Greater functional connectivity between two brain regions previously implicated in the experience of pain predicts which back-pain patients will still be in pain a year after reporting problems, according to an article published in Nature Neuroscience this week.

Vania Apkarian and colleagues studied patients with an initial episode of back pain over the course of a year. While some patients recovered during this time, the pain persisted in others. Functional and structural brain imaging showed an initial difference in functional connectivity between the nucleus accumbens and the prefrontal cortex that predicted which patients would go on to suffer from chronic pain. The authors also found gradual changes in grey matter density correlated with the experience of pain for an extended period of time.

Previous work has focused on the changes in the peripheral nerves and spinal cord that lead to chronic pain, but these results suggest that the brain may also play a role in the conversion from acute to chronic pain.