A partial mutation that leads to a milder form of fragile X syndrome causes deficits in learning and memory in mice, and alters the connections between their neurons, according to a study published in January in Neurobiology of Disease.

The ‘intense world theory’ says autism stems from hyper-sensitive reactions to the world, allowing the individual to zoom in on tiny details, but ignore the bigger picture.

People with autism take longer to decide whether emotionally ambiguous facial expressions are positive or negative — and are more likely than healthy controls to choose the latter, say researchers who reported their results in a poster Sunday at the Society for Neuroscience annual meeting in San Diego in San Diego.

A Pittsburgh group has created a comprehensive database of brain scans and other medical and demographic data from nearly 800 individuals whose brains have been injured by strokes. The researchers showcased the collection, called the Western Pennsylvania Patient Registry, at a poster session yesterday at the Society for Neuroscience annual meeting in San Diego.

A new mouse model for Rett syndrome shows that disrupting a single brain messenger can produce nearly all of the characteristic features of the syndrome, researchers report today in Nature.

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.

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.

For nearly 20 years, Ralph Adolphs has been trying to figure out how the human amygdala works. An avid outdoorsman, Adolphs has run a dozen 50- and 100-mile races, and his colleagues say he approaches science with the same stamina and intensity. He has already published more than 100 scientific papers, several of them revealing intriguing ties between the amygdala and autism.

The amygdala, a brain region that regulates fear and anxiety, shows abnormal neuronal signaling in a mouse model of fragile X syndrome, according to two studies published this summer. These are the first to explore cellular defects in the region in fragile X.

Researchers have pinpointed the brain circuits that underlie the vasopressin hormone’s role in regulating emotions.