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Autism and the Brain

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Updated August 21, 2007


Recent Findings on the Autistic Brain

Over the past few years, a number of studies have been published linking differences in brain structure and function to autism spectrum disorders. For example… scientists have noted that:
  • At a certain point in post-natal development, autistic brains are larger.
  • Testosterone may be linked to autism.
  • Certain portions of the brain, such as the amygdala, may be enlarged in autistic brains.
  • Certain parts of the brain may function differently in autistic people.
  • "Minicolumns" in the brain may be formed differently and be more numerous in autistic brains.
  • The entire brain may function differently in autistic people.
To better understand which of these findings is legitimate and which is most significant, I interviewed Dr. Nancy Minshew of the University of Pittsburgh. Minshew is one of the most prolific and best-known researchers in the field of autism and the brain. According to Dr. Minshew, "These different theories are not all so different."

The Autistic Brain is "Differently Wired"

What all of these brain findings have in common, Dr. Minshew explains, is that they point to autism as a disorder of the cortex. The cortex is the proverbial "gray matter": the part of the brain which is largely responsible for higher brain functions, including sensation, voluntary muscle movement, thought, reasoning, and memory.

In many autistic people, the brain develops too quickly beginning at about 12 months. By age ten, their brains are at a normal size, but "wired" atypically. "The brain is most complex thing on the planet," says Dr. Minshew. "So its wiring has to be very complex and intricate. With autism there's accelerated growth at the wrong time, and that creates havoc. The consequences, in terms of disturbing early development, include problems within the cortex and from the cortex to other regions of the cortex in ways that compromise language and reasoning abilities."

Minicolumns, which are small structures within the cortex, are also different among autistic people. Dr. Manuel Casanova, a researcher at the University of Kentucky, has found that autistic people have more minicolumns which include a greater number of smaller brain cells. In addition, the "insulation" between these minicolumns is not as effective as it is among typically developing people. The result may be that autistic people think and perceive differently and have less of an ability to block sensory input.

The Down Side of Unique Wiring

If autistic brains are wired differently across the board, is it a problem? Of course, for many people -- and in many ways -- the answer is "yes."

Says Dr. Minshew, "Autism really impacts behavioral function in the brain very broadly. It effects sensory, motor, memory, and postural control -- anything that requires a high degree of integration of information. The symptoms are most prominent in social interaction and problem solving because they require highest degree of interaction." In fact, she continues, "They're socially/emotionally far more delayed than anyone ever thought, even if they have a high IQ. Temple Grandin, a well-known speaker and writer with autism, says she's emotionally about 7 - 10 years old."

The Up Side of Unique Wiring

While social and communication skills may be compromised by unique wiring in the brain, other abilities are actually enhanced. For example, says Dr. Minshew, "Autistic people have a really stellar ability to use the visual parts of the right side of the brain to compensate for problems with language processing. This may be the basis for detail-oriented processing -- and may be a decided advantage!" In fact, as she describes it, "Control children can't find Waldo. Autistic children can."

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