A man with an unusually tiny brain manages to live an entirely normal life despite his condition, which was caused by a fluid build-up in his skull.Scans of the 44-year-old man's brain showed that a huge fluid-filled chamber called a ventricle took up most of the room in his skull, leaving little more than a thin sheet of actual brain tissue.Intelligence tests showed the man had an IQ of 75, below the average score of 100 but not considered mentally retarded or disabled."The whole brain was reduced – frontal, parietal, temporal and occipital lobes – on both left and right sides. These regions control motion, sensibility, language, vision, audition, and emotional and cognitive functions," Feuillet told New Scientist.