Here I am in the TMS lab at Boston's Beth Israel Deaconess Medical Center, with Lindsay Oberman, Phd holding the TMS coil over my head. I'm wearing a cap that has 32 EEG wires in it for brain wave monitoring. And the wires on my hand are picking up tiny electrical signals from the nerves in my thumb and forefinger. It looks kind of nasty but it's actually not uncomfortable at all. There are no holes drilled in me.
You can see the TMS machine behind Lindsay. There's a camera system and monitor out of sight in front of us, telling Lindsay exactly where to place the TMS coil. Behind us there is another computer monitoring brain wave activity throughout the test. In the corner there is a wet or dry shop-vac, in case my head explodes.
Yesterday I went to Boston to participate in this new TMS study. TMS (Transcranial Magnetic Stimulation) uses powerful focused magnetic fields to induce tiny signals in the brain. These TMS signals can cause permanent changes in our brains by showing us new paths between the neurons in our heads. TMS is currently used to treat depression, and it shows tremendous promise for autism, epilepsy, and a number of other conditions.
Perhaps one day it will even fix me. However, today’s study was not aimed at repairing the way I think. Rather, the goal was to evaluate the plasticity of my brain by measuring the circuits that operate my hand. That may seem mundane, but it’s actually really important. Studies like these are showing that people on the autism spectrum have more plasticity than neurotypicals, and that difference may be instrumental in shaping our lives.
Plasticity is the brain’s ability to form new paths. You might say it’s an essential component of learning any new skill. For example, when you learn the way up the stairs and down the hall to your room, you are using plasticity to make a path in your brain that tells your legs what to do to go from the front door to your nest.
The scientists in the TMS lab believe unusual plasticity is the reason I can learn things so fast. There have been many times that I’ve focused intently on some bit of arcana and become an expert so quickly that other people thought it was unbelievable. It’s kind of neat to hear an explanation for that, because I lived so much of my life with people dismissing my abilities as “lucky guesses,” or “getting away with something,” just because they could not relate.
To hear that greater-than-usual brain plasticity makes that possible is kind of neat. But I’m afraid it’s not the whole story. Sure, if I get fascinated by something I devour all I can about my new interest overnight, but there are plenty of topics that don’t interest me much, and plasticity does not help me one bit if I have to study them. Is plasticity a kind of fair weather friend, something that only helps with things I like?
Maybe. I don’t know, and I’m not sure that anyone else knows either.
It’s also not clear why plasticity would give me a great gift – speedy learning – while totally disabling other people on the spectrum. The scientists theorize that excess plasticity may leave some autistic people in a state of permanent confusion because the paths in their heads are constantly shifting. Nothing stays the same.
Why would some people be disabled by this, and others gifted? No one knows. Perhaps we’re totally wrong, or perhaps there are other factors at work. The more I learn about this work, the more I see how unfathomably complex even the simplest brains are. Today's science is far from unraveling the mental secrets of a mouse; they are just scratching the surface with creatures like me.
All brains have some amoount of plasticity, since it's essential to learn new skills. It's just a matter of degree. It’s possible that some parts of my brain are exceptionally plastic, and others aren’t. So maybe the distribution of plasticity makes a difference or explains why some parts of me are really smart wile others are pretty oblivious. Future studies may help answer that question.
Until then, we can just ponder how it is that plasticity can confer both genius and profound disability, perhaps even in the same person. I told you how scientists at the lab attribute much of my learning ability to plasticity. At the same time, they blame my social blindness in part on plasticity too. Dr. Lindsay Oberman – the scientist conducting this study – explained.
Neurotypical people might have one path in their heads to recognize facial expressions. By the time they grow up, that path is well worn and familiar. People with high plasticity (referring to me) might have a hundred paths, or a thousand, and they are all smaller. So plasticity has put a lot more options inside our heads, but they are so complex that they don’t run fast like an NT person. The result – a social disability.
What a paradox.
And now we get to the good part . . . plasticity may be changeable. Some brand-new studies have suggested that TMS can change the plasticity of parts of the brain. And other studies are exploring the possibility of using drugs to change plasticity. So we may be on the brink of being able to reduce plasticity in people who have too much.
But what will that mean?
If plasticity is the explanation for my social disability and exceptional focus and learning, I’d stay just the way I am, thank you. However, not all autistic people share my gifts. If I saw myself as more disabled than gifted, I might well make a different choice with respect to plasticity. If I could take a pill and watch my disability fade as my brain build strong pathways that would be almost magical. But would it play out that way? No one knows.
It’s possible we’d have to change plasticity in early childhood to make a dramatic difference. In that case, parents would have to make a life-changing treatment decision before they really knew the extent of their child’s future gift or disability. And by choosing less plasticity, they might be saying “NO” to the possibility of exceptional skills or creative genius. Or maybe not. Again, no one knows.
Parents and doctors may be facing some really tough choices soon, if these drugs and therapies pan out. For the only way to know what will happen is to try them on kids. Are you ready to line up?
That’s got to be a really hard choice to face. Especially when no one fully understands what may change. I guess that’s what science is about; hunting the answers to these questions.
Wednesday, December 16, 2009
Here are some of my other TMS autism stories:
Posted by John Elder Robison at 11:28 AM