What is it about the smell of a rose?

This morning while I was walking in the nearby woodland I was suddenly catapulted back in time by the smell of crushed leaves - I imagine the dog I had just seen running by had scrambled through them. The memory that came to me was vivid visually and emotionally, a small event, something I haven't thought about for too many years.

This has happened to me often throughout my life - the smell of a dark red old fashioned rose reminds me of being a small child in my grandmother's garden, happy and carefree - the smell of jasmine conjures up the mass of flowers growing outside my bedroom when I was a teenager together with a heady feeling of infinite possibility- rain falling on hot dry earth recalls the heavenly scent of Zululand bush and a magical day spent with a close friend. I have often wondered how a smell can be remembered and also call up the associated visual and emotional memory.

Marcel Proust (French novelist - 1871 - 1922) wrote “When from a long distant past nothing subsists, after the people are dead, after the things are broken and scattered, taste and smell alone, more fragile but enduring, more unsubstantial, more persistent, more faithful, remain poised a long time, like souls, remembering, waiting, hoping, amid the ruins of all the rest; and bear unflinchingly, in the tiny and almost impalpable drop of their essence, the vast structure of recollection.”

When Proust wrote that, the brain was still much of a mystery to scientists. Proust maintained that smell and taste alone had the ability to recall emotional memories and that looking at visual forms did not do the same.

I am inclined to agree wholeheartedly - even looking through albums of treasured photos doesn't bring back the stir of emotion that belongs to the time the photos were taken.

I've discovered that olfactory memory - that's what it's called - is a very important survival mechanism.  we need to be able to recognise smells to remember when we experience something, whether it means we are about to have a good experience (food, sex) or a bad one (rotten food).

This is how smell works - the odour molecule is absorbed in the nasal passage. It binds to a chemo-receptor specific to that particular type of smell and heads to the olfactory bulb as an electrical signal. From there the signal is transmitted to the limbic system of the brain. The limbic system compares the signal to other stored signals to identify it.

The limbic system also stores memories and mediates emotions. Apparently somehow when the odour is first recorded, the emotion and visual event that is happening at that moment is also recorded as a part of the same memory. Obviously the scientific explanation is a lot more complex and difficult to understand.

People who suffer from Alzheimers disease apparently have impaired olfactory memory, and mental disorders such as  depression can be assessed by the particular pattern of deficiency in olfactory memory.

This magical ability to bring back a memory through the sense of smell is something we don't think about and take for granted but I hope that I will now pay more attention and be grateful the next time my nose calls back the past.

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