title: Comparison of diffusion tractography and tract-tracing measures of connectivity strength in rhesus macaque connectome.
abstract: With the mapping of macroscale connectomes by means of in vivo diffusion-weighted MR Imaging (DWI) rapidly gaining in popularity, one of the necessary steps is the examination of metrics of connectivity strength derived from these reconstructions. In the field of human macroconnectomics the number of reconstructed fiber streamlines (NOS) is more and more used as a metric of cortico-cortical interareal connectivity strength, but the link between DWI NOS and in vivo animal tract-tracing measurements of anatomical connectivity strength remains poorly understood. In this technical report, we communicate on a comparison between DWI derived metrics and tract-tracing metrics of projection strength. Tract-tracing information on projection strength of interareal pathways was extracted from two commonly used macaque connectome datasets, including (1) the CoCoMac database of collated tract-tracing experiments of the macaque brain and (2) the high-resolution tract-tracing dataset of Markov and Kennedy and coworkers. NOS and density of reconstructed fiber pathways derived from DWI data acquired across 10 rhesus macaques was found to positively correlate to tract-tracing based measurements of connectivity strength across both the CoCoMac and Markov dataset (both P < 0.001), suggesting DWI NOS to form a valid method of assessment of the projection strength of white matter pathways. Our findings provide confidence of in vivo DWI connectome reconstructions to represent fairly realistic estimates of the wiring strength of white matter projections. Our cross-modal comparison supports the notion of in vivo DWI to be a valid methodology for robust description and interpretation of brain wiring.
authors.affiliation: Department of Psychiatry, University Medical Center Utrecht, The Netherlands.|Brain Center Rudolf Magnus, Utrecht, The Netherlands.
authors.forename: Martijn P
authors.initials: MP
authors.lastname: van den Heuvel
authors.affiliation: Department of Psychiatry, University Medical Center Utrecht, The Netherlands.|Brain Center Rudolf Magnus, Utrecht, The Netherlands.
authors.forename: Marcel A
authors.initials: MA
authors.lastname: de Reus
authors.affiliation: Department of Psychology, Northeastern University, Boston, MA, USA.|Psychiatric Neuroimaging Program, Department of Psychiatry, and the Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Charlestown, MA, USA.
authors.forename: Lisa
authors.initials: L
authors.lastname: Feldman Barrett
authors.affiliation: Department of Psychiatry, University Medical Center Utrecht, The Netherlands.|Brain Center Rudolf Magnus, Utrecht, The Netherlands.
authors.forename: Lianne H
authors.initials: LH
authors.lastname: Scholtens
authors.affiliation: Department of Psychiatry, University Medical Center Utrecht, The Netherlands.|Brain Center Rudolf Magnus, Utrecht, The Netherlands.
authors.forename: Fraukje M T
authors.initials: FM
authors.lastname: Coopmans
authors.affiliation: Brain Center Rudolf Magnus, Utrecht, The Netherlands.|Department of Neurology, University Medical Center Utrecht, The Netherlands.
authors.forename: Ruben
authors.initials: R
authors.lastname: Schmidt
authors.affiliation: Department of Neuropharmacology and Neurologic Diseases, Yerkes National Primate Research Center, Atlanta, GA 30329, USA.|Center for Translational Social Neuroscience, Yerkes National Primate Research Center, Atlanta, GA 30329, USA.
authors.forename: Todd M
authors.initials: TM
authors.lastname: Preuss
authors.affiliation: Center for Translational Social Neuroscience, Yerkes National Primate Research Center, Atlanta, GA 30329, USA.|Department of Anthropology, Emory University, Atlanta, GA, USA.|Department of Psychiatry and Behavioral Sciences, Emory University, Atlanta, GA, USA.|Division of Developmental and Cognitive Neuroscience, Yerkes National Primate Research Center, Emory University, Atlanta, GA, USA.
authors.forename: James K
authors.initials: JK
authors.lastname: Rilling
authors.affiliation: Marcus Autism Center, Children's Healthcare of Atlanta, Emory University, Atlanta, GA, USA.|Biomedical Imaging Technology Center, Emory University/Georgia Institute of Technology, Atlanta, GA, USA.
authors.forename: Longchuan
authors.initials: L
authors.lastname: Li
mesh_terms: D000818:Animals; D001271:Atlases as Topic; D001921:Brain / Q000033:anatomy & histology*; D063132:Connectome; D016208:Databases, Factual; D038524:Diffusion Magnetic Resonance Imaging; D056324:Diffusion Tensor Imaging / Q000379:methods*; D005260:Female; D008253:Macaca mulatta / Q000033:anatomy & histology*; D008297:Male; D009434:Neural Pathways / Q000033:anatomy & histology; D056347:Neuroanatomical Tract-Tracing Techniques; D066127:White Matter / Q000033:anatomy & histology
keywords: connectivity; connectome; connectomics; diffusion imaging; macaque; tract tracing; white matter