title: New insights in the homotopic and heterotopic connectivity of the frontal portion of the human corpus callosum revealed by microdissection and diffusion tractography.
abstract: 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.
authors: Department of Neuroscience and Neurorehabilitation, Neurosurgery Unit, Bambino Gesù Children's Hospital - IRCCS, 4 Piazza Sant'Onofrio, Roma, 00165, Italy.
authors: Alessandro
authors: A
authors: De Benedictis
authors: Groupe D'Imagerie Neurofonctionnelle, Institut Des Maladies Neurodégénératives - UMR 5293, CNRS, CEA University of Bordeaux, Bordeaux, France.
authors: Laurent
authors: L
authors: Petit
authors: Sherbrooke Connectivity Imaging Lab, University of Sherbrooke, Sherbrooke, Québec, Canada.
authors: Maxime
authors: M
authors: Descoteaux
authors: Department of Neuroscience and Neurorehabilitation, Neurosurgery Unit, Bambino Gesù Children's Hospital - IRCCS, 4 Piazza Sant'Onofrio, Roma, 00165, Italy.
authors: Carlo Efisio
authors: CE
authors: Marras
authors: Department of Histopathology, "S. Chiara" Hospital, Trento APSS - 9 Largo Medaglie D'Oro, Trento, 38122, Italy.
authors: Mattia
authors: M
authors: Barbareschi
authors: Department of Neurosciences, Division of Neurosurgery, "S. Chiara" Hospital, Trento APSS - 9 Largo Medaglie D'Oro, Trento, 38122, Italy.|Structural and Functional Connectivity Lab, Division of Neurosurgery, "S. Chiara" Hospital, Trento APSS - 9 Largo Medaglie D'Oro, Trento, 38122, Italy.
authors: Francesco
authors: F
authors: Corsini
authors: Department of Neurosciences, Division of Neurosurgery, "S. Chiara" Hospital, Trento APSS - 9 Largo Medaglie D'Oro, Trento, 38122, Italy.|Structural and Functional Connectivity Lab, Division of Neurosurgery, "S. Chiara" Hospital, Trento APSS - 9 Largo Medaglie D'Oro, Trento, 38122, Italy.
authors: Monica
authors: M
authors: Dallabona
authors: Department of Neurosciences, Division of Neurosurgery, "S. Chiara" Hospital, Trento APSS - 9 Largo Medaglie D'Oro, Trento, 38122, Italy.|Structural and Functional Connectivity Lab, Division of Neurosurgery, "S. Chiara" Hospital, Trento APSS - 9 Largo Medaglie D'Oro, Trento, 38122, Italy.
authors: Franco
authors: F
authors: Chioffi
authors: Department of Neurosciences, Division of Neurosurgery, "S. Chiara" Hospital, Trento APSS - 9 Largo Medaglie D'Oro, Trento, 38122, Italy.|Structural and Functional Connectivity Lab, Division of Neurosurgery, "S. Chiara" Hospital, Trento APSS - 9 Largo Medaglie D'Oro, Trento, 38122, Italy.
authors: Silvio
authors: S
authors: Sarubbo
mesh_terms: D000328:Adult; D002540:Cerebral Cortex / Q000033:anatomy & histology / Q000000981:diagnostic imaging; D003337:Corpus Callosum / Q000033:anatomy & histology* / Q000000981:diagnostic imaging*; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging; D008297:Male; D042282:Microdissection; D008875:Middle Aged; D009434:Neural Pathways / Q000033:anatomy & histology / Q000000981:diagnostic imaging; D055815:Young Adult
keywords: blunt dissection; corpus callosum; human white matter; inter-hemispheric connectivity; tractography