Speaker 1: Welcome to brain stuff, a production of I Heart Radio, Hey,
Speaker 1: brain stuff, Lauren Volga bam here. Close your eyes if
Speaker 1: it's safe to do so, and conjure up the following smells.
Speaker 1: Burst of citrus while peeling a juicy orange, the green
Speaker 1: piney scent of a fresh cut Christmas tree, or a
Speaker 1: warm waft of perfume from a blooming lilac bush is
Speaker 1: the very idea relaxing Stretching back millennia, ancient cultures like
Speaker 1: those in China, India, and Egypt recognized that certain aromas
Speaker 1: are deeply soothing, and folk healers have long prescribed sent
Speaker 1: it essential oils for treating stress induced conditions like anxiety, insomnia,
Speaker 1: and headaches. But science is still trying to figure out
Speaker 1: exactly how and why these potent aromas produce calming physiological responses.
Speaker 1: Our sense of smell is triggered when fragrance molecules attached
Speaker 1: to special cilia covered olfactory nerve receptors in our nasal cavity.
Speaker 1: Those receptors then send electrical signals directly to the olfactory
Speaker 1: cortex of the brain, which in turn talks to the
Speaker 1: memory and emotion centers of the brain like the hippocampus, amygdala,
Speaker 1: and frontal cortex, and a study published in the journal
Speaker 1: Frontiers and Behavioral Neuroscience strengthens the theory that some smells
Speaker 1: can act like nature's own anti anxiety medication, tweaking our
Speaker 1: brain chemistry in ways that mimic the effects of prescription
Speaker 1: drugs like valium and diazepam. In a series of experiments,
Speaker 1: Japanese researchers ran nice through mazes and other rodent stress
Speaker 1: tests while exposing them to an aroma called Lanella wall.
Speaker 1: It's the compound that gives lavender its sweet floral scent.
Speaker 1: From previous studies, they suspected the Lunella wall would lower
Speaker 1: anxiety levels in the mice, which it did, But the
Speaker 1: scientists also wanted to test a hypothesis that lavender's calming
Speaker 1: effect went straight from the mouse's nose to its neurons,
Speaker 1: so they included mice in the study that were anasmic,
Speaker 1: meaning they had no sense of smell. Those mice showed
Speaker 1: no effect from exposure to Linnell wall, approving that the
Speaker 1: olfactory system was definitely the delivery mechanism. Next, the researchers
Speaker 1: wanted to figure out whether Lennella wall was targeting the
Speaker 1: same receptors in the brain as some of the most
Speaker 1: common prescription anti anxiety medications. Drugs like valium, xanex, klonopin,
Speaker 1: and diazepam, are all members of the same drug family
Speaker 1: called benzo diazepines. One of the causes of clinical anxiety
Speaker 1: is overactive neuronal activity in the brain, and benzo diazepines
Speaker 1: can inhibit or calm down neuronal activity. They do this
Speaker 1: by binding to particular sites on rons called gammamno buttyrric
Speaker 1: acid or GABBA receptors. The Japanese researchers made a strong
Speaker 1: case that the smell of lavender acts on those very
Speaker 1: same GABA receptors. They did this by treating some of
Speaker 1: the mice with a drug that blocks GABA receptors, and
Speaker 1: when those treated mice sniffed the lunel wall, they didn't
Speaker 1: exhibit any calming effects. Lavender isn't the only aroma that's
Speaker 1: been linked to the same neuron receptors as potent anti
Speaker 1: anxiety drugs, though. A few years ago, German researchers tested
Speaker 1: hundreds of fragrances on GABA receptors in rodents and humans,
Speaker 1: and the big winner was jasmine, which delivered a gabba
Speaker 1: effect as powerful as sleeping pills and sedatives. Lavender and
Speaker 1: jasmine are the first ancient relaxation remedies to be tested
Speaker 1: like this, but several others may share a similar nosed
Speaker 1: brain mechanism, according to that Japanese study. Other compounds that
Speaker 1: have shown promising anti anxiety effects in mice and men
Speaker 1: include lemoning, one of the aroma compounds of citrus peels,
Speaker 1: and pining, one of the aroma compounds of pine trees.
Speaker 1: Aromas aren't universally relaxing, though, Since smells share such a
Speaker 1: close neurological connection to memories and emotions, their physiological effects
Speaker 1: can also be altered by our personal experiences. Like Pavlov's dogs,
Speaker 1: our brains can be conditioned to love or hate certain
Speaker 1: smells depending on our associations with them. For example, if
Speaker 1: you had a negative experience at a job or as
Speaker 1: a child scrubbing messes out with lemon scented cleanser, you
Speaker 1: might not find the odor all that soothing. A Research
Speaker 1: has shown that the olfactory system has the strongest direct
Speaker 1: line to the hippocampus and the amygdala, which are the
Speaker 1: memory and emotional centers of the brain. This is why
Speaker 1: sent memories can evoke such powerful feelings of nostalgia. A
Speaker 1: smell can carry us back to a specific time and
Speaker 1: place in ways that conscious thinking and remembering just can't.
Speaker 1: That might explain why we find the smell of baby
Speaker 1: powder so soothing. It summons feelings of security and love
Speaker 1: from deep in our earliest memories. But even that smell
Speaker 1: appears to have cultural variations. Americans associate the new baby
Speaker 1: smell with vanilla and powdery sense, while the French associate
Speaker 1: babies with the scent of orange blossoms. For some people,
Speaker 1: the smell of sunscreen is a stress reliever since it
Speaker 1: reminds them of care free summer days at the beach,
Speaker 1: and so if work is stressing you out, consider stowing
Speaker 1: a squeeze bottle of sp of fifty in your desk.
Speaker 1: Today's episode is based on the article what makes a
Speaker 1: sense soothing on houseuff works dot com, written by Dave Rouse.
Speaker 1: Brain stuff It's production offi Heart Radio in partnership with
Speaker 1: how Stuff Works to dot Com was produced by Tyler
Speaker 1: Playing and Ramsay Young. Four more podcasts from my heart
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