When minds become data: brain-computer interfaces and the future of mental privacy.

The rapid advancement of brain-computer interfaces (BCIs), particularly adaptive closed-loop systems, presents unprecedented opportunities for medical intervention and human augmentation. At the same time, the growing adoption of applications outside clinical settings also poses significant risks to mental privacy. In this article, we review the current state of neural decoding advancements and their projected trajectory to assess what current and foreseeable technologies can reveal about mental states and the implications for mental privacy. Drawing on a neuroscientific perspective, we clarify the scope and limits of emerging mental privacy risks and argue for a shift in responsibility from reactive regulation to proactive, privacy-embedded design.