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The Extra Finger Advantage

The Extra Finger Advantage

finger

In the Simpsons universe, everyone famously has only four fingers on each hand (the configuration is easier to animate). The sole exception is occasional guest star, God, who, as a deity, naturally has five fingers per hand. So, what does it mean when someone has six?
 
On The Simpsons, nothing: there is no character who boasts 12 total fingers. But in the real world, it means you could have some pretty special wiring in your brain. Researchers are looking at folks with polydactyly, whose extra fingers are fully-formed and usable, in an effort to upgrade the dexterity of those of us stuck with only ten digits.
 
The new study is groundbreaking, in that it looks at polydactyly as an advantage. (The condition is traditionally considered a birth defect, and extra digits, manipulatable or no, are frequently removed in infancy.) The University of Freiburg, Imperial College London, and the Université de Lausanne and L’Ecole polytechnique fédérale de Lausanne have joined forces to study how the human brain incorporates the experience of extra fingers.
 
Though the sample size is currently two (a 52-year-old woman and her 17-year-old son), it seems a good start: the participants tied shoelaces, played video games, and typed on a computer keyboard, then had their fMRI’s compared to non-polydactyl subjects or those with an extra finger.
 
“The researchers found that, like non-polydactyl fingers, the extra digits had their own dedicated tendons, muscles, and nerves, as well as extra corresponding brain regions in the motor cortex.
Polydactyl participants also performed better at many tasks than their non-polydactyl counterparts. For instance, they were able to perform some tasks, like tying shoelaces, with only one hand, where two are usually needed. […]

[Senior paper author] Professor [Etienne] Burdet said: ‘The polydactyl individual’s brains were well adapted to controlling extra workload, and even had dedicated areas for the extra fingers. It’s amazing that the brain has the capacity to do this seemingly without borrowing resources from elsewhere.’”
 
Uses for this knowledge could involve things like extra robot arms for a non-polydactyl surgeon, so they could perform procedures without assistance. But this remains a bit pie-in-the-sky: the team acknowledges that artificial limbs won’t have the same familiarity to the user that a flesh-and-blood appendage or finger does. Plus, it’s likely the brain maps of people born with an extra finger expanded to cover said fingers precisely because they were born with them: the brain of, say, a 45-year-old surgeon might lack the plasticity to control an artificial limb with enough dexterity for the job.
 
Nevertheless, this remains a fascinating concept to think about. If I had a future-tech extra robot limb, I’d use it to type fast enough to catch up with my brain. (Or maybe take both dogs for a walk, with a third hand carrying a travel mug of coffee!) Dear reader: what would you use your additional limb for?