title: Network homogeneity reveals decreased integrity of default-mode network in ADHD.
abstract: Examination of spontaneous intrinsic brain activity is drawing increasing interest, thus methods for such analyses are rapidly evolving. Here we describe a novel measure, "network homogeneity", that allows for assessment of cohesiveness within a specified functional network, and apply it to resting-state fMRI data from adult ADHD and control participants. We examined the default mode network, a medial-wall based network characterized by high baseline activity that decreases during attention-demanding cognitive tasks. We found reduced network homogeneity within the default mode network in ADHD subjects compared to age-matched controls, particularly between the precuneus and other default mode network regions. This confirms previously published results using seed-based functional connectivity measures, and provides further evidence that altered precuneus connectivity is involved in the neuropathology of ADHD. Network homogeneity provides a potential alternative method for assessing functional connectivity of specific large-scale networks in clinical populations.
authors.affiliation: The Phyllis Green and Randolph Cōwen Institute for Pediatric Neuroscience, New York University Child Study Center, New York, NY 10016, USA.
authors.forename: Lucina Q
authors.initials: LQ
authors.lastname: Uddin
authors.forename: A M Clare
authors.initials: AM
authors.lastname: Kelly
authors.forename: Bharat B
authors.initials: BB
authors.lastname: Biswal
authors.forename: Daniel S
authors.initials: DS
authors.lastname: Margulies
authors.forename: Zarrar
authors.initials: Z
authors.lastname: Shehzad
authors.forename: David
authors.initials: D
authors.lastname: Shaw
authors.forename: Manely
authors.initials: M
authors.lastname: Ghaffari
authors.forename: John
authors.initials: J
authors.lastname: Rotrosen
authors.forename: Lenard A
authors.initials: LA
authors.lastname: Adler
authors.forename: F Xavier
authors.initials: FX
authors.lastname: Castellanos
authors.forename: Michael P
authors.initials: MP
authors.lastname: Milham
mesh_terms: D000328:Adult; D001289:Attention Deficit Disorder with Hyperactivity / Q000175:diagnosis / Q000503:physiopathology*; D001931:Brain Mapping / Q000379:methods*; D002540:Cerebral Cortex / Q000033:anatomy & histology / Q000503:physiopathology*; D003071:Cognition / Q000502:physiology; D005071:Evoked Potentials / Q000502:physiology; D007839:Functional Laterality / Q000502:physiology; D006179:Gyrus Cinguli / Q000033:anatomy & histology / Q000503:physiopathology; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging / Q000379:methods*; D009415:Nerve Net / Q000033:anatomy & histology / Q000503:physiopathology*; D009434:Neural Pathways / Q000033:anatomy & histology / Q000503:physiopathology; D009483:Neuropsychological Tests; D010296:Parietal Lobe / Q000033:anatomy & histology / Q000503:physiopathology; D011597:Psychomotor Performance / Q000502:physiology; D012815:Signal Processing, Computer-Assisted