On the Bookshelf: Thinking about thinking
In a class aptly named "gross anatomy," during her first few weeks of medical school, Shannon Moffett got her first good look at a human brain. She was dissecting a cadaver and remembers that the dead brain was murky brown, and "firm, like a block of cheese."
That's far different from the pink, lucent organ in the living body. "Imagine being a neurosurgeon," she writes in her new book, The Three-Pound Enigma (Algonquin Books). "There you are, staring at the slick white surface of [skull]...knowing that just inside, right up against the wall of that box, is the very self of your patient, embodied in a structure as delicate as custard." Thoughts, memories, behavior, and personality are in there somewhere, contained in 3 pounds of exquisitely connected cells poised in a bony bowl at the top of your neck.
But exactly where in those few pounds of flesh do those thoughts and memories lie, and how do they lie there? Moffett wondered. So she took time off from medical school to write a book and find out. By talking to top scientists and doctors who share her fascination, she explores such mysteries as the way memories form, what dreams are made of (and why dreaming about video games seems to make people better at playing them), and why certain people seem to have a "Jennifer Aniston neuron."
What is so interesting, and enigmatic, about the brain?
I think there is absolutely nothing more fascinating than this thing that, after all, contains our ability to be fascinated. It's really easy to say, "It makes us think and move." But when you start to dissect it, you run up against a wall of confusion. How does anybody know a thumbs-up is a positive sign? How do molecules race around in there to make us think? And presumably, if we could better understand what makes us behave and think, we might have a slightly better society. At least that's my utopian hope.
Can we understand what makes us behave and think?
Oh, the brain is such a vast, unexplored territory. But now we're getting these little encampments of knowledge around it. With new brain scans like PET [positron emission tomography] and fMRI [functional magnetic resonance imaging], we are starting to understand where in the brain certain tasks occur.
Like consciousness?
I said "starting" to understand. Consciousness is pretty big; there are some scientists who think it's too big to even ask questions about it. But there are other scientists, like Christof Koch of Caltech, who are using brain-scanning techniques to find single neurons that appear to be "conscious" of particular things.
So you start off with a huge question like 'What is consciousness?' and you end up with one single neuron? That's hard to believe.
Well, the late Francis Crick—the codiscoverer of DNA's structure who later worked with Koch—would say that the biggest questions need to be grounded in the smallest pieces. I talked to him for this book, and that's how he and James Watson went about understanding DNA and won the Nobel Prize for it. In this case, the brain, the smallest piece is a neuron.
The "Jennifer Aniston neuron"?
That seems ridiculous. But Koch is mapping the firing of single neurons. He works with epilepsy patients who, before they have surgery, need to have really detailed electrical maps of their brains made to locate their seizures and locate normal brain areas. Koch shows people a photo of Jennifer Aniston, and one neuron fires at it. And doesn't fire at anything else. They don't fire at photos of blondes, or girls with cute noses. Only Jennifer Aniston.
He also found a Bill Clinton neuron. And that's really surprising, because you shouldn't be able to have neurons dedicated to one thing. We have 100 billion neurons, but we have more than 100 billion experiences during our lives. Yet there it is. That has something to do with consciousness, though we don't fully understand it.
What do dreams have to do with thinking and consciousness?
Most of us like to believe our brains don't trick us. We live our lives based on this idea that we experience things as they are. But dreams are incontrovertible proof that our brains do trick us. When we have them, they demand all our attention. They are ecstatic and terrifying. And we all do it—we all dream. So it must be necessary and important.
So why do we dream?
There have been long debates about that. Some researchers think they are ways of dumping wakeful experiences we don't need. Others think they are a way of processing experiences, kind of rehearsing our reactions to them so we can better cope with them. I spoke with one researcher, Bob Stickgold of Harvard, who may have evidence of this. He's identified this phenomenon: hallucinations as we drop off to sleep after practicing a new skill. He studied people playing Tetris, the computer game where you have to fit different-shaped blocks into a wall very quickly. And going to sleep—this has happened to me; I was a Tetris addict—you can't get pictures of these Tetris blocks out of your head. They keep falling, and you keep turning them to fit them in. Bob has also shown this happens with a skiing simulation game called Alpine Racer. Maybe this is a way our brain can rehearse things so we can better perform them when awake.
That's perhaps a continuity between our waking and sleeping selves. But there are other states of mind you explore that don't even have continuity among oneself: multiple personalities.
They don't call it that anymore. David Spiegel, a psychiatrist at Stanford, told me, "We changed the name because they don't have more than one personality. They have less than one." It's fragmented. Now it's called dissociative identity disorder.
A lot of people don't think it exists. That such people are just putting on an act to get attention.
It's certainly a hot-button topic. And I'm not 100 percent convinced. But I spent a week with this middle-aged artist on Long Island in New York, Judy Castelli, and I watched her shift from one personality to another. It was all pretty normal, except for this dramatic switching. She suddenly started talking like a child. She told me that at one point she had 44 personalities, but she thinks that after years of therapy, that number has dwindled a bit. Three or four of them were adult Judys, she said, and some are more comfortable talking about mental illness, and some are more shy.
You believed her?
Of course I doubted her! But then, how could something like that appear real? Watching a grown woman curl up into a small ball on a couch and talk like a little girl has to seem like acting. But then you have to ask yourself something else: Why would somebody fake this for their entire life? Attention? The rewards are so tiny, compared to the costs. The illness has made her life miserable. Maybe it is possible to have more than one mind or a fragmented mind. Hasn't anyone ever said to you, "You don't seem like yourself today?" What's that all about?
What did you take away from your visit with Castelli?
First is the tremendous suffering any mental illness wreaks on the person and the people around them. And also that there are very practical ramifications to those big questions asked in the book, like "What is consciousness?" Here is a consciousness that's not quite working right. Her illness is evidence of how little we know about this 3-pound enigma.