Friday, April 4, 2014

Do you smell that?

Photos this week are selected to elicit a memory of smell
I had just parked my car on a busy street in Oakland when it hit me ...someone was cooking fried chicken!  The smell was overwhelming ...I haven't smelled fried chicken like that since my Aunt Cecile used to cook up several of her fryers for a large Sunday gathering.  As I walked on to my meeting I noticed the smell of wet Eucalyptus leaves after a spring rain,  then, when I entered my destination,  I picked up the odor of a science laboratory.  
Fried Chicken - Baken potati - Purple Cabbage Salad
For me smell is a powerful stimulant of memories and associations. (I even have occasional dreams involving smell.)  And the amazing thing is that, over the years,  the memory of smells is slow to fade.  The small of our musty basement from my childhood is still there, the first whiff of lilacs each spring, the smell of jet exhaust fumes at the airport ( which I find exciting!) , the hint in the air of a far off skunk smell (rather pleasant for me...) , freshly baked bread (memories of childhood),   wet dogs (walks with our pups), a barn filled with bales of summer alfalfa ( sweet fragrance! ) .
Bread baked in a backyard wood fired oven
I have my smell biases too.  I hate the smell of too much perfume on a woman in an elevator.  I have negative feelings toward spray-on air fresheners (the ones, with names like "Spring Breeze" and "Flower Garden", "Autumn Rain" - when in fact they were designed and born in an industrial chemical plant. Yuck!  In the same category I put room potpourri mixes often made of rose petals treated with noxious artificial smells!  Chemically scented Christmas candles too!  Hate them!  I prefer the smells of the natural world.

Harvesting grapes

My dogs seem to take smell even more seriously than me. I wonder if the brain of a dog is organized in a way to remember smells much as learning and knowledge is stored in my brain.  Our pups will linger at a fence post or bush and deeply smell over and over the smells of their "colleagues" who have visited this stop.  It seems deeply important to them.

Our pup - Rusty
There are specialized nerve cells in a small patch of tissue in back of the nasal cavity.  Each of these cells has hair like extensions (cilia) that are in direct contact with air.  Molecules from the things we smell act as a stimulus.  When stimulated, an electric signal is sent to the brain.    When you take a breath you draw air, with molecules of odor, over this region. 
Gasoline powered farm tractor - exhaust smoke
Taste by contract is much more limited - Our tongue has receptors that only detect sweet, sour, salty, and bitter... Anything more is really us responding to the aroma of our foods close in our mouth/nose region. (You all have experienced not being able to taste when our nose is stopped by a cold).  And what subtle nuances we can smell/taste...! We can detect the difference between Coke and Pepsi, between a Gravenstein apple and a Granny Smith, between a Cabernet and a Merlot, Gouda and a Monterey Jack, between a ripe banana and an almost ripe banana. 

Market place in Bishkek Kyrgystan- here smells of many sources assail ones nose!

In it in the brain that real ‘smell’ happens! We relate our smell perceptions to past experiences and to our stored memory bank of past smell experiences.  It is possible to train your "palate" to be more able to identify smell/flavors.  In addition, smell information is projected through a pathway to the central nervous system, which controls emotions.  Do you have an emotional response to Lilacs or Red roses? the smell of a high performance raceway…? It happens here!
High Mountain air is pure and only lightly scented with mountain herbs and trees
Odor sensation depends on the number of molecules available to the olfactory receptors. Different smell molecules are recognized by combinations of receptors, the patterns of neuron signals helps us to identify the smell. The olfactory system does not interpret a single compound, but instead the whole smell mix. 

So the next time you smell frying chicken - breath deeply ... think about all those responding neurons signaling your brain - the activation of your smell memory bank - and your decision how you feel about what you are smelling - what memories and associates it stirs up.  Wow!

If you lived on a farm - pre-plumbing - you can never forget this smell!