The Autistic Brain: Thinking Across the Spectrum Read Online Free PDF Page B

busted, weird stuff happens. Knock out your motion circuit, and you might see coffee pouring in a series of still images. Knock out your color circuit, and you might find yourself living in a black-and-white world.
    Autistic brains aren’t broken. My own brain isn’t broken. My circuits aren’t ripped apart. They just didn’t grow properly. But because my brain has become fairly well known for its various peculiarities, autism researchers have contacted me over the years to ask permission to put me in this scanner or that. I’m usually happy to oblige. As a result of these studies, I’ve learned a lot about the inner workings of my own brain.
    Thanks to a scanat the University of California, San Diego, School of Medicine’s Autism Center of Excellence, I know that my cerebellum is 20 percent smaller than the norm. The cerebellum helps control motor coordination, so this abnormality probably explains why my sense of balance is lousy.
    In 2006 I participated in a study at the Brain Imaging Research Center in Pittsburgh and underwent imaging with a functional MRI scanner and a version of MRI technology called diffusion tensor imaging, or DTI. While fMRI records regions in the brain that light up, DTI measures the movement of water molecules through the white-matter tracts—the interoffice communications among the regions.
     
The fMRI portion of the study measured the activation in my ventral (or lower) visual cortex when I looked at drawings of faces and drawings of objects and buildings. A control subject and I responded similarly to the drawings of objects and buildings, but my brain showed a lot less activation in response to faces than hers did.
The DTI scan examined the white-fiber tracts between various regions in my brain. The imaging indicated that I am overconnected, meaning that my inferior fronto-occipital fasciculus (IFOF) and inferior longitudinal fasciculus (ILF)—two white-fiber tracts that snake through the brain—have way more connections than usual. When I got the results of that study, I realized at once that they backed up something I’d been saying for a long time—that I must have an Internet trunk line, a direct line—into the visual cortex to explain my visual memory. I had thought I was being metaphorical, but I realized at that point that this description was a close approximation of what was actually going on inside my head. I went looking for broken-brain studies to see what else I could learn about this trunk line, and I found onethat involved a forty-seven-year-old woman with visual memory disturbance. A DTI scan of her brain revealed that she had a partial disconnection in her ILF. The researchers concluded that the ILF must be “highly involved” in visual memory.
Boy,
I remember thinking,
break this circuit and I’m going to be completely messed up.
     
    In 2010 I underwent a series of MRI scans at the University of Utah. One finding was particularly gratifying. Remember that when I pointed out the size difference in my ventricles to the researchers after my first MRI, back in 1987, they told me that some asymmetry in the brain was to be expected? Well, the University of Utah study showed that my left ventricle is 57 percent longer than my right. That’s huge. In the control subjects, the difference between left and right was only 15 percent.
    My left ventricle is so long that it extends into my parietal cortex. And the parietal cortex is known to be associated with working memory. The disturbance to my parietal cortex could explain why I have trouble performing tasks that require me to follow several instructions in short order. The parietal cortex also seems to be associated with math skills—which might explain my problems with algebra.
    Back in 1987, neuroimaging technology wasn’t capable of measuring the anatomical structures within the brain with great precision. But if those researchers back then knew that one ventricle in my brain was 7,093 millimeters long while the