The 1990s were proclaimed "the decade of the brain" by the US Congress, and the last fifteen years have certainly seen many new developments in the brain sciences. Indeed some predict that the entire 21st century will be "the century of the brain". Given the undoubted importance of neurodegenerative diseases, mental disorders and other afflictions of the brain, it is not surprising that brain research has come to be seen as one of the great frontiers in the biomedical sciences, alongside developments in genomics and regenerative medicine.

Our understanding of the brain, its development, its functions, its pathologies, is, of course, of crucial importance for individual and public health. Knowledge of brain structure and development, new insights gained from the interactions of the neurosciences with genetics and molecular biology, increasing understanding of brain plasticity and of the potential of neural stem cells, new developments in brain imaging, coupled with hopes about the powers of psychopharmacology, all inspire hopes for major advances in screening, diagnosis and therapy. We are already seeing the results of some of these developments, from the widespread use of psychiatric drugs which claim efficacy based on their precise mode of action in the brain, to major investments across the globe in functional brain imaging. But changing understandings of the brain also have a wider significance, reshaping our views of what we are as human beings, and leading to all kinds of speculations about their implications for issues ranging from criminal responsibility and undesirable conduct to the management of moods and cognitive enhancement.

These wider social questions will form our focus in this concluding discussion, which will take up many of the issues raised in the previous sessions of the conference. Are we seeing the rise of "neurogenetic determinism", or are the brain sciences actually offering us a more complex and nuanced picture of the relations between the social, the biographical, the neuronal and the genetic? What are the implications of moving from a predominantly psychological conception of human beings and their conduct to one which sees human conduct as ultimately grounded in brain processes? In what ways will these developments reshape our practices for understanding and treating mental ill health, now widely argued to be the major public health problem of the developed world for the twenty first century? Does the evidence support the suggestions of some "neuroethicists" that these developments will have major implications for our system of criminal justice, undermining established views of free will and individual responsibility? How might such developments impact upon the understanding and treatment of issues such as childhood naughtiness, juvenile delinquency, addiction and "pathologies of desire"? Will these developments and their implications differ in different cultures and regions? How will they affect the strategies and practices of our social, political and professional authorities as they seek to shape our conduct in practices ranging from the schoolroom to the factory? Have we, at last overcome Cartesian dualism: are we coming to think of our minds and our selves as, in crucial respects constituted by the bodily organ that is our brain, and if so, what are the implications for how we conduct our individual and collective lives?

Nikolas Rose, BIOS- London School of Economics