Table 3.

Priority unresolved scientific and translational questions for the next 3–5 years.

Domain	Key unresolved questions
Biomarker	How to identify stable, causal, and generalizable biomarkers across individuals and over years? How to optimally fuse multimodal signals (EEG, LFP, fMRI, peripheral) to reduce false positives?
Hardware	How to balance power consumption, heat dissipation, wireless bandwidth, and long-term (>10 years) biocompatibility in fully implantable devices?
Algorithm/control	How to integrate explainable AI into real-time clinical decisions without sacrificing accuracy? Which control strategies (MPC, RL, adaptive PID) suit which temporal dynamics?
Clinical translation	What efficacy thresholds and safety benchmarks justify regulatory approval? How to design trials that adequately test superiority over open-loop systems?
Ethics and society	How to protect neural data privacy while enabling algorithm updates? How to allocate responsibility for autonomous device decisions? How to ensure equitable access to cognitive enhancement?