Congress christened the 1990s "the decade of the brain," and this was apt from the vantage point of the early 21st Century. Great strides were made in both basic and clinical neuroscience. What the current decade may, in retrospect, be remembered for is the growth of neuroscience beyond those two categories, "basic" and "clinical," into a host of new applications. From the measurement of mental processes with functional neuroimaging to their manipulation with ever more selective drugs, the new capabilities of neuroscience raise unprecedented ethical and social issues. These issues must be identified and addressed if society is to benefit from the neuroscience revolution now in progress.
Like the field of genetics, cognitive neuroscience raises questions about the biological foundations of who we are. Indeed, the relation of self and personal identity to the brain is, if anything, more direct than that of self to the genome. In addition, the ethical questions of neuroscience are more urgent, as neural interventions are currently more easily accomplished than genetic interventions. Yet compared to the field of molecular genetics, in which ethical issues have been at the forefront since the days of the 1975 Asilomar meeting on recombinant DNA, relatively little attention has been paid to the ethics of neuroscience.
This situation is changing, as bioethicists and neuroscientists are beginning to explore the emerging social and ethical issues raised by progress in neuroscience. In the Society for Neuroscience's recently formulated mission statement, bioethical issues figure prominently. (1) Numerous articles, meetings, and symposia have appeared on the subject. (2) The term "neuroethics," which originally referred to bioethical issues in clinical neurology, has now been adopted to refer to ethical issues in the technological advances of neuroscience more generally. (3) (Unfortunately, the term is also used to refer to the neural bases of ethical thinking, a different topic. (4))
Neuroethics encompasses a broad and varied set of bioethical issues. Some are similar to those that have arisen previously in biomedicine, such as the safety of new research and treatment methods, the rationing of promising new therapies, and predictive testing for future illnesses when no cure is available (as with Alzheimer's or Huntington's disease). Other neuroethical issues, however, are unique to neuroscience because of the particular subject matter of that field. The brain is the organ of the mind and consciousness, the locus of our sense of selfhood. Interventions in the brain therefore have different ethical implications than interventions in other organs. In addition, our growing knowledge of mind-brain relations is likely to affect our definitions of competence, mental health and illness, and death. Our moral and legal conceptions of responsibility are likewise susceptible to change as our understanding of the physical mechanisms of behavior evolves. Our sense of the privacy and confidentiality of our own thought processes may also be threatened by technologies that can reveal the neural correlates of our innermost thoughts.
Many of the new social and ethical issues in neuroscience result from one of two developments. The first is the ability to monitor brain function in living humans with a spatial and temporal resolution sufficient to capture psychologically meaningful fluctuations of activity. The second is the ability to alter the brain with chemical or anatomical selectivity that is sufficient to induce specific functional changes. For each of these developments, we will review advances in the enabling technology and provide examples of ethically challenging uses of the technology and an analysis of the ethical issues they raise.
The history of modern brain imaging began in the 1970s with computed axial tomography or CAT scans and proceeded at a rapid and accelerating rate for the remaining decades of the twentieth century. …