Good news for all coffee lovers — coffee can not only perk you up but also boost your long term memory! A recent study from Dr. Michael A. Yassa and colleagues found that taking 200mg caffeine, equal to two small cups or one large cup of coffee, shortly after study can help with memory consolidation.
In this study, participants incidentally studied pictures of objects, such as basket, seahorse etc. Immediately after this, they received either a tablet containing 200mg caffeine or a placebo. Next day, 24 hours after studying the pictures, participants returned to the lab to identify the pictures from a mixture of "old" ones (the same as previous day), "new" ones (different objects compared with previous day) and "similar" ones (slightly different from previous day, e.g. a basket with one handle and a "similar" one with two handles).
Fig. 1: Brief workflow of the experiment. On the first day, participants studied the pictures. This is a process of information encodingin the brain. Soon after this, participants received either 200mg caffeine or placebo. The information needs time to be stored or called "consolidation". On the second day, participants had a test to recall the information to identify a mixture of pictures as "old", "new" or "similar". The difference in the ability to identify these pictures reveals the effect of caffeine on memory consolidation.
(Picture modified from Michael A. Yassa et al./Nature Neuroscience)
Interestingly, both the caffeine group and placebo group could successfully identify the "old" and "new" pictures. However, many participants from the placebo group failed to recognize the subtle alterations in the "similar" pictures but identified them as "old" ones, while a higher ratio of participants from the caffeine group could distinguish the small changes between them. This result showed that caffeine really helped people to determine what makes similar pictures different. This ability is called pattern separation, a deeper level of memory retention in hippocampus, the memory center in the brain.
However, if you want to drink more coffee to memorize better, probably it will not work, because the researchers also found that 300mg caffeine did no significant difference from 200mg. The appropriate caffeine amount may differ from individuals, two cups may be sufficient for the people who don't drink coffee often but not enough for the people who usually drink five cups per day. And we all know that sleep is the best way for the consolidation of memory, therefore, there's no reason to drink coffee before sleep, either.
Even though the discovery of this study is quite impressive, we need also pay attention to the small sample of 160 participants and relatively small effect of caffeine in this experiment. A larger sample would be surely more convincing. Besides,what are the molecular mechanisms of the caffeine's effect on memory consolidation? This remains an open question. If caffeine's effect could be eventually proved in a molecular level, then, we can expect that one day we will make pills from coffee beans to improve our memory and help the old populations who have memory or cognitive problems.
Borota, Daniel, Elizabeth Murray, GizemKeceli, Allen Chang, Joseph M. Watabe, Maria Ly, John P. Toscano, and Michael A. Yassa. "Post-study caffeine administration enhances memory consolidation in humans." Nature neuroscience (2014)