This may explain Nadine Dorries…

Found: The Particular Brain Fold That Helps People Distinguish Between Imagination and Reality:

A fold in the front brain called the paracingulate sulcus, or PCS, can apparently help people more accurately remember whether something was imagined or really happened, or which person actually said something. It’s one of the final structural folds to develop before birth, and its size varies greatly in the general population, according to researchers at the University of Cambridge. People with the fold were significantly better at memory tasks than people without the fold, the researchers say.

(Via Popular Science – New Technology, Science News, The Future Now)