In search of my own brain

Being inside an fMRI machine is definitely more unpleasant than it looks to be from the outside. The space itself is astonishingly small, and the sense of being encased in a huge piece of machinery unsettles more than you think it will. For my experiment Joy and her team have placed a small mirror above my eyes that enables me to see a sliver of the world outside the tube. This sliver lets me read the text that they've projected onto a screen, but it also prompts a surge of nausea as I first enter the scanner.

The fMRI machine is capable of capturing two types of images: conventional MRIs that are higher resolution but don't show specific activity in the brain, and then lower-resolution "functional" images that show the brain actually thinking. (Functional MRI images work because active areas of the brain require an increase in oxygenated blood, which creates a small but detectable disturbance in a magnetic field.) We begin with a round of conventional images of my brain, during which time the machine rattles ominously around my head. Then we move on to our little experiment, starting with the checkerboard pattern.

You can easily tell when the fMRI is in its "functional" mode because it emits an uncomfortably loud, high-pitched, pulsing tone. (Hence the earplugs.) When you're actually inside the scanner, it sounds like a truck backing up into your head. For the first forty seconds of "rest," I find myself incapable of thinking about anything other than the excruciating noise. When the flashing checkerboard appears on the screen, it occurs to me that this is like attending some kind of demonic performance-art happening -- a tiny, cramped space with strobing black-and-white images projected onto a screen, all accompanied by monotonous, piercing rhythmic tones.

But by the second iteration of the checkerboard stage, I start getting accustomed to the noise and the physical enclosure. I can see Joy smiling at me through the mirror, and the sound becomes more background noise than anything else. In fact, I feel comfortable enough that I start having difficulty shutting off my brain during the "rest" periods. First, I find myself thinking about ways that I could describe the setting, shaping the story of my fMRI experience while my head is still stuck inside the device. When I catch myself doing this, I smile in my dark tunnel. It occurs to me that this is one of those small examples of the brain's miraculous resilience and flexibility: you stuff your brain into a physical situation that should by all rights overwhelm it, and you tell it explicitly not to think of anything, and yet still it churns away in spite of everything. You couldn't imagine a more hostile environment for free associating, but here my brain was riffing away, as though I were daydreaming in the shade of an oak tree.

Then I'm reading. It ends up being easier to focus on my own words, but there certainly isn't time to ruminate. As we finish that stage, I think to myself that I'm glad we added the rumination "bonus round."

I'm glad, but I'm also getting tired. I haven't moved my head more than a centimeter in around twenty-five minutes, and the space is starting to close in on me. When the first frozen slide of text arrives on the screen for the rumination stage, I feel like I've been caught off guard. "Shit!" I say to myself. "Now I have to think of something." For forty seconds of this $2 million machine's time, I think of absolutely nothing worthwhile. I think about trying to think about something. If there is a cognitive version of flailing, this is what I do for the first scan.

But when the second round -- the last run of the entire experiment -- arrives, I'm prepared. I decide to let my brain do what had come naturally to it throughout the experiment. I've already started down the road of describing the experience in the scanner -- why not take this last round and actually start working out the language? And so when the text flashes up on the screen, notifying me that the forty-second rumination period has begun, a sentence starts to take form in my head. I am writing.

The words I string together in the fMRI are roughly the same words you encountered a few paragraphs ago describing the resilience of the brain in the most uncomfortable of situations. The general idea arrived a few minutes earlier, but the exact phrasing originates in that last session. The specific sentence, of course, is incidental; what makes it interesting is that Joy Hirsch and her fMRI are watching as it forms in my head, as my brain pulls the words out of the nothingness and makes them into something fixed -- sturdy enough to remain intact until I sit down at my computer several days later to type them.

Next Page: A snapshot of Johnson's brain getting its act together

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