Studies Identify Brain Circuits for Chronic Pain

Researchers at the University of Colorado Boulder have identified a specific brain circuit that appears to determine whether pain resolves after an injury or persists as a chronic condition. The study, conducted in animal models and published this month, highlights the caudal granular insular cortex, or CGIC, a small region deep within the brain's insula, as a key player in sustaining long-term pain signals.

The findings reveal that the CGIC interacts with the somatosensory cortex and spinal cord to maintain pain perception even after initial tissue damage heals. In experiments with rats that underwent sciatic nerve injury, activating this pathway led to heightened sensitivity where light touch was perceived as painful, a condition known as allodynia. Conversely, silencing the circuit prevented chronic pain from developing or caused existing persistent pain to subside, while leaving immediate acute pain responses intact.

"Our paper used a variety of state-of-the-art methods to define the specific brain circuit crucial for deciding for pain to become chronic and telling the spinal cord to carry out this instruction," said senior author Linda Watkins, a distinguished professor of...