The correct answer is he's screwed because with enough training in a mock scanner, the fMRI is sure to work.
The FBI kidnapped Mike and put him in an fMRI machine to track whether he was lying or not. FBI detects lies from the flow of blood. when he is lying, his brain put more efforts and more flow of blood.
fMRI detects lies according to brain activation patterns. Its brain activation patterns shoed different from the person who is innocent.
The flow of blood in activated areas helps in tracking lies using an fMRI machine. So, during the lie detection areas highlighted if a person lies.