title: Network hyperexcitability in a patient with partial reading epilepsy: converging evidence from magnetoencephalography, diffusion tractography, and functional magnetic resonance imaging.
abstract: OBJECTIVE
  The pathophysiological mechanisms of partial reading epilepsy are still unclear. We delineated the spatial-temporal characteristics of reading-induced epileptic spikes and hemodynamic activation in a patient with partial reading epilepsy.
  
  
  METHODS
  Magnetoencephalography (MEG) was recorded during silent letter-by-letter reading, and the source of reading-induced spikes was estimated using equivalent current dipole (ECD) analysis. Diffusion tractography was employed to determine if the white matter pathway connected spike initiation and termination sites. Functional magnetic resonance imaging (fMRI) was employed to determine the spatial pattern of hemodynamic activation elicited by reading.
  
  
  RESULTS
  In 91 spike events, ECDs were clustered in the left posterior basal temporal area (pBTA) during Katakana reading. In 8 of these 91 events, when the patient continued to read >30 min, another ECD cluster appeared in the left ventral precentral gyrus/frontal operculum with a time-difference of ∼24 ms. Probabilistic diffusion tractography revealed that the long segment of the arcuate fasciculus connected these two regions. fMRI conjunction analysis indicated that both Katakana and Kanji reading activated the left pBTA, but Katakana activated the left lateral frontal areas more extensively than Kanji.
  
  
  CONCLUSIONS
  Prolonged reading of Katakana induced hyper-activation of the cortical network involved in normal language function, concurrently serving as the seizure onset and symptomatogenic zones.
  
  
  CONCLUSIONS
  Reflex epilepsy is believed to result from intrinsic hyper-excitability in the cortical regions recruited during behavioral states that trigger seizures. Our case shows that reading epilepsy can arise from a hyperexcitable network of cortical regions. Physiological activation of this network can have cumulative effects, resulting in greater reciprocal network propagation and electroclinical seizures. These effects, in turn, may give insights into the brain networks recruited by reading.
authors.affiliation: Department of Epilepsy, Movement Disorders and Physiology, Kyoto University Graduate School of Medicine, 54 Kawahara-Cho, Shogoin, Sakyo-Ku, Kyoto 606-8507, Japan; Research and Educational Unit of Leaders for Integrated Medical System, 54 Shogoin-Kawahara-Cho, Sakyo-Ku, Kyoto 606-8507, Japan.
authors.forename: Tomoyuki
authors.initials: T
authors.lastname: Fumuro
authors.affiliation: Department of Epilepsy, Movement Disorders and Physiology, Kyoto University Graduate School of Medicine, 54 Kawahara-Cho, Shogoin, Sakyo-Ku, Kyoto 606-8507, Japan. Electronic address: matsumot@kuhp.kyoto-u.ac.jp.
authors.forename: Riki
authors.initials: R
authors.lastname: Matsumoto
authors.affiliation: Department of Epilepsy, Movement Disorders and Physiology, Kyoto University Graduate School of Medicine, 54 Kawahara-Cho, Shogoin, Sakyo-Ku, Kyoto 606-8507, Japan; Department of Neurology, Kyoto University Graduate School of Medicine, 54 Shogoin-Kawahara-Cho, Sakyo-Ku, Kyoto 606-8507, Japan.
authors.forename: Akihiro
authors.initials: A
authors.lastname: Shimotake
authors.affiliation: Research and Educational Unit of Leaders for Integrated Medical System, 54 Shogoin-Kawahara-Cho, Sakyo-Ku, Kyoto 606-8507, Japan; Department of Human Brain Research Center, Kyoto University Graduate School of Medicine, 54 Shogoin-Kawahara-Cho, Sakyo-Ku, Kyoto 606-8507, Japan.
authors.forename: Masao
authors.initials: M
authors.lastname: Matsuhashi
authors.affiliation: Department of Neurology, Kyoto University Graduate School of Medicine, 54 Shogoin-Kawahara-Cho, Sakyo-Ku, Kyoto 606-8507, Japan; Department of Respiratory Care and Sleep Control Medicine, Kyoto University Graduate School of Medicine, 54 Kawahara-Cho, Shogoin, Sakyo-Ku, Kyoto 606-8507, Japan.
authors.forename: Morito
authors.initials: M
authors.lastname: Inouchi
authors.affiliation: Department of Human Brain Research Center, Kyoto University Graduate School of Medicine, 54 Shogoin-Kawahara-Cho, Sakyo-Ku, Kyoto 606-8507, Japan.
authors.forename: Shin-Ichi
authors.initials: S
authors.lastname: Urayama
authors.affiliation: Department of Neurology, Kyoto University Graduate School of Medicine, 54 Shogoin-Kawahara-Cho, Sakyo-Ku, Kyoto 606-8507, Japan.
authors.forename: Nobukatsu
authors.initials: N
authors.lastname: Sawamoto
authors.affiliation: Department of Human Brain Research Center, Kyoto University Graduate School of Medicine, 54 Shogoin-Kawahara-Cho, Sakyo-Ku, Kyoto 606-8507, Japan.
authors.forename: Hidenao
authors.initials: H
authors.lastname: Fukuyama
authors.affiliation: Department of Neurology, Kyoto University Graduate School of Medicine, 54 Shogoin-Kawahara-Cho, Sakyo-Ku, Kyoto 606-8507, Japan.
authors.forename: Ryosuke
authors.initials: R
authors.lastname: Takahashi
authors.affiliation: Department of Epilepsy, Movement Disorders and Physiology, Kyoto University Graduate School of Medicine, 54 Kawahara-Cho, Shogoin, Sakyo-Ku, Kyoto 606-8507, Japan. Electronic address: akio@kuhp.kyoto-u.ac.jp.
authors.forename: Akio
authors.initials: A
authors.lastname: Ikeda
mesh_terms: D000328:Adult; D056324:Diffusion Tensor Imaging / Q000379:methods; D004828:Epilepsies, Partial / Q000175:diagnosis* / Q000503:physiopathology; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods; D015225:Magnetoencephalography / Q000379:methods; D008297:Male; D009415:Nerve Net / Q000503:physiopathology; D011932:Reading
keywords: Diffusion tractography; Functional magnetic resonance imaging; Japanese; Katakana; Magnetoencephalography; Reading epilepsy