Stable long-range interhemispheric coordination is supported by direct anatomical projections

Authors

Kelly Shen, Rotman Research Institute, Toronto, ON, M6A 2E1, Canada; kshen@research.baycrest.org.
Bratislav Mišić, Department of Psychological and Brain Sciences, Indiana University, Bloomington, IN 47405;
Ben N. Cipollini, Department of Computer Science and Engineering, University of California, San Diego, La Jolla, CA 92093;
Gleb Bezgin, Rotman Research Institute, Toronto, ON, M6A 2E1, Canada;
Martin Buschkuehl, MIND Research Institute, Irvine, CA 92617;
R Matthew Hutchison, Center for Brain Science, Harvard University, Cambridge, MA 02138;
Susanne M. Jaeggi, School of Education and Department of Cognitive Science, University of California, Irvine, CA 92697;
Ethan Kross, Department of Psychology and.
Scott J. Peltier, Functional MRI Laboratory, University of Michigan, Ann Arbor, MI 48109;
Stefan Everling, Department of Physiology and Pharmacology and Robarts Research Institute, University of Western Ontario, London, ON, N6A 5K8, Canada;
John Jonides, Department of Psychology and.
Anthony R. McIntosh, Rotman Research Institute, Toronto, ON, M6A 2E1, Canada; Department of Psychology, University of Toronto, Toronto, ON, M5S 3G3, Canada; and.
Marc G. Berman, Department of Psychology and Grossman Institute for Neuroscience, Quantitative Biology and Human Behavior, University of Chicago, Chicago IL 60637.

Document Type

Article

Publication Date

5-19-2015

Journal

Proceedings of the National Academy of Sciences of the United States of America

Volume

112

Issue

20

First Page

6473

Last Page

8

URL with Digital Object Identifier

10.1073/pnas.1503436112

Abstract

The functional interaction between the brain's two hemispheres includes a unique set of connections between corresponding regions in opposite hemispheres (i.e., homotopic regions) that are consistently reported to be exceptionally strong compared with other interhemispheric (i.e., heterotopic) connections. The strength of homotopic functional connectivity (FC) is thought to be mediated by the regions' shared functional roles and their structural connectivity. Recently, homotopic FC was reported to be stable over time despite the presence of dynamic FC across both intrahemispheric and heterotopic connections. Here we build on this work by considering whether homotopic FC is also stable across conditions. We additionally test the hypothesis that strong and stable homotopic FC is supported by the underlying structural connectivity. Consistent with previous findings, interhemispheric FC between homotopic regions were significantly stronger in both humans and macaques. Across conditions, homotopic FC was most resistant to change and therefore was more stable than heterotopic or intrahemispheric connections. Across time, homotopic FC had significantly greater temporal stability than other types of connections. Temporal stability of homotopic FC was facilitated by direct anatomical projections. Importantly, temporal stability varied with the change in conductive properties of callosal axons along the anterior-posterior axis. Taken together, these findings suggest a notable role for the corpus callosum in maintaining stable functional communication between hemispheres.