Neurophysiological mechanisms of immersive virtual reality influence segmental motor reflexes

Immersive virtual reality (VR) technologies are being increasingly applied in clinical settings, physiotherapy, and neurorehabilitation due to their potential to modulate neurophysiological functions. However, the mechanistic basis of VRs effects on human motor systems, especially the impact of emotionally charged VR experiences on segmental spinal reflex excitability, remains unclear. This study aimed to compare the effects of immersive VR stimulation with different emotional tones, the Jendrassik maneuver, and transcranial magnetic stimulation on spinal motor center excitability in healthy adults. H-reflex and M-response amplitudes in the soleus muscle were measured during tibial nerve stimulation under control conditions, during the Jendrassik maneuver, subthreshold magnetic stimulation, and while participants viewed VR videos evoking fear, excitement, or relaxation. The experimental design randomized condition order for each participant. The principal finding was that emotionally salient VR content, particularly scenes inducing fear, produced clear lateralized effects on the spinal motor system. Specifically, inhibitory effects on reflex excitability were observed in the dominant limb, while facilitatory changes occurred in the non-dominant limb. These patterns suggest that immersive VR may differentially engage descending modulatory systems, influencing both sympathoadrenal and corticospinal pathways. In contrast, traditional neuromodulatory interventions did not alter reflex parameters compared to control. The results highlight the unique multimodal influence of immersive VR on sensorimotor regulation and support its incorporation into advanced neurorehabilitation protocols.