Temporal dedifferentiation of neural states with age during naturalistic viewing

While life is experienced continuously, we tend to perceive it as a series of events. At a neural level, this event segmentation process has been linked to changes in neural states. An open question is whether these neural states differ with age. Participants (N = 577) from the CamCAN cohort viewed an 8-min movie during fMRI. A data-driven state segmentation method was used to identify neural state changes. To study the effects of age, participants were sorted into 34 age groups. We show that neural states become significantly longer with increasing age, particularly in visual and ventromedial prefrontal cortices. Perceived event boundaries overlapped with state changes in superior temporal and dorsomedial prefrontal regions, but there was no effect of age on this relationship. Our results suggest reduced temporal differentiation of successive neural states with increasing age. Nevertheless, preserved alignment between neural states and perceived events suggests that coarse event segmentation remains intact.