# Closed-Loop BCI **Domain:** Brain-Computer Interfaces / Cybernetics **Doc Type:** Concept Node **Maturity:** Established and Evolving **Related:** [[Brain-Computer Interfaces]], [[Neural Decoding]], [[Neural Interface]], [[Cybernetics]] --- ## Definition A **closed-loop BCI** repeatedly acquires neural activity, decodes or evaluates it, produces an output or stimulation, observes the resulting response, and adapts subsequent operation. The person, device, decoder, task, and environment form one feedback system. ## Architectural role Closed-loop performance cannot be understood from decoder accuracy alone. Latency, adaptation, feedback modality, user learning, safety limits, and control authority determine the behavior of the coupled system.