Brain plasticity following corpus callosum agenesis or loss: a review of the Probst bundles
The corpus callosum is the largest axonal tract in the human brain, connecting the left and right cortical hemipheres. This structure is affected in myriad human neurodevelopmental disorders, and can be entirely absent as a result of congenital or surgical causes. The age when callosal loss occurs,...
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| Format: | Article |
| Language: | English |
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Frontiers Media S.A.
2023-11-01
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| Series: | Frontiers in Neuroanatomy |
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| Online Access: | https://www.frontiersin.org/articles/10.3389/fnana.2023.1296779/full |
| _version_ | 1797635760948510720 |
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| author | Zorana Lynton Zorana Lynton Rodrigo Suárez Rodrigo Suárez Laura R. Fenlon Laura R. Fenlon |
| author_facet | Zorana Lynton Zorana Lynton Rodrigo Suárez Rodrigo Suárez Laura R. Fenlon Laura R. Fenlon |
| author_sort | Zorana Lynton |
| collection | DOAJ |
| description | The corpus callosum is the largest axonal tract in the human brain, connecting the left and right cortical hemipheres. This structure is affected in myriad human neurodevelopmental disorders, and can be entirely absent as a result of congenital or surgical causes. The age when callosal loss occurs, for example via surgical section in cases of refractory epilepsy, correlates with resulting brain morphology and neuropsychological outcomes, whereby an earlier loss generally produces relatively improved interhemispheric connectivity compared to a loss in adulthood (known as the “Sperry’s paradox”). However, the mechanisms behind these age-dependent differences remain unclear. Perhaps the best documented and most striking of the plastic changes that occur due to developmental, but not adult, callosal loss is the formation of large, bilateral, longitudinal ectopic tracts termed Probst bundles. Despite over 100 years of research into these ectopic tracts, which are the largest and best described stereotypical ectopic brain tracts in humans, much remains unclear about them. Here, we review the anatomy of the Probst bundles, along with evidence for their faciliatory or detrimental function, the required conditions for their formation, patterns of etiology, and mechanisms of development. We provide hypotheses for many of the remaining mysteries of the Probst bundles, including their possible relationship to preserved interhemispheric communication following corpus callosum absence. Future research into naturally occurring plastic tracts such as Probst bundles will help to inform the general rules governing axon plasticity and disorders of brain miswiring. |
| first_indexed | 2024-03-11T12:25:55Z |
| format | Article |
| id | doaj.art-a4dcaf0a7e5b48c48159b17962027d42 |
| institution | Directory Open Access Journal |
| issn | 1662-5129 |
| language | English |
| last_indexed | 2024-03-11T12:25:55Z |
| publishDate | 2023-11-01 |
| publisher | Frontiers Media S.A. |
| record_format | Article |
| series | Frontiers in Neuroanatomy |
| spelling | doaj.art-a4dcaf0a7e5b48c48159b17962027d422023-11-06T09:57:03ZengFrontiers Media S.A.Frontiers in Neuroanatomy1662-51292023-11-011710.3389/fnana.2023.12967791296779Brain plasticity following corpus callosum agenesis or loss: a review of the Probst bundlesZorana Lynton0Zorana Lynton1Rodrigo Suárez2Rodrigo Suárez3Laura R. Fenlon4Laura R. Fenlon5School of Biomedical Sciences, Faculty of Medicine, The University of Queensland, St Lucia, QLD, AustraliaQueensland Brain Institute, The University of Queensland, St Lucia, QLD, AustraliaSchool of Biomedical Sciences, Faculty of Medicine, The University of Queensland, St Lucia, QLD, AustraliaQueensland Brain Institute, The University of Queensland, St Lucia, QLD, AustraliaSchool of Biomedical Sciences, Faculty of Medicine, The University of Queensland, St Lucia, QLD, AustraliaQueensland Brain Institute, The University of Queensland, St Lucia, QLD, AustraliaThe corpus callosum is the largest axonal tract in the human brain, connecting the left and right cortical hemipheres. This structure is affected in myriad human neurodevelopmental disorders, and can be entirely absent as a result of congenital or surgical causes. The age when callosal loss occurs, for example via surgical section in cases of refractory epilepsy, correlates with resulting brain morphology and neuropsychological outcomes, whereby an earlier loss generally produces relatively improved interhemispheric connectivity compared to a loss in adulthood (known as the “Sperry’s paradox”). However, the mechanisms behind these age-dependent differences remain unclear. Perhaps the best documented and most striking of the plastic changes that occur due to developmental, but not adult, callosal loss is the formation of large, bilateral, longitudinal ectopic tracts termed Probst bundles. Despite over 100 years of research into these ectopic tracts, which are the largest and best described stereotypical ectopic brain tracts in humans, much remains unclear about them. Here, we review the anatomy of the Probst bundles, along with evidence for their faciliatory or detrimental function, the required conditions for their formation, patterns of etiology, and mechanisms of development. We provide hypotheses for many of the remaining mysteries of the Probst bundles, including their possible relationship to preserved interhemispheric communication following corpus callosum absence. Future research into naturally occurring plastic tracts such as Probst bundles will help to inform the general rules governing axon plasticity and disorders of brain miswiring.https://www.frontiersin.org/articles/10.3389/fnana.2023.1296779/fullinterhemispheric communicationbrain developmentcallosotomycommissurotomysplit brainneurodevelopmental plasticity |
| spellingShingle | Zorana Lynton Zorana Lynton Rodrigo Suárez Rodrigo Suárez Laura R. Fenlon Laura R. Fenlon Brain plasticity following corpus callosum agenesis or loss: a review of the Probst bundles Frontiers in Neuroanatomy interhemispheric communication brain development callosotomy commissurotomy split brain neurodevelopmental plasticity |
| title | Brain plasticity following corpus callosum agenesis or loss: a review of the Probst bundles |
| title_full | Brain plasticity following corpus callosum agenesis or loss: a review of the Probst bundles |
| title_fullStr | Brain plasticity following corpus callosum agenesis or loss: a review of the Probst bundles |
| title_full_unstemmed | Brain plasticity following corpus callosum agenesis or loss: a review of the Probst bundles |
| title_short | Brain plasticity following corpus callosum agenesis or loss: a review of the Probst bundles |
| title_sort | brain plasticity following corpus callosum agenesis or loss a review of the probst bundles |
| topic | interhemispheric communication brain development callosotomy commissurotomy split brain neurodevelopmental plasticity |
| url | https://www.frontiersin.org/articles/10.3389/fnana.2023.1296779/full |
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