New insights in the homotopic and heterotopic connectivity of the frontal portion of the human corpus callosum revealed by microdissection and diffusion tractography
Hum. Brain Mapp.. 2016-08-08; 37(12): 4718-4735
DOI: 10.1002/hbm.23339
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1. Hum Brain Mapp. 2016 Dec;37(12):4718-4735. doi: 10.1002/hbm.23339. Epub 2016 Aug
8.
New insights in the homotopic and heterotopic connectivity of the frontal portion
of the human corpus callosum revealed by microdissection and diffusion
tractography.
De Benedictis A(1), Petit L(2), Descoteaux M(3), Marras CE(1), Barbareschi M(4),
Corsini F(5)(6), Dallabona M(5)(6), Chioffi F(5)(6), Sarubbo S(5)(6).
Author information:
(1)Department of Neuroscience and Neurorehabilitation, Neurosurgery Unit, Bambino
Gesù Children’s Hospital – IRCCS, 4 Piazza Sant’Onofrio, Roma, 00165, Italy.
(2)Groupe D’Imagerie Neurofonctionnelle, Institut Des Maladies Neurodégénératives
– UMR 5293, CNRS, CEA University of Bordeaux, Bordeaux, France.
(3)Sherbrooke Connectivity Imaging Lab, University of Sherbrooke, Sherbrooke,
Québec, Canada.
(4)Department of Histopathology, “S. Chiara” Hospital, Trento APSS – 9 Largo
Medaglie D’Oro, Trento, 38122, Italy.
(5)Department of Neurosciences, Division of Neurosurgery, “S. Chiara” Hospital,
Trento APSS – 9 Largo Medaglie D’Oro, Trento, 38122, Italy.
(6)Structural and Functional Connectivity Lab, Division of Neurosurgery, “S.
Chiara” Hospital, Trento APSS – 9 Largo Medaglie D’Oro, Trento, 38122, Italy.
Extensive studies revealed that the human corpus callosum (CC) plays a crucial
role in providing large-scale bi-hemispheric integration of sensory, motor and
cognitive processing, especially within the frontal lobe. However, the literature
lacks of conclusive data regarding the structural macroscopic connectivity of the
frontal CC. In this study, a novel microdissection approach was adopted, to
expose the frontal fibers of CC from the dorsum to the lateral cortex in eight
hemispheres and in one entire brain. Post-mortem results were then combined with
data from advanced constrained spherical deconvolution in 130 healthy subjects.
We demonstrated as the frontal CC provides dense inter-hemispheric connections.
In particular, we found three types of fronto-callosal fibers, having a
dorso-ventral organization. First, the dorso-medial CC fibers subserve homotopic
connections between the homologous medial cortices of the superior frontal gyrus.
Second, the ventro-lateral CC fibers subserve homotopic connections between
lateral frontal cortices, including both the middle frontal gyrus and the
inferior frontal gyrus, as well as heterotopic connections between the medial and
lateral frontal cortices. Third, the ventro-striatal CC fibers connect the medial
and lateral frontal cortices with the contralateral putamen and caudate nucleus.
We also highlighted an intricate crossing of CC fibers with the main association
pathways terminating in the lateral regions of the frontal lobes. This combined
approach of ex vivo microdissection and in vivo diffusion tractography allowed
demonstrating a previously unappreciated three-dimensional architecture of the
anterior frontal CC, thus clarifying the functional role of the CC in mediating
the inter-hemispheric connectivity. Hum Brain Mapp 37:4718-4735, 2016. © 2016
Wiley Periodicals, Inc.
© 2016 Wiley Periodicals, Inc.
DOI: 10.1002/hbm.23339
PMID: 27500966 [Indexed for MEDLINE]