Alcohol Reconfigures Brain Networks into Local Clusters

A double-blind, placebo-controlled study of 107 healthy social drinkers used resting-state fMRI and graph-theory analysis to show that acute alcohol intake (0.08 BAC) shifts the brain from a globally integrated network to a more fragmented, locally connected topology: global efficiency drops (notably in the occipital cortex) while local efficiency and clustering rise, effectively fracturing the brain into smaller communities. The insula also increases local connections, and these network changes correlate with how intoxicated participants felt. The findings offer a neural basis for alcohol-related sensory deficits and individual differences in intoxication, though limitations include incomplete cerebellum data and a young, healthy sample. Overall, intoxication appears to trade long-range integration for localized processing.