Poster D59, Monday, March 26, 8:00-10:00 am, Exhibit Hall C
I did it my way: Explaining age-related declines in inter-subject synchronization during naturalistic viewing
Karen Campbell1, Cam-CAN2, Linda Geerligs3; 1Brock University, 2Cambridge Centre for Ageing and Neuroscience, University of Cambridge and MRC Cognition and Brain Sciences Unit, 3Donders Institute for Brain, Cognition and Behaviour, Radboud University
When people watch the same naturalistic stimuli (movies), significant inter-subject synchronization (or correlation) between their fMRI timecourses can be observed, not only in primary sensory areas, but also in frontal and parietal regions. We have previously shown that this inter-subject synchronization decreases with age (Campbell et al.,2015-Neurobiol Aging). In the current study, we replicate this effect in a larger sample (N=585) from the Cambridge Centre for Ageing and Neuroscience (www.cam-can.com), and aim to determine its etiology. We show that while synchrony within primary auditory and visual regions is preserved with age, it declines within a number of higher-order regions, mainly the default mode (DMN) and frontoparietal control networks (FPCN). Cluster analyses confirmed that aging is associated with an increase in idiosyncratic (or individualistic) responding to the movie, rather than the emergence of distinct subgroups who respond to the movie in a similar way. Using a sliding window analysis, we show that synchrony within the FPCN and DMN increases throughout the course of the movie and that older adults’ idiosyncratic responding increases over time. Finally, we show that (controlling for age) greater synchrony in the FPCN relates to greater functional connectivity (FC) within and between the FPCN and DAN, while synchrony in the DMN relates to FC within and between the DMN and inferior temporal cortex. Together, these findings suggest that age-related differences in FC may contribute to older adults’ idiosyncratic responding, and this idiosyncratic responding appears to increase over time, possibly reflecting older adults’ diverging interpretations as the narrative progresses.
Topic Area: LONG-TERM MEMORY: Development & aging