title: Very high-frequency oscillations (over 1000 Hz) of somatosensory-evoked potentials directly recorded from the human brain.
abstract: The aims of this study were to record high-frequency oscillations (HFOs) associated with somatosensory-evoked potentials from subdural electrodes and to investigate their generators and clinical significance. Six patients who underwent long-term subdural electrode monitoring were studied. Somatosensory-evoked potentials were recorded directly from the subdural electrode after stimulation of the median nerve. Bandpass filter was 10 to 10,000 Hz for conventional somatosensory-evoked potential and 500 to 10,000 Hz for HFO. Three types of HFO were recorded. The first component was early HFO (407-926 Hz), which occurred before N20 peak. The second component was late HFO (408-909 Hz), which occurred after N20 peak. In addition, a novel component was recorded with a range from 1,235 to 2,632 Hz, and this component was termed very HFO. Early and late HFOs were recorded from relatively wide areas centering around the primary motor and primary sensory areas, whereas very HFO was localized around the primary sensory areas. In this study, at least three components of HFO could be identified. Only very HFO was localized around primary sensory areas, suggesting a possibility that very HFO may provide an effective method of identifying the central sulcus.
authors: Department of Clinical Laboratory, National Epilepsy Center, Shizuoka Institute of Epilepsy and Neurological Disorders, Shizuoka, Japan. sakura-jscn@umin.net
authors: Yuji
authors: Y
authors: Sakura
authors: Kiyohito
authors: K
authors: Terada
authors: Keiko
authors: K
authors: Usui
authors: Koichi
authors: K
authors: Baba
authors: Naotaka
authors: N
authors: Usui
authors: Shuichi
authors: S
authors: Umeoka
authors: Miyako
authors: M
authors: Yamaguchi
authors: Kazumi
authors: K
authors: Matsuda
authors: Takayasu
authors: T
authors: Tottori
authors: Tadahiro
authors: T
authors: Mihara
authors: Fumihiro
authors: F
authors: Nakamura
authors: Yushi
authors: Y
authors: Inoue
mesh_terms: D000328:Adult; D001931:Brain Mapping; D002540:Cerebral Cortex / Q000503:physiopathology*; D002648:Child; D004558:Electric Stimulation / Q000379:methods; D004567:Electrodes, Implanted; D004569:Electroencephalography / Q000379:methods; D004827:Epilepsy / Q000473:pathology; D005073:Evoked Potentials, Somatosensory / Q000502:physiology*; D005260:Female; D005385:Fingers / Q000503:physiopathology; D006801:Humans; D008297:Male; D011930:Reaction Time; D013355:Subdural Space / Q000503:physiopathology; D055815:Young Adult