Saturday, January 01, 2005

The Deceptive World of Subjective Awareness Part 1

Mind Time: The Temporal Factor in Consciousness

By: Ian H. Robertson Ph.D.

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Mind Time: The Temporal Factor in Consciousness

By Benjamin Libet

 

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Wider than the Sky: The Phenomenal Gift of Consciousness

by Gerald M. Edelman

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A Brief Tour of Human Consciousness: From Impostor Poodles to Purple Numbers

By V. S. Ramachandran

The phone woke me at three in the morning. It was my mother: 

“Please tell your father that he is in his own house.”

Dad came on the line, lucid and alert. I asked him what was wrong.

“We have to get out of here before the people come back.”

“What people, Dad?”

“The people whose house this is.”

“But it’s your house, Dad.”

“Oh, no, son, it’s not.” His tone of voice was patronizing and slightly irritated.

“It is, Dad—I lived there since I was a baby—the tree outside is the same age as me.” 

The conversation went on. In the end, he agreed to stay in the house, but it was clear that he was indulging me, agreeing to stay in someone else’s house to keep me quiet. He was convinced that we were all being fooled and that he was right. 

Later on, he would let slip his belief that my mother too had been replaced, looking across at her and referring to “the real Mum, not that one.” But he was a tender man and tried not to hurt us with his knowledge of the truth. Only now have I begun to realize that, for the past two years of his life, I too was almost certainly not “the real Ian.” My father had suffered a hemorrhagic stroke to the right basal ganglia of his brain and was suffering from Capgras syndrome—the belief that familiar people and, in his case, also places have been replaced by identical-looking impostors. 

Throughout his gradual decline over the next year after the call, I always wondered what his world felt like. Did he feel like someone who had been transported to another planet, surrounded by people and places that looked like those he had been familiar with but which were totally strange and unfamiliar? 

I once phoned him when he was briefly alone at home.

“Ian, you know that sometimes when people have phoned, I think that they have been here.” Then he paused, as if bracing himself to ask something it was hard to articulate. “Ian, is my mother still alive?” 

“Dad, you are 90, she died 30 years ago.” 

“And my father?” 

“I’m afraid not, Dad.”

“Good God,” he replied. 

The miraculousness of consciousness is nowhere more poignantly revealed than when it fractures.           

One of my patients—let’s call him Chris—was a young man who suffered a severe head injury in a motorcycle accident. When I met him, almost a year after the accident, he believed—literally not metaphorically—that he was dead. He was afflicted with Cotard’s syndrome. So utterly strange was the planet that he inhabited since waking from his coma that he could come to no other conclusion than that he had died. This was less an intellectual conclusion than a gut feeling. 

He described to me how, after discharge from the hospital, his mother had taken him to a tropical resort to recuperate. He described the blue water of the pool, the hot sun, and the beautiful women and said, “I knew I was in heaven.” This was not said with a smile. This intelligent man, a former banker, could not have been more serious. 

The conscious world of our subjective awareness is one of complete isolation. No one else can know what it feels like to be me, whether my experience of “blue” is remotely like your experience of “blue.” The mystery of consciousness is perhaps the greatest puzzle in the universe. 

Take a moment to do the following. Put down the journal. Lay your right hand on your knee or on a table. Let it rest there for any length of time. Then at some point determined only by you, flex your wrist and raise your hand. 

Now reflect on what went on in your mind as you did this. Did this feel like a voluntary act of your unique free will? I just did it, and it did feel like I decided and moved. Yet I was deceived, and so were you. 

SEEKING A CONSCIOUS MENTAL FIELD

I know we were deceived because of the meticulous studies of awareness carried out by Benjamin Libet, Ph.D., a physiologist who pioneered the experimental investigation of consciousness, initiation of action, and free will. He describes these studies in his intriguing and carefully argued new book Mind Time: The Temporal Factor in Consciousness. 

Libet used a simple but ingenious experimental design to measure when people have the first awareness of their intention to move their hand in the way you just did. He found that up to half a second before you become aware of the intention to move your hand, the brain has already generated the preparation to move in the form of an electrophysiologically measured “readiness potential.” 

A meticulous experimentalist and an excellent scientist, Libet convincingly wards off the many different potential alternative explanations for this profound discovery. Yet, he does not conclude that this shows free will to be an illusion; he argues that what is under our conscious control is the power to veto our unconsciously generated acts. His evidence for this is weak, however. Its basis is that conscious awareness of the intention to move arises around 150 thousandths of a second before the actual movement (and roughly half a second after the first brain activity controlling the movement). Libet also shows that we become consciously aware of a stimulus only after it has activated the appropriate neurons for about half a second. It is as if our conscious awareness is running half a second behind the events of which it is becoming aware. 

Is then my consciousness in reality as fractured as was my father’s? Clearly, I am deluded in believing that I consciously decided to move my wrist when I did. In what other respect is my consciousness not as it appears to me?

How does the categorically different nonphysical phenomenon of subjective experience, of conscious awareness, come from the physical activities of nerve cells? 

This is an important question because of the “hard problem” posed by philosopher David Chalmers, Ph.D., namely: How does the categorically different nonphysical phenomenon of subjective experience, of conscious awareness, come from the physical activities of nerve cells? 

This problem is one of the biggest for theoretical physicists striving to find the “theory of everything,” as well as for neuroscientists, philosophers, and anyone seeking to understand consciousness. There are three basic responses to this problem. First, the simple Cartesian dualist position says consciousness can exist without brain activity. The second is the so-called “identity theory” first proposed by the philosopher Benedict Spinoza that thoughts and experiences are always identical with a sequence of objective changes in the brain and body. The third main position is that mental states do not actually exist and that the mind is a myth tricked into believing in its own relevance. This would be, roughly speaking, the “eliminative materialism” view of philosophers Paul Churchland, Ph.D., and Patricia Churchland, Ph.D. 

Libet subscribes to none of these basic positions. Instead, he proposes that consciousness is a high-order property emerging from the activity of billions of brain cells, just as the solvent properties of benzene arise from the particular arrangement of carbon and hydrogen atoms of the benzene ring. But, unlike physical emergent properties, the emergent subjective experience is not directly observable or measurable by any physical means. Libet argues this subjective experience exhibits unique characteristics. One such characteristic is that free will (using only its power of veto, not of initiation) can influence brain activity without itself being based in a corresponding brain activity. 

The crux of this is Libet’s hypothesized existence of what he calls a “conscious mental field.” He maintains this field probably cannot exist without some brain activity but otherwise has a semi-independent existence that can influence brain activity and behavior. As an inveterate and courageous scientist, Libet even describes the experiment that would have to be carried out to test this. 

For this experiment, one would need to find or create an isolated but living slab of cortex. Such isolation could be done chemically or surgically, and Libet goes into great details about the pros and cons of different surgical and chemical techniques. He believes that there could be 5 or 10 people worldwide—for instance, with a specific epileptic focus in a primary sensory area—who are potential candidates for his remarkable experiment, and he is scouring the world for a compliant neurosurgeon to conduct it. The goal is to find out whether the patient would have a conscious experience if this isolated slab of tissue were stimulated. If so (and assuming the necessary alternative explanations could be ruled out), then this would be a discovery as profound as the theory of relativity or the establishment of the double helix structure of DNA as it would prove the existence of a totally new phenomenon in the universe that is irreducible to the known components of matter—namely, the conscious mental field. 

“For any idea that does not appear as bizarre at first, there is no hope,” Libet quotes in support of his extraordinary hypothesis. 

Libet hypothesizes this conscious mental field is the source only of conscious subjective experience and not of all the other information processing and storage capacities of the brain, which take their physical form in the tissue. It is the source of a veto-wielding free will and is, for example, the substrate of my personal experience of watching a wave breaking against a rising sun. “For any idea that does not appear as bizarre at first, there is no hope,” Libet quotes in support of his extraordinary hypothesis. Most biologists would be impatient with such an apparently unparsimonious hypothesis, but no doubt Newton would have been equally impatient with the notion that his apple was falling down a slope in the space-time continuum.

A PROCESS, NOT A THING

To Gerald Edelman, M.D., Ph.D., 1972 Nobel Prize winner for immunology who has become a neuroscientist, consciousness is a process or a relationship, not a thing. As such, it simply cannot cause any physical process, including neural activity in the brain. Such is the view he proposes in his book Wider than the Sky: The Phenomenal Gift of Consciousness. 

That our distinct first-person subjective experiences—what philosophers call “qualia” —have none of the properties of the neural activity that underlies them is not the problem for Edelman that it is for Libet. Because consciousness is a process for Edelman, it need not resemble the properties of the dynamic structure underpinning it, any more than an explosion need resemble the explosive. Neither is the issue of subjectivity—the impenetrability of my consciousness with yours—a problem. Consciousness as a process is tied to a particular body and brain with a unique history. Consequently, from an outside point of view, “the first-person experience is not written in transferable currency that is completely negotiable by a third-person scientific observer.” 

In Edelman’s view, the process of consciousness arises from the synchronized reverberations of interconnected sets of neurons, particularly between the thalamus and cortex. His experimental test of this process was to study the brain’s activity when a person was aware of stimuli that the brain could be shown to process unconsciously, compared with when the person was unaware of them. For example, your brain can respond to scenes that you have seen before even though you have no awareness of having seen them. He discovered that awareness was associated with a much higher level of coordinated back and forth firing of large groups of neurons in widely dispersed areas of the brain. This back and forth, or re-entry, phenomenon is at the heart of conscious experience, argues Edelman: consciousness is a process arising from the discriminations leading to perceptions that we make in the sensory world, and these discriminations have their physical basis in the firing of neurons. 

Although Edelman says both animals and humans have a primary consciousness, only human beings have higher-order consciousness, a key feature of which is being conscious of being conscious. 

Although Edelman says both animals and humans have a primary consciousness, only human beings have higher-order consciousness, a key feature of which is being conscious of being conscious. The language systems that are unique to humans allow us to explicitly remember the past and imagine the future, so we escape the eternal present of primary consciousness and move into the joys and terrors of a self extended in time. 

Edelman deals cursorily with Libet’s delayed awareness data by saying that consciousness is not involved in automatic motor processes but instead is related to the planning and creation of new combinations of already automatic routines. Presumably he would argue that such conscious activity would be synchronous with the underlying neural activity, not either before or after it. 

If consciousness cannot be causative, are we then zombies, in Edelman’s scheme of things? No, because, in his view, the basis of consciousness is the distinctions we make in the perceived world. The back and forward reverberations between different brain regions allow a distinction to be made, while the subjective conscious experience is the distinction. 

So when I look out my window and see a patch of blue sky between bulbous Irish clouds, my subjective experience of “blue” is the distinction that my visual cortex allows me to make. I cannot be certain that this experience of “blue” is anything like yours, but it is a fair bet, because of our similar evolutionary histories, that it is not too different. On the other hand, “blue” has a whole series of associations and experiences behind it in my own personal body and brain history that yours does not, so I should not necessarily expect that my experience is identical to yours. 

CONSCIOUSNESS AS AN UNRELIABLE MARKER

V. S. Ramachandran, M.D., Ph.D., is a brilliant and creative neurologist who has intrigued laymen and scientists alike with his accounts of disturbances of consciousness like those that my father and my patient Chris showed. The collection of his BBC Reith Lectures, A Brief Tour of Human Consciousness: From Impostor Poodles to Purple Numbers, flows in his exuberant style, with intriguing hypotheses-to-die-for strewn about the text.

Try this experiment inspired by Ramachandran’s work that one of my students, Mary Clarke, and I devised. Prop a mirror on a table, facing to the right at roughly right angles to your body as you sit at the table. Put your right hand flat on the table and angle the mirror so that you can see your right hand reflected in the mirror without craning your head. Pull your chair well in under the table, and now put your left hand flat on your left knee under the table so that it is roughly in line with your right hand, albeit at a lower level. Now, while looking at the reflection of your right hand in the mirror, clench and unclench both hands in a regular, comfortable rhythm every one or two seconds. Do this for two or three minutes, or until you notice something. I will return later to what you might observe. 

When I was in clinical practice, I was testing one of my patients, Peter, who suffered from a failure to be aware of things on the left side of space, which is called left hemispatial neglect. His left arm was paralyzed, and, as he carried out one of my tests, he said something that I didn’t make out about his arm getting in the way. I asked him to repeat what he had said, and he mentioned “my other arm.” “What other arm?” I asked. “This third one,” he said, nodding to his left. I talked to him for a long time, trying to work out what he was experiencing. Finally, I asked him to lift his third arm and point to the corner of the room. He did so, appearing to exert some effort, and held it there. “Are you still pointing,” I asked him, as he sat, his left arm flaccid on his knee, and he said “Yes, still pointing.” This man was well-oriented, not confused, and was able to hold a lucid and intelligent conversation. Yet, he was firmly convinced that he had three arms. 

If you tried out the mirror task, did you notice anything? If you managed to follow my instructions, you should have had quite a strong sensation that your left arm was in a different place than it actually was— namely, on the table on the other side of the mirror from your right arm. In a sense, therefore, you had three arms, just like my patient. 

Consciousness may feel integrated and unitary, but that does not make it a reliable marker of objective reality. If you did the experiment, you saw that it can be compelling, unitary, involuntary…and wrong. So it was for my Dad and for Chris. My father’s house and family were replaced by identical-looking impostors, and Chris was dead, while at the same time he was walking and talking. 

It is difficult to resist the sensation that your arm has moved in the mirror experiment, although Mary Clarke and I showed that you can modify it to some extent by attending in particular ways. There is a compelling subjectivity to the phenomenon that is completely resistant to rationalization and logic. I believe that my father and Chris had an equally compelling subjective experience that also resisted logical refutation. It is a wonder that Dad indulged me as he did when he agreed to stay in this stranger’s home—no wonder he gave that knowing and resigned laugh as he hung up. 

Pure identification is not enough to guide our response to what we see... If you met a lion and responded, “Oh, I recognize that; it’s a lion,” you would be dead very quickly. What you need quickly is an emotional evaluation of what you have identified, one that has you panting and incontinent up a tree by the time you have even articulated the word “lion.” 

Ramachandran gives a lucid hypothetical account of how Capgras syndrome, such as my father experienced, can arise. The image that is my mother’s face is analyzed in more than 30 different visual areas, with its identification finally occurring in a region called the fusiform gyrus. If the stroke had affected this part of my father’s brain, he could well have had the quite different problem of not recognizing my mother’s face, while still being able to recognize her voice and respond normally to it. This disorder is called prosopagnosia. My mother was, however, being correctly identified in his brain in that she looked identical to the cluster of memories and knowledge associated with the woman he had lived with for 52 years. But pure identification is not enough to guide our response to what we see. If you met a lion and responded, “Oh, I recognize that; it’s a lion,” you would be dead very quickly. What you need quickly is an emotional evaluation of what you have identified, one that has you panting and incontinent up a tree by the time you have even articulated the word “lion.” 

This emotional evaluation arises from ancient pathways between visual centers in the brain and the emotional centers in the limbic system, particularly the amygdala. Ramachandran suggests that Capgras syndrome can arise when the pathways between the visual areas and the amygdala are severed. My father, in other words, recognized the appearance of my mother but failed to have the positive emotional reaction to her face that would indicate familiarity. He concluded, therefore, that while she looked identical, it was not she. For Chris, things were even worse; all of his sensory areas were disconnected from the amygdala, and so everything looked identical yet at the same time uncannily strange. His bleak but inescapable conclusion was that he was dead. 

FREE WILL AND OUR SENSE OF SELF

Most of Ramachandran’s book is the highly accessible text of his BBC lectures in which he outlines the quirks and vagaries of consciousness such as are apparent in Capgras and Cotard’s syndromes. But in his last chapter “Neuroscience: the New Philosophy,” he tackles some of the more fundamental problems raised by Edelman and Libet.

Ramachandran proposes an experiment to follow up on Libet’s discovery that your brain prepares for a supposedly freewill-driven move of your finger half a second before you consciously decide to move it. Suppose I measure your brain activity and flash a message on a screen the moment your brain’s preparation to move begins, he asks. How would your experience of moving your finger change? 

You suddenly might feel that the machine is controlling you, that you are a mere puppet, and that free will is an illusion. You might even feel a bit paranoid as a result, like schizophrenics who feel that their actions are controlled by external forces. Alternatively, you might think that the information about your brain’s activity does not change your sense of free will, preferring to believe that the machine has some precognitive abilities that enable it to predict the movements that you nevertheless control perfectly. Finally, you might “confabulate”—make things up—clinging to your sense of freedom by mentally rearranging the order of events. For example, you might deny the evidence of your eyes and insist that your sensation of will preceded the machine’s signal. 

It is not yet technically feasible to measure single events in the brain in this way, so this experiment must wait, but the results of it will be as fascinating as those of the many other intriguing experiments that Ramachandran conducted in his career. Ramachandran speculates, however, that evolutionary selection has ensured that the subjective sense of willing the movement is delayed to coincide with the actual movement, rather than with the onset of the brain processes that underlie it. This suggests that subjective sensation of willing must have some evolutionary purpose—but what purpose could that be other than moving the finger? “Perhaps our very notion of causation requires a radical revision… as happened in quantum physics,” Ramachandran speculates. 

Ramachandran also gives one of the most interesting analyses of the concept of “self” that I have read. To him, “awareness” simply does not mean anything without an awareness of awareness and a concomitant sense of self. 

This is dangerous territory indeed from Edelman’s perspective, although both Libet’s and Ramachandran’s actual and thought experiments burrow much deeper into Chalmer’s “hard problem” than does Edelman’s. Ramachandran also gives one of the most interesting analyses of the concept of “self” that I have read. To him, “awareness” simply does not mean anything without an awareness of awareness and a concomitant sense of self. If you are not aware that you are aware, then by definition you are not aware. Ramachandran thus rules out Edelman’s primary consciousness as being true awareness and presumably increases the theoretical gap between man and other beasts. 

“Self” has five characteristics, he argues:

  • a sense of continuity, an unbroken subjective thread linking past, present and future;
  • a feeling of unity and coherence of the self—we each feel like one person;
  • a sense of location in a body;
  • a sense of agency—of being in charge of our own actions and destinies; and
  • a sense of awareness of being aware. 

Ramachandran hypothesizes that these five attributes of self are based in different brain regions, and that damage to different areas will produce different disorders in awareness and sense of selfhood of the kind that Chris, Peter, and my father showed. 

So if the self is so fragmented, why does it—and its companion consciousness—feel so unified? Perhaps it is logically impossible to experience more than one self, because this would raise the question of who or what is experiencing the two selves. Furthermore, our sense of self can be largely a construction of our interactions with other people, as philosopher George Herbert Mead originally proposed. 

Ramachandran suggests that fundamental to integrating these various aspects of self is the operation in the frontal lobe of the brain of so-called “mirror neurons”— neurons that fire not only when one carries out an act, but also when one observes another person carrying out that act. These neurons might be the bridge that rescues us from the position that my historical ex-colleague, Bishop Berkeley of Trinity College Dublin, left us in. Crudely speaking, his view was that the only reality that we can be convinced of is that of our consciousness and we cannot be sure of the existence of the external world. Perhaps the existence of mirror neurons helps us escape from this lonely island of our own consciousness and links us to other minds. 

THE STILL UNSOLVED PROBLEM

Is consciousness no more than the explosion out of the brain’s explosive—a non-problematic emergent property of the trillion-fold connected brain tissue, as Edelman would argue? Or is it a fundamentally different phenomenon, a mental field that has its home in the tissue but can cause changes in that tissue, as Libet would argue? 

The puzzle of consciousness has not been solved by these three books, but after reading them we know somewhat more about how the inner working of the mind links to the hard wiring of the brain. But the hard problem remains unsolved— how to understand how the sensation on my face of a shaft of warm sun that has just broken through the blue gap in the clouds can arise from the objective activity of my brain cells.

What I do know is that my own consciousness is not necessarily the confident, causal agent it feels like most of the time. Just as were my father and Chris, I am, in my own way, tricked—not least in believing that I intended this last word and caused my brain to write it

EXCERPT

From Mind Time: The Temporal Factor in Consciousness by Benjamin J. Libet. © 2004 by Benjamin J. Libet. Reprinted with permission of Harvard University Press.

HOW DO EMERGENT PHENOMENA RELATE TO THE PROBLEM? In the physical world we recognize that the phenomena displayed by a system may not be evident in the properties of the subunits that make up that system. For example, the compound benzene is composed of six carbon and six hydrogen atoms. Kekulé proposed that the six carbon atoms are connected in a ring structure, with the hydrogens bound to the ring at the six junctions between the six carbon atoms in the ring. This is the famous benzene ring fundamental to organic chemistry (and to biology). The properties exhibited by benzene (as an organic solvent and so on) could not have been predicted, a priori, from the properties of the carbon and hydrogen atoms themselves. That is, a new property emerged from the C6H6 ring system. Similarly, the properties of a wheel are not evident from the properties of the materials used to construct the wheel (as noted by Sperry, 1980). The wheel’s property of rolling emerges from the system created by the specific arrangement of the materials used to make the wheel. The appearance of a magnetic field around a wire that is conducting an electric current is also a phenomenon that emerges in that system. As the astrophysicist Sir Arthur Eddington once said, “We used to believe that if we knew one thing and then another, then we know two, because one and one are two. We are now discovering that we must learn more about the ‘and’ ” (quoted by B.D. Josephson, 1993). In other words, there are properties of systems that are not evident in its component parts. 

We are virtually forced to regard conscious subjective experience similarly, as a phenomenon that somehow emerges from an appropriate system of activities of the physical nerve cells in the brain. However, unlike physical emergent phenomena, the emergent subjective experience is not directly observable or measurable by any physical means, as subjective experience is only accessible to the individual having the experience. Clearly, the emergent subjective experience of this system is unlike the properties of the responsible nerve cells; it could not have been a predicted outcome of these neural activities. It should not be surprising that the emergent subjective experience exhibits unique unexpected characteristics. 

EXCERPT

From Wider than the Sky: The Phenomenal Gift of Consciousness by Gerald M. Edelman. © 2004 by Gerald M. Edelman. Reprinted with permission of Yale University Press.

I have stated in the Preface of this small book that my hope is to disenthrall those who believe that the subject of consciousness is exclusively metaphysical or necessarily mysterious. It is a Herculean task for consciousness studies to rid the stables of dualism, mysterianism, paranormal projections, and unnecessary appeals to as yet poorly characterized properties at different material scales— for example, quantum gravity. Some but not all of this task relates to the use of language. In this account, for example, I must answer to the accusation that I have submitted to the paradoxes of epiphenomenalism. This notion, a cousin of dualism and a prompting ground for “zombi-speak,” must be reexamined. I believe that the difficulties with this notion have arisen because of the failure to attend to the neural correlates of conscious properties. Inasmuch as the neural process C´ that entails consciousness C is causal and reliable, we do not find ourselves faced with a paradox. C´ underlies the ability to make distinctions in a complex domain, and C states, the properties entailed by C´, are those distinctions.

This relationship allows us to talk of C as if it is causal. For most situations, this is not dangerous, given the reliability of the relationship. Only when we are tempted to abrogate physics or give to C mystical powers is this procedure hazardous. The relation of entailment between C´ and C clarifies the issue and helps define qualia as higher-order discriminations with distinct and specific neural bases. A consciousness-free zombie, on these grounds, is logically impossible—if it had C´ processes they would necessarily entail C. Of course, I am aware of the fact that the clarification introduced by this analysis must be proven by actual experiments on the relation between C´ and C. But like the proportionality constant of mass in the equation F=mA and the assumption of the constancy of the velocity of light in a vacuum, the foregoing analysis promises a simplification and coordination of one of the most challenging problems of science.  

EXCERPT

From A Brief Tour of Human Consciousness: From Impostor Poodles to Purple Numbers by V.S. Ramachandran. © 2004 by V.S. Ramachandran. Reprinted with permission of Pi Press.

Free will—the capacity to plan open-ended scenarios and try out even improbable scenarios entirely in the mind by juggling images and symbols—if linked with episodic memories, enables you to see yourself as an active agent doing things in the future (or past), thereby generating a full-fledged sense of self. As a bonus, this ability would also enable you to present yourself to others as a predictable human being with certain stable attributes, an important capacity for intensely social creatures like us. By combining behavioral studies on patients with brain lesions—the main theme of my work—with functional brain imaging, and viewing the results from an evolutionary perspective, we can begin to elucidate these different components of self and finally tackle the mystery of how the components interact to generate awareness and self-consciousness. 

The widely used phrase “raw awareness of sensations,” or “primary awareness,” employed by my colleagues to designate an earlier phylogenetic stage, is an oxymoron. “Awareness” simply doesn’t mean anything without a metarepresentation—an awareness of awareness and a concomitant sense of self. If you are not aware that you are aware, then by definition, you are not aware! Humans are unique in this respect. The Victorian biologists Alfred Russel Wallace and Richard Owen were correct in asserting that a huge gap separates us mentally from other beasts. But, as I have suggested in this chapter contrary to Owen, what sets us apart from other mammals, including other primates, is not any single structure—such as the hippocampus minor—but a set of circuits that includes the temporo-parieto-occipital junction (especially the angular and supramarginal gyri), the Wernickes area (concerned with semantics) and the anterior cingulate with its limbic connections (“attention,” “will,” “desire,”) and the right parietal and insula (concerned with embodiment). These structures are for consciousness what chromosomes and DNA were for heredity. Know how they perform their individual operations, how they interact, and you will know what it means to be a conscious human being.



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Scientific Advisory Board
Joseph T. Coyle, M.D., Harvard Medical School
Kay Redfield Jamison, Ph.D., The Johns Hopkins University School of Medicine
Pierre J. Magistretti, M.D., Ph.D., University of Lausanne Medical School and Hospital
Robert Malenka, M.D., Ph.D., Stanford University School of Medicine
Bruce S. McEwen, Ph.D., The Rockefeller University
Donald Price, M.D., The Johns Hopkins University School of Medicine

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