Functional magnetic resonance imaging is a relatively new, noninvasive technique which has a maximum spatial resolution in the range of 1 mm and temporal resolution of 0.1-1 s. The technique is not quantitative but results have proved reliable and reproducible and studies are quick to perform. Already substantial progress has been made in mapping the visual, sensorimotor and auditory systems and promising results achieved in the study of higher cognitive function such as memory and linguistic processing. Clinical applications have been made in epilepsy surgery, the study of schizophrenia, genetic abnormality and cerebral injury.