Autism or the Lack Thereof

Can you see the figure on the left within the figure on the right? (hint: try looking at the lower left corner of the figure on the right).  In a journal article published last month, Michael Spencer and colleagues from Cambridge explained that while people with autism perform normally on tasks like this one, they demonstrate deficits at the level of brain activation while performing such tasks.

The authors state that people with autism demonstrate a failure to deactivate certain brain regions that make up the default mode network when performing complex tasks like the one pictured. These regions, including the prefrontal cortex and the posterior cinguate cortex, may be collectively responsible for abstract mental activities like day dreaming. Why would deactivating the default mode network be important when performing complex tasks?  In a way, taking certain parts of the brain offline clears the air from distracting thoughts, allowing one to focus on the task at hand.

What’s interesting is that the authors not only found this failure to deactivate in people with autism but also in their siblings who don’t have autism.  In other words, when performing a task similar to the one above, the brain activity of brothers or sisters of people with autism looks more autistic-like than typical.  The authors present this finding as a potential endophenotype, or marker for familial risk, of autism.  Though this finding is only preliminary, it shows that siblings of people with autism (who share some genetic similarities with their siblings) may display certain traits that are indicative of autism, without actually having the disorder.  If this concept holds, it could provide a better picture of what goes on genetically in autism, or in the lack thereof.

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