This is kind of neat. Scientists conducted several psychological and neuro-imaging tests on Temple Grandin — the woman who has used her own autism as a model for designing better livestock control systems. What they found is that Grandin's brain looks different, structurally, from that of a neuro-typical person.
Grandin's brain volume is significantly larger than that of three neurotypical controls matched on age, sex and handedness. Grandin's lateral ventricles, the chambers that hold cerebrospinal fluid, are skewed in size so that the left one is much larger than the right. "It's quite striking," Cooperrider says. On both sides of her brain, Grandin has an abnormally large amygdala, a deep brain region that processes emotion. Her brain also shows differences in white matter, the bundles of nerve fibers that connect one region to another. The volume of white matter on the left side of her brain is higher than that in controls, the study found.
Grandin isn't the only person with autism to have had their brain scanned. But the differences that have been found aren't always consistent from one study to another. That, of course, makes some sense, given the fact that the word "autism" encompasses a whole spectrum of differences and disabilities which may or may not represent one single thing. But there have been several studies that did find differences similar to the ones found in Temple Grandin.
And here's the really interesting thing. Some scientists think that the common differences we do keep seeing — especially the bit about the larger brain volume — might be a clue that what eventually becomes autism actually begins in the womb. Here's a quick excerpt from a story that Carl Zimmer wrote about this stuff last spring:
When autistic children are born, Courchesne's research suggests, they have an abundance of neurons jammed into an average-size brain. Over the first few years, the neurons get bigger and sprout thousands of branches to join other neurons. The extra neurons in the autistic brain probably send out a vast number of extra connections to other neurons. This overwiring may interfere with normal development of language and social behavior in young children. It would also explain the excess brain size seen in the MRI scans.
Special thanks to GrrlScientist!