What is the value of human FMRI in CNS drug development?

Functional neuroimaging has the potential to improve the decision-making process in the development of new drugs. With the high cost of failure of compounds in later stages of development, there is a need to establish, early in man, reliable measures of drug activity and efficacy in the brain. Functional magnetic resonance imaging (FMRI) is a tool for serially examining normal and pathological brain function at the systems level. FMRI is helping us to understand therapeutic mechanisms and can provide clinically relevant markers of disease responses to drugs. An analysis of the value of FMRI to aid decision-making requires an appreciation of the techniques and their validation, a task that has begun and which necessitates an investment of its own.