Switched On

by John Elder Robison

  Take a moment to consider how tiny neurons are, and then imagine some of them with tiny fibres stretched three feet long. . . . That was hard to wrap my mind around, but Lindsay assured me it was true. “There are actually long stringy neurons reaching all over your body,” she told me. “They are so thin that they are little more than strings of molecules, carrying the chemical and electrical signals to run our bodies.”

  Her words made my mind flash back to my teenage years, when Little Bear and I were growing up together. We had shared a lot of geeky interests: I introduced her to electronics, and she turned me on to science fiction. I suddenly remembered a book she gave me—Ringworld by Larry Niven. In it, he described something called a Sinclair Molecule Chain, a fictional wire made up of incredibly strong strands of molecules. I fantasized that these brain wires were about that thin, and I marvelled at the parallel between science fiction and medical fact.

  The Ringworld analogy somehow comforted me, and Lindsay’s explanation didn’t sound very scary. But then a technician, whom I hadn’t noticed before, crept up beside me with wires and alcohol swabs. I knew what that meant! Alcohol and swabs were what doctors used before they broke out the scissors and scalpels, and that was not part of my plan. I must have looked alarmed because she continued: “Don’t worry. Erica is just cleaning your skin. Then she’s going to tape three electrodes to your hand, and we’ll use a monitor to pick up the signals from your muscle activations.” I relaxed again and let her stick the electrodes to my paw. It didn’t hurt, but I was still temped to growl softly and bare my teeth when she leaned close. I refrained.

  Truly, I was a model of good behaviour.

  Lindsay held the coil up to my head, and it felt cool on my scalp.

  “How do you know where to put it?” I felt a little like a condemned criminal who keeps asking questions to stall his execution, but I still wanted to know.

  “The motor cortex is in the same general area on everyone,” she answered. Then she traced a circle on my head with her finger. “It’s right here. I know about where to put the coil just by looking at you, and we’ll refine the location by testing. You’ll see. Okay, are you ready to go?”

  Nodding my assent, I prepared to be zapped. Pop! I heard the machine and experienced the jolt of energy. If you’ve ever stuck your finger in a wall outlet, you know exactly how it felt—with one important difference. Sticking your finger in the outlet provides a zap that doesn’t end till you yank your finger out. The zap of a TMS machine only lasts a few thousandths of a second. Still, that pop of electrical energy is unmistakable. You feel the energy level rise, and you feel it fall. It’s a sensation akin to what it might feel like to pluck a harp string inside your head. Lindsay said she’d heard it described as a woodpecker tapping your scalp, and I guess I agree. Then she flicked a switch and the TMS machine fired out two pulses in a rapid tap-tap. “A doublet,” I exclaimed, and Lindsay was startled. “You counted those pulses?”

  “Yes,” I said, “there were two.”

  Lindsay told me that most of the people she had studied could not distinguish the two quick pulses from one. She tried it again, with more pulses, and I still counted correctly. “That’s pretty surprising,” she said. “Those pulses were only separated by three-thousandths of a second.” Her reaction made me wonder if I had an unusual ability to distinguish pulses, or if I was just the first person to speak up about it. Counting the pulses had seemed perfectly natural to me, just as if I were counting the beats of a snare-drum roll at a musical performance. Then I thought, Only freaks count drumrolls, and I decided to keep quiet.

  Lindsay had no idea what to make of my ability to count fast pulses and didn’t know if it mattered. I was just paying close attention to everything, because I was in a strange new environment with no sense of what might be important.

  Later we would learn that my ability was a feature of autism. Some autistic people—like me—can count the beats in quick bursts of sound; while most people see fluorescent ceiling light as a continuous glow, in fact the light is flashing off and on 120 times a second. Many autistic people can see that, which explains why that type of lighting can be unsettling to some of us.

  Then there was the feeling of TMS. I was surprised to feel anything at all, because one thing they had offered by way of reassurance was that the brain doesn’t have pain receptors. And sure enough, what I felt in the chair wasn’t what I’d call pain—it was more of an awareness of energy being fired into my head. “There are plenty of nerves in your scalp and skull,” Alvaro explained, and I’m sure I felt the TMS pulse through them. But I also felt something deeper—a stirring as energy flowed into my brain.

  “I don’t know what to say about that,” Lindsay told me. “I don’t think most people feel that inner touch. I’ve had TMS done to me and I couldn’t feel anything inside.”

  But the feeling inside was nothing compared to what happened next. She turned the power up on the machine and fired it again. The pulse made my arm jump like a kangaroo, but she just nodded calmly and backed the power level down. The next pulse moved my middle fingers, as if they were making me grab by remote control. The third—according to Lindsay—was right on target. My index finger gave a single subtle twitch as the TMS coil fired. They had found the spot. “Seventy-two,” Shirley read the number to the lab tech, as she adjusted the power level. The next pulse was at sixty-five; then sixty.

  “Frankenstein,” I said, and she nodded and tried to look serious.

  And that was the strangest thing. I could hear each pulse, and I could feel a twitch in my head. But at 25 percent power, nothing at all showed in the fingertip electrodes, even though I felt the zap go into my head. At 40 percent, there was still nothing. We went up slowly: 60 percent, 70 percent, then 72 percent. Suddenly a blip appeared from my fingers: 75 percent, and my fingers popped like frog legs off a dinner plate.

  It was very curious. During a break, I called Dave, who said, “Great! Now you can remagnetize the strip on my credit card using your mind.” It didn’t occur to me that he was being sarcastic.

  Next we headed over to the MRI centre. I’d called Dave earlier that day to ease my anxieties about what to expect, but he’d neglected to mention that there would be a contraption to hold my head steady that resembled a football helmet with weights to hold it on the table and pads inside to keep my head from moving. He’d warned me that some people get claustrophobic, but I resolved to lie still and quiet as they slid me into the machine. “It may be easier if you close your eyes,” the technician said, and I did.

  “Are you okay in there?” The technician operating the machine had given me a button to push if things went wrong. I wiggled my feet to reassure myself that I wasn’t strapped down and could get loose if I needed to. I’d spent time hiding in drainpipes as a kid, but this place was warm, dry, and free of snakes and critters. I was sure I could do it.

  “Here we go.” I heard the technicians leave the room, and a moment later the machine started humming. It played a very unusual melody of screeches, buzzes, and clicks. Judging from the sound, large masses were moving all around me, but when I opened my eyes all I could see was smooth white plastic.

  “Almost done,” the voice said, and then I heard the door open. Seconds later, they were sliding me out of the machine.

  They’d shot 168 images of my brain, which I carried home on a computer disc that the technician handed me. “The doctor will look at the data and talk to you in a few days,” he told me. The prospect of more waiting wasn’t too thrilling, but there wasn’t anything I could do except look at the images myself. So that’s what I did.

  The brain scans were grouped in two sets with vertical and horizontal views. The horizontal set showed slices of my head from the top of my skull to the start of my neck. The vertical set showed slices from left to right, starting with the left ear and ending with the right. It was weird, seeing that level of detail inside my own head. It looked like they’d sliced me open and peered inside. The clarity
of the images was eerie.

  There was a bright round pearl at the top of my neck and a shadowy mass behind my temple. The longer I looked at the pearl, the brighter it seemed. What could it be? When I looked at the top view of my brain, one side was markedly larger than the other. Was that what people meant by “left-brained”? It was time to call an expert.

  “Bring the disc over here,” Dave said, “and we’ll look at it together.” Feeling alarmed, I hopped in my car right away. Arriving at his house, we put the disc in his computer, and I pointed to the images in question. “That’s not a pearl,” he said, laughing. “It’s blood. The MRI image slice shows it as bright white because it’s a shot of fresh unsaturated blood heading up from your neck into the scanner’s imaging field.” We turned to the other image, with the strange-looking shadow. “That’s your ear.”

  “See this?” He pointed to an image that showed the very substantial difference in size between the two hemispheres of my brain. “That shows that you didn’t have your head straight in the machine. One side looks bigger than the other because the slices are tilted.”

  His lack of bedside manner had been honed by years of practice and thousands of scans. Listening to him, I wasn’t sure if I should be relieved or disappointed.

  After I got home, Cubby found the disc and turned the MRI data into an animated brain on YouTube. That was the most I could get, until the folks from the lab called me back.

  “Everything looks good,” Alvaro said. “When do you want to start?”

  Returning to the lab a week later, I saw what they’d done with the MRI images. A large monitor sat on the tabletop beside the TMS machine. Its screen was divided into quarters, with the top left showing a circle with red crosshairs in the middle. The top right box showed my brain—all by itself in photo-realistic detail—suspended in space. Slightly to the right and below the brain I saw four red dots. “Those are the reference points—the bridge of your nose, the tip of your nose, and your tragus,” Lindsay said, pointing to the small cartilaginous bit of my ear closest to my head. I reached up and touched that part of my ear. “Ear points,” I said. She nodded.

  “See those cameras?” Lindsay pointed at two cameras, which gazed down at me from the intersection of the wall and ceiling. “We use this”—she picked up a sort of laser pointer—“to highlight those spots on your head one at a time, so the computer can match the position of your head as you sit in the chair to the model on the screen.”

  The bottom boxes showed MRI slices of my brain from above and from the side. On each slice a set of red crosshairs was visible. “That’s going to be our first target.”

  They fitted me with a headband that had three grey balls protruding from a two-inch-long shaft. “The cameras see the balls and the computer knows that the surrounding space contains your head. Now we’ll do the calibration.” She stepped over to the computer and started the calibration routine. The first point was my nose. Placing the dot on the tip of my nose, she looked over to see if the computer had picked it up. A soft beep signified success. Moving on, she touched a second point on my nose, then the tips of both tragi.

  I remembered what I used to tell my son when he was little and needed a haircut. “Cubby,” I’d say, “I’m going to take you to the barber and get your ears trimmed to nice sharp points like Mr. Spock on Star Trek.” As a result, Cubby had resisted haircuts for years. Now they were tagging my own ear points!

  With the system calibrated to my head they were ready to go. “We already calibrated the TMS coil before you arrived.” Looking over, I saw it had a three-ball setup similar to the one on my headband. However, the pattern was different, which allowed the computer to distinguish the TMS coil from my head.

  “Look,” Lindsay said, and I turned to the monitor as she held the coil against my head. She moved it, and I felt it glide around my scalp. As she did that, the crosshairs in the three brain windows shifted, and a blue dot moved around the top left box, way outside the target crosshair ring. Then she placed the coil in position, and I watched the blue dot glide right into the centre of the crosshairs.

  “How precise is it?” I asked. In response, she moved the coil a tiny bit and I saw the dot move off the crosshairs. “It’s got a resolution of about a millimetre,” she explained. I was impressed.

  Each of the MRI images—from both the vertical and horizontal series—was the same size and showed an area a bit bigger than my head in total. When you looked at the images you could see the skull, the scalp, and the faint outlines of my ears, nose, and mouth. They had gone into each image file and tagged the reference spots—points on my ears and the tip of my nose—one by one. That allowed a computer to put the data together and make a single three-dimensional model of my brain, in remarkable detail. All that was missing was my head. That was what I saw on the screen, marked with the target for the first stimulation.

  It was a very sobering moment. Hearing “We’re going to stimulate some regions in your brain’s frontal lobe” as an abstract phrase was one thing. It was something else entirely to sit there in the lab, look at that image of my brain on the computer screen, and see that blue dot marking the first target. It all suddenly seemed very serious.

  I don’t think Lindsay and Shirley had any idea of the cauldron of feelings that were stewing in me at that moment. I don’t even know if I could have described them. Wonder, curiosity . . . and a tiny bit of fear. But the thing that kept me going was hope.

  “We can target any point on the outside of your brain, and this will show us where to place the coil,” Shirley said with some pride. There was no question that they’d put a lot of work into modelling my brain. I hoped I wouldn’t screw up and disappoint them when they put it to use. I seemed to have passed their tests so far. The MRI didn’t show any missing pieces or extra stuff. Now that the mapping was done, things were about to get real. My first session was scheduled for the following week. I couldn’t wait to begin.

  The Night the Music Came Alive

  THE DAY OF MY FIRST TMS session started out like any other. I spent the morning at work, setting out for Boston in the afternoon. There was plenty of time to think during the drive out, and I tried to imagine what was about to happen and how my life might be different in just a few hours.

  I was a mass of roiling emotions when I reached the hospital. The next step—anticlimactic in the extreme—was another series of tests in front of a computer, led by Shirley and her assistant. “You will see a series of faces flash across the screen. Just push the button that corresponds to the expression you see,” Shirley told me. Left button for happy, right button for sad, with a third emotion in the middle. It sounded simple, but at the rate the images flew by, I had no clue what I was seeing. It was very frustrating, and I assumed there must be people who had the test down cold—otherwise, why do it? That realization made me sad; I felt like a failure before we had even begun, and my anxiety started gaining the upper hand over my excitement.

  They gave me another test. This time Shirley put a microphone in front of me and started a new computer program. In this exercise I saw objects and had to say what they were, as quickly as I could. Dog . . . house . . . car . . . tweezers. The objects were all familiar, but the sequence made the words seem weird. Scissors, cat, and airplane did not normally go together in conversation. This went on for quite a while, and I realized with a start that what they were testing was my ability to articulate what I saw. I wondered how changing that with TMS could possibly affect my life.

  “Don’t worry, that’s just the baseline. You did fine,” she said, as I sat with my tail between my legs. It all began to make sense—I’d do a test when I walked in, then they would zap me, and I’d do the test again. We all hoped I’d do better. For them it was academic. For me it was personal. Their tests and my beginner’s anxiety had me convinced I was a failure. What if they booted me out of the study? That would be the ultimate humiliation, especially for something as trivial as failing to recognize birds and hammers quickly eno
ugh.

  Finally we got down to it—the actual TMS. I’d experienced single pulses on my earlier visit, so I wasn’t particularly nervous. But the earplugs and mouth guards they offered me this time were a surprise and I wondered if they signalled unpleasantness to come. I’d read that the TMS pulses could cause facial muscles to twitch, which I guessed was the reason for the mouth guard. Refusing it, I agreed to use the earplugs, because the fan that cooled the TMS machine was pretty loud.

  Soon I was settled and the coil was in place. I thought of Alvaro’s explanation of how TMS can be configured to enhance or inhibit the areas it is fired into, and although all the TMS they did was inhibitory, he’d also drawn that analogy of the balance between the two sides of the brain. Depressing the right would stimulate the left. So what would I feel? Excitement, depression, or something else?

  Shirley stepped on the start button. The machine began humming, delivering one pulse per second in a smooth, steady rhythm that would last for thirty minutes.

  My proto-terror faded away with the first pulses. Nothing awful was happening. The pops reminded me of what I’d heard when we fired lasers, back when I worked at Candela. I felt a jolt of electricity that hit my head with every pulse—not enough to hurt me, but enough that I knew for absolute certain what it was. Anyone who’s been shocked knows the feeling—it’s unmistakable.

  Is that electromagnetic induction? That thought passed through my head, but almost as quickly as it arrived, it was gone. All that remained was the march of time, as defined by the coil. Pop. Pop. Pop. My head twitched with every pulse, but oddly enough, it wasn’t uncomfortable. It wasn’t really anything at all.