Newswise — The emptying of a coffee mug often marks the official start of the day for many individuals. The belief that coffee enhances alertness leads people to consume it in order to awaken themselves and enhance their productivity. In an effort to comprehend whether this wakefulness effect is solely attributed to the properties of caffeine or if it relates to the act of drinking coffee itself, a group of Portuguese scientists conducted a study on coffee enthusiasts.

Prof. Nuno Sousa from the University of Minho, who served as the corresponding author of the study published in Frontiers in Behavioral Neuroscience and acted as the Field Chief Editor of the journal, stated, "There is a widespread anticipation that coffee boosts alertness and psychomotor performance. By gaining a deeper understanding of the mechanisms underlying this biological phenomenon, we pave the way for investigating the factors that can influence it and even exploring the potential advantages of those mechanisms."

A caffeine kickstart

To investigate the impact of coffee consumption on brain activity, the researchers enlisted individuals who consumed a minimum of one cup of coffee per day. Prior to the study, the participants were instructed to abstain from consuming any caffeinated beverages or food for at least three hours. Sociodemographic information was gathered through interviews, and two brief functional MRI (fMRI) scans were conducted: one before and another 30 minutes after either ingesting caffeine or consuming a standardized cup of coffee. During the fMRI scans, the participants were instructed to relax and allow their minds to wander.

Considering the well-established neurochemical effects of coffee consumption, the scientists anticipated that the fMRI scans would reveal increased connectivity among networks associated with the prefrontal cortex, known for its involvement in executive memory, and the default mode network, responsible for introspection and self-reflection processes. Surprisingly, the connectivity of the default mode network was observed to decrease following both coffee consumption and caffeine intake. This suggests that consuming either caffeine or coffee heightened individuals' readiness to transition from a state of rest to engaging in task-related activities.

Waking up on the right side of the bed

However, the effects of drinking coffee went beyond the expected changes in the default mode network. It was found that coffee consumption increased connectivity in the higher visual network and the right executive control network, which are regions of the brain associated with working memory, cognitive control, and goal-directed behavior. Interestingly, this heightened connectivity was not observed when participants solely consumed caffeine without the coffee-drinking experience. In other words, if one desires not just alertness but also a sense of readiness and preparedness, caffeine alone is insufficient—it is the actual act of drinking coffee that provides this effect.

Dr. Maria Picó-Pérez from Jaume I University, the study's first author, explained, "Acute coffee consumption resulted in a decrease in functional connectivity between brain regions of the default mode network, which is typically active during self-reflection in resting conditions. Additionally, the connectivity between somatosensory/motor networks and the prefrontal cortex decreased, while the connectivity within regions of the higher visual and right executive control networks increased after consuming coffee. Put simply, individuals exhibited a heightened state of preparedness, being more responsive and attentive to external stimuli after drinking coffee."

"Considering that some of the effects observed in our study were also evident with caffeine alone, it is plausible to assume that other caffeinated beverages may share similar effects," added Picó-Pérez. "However, certain effects were specific to coffee consumption, likely influenced by factors such as the distinct aroma and taste of coffee or the psychological expectations associated with consuming this particular beverage."

The authors acknowledged that the benefits observed could potentially arise from the experience of drinking coffee itself, independent of the caffeine content. Unfortunately, this study was unable to distinguish the effects of the experience alone from those combined with caffeine. Additionally, the hypothesis that the perceived benefits reported by coffee-drinkers might be attributed to the relief of withdrawal symptoms was not tested in this study.

"The changes in connectivity were examined during a resting-state sequence, and any association with psychological and cognitive processes is inferred based on the recognized functions of the identified regions and networks. However, direct testing of these associations was not performed," Sousa cautioned. "Furthermore, individual differences in caffeine metabolism among participants could exist, which would be worthwhile to explore in future research."


Journal Link: Frontiers in Behavioral Neuroscience