Brain activity inhibition during Short Video Viewing: neurochemical insights

Cognitive control enables individuals to adapt to the ever-changing environmental demands. The dorsal anterior cingulate cortex (dACC) and the dorsolateral prefrontal cortex (dlPFC) are key regions of the cognitive control network, activated during cognitively demanding tasks. In contrast, the entertaining and habitual nature of short-video consumption for leisure shifts neural processing toward emotional engagement and immediate gratification, contributing to excessive use and diminished self-control in some individuals. This raises a critical question: Does short-video viewing suppress cognitive control regions, and what neurochemical factors may underlie individual differences in this process? To address this question, this preregistered study used proton magnetic resonance spectroscopy ( 1 H-MRS) to measure glutamate and γ-aminobutyric acid (GABA) concentrations in the dACC at rest, and employed functional magnetic resonance imaging (fMRI) to examine dACC and dlPFC activity during free viewing of short videos in 56 young adults. We found that both the dACC and the dlPFC exhibited significant deactivation in response to preferred videos that were watched to completion, compared to less-preferred videos that were terminated early. Moreover, resting-state glutamate levels in the dACC were associated with the magnitude of this deactivation, with higher glutamate concentrations associated with less suppression of both dACC and dlPFC activity. Additionally, functional connectivity between the dACC and dlPFC increased during video viewing, particularly for preferred videos. By integrating fMRI with 1 H-MRS, our study provides novel evidence that immersive viewing of preferred short videos deactivates the cognitive control network and that individual differences in this deactivation are linked to glutamate metabolism. These findings enhance our understanding of how digital media consumption interacts with neurochemical processes to influence self-regulation. Our study offers new insights into the neural mechanisms underlying short-video engagement and has implications for understanding excessive digital media use.