Reframing neural decussation: A vision-based theory for contralateral control

<p>Neural decussation, the systematic crossing of sensory and motor pathways at the midline, is one of the most prominent features of the vertebrate nervous system, yet its functional rationale has remained unresolved. This work proposes the Visual-Origin Theory of Neuronal Decussation, which...

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Main Author: Ghassan Ahmed Mubasher Mohamedsalih (22963423) (author)
Published: 2025
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author Ghassan Ahmed Mubasher Mohamedsalih (22963423)
author_facet Ghassan Ahmed Mubasher Mohamedsalih (22963423)
author_role author
dc.creator.none.fl_str_mv Ghassan Ahmed Mubasher Mohamedsalih (22963423)
dc.date.none.fl_str_mv 2025-12-22T21:00:00Z
dc.identifier.none.fl_str_mv 10.1016/j.biosystems.2025.105683
dc.relation.none.fl_str_mv https://figshare.com/articles/journal_contribution/Reframing_neural_decussation_A_vision-based_theory_for_contralateral_control/31017715
dc.rights.none.fl_str_mv CC BY 4.0
info:eu-repo/semantics/openAccess
dc.subject.none.fl_str_mv Biomedical and clinical sciences
Neurosciences
Neural decussation
Optic chiasm
Visual motor integration
Contralateral control
Geometrical optics
dc.title.none.fl_str_mv Reframing neural decussation: A vision-based theory for contralateral control
dc.type.none.fl_str_mv Text
Journal contribution
info:eu-repo/semantics/publishedVersion
text
contribution to journal
description <p>Neural decussation, the systematic crossing of sensory and motor pathways at the midline, is one of the most prominent features of the vertebrate nervous system, yet its functional rationale has remained unresolved. This work proposes the Visual-Origin Theory of Neuronal Decussation, which argues that contralateral organization arises as a direct consequence of visual field optical geometry. Light rays from the right visual hemifield physically cross the midsagittal plane before reaching the temporal retina, and so do rays from the left hemifield in the opposite direction. The decussation of nasal retinal fibers in the optic chiasm does not create this crossing; it preserves a pre-existing physical pattern, thereby aligning each cerebral hemisphere with the contralateral half of external space, the only configuration that places a processing center directly “behind” the region of the world it must monitor and act upon. Once hemispheric ownership of visual space is established, motor pathways must follow the same spatial logic. The sensorimotor decussations are therefore the downstream continuation of the same spatial imperative: the shortest, fastest, and most coherent route from a field-specific sensory representation to the effectors acting in that same field is a single midline crossing in the brainstem. A proof-by-exclusion analysis shows that alternative wiring schemes, including fully ipsilateral or reversed crossing patterns, disrupt binocular vision, slow rapid left–right motor responses, and generate visuomotor instabilities observed in clinical disorders of wiring. Comparative evidence across vertebrates, and contrasts with arthropods support the conclusion that neural decussation is an inevitable consequence of vision.</p><h2>Other Information</h2> <p> Published in: BioSystems<br> License: <a href="http://creativecommons.org/licenses/by/4.0/" target="_blank">http://creativecommons.org/licenses/by/4.0/</a><br>See article on publisher's website: <a href="https://dx.doi.org/10.1016/j.biosystems.2025.105683" target="_blank">https://dx.doi.org/10.1016/j.biosystems.2025.105683</a></p>
eu_rights_str_mv openAccess
id Manara2_23b14f76e795f680e3b186fe50482fe9
identifier_str_mv 10.1016/j.biosystems.2025.105683
network_acronym_str Manara2
network_name_str Manara2
oai_identifier_str oai:figshare.com:article/31017715
publishDate 2025
repository.mail.fl_str_mv
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rights_invalid_str_mv CC BY 4.0
spelling Reframing neural decussation: A vision-based theory for contralateral controlGhassan Ahmed Mubasher Mohamedsalih (22963423)Biomedical and clinical sciencesNeurosciencesNeural decussationOptic chiasmVisual motor integrationContralateral controlGeometrical optics<p>Neural decussation, the systematic crossing of sensory and motor pathways at the midline, is one of the most prominent features of the vertebrate nervous system, yet its functional rationale has remained unresolved. This work proposes the Visual-Origin Theory of Neuronal Decussation, which argues that contralateral organization arises as a direct consequence of visual field optical geometry. Light rays from the right visual hemifield physically cross the midsagittal plane before reaching the temporal retina, and so do rays from the left hemifield in the opposite direction. The decussation of nasal retinal fibers in the optic chiasm does not create this crossing; it preserves a pre-existing physical pattern, thereby aligning each cerebral hemisphere with the contralateral half of external space, the only configuration that places a processing center directly “behind” the region of the world it must monitor and act upon. Once hemispheric ownership of visual space is established, motor pathways must follow the same spatial logic. The sensorimotor decussations are therefore the downstream continuation of the same spatial imperative: the shortest, fastest, and most coherent route from a field-specific sensory representation to the effectors acting in that same field is a single midline crossing in the brainstem. A proof-by-exclusion analysis shows that alternative wiring schemes, including fully ipsilateral or reversed crossing patterns, disrupt binocular vision, slow rapid left–right motor responses, and generate visuomotor instabilities observed in clinical disorders of wiring. Comparative evidence across vertebrates, and contrasts with arthropods support the conclusion that neural decussation is an inevitable consequence of vision.</p><h2>Other Information</h2> <p> Published in: BioSystems<br> License: <a href="http://creativecommons.org/licenses/by/4.0/" target="_blank">http://creativecommons.org/licenses/by/4.0/</a><br>See article on publisher's website: <a href="https://dx.doi.org/10.1016/j.biosystems.2025.105683" target="_blank">https://dx.doi.org/10.1016/j.biosystems.2025.105683</a></p>2025-12-22T21:00:00ZTextJournal contributioninfo:eu-repo/semantics/publishedVersiontextcontribution to journal10.1016/j.biosystems.2025.105683https://figshare.com/articles/journal_contribution/Reframing_neural_decussation_A_vision-based_theory_for_contralateral_control/31017715CC BY 4.0info:eu-repo/semantics/openAccessoai:figshare.com:article/310177152025-12-22T21:00:00Z
spellingShingle Reframing neural decussation: A vision-based theory for contralateral control
Ghassan Ahmed Mubasher Mohamedsalih (22963423)
Biomedical and clinical sciences
Neurosciences
Neural decussation
Optic chiasm
Visual motor integration
Contralateral control
Geometrical optics
status_str publishedVersion
title Reframing neural decussation: A vision-based theory for contralateral control
title_full Reframing neural decussation: A vision-based theory for contralateral control
title_fullStr Reframing neural decussation: A vision-based theory for contralateral control
title_full_unstemmed Reframing neural decussation: A vision-based theory for contralateral control
title_short Reframing neural decussation: A vision-based theory for contralateral control
title_sort Reframing neural decussation: A vision-based theory for contralateral control
topic Biomedical and clinical sciences
Neurosciences
Neural decussation
Optic chiasm
Visual motor integration
Contralateral control
Geometrical optics