“I didn't start consuming caffeine until I came to university. I was definitely one of those ‘caffeine-naive’ individuals,” says Daniel Borota. Borota is an undergraduate science student who turned his newfound interest in America’s favorite morning stimulant into an important new piece of scientific research, published online this week in Nature Neuroscience.
Finding he was enjoying his morning cup of java, Borota, working under the guidance of Michael Yassa, assistant professor of psychological and brain sciences in the Krieger School of Arts and Sciences at Johns Hopkins, wondered about the effects that caffeine might have on cognition. He searched the research literature and found little to answer his questions.
Subsequently, Borota, Yassa, and a team of researchers conducted a double-blind trial that worked this way: Volunteer participants were “caffeine-naive” like Borota. They did not regularly consume caffeinated products (including certain soft drinks and supplements) prior to the study. But for the study, they received either a placebo or a 200-milligram caffeine tablet (equivalent to one cup of strong coffee) five minutes after studying a series of images. The experiment was double blind. No one, including the researchers, knew which subjects received which tablet.
The next day, both groups were tested for their ability to recognize images from the previous day's study session. On the test, some of the visuals were the same as from the day before, some were new, and some were similar but not the exactly the same as the items previously viewed. More members of the caffeine group were able to correctly identify the new images as "similar" to previously viewed images versus erroneously citing them as the same.
The brain's ability to recognize the difference between two similar, but not identical, images is called pattern separation. Neuroscientists see it as a reflection of a level of memory retention deeper than simple recognition. "[Pattern separation] requires the brain to make a more difficult discrimination…which seems to be the process that is enhanced by caffeine,” Yassa explains. “Memory is malleable—it can be strengthened or weakened. In this study, we demonstrated that caffeine may help strengthen long-term memory or make it more resistant to forgetting,” says Borota.
Borota explains further: “The study was unique because it was a direct test of caffeine's effect on memory consolidation. By administering caffeine after participants completed the study phase, we controlled for caffeine's performance enhancing-effects, such as increased alertness and attention, which may have showed up as a boost in memory. As a result, we can say with confidence that caffeine has memory-enhancing effects independent from these other cognitive effects, which have been well-documented.”
Yassa says that the next step is to use brain-imaging techniques to discover the mechanisms that underlie the enhancement. "We also know that caffeine is associated with healthy longevity and may have some protective effects from cognitive decline like Alzheimer's disease. These are certainly important questions for the future," he says.
On a practical level, Borota advises moderation in caffeine consumption. “Drinking coffee before going to bed is not a good idea,” he says. “Although caffeine has an enhancing effect on memory, sleep is very important for memory; sleep deprivation (as would occur with too much coffee) can have negative effects for memory.”
For More Information (to explore during the morning coffee break):
Daniel Borota, Elizabeth Murray, Gizem Keceli, 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, published online Jan 12, 2014.
Yassa Lab (now at UC-Irvine)
See a video about the study here. http://yassalab.org/2014/01/13/new-paper-post-study-caffeine-administrat...