The functional architecture of the brain changes considerably across multiple timescales. While the role of variations over long timescales (e.g., years) is widely documented, the functional relevance of microtemporal (i.e., second-level) fluctuations is still debated. Using fMRI data collected during movie watching from two independent samples, we demonstrate that the adaptiveness of variability in functional brain architecture fluctuates across the adult lifespan (18-88 years) due to age-related differences in the associated profiles of network communication. Greater coupling between changes in brain architecture and concrete environmental features is stronger at younger ages and linked to poorer cognitive-affective outcomes. Whole-brain communication pathways anchored in regions key to episodic and semantic context creation contribute to greater brain reconfiguration in response to abstract contextual changes and stronger coupling between changes in brain architecture and concrete environmental features. Our results provide new insights into age-related differences in brain-environment alignment and their relevance to cognitive adaptability and psychopathology.
bioRxiv Subject Collection: Neuroscience