There’s interesting research being conducted into ways to modify fear memories. New methods may unlock the potential to reduce post-traumatic stress disorder and other disorders that debilitate many in our society.
Memory re-consolidation occurs when a memory is retrieved and it becomes unstable, thus allowing new information to be incorporated into the memory. When the memory is unstable its re-stabilization process can be blocked or weakened. This process of memory re-consolidation has been shown to help weaken the memory of the negative emotions associated with the fearful memories (Schiller et al., 2010). This does not imply that conscious memory of the event is weakened, rather, it implies that the negative tone of the memory is weakened.
Research in this area has led to using extinction processes that have been shown to weaken fear-associated memories.
Past research has shown extinction training to be successful in the treatment of fear memories, but it has been shown that fear may return under stressful situations. A newer non-invasive method that involves precise timing of extinction training with the conditioned stimuli has been shown to permanently weaken fearful memories (Schiller et al., 2010).
Further research into non-invasive modes of memory re-consolidation — which may serve as a treatment for blocking fearful memories in post-traumatic stress disorder and other anxiety disorders — would be very useful. Unwanted memories are often fearful memories. Fearful memories may be the root cause of some anxiety disorders. Blocking or weakening these memories can lead to decreases in anxiety and other similar disorders. The therapeutic possibilities of this method are far reaching.
Blocking Fear Memories
The re-consolidation hypothesis suggests that memories are reshaped each time they are retrieved (Alberini et al., 2005). This view is in disagreement with the view that memory formation is a one time process, often referred to as consolidation (Mcgaugh, 2000). Research investigating declarative and motor memory suggests information that is presented during the re-consolidation window may lead to the impairment or modifying of older memories (Schiller et al., 2010).
Pharmacological interventions during re-consolidation result in either inhibition or erasing of old memories (Nader et al., 2000). The problem with this line of treatment is the potential toxicity. According to Schiller and colleagues (2010), many of the substances that have been used, in various species, for blocking old memories are toxic to humans.
As mentioned earlier, a non-invasive method proposed by Schiller and colleagues (2010) has been shown to weaken the re-occurrence of fear memories after extinction training. To test their hypothesis in humans, two experiments were designed to investigate whether extinction training during the re-consolidation window (less than 6 hours) could block the return of an extinguished fear. The results showed that the recovery of a fear memory could be blocked if extinction training is conducted during a time window when the fear memory is undergoing re-consolidation.
The study conducted by Schiller and colleagues provided evidence that a non-invasive technique can be used to change fear memories by replacing them with non-fearful memories. Unlike past research that showed the re-occurrence of fearful memories after extinction training, this method seemed to imply that permanent changes in memory can occur.
This line of research is still in its infancy and needs to be replicated to strengthen its value. These results and the results of future research could have important implications for anxiety disorders. This non-invasive treatment represents a safe alternative for memory re-consolidation when compared to pharmacological interventions.
Further investigation into this method will also allow us to learn more about memory, its formation, how it relates to anxiety disorders and how its changes are ubiquitous.
Alberini, CM. (2005). Mechanisms of memory stabilization: are consolidation and reconsolidation similar or distinct processes? Trends Neurosci, 28, 51-56.
Mcgaugh, JL. (2000). Memory- a century of consolidation. Science, 287, 248-251.
Nader, K., Schafe, GE., & Ledoux, JE. (2000). Fear memories require protein synthesis in the amygdala for reconsolidation after retrieval. Nature, 406, 722-726.
Schiller, D., Monfils, MH., Raio, CM., Johnson, DC., Ledoux, JE., & Phelps, EA. (2010). Preventing the fear in humans using reconsolidation update mechanisms. Nature, Vol. 463(7), January.
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