Scientists have developed a system that offers patients paralysed by spinal injuries the prospect of regaining the ability to move.
The breakthrough is the work of Chet Moritz and his colleagues at Washington University in Seattle. Writing in this week's Nature the team describe how they have been able to decode the chatter that goes on between nerve cells in the brain's motor area and then route the signals, via a computer, into muscles directly.
The researchers taught monkeys to play a computer video game that involved positioning a cursor on the screen using wrist movements. Local anaesthetic was then used to paralyse the animals' arms whilst an electrode was used to pick up brain cell activity. The activity was fed to a computer which was in turn connected to a muscle stimulator supplying the wrist muscles.
The animals very quickly learned to play the same computer game just by thinking about moving their wrists; the computer picked up on the nerve activity and activated the wrist muscles, enabling the monekys to control the computer.
Interestingly it was clear that the animals' brains were learning to control the computer better as they went along. This suggests that the same trick could work on patients confined to wheelchairs through spinal injury, like the late Christopher Reeve.