Posted by Autism Speaks Chief Science Officer Geri Dawson, Ph.D.
I want to share my perspective on an important new research finding released today. The study is headed up by Joe Piven, at the University of North Carolina, Chapel Hill. I am a co-author. The study followed the early brain development of 92 infant siblings, 28 of whom went on to develop autism spectrum disorder (ASD). Infants were imaged using MRI at 6, 12 and 24 months. Those who later developed ASD showed abnormal development of white matter fiber tracts by 6 months. White matter is the part of the brain cell, or neuron, that connects one part of the brain to another. (See our related news item here.)
This finding tells us that, very early and before the emergence of behavioral symptoms, the neural networks that connect different brain regions are not developing normally in infant siblings who go on to develop autism. Previous studies of both children and adults have repeatedly shown that autism involves abnormal connectivity between different brain regions. In fact, my colleagues at the University of Washington and I did one of the first studies to show this. Now we are seeing that these changes are evident by 6 months of age. Future research is needed to help us understand what is causing these early brain changes.
Why is this finding important? First, it helps us understand why people with autism have trouble with complex behaviors such as social interactions. Even simple social behaviors involve coordination of many brain systems. For instance, when something catches a baby’s interest, the normal response is a combination of gestures, babbling and eye contact. This requires several brain regions to communicate efficiently with one another. Even more important, these results offer promise of using imaging results or other “biomarkers” to flag risk of ASD before symptoms become evident. In other conditions such as Alzheimer’s disease and Parkinson’s disease, such early biomarkers are being used to identify those at risk and allow treatment to start before symptoms appear - to maximize benefits.
We can imagine the day when noninvasive brain imaging is available for babies at high risk for autism (such as infant siblings of affected children). When the imaging reveals tell-tale abnormalities, these babies can receive medical or behavioral treatments that stimulate normal brain development. For example, a recent study by Marcel Just demonstrates that certain reading interventions for children with reading disabilities produce positive changes in the children’s brain white matter, or neural connectivity. So, it’s reasonable to consider that some of the changes we are seeing in 6-month-old infants might likewise be improved through early intervention.
Just’s study suggests that such "rewiring" may possible even later in life with interventions that support the connectivity between different brain regions. Parents who are concerned that their baby might be at risk for autism may be wondering whether they should ask their doctor to order an MRI. The results published today are too preliminary for that. We are not recommending MRI screening for autism at this point. The best way to screen for autism at this time is to look for early behavioral signs (see Learn the Signs) and use screening tools such as the M-CHAT. The research published today was funded in part by Autism Speaks and would not be possible without our community’s passionate and continuing support.