Acute Alcohol Intake Produces Widespread Decreases in Cortical Resting Signal Variability in Healthy Social Drinkers

Abstract

Background: Acute alcohol intoxication has wide-ranging neurobehavioral effects on psychomotor, attentional, inhibitory, and memory-related cognitive processes. These effects are mirrored in disruption of neural metabolism, functional activation, and functional network coherence. Metrics of intraregional neural dynamics such as regional signal variability (RSV) and brain entropy (BEN) may capture unique aspects of neural functional capacity in healthy and clinical populations; however, alcohol's influence on these metrics is unclear. The present study aimed to elucidate the influence of acute alcohol intoxication on RSV and to clarify these effects with subsequent BEN analyses.

Methods: 26 healthy adults between 25 and 45 years of age (65.4% women) participated in 2 counterbalanced sessions. In one, participants consumed a beverage containing alcohol sufficient to produce a breath alcohol concentration of 0.08 g/dl. In the other, they consumed a placebo beverage. Approximately 35 minutes after beverage consumption, participants completed a 9-minute resting-state fMRI scan. Whole-brain, voxel-wise standard deviation was used to assess RSV, which was compared between sessions. Within clusters displaying alterations in RSV, sample entropy was calculated to assess BEN.

Results: Compared to the placebo, alcohol intake resulted in widespread reductions in RSV in the bilateral middle frontal, right inferior frontal, right superior frontal, bilateral posterior cingulate, bilateral middle temporal, right supramarginal gyri, and bilateral inferior parietal lobule. Within these clusters, significant reductions in BEN were found in the bilateral middle frontal and right superior frontal gyri. No effects were noted in subcortical or cerebellar areas.

Conclusions: Findings indicate that alcohol intake produces diffuse reductions in RSV among structures associated with attentional processes. Within these structures, signal complexity was also reduced in a subset of frontal regions. Neurobehavioral effects of acute alcohol consumption may be partially driven by disruption of intraregional neural dynamics among regions involved in higher-order cognitive and attentional processes.

Keywords: Acute Alcohol Intoxication; Entropy; Resting State; Signal Variability; fMRI.

© 2020 Research Society on Alcoholism.

Figures

Figure 1.

Transverse sections showing distribution and extent of clusters where alcohol significant reduced RSV compared to placebo, beginning at Z = −22 mm and ventral to dorsal by 4mm per slice to Z = 70mm. Images are presented in neurological orientation. BA: Brodmann area, MTG: middle temporal gyrus, IFG: inferior frontal gyrus, MFG: middle frontal gyrus, IPL: inferior parietal lobule, SFG: superior frontal gyrus, SMG: supramarginal gyrus, PCG: posterior cingulate gyrus.

Figure 2.

Transverse sections showing distribution and extent of clusters where alcohol reduced BEN relative to the placebo condition (small-volume corrected pFWE