title: Tinnitus- and Task-Related Differences in Resting-State Networks.
abstract: We investigated tinnitus-related differences in functional networks in adults with tinnitus by means of a functional connectivity study. Previously it was found that various networks show differences in connectivity in patients with tinnitus compared to controls. How this relates to patients' ongoing tinnitus and whether the ecological sensory environment modulates connectivity remains unknown.Twenty healthy controls and twenty patients suffering from chronic tinnitus were enrolled in this study. Except for the presence of tinnitus in the patient group, all subjects were selected to have normal or near-normal hearing. fMRI data were obtained in two different functional states. In one set of runs, subjects freely viewed emotionally salient movie fragments ("fixed-state") while in the other they were not performing any task ("resting-state"). After data pre-processing, Principal Component Analysis was performed to obtain 25 components for all datasets. These were fed into an Independent Component Analysis (ICA), concatenating the data across both groups and both datasets, to obtain group-level networks of neural origin, each consisting of spatial maps with their respective time-courses. Subject-specific maps and their time-course were obtained by back-projection (Dual Regression). For each of the components a mixed-effects linear model was composed with factors group (tinnitus vs. controls), task (fixed-state vs. resting state) and their interaction. The neural components comprised the visual, sensorimotor, auditory, and limbic systems, the default mode, dorsal attention, executive-control, and frontoparietal networks, and the cerebellum. Most notably, the default mode network (DMN) was less extensive and shows significantly less connectivity in tinnitus patients than in controls. This group difference existed in both paradigms. At the same time, the DMN was stronger during resting-state than during fixed-state in the controls but not the patients. We attribute this pattern to the unremitting engaging effect of the tinnitus percept.
authors.affiliation: Department of Otorhinolaryngology / Head and Neck Surgery, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands. c.p.lanting@umcg.nl.|Graduate School of Medical Sciences (Research School of Behavioural and Cognitive Neurosciences), University of Groningen, Groningen, The Netherlands. c.p.lanting@umcg.nl.
authors.forename: Cris
authors.initials: C
authors.lastname: Lanting
authors.affiliation: Department of Otorhinolaryngology / Head and Neck Surgery, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands.|Graduate School of Medical Sciences (Research School of Behavioural and Cognitive Neurosciences), University of Groningen, Groningen, The Netherlands.
authors.forename: Aron
authors.initials: A
authors.lastname: WoźAniak
authors.affiliation: Department of Otorhinolaryngology / Head and Neck Surgery, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands.|Graduate School of Medical Sciences (Research School of Behavioural and Cognitive Neurosciences), University of Groningen, Groningen, The Netherlands.
authors.forename: Pim
authors.initials: P
authors.lastname: van Dijk
authors.affiliation: Department of Otorhinolaryngology / Head and Neck Surgery, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands.|Graduate School of Medical Sciences (Research School of Behavioural and Cognitive Neurosciences), University of Groningen, Groningen, The Netherlands.
authors.forename: Dave R M
authors.initials: DRM
authors.lastname: Langers
mesh_terms: D000328:Adult; D002908:Chronic Disease; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009415:Nerve Net / Q000503:physiopathology*; D025341:Principal Component Analysis; D014012:Tinnitus / Q000503:physiopathology*
keywords: Functional connectivity; Independent component analysis; Resting-state fMRI; Tinnitus