The findings could lead the way to understanding the brain’s intake and output of energy in good health and bad and the part that alcohol plays.
In previous studies, the researchers have shown that alcohol significantly affects brain glucose metabolism, a measure of energy use, as well as regional brain activity, assessed through changes in blood oxygenation. But regional differences in glucose metabolism are hard to interpret, they say. In a study with healthy volunteers, they used brain imaging techniques to help quantify “match and mismatch” in energy consumption and expenditure across the brain—what they termed power and cost.
The researchers assessed power by observing to what extent brain regions are active and use energy, and cost by observing how brain regions expended energy. They found that different brain regions that serve distinct functions have “notably different power and different cost.”
Next, they tested a group of light drinkers and heavy drinkers and found both acute and chronic exposure to alcohol affected power and cost. In heavy drinkers, the researchers say, they saw less regional power, for example, in the thalamus, the sensory gateway, and frontal cortex. The researchers interpreted the decreases in power as reflecting the toxic effects of long-term exposure to alcohol on the brain cells.
They also found power dropped in the visual regions during acute alcohol exposure, which was related to disruption of visual processing. Visual regions also had the most significant drops in cost of activity during intoxication. That is consistent with the reliance of those regions on alternative energy sources, such as acetate (a byproduct of alcohol metabolism), the researchers say.
Their approach for characterizing brain energetic patterns related to alcohol use could be useful in other ways, the researchers say. “Studying energetic signatures of brain regions in different neuropsychiatric diseases is an important future direction,” said co-lead investigator Dr. Ehsan Schokri-Kojori. “The measures of power and cost may provide new multimodal biomarkers.”