Adaptive closed-loop neurotechnologies, including adaptive deep brain stimulation, responsive neuroprosthetics, and bidirectional brain–computer interfaces, increasingly operate through continuous feedback between neural activity and computational systems, producing functional outcomes that evolve after deployment (Little et al., 2013; Widge et al., 2018; Fleming et al., 2020). Existing neuroethical governance frameworks remain structured around episodic oversight models grounded in pre-deployment authorization, static safety evaluation, and periodic review (WHO, 2021; OECD, 2019). This paper argues that such frameworks exhibit systematic limitations when applied to adaptive closed-loop neurotechnological systems characterized by recursive biological–technological coupling. The central governance failure is identified as temporal mismatch, arising from the divergence between continuously evolving systems and intermittently operating oversight structures (Reason, 1997). This mismatch produces responsibility diffusion, in which accountability becomes fragmented across time, institutional actors, and adaptive processes in ways that exceed conventional models of distributed responsibility (Floridi, 2013; Bleher & Braun, 2022). Building on systems safety theory, neuroethics, and lifecycle governance approaches, the paper develops functional ethics as a continuity-oriented normative framework. This framework is operationalized through the functional ethics lifecycle model, which reconceptualizes governance as a longitudinal process spanning design, deployment, monitoring, maintenance, adaptation, and decommissioning. The paper concludes that adaptive neurotechnology requires a shift from episodic governance toward lifecycle-based ethical infrastructures capable of sustaining responsibility continuity under conditions of ongoing system adaptation.