A new discovery in repressed memories may help treat addiction and other problems, writes Daniel Tencer
A team of American researchers has identified the areas of the human brain responsible for memory suppression, a finding that could be used to better understand psychological problems such as addiction and trauma.
The authors of the study, Dr. Michael Anderson of the University of Oregon and Dr. John Gabrieli of Stanford University, say this is the first time anyone has shown a neurobiological basis for memory repression.
According to Dr. Gabrieli, the findings could have a significant impact on addiction treatment. “One of the big problems with addiction is craving,” he says.
“Certain situations can create cravings, so that suggests there’s a dredging up of memories happening there that make you feel more susceptible to doing things you may not want to do.”
Dr. Gabrieli speculates the discovery could help treat addicts’ cravings, as many cravings are triggered by memory. The research could also help individuals suffering from post-traumatic stress disorder.
“Its application here is speculative, but many (people who have gone through) horrible war experiences … are able to suppress it,” says Dr. Gabrieli. “So we imagine the same kind of mechanism, whether it’s pharmacological or behavioural, would be useful for patients who can’t overcome the terrible experience they had.”
The findings settle at least part of a century-old debate on the topic of repressed memories: Sigmund Freud postulated that people who experienced trauma in childhood were able to block their memory effectively enough to not recall the event in adulthood.
“This does not end the debate about whether repressed-memory syndrome is a real phenomenon, but it does end the debate over whether there is a mechanism for repressing memories,” says Dr. Anderson.
Repressed-memory syndrome is a highly controversial psychological phenomenon in which people claim to recover lost memories after years or decades. In these cases, the repression tends to be involuntary, whereas in the recent experiments, subjects were consciously attempting to repress memories.
But whether the memory suppression is voluntary or involuntary, Dr. Gabrieli says we now know that “retrieving the memory becomes very difficult.
“The suppression of thinking about something ultimately makes it unavailable to you on any basis,” he says.
Participants in the study were asked to memorize 36 sets of word pairs. They were shown the first words of the pairs and asked to recall its partner. Then they were shown the first words and asked not to recall its partner. Using an MRI machine, the researchers were able to track the brain activity of the participants.
The researchers discovered that unwanted memories can be suppressed with brain areas similar to those used when individuals try to stop physical actions. Simply put, the same parts of the human brain that stop an arm from waving can also be used to stop a memory from being retrieved.
“There is a lot of evidence that people have to suppress bad experiences just to move forward; you know, when they think about everything from terrorist threats to mad cow,” says Dr. Gabrieli.
“So, evolutionarily, the capacity to repress disturbing memories is there so that you can move forward.”
The Ottawa Citizen
Friday, January 9, 2004
