A bit lengthy today, but juicy. Here is the last piece in Skoyles/Sagan's Up From Dragons chapter.
Inner MaestroSo much food for thought.
We have a world within that exists because our brain organizes its actions and thoughts with internal cues. Some philosophers, however, deny the existence of such an inner place. According to them, our inner feel is a “beetle hidden” in a box we cannot open and so is not meaningfully there. To them, to see consciousness and mind as things inside us is to see ghosts in a linguistic mirage generated by the misuse of words. Perhaps they are right within the context of their philosophical reasoning. But it would seem that they ignore the prefrontal cortex and its vibrant life of inner cues. Philosophers never see any need for the brain to make its actions and reactions independent of the outer world, for they imagine us to have mushy brains, not assertive ones with inner cues. They are the neuroscience equivalent of medieval scholar monks counting angels on neurons, blissfully ignoring twenty-first century science and its discovery of the subtle logic of our bio-computers.
As you think, recall, and imagine, you are, in a sense, your inner cues. They may not be the actions taken in the outer world, but it is through them that we act, if only in the inner world of our memories and imaginations. Perhaps the act and the actor are the same? If the brain can create an intensely “me” sense of embodiment in limbs that no longer exist, then what of mental actions orchestrated inside us? They may not offer us three- dimensional embodiment, but, as shown above, extension is not needed for the “me” feel of embodiment. What is needed is some control feedback relationship. And, as with social presence, the relationship need not be physical. It would seem that the inner cues guiding actions, recall, imagination, and thought are part of our sense of being a “me.” Here are a multitude of control and feedback processes and cues flipping motions, memories, images, and ideas in and out of existence.
There are in fact clues that the preparation done by our brains before we act is linked with consciousness. One thing prefrontal inner cues do is initiate thoughts and actions – we are anything but vegetables. We are constantly doing things, if not with our bodies then with our minds. But few actions and thoughts arise fully formed. Before we voluntarily take even the smallest action, our brains prepare.
Such preparations have different durations. Some, taking half a second or less., happen in the parts of our brain dealing with movement. Before we move, our motor cortex draws up programs as to how to act in a complex process that involves linking motor memories together into sequences, or motor programs. And few actions happen without feedback control: Ongoing sensitivity to feedback requires subtle preparation so that our actions can be integrated and so guided by sight and touch. This is all brain work, a labor done silently by our motor neurons in the half-second or so before we act. And it is not done alone. Overseeing this work, the anterior cingulated cortex attends to the consequences of our actions, focusing up to 2 seconds before we act. And before that, other neurons, in the prefrontal cortex, may start up one or many seconds earlier, depending upon the task (Singh, Knight 1990). They ask when and where the movement should start, and under what conditions. Is this the time to act? Such prefrontal preparations come not only before actions but before we reach a mental conclusion, or face an expected event or punishment. Our minds are always looking ahead and anticipating. There are whole families of processes being loosely summarized together here. But they share a brainwave “signature.” The details of how they do this are just being discovered. What we know is that before we act there is a general shift in the electrical activity of our brains. Temporally extended action requires the slow potentials described in Chapter 5 that are under the prefrontal cortex’s control (Brunia, Damen 1988; Rockstroh, Elbert, Birbaumer, Lutzenberger 1983; Rockstroh, Elbert, Canavan et al., 1990). They are also required for intentions that are never carried out, arising not only before we try to move but also when we seek to relax (Terada, Ikeda, Negamine, Shibasaki 1995). This is where our sense of willing things may come from. Involuntary actions – tics, for instance – are not preceded by such readiness potentials (Fahn 1993: 13).
A person senses the conscious decision to move his or her little finger about a third of a second after the onset of the motion’s readiness potential (Libet 1985). It is a negative potential linkd to the preparation made by our supplementary and other motor cortices before an action. It is hardly a major act of will, but it is an act of will nonetheless. But if the consciousness of making an act arises with the act itself, what of the other brain preparations? Do not the other potentials tied to our prefrontal cortex also give rise to a sense of consciousness as we think ahead and prepare – intend? After all, this part of us is focused on making and supervising the inner cues organizing our actions and thoughts. Scientists can see this on PET scans: Blood surges into part of the dorsolateral prefrontal cortex (Frith, Friston, Liddle, Frackowiak 1991; Jahanshahi, Jenkins, Brown et al., 1995). when people will actions- and only when they will them. This does not happen when our actions are guided from outside, such as when we copy movements. We do not “will” such actions.
Another possible link between consciousness and the focusing and willing of our brains is our gamma (40-Hz) oscillations (Sauve 1999). We experience our senses as a unity even tough the brain does not process them as such. That unity seems to come from the linking done by gamma. But gamma is not only found in our sensory cortices; it is also found when our prefrontal cortex guides our focusing on touch and when we prepare to do things (Desmedt, Tomberg 1994; Kristeva-Feige, Feige, Makeig et al., 1993; Murphy, Fetz 1992; Sanes, Donoghue 1993). In these cases, gamma, instead of joining our senses, binds the various processes that let us attend and do things. So gamma may unify not only perception but also our otherwise varied senses of doing – intention and will. Some evidence for this comes from anesthetics.
“The consciousness was terrifying… the… terror of trying to signal one’s conscious state to someone, but unable to even twitch a bloody eyelash” (Kulli, Koch, 1991: quote, 6). To wake up during an operation is a nightmare worse than any other. (Fortunately it is very rare; you are more likely not to awake at all after the operation.) But very, very exceptionally it does happen. Anesthesiologists seek to give us the lowest effective dose of an anesthetic, since the drugs can kill and the safe dose range is small. Once in awhile they are over cautious and underdose the patient. Added to some anesthetics are drugs to stop involuntary movements by the patient, which might cause problems for the surgeon. At too low a dose, these paralyzers may work but the anesthetic itself may not. It is a nightmare: paralysis and consciousness on the operating table. The anesthetist needs a way to know when a person becomes conscious even though paralyzed. The easy clues, such as heart rate and blood pressure, are not reliable. But one thing in our brains seems to be – gamma activity. The drugs that have been given the patient paralyze the body at the level of the muscles, but they don’t stop the initiation of thoughts in the brain. A person knowing that the surgeon is operating has a brain alive to that fact. The binding of its thoughts and experiences can be monitored. When gamma responses weaken and disappear, consciousness vanishes as well (Kulli, Koch, 1991; Plourde 1993; Schwender, Madler, Klasing et al., 1994).
All this adds up to a picture of gamma’s linking to consciousness. As with attention-to-action and a sense of “me” buried in our thoughts and intentions, gamma seems to be a primary mindmaker. As two leading brain scientists, Rodolfo Llinás and Denis Paré, suggest, “Those aspects of brain function which form part of our consciousness must occur at the same time, most probably with 40-Hz activity” (Llinás, Paré, 1991: 531). Francis Crick, the co-discoverer of DNA, similarly asserts that such activity’s transiently binding fleeting attention to short-term memory makes for “vivid awareness” (Crick, Koch 1990; Koch , Crick 1994).
Inner Freedom
While it binds our attention, our memory, or even our preparation to do things, gamma itself might be just a correlate – a shadow, not the substance – of consciousness. Other brain activity may be inseparable from consciousness itself. At issue is what it is that gamma binds to create a “me.”
Our brains are constantly animating an embodied private life. When we are blindfolded, earplugged, and at rest, our prefrontal cortex still uses more energy than other parts of our brain, indicating that the mind is highly active (Roland 1984; 1993: 472). What is it doing?
It may be busy embodying a “me” feeling created around an inner world of questions about where we are and what is happening, or going to happen. Our brain is born to be constantly alive with such insistent queries. The world is perpetually changing around us. We must keep up with it: What does that comment mean? That tidbit of information? Or sound? To survive and learn, brains – we – must continually attend to the changes happening around us, which might be to our advantage or not.
Inner cues have a life of their own. Ideas play actively with each other, coming together in statements and questions. Consider the main inner cue used not only by your mind but in this book, indeed, in all books – words. Words empower us to describe and articulate, anticipate and question, better than we could with, say, images. They help us work out expectations and focus our concerns. Here, in the sketchpad of our thoughts, we hold court about what is happening within ourselves (Dehaene, Naccache 2001; Jack, Shallice 2001). If the prefrontal cortex enables the brain to organize its awareness by internal cues, many of them come from this inner conversation. We sense these cues as a voice – our inner one. Without speaking aloud, you hear yourself say “I.” Who is speaking?
It is you. According to the American philosopher of the mind Daniel Dennett, our inner voice is linked with consciousness. He suggests that this is a place (which is not really a place) where the brain tells itself stories about existing. To use one of his phrases, we have a “narrative center” (Dennett 1992). It is a sort of bulletin board or workspace that emerges from neural networks as the brain tries to keep track of its plans and concerns. According to Dennett, our continuity as a mind comes about as these self-told narratives unfold. We tell them to ourselves in inner speech. They organize and structure our actions and ambitions, the stories about ourselves that we tell others. They – we – are the inner prose our brains use to tell themselves and others what kind of person they are and want to be.
Here embodiment, subjectivity, and inner voice come together. As much as with our physical extension, we do things in our inner world so that we embody our inner voice with a sense of “me.” Gamma, binding the various threads of our inner voice with what is happening in the rest of our brain, may well be involved. Here, in doing this, the brain does, feels, and knows it exists. It acquires a first-person experience.
Part of the experience of consciousness is not only that this “me-ness” exists but that t acts as a free agent. Perhaps this reflects the brain’s concern with control. A brain that is awake to its opportunities and restrictions, after all, must always be attending to questions about the causal environment in antecedents and effects. We must spot how things happen. What follows my actions, and what determines them? Am I a causer, or am I caused? How can I gain control and escape restrictions? We seek the boundaries of our choice and our limitations. We attend to the scope of our intent and volition, and not just our own but those of other people as well. Social psychologists and those studying apes and monkeys find social position is determined by who can do what to whom. Low ranks are controlled by higher ones, never the other way around. We need to see causation for our welfare and survival.
Discovering how to make others respond to us (which often comes down to learning how to respond appropriately to them) also enables us to socialize. Think of 8-week-old babies. Although they can hardly manipulate the world, they can smile, laugh, and move their heads from side to side. Malcolm Watson, a psychologist, placed a mobile above the cots of 8-week-old babies and observed their movements (Watson, Ramsey 1972). Watson found that they laughed and smiled at the mobile, even before they had laughed and smiled at their own mothers. As infants grow up, they constantly seek ways of mastering their environment and engaging with things. We learn to play games like peek-a-boo. Finding islands of predictability gives us a sense of control even as it keeps us on the lookout for further surprises.
Some things clearly shape our actions. Take, for example, the laws of physics, the knife to our throat, the dictates of tyrants, poverty, and social obligations. But many things are within our control, if we wish to make them happen. We can move our hands, focus on the whiteness of this paper, plan a meal, cook it, and invite guests with whom to eat it. A previous generation might have sought such control in magic. We value it in the modern conveniences by which we have mastered our environment, such as the remote control, the private car, and the mobile phone.
Our thoughts are constantly focused on those things that might block our freedom and on how we might overcome them. We seek liberty of action, space in which to do whatever we want. To the degree we find it, we fee free; to the degree we do not, we feel trapped. Freedom affects our emotions; a stressful noise that we can turn off is not as stressful as one over which we lack control (Glass, Singer, Friedman 1969). A child feels fear of a toy when it cannot control it, but pleasure in it when it can (Gunnar-Vongnechton 1972). Children, not surprisingly, have a strong urge to gain a sense of mastery of things (Yarrow, McQuiston, MacTurk et al., 1983). They feel frustration when things that were controllable stop being so (Lewis, Sullivan, Ramsay Alessandri 1992). As adults we get frustrated over the aggravations and hassles of life. We bear them if we chose them; if not, we resent them or we try to gain control over them. In this way, our brains are steadily sensing out and, if possible, enlarging our “elbow room” (Dennett 1984). The prefrontal cortex is making its inner cues, after all, for a purpose – to give itself freedom from being limited by other people and what goes on around us. Here the brain searches out how to make things go along with its plans and desires. Thus, we wish the world to be contingent on us, not us on it (Brehm, Brehm 1981) We seek to do our own thing, not be the means to the ends of others. We desire to be the supreme causer in our affairs, not a puppet of events, pulled and pushed by necessity.
We can experience control through our prefrontal cortex’s internal cues. The outer world may frustrate us, but here inside, hidden from it, we are embodied in a “me” that feels at total liberty. We – our brains – therefore feel ourselves as agents in the world, even if it is only privately.
You can, for instance, think any thoughts you wish. You are entirely free in your mind. The only limits on your inner voice are your sense of logic and your imagination. You may lack the wings of the birds, but if you close your eyes you can be up in the air with them. Maybe your imagination is not always free – if you stub your toe, pain pulls your attention constantly to it, however much you seek to focus your mind elsewhere. That is a reason we dislike pain: It rules our attention! But when pain-free, we can focus with great liberty on such things as planning a date or writing a book. And we can do something else: Our minds can engage the senses to focus on the inputs into the brain’s experience. For instance, we can stop and attend to the whiteness of this paper or the blueness of the sky outside. Philosophers call this qualia – the whatness of experience. Your prefrontal cortex does this by manipulating and tuning its links to shift the attentive processes by which your visual cortex experiences what is before your eyes.
As we live through our inner cues and brain modulations, we can feel free and independent of the physical world outside the brain. But this interest in freedom is not only about physical limits. This brain experience we call “me” is as active in questioning its own constraints on its knowledge as in testing those it encounters in the physical world. It seeks to find freedom in the models and stories it tells itself. We tell stories that emphasize how we overcame restraints and how we determined what we did. We love tales of David against Goliath, Papillon escaping Devil’s Island, heroes who fight against the odds and succeed. In our lives, we play down how things shaped us. We may have been slaves to fortune, money, and others’ dictates, but we would rather tell ourselves stories in which we were not.
Is this true only of the stories of our everyday lives? Is it not also true of those with which we orient ourselves in the wider world of human knowledge? Within its embodied inner reality, the brain wants to tell itself stories tat it lives in a “metaphysical” world, one beyond nature. Here lies the threat we feel from those 100 billion cells in our skull. We fear that our inner volitions, in some distant way, are merely those of their matter, making us contingent to the physical world and its laws. No, we shake our heads, no, we – our brains – are separate, and somehow different, from mater, and so free. Material explanations of mind are experienced as traps; they threaten our prefrontal cortex’s embodied sense of having inner freedom. Our brain would rather not know that beyond its immediate senses it is merely another physical thing in the universe, that the restraints that limit and rule the outside world also, in a hidden way, limit and rule it. Our brain would rather tell itself stories that something exempt from outside influence makes it a free “me” or “I.”
This need to be free of the physical makes our brains sensitive and threatened by life’s end. We see loved ones decay in their brains, go demented and stop being the people we knew. We see them die, and know that the same fate awaits us. Here lies the horror that each brain faces in decay and death. Our freedom may have an end. It is a story our brain would prefer not to hear.
Beyond the Prefrontal Cortex
The prefrontal cortex cannot be the whole story of consciousness. People can injure their prefrontal cortex and still exist. They may lack empathy or an ability to plan or focus. They may not be inner driven and instead be tied to the world around them. But that does not necessarily mean they are not conscious. It might mean that they have a different experience; they may be less conscious but still have a kind of consciousness.
Also, as noted in Chapter 5, meditation puts the prefrontal cortex on standby without stopping consciousness. The calm awareness of meditation slows and halts its incessant activity. Yet here, with the prefrontal cortex turned down or off, consciousness still exists. Obviously, it is a different kind of consciousness. Indeed, it may be better in some ways richer in its attunement to the external experience to which normal consciousness gives short shrift.
Allegedly, practiced meditators can go beyond such calmness and experience transcendence. You might think that a book like this should not talk about such things, but some research requires that we should. The experience, according to meditators, goes beyond words. So it can only be hinted at. Gurus wave their hands, suggesting it is something like the knower, the known, and the process of knowing becoming one. They claim that ordinary experience is distorted and that only in meditation do people become truly aware of things. The problem, according to them, is that our lives are full of petty cares. While they are the necessary stuff of living, they also blind us to what exists beyond them.
Curiously, something happens to the brainwaves of meditators during “transcendence.” The prefrontal cortex does not stay turned off. When meditators who are wired to record their brain activity have signaled their entry into “transcendence,” gamma activity returns over their prefrontal cortices. In some meditators the activity appears not just in the prefrontal cortex, but all over their brains (Banquet 1973: 146; Sheer 1976: 77). Nobody knows what to make of this, but it suggests that a still unknown link connects the prefrontal cortex, gamma, and what Buddhists call nirvana.
The Brain’s Enigma
Is anything mentioned here or earlier in this book really you? In some ways all these phenomena seem to be. But it could be that they all touch just a little upon what it is to be, so that while none of them individually makes our minds, each makes its own, subtle contribution to consciousness, all dove-tailing into a unified experience of being alive. As the fragmented visual cortex appears unified in our vision, so it may be that the various activities of the mindmakers come together in the “I” of our mind.
Our minds must be distributed around our brains. It would seem rather odd if scientists were to announce they had found a square centimeter of our brains – the “me cortex,” say – that was solely responsible for consciousness. The individual processes involved are very diverse. We have been wholly ignorant of many of them until recently, and many more are yet to be discovered. But simply knowing that they exist demands that wee reverse philosophy’s understanding of how the brain relates to consciousness. Many philosophers hold, for instance, that the key fact of our experience is its apparent unity. Using this as a starting point, they investigate the nature of our being. But this could be a trap, misleading us into thinking that we are seeking one mysterious link between mind and brain. There may be no one such link. If anything, the problem is turning out to be one of too many mindmakers.
In the past, philosophers were just not in a position to have any deep insight into who we are. That may sound arrogant, but think of our bodies and the speculations of ancient doctors about blood, cholera, phlegm, and black bile – the four humors – before modern physiology and anatomy. Ancient doctors were hopelessly wrong. Until recently, philosophers were paddling upstream in the same boat with regard to brains. Medieval philosophers thought mind was in the brain’s ventricles. Descartes saw free will in the pineal gland. Taking an opposite approach, behaviorists denied consciousness existed; some twentieth-century philosophers even attributed it to an artifact of language usage. Without scanners to picture brains as they think and feel, how could anyone have started a serious investigation of what underlies our sense of who we are? The crucial information as to what went on in the brain was simply not there. But now lights are beginning to shine. As little information as we have, it dwarfs the cumulative knowledge of previous centuries. Embarking on a quest to the gray continent of the brain without this knowledge is as foolhardy as trying to make sense out of MRI scans of the body using Galen’s theory of the four humors.
To understand consciousness, we need to freshen our imaginations and free ourselves from the old stories about who and what we are. After all, it would not be the first time. To take one example, when we think that starts are made of matter like our Sun, we do something people 3000 years ago could not have grasped. For them, they were gods and spirits. It took the Greek Anaxagoras (500-428 BC) to break with this and suggest that the Sun might be a burning stone and that the moon might have a landscape of hills and ravines (Barnes 1987: 237). Old views of what is material and what is not have changed,, and we must be prepared for them to change again.
It is only now, after the turn of the third millennium, that humans can fully grasp what a wonderful thing the biocomputer in our skulls is. We are, in many ways, the first people in a position – thanks to neuroscience – to probe the key question of what it is to exist. But we need to be prepared to change some of the ways in which we expect that question to be answered.
So much to consider if we want to become not just adequate physical/physiotherapists, but superlative ones, who can help people be embodied, better.
No comments:
Post a Comment