Source localization comparison and combination of OPM-MEG and fMRI to detect sensorimotor cortex responses

• Published in: Computer methods and programs in biomedicine Vol. 254; p. 108292
• Main Authors: An, Nan, Gao, Zhenfeng, Li, Wen, Cao, Fuzhi, Wang, Wenli, Xu, Weinan, Wang, Chunhui, Xiang, Min, Gao, Yang, Wang, Dawei, Yu, Dexin, Ning, Xiaolin
• Format: Journal Article
• Language: English
• Published: Ireland Elsevier B.V 01.09.2024
• Subjects: Adult; Algorithms; Brain Mapping - methods; Computer Simulation; fMRI; Humans; Magnetic Resonance Imaging - methods; Magnetoencephalography (MEG); Magnetoencephalography - methods; Male; OPM-MEG; Oscillatory activity; Sensorimotor Cortex - diagnostic imaging; Sensorimotor Cortex - physiology; Spatial localization; Spatial localization; fMRI; Magnetoencephalography (MEG); Oscillatory activity; OPM-MEG
• DOI: 10.1016/j.cmpb.2024.108292
• ISSN: 0169-2607; 1872-7565

The exploration of various neuroimaging techniques have become focal points within the field of neuroscience research. Magnetoencephalography based on optically pumped magnetometers (OPM-MEG) has shown significant potential to be the next generation of functional neuroimaging with the advantages of high signal intensity and flexible sensor arrangement. In this study, we constructed a 31-channel OPM-MEG system and performed a preliminary comparison of the temporal and spatial relationship between magnetic responses measured by OPM-MEG and blood-oxygen-level-dependent signals detected by functional magnetic resonance imaging (fMRI) during a grasping task. For OPM-MEG, the β-band (15–30 Hz) oscillatory activities can be reliably detected across multiple subjects and multiple session runs. To effectively localize the inhibitory oscillatory activities, a source power-spectrum ratio-based imaging method was proposed. This approach was compared with conventional source imaging methods, such as minimum norm-type and beamformer methods, and was applied in OPM-MEG source analysis. Subsequently, the spatial and temporal responses at the source-level between OPM-MEG and fMRI were analyzed. The effectiveness of the proposed method was confirmed through simulations compared to benchmark methods. Our demonstration revealed an average spatial separation of 10.57 ± 4.41 mm between the localization results of OPM-MEG and fMRI across four subjects. Furthermore, the fMRI-constrained OPM-MEG localization results indicated a more focused imaging extent. Taken together, the performance exhibited by OPM-MEG positions it as a potential instrument for functional surgery assessment. •The brain responses measured by OPM-MEG and fMRI were investigated and compared.•A source power-spectrum ratio-based imaging method was proposed and applied.•Simulations and experiments validated the effectiveness of the proposed method.•Fidelities across multiple subjects and runs demonstrated the performance of OPM-MEG.