Regular caffeine only partially reproduces the effects of drinking a cup of coffee, activating brain regions that make you feel more alert, but not the brain regions that influence working memory and goal-directed behavior, according to new research.
There is a general expectation, namely among regular coffee drinkers, that coffee increases alertness and psychomotor functioning.
For these reasons, many people continue to drink coffee to combat fatigue, stay alert, improve cognitive performance, and increase work efficiency.
Coffee drinks are composed of numerous compounds known to influence human behavior, including caffeine and chlorogenic acids.
From a neurobiological perspective, both caffeine and chlorogenic acids have well-documented psychoactive actions, while caffeine is mostly an antagonist of major adenosine receptors in the brain, leading to the disinhibition of excitatory neurotransmitter release and enhancement of dopamine transmission to sharpen brain metabolism and enhance memory performance; Chlorogenic acids may directly affect neuronal performance through mechanisms that have yet to be understood.
While the neurochemical action of these compounds appears to be reasonably understood, the psychological effect of coffee/caffeine, while largely real, remains a matter of debate and must be considered in the context of its use.
“There is a general expectation that coffee increases alertness and psychomotor functioning,” said Professor Nuno Sousa of the University of Minho.
“When you better understand the mechanisms underlying a biological phenomenon, you open avenues for exploring the factors that can modulate it and even the potential benefits of that mechanism.”
For their study, Professor Sousa and colleagues recruited people who drank at least one cup of coffee a day and asked them not to eat or drink caffeinated beverages for at least three hours before the study.
They interviewed the participants to collect sociodemographic data and then did two short functional MRI scans: one before and one 30 minutes after ingesting caffeine or drinking a standardized cup of coffee.
During the functional MRI scans, participants were asked to relax and let their mind wander.
Because of the known neurochemical effects of drinking coffee, the researchers expected that the functional MRI scans would show that the people who drank coffee had higher integration of networks linked to the prefrontal cortex, associated with executive memory, and the default mode network. involved in processes of introspection and self-reflection.
They found that default mode network connectivity decreased both after drinking coffee and after taking caffeine, indicating that consuming caffeine or coffee made people more willing to transition from rest to work on tasks.
However, drinking coffee also increased connectivity in the higher visual network and right executive control network – areas of the brain involved in working memory, cognitive control and goal-directed behavior.
This did not happen when participants only took caffeine. In other words, if you want to not only feel alert, but also be ready to go, caffeine alone is not enough – you have to experience that cup of coffee.
“Acute coffee consumption reduced functional connectivity between brain regions of the default mode network, a network associated with self-referential processes when participants are at rest,” says Dr Maria Picó-Pérez of Jaume I University.
“Functional connectivity was also decreased between the somatosensory/motor networks and the prefrontal cortex, while connectivity in regions of the higher visual and right executive control network was increased after drinking coffee.”
“In short, the subjects were more ready for action and more alert to external stimuli after drinking coffee.”
“If we take into account that some of the effects we found were reproduced by caffeine, we might expect other caffeinated beverages to share some of the effects.”
“Others, however, were specific to drinking coffee, driven by factors such as the drink’s specific smell and taste, or the psychological expectation associated with consuming that drink.”
The scientists pointed out that it’s possible that the experience of drinking decaffeinated coffee could trigger these benefits.
The study was unable to distinguish the effects of the experience alone from the experience combined with the caffeine.
There is also a hypothesis that the benefits claimed by coffee drinkers may be due to the relief of withdrawal symptoms, which was not tested in this study.
“The changes in connectivity were studied during a range of resting states,” Professor Sousa said.
“Any association with psychological and cognitive processes is interpreted based on the common function attributed to the regions and networks found, but was not directly tested.”
“In addition, there may be individual differences in caffeine metabolism between participants that would be interesting to investigate in the future.”
The research has been published in the journal Frontiers in behavioral neuroscience.
Maria Pico-Perez et al. 2023. Coffee consumption reduces connectivity of the posterior Default Mode Network (DMN) at rest. Front side. Behavior Neuroscience 17; doi: 10.3389/fnbeh.2023.1176382