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Insight into how brain structures interact is critical for understanding the principles of functional brain architectures and may lead to better diagnosis and therapy for neuropsychiatric disorders. We recorded, simultaneously, magnetoencephalographic (MEG) signals and subcortical local field potentials (LFP) in a Parkinson's disease (PD) patient with bilateral deep brain stimulation (DBS) electrodes in the subthalamic nucleus (STN). These recordings offer a unique opportunity to characterize interactions between the subcortical structures and the neocortex. However, high-amplitude artefacts appeared in the MEG. These artefacts originated from the percutaneous extension wire, rather than from the actual DBS electrode and were locked to the heart beat. In this work, we show that MEG beamforming is capable of suppressing these artefacts and quantify the optimal regularization required. We demonstrate how beamforming makes it possible to localize cortical regions whose activity is coherent with the STN-LFP, extract artefact-free virtual electrode time-series from regions of interest and localize cortical areas exhibiting specific task-related power changes. This furnishes results that are consistent with previously reported results using artefact-free MEG data. Our findings demonstrate that physiologically meaningful information can be extracted from heavily contaminated MEG signals and pave the way for further analysis of combined MEG-LFP recordings in DBS patients.

Original publication

DOI

10.1016/j.neuroimage.2009.12.115

Type

Journal article

Journal

Neuroimage

Publication Date

01/05/2010

Volume

50

Pages

1578 - 1588

Keywords

Adult, Artifacts, Brain, Cerebral Cortex, Deep Brain Stimulation, Electrodes, Implanted, Fingers, Heart, Humans, Magnetoencephalography, Male, Middle Aged, Motor Activity, Parkinson Disease, Signal Processing, Computer-Assisted, Subthalamic Nucleus