How smells control our brain.

One of the symptoms of coronavirus infection, which the world has been struggling with for almost 2 years, is loss of smell. Initially, this symptom was ignored, as it was believed that there were much worse ravages in the body caused by the infection. However, it turns out that long-term loss of smell may be associated with depression and deterioration of quality of life ¹ . The proof is the new discoveries of scientists about the powerful impact that smell has on our lives.

How do we remember smells?

“Smells are an elusive phenomenon. They cannot be named well (...) they cannot be immortalized," wrote Constance Classen, David Howes and Anthony Synnott in their book "Aroma: A Cultural History of Fragrance." The book was published in 1994, and since then scientists have made significant progress in research on this elusive sense.

For example, researchers from Northwestern University Feinberg School of Medicine in the USA concluded that there is a previously unrecognized neurobiological pathway connecting the sense of smell and memory areas of the brain. ² . This discovery was considered a breakthrough. It turned out that there is a very strong connection between the hippocampus (the memory center in the brain, which stores memories) and the human olfactory areas. This is why scents trigger such strong emotional reactions in us. Of all the senses, smell has the strongest connection with the head.

The smell reaches directly to the brain.

"The human brain has changed during evolution," Christina Zelano, a professor at Northwestern University and the lead author of the study, explains to journalists. "Over the years, there has been an expansion of the neocortex, involved in, among other things, receiving and processing sensory impressions, which has slightly modified the access of the senses to memory. Vision, hearing and touch are connected to the hippocampus via the association cortex, not directly. According to In our research, smell is the only sense that has retained direct access to the memory storage center of the hippocampus, " said the researcher. ³ .

Few people realize that smells are an important part of memory and connect us with memories that are important to us. The smell of a Christmas tree and gingerbread reminds us of Christmas time. The scent of old perfume will remind you of life events that coincided with the use of this aroma. Smells can transport our mind in time and space, evoke emotions and even tears, but also calm and comfort us.

Nobel Prize for research on genes related to smells.

Smell is inextricably linked with taste - these types of sensations are perceived by the brain at the same time. This sense is sensitive to the so-called odorants, i.e. chemical compounds present in the air. He remained mysterious for a very long time. However, research gained new dynamics at the end of the last century, thanks to, among others, the "Human Genome Project". It turned out that olfactory receptors are the largest group in the human genome .

Earlier, in the early 1990s, researchers Linda Buck and Richard Axel published work that solved the mystery of how the olfactory apparatus and sense of smell functioned. American scientists have described what happens to smell along the nose-brain route. And the aroma goes to the receptors, the olfactory bulb, then to the glomerulus and the appropriate places in the cerebral cortex. There, a pattern is then created that allows you to differentiate smells and assign memories to them. This discovery won them the Nobel Prize in 2004 ⁴ .

The artist Sissel Tolaas, who a few years ago was the patron of the "Smell" exhibition at the Copernicus Science Center in Warsaw, is based, among other things, on their research. In one of the interviews, the artist, who created scent maps of many cities and eras , said: " We learn much more through smell than when we simply look at someone. The nose knows and transmits information much faster than the other senses. In our world, the nose is used subconsciously, and I wonder what would happen if we consciously used it. ⁵ .

Odors affect not only our brain. This knowledge has been used since ancient times. Aromatic substances and essential oils have been used for thousands of years to improve mental well-being and health. If you want to learn more about how aromatherapy works, check out here .

Bibliography:

1. Hur K., Choi JS, Zheng M., Shen J., Wrobel B., “Association of alterations in smell and taste with depression in older adults.” Laryngoscope Investig Otolaryngol. February 21, 2018.
2. Guangyu Z., Olofsson JK, Koubeissi MZ et al., “Human hippocampal connectivity is stronger in olfaction than other sensory systems.” Progress in Neurobiology, 2021.
3. Niewińska - Lewicka A., "We know more about how scents evoke memories." Naukawpolsce.pl, March 11, 2021
4. “The Nobel Prize in Physiology or Medicine 2004”, nobelprize.org, accessed December 14, 2021.
5. Dudek A., “When a person cries, he smells different than when he loves. And what does fear smell like? Polskatimes.pl, January 1, 2014