Organized Toe Maps in Extreme Foot Users

Although the fine-grained features of topographic maps in the somatosensory cortex can be shaped by everyday experience, it is unknown whether behavior can support the expression of somatotopic maps where they do not typically occur. Unlike the fingers, represented in all primates, individuated toe maps have only been found in non-human primates. Using 1-mm resolution fMRI, we identify organized toe maps in two individuals born without either upper limb who use their feet to substitute missing hand function and even support their profession as foot artists. We demonstrate that the ordering and structure of the artists’ toe representation mimics typical hand representation. We further reveal “hand-like” features of activity patterns, not only in the foot area but also similarly in the missing hand area. We suggest humans may have an innate capacity for forming additional topographic maps that can be expressed with appropriate experience. [Display omitted] •We ask if extreme behavior can cause the (re)emergence of somatotopic maps•We investigated two foot artists, born without arms•7T fMRI shows individuated maps of up to 5 toes in the artists but not controls•Activity in artists’ foot and hand areas was more “hand-like” than in controls Dempsey-Jones et al. investigate two foot artists, born without arms, asking if a lifetime of radically altered bodily experience can cause new body maps in the brain. We provide evidence that complex toe behavior supports organized “hand-like” activity in the artists’ foot and (missing) hand areas, significantly more so than in controls.