Functional Assays of Local Connectivity in the Somatosensory Cortex of Individuals with Autism
Article first published online: 20 FEB 2013
© 2013 International Society for Autism Research, Wiley Periodicals, Inc.
Volume 6, Issue 3, pages 190–200, June 2013
How to Cite
Coskun, M. A., Loveland, K. A., Pearson, D. A., Papanicolaou, A. C. and Sheth, B. R. (2013), Functional Assays of Local Connectivity in the Somatosensory Cortex of Individuals with Autism. Autism Res, 6: 190–200. doi: 10.1002/aur.1276
- Issue published online: 14 JUN 2013
- Article first published online: 20 FEB 2013
- Manuscript Accepted: 13 DEC 2012
- Manuscript Received: 29 DEC 2011
- National Alliance for Autism Research—Autism Speaks (BRS)
- National Institutes of Health. Grant Numbers: P01 HD035471, R01 MH072263
- cortical inhibition;
- local excitation;
Emerging evidence for differences between individuals with autism spectrum disorder (ASD) and neurotypical (NT) individuals in somatic processing and brain response to touch suggests somatosensory cortex as a promising substrate for elucidating differences in functional brain connectivity between individuals with and without autism. Signals from adjacent digits project to neighboring locations or representations in somatosensory cortex. When a digit is stimulated, i.e. touched, its representation in cortex is directly activated; local intracortical connections indirectly activate nonprimary cortical representations corresponding to adjacent digits. The response of the nonprimary cortical representations is thus a proxy for connection strength. Local overconnectivity in autism implies that the nonprimary/primary response ratios of the ASD group will be higher than those of the NT group. D1 and D2 of the dominant hand of the participant were individually stimulated while we recorded neural responses using magnetoencephalography. The cortical representations of D1 and D2 (somatosensory-evoked fields) were computed from the ensemble-averaged data using (a) dipole model fits and (b) singular value decomposition. Individual adjacent/primary response ratios were measured, and group response ratio data were fitted with straight lines. Local overconnectivity in autism implies steeper ASD vs. NT group slopes. Our findings did not support local overconnectivity. Slopes were found to be significantly shallower for the ASD group than the NT group. Our findings support the idea of local underconnectivity in the somatosensory cortex of the brains of individuals with ASD. Autism Res 2013, 6: 190–200. © 2013 International Society for Autism Research, Wiley Periodicals, Inc.