About 80 percent of adults with autism exhibit restricted or repetitive behaviors, such as hand flapping, teeth grinding, or rocking back and forth. A new fMRI study of 15 autistic people finds that these repetitive behaviors are associated with abnormal activity in the “executive” brain system that’s responsible for attention, planning, and for inhibiting inappropriate behaviors.

Older brain-imaging research on people with autism overwhelmingly focused on social aspects of behavior, such as the processing of faces.

Testing for neural changes during repetitive behaviors is more difficult because of the constraints of an fMRI machine, in which subjects must lie still. “More than three to four millimeters of head motion will invalidate an entire study,” says Hofstra University neuroscientist Keith Shafritz, lead author of the new study.

To jump this hurdle, Shafritz used a novel testing paradigm that forced subjects to activate the cognitive processes behind repetitive behaviors without actually making any motions.

…read the rest of my latest piece at the Simons Foundation website