Mutations in more than 100 autism-associated genes lead to shared neurobiological deficits in mice, including alterations in the shape of their brains and changes to the electrical properties of neurons, according to a study published 20 February in Molecular Autism.

Dysregulation of the intracellular signaling pathway RAS, a risk factor for idiopathic autism, may provide a unifying theory of the disorder. Although this is not an altogether new hypothesis, several new findings have strengthened the evidence for it considerably.

The brains of men and women with Asperger syndrome are more similar than are those of male and female controls, according to a study published in the January issue of the American Journal of Neuroradiology. The results lend support to the ‘extreme male brain’ theory of autism, the researchers say.

Autism and attention deficit hyperactivity disorder show genetic and neurobiological overlap, which may provide clues to the origin of both disorders, says Joel Nigg.

The results of two new studies support recommendations against the use of brain scans to diagnose autism.

Scanning children’s brains while they sleep is a viable alternative to sedation for infants and toddlers across the entire autism spectrum, according to a study published in the January issue of the Archives of General Psychiatry.

A mouse model of Rett syndrome that mimics a mutation seen in people shows many features of the disorder, such as hand clasping, according to a study published 27 November in Nature Neuroscience.

Larger brains may be associated with regressive autism, but only in boys, according to a study published online 28 November in the Proceedings of the National Academy of Sciences.

Toddlers with autism who have larger-than-normal heads are also taller and weigh more than controls, according to a study published in October in Archives of General Psychiatry.

The brains of mice that model Rett syndrome are smaller than normal overall and have differences in specific regions similar to those seen in people with the disorder, according to unpublished research presented Wednesday at the 2011 Society for Neuroscience annual meeting in Washington, D.C.