Overview
- UC San Diego–led researchers mapped a cortex-to-brainstem-to-spinal cord circuit that enables placebo-driven pain relief in mice.
- Using new peptide sensors, the team detected bursts of the body’s own opioid signals in the ventrolateral periaqueductal gray, a brainstem hub for pain control.
- With a light-activated form of naloxone that blocks opioid receptors, they showed that stopping signaling in this spot erased both morphine and placebo analgesia.
- Mice trained with a placebo routine for one kind of pain later showed relief across other pain types, including injury pain, indicating cross-modal generalization.
- The authors say refined placebo training could build pain resilience and lessen reliance on opioid drugs, though the findings are preclinical and will need human testing.