'Unlearning' fear through short interval repeated exposure

[shoe]

According to this study, rats who were conditioned to fear white noise (by having previously associated it with electric shocks) 'unlearned' the fear by being exposed to the stimulus in concentrated bursts (without the previously associated shock), and only when the period of 'rest' between bursts was short. A 6-second period of time between exposure to the stimulus gave the best results in fear extinction. The longer 60-second and 600-second spaced bursts appeared to not have any effect on the fear response in mice.

http://www.apa.org/releases/conditionalfear.html

P.S. I know this is a little old (from 2003), but I just found it, so its news at least to me ;)