Oscillatory spatial profile of alcohol's effects on the resting state: Anatomically-constrained MEG

Abstract

It has been firmly established that opening and closing the eyes strongly modulate the electro- and magnetoencephalography (EEG and MEG) signals acquired during wakeful rest. Certain features of the resting EEG are altered in chronic alcoholics and their offspring, and have been proposed as biomarkers for alcoholism. Spontaneous brain oscillations are also affected by pharmacological manipulations, but the spectral and spatial characteristics of these changes are not clear. This study examined effects of the eyes-open (EO) and eyes-closed (EC) resting paradigm and alcohol challenge on the spatial profile of spontaneous MEG and EEG oscillations. Whole-head MEG and scalp EEG signals were acquired simultaneously from healthy social drinkers (n = 17) who participated in both alcohol (0.6 g/kg ethanol for men, 0.55 g/kg for women) and placebo conditions in a counterbalanced design. Power of the signal was calculated with Fast Fourier Transform and was decomposed into its constituent theta (4–7 Hz), alpha (8–12 Hz), and beta (15–20 Hz) frequency bands. High-resolution structural MRI images were additionally obtained from all participants and used to constrain distributed minimum norm inverse source power estimates. The spatial estimates of the main generator nodes were in agreement with studies using a combined fMRI-EEG approach. Alpha band oscillations dominated the spectral profile and their source was estimated to the medial parieto-occipital area. Power in theta and beta bands was weaker overall and their sources were estimated to a more focal medial prefrontal area. EO and EC manipulation most strongly modulated power in the alpha band, but a wide-band power increase was observed during the EC condition. Alcohol intoxication increased alpha power, particularly during the EC condition. Application of this methodology to cohorts of chronic alcoholics or individuals at risk could potentially provide insight into the neural basis of oscillatory differences that may be predictive of the vulnerability to alcoholism.

Exploratory Analysis of Power Spectrum and Functional Connectivity During Resting State in Young Binge Drinkers: A MEG Study

“…Thus, the decrease in alpha band in occipital areas of the BD group may be related to a deficit in memory compatible with cognitive studies with this population showing deficits in memory tasks 21,22,75 . Besides, a recent study has shown that acute alcohol intoxication also affects alpha band, increasing its short-term power mainly during eye-closed resting state, also measured by MEG 76 . Therefore, it would be possible that a pattern of consumption that includes repeated alcohol intoxication, as BD, affects long-term PS and, specifically to alpha power.…”

High-intensity binge drinking is associated with alterations in spontaneous neural oscillations in young adults

“…Acute alcohol intoxication induces a decrease in alpha oscillatory frequency and an increase in alpha power (Ehlers, Wall, & Schuckit, 1989; Nikulin, Nikulina, Yamashita, Rossi, & Kahkonen, 2005). Source modeling of the MEG signal has confirmed that alpha power is generated primarily in the medial parieto-occipital area and is increased during alcohol challenge (Rosen et al, 2014). Studies of rsEEG reveal lower alpha power in individuals with alcohol use disorder (AUD) (Begleiter & Platz, 1972; Saletu-Zyhlarz et al, 2004) who also exhibit a low-voltage alpha (LVA) variant that is comorbid with high anxiety (Enoch & Goldman, 1999).…”

“…Electro- and magnetoencephalography (EEG and MEG) are used to measure spontaneous neural oscillations during wakeful rest, also termed resting-state, rsEEG/MEG (Rosen et al, 2014; Schomer & Lopes da Silva, 2011). Because it does not require any task engagement, this method has been applied across ages and in diverse populations to examine spontaneous oscillations in various brain-based disorders and conditions (Porjesz et al, 2005; Schomer & Lopes da Silva, 2011) including chronic alcoholism (Begleiter & Porjesz, 2006; Porjesz et al, 2005; Rangaswamy & Porjesz, 2014).…”

“…Spontaneous theta and beta oscillations reflect anteriorly localized rhythms (Rosen et al, 2014), and are altered as a function of acute and chronic alcohol exposure (Rangaswamy et al, 2003; Rangaswamy et al, 2002; Stenberg, Sano, Rosen, & Ingvar, 1994). Increased power in theta and beta bands has previously been observed in acutely intoxicated, healthy participants (Rosen et al, 2014; Stenberg et al, 1994).…”

The use of magnetoencephalography in the study of psychopharmacology (pharmaco-MEG)

“…Interestingly, simultaneous EEG recordings showed no differences, suggesting that MEG had superior sensitivity than EEG. Similarly, Rosen et al (2014) showed that alcohol (0.6 g/kg men/0.55 g/kg women, oral) strongly increased alpha power in eyes-closed conditions with minimum norm source estimates, identifying sources in the medial occipitoparietal area. Small increases in theta and beta were also seen with alcohol localised to the anterior cingulate cortex.…”