Time points or plot points - Are movies processed according to their temporal duration or their underlying content structure?

Movie-watching studies have shown that specific cortical areas are tuned to stimulus segments of certain durations. However, increases in stimulus duration naturally co-occur with increases in content complexity. This study aimed to disentangle the effects of stimulus content and duration to determine whether hierarchically nested, complex, naturalistic stimuli, like movies, are processed primarily on the basis of their underlying temporal or content structure. To this end, 48 participants watched six equal-length blocks of movie frames presented at a constant frame rate in an fMRI experiment. Frames were extracted from either movie scenes or movie shots (Content Level) and displayed as continuous segments for 4, 12 or 36 s (Duration). We applied inter-subject correlation and three-dimensional linear mixed-effects modeling with crossed random effects to identify cortical areas selectively modulated by Content Level and Duration. Effects along the visual processing hierarchy were additionally assessed in a ROI analysis. Whole-brain results were located predominately within distinct subnetworks of the scene network: Movie scenes, compared to shots, elicited stronger engagement in the visually-attuned posterior subnetwork containing the occipital and posterior parahippocampal place areas. Longer stimuli whereas additionally engaged the memory-related anterior scene network including the anterior parahippocampal place area, retrosplenial cortex, and caudal inferior parietal lobe. ROI analyses confirmed that temporally extended, content-rich stimuli preferentially engaged hierarchically higher areas. Overall, these findings support a functional differentiation within the scene network while expanding on its relation to temporal receptive windows, demonstrating that Content Level and Duration interact in shaping the cortical processing of naturalistic movie stimuli.