title: Initial demonstration of in vivo tracing of axonal projections in the macaque brain and comparison with the human brain using diffusion tensor imaging and fast marching tractography.
abstract: Diffusion tensor imaging (DTI), a magnetic resonance imaging technique, is used to infer major axonal projections in the macaque and human brain. This study investigates the feasibility of using known macaque anatomical connectivity as a "gold-standard" for the evaluation of DTI tractography methods. Connectivity information is determined from the DTI data using fast marching tractography (FMT), a novel tract-tracing (tractography) method. We show for the first time that it is possible to determine, in an entirely noninvasive manner, anatomical connection pathways and maps of an anatomical connectivity metric in the macaque brain using a standard clinical scanner and that these pathways are consistent with known anatomy. Analogous human anatomical connectivity is also presented for the first time using the FMT method, and the results are compared. The current limitations of the methodology and possibilities available for further studies are discussed.
authors.affiliation: NMR Research Unit, Institute of Neurology, University College London, Queen Square, London WC1N 3BG, United Kingdom.
authors.forename: Geoffrey J M
authors.initials: GJ
authors.lastname: Parker
authors.forename: Klaas E
authors.initials: KE
authors.lastname: Stephan
authors.forename: Gareth J
authors.initials: GJ
authors.lastname: Barker
authors.forename: James B
authors.initials: JB
authors.lastname: Rowe
authors.forename: David G
authors.initials: DG
authors.lastname: MacManus
authors.forename: Claudia A M
authors.initials: CA
authors.lastname: Wheeler-Kingshott
authors.forename: Olga
authors.initials: O
authors.lastname: Ciccarelli
authors.forename: Richard E
authors.initials: RE
authors.lastname: Passingham
authors.forename: Rachel L
authors.initials: RL
authors.lastname: Spinks
authors.forename: Roger N
authors.initials: RN
authors.lastname: Lemon
authors.forename: Robert
authors.initials: R
authors.lastname: Turner
mesh_terms: D000818:Animals; D001369:Axons / Q000000981:diagnostic imaging*; D001931:Brain Mapping / Q000379:methods; D002540:Cerebral Cortex / Q000033:anatomy & histology*; D004058:Diffusion; D005260:Female; D007089:Image Enhancement / Q000379:methods*; D007091:Image Processing, Computer-Assisted / Q000379:methods*; D021621:Imaging, Three-Dimensional; D008252:Macaca fascicularis; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008636:Mesencephalon / Q000033:anatomy & histology*; D009434:Neural Pathways / Q000033:anatomy & histology*; D013045:Species Specificity; D014463:Ultrasonography