Scientists testing the effects of coffee and regular caffeine found that regular caffeine only partially replicated the effects of drinking a cup of coffee, activating areas of the brain that make you feel more alert but not areas of the brain that affect working memory and goal-directed behavior.
For many people, the day only begins when their coffee cup is empty. Coffee is often thought to make you feel more alert, so people drink it to wake up and improve their performance. Portuguese scientists studied coffee drinkers to understand whether the wakefulness effect is due to the properties of caffeine or the experience of drinking coffee.
“There is a common belief that coffee increases alertness and psychomotor performance,” said Prof. Nuno Sousa of the University of Minho, corresponding author of the study Frontiers in Behavioral Neuroscience and editor-in-chief of the journal Field. “When you better understand the mechanisms underlying a biological phenomenon, you open up paths to exploring factors that might modulate it and even the potential benefits of that mechanism.”
Caffeine for starters
The researchers recruited people who drank at least one cup of coffee a day and asked them to refrain from eating or drinking caffeinated beverages for at least three hours before the study. They interviewed the participants to collect sociodemographic data, then performed two brief functional MRI scans: one before and one 30 minutes after taking caffeine or drinking a standard cup of coffee. During the functional MRI scans, the participants were asked to relax and let their minds wander.
Given the known neurochemical effects of coffee drinking, the researchers expected the functional magnetic resonance imaging scans to show that coffee drinkers had greater integration of networks related to the prefrontal cortex, associated with executive memory, and the default mode network, involved in introspection and self-reflective processes. They found that the connectivity of the default mode network decreased after both coffee and caffeine consumption, indicating that consuming caffeine or coffee made people more prepared to transition from rest to working on tasks.
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Waking up on the right side of the bed
However, drinking coffee also increased connectivity in higher visual network and the actual executive control network—parts of the brain involved in working memory, cognitive control, and goal-directed behavior. This didn’t happen when participants took caffeine alone. In other words, if you want to feel not only alert but ready to act, caffeine alone won’t cut it—you’ve got to try that cup of coffee.
“Acute coffee consumption reduced functional connectivity between brain regions of the default mode network, a network that is associated with self-referential processes when participants are in a resting state,” said Dr. Maria Picó-Pérez of Jaume I University, first author. “Functional connectivity was also reduced between somatosensory/motor networks and the prefrontal cortex, while connectivity in areas of the higher visual network and the right executive control network increased after coffee consumption. In brief, participants were more ready to act and more alert to external stimuli after drinking coffee.”
“Given that some of the effects we found were reproduced by caffeine, we might expect other caffeinated beverages to have similar effects,” Picó-Pérez added. “However, others were specific to coffee drinking, driven by factors such as the specific smell and taste of the beverage or psychological expectations associated with consuming it.”
The authors pointed out that it’s possible that the experience of drinking coffee without caffeine could be causing these benefits: this study couldn’t distinguish the effects of the experience alone from the experience combined with caffeine. There’s also the hypothesis that the benefits reported by coffee lovers could be due to relief from withdrawal symptoms, which this study didn’t test.
“Connectivity changes were examined during resting-state sequences. Any associations with psychological and cognitive processes are interpreted based on the common function attributed to the regions and networks found, but were not directly tested,” Sousa warns. “Moreover, there may be individual differences in caffeine metabolism among participants that would be fascinating to investigate in the future.”
