O1-E-9. HFO correlates of cortico-cortical evoked potentials reveal altered excitability in the human epileptic focus

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• 作者：Katsuya Kobayashi ; Riki Matsumoto ; Masao Matsuhashi ; Kiyohide Usami ; Akihiro Shimotake ; Takeharu Kunieda ; Nobuhiro Mikuni ; Susumu Miyamoto ; Hidenao Fukuyama ; Ryosuke Takahashi ; Akio Ikeda
• 刊名：Clinical Neurophysiology
• 出版年：2013
• 出版时间：August, 2013
• 年：2013
• 卷：124
• 期：8
• 页码：e30
• 全文大小：38 K

文摘

By using cortico-cortical evoked potentials [CCEP: early negative (N1) and late negative (N2) components], we aimed to clarify high frequency oscillation (HFO) correlates of CCEPs and its relation to human epileptogenesis. We recruited 12 patients with intractable partial epilepsy who underwent invasive presurgical evaluation with chronic implantation of subdural electrodes. Repetitive single-pulse electrical stimulation (1 Hz) was applied to (1) the seizure onset zone (SOZ) and (2) the control cortex (nSOZ), and CCEPs were recorded from the surrounding cortices within SOZ and nSOZ, respectively. We applied short-time Fourier transform to obtain induced responses at the timing of N1 (HFO_N1) and N2 (HFO_N2) and analyzed the logarithmic power change of HFO_N1 and HFO_N2 in reference to the baseline activity for ripple (120-200 Hz) and fast ripple (>200 Hz) bands. Seventeen clear CCEP responses were recorded for both SOZ and nSOZ across patients. In both SOZ and nSOZ stimulation, HFO_N1 generally showed power increase and HFO_N2 power decrease across the 2 frequency bands. HFO_N1 power at SOZ increased more significantly than that at nSOZ in FR band. The present study suggests HFO correlates of CCEPs could be a surrogate marker of abnormally enhanced cortical excitability in human epileptic focus.