A glowing protein tracks serotonin levels and location in the brains of living mice and could yield clues to the neurotransmitter’s role in autism.

Our staff picks the stories, podcasts and special reports that stood out from the rest this past year.

Autistic people have distinct patterns of brain development, which sometimes result in differences in brain structure. Here’s what we know about those differences.

Nearly all genes with moderate to strong ties to autism are expressed in the developing amygdala; a few show altered expression in the amygdalae of autistic people.

The amygdala has long been a focus of autism research. But its exact role in the condition has been unclear.

Autistic children who have behavioral problems tend to have an enlarged right amygdala, and in girls the size is associated with the severity of certain behaviors.

People with mutations in a gene called TBR1 have unusual features in several brain regions, along with autism traits and developmental delay.

Some cases of anxiety, which often accompanies autism, may stem from a faulty immune system, a new study suggests — but some experts are skeptical.

A new analysis of nearly 40,000 people pinpoints 48 genetic variants that may determine the volume of certain brain areas.

A tiny chunk of the brain’s emotion enter, the amygdala, is enlarged in some autistic children; the larger this piece, the more anxious and depressed the child is likely to be.