How does smell influence our brain?
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It’s a rainy morning. I open my window, curl up in my couch and take a sip of the coffee I just finished brewing. It is earthy, musky, creamy... I cannot verbalize all the aromas I sense but the smell sends me back in time to the coffee estate I visited last year in Araku. It equally evokes memories of me and my mother chatting over life. With every sniff of the aroma, the trove of memories starts unleashing...
Smell is the only sense with direct access to memories and emotions
Have you ever asked a person why they like or hate a particular smell? Try. They won’t be able to argue properly. One reason is smell is most often linked to emotions and memories that are formed in early childhood and we are unaware of.
The stimuli from the rest of the 4 senses go through one part of the brain called thalamus (means room in Greek). Imagine it like a security gate..to our consciousness. This strict guard regulates what we are aware and what we are not. For instance, in a room full of banter, you will be able to block the noise if you focus on something else. However, smell can never be avoided because it’s unregulated.
During evolution, humans experienced a profound expansion of the neocortex that re-organized access to memory networks. Vision, hearing and touch all re-routed in the brain as the neocortex expanded, connecting with the hippocampus through an intermediary--association cortex--rather than directly. Our data suggests olfaction did not undergo this re-routing, and instead retained direct access to the hippocampus."
Christina Zelano, Study Lead Investigator and Assistant Professor, Neurology, Northwestern University Feinberg School of Medicine
In other words, smell is the naughty child that escapes the system and roams around freely. It was proven that when we smell not only the olfactory cortex gets activated but parts of the limbic system light up as well like. The main ones are the hippocampus (where memories are formed) and the amygdala (center of emotions).
In some fairs we participated in, we brought some samples so people can smell. The interesting part is that every time people would smell something they liked, we noticed their face lighting up and a wide smile appearing. What better proof of how smell can influence our emotions and mood?
Ice cream will never taste the same again without smell
The loss of smell is called anosmia. It has been proven that smell influences quite a lot the taste of a certain food. It seems when you eat the air goes through your nasal passage and pushes up the flavor all the way to the brain. Before you can even taste the food properly, the brain already has an idea of what you will have in your tummy.
Therefore, sometimes we have the habit of sniffing the food before digging in: this sense is so trained that can tell us whether the food is spoilt or edible. Next time you eat your favorite ice cream pinch your nose and see if besides the sweet taste you can feel any flavor at all.
Lack of smell can lead to depression
If you are being asked what is the sense that you could live without, I am pretty sure you would reply: smell. However, even thought this sense is very subtle and you might think it doesn't affect us much, think twice. This is what research tell us:
"Loss of the sense of smell is underestimated in its impact. It has profound negative effects of quality of life, and many people underestimate that until they experience it. Smell loss is highly correlated with depression and poor quality of life."
Smell can be trained
It seems smell is the only fully developed sense of the fetus while still in the womb. However, once the other sense take over we tend to use less our sense of smell. Not everything is lost though! Dawn Goldworm, co-founder and scent director of the olfactive branding company 12.29, whose main customer is Nike says:
"Your nose is like a muscle in the body that can be strengthened.. by giving it a daily workout, not with weights, but with sniffs."
And this is something aromatherapy does: it trains your sense of smell so you don't lose it!
Wishing you happy sniffing and nice memories,Daniela
Sources:
https://news.harvard.edu/gazette/story/2020/02/how-scent-emotion-and-memory-are-intertwined-and-exploited/https://www.sciencedirect.com/science/article/pii/S1879729610001237
https://www.news-medical.net/news/20210309/Study-reveals-a-neural-basis-for-how-the-brain-enables-odors-to-elicit-memories.aspx