Somatotopic organization of analgesic brainstem circuitry.
Placebo analgesia induced on the face, arm, and leg evoked somatotopically organized activity changes within the lateral PAG and RVM revealed through 7-T functional MRI. This analgesic circuitry organization suggests that stimulating discrete brain circuits can produce pain relief in specific parts of the body or face and provides a platform for targeted analgesic treatment development. ipsi, ipsilateral; MNI, Montreal Neurological Institute; VAS, visual analog scale. Via Science
Researchers at the University of Sydney have found that the human brain has its own natural way of relieving pain, and it works differently for different parts of the body.
Using advanced 7-Tesla MRI technology, the team discovered that areas in the brainstem control pain relief in specific regions. One part helps reduce pain in the face, while another part handles pain in the arms and legs.
This means the brain doesn’t just switch pain off everywhere - it can target exactly where the pain is coming from.
Even more interesting, this natural system doesn’t seem to rely on opioids (the chemicals in strong painkillers). Instead, it may use the body’s own endocannabinoid system, which helps ease pain safely and naturally.
The discovery could lead to new pain treatments that work more precisely and have fewer side effects. It also helps scientists understand how the placebo effect works, as it shows that believing you’ll feel better can activate real, specific parts of the brain .
While more research is needed, this finding gives hope for future non-addictive pain relief options that work with the body’s own systems instead of against them.
Reference:
Crawford, L. S., Tinoco Mendoza, F. A., Robertson, R. V., Meylakh, N., Macey, P. M., Bannister, K., Wager, T. D., Macefield, V. G., Keay, K. A., & Henderson, L. A. (2025). Somatotopic organization of brainstem analgesic circuitry. Science, 389(6763). https://doi.org/10.1126/science.adu8846