The Role of Aerobic Glycolysis in the Resting Human Brain

Transient regional increases in brain activity associated with task performance result in elevated glucose metabolism greater than the corresponding increase in oxygen consumption (aerobic glycolysis). Aerobic glycolysis is also present in the resting adult brain but neither its regional pattern nor its mission is known. We studied the distribution of aerobic glycolysis in the resting human brain using positron emission tomography to measure glucose and oxygen utilization in 33 healthy young adults. The default system and dorsolateral prefrontal cortex bilaterally showed metabolic rates significantly above the brain mean and had high levels of aerobic glycolysis. However, sensory cortices, particularly primary visual cortex, while also exhibiting equally high metabolic rates, did not exhibit elevated glycolysis. The cerebellum, whose energy consumption is close to the brain mean, had the lowest levels of aerobic glycolysis. Our data demonstrates heterogenic distribution of aerobic glycolysis in the human brain and indicate that the most pronounced elevation in aerobic glycolysis occurs in regions characterized by high functional activity at the resting state.