‘Third Thumb’ Human Augmentation Rewires the Brain


With the implementation of robotic upgrades, scientists can see what happens to human neural circuitry.

A project called The Third Thumb has shown how the brain adapts to an extra body part.

  • Spearheaded by Dani Clode of the University College London Plasticity Lab, the research yielded a 3D-printed prosthetic that is controlled by the feet. 
  • Pressure sensors under the big toes detect movement and relay that information via Bluetooth to a watch strap, which has two motos that control the thumb through Bowden cables. Each toe controls one of the thumb’s two degrees of freedom.
  • Clode and her colleagues conducted a study investigating what happens in the brain when people gain an extra digit. The researchers used functional magnetic resonance imaging (fMRI) to scan the brains of volunteers before and after training with the thumb.

The research focused on the primary sensorimotor cortex, the brain region activated when humans move their fingers.

  • Preliminary findings suggest that training with the thumb can affect this region by weakening the hand’s representation in the brain.
  • The study demonstrated the brain’s plasticity, the ability to rewire itself when facing new experiences or circumstances. 

This technology “critically relies on our brain’s ability to learn, adapt and interface with these devices,” write the researchers.

Read the full report.


Science, Futurology, and Analysis