title: ELUCIDATING BRAIN CONNECTIVITY NETWORKS IN MAJOR DEPRESSIVE DISORDER USING CLASSIFICATION-BASED SCORING.
abstract: Graph theory is increasingly used in the field of neuroscience to understand the large-scale network structure of the human brain. There is also considerable interest in applying machine learning techniques in clinical settings, for example, to make diagnoses or predict treatment outcomes. Here we used support-vector machines (SVMs), in conjunction with whole-brain tractography, to identify graph metrics that best differentiate individuals with Major Depressive Disorder (MDD) from nondepressed controls. To do this, we applied a novel feature-scoring procedure that incorporates iterative classifier performance to assess feature robustness. We found thatsmall-worldness, a measure of the balance between global integration and local specialization, most reliably differentiated MDD from nondepressed individuals. Post-hoc regional analyses suggested that heightened connectivity of the subcallosal cingulate gyrus (SCG) in MDDs contributes to these differences. The current study provides a novel way to assess the robustness of classification features and reveals anomalies in large-scale neural networks in MDD.
authors.affiliation: Neurosciences Program, Stanford University, Stanford, CA, USA ; Department of Psychology, Stanford University, Stanford, CA, USA.
authors.forename: Matthew D
authors.initials: MD
authors.lastname: Sacchet
authors.affiliation: Department of Psychology, Stanford University, Stanford, CA, USA ; Imaging Genetics Center, Inst. for Neuroimaging and Informatics, Keck Sch. of Med. of USC, Los Angeles, CA, USA.
authors.forename: Gautam
authors.initials: G
authors.lastname: Prasad
authors.affiliation: Department of Psychology, Stanford University, Stanford, CA, USA.
authors.forename: Lara C
authors.initials: LC
authors.lastname: Foland-Ross
authors.affiliation: Imaging Genetics Center, Inst. for Neuroimaging and Informatics, Keck Sch. of Med. of USC, Los Angeles, CA, USA.
authors.forename: Paul M
authors.initials: PM
authors.lastname: Thompson
authors.affiliation: Neurosciences Program, Stanford University, Stanford, CA, USA ; Department of Psychology, Stanford University, Stanford, CA, USA.
authors.forename: Ian H
authors.initials: IH
authors.lastname: Gotlib
keywords: Major Depressive Disorder (MDD); graph theoretical analysis; machine learning; small-world; support vector machine (SVM)