Cognitive neuroscience

For the past century and a half both physiologists and neurologists have dissected, probed, recorded from and stimulated the mammalian nervous system with one central goal: to understand how our brains make us who we are. The first hundred years was marked by the steady accretion of theory and evidence from both of these groups: physiologists seeking to describe the cellular foundations of neural function, and neurologists seeking to describe the relationships between cognitive function and gross damage to the organ of behavior. What we believe has spawned the explosive growth of cognitive neuroscience in the past decade is the fact that now, for the first time, these two approaches have begun to meet in a uniquely fertile manner. What we hope this Current Opinion in Neurobiology issue makes clear is that the micro-foundations of neural function are now being used to understand the macroscopic structure of behavior in a way that has never before been possible. As a result, the articles in this issue summarize recent advances that range from functional studies of social cognition to physiological studies of strategic decision-making. Of course the challenge that such a diverse set of inquiries poses for editors is how to organize them into a coherent sequence of articles that both captures the synthetic breadth of cognitive neuroscience today and respects the pre-existing subdisciplines from which this synthesis arises. The usual response to that challenge is to begin with articles on sensory issues in cognitive neuroscience, to proceed through decision-making, and perhaps memory, to motor neuroscience. After having encapsulated the classically defined subdisciplines of the sensory-motor stream in this way, the really exciting material, the 'cognitive' cognitive neuroscience, so to speak, gets bundled together in a final section. Employing this approach is almost unavoidable at this point in the history of brain science (and so we do employ it here), but we believe that neurobiologists must push themselves to recognize the perils of these old divisions. What this traditional format obfuscates is the simple fact that the 'higher-order' functions of the nervous system, cognitive cognitive functions, govern behavior every bit as much as do sensory and motor processes. As the traditional sensory-motor view of physiologists fuses with the cognitive methodologies of neurologists and psychologists, it becomes clear that even the simplest of behaviors is the coherent synthesis of many interacting subsystems. Gone are the days when physiologists could dismiss cognitive functions as irrelevant to simple behaviors and neurologists could dismiss sensory and motor processing as trivial implementation details with no relevance to cognitive function. It is this pressing and simple fact that we hope this exciting set of articles illustrates. We, therefore, begin this issue with three articles that cut across the entire breadth of cognitive neuroscience. Garland (a lawyer) and Glimcher (a neurobiologist) open the issue with a commentary: Cognitive neuroscience and the law. Most neurobiologists do not realize that cognitive experiments being performed today are exerting influences that not only span the neurosciences but extend well beyond the existing boundaries of our field, influencing legal practice in the United States and other western counties. The authors discuss the current legal mechanisms for incorporating scientific insight into legal practice, and raise serious issues that bear on legal practice today. Our hope is that for our readers this article will both cast current cognitive neuroscience within a larger social framework and caution members of our community to consider the social implications of the experiments they conduct and the words they use to describe those experiments. In the next article, From crawling to cognition: analyzing the dynamical interactions among populations of neurons, we move from the broadest social perspective on human behavior to landmark studies of multi-neuronal interaction in an invertebrate, the medicinal leech. In this article Briggman Abarbanel and Kristan describe a new mathematical technique for identifying functional interactions among large populations of neurons that might have a significant impact on cognitive neuroscience at all levels. Their recent studies have focused on understanding how the leech decides whether to swim or crawl while the activity of literally hundreds of neurons is measured simultaneously. Their novel analytical technique enables them to query how ensembles coordinate to control behavior. What is exciting about this technique is that it could overcome a significant obstacle that has dogged researchers working at all levels of cognitive neuroscience; how to deal with too many results. Even more thrilling is that the approach described in this physiological study of the leech could shape neurological studies of humans in the years to come; a development that is typical of the cognitive neurosciences today. The article that follows provides this same kind of broad and influential insight from the opposite side of the neurobiological spectrum. In their article on Generalist genes and cognitive neuroscience, Butcher, Kennedy and Plomin argue that a single set of genes affects most cognitive abilities and disabilities, and that discovery of these genes will pave the way for a systems-level understanding of how genetically driven brain processes work together to affect diverse cognitive abilities and disabilities. In this article the influences of genetics and psychology meet at the cell biological processes that underlie mental ability.