Regional Brain Entropy During Movie-watching

Brain entropy (BEN) measures the irregularity or unpredictability of brain activity. Our previous studies have showcased the neurocorrelates and disease sensitivity of regional BEN. Task performance and neuromodulations as well as medications can modulate regional BEN. Movie-watching engages multiple-domain cognitions and complex brain activities mimicking the complex real world and has been increasingly used to probe brain state dynamics. The sustained multiple-domain cognitive activities would cause sustained changes to regional BEN, which however remains unknown. The purpose of this study was to address this gap. We first aimed to examine whether the fMRI-derived regional BEN represents a stable brain activity index during repeated measurement with or without movie-watching. We then assessed the movie-watching-induced regional BEN changes compared to resting state and regional BEN differences between different movie clips. we found higher reliability during movie-watching and movie-watching induced lower BEN in the sensory cortex and higher BEN in the association cortex compared to the resting state. We replicated and validated all findings in test-retest clips. This work systematically evaluated the regional BEN during movie-watching, providing a new direction for exploring brain activity under natural paradigms using BEN.