What happens at the end of a clinical trial for an investigational neural implant? It may be surprising to learn how difficult it is to answer this question. While new trials are initiated with increasing regularity, relatively little consensus exists on how best to conduct them, and even less on how to ethically end them. The landscape of recent neural implant trials demonstrates wide variability of what happens to research participants after an neural implant trial ends. Some former research participants (...) continue to receive support for their devices (e.g., battery and component replacements, software updates, etc.). Others, when safe, have their neural implants removed through surgical explantation. Still others continue to live with a deactivated neural implant embedded in their body. In the United States, there are no uniform requirements to provide services, of any kind, after an neural implant study ends, and other nations are similarly facing this challenge. The existence of a post-trial gap in an expanding neural implant research ecosystem invites obvious questions: What is owed to neural implant research participants post-trial, and why has providing it been so difficult to accomplish in practice? To take a step forward on this difficult issue, we assembled one group of stakeholders – researchers funded for neuroethics grants by the National Institutes of Health – to explore possible starting points on one topic: ethical guidance for post-trial care of research participants in neural implant trials. Based on shared concerns discussed in the expert workshop the current paper is a call to action. It reports the key areas of convergence from the meeting and highlights important next steps towards developing much needed guidance. (shrink)