Optogenetics, the use of microbial rhodopsins to make the electrical activity of targeted neurons controllable by light, has swept through neuroscience, enabling thousands of scientists to study how specific neuron types contribute to behaviors and pathologies, and how they might serve as novel therapeutic targets. By activating a set of neurons, one can probe what functions they can initiate or sustain, and by silencing a set of neurons, one can probe the functions they are necessary for. We here review the biophysics of these molecules, asking why they became so useful in neuroscience for the study of brain circuitry. We review the history of the field, including early thinking, early experiments, applications of optogenetics, pre-optogenetics targeted neural control tools, and the history of discovering and characterizing microbial rhodopsins. We then review the biophysical attributes of rhodopsins that make them so useful to neuroscience – their classes and structure, their photocycles, their photocurrent magnitudes and kinetics, their action spectra, and their ion selectivity. Our hope is to convey to the reader how specific biophysical properties of these molecules made them especially useful to neuroscientists for a difficult problem – the control of high-speed electrical activity, with great precision and ease, in the brain.

The rise of neurotechnologies, especially in combination with artificial intelligence (AI)-based methods for brain data analytics, has given rise to concerns around the protection of mental privacy, mental integrity and cognitive liberty – often framed as “neurorights” in ethical, legal, and policy discussions. Several states are now looking at including neurorights into their constitutional legal frameworks, and international institutions and organizations, such as UNESCO and the Council of Europe, are taking an active interest in developing international policy and governance guidelines on this issue. However, in many discussions of neurorights the philosophical assumptions, ethical frames of reference and legal interpretation are either not made explicit or conflict with each other. The aim of this multidisciplinary work is to provide conceptual, ethical, and legal foundations that allow for facilitating a common minimalist conceptual understanding of mental privacy, mental integrity, and cognitive liberty to facilitate scholarly, legal, and policy discussions.

The last two decades have seen dramatic growth in the application of procedurally based interventions for treating refractory psychiatric conditions, leading to interest in developing the foundations for the subspecialty of “Interventional Psychiatry.” However, there is cause for concern that the rate of expansion of clinical advances in this field may be outpacing the ability of postgraduate curricula to provide sufficient exposure to and teaching and supervision of these treatments. The paucity of adequately trained practitioners in Interventional Psychiatry further exacerbates inequities in the ability of eligible patients to access and benefit from these approaches. This paper explores the rates of utilization of Interventional Psychiatry treatments, the current state of education in these treatments, and the role that training can play in translating scientific advances in this area to ensure equitable access and maximum impact at a population level. The majority of the discussion is centered on electroconvulsive therapy (ECT), the most established and available of these treatments, highlighting how enhancing education and training in ECT can reduce barriers to its utilization. It is argued that innovations in pedagogical approaches for disseminating the learning of these procedures are needed to increase the current low rates of competency in these treatments and can facilitate the more rapid dissemination of other Interventional Psychiatry approaches and neurotechnologies, such as repetitive transcranial magnetic stimulation, ketamine, deep brain stimulation, and focused ultrasound.

Placebo-controlled trials are the gold standard of evaluating treatment efficacy in clinical research. Neuromodulation is emerging as an important treatment pathway for many neuropsychiatric conditions, and placebo control arms of these trials require careful design with unique considerations (e.g., sham devices that mimic active stimulation, blinding effectiveness). Inherent to placebo-controlled trials are ethical concerns, such as deception, and potential harm of not receiving the active treatment. In this article, we outline important ethical considerations of placebo-controlled trials across neuromodulation approaches and provide recommendations on how ethical principles can be adhered to going forward. We specifically address issues of autonomy and respect for persons, beneficence, and justice. Within the context of this ethical framework, we also discuss factors influencing placebo effects in neuromodulation, the importance of adequate blinding, and alternative trial designs that could be considered.

Geographic, social, political, and economic factors shape access to advanced neurotechnologies, yet little previous research has explored the barriers, enablers, and areas of opportunity for equitable and meaningful access for diverse patient communities across Canada. We applied a mixed-mode approach involving semi-structured interviews and rating scale questions to consult with 24 medical experts who are involved in the care of patients who undergo functional neurosurgery targeting the brain. Seven major themes emerged from the qualitative analysis: Health care system, Neurotechnology features, Patient demographics, Target condition features, Ethics, Upstream barriers and enablers, and Areas of opportunity. Descriptive statistics of the Likert-scale responses suggest that interviewees perceive a disparity between the imperative of access to advanced neurotechnologies for people living in rural and remote areas and the likelihood of achieving such access. The results depict a complex picture of access to functional neurosurgery in Canada with pockets of excellence and a motivation to improve the availability of care for vulnerable populations through the expansion of distributed care models, improved health care system efficiencies, increasing funding and support for patient travel, and increasing awareness about and advocacy for advanced neurotechnologies.

The neurotechnology sector is likely to develop under pressure towards commercialized, nonmedical products and may also undergo market consolidation. This possibility raises ethical, social, and policy concerns about the future responsibility of neurotechnology innovators and companies for high-consequence design decisions. Present-day internet technology firms furnish an instructive example of the problems that arise when providers of communicative technologies become too big for accountability. As a guardrail against the emergence of similar problems, concerned neurotechnologists may wish to draw inspiration from antitrust law and direct efforts, where appropriate, against undue consolidation in the commercial neurotechnology market.

This article examines the emerging possibility of “brain-state transitioning,” in which one brain state is prompted through manipulating the dynamics of the active brain. The technique, still in its infancy, is intended to provide the basis for novel treatments for brain-based disorders. Although a detailed literature exists covering topics around brain-machine interfaces, where targets of brain-based activity include artificial limbs, hardware, and software, there is less concentration on the brain itself as a target for instrumental intervention. This article examines some of the science behind brain-state transitioning, before extending beyond current possibilities in order to explore philosophical and ethical questions about how transitions could be seen to impact on assessment of responsibility and personal identity. It concludes with some thoughts on how best to pursue this nascent approach while accounting for the philosophical and ethical issues.

In the past decade, international actors have launched “brain projects” or “brain initiatives.” One of the emerging technologies enabled by these publicly funded programs is brain-computer interfaces (BCIs), which are devices that allow communication between the brain and external devices like a prosthetic arm or a keyboard. BCIs are poised to have significant impacts on public health, society, and national security. This research presents the first analytical framework that attempts to predict the dissemination of neurotechnologies to both the commercial and military sectors in the United States and China. While China started its project later with less funding, we find that it has other advantages that make earlier adoption more likely. We also articulate national security risks implicit in later adoption, including the inability to set international ethical and legal norms for BCI use, especially in wartime operating environments, and data privacy risks for citizens who use technology developed by foreign actors.

The body-to-head transplant (BHT) planned to be undertaken later this year at China’s Harbin Medical University by neurosurgeons Sergio Canavero and Xiaoping Ren has attracted considerable attention and criticism. The intended operation gives rise to philosophical queries about the body–brain–mind relationship and nature of the subjective self; technical and ethical issues regarding the scientific soundness, safety, and futility of the procedure; the adequacy of prior research; and the relative merit, folly, and/or danger of forging new boundaries of what is biomedically possible. Moreover, that this procedure, which has been prohibited from being undertaken in other countries, has been sanctioned in China brings into stark relief ways that differing social and political values, philosophies, ethics, and laws can affect the scope and conduct of research. Irrespective of whether the BHT actually occurs, the debate it has generated reveals and reflects both the evermore international enterprise of brain science, and the need for neuroethical discourse to include and appreciate multicultural views, values, and voices.

Closed-loop medical devices such as brain-computer interfaces are an emerging and rapidly advancing neurotechnology. The target patients for brain-computer interfaces (BCIs) are often severely paralyzed, and thus particularly vulnerable in terms of personal autonomy, decisionmaking capacity, and agency. Here we analyze the effects of closed-loop medical devices on the autonomy and accountability of both persons (as patients or research participants) and neurotechnological closed-loop medical systems. We show that although BCIs can strengthen patient autonomy by preserving or restoring communicative abilities and/or motor control, closed-loop devices may also create challenges for moral and legal accountability. We advocate the development of a comprehensive ethical and legal framework to address the challenges of emerging closed-loop neurotechnologies like BCIs and stress the centrality of informed consent and refusal as a means to foster accountability. We propose the creation of an international neuroethics task force with members from medical neuroscience, neuroengineering, computer science, medical law, and medical ethics, as well as representatives of patient advocacy groups and the public.

I raise several concerns with Earp and colleagues' analysis of enhancement through neurochemical modulation of love as a key issue in contemporary neuroethics. These include: (i) strengthening their deflation of medicalization concerns by showing how the objection that love should be left outside of the scope of medicine would directly undermine the goal of medicine; (ii) developing stronger analysis of the social and political concerns relevant to neurochemical modulation of love, by exploring and suggesting possible counters to ways in which 'wellbeing' may be used as a tool of oppression; (iii) providing reasons to support a broad need for ecological investigation of, and indeed ecological education concerning, neurotechnology; (iv) suggesting ways in which philosophy, and the humanities more broadly, remain directly relevant to responding effectively to issues in contemporary neuroethics.