オザキ　イサム   Ozaki Isamu   尾﨑　勇    所属   東邦大学  医学部 医学科    職種   研究員（寄付講座）
論文種別	原著
言語種別	英語
査読の有無	査読あり
表題	High-frequency oscillations and underlying early cortical responses in SEPs and SEFs
掲載誌名	正式名：International Congress Series ISSNコード：0531-5131
巻・号・頁	1232(C),pp.175-180
著者・共著者	Isamu Ozaki,Isao Hashimoto
発行年月	2002/04/01
概要	In order to evaluate the topography of high-frequency oscillations (HFOs&gt 300 Hz) superimposed on the early cortical responses, we recorded somatosensory evoked potentials (SEPs) and magnetic fields (SEFs) following median nerve stimulation. Using a digital band-pass filter (300–1000 Hz), HFOs were extracted from the original wide-band recordings. In SEP study for 12 healthy subjects, HFOs (five to eight peaks, maximal at 600–800 Hz) were discriminated from the preceding P14 far field in all cases, and their phases were reversed between the frontal and contralateral parietal regions. In subjects with a high amplitude P22 potential in original recordings, a single HFO with a maximum at the central region was present, showing no phase reversal over the centro-parietal scalp. In SEF data for 14 normal subjects, we found that the orientations of the current sources for the HFOs and underlying N20m are different and that the HFO source orientations show a more divergent pattern. HFOs are superimposed not only on the tangential N20–P20 but also on the radial P22 (area 1) potential. We suggest that the somatosensory HFOs are possibly generated from a non-pyramidal neuron population while the underlying N20m is generated from the pyramidal neuron population in area 3b. © 2002 Elsevier Science B.V.
DOI	10.1016/S0531-5131(01)00811-1