Brain activity at event boundaries during movie watching in ageing and its association with memory
Poster No:
1083
Submission Type:
Abstract Submission
Authors:
Helena Gellersen1, Yannik Lottes1, Merle Hinz1, David Berron1
Institutions:
1German Center for Neurodegenerative Diseases (DZNE), Magdeburg, Germany
First Author:
Co-Author(s):
Introduction:
The brain organizes the continuous stream of information we experience through a process termed "event segmentation" where the hippocampus and regions in the posterior-medial network (PMN) show increased activity when changes in a narrative occur [1,2]. In younger adults, such a boundary-evoked response observed during movie watching correlates with memory recall for movie content [3,4]. Ageing results in a reduction of these hippocampal boundary responses [5], but whether such changes can explain inter-individual differences in memory performance in older adults is unclear. Prior studies also did not investigate boundary responses outside regions in the PMN to test for content-specific associations between boundary responses and memory performance. Here, we examine this relationship between ageing, event segmentation and memory using functional MRI during naturalistic movie watching.
Methods:
The study included 18 cognitively unimpaired older adults aged 63 to 84 years in the MRI cohort and 33 older and 18 younger adults aged 18 to 35 in the behavioural cohort. The behavioural cohort watched a 12-minute movie while marking event boundaries. The MRI cohort watched the same movie in a 3T scanner without indicating boundaries for more natural viewing conditions. After watching the movie, all participants answered memory questions about event order, perceptual details, actions, characters and locations in the narrative. High- and low-salience event boundaries were defined based on 50% and 30% agreement across participants, respectively. We contrasted brain activity at event boundaries with activity around the middle of an event (6s windows for sufficient separation of events). We conducted a whole-brain voxel-wise analysis (uncorrected p<.001) and a region of interest analysis in native subject space, extracting beta values from MTL (anterior, posterior hippocampus; entorhinal and parahippocampal cortices), posterior-medial parietal regions (precuneus; posterior cingulate) and the visual ventral stream as a control.
Results:
For high-salience boundaries, the whole-brain analysis revealed boundary-related activity in the PMN, including the precuneus and posterior cingulate, retrosplenial, and parahippocampal cortices. Bilateral posterior hippocampal boundary effects were also observed. Anterior hippocampus activity was restricted to the right hemisphere. Ventral temporopolar cortex in the anterior-temporal network and regions in the visual ventral stream also increased their activity at event boundaries. Low-salience boundary responses were only observed in occipital cortex, precuneus, and posterior cingulate, not the hippocampus. Older and younger adults did not differ in terms of the number of boundaries placed but in boundary position (t=3.16, p=.002). Younger adults' responses were less variable and more tightly clustered around boundaries. An ANOVA showed that older adults had poorer memory for information for specific actions (t=-2.18, p=.037), characters (t=-2.35, p=.026) and perceptual details (t=-2.18, p=.037) but not for the general order of events or locations in the narrative. There was no association between the magnitude of neural boundary responses in MTL, parietal PMN, anterior-temporal network or visual ventral stream regions and memory performance.
Conclusions:
The pattern of activation in PMN regions and the hippocampus in older adults aligns with that in younger adults in prior studies, suggesting preserved neural responses to event segmentation [3,4]. Increased hippocampal activity was not seen with low boundary salience, while occipito-parietal activity increases remained. Ageing is associated with more variability in boundary placement and content-specific memory decline with more forgetting of narrative details. Although no relationships were found between boundary-evoked brain activity and memory, this may be due to our relatively small sample size and will be investigated in a larger lifespan cohort going forward.
Learning and Memory:
Long-Term Memory (Episodic and Semantic) 1
Lifespan Development:
Aging
Modeling and Analysis Methods:
Activation (eg. BOLD task-fMRI) 2
Keywords:
Aging
Cognition
FUNCTIONAL MRI
Memory
Other - event boundaries; movie watching; hippocampus
1|2Indicates the priority used for review
Provide references using author date format
2. Ben-Yakov & Henson (2018). JoN, 38(47).
3. Ben-Yakov et al. (2013). JEPG, 142(4).
4. Ben-Yakov & Dudai (2011). J Neurosci, 31(24).
5. Reagh et al. (2020). Nat Comms, 11:3980.