Immersion in nature attenuates the development of mechanical secondary hyperalgesia: a role for insulo-thalamic effective connectivity

Nature-based social prescribing has been shown to improve physical and mental health and is increasingly used to manage chronic pain using immersive virtual reality (VR). However, the mechanisms of nature-based analgesia during immersive VR experiences remain unclear. In this study, we used experimentally induced sensitisation within central nociceptive pathways using high frequency stimulation (HFS) over the right forearm in 30 healthy participants and tracked the development of secondary hyperalgesia across three conditions: immersive VR nature, non-immersive 2D nature video, and no intervention. Immersive nature VR significantly reduced the development and spread of hyperalgesia, with sustained analgesic effects correlating with perceived presence. Bayesian modelling of neuroimaging endpoints collected separately revealed nature VR induced analgesic effects correlated with insulo-thalamic effective connectivity. We propose that the analgesic effects of nature are likely mediated via top-down endogenous analgesic systems which could be working to reduce the development and spread of heterotopic plasticity in the spinal cord.