Neurons that activate signals in a brain region important for language and imitation are smaller in the brains of individuals with autism than in those of controls, according to a study published 31 March in Acta Neuropathology.

Three independent studies presented in May at the International Meeting for Autism Research (IMFAR) in Toronto suggest that much of the brain in people with autism looks the same as that of controls.  The results contradict the so-called connectivity theory of autism, which holds that the brains of people with the disorder have weak long-range functional connections compared with controls.

The bundles of nerve fibers that connect two regions important for language are abnormal in the brains of children with autism, according to a study published 5 April in the American Journal of Neuroradiology.

The largest brain imaging study ever performed has identified candidate genes that influence brain size and general intelligence, according to research published 15 April in Nature Genetics.

Neurons lacking PTEN, an autism-associated gene also involved in cancer, are hyperconnected to both near and distant brain cells, according to a study published 1 February in The Journal of Neuroscience.

Children with autism have a smaller corpus callosum, a bundle of nerve fibers that connects the two hemispheres of the brain, compared with controls, and this difference persists over two years of development, according to a study published 18 February in the Journal of Autism and Developmental Disorders.

Rather than a tangled bowl of spaghetti, the neural wiring in the brain is arranged in an orderly fashion, like a woven piece of cloth, according to research published today in the journal Science.

Adults with autism have regional differences in brain volume in areas that play a role in social behavior and communication compared with controls, according to a large study published in the February issue of Archives of General Psychiatry. The differences correlate with the severity of autism symptoms, the study also shows.

A detailed brain imaging study of people with Williams syndrome, a developmental disorder characterized by a highly sociable personality, has found a series of structural, functional and connectivity deficits that converge on a part of the brain called the insula. The findings were published online 12 March in Proceedings of the National Academy of Sciences.

Brain imaging studies of people with autism show that specific areas respond more strongly to song than do those of controls. The opposite is true when listening to speech.