A research team from New York University and the University of Texas at Austin demonstrated that timing is critical in extinguishing a fear response – and this has groundbreaking potential for the treatment of phobias, anxiety disorders and posttraumatic stress.  Evidently, there’s a brief window of opportunity for rewriting painful emotional memories immediately after re-activating them, when the imprinted memory becomes labile and open to change.

Simple fear was created in 65 subjects by giving them a mild electrical shock on the wrist one third of the time when shown a colored square appear on a computer screen (Earlier research in conditioned learning shows that this is the frequency of ‘punishment’ that creates a lasting association).

The next day, the sight of the square drew an immediate fear response, as measured by sensors on the skin. Participants were then given “extinction” training, to override the painful memories, by repeatedly showing them the colored square without the accompanying shock.

But first they were divided into three conditions, with different timings and methods. In the first group, given the extinction training just 10 minutes after being reminded of the painful memory, subjects no longer reacted emotionally to the sight of the colored square — their fear was extinguished, with no trace of it a full year later. 

However, participants in the second group, who received extinction training six hours after being reminded of the shocks, and those in the third group, who were not first shown the square to remind them of the fearful memory, still showed a physiological dread at the sight of the square.

This is a very important finding, pinpointing this period of brain flexibility just after a fear response, and no doubt a lot of targeted techniques being used now for anxiety, phobias and posttraumatic stress will no doubt  be experimenting with first reactivating the fear before moving into introducing the intervention.  Kudos to this team for these exciting findings.

Citation: Schiller D, Monfils MH, Raio CM, Johnson DC, Ledoux JE, Phelps EA. Preventing the return of fear in humans using reconsolidation update mechanisms. Nature advance online publication 9 December 2009.  [email protected]