The River of Consciousness

by Oliver Sacks

  Although Jackson’s views had first arisen in reference to certain epileptic seizures (we still speak of these as “Jacksonian” seizures), they were then applied to a variety of neurological diseases, as well as to dreams, deliriums, and insanities, and in 1879 Jackson applied them to the problem of aphasia, which had long fascinated neurologists interested in higher cognitive function.

  In his own 1891 monograph On Aphasia, a dozen years later, Freud repeatedly acknowledged his debt to Jackson. He considered in great detail many of the special phenomena that may be seen in aphasias: the loss of new languages while the mother tongue is preserved, the preservation of the most commonly used words and associations, the retention of series of words (days of the week, for example) more than single ones, the paraphasias or verbal substitutions that might occur. Above all, he was intrigued by the stereotyped, seemingly meaningless phrases that are sometimes the sole residue of speech and which may be, as Jackson had remarked, the last utterance of the patient before his stroke. For Freud, as for Jackson, this represented the traumatic “fixation” (and thereafter the helpless repetition) of a proposition or an idea, a notion that was to assume a crucial importance in his theory of the neuroses.

  Further, Freud observed that many symptoms of aphasia seemed to share associations of a more psychological rather than physiological sort. Verbal errors in aphasias might arise from verbal associations, with words of similar sound or similar meanings tending to be substituted for the correct word. But sometimes the substitution was of a more complex nature, not comprehensible as a homophone or synonym, but arising from some particular association that had been forged in the individual’s past. (Here there was an intimation of Freud’s later views, as set out in The Psychopathology of Everyday Life, of paraphasias and parapraxes as interpretable, as historically and personally meaningful.) Freud emphasized the need to look at the nature of words and their (formal or personal) associations to the universes of language and psychology, to the universe of meaning, if we wish to understand paraphasias.

  He was convinced that the complex manifestations of aphasia were incompatible with any simplistic notion of word images lodged in the cells of a “center,” as he wrote in On Aphasia:

  The theory has been evolved that the speech apparatus consists of distinct cortical centers; their cells are supposed to contain the word images (word concepts or word impressions); these centers are said to be separated by functionless cortical territory, and linked to each other by the association tracts. One may first of all raise the question as to whether such an assumption is at all correct, and even permissible. I do not believe it to be.

  Instead of centers—static depots of words or images—Freud wrote, one must think of “cortical fields,” large areas of cortex endowed with a variety of functions, some facilitating, some inhibiting each other. One could not make sense of the phenomena of aphasia, he continued, unless one thought in such dynamic, Jacksonian terms. Such systems, moreover, were not all at the same “level.” Hughlings Jackson had suggested a vertically structured organization in the brain, with repeated representations or embodiments of function at many hierarchic levels—thus when higher-level, propositional speech has become impossible, there might still be the “regressions” characteristic of aphasia, the (sometimes explosive) emergence of primitive, emotional speech. Freud was one of the first to bring this Jacksonian notion of regression into neurology and to import it into psychiatry; one feels, indeed, that Freud’s use of the concept of regression in On Aphasia paved the way to his much more extensive and powerful use of it in psychiatry. (One wonders what Hughlings Jackson might have thought of this vast and surprising expansion of his idea, but though he lived until 1911, we do not know whether he had ever heard of Freud.)*3

  Freud went beyond Jackson when he implied that there were no autonomous, isolable centers or functions in the brain but, rather, systems for achieving cognitive goals—systems that had many components and which could be created or greatly modified by the experiences of the individual. Given that literacy was not innate, for example, he felt it was not useful to think of a “center” for writing (as his friend and former colleague Sigmund Exner had postulated); one had, rather, to think of a system or systems being constructed in the brain as the result of learning (this was a striking anticipation of the notion of “functional systems” developed by A. R. Luria, the founder of neuropsychology, fifty years later).

  In On Aphasia, in addition to these empirical and evolutionary considerations, Freud laid great emphasis on epistemological considerations—the confusion of categories, as he saw it, the promiscuous mixing of physical and mental:

  The relationship between the chain of physiological events in the nervous system and the mental processes is probably not one of cause and effect. The former do not cease when the latter set in…but, from a certain moment, a mental phenomenon corresponds to each part of the chain, or to several parts. The psychic is, therefore, a process parallel to the physiological, “a dependent concomitant.”

  Freud here endorsed and elaborated Jackson’s views. “I do not trouble myself about the mode of connection between mind and matter,” Jackson had written. “It is enough to assume a parallelism.” Psychological processes have their own laws, principles, autonomies, coherences, and these must be examined independently, irrespective of whatever physiological processes may be going on in parallel. Jackson’s epistemology of parallelism or concomitance gave Freud an enormous freedom to pay attention to the phenomena in unprecedented detail, to theorize, to seek a purely psychological understanding without any premature need to correlate them with physiological processes (though he never doubted that such concomitant processes must exist).

  As Freud’s views evolved in relation to aphasia, moving from a center or lesion way of thinking towards a dynamic view of the brain, there was an analogous movement in his views on hysteria. Charcot was convinced (and had convinced Freud at first) that although no anatomical lesions could be demonstrated in patients with hysterical paralyses, there must nonetheless be a “physiological lesion” (an état dynamique) located in the same part of the brain where, in an established neurological paralysis, an anatomical lesion (an état statique) would be found. Thus, Charcot conceived, hysterical paralyses were physiologically identical with organic ones, and hysteria could be seen, essentially, as a neurological problem, a special reactivity peculiar to certain pathologically sensitive individuals or “neuropaths.”

  To Freud, still saturated in anatomical and neurological thinking and very much under Charcot’s spell, this seemed entirely acceptable. It was extremely difficult for him to “de-neurologize” his thinking, even in this new realm where so much was mysterious. But within a year he had become less certain. The whole neurological profession was in conflict over the question of whether hypnosis was physical or mental. In 1889, Freud paid a visit to Charcot’s contemporary Hippolyte Bernheim in Nancy—Bernheim had proposed a psychological origin for hypnosis and believed that its results could be explained in terms of ideas or suggestion alone—and this seems to have influenced Freud deeply. He had begun to move away from Charcot’s notion of a circumscribed (if physiological) lesion in hysterical paralysis towards a vaguer but more complex sense of physiological changes distributed among several different parts of the nervous system, a vision that paralleled the emerging insights of On Aphasia.

  Charcot had suggested to Freud that he try to clarify the controversy by making a comparative examination of organic and hysterical paralyses.*4 This Freud was well equipped to do, for when he returned to Vienna and set up his private practice, he started to see a number of patients with hysterical paralyses and, of course, many patients with organic paralyses, too, and to attempt to elucidate their mechanisms for himself.

  By 1893 he had made a complete break with all organic explanations of hysteria:

  The lesion in hysterical paralyses must be completely independent of the nervous system, since in its paralyses and other manifestations hy
steria behaves as though anatomy did not exist or as though it had no knowledge of it.

  This was the moment of crossover, of transit, when (in a sense) Freud would give up neurology, and notions of a neurological or physiological basis for psychiatric states, and turn to looking at these states exclusively in their own terms. He was to make one final, highly theoretical attempt to delineate the neural basis of mental states in his Project for a Scientific Psychology, and he never gave up the notion that there must ultimately be a biological “bedrock” to all psychological conditions and theories. But for practical purposes he felt he could, and must, put these aside for a time.

  Though Freud had turned increasingly to his psychiatric work in the late 1880s and the 1890s, he continued to write occasional shorter papers on his neurological work. In 1888 he published the first description of hemianopsia in children, and in 1895 a paper on an unusual compression neuropathy (meralgia paresthetica), a condition he himself suffered from and which he had observed in several patients under his care. Freud also suffered from classical migraine and saw many patients with this in his neurological practice. At one point he apparently considered writing a short book on this subject, too, but, in the event, did no more than make a summary of ten “Established Points” which he sent to his friend Wilhelm Fliess in April 1895. There is a strongly physiological, quantitative tone in this summary, “an economics of nerve-force,” which hinted at the extraordinary outburst of thought and writing that was to occur later in the year.

  It is curious and intriguing that even with figures like Freud, who published so much, the most suggestive and prescient ideas may appear only in the course of their private letters and journals. No period in Freud’s life was more productive of such ideas than the mid-1890s, when he shared the thoughts he was incubating with no one except Fliess. Late in 1895, Freud launched an ambitious attempt to bring together all his psychological observations and insights and ground them in a plausible physiology. At this point his letters to Fliess are exuberant, almost ecstatic:

  One evening last week when I was hard at work…the barriers were suddenly lifted, the veil drawn aside, and I had a clear vision from the details of the neuroses to the conditions that make consciousness possible. Everything seemed to connect up, the whole worked well together, and one had the impression that the Thing was now really a machine and would soon go by itself….Naturally I don’t know how to contain myself for pleasure.

  But this vision in which everything seemed to connect up, this vision of a complete working model of the brain and mind which presented itself to Freud with an almost revelatory lucidity, is not at all easy to grasp now (and indeed Freud himself wrote, only a few months later, “I no longer understand the state of mind in which I hatched out the ‘Psychology’ ”).*5

  There has been intensive discussion about this Project for a Scientific Psychology, as it is now named (Freud’s working title had been “A Psychology for Neurologists”). The Project makes very difficult reading, partly because of the intrinsic difficulty and originality of many of its concepts; partly because Freud uses outmoded and sometimes idiosyncratic terms that we have to translate into more familiar ones; partly because it was written at furious speed in a sort of shorthand; and perhaps because it might never have been intended for anyone’s eyes but his own.

  And yet the Project does bring together, or attempts to bring together, the domains of memory, attention, consciousness, perception, wishes, dreams, sexuality, defense, repression, and primary and secondary thought processes (as he called them) into a single coherent vision of the mind, and to ground all of these processes in a basic physiological framework, constituted by different systems of neurons, their interactions and modifiable “contact barriers,” and free and bound states of neural excitation.

  Though the language of the Project is inevitably that of the 1890s, a number of its notions retain (or have assumed) striking relevance to many current ideas in neuroscience, and this has caused it to be reexamined by Karl Pribram and Merton Gill, among others. Pribram and Gill, indeed, call the Project “a Rosetta stone” for those who wish to make connections between neurology and psychology. Many of the ideas Freud advanced in the Project, moreover, can now be examined experimentally in ways that would have been impossible at the time they were formulated.

  The nature of memory occupied Freud from first to last. Aphasia he saw as a sort of forgetting, and he had observed in his notes that an early symptom in migraine was often the forgetting of proper names. He saw a pathology of memory as central in hysteria (“Hysterics suffer mainly from reminiscences”), and in the Project he attempted to explicate the physiological basis of memory at many levels. One physiological prerequisite for memory, he postulated, was a system of “contact barriers” between certain neurons—his so-called psi system (this was a decade before Sherrington gave synapses their name). Freud’s contact barriers were capable of selective facilitation or inhibition, thus allowing permanent neuronal changes that corresponded to the acquisition of new information and new memories—a theory of learning basically similar to one that Donald Hebb would propose in the 1940s and which is now supported by experimental findings.

  At a higher level, Freud regarded memory and motive as inseparable. Recollection could have no force, no meaning, unless it was allied with motive. The two had always to be coupled together, and in the Project, as Pribram and Gill emphasize, “both memory and motive are psi processes based on selective facilitation…memories [being] the retrospective aspect of these facilitations; motives the prospective aspects.”*6

  Thus remembering, for Freud, though it required such local neuronal traces (of the sort we now call long-term potentiation), went far beyond them and was essentially a dynamic, transforming, reorganizing process throughout the course of life. Nothing was more central to the formation of identity than the power of memory; nothing more guaranteed one’s continuity as an individual. But memories shift, and no one was more sensitive than Freud to the reconstructive potential of memory, to the fact that memories are continually worked over and revised and that their essence, indeed, is recategorization.

  Arnold Modell has taken up this point with regard to both the therapeutic potential of psychoanalysis and, more generally, the formation of a private self. He quotes a letter Freud wrote to Fliess in December 1896 in which he used the term Nachträglichkeit, which Modell feels is most accurately rendered as “retranscription.”

  “As you know,” Freud wrote,

  I am working on the assumption that our psychic mechanism has come into being by a process of stratification, the material present in the form of memory traces being subjected from time to time to a rearrangement in accordance with fresh circumstances—a retranscription….Memory is present not once but several times over…the successive registrations representing the psychic achievement of successive epochs of life….I explain the peculiarities of the psychoneuroses by supposing that this translation has not taken place in the case of some of the material.

  The potential for therapy, for change, therefore, lies in the capacity to exhume such “fixated” material into the present so that it can be subjected to the creative process of retranscription, allowing the stalled individual to grow and change once again.

  Such remodelings, Modell feels, not only are crucial in the therapeutic process but are a constant part of human life both for day-to-day “updating” (an updating which those with amnesia cannot do) and for the major (and sometimes cataclysmic) transformations, the “revaluations of all values” (as Nietzsche would say) which are necessary for the evolution of a unique private self.

  That memory does construct and reconstruct, endlessly, was a central conclusion of the experimental studies carried out by Frederic Bartlett in the 1930s. Bartlett showed in these, very clearly (and sometimes very entertainingly), how with retelling a story—either to others or to oneself—the memory of it is continually changed. There was never, Bartlett felt, a simple mechanical reproduction in memory;
it was always an individual and imaginative reconstruction. He wrote,

  Remembering is not the re-excitation of innumerable fixed, lifeless and fragmentary traces. It is an imaginative reconstruction, or construction, built out of the relation of our attitude towards a whole active mass of organized past reactions or experience, and to a little outstanding detail which commonly appears in image or in language form. It is thus hardly ever really exact, even in the most rudimentary cases of rote recapitulation, and it is not at all important that it should be so.

  Since the last third of the twentieth century, the whole tenor of neurology and neuroscience has been moving towards such a dynamic and constructional view of the brain, a sense that even at the most elementary levels—as, for example, in the “filling in” of a blind spot or scotoma or the seeing of a visual illusion, as both Richard Gregory and V. S. Ramachandran have demonstrated—the brain constructs a plausible hypothesis or pattern or scene. In his theory of neuronal group selection, Gerald Edelman—drawing on the data of neuroanatomy and neurophysiology, of embryology and evolutionary biology, of clinical and experimental work, and of synthetic neural modeling—proposes a detailed neurobiological model of the mind in which the brain’s central role is precisely that of constructing categories—first perceptual, then conceptual—and of an ascending process, a “bootstrapping,” where through repeating recategorization at higher and higher levels, consciousness is finally achieved. Thus, for Edelman, every perception is a creation and every memory a re-creation or recategorization.