Updated: Mar 6, 2020
Have you noticed how a particular smell can remind you of a place or person or other memory?
Our sense of smell starts in the upper most parts of our nasal cavity by nerves of the olfactory bulb. The olfactory bulb is part of the brain's limbic system, an area so closely associated with memory and feeling it's sometimes called the "emotional brain.” Smells can call up memories and powerful responses almost instantaneously.
The olfactory bulb has a strong relationship with the limbic system, especially the amygdala, which processes emotion, and the hippocampus, which is responsible for associative learning. In other words, smells trigger memories and emotions associated to places and times.
When we smell a new scent, our brain embeds a link between the smell and a linked memory emotion.
The smell of rain on concrete may remind you of watching a rainstorm with your grandmother or the smell of cut grass might bring back fond memories of your father mowing the lawn. Every time you encounter that smell, the code is there to elicit a memory or a mood.
Researchers have determined we begin linking smell and emotion before we're even born. During fetal development, olfaction evolves to permit the infant after birth to find its mother. Infants who are exposed to alcohol, cigarette smoke or garlic in the womb show a preference for the smells. To them, these smells that might upset other babies seem normal or even comforting. Ninety percent of your sense of taste is reliant on smell. Our eating habits are largely driven by smell memories.
The olfactory nerve via intranasal delivery can transfer medications directly to the brain.
Our sense of smell is so intertwined with our brain, scientists have tapped the olfactory system to deliver therapeutic compounds to the brain. This is called intra nasal delivery. Smells, and other chemicals are quickly taken up by the olfactory bulb and transferred into the brain. This efficient and rapid delivery system bypasses the blood brain barrier. The blood brain barrier consists of a tight layer of endothelial cells in our blood vessels surrounded by astrocyte foot processes from the brain, and these anatomic features constitute a significant barrier to drug transport from the blood to the brain. This blood brain barrier is a safety mechanism whereby our blood vessels regulate or limit the passage of chemicals into the brain. Because the olfactory nerve is so intimately connected to the amygdala, nasal uptake can result in concentrated delivery of medications to the regions of our emotional Limbic System.
Intranasal delivery of medications is very useful in medicine. Indications where new nose-to-brain products are likely to emerge include the following: neurodegeneration, post-traumatic stress disorder, pain, and glioblastoma. There are lots of common nasal delivery products available including Nasadol CBD Nasal Spray, Sprix for pain control, Noctiva for bedwetting, Migranal, Imitrex and Zomig for migraine pain, Instanyl for cancer pain, Nascobal for vitamin B12 deficiency, Ketamine for acute suicidal ideation, and Narcan for opoid overdose. Just to list a few.
Nasal CBD may be the most effective way to get CBD directly to the regions of the Limbic System that are involved in anxiety, stress, pain, memory and other emotional perceptions. Scientists are learning more and more every day about the Limbic System and how CBD is beneficial to overall brain health.
Here’s my take home prescription:
Our sense of smell is powerfully connected to the emotional, processing and learning parts of our brain. The olfactory nerve, the cranial nerve responsible for the sense of smell transfers more than just smells to the brain and can deliver concentrated medications and CBD rapidly and efficiently into the brain, bypassing the blood brain barrier. These properties explain why intranasal CBD can be so effective. We will continue to learn more about the mechanisms by which CBD exerts its beneficial effects on the brain as more and more research centers begin to look at CBD.