Direct Interhemispheric Cortical Communication via Thalamic Commissures: A New White-Matter Pathway in the Rodent Brain
Abstract
The corpus callosum (CC), the anterior (AC), and the posterior (PC) commissures are the principal axonal fiber bundle pathways that allow bidirectional communication between the brain hemispheres. Here, we used the Allen mouse brain connectivity atlas and high-resolution diffusion-weighted MRI (DWI) to investigate interhemispheric fiber bundles in C57bl6/J mice, the most commonly used wild-type mouse model in biomedical research. We identified 1) commissural projections from the primary motor area through the AC to the contralateral hemisphere; and 2) intrathalamic interhemispheric fiber bundles from multiple regions in the frontal cortex to the contralateral thalamus. This is the first description of direct interhemispheric corticothalamic connectivity from the orbital cortex. We named these newly identified crossing points thalamic commissures. We also analyzed interhemispheric connectivity in the Balb/c mouse model of dysgenesis of the corpus callosum (CCD). Relative to C57bl6/J, Balb/c presented an atypical and smaller AC and weaker interhemispheric corticothalamic communication. These results redefine our understanding of interhemispheric brain communication. Specifically, they establish the thalamus as a regular hub for interhemispheric connectivity and encourage us to reinterpret brain plasticity in CCD as an altered balance between axonal reinforcement and pruning.
Additional Information
© Published by Oxford University Press 2021. This work is written by US Government employees and is in the public domain in the US. Received: 26 January 2021; Revision received: 16 March 2021; Accepted: 07 April 2021; Published: 17 May 2021. We would like to thank Lisa Zhang for technical support. We also thank the members and affiliates of the International Research Consortium for the Corpus Callosum and Cerebral Connectivity (IRC5, https://www.irc5.org) for discussions and input. Conflict of Interest: None declared. This work was supported by the PA Department of Health SAP grant 4100083102 to A.C.S.; the Research Support Foundation of the State of Rio de Janeiro (FAPERJ); the National Council for Scientific and Technological Development (CNPq); as well as by intramural grants from D'Or Institute for Research and Education (IDOR). This research was also supported (in part) by the Intramural Research Program of the National Institutes of Health, National Insitute of Neurological Disorders and Stroke (grant ZIANS003041 to A.C.S.).Attached Files
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Supplemental Material - supp1_bhab112.jpeg
Supplemental Material - supp2_bhab112.jpeg
Supplemental Material - szczupak_supp_legends_bhab112.pdf
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Additional details
- PMCID
- PMC8408456
- Eprint ID
- 112009
- Resolver ID
- CaltechAUTHORS:20211123-182349897
- 4100083102
- Pennsylvania Department of Health
- Fundação de Amparo à Pesquisa do Estado do Rio de Janeiro (FAPERJ)
- Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
- D'Or Institute for Research and Education (IDOR)
- ZIANS003041
- NIH
- Created
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2021-11-23Created from EPrint's datestamp field
- Updated
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2023-07-07Created from EPrint's last_modified field