 However, it is not structural but functional MRI (fMRI) that has revolutionized the study of human cognition. fMRI provides information about correlates of neuronal activity, from which neural activity can be inferred. Recent advances in analysis methods for neuroimaging data such as multi-voxel pattern analysis and related techniques now allow relatively fine-grained “decoding” of brain activity. Decoding involves probabilistic matching, using machine learning, of an observed pattern of brain activation with experimentally established correlations between activity patterns and some kind of functional variable, such as task, behavior, or content. The kind of information provided by functional imaging promises to provide important evidence useful for three goals: Decoding mental content, diagnosis, and prediction. Neuroethical questions arise in all these areas.