Researchers at Uppsala University in Sweden have determined that emotional memories can be effectively erased from the human brain.
"When a person learns something, a lasting long-term 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," explained Thomas Ågren, a doctoral candidate at the Department of Psychology.
"In other words, it can be said that we are not remembering what originally happened, but rather what we remembered the last time we thought about what happened. By disrupting the re-consolidation process that follows upon remembering, we can affect the content of memory."
Ågren's team reached the above-mentioned conclusion by conducting an experiment in which subjects were shown a neutral picture while simultaneously administering an electric shock.
"In this way the picture came to elicit fear in the subjects which meant a fear memory had been formed. In order to activate this fear memory, the picture was then shown without any accompanying shock," he said.
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 reconsolidate the fear memory, the panic they previously associated with the picture dissipated.
Essentially, by disrupting the re-consolidation process, the memory was rendered neutral and no longer incited fear. Additional research, bolstered with the use of an MR-scanner, showed that traces of a specific "fear" memory also disappeared from the part of the brain that normally stores fearful memories, the nuclear group of amygdala in the temporal lobe.
"These findings may be a breakthrough in research on memory and fear. 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," added Ågren.