| In a study that appears in the May 10, 2012, issue of the journal Neuron, scientists from the Florida campus of The Scripps Research Institute have pinpointed a mechanism that is essential for forming memories in the first place and, as it turns out, is equally essential for eliminating them after memories have formed. |
n a study that appears in the May 10, 2012 issue of the journal Neuron, scientists from the Florida campus of The Scripps Research Institute have identified a mechanism that is essential for forming memories in the first place and, as it turns out, is equally important for erasing them after memories have formed.
“This study focuses on the molecular biology of active forgetting,” said Ron Davis, chair of the Scripps Research Department of Neuroscience who led the project. “Until now, the basic thought has been that forgetting is mostly a passive process. Our findings make clear that forgetting is an active process that is probably regulated.”
To better understand the mechanisms for forgetting, Davis and his colleagues studied Drosophila or fruit flies, a key model for studying memory that has been found to be highly applicable to humans. The flies were put in situations where they learned that certain smells were associated with either a positive reinforcement like food or a negative one, such as a mild electric shock. The scientists then observed changes in the flies’ brains as they remembered or forgot the new information.
The results showed that a small subset of dopamine neurons actively regulate the acquisition of memories and the forgetting of these memories after learning, using a pair of dopamine receptors in the brain.
Dopamine is a neurotransmitter that plays an important role in a number of processes including punishment and reward, memory, learning and cognition.
The study suggests that when a new memory is first formed, there also exists an active, dopamine-based forgetting mechanism—ongoing dopamine neuron activity—that begins to erase those memories unless some importance is attached to them, a process known as consolidation that may shield important memories from the dopamine-driven forgetting process.
While Davis was surprised by the mechanisms the study uncovered, he was not surprised that forgetting is an active process. “Biology isn’t designed to do things in a passive way,” he said. “There are active pathways for constructing things, and active ones for degrading things. Why should forgetting be any different?”
The study also brings into a focus a lot of intriguing issues, Davis said—savant syndrome, for example.
“Savants have a high capacity for memory in some specialized areas,” he said. “But maybe it isn’t memory that gives them this capacity, maybe they have a bad forgetting mechanism. This also might be a strategy for developing drugs to promote cognition and memory—what about drugs that inhibit forgetting as cognitive enhancers?”
SOURCE The Scripps Research Institute
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