Brain stimulation device lets monkeys 'see' shapes without using eyes

Two monkeys are able to "see" and recognise letter shapes generated by arrays of electrodes implanted in their visual cortex rather than relying on light hitting their retina. It is the highest resolution achieved with implants in the brain, rather than the retina. "That's really good news," says Pieter Roelfsema at the Netherlands Institute for Neuroscience, whose team aims to restore some vision to people who have lost their sight. Many research groups around the world are working on restoring some sight in people who are blind by sending signals from a head-mounted camera to arrays of electrodes that stimulate the appropriate nerve cells. There have been numerous trials in people already, and one 60-electrode device, called the Argus II, was approved for use in the US in 2013.