Schizophrenia verbal task. Coloured Positron Emission Tomography (PET) brain scans of a schizo- phrenic (at bottom) versus normal patient (at top) speaking. The external brain is seen, with left side on the left. Areas highlighted in red/yellow are active during a task when patient's were asked to generate words. The normal brain (top) shows much activity in prefrontal and motor areas, less in parietal area on the left side. In the schizo- phrenic brain, these areas are active, with the added area of the temporal gyrus (lower centre of brain) not seen in normal subjects. Schizophrenia produces deluded thoughts and depression.