Functional Magnetic Resonance Imaging (fMRI) is a relatively new tool that can be used to demonstrate areas of neuronal activation within the human brain. This technique does not expose the subject to ionising radiation, uses endogenous contrast mechanisms and has good temporal and spatial resolution. The technique can be applied to the study of basic neurophysiological processes as well as providing clinically useful information about areas of important brain function. This paper introduces the technique of fMRI, explaining the origin of detectable signal changes in terms of the physiological alterations that occur with neuronal activation. An illustrative example of a motor activation study is described.

Keywords: brain activation, functional magnetic resonance imaging (fMRI)