The Brain's Energy Budget: Why Focus Leads to Fatigue

New research unveils the secrets of the brain's energy efficiency. The brain operates far more efficiently than previously thought, a legacy of our ancestors' evolution in energy-scarce environments. Even at rest, the brain performs extensive background tasks, including prediction and maintaining homeostasis. Intense mental activity significantly increases energy consumption, explaining why prolonged focus leads to fatigue. The brain has evolved mechanisms to limit energy expenditure, such as reducing neuronal firing rates and synaptic transmission efficiency, maximizing information transmission efficiency per energy unit. This research provides insights into the brain's mechanisms and the limits of human cognitive capacity.