Alcohol increases spontaneous BOLD signal fluctuations in the visual network

Area of Science:

• Neuroscience
• Neuroimaging
• Pharmacology

Background:

• Resting wakefulness exhibits slow (<0.1Hz) blood oxygenation level-dependent (BOLD) fluctuations in functional magnetic resonance imaging (fMRI) signals.
• These BOLD signal fluctuations are organized into distinct resting-state networks (RSNs).
• Understanding alcohol's effects on brain networks is crucial for cognitive and perceptual research.

Purpose of the Study:

• To investigate network-specific changes in resting-state fMRI (RS-fMRI) signals induced by acute alcohol administration.
• To determine if alcohol selectively affects certain RSNs.
• To examine the temporal dynamics of alcohol's impact on brain connectivity.

Main Methods:

• RS-fMRI scans were performed on eight healthy subjects before and after a 0.7 g/kg dose of ethyl alcohol.
• Control experiments were conducted on separate days without alcohol.
• Independent component analysis (ICA) was used for dynamic network analysis to extract RSN maps.

Main Results:

• Alcohol significantly increased the strength of the visual network ICA component, peaking at 90 minutes post-administration.
• Within the visual network, alcohol's effect was stronger in primary occipital cortex regions compared to secondary occipito-temporal regions.
• Other major RSNs (default-mode, fronto-parietal, sensori-motor, self-referential, auditory) showed no significant alcohol-induced changes.

Conclusions:

• Acute alcohol administration selectively targets the visual system, enhancing resting-state functional connectivity.
• The visual network is a primary target of acute alcohol effects.
• Enhanced BOLD fluctuations in the primary visual cortex may disrupt visual processing and perception.