Tales from Both Sides of the Brain : A Life in Neuroscience (9780062228819)

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Tales from Both Sides of the Brain : A Life in Neuroscience (9780062228819) Page 10

by Gazzaniga, Michael S.


  Somehow I survived the guilt of producing the pictures and ran the test, first on N.G (Video 6). I had the camera all set up. It would catch any facial expression she might have, but since it was back in the silent film days, there would be no voice recording. Luckily the film was clear, and one could see her reacting to my questions.

  MSG: Fixate the dot.

  N.G.: Okay.

  A picture of a spoon was flashed to the left visual field, which revealed its contents solely to the right hemisphere.

  MSG: What did you see?

  N.G.: Nothing.

  Expressionless reaction on her face.

  MSG: Okay, fixate the dot.

  This time a picture of a nude woman was presented to the right hemisphere.

  MSG: What did you see?

  N.G.: Nothing.

  . . . but she then fights off a grin and finally lets it all out and does a full chuckle.

  MSG: Why are you laughing?

  N.G.: Oh, I don’t know. That is a funny machine you have there.

  I was excited with this result, though it would be several years before I fully understood its implications. At the time, I simply wanted very much to confirm it with W.J. A few days later I piled all my testing gear into my Studebaker and drove off to Downey. I flashed several neutral pictures to W.J. before flashing the nude picture to the right hemisphere of this World War II veteran. Again I asked, “What did you see?” With the most expressionless face I think I have ever seen, he replied, “Nothing.” I was so disappointed. Maybe the test on N.G. was a fluke.

  To be complete, of course, I tested W.J.’s left, talking hemisphere directly. To my surprise, and without expression of any kind, W.J. said “A pinup?” I said, “Yes.” As I was fiddling around with my gear, W.J. dryly added, “Is that the kind of co-ed you have at Caltech?” So there you go. Neither hemisphere found the nude engaging. Linus Pauling was right: Never assume anything.

  LEAVING THE NEST

  I took the phone call from Howard Kendler, the chair of UCSB’s Psychology Department, on the hallway phone in the Alles Laboratory at Caltech. Phones were not allowed in individual offices in Sperry’s lab, and probably for good reason. When the phone rang, it was sort of an anti-signal: Answering it would invariably interrupt what you were doing. As it was, occasionally, you still had to pick it up and then go fetch somebody. Phones were a pain in the neck.

  Nonetheless, it was my turn to take a call. I picked up and Howard said, “We would like to hire you as an assistant professor here at UCSB at the startling salary of nine thousand, five hundred dollars for nine months.” A nine-month offer meant you had to find your own salary for the other three months through grants or other means. As in the moment before a car crash, some vital issues flashed through my mind as he spoke. First, like it or not, it was time to leave Caltech. I had been there five years, and new students were coming in to pick up the ball. Second, I had accepted a postdoctoral fellowship in Pisa to work with my dear friend Giovanni Berlucchi. Third, I needed a job when I came back. And fourth, I would be within a hundred miles of Caltech and close to the patients, so I could continue research. Then and there I heard myself saying, “I’ll take it!” And that was that.

  Of course, the decision was not without pain and a sense of loss. I had grown up into the ways of not only the scientific world but also the social world at Caltech, which included political meanderings. My friendship with Bill Buckley had deepened, and in 1964 he invited me to be his sidekick at the Republican National Convention in San Francisco. The great American author John Dos Passos, who had become conservative after his flaming left-wing youth, was there to write an article on the convention for National Review. Bill gave me the assignment of shepherding him. One-eyed, in his seventies, Dos Passos had more energy than six young men. I could barely keep up. It was a sublime experience, capped off by the last night’s chore of typing out his piece. It took me all night. The next afternoon, when I saw Bill, who had just been debating Gore Vidal, he calmly said to me, “Mike, I can see typing is not your strong card.” Oh well. It wasn’t.

  I was involved in other political functions at Caltech, including Martin Luther King Jr.’s final visit there in 1965. In the evening, he spoke at the historic Friendship Baptist Church in Old Town Pasadena. It was the first black Baptist church in the city. I was able to get into the back of the church for the sermon, which turned out to be one of the most moving experiences of my life. And there was more. Robert Kennedy came to Caltech in 1964 and writer James Baldwin came in 1963. Meeting such vibrant and driven public figures couldn’t help but mature one’s thinking about the social world. Baldwin, in particular, was moving. I had the honor of spending an evening in conversation with him in a smoke-filled den at the home of a Pasadena patron. He said that he had moved to Paris years before in order to feel more free as both an African American and a homosexual. When asked why he returned to the States, he simply declared that even though Paris had many advantages, he was an American at the core. (In the small-world department, a couple of years later, Baldwin and Buckley were in a much-reported debate at the Cambridge Union Debating Society in England. Baldwin was declared the winner.)

  Now it was time to move on from the lively world of Caltech into my own academic position. Before settling in to that life, it was off to Italy to train with Berlucchi. We had an idea, one so painfully simple and naïve that it cracks us up to even think about it today. The reasoning went like this: Callosum-intact persons can name objects and words in each visual field. Speech is only in the left brain. That means stimuli presented to the right hemisphere by flashing in the left visual field had to somehow transfer over the callosum to the left hemisphere in order to be expressed. By recording in the corpus callosum, we could figure out the brain code! It would be like the Morse code of the brain or something cool like that.

  Now, there are lots of reasons to go to Italy, science being only one of them. I have often thought the world should simply turn Italy into something like a national park for the world to enjoy. It is simply stunning, deep, loaded with history, art, and fun; delicious, crazy, breathtaking, irreverent, and hilarious. Forty-five years ago I was about to learn all of this from my first experience in Pisa.

  My wife, my two-year-old daughter, Marin, and I were driving down from Paris in a small VW bug and were going to arrive in Pisa very late, around 2 A.M. It was dark, windy, and raining as I sped down the highway. Things were looking pretty bleak and were about to get bleaker: I saw the flashing red lights of the carabinieri in my rearview mirror signaling me to pull over. My heart sank as the officer approached the car. I didn’t speak Italian; he didn’t speak English. After an exchange of stern pleasantries, he asked for my license and passaporto. None of these documents produced a change in the stern expression on his face. He then, as best I could figure out, asked me what we were doing in Italy. I think I figured this out because I heard the word turista in there somewhere. Luckily, I had a letter from Giuseppe Moruzzi, the famous Italian neurophysiologist who ran the Istituto di Fisiologia in Pisa. I fished it out and handed it to him. He took it with some disdain and focused his flashlight on it. As he read it, and before my very eyes, he was transformed into a highly respectful servant of the public. “Mi scusa, Professore . . .” I didn’t see any reason to correct him on my lowly academic status. Before I knew it, we were on our way with no problems and no citation. I probably could have had an escort if I’d known how to ask. The police respect professors? Wow! I knew then that I loved Italy, my genetic home.

  Once settled into a beautiful apartment that had been arranged for us to rent, it was off to work at the Istituto, a beautiful building only a few blocks from our apartment. No room was available in the main building to set up a lab, so Giovanni arranged for us to use a spare building situated in the garden. So there we were. We had some kind of idea and an empty room. It was time to go to work.

  Also at the Istituto was Giacomo Rizzolatti, a young neurophysiologist of enormous talent, who
later went on to discover mirror neurons (the group of neurons we all possess that track the actions of others). Giacomo and Giovanni (Figure 13) were to become very close friends. Both were superior neurophysiologists, and they were going to try to teach me the trade. It would be a whole new world, a different kind of biology, a time-consuming, demanding, and exacting skill. First, however, we needed to set up for the experiments. In general terms, we needed an operating platform, recording equipment, a projector, a screen, and cats. Berlucchi decided we needed a special screen, a half-dome kind of thing so as the cat gazed ahead, every point on the screen would be equidistant from its eyes. A metal welder in town made stuff, all kinds of stuff, but I can assure you he had never made a half dome out of bent steel for a cat to gaze upon. He seemed game, however, when Berlucchi explained the project, and, although a bit disbelieving, built a half dome. It was delivered on a trailer, drawn behind one of those little scooter trucks you see all over Italy. As it approached, everybody started to laugh. We had a problem. It was too big to get through the door into the lab.

  FIGURE 13. The Istituto Fisologia in Pisa gave Giacomo Rizzolatti (top) and Giovanni Berlucchi (bottom) and me space in the garden to carry out our experiments. Both Berlucchi and Rizzolatti became distinguished scientists, recognized throughout Italy and the world.

  (Courtesy of Giovanni Berlucchi)

  Unperturbed, Giovanni declared, “Non c’è problema.” He ordered the dome cut in half in such a way that it could be bolted back together once the pieces were inside the room. It got done. Meanwhile Pasquale, the lab animal technician, found cats for us. Oh, how things were different in those days. Cats did not come from some highly regulated biomedical animal provider, as they have now for at least thirty years. Cats came from the alley! It was Pasquale’s job to keep the labs provided with cats. These were no lap cats. These were feral street cats, wild and mean. Even once they were caught and placed into cages, it was a challenge to anesthetize them.

  As all of the elements were coming together, Roger Sperry came from Caltech to visit us. He was passing though Italy and stayed with us while in Pisa. As I say, we had the benefit of a wonderful apartment with a guest room, with the only caveat that the guest bathroom’s toilet ran a little too long after flushing. Roger, feeling right at home, got the necessary tools, climbed up to the ceiling, and fixed it. He was making sure we were settled in, and we all had a grand time.

  Finally, the big day arrived at the lab. Giovanni and Giacomo had perfected the essential operation, which some called the encéphale isolé preparation,6 no slight feat in itself. This allowed the animal to be tested painlessly while awake and staring at the half-dome screen, visualizing the stimuli we projected onto it. In addition, a single electrode could be lowered into the corpus callosum, and we could eavesdrop on the neural signals that were being passed over the callosum between the hemispheres.

  Amid great anticipation, Giacomo slowly lowered the electrode into the callosum. As is commonly done in neurophysiology, the recording system was hooked up to a loudspeaker so that the rat-tat-tat of the neurons firing could be heard. We were ready to hear the Morse code of the brain.

  Then it happened. The electrode pierced the callosum. Instead of the rat-tat-tat we expected, the loudspeaker boomed with the excruciatingly clear voice of Ringo Starr singing, “We all live in a yellow submarine, a yellow submarine, a yellow submarine.” Giacomo looked up from the cat and calmly said, “Now that is what I call high-order information.” Some kind of electronic ground loop had been closed, and we were picking up the local radio station. We all laughed, though we knew this brain code thing was going to be a long haul.

  In the end we did complete a nice piece of research.7 We showed how the individual neurons in the callosum coded for visual information, either to one side of the visual midline or the other. In follow-up studies over the next year, Berlucchi and Rizzolatti were able to show exactly how the callosum enables the actual two halves of our visual world to seem like only one. The Nobel laureate David Hubel describes the experiment and called it the best example of exquisite neural specificity that he knew:

  Having cut the optic chiasm along the midline, they made recordings from area 17, close to the 17–18 border on the right side, and looked for cells that could be driven binocularly. Obviously any binocular cell in the visual cortex on the right side must receive input from the right eye directly (via the geniculate) and from the left eye by way of the left hemisphere and corpus callosum. Each binocular receptive field spanned the vertical midline, with the part to the left responding to the right eye and the part to the right responding to the left eye. . . .

  This result showed clearly that one function of the corpus callosum is to connect cells so that their fields can span the midline. It therefore cements together the two halves of the visual world. . . .8

  ITCHIN’ FOR MY OWN LABORATORY

  After a few months in Pisa, I was discovering that neurophysiology was not for me. It takes long hours, as all research does, but also great patience, not my strong suit. I was ready to get back and start my own academic life. I missed testing patients, I had a bunch of follow-up experiments I wanted to do, and Santa Barbara seemed a long way from Pisa: I was beginning to feel isolated and out of the loop. I wrote Kendler, the UCSB psychology chairman, and asked him if I could return early and start in January instead of July. He somehow made it work at that end, and my friend Giovanni arranged to terminate my fellowship short by six months in Pisa. Overall, it wasn’t my finest hour, but that is what happened.

  The excitement of a new job, a new academic rank, a new sense of destiny all colored my early impressions of the University of California, Santa Barbara, in 1967. It is a spectacularly beautiful setting, and the psychology department was full of talented people, including David Premack. Most of the department came out of classic experimental psychology, a whole new world to me. I was so enthusiastic that I asked Sperry if he would consider a job at Santa Barbara. It turns out that this is a fairly common pattern. Sperry actually came up and visited, and I think he even met with the chancellor, but in the end, it didn’t work out.

  What did work out was my first grant, which I had applied for before taking off for Pisa. I had written it during my last year at Caltech and was able to have it checked by Sperry and others in the lab. It was about both animal and human work that I wanted to continue. Everyone said it was good and wished me good luck. In the 1960s, grants were fairly easy to get, and my good luck continued. Although I hadn’t realized it at the time, Sperry was chair of the NIH study section that reviewed the grant. I am sure he had to recuse himself for its evaluation, but it never hurts to have someone on the committee who is knowledgeable about the topic, even if they are standing outside the door. When I arrived at Santa Barbara, I was able to set up my monkey lab quickly and also to start testing patients again.

  Most psychologists don’t have the luxury of testing patients whose hemispheres are disconnected, a condition that makes the examination of the separated hemispheres relatively easy. Experimental psychologists measure how long things take to do, or how many errors people make when doing some kind of task. From those kinds of observations, they build a model about how such-and-such might work and that, indeed, there is a mental life guiding our behavior. They are really good at it, too. I was surrounded by that kind of expertise at Santa Barbara.

  One of the issues the early split-brain work had helped to frame was the question of how information gets integrated into the regularly intact normal brain. When we look out at the world and see a scene, each half of what we see goes to a different hemisphere. Yet, to each of us, it all seems to be one unified scene with no stitching up the middle, no gap in appreciating the left side of the scene versus the right side. How does that work? Maybe all is not gapless. Maybe detectable timing differences do exist and are somehow masked? We made an early contribution to this kind of question using a very simple test.

  Undergraduates at Santa Barbara were broug
ht in, and my new graduate student, Robert Filbey, began testing them. Filbey, with his John Lennon glasses and long curly hair, was a wonderful soul and free spirit. His roommate at Pomona College had been Larry Swanson, who went on to be one of the world’s leading and most imaginative neuroanatomists. In contrast, after this experiment, Filbey decided that graduate school was not for him and retreated to Garberville, California, to live life as an artist. Over the years, his drawings have graced my books, and his wit is endless. But back then, he was working hard in the lab.

  The task was for our volunteers to fixate on a point on a screen that was equipped with both a voice-operated relay and a simple manual electronic key. On the first set of tests, a dot flashed up on the screen after a warning buzzer, and it appeared either to the left or right of fixation. Half of the subjects were told to say “yes” if a dot appeared, and “no” if the screen remained blank, which is to say, if nothing appeared. The other half of the subjects were told the opposite: Say “yes” if the screen remained blank (nothing appeared) and “no” if a dot appeared. The results were intriguing.

  When the dot came on in the left visual field or when it was a blank trial, the verbal response, which had to come from the left hemisphere, was 30 milliseconds slower than when the dot was presented in the right visual field. Thus it appeared that when the dot was initially projected to the left, speaking hemisphere (from the right visual field), the overall response was much faster. But when there was a blank trial in the left visual field, the response was slower, because after all, the fact that nothing was presented had to be deduced by the left, speaking hemisphere, and9 the left hemisphere must have been waiting for the right hemisphere to report in, and that took time.

 

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