Katie Jabaay's Post
Power of Scent
Scent is a powerful tool to creatures on this Earth. Odors alert organisms to threats, food, mates, and other important aspects to life while also being retained and influential to the storage of memories. Scent in humans has all of those traits and more, as we can explicitly label scents and have deep associations with both good and bad memories, especially in those with mental illnesses. Two articles touch on olfaction’s effect on humans are “What the nose knows” and “Something doesn’t smell right” respectively written by Colleen Walsh and Peter Reuele of Harvard University.
The article “What the nose knows” gives the succinct explanation of the connection between scent and emotion. Taking the more literary route, the article describes the initiation of a memory via a specific smell as a Proustian moment. The article goes on to explain that the connection between the olfactory bulb, the amygdala and the hippocampus heavily contribute to the connection smell has to one’s emotion and memory. Smell is so immersive and crucial to one’s experience that it forms one's sense of taste, creates a signature brand for companies, becomes associated with colors, and creates a foundation of childhood memories that will create likes and dislikes for ages. The monopolization of scent was a focal point of the article, as it is a relatively new phenomenon to use scents on normally non-scented products in order to appeal to a specific audience or outcompete others. Creating scented products for a clothing line, making film that pairs with scented air, and fragrant hotels are new markets that are on the rise and being researched and pushed by scientists such as Dawn Goldworm, Venkatesh Murthy, and David Edwards.
While the previous article focuses on the positive sides of smell, the second article, “Something doesn’t smell right,” explains the recent finding of a specific olfactory sensor that is specific for rancid odors. Trace amine-associated receptors, or TAARs, are specific receptors in the olfactory bulb that are entirely distinct from the average, and more populous, odorant receptors. TAARs are specifically activated during the sensation of cadaverine and putrescine scents, meaning they are specifically geared towards smells of rotting and death. These receptors, for most animals, send the message that something is wrong, making those smells bad. The fact that creatures are born with these receptors provides evidence for the idea that animals, and even humans, have scents that are innately labeled as bad; this means that smell preferences are in fact partially influenced by genetics rather than only socialization and associations.
Connecting to these ideals is the article "Odor modulates the temporal dynamics of fear memory consolidation" by Grella et al., where the effects of odor on the encoding and storage of memory is explored. The study focused on three theories, being the systems consolidation, competitive trace and multiple trace theory. Systems consolidation theory states that with time memories become less detailed with time and consequently change from being stored in the hippocampus to the prefrontal cortex. Multiple trace theory states that the episodic and semantic memories, as in memories with high levels of detail, are stored in the hippocampus, whereas less detailed memories are stored in the prefrontal cortex. Competitive trace elaborates these ideas and states that though memories become more remote with time, they can also be re-contextualized. Mice with PTSD had problems with the fear conditioned memories since they were stored in the hippocampus and were readily available instead of being stored remotely in the prefrontal cortex. The connection to the previous articles lies in the fact that the genetically modified mice were fear conditioned, pairing specific scents and electric shocks. The mice learned to associate the scents with the shock, causing a fear response from the mere odor, and the fear-memory was readily available in the hippocampus.
The reason that the “What the nose knows” and “Something doesn’t smell right” connect to the paper by Grella et al. is that there are many possible implications of the work. If Walsh’s predictions are true and scent can really be utilized for intentional and successful marketing, then this can be taken to the extreme with the knowledge that some scents are innately good or bad. Finding a receptor for an inherently good scent could maximize the marketing of anything from clothing to vacations, and perhaps a more likely first step could be using it in pet treats or toys since it can be easier to determine animals’ innately good or bad receptors. In a similar fashion, there could be the possibility for those with PTSD and other mental illnesses with symptoms triggered by scents be trained with new, innately pleasant scents during therapy. Since there is the possibility for naturally pleasant and enticing odors and there’s the knowledge that PTSD memories are held as new and adaptable in the brain, associating a new and pleasant emotion with a traumatic memory could potentially ease the negative response with the natural positive one. However, steps would need to be taken to regulate the amount of positive odors that are used in order to not associate more scents with a traumatic memory or response. More broadly, positive scents could be used during therapy to facilitate the eliciting positive emotions and negating the negative ones during emotionally taxing conversations. Overall, odors are an overlooked aspect to daily life, marketing, research, and therapeutic treatments for how influential it is to human and animal neurology. More research into this topic could yield a flourishing new market and possible improvement for the treatment of those with mental illnesses.
Bibliography
Grella, Stephanie L., et al. “Odor Modulates the Temporal Dynamics of Fear Memory Consolidation.” Learning and Memory, 2019, https://doi.org/10.1101/2019.12.19.881615.
Reuell, Peter. “Something Doesn't Smell Right.” Harvard Gazette, Harvard Gazette, 15 Jan. 2014, https://news.harvard.edu/gazette/story/2014/01/something-doesnt-smell-right/.
Walsh, Colleen. “How Scent, Emotion, and Memory Are Intertwined - and Exploited.” Harvard Gazette, Harvard Gazette, 27 Feb. 2020, https://news.harvard.edu/gazette/story/2020/02/how- scent-emotion-and-memory-are-intertwined-and-exploited/.
