For many people, the morning routine is incomplete without a hot cup of coffee.
The caffeine in coffee helps shake off the morning grogginess and sharpen focus for the tasks ahead. But beyond the temporary alertness, what is coffee actually doing to your brain?
A new study published in June 2023 in Frontiers in Behavioral Neuroscience sheds light on how coffee changes functional connectivity within various brain networks.
Coffee, Caffeine, and Brain Connectivity
The study looked at habitual coffee drinkers and examined their brain connectivity patterns using fMRI scans taken before and after drinking coffee. The researchers found that coffee consumption decreased connectivity within the posterior default mode network (DMN), which is involved in internal thought processes like mind wandering and rumination.
The DMN is a network of brain regions that activate when the brain is at wakeful rest, not focused on any particular task. Increased DMN activity is associated with being lost in thought, daydreaming, and rumination. Decreased DMN activity allows the brain to focus outwards and engage goal-directed networks for completing tasks.
Coffee also decreased connectivity between somatosensory/motor regions and the prefrontal cortex. Importantly, consuming caffeine alone replicated the decreased posterior DMN connectivity. This suggests caffeine is the primary ingredient responsible for reducing mind wandering and preparing the brain for focused activity.
The DMN, Depression, and Coffee
The DMN has also been implicated in major depressive disorder. Multiple studies have found that individuals living with or at high risk for depression showed increased DMN connectivity.
Rumination, or repetitive negative thoughts, is a core symptom of depression. Rumination is associated with increased DMN activity and dysfunctional connectivity between the DMN and cognitive control regions. This excessive self-focused rumination makes it difficult to disengage from negative thought patterns.
The decreased DMN connectivity observed after coffee consumption may relate to coffee’s potential antidepressant effects. By reducing rumination and mind wandering, coffee could help explain its ability to improve mood in some individuals.
The caffeine in coffee appears to “reboot” the brain, allowing depressed individuals to deactivate the DMN and engage in more focused, goal-directed thinking.
Beyond Caffeine: The Multisensory Aspect
Interestingly, coffee also increased connectivity in the higher visual and right executive control networks, which are involved in visual processing, working memory, and cognitive control. However, caffeine alone did not impact these networks in the same way.
The researchers propose that components of coffee beyond caffeine may enhance connectivity in regions related to sensory processing and cognitive control. The multisensory ritual of preparing and drinking coffee appears to have additional effects, engaging brain networks involved in reward, pleasure, and imagination.
Coffee as a Brain Booster
While the subjective alertness boost from coffee is well known, these studies provide objective evidence on how coffee and caffeine change functional brain connectivity.
The ability to disengage the default mode network and prepare for focused activity sheds light on why so many people depend on their morning coffee routine. The sensory pleasure of drinking coffee engages additional networks as well.
So while caffeine alone can increase alertness by changing specific networks, the experience of drinking coffee impacts connectivity more broadly, altering networks involved in sensory, reward, cognitive, and potentially mood regulation.
