The scent of memory

Are you too invol­un­t­a­rily thin­king of a specific place or person when you smell a certain scent? Memory and smell are linked in ways we don’t yet fully understand.

Now, a new study suggests that smells during sleep may posi­tively affect some aspects of cogni­tive func­tion and circuitry important for memory and cognition.

In the U.S. study, elderly adults were “scented” with diffe­rent essen­tial oils for 2 hours each night for six months — causing a statis­ti­cally signi­fi­cant impro­ve­ment in memory perfor­mance. The Rey Audi­tory Verbal Lear­ning Test attested a statis­ti­cally signi­fi­cant impro­ve­ment of 226% compared to the control group. Func­tional magnetic reso­nance imaging (fMRI) studies showed improved func­tion of the left unci­nate fasci­culus, an area of the brain asso­ciated with memory and cogni­tion whose func­tion normally declines with age.

Impro­ving our memory perfor­mance through such simple measures as aroma­the­rapy while we sleep seems an enti­cing pros­pect. But please be careful when trying it yourself: espe­ci­ally for asth­ma­tics, infants and small children, the actually bene­fi­cial scents can be irri­ta­ting. And some fumes are not suitable for dogs and cats either.

Woo, Cynthia C et al. “Over­night olfac­tory enrich­ment using an odorant diffuser improves memory and modi­fies the unci­nate fasci­culus in older adults.” Fron­tiers in neuro­sci­ence 2023.