A quarterly publication of the Autism Research Institute

The Autism Research Review International is quarterly publication of the Autism Research Institute

Fall, 2016 | Number 4, Volume 30

Reduced asymmetry in ASD may lead to weak central coherence

The hemispheres of the brain may be less specialized in individuals with autism spectrum disorders (ASD) than in neurotypical individuals, a new study indicates. 

Ruth Carper and colleagues used a magnetic resonance imaging (MRI) technique known as diffusion tensor imaging to study the brains of 41 participants with ASD and 44 controls, examining how densely connections formed within different regions of white matter. While other studies have examined language-related asymmetries, the researchers note that their study investigated microstructural asymmetries across a large number of fiber tracts. 

The researchers report that in controls, the right brain hemisphere had more densely packed connections than the left hemisphere. “This fits with the idea that the right hemisphere has a more integrative function, bringing together many kinds of information,” study coauthor Ralph-Axel Müller says. In contrast, the brain connections in individuals with ASD were more evenly distributed across both hemispheres. 

“The idea behind asymmetry in the brain is that there is a division of labor between the two hemispheres,” Müller adds. “It appears this division of labor is reduced in people with autism spectrum disorder.” 

Müller says this reduced asymmetry could result in “weak central coherence,” which he compares to “not seeing the forest for the trees.” He notes that this is consistent with the fact that individuals with ASD are often good at detecting details, while having difficulty consolidating information into a coherent whole. 


Citations

“Reduced hemispheric asymmetry of white matter microstructure in autism spectrum disorder,” Ruth A. Carper, Jeffrey M. Treiber, Shannon Yandall DeJesus, and Ralph-Axel Müller, Child & Adolescent Psychiatry, Vol. 55, No. 12, December 2016, pp. 1073-80. Address: Ruth Carper, Brain Development Imaging Laboratory, Department of Psychology, San Diego State University, 6363 Alvarado Ct., Suite 200, San Diego, CA 92120, [email protected] 

—and— 

“Division of labor in the brain,” Michael Price, SDSU News Center, November 30, 2016.