Full interhemispheric integration sustained by a fraction of posterior callosal fibers

The dynamic integration of the lateralized and specialized capacities of the two cerebral hemispheres constitutes a hallmark feature of human brain function. This interhemispheric exchange of information critically depends upon the corpus callosum. Classical anatomical descriptions of callosal organization outline a topographic gradient from front to back, such that specific transcallosal fibers support distinct aspects of integrated brain function. Here, we present a challenge to this conventional model. Using neuroimaging data obtained from a new cohort of adult corpus callosotomy patients, we leverage modern network neuroscience techniques to show that full interhemispheric integration can be achieved via a small proportion of posterior callosal fibers. Partial callosotomy patients with spared callosal fibers retained widespread patterns of interhemispheric functional connectivity and showed no signs of behavioral disconnection, even with only 1 cm of the splenium intact. Conversely, only complete callosotomy patients demonstrated sweeping disruptions of interhemispheric network architectures, aligning with disconnection syndromes long-thought to reflect diminished information propagation and communication across the brain. These findings motivate an evolving mechanistic understanding of synchronized interhemispheric neural activity for large-scale human brain function and behavior.

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Publication Details

Journal
Proceedings of the National Academy of Sciences
Published
2025-10-21
DOI
https://doi.org/10.1073/pnas.2520190122
Citations
1
Primary Topic
Functional Brain Connectivity Studies
Type
article
Field-Weighted Citation Impact
1.43
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article

Full interhemispheric integration sustained by a fraction of posterior callosal fibers

Olaf Sporns, Tyler Santander, Michael B. Miller, Valerie M. Wiemer et al.
1 citations
Proceedings of the National Academy of Sciences
Functional Brain Connectivity Studies
1.43
article

Full interhemispheric integration sustained by a fraction of posterior callosal fibers

Olaf Sporns, Tyler Santander, Michael B. Miller, Valerie M. Wiemer, Anna Rada, Friedrich G. Woermann, Thilo Kalbhenn, Theresa Paul, Barry Giesbrecht, Lukas J. Volz, Christian G. Bien, Johanna L. Hopf, Jessica M. Simonson, Michael S. Gazzaniga, Henri Etel Skinner, Selin Bekir
article en
1 citations

Abstract

The dynamic integration of the lateralized and specialized capacities of the two cerebral hemispheres constitutes a hallmark feature of human brain function. This interhemispheric exchange of information critically depends upon the corpus callosum. Classical anatomical descriptions of callosal organization outline a topographic gradient from front to back, such that specific transcallosal fibers support distinct aspects of integrated brain function. Here, we present a challenge to this conventional model. Using neuroimaging data obtained from a new cohort of adult corpus callosotomy patients, we leverage modern network neuroscience techniques to show that full interhemispheric integration can be achieved via a small proportion of posterior callosal fibers. Partial callosotomy patients with spared callosal fibers retained widespread patterns of interhemispheric functional connectivity and showed no signs of behavioral disconnection, even with only 1 cm of the splenium intact. Conversely, only complete callosotomy patients demonstrated sweeping disruptions of interhemispheric network architectures, aligning with disconnection syndromes long-thought to reflect diminished information propagation and communication across the brain. These findings motivate an evolving mechanistic understanding of synchronized interhemispheric neural activity for large-scale human brain function and behavior.

Proceedings of the National Academy of SciencesVol. 122(43)
University of California, Santa Barbara (US), University of Cologne (DE), Bielefeld University (DE), University of California System (US), Faculty (United Kingdom) (GB), Evangelisches Krankenhaus Bielefeld (DE), Indiana University Bloomington (US), Evangelisches Klinikum Köln Weyertal (DE), University Hospital Cologne (DE), Institute for Collaborative Biotechnologies, Epilepsy Society (GB), Indiana University (US), Bethel University (US)
Openalex Percentile: Top 15%
Functional Brain Connectivity Studies
1.43
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