“‘There's a young student at this university,’ says [British neurologist John] Lorber, ‘who has an IQ of 126, has gained a first-class honors degree in mathematics, and is socially completely normal.  And yet the boy has virtually no brain.’  The student's physician at the university noticed that the youth had a slightly larger than normal head, and so referred him to Lorber, simply out of interest.  ‘When we did a brain scan on him,’ Lorber recalls, ‘we saw that instead of the normal 4.5-centimeter thickness of brain tissue between the ventricles and the cortical surface, there was just a thin layer of mantle measuring a millimeter or so.  His cranium is filled mainly with cerebrospinal fluid.’”  --  Roger Lewin, “Is Your Brain Really Necessary?”  Science 210 (12 December 1980), pp. 1232-1234.