title: Dimensionless, Scale Invariant, Edge Weight Metric for the Study of Complex Structural Networks.
abstract: High spatial and angular resolution diffusion weighted imaging (DWI) with network analysis provides a unique framework for the study of brain structure in vivo. DWI-derived brain connectivity patterns are best characterized with graph theory using an edge weight to quantify the strength of white matter connections between gray matter nodes. Here a dimensionless, scale-invariant edge weight is introduced to measure node connectivity. This edge weight metric provides reasonable and consistent values over any size scale (e.g. rodents to humans) used to quantify the strength of connection. Firstly, simulations were used to assess the effects of tractography seed point density and random errors in the estimated fiber orientations; with sufficient signal-to-noise ratio (SNR), edge weight estimates improve as the seed density increases. Secondly to evaluate the application of the edge weight in the human brain, ten repeated measures of DWI in the same healthy human subject were analyzed. Mean edge weight values within the cingulum and corpus callosum were consistent and showed low variability. Thirdly, using excised rat brains to study the effects of spatial resolution, the weight of edges connecting major structures in the temporal lobe were used to characterize connectivity in this local network. The results indicate that with adequate resolution and SNR, connections between network nodes are characterized well by this edge weight metric. Therefore this new dimensionless, scale-invariant edge weight metric provides a robust measure of network connectivity that can be applied in any size regime.
authors.affiliation: Department of Physics University of Florida, Gainesville, Florida, United States of America.
authors.forename: Luis M
authors.initials: LM
authors.lastname: Colon-Perez
authors.affiliation: Department of Biology University of Florida, Gainesville, Florida, United States of America.
authors.forename: Caitlin
authors.initials: C
authors.lastname: Spindler
authors.affiliation: Department of Chemistry University of Florida, Gainesville, Florida, United States of America.
authors.forename: Shelby
authors.initials: S
authors.lastname: Goicochea
authors.affiliation: Department of Biochemistry and Molecular Biology University of Florida, Gainesville, Florida, United States of America.
authors.forename: William
authors.initials: W
authors.lastname: Triplett
authors.affiliation: Department of Pediatrics University of Florida, Gainesville, Florida, United States of America.
authors.forename: Mansi
authors.initials: M
authors.lastname: Parekh
authors.affiliation: Department of Natural Science, University of South Carolina Beaufort, Bluffton, South Carolina, United States of America.
authors.forename: Eric
authors.initials: E
authors.lastname: Montie
authors.affiliation: Department of Pediatrics University of Florida, Gainesville, Florida, United States of America.
authors.forename: Paul R
authors.initials: PR
authors.lastname: Carney
authors.affiliation: Department of Clinical Heath Psychology University of Florida, Gainesville, Florida, United States of America.
authors.forename: Catherine
authors.initials: C
authors.lastname: Price
authors.affiliation: Department of Biochemistry and Molecular Biology University of Florida, Gainesville, Florida, United States of America.
authors.forename: Thomas H
authors.initials: TH
authors.lastname: Mareci
mesh_terms: D000818:Animals; D001921:Brain / Q000166:cytology; D001931:Brain Mapping / Q000379:methods*; D038524:Diffusion Magnetic Resonance Imaging; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods*; D009415:Nerve Net / Q000166:cytology; D051381:Rats; D059629:Signal-To-Noise Ratio