title: Different Mode of Afferents Determines the Frequency Range of High Frequency Activities in the Human Brain: Direct Electrocorticographic Comparison between Peripheral Nerve and Direct Cortical Stimulation.
abstract: Physiological high frequency activities (HFA) are related to various brain functions. Factors, however, regulating its frequency have not been well elucidated in humans. To validate the hypothesis that different propagation modes (thalamo-cortical vs. cortico-coritcal projections), or different terminal layers (layer IV vs. layer II/III) affect its frequency, we, in the primary somatosensory cortex (SI), compared HFAs induced by median nerve stimulation with those induced by electrical stimulation of the cortex connecting to SI. We employed 6 patients who underwent chronic subdural electrode implantation for presurgical evaluation. We evaluated the HFA power values in reference to the baseline overriding N20 (earliest cortical response) and N80 (late response) of somatosensory evoked potentials (HFA(SEP(N20)) and HFA(SEP(N80))) and compared those overriding N1 and N2 (first and second responses) of cortico-cortical evoked potentials (HFA(CCEP(N1)) and HFA(CCEP(N2))). HFA(SEP(N20)) showed the power peak in the frequency above 200 Hz, while HFA(CCEP(N1)) had its power peak in the frequency below 200 Hz. Different propagation modes and/or different terminal layers seemed to determine HFA frequency. Since HFA(CCEP(N1)) and HFA induced during various brain functions share a similar broadband profile of the power spectrum, cortico-coritcal horizontal propagation seems to represent common mode of neural transmission for processing these functions.
authors.affiliation: Department of Neurology, Kyoto University Graduate School of Medicine, Kyoto, Japan.
authors.forename: Katsuya
authors.initials: K
authors.lastname: Kobayashi
authors.affiliation: Department of Epilepsy, Movement Disorders and Physiology, Kyoto University Graduate School of Medicine, Kyoto, Japan.
authors.forename: Riki
authors.initials: R
authors.lastname: Matsumoto
authors.affiliation: Human Brain Research Center, Kyoto University Graduate School of Medicine, Kyoto, Japan.
authors.forename: Masao
authors.initials: M
authors.lastname: Matsuhashi
authors.affiliation: Department of Neurology, Kyoto University Graduate School of Medicine, Kyoto, Japan.
authors.forename: Kiyohide
authors.initials: K
authors.lastname: Usami
authors.affiliation: Department of Neurology, Kyoto University Graduate School of Medicine, Kyoto, Japan.
authors.forename: Akihiro
authors.initials: A
authors.lastname: Shimotake
authors.affiliation: Department of Neurosurgery, Kyoto University Graduate School of Medicine, Kyoto, Japan.
authors.forename: Takeharu
authors.initials: T
authors.lastname: Kunieda
authors.affiliation: Department of Neurosurgery, Kyoto University Graduate School of Medicine, Kyoto, Japan.
authors.forename: Takayuki
authors.initials: T
authors.lastname: Kikuchi
authors.affiliation: Department of Neurosurgery, Sapporo Medical University School of Medicine, Sapporo, Hokkaido, Japan.
authors.forename: Nobuhiro
authors.initials: N
authors.lastname: Mikuni
authors.affiliation: Department of Neurosurgery, Kyoto University Graduate School of Medicine, Kyoto, Japan.
authors.forename: Susumu
authors.initials: S
authors.lastname: Miyamoto
authors.affiliation: Human Brain Research Center, Kyoto University Graduate School of Medicine, Kyoto, Japan.
authors.forename: Hidenao
authors.initials: H
authors.lastname: Fukuyama
authors.affiliation: Department of Neurology, Kyoto University Graduate School of Medicine, Kyoto, 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, Kyoto, Japan.
authors.forename: Akio
authors.initials: A
authors.lastname: Ikeda
mesh_terms: D000328:Adult; D000344:Afferent Pathways / Q000502:physiology / Q000503:physiopathology; D001921:Brain / Q000502:physiology / Q000503:physiopathology*; D001931:Brain Mapping; D001932:Brain Neoplasms / Q000503:physiopathology*; D002540:Cerebral Cortex / Q000502:physiology / Q000503:physiopathology; D004558:Electric Stimulation; D000069280:Electrocorticography; D004567:Electrodes, Implanted; D004827:Epilepsy / Q000503:physiopathology*; D005073:Evoked Potentials, Somatosensory; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008475:Median Nerve / Q000502:physiology / Q000503:physiopathology; D010525:Peripheral Nerves / Q000502:physiology / Q000503:physiopathology*; D055815:Young Adult