The latest issue (July 21, 2007) of the British medical journal, The Lancet, reports on a startling case of a 44-year-old French man who came to the hospital complaining of weakness in his left leg. In giving his medical history, he noted that he had had a ventricular shunt inserted for a while in his head when he was 9 years old. The shunt had been removed 5 years later when he was 14 years old. The doctors at the hospital decided, therefore, to take a look at the man's adult brain by taking an MRI. They were startled with what they found:
  

(Image taken from Wired Science blog)

The interior of the man's brain consisted mostly of fluid-filled ventricles with highly compressed brain tissue. Somehow, as the man grew up and the brain structure grew increasingly small, the brain was able to compensate. The man's IQ level was in the borderline range (full IQ = 75; verbal IQ = 84; performance IQ = 70), but permitted him to marry, father two children, and maintain a job as a government worker. (Read more at ScienceDirect).

Target article: Feuillet, L., Dufour, H., & Pelletier, J. (2007, July 21). Brain of a white-coloar worker. The Lancet, 370, 262.