Elon Musk's brain-computer interface company Neuralink has finally broken its silence. Since the company was formed in 2016, it has kept its plans secret, but in a presentation on Tuesday night it showed off its vision and explained what the firm has done so far. At the event, the company unveiled a brain-computer interface – a technology that allows machines to read brain activity. Neuralink says its device will have around 3000 surgically implanted electrodes, each of which will be able monitor around 1000 neurons at a time. The electrodes will be attached to around 100 extremely thin threads, between 4 and 6 micrometres wide, which is much less than the width of a hair.