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

by Gazzaniga, Michael S.

  As if there weren’t already enough excitement in our New York lives, the field of medical brain imaging was emerging with such lightning speed and with such proximity to us, we were about to find out the answer. Of course, CT scans had been around for a few years. Their ability to detect tumors and other abnormalities in the head and body were already legendary. At the time, however, they could not detect the white matter—that is, the communicating nerve fibers—of the callosum and couldn’t help with our question.

  Yet, right on CT’s heels came the development of magnetic resonance imaging (MRI), the imaging technique that was going to transform medicine and, to some extent, the whole field of brain science. Once again, I knew nothing about that form of brain imaging, and, once again, the clinicians at New York Hospital were our enthusiastic teachers. Professors Gordon Potts and Michael Deck took us under their wing and, before you knew it, we were scanning our patients and determining if they were truly split.

  These were early days and, luckily, we were in the hands of pros. As fantastic as MRI was and would become, those on the forefront of the technique were feeling their way, trying to set the parameters of the scanner to obtain the best images for white matter. After much experimentation, Deck and Potts were ready. J.W., our star patient, slipped into the scanner. Would years of study have to be reinterpreted because J.W. was not fully split? Would he be as described by the neurosurgeon years before? The tension in the viewing room of the scanner was palpable, with Jeff adding that extra edge of angst.

  J.W. was lying quietly. The machine was banging away, as MRI machines do. (Put in the most simplistic terms, the machine works by sending out radio pulses to enliven water molecules in the brain. These newly activated molecules quickly relax back to their normal state. The device’s giant magnet picks up the change and the data is reconstructed to produce the brain image in the viewing suite.) Potts and Deck had chosen to view the first set of data in the sagittal view, a slice oriented from the nose to the back of the head. An image smack in the middle of the brain, exactly between the two hemispheres, should reveal a big black hole where the glistening, white callosum used to be.

  The images started to roll into the viewing room. They started on the right side of the brain and slowly made their way to the center cut we were looking for. It is quite a sight, magic almost. Everything that came before that key moment had been figured out by hundreds of scientists from multiple fields, building bit by bit over the years. To name a few, this included the help of exceptionally clever bioengineers and medics, who knew something about the body and the questions that needed to be asked, and computer scientists and physicists who figured out the calculations of unbelievable complexity that the computer was performing as we waited: cooperation on the grand scale. And, oh yes, living and working in a culture that encourages advances doesn’t hurt, either. It is a beautiful thing, when you pause for a moment to think about it.

  The images piled up one slice at a time through the brain, the recording parameters of a certain process called “inversion recovery” doing their job. The other nerve fiber tracts of the brain were visualized, the ones that should have been intact within the right hemisphere. As the images approached the midline, the white fibers were drawing themselves together to cross over the callosal bridge to the other hemisphere. We all held our breath: Would the fibers stop being visualized or would they continue across the bridge? Would parts still be crossing while others cut? Would there be splotches of white or would it be vast darkness? The image appeared.

  It was black as an eight ball, all of it. The callosum had indeed been completely sectioned. Even better, the smaller anterior commissure, the connection left uncut in the Dartmouth series of patients, was sitting intact in the blackness like the North Star. Jeff and I just stared at each other. It was unbelievable. Our baby, cognitive neuroscience, had taken another small step forward. Converging evidence was going to make us all better at our science.

  I can remember the radiologists asking if they had helped and if could they do more. There were great turf battles going on between radiology and neurology departments to decide who would manage the exploding scanner technologies. These discussions were based on the economics and tensions of medical school financing and how it is organized to get the bills paid: It has to look seamlessly organized to the public. Yet none of this affected us or the desire of the medical hierarchy to get exciting research done. Cornell was a world-class place and that was evident at every turn. So Jeff and I said yep, they had helped us quite a bit, and that we had two more patients we needed to study, P.S. and V.P.

  P.S.’s images retold the J.W. story. He looked fully split on the MRI scan, except for a small “nodule” in the posterior callosum. After hours of exploration by Potts and Deck, recutting the MR data in several different ways, they concluded the nodule was an artifact of the machine itself and not neural tissue in any way. As with J.W., the anterior commissure, the smaller neural bridge between each hemisphere, was easily visible in P.S.

  We also brought in Case V.P. from Ohio. She was becoming another star patient, and we needed to know her status. Years after she was studied at Cornell, she was also studied at Dartmouth. The Cornell studies showed that some fibers remained in what is called the genu of the callosum, the anterior—that is, forward—part that interconnects part of the frontal lobe. We also saw a suggestion of some spared fibers in the posterior callosum, a region we knew was rich with fibers that played a major role in the transfer of sensory information. The imaged connection was slightly forward of where it was known that visual information transferred between the hemispheres. We had not seen any evidence of transfer on our neuropsychological tests of V.P. for visual function, but we were concerned. From that day forward, we made a special effort to doubly examine and look for any transfer.

  After we had moved to Dartmouth years later, and MRI research had advanced, we checked V.P.’s callosum again and did another scan. A new methodology and a new team of scientists had come along. The methodology was diffusion tensor imaging (DTI), where an MRI scan could more precisely detect the presence or absence of nerve fibers. The brain imaging team was headed by Scott Grafton, one of the most talented brain imaging experts in the country. Probing the callosum, especially at the key places where we thought we had found sparing of fibers, it became clear that there were indeed no fibers in the posterior region. At the same time, the anterior fibers were real and could be easily visualized and tracked. This meant we had an opportunity to try to figure out what a small, isolated part of the frontal lobe fibers might be communicating between the hemispheres. But that comes later.

  Overall, human split-brain research, thanks to the new technological developments, was on much surer footing. Within a few years, the Caltech patients were also given MRIs, and the evidence was good that their callosums had been completely severed as well. There remains doubt, however, as to whether the anterior commissure had also been sectioned, as the imaging machine used was not the kind that always picked up its signal—according to the authors who published the findings. Still, the evidence was excellent for the field. For the most part, split-brain patients were indeed split.

  WORKING AND PLAYING

  Even with the fast-paced science, the development of a new field of science, and my first trade book,13 my social life also managed to stay apace, especially with Bill Buckley. During frequent lunches with Bill and his friends at his favorite Italian restaurant, Paone’s on Thirty-Fourth Street, plans were always being made. I told him he should have a screenwriter take a shot at one of his Blackford Oakes books and sell it to Hollywood. He said, great idea. I said I know a young playwright. He said he knew the agent Swifty Lazar. Quick as a flash Bill hired my friend, who was the husband of one of my neurology residents, and we were off to the races, sort of.

  My biggest success with Bill was introducing him to word processing and, as soon as they came out, laptop computers. He would come over to my Cornell office and sit down at my Digital wo
rd processor, a huge clunker by today’s standards, but a slick device in those days. He was amazed and, of course, wanted one for himself. That was soon followed by his fascination with a letter I wrote him from Ravello on my new Sonycorder, a small keyboard device equipped with a tiny tape cassette. It recorded your work, which was then made available to your secretary’s playback device. It seemed like a perfect device for travelers. I used it to write my first book, The Social Brain. Bill wanted it immediately, but that quickly gave way to other devices, which came so quickly that he finally got his own guru of electronics to help him. He was like that, and he was also always thinking of the other guy. After one of his office visits, he diagnosed me as too sedentary for my own health. He bought me a membership to the athletic facility around the corner from my office—One on One. All I can remember about the experience is my personal trainer kept explaining to me why some of my muscles were really sore after a workout. “The problem is, you never use those muscles, so they ache after a good workout.” If I never used them, I asked him, why was I trying to develop them?

  But I wasn’t completely sedentary. Charlotte’s brother, Walter Dabney, was a park ranger at Mount Rainier and soon to be the chief park ranger of the United States. He was always urging us to take a climb with him up to the top of the mountain; I finally agreed because Bruce Volpe and the professor of neurosurgery, Dick Fraser, wanted to go. Charlotte wanted to go. Charlotte’s sister wanted to go. Volpe’s then wife, Nancy, wanted to go. Walter said he would take us up, but not until all of us could run four miles in thirty minutes. This was going to take some time. Every morning for a few months, we ran up the East River from our apartment on Sixty-Third Street, until we met the mark. We were ready.

  The afternoon of our flight to Seattle, Fraser and I worked in a game of squash. He was an expert, I was a schlepper, but it was part of my new get-in-shape program. Toward the end of the match, one of my racquet swings went awry and hit Fraser over his left eyebrow. It started to bleed profusely. Fraser immediately said, “Don’t worry. I will throw some stitches on it and meet you at the plane.” After a couple of checkup phone calls, all was okay, and off we went, all of us arriving in Seattle a little after midnight and boozy. Were we really in any shape to scale the fourteen-thousand-foot mountain?

  The morning after our late-night plane ride, we woke up to see the peak of the magnificent Mount Rainier out of our windows. The park housing was at five thousand feet, so the air was crisp and unusually warm on that spring day. Charlotte and her sister were up early, merrily packing all our stuff into the backpacks. The packs full, they tightened the cords on top. Proudly, they stepped back and decided to try one on for looks. This is when we realized that we had made a mistake common to greenhorn backpackers: They could barely lift the packs! It soon dawned on us that we had another problem: We hadn’t run our eight-minute miles trussed with a sixty-two-pound backpack.

  Somehow, we left about noon and somehow all of us made it up to Camp Muir, a mid-mountain station at about ten thousand feet. It had taken us more than seven hours, in large part because of me. Being almost six feet, six inches tall and weighing in at 230 pounds without the pack, I was asked to bring up the rear of the climb. Another facet of backpacking is that the tall guy with the big pack always ends up carrying other people’s stuff, which adds to his weight. Walter and the others would form nice steps in the crunchy, early spring snow. The steps held for everyone but me. All were of normal size, but when I hit the steps, they broke through, causing me to have to lift my foot at least twelve inches high to get out of the hole and get ready for the next step. It just about killed me. I had to use some of those slacker muscles, and they let me know about it.

  We didn’t make it to the top. The team in front of us had had a bad accident. They were hanging on their safety lines down a crevasse, and two of their climbers had been killed. Walter was radioed that a helicopter was on its way to pick him up, and it was his job to get the bodies. “Why?” I asked. “Why risk your life for two people who are already dead?” “Because,” Walter, explained, “those are somebody’s sons, and they live in some congressional district, and that congressman votes for U.S. park funding every year. Anyway,” he added, “it’s the right thing to do.” Minutes later, he ran over to sort of a private side of the mountain, took a leak, and came back to await the approaching helicopter. Over the roar of the whirling blades, I yelled, “How can you pee at a time like this?” “Because,” he yelled back, “if the helicopter crashes, you want an empty bladder!” The people who make this country great are everywhere.

  Who knows where ideas originate? We do at least know that the more diverse our experience, the more fluid our mind. Out of our Mount Rainier adventure, hiking, traveling, and socializing with a neurosurgeon, a neurologist, and a bunch of rangers, who are by their nature, “just do it” guys, came an idea that was related to my new fascination with computers, optical digital recorders, and training. Why not build a gadget that would allow young neurosurgeons to practice their skills on what would amount to a flight simulator for surgeons? There was a medically oriented foundation that looked favorably on innovative projects, so why not give it a shot? We did, and the money rolled in.

  The task was to digitize a neurosurgical operation in real time complete with correct and incorrect moves, complaining anesthesiologists, mistaken adjustment, and even haptics—felt resistance to the control levers. The new technology permitted near-immediate access to all the video segments we had filmed, which were stored in digital files separate from the surgery video. This meant we could suddenly interrupt a seemingly normal operation with a visual crisis, like an unexpected bleed. We built it, we tested it, but the foundation, under the advice of outside consultants, withdrew their support. Of course, computer simulation is commonplace now. A passing interest and a passionate interest are two different things for sure. Still, the young program officer of that foundation, John Bruer, soon became the president of the James S. McDonnell Foundation and a huge supporter of our nascent field of cognitive neuroscience.

  MOVING ON, AGAIN

  A major priority was to spend every weekend in Shoreham, Long Island, where we had bought a fabulous and zany house that had been under continual reconstruction by its owner, Geysa Sarkany, a Hungarian architect with an enormous and restless talent. After we bought the house, we continued to work on it until it was right for us. It became the center of our emotional life for years, a place where my four daughters could bring their friends, put on plays, hang out, and live.

  Of course, living in New York City during the week, Long Island on the weekend, and needing to get to New England once a month led to many logistical challenges. It was becoming obvious another move for the family was imminent.

  CHAPTER 6

  STILL SPLIT

  I learned very early the difference between knowing the name of something and knowing something.

  —RICHARD P. FEYNMAN

  THE EARLY ENGINES OF COGNITIVE NEUROSCIENCE WERE NOW RUNNING STRONG, fueled by new methods of experimentation. MR images were everywhere: Amazing anatomical images gave researchers great confidence to claim whether a particular part of the brain was present or absent. Those of us who worked on white fiber tract systems, like the corpus callosum, were particularly exhilarated. Exact knowledge of whether nerve bundles were present (such as when fibers were inadvertently left intact) or absent allowed us to perform a fine-grain analysis to determine where in the nerve bundle information might be transferring between the cerebral hemispheres and just exactly what that information might be.

  Added to this was the phenomenal development of the field of human electrophysiology (the study of electrical phenomena involved in mental processes), which scientists had turned from ho-hum into an exacting science. Leading the field was none other than my old buddy from Caltech, Steve Hillyard. After Caltech, he went off to Yale and trained with one of the senior psychologists in the field, Robert Galambos. Together they were among the first to show h
ow the simple, doctor’s-office-ready EEG signal could be tailored to track the flow of information through the brain. They decided to start “averaging” the brain signals to see if a discrete brain response, when linked to perception and attention, could be detected.1 Put simply, they flashed a picture to a subject and then made a short recording (a few hundreds of milliseconds) of the EEG signal that was produced. They flashed it again and recorded another EEG response. After doing this several times they added up all the EEG responses and averaged them. They looked to see if a discrete response could be detected that was linked in time to the picture that had been flashed. It could. These became known as event-related potentials, or ERPs; with these, a thousand ships were launched. So, now we had MR letting us know about place and ERPs letting us know about the temporal aspects—that is, the timing of brain activity.

  A third churning in the field was the role of cognitive science. Sophisticated experimental psychologists were becoming more intrigued with the brain and, in particular, the human brain. Formally, the field of cognitive science advanced the idea that, contrary to what the behaviorists preached, we humans were not simply a big bag of stimulus/response associations. We had a “mental” life too. Not only was mental real, but it could be explored scientifically.

  Lastly, the field of functional brain imaging exploded. It had begun with positron emission tomography (PET) and, a few years later, was enhanced with functional magnetic resonance imaging (fMRI). At the time, this development was limited to a few large medical centers, such as Washington University, Harvard, UCLA, and a few others, especially in London, but its seeds were everywhere. People were eager to see where it would go. In the early days of the studies, the work was centered on the blood flow changes within specific neural systems while simple perceptual or cognitive tasks were performed. Everyone was stunned that any of these things could actually be demonstrated. The entire field swooned.