Explore
OYour brain plays many tips for us. Phantom Limb, a condition where the amputees feel lively sensations in a member that is no longer there, is one of the most mysterious. Docused for the first time in the 16th century by the French military surgeon Ambroise adorned among soldiers who had lost members in combat, his name was invented only a few hundred years later by the American surgeon of civil war and neurologist renowned Silas Weir Mitchell, who wrote a narrative of popular fiction of the condition in The Atlantic monthly In 1866. The phenomenon has since fascinated.
Recently, a team of researchers revealed the source of sensations of ghost members: the body of the brain body remains largely the same after the loss of a member. The results, which were published in Nature neurosciencedefy the generalized hypothesis according to which the brain of the amputees reclassified to take into account the missing body part and challenge wider notions on the overall plasticity of the adult brain and the capacity for reorganization.
“This study is a powerful reminder that even after the loss of the members, the brain holds the body, almost as if it is waiting to reconnect in a new way,” said the main author, Hunter Schone, who studied when he was a graduate student at the National Institutes of Health, in a press release. Schone is currently a postdoctoral partner in neuro-engineering from the University of Pittsburgh.
The dominant theory for many years is that when a part of the body is lost or damaged, the external layer of the brain, the cortex, is reorganized, with regions dedicated to other parts of the body which take over from the gray matter which is no longer necessary for this missing end. Some scientists thought that this cortical reorganization scheme had actually led to ghost members and associated pain, in part because an influential article published in 1995 showed that amputees with greater changes in their brain tended to feel more pain. But no one had a clear explanation to explain why.
ADVERTISEMENT
Nautilus members benefit from experience without advertising. Connect or join now.
“The brain holds the body.”
Schone and his collaborators found that this cortical reorganization could be a myth. They used an MRI for image the brain of three adults before and up to five years after the amputation of the arm, comparing the activity in the brain during the movement perceived in the hand and in the lips. The brain seemed the same thing after the amputation as before the two parts of the body, even if the movement in the missing fingers was only imagined after having disappeared the arm.
The team evaluated the resulting MRI images not only with their own eyes, but also using an automatic learning algorithm formed to identify the movements of the fingers on individual brain images before amputation. The AI was able to say precisely what a missing finger, the patients thought they were moving after the amputation during the brain sweeping.
The results could help scientists build a neuro-procosthetic for people with amputee members and develop better pain treatments for people who experience pain in their missing members. They could even help us build smarter brain-computer interface technologies.
ADVERTISEMENT
Nautilus members benefit from experience without advertising. Connect or join now.
The human brain, an astonishing organ that it is, can be less agile than we had imagined, at least in the context of amputation. The discovery that sensations such as the ghost member can result from a lack of cortical reorganization could mean that the way our brain will map the physical body is defined, even in the face of a traumatic loss.
Image of lead: Roman Samborskyi / Shutterstock
