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

of the anatomical structures inside the brain. Structural MRI helps answer the What does it look like? question.
    Functional MRI, which was introduced in 1991, shows the brain actually functioning in response to sensory stimuli (sight, sound, taste, touch, smell) or when a person is performing a task—problem-solving, listening to a story, pressing a button, and so on. By tracing the blood flow in the brain, fMRI presumably tracks neuron activity (because more activity requires more blood). The parts of the brain that light up while the brain responds to the stimuli or performs the assigned tasks, researchers assume, provide the answer to the What does it do? question. Over the past couple of decades, neurological research using fMRI studies has produced more than twenty thousand peer-reviewed articles. In recent years, that pace has accelerated to eight or more articles
per day.
    Even so, neuroimaging can’t distinguish between cause and effect. Take one well-known example associated with autism: facial recognition. Neuroimaging studies over the decades have repeatedly indicated that the cortex of an autistic doesn’t respond to faces as animatedly as it does to objects. Does cortical activation in response to faces atrophy in autistics because of the reduced social engagement with other individuals? Or do autistics have reduced social engagement with other individuals because the connections in the cortex don’t register faces strongly? We don’t know.
    Neuroimaging can’t tell us everything. (See sidebar at the end of this chapter.) But it can tell us a lot. A technology that can look at a part of a brain and address What does it look like? and What does it do? can also answer a couple of bonus questions: How does the autistic brain look different from the normal brain? and What does the autistic brain do differently than the normal brain? Already autism researchers have been able to provide many answers to those two questions—answers that have allowed us to take the behaviors that have always been the basis of an ASD diagnosis and begin to match them to the biology of the brain. And as this new understanding of autism is harnessed to more and more advanced neuroimaging technologies, many researchers think that a diagnosis based in biology is not just feasible but near at hand—maybe only five years away.
     
    I always tell my students, “If you want to figure out animal behavior, start at the brain and work your way out.” The parts of the brain we share with other mammals evolved first—the primal emotional areas that tell us when to fight and when to flee. They’re at the base of the brain, where it connects with the spinal cord. The areas that perform the functions that make us human evolved most recently—language, long-range planning, awareness of self. They’re at the front of the brain. But it’s the overall complex relationship between the various parts of the brain that make us each who we are.
     
    The human brain, side and overhead views.
    © Science Source / Photo Researchers, Inc. (top); © 123rf.com (bottom)
     
    When I talk about the brain, I often use the analogy of an office building. The employees in different parts of the building have their own areas of specialization, but they work together. Some departments work closer together than others. Some departments are more active than others, depending on what the task at hand is. But at the end of the day, they come together to produce a single product: a thought, an action, a response.
    At the top of the building sits the CEO, the prefrontal cortex—
prefrontal
because it resides in front of the frontal lobe, and
cortex
because it’s part of the cerebral cortex, the several layers of gray matter that make up the outer surface of the brain. The prefrontal cortex coordinates the information from the other parts of the cortex so that they can work together and perform executive functions: multitasking, strategizing, inhibiting impulses,