Context reactivation in CA1 is linked to age differences in memory for object-context associations

Poster Session B - Sunday, April 14, 2024, 8:00 – 10:00 am EDT, Sheraton Hall ABC

Ms Anna E Karlsson^1,2 (karlsson@mpib-berlin.mpg.de), Ms Claire Pauley², Ms Myriam C Sander²; ¹Humboldt Univ., Berlin, ²MPIB, Berlin

Associative memory decline is typical for normal aging and proposed to depend on impaired binding of information in memory. Accordingly, the hippocampus has been linked to age differences in associative memory. However, its different subfields supports distinct functions in service of memory, and it’s unknown how they contribute differently to age related declines in associative memory. To assess this, we had older and younger adults perform an associative memory task where they associated objects with a scene image serving as context. Before and after learning, participants viewed the objects and scenes individually, while performing a cover task in the scanner. Finally, their memory for objects and object-scene pairs were tested behaviorally. To investigate age differences in spontaneous context reactivation following learning, we computed representational similarity between objects in the post-learning scan and their associated scenes in the pre-learning scan. We hypothesized objects subsequently remembered and accompanied by correct pair memory to show stronger context reactivation relative to objects later remembered but accompanied by incorrect pair memory. Reduced pair memory performance in older adults were accompanied by reduced context reactivation in CA1 relative to the younger adults. Interestingly, single-trial fluctuations in context reactivation predicted later pair memory performance in younger adults only. Furthermore, inter-individual differences in context reactivation correlated with inter-individual differences in pair memory performance across both age groups. These results were unique to CA1, implicating its role in representing contextual information bound in memory. Crucially, age related declines in associative memory may be driven by changes in CA1 function.

Topic Area: LONG-TERM MEMORY: Development & aging