title: Resolving anatomical and functional structure in human brain organization: identifying mesoscale organization in weighted network representations.
abstract: Human brain anatomy and function display a combination of modular and hierarchical organization, suggesting the importance of both cohesive structures and variable resolutions in the facilitation of healthy cognitive processes. However, tools to simultaneously probe these features of brain architecture require further development. We propose and apply a set of methods to extract cohesive structures in network representations of brain connectivity using multi-resolution techniques. We employ a combination of soft thresholding, windowed thresholding, and resolution in community detection, that enable us to identify and isolate structures associated with different weights. One such mesoscale structure is bipartivity, which quantifies the extent to which the brain is divided into two partitions with high connectivity between partitions and low connectivity within partitions. A second, complementary mesoscale structure is modularity, which quantifies the extent to which the brain is divided into multiple communities with strong connectivity within each community and weak connectivity between communities. Our methods lead to multi-resolution curves of these network diagnostics over a range of spatial, geometric, and structural scales. For statistical comparison, we contrast our results with those obtained for several benchmark null models. Our work demonstrates that multi-resolution diagnostic curves capture complex organizational profiles in weighted graphs. We apply these methods to the identification of resolution-specific characteristics of healthy weighted graph architecture and altered connectivity profiles in psychiatric disease.
authors.affiliation: Kirchhoff Institute for Physics, University of Heidelberg, Heidelberg, Germany.
authors.forename: Christian
authors.initials: C
authors.lastname: Lohse
authors.affiliation: Department of Physics, University of California, Santa Barbara, California, United States of America; Sage Center for the Study of the Mind, University of California, Santa Barbara, California, United States of America; Department of Bioengineering, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America.
authors.forename: Danielle S
authors.initials: DS
authors.lastname: Bassett
authors.affiliation: Department of Psychiatry, University of Minnesota, Minneapolis, Minnesota, United States of America.
authors.forename: Kelvin O
authors.initials: KO
authors.lastname: Lim
authors.affiliation: Department of Physics, University of California, Santa Barbara, California, United States of America.
authors.forename: Jean M
authors.initials: JM
authors.lastname: Carlson
mesh_terms: D000328:Adult; D001921:Brain / Q000033:anatomy & histology* / Q000502:physiology*; D019295:Computational Biology; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D008959:Models, Neurological; D009415:Nerve Net / Q000033:anatomy & histology* / Q000502:physiology*; D009434:Neural Pathways / Q000033:anatomy & histology* / Q000502:physiology*; D012559:Schizophrenia / Q000473:pathology