The Mind’s Map of the Physique Is Surprisingly Steady—Even after a Limb Is Misplaced

By Katie Kavanagh & Nature journal

A brain-imaging examine of individuals with amputated arms has upended a long-standing perception: that the mind’s map of the physique reorganizes itself to compensate for lacking physique components.

Earlier analysis had prompt that neurons within the mind area holding this inner map, referred to as the first somatosensory cortex, would develop into the neighbouring space of the cortex that beforehand sensed the limb.

However the newest findings, revealed in Nature Neuroscience on 21 August, reveal that the first somatosensory cortex stays remarkably fixed even years after arm amputation. The examine refutes foundational data within the area of neuroscience that dropping a limb ends in a drastic reorganization of this area, the authors say.

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“Just about each neuroscientist has learnt by their textbook that the mind has the capability for reorganization, and that is demonstrated by research on amputees,” says examine senior creator Tamar Makin, a cognitive neuroscientist on the College of Cambridge, UK. However “textbooks will be mistaken”, she provides. “We shouldn’t take something without any consideration, particularly in relation to mind analysis.”

The invention may result in the event of higher prosthetic units, or improved remedies for ache in ‘phantom limbs’ — when folks proceed to sense the amputated limb. It may additionally assist scientists working to revive sensation in individuals who have had amputations.

Mapping cortical plasticity

Research first creator Hunter Schone, a neuroscientist on the College of Pittsburgh in Pennsylvania, says that earlier stories from some folks with amputations had led him and his colleagues to doubt the concept that the mind’s map of the physique is reorganized after amputation. These maps are accountable for processing sensory data, akin to contact or temperature, at particular physique areas. “They might say: ‘I can nonetheless really feel the limb, I can nonetheless transfer particular person fingers of a hand I haven’t had for many years,’” Schone says.

To analyze this contradiction, the researchers adopted three individuals who have been as a consequence of endure amputation of one among their arms. The staff used useful magnetic resonance imaging (fMRI) to map the cortical representations of the physique earlier than the surgical procedure, after which after the amputation for as much as 5 years. It’s the first examine to do that.

Earlier than their amputations, individuals carried out varied actions, akin to tapping their fingers, pursing their lips and flexing their toes whereas inside an fMRI scanner that measured the exercise in numerous components of the mind. This allowed the researchers to create a cortical ‘map’ exhibiting which areas sensed the hand. To check the concept that neighbouring neurons redistribute within the cortex after amputation, additionally they made maps of the adjoining cortical space — on this case, the half that processes sensations from the lips. The individuals repeated this train a number of instances after their amputation, tapping “with their phantom fingers”, says Schone.

The evaluation revealed that the mind’s illustration of the physique was constant after the arm was amputated. Even 5 years after surgical procedure, the cortical map of the lacking hand was nonetheless activated in the identical method as earlier than amputation. There was additionally no proof that the cortical illustration of the lips had shifted into the hand area following amputation — which is what earlier research prompt would occur.

Makin says their examine is “essentially the most decisive direct proof” that the mind’s in-built physique map stays steady after the lack of a limb. “It simply goes in opposition to the foundational data of the sphere,” she says.

Solaiman Shokur, a neuroengineer on the Sant’anna Faculty of Superior Research in Pisa, Italy, says he was shocked to see the proof proven “in such a transparent method” and that the outcomes “contradict one thing that’s believed within the area, and accomplish that to some extent”.

Implications for analysis

Giacomo Valle, a neuroengineer at Chalmers College of Expertise in Gothenburg, Sweden, praised the examine’s methodology and says it “places a remaining dot — or conclusion — on the talk” concerning the mind’s map of the physique following amputation. “That is necessary proof,” he provides.

He says that the findings may have implications for analysis on prosthetic limbs which can be managed by mind–laptop interfaces implanted within the somatosensory cortex. The knowledge is related to the recruitment of volunteers in medical trials of such units and for potential individuals who may profit from mind–laptop interfaces, he says.

The examine authors be aware that their findings additionally clarify why remedies for phantom limb ache aimed toward ‘reversing’ reorganization within the mind’s map have proven restricted success. “Researchers could have missed the profound resilience of cortical representations,” they write.

This text is reproduced with permission and was first revealed on August 21, 2025.

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