Chronic pain linked to a specific brain pathway, study suggests

A mouse study found a pathway in the insular cortex that appears to sustain chronic pain, and suppressing that pathway reduced pain responses in the animals. Researchers say further study is needed to determine whether the same mechanism applies in humans.

Researchers at the University of Colorado at Boulder studied how temporary pain can become chronic by focusing on a small region of the insular cortex and its connections to sensory regions of the brain. They used a mouse model of sciatic nerve injury to examine changes in brain and spinal cord activity linked to persistent pain. The team used gene-based tools to suppress activity in the identified pathway and observed changes in the animals' pain responses. The authors note the work was done in mice and say further research is required to understand relevance for people. Key findings: - In the mouse model, a pathway from the caudal granular insular cortex (CGIC) to sensory cortex was associated with the persistence of pain signals. - Suppressing activity in that pathway reduced mechanical hypersensitivity (allodynia) and lowered related activity in the spinal cord and brain, even after pain had been established. - The study was reported in The Journal of Neuroscience, and the researchers stated that the applicability of these results to humans is undetermined and requires additional study. Summary: The study identifies a specific brain circuit that helped sustain chronic pain in mice and reports that silencing that circuit reduced pain responses. Undetermined at this time.