Dose-dependent effects of intravenous alcohol administration on cerebral blood flow in young adults.

Functional magnetic resonance imaging (fMRI) studies involving alcohol challenge are important for identifying neural correlates of alcohol's psychopharmacological effects. However, evaluating acute alcohol effects on blood oxygen level-dependent (BOLD) signal change is complicated by alcohol-related increases in cerebral blood flow (CBF). The present study aimed to further characterize acute alcohol effects on CBF using intravenous alcohol administration to maximize control over brain alcohol exposure. Twenty heavy-drinking young adults (M = 19.95 years old, SD = 0.76) completed alcohol and placebo imaging sessions in a within-subject, counter-balanced, placebo-controlled design. Arterial spin labeling (ASL) provided estimates of perfusion change at two target blood alcohol concentrations (40 and 80 mg%) relative to baseline and relative to a saline control infusion. Voxel-wise analyses showed widespread and dose-dependent effects of alcohol on CBF increase. Region-of-interest analyses confirmed these findings, also indicating regional variation in the magnitude of perfusion change. Additional findings indicated that lower self-reported sensitivity to alcohol corresponded with reduced perfusion change during alcohol administration. This study provides further evidence for widespread effects of acute alcohol on cerebral perfusion, also demonstrating regional, dose-dependent, and inter-individual variation. Further research is needed to evaluate implications of these effects for the design and interpretation of pharmacological fMRI studies involving alcohol challenge.