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.

Multifrequency Dynamics of Cortical Neuromagnetic Activity Underlying Seizure Termination in Absence Epilepsy

“…However, we applied strict criteria and excluded other forms of idiopathic generalized epilepsy to establish a strictly homogeneous group of patients in terms of diagnosis for this study despite the limited sample size. Second, although recent studies have certified that MEG can detect the DBA ( Papadelis et al, 2009 ; Leiken et al, 2014 ), the spatial resolution in the DBA on MEG remains debatable. In several studies, although the activities of the DBA were mainly regarded as the activities of the thalamus ( Wu et al, 2017b ; Jiang et al, 2019 ), we cannot rule out the possibility of artifacts and noise, which may disturb our results.…”

Localization of the Epileptogenic Zone Using High Frequency Oscillations

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High Frequency Neuromagnetic Signals: A New Biomarker for Localizing Epileptic Areas Running Title: High-Frequency Neuromagnetic Signals in Epilepsy

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