Mice with elevated levels of the immune molecule interleukin-6 have abnormally large brains, according to a study published 23 August in the International Journal of Neuroscience.

The action of certain maternal antibodies on the fetal brain may underlie the large brain size seen in some children with autism, according to preliminary findings from both monkey and human studies presented at a conference in Boston last week.

Knocking out an autism-linked gene called PTEN only in neural stem cells of the hippocampus, a brain region central to learning and memory, throws the development of new neurons off course in adult mice, according to research published last month in the Journal of Neuroscience.

By creating genetically engineered fish, two independent groups have identified genes in an autism hotspot on chromosome 16 that influence head size and brain development. 

Autism and antisocial disorder are separate conditions, with distinct differences in underlying brain structure, according to a neuroimaging study of the general population. The results were published 4 April in The Journal of Neuroscience.

Individuals with autism may belong to one of four groups with discrete sets of symptoms, the most distinct of which includes immune system abnormalities accompanied by sleep problems and sensory sensitivity. The results were published in the April issue of Autism Research.

Postmortem brain tissue from people with autism shows differences in the expression of genes involved in a number of molecular pathways, including those that control cortical patterning, programmed cell death and differentiation, according to research published last month in PLoS Genetics.

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.

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.

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.