Encouraging Research Finds Brain Adjusts to Third Thumb
Encouraging Research Finds Brain Adjusts to 'Third Thumb'
The expression "all thumbs" has a new meaning for researchers at University College London.
They're using an award-winning graduate project from London's Royal College of Art to examine the brain's response to coping with additional body parts.
The College of Art's project sought to reframe traditional perceptions of prosthetics through the use of a robotic thumb that could be attached to a hand.
"Our study demonstrates that people can quickly learn to control and benefit from an augmentation device without overthinking," Dani Clode (pictured above), the inventor of the robo thumb and a member of the UCL research team studying how the brain adapts to body augmentation, said in a statement.
"We observed that when people used the Third Thumb, their natural hand movements were altered, and they also reported that the robotic thumb felt like an extension of their own body."
If having two thumbs is advantageous, is having three thumbs even more advantageous? Not necessarily, according to Howie Choset, co-director of Carnegie Mellon University's Biorobotics Lab in Pittsburgh.
"Our thumbs are not interchangeable components," he explained to TechNewsWorld. "They are a component of a system."
"Having an extra thumb means nothing," he explained. "It depends on how that thumb functions within the new system."
Toe-Controlled Thumb
The team trained 30 people to use the robo thumb for their experiment and discovered that participants were capable of performing a variety of tasks that required dexterity, such as building a tower of blocks with one hand.
Because the robo thumb can be created using a 3D printer, it is not only relatively simple to manufacture, but also highly customizable.
The device is attached to the hand opposite the natural thumb, just below the pinkie finger. It is controlled by sensors attached beneath the user's big toes. Through a wireless connection, subtle pressure on the sensors manipulates the device.
Over the course of five days, twenty participants were trained to use the robo thumb. They were encouraged to take the device home and use it for daily tasks during that time. According to the researchers, participants wore the device for between two and six hours per day.
Another group of ten participants completed the same training course while wearing a static version of the robo thumb.
In the lab, participants were trained to perform tasks that aided in increasing cooperation between the robo thumb and the hand to which it was attached, such as picking up multiple balls or wine glasses with one hand.
The researchers report that participants quickly picked up on the fundamentals of thumb manipulation, while the training helped them develop motor control, dexterity, and hand-thumb coordination with the device.
At some point, participants may even be able to use the robo thumb while distracted. They could construct a wooden block tower while solving a math problem or while blindfolded, for example.
"Our study is the first to examine the use of an augmentation device outside of a laboratory setting," Paulina Kieliba, the study's first author, said in a statement.
"This is the first study of its kind to be conducted over multiple days of prolonged training and the first to include an untrained comparison group," she continued.
"The success of our study demonstrates the importance of neuroscientists collaborating closely with designers and engineers to ensure that augmentation devices maximize our brains' capacity for learning and adaptation while also being safe to use," she added.
Subtle Brain Changes
Professor Tamar Makin, the study's lead author, noted that while body augmentation is a growing field aimed at enhancing a human's physical capabilities, there is a lack of clarity regarding how our brains can adapt to it.
"By studying people who wore Dani's deftly designed Third Thumb, we sought to address critical questions about whether the human brain can support an additional body part and how technology may affect our brain," she said in a statement.
"Evolution has not prepared us to use an additional body part, and we have discovered that in order to expand our abilities in novel and unexpected ways, the brain's representation of the biological body will need to adapt," she added.
The participants were scanned before and after training using functional magnetic resonance imaging, which measures brain activity by detecting changes in blood flow. Subjects without a robothumb moved their fingers as they were scanned.
The researchers noted in their project abstract that augmentation had an effect on critical aspects of hand representation and motor control. Third Thumb usage weakened the biological hand's natural kinematic synergies. Additionally, brain decoding revealed a mild collapse of the augmented hand's motor representation following training, even in the absence of the Third Thumb.
The researchers discovered subtle changes in how the sensorimotor cortex of the brain represented the hand that was wearing the robo thumb. Normally, the brain distinguishes each finger from the others. The brain activity pattern associated with each finger was less distinct on the robo thumb hands than it was in normal hands.
However, scans taken a week later revealed that the changes in the hand area of the brain had ceased. This indicates that the effects of using the robo thumb on the brain are not long-lasting, although they acknowledged that additional research is needed to confirm that conclusion.
Choset stated that body augmentation will be critical in the future for both handicapped and healthy individuals. "It will provide prostheses for handicapped individuals and healthy individuals who perform tasks that require machine assistance, such as lifting heavy weights."
Kieliba argued that body augmentation could one day be beneficial to society in a variety of ways, such as allowing a surgeon to operate without an assistant or allowing a factory worker to work more efficiently.
"This line of work has the potential to revolutionize the concept of prosthetics, allowing someone who is permanently or temporarily unable to use one hand to perform all tasks with that hand," she explained.
"However, in order to get there," she continued, "we need to continue investigating the complex, interdisciplinary questions about how these devices interact with our brains."
"This is an excellent experiment for elucidating how the human brain works," added Karthik Ramani, a Purdue University professor of electrical and computer engineering.
"We know very little about the human brain," he explained to TechNewsWorld, "and the connection between the hands and the head is critical."
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