Autism Spectrum Disorders and the Brain

"A lot of literature on autism says that the brain of a child on the spectrum is 'wired differently'. Can you elaborate of this difference?"

Over the past few years, a number of studies have been published linking differences in brain structure and function to Autism Spectrum Disorders (ASD). For example, researchers have noted that:
  • At a certain point in post-natal development, ASD brains are larger
  • Certain parts of the brain may function differently in ASD children
  • Certain portions of the brain, such as the amygdala, may be enlarged in ASD brains
  • “Minicolumns” in the brain may be formed differently and be more numerous in ASD brains
  • Testosterone may be linked to ASD
  • The entire brain may function differently in ASD children

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

In many ASD children, the brain develops too quickly beginning at about 12 months. By age ten, their brains are at a normal size, but "wired" differently. The brain is most complex thing on the planet, so its wiring has to be very complex and intricate. With ASD, 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 (i.e., small structures within the cortex) are also different among children with ASD. They 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 children. The result may be that children with ASD think and perceive differently and have less of an ability to block sensory input.

ASD really impacts behavioral function in the brain very broadly. It affects 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, ASD children are socially/emotionally far more delayed than anyone ever thought, even if they have a high IQ.

While social and communication skills may be compromised by unique wiring in the brain, other abilities are actually enhanced. For example, ASD children have a really excellent 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!

ASD children think differently because their brains are wired differently. They think logically and predictably, but differently. It's as if they're colorblind. You wonder why someone doesn't stop at a red light – because they can't see it. Teachers need to be taught this. When the teacher says, "Close your books and hop over to the door" …and the child hops, the teacher feels mocked. But she hasn't been mocked – she's been obeyed.

Understanding differences in the ASD brain may also provide hints for better communication. For example, since it may be harder for a child with ASD to process multiple ideas, or to multi-task, it makes sense to (a) say less, (b) give the facts, and (c) don't give a lot of tone of voice, gestures or distractions. You'd be surprised how many behavior problems are related to that. Remember that the child is dealing with facts, not concepts.

In ASD brains, circuitry is developing into adulthood – but it's not developing in the right way, and it stops developing too soon. With the right treatment, though, it can be pushed.

Animal scientist Temple Grandin has an extraordinary mind. Probably the world’s most famous person with autism, she “thinks in pictures.” Overall, the right side of her brain dominates. Grandin’s enlarged left ventricle is a sign of abnormalities in her left hemisphere, which typically handles language, and may account for the difficulties she has with processing words. To make up for this, the right hemisphere sometimes overcompensates, which can lead to special abilities in music, art, and visual memory. Grandin’s amygdala (the almond-shaped organ said to play an important role in emotional processing) is larger than normal. This is not a surprising finding because among other functions, this region processes fear and anxiety, which are emotional states often affected by autism. Her fusiform gyrus is smaller than normal – also not a surprise, since this region is involved in recognizing faces, which is a social skill that autism may disrupt.

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