The Autistic Brain: Thinking Across the Spectrum by Temple Grandin, Richard Panek Read Free Book Online Page B

potential effect on the trajectory of an autistic person’s life.
    Just how young a person in the scanner can be depends in part on the technology. Functional MRI, for instance, requires responses to stimuli that create brain activity, so children need to be old enough (and, of course, to possess the neurological capacity) to understand the stimuli. Structural MRI, including DTI, doesn’t rely on brain activity, so it allows researchers to study subjects who are even younger—so young, in fact, that they might not exhibit behavioral signs of autism yet.
    That was the case in a 2012 DTI studyled by researchers from the University of North Carolina at Chapel Hill. The participants were ninety-two infants who all had older siblings diagnosed as autistic and therefore were thought to be at high risk themselves. Researchers scanned the subjects’ brains at six months, then followed up with a behavioral assessment at twenty-four months (as well as further scanning in most cases). At that point, twenty-eight of the subjects in the study met behavioral criteria for ASD, and sixty-four did not. Did the white-matter fiber tracts of one group exhibit any differences from the tracts of the other group? Researchers concluded that in twelve of the fifteen tracts under investigation, they did. At the age of six months, the children who later developed autistic symptoms showed higher fractional anisotropy (or FA, the measure of the movement of water molecules through the white-matter tracts) than the rest of the children. Usually that would be a good sign; a higher FA indicates a stronger circuit. But by age twenty-four months, those same children were showing lower FA, a sign of a weaker circuit. Why were those same circuits stronger at six months than those of the children who were developing typically? Were they even stronger even earlier? The researchers don’t have an answer, but they do have a new goal: three-month-olds.
    Another goal for further research is to look at the brain in even finer detail. Fortunately, the future is already here. I know, because I’ve seen it.
    Actually, I’ve been
inside
the future—a radically new version of DTI called high-definition fiber tracking. HDFT was developed at the Learning Research and Development Center at the University of Pittsburgh. Walter Schneider,senior scientist at the center, explains that HDFT was underwritten by the Department of Defense to investigate traumatic brain injuries: “They came to me saying, we need something that can do for brain injury what X-rays do for orthopedic injury.”
    When the research team posted a paperon the
Journal of Neurosurgery
’s website in March of 2012, the technology got a fair amount of media attention. The paper reported on the case of a thirty-two-year-old male who had sustained a severe brain injury in an all-terrain-vehicle accident. (No, he wasn’t wearing a helmet.) HDFT scans revealed the presence and location of fiber loss so precisely that the research team accurately predicted the nature of the lasting motor deficit—severe left-hand weakness—“when other standard clinical modalities did not.”
    “Just like there are 206 bones in your body, there are major cables in your brain,” Schneider says. “You can ask most anybody on the street to create a drawing of what a broken bone looks like, and they would be able to draw something somewhat sensible. If you ask them, ‘So what does a broken brain look like?’ most people—including researchers in the field—can’t give you the details.”
    Including researchers in the field? Really?
    “A fuzzy image of bones doesn’t give you a clean diagnosis,” Schneider says. “We took diffusion tensor imaging, and made it so it can.”
    While the focus of HDFT research so far has been on traumatic brain injuries, Schneider’s long-range plan is to map the information superhighways of the brain. For years I’ve compared the circuitry of the brain to highways, and I’m hardly