Regions of smells, memories, and emotions are very much intertwined in the brain that your sense of smell which is wired to your brain is unique among your senses.
A scent is a chemical particle that floats in through the nose and into the brain's olfactory bulbs, where the sensation is first processed into a form that's readable by the brain. Brain cells then carry that information to a tiny area of the brain called the amygdala, where emotions are processed, and then to the adjoining hippocampus, where learning and memory formation take place.
Scents are the only sensations that travel such a direct path to the emotional and memory centers of the brain. All other senses first travel to a brain region called the thalamus, which acts like a "switchboard," relaying information about the things we see, hear or feel to the rest of the brain, said John McGann, an associate professor in the psychology department of Rutgers University in New Jersey. But scents bypass the thalamus and reach the amygdala and the hippocampus in a "synapse or two," he said.
That results in an intimate connection between emotions,
memories and scents. This is why memories triggered by scents as opposed to other senses are "experienced as more emotional and more evocative," said Rachel Herz, an adjunct assistant professor of psychiatry and human behavior at Brown University in Rhode Island. A familiar but long-forgotten scent can even bring people to tears, she added.