henry copeland:

Towards an unconscious neural reinforcement intervention for common fears -- ScienceDaily

That is, these researchers can tell if a participant's brain is 'unconsciously' thinking of a snake (which happens every now and then without our awareness), based on images acquired using conventional fMRI (functional magnetic resonance imaging, a measurement available in many hospitals). By giving the participant a small amount of monetary reward whenever this happens, the snake is thus associated with a positive feeling, thereby eventually becomes less frightening and unpleasant.
- www.sciencedaily.com