title: Dynamic magnetic source imaging of absence seizure initialization and propagation: a magnetoencephalography study.
abstract: OBJECTIVE
  The present study aims to determine the initialization and propagation of typical absence seizures using magnetoencephalography (MEG).
  
  
  METHODS
  Fourteen drug-naïve children with childhood absence epilepsy (CAE) were studied using a 275-Channel MEG system. The spectral signatures of epileptic activity were assessed using Morlet continuous wavelet transform. Magnetic sources were volumetrically localized using dynamic magnetic source imaging (dMSI) with a slide window at a millisecond temporal resolution.
  
  
  RESULTS
  The initial portion of ictal activity was predominantly located to the left frontal and posterior cortices. The frontal sources were in the left medial prefrontal cortex (MPFC), the pre-supplementary motor area (pre-SMA), the primary motor cortex, and the lateral prefrontal cortex. The posterior cortical sources were predominantly localized to the left precuneus (pC) and the medial occipital cortices (MOC). The ictal activity after the initialization showed involvement of the MPFC and pC of all patients (14/14) and recursive propagation between the frontal (MPFC) and posterior cortices (pC and MOC) via either the medial portion of the brain (9/14) or the thalamus (5/14), respectively.
  
  
  CONCLUSIONS
  The left frontal and posterior (pC and MOC) cortices play a key role in the initialization of epileptic activity in absence seizures. The thalamus plays a key role in the propagation of absence seizures between the frontal and posterior cortical sources. Considering the MPFC and pC are the nodes of the default mode network (DMN), our results support involvement of the DMN in absence seizures.
authors.affiliation: Department of Neurology, Nanjing Brain Hospital, Nanjing Medical University, Nanjing, Jiangsu 210029, China.
authors.forename: Ailiang
authors.initials: A
authors.lastname: Miao
authors.affiliation: Department of Neurology, Nanjing Brain Hospital, Nanjing Medical University, Nanjing, Jiangsu 210029, China.
authors.forename: Lu
authors.initials: L
authors.lastname: Tang
authors.affiliation: MEG Center, Division of Neurology, Cincinnati Children's Hospital Medical Center, 3333 Burnet Avenue, Cincinnati, OH, 45220, USA.
authors.forename: Jing
authors.initials: J
authors.lastname: Xiang
authors.affiliation: Department of Neurology, Nanjing Brain Hospital, Nanjing Medical University, Nanjing, Jiangsu 210029, China.
authors.forename: Qingshan
authors.initials: Q
authors.lastname: Guan
authors.affiliation: Department of Neurology, Nanjing Brain Hospital, Nanjing Medical University, Nanjing, Jiangsu 210029, China.
authors.forename: Huaiting
authors.initials: H
authors.lastname: Ge
authors.affiliation: Department of Neurology, Nanjing Brain Hospital, Nanjing Medical University, Nanjing, Jiangsu 210029, China.
authors.forename: Hongxing
authors.initials: H
authors.lastname: Liu
authors.affiliation: MEG Center, Nanjing Brain Hospital, Nanjing, Jiangsu 210029, China.
authors.forename: Ting
authors.initials: T
authors.lastname: Wu
authors.affiliation: MEG Center, Nanjing Brain Hospital, Nanjing, Jiangsu 210029, China.
authors.forename: Qiqi
authors.initials: Q
authors.lastname: Chen
authors.affiliation: MEG Center, Nanjing Brain Hospital, Nanjing, Jiangsu 210029, China.
authors.forename: Lu
authors.initials: L
authors.lastname: Yang
authors.affiliation: Department of Neurology, Nanjing Children's Hospital, Nanjing, Jiangsu 210029, China.
authors.forename: Xiaopeng
authors.initials: X
authors.lastname: Lu
authors.affiliation: Department of Neurology, Nanjing Children's Hospital, Nanjing, Jiangsu 210029, China.
authors.forename: Zheng
authors.initials: Z
authors.lastname: Hu
authors.affiliation: Department of Neurology, Nanjing Brain Hospital, Nanjing Medical University, Nanjing, Jiangsu 210029, China. Electronic address: lidou2005@126.com.
authors.forename: Xiaoshan
authors.initials: X
authors.lastname: Wang
mesh_terms: D001931:Brain Mapping; D058256:Brain Waves / Q000502:physiology*; D002540:Cerebral Cortex / Q000473:pathology*; D002648:Child; D002675:Child, Preschool; D004569:Electroencephalography; D004832:Epilepsy, Absence / Q000473:pathology*; D005260:Female; D006801:Humans; D021621:Imaging, Three-Dimensional; D008279:Magnetic Resonance Imaging; D015225:Magnetoencephalography; D008297:Male; D017711:Nonlinear Dynamics; D013997:Time Factors
keywords: Childhood absence epilepsy; Default nodes; Dynamic magnetic source imaging; Magnetoencephalography; Real-time spectrograms; Spike and wave discharges