title: Intrahemispheric cortico-cortical connections of the human auditory cortex.
abstract: The human auditory cortex comprises the supratemporal plane and large parts of the temporal and parietal convexities. We have investigated the relevant intrahemispheric cortico-cortical connections using in vivo DSI tractography combined with landmark-based registration, automatic cortical parcellation and whole-brain structural connection matrices in 20 right-handed male subjects. On the supratemporal plane, the pattern of connectivity was related to the architectonically defined early-stage auditory areas. It revealed a three-tier architecture characterized by a cascade of connections from the primary auditory cortex to six adjacent non-primary areas and from there to the superior temporal gyrus. Graph theory-driven analysis confirmed the cascade-like connectivity pattern and demonstrated a strong degree of segregation and hierarchy within early-stage auditory areas. Putative higher-order areas on the temporal and parietal convexities had more widely spread local connectivity and long-range connections with the prefrontal cortex; analysis of optimal community structure revealed five distinct modules in each hemisphere. The pattern of temporo-parieto-frontal connectivity was partially asymmetrical. In conclusion, the human early-stage auditory cortical connectivity, as revealed by in vivo DSI tractography, has strong similarities with that of non-human primates. The modular architecture and hemispheric asymmetry in higher-order regions is compatible with segregated processing streams and lateralization of cognitive functions.
authors.affiliation: Service de Neuropsychologie et de Neuroréhabilitation, CHUV, Université de Lausanne, Lausanne, Switzerland. Leila.Cammoun@hotmail.ch.
authors.forename: Leila
authors.initials: L
authors.lastname: Cammoun
authors.affiliation: Signal Processing Laboratory, EPFL, Lausanne, Switzerland.
authors.forename: Jean Philippe
authors.initials: JP
authors.lastname: Thiran
authors.affiliation: Signal Processing Laboratory, EPFL, Lausanne, Switzerland.
authors.forename: Alessandra
authors.initials: A
authors.lastname: Griffa
authors.affiliation: Service de Radiodiagnostic et Radiologie Interventionnelle, CHUV, Université de Lausanne, Lausanne, Switzerland.
authors.forename: Reto
authors.initials: R
authors.lastname: Meuli
authors.affiliation: Service de Radiodiagnostic et Radiologie Interventionnelle, CHUV, Université de Lausanne, Lausanne, Switzerland.
authors.forename: Patric
authors.initials: P
authors.lastname: Hagmann
authors.affiliation: Service de Neuropsychologie et de Neuroréhabilitation, CHUV, Université de Lausanne, Lausanne, Switzerland. stephanie.clarke@chuv.ch.
authors.forename: Stephanie
authors.initials: S
authors.lastname: Clarke
mesh_terms: D000328:Adult; D001303:Auditory Cortex / Q000033:anatomy & histology*; D002540:Cerebral Cortex / Q000033:anatomy & histology*; D038524:Diffusion Magnetic Resonance Imaging; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008297:Male; D009434:Neural Pathways / Q000033:anatomy & histology; D066127:White Matter / Q000033:anatomy & histology; D055815:Young Adult
keywords: Auditory areas; Cortical connectivity; Human; Lateralization; Parallel and hierarchical processing