Simultaneous MEG and EEG Source Imaging of Electrophysiological Activity in response to Acute Transcranial Photobiomodulation
Transcranial photobiomodulation (tPBM) is a noninvasive neuromodulation technique that improves human cognition.
The effects of tPBM of the right forehead on neurophysiological activity were previously investigated using EEG. Magnetoencephalography (MEG) records extracranial magnetic signals enabling a higher spatial resolution of brain source images. This study presents the first concurrent MEG and EEG measurements of post-tPBM effects across the entire human brain. MEG and EEG scans were concurrently acquired for 6 min before and after 8-min of tPBM delivered using a 1064-nm laser on the right forehead of 25 healthy participants. Group-level changes in both MEG and EEG power spectral density with respect to the baseline (pre-tPBM) were quantified and averaged within each frequency bands, respectively, in sensor space. Constrained modelling was used to generate MEG and EEG source images of 8-min 1064-nm right prefrontal tPBM, followed by cluster-based permutation analysis for family wise error correction (p<0.05). 8-min of tPBM demonstrated significant increases in both the alpha (8-12 Hz) and beta (13-30 Hz) frequency power across multiple cortical regions, as confirmed by both MEG and EEG source images. tPBM-induced oscillations in the beta frequency band were not only located near the prefrontal site but also in remote cerebral regions, including the frontal, parietal, and occipital regions, with a greater emphasis on the ipsilateral side.
The EEG topographies observed in this study were consistent with those reported in the literature. This study provides MEG/EEG evidence of the electrophysiological effects of tPBM in local and distant cortical regions, supporting the potential utility in modulating neurological disease.
Read the full article at the original website
References:
