In research involving patients with implantable brain–computer interfaces (BCIs), there is a regulatory gap concerning post-trial responsibilities and duties of sponsors and investigators towards implanted patients. In this article, we analyse the case of patient R, who underwent non-voluntary explantation of an implanted BCI, causing a discontinuation in her sense of agency and self. To clarify the post-trial duties and responsibilities involved in this case, we first define the ontological status of the BCI using both externalist (EXT) and internalist (INT) (...) theories of cognition. We then give particular focus to the theories of extended and embedded cognition, hence considering the BCI either as a constitutive component of the patient’s mind or as a causal supporter of her brain-based cognitive capacities. We argue that patient R can legitimately be considered both as an embedded and extended cognitive agent. Then, we analyse whether the non-voluntary explantation violated patient R’s (neuro)rights to cognitive liberty, mental integrity, psychological continuity and mental privacy. We analyse whether and how different mental ontologies may imply morally relevant differences in interpreting these prima facie neurorights violations and the correlational duties of sponsors and investigators. We conclude that both mental ontologies support the identification of emerging neurorights of the patient and give rise to post-trial obligations of sponsors and investigators to provide for continuous technical maintenance of implanted BCIs that play a significant role in patients’ agency and sense of self. However, we suggest that externalist mental ontologies better capture patient R’s self-conception and support the identification of a more granular form of mental harm and associated neurorights violation, thus eliciting stricter post-trial obligations. (shrink)