Many of us probably have memories we would like to forget. If that includes you, I have some good news — researchers have discovered two ways we can make our own brains erase memories.
Researchers from the University of Cambridge published a study of these two ways in a paper today, Oct 17, in the journal Neuron.
“This study is the first demonstration of two distinct mechanisms that cause such forgetting: one by shutting down the remembering system, and the other by facilitating the remembering system to occupy awareness with a substitute memory,” study researcher Roland Benoit said in a statement from the journal.
The researchers studied 36 individuals that were asked to remember word pairs like “beach Africa.” They were then told to forget the word pairs using one of two methods: Half the participants were told to just forget the word “Africa” while and the other half were supposed to substitute “Africa” for the word snorkel.
The researchers scanned the participants brains using a functional MRI to measure brain activity while they were actively forgetting. They found different, distinct brain activity for the two different forgetting approaches.
During direct suppression — active forgetting — a brain structure called the dorsolateral prefrontal cortex inhibits activity of the hippocampus, an area involved in memory forming, organizing, and storing.
During thought substitution — thinking “snorkel” instead of “Africa” — the brain’s remembering power (controlled by two spots in the brain that call attention to the thing you are trying to remember) is split between the two words, so it had trouble recalling “Africa” later.
These mechanisms both impair remembering and weaken traces of the unwanted memory. These approaches may help develop new treatments for things like post-traumatic stress disorder. For example a therapist could work with a shaken soldier to dampen the traumatic memories.