Friday, December 11, 2009

Updating Memories to Prevent the Return of Fear

A new study shows that old fear memories can be “updated” to prevent the return of fear. The discovery is promising for the treatment of post-traumatic stress disorder.

"Our results suggest a non-pharmacological, naturalistic approach to more effectively manage emotional memories," study co-author Elizabeth Phelps, PhD, said in a
press release.

The researchers used mild wrist shocks to condition participants to fear colored squares. A day later, the memory was reactivated.

Participants were re-exposed to the feared squares. This was followed by extinction training. They were repeatedly exposed to the colored squares without shocks.

The fear response was banished only if extinction training followed soon after the fear reactivation. This “reconsolidation window” appears to last for about six hours after the fear is reactivated.

During this time an old memory can be “rewritten.” It can be updated with non-fearful information.

"Timing may have a more important role in the control of fear than previously appreciated," said Phelps. "Our memory reflects our last retrieval of it rather than an exact account of the original event."

The study also found that the technique had a long-lasting effect. Fear responses were no longer expressed when tested one year later.

The AASM reports that recurring
nightmares tend to be most disturbing aspect of PTSD. In these dreams the event may be relived in a way that seems shockingly real.

Earlier this year the Sleep Education Blog
reported that playing the computer game Tetris can reduce unwanted “flashbacks.” Last month the blog noted that imagery rehearsal therapy is helping some people change their nightmares.

Learn more about
sleep and memory.

Image by Stu Mayhew

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