* * *
—
In the 1880s the great neurologist Charcot had propounded a task to two of his pupils, Babinski and Freud: the differentiation of the organic (neurological) from hysterical paralyses. The organic paralyses (and anesthesias), Freud found, have patterns which are “strictly in obedience with neuroanatomy,” with the established distribution of nerves, spinal tracts, and their centers in the brain. The hysterical paralyses, by contrast, do not obey these patterns; they are expressions not of anatomical damage in the nervous system, but of concepts and feelings generated by psychic trauma, but then defensively dissociated and repressed. The organic paralyses make anatomic sense, but have no intrinsic psychic component; the hysterical paralyses make psychic or psychodynamic sense, but have no underlying anatomical component. The organic paralyses, to Freud, were “physical,” the hysterical (and, by implication, all others) were “mental.”
This seemed clear enough—a working distinction which all neurologists and psychiatrists could use. Hysteria was often called “the great mimic,” since hysterical paralyses often mimicked organic ones, and an act of characterization and clarification was needed. But Charcot’s question was, in consequence, dichotomous and dualistic, a plea to distinguish the physical and the mental. Unfortunately it had a further, and perhaps unintended, consequence—the implication that all paralyses and anesthesias and non-uses and alienations, if they were not immediately intelligible anatomically, must by default be “hysterical” or “mental.” It disallowed, it paralyzed, any investigation or understanding of any other states—such as the “reflex paralysis” and “negative phantoms” described by Weir Mitchell; and, less dramatic perhaps, but much commoner, the “sparing” of limbs which is seen after injury, a sparing which can long outlast the injury itself (a phenomenon not confined to human subjects, but equally to be observed, as Mr. W.R., the surgeon, remarked, in a dog). It prevented any real exploration of alienation, extinction, and anosognosia. None of these neuropsychological disturbances of body-image and “self” were allowed any place on the scientific map.
Freud’s practice—first neurological, then analytic—did not indeed bring him into contact with such cases, such phenomena; but Babinski’s did, especially in the Great War. Babinski’s 1917 book brought together a mass of observations on paralyses, alienations, non-uses and other syndromes arising in consequence of peripheral injuries, syndromes which could not be called either organic or hysterical—syndromes, he felt, which constituted “a third realm,” and required a wholly different understanding. Such syndromes, Babinski was sure, were physiological in nature; he spoke of them as, and titled his book, Syndrome Physiopathique. Like Weir Mitchell and others before him, he postulated a “shock,” a reflex (probably synaptic) inhibition spreading in the immediate neighborhood of the injury and spinal cord; but then, at a higher level, in the brain, a disturbance akin to the anosognosia, or unawareness of deficit, he had been the first to describe in cases of damage to the right hemisphere of the brain. He wrote at a time before Head’s concept of a plastic “postural schema” or “body-image” had evolved, and without reference to the odd and distinctly unclassical observations Sherrington was making on the day-to-day changes of sensory and motor “points” in the cortex of experimental animals, which showed an unexpected plasticity of the brain. Babinski’s observations, like Sherrington’s and Head’s, contradicted the notions of rigid cerebral localization and representation, the notion of a rigidly programmed cerebral machine which had dominated thought in the nineteenth century, and seemed to point to principles of organization which were altogether different, more plastic, more dynamic, than these.
But it was not for Babinski or Head or Sherrington—or, in a later generation, for Luria or Leont’ev—to grasp the actual mechanisms whose principle they intuited. Nor could I, confronting my own experiences in 1974, and pondering these (and those of other patients) in the years immediately following, make any better sense of these. I saw clearly that such experiences were physiological in origin, but equally that they could not be fitted into the classical model. It was clear to me that we needed “a neurology of identity,” a neurology which could explain how different parts of the body (and their space) could be “owned” (or “lost”), a neurological basis for the coherence and unification of perception (especially after this had been disturbed by damage or disease). We needed a neurology which could escape from the rigid dualism of body/mind, the rigid physicalist notions of algorithm and template, a neurology which could match the richness and density of experience, its sense of scene and music, its personeity, its ever-changing flow of experience, of history, of becoming.
But it was not clear to me how such a neurology could be realized, and I came to make, at the very end of the book, so I have since come to think, a strange aberration into the mystical, Kantian waters of the a priori. I repent, and retract, my Kantian aberration now; but I was driven to it, I think, by the limitations of physiology, and physiological theory, which could not, in the 1970s, encompass my experience, or any of the higher ranges of perception and language. I have not been the first, nor will I be the last, to be driven this way.*5
My 1984 experience, with the right leg, convinced me that time was a crucial element in the maintenance (or dissolution) of body-image. My “good” experience, so different from the 1974 one, had come about partly by luck (I was near a hospital when I had the injury, and could be operated on without delay), and partly through the explicit recognition of the importance of speed in such matters. In 1974 it was common to have a period of bed rest, or limited movement, after limb injuries or amputations, and prolonged body-image disturbances were relatively common. By 1984 approaches had changed radically—a patient scheduled to have a leg amputated would be given a temporary prosthesis immediately after surgery, and encouraged to step down from the operating table using it; and patients like myself, with an injury to the leg, would be given a walking cast, and encouraged to use it straight away. In this way, it was found, one could avoid or minimize any hiatus in action, and one could minimize any shrinkage or change in body-image—I saw for myself how rapidly this could occur when I felt myself “shoulderless” within hours of the application of a cast. That time was of the essence had become common knowledge among orthopedists, though this had yet to be a subject of experimental clarification.
* * *
—
And beyond these questions of body-image (for body-image may be the first mental construct and self-construct there is, the one that acts as a model for all others) were the most general questions about the construction of all perceptual categories, of the (spatial and other) frameworks in which they are placed, about memory, about action, and consciousness, about mind—a whole pyramid of considerations raying up from body-image.
The technical advance which had made investigations of these questions (the most elementary ones, at least) possible has been the use of large arrays of electrodes, allowing the recording of neuronal activity and its vicissitudes simultaneously, in hundreds of neurons, the plotting of extensive sensory maps and fields in the cerebral cortex in the living, stimulated, perceiving subject. Such explorations, not technically possible before 1980, are revolutionizing our understanding of the adult brain and its plasticity; and, in particular, our understanding of body-image disturbances after deafferentation or amputation, and of recovery from these. This work has especially been done by Michael Merzenich in San Francisco.
Merzenich and his colleagues have examined the effects of sensory deafferentation (bandaging and casting the hands, or cutting sensory nerves) and amputations, as well as of tactile stimulation, and use, upon the representation of the hand in the sensory cortex. They have shown that with a cut-off of sensory input in the hand, there is a prompt diminution, or extinction, of its cortical map, along with a prompt reorganization of the remaining inputs. There is no permanent, reserved area, these experiments show, for any
part of the body. There is no fixed “hand” area, for example. If a hand is deafferented or inactivated for any length of time, it loses its place in the sensory cortex. Its place, within hours or days, is rapidly appropriated by the mappings of the rest of the body, so that we now have a new but “handless” body-map in the cortex. The inner representation of the inactivated or deafferented body part vanishes cleanly, totally and seamlessly, without leaving the least residue or trace.
There is never, Merzenich has found, any spontaneous revival or recovery of a cortical map which has vanished; there has to be creation of a new organization, induced by new experiences, new stimuli and actions. Thus body-image is not fixed, as a mechanical, static neurology would suppose; body-image is dynamic and plastic—it must be remodelled, updated all the time, and can reorganize itself radically with the contingencies of experience. “Cortical representational maps in adults are ‘use-dependent,’ ” writes Merzenich; they “operate dynamically throughout life.” Body-image is not something fixed a priori in the brain, but a process adapting itself all the time to experience.*6
What, we might then wonder, is the status of a hand, or leg, or any part of the body, which has lost its inner representation? How does the possessor feel about the loss? And how does he behave? Neurologists use the terms “neglect” and “extinction” for this situation. If there is neglect of a part of the body, or extinction of one’s personal “space” or “field” (which invariably goes with such neglect), the affected animal or person simply does not notice. The neglected limb is indeed neglected: it is ignored, it is treated as if it is not part of the body, the self. This is well known to veterinarians, and a description may be found in one of James Herriot’s delightful books of how a cow, bellowing in obstructed parturition, was given a spinal anesthetic. As soon as this took effect, the cow calmed down, ignored its now paralyzed and anesthetized hindquarters, and quietly resumed munching some hay, paying no attention to, seeming not to notice, the delivery of its calf. This is precisely the reaction of patients when a body part falls out of consciousness, whether from deficits in the brain (especially the right side of the brain) or peripherally. One sees this in patients with tabes, who have lost proprioception in their legs: they tend to get their legs in peculiar, awkward positions—jammed in corners, falling off chairs; their legs get “lost” or “neglected” (that is, unnoticed) when they are not the subject of deliberate, visual attention.*7 And this is what happened with me, when I was not paying attention—this was, indeed, how I learned what had happened: I had fallen asleep, and in sleep had inadvertently pushed my casted leg until it was almost off the bed. It needed Nurse Sulu to come in, aghast, and my own confounded astonishment when I realized what had happened, to show that my own leg had completely fallen out of consciousness, was being “neglected,” treated as an unrelated “thing.”
This too is how it is with Merzenich’s monkeys—after their hands have been denervated, casted, tightly bandaged, or otherwise deafferented. They treat them indifferently, perhaps carelessly, they do not seem to notice them.*8 But they do not stare at them in fascinated horror, they do not seem confounded, they do not seem troubled with a sense of anomaly. Do they even have the concept of “alien”? Is this sense of bewilderment and anomaly and horror, the sense of alienness, placelessness, pastlessness, then, an exclusively human reaction, dependent on the reflective, self-referencing nature of human consciousness? Merzenich’s work on dynamic reorganization in cortical mapping was done in monkeys—and I am a man. Was there anything specifically human about my experience?
This self-reference—a term used by Israel Rosenfield—may be implicit (as when an animal acts as a self, but does not reflect on itself), or explicit (when there is a concept of self). The explicit form of self-reference is the essence of human consciousness, and transforms all experience.*9
None of the animals so far mentioned—Mr. W.R.’s dog, Herriot’s cow, Merzenich’s owl monkeys—are able to report their neglect. Indeed, one cannot draw their attention to it; they simply neglect parts, and that is all.*10 It is similar, at first, if a human being has an injured and neglected limb—he will spare it, pass over it, dismiss it, as I did. But if he attends, once he attends, then things are different: the extinguished part will indeed be perceived now, but perceived and reported as totally alien. If the questions raised by neglect point, in the first place, to the brain’s mapping of the body in the cortex, the far more complex ones raised by alienation point to the structure of consciousness itself.
The structure of consciousness, in general, has not been approached by neurologists until very recently; they have felt, all too often, that consciousness is not their business, but a matter best left to psychiatrists. This, indeed, is a relic of the severe dualism of the last century, which divided phenomena into “physical” or “mental.” It was here, in this previously inadmissible space, that Babinski made his claim for “a third realm”—a realm where organic, objective neurological disorders might nonetheless give rise to disorders of consciousness. Babinski first studied certain cerebral syndromes, disorders (almost invariably) of the right hemisphere of the brain, disorders which extinguished awareness of the left half of the body (and its “space”)—so-called hemi-space neglect or hemi-inattention. Such internal bisections of the body and its space are extraordinary to see, and dramatic in the extreme. Such patients, one may say, live in a half-universe, without realizing that it is a half-universe (because for them, it is unbisected and complete). Thus, commonly, the perception, the idea, the memory, of “leftness” goes.*11 “When the neglect is severe,” writes the neurologist M.-Marcel Mesulam, “the patient may behave as if one half of the universe had abruptly ceased to exist in any meaningful form….Patients with unilateral neglect behave not only as if nothing were actually happening in the left hemi-space, but also as if nothing of any importance could be expected to occur there.”
Since those with hemi-inattention are unaware of their neglect, or anosognosic, they cannot describe or report on it, however great their intelligence: so, tantalizingly, they cannot say what the experience is like. Such patients do not experience a gap or division in consciousness, but show a radically reorganized consciousness, with the new consciousness being experienced as complete and entire.
It is only in the case of an undamaged human brain, confronted with a neglect or extinction of peripheral origin, that the entire powers of attention and higher-order consciousness can be focused upon the phenomenon. Anosognosia is inaccessible to introspection, insight or report.*12 But alienation can be perceived, and reported, with all the reflective power a patient possesses; and this gives it a unique status, unlike anything else in neuropsychology, a unique power to point to the basic structure of consciousness itself (for consciousness here is observing itself, is able to observe a particular form of breakdown in itself).
A patient with such an alienation can dilate on the central paradox of alienation—the feeling of the alienated part; as being not-self. He can observe the disturbance of memory, the paradoxical “amnesia” that goes contrary to what he knows. He can remark the disturbance of personal space (which an agnosic shows, but does not experience). He can articulate a state of radical perplexity, a total breakdown in his inner sense of identity, memory, “space”; but one confined to the domain of a limb, the rest of consciousness being intact and complete. This is precisely what I experienced myself.
Such phenomenological changes require a formulation in terms not of systems, but of selves; require a neurology of identity; require a theory of identity, memory, “space,” which can knit them together, show them as inseparable, aspects of a single, global process. They need, in short, a biological theory of consciousness—but this was not available to me, to anyone, in the 1970s.
* * *
—
Here matters lay for many years, until I became acquainted with the work of Gerald Edelman, and his characterizations of
“primary” and “higher-order” consciousness and their possible neuronal basis. There is not, clearly, a mere registration of inner changes, such as sensory mapping and categorization would provide; there is also a comparison—a comparison of the present with the past, with what is remembered. Primary consciousness is this single process—it is consciousness which arises, so Edelman theorizes, from perceptual categorization, memory, learning and self/non-self discrimination. And from this primary consciousness, a higher-order consciousness evolves in man, with the powers of language, conception and thought. Consciousness, thus conceived, is essentially personal; it is essentially connected to the actual living body, its location and positing of a personal space; and it is based on memory, on a remembering which continually reconstructs and recategorizes itself. Identity, memory and space, for Edelman, go together; together they compose, they define, primary consciousness. But it was precisely these three which vanished when my leg became alien to me. They collapsed and vanished together, leaving an abyss or hole, a hole in memory/identity/space.
A Leg to Stand On Page 20