Functional connectivity in the brain refers to the synchronization of neuronal circuits to transfer information within and between the circuits. Long-range cortical functional connectivity, which links distant areas in the cortex, is often weaker in people with autism spectrum disorders than in controls. It is generally thought, however, that local functional connectivity is stronger in people with the disorder than in controls.
Tal Kenet and her colleagues at Massachusetts General Hospital are using magnetoencephalography (MEG), a technique that reveals cortical activity with high spatial and temporal resolution, to measure both local and long-range functional connectivity. Contrary to the prevailing hypothesis, they have found that local functional connectivity is weaker, not stronger, in people with autism. What’s more, they have found an inverse correlation between the magnitude of local functional connectivity and autism severity: the weaker the local connectivity, the more severe the autism. Their results suggest that the inadequate synchronization of neuronal circuits both within and across cortical regions is characteristic of autism spectrum disorders.
Kenet’s team aims to extend this work by studying local functional connectivity in multiple cortical areas. They plan to carry out MEG experiments in which school-aged participants (7-13 years old) perform both visual and auditory tasks. In their prior work, the researchers found that the magnitude of local functional connectivity was directly proportional to that of long-range functional connectivity. They plan to examine whether this relationship remains true in both visual and auditory areas of the cortex. Lastly, they intend to identify a set of measures of local and long-range functional connectivity that correlate with autism diagnosis, for the possible development of early biomarkers.