Cortical Activation and Functional Connectivity Response to Different Interactive Modes of Virtual Reality (VR)-Induced Analgesia: A Prospective Functional Near-Infrared Spectroscopy (fNIRS) Study.

Aim: Virtual reality (VR) can be analgesic through intercortical modulation. This study investigated neural activities and correlates during different interactive modes.

Methods: Fifteen healthy participants (4M, 11F, age 21.93 ± 0.59 years) underwent functional near-infrared spectroscopy (fNIRS) to compare cortical activation and functional connectivity (FC) across brain regions of interest (ROI) and channels (CH) during VR experiences. In the active mode (AM), participants engaged with the virtual environment through motor actions. In the passive mode (PM), participants stood still with their eyes closed, listening to the virtual environment's music.

Results: A better analgesic effect was observed in the AM (t = 3.572, p = 0.001) with higher visual-sensorimotor cortical activation (t = 2.59 to 3.99, p = <0.001 to 0.015, p-FDR < 0.05). AM showed significant correlations between ratings (pain level and immersion) of VR questionnaire and visual-motor ROIs (r = 0.547 to 0.595, p = 0.013 to 0.038). PM only correlated with pain level and CH 37 (r = 0.608, p = 0.016). FC between S1 and visual-motor-auditory regions was lower in the AM (t = -4.64 to -3.53, p = 0.029 to 0.049).

Conclusion: VR-induced analgesia occurs via augmenting the visual-sensorimotor-auditory cortical activation, reducing S1 connectivity and weakening pain processing.