N aney J. Rothwell ytokine neurobiology is now a hot topic Only a few years ago C most neuroscientists were only dimly aware of cytokines and knew little about their function or biological importance. Cytokines, now a huge collection of polypeptides with diverse activities, were until quite recently, studied by those interested in the immune system, inflamma- tion, cancer or infection in peripheral tissues, and did not feature in neuroscience. For example, less than five years ago virtually no refer- ence was made to cytokines in any of the numerous abstracts at the American Society for...