Autism and the Brain: Recent Results from Brain Imaging Studies

A recent review paper by Minshew and Keller looks at progress understanding autism and autism spectrum disorders using functional magnetic resonance imaging (fMRI) studies and functional connectivity fMRI (fc-fMRI).

(The paper is titled “The nature of brain dysfunction in autism: functional brain imaging studies” and was published April 2010 in Current Opinion in Neurology.)

Studies using fMRI correlate heightened brain-region activation with particular behaviors. The more recent technique of fc-fMRI enables the researcher to correlate the ability of one brain area to active another area with particular behaviors. It seems that some of the most exciting new insights into autism have been gained using fc-fMRI.

Some of the findings discussed include:

  • Autism as a distributed cortical systems disorder resulting from the underdevelopment of connections between brain regions.
  • Structural imaging has shown accelerated brain growth beginning by 9–12 months of age coincident with the onset of symptoms and composed of increased total cerebral gray and white matter volumes.
  • Connections between the front and back (frontal-posterior regions) of the brain were commonly found to be less than normal in the autistic brain.
  • A study demonstrated the potential to increase connectivity in the autistic person. Ten weeks of reading intervention in poor readers resulted in improved reading and measurable changes in connectivity and white matter volume.
  • It’s easy to overestimate and exceed the language skills of a verbal person with autism. Although the autistic person may use the same words, their brains are wired differently. They show a greater reliance on visuospatial skills and the visual areas of the brain for solving both visual and verbal problems and reduced activity in the brain’s language areas.
  • When shown a movie, the brain in a person with autism perceived a different movie from other people with and without autism. The same person with autism saw a somewhat similar movie each time they viewed the same movie.

In summary, the review paper by Minshew and Keller demonstrates clear progress in elucidating differences in structure and function of the typical brain from the brains of people with autism. Perhaps most exciting is that studies are appearing suggesting interventions based on our new knowledge.