title: Hyperexcitability-associated rapid plasticity after a focal cerebral ischemia.
abstract: OBJECTIVE
  This article addresses how neuroplastic changes are initiated after an ischemic stroke.
  
  
  METHODS
  A focal cerebral ischemia was photochemically induced on the primary somatosensory cortex of rats, and in vivo electrophysiological recordings were performed on the peri-infarct cortex before and from 1 to 6 hours after the infarction.
  
  
  RESULTS
  Paired-pulse analysis of evoked field potentials to peripheral electrical stimuli showed statistically significant neuronal hyperexcitability that was associated with rapid expansion of receptive fields (146.1% at 1 hour and 553.6% at 6 hours) as early as 1 hour after the infarction (P<0.05). Current source density analysis revealed increased current sinks in cortical layer II/III.
  
  
  CONCLUSIONS
  Our electrophysiological results showed, for the first time to our knowledge, rapid plastic changes in the peri-infarct cortex during the hyperacute stage of an ischemic stroke. Manipulation of this rapid plasticity may affect subsequent plastic changes.
authors.affiliation: Yamaguchi University School of Medicine, Ube, Yamaguchi, Japan. e909eb@yamaguchi-u.ac.jp
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Fujioka
authors.forename: Hidekazu
authors.initials: H
authors.lastname: Kaneko
authors.forename: Shinya S
authors.initials: SS
authors.lastname: Suzuki
authors.forename: Kunihiko
authors.initials: K
authors.lastname: Mabuchi
mesh_terms: D000818:Animals; D002545:Brain Ischemia / Q000503:physiopathology*; D005071:Evoked Potentials; D008297:Male; D023421:Models, Animal; D009473:Neuronal Plasticity; D051381:Rats; D017207:Rats, Sprague-Dawley