DURHAM, NC -- When French memoirist Marcel Proust dipped a pastry into his tea, the distinctive scent it produced suddenly opened the flood gates of his memory.
In a series of experiments with sleeping mice, researchers at the Duke University Medical Center have shown that the part of the brain that processes scents is indeed a key part of forming long-term memories, especially involving other individuals.
"We can all relate to the experience of walking into a room and smelling something that sparks a vivid, emotional memory about a family member from years or even decades ago," says Stephen Shea, Ph.D., the lead author of the study published in The Journal of Neuroscience. "This research sought to understand that phenomenon on a cellular level."
The researchers examined how strong memories are formed by creating new memories in the minds of mice while under sedation and monitoring their response to a memory-inducing stimulus afterwards, when they were awake.
"Our work is unique because it allows us to examine the cellular make-up of a memory, evaluate how the neurons change when a memory is formed and learn how that memory affects behavior," Shea adds.
The researchers created memories by stimulating the release of noradrenaline, a chemical present in the body during strong emotional events ranging from excitement to fear.
Previous studies have established a link between noradrenaline and the formation of enduring memories, especially during intense social events such as mating and childbirth. In mice and humans, the presence of noradrenaline also creates changes in the odor processing center of the brain, called the olfactory bulb.
"When an animal forms a strong memory about another, it is reliant on odor cues and noradrenaline. Both need to be present at the same time in order for the memory to be formed," Shea says. "Long-term memories created under these conditions often result in a
|Contact: Melissa Schwarting|
Duke University Medical Center