title: Hyperactive external awareness against hypoactive internal awareness in disorders of consciousness using resting-state functional MRI: highlighting the involvement of visuo-motor modulation.
abstract: Resting-state functional MRI (fMRI) has emerged as a valuable tool to characterize the complex states encompassing disorders of consciousness (DOC). Awareness appears to comprise two coexistent, anticorrelated components named the external and internal awareness networks. The present study hypothesizes that DOC interrupts the balance between the internal and external awareness networks. To gain more understanding of this phenomenon, the present study analyzed resting-state fMRI data from 12 patients with DOC versus 12 healthy age-matched controls. The data were explored using independent component analysis and amplitude of low-frequency fluctuation (ALFF) analysis. The results indicated that DOC deactivated midline areas associated with internal awareness. In addition, external awareness was strengthened in DOC because of increased activation in the insula, lingual gyrus, paracentral and supplementary motor area. The activity patterns suggested strengthened external awareness against weakened internal awareness in DOC. In particular, increased activity found in the insula, lingual gyrus, paracentral and supplementary motor area of patients with DOC implied possible involvement of augmented visuo-motor modulation in these patients. DOC is probably related to hyperactive external awareness opposing hypoactive internal awareness. This unique pattern of brain activity may potentially be a prognostic marker for DOC.
authors.affiliation: Department of Neurosurgery, Beijing Army General Hospital, Beijing, China.
authors.forename: Jiang-Hong
authors.initials: JH
authors.lastname: He
authors.forename: Yi
authors.initials: Y
authors.lastname: Yang
authors.forename: Yi
authors.initials: Y
authors.lastname: Zhang
authors.forename: Si-You
authors.initials: SY
authors.lastname: Qiu
authors.forename: Zhen-Yu
authors.initials: ZY
authors.lastname: Zhou
authors.forename: Yuan-Yuan
authors.initials: YY
authors.lastname: Dang
authors.forename: Yi-Wu
authors.initials: YW
authors.lastname: Dai
authors.forename: Yi-Jun
authors.initials: YJ
authors.lastname: Liu
authors.forename: Ru-Xiang
authors.initials: RX
authors.lastname: Xu
mesh_terms: D000328:Adult; D000367:Age Factors; D001364:Awareness / Q000502:physiology*; D001519:Behavior; D001921:Brain / Q000473:pathology / Q000503:physiopathology; D001931:Brain Mapping; D016022:Case-Control Studies; D003244:Consciousness Disorders / Q000503:physiopathology*; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D009043:Motor Activity / Q000502:physiology*; D012146:Rest; D012727:Sex Characteristics; D014795:Visual Pathways / Q000503:physiopathology*
keywords: disorders of consciousness (DOC); functional MRI; internal and external awareness networks; minimally conscious state; vegetative state