Newly formed emotional memories can be erased from the human brain, according to new research from Uppsala University in Sweden.
“These findings may be a breakthrough in research on memory and fear,” said Thomas Ågren, a doctoral candidate in the Department of Psychology, who led the study.
“Ultimately the new findings may lead to improved treatment methods for the millions of people in the world who suffer from anxiety issues like phobias, post-traumatic stress, and panic attacks.”
Ågren said that when a person learns something, a lasting memory is created with the aid of a process of consolidation, which is based on the formation of proteins.
When we remember something, the memory becomes unstable for a while and is then re-stabilized by another consolidation process, he said.
In other words, we are not remembering what originally happened, but rather what we remembered the last time we thought about what happened, he said. By disrupting the re-consolidation process, we can affect the content of memory.
In the study, the researchers showed subjects a neutral picture and simultaneously administered an electric shock. The picture came to elicit fear in the subjects, which meant a fear memory had been formed, according to the researchers. To activate this fear memory, the picture was then shown without an accompanying shock.
For one experimental group, the re-consolidation process was disrupted with the aid of repeated presentations of the picture. For a control group, the re-consolidation process was allowed to complete before the subjects were shown the same repeated presentations of the picture.
Because the experimental group was not allowed to re-consolidate the fear memory, the fear they previously associated with the picture dissipated. This rendered the memory neutral — and no longer able to incite fear.
At the same time, using a magnetic resonance imaging (MRI) scanner, the researchers were able to show that the traces of that memory also disappeared from the part of the brain that is normally involved in the storage of fearful memories, the nuclear group of amygdala in the temporal lobe.
The study was published in the academic journal Science.
Source: Uppsala University