Smell a freshly baked apple pie and it transports you back to childhood and the first time you smelled apple pie baking. We have all had the experience where a particular smell has brought us back to a time and place of memory.There’s no telling when a “limbic moment” will hit you, but thanks to that ancient part of the brain, you have direct access to your past through the sense of smell.
The limbic system is part of the reptilian brain, the older embryological part of brain that is one of the first to form as a fetus. It is the interface between the brain and the outside world. The limbic system is the seat of the emotional center and is partly responsible for our fight or flight response, our emotional reaction to something, our hormonal secretions, motivation, pain reflex and our mood fluctuations. There are three main components to the limbic system: the hypothalamus, the hippocampus and the amygdalae. There are also the pituitary, the cingulate gyrus, the fornicate gyrus, the thalamus, the mammilary body, the nucleus accumbens that help form the system, plus the olfactory bulb that plays such an important part in aromatherapy.
How does all this work?
An aroma fills the room and the smell is inhaled. Odorant molecules infiltrate the nasal passages and travel through to the olfactory epithelium where neurons with cilia bind onto the odorant. The odorant receptors in the neurons bind to an odorant molecule. The receptor cells then convert the proteins into electrical impulses.Odor impulses travel directly to the olfactory cortex in the temporal lobe or to the limbic system (especially the hypothalamus and pituitary).
Aromatherapy and the Sense of Smell
Each of the essential oils has therapeutic properties, in that they are stimulating, calming, sedative, balancing, etc. When we inhale an essential oil molecule, it travels through the nasal passage to a receptor neuron that transports it up to the limbic brain, especially the hypothalamus. An essential oil that has a vibrationally calming effect on the body causes the hypothalamus to receive the input to relax, then it creates neurochemicals that are sent through the body to relax and calm. Likewise if an essential oil has a frequency known to stimulate the body, then the limbic system will conform by sending the message to energize and become more active. Through this manner of transport, one can understand how aromatherapy oils can increase immunity, balance hormonal secretions, dampen or enliven hunger and thirst, and create sexual desire. Each time the same aroma is present with a similar pleasure, the pathways deepens, until the memory transfers from short term to long term memory and is indelibly planted in the brain. Then years after the event, even if the smell hasn’t been present all that time, one whiff and the brain falls right back into the pleasure pathways and the memories kick in. The same applies for ‘bad’ memories. The unpleasant external events associated with the aroma become internalized and are remembered by the stimulus of the odor. An arousal or fight/flight state is triggered in the limbic system by the direct access of the aroma molecule.
Aromatherapy can play a big part in stress reduction, balanced heart rate, hunger control and sexual desire, all because of its inter-relationship with the limbic system. Whether the oils are rubbed on in massage oil or inhaled through an aroma lamp, the odor molecules will travel to their limbic destination and create the appropriate neurochemicals to affect a physical response. So the next time you smell something that transports you back in time, you can hum “thanks for the memory” to your limbic system.
Another way that essential oils enter the body is inhalation through the nose or mouth.his in more detail.)
"Smell is a potent wizard that transports us across thousands of miles and all the years we have lived." Helen Keller
Reference from http://www.suzannebovenizer.com/aromatherapy-essential-oils/the-limbic-system