Neurodegeneration, Königsberg, and the New York City subway

Researchers seeking to understand and treat brain disease have begun to tackle the brain's immense mathematical complexity by adopting new tools for complex system analysis.1 Graph theory refers to a mathematical framework with a rich history of fostering advances across disciplines, from the nano-level to the cosmic scale, and recently graph theoretical techniques have been used to explore the principles of network-based neurodegeneration.2 In this issue of Neurology ® , Agosta et al.3 add to this burgeoning field by providing a detailed analysis of dysfunctional brain organization in the behavioral variant of frontotemporal dementia (bvFTD).