Scientists investigating how the brain uses energy have found that effortful, goal-directed tasks use only 5% more energy than restful brain activity.
The majority of the brain’s function goes into background maintenance, regulating physiological systems and allocating resources where they are needed.
The human brain uses around 20% of the body’s energy despite accounting for just 2% of its weight, with infants’ brains using even more.
Neurons send information at a deliberately slow rate – around four hertz on average – to ensure the brain doesn’t use more energy than it needs.
Increasingly, neuroscientists are focusing on how the brain operates beneath the surface, away from active, outward cognition such as attention, problem-solving and decision-making.
They are uncovering a hidden hive of activity in the brain’s background processing that is essential for regulating the body and keeping it alive.
The findings reveal evolutionarily-imposed limitations on the scope and efficiency of human cognitive capabilities.
