When you feel mentally drained, two regions in your brain may quietly decide whether to keep going or give up. They assess the effort needed and weigh it against potential rewards. This process helps explain why tasks can feel overwhelming when your mind is fatigued. Understanding it could reveal how motivation influences mental endurance.
Recent studies reveal that mental exhaustion isn’t just a feeling—it’s a biological process involving specific regions of the brain. These areas seem to gauge the “cost” of continuing effort and whether external incentives are enough to push through challenges.
How two brain regions determine if you give up or keep going
Researchers at Johns Hopkins Medicine used functional MRI to study volunteers performing demanding memory tasks. They discovered two key regions that activate when participants experience cognitive fatigue: the right insula, which is linked to feelings of tiredness, and the dorsolateral prefrontal cortex, responsible for working memory and complex decision-making. Activity in both regions more than doubled during difficult tasks compared to baseline levels.
The study involved 28 healthy adults aged 21 to 29. Participants were paid $50 to take part and could earn additional payments based on performance. Tasks required recalling the position of letters shown in sequence on a screen, with difficulty increasing as the series grew longer. After each round, participants rated their fatigue and received feedback and optional higher incentives ($1–$8) to continue.
Results showed that participants were more likely to exert extra cognitive effort only when financial incentives were high. This finding suggests that motivation can override feelings of mental fatigue, highlighting the brain’s ability to weigh effort against reward. This finding highlights how the brain constantly balances effort and reward, even in everyday decisions, shaping how we respond to mental challenges.
“Our research shows that these two brain areas may work together to regulate cognitive effort, essentially deciding when to push or pause,” explained Dr. Vikram Chib, associate professor of biomedical engineering at Johns Hopkins University School of Medicine.
The implications are significant for people with conditions like depression or PTSD, who often experience overwhelming cognitive fatigue. Mapping these neural circuits could help physicians evaluate and treat fatigue more effectively, using therapies or interventions designed to target these specific brain regions.
Functional MRI, which measures blood flow as a proxy for brain activity, allowed scientists to observe these patterns in real time. While it doesn’t capture individual neuron activity, it provides a broader picture of how the brain responds under mental strain.
Future research aims to see whether these findings apply to real-world tasks beyond controlled memory exercises. Understanding how cognitive fatigue manifests could guide new treatments, including cognitive behavioral therapy or medication, to help people persevere when mental effort feels exhausting.
Ultimately, this research emphasizes that fatigue isn’t simply about willpower—it’s a complex interaction between brain function, perceived effort, and motivation. Recognizing the role of these two brain regions could transform how we approach mental exhaustion and productivity.
Even small incentives can sometimes make a big difference, proving that the brain’s decision to keep going or stop is as much about reward as it is about fatigue.