title: Connexel visualization: a software implementation of glyphs and edge-bundling for dense connectivity data using brainGL.
abstract: The visualization of brain connectivity becomes progressively more challenging as analytic and computational advances begin to facilitate connexel-wise analyses, which include all connections between pairs of voxels. Drawing full connectivity graphs can result in depictions that, rather than illustrating connectivity patterns in more detail, obfuscate patterns owing to the data density. In an effort to expand the possibilities for visualization, we describe two approaches for presenting connexels: edge-bundling, which clarifies structure by grouping geometrically similar connections; and, connectivity glyphs, which depict a condensed connectivity map at each point on the cortical surface. These approaches can be applied in the native brain space, facilitating interpretation of the relation of connexels to brain anatomy. The tools have been implemented as part of brainGL, an extensive open-source software for the interactive exploration of structural and functional brain data.
authors.affiliation: Max Planck Research Group for Neuroanatomy & Connectivity, Max Planck Institute for Human Cognitive and Brain Sciences Leipzig, Germany.
authors.forename: Joachim
authors.initials: J
authors.lastname: Böttger
authors.affiliation: MEG and Cortical Networks Unit, Max Planck Institute for Human Cognitive and Brain Sciences Leipzig, Germany.
authors.forename: Ralph
authors.initials: R
authors.lastname: Schurade
authors.affiliation: Max Planck Research Group for Neuroanatomy & Connectivity, Max Planck Institute for Human Cognitive and Brain Sciences Leipzig, Germany ; Department of Neurophysics, Max Planck Institute for Human Cognitive and Brain Sciences Leipzig, Germany.
authors.forename: Estrid
authors.initials: E
authors.lastname: Jakobsen
authors.affiliation: Department of Neurology, Max Planck Institute for Human Cognitive and Brain Sciences Leipzig, Germany.
authors.forename: Alexander
authors.initials: A
authors.lastname: Schaefer
authors.affiliation: Max Planck Research Group for Neuroanatomy & Connectivity, Max Planck Institute for Human Cognitive and Brain Sciences Leipzig, Germany.
authors.forename: Daniel S
authors.initials: DS
authors.lastname: Margulies
keywords: connectome; functional connectivity; magnetic resonance imaging; neuroanatomy; visualization software