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Published October 19, 2011 | Published
Journal Article Open

Intact Bilateral Resting-State Networks in the Absence of the Corpus Callosum


Temporal correlations between different brain regions in the resting-state BOLD signal are thought to reflect intrinsic functional brain connectivity (Biswal et al., 1995; Greicius et al., 2003; Fox et al., 2007). The functional networks identified are typically bilaterally distributed across the cerebral hemispheres, show similarity to known white matter connections (Greicius et al., 2009), and are seen even in anesthetized monkeys (Vincent et al., 2007). Yet it remains unclear how they arise. Here we tested two distinct possibilities: (1) functional networks arise largely from structural connectivity constraints, and generally require direct interactions between functionally coupled regions mediated by white-matter tracts; and (2) functional networks emerge flexibly with the development of normal cognition and behavior and can be realized in multiple structural architectures. We conducted resting-state fMRI in eight adult humans with complete agenesis of the corpus callosum (AgCC) and normal intelligence, and compared their data to those from eight healthy matched controls. We performed three main analyses: anatomical region-of-interest-based correlations to test homotopic functional connectivity, independent component analysis (ICA) to reveal functional networks with a data-driven approach, and ICA-based interhemispheric correlation analysis. Both groups showed equivalently strong homotopic BOLD correlation. Surprisingly, almost all of the group-level independent components identified in controls were observed in AgCC and were predominantly bilaterally symmetric. The results argue that a normal complement of resting-state networks and intact functional coupling between the hemispheres can emerge in the absence of the corpus callosum, favoring the second over the first possibility listed above.

Additional Information

© 2011 The Authors. Received March 22, 2011; revised Aug. 1, 2011; accepted Aug. 18, 2011. This work was supported by the Simons Foundation (SFARI-07-01 to R.A.), the National Institute of Mental Health (R01 MH080721 to R.A.), and the National Alliance for Research on Schizophrenia and Depression (2009 Young Investigator Award to L.K.P.). We thank Pratik Mukherjee, Elliott Sherr, and Leo Li for helpful discussions regarding this work. We also thank the participants for their invaluable contribution to this research. Author contributions: J.M.T., D.P.K., R.A., and L.K.P. designed research; J.M.T. performed research; J.M.T. analyzed data; J.M.T., D.P.K., R.A., and L.K.P. wrote the paper.

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Published - Tyszka2011p16231J_Neurosci.pdf


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August 19, 2023
October 24, 2023