Handy science

Need a hand? An extra finger might do

It’s a famous scene in the 1987 film The Princess Bride: Inigo Montoya finds the six-fingered Count Rugen after a lifetime of searching. As he chants, “My name is Inigo Montoya. You killed my father. Prepare to die,” the two duel to the death.

While science has long studied people with missing limbs, there’s been much less information available about people with extra limbs, let alone extra fingers. In the quest to build better robotic appendages, an international team of scientists reports that a polydactyl person with six fingers is as adept as a person with five and can do things with one hand that people with five fingers need two to do (Nat. Commun. 2019, DOI: 10.1038/s41467-019-10306-w).

“For several years, roboticists have been attempting to develop extra limbs to augment human movement abilities,” write the researchers, led by Etienne Burdet of Imperial College London. “The biomechanics and functionality of the polydactyly hands analyzed in this paper may be used as a blueprint for the development of robotic hands.”

The team was curious: Does the extra finger have its own nerves and muscles? Can the human brain recognize an extra finger and control how it moves in 3-D space?

To answer these questions, the scientists turned to a mother and a son, each with six fingers on both hands. They found that the fingers had independently functioning nerves and muscles. Compared with someone with five fingers, the mother and son were able to manipulate objects in their hands in more ways, and the extra finger added to the coordination needed to move the object within the fingers. And the team showed that the six-fingered people needed only one hand to play a video game that normally involves two hands to control on-screen movements.

So while (spoiler alert!) Rugen’s six fingers couldn’t save him in a sword fight, had that final confrontation occurred via Tetris, The Princess Bride could have had a very different ending (inconceivable!).

Science as art? She nails it

Luisa Torres is a woman who lets her hands do the talking, at least when it comes to science. Torres is an infectious disease and neuroscience researcher who uses nail polish, an art kit, and an Instagram account to illustrate popular topics in science.

“I got interested through a friend who had a nail art kit. We had a girls’ night at her apartment and we tried and I loved it,” she tells Newscripts. “The design looked really crisp, and it looked really unique.”

That girls’ night kit had metal plates with several designs etched on it. She painted them with nail polish, transferred the design to a rubber stamp, and pressed the stamp to her nails. Afterward, she bought her own kit, watched some YouTube videos, and like any true scientist, began experimenting.

She posted her first design last year around Halloween, not long after the 2018 Nobel Prize in Physiology or Medicine was announced for advances in immunotherapy. The design is abstract, she says: a spooky ghost represents the immune system, and googly eyes represent scared cancer cells. But soon she was doing more literal nail art, using her manicure to explain antibiotic resistance, the gut-brain connection, lunar eclipses, and brain cells. Her latest nail art is DNA.

“This was a suggestion from my followers,” she says of the design. “The DNA design was on the plate. The colors I did from a dotting tool, so you can add the dots for the base pairs.”

Her designs have garnered so much attention that she’s working with nail art companies to design science-themed plates—microbes, lab equipment, and even some chemical structures. She’s hopeful some of them will end up in the hands of young women who are interested in beauty, art, and science.

“You can be a girlie girl in science; it’s something you can do and still be a scientist,” she says of her intricate manicures, nailing the idea of #thisiswhatascientistlookslike.

Megha Satyanarayana wrote this week’s column. Please send comments and suggestions to newscripts@acs.org.