Tales from Both Sides of the Brain
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Tales from Both Sides of the Brain

Michael S. Gazzaniga

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Tales from Both Sides of the Brain

Michael S. Gazzaniga

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About This Book

Michael S. Gazzaniga, one of the most important neuroscientists of the twentieth century, gives us an exciting behind-the-scenes look at his seminal work on that unlikely couple, the right and left brain. Foreword by Steven Pinker.

In the mid-twentieth century, Michael S. Gazzaniga, "the father of cognitive neuroscience, " was part of a team of pioneering neuroscientists who developed the now foundational split-brain brain theory: the notion that the right and left hemispheres of the brain can act independently from one another and have different strengths.

In Tales from Both Sides of the Brain, Gazzaniga tells the impassioned story of his life in science and his decades-long journey to understand how the separate spheres of our brains communicate and miscommunicate with their separate agendas. By turns humorous and moving, Tales from Both Sides of the Brain interweaves Gazzaniga's scientific achievements with his reflections on the challenges and thrills of working as a scientist. In his engaging and accessible style, he paints a vivid portrait not only of his discovery of split-brain theory, but also of his comrades in arms—the many patients, friends, and family who have accompanied him on this wild ride of intellectual discovery.

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Information

Publisher
Ecco
Year
2015
ISBN
9780062228819

PART 1

DISCOVERING THE BRAIN

CHAPTER 1

DIVING INTO SCIENCE

Physics is like sex: sure, it may give some practical results, but that’s not why we do it.
—RICHARD P. FEYNMAN
IN 1960, MOST COLLEGES WERE NOT CO-ED. I was at Dartmouth College, way out in the boonies of Hanover, New Hampshire, with hundreds of men. By the time summer came along, I had one thing on my mind. I applied for an internship at the California Institute of Technology because I wanted to spend the summer near a Wellesley girl I had met that winter. A glorious summer at Caltech, a fabled place for biology and discovery, ensued. She went on to other things. I got hooked on science. I often wonder, was I really there because of an insatiable interest in science? Or was it my interest in a girl who lived nearby? Who knows how it really works in the mercurial mind of the young? Ideas do occasionally worm their way into the interstitial areas of the hormone-addled mind.
For me, one of those thoughts was “But how does the brain make it all work?” I had also been drawn to Caltech by reading an article in Scientific American on the growth of nerve circuits, written by Roger Sperry.1 The article outlined studies on how a neuron grew from point A to point B in order to make a specific connection. A lot, indeed I would say most of neurobiology, hangs on that simple question. Sperry was the king and I wanted to learn more about that. Besides, as I said, my girlfriend lived down the street, in San Marino.
It wasn’t until years later when I was told about a remark made by Luis Alvarez, the great physicist from the University of California, Berkeley, that I realized that the impulse behind my question was not the same as simple curiosity. Alvarez remarked that scientists do their thing not because they are curious but because they instinctively feel something doesn’t work the way they are told it does.2 Their experimental minds kick into gear and think of another way that whatever is being discussed might work. While they can marvel at a finding or an invention, they instinctively, automatically, start thinking of alternative methods or explanations.
In my own case, I am always thinking about different ways of viewing a problem. In part, this is because of my impoverished quantitative skills. I don’t find math easy and usually shy away from highly technical discussions of almost everything. I have discovered that, in many cases, it is easy to look at a seemingly complex problem using everyday language. This is true because of the way the world is. After all, one doesn’t need to understand the atomic composition and quantum mechanics of the billiard ball’s atoms to play a game of pool. Simple, reliable classical physics is good enough.
We humans are all constantly abstracting, that is, taking a concrete reality and from it developing a larger theory and understanding. Thus we are continually coming up with a new, simpler layer of description that is easier for a limited brain capacity to manage. For example, take my truck. “Truck” is a new layer of description for the vehicle with open space to haul stuff and which is made up of a six-cylinder engine, radiator and cooling systems, chassis, and so forth. Now that I have a new description, every time I think about or refer to my truck, I don’t have to refer to all the parts and assemble them in my mind. I don’t have to think of them at all (until something goes wrong with one of them). We can’t deal with all the underlying complexities present in understanding the mechanisms of things every time we refer to them. It’s too much for our mental processes to handle. So we chunk it—give the mechanism a name, “truck,” thereby reducing its load on us from thousands or millions of items to one. Once we have an abstracted view of a previously highly detailed topic, then new ways of thinking about the topic—about how something works—become exhilaratingly clear. With the new key word and referent in hand, it is as if our minds are freed up to think again with new energy. Layers seems to be everywhere in Mother Nature.
What I will call the “layered” view of the world, which I will get back to later in the book, is an idea that comes out of the science of trying to understand complex systems such as cells, computer networks, bacteria, and brains. The concept of layering can be applied to almost any complex system, even our social world, which is to say our personal lives. One layer functions nicely, driving us with its particular reward systems. Then, suddenly, we can be bumped into another layer where different rules might apply. Caltech was going to be a new layer for me. Everything I saw and did was a “first,” and there were many.
At any rate, there I was, the summer between my junior and senior years at Dartmouth, nervously walking into Caltech for my first in this long series of firsts: meeting Roger Sperry in his Kerckhoff Hall office. He turned out to be a soft-spoken, sober guy who wasn’t rattled by much. I later heard that a few weeks before I met him, a monkey had gotten loose from the animal room and hopped into his office and up onto his desk. He looked up and said to his guest, “Maybe we should go next door. It might be quieter over there.”
Caltech has its own heady ambience. Everyone was really smart.3 Behind office doors were superior scientists of every type plying their trades. All universities claim that sort of thing (especially today, on their hyped-up Web pages), always extolling how truly “interdisciplinary” they are. The reality is usually quite different. But at Caltech, it was (and still is) the real deal: The engines are constantly running and then running into each other. The ethos of the place is captured by the old line, “I know he invented fire, but what has he done lately?” Working in a group that pushes you to think in unfamiliar ways is a rush. It is also challenging to keep up with the pace, to say the least. This was true for all of Caltech, and it was especially true of Roger Sperry’s lab (Figure 1).
image
FIGURE 1. The Sperry labs were on the third floor of Caltech’s Alles Laboratory, close to Linus Pauling’s office in the Church Chemistry Building. Across the way, in Kerchoff Hall, was A. H. Sturdevant, the father of drosophila genetics, and Ed Lewis, his Nobel Prize–winning student.
(Courtesy of the Archives, California Institute of Technology)
As a newcomer, I couldn’t get enough of it. In retrospect, probably no one knows which parts of one’s storyline account for the course one takes or explain how things turn out in one’s life. Surely there are both incidental and substantive things that result in us finding ourselves in new situations and circumstances. Just as mystifyingly, in those new places, we almost instantly become part of another dynamic and another knowledge base. Quickly enough, we strive to achieve new goals.
It soon became evident that another interest suffusing the lab, along with nerve growth circuits—the idea that hooked me into being there—was split-brain research, which was trying to find out if each hemisphere of the brain could learn independently from the other. The place was abuzz with postdocs examining monkey and cat behavior following split-brain surgery—surgery that disconnected the two half brains from each other. Where could I jump in?
I soon came up with the idea of making a “temporary split brain.” My idea was to study rats and to use a procedure dubbed “spreading depression.” In this procedure, a small piece of gauze or gelfoam would be soaked in potassium and placed over one hemisphere of the brain to induce sleep or inactivity, leaving the other awake and able to learn.4 One of the world’s authorities on the phenomenon of spreading depression, Anthonie van Harreveld, had an office next to Sperry, so consults were going to be easy. He was a kind and gentle soul and very approachable, especially when it came to science. Unfortunately, that experiment never went anywhere in my hands, probably because the rats gave me the creeps!
So, I turned to rabbits. Again, the idea was easy enough. Why not inject an anesthetic into the left or right internal carotid artery, which separately supplied the blood to the left or right hemisphere respectively. That would allow me to induce sleep in one hemisphere of the brain at a time, and leave the other half brain awake and able to learn. Would it work that way? At that time in science, and especially at Caltech, the only thing standing in the way of an idea or test was one’s energy and ability. No IRB (Institutional Review Board), no lack of funds, no discouraging cant from others, no endless regulations. You could just do it.
I had to have a measure of neural activity to make sure the appropriate half brain was asleep while the other was awake, so I began by pulling together an electroencephalograph, that is, an EEG. Then I had to learn how to teach a rabbit a trick so that it would learn something. We decided to teach the rabbit to blink an eyelid to a sound. I got that under control. Then I had to learn how to attach recording electrodes on the small rabbit skull in order to pick up the electrical activity, the EEG. I somehow managed to do that. Finally, I had to be able to inject into either the left or right internal carotid artery (the key arteries leading from the heart to the brain) an anesthetic and be convinced the drug stayed lateralized to half of the brain and didn’t leak over to the other half brain and thereby put it to sleep as well. After a lengthy library search on the anatomy of the Circle of Willis, the arterial structure at the base of the brain, I decided it would work in the rabbit. Even though it seemed that blood from both sides of the supplying arteries would mix at the Circle, some studies showed that, due to a special hemodynamics, it didn’t. I went ahead, convinced that hemodynamics would save the day and hoped an anesthetic applied to one carotid would stay long enough in one half brain for me to do the experiment. At last, I was ready to rock and roll.
My laboratory space for all of this was in the hallway in Sperry’s lab area. Space was tight, as there were many active postdocs toiling away with their own studies. One day I was busy doing a trial run. All the components were in place: the rabbit, the EEG machine recording the neural activity and spitting out the results on paper, and the eight ink pins fluttering back and forth. Then Linus Pauling walks by. Now, everybody knew who Linus Pauling was, particularly in our building, as his office was just around the corner in the chemistry building. He was one of the founders of quantum chemistry and molecular biology and was ranked as one the most important scientists of the twentieth century, making his way in 2000 onto an American stamp. Pauling stops and asks me what I’m doing. After sizing up the situation he says, “You know those squiggles you are ‘recording’ may be nothing other than the simple mechanical consequences of a Jell-O-like substance in a bowl. You ought to test that first.”5
As he walked on down the hall, I caught the fever. His message was simple: Assume nothing, young man, and test everything. No matter where you turned, people were challenging, questioning, poking, yet encouraging, and yes, supporting the notion that it might work differently, which urges the young scientist on. It was intoxicating. Little did I know that a couple of years later, after winning his second Nobel Prize, Pauling would be suing for libel William F. Buckley Jr., who was about to become my lifelong friend!
It was in this setting that a little over a year later, I tested the first split-brain patients. I wanted to see what people were like who for medical reasons had had the two hemispheres of their brain were surgically separated: the left brain no longer connected to the right brain. This book is about what that particular medical reality is, means, and taught us. The biographical details about the many scientists both directly and indirectly involved, who are featured in this telling, have been pruned from previous, mostly purely scientific accounts. As I have reflected on my own body of research, I feel it is important to grasp at least one tale of how many seemingly unrelated experiences flow together to make a life, and in this case, my life in science. But I am getting ahead of myself.
Over that all too short summer, I got the rabbit preparation to work. There was constant kibitzing from others in the lab, but the task I chose was mine to do. The notion of discovering a little bit of the way something worked was palpably exciting. I was seduced. I knew then I had to discuss this with my father. His dream was for me to follow in his and my brother’s footsteps and attend medical school. My father was a force. Breaking away from the padrone’s plan required a conversation.

ORIGINS

Dante Achilles Gazzaniga (Figure 2) was born in Marlboro, Massachusetts, in 1905. After attending St. Anselm’s College in Manchester, New Hampshire, he was bound for home to work at the boot factory where his father had worked since emigrating from Italy. The local priest intervened, the same one who had been instrumental in getting him to college. He told my father that if he studied chemistry and physics over the summer, he would arrange for him to go to medical school at Loyola, in faraway Chicago. Oh life was so simple and straightforward in those days. Learn the stuff and you get to go to the next step. And that is what he did. He went to Chicago in 1928, and with the money his mother had saved, he planned to buy himself a microscope. Unfortunately, the money was in the bank, and it was all lost in the 1929 crash.
image
FIGURE 2. Dante Achilles Gazzaniga dropped everything he was doing in Los Angeles to join the U.S. Navy and serve during World War II. He offered soldiers surgical care at bases in the New Hebrides and New Caledonia.
(Courtesy of the author)
In Chicago, he lived around the corner from where the infamous Valentine’s Day Massacre occurred, carried out by the gangster Al Capone. He even heard the shots on Clark Street. My father would sometimes get clam chowder at a local dive right by the alleyway where the shooting took place and sneak out packages of oyster crackers, which were a main part of his diet. To support himself and pay tuition, he played semipro football, as he was tall and strong, and he also ran an elevator, in which he did much of his homework. Somehow he got it done and I have thought about how different our experiences were, as I had enjoyed a paid research assistantship in luxurious Pasadena, California.
After four years of Chicago, he headed off to the train station with a plan: get on the first train heading to a sunny place. Successful in this goal, he stepped off in Los Angeles, where he did an internship at the famous County Hospital in 1932–33. Headed to the Rose Bowl game with his buddies, he was trotting down the hospital’s front steps on New Year’s Day 1933 when he first met my mother, who was on her way in to work. Three and a half months later, they were married. At one point in my mother’s lively life, she was the secretary to the famed Aimee Semple McPherson, the evangelist who founded the Foursquare Church and captured the imagination of Los Angeles with her sermonizing at the Angelus Temple she’d built. It may well have been that my mother’s famous father, Dr. Robert B. Griffith, had landed her the job in the media-conscious town. He was the first plastic surgeon in Los Angeles and a hugely talented and successful physician. Among his patients were Hollywood stars including Mary Pickford, Charlie Chaplin, cowboy star Tom Mix, and Marion Davies.
My mother’s father, whom I never met, was also known in local circles as a great chess player (masters level) and was a very good friend of Herman Steiner, the longtime chess columnist for the Los Angeles Times. They were both on their way back to Hollywood from a chess match in 1937 when they were hit head-on by a drunk driver. My mother found out that her father died in a car crash by reading the newspaper. I recently saw a pictur...

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