Decreased Interhemispheric Functional Connectivity in Autism

Department of Neuroradiology, University of Utah, 1A71 School of Medicine, Salt Lake City, UT 84132, USA.
Cerebral Cortex (Impact Factor: 8.67). 10/2010; 21(5):1134-46. DOI: 10.1093/cercor/bhq190
Source: PubMed


The cortical underconnectivity theory asserts that reduced long-range functional connectivity might contribute to a neural mechanism for autism. We examined resting-state blood oxygen level-dependent interhemispheric correlation in 53 males with high-functioning autism and 39 typically developing males from late childhood through early adulthood. By constructing spatial maps of correlation between homologous voxels in each hemisphere, we found significantly reduced interhemispheric correlation specific to regions with functional relevance to autism: sensorimotor cortex, anterior insula, fusiform gyrus, superior temporal gyrus, and superior parietal lobule. Observed interhemispheric connectivity differences were better explained by diagnosis of autism than by potentially confounding neuropsychological metrics of language, IQ, or handedness. Although both corpus callosal volume and gray matter interhemispheric connectivity were significantly reduced in autism, no direct relationship was observed between them, suggesting that structural and functional metrics measure different aspects of interhemispheric connectivity. In the control but not the autism sample, there was decreasing interhemispheric correlation with subject age. Greater differences in interhemispheric correlation were seen for more lateral regions in the brain. These findings suggest that long-range connectivity abnormalities in autism are spatially heterogeneous and that transcallosal connectivity is decreased most in regions with functions associated with behavioral abnormalities in autism. Autism subjects continue to show developmental differences in interhemispheric connectivity into early adulthood.

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Available from: Jason R. Cooperrider, May 20, 2015
    • "Hence, this approach might prove valuable for testing the neural mechanisms of face processing at the individual-subject level. Furthermore, as the interhemispheric integration is an important but often neglected aspect of the pathophysiology of psychiatric disorders [e.g., Anderson et al., 2011], the paradigm might also enable deeper insight into psychiatric disorders in which face perception is impaired [e.g., autism spectrum disorders; Vissers et al., 2012]. "
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    • "VMHC is a voxelwise measurement of functional homotopy that reveals the synchrony of resting-state functional connectivity between a voxel in one hemisphere and its mirrored counterpart in the other. VMHC has been successfully used to explore the interhemispheric functional coordination in autism, schizophrenia, cocaine addiction, and other diseases [24] [25] [26] [27] [28]; however, VMHC has, to our knowledge, not been used previously to investigate interhemispheric functional coordination in tinnitus patients and to study the relationships between altered interhemispheric functional connectivity and other tinnitus characteristics such as tinnitus duration or severity. "
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    • "However, several studies have reported that hemispheric activation, structure, and/or functional connectivity differ between ASD and non-autistic individuals. For instance, reduced inter-hemispheric connectivity, implying less interhemispheric synchronization, has been noted in adults (Anderson et al. 2011) and toddlers (Dinstein et al. 2011) with ASD using resting state fMRI. There have also been several reports of anatomical differences between hemispheres in individuals with ASD versus controls, including larger right parieto-occipital regions (Hier et al. 1979), and smaller left planum temporale (Rojas et al. 2002). "
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