Core Insights - The research indicates that the brain's energy consumption during focused cognitive tasks is only about 5% higher than in a resting state, challenging the perception that deep thinking is significantly more energy-intensive [1][4][6] - The brain's primary function is to maintain operations and manage physiological systems rather than solely focusing on explicit cognitive tasks [2][5][6] Energy Consumption - The human brain accounts for approximately 20% of the body's energy resources despite only comprising about 2% of body weight, with infants consuming nearly 50% [3][6] - Energy for brain function primarily comes from ATP, synthesized from glucose and oxygen, with a vast network of capillaries supplying these resources [3][4] Cognitive Activity - The study reveals that even when not actively engaged in tasks, the brain is highly active, managing internal physiological parameters and maintaining homeostasis [5][6] - The brain's "default mode network" operates during rest, processing thoughts related to past, present, and future experiences [5][6] Evolutionary Perspective - The brain's energy efficiency is a result of evolutionary adaptations to resource-scarce environments, leading to a natural tendency to conserve energy [6][7] - The optimal firing rate of neurons is significantly lower than theoretical limits, indicating an evolutionary strategy focused on maximizing information transfer efficiency while minimizing energy expenditure [7][8]