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Mystery of the Mind: A Critical Study of Consciousness and the Human Brain

Mystery of the Mind: A Critical Study of Consciousness and the Human Brain

Wilder Penfield
Foreword by Charles W. Hendel
Introduction by William Feindel
Reflections by Charles Symonds
Copyright Date: 1975
Pages: 160
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  • Book Info
    Mystery of the Mind: A Critical Study of Consciousness and the Human Brain
    Book Description:

    In the past fifty years scientists have begun to discover how the human brain functions. In this book Wilder Penfield, whose work has been at the forefront of such research, describes the current state of knowledge about the brain and asks to what extent recent findings explain the action of the mind. He offers the general reader a glimpse of exciting discoveries usually accessible to only a few scientists.

    He writes: "Throughout my own scientific career I, like other scientists, have struggled to prove that the brain accounts for the mind. But perhaps the time has come when we may profitably consider the evidence as it stands, and ask the question...Can the mind be explained by what is now known about the brain?"

    The central question, he points out, is whether man's being is determined by his body alone or by mind and body as separate elements. Before suggesting an answer, he gives a fascinating account of his experience as a neurosurgeon and scientist observing the brain in conscious patients.

    Originally published in 1978.

    ThePrinceton Legacy Libraryuses the latest print-on-demand technology to again make available previously out-of-print books from the distinguished backlist of Princeton University Press. These paperback editions preserve the original texts of these important books while presenting them in durable paperback editions. The goal of the Princeton Legacy Library is to vastly increase access to the rich scholarly heritage found in the thousands of books published by Princeton University Press since its founding in 1905.

    eISBN: 978-1-4008-6873-5
    Subjects: Biological Sciences

Table of Contents

  1. Front Matter
    (pp. i-vi)
  2. Table of Contents
    (pp. vii-viii)
  3. Preface
    (pp. ix-xvi)
    Wilder Penfield
  4. Foreword
    (pp. xvii-xxiii)
    Charles W. Hendel

    In his Preface Dr. Penfield tells how I became associated with this piece of writing. I would like here to add something, in order to explain why, as he says, he was led “to rewrite the monograph, making it more frankly a personal account of work and experience.” Earlier in my original letter I had written:

    “As I finish a second reading of your manuscript, I find the last pages are an eloquent, convincing justification of your hypothesis and belief that mind has a being distinct from body, though intimately related to and dependent on body. The final statement is...

  5. Introduction
    (pp. xxiv-2)
    William Feindel

    Perhaps at no previous time in the history of science has there been such widespread interest, as is now evident, in the brain and its function, and how that function relates to human behavior. For compelling and obvious reasons, this topic has always been foremost in the attention of neurologists, neurosurgeons, and psychiatrists. Over many years, as well, the study of the brain has attracted the talents of scientists trained in anatomy, physiology, pathology, and other biological disciplines. Increasing numbers of intellectual emigrés, coming from such fields as mathematics, physics, chemistry, electronics, and computer sciences, have recently added fresh impetus...

  6. 1. Sherringtonian Alternatives—Two Fundamental Elements or Only One?
    (pp. 3-6)

    My professional career was shaped, I suppose, in the neurophysiological laboratory of Professor Sherrington at Oxford. Eventually it was continued in the wards and operating rooms of the Montreal Neurological Institute. Other preoccupations were many and varied, but beneath them all was the sense of wonder and a profound curiosity about the mind. My planned objective, as I turned from studying the animal brain to that of man, was to come to understand the mechanisms of the human brain and to discover whether, and perhaps how, these mechanisms account for what the mind does.

    My teacher, Sir Charles Sherrington, received...

  7. 2. To Consciousness the Brain Is Messenger
    (pp. 7-10)

    Hippocrates, the Father of Scientific Medicine, began to teach in the fifth century b.c. on the little Greek island of Cos. In that time, philosophers such as Empedocles and Democritus were proclaiming each his own explanation of the universe and the nature of man. Hippocrates defied what he called the “unproven hypotheses” of the philosophers, and declared that only the study and observation of nature and of man would point the way to truth.

    He studied man in health and in disease, making of medicine a science and an art. But he saw in man something beyond any discovery that...

  8. 3. Neuronal Action within the Brain
    (pp. 11-13)

    Definitions are useful at the beginning of an essay—although the text, in this case, will certainly show them to be inadequate. Themind(or spirit) is, to quote from Webster’s Dictionary: “the element … in an individual that feels, perceives, thinks, wills, and especially reasons.”

    Thebrainis the vastly complicated master organ within the body that makes thought and consciousness possible. In its integrative and coordinating action, it resembles in many ways an electrical computer. An individualbrain-mechanismis a functional unit that plays a somewhat specialized role in the total integrative action of the brain.

    Each nerve...

  9. 4. Sensory and Voluntary-Motor Organization
    (pp. 14-17)

    Here, then, is a brief outline of the sensory and motor mechanisms and of some of the inborn reflexes that play roles in theintegrative actionof the brain of man and other mammals. I hope it may serve as a preparation for some readers and a review or revision for others, before I pass on to the discussion of brain-mechanisms that are more closely related to the action of the mind.

    The brain-stem and the spinal cord provide man with inborn reflexes, as they do the other mammals. They regulate such things as muscle tone, maintenance of posture, mechanics...

  10. 5. The Indispensable Substratum of Consciousness
    (pp. 18-20)

    Gradually it became quite clear in neurosurgical experience, that even large removals of the cerebral cortex could be carried out without abolishing consciousness. On the other hand, injury or interference with function in the higher brain-stem, even in small areas, would abolish consciousness completely.

    An invitation to give the Harvey Lecture at the New York Academy of Medicine caused me to review and reconsider functional localization in 1938.14In summary, this was the conclusion:

    There is much evidence of a level of integration within the central nervous system that is (functionally) higher than that to be found in the cerebral...

  11. 6. The Stream of Consciousness Electrically Reactivated
    (pp. 21-27)

    In the course of surgical treatment of patients suffering from temporal lobe seizures (epileptic seizures that are caused by a discharge that originates in that lobe), we stumbled upon the fact that electrical stimulation of the interpretive areas of the cortex occasionally produces what Hughlings Jackson had called “dreamy states,” or “psychical seizures” (Jackson3,4). Sometimes the patient informed us that we had produced one of his “dreamy states” and we accepted this as evidence that we were close to the cause of his seizures.*It was evident at once that these were not dreams. They were electrical activations of the...

  12. 7. Physiological Interpretation of an Epileptic Seizure
    (pp. 28-30)

    In 1958, after I had accumulated considerable clinical experience, I reconsidered critically the physiology involved in the electrical exploration of the human brain. This was reported in the Sherrington Lecture.18I realized that when an electrode passes a current into the cerebral cortex, the current interferes completely with the patient’s normal use of that area of gray matter. In some areas, there is no evidence of any further effect. For example, as shown in Figure 6, an electrode on one of the three areas of speech cortex causes aphasia. But, in other areas, as explained in Table I, stimulation gives...

  13. 8. An Early Conception of Memory Mechanisms—And a Late Conclusion
    (pp. 31-33)

    This late understanding of the physiology of electrical stimulation, and of the pattern of neuronal discharge in an epileptic seizure, led at once to a clearer understanding of what is taking place in eachexperiential responseto electrical stimulation. It called for a reconsideration of the “flashbacks.” Consequently, after the close of my own career as an operating neurosurgeon in 1960, we reconsidered and published every detail of the experiential responses so others might judge their meaning for themselves. These were presented by Penfield in the Lister Oration, Royal College of Surgeons, in 1961, and published in full with Phanor...

  14. 9. The Interpretive Cortex
    (pp. 34-36)

    Let me marshal and reconsider the evidence now presented to us by epilepsy and the electrode, after which we may go on to a consideration of the relationship of mind to brain, in Chapters 10 to 16.*

    Two related mechanisms are revealed by stimulation of the interpretive cortex (Figures 7 and 8). Each of them was activated in Case m.m. above:

    (a) There is a brain mechanism, the function of which is to send neuronal signals that interpret the relationship of the individual to his immediate environment. The action is automatic and subconscious, but the signal appears in consciousness. Such...

  15. 10. An Automatic Sensory-Motor Mechanism
    (pp. 37-43)

    And now there opens before us an exciting vista in which the automatic mechanisms of the brain interact with, and may be separated from, the brain’s machineryfor-the-mind.

    As I have pointed out, epileptic discharge may, and frequently does, confine itself selectively to one functional system, one functional mechanism within the brain. When it does so, it paralyzes that mechanism for any normal function. If the function of gray matter is highly complicated and only partially automatic, such as in the speech area of the human cerebral cortex, the epileptic discharge in it produces nothing more than paralytic silence, e.g., aphasia....

  16. 11. Centrencephalic Integration and Coordination
    (pp. 44-45)

    These two units: (1) the mechanism, the action of which is essential to the existence of consciousness; and (2) the mechanism of sensory-motor coordination, may be said to constitute the central integrating system. In their combined action they make sensory input available and motor output purposeful. They constitute a centrencephalic integrating system that unites functionally the diencephalon (higher brain-stem) with the cortex of both hemispheres. To this integrating system, sensory impressions come, and in its action, thought, and behavior find expression.

    But what a difference there is between the outward evidence of epileptic discharge within the mind-mechanism and that in...

  17. 12. The Highest Brain-Mechanism
    (pp. 46-48)

    What has been said about epileptic automatism throws much light on what must be happening in the normal routine of our lives. By taking thought, the mind considers the future and gives short-term direction to the sensory-motor automatic mechanism. But the mind, I surmise, can give direction only through the mind’s brain-mechanism. It is all very much like programming a private computer. The program comes to an electrical computer from without. The same is true of each biological computer. Purpose comes to it from outside its own mechanism. This suggests that the mind must have a supply of energy available...

  18. 13. The Stream of Consciousness
    (pp. 49-50)

    The material used by William James in his reasoning was psychological or philosophical, rather than neurophysiological. The “stream of consciousness,” he said, “is a river, forever flowing through a man’s conscious waking hours.”*This metaphor may be confusing. A river of water cannot be altered by the man on the bank. But thought and reason and curiosity do cause the stream of consciousness to alter its course and even change its content completely. The biological stream that is hidden away in each of us follows the command of the observer on the bank. A stream it is, and it flows...

  19. 14. Introspection by Patient and Surgeon
    (pp. 51-54)

    In my approach to this argument I have made no reference to introspection. Instead, I have depended on neurophysiological evidence and have made special use of the evidence available after a long experience with epileptic seizures. Trying to be objective, a scientist should not trust his own introspection too far. But it might give the reader another point of view, to listen to the introspective thinking of a highly intelligent patient as it came to me while I was “tinkering” with one of his brain mechanisms. I have published the case of the patient c.h. elsewhere,*but I shall refer...

  20. 15. Doubling of Awareness
    (pp. 55-56)

    Consider the point of view of the patient when the surgeon’s electrode, placed on the interpretive cortex, summons the replay of past experience. The stream of consciousness is suddenly doubled for him. He is aware of what is going on in the operating room as well as the “flashback” from the past. He can discuss with the surgeon the meaning of both streams.

    The patient’s mind, which is considering the situation in such an aloof and critical manner, can only be something quite apart from neuronal reflex action. It is noteworthy that two streams of consciousness are flowing, the one...

  21. 16. Brain as Computer, Mind as Programmer
    (pp. 57-59)

    Now let me climb down from the dizzy height of the hypothetical scaffolding that has been built about the brain. Consider with me the beginning of life, leaving aside, for the moment, the question of the essential nature of the mind.

    A baby brings with him into the world an active nervous system. He (or she) is already endowed with inborn reflexes that cause him to gasp and to cry aloud, and presently to search for the nipple, and to suck and swallow, and so set off a complicated succession of events within the body that will serve the purpose...

  22. 17. What the Automatic Mechanism Can Do
    (pp. 60-61)

    Inasmuch as the brain is a place for newly acquired automatic mechanisms, it is a computer. To be useful, any computer must be programmed and operated by an external agent. Suppose an individual decides to turn his attention to a certain matter. This decision, I suppose, is an act on the part of the mind. The brain response must be somewhat as follows: The highest brain-mechanism takes immediate executive action, which causes the sensory-motor mechanism to block, by inhibition, the inflow of information that isunrelatedto the subject of the mind’s new interest. At the same time, it allows...

  23. 18. Recapitulation
    (pp. 62-66)

    Mind, brain, and body make the man, and the man is capable of so much! He is capable of comprehension of the universe, dedication to the good of others, planned research, happiness, despair, and eventually, perhaps, even an understanding of himself. He can hardly be subdivided. Certainly, mind and brain carry on their functions normally as a unit.

    The neurophysiologist’s initial undertaking should be to try to explain the behavior of this being on the basis of neuronal mechanisms alone—this biped who falls on his knees to pray to his god and rises to his feet to lead an...

  24. 19. Relationship of Mind to Brain—A Case Example
    (pp. 67-72)

    Consciousness can be present whenever the highest brain-mechanism is normally active, even though adjacent parts of the brain are inactivated by some abnormal influence. A patient, whom I was called upon to see in Moscow under dramatic circumstances in 1962, illustrated the fact that conscious understanding may be present when motor control has been lost completely, or almost completely, and when the brain is not capable of making a permanent record of the stream of consciousness.

    The patient was the brilliant physicist, Lev Landau. Only intensive nursing had kept him alive during six weeks of complete unconsciousness following a head...

  25. 20. Man’s Being—A Choice Between Two Explanations
    (pp. 73-82)

    Sherrington concluded: “That our being should consist of two fundamental elements offers, I suppose, no greater inherent improbability than that it should rest on one only.”

    The challenge that comes to every neurophysiologist is to explain in terms of brain mechanisms all that men have come to consider the work of the mind, if he can. And this he must undertake freely, without philosophical or religious bias. If he does not succeed in his explanation, using proven facts and reasonable hypotheses, the time should come, as it has to me, to consider other possible explanations. He must consider how the...

  26. 21. Comprehensibility
    (pp. 83-90)

    A century of scientific progress has passed since Hughlings Jackson suggested that there were high levels of functional organization in the brain. He seemed to consider the highest as most closely related to the mind. Since his time, various partially independent mechanisms have been identified and mapped in the cerebral cortex and the higher brain-stem. None of them can explain the mind. The mind remains a mystery.

    I have told the story here of the progress of one pilgrim as he stumbled, sometimes blindly but always hopefully, toward a clearer understanding of what seemed to be the physical basis of...

  27. Reflections
    (pp. 91-101)
    Charles Symonds
  28. Afterthoughts by the Author
    (pp. 102-115)
  29. Bibliography
    (pp. 116-118)
  30. Index
    (pp. 119-123)
  31. Back Matter
    (pp. 124-124)