Individual differences in functional brain network organization associated with a decision-making exploitation bias in older adults

Poster Session D - Monday, April 15, 2024, 8:00 – 10:00 am EDT, Sheraton Hall ABC

Kayla Williams¹ (kayla.williams@mail.mcgill.ca), Patrick Hewan², Shanny Foo¹, Roel van Dooren³, Colleen Hughes¹, Giulia Baracchini¹, Jennifer Tremblay-Mercier⁴, Judes Poirier⁴, Sylvia Villeneuve⁴, Gary R. Turner², R. Nathan Spreng¹; ¹Montréal Neurological Institute, Department of Neurology and Neurosurgery, McGill University, Montréal, QC, Canada, ²York University, Department of Psychology, Toronto, ON, Canada, ³Institutes of Psychology & Brain and Cognition, Leiden University, The Netherlands, ⁴Douglas Research Centre, Department of Psychiatry, McGill University, Montréal, QC, Canada

The exploration-exploitation (EE) trade-off involves the decision between exploring new sources of reward or exploiting options that have been rewarding in the past. In recent work, we identified a set of brain networks implicated in EE decision-making and hypothesized that age-related changes in the functional connectivity of these networks contributes to an exploitation bias in older adults. To test this hypothesis, we took a multivariate network-level approach to examine the relationship between resting-state functional connectivity (RSFC) fMRI and performance on a foraging-based EE decision-making task in a cohort of older adults (N = 118, mean age = 69.7 years). As predicted, greater exploitation was associated with dedifferentiated and less modular brain networks. Specifically, exploitation was associated with greater RSFC of the visual, somatomotor and dorsal attention networks with the rest of the brain, as well as between-network connectivity of the somatomotor and default networks. These findings align with previous research implicating the functional connections between the visual and dorsal attention networks in the encoding of relevant visuospatial information and optimization of the task strategy. Further, lower modularity of the SMM and default networks, which is typically seen with advancing age, may be indicative of an over-reliance on prior knowledge to guide future behaviours, thereby biasing decision-making towards exploitation. These findings, relating RSFC to performance on a foraging-based EE decision-making task, provides novel evidence linking differences in the functional network architecture of the brain to putative exploitative decision-making biases in older adulthood.

Topic Area: THINKING: Decision making