It turns out that our memories are extremely mouldable. In fact – contrary to the long-accepted view that once a memory is captured and stored in our brain’s neural circuits, it can be retrieved but not rewritten – our memories are actually recast and revised every time we recall them. This is according to Daniela Schiller, a Mount Sinai School of Medicine neuroscientist who is harnessing this new understanding of memory – that it is in “an unstable state, rewritten and remodeled every time it is retrieved “ – with a view to updating memories, particularly in the case of painful ones, so that a negative experience is remoulded into one with a positive context.
Schiller’s specialty is in the connection between memory and fear. While evolutionarily speaking, fear memories are an important survival mechanism using cues in the environment to prompt certain responses, they can also be detrimental to our daily life when in extreme cases, emotional memories become traumatic and the ability to inhibit fear when it is no longer needed is not there. Schiller, out of her lab at Mount Sinai Medical School along with other researchers spearheading memory research, has gathered data to put forward the case that we can alter the emotional impact of a memory by adding new information to it or recalling it in a different context – essentially, repairing bad memories and “reconsolidating” them.
The suggestion from her research with her NYU colleagues, underscored in a landmark 2010 paper in Nature, is that if mitigating information about a traumatic event is introduced within a very small window of opportunity after its recall, the emotional experience of the memory can be “rewritten” – the memory can be “reconsolidated” without fear – “When you affect the emotional memory, you don’t affect the content,” explains Schiller. “You still remember perfectly. You just don’t have the emotional memory.”
Her interest in the nature of human memory was piqued in the sixth grade when on the annual Holocaust Memorial Day in Israel, for a school project she asked her father about his memories as a Holocaust survivor and was met with silence every time. The whole of Israel comes to a stop on this day for exactly two minutes with an eruption of sirens that can be heard from the Mediterranean to the Dead Sea and it was always the same – as if the memorial day and the blaring sirens, at least for her father, did not exist.
Her curiosity about what had happened to him, what he was concealing and why, and how people come to cope in this way became the foundation, in large part, of her career focus on how emotional memories are formed in the brain. “I want to disentangle painful emotion from the memory it is associated with,” Schiller explains. “Then somebody could recall a terrible trauma, like those my father obviously endured, without the terror that makes it so disabling. You would still have the memory, but not the overwhelming fear attached to it.”
Schiller’s and her colleagues’ findings challenge 100 years of neuroscience and turn our understanding of the permanence of memory on its head, with the potential behavioural and clinical implications of memory reconsolidation for new treatment down the line being immense.