Composite image of the results of a functional magnetic resonance imaging (fMRI) scan overlaid on a model of the brain. fMRI studies show areas of the brain with increased activity during particular tasks. This scan shows the results of a visual sentence completion task, which activated Broca's area in the left frontal (left) lobe and Wernicke's area in the left temporal lobe. Broca's area is linked to speech production, while Wernicke's area is involved in the comprehension of written and spoken language. Areas of the visual cortex at the rear (right) of the brain are also activated.