Sleep and odor memory

Was searching for something quite different when I came across a paper discussing how sleep helps with odor memory.*

In one part of this study, the participants (who were all male, btw) learned to recognize six different odors (though not name them). Then they slept, and the next day were asked to identify which odors they had or had not experienced the night before from among a set of twelve odors. 

By administering certain drugs or placebo just before sleep, the researchers were able to determine that the participants consolidated their memory for the odors during slow-wave deep sleep. 

The graph below shows the results of one part of the study. In the wake condition (on the left), participants were kept awake through the night. While their recognition ability under this condition was good, it was not as good as their ability after a period (3 hours) of slow-wave sleep, followed by staying awake (compare Placebo/Wake to Placebo/Sleep). The drug clonidine obliterated the effect of slow-wave sleep on recognition. 

Was fascinated to observe that the odors they used included several that are typical in tea, such as linalool oxides, damascenone, and 2-hexenal.** 

Conclusion: if you want to learn to recognize (and eventually name, of course) different odors in tea, it helps to get a good night’s sleep!

* Gais S, Rasch B, Dahmen J, Sara S, Born J. The Memory Function of Noradrenergic Activity in Non-REM Sleep. Journal Of Cognitive Neuroscience [serial online]. September 2011;23(9):2582-2592. Available from: Academic Search Premier, Ipswich, MA. Accessed October 26, 2016.

** Incidentally, the authors qualified these odors as being “unfamiliar”— but they probably are familiar to those of you who have been studying tea aromas.