Opportunities and Challenges for Psychiatry in the Connectomic Era

Most major psychiatric disorders arise from disturbances of anatomically distributed neural systems rather than isolated dysfunction of circumscribed brain regions. The past decade has witnessed rapid advances in our capacity to measure, map, and model neural connectivity in diverse species and at different resolution scales, from the level of individual neurons and synapses to large-scale systems spanning the entire brain. In this review, we consider how these techniques, when grounded in the theory and methods of network science, can contribute to a biological understanding of mental illness. We focus in particular on attempts to accurately map brain network disturbances in clinical populations and to model the mechanistic causes of these changes. This work suggests that pathology within highly connected hub regions is a consistent finding across a broad array of phenotypically diverse disorders, and that disparate changes in brain network organization can sometimes be explained by a surprisingly small and simple set of mechanisms.