What is special about the human arcuate fasciculus? Lateralization, projections, and expansion

Evolutionary adaptations of the human brain are the basis for our unique abilities such as language. An expansion of the arcuate fasciculus (AF), the dorsal language tract, in the human lineage involving left lateralization is considered canonical, but this hypothesis has not been tested in relation...

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Main Authors: Eichert, N, Verhagen, L, Folloni, D, Jbabdi, S, Khrapichev, A, Sibson, N, Mantini, D, Sallet, J, Mars, R
Format: Journal article
Published: Elsevier 2018
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author Eichert, N
Verhagen, L
Folloni, D
Jbabdi, S
Khrapichev, A
Sibson, N
Mantini, D
Sallet, J
Mars, R
author_facet Eichert, N
Verhagen, L
Folloni, D
Jbabdi, S
Khrapichev, A
Sibson, N
Mantini, D
Sallet, J
Mars, R
author_sort Eichert, N
collection OXFORD
description Evolutionary adaptations of the human brain are the basis for our unique abilities such as language. An expansion of the arcuate fasciculus (AF), the dorsal language tract, in the human lineage involving left lateralization is considered canonical, but this hypothesis has not been tested in relation to other architectural adaptations in the human brain. Using diffusion-weighted MRI, we examined AF in the human and macaque and quantified species differences in white matter architecture and surface representations. To compare surface results in the two species, we transformed macaque representations to human space using a landmark-based monkey-to-human cortical expansion model. We found that the human dorsal AF, but not the ventral inferior fronto-occipital fasciculus (IFO), is left-lateralized. In the monkey AF is not lateralized. Moreover, compared to the macaque, human AF is relatively increased with respect to IFO. A comparison of human and transformed macaque surface representations suggests that cortical expansion alone cannot account for the species differences in the surface representation of AF. Our results show that the human AF has undergone critical anatomical modifications in comparison with the macaque AF. More generally, this work demonstrates that studies on the human brain specializations underlying the language connectome can benefit from current methodological advances in comparative neuroanatomy.
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spelling oxford-uuid:353d5f1f-e7a7-49fd-98fe-4fa898db0c502022-03-26T13:30:46ZWhat is special about the human arcuate fasciculus? Lateralization, projections, and expansionJournal articlehttp://purl.org/coar/resource_type/c_dcae04bcuuid:353d5f1f-e7a7-49fd-98fe-4fa898db0c50Symplectic Elements at OxfordElsevier2018Eichert, NVerhagen, LFolloni, DJbabdi, SKhrapichev, ASibson, NMantini, DSallet, JMars, REvolutionary adaptations of the human brain are the basis for our unique abilities such as language. An expansion of the arcuate fasciculus (AF), the dorsal language tract, in the human lineage involving left lateralization is considered canonical, but this hypothesis has not been tested in relation to other architectural adaptations in the human brain. Using diffusion-weighted MRI, we examined AF in the human and macaque and quantified species differences in white matter architecture and surface representations. To compare surface results in the two species, we transformed macaque representations to human space using a landmark-based monkey-to-human cortical expansion model. We found that the human dorsal AF, but not the ventral inferior fronto-occipital fasciculus (IFO), is left-lateralized. In the monkey AF is not lateralized. Moreover, compared to the macaque, human AF is relatively increased with respect to IFO. A comparison of human and transformed macaque surface representations suggests that cortical expansion alone cannot account for the species differences in the surface representation of AF. Our results show that the human AF has undergone critical anatomical modifications in comparison with the macaque AF. More generally, this work demonstrates that studies on the human brain specializations underlying the language connectome can benefit from current methodological advances in comparative neuroanatomy.
spellingShingle Eichert, N
Verhagen, L
Folloni, D
Jbabdi, S
Khrapichev, A
Sibson, N
Mantini, D
Sallet, J
Mars, R
What is special about the human arcuate fasciculus? Lateralization, projections, and expansion
title What is special about the human arcuate fasciculus? Lateralization, projections, and expansion
title_full What is special about the human arcuate fasciculus? Lateralization, projections, and expansion
title_fullStr What is special about the human arcuate fasciculus? Lateralization, projections, and expansion
title_full_unstemmed What is special about the human arcuate fasciculus? Lateralization, projections, and expansion
title_short What is special about the human arcuate fasciculus? Lateralization, projections, and expansion
title_sort what is special about the human arcuate fasciculus lateralization projections and expansion
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