“Smell is a potent wizard that transports you across thousands of miles and all the years you have lived,” Helen Keller once said. Her words illustrate how the sense of smell, more than any other, can instantly bring back powerful and vivid memories.
Scientists from Northwestern Medicine in Chicago recently provided new information about why that connection is so immediate.
Their study compared connections in the brain between primary sensory areas – including vision, hearing, touch and smell – and the hippocampus, which is known to be the “seat of memory.”
It found that unlike the other senses, olfaction (the sense of smell) has not changed over the course of human history.
While vision, hearing and touch all were re-routed through an intermediary brain area during the process of evolution, olfaction retained a direct connection “like a superhighway, from experiencing a certain smell directly to the hippocampus,” said
Christina Zelano, an assistant professor of neurology at Northwestern’s Feinberg School of Medicine.
With an epidemic of loss of smell now sweeping across the globe due to COVID-19 – and some people losing that critical sense for weeks, months and potentially even longer – understanding the way in which smells affect the brain is more important than ever, Zelano noted.
“While our study doesn’t address COVID smell loss directly, it does speak to an important aspect of why olfaction is important to our lives: smells are a profound part of memory, and odors connect us to especially important memories in our lives,” she said. “There is an urgent need to better understand the olfactory system in order to better understand the reason for COVID-related smell loss, diagnose the severity of the loss and to develop treatments.”