title: Subject-level measurement of local cortical coupling.
abstract: The human cortex is highly folded to allow for a massive expansion of surface area. Notably, the thickness of the cortex strongly depends on cortical topology, with gyral cortex sometimes twice as thick as sulcal cortex. We recently demonstrated that global differences in thickness between gyral and sulcal cortex continue to evolve throughout adolescence. However, human cortical development is spatially heterogeneous, and global comparisons lack power to detect localized differences in development or psychopathology. Here we extend previous work by proposing a new measure - local cortical coupling - that is sensitive to differences in the localized topological relationship between cortical thickness and sulcal depth. After estimation, subject-level coupling maps can be analyzed using standard neuroimaging analysis tools. Capitalizing on a large cross-sectional sample (n=932) of youth imaged as part of the Philadelphia Neurodevelopmental Cohort, we demonstrate that local coupling is spatially heterogeneous and exhibits nonlinear development-related trajectories. Moreover, we uncover sex differences in coupling that indicate divergent patterns of cortical topology. Developmental changes and sex differences in coupling support its potential as a neuroimaging phenotype for investigating neuropsychiatric disorders that are increasingly conceptualized as disorders of brain development. R code to estimate subject-level coupling maps from any two cortical surfaces generated by FreeSurfer is made publicly available along with this manuscript.
authors.affiliation: Department of Psychiatry, University of Pennsylvania, Philadelphia, PA 19104, USA; Department of Biostatistics and Epidemiology, University of Pennsylvania, Philadelphia, PA 19104, USA. Electronic address: simonv@mail.med.upenn.edu.
authors.forename: Simon N
authors.initials: SN
authors.lastname: Vandekar
authors.affiliation: Department of Biostatistics and Epidemiology, University of Pennsylvania, Philadelphia, PA 19104, USA.
authors.forename: Russell T
authors.initials: RT
authors.lastname: Shinohara
authors.affiliation: Child Psychiatry Branch, National Institutes of Mental Health, Bethesda, MD 20892, USA.
authors.forename: Armin
authors.initials: A
authors.lastname: Raznahan
authors.affiliation: Department of Psychiatry, University of Pennsylvania, Philadelphia, PA 19104, USA.
authors.forename: Ryan D
authors.initials: RD
authors.lastname: Hopson
authors.affiliation: Department of Psychiatry, University of Pennsylvania, Philadelphia, PA 19104, USA.
authors.forename: David R
authors.initials: DR
authors.lastname: Roalf
authors.affiliation: Department of Psychiatry, University of Pennsylvania, Philadelphia, PA 19104, USA.
authors.forename: Kosha
authors.initials: K
authors.lastname: Ruparel
authors.affiliation: Department of Psychiatry, University of Pennsylvania, Philadelphia, PA 19104, USA; Department of Radiology, University of Pennsylvania, Philadelphia, PA 19104, USA; Philadelphia Veterans Administration Medical Center, Philadelphia, PA 19104, USA.
authors.forename: Ruben C
authors.initials: RC
authors.lastname: Gur
authors.affiliation: Department of Psychiatry, University of Pennsylvania, Philadelphia, PA 19104, USA; Department of Radiology, University of Pennsylvania, Philadelphia, PA 19104, USA.
authors.forename: Raquel E
authors.initials: RE
authors.lastname: Gur
authors.affiliation: Department of Psychiatry, University of Pennsylvania, Philadelphia, PA 19104, USA.
authors.forename: Theodore D
authors.initials: TD
authors.lastname: Satterthwaite
mesh_terms: D000293:Adolescent; D002540:Cerebral Cortex / Q000033:anatomy & histology* / Q000502:physiology*; D002648:Child; D063132:Connectome / Q000379:methods*; D056324:Diffusion Tensor Imaging / Q000379:methods; D005260:Female; D006801:Humans; D008297:Male; D009415:Nerve Net / Q000033:anatomy & histology* / Q000502:physiology*; D009434:Neural Pathways / Q000033:anatomy & histology / Q000502:physiology; D009473:Neuronal Plasticity / Q000502:physiology; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D055815:Young Adult
keywords: Adolescence; Cortex; Cortical thickness; Development; Folding; Gyrification; MRI