Scents of Smell

Next up in the senses-series, we have “smell,” which is very closely related to taste, and also a powerful stimulator of memory.

You may be thinking I’ve used the wrong word in the title of this post, but did I? 🤔

I’ve done quite a bit of pondering about our senses lately and find myself in awe over how the human body was designed, but I’ve never really understood how the olfactory system works and anatomy classes were a very long time ago, so I asked ChatGPT three questions.

There is a lot to get through here, but these are things I’ve been curious about and the answers are fascinating to me. I’ll follow with my own human perspective on it and how we can use “scents of smell” to bring us into a state of mindfulness.

First question: Tell me about the human sense of smell. How does it work?

“The human sense of smell, or olfaction, is a fascinating and complex process that allows us to detect and identify scents in the environment. Here’s how it works:

1. Detection of Odors

• Molecules in the air: Odors are made up of volatile molecules that are released by substances around us, like food, flowers, or chemicals. These molecules travel through the air and enter the nose when we breathe.

2. The Nose and Olfactory Receptors

• Nasal cavity: When you inhale, air containing odor molecules travels through your nostrils and into the nasal cavity. Inside the nasal cavity, there is a specialized area called the olfactory epithelium, which is responsible for detecting odors.
• Olfactory receptors: The olfactory epithelium contains millions of olfactory receptor cells (nerve cells). These receptor cells have tiny hair-like structures called cilia that are covered in proteins specifically designed to bind to certain odor molecules. When an odor molecule binds to a receptor, it triggers a chemical signal.

3. Signal Transmission

• Once the odor molecules bind to the receptors, they activate these receptor cells, which send electrical signals to the brain. This happens through the olfactory nerve, which is the nerve responsible for transmitting smell information.

4. Processing in the Brain

• The olfactory nerve sends the signals to the olfactory bulb, a structure at the base of the brain that processes smells. From there, the information is relayed to different parts of the brain, particularly the olfactory cortex, which is involved in identifying and interpreting smells.
• Interestingly, the olfactory bulb is directly connected to the limbic system, which is the part of the brain associated with emotions and memories. This is why smells can often trigger vivid memories or strong emotional responses.

5. Identification and Interpretation

• The brain interprets the signals from the olfactory receptors and helps you recognize and identify specific scents, like the smell of freshly baked bread, perfume, or a flower. The brain can also determine the intensity of a smell and whether it’s pleasant or unpleasant based on past experiences and learned associations.

Additional Facts:

• Sensitivity: The human sense of smell is highly sensitive. We can detect thousands of different smells, and it's estimated that humans can distinguish between around 1 trillion different odorants.
• Adaptation: The sense of smell is adaptive. This means that over time, if you’re exposed to a constant odor, your sensitivity to that odor can decrease. This is known as olfactory adaptation.
• Unique to Each Person: Like fingerprints, everyone’s sense of smell is unique. The number and types of olfactory receptors vary between individuals, which is why some people can identify certain smells more easily than others.

Smell is not just important for identifying scents; it also plays a key role in taste. Together, these senses contribute to the overall experience of flavor when eating or drinking.

Isn’t it amazing how the brain works in harmony with our senses to create such a rich experience of the world?”

Second Question: How does smell tie in with our sense of taste?

Smell and taste are closely linked, working together to create the full experience of flavor. In fact, most of what we perceive as "taste" is actually related to our sense of smell. Here's how the two senses are connected:

1. The Basics of Taste

Taste itself is limited to five basic sensations:

• Sweet
• Sour
• Salty
• Bitter
• Umami (savory)

These tastes are detected by taste buds on the tongue and the roof of the mouth, which contain specialized cells that respond to chemicals in food. However, these taste sensations are just the foundation of what we perceive as flavor.

2. The Role of Smell in Flavor

When we eat or drink, molecules from the food travel up the back of the throat to the olfactory receptors in the nose. This is called retronasal olfaction (as opposed to orthonasal olfaction, which is when we smell something by sniffing it directly through our nostrils).

• Smell adds complexity: The aromas of food or drink that travel to the nose are what give us the complex, nuanced flavors of what we’re consuming. For example, the fruity aroma of a strawberry, the earthy scent of coffee, or the spicy fragrance of a curry all add layers of perception that make the experience more vivid.
• Without smell, flavor is diminished: When you have a cold and your nose is blocked, you often notice that food loses much of its flavor. You can still taste the basic elements (sweet, sour, salty, etc.), but the richness and variety of the flavor are greatly reduced. This happens because, without the input from the olfactory system, your brain doesn’t receive the full sensory information needed to interpret the full "flavor" of the food.

3. How Smell and Taste Work Together in the Brain

• The signals from your taste buds and olfactory receptors are sent to different parts of the brain, but they converge in the gustatory cortex and olfactory cortex, allowing the brain to integrate both signals into a unified perception of flavor.
• The brain is very skilled at combining taste (which is more basic) and smell (which adds complexity), and it uses this integrated information to create the rich, detailed sensation of flavor.

4. The Importance of Aroma

• Aroma is crucial: While the five basic tastes can help us identify things like sweetness in fruit or saltiness in chips, the unique characteristics of each food are mostly carried by its aroma. Think of how an orange smells, and then think of how it tastes. The aroma influences the perception of sweetness, tartness, and the overall flavor profile.
• Smell helps detect flavor nuances: Without smell, we wouldn’t be able to distinguish between complex flavors such as the difference between vanilla and almond or the subtle notes of a well-aged wine. The subtlety of flavor is largely a result of the complex smells we perceive when eating.

5. Examples of the Connection

• Food experience: Have you ever had a piece of chocolate or a strawberry, and while you’re eating it, you notice the wonderful smell? That’s your brain combining the basic sweet taste with the smell to create a richer experience.
• Tasting wine: Wine connoisseurs often talk about "the bouquet" or "nose" of the wine. They can detect notes of fruit, herbs, or even spices not just from the taste but from the aromas that travel up into the nose as they sip the wine.

6. Impact of Smell Loss

• Anosmia is the loss of the sense of smell, which can significantly impair the experience of food. People with anosmia may still be able to taste the five basic flavors but lose the complexity and pleasure of flavors that come from the aroma. This is why a person with anosmia might not find eating as enjoyable.

In summary, while taste detects the basic qualities of food, smell enriches that experience, providing the nuances and details that make eating an enjoyable, multi-sensory event. The combination of both senses leads to what we ultimately perceive as flavor, and without one, the other would be much less vibrant!”

*I’ll do a separate blog post on sense of taste in the near future.

 

Third question: Tell me about the relation between smell and memory

“The relationship between smell and memory is incredibly powerful and intriguing, largely because of the way our brain processes smells. Here’s a breakdown of how the two are connected:

1. The Brain Pathways: A Unique Connection

The key to the connection between smell and memory lies in the brain's anatomy. Smell (olfaction) is processed in the brain through the olfactory system, and it has a direct link to the limbic system, which is involved in emotions and memory. Here’s how this connection works:

• Olfactory bulb: When you inhale an odor, the molecules interact with the olfactory receptors in your nose, and the information is sent to the olfactory bulb, which is the first brain structure to process the smell.
• Limbic system: From the olfactory bulb, the information is transmitted to the limbic system, which includes the hippocampus (critical for memory) and the amygdala (important for emotions). These areas are directly involved in the processing of emotions and the storage and retrieval of memories.
• This unique connection between the olfactory system and areas of the brain associated with emotion and memory helps explain why smells can evoke vivid memories or strong emotional responses.

2. Why Smells Trigger Memories

• Emotional and memory-rich experiences: Because of the limbic system's role in both emotions and memory, smells can trigger emotionally charged memories. For instance, the scent of a particular perfume may remind you of a loved one, or the smell of a specific dish could bring back memories of family gatherings. This is because the brain links these smells with personal experiences that are emotionally significant.
• Proustian effect: The phenomenon where a scent brings back a specific memory is often referred to as the Proustian effect, named after the writer Marcel Proust. In his famous novel In Search of Lost Time, Proust describes how the smell of a madeleine (a small cake) dipped in tea triggers a flood of memories from his childhood. This type of memory retrieval is powerful because the emotional component associated with the smell amplifies the recall of the specific event or time.

3. Smell as a Trigger for Long-Term Memories

• Long-lasting impressions: Smell can sometimes serve as a powerful long-term memory trigger because it is processed in areas of the brain involved in storing and recalling deep memories. Unlike vision or hearing, which are processed in different regions, smells have a direct route to these emotional and memory centers in the brain, making them particularly potent at triggering memories, even from many years ago.
• Smell and nostalgia: Often, a scent can immediately transport us back to a specific time or place. This is why certain smells, like fresh-cut grass, a specific perfume, or the smell of a childhood home, can evoke strong feelings of nostalgia or longing for the past.

4. The Science Behind Smell and Memory

• Strong emotional component: The connection between smell and emotion is evolutionary. Early humans may have needed to associate certain smells with danger or safety, like the scent of fire or the presence of food. Over time, this sensory link became tied to emotional memories, which is why smells are so effective at evoking emotions.
• Personal and unique associations: Smell is a very personal sense, as it varies from person to person. The same scent can trigger different memories or emotional responses depending on individual experiences. For example, a certain smell might remind one person of a vacation, while another might associate it with a traumatic event.

5. Smell and Alzheimer's or Dementia

• Memory loss: In people with conditions like Alzheimer’s disease or other forms of dementia, the sense of smell is often one of the first to decline. Research has shown that the olfactory system is one of the first areas affected by neurodegenerative diseases, which may explain why people with dementia often lose their ability to recognize familiar smells.
• Therapeutic potential: Interestingly, the use of familiar smells has been explored in therapeutic settings to help people with memory loss. Familiar scents may help trigger lost memories or bring comfort to those with dementia, offering a potential tool to help with memory recall and emotional well-being.

6. Why Smell is So Powerful in Memory Recall

• Direct brain route: Smell is one of the few senses that has a direct connection to the limbic system, which is where memories are processed and emotions are triggered. In comparison, other senses like sight and hearing must pass through the thalamus before reaching the areas of the brain that process emotion and memory.
• Rapid processing: Smell is processed almost instantly, which is why we often have immediate emotional or memory responses when encountering a familiar scent. This speed gives it an edge in triggering memories, often without conscious effort.

7. Practical Examples

• The smell of rain (petrichor): For many people, the smell of rain on dry earth, known as petrichor, evokes memories of childhood, outdoor adventures, or simply the feeling of peace and nostalgia. This can be linked to happy, carefree times, evoking a sense of calm or happiness.
• A familiar cooking aroma: The smell of a family recipe or a favorite dish can trigger memories of home or holidays, often bringing a deep emotional connection to family or heritage.

In summary, smell and memory are deeply intertwined because of how the brain processes and links scents with emotions and personal experiences. The powerful connection between the olfactory system and the limbic system makes smells potent triggers for vivid memories, often bringing a flood of emotions and sensations associated with past events.”

How I plan to use this information

I had a feeling about the effects of smell on memory, I know I’ve gotten emotional when picking up certain scents. When my mom died, I kept a few of her things – including a couple of different perfumes. One of them was White Shoulders by Design House of Evyan and the other was one she kept of my grandmother’s who has also passed. This one is called Shalimar by Guerlain.

I’ve got them in my bathroom cabinet and sometimes I’ll just go in there, pull one out and pop the lid and I’m immediately taken back into time. Especially the White shoulders. That one takes me back to childhood, laying in my mom’s lap while she plays with my hair and lightly scratches my back. I love those memories and I can literally feel them in my physical body as well as my soul. THIS is mindfulness in action!

There is a weird phenomenon that happens to me in the morning, I can smell coffee brewing before I ever go to make it. Strange right? There have been times I’ve gone without coffee for one reason or another and on those days, I’ll smell it for hours if I’m at home. I happen to work as a Quality Assurance Specialist for a company that produces cold-brew coffee systems for home and commercial use and we’ve also got an on-premise roastery and tasting room, so now coffee is even more a part of my life.

The smell of rain. Not just while it’s raining, but before it even starts. It’s called “petrichor” and for some reason it fills me with a sense of calm.

Here is some of the science behind it:

I can’t think of a better time to chill and meditate than when we are enveloped in both petrichor and the sound of rain combined. I lean into it and soak up as much as I can (figuratively 😊).

Another big one for people in my generation that we vividly remember from childhood – Coppertone! Boy oh boy, the amount of time I spent in the sun throughout the years that I shouldn’t have. I’ve had to suffer some consequences (skin cancers) due to all that – but dammit, I still love that smell and no one can take that away from me! And yes, we very recently found an ingredient in Coppertone known to be carcinogenic (Benzene as recent as 2021? Come on now! 🤦‍♀️), they have made efforts to update their products to be less toxic and more reef safe.

A few more scents tied to my memories:

·         Patchouli = Head shops & hippies.

·         Cooking Thanksgiving = Beautiful memories with my family.

·         Pine trees = Hikes & camping trips I’ve been on.

·         My slow-roasted corned beef = All the St. Patrick’s Days I’ve cooked for my family.

I’m sure I could come up with quite a few more, but I need to move onto other tasks now. Maybe try thinking of some of your own (good) memories and lean into them. If you have a fragrance on hand that can help trigger those memories, all the better. Immerse yourself in this practice and really feel it. THIS is mindfulness!