BRAIN-IMAGING STUDIES OF COGNITIVE FUNCTIONS

Little is understood about the brain, the mind and their relationships However, rapid technical advances in brain-imaging devices such as po sitron emission tomography (PET), functional magnetic resonance imagin g, EEC and EMG have increased the capabilities for visualizing the wor king brain, and uncovering the cerebral areas participating in the rea lization of cognitive tasks, and progress in cognitive science has led to a better understanding of the functional architecture of mental ab ilities. There is, therefore, considerable potential for achieving a g reater understanding of the relationships between cognition and cerebr al structures through brain-imaging studies of mental functions. Howev er, these studies are confronted with a series of difficulties related to the assumptions that govern their application, the constraints imp osed by these techniques on the design of cognitive experiments, the c omplexities inherent in establishing relations between cognition and a natomy through physiology, and to the interpretation of patterns of ce rebral activation. In this article, potential difficulties are describ ed drawing essentially on examples from PET studies of cognitive funct ions. Whereas a bright future lies ahead for the study of human brain mapping, many problems still have to be overcome and solved in order t o exploit the full potential of new brain-imaging techniques.