Mind-reading devices reveal brain’s secrets

Brain–computer interfaces (BCIs) — implanted devices that are powered by thought alone — can restore the ability to move and speak to people with paralysis. They are also overturning assumptions about how the brain is organised. For example, BCI recordings of single-neuron activity have revealed that brain regions have fuzzier boundaries than was thought. Researchers have also started to show how BCI use changes the brain. Over time, users’ brains seem to become more efficient at controlling the device and require fewer neural resources to do the tasks. For now, the scope of BCI research remains limited, with only small clinical trials.