title: Magnetoencephalography detection of high-frequency oscillations in the developing brain.
abstract: Increasing evidence from invasive intracranial recordings suggests that the matured brain generates both physiological and pathological high-frequency signals. The present study was designed to detect high-frequency brain signals in the developing brain using newly developed magnetoencephalography (MEG) methods. Twenty healthy children were studied with a high-sampling rate MEG system. Functional high-frequency brain signals were evoked by electrical stimulation applied to the index fingers. To determine if the high-frequency neuromagnetic signals are true brain responses in high-frequency range, we analyzed the MEG data using the conventional averaging as well as newly developed time-frequency analysis along with beamforming. The data of healthy children showed that very high-frequency brain signals (>1000 Hz) in the somatosensory cortex in the developing brain could be detected and localized using MEG. The amplitude of very high-frequency brain signals was significantly weaker than that of the low-frequency brain signals. Very high-frequency brain signals showed a much earlier latency than those of a low-frequency. Magnetic source imaging (MSI) revealed that a portion of the high-frequency signals was from the somatosensory cortex, another portion of the high-frequency signals was probably from the thalamus. Our results provide evidence that the developing brain generates high-frequency signals that can be detected with the non-invasive technique of MEG. MEG detection of high-frequency brain signals may open a new window for the study of developing brain function.
authors.affiliation: Department of Pediatrics, Magnetoencephalography (MEG) Center, Cincinnati Children's Hospital Medical Center , Cincinnati, OH , USA ; Department of Neurology, Cincinnati Children's Hospital Medical Center , Cincinnati, OH , USA.
authors.forename: Kimberly
authors.initials: K
authors.lastname: Leiken
authors.affiliation: Department of Pediatrics, Magnetoencephalography (MEG) Center, Cincinnati Children's Hospital Medical Center , Cincinnati, OH , USA ; Department of Neurology, Cincinnati Children's Hospital Medical Center , Cincinnati, OH , USA.
authors.forename: Jing
authors.initials: J
authors.lastname: Xiang
authors.affiliation: Department of Communication Sciences and Disorders, University of Cincinnati , Cincinnati, OH , USA.
authors.forename: Fawen
authors.initials: F
authors.lastname: Zhang
authors.affiliation: Department of Neurology, Nanjing Brain Hospital, Nanjing Medical University , Jiangsu , China.
authors.forename: Jingping
authors.initials: J
authors.lastname: Shi
authors.affiliation: Department of Pediatrics, Magnetoencephalography (MEG) Center, Cincinnati Children's Hospital Medical Center , Cincinnati, OH , USA ; Department of Neurology, Cincinnati Children's Hospital Medical Center , Cincinnati, OH , USA ; Department of Neurology, Nanjing Brain Hospital, Nanjing Medical University , Jiangsu , China.
authors.forename: Lu
authors.initials: L
authors.lastname: Tang
authors.affiliation: Department of Pediatrics, Magnetoencephalography (MEG) Center, Cincinnati Children's Hospital Medical Center , Cincinnati, OH , USA ; Department of Neurology, Cincinnati Children's Hospital Medical Center , Cincinnati, OH , USA ; Department of Neurology, Nanjing Brain Hospital, Nanjing Medical University , Jiangsu , China.
authors.forename: Hongxing
authors.initials: H
authors.lastname: Liu
authors.affiliation: Department of Neurology, Nanjing Brain Hospital, Nanjing Medical University , Jiangsu , China.
authors.forename: Xiaoshan
authors.initials: X
authors.lastname: Wang
keywords: beamformer; high-frequency oscillations; magnetoencephalography; pediatrics; somatosensory cortex; wavelet