Part 9 (2/2)

CONCLUSION.

I was recently asked by a Time magazine reporter, ”If we could build a robot or an android that duplicated the processes behind human consciousness, would it actually be conscious?” It is a provocative question and it is one that persists, especially as one tries to capture the differences between the spheres of consciousness of animals and also those that exist between separated left and right brains. Much of what I have written here about bisected brains has appeared before. Yet, I find that the way we all nuance our understanding of complex topics is ever changing, since none of us hold the true answers in our hip pocket. I found myself answering the reporter with what I feel is a new twist.

Underlying this question is the a.s.sumption that consciousness reflects some kind of process that brings all of our zillions of thoughts into a special energy and reality called personal or phenomenal consciousness. That is not how it works. Consciousness is an emergent property and not a process in and of itself. When one tastes salt, for example, the consciousness of taste is an emergent property of the sensory system, not of the combination of elements that make up table salt. Our cognitive capacities, memories, dreams, and so on reflect distributed processes throughout the brain, and each of those ent.i.ties produces its own emergent states of consciousness.

In closing, remember this one fact. A split-brain patient, a human who has had the two halves of his brain disconnected from each other, does not find one side of the brain missing the other. The left brain has lost all consciousness about the mental processes managed by the right brain, and vice versa. It is just as with aging or with focal neurologic disease. We don't miss what we no longer have access to. The emergent conscious state arises out of each capacity and probably through neural circuits local to the capacity in question. If they are disconnected or damaged, there is no underlying circuitry from which the emergent property arises.

The thousands or millions of conscious moments that we each have reflect one of our networks being ”up for duty.” These networks are all over the place, not in one specific location. When one finishes, the next one pops up. The pipe organlike device plays its tune all day long. What makes emergent human consciousness so vibrant is that our pipe organ has lots of tunes to play, whereas the rat's has few. And the more we know, the richer the concert.

Part 4.

BEYOND CURRENT CONSTRAINTS.

Chapter 9.

WHO NEEDS FLESH?.

The principles now being discovered at work in the brain may provide, in the future, machines even more powerful than those we can at present foresee.

-J. Z. Young, Doubt and Certainty in Science: A Biologist's Reflections on the Brain, 1960.

Men ought to know that from the brain, and from the brain only, arise our pleasures, joy, laughter and jests, as well as our sorrows, pains, griefs, and tears.

-Hippocrates, c. 400 B.C.

I AM A FYBORG, AND SO ARE YOU. FYBORGS, OR FUNCTIONAL cyborgs, are biological organisms functionally supplemented with technological extensions.1 For instance, shoes. Wearing shoes has not been a problem for most people. In fact, it has solved many problems, such as walking on gravelly surfaces, avoiding thorns in the foot, walking at high noon across an asphalt parking lot on a June day in Phoenix, or a January day in Duluth, and shoes have prevented over one million stubbed toes in the last month. In general, no one is going to get upset about the existence and use of shoes. Man's ingenuity came up with a tool to make life easier and more pleasant. After the inventors and engineers were done with the concept, the basic design, and product development, the aesthetics department took over, cranked it around a bit, and came up with high heels. Perhaps not so utilitarian, but they serve a different, more specific purpose: to get across that parking lot looking s.e.xy.

Wearing clothes has also been well accepted. They provide protection both from the cold and the sun, from thorns and brush, and can cover up years' worth of unsightly intake errors. Watches, a handy tool, are used by quite a few people without any complaint, and are now usually run by a small computer worn on the wrist. Eyegla.s.ses and contact lenses are common. There was no big revolution when those were introduced. Cell phones seem to be surgically attached to the palms of teenagers and, for that matter, most everyone else. Fas.h.i.+oning tools that make life easier is what humans have always done. For thousands of years, we humans have been fyborgs, a term coined by Alexander Chislenko, who was an artificial-intelligence theorist, researcher, and software designer for various private companies and MIT. The first caveman that slapped a piece of animal hide across the bottom of his foot and refused to leave home without it became a fyborg to a limited degree. Chislenko devised a self-test for functional cyborgization: Are you dependent on technology to the extent that you could not survive without it?

Would you reject a lifestyle free of any technology even if you could endure it?

Would you feel embarra.s.sed and ”dehumanized” if somebody removed your artificial covers (clothing) and exposed your natural biological body in public?

Do you consider your bank deposits a more important personal resource storage system than your fat deposits?

Do you identify yourself and judge other people more by possessions, ability to manipulate tools and positions in the technological and social systems than primary biological features?

Do you spend more time thinking about-and discussing-your external ”possessions” and ”accessories” than your internal ”parts”?1 I don't know about you, but I would much rather hear about my friend's new Maserati than his liver. Call me a fyborg any day.

Cyborgs, on the other hand, have a physical integration of biological and technological structures. And we now have a few in our midst. Going beyond the manufacture of tools, humans have gotten into the business of aftermarket body parts. Want to upgrade that hip or knee? Hop up on this table. Lost an arm? Let's see what we can do to help you out. But things start getting a little bit dicier when we get to the world of implants. Replacement hips and knees are OK, but start a discussion about breast implants, and you may end up with a lively or heated debate about a silicon upgrade. Enhancement gets the ire up in some people. Why is that? What is wrong with a body upgrade?

We get into even choppier waters when we start talking about neural implants. Some people fear that tinkering with the brain by use of neural prostheses may threaten personal ident.i.ty. What is a neural prosthesis? It's a device implanted to restore a lost or altered neural function. It may be either on the input side (sensory input coming into the brain) or the output side (translating neuronal signals into actions). Currently the most successful neural implant has been used to restore auditory sensory perception: the cochlear implant.

Until recently, ”artifacts” or tools that man has created have been directed to the external world. More recently, therapeutic implants-such as artificial joints, cardiac pacemakers, drugs, and physical enhancements-have been used either below the neck or for facial cosmetic purposes (that would include hair transplants). Today, we are using therapeutic implants above the neck. We are using them in the brain. We also are using therapeutic medications that affect the brain to treat mental illness, anxiety, and mood disorders. Things are changing, and they are changing rapidly. Technological and scientific advances in many areas, including genetics, robotics, and computer technology, are predicted to set about a revolution of change such as humans have never experienced before, change that may well affect what it means to be human-changes that we hope will improve our lives, our societies, and the world.

Ray Kurzweil, a researcher in artificial intelligence, makes the point that knowledge in these areas is increasing at an exponential rate, not at a linear rate.2 This is what you would like your stock price to do. The cla.s.sic example of exponential growth is the story about the smart peasant of whom we learned in math cla.s.s-the guy who worked a deal with a math-challenged king for a grain of rice on the first square of a chessboard, and to have it doubled on the second, and so on, until by the time the king had reached the end of the chessboard, he had lost his kingdom and then some. Across the first row or two of the chessboard things progressed rather slowly, but there came a point where the doubling was a hefty change.

In 1965, Gordon Moore, one of the cofounders of Intel, the world's largest semiconductor manufacturing company, made the observation that the number of transistors on an integrated circuit for minimum component cost doubles every twenty-four months. That means that every twenty-four months they could double the number of transistors on a circuit without increasing the cost. That is exponential growth. Carver Mead, a professor at Caltech, dubbed this observation Moore's law, and it has been viewed both as a prediction and a goal for growth in the technology industry. It continues to be fulfilled. In the last sixty years, computation speed, measured in what are known as floating point operations per second (FLOPS), has increased from 1 FLOPS to over 250 trillion FLOPS! As Henry Markram, project director of IBM's Blue Brain project (which we will talk about later), states, this is ”by far the largest man-made growth rate of any kind in the ~10,000 years of human civilization.”3 The graph of exponential change, instead of gradually increasing continually as a linear graph would, gradually increases until a critical point is reached and then there is an upturn such that the line becomes almost vertical. This ”knee” in the graph is where Kurzweil thinks we currently are in the rate of change that will occur owing to the knowledge gained in these areas. He thinks we are not aware of it or prepared for it because we have been in the more slowly progressing earlier stage of the graph and have been lulled into thinking that the rate of change is linear.

What are the big changes that we aren't prepared for? What do they have to do with the unique qualities of being human? You aren't going to believe them if we don't work up to them slowly, so that is what we are going to do.

SILICON-BASED AIDS: THE COCHLEAR IMPLANT STORY.

Cochlear implants have helped hundreds of thousands of people with severe hearing problems (due to the loss of hair cells in the inner ear, which are responsible for transmitting but also augmenting or decreasing auditory stimuli) for whom a typical hearing aid does not help. In fact, a child who has been born deaf and has the implants placed at an early enough age (eighteen to twenty-four months being optimal) will be able to learn to speak normally, and although his hearing may not be perfect, it will be quite functional. Wonderful as this may sound, in the 1990s, many people in the deaf community worried that cochlear implants might adversely affect deaf culture and that, rather than a therapeutic intervention, the devices were a weapon being wielded by the medical community to commit cultural genocide against the deaf community. Some considered hearing an enhancement, an additional capability on top of what other members of the community had, gained by artificial means. Although people with cochlear implants can still use sign language, apparently they are not always welcome.4 Could this reaction be a manifestation of Richard Wragham's theory, which we learned about in chapter 2, that humans are a party-gang species with in-group/out-group bias? This att.i.tude has slowly been changing but is still held by many.

To understand cochlear implants, and all neuroprosthetics, it is important to also understand that the body runs on electricity. David Bodanis, in his book Electric Universe, gives us a vivid description: ”Our entire body operates by electricity. Gnarled living electrical cables extend into the depths of our brains; intense electric and magnetic force fields stretch into our cells, flinging food or neurotransmitters across microscopic barrier membranes; even our DNA is controlled by potent electrical forces.”5 A DIGRESSION ON ELECTRIC CITY.

The physiology of the brain and central nervous system has been a challenge to understand. We haven't talked much about physiology, but it is the structure underneath all that occurs in the body and brain. All theories of the brain's mechanisms must have an understanding of the physiology as their foundation. The electrical nature of the body and brain is perhaps most easily digested bit by bit and, luckily for our digestion, the continuing unfolding story began in one of the most tasty cities of the world, Bologna, Italy. In 1791, Luigi Galvani, a physician and physicist, hung a frog's leg out on his iron balcony rail. He had hung it with a copper wire. The dang thing started twitching. Something was going on between those two metals. He zapped another frog's leg with a bit of electricity, and it twitched. After further investigation, he suggested that nerve and muscle could generate their own electrical current, and that was what caused them to twitch. Galvani thought the electricity came from the muscle, but his intellectual sparring partner, physicist Alessandro Volta, who hailed from the southern reaches of Lake Como, was more on the mark, thinking that electricity inside and outside the body was much the same type of electrochemical reaction occurring between metals.

Nearly a hundred years go by, and another physician and physicist, from Germany, Hermann von Helmholtz, who was into everything from visual and auditory perception to chemical thermodynamics and the philosophy of science, figured out a bit more. That electrical current was no by-product of cellular activity; it was what was actually carrying messages along the axon of the nerve cell. He also figured out that even though the speed at which those electrical messages (signals) were conducted was far slower than in a copper wire, the nerve signals maintained their strength, but those in the copper did not. What was going on? Well, in wire, signals are propagated pa.s.sively, so that must not be what is going on with nerve cells. Von Helmholtz found that the signals were being propagated by a wavelike action that went as fast as ninety feet per second. Well, Helmholtz had done his bit and pa.s.sed the problem on.

How did those signals get propagated? Helmholtz's former a.s.sistant, Julius Bernstein, was all over this problem and came up with the membrane theory, published in 1902. Half of it has proven true; the other half, not quite.

When a nerve axon is at rest, there is a 70-millivolt voltage difference between the inside and the outside of the membrane surrounding it, with the inside having a greater negative charge. This voltage difference across the membrane is known as the resting membrane potential.

When you get a blood panel done, part of what is being checked are your electrolyte levels. Electrolytes are electrically charged atoms (ions) of sodium, pota.s.sium, and chlorine. Your cells are sitting in a bath of this stuff, but ions are also inside the cells, and it is the difference in their concentrations inside and outside of the cell that const.i.tutes the voltage difference.

Outside the cell are positively charged sodium ions (atoms that are short an electron) balanced by negatively charged chloride ions (chlorine atoms carrying an extra electron). Inside the cell, there is a lot of protein, which is negatively charged, balanced by positively charged pota.s.sium ions. However, since the inside of the cell has an overall negative charge, not all the protein is being balanced by pota.s.sium. What's up with that? Bernstein flung caution to the wind and suggested that there were selectively permeable pores (now called ion channels), which allowed only pota.s.sium to flow in and out. The pota.s.sium flows out of the cell and remains near the outside of the cell membrane, making it more positively charged, while the excess of negatively charged protein ions make the inside surface of the membrane negatively charged. This creates the voltage difference at rest.

But what happens when the neuron fires off a signal (which is called an action potential)? Bernstein proposed that for a fraction of a second the membrane loses its selective permeability, letting any ion cross it. Ions would then flow into and out of the cell, neutralizing the charge and bringing the resting potential to zero. No big fancy biochemical reactions were needed, just ion concentration gradients. This second part later needed to be tweaked a bit, but first we encounter another physician and scientist, Keith Lucas.

In 1905, Lucas demonstrated that nerve impulses worked on an all-or-none basis. There is a certain threshold of stimulation that is needed for a nerve to respond, and once that threshold is reached, the nerve cell gives its all. It either fires fully, or it does not fire: all or nothin,' baby. Increasing the stimulus does not increase the intensity of the nerve impulse. With one of his students, Baron Edgar Adrian, he discussed trying to record action potentials from nerves, but World War I intervened, and Lucas died in an airplane accident.

Adrian spent World War I treating soldiers for nerve damage and sh.e.l.l shock, and when it ended, he returned to his alma mater, Cambridge, to take over Lucas's lab and study nerve impulses. Adrian set out to record those propagated signals, the action potentials, and in doing so, found out a wealth of information and bagged a n.o.bel Prize along the way.

Adrian found that all action potentials produced by a nerve cell are the same. If the threshold has been reached for generating the signal, it fires with the same intensity, no matter what the location, strength, or duration of the stimulus is. So an action potential is an action potential is an action potential. You've seen one, you've seen them all. Now this was a bit puzzling. If the action potentials were always the same, how could different messages be sent? How were stimuli distinguished? How could you tell the difference between a flaccid and a firm handshake, between a sunny day and a moonlit night, between a dog bark and a dog bite?

Baron Adrian discovered that the frequency of the action potentials is determined by the intensity of the stimulus. If it is a mild stimulus, such as a feather touching your skin, you get only a couple of action potentials, but if it is a hard pinch, you can get hundreds. The duration of a stimulus determines how long the potentials are generated. If, however, the stimulus is constant, although the action potentials remain constant in strength, they gradually reduce in frequency, and the sensation is diminished. And the subject of the stimulus, whether it is perceptual (visual, olfactory, etc.) or motor, is determined by the type of nerve fiber that is stimulated, its pathway, and its final destination in the brain. Adrian also figured out something cool about the somatosensory cortex, the destination of all those perception neurons. Different mammals have different amounts of somatosensory cortex for different perceptions: Different species do not have equal sensory abilities; it all depends on how big an area in their somatosensory cortex is for a specific ability.

This also applies to the motor cortex. Pigs, for instance, have most of their somatosensory cortex dedicated to their snout. Ponies and sheep also have a big nostril area; it is as large as the area for the entire rest of their bodies. Mice have a huge whisker area, and racc.o.o.ns have 60 percent of their neocortex devoted to their fingers and palm. We primates have big hand and face areas, for both sensation and motor movement. You get more bang for your buck when you touch something with your index finger than when you use other parts of your body. This is why when you touch an object with your finger in the dark, you are more likely to be able to determine what it is than if you touch it with your back. It is also why you have such dexterous hands and such an expressive face. However, we will never know what it is like to have the perceptions of a pig. Although the basic physiology is the same, the hookups and the motor and somatosensory areas are different among mammalian species. Part of our unique abilities and experiences, and the uniqueness of every animal species, lies in the makeup of the motor and somatosensory cortex.

Next, Alan Hodgkin, one of Adrian's students, figured out that the current generated by the action potential was more than enough to excite an action potential in the next segment of an axon. Each action potential had more power than it needed to spark the next one. So they could perpetuate themselves forever. This was why, once generated, they didn't lose their strength. Later, Hodgkin and one of his students (are you following the genealogy?), Andrew Huxley, tweaked Bernstein's membrane theory, and also received a n.o.bel Prize for their work. Studying the gigantic squid neuron, the largest of all neurons (picture a strand of spaghettini), they were able to record action potentials from inside and outside the cell. They confirmed the70-millivolt difference that Bernstein had proposed, but found that in the action potential, there was actually a 110-millivolt change, and the inside of the cell ended up with a positive

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