Few memories are as sweet to me as leaning into my mother when I was a child sitting in her comfortable embrace. I remember the way she felt, and her faint rosy scent still lingers in my nose. When I bought my first home, the two enormous rose bushes where I would trim back dead branches and snip brilliant yellow and red blossoms to place on the dining room table, not only connected three generations of rose-loving women in my family but once again, reminded me of mom.
Years later, I recognize that more than just a heavy dose of nostalgia was at play in my springtime garden. Rather, science and basic physiology were at work in my brain, recalling memories with accuracy enviable of cutting-edge computer technology. In fact, the limbic system of my brain, tucked away under my cerebrum, was making split-second connections between a specific fragrance and an associated memory, as well as all of the accompanying “rosy” emotions. Let’s take a closer look at the specific processes taking place as I filled my dining room vase.
THE LIMBIC SYSTEM
Just about dead center of the incredible organ that is our brain, is the not oft considered area known as the limbic region. Major players in the limbic region include the thalamus, hypothalamus (and by extension, the pituitary gland), amygdala, hippocampus, and olfactory bulb. Individually, each of these major components of our cerebral makeup have a myriad of functions, but in concert, they also make up our emotion and memory center, the limbic system. Now let’s look at each component and how they apply to emotions and memories.
The thalamus is like one of those handy-dandy, multi-purpose tools you take camping, but you actually use ALL of the components instead of just the knife and occasionally, the can opener. Known as the sensory relay center (Sight, hearing, touch, and taste, but not smell, are relayed through the thalamus. More about how smell is processed later.), the thalamus also is responsible for motor function, sleep regulation and consciousness. See a breathtaking sunset? That message is received from the retina by the thalamus and processed for a response via emotion or action. Enjoying a particularly glorious Sunday afternoon nap? Thank your thalamus for repressing the relay of sensory information so you can catch some zzzz’s. Want to raise your algebra score? Stimulating the thalamus can improve your cognitive function. (More on how later.)
“Though she be but little, she be fierce” might be how Shakespeare would describe the hypothalamus. Small in size, this tiny region of the brain quickly will let you know if something is amiss. Responsible for releasing hormones, regulating temperature, pleasure and pain response, and overall homeostasis (keeping these elements at a steady baseline), the hypothalamus is one of the most active regions of the brain. The hypothalamus also is closely connected to the pituitary gland (aka. “Master gland”), which plays a crucial function in the endocrine system.
The next time you are watching a scary movie, your significant other gives you a sensual foot massage, or you get cut off in rush-hour traffic, give a little nod to your amygdala. Responsible for these emotions and others, the amygdala also determines which of our memories are stored and where. My fond memories of sitting with mom? Largely, I am able to recall them many years later because of my properly functioning amygdala. But before we go giving the amygdala all of the credit, don’t forget the hippocampus.
Our hippocampus transfers information from short-term to long-term memory. It is widely believed that much of this transference of memories occurs during sleep. I recall being in college and having one of my professors suggesting a 45-minute nap after a study session in order to commit information to our long-term memory. Unfortunately, his suggestion was only partially on target since the short-term to long-term relay hand-off is believed to occur during deep sleep (aka. Stage 3 of Non REM sleep, or NREM), which doesn’t begin until one has been asleep for 35-45 minutes and lasts until REM kicks in, usually around the 90 minute mark. So, the next time you want to remember something for the long run, make sure to catch some winks in the range of 45-90 minutes.
Remember how I told you the thalamus was responsible for receiving and relaying sensory information for all of the senses except for smell? Well, that is because a separate area, the olfactory bulb, has the job of processing our sense of smell before sending the message on to the amygdala. This partnership is crucial to the scent-emotion-memory connection. Let’s break it all down.
Ok. Now, how do all of these components work together to stimulate our emotions and commit them to our memory? Let’s go back to my merry, maternal memories.
Remember the rose connection and how it brought back reminiscences of reading with mom? It turns out the roses may have had less to do with the connection than did Oil of Olay. What? That’s right. Some of my most poignant childhood recollections may just be there because of good timing and mom’s attentiveness to nighttime skincare. Since I was little, my mother has been diligent about her before-bed routine, and she has the youthful skin to show for it well into her 60s now. She removed her makeup, exfoliated her face, gave her cheeks a cool splash to rinse away the oatmeal soap, and then put on a liberal layer of Oil of Olay moisturizer. In my mind’s eye, as I picture that pale pink plastic bottle, the familiar aroma returns to me in vivid remembrance. Rosy and light, and definitively feminine, that smell just says “mom” to me. Shortly after her last dab of the viscous cream, my mother would sit down next to me on my bed and read stories that stay with me to this day. As we enjoyed adventures about girls on wild horses and lands far, far away, I subconsciously drank in the scent of my mother, while a physiological response was taking place deep within my brain. Drifting off to sleep (often before the final “the end”), a perfect storm of limbic region stimulation, scent connection, and perfectly timed Stage 3 NREM cemented the affectionate memories of bedtime stories with mom.
In short, as I lay there before bed, experiencing a peaceful, loving moment, the scent from my mother’s moisturizer rose (pun intended) up into my nose and on to the limbic region of my brain. There, it was received by the olfactory bulb and a message was sent to the amygdala, which already was stimulated through the pleasurable, love emotion I was experiencing. A decision was made to store this memory, and as I fell into deep sleep, the memory had an opportunity to transfer from short-term to long-term memory.
Decades later, a powerful reaction took place in my brain as I tended to my rose bushes. Their aroma, reminiscent of mom’s Oil of Olay moisturizer, triggered a connection to a specific memory and the attendant emotion. Suddenly, feelings of love and missing mom flooded my being.
Why is all of this information important? Because we can use it for our benefit in more ways than one. Let me explain how with these “3 Ways Your Brain is Trying to Talk Some ‘Scents’ into You”.
- Emotional Awareness
In the same way, rosy scents stir up fond feelings for me, other scents can do the same for others or they can do quite the opposite. I remember my grandmother having a visceral repulsion for raw chicken. While she would tolerate it, it definitely was not her favorite protein, and she never would order it in a restaurant. She once explained that as a little girl, her father would have her hold the chickens when he would chop their heads off and process them for meat. Understandably, the whole experience was somewhat traumatic for her, and a strong distaste for the smell of raw chicken lingered with her throughout her life. If we notice a shift in our state, awareness to our surroundings and mental notes of the olfactory cues can help us pinpoint the associated smell. By recognizing negative emotion-scent relationships, we can avoid the scents, manage our responses, or even rewire them. If we want to stimulate positive emotion-scent relationships, simply producing the linked aroma, can trigger the beneficial response. Have you ever walked into an open house and smelled cookies baking? That real estate agent knows the power of stimulating the limbic region of your brain and all the feel-good emotions that go with it because really, who doesn’t get warm and fuzzy feelings of home when they smell freshly baked cookies? Or if we want to rewire our connections, smelling a favorite essential oil such as lemon or lavender during a happy moment can link up the emotion-scent connection in a jiffy.
- Increased Memory and Recall
Studying for an exam or want to keep the axe sharp as you age? Try giving your memories a little nudge with the help of your olfactory bulb. Studies have shown that certain essential oils can have a positive effect on memory, including ameliorating the effects of dementia caused by alzheimer’s disease. At the top of the memory-boosting list are rosemary, peppermint and citrus oils such as lemon. Diffusing these essential oils using an ultrasonic diffuser or even just placing a few drops on some cotton balls nearby for 20 minutes can have your neurons firing on all cylinders.
- Improved Mood
We’ve already reviewed how certain smells can raise our mood in an instant by triggering positive memories, but what if you can’t recall a specific emotion-scent connection or your waistline doesn’t allow for the constant baking of cookies? Never fear, light an all-natural beeswax candle, or once again, pull out your essential oils. Research supports the use of essential oils to reduce anxiety and stress and improve mood. Adding a few drops of lavender to your bath can induce a relaxing mood within minutes. Drop some peppermint and lemon in your diffuser for a blend sure to raise your spirits. Mix up some witch hazel with your favorite essential oils (citrus and frankincense are particularly effective) in a spray bottle, and spritz them in your car before sitting in rush hour traffic, or a few squirts on your pillow before bed for a restful night’s sleep.
Bottom line? Be aware of the scents around you. They may be influencing you more than you know.
Interested in reading some studies on smell, the limbic system, and aromatherapy? Here are a few:
Looking for additional resources on aromatherapy? Try: The Chemistry of Essential Oils Made Simple by David Stewart, PhD, DNM