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Abstract:
Given the effect of acute alcohol intake on the human emotional state, we hypothesized that even a moderate dose of alcohol will affect the brain activity of social drinkers, both at rest (default-mode network, DMN) and when passively viewing emotional stimuli, in terms of functional connectivity.
Electroencephalographic (EEG) recordings were performed on 27 participants after receiving an alcoholic beverage and placebo respectively, at rest and during passive viewing of affective images from the International Affective Picture System (IAPS). The selected images were representative of 4 categories: pleasant and high arousing, pleasant and low arousing, unpleasant and high arousing and unpleasant and low arousing. Salivary alcohol served to measure the inebriation levels. The activity of cortical sources was estimated with the standardized Low Resolution Electromagnetic Tomography (sLORETA). The magnitude square coherence (MSC) on each pair of them was estimated for each frequency band to form functional networks among the cortical sources. The networks were treated in the context of graph theory and their global parameters were calculated.
Our preliminary results refer to the DMN connectivity. The MSC averaged across all sources' pairs, along with the global efficiency of the DMN, were significantly (p < 0.05) higher following alcohol intake (vs. placebo) in alpha and beta bands. The inter-connectivity of certain nodes, roughly outlining the DMN, was elevated (p < .05 corrected) in alpha band during alcohol sessions indicating a pronounced baseline functional connectivity.
Our findings support the hypothesis that alcohol affects the functional connectivity of the DMN not necessarily locally, but in a more global way. A resting state pronounced functional connectivity in the human brain can elucidate to an extent the attention impairment already observed following acute alcohol intake, since the transition to an attentive state would be more demanding. Extensive functional connectivity analysis is underway in order to examine the effect of acute alcohol intake on the connectivity patterns eliciting during passive viewing of emotional stimuli examining whether it is different for different kinds of affective images.
As expected, measures that globally quantify the brain functional connectivity were sensitively affected by alcohol-induced alterations in the DMN. We will soon have some findings on the functional networks formed as a response to emotional stimuli following inebriation.
