the hierarchy which would bring about this synthesis further on. As alternative solutions to the grand-mother neuron, we now find concepts of “the continuous mapping of a space composed of complex features” (Tanaka 1996), or “the dispersed distribution of encoding populations” (Rolls 1995). According to Tanaka, the neurons of the infra-temporal regions are organized in columns re-grouping those cells which are sensitive to similar stimuli. Columns dedicated to different but connected stimuli overlap in such a way as to induce a displacement of the focus of activation from one column to the other. Changes in visual features give rise to a domain of complex visual traits whose mapping is ensured in a continuous fashion thanks to the transitivity of this simultaneous activation of numerous cells from one column to another. In this way, one gets by without having to resort to the cell representative of the concept of a face. In the same way, for Rolls, the dispersion of the encoding process of a group of stimuli over a whole population of neurons is a necessary condition for the good discrimination of these stimuli because only so is it possible to compare subtle differences between them. This property of dispersed distribution of the process of encoding ensures the reproduction of an individual face thanks to the enlistment of a group of neurons amongst which different members can be specific to the differentiation of different aspects of the face. The combination of the neuronal activities specific to the differentiation of aspects of a face with those activities specific to the recognition of its individuality, dynamically brought about by the whole population of neurons, would be quite impossible in the case of a single cell.

These cells establish the links in a cortico-subcortical circuit necessary for social interaction. In turn, the latter condition both the formation and the maintenance of the former. Collectively, they operate as a filter for the recognition of visual stimuli such as faces in general and within the sphere of facial recognition, for the identification of individual faces. Transmitted to the amygdala and to the orbito-frontal cortex and cingulum, this information makes possible the attribution to a specific individual of an emotional and motivational value, whether positive or negative, and from there, an appropriate orientation for the interaction of the agent with the individual in question. In the absence of some such identification his conduct would respond to dissociated aspects of one and the same individual instead of responding, in a unitary fashion, to the whole individual and so would display a much greater incoherence than is normally the case.

It is the ability of the relevant neurons to “codify objects” which have made facial recognition cells interesting to researchers; more particularly, their ability to be selectively activated by objects as such and not just simply by elementary features of the visual image or by aspects of objects relative to a point of view. The replacement of the notion of object detector with that of the construction of the concept of an object and the recognition of the flexible and non-localizable character of this constructive process have gone along with the admission of its dependence upon experience (as opposed to the dogma of genetic determination or precocious fixation after a period of latency). A few minutes exposure to a new object is enough for a neuron to modify its response as a function of this new object without endangering its responses to familiar objects, with the result that objects remain perfectly distinguishable even while their number increases. The attention paid to this dynamic dimension of neuronal metabolism underlying perception has conferred a new value upon the information acquired in the course of the active exploration and manipulation of objects. Could this be the first step towards the recognition of the constitutive role played by the action of the perceiving subject in the objectification of things perceived?

2 Neurobiological Foundations of the Experience of the Own Body

In the course of the last twenty years the mapping of the regions responsible for the representation of the body in the brain seems to have changed orientation. Until then, what was primarily sought was to set up one or several topographical maps of the different parts of the body, on the assumption that the principal function of the brain would be to represent them centrally. In the final analysis no particular difficulty was anticipated with this concept of “representation” because it was thought that it could be kept within the limits of a simple projection. The cutaneous surfaces (or the muscular apparatus of the motor organs) would be projected upon the cytoarchitechtonic areas of the cerebral cortex with a distortion attributable to differences in the density of the receptors in different peripheral regions. Even in the pioneer work of Penfield, for example, it is impossible to avoid noting a contrast (Penfield and Boldrey 1937). On the one hand, a review of the preoperative electrical explorations of the cerebral cortex brings to light “the great topographical variability from one patient to another” of the points stimulated even for one and the same category of movement or sensation. On the other hand, this admission does not undermine the localizational consensus which governs the construction of a standardized (distorted) representational map of parts of the body in the rolandic cortex, as being that of the sensory-motor homunculus. But, as the expression of the constancy of a normal functional localization, this homunculus results in fact from a normalization which has eliminated all variability from the data, imputing the latter at times to the electrical current operative on the cortex, an experimental artefact, at other times, to pathological disorganization caused by the onset of epilepsy or a tumour.

Henceforward, researchers have been more interested in the plasticity of these cerebral representations, in all its forms: their individual variability, their modification in the course of life, their remodelling by experience, the use made of them, visual attention and motor intention, their amplification by the learning of a task, implying eventually the manipulation of a tool, their restructuring following upon the amputation of a limb or a cerebral lesion, functional re-education, the use of a prosthesis, etc. At the same time, the functional meaning of the existence of these sup-posed representations in the brain is beginning to be unveiled. The latter are now regarded as so many ways in which schemas of action are temporarily inscribed and in which more long-lasting aptitudes are acquired and also more generally in which the subjective experience of the body, with all its vicissitudes and anomalies, is sustained. All this evidence of an essential, and not merely accidental, anatomical and functional mutability tends logically towards a conclusion that the researchers seem not yet to have drawn; namely, that the relation between the body and the brain is not conceivable in terms of representation, even though these are the terms in which it is currently conceptualized. In fact, the present terminology of the neurosciences: representation, model, schema, image, code, etc., has been borrowed from cognitive ideology. It is clear that this terminology is inadequate to recent discoveries which argue persistently in favour of a dynamic and motor conception. Implicitly regulated by the geometric model of a projection point by point, image upon image, the use of these terms forces upon the interpretation of the data a prejudice that gives an explanatory supremacy to the anatomical structure of the body in its conventional description over the functional metabolism of the brain. Which then constitutes a handicap for the comprehension of the real relation between body and mind, about which a great deal has al-ready been discovered even without a conceptual network adequate for its description, in particular, one which takes account of a dynamic interaction between two poles — themselves related to a third pole: the world — each of which continually both generates and sustains the others in and through this relation.

3 Neurobiological Foundations of the Relation to the Other

Are the psychological and neurobiological foundations of the relation to the other adequately understood once they have been conceptualized in terms of a theory of internal representations in a solipsistic mind-brain together with the computations bearing upon these representations by this mind-brain? An intellectual construction of this kind brings all the modalities of this relation down to so many ways of representing internally the behaviour of a physical system in its environment, of explaining it and predicting its future ramifications, an intellectual activity engaged in by a pure epistemological subject cut off from the object represented. Bringing the relation to the other, that is, a relation encompassing every kind of interaction between a subject of perception and action and an-other subject of perception and action, down to this, is a matter of wanting to construct the relation to the other on the basis of the relation to oneself — and so to set out from presuppositions which are self-defeating.

Too often one forgets the history of discoveries. For the latter often provides a good guide for their interpretation. The discovery of the “mirror neuron” by Rizzolatti and his team did not come as the culmination of a process of neuronal implementation of some “theory of the other mind”. These researchers were engaged in registering the pre-motor neurons of the frontal region 5, neurons officially held responsible for encoding the repertoire of the monkey’s manual movements. Taking advantage of a break to take a bite to eat in close proximity to the implanted animal, they were surprised to hear all over again the neuron’s potential for action. Hence their idea of testing the monkey continuously while (1) watching the act of taking food and (2) taking food themselves. Hence too, their hunch with respect to the existence of a clearly non-inferential mechanism operating either at the motor or pre-motor level, and responsible for reproducing the repertoire of actions corresponding to those they observed in others. This effect was then finally demonstrated in humans watching an agent execute manual movements. Muscular potentials were aroused in the right hand by transcranial stimulation of the Broca region corresponding to F5 (Fadiga 1995).

One might be tempted to think that these results establishing the direct and immediate character of the grasp by an agent of the intentions of the other across his observed movements would be enough to refute any mediate theorizing about the foundations of the relation to the other based on representational computation. All the more so since, in their writing up of these findings, the authors were careful enough to stick to the minimalist hypothesis that there might exist, in the region 5, a system of sympathetic inducement of the relevant schemas of action enabling each actor-observer to detect in movements observed with respect to others those actions which belong to his own repertoire. With the result that the primary object of this perception is not the uninterpreted manual movement awaiting its interpretation as an intentional action through a more elevated operation of perceptual categorization deriving from an attributive judgment. The action itself, as a complex stimulus, is the object of perception, apprehended as it is with that directing intention that characterizes it for an agent equipped with a certain repertoire of actions. And its perception mobilizes the motor system as much as it does the visual system. Independently of linguistic expression, or of any procedure of logical inference, one and the same basic principle lies at the root of my ability to accomplish familiar actions and to unveil the motor intentions of the other.

4 Re-establishing the Pluralism of Philosophical Interpretations

With regard to the objectivist tendencies in the neurosciences, it should by now be clear that once they have been given sufficient latitude they tend to become increasingly conscious of their own limitations and tend to seek out ways and means of counter-balancing their effects by developing what might be called anti-objectivist tendencies. There is no reason to suppose that this process is not recurrent and that objectivism and anti-objectivism do not constitute the two fundamental and inseparable postulates of the very enterprise of objectifying the subjective which is in question in the neurosciences — as in any science. However in the same way that objectivism has found its ideology in the philosophy of mind as men-tal representation, so it becomes important to seek out an alternative philosophical doctrine capable of reconciling, integrating and interpreting the signs of anti-objectivism which we have uncovered in this present review of empirical research. My proposal is that phenomenology, more particularly, the Husserlian theory of transcendental constitution is the best candidate for this role, and for the following reason.

An approach to perceptual experience as act ought to be a strictly correlational approach, one that never separates the subjective from the objective pole of the experiences in question (perception, action, memory, fiction). Only in this way will we be able to put an end to this metaphysical Ping-Pong, alternatively extrovert in our forgetfulness of what objects are for someone and introvert in our ignorance of the essence of representations (which are in themselves nothing outside their relation to “external things”). Putting intentionality first, one can get rid of the principle of the a priori of an exterior thing pre-constituted independently and in ad-vance of our encounter with it, a purely contingent event in the experience of a subject, a thing which in consequence (and in contradiction with itself) ought not even to be able to get into the mind of the subject and be received by it. As absolute entities, mutually indifferent vis-a-vis each other, subject and object are from then on reduced to being opposed poles, each referring to the other in a circular and dynamic relation on which they depend for their very existence. Each cogito is an act that is realized in the positing of its object as one and the same. Each object is the goal of some meaningful directive, a unifying pole, fulfilling multiple anticipations. The advantage of this alternative approach is that one succeeds in dragging the subject and object out of their mutual indifference by viewing each in its reference to the other in the context of lived experience and the continual flux that forms this experience. The substitution of the correlation noesis-noema (Husserl, Ideen I) for the dyad sub-ject-object is an expression of this approach. The noesis is the subjective activity which traverses, animates and unifies the multiple configurations of momentary sensorial fields by linking them up one with the other and so making it possible for the course of experience to yield a possible “something”. The noema is neither consciousness itself nor the object. As the unifying pole of the noetic synthesis without which the latter would be dispersed across the multiplicity it encompasses, it accomplishes a transitory cut across the course of the process of determination: it is the object as it is in its mode of apprehension.

4.1 Intentionality in the Constitution of the Thing

 

The incarnation of meaning in concrete experience is ensured by the promotion of the kinaesthetic function to the status of a constitutional operator. Except that intentionality cannot do its work without a transition between kinaesthesia. In the first instance the meaning, initially floating on the perceptual horizon, is strictly contextualized by the movements of the body. The arrow of intentional consciousness, which traverses and links up the outline of momentary visual fields in proportion as I move around in the course of exploring the visual scene, flies ahead prolonging the finite series of actual changes of image into the infinite series of those images which remain possible along the same trajectory. But if this consciousness is capable of grasping the thing itself across the outlines by means of which it presents itself, it is because each outline bears within itself a meaningful reference to the one that follows and because the movements of the body furnishes precisely that outline which satisfies this intention of unity and identity. If the visual field anticipated at some later time cut across the actual scene in an unpredictable way, the consciousness of unity would be incapable of holding out. The images that make up the field can figure as outlines, and so uphold intentionality, only under normal kinaesthetic circumstances.

All the same, the contribution of kinaesthesia to the constitution of the visual thing goes no further than being the agent responsible for variation and re-contextualization and so is limited to unfolding the visual field under the control of a stage manager, which is the act of apprehension insofar as it projects the thing across its outlines. The sensations which advise me of the movements of my perceptual organs do not themselves supply this projective presentation of the thing. Neither the enjoyment of my freedom of movement, nor the production of an effort of will, nor the tiredness which comes from the expenditure of muscular energy are capable in themselves of conferring upon kinaesthesia the ability to fill out an extension with qualified material (red, over there) and to fuse these extensions to form a field — as do visual and tactile sensations. From posture to posture, what could this kinaesthetic procession be if not a gradation of tension-relaxation whose continuity does not require any intentional reference from phase to phase? Wholly taken in hand by the directing ray of visual attention, intentionality still has to be regarded as emanating from the subject.

4.2 Intentionality in the Constitution of the Own Body

The concept of kinaesthesia revolves around the proprioceptive (senso-rial) or practical (voluntary) duality lying at the root of the “I move”. In the constitution of the physical thing, the only approach taken account of was the proprioceptive, its role being that of sorting out the changes in the outlines due to the movements of the thing and distinguish them from those due to the movements of the embodied subject. The variation in the visual field was the same whether these movements were voluntarily brought about or passively registered. In both cases it was simply a mat-ter of a new series of lateral aspects developed in perspective. In the constitution of the own body as mine, on the other hand, the duality of kin-aesthetic sensations is, for the first time, brought into play. Movement and position are sensed in the contribution they make to the localization of tactile qualities and their integration in a continuous surface which envelopes the hand touched. From one place to the next, touch sensations are engendered in relation to the activity of touching. Inherent in my mo-tor intentions even before any sensorial impact, this experience makes itself known in each reversal of the touching-touched relation, the rela-tion through which I realize the appropriation of the physical body which thereby gets constituted as my own inasmuch as I can move it when I want to.

Nobody could fail to be aware of the central importance of this kin-aesthetic constitution of the own body. However, it is much less a matter of imposing a sensorial configuration upon the “natural” anatomy than of developing the practical usefulness of our body through the realization of our motor intentions. Two kinaesthetic systems have to be distinguished. A first system relates to orientation in perspective. It covers all objects whose aspects vary from the distant horizon to that sphere of the immediate availability of things which puts them “within reach”. The other sys-tem seems at first to be centred on an unextended point, the point at which the axes of the perceived world intersect. The experience of the tool, “non-kinaesthetic extension of the own body”, suggests its reinterpretation as a system in functional equilibrium with the first. In fact, any object which I take hold of and carry along with me or which I use (Heidegger’s hammer) is immediately divested by me of its initial condition of being an object of visual perception with a view to being incorporated into the ownness sphere as the vector of my intentions, woven into its practical resources, whether explicit or hidden, into that very kinaesthetic system set up with its handling.

4.3 Intentionality in Inter-subjective Constitution.

Goal directed intentionality yields things; ground based intentionality yields the own body; transferential intentionality, or empathy, establishes the exposure to the other of one’s own experience inasmuch as it enriches the kinaesthetic system with the possibility of a resonance with that of the other in the perception of the bodily (and expressive) movements of another agent. For Lipps, Einfühlung gave direct access to the interior life of the other. It is only in a second reflection that we succeed in separating this life of the other from our own subjective life. For Husserl, what characterizes the perception of the other is the absence of any direct experi-ence of his mentality. With regard to the other, as with regard to any other physical body, one part is given directly — the front of his body. But a complete experience even of his body requires reference to those parts which are not given, which are prefigured as accessible in the further course of experience — the views from the side and from the back. In addition, we perceive his body as own body, bearer of sensorial and kinaesthetic fields, but we have no direct experience of the red perceived by, nor of the voluntary movement of, the other. When we look at other human bodies, impression of movement can get associated with this empathic insight. But they refer to an experience of “I feel”, “I move my body” which is not given to us. We simply know that from that point of view over there, there is another sensorial field, another space, another freedom which is not anchored in our own self-apperception. But if we integrate into the horizon of the perception of the other the quasi-given empathic insight into his kinesthesia and his subjective life, the fact that they are always promised without ever being given, then, instead of a cognitive deficiency in the perception of the other, we find ourselves in the presence of the essence of the other, confronted with the historical and hermeneutic (non-sensorial) comprehension of intersubjectivity.

5 Some Suggestions for a Neurophenomenology

5.1 A Neural Correlate for the Noema of a Face

 

We have seen that the conditions of activation of the face recognition cells are associated at varying degrees with (1) a relative invariance which resists isomorphic transformations (rotation, colour, size, distance, etc.) and (2) a relative sensitivity to changing points of view or aspects (frontal or profile, eye orientation). This suggests the existence of a sys-tem of analysis and recognition of faces that proceeds by an associative synthesis of relevant information and an active filtering of non-relevant information that is not excluded solely in virtue of a matching of the stimulus with a concept stored in memory. In the functional (non anatomical) configuration of this process I would be ready to see a correlate of the noema of a face (as an example of a fully individualized object). Like the noema, this functional configuration possesses the dialectical polarity of the moments of the “pure something = x” referring to the individuality of the thing in itself and of the perceived as such of the object in the how of its determinations and indeterminations, both of which are given in the flux of an experience of perception and action.

5.2 A Neural Correlate for the Noema of the Own Body

 

To Husserl’s intuition that the intentionality of action contributes to our sense of the own body there corresponds the hypothesis that functional somatotopy is sensitive to efferent intracortical signals, re-entrant and re-afferent, thanks to which the somatomotor and somatosensorial maps influence each other throughout the entire experience of the subject. That the localization of subjective properties in the body requires the integration of tactile fields and practical kinesthesia is due to the fact that the somatotopy of the cortical representation of the sensitive regions of the body is mediated by the use the subject makes of its own body and from there, by the motor somatotopy of its voluntary action together with the inscription of the latter in memory as a motor schema. The complete circuit of these mediations accounts for the spatialization of the experience of the subject acting in its own body at the level of the cerebral metabolism. With the result that what we call “the body” emerges from its persistently internal reconfiguration at every level, whether that of perception (visual, tactile and proprioceptive) or of muscular control, even be-fore this, of motor schemas, and even earlier still, of intentionality.

5.3 A Neural Correlate for the Noema of the Other?

 

Even if at first Rizzolatti seemed to have wanted to say that the mirror neurons which activate manual actions (whether of the monkey itself or the experimenter in front of it) compared and identified internal motor representations with external perceptual representations, his later state-ments leave no doubt about the fact that it is the power to carry out oneself the actions observed which make the meaning of the action directly accessible to the agent, who is also this spectator (di Pellegrino et al. 1992; Rizzolatti 1996, 1997). The way this system is set up makes of the motor schema of actions within the repertoire of the individual the neural correlate of a rudimentary hermeneutics of the behaviour of the other. As it is not unlikely that we have here a somatic source of the communication envisaged in the phenomenology of Einfühlung, this discovery has aroused the hope of gaining access to the neurobiological foundations of intersubjectivity in the near future. This is to place a heavy burden on the shoulders of the mirror neurons. For even if no doubt is cast upon the claim that cerebral systems enter into resonance during periods of motor learning in particular, this imitative empathy is still not intersubjectivity. Why? Because only just having left behind the happy innocence of Nature, it still remains in ignorance of the drama of socialization, the tragic historicity of personal and social development.

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