title: Absence epilepsy subnetworks revealed by event-related independent components analysis of functional magnetic resonance imaging.
abstract: OBJECTIVE
  The aim of this study was to provide better spatiotemporal description of the brain activity observed during generalized spike-and-wave (GSW) discharges. Simultaneous electroencephalography and functional magnetic resonance imaging (EEG-fMRI) studies of these epileptiform events have shown regional differences in the timing of fMRI signal changes, which suggests activities within multiple interacting networks rather than a single unified network.
  
  
  METHODS
  EEG-fMRI recordings from eight patients with childhood absence epilepsy (CAE) were studied using event-related independent components analysis (eICA). This technique separates the fMRI signal changes observed during GSW discharges into different spatial components, each showing different event-related timing. Unlike standard independent components analysis (ICA), which is applied to the entire fMRI time series, the eICA method is applied only to the event-related time courses at each voxel, which means that only a small number of components are generated that are all explicitly related to the event of interest.
  
  
  RESULTS
  Six eICA components were identified, representing distinct GSW-related subnetworks. Activations were detected in a number of brain regions, including the striatum, which have not previously been reported in association with GSW in CAE patients.
  
  
  CONCLUSIONS
  The eICA results support previous findings that the earliest activity associated with GSW may be in posterior cortical regions and provide new evidence that the thalamostriate network may play a more important role in the generation of GSW than suggested by previous studies.
authors.affiliation: Brain Research Institute, Florey Institute of Neuroscience and Mental Health, Austin Hospital, Heidelberg, Victoria, Australia.
authors.forename: Richard A J
authors.initials: RA
authors.lastname: Masterton
authors.forename: Patrick W
authors.initials: PW
authors.lastname: Carney
authors.forename: David F
authors.initials: DF
authors.lastname: Abbott
authors.forename: Graeme D
authors.initials: GD
authors.lastname: Jackson
mesh_terms: D001921:Brain / Q000098:blood supply* / Q000473:pathology / Q000503:physiopathology*; D001931:Brain Mapping; D002648:Child; D002675:Child, Preschool; D004569:Electroencephalography; D004832:Epilepsy, Absence / Q000473:pathology / Q000503:physiopathology*; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging; D008297:Male; D009434:Neural Pathways / Q000098:blood supply / Q000473:pathology; D010100:Oxygen / Q000097:blood; D025341:Principal Component Analysis
chemical_list: D010100:Oxygen