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

Rationale: 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). Objectives: The present study aimed to further characterize acute alcohol effects on CBF using intravenous alcohol administration to maximize control over brain alcohol exposure. Methods: 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. Results: 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. Conclusions: 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.