DURHAM, N.C., Oct. 17 (UPI) -- U.S. researchers say the reason a baking apple pie can bring back memories is because the part of the brain involved with scents also deals with memories.
"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," lead author Stephen Shea, of the Duke University Medical Center in Durham, N.C., says in a statement. "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 afterward, when they were awake. 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.
The study, published in The Journal of Neuroscience, found an approximate 40 percent reduction in neuron activation after triggering the noradrenaline release -- suggesting that a memory of the odor had been formed. A day later, after the mouse was awake, the team observed changes in behavior in response to the scents, showing that they remembered the smells from when they were asleep, the study says.