Brain’s energy restored during sleep, suggests animal study
June 30, 2010
In the initial stages of sleep, energy levels increase dramatically in brain regions found to be active during waking hours, according to new research in the June 30 issue of the Journal of Neuroscience.
These results suggest that a surge of cellular energy may replenish brain processes needed to function normally while awake.
Levels of adenosine triphosphate (ATP), the energy currency of cells, in rats increased in four key brain regions normally active during wakefulness. Shown here is the energy surge measured in the frontal cortex, a brain region associated with higher-level thinking. (Dworak et al. The Journal of Neuroscience 2010)
The authors measured levels of adenosine triphosphate (ATP), the energy currency of cells, in rats. They found that ATP levels in four key brain regions normally active during wakefulness increased when the rats were in non-REM sleep, but were accompanied by an overall decrease in brain activity. When the animals were awake, ATP levels were steady. When the rats were gently nudged to stay awake three or six hours past their normal sleep times, there was no increase in ATP.
The authors conclude that sleep is necessary for this ATP energy surge, as keeping the rats awake prevented the surge. The energy increase may then power restorative processes absent during wakefulness, because brain cells consume large amounts of energy just performing daily waking functions.
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