Expanding on the Topic of Odor’s Relationship with Fear

Have you ever been suddenly struck with a scent that transported you back in time, to a flashbulb memory? Suddenly, you are remembering your mother’s cooking, a holiday event, or the perfume of a lost friend. Odor is a significant cue for recall, especially with the emotional concept of fear. In the article “Odor Modulates the Temporal Dynamics of Fear Memory Consolidation”(2020) the researchers, Grella et al., inspected the idea of reorganization of fear memories by the influence of odor stimuli at the system level, all in support of the system consolidation theory. Odor presented to have control in the dynamic of how the fear memories were reorganized. Keeping this study in mind, one may research and analyze various articles focused on formulating new fear memories with the aid of odor stimuli to probe the limitations of odor’s impact on the recollection of pain and danger.

The Frontiers in Neuroscience Journal included an article named “An Evolutionarily Threat-Relevant Odor Strengthens Human Fear Memory”(2020), Jessica E. Taylor et al., explored the association of fear memories and 2-methyl-2-thiazoline odor, a threat-relevant predatory odor. The researchers attempted to distinguish a possible linear relationship between exposure to an odor and contextual enhancement during the construction of fear memories. In preference to establishing odor as a cue of already encoded fear factors, this study aimed to investigate once the subject forms new fear memories with odor as contextual modification, would they express a stronger behavioral reaction during recall due to the olfactory process.

The study involved forty females from Japan. The author mentioned that this decision was made to omit “the potentially confounding factor of sex on conditioning (Dalla and Shors, 2009; Inslicht et al., 2013) and to [increase the] reliably measure [of] skin conductance” (Tayor). All subjects rated various odors on a scale of -5 to 5 based on absolute pleasantness for a score of positive five to general subjective ‘like’ for the score of  negative five. Control ‘extinction’ odors, such as seirogan, jalapeño brine, or black bean paste, were used alongside 2-methyl-2-thiazoline odor, the experimental condition, for the experimental group. The control group did not experience the 2-methyl-2-thiazoline odor. In the statistical analysis, the ANOVA presented a significant difference for the neutral odor conditioned stimulus. Thus, a paired sample t-test was performed and demonstrated a significant difference for the unconditioned predatory odor against the conditioned stimulus. The 2-methyl-2-thiazoline odor revealed a higher expectancy than the randomized conditioned stimulus odor. Further evaluation and replication of the study can aid the population in discovering how modifying odor capability and conditioned training can aid disorders such as PTSD and improve daily life functions.

Works Cited

Grella, S. L., Fortin, A. H., McKissick, O., Leblanc, H., & Ramirez, S. (2020). Odor modulates    

the temporal dynamics of fear memory consolidation. Learning & Memory, 27(4), 150–163. https://doi.org/10.1101/lm.050690.119 

Taylor, J. E., Lau, H., Seymour, B., Nakae, A., Sumioka, H., Kawato, M., & Koizumi, A. 

(2020).An evolutionarily threat-relevant odor strengthens human fear memory. Frontiers in Neuroscience, 14, 1–12. https://doi.org/10.3389/fnins.2020.00255