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normal overall and have differences in specific regions similar to those seen in people with the disorder, according to unpublished research presented Wednesday at the 2011 Society for Neuroscience annual meeting in Washington, D.C.

Connections between the amygdala — a deep nub involved in processing emotions — and other parts of the brain are more numerous in children than in adults, according to unpublished research presented at the 2011 Society for Neuroscience annual meeting in Washington, D.C.

In high-functioning adults with autism, the signal-to-noise ratio in the outer regions of the brain is significantly lower than in healthy controls, according to unpublished research presented Friday in Washington, D.C.

Children with autism have an abnormally large number of neurons in the prefrontal cortex, a brain region important for abstract thinking, planning and social behaviors, according to a study published yesterday in the Journal of the American Medical Association.

Researchers have defined anatomical boundaries that minimize errors in brain-imaging measures of the amygdala, a region involved in emotion processing.

Girls with autism have more brain matter than do either controls or girls with developmental disabilities. This defect is particularly pronounced in the left superior frontal gyrus, a region in the medial prefrontal cortex that is responsible for higher-order cognitive function.

Autism studies tend to focus on one part of the spectrum, often excluding those who also have other conditions such as anxiety, obsessive-compulsive disorder or intellectual disability. The result, some experts say, is piecemeal findings that don’t fit together to generate a whole picture.

In the past year, several studies have suggested that brain scans will soon help clinicians diagnose autism. But many experts say these scans are far from — and may never be — ready for use as diagnostic tests.

A new method can distinguish between sub-regions of the amygdala, the deep nub of tissue that is involved in emotion processing and that shows abnormal activity in people with autism, according to a study published in the June issue of NeuroImage.

Family support groups may be the best messengers to convey the urgent need for brain tissue in autism research, say scientists struggling with inadequate resources.