title: Surface based analysis of diffusion orientation for identifying architectonic domains in the in vivo human cortex.
abstract: Diffusion tensor MRI is sensitive to the coherent structure of brain tissue and is commonly used to study large-scale white matter structure. Diffusion in gray matter is more isotropic, however, several groups have observed coherent patterns of diffusion anisotropy within the cerebral cortical gray matter. We extend the study of cortical diffusion anisotropy by relating it to the local coordinate system of the folded cerebral cortex. We use 1mm and sub-millimeter isotropic resolution diffusion imaging to perform a laminar analysis of the principal diffusion orientation, fractional anisotropy, mean diffusivity and partial volume effects. Data from 6 in vivo human subjects, a fixed human brain specimen and an anesthetized macaque were examined. Large regions of cortex show a radial diffusion orientation. In vivo human and macaque data displayed a sharp transition from radial to tangential diffusion orientation at the border between primary motor and somatosensory cortex, and some evidence of tangential diffusion in secondary somatosensory cortex and primary auditory cortex. Ex vivo diffusion imaging in a human tissue sample showed some tangential diffusion orientation in S1 but mostly radial diffusion orientations in both M1 and S1.
authors.affiliation: R.M. Lucas Center for Imaging, Radiology, Stanford University, Stanford, CA 94305, USA. mcnabj@stanford.edu
authors.forename: Jennifer A
authors.initials: JA
authors.lastname: McNab
authors.forename: Jonathan R
authors.initials: JR
authors.lastname: Polimeni
authors.forename: Ruopeng
authors.initials: R
authors.lastname: Wang
authors.forename: Jean C
authors.initials: JC
authors.lastname: Augustinack
authors.forename: Kyoko
authors.initials: K
authors.lastname: Fujimoto
authors.forename: Allison
authors.initials: A
authors.lastname: Stevens
authors.forename: Christina
authors.initials: C
authors.lastname: Triantafyllou
authors.forename: Thomas
authors.initials: T
authors.lastname: Janssens
authors.forename: Reza
authors.initials: R
authors.lastname: Farivar
authors.forename: Rebecca D
authors.initials: RD
authors.lastname: Folkerth
authors.forename: Wim
authors.initials: W
authors.lastname: Vanduffel
authors.forename: Lawrence L
authors.initials: LL
authors.lastname: Wald
mesh_terms: D000818:Animals; D016880:Anisotropy; D001931:Brain Mapping / Q000379:methods*; D002540:Cerebral Cortex / Q000033:anatomy & histology* / Q000502:physiology*; D004058:Diffusion; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods*; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods*; D008251:Macaca