Stable brain map of the missing arm persists years after amputation

A small, long-term study conducted with three individuals challenges a foundational assumption in neuroscience: that the brain’s map of the body reorganizes itself after limb loss. By tracking brain activity with MRI before and after arm amputation, researchers found that the somatosensory cortex preserves a highly stable representation of the missing limb for years, even as sensory input to that limb ceases. The findings, published in a leading neuroscience journal, have potential implications for the development of neural prosthetics and for strategies to treat phantom limb pain.

In the study, participants scheduled to have an arm amputated were scanned while they moved their fingers and pursed their lips, tasks designed to probe adjacent areas of the brain’s body map. Follow-up scans were conducted three and six months after surgery, with additional assessments at 18 months for one participant and five years for another. Across all time points, the brain regions corresponding to the hand and the lips remained strikingly similar to their pre-amputation configurations. To validate the result, researchers trained an artificial intelligence model to recognize which finger...