Applying Dimensionality Reduction Techniques in Source-Space Electroencephalography via Template and Magnetic Resonance Imaging-Derived Head Models to Continuously Decode Hand Trajectories

• Published in: Frontiers in human neuroscience Vol. 16; p. 830221
• Main Authors: Srisrisawang, Nitikorn, Müller-Putz, Gernot R.
• Format: Journal Article
• Language: English
• Published: Switzerland Frontiers Research Foundation 24.03.2022; Frontiers Media S.A
• Subjects: Brain research; Calibration; Classification; Cortex (parietal); EEG; Electrodes; Electroencephalography; electroencephalography (EEG); Experiments; frontoparietal network; Head; Human Neuroscience; Information processing; Kinematics; Localization; Magnetic resonance imaging; magnetic resonance imaging (MRI); Mathematical models; Neurosciences; partial least squares regression; Robotics; Sensors; source localization; Statistical analysis; unscented Kalman filter; United States > US; Germany; electroencephalography (EEG); magnetic resonance imaging (MRI); partial least squares regression; frontoparietal network; source localization; movement decoding; unscented Kalman filter
• ISSN: 1662-5161; 1662-5161
• DOI: 10.3389/fnhum.2022.830221

Several studies showed evidence supporting the possibility of hand trajectory decoding from low-frequency electroencephalography (EEG). However, the decoding in the source space via source localization is scarcely investigated. In this study, we tried to tackle the problem of collinearity due to the higher number of signals in the source space by two folds: first, we selected signals in predefined regions of interest (ROIs); second, we applied dimensionality reduction techniques to each ROI. The dimensionality reduction techniques were computing the mean (Mean), principal component analysis (PCA), and locality preserving projections (LPP). We also investigated the effect of decoding between utilizing a template head model and a subject-specific head model during the source localization. The results indicated that applying source-space decoding with PCA yielded slightly higher correlations and signal-to-noise (SNR) ratios than the sensor-space approach. We also observed slightly higher correlations and SNRs when applying the subject-specific head model than the template head model. However, the statistical tests revealed no significant differences between the source-space and sensor-space approaches and no significant differences between subject-specific and template head models. The decoder with Mean and PCA utilizes information mainly from precuneus and cuneus to decode the velocity kinematics similarly in the subject-specific and template head models.