Sunday, November 13, 2005

"Who Are We?"

So is titled Chapter 12 of Dorion Sagan's and John Skoyles' excellent book, Up From Dragons: The Evolution of Human Intelligence. What a read.

This chapter in particular deserves careful reading from physiotherapists, in my opinion. I plan to bring it here in proper quotes, in dribs and drabs, footnotes inserted for the benefit of any who would want to look up originals...

Why do I think we should read it carefully? Because it brings together a great many threads that pertain to our work. It discusses movement, the brain's sense of an "I" or a "me", consciousness, where "will" and "volition" might be found (nowhere especially), how our environment is an extension of ourselves, how we extend ourselves (our consciousness) into our environment, our social extensions and our physical extensions, phantom limbs and other bits, our sense of embodiment and control, of efficacy, of self. It has everything to do with what we do, what we consider our profession to be experts in assisting people with. Yet, as I read this chapter I felt the ground move under my mental feet, like a mental earthquake, as I realized most of what we think we "know" is based on .. well, not a lot. Nothing in depth.

I offer it up as food for thought. And so we begin:

Chapter 12: What are we? p. 159

It is all odd and not a little unbelievable, the story of this book. Here we all are, touching physical things, the pages of this book or the seats we are sitting on. Scientists tell us that although we feel solid, we are in fact made of trillions of atoms. They tell us also that we live on a spinning planet, not the static flat world we see with our eyes. Your body, they go on, is not the flesh you feel with your hands but is made up of trillions of cells, each of which holds strands of information, DNA, the blueprints of your life. And further, in your skull there exist 100 billion (10 to the 11) cells intricately wired together – your brain. All this is overwhelming; nothing you intuit about yourself or the world is true. But perhaps nothing is so bold and beyond belief as the idea that that brain feels this astonishment! How can your consciousness be made of matter?

It is a problem as hard to pin down as it is to answer. Here are a couple of quotations to hint at it, the first from Massachusetts Institute of Technology computer guru Marvin Minsky: “There’s something queer about describing consciousness: whatever people mean to say, they just can’t seem to make it clear. It’s not like feeling confused or ignorant. Instead we feel we know what’s going on but can’t describe it properly. How could anything seem so close, yet always keep beyond reach?” (Minsky 1987: 151).

The philosopher Daniel Dennett says that it “is both the most obvious and the most mysterious feature of our minds. On the one hand, what could be more certain or manifest to each of us that that he or she is a subject of experience, an enjoyer of perceptions and sensations, a sufferer of pain, an entertainer of ideas, and a conscious deliberator? N the other hand, what in the world can consciousness be?” (Dennett 1987:160).

Hold your braincase and dip your fingers into it again in your imagination. Fondle your neocortex and do some wondering. Go touch your anterior cingulate, palpate your hippocampus, and tickle your frontal lobes. And ask yourself: What do these neural organs have to do with this feel, so immediate, intangible, and elusive of being “me” and alive? How could science make physical this incessant feeling that we are not physical but quite the opposite, something that is definitely not part of the material world? There seems to be an unbridgeable gap between the physical and what it is to experience consciousness – not just on first sight, but however deeply we think about it. All there is in the brain are neurons, plus the information their synapses store, plus the totality of their neural network interactions. How could anything mental arise out of them? Science might find the most extraordinary things, but it cannot discover magic, not even “neuromagic.” The alchemists tried to turn base lead into gold. Are we not seeking to do something similar: turn matter into mind? And even if this is possible, what kind of theory could imaginably let us understand and explain it?

The earlier chapters of this book were not written with the intention of giving an answer to this question. We have sought to understand our origins, not the fact that we are conscious. Indeed, we would rather not write this chapter and so enter the heated fray about this, the biggest question about the mind. But there is a temptation to go beyond looking at the workings and odyssey of the mind to examine this link. To omit it would, in any case, leave these chapters devoid of something. And like it or not we have, without seeking to, begun to offer a hint of an answer.

What are all these mindmakers, these parts of the brain, discussed in previous chapters? Let us look at them again, in terms not of what they do but of how they add to consciousness. Alone, none of them seems to us to satisfy the notion of “mind” or “brain.” All stand instead, in some way, partway between the mental and the physical. The activities of the mindmakers are more essential to our feeling of self than other, more familiar brain-directed skills such as sight, hearing, and the ability to move; we may be born (or become) blind, deaf, or handicapped but still feel fully ourselves. Mindmakers give us an intimate sense of who we are. Indeed they are so fundamental that we are not ordinarily conscious of the gruntwork they do in maintaining our feeling of self.

The unified mind – our sense of self – is, we believe, most likely an artifact or illusion, the seemingly singular result of what are in fact multiple underlying processes. Consider the sight-brain link. It takes up to 32 different areas in each cerebral hemisphere somehow working together to produce what we experience as sight. However far apart they are in the brain, we experience vision as a unified phenomenon. The same is true of the seven maps of our body’s sensations; we experience those seven homunculi not as seven bodies but as one. This suggests something quite profound. However much the functions of our brain are parceled out, the experience they give us still has a sense of coherence. The mind, we suggest, is experienced likewise. As with vision, it is not quite the unity of experience that we imagine it to be; under it lie many different mindmakers in numerous areas spread throughout our brain. Individually, they do not make our mind, any more than those individual areas of vision can create our experience of sight on their own. But collectively they may. Together they create the feeling that Minsky and Dennett observe as so indescribable and difficult to pin down.

More mindmakers await discovery. Some parts of our brain have been named – such as the claustrum (found below the temporal lobe) and habenula (on the inner side of the thalamus) – but we have few hints of what they do. And there are other uncharted territories. Deep in our brainstem are groups of neurons with odd names: nucleus basilis of Meynert (“Meynert’s base nut”), locus ceruleus (“blue place”), raphe nucleus (“seam nut”), and ventral tegmental area (“belly covering area”). These areas send axons up into our cortex, which secretes neuromodulators – brain chemicals affecting how neurons fire. The names of these chemicals are nearly household words from books on psychiatry and psychoactive drugs – acetylcholine, norepinephrine, serotonin, and dopamine. Even if you do not know their names, you have surely heard of the drugs that mimic them or stimulate their production: nicotine (acetylcholine), beta-blockers (norepinephrine), LSD (serotonin), Prozac (serotonin), ecstasy (serotonin), cocaine (norepinephrine, dopamine), and amphetamine (dopamine). They obviously touch the very essence of what underlies experience. All these aspects of our brain may therefore be key to who we are, yet we cannot quite grasp in what ways. Fortunately, our brain is an area where science is making rapid advances. In future years our understanding of its unknown parts and its neuromodulators will no doubt sharpen, but there will be a wait. Until we have developed the generation after next of brain scanners (and perhaps even the generation after that), what we do not know will vastly outweigh what we do. At present, all we can do is stretch our imaginations in considering what hides within our skulls. We are as people were at the beginning of the sixteenth century with regard to the physical world. The New World had just been discovered. The map of Africa showed little more than a rim of a coastline. Australia, Antarctica, and the vastness of the Pacific Ocean might as well have been on a different planet. The full exploration of the globe was to stretch centuries into the future. Now we are in the same position with regard to our minds: We have begun to see the outlines of the vast continent, the slippery and fascinating and wildly inhabited mindscape beneath our skulls.

The best place to start investigating consciousness is with our bodies. If nothing else, each of us has a body (Cotterill 1998). We feel our emotions in our bodies. Where do we feel sick or disgusted? Usually in our stomachs. Fear is felt as a bodily freeze rather than as a mental thought. It hits us where we act. If we do anything, it is our bodies that do it. Minds by themselves never do anything physical – telekinesis has never been shown to exist. However, every minute of our lives our brains move and do things with their – our – hands and feet. Without our bodies we cannot live. They are yoked to our minds as constant companions, continuous with us from birth to death. Our names may change, we may move, lose our closest friends, and replace our lovers. But our bodies never leave us. No one can divorce them. They do not mysteriously and disloyally leave us only to unexpectedly return. Nor are they like cars that we can sell, borrow, exchange, and then leave in the scrap yard. However much we may daydream about it, we cannot hire for a few days, to try out as our own, the body of Arnold Schwarzenegger or this year’s supermodel. Body swapping is out. Even if our consciousness is lost during sleep or when we are anesthetized, our bodies remain much the same. You will never wake up with the body of someone else. It is one fear we never entertain.

But there’s a problem. We are not our bodies. Remember leaving the dentist with an odd feeling in your mouth after you had a local anesthetic for a filling? Perhaps you never thought much about it, but your mouth’s numbness presents a minor brain puzzle. For a start, what could be more real and part of you than the feel of a slightly bloated and tingling cheek and gums? It is a feeing of “me-ness” – though a little odd – in your mouth. For a short time the local anesthetic stops input into your brain that comes from the nerves of your teeth and mouth. But that means your brain is not experiencing that area of your mouth, as its nerves have been knocked out by the local anesthetic. But if your brain is not receiving inputs from it, what are you feeling? Nothing? But what you are feeling is something. Oddly, what you are experiencing is a phantom, a neural extension of feeling (Patrick Wall, personal communication; Melzack 1992: 91, 95). It is usually a short-lived inconvenience, but many people suffer persistent phantoms after a dramatic life event.

Following an amputation, “the patient often wakes up from the anesthesia and asks the nurse when he’s going to be operated on. On being told that his arm or his leg has already been removed he may not believe it until the covers are removed (Simmel 1956:640).” Input to the brain does not necessarily cease after nerve damage. Cut off a limb and you cut off the information that it once sent to the brain, but that does not end a sense of its existence. A leg or an arm that has been surgically removed still feels as if it extends from the remaining stump (Habel 1956; Melzack 1990; 1992; Mitchell 1872/1965; Riddich 1941; Simmel 1956). Sometimes the feeling is vague, but most often, in spite of some “tingling,” it still has the feel of the limb that is no more. Over the years this will change. At first a phantom leg feels as though it is made up of a foot and a knee positioned like a real foot and knee but with gaps – vacuums – between them. Gradually, the parts telescope together. Indeed, after many years the foot withdraws up into the stump (Simmel 1956: 643). (These perceptions are probably related to neural plasticity changes in the maps of these parts on the brain.) But in spite of these changes, the phantom still feels like “me.” Sometimes phantom limbs are felt as static extensions of “me,” and sometimes people, such as Paul Wittgenstein (the pianist mentioned in Chapter 3), sense that they are moveable. Phantoms happen in the brain. Remember motor alpha, or mu, activity? It disappears when people move their limbs, not only real ones but phantom ones as well (Gastaut, Naquet, Gastaut 1965). They do not need their bodies to be able to feel them, or at least their neurons do not.

Like a real limb, a phantom can feel that it is burning, excruciatingly and exhaustingly cramped, or in other ways severely painful. But unlike pain in a real limb, it is unhealing pain. Worse, it is a hidden suffering. It is easy to get sympathy for a burned limb, which is visible, but not for pain in a limb that no longer exists except in one’s mind. Its pain is often related to the time of loss, as is the position in which it is experienced. A soldier, for instance, might feel his hand holding the bomb just prior to the moment that it exploded prematurely (Riddoch 1941: 203). A phantom may also perpetuate the more mundane sensations of the former limb. A person may still feel an old bunion; as one reported to his doctor, “I feel the ring on the finger that isn’t there (Habel 1956: 632).” Others feel watches keeping time on wrists that are no longer there.

It isn’t just legs and arms that become phantoms but also noses, tongues, and breasts. One in four women experience the phenomenon after a mastectomy (Aglioti, Cortese and Franchini 1994; Melzack 1990: 89). The nineteenth-century neurologist Weir Mitchell noted briefly the report of a case of a phantom penis that sometimes became “erect (Riddoch 1941: 207; Hanowell, Kennedy 1979; Mitchell 1872/1965: 350; Melzack 1990:89; Fisher 1999).” Some people with severed spinal cords report orgasms, during dreams, in sexual organs no longer linked to their brains (Money 1960).

You do not need to lose part of your body to experience phantoms. Have an accident that breaks your spine, and you will most likely be quadriplegic for the rest of your life. Not only will you be paralyzed in every limb, but your brain will be cut off from the sensations coming from them and from the rest of your body below the neck. Yet your sense of your body will not go away. In place of your limbs, you may feel phantoms of them as they were just at the moment when your spine was injured. The paper (Ettlin, Seiler, Kaeser 1980) from which we obtained these details contains illustrations of people’s accidents and the positions they now feel their phantom limbs to be in. A person thrown by a bull feels that his legs are forever splayed above his head. People sitting with crossed legs just before their car turned over feel that they remain so. Their embodiment has come apart from their still-surviving bodies. Curiously, if a person was unconscious at the time when his or her spine was broken, no phantoms arise and they lose any sense of existing below the neck. Instead of having a phantom body, they feel that they exist bodilessly, as only a head and shoulders.

This is all rather mysterious and shocking, a side of surviving accidents many would prefer not to know about. But it is overwhelming evidence that our brains invent the sense that our bodies are real and with it the surety that “we” are real. We know they do this because there can be a separation – as with phantom limbs – from actual physical embodiment. Our everyday experience is thus wrong: Our sense of being a body does not rise directly from our physical self but from our neurons. It is a conclusion with profound consequences for how we understand the nature of the relationship between our brain and our experience.

If you doubt that the brain creates the illusion of physical embodiment, then consider the following. It is a phantom movement illusion discovered by Vehe Amassian of the State University of New York (SUNY) (Amassian, Cracco, Maccabee 1989). Amassian stimulated his motor cortex with rapidly alternating magnetic fields. This triggered it into sending two sets of signals, one to make a motor movement and another – to the parietal cortex – to tell it the fingers were about to move. He then cut off inputs to and outputs from his hand using a tourniquet on his arm, so that his hand went numb. The signal triggered in his brain was thus unable to produce any body movement, and the brain could not tell whether any had been made (at least by feel). But the motor cortex had also sent signals to the parietal cortex to tell this part of the brain that the hand and fingers were about to move. Now, if our sense of existing is purely neural, then Amassian should have felt movements in his fingers. Indeed, he (and various others who have gone through this unpleasant procedure) did feel his fingers move when the magnetic fields were applied, but if he had looked, he would have seen that they had not. Thus, whatever happens to our bodies afterward, it is the initial transmissions in the brain that gives rise to a feel of “me.”
I will eventually bring the entire chapter here, and will add thoughts as they come up. For now, I think it is best to simply contemplate the matter. In digestible chunks.

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