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

by Gazzaniga, Michael S.

  FIRST FILMS: THE BEGINNINGS OF THE LEFT BRAIN/RIGHT BRAIN DISTINCTION

  Ideas for things we should study kept rolling in. In the beginning we took them on, or at least initiated them, quickly and rather easily. While Sperry was unquestionably interested in the studies, they had not yet captured his full attention. As I already mentioned, he was extremely busy with his other exceptional projects. Like a financier, he had placed a bet on a small company, of which I was the chief operating officer, and he was waiting for enduring returns. He kept closely involved with almost daily meetings with me, but he had a way of keeping a distance as well. As Bogen wrote in his autobiography:

  Then a lot of things came after that. In the beginning Sperry was not that interested. He just thought he would let me and Gazzaniga do it. But it became apparent to Sperry after the second patient that anything you could do with a monkey you could do a lot faster with human beings. He got a lot more interested.20

  Back east, Norm Geschwind complained a bit about his original observations not receiving instant recognition beyond the local Boston buzz. He wrote: “As a reflection of this lack of interest it is interesting to observe that when Edith Kaplan and I described the first modern patient with the syndrome of the corpus callosum, the paper was rejected by the New England Journal of Medicine without any comment.”21

  The journal Neurology was interested, however, and accepted it. It is not unusual for big discoveries not to be recognized as such. Paul Lauterbur’s first attempt at publishing his work that led to the development of MRI (magnetic resonance image) was rejected by the journal Nature. He went on to win the 2003 Nobel Prize in Physiology or Medicine for it. He later quipped, “You could write the entire history of science in the last 50 years in terms of papers rejected by Science or Nature.”22

  I have come to realize that, for a short while, the enthusiasms of discovery can be quite local to the person doing the work. The world is a busy place and everyone is vested in what they are doing. Grabbing their attention away from their current passions is a process. David Premack, one of world’s most talented psychologists, once observed that after he published his paper in Science (groundbreaking studies that led up to his theory of motivation—what later became called the “Premack Principle”), he thought it would all be easy from there. He remarked to me, “Little did I know I would spend the next ten years hitting the road to sell it at every departmental colloquium I could find.”

  Sperry’s interest did indeed come around. I would be left with no doubt about that after a talk I was asked to give to the biology department, a sort of sounding-board seminar for graduate students. When I gave the talk, I had been working on the split-brain project for at least two years and was deeply into all aspects of the testing program. But it was the films I showed that were the showstoppers.

  From the beginning, I had been intent on establishing a film record of the experiments. In 1962, video cameras did not exist. It was all film, 16 mm film to be exact, with clunky cameras. That found me making friends with the people at Alvin’s camera shop, on Lake Street in Pasadena.

  Filming is not an easy enterprise. At the beginning, I didn’t know anything about filming: about lighting, f-stops, focus, depth of field, or keeping the object to be filmed in view. Most of all, I didn’t have any idea how much a Bolex camera cost! The people at Alvin’s camera shop taught me everything. They began by fixing me up with a hand-cranked Bolex 16 and a tripod. I started out easily enough. One of the questions that kept coming up whenever anybody heard about the work was, How were the patients affected in everyday life? So off I went to film patients doing everyday activities. One of the patients, N.G., lived in West Covina (about thirty minutes from Caltech), and her husband worked at a Ford factory. They lived quite well and had a lovely swimming pool in their backyard. One day I went out to see her and set up the camera by the pool. N.G. gladly swam a couple of laps. I then set up a shot of her sitting down on her couch and reading a newspaper, just like anybody else (Video 2).

  To get more sophisticated than this required another addition to the camera. You could attach a small motor that allowed you to “film” remotely. Thus, I could set the camera up on a tripod, direct it toward an aspect of the experiment, and control the camera while I was doing whatever had to be done in the experiment. These films proved quite dramatic.

  And of poor quality: I was definitely not an ace cameraman. What to do? My good fortune was that I had come to know Baron Wolman, a fantastic young photographer and a future founder of Rolling Stone. He somehow had become totally fascinated with the research (another in the growing list of nonscientists I was meeting who were interested in science) and was willing to lend me a hand. I asked if he would mind driving down to Downey with me to film W.J. doing a simple task on a tabletop. Baron didn’t mind and came along. That film has become one of the benchmark representations of split-brain research (Video 3).

  The film was clear and crisp. In it, W.J. was first requested to arrange a set of blocks that were part of the Wechsler Adult Intelligence Scale test bank. These were four blocks each colored differently on their six sides. The patient was shown a card with one of many possible patterns on it and was asked to simply arrange the blocks to match the pattern, commonly called the Kohs blocks. For reasons that are still not completely clear, the human right cerebral hemisphere is specialized for the kind of visuomotor function that enables someone to do this task. This would predict that the left hand, which gains its motor control from the right hemisphere, would be superior at doing this task. That is exactly what happened and is shown in the film. Lickety-split, the left hand assembles the blocks directly.

  The next scene shows the right hand trying to do the same task. The right hand gains its control from the left hemisphere, the one with language and speech. Yet, when it tried to assemble the four blocks to match the very same picture, it couldn’t do it. It couldn’t even get the overall organization of how the blocks should be positioned, in a 2x2 square. It just as often would arrange them in a 3+1 shape. It was amazing. And as the right hand was trying and failing, suddenly the more competent left hand would try to intervene! This was such a common occurrence that we had to have W.J. sit on his interfering left hand when the right hand was trying to do something.

  Finally, we ran a trial where we left both hands free to try to solve the problem. In that one sequence, a much larger picture of what split-brain research was ultimately going to teach us was revealed. In brief, one hand tried to undo the accomplishments of the other. The left hand would make a move to get things correct and the right hand would undo the gain. It looked like two separate mental systems were struggling for their view of the world. It was dramatic, to say the least.

  The entire Kohs block test grew out of two earlier efforts. First, there was clear evidence from earlier neurological studies that right hemisphere lesions impaired the ability to draw a picture with a three-dimensional perspective, such as drawing a cube. We first did this test very early on, and it was clearly the case with W.J. The left hand could draw a respectable cube. The right hand could not.

  Meanwhile, Bogen kept trying to convince us to do “standard neuropsychological testing.” Sperry and I didn’t see the point, but to his credit, Joe pursued the matter and writes about it convincingly:

  After Bill had recovered from his surgical ordeal (and was feeling better), he was eager to participate in some laboratory experiments. After some months a helpful social worker got in touch with a psychologist who occasionally tested clinic patients. She arranged some funding and he agreed to meet. He seemed to me not only quite elderly but actually quite infirm.

  I explained the patient to the psychologist and how interesting he was. I asked him, “Do you give the standard tests?” “Oh yes, the Wechsler.” I didn’t know much about the test, and neither did Mike, and he reluctantly agreed after some argumentation.

  “Old Daddy Edwards,” as I learned he was sometimes called around the hospital, acceded to our request.
He sat across a card table (part of his equipment) from Bill. Mike and I sat on the other two sides watching. The testing went along for an hour or so, somewhat tediously from our point of view, until Dr. Edwards pulled out the Block Design subtest. Bill pushed the blocks around somewhat ineffectually. Meanwhile Edwards was timing in his usual fashion and ended up with a zero score. I suggested that [Bill] use one hand at a time. Dr. Edwards objected because it was customary for subjects to use both hands. However, he was persuaded to try this momentarily, so we asked Bill to use only his right hand . . . while sitting on his left hand. . . . He had considerable success. Mike and I looked at each other as if we had caught a glimpse of the Holy Grail. “Now try it with just your left hand,” I asked. He was quite successful! “Now try the next pattern.” With his left hand he did the next one quite quickly. “No!” Edwards said. “He is supposed use both hands.” It was getting a little tense, because he insisted on doing it the standard way and we were anxious to further pursue our Grail. Dr. Edwards quietly prevailed, and he finished the tests. We thanked him, and he replied, “Yes, it was interesting. We should test 20 or 30 more of these epileptic patients with various lesions.” So this fumbling with the two hands seemed to be an example of what Akelaitis called “diagnostic dyspraxia,” which we had subsequently termed “intermanual conflict.”

  We realized Edwards was in the dark as to what had happened and what sort of patient Bill was, or why we were so wreathed in smiles. My next move was to borrow a set of these Wechsler blocks (one needed a license to buy them), and then I eventually obtained a set of the Kohs colored blocks. We retested Bill, and sure enough he had the same discrepancy between the left hand doing well, and the right hand doing poorly, and this persisted for at least 2 years. When we showed the data to Sperry he commented in his usual soft, skeptical way, “Well, I guess you boys have got that fellow pretty well trained by now.” It was true that not all patients showed this discrepancy. The second patient did not show this discrepancy, being actually rather poor at the test with either hand. However, some patients definitely did show the discrepancy.23

  Thankfully, in the late 1960s, soon after my Caltech days, the black-and-white reel-to-reel video cameras arrived. Combined with the recording unit, they were originally large and clunky, even though they enabled the video recording of experiments. Still, at least in the early days of video, something about “film” had video beat by a long shot. A few years later, when I moved to the State University of New York, Stony Brook, my entire start-up package went to purchasing a Beaulieu News 16, a 16 mm camera that recorded sound on the film. The silent movie era was over. We could actually hear what patients said in response to questions and queries of various sorts. I hauled that camera around in its fancy huge aluminum case for years, taking it to Paris and other places, feeling quite macho while doing so. Many years later it had become a burden to maintain and use, and it slipped off the inventory. A talented Dartmouth undergraduate was graduating and leaving for a life in documentary filmmaking in Brooklyn. I had it tuned up and gave it to him. It lives somewhere.

  As I have said, Sperry was about to become fully engaged. At my coming-out seminar, I had put together a fifteen-minute film of the patients doing their various things. First I showed them in everyday-life situations looking utterly normal in all ways. Next were various scenes of patients showing the disconnection effects, including not being able to speak about visual information projected into the left visual field. More important, I then showed scenes where that left-field information could nonetheless be acted upon with the left hand by finding a matching object from a group of objects. Finally, the film wound up with the segment of W.J. doing the block test I described. It was, to say the least, riveting: a showstopper. Everybody said so. That was a great day.

  I would describe the next day differently. It was tough. Sperry asked me to come to his office, and within minutes the grilling started. He challenged every finding as if he had not been following them closely, even though we had spoken for hours upon hours after each testing session, many of which he had attended. He went at it for a couple of hours. I was in shock. I didn’t realize for some time that he was doing the right thing. The fifteen-minute film really made the studies come to life, and he knew this was going to be a big deal. He wanted to make absolutely sure all the tests were done correctly. He had placed his bet and given his complete and unwavering support early on. Now he was going to really make sure the work was unassailable. He was doing his job, and I was still learning how it all worked.

  In the background was the ever-present Caltech culture, a culture that was all about inquiry. Richard Feynman, for example, had a way of popping into graduate students’ offices and asking them what they were doing. One day I was working away when the door opened up and there were Feynman’s crystal blue eyes. He asked, “So what are you doing?” I was deeply involved at that point with primate testing, an enterprise that was intense and costly. Building training devices for each monkey was getting expensive, and the overall data collection and analysis was clumsy. And there was the problem of monkey virus B, a deadly disease that could be communicated to humans by a monkey bite. So when Feynman asked me the question, I had a ready answer.

  “Well,” I said, “I am trying to build a device that we could implant in each monkey that would send out a radio signal identifying him. Then we could put all the monkeys in one big cage, have a testing platform at the end of the cage, and when the monkey hopped up to play the game, a computer would recognize which animal it was and keep the response data sorted out.” Or something like that.

  Feynman furrowed his brow and said, “I have a simpler system. Put the monkeys on a differential diet so each weighs a different amount. When they get on the testing platform, let a scale detect which monkey it is by weight and use that as a way to keep track of the data. No fancy radio transmitters and no implant surgeries.” He smiled, winked, and got up and left. I was stunned but soon got back to work. A few minutes later, Sperry walked into the lab as he often did. I told him the story, we chitchatted a bit, and he left.

  About thirty minutes later Sperry came back. He said, “It won’t work.” Puzzled, I asked, “What won’t work?” “Feynman’s idea,” he answered. “The animals will cheat and won’t weigh in properly. They will grab the cage bar when they swing in to work.” As Sperry left, I thought once again that I worked at the greatest place on earth, brimming with smarts and bristling with competition.

  WAIT: HOW DOES SENSORY-MOTOR INTEGRATION WORK?

  Seeing any one study now, with the knowledge under my belt that I have gained from hundreds of subsequent studies examining dozens of issues, puts me in mind of several brain mechanisms at work during a given test. During those early days, however, none of those mechanisms had been worked out. As Bogen pointed out, the other widely studied patients of the California series did not show the clear results on the block design test that W.J. revealed. What was up with that? What could possibly explain the individual variation of capacity seen in several patients? Individual variation always offers an opportunity to dig deeper into mechanisms, so it was back to work for me.

  In the lab at the time, everyone was fascinated with the problem of sensory-motor integration in cats, monkeys, and humans. We knew that each of the disconnected hemispheres best controlled the opposite arm and hand. Colwyn Trevarthen, a postdoctoral student at the time (who had also done his thesis work at Caltech), was carrying out a series of very clever experiments showing that in monkeys, use of one arm/hand responding on a task meant the opposite hemisphere would learn the problem. The ipsilateral (same-side) hemisphere, even though it had equal access to the information, did not learn. Switch the hand that was responding to the task, however, and quickly enough learning took place in the previously oblivious hemisphere. So, each hemisphere is really good at controlling the opposite arm/hand.24 That made tremendous sense with the underlying anatomy.

  The puzzle was, How did a hemisphere control the ipsilateral
hand, which some patients seemed able to do? In other words, how did a left hemisphere control the left hand? While W.J.’s individual hemispheres had little problem controlling the contralateral arm and hand, they were remarkably unable to control an ipsilateral arm and hand. This is quite a dramatic situation. Many of the original split-brain stories about two minds being in our skulls instead of one came from that clear linkage between each hemisphere and its contralateral arm. The film emphasized this basic finding, which was immediately evident to anyone testing the patient. As more patients were added to the study pool, however, many began to show good control over the ipsilateral arm as well as the contralateral arm. Yet, even when there was good control of the ipsilateral arm, good control over movements of the ipsilateral hand seemed to elude the patients. How did all of this work?

  It finally became apparent to us why all the patients did not show the same block design phenomenon as W.J., who was uniquely skilled with his left hand. Some of the patients had more control over their ipsilateral hands than did others. It usually took them a little time after surgery to learn how to control the ipsilateral hand, but most of them got really good at it. That meant that a hemisphere, specialized for a kind of processing that could be revealed by, say, arranging blocks, could, after it learned to control the ipsilateral hand, do it with either hand. Thus we could not tell which hemisphere was controlling the movements of the hands. This dual control made it exceedingly tricky to evaluate the special abilities of the left and right brains.