Actually, it would require a very sophisticated encephalograph, to capture this wispy figment of imagination.

Something along the lines of what Clint Eastwood had to figure out how to use, in the movie "Firefox". But probably much more sophisticated (speaking of fancy imaginations). The Russian fighter jet he was stealing was equipped with a wireless one, which you had to use in order to fly the plane. He had to keep telling himself "Think in Russian you idiot - think in Russian!"