Neuromodulation of resting state brain network topography by heterolateral prefrontal transcranial photobiomodulation

This study aims to explore the distinct effects of left and right prefrontal Transcranial Photobiomodulation (tPBM) on brain functional networks and to quantify the neuromodulation responses of functional brain networks constructed from EEG data under stimulation from heterolateral targets. 18 healthy, young, right-handed participants with no history of neuropsychological disorders participated in two tPBM sessions over a 3-week period. Resting-state EEG data were collected before and after tPBM. Functional connectivity, measured by coherence, and graph theory analysis (GTA) were applied to delta, theta, alpha, and beta bands to assess both global and local network topology. 810 nm tPBM targeting the right prefrontal cortex significantly enhanced long-range functional connectivity in the delta, theta, and beta bands. It increased the global clustering coefficient in the delta band and decreased it in the alpha band. In contrast, left prefrontal tPBM mainly influenced theta band connectivity, increasing the global clustering coefficient in the delta band and reducing nodal clustering in the right central region in the theta band and the right temporal region in the beta band. The findings reveal that both left and right prefrontal 810 nm tPBM induce significant neurophysiological changes in brain network topology. However, the neuromodulation effects differ across brain functional connectivity, as well as global and local network topology levels. The findings in this study provide novel insights into the effects of heterolateral target tPBM stimulation on the brain network and suggest that left prefrontal tPBM could be a potential choice for personalized treatment of neuropsychiatric disorders.