You are looking at the surface of a living brain belonging to an epileptic patient. The photograph is taken during an operation, just before an intracranial electrode recording procedure for epilepsy takes place, in which electrical activity is measured from the exposed surface of the brain.
The image displays the pink ‘grey’ matter (which is grey in dead), the red arteries that supply the brain with nutrient and oxygen and the purple veins that return deoxygenated blood to the heart.
Source: Welcome Images
Photo credit: Robert Ludlow, UCL Institute of Neurology, London