Brain–machine interfaces (BMIs) have emerged as one of the most promising systems in translational neurotechnology. These devices can be interfaced with the nervous system to decode neural signals (using a range of non-invasive and invasive intracortical arrays and probes) and translate them into commands to control external devices — for example, to enable people with paralysis to restore their movements1,2,3 or improve communication functions4. BMIs have also been explored to induce stimulation therapy for the treatment of neuropsychiatric disorders, as Shanechi and team discuss in this issue. However, most BMI systems still suffer from bulky, invasive hardware and complex system configuration and operation. In addition, they lack robust long-term recording and decoding stability, requiring lengthy and/or recurring calibration by experts, and wireless transmission of neural data remains challenging, as Schalk and colleagues discuss in this issue. As BMIs approach widespread clinical application, in this collection, we aim to critically examine the state of BMI technology, discuss clinical translation aspects, address ethical concerns and ensure that enthusiasm for BMIs does not outpace responsible development and implementation.

One of the most challenging aspects in BMI development is striking the right balance of rapid innovation, technology refinement to ensure safety and efficacy, and technology release (as Herron and colleagues highlight in this issue). Premature translation may expose people to unnecessary risks and potentially undermine public trust in the technology5. However, giving people early access to experimental BMIs would enable them to make informed choices about their own care and potentially benefit from cutting-edge treatments. Thus, given the high stakes involved, the decision to use a BMI should be a collaborative one among patients, caregivers, developers and healthcare providers, on the basis of a thorough understanding of the potential benefits and risks.

As BMIs become more sophisticated, they also raise a host of ethical questions on issues of privacy, data security, personal identity, cognitive liberty, enhancement, fairness, responsibility and liability6. These questions require ongoing dialogue among neuroscientists, technology developers, ethicists, policymakers and the public, and ideally they should be integrated into the design and development process from the beginning, rather than being treated as an afterthought.

These technical and ethical concerns may be addressed by a user-centred approach at all stages of BMI development, that is, by actively involving (and incentivizing) patients and potential users, considering their lived experiences and prioritizing outcomes that meaningfully improve quality of life, such as independence in daily activities or improved communication. In addition, device aesthetics and customizability should be considered, to minimize stigma and improve acceptability.

For BMIs to fulfil their promise of improving lives, they must be accessible to those who need them most. This raises important questions about medical reimbursement policies and healthcare infrastructures. If clinical studies on BMIs are abandoned or discontinued7, users who have come to rely on these devices may be left in a precarious position, having to decide whether to explant the device or continue using it without medical supervision and device maintenance. Open-source hardware and software, standardized interfaces and regulatory frameworks are thus needed to ensure long-term support. Moreover, public–private partnerships and nonprofit organizations may need to be involved to support critical neurotechnologies when commercial entities step away.

Importantly, exaggerated claims may not only mislead the public but also lead to misallocation of resources and inform policy decisions. Thus, researchers, clinicians and journalists should commit to clear, accurate science communication and reporting. This includes acknowledging the time and effort required for development and refinement, clearly distinguishing between laboratory demonstrations and clinically viable applications, and honestly providing information about potential risks.

“By fostering a more nuanced public understanding of BMIs, a justified enthusiasm for the field can be maintained while setting realistic expectations for its development trajectory, without risking disappointment and erosion of trust in the scientific process”

By fostering a more nuanced public understanding of BMIs, a justified enthusiasm for the field can be maintained while setting realistic expectations for its development trajectory, without risking disappointment and erosion of trust in the scientific process.