Foot artists have finely tuned ‘toe-maps’

AFP, WASHINGTON

Thu, Sep 12, 2019 - Page 6

Artists who paint with their feet because they were born without arms have individualized areas of the brain assigned to each of their toes, a trait not found in handed people, scientists have reported.

Their paper, published on Tuesday in the journal Cell Reports, raises intriguing questions about brain plasticity early in life: Are humans born with so-called toe-maps that most lose as a result of not using their feet for intricate tasks because they wear shoes? Or, are we born without the trait, but develop it if the body is used in particularly dexterous ways?

The University College London researchers worked with two major foot artists in the UK.

“We’re trying to find the relationship between behavior and how that shapes representations in our brain,” coauthor Daan Wesselink said, specifically the somatosensory cortex.

Body parts are represented within this brain region in a way that roughly follows their position on the body, with the foot artists providing an illuminating boundary case of people who use their toes in ways that most others do not.

The team performed a series of functional magnetic resonance imaging (fMRI) scans on the two foot artists and on nine male volunteers who have arms.

While the limbed volunteers were in the fMRI machine, the scientists touched each of their fingers and found individual spots of brain activity next to each other — but when they touched the toes, they found no organized pattern.

The artists had individualized areas for each of the toes that corresponded to their position on the body — in other words, toe-maps, which are present in non-human primates as well.

Scientists know there is a critical period of brain plasticity early in life when humans are uniquely capable of learning, and it could be that the artists exploited this crucial window to rewire their gray matter.

To try to resolve this question, the researchers next plan to look at amputees. The team hopes to use the findings to investigate whether they can incorporate robotic prostheses onto adults’ body maps.

“Whether it’s the hand or toe, or any body part, we want to understand more about how the brain copes with these different types of changes,” author Harriet Dempsey-Jones said. “Mapping out finger and toe activity in the brain can help advance brain-machine interfaces where the brain learns how to control each digit of a prosthetic.”