1. A method for determining whether brain activity of a human subject in response to a stimulus of interest is characteristic of a truthful state or a deceptive state, comprising the steps of: (a) providing a stimulus of interest; (b) measuring brain activity of said subject in response to said stimulus during a period of interest; (c) generating a first brain map of activity prior to or after said period of interest; (d) generating a second brain map of activity during said period of interest; and (e) generating a third brain map of activity representing the difference between said first brain map and said second brain map; and (f) determining whether the brain activity in at least one brain region selected from the group consisting of right orbitofrontal cortex and right anterior cingulate cortex of said third brain map of activity exceeds a predetermined control level of activity, wherein the brain activity in said at least one brain region selected from the group consisting of the right orbitofrontal cortex and the right anterior cingulate cortex of said third brain map of activity is characteristic of said truthful state or said deceptive state if it exceeds said predetermined control level of activity.