Epileptiform discharges and neuronal plasticity in the acute peri-infarct cortex of rats.
While the peri-infarct cortex is thought to be responsible for functional recovery, the site is also a strong candidate for post-stroke seizures. Since it is crucial to identify the conditions when the site is changed with such beneficial or detrimental results, the peri-infarct changes were investigated before and just after inducing a focal infarct on rat cortex. The receptive fields in the peri-infarct cortex began to increase a few hours after the infarct, and reached a statistical significance at 6 hours (Dunnett post hoc tests; p<0.05). In temporal association with these changes, EEG in the peri-infarct cortex showed epileptiform activities containing large-amplitude spike-and-wave discharges. The gross amplitude, peak-to-peak amplitude and burst frequency showed statistically significant increases within 4 hours, in comparison to those of the controls (Dunnett post hoc tests; p<0.05). FFT power spectrum analyses showed a distinct increase in approximately 25 Hz frequency bands in the post-stroke groups. The homogeneous area of the contralateral hemisphere in the infarct group, in contrast, did not show such plastic or excitability changes. This study demonstrated, for the first time, that the peri-infarct cortex acquires the characteristics of potential epileptogenesis and functional recovery within hours of a stroke.
Fujioka
Hiroshi
H
Department of Neurosurgery, Yamaguchi University Hospital, Yamaguchi 755-8505 , Japan. hyperacute2004@yahoo.co.jp
Kaneko
Hidekazu
H
Fujii
Masami
M
Suzuki
Shinya S
SS
Imoto
Hirochika
H
Nomura
Sadahiro
S
Fujisawa
Hirosuke
H
Yamakawa
Takeshi
T
Suzuki
Michiyasu
M
D000200:Action Potentials / Q000502:physiology*; D000344:Afferent Pathways / Q000503:physiopathology; D000704:Analysis of Variance; D000818:Animals; D002544:Cerebral Infarction / Q000150:complications / Q000473:pathology / Q000503:physiopathology; D004195:Disease Models, Animal; D004569:Electroencephalography / Q000379:methods; D004827:Epilepsy / Q000209:etiology*; D005121:Extremities / Q000294:innervation; D007839:Functional Laterality; D008297:Male; D009473:Neuronal Plasticity / Q000502:physiology*; D009474:Neurons / Q000502:physiology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D013997:Time Factors