Aromatic Associations

Aromatic Associations

Laura Shanahan’s article “Scents and Reminiscence: Olfactory Influences on Memory Consolidation in the Sleeping Human Brain'' provides a unique perspective into the extensive impact the olfactory system has with memory. The use of sensory cues, known as targeted memory reactivation, or TMR, is utilized in this study in order to find effective translational research uses to solidify and manipulate declarative and emotional memories. In a similar lens, a recent article was published by the University of Fukui “Smell you later: Exposure to smells in early infancy can modulate adult behavior” explored the phenomenon in which newborn mice “imprint” onto scents that ultimately affect their future social behaviors. With the knowledge that mammals such as mice and humans are both social animals, the long term impact found in the olfactory association is a topic that is necessary to understand due to its impact on social behavior. 

Dr. Shanahan’s research not only correlates memory to the olfactory system, but implements the use of such methods into the sleep cycle to find potential effects that would result from such exposure. Using both positively and negatively perceived aromas, subjects were trained, exposed in their sleep, and recorded once again once awoken to find detectable differences that would be a result of the sleep exposure. An interesting aspect that I found in the study was the fact that the use of TMR led to promising results in fear extinction when previously exposed to negative olfactory stimuli.

Dr. Nobuko Inoue along with their team explored a question that also pertained to the use of smells in memory retention. Specifically, this correlation was discovered between newborn mice and the odors they are exposed to during a critical period. This critical period, only lasting a week, is a result of the interaction between Sema7A, a signaling molecule, and the receptor PlxnC1. During this time, scents that are detected are all positively correlated due to the release of oxytocin from this interaction. Although this appears to be a good system, difficulty arises when newborn mice are exposed to an aversive scent, the mice will now be conflicted for the rest of its life due to the positive correlation from imprinting and the negative correlation from their natural response. Although this exact pattern has not been seen in humans, it is important to note that this critical period may apply to other sensory inputs that can lead to long term effects to newborns. Ultimately, the importance of the olfactory system in animals such as mice and humans extends beyond its immediate use, and extends itself to the implementation of memories that may affect those exposed for their entire life.  Although much of the process in either studies are heavily unknown, the relation between potential fear extinction and its similarity to Dr. Nobuko Inoue’s research on the impact of negative olfactory stimuli during the critical period of newborn mice is interesting to see. 

Work Cited:

Shanahan, Laura K., and Jay A. Gottfried. “Scents and Reminiscence: Olfactory Influences on Memory Consolidation in the Sleeping Human Brain.” Cognitive Neuroscience of Memory Consolidation Studies in Neuroscience, Psychology and Behavioral Economics, 2017, pp. 335–346., doi:10.1007/978-3-319-45066-7_20.

“Smell You Later: Exposure to Smells in Early Infancy Can Modulate Adult Behavior.” ScienceDaily, ScienceDaily, 13 Apr. 2021, www.sciencedaily.com/releases/2021/04/210413110645.htm.