Two artists who paint by holding brushes between their toes have finely tuned brain regions that map onto individual toes — a feature not seen in most people.
In humans and other primates, each individual finger is represented by its own sliver in a region of the brain called the somatosensory cortex. Some non-human primates also have maps of toes in their brains, but humans do not.
To find out whether humans who rely on their toes to an extraordinary extent have toe maps, Daan Wesselink at University College London and his colleagues scanned the brains of two men who were born without arms and who use their toes to paint, write and manipulate objects for daily tasks. The scientists found that as they tapped each of either artist’s toes, his brain became active in a distinct area. The researchers did not see such organized activity in the brains of 11 people with hands.
The authors suggest that toe maps are formed in the years before the age of 15. During this crucial period, the brain is most malleable.