Welcome to brain stuff, a production of I Heart Radio, Hey, brain stuff, Lauren Volga bam here. Close your eyes if it's safe to do so, and conjure up the following smells.
Burst of citrus while peeling a juicy orange, the green piney scent of a fresh cut Christmas tree, or a warm waft of perfume from a blooming lilac bush is the very idea relaxing Stretching back millennia, ancient cultures like those in China, India, and Egypt recognized that certain aromas are deeply soothing, and folk healers have long prescribed sent it essential oils for treating stress induced conditions like anxiety, insomnia,
and headaches. But science is still trying to figure out exactly how and why these potent aromas produce calming physiological responses. Our sense of smell is triggered when fragrance molecules attached to special cilia covered olfactory nerve receptors in our nasal cavity.
Those receptors then send electrical signals directly to the olfactory cortex of the brain, which in turn talks to the memory and emotion centers of the brain like the hippocampus, amygdala, and frontal cortex, and a study published in the journal Frontiers and Behavioral Neuroscience strengthens the theory that some smells can act like nature's own anti anxiety medication, tweaking our brain chemistry in ways that mimic the effects of prescription
drugs like valium and diazepam. In a series of experiments, Japanese researchers ran nice through mazes and other rodent stress tests while exposing them to an aroma called Lanella wall. It's the compound that gives lavender its sweet floral scent.
From previous studies, they suspected the Lunella wall would lower anxiety levels in the mice, which it did, But the scientists also wanted to test a hypothesis that lavender's calming effect went straight from the mouse's nose to its neurons, so they included mice in the study that were anasmic, meaning they had no sense of smell. Those mice showed no effect from exposure to Linnell wall, approving that the
olfactory system was definitely the delivery mechanism. Next, the researchers wanted to figure out whether Lennella wall was targeting the same receptors in the brain as some of the most common prescription anti anxiety medications. Drugs like valium, xanex, klonopin, and diazepam, are all members of the same drug family called benzo diazepines. One of the causes of clinical anxiety is overactive neuronal activity in the brain, and benzo diazepines
can inhibit or calm down neuronal activity. They do this by binding to particular sites on rons called gammamno buttyrric acid or GABBA receptors. The Japanese researchers made a strong case that the smell of lavender acts on those very same GABA receptors. They did this by treating some of the mice with a drug that blocks GABA receptors, and when those treated mice sniffed the lunel wall, they didn't
exhibit any calming effects. Lavender isn't the only aroma that's been linked to the same neuron receptors as potent anti anxiety drugs, though. A few years ago, German researchers tested hundreds of fragrances on GABA receptors in rodents and humans, and the big winner was jasmine, which delivered a gabba effect as powerful as sleeping pills and sedatives. Lavender and jasmine are the first ancient relaxation remedies to be tested like this, but several others may share a similar nosed
brain mechanism, according to that Japanese study. Other compounds that have shown promising anti anxiety effects in mice and men include lemoning, one of the aroma compounds of citrus peels, and pining, one of the aroma compounds of pine trees. Aromas aren't universally relaxing, though, Since smells share such a close neurological connection to memories and emotions, their physiological effects
can also be altered by our personal experiences. Like Pavlov's dogs, our brains can be conditioned to love or hate certain smells depending on our associations with them. For example, if you had a negative experience at a job or as a child scrubbing messes out with lemon scented cleanser, you might not find the odor all that soothing. A Research has shown that the olfactory system has the strongest direct line to the hippocampus and the amygdala, which are the
memory and emotional centers of the brain. This is why sent memories can evoke such powerful feelings of nostalgia. A smell can carry us back to a specific time and place in ways that conscious thinking and remembering just can't. That might explain why we find the smell of baby powder so soothing. It summons feelings of security and love from deep in our earliest memories. But even that smell
appears to have cultural variations. Americans associate the new baby smell with vanilla and powdery sense, while the French associate babies with the scent of orange blossoms. For some people, the smell of sunscreen is a stress reliever since it reminds them of care free summer days at the beach, and so if work is stressing you out, consider stowing a squeeze bottle of sp of fifty in your desk.
Today's episode is based on the article what makes a sense soothing on houseuff works dot com, written by Dave Rouse. Brain stuff It's production offi Heart Radio in partnership with how Stuff Works to dot Com was produced by Tyler Playing and Ramsay Young. Four more podcasts from my heart Radio visit the i heart Radio app. Apple Podcasts or wherever you listen to your favorite shows.