Autism Brains Marked by Weak Local Connections

Connections between neighboring groups of brain cells are weaker in individuals with autism than in controls, according to a report published 14 January in the Proceedings of the National Academy of Sciences.This is the latest of several studies in the past year to cast doubt on the so-called ‘connectivity theory’ of autism, which broadly says that people with autism have stronger connections between neighboring brain regions and weaker connections between distant regions than controls do.Using magnetoencephalography (MEG), a noninvasive imaging technique that uses magnetic fields to track rapid changes in brain waves, the new study found that both short- and long-range connections are impaired in autism.What’s more, the weakest local connections are found in those with the most severe autism symptoms, the study found.That both short- and long-range connections are weaker in autism makes intuitive sense, says lead investigator Tal Kenet, an instructor in neurology at Harvard Medical School.“What always bothered me about the [connectivity] hypothesis was, why would neurons be really bad at long-range but good at it locally?” she says.Read more at...SFARI, February 2013.