Role of neurobiological factors

The study of the biology of aggression has always been limited by complex research issues and ethical limitations in performing human research. Early research relied on anecdotal reports in the literature and animal models. Anecdotal studies are inherently limited in their generalizability, as are animal studies which may reveal some basic mechanisms of aggression in more primitive animals but are unable to take into account those changes which occur in brain organization with the development of the more complex areas seen in human research. This research has more recently been enhanced by the introduction of neuroradiological devices which can measure the structure of the human brain (e.g., computed tomography [CT] and magnetic resonance imaging [MRI]) and the metabolic unction of the human brain (e.g., positron emission tomography [PET] and functional magnetic resonance imaging [fMRI]) in intact and live human brain, although not when they are showing violent tendencies. This chapter reviews the major trends in this research.