Study Finds Alcohol Dampens Brain Waves Associated With Decision-Making But Not Motor Control


Source: San Diego State University

Summary: A new study sheds light on the question of why people feel like they are in complete control of their actions when they’re drinking even while their cognitive control is clearly impaired.


We all know that alcohol impairs our judgement, alertness and performance on tasks requiring attention, but the mechanism behind booze’s effect on cognition still isn’t well-understood. A new study led by the psychologists at San Diego State University sheds light on the question of why people feel like they are in complete control of their actions when they’re drinking even while their cognitive control is clearly impaired. The results could help explain what goes on at the neural level when people who’ve been drinking decide they’re okay to drive. The results suggest that alcohol primarily induces deficits during decision-making, and not while executing motor commands. The study findings were published in the journal PLOS ONE.

Alcohol affect on brain

A new SDSU study takes a deeper look into alcohol’s effect on cognition. Credit: San Diego State University

The research team recruited 18 young, healthy volunteers to participate in an experiment measuring their cognitive control while distracted. The volunteers sat in a brain imaging machine called a MEG scanner and watched a series of colored squares appear on a screen. First, two squares of the same color would appear on either side, followed by a single square flashing in the middle of the screen. At times, the middle square’s color would match the two side squares and sometimes it would be different. Participants were instructed to ignore the color of the side squares and press a button corresponding to the color of the middle square. The research team found that after participants drank alcohol, their beta waves during the color-choosing task seemed perfectly normal, but their theta waves dropped sharply in frequency.

Co-author Lauren Beaton said, “However, occasionally we have to quickly react to stimuli, such as when a car cuts you off. You must be able to override automaticity and use cognitive control to safely navigate the situation. But when drivers are intoxicated, they are less successful at making these quick changes.”


More Information: Lauren E. Beaton et al, “When the brain changes its mind: Oscillatory dynamics of conflict processing and response switching in a flanker task during alcohol challenge”, PLOS ONE (2018). DOI: 10.1371/journal.pone.0191200


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