Stable long-range interhemispheric coordination is supported by direct anatomical projections.
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.
Rotman Research Institute, Toronto, ON, M6A 2E1, Canada; kshen@research.baycrest.org.
Kelly
K
Shen
Department of Psychological and Brain Sciences, Indiana University, Bloomington, IN 47405;
Bratislav
B
Mišić
Department of Computer Science and Engineering, University of California, San Diego, La Jolla, CA 92093;
Ben N
BN
Cipollini
Rotman Research Institute, Toronto, ON, M6A 2E1, Canada;
Gleb
G
Bezgin
MIND Research Institute, Irvine, CA 92617;
Martin
M
Buschkuehl
Center for Brain Science, Harvard University, Cambridge, MA 02138;
R Matthew
RM
Hutchison
School of Education and Department of Cognitive Science, University of California, Irvine, CA 92697;
Susanne M
SM
Jaeggi
Department of Psychology and.
Ethan
E
Kross
Functional MRI Laboratory, University of Michigan, Ann Arbor, MI 48109;
Scott J
SJ
Peltier
Department of Physiology and Pharmacology and Robarts Research Institute, University of Western Ontario, London, ON, N6A 5K8, Canada;
Stefan
S
Everling
Department of Psychology and.
John
J
Jonides
Rotman Research Institute, Toronto, ON, M6A 2E1, Canada; Department of Psychology, University of Toronto, Toronto, ON, M5S 3G3, Canada; and.
Anthony R
AR
McIntosh
Department of Psychology and Grossman Institute for Neuroscience, Quantitative Biology and Human Behavior, University of Chicago, Chicago IL 60637.
Marc G
MG
Berman
D000818:Animals; D001931:Brain Mapping; D003337:Corpus Callosum / Q000033:anatomy & histology* / Q000502:physiology*; D005260:Female; D007839:Functional Laterality / Q000502:physiology; D006801:Humans; D008251:Macaca; D008279:Magnetic Resonance Imaging; D008297:Male; D009413:Nerve Fibers, Myelinated / Q000502:physiology*; D013045:Species Specificity; D009435:Synaptic Transmission / Q000502:physiology*
dynamics; functional connectivity; homotopy; structural connectivity