Neurotechnology, or devices that let you track your own brain activity, could help you deeply understand your health. But without privacy protections, your innermost thoughts, emotions and desires could be at risk of exploitation, says neurotech and AI ethicist Nita Farahany. She details some of the field's promising potential uses -- like tracking and treating diseases from depression to epilepsy -- and shares concerns about who collects our brain data and how they plan to use it, ultimately calling for the legal recognition of "cognitive liberty" as we connect our brains and minds to technology.