Learning about emotions and essential oils

Oils affect our emotions. There is a beautiful book written called Emotions and Essential Oils. It lists the emotional and spiritual effects of certain essential oils. I remember the first time I looked at this book. My thought was how can an oil have effects like this? I never really verbalized this question. As I have tested out the emotional qualities of these oils, the effects are sometimes astounding in the abilities to support on an emotional level. However, as I am starting to share the oils, I am finding this is a question that I need to figure out how to explain.
I remember the first time I ever tried an oil. I was struggling with a time of depression. It was bad enough that I reached out to my friend, who became my mentor, asking her if she knew of anything I could try that could help me. She was fairly new to the world of essential oils and was constantly talking about the things she was learning about. She gave me a sample of a citrus blend (Citrus Bliss). The effects were instant. My fog lifted. Over time, I learned and realized what I needed to do to take care of the cause of the depression. But I was able to do that because there was something available to support me.
Recently, I was talking with a friend. Her sweet little 5 year old accidentally saw something some time ago in a short intense clip that was on the internet involving evil clowns. This child has since had periodic episodes of intense terror. These episodes of terror stay with the child for a long time after mom is able to get this child to calm down. There is nothing that can be said to calm the child, it is only Mom's comforting arms that is able to do that. Well, as we were visiting, her child went into a room alone to do something, and suddenly we heard terrified screams. This child was seeing in their mind's eye, that horrible clown.When Mom came out with her child after going in to the rescue, the child was shaking and clinging to Mom. I was flipping through my Emotions book and came across Juniper Berry which was said to have the effect to help people have courage to face their fears. I had the child smell the oil and asked if it smelt okay. When I got an affirmative answer, I asked if I could put some where it could be smelled and again got an affirmative answer. So I put a tiny amount behind each ear and on the forehead (less than a drop total).
What surprised my friend was within 10 minutes, this child was off playing and laughing and ran outside with the rest of the kids. She said that normally this child would be clinging to her for hours because of how terrifying the experience is.
We called my mentor for help explaining why the emotional effect. My mentor gave an excellent explanation. Here is in essence what she told us.
Sometimes we feel emotions that are primal. Fear and anger are key primal emotions. These deep primal feelings are so intense that words are not able to reach them. In fact someone trying to tell us something to make us feel better can even make things worse. They are not rational and can not be rationalized. The place that these feelings are processed are in the limbic system within the heart of the brain. Essential oils are composed of tiny molecules. When inhaled (smelled) they are able to cross the barriers and directly affect this limbic system.
While there is still much I have to study to understand this, and research I must find, this made sense. I remember learning several years back in my anatomy and physiology classes that it is the senses that directly affect the limbic system, whether to cause them, make them worse or make them better.
I found some great diagrams to help illustrate this: