A common theme in contemporary research about autism spectrum disorder (ASD) is connectivity. A number of recent studies have investigated how the connections between brain regions could be an underlying cause of ASD, but there is more to brain activity than connectivity. A new study from University College London and the National Institute of Mental Health in Bethesda, Maryland looked at how brain synchronicity is involved in ASD. The results demonstrate that people with ASD have overly synchronized brain activity. This could explain why people with ASD are easily overwhelmed by social situations.
The researchers conducted functional magnetic resonance imaging (fMRI) scans of 19 men and boys with ASD and of 20 age-matched controls. The participants engaged in video chats while in the fMRI scanner. They held three six-minute conversations about their work, school, and hobbies. They also took turns reciting nursery rhymes for the same amount of time. The researchers analyzed which brain regions were synchronized—simultaneously active—during the conversation phases. They also compared brain activity from the conversations to activity during the nursery rhyme recitations.
The participants with ASD had more pairs of synchronized brain regions than the controls. The researchers identified 19 pairs of regions that were more active in the ASD participants. Many of the regions are involved in processing movement or sensory information. For example, one of the synchronized pairs included the postcentral gyrus (a sensory and motor region) and the right precuneus (a memory and self-reflection region). All the pairs the researchers observed were over-synchronized in the participants with ASD. The controls all exhibited less synchronicity than the participants with ASD.
When the researchers compared brain activity from the conversations to the activity during the nursery rhyme recitations, they found 14 pairs of over-synchronized regions in the participants with ASD. Many of these regions are related to social functions.
The findings suggest that people with ASD struggle to focus their brain activity. Conversation and social activities may be difficult for people with ASD because their brains are much more active than necessary.
This research was presented at the 2015 Society for Neuroscience annual meeting.
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