Areas of the brain that are active when people are daydreaming or sleeping, and quiet when they are engaged in a task, are imperfectly synchronized in people with autism and attention deficit hyperactivity disorder, researchers say.

Important language areas in the brain don’t show the expected patterns of connectivity when people with autism listen to speech, suggests a poster presented Monday at the Society for Neuroscience annual meeting in San Diego.

Mice missing a large protein at the junction between neurons show motor impairments, anxiety and increased social behaviors, according to a study in the American Journal of Psychiatry. The protein, postsynaptic density-95 or PSD-95, is part of a key molecular bridge connecting other proteins linked to autism.

Two new studies provide clues that may explain sex differences in autism prevalence. Italian researchers have found that injecting estrogen into the brains of young male mice reverses some of the structural and behavioral changes associated with low levels of reelin — a brain protein that has been previously implicated in autism — and the effects endure into adulthood.

Telling jokes allows children to connect with others, refine their language skills and develop keen imaginations. Because these are precisely the skills lacking in people with autism, studying humor in children with the disorder may give insights into their abnormal brain circuitry and even lead to therapies, according to a review published in the Journal of Child Neurology.

Damage to the amygdala — a region of the brain that regulates emotional processing — does not cause autism, according to a study of two individuals with lesions in the region. The study, published in September in the Journal of Neurodevelopmental Disorders, found that these individuals show no evidence of autism when given multiple diagnostic tests.

A five-minute brain scan can help diagnose developmental disorders including autism in young children, headlines blared last week. That may be true several years down the line, but I’d say it’s a pretty big exaggeration of the actual findings.

Researchers have uncovered an important molecular piece of a learning mechanism that occurs at the junction between neurons. The findings, which may help understand how the brain is disrupted in disorders such as autism, appear in the 24 June issue of Neuron.

Scientists have for the first time captured a dynamic picture of brain defects in young mouse models of fragile X syndrome. The findings appeared in June in the Journal of Neuroscience.

Mice engineered to carry a well-known risk factor for schizophrenia show disruptions in the connections between two brain regions that coordinate memory and learning. And these disruptions directly cause problems with working memory — the ability to actively hold information and to recall that information to make a decision, according to a study published in Nature.