The Surprising Symmetry of Brains on the Autism Spectrum

MRI study finds brains of ASD subjects are more symmetrical than typical brains, which makes sense.


Though neurologists have debunked the old conventional wisdom that the human brain is cleanly divided into a right side for creativity and left for analytical thinking, it’s still the case that the two sides have their specialties. In most people the right hemisphere is denser with connections, but a new study of children and adolescents on the autism spectrum (ASD) suggests that the connections in their brains are more evenly distributed across the hemispheres than in others’.

(WALLYBIRD)

Language processing and speech are primarily handled in the left hemisphere of the brain, which also concerns itself with the processing of fine details. The right, on the other hand, works to integrate these details with other factors, including sensory input, and it’s also where auditory and visual sensory stimuli are processed. It’s assumed that the right hemisphere’s task of processing information from both hemispheres is the reason it has more connections than the left in the typical brain.

Neuropsychologists at San Diego State University’s Brain Development Imaging Lab used magnetic resonance imaging (MRI) diffusion tensor imaging to study the brains of 85 participants: 41 with ASD and 44 without. The were interested in seeing the density of brain connections throughout the brain’s white matter. The results were published in the Journal of the American Academy of Child & Adolescent Psychiatry December issue.

In typical developing brains, the scans did show that the right hemisphere had more densely-packed connections. “This fits with the idea that the right hemisphere has a more integrative function, bringing together many kinds of information,” the study notes.

The study’s MRI scans (RALPH-AXEL MÜLLER)

On the other hand, connections were more evenly distributed across the hemispheres of ASD brains. According to Ralph-Axel Müller, one of the study’s authors, “The idea behind asymmetry in the brain is that there is a division of labor between the two hemispheres. It appears this division of labor is reduced in people with autism spectrum disorder.” The study’s other authors are Ruth Carper and Jeffrey Treiber.

In people with ASD, it may be that the hemispheres are less specialized. While more study is needed, it seems like this fits with autistic people's enhanced skill with details and trouble with integrating these details into a larger picture, referred to as “weak central coherence” in the study.

One of the unresolved questions that will require further study is this: Is the symmetricality of ASD brains the cause of being on the spectrum or the result of autism?

LinkedIn meets Tinder in this mindful networking app

Swipe right to make the connections that could change your career.

Getty Images
Sponsored
Swipe right. Match. Meet over coffee or set up a call.

No, we aren't talking about Tinder. Introducing Shapr, a free app that helps people with synergistic professional goals and skill sets easily meet and collaborate.

Keep reading Show less

10 books to check out from Jordan Peterson's 'Great Books' list

The Canadian professor has an extensive collection posted on his site.

Jordan Peterson with Carl Jung and the cover art of Jaak Panksepp's 'Affective Neuroscience' (Image: Chris Williamson/Getty Images/Big Think)
Personal Growth
  • Peterson's Great Books list features classics by Orwell, Jung, Huxley, and Dostoevsky.
  • Categories include literature, neuroscience, religion, and systems analysis.
  • Having recently left Patreon for "freedom of speech" reasons, Peterson is taking direct donations through Paypal (and Bitcoin).
Keep reading Show less

Your body’s full of stuff you no longer need. Here's a list.

Evolution doesn't clean up after itself very well.

Image source: Ernst Haeckel
Surprising Science
  • An evolutionary biologist got people swapping ideas about our lingering vestigia.
  • Basically, this is the stuff that served some evolutionary purpose at some point, but now is kind of, well, extra.
  • Here are the six traits that inaugurated the fun.
Keep reading Show less

Should you invest in China's stock market? Know this one thing first.

Despite incredible economic growth, it is not necessarily an investor's paradise.

Videos
  • China's stock market is just 27 years old. It's economy has grown 30x over that time.
  • Imagine if you had invested early and gotten in on the ground floor.
  • Actually, you would have lost money. Here's how that's possible.