Spinal injuries often leave people with paralysed limbs, as commands from their brains can no longer reach the muscles in their arms. So why not bypass the spine entirely? A team from Northwestern University has used a brain decoder to give monkeys control over their temporarily anaesthetised arms. The decoder deciphers the activity in the monkey’s motor cortex (the part of the brain that controls movements), and electrodes in the monkey’s arm stimulate its muscles in the right way. Even though it can’t feel its arm, it can grab a ball using this electronic middle-man.