The Phantom Limb Recwire study our brain understanding

Thursday August 21, 2025

NIH scientists and collaborators reveal that the brain preserves its representation of the lost member in the clinical study.

In a primary study of its kind, researchers have found that the brain control center for a lost appendage can persist long after surgical amputation, which contrasts strongly with long -standing theories on the capacity of the brain to reorganize, also known as plasticity. Scientists from the National Institutes of Health (NIH) and their colleagues examined the activity of the human brain before and after the amputation of the arm and found that the loss of a member does not cause a large -scale cerebral overhaul. Published in the journal Nature neuroscience, This study offers new knowledge on the mysterious syndrome of ghost members and could help guide the development of neuroprosthetics and pain treatments for people with loss of members.

A team of scientists from NIH and the University College London acted on a unique window window, running mRI scans on three participants during the months preceding a planned amputation (carried out for separate medical purposes), then up to five years later.

“It is not often that you have the possibility of conducting a study like this, so we wanted to be extremely in-depth,” said co-author Chris Baker, Ph.D., of the National Mental Health Institute (NIMH) of the NIH. “We have addressed our data from various angles and all our results tell a coherent story.”

Different regions of the most external layer of the brain, called cortex, are responsible for the management of specific body parts. A dominant theory among neuroscientists has been that, when a part of the body is damaged or lost, the cortex will remap, the neighboring regions associated with intact parts of the body encroach on newly available real estate.

“For many decades, cortical remapping in response to amputation has been an example of a literal manual of brain plasticity,” said Baker.

However, this corner of neuroscience was not without debate. A point of snack with this theory is the ubiquitous syndrome of ghost members, in which a patient feels lively, often painful sensations, in a now missing end.

Baker and his co-authors have taken this phenomenon as an index that the brain may remember what it has lost. To discover with certainty, the researchers had to do something unprecedented; Compare the brain activity of individuals before and after their amputation.

After many years of active research and patient screening who had to suffer an amputation, the researchers identified three participants who could help answer their questions.

Twice before the amputations of the expected arm, scientists scanned the participants using a special type of MRI, called functional MRI, to map the brain activity triggered by the tapping of the individual fingers. In the months and years following surgeries, the researchers carried out three follow -up analyzes on the participants when they were trying to perform the same tasks, now with their ghost member.

The researchers then compared brain activity in search of major changes between the pre and post-extension data, but it quickly became clear that there was little or no difference. If the authors did not already know when the data had been collected, explained Baker, then they would probably not have been able to make the difference between brain cards.

However, the team analysis was not limited to human eyes. The authors found that an automatic learning algorithm – trained to identify the movements of the finger of the pre -ammpestation data – there was no problem distinguishing the ghost finger after amputation.

The researchers also learned that the nearby brain circuits associated with the movement of lips and feet did not migrate in the territory of the ghost member. Additional analyzes comparing their data to valid control analyzes, as well as other studies entirely, have only continued to strengthen their initial impression; The representation of the brain of the lost lost limb.

These results potentially improve our understanding of the way in which ghost limbs manifest itself and suggest that standard ghost pain treatments – many of which assume cortical reorganization after the loss of members – may be worth rethinking. According to the main author of the study, Hunter Schone, Ph.D., who conducted this research while a student graduated from NIH, the results could also be essential in the way we implement brain computer interface processing technologies.

“This study is a powerful reminder that even after the loss of members, the brain holds the body, almost as if it is waiting to reconnect in a new way,” said Schone. “Now, brain interface technologies in rapid development can work by assuming that the brain’s body card remains coherent over time.

On the National Institutes of Health (NIH): The NIH, the country’s medical research agency, includes 27 institutes and centers and is a component of the American department of health and social services. NIH is the main federal agency that leads and supports basic, clinical and translational medical research, and studies the causes, treatments and remedies for common and rare diseases. For more information on the NIH and its programs, visit www.nih.gov.

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Reference

“Stable cortical cards before and after the amputation of the arm.” Nature neuroscience. 2025. Doi: 10.1038 / S41593-025-02037-7.