India, July 4 -- After weeks spent trying to solve a mathematical problem, French mathematician Henri Poincare was so fed up, he boarded a bus to the scenic town of Coutances. He needed a break. As he was stepping into the bus, a wave of clarity washed over him. In a flash of insight, he knew the answer.

History is full of such tales: Archimedes shouting Eureka; Newton's eye-opening moment involving the apple and gravity; Marie Curie's revelation that the radiation in uranium came from within the atom.

How does this happen?

With advanced brain-imaging scans, researchers can finally see how this extraordinaryorgan behaves just before and after such a realisation; how such aha moments interact with memory and even pleasure; and how they ...