Donders Wonders Blog

Changing the emotions of memories

This post is also available in Dutch.

Anxiety disorders have been proven hard to treat, with many people trying all sorts of things. However, there is hope coming from new intervention therapies targeting memory processes.

We all have certain fears, ranging from a fear of heights, to speaking in front of a large audience, to a fear of spiders. Evolutionarily speaking, fear is a protective mechanism which keeps us alert in dangerous situations. However, excessive fear can turn into a burden and become debilitating. This is the case when fear keeps occurring in situations where there is no overt threat present, as is the case in anxiety disorders and posttraumatic stress disorder (PTSD).

Often, this fear is related to an earlier negative experience. However, sometimes fear can be generalized to other situations or the fear experienced in a certain situation can become exaggerated. The emotion of fear has become a problem or ‘maladaptive’ as doctors would call it. But getting rid of these fears is quite difficult, which means there is a lot of work for researchers in the emotional memory field to find good preventive therapies to be able to dampen these inappropriate fear responses. Interestingly, scientists discovered that memories can be changed when they are revisited. This led scientists to consider this memory revisiting processes as a target for intervention therapies for anxiety disorders and opened up a new line of research.

Most of us probably think of memories in terms of stable entities which might fade over time or even be forgotten but apart from that have a fixed content. However, research has shown that when a memory is retrieved, it temporarily enters a labile state: it becomes unstable.  At this moment the memory requires biological processes, such as generation of new proteins, to stabilise again. In a way, you literally refresh your memory when you revisit it. During this phase, called reconsolidation, the memory is vulnerable to interfering influences. This provides an excellent target to work with. Scientists found a drug that can disrupt the proteins needed for refreshing of the memory. If this drug is administered in the right moment, it can actually weaken the fear memory substantially.

Importantly, scientists have argued that this intervention does not erase the original memory. Instead, they suggest that the emotions associated with the memory are updated or that the treatment disentangles the memory from the strong emotions. Multiple studies have been reported, showing promising results: the fear emotion is decreased after just a single intervention session. The effectiveness of this type of intervention, however, is still debated in the scientific community. This is because most human fears are complex, and therefore cannot easily be isolated and targeted.

And to add a whole different perspective, this line of research is not only raising hope that emotional memory disorders might be treated more successfully in the future but is also stimulating philosophical and ethical discussions. If we were to eradicate fear memories in a controlled and guided fashion, are we then not destroying a part of ourselves as experiences and subsequent memories shape our personality? Also, in which cases should we intervene? Where should we draw the line and what kind of memories may not be affected? So, as often happens in life, the solution to one problem poses new challenges to solve.

Written by Eva, edited by Annelies van Nuland.

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