Amputation Doesn’t Rewrite the Brain’s Body Map

A woman loses her hand, yet her brain doesn’t seem to notice. Months later, when she tries to “move” her phantom fingers, the same pattern of brain activity lights up as it did before surgery.

A study from the University of Cambridge, University College London and the University of Pittsburgh shows that the brain’s body map remains intact after amputation.

The findings published in Nature Neuroscience challenge decades of assumptions about brain reorganization and could reshape how we treat phantom limb pain and design prosthetics.

How does the brain map the body?

The brain holds a map of the body in the somatosensory cortex, and each part of the map handles touch, pain or body position from a specific body part. For years, researchers have thought this map shifts when a limb disappears. Animal studies, such as experiments in monkeys and human studies comparing amputees to others, suggested that neighbouring areas “take over” the now empty zone in the brain.

Still, many amputees report feeling phantom sensations from the lost limb. Imaging also shows that when these individuals think they move their missing limbs, the brain lights up similarly to non-amputees.

The new study followed individuals who were about to undergo a hand amputation, finally enabling researchers to see directly if the brain map changes – or stays the same – after losing a hand.

Brain scans show stable hand maps after amputation

The team followed three adults who were scheduled to have a hand amputated for medical reasons. Each person was scanned using functional magnetic resonance imaging before surgery and  at several points after: 3 months, 6 months, 18 months in one case and 5 years in another. During the scans, participants were asked to move their fingers before the operation, or to try moving their phantom fingers afterwards. They also pursed their lips and moved their toes. For comparison, the team looked at scans from 16 able-bodied controls and 26 people who had lived with amputation for decades.

Surprisingly, the brain maps of the missing hand remained unchanged. Phantom finger movements produced patterns almost identical to those seen before amputation, and this stability lasted for years.

“Because of our previous work, we suspected that the brain maps would be largely unchanged, but the extent to which the map of the missing limb remained intact was jaw-dropping,” said corresponding author Dr. Tamar Makin, a professor of cognitive neuroscience at the MRC Cognition and Brain Unit at the University of Cambridge.

“Bearing in mind that the somatosensory cortex is responsible for interpreting what’s going on within the body, it seems astonishing that it doesn’t seem to know that the hand is no longer there,” she added.

The scans showed that phantom movements triggered real motor activity in the brain, distinct from simply imagining movement.

“We didn’t see any signs of the reorganization that is supposed to happen according to the classical way of thinking. The brain maps remained static and unchanged,” said lead author Dr. Hunter Schone, a neuroscientist at the University of Pittsburgh.

The team also compared their results with 26 long-term amputees and found the same pattern of stable hand and lip maps, even decades after limb loss.

What stable brain maps mean for pain treatment and prosthetics

These findings challenge a long-standing idea in neuroscience: that the brain rewires itself after amputation. Instead, the evidence suggests the somatosensory cortex holds onto a steady internal model of the body, even when parts of it are gone.

This matters for how we think about phantom limb pain. Many therapies have tried to “fix” the brain’s map, with limited success. But the problem may not be in the brain at all.

Why Current Pain Models Continue to Fail Translation

The session will also explore how these human-specific in vitro approaches support the broader transition toward predictive human-specific alternatives to animal models for drug discovery.
View Webinar

Advertisement

“The remaining parts of the nerves – still inside the residual limb – are no longer connected to their end-targets. Without an end-target, the nerves can continue to grow to form a thickening of the nerve tissue and send noisy signals back to the brain,” said Schone.

“The most promising therapies involve rethinking how the amputation surgery is actually performed, for instance grafting the nerves into a new muscle or skin, so they have a new home to attach to,” he added.

The work also brings optimism for prosthetics and brain–computer interfaces. If body maps are constant, then neural control of robotic limbs may be simpler than many thought.

“If the brain rewired itself after amputation, these technologies would fail. If the area that had been responsible for controlling your hand was now responsible for your face, these implants just wouldn’t work. Our findings provide a real opportunity to develop these technologies now,” said co-senior author Dr. Chris Baker, the chief of the unit on learning and plasticity in the Laboratory of Brain and Cognition at the National Institutes of Mental Health.

“Now that we’ve shown these maps are stable, brain-computer interface technologies can operate under the assumption that the body map remains consistent over time,” added Schone.“This study is a powerful reminder that even after limb loss, the brain holds onto the body, waiting for us to reconnect.”

Reference: Schone HR, Mor ROM, Kollamkulam M, et al. Stable cortical body maps before and after arm amputation. Nat Neurosci. 2025. doi: 10.1038/s41593-025-02037-7

This article is a rework of a press release issued by the University of Cambridge. Material has been edited for length and content.