The UW-Madison scientists found that two key regions of the brain - the amygdala and the hippocampus - become activated when a person is anticipating a difficult situation. Scientists think the amygdala is associated with the formation of emotional memories, while the hippocampus helps the brain form long-term recollections, Nitschke says.
The researchers studied the brain activity of 36 healthy volunteers using a technique known as functional magnetic resonance imaging, which produces high-contrast images of human tissue. They began by showing the volunteers two kinds of signals. One was neutral, but the other indicated that some type of gruesome picture was soon to follow, such as explicit photos of bloody, mutilated bodies. Thirty minutes after the researchers had shown dozens of violent images, they quizzed study participants on how well they remembered the pictures they had just seen.
"We found that the more activated the amygdala and hippocampus had been during the anticipation [of the pictures], the more likely it was that a person would remember more of them right away," says Nitschke.
Two weeks after the experiment, scientists met with the study subjects again to measure how well they remembered the same disturbing images. This time, they found that people who best remembered them had shown the greatest amygdala and hippocampus activity during the picture-viewing exercise two weeks before. That suggested that those subjects' brains had already started converting short-term memories of the images into longer-lasting ones.
Mackiewicz says the anticipation of an uncomfortable situation probably kick-starts a kind of "arousal or fear circuitry" in the brain, which in turn helps to reinforce old memories.
"In the future, we could look for ways to dampen that arousal response in patients so that they do not evoke negative memories so easily," she adds.
We need drugs that'll turn on the amygdala and hippocampus so that we can form better memories.
|Share |||Randall Parker, 2006 September 05 11:12 PM Brain Memory|