Researchers from Oxford University demonstrated that amputees’ brains can remember their missing hands, even 30 years later.
At Oxford University’s Hand & Brain Lab, the researchers used an ultra-high-power MRI scanner to monitor the brain activity of 2 people who lost their left hands 25 to 30 years ago. The scientists also scanned the brains of 11 people who have both hands and are right-handed. They asked each participant to move individual fingers on their left hand, existent or not.
“We found that while there was less brain activity related to the left hand in the amputees, the specific patterns making up the composition of the hand picture still matched well to the 2-handed people in the control group,” study leader Sanne Kikkert said in prepared in remarks.
Previous work led neuroscientists to believe that if the brain was no longer receiving input from a limb, its “picture” of the limb would change or go away completely, the team reported. Their research challenges that long-held belief, based on the vivid phantom experiences that amputees have of their missing limbs.
“We confirmed our findings by working with a 3rd amputee, who had also experienced a loss of any communication between the remaining part of their arm and their brain. Even this person had a residual representation of their missing hand’s fingers, 31 years after their amputation,” Kikkert said.
The team, who published their work in the journal eLife, suggests the findings could have implications for next-generation prostheses, which rely on brain signals to control the prosthetic limb.
“It seems that even, as previously thought, the brain does carry out reorganization when sensory inputs are lost, it does not erase the original function of a brain area,” Kikkert said. “This would remove a barrier to neuro-prosthetics – prosthetic limbs controlled directly by the brain – the assumption that a person would lose the brain area that could control the prosthetic. If the brain retains a representation of the individual fingers, this could be exploited to provide the fine-grained control needed.”