title: Disrupted Brain Functional Network Architecture in Chronic Tinnitus Patients.
abstract: OBJECTIVE
  Resting-state functional magnetic resonance imaging (fMRI) studies have demonstrated the disruptions of multiple brain networks in tinnitus patients. Nonetheless, several studies found no differences in network processing between tinnitus patients and healthy controls (HCs). Its neural bases are poorly understood. To identify aberrant brain network architecture involved in chronic tinnitus, we compared the resting-state fMRI (rs-fMRI) patterns of tinnitus patients and HCs.
  
  
  METHODS
  Chronic tinnitus patients (n = 24) with normal hearing thresholds and age-, sex-, education- and hearing threshold-matched HCs (n = 22) participated in the current study and underwent the rs-fMRI scanning. We used degree centrality (DC) to investigate functional connectivity (FC) strength of the whole-brain network and Granger causality to analyze effective connectivity in order to explore directional aspects involved in tinnitus.
  
  
  RESULTS
  Compared to HCs, we found significantly increased network centrality in bilateral superior frontal gyrus (SFG). Unidirectionally, the left SFG revealed increased effective connectivity to the left middle orbitofrontal cortex (OFC), left posterior lobe of cerebellum (PLC), left postcentral gyrus, and right middle occipital gyrus (MOG) while the right SFG exhibited enhanced effective connectivity to the right supplementary motor area (SMA). In addition, the effective connectivity from the bilateral SFG to the OFC and SMA showed positive correlations with tinnitus distress.
  
  
  CONCLUSIONS
  Rs-fMRI provides a new and novel method for identifying aberrant brain network architecture. Chronic tinnitus patients have disrupted FC strength and causal connectivity mostly in non-auditory regions, especially the prefrontal cortex (PFC). The current findings will provide a new perspective for understanding the neuropathophysiological mechanisms in chronic tinnitus.
authors.affiliation: Department of Radiology, Nanjing First Hospital, Nanjing Medical University Nanjing, China.
authors.forename: Yu-Chen
authors.initials: YC
authors.lastname: Chen
authors.affiliation: Department of Radiology, Nanjing First Hospital, Nanjing Medical University Nanjing, China.
authors.forename: Yuan
authors.initials: Y
authors.lastname: Feng
authors.affiliation: Department of Otolaryngology, Nanjing First Hospital, Nanjing Medical University Nanjing, China.
authors.forename: Jin-Jing
authors.initials: JJ
authors.lastname: Xu
authors.affiliation: Department of Radiology, Nanjing First Hospital, Nanjing Medical University Nanjing, China.
authors.forename: Cun-Nan
authors.initials: CN
authors.lastname: Mao
authors.affiliation: Department of Endocrinology, Nanjing First Hospital, Nanjing Medical University Nanjing, China.
authors.forename: Wenqing
authors.initials: W
authors.lastname: Xia
authors.affiliation: Department of Radiology, Nanjing First Hospital, Nanjing Medical University Nanjing, China.
authors.forename: Jun
authors.initials: J
authors.lastname: Ren
authors.affiliation: Department of Radiology, Nanjing First Hospital, Nanjing Medical University Nanjing, China.
authors.forename: Xindao
authors.initials: X
authors.lastname: Yin
keywords: chronic tinnitus; degree centrality; effective connectivity; resting-state fMRI