Tertiary Sulci and Brain Aging: A Novel Approach to Understanding Cognitive Aging

Poster Session F - Tuesday, April 16, 2024, 8:00 – 10:00 am EDT, Sheraton Hall ABC

Bryan Madero¹ (bmadero@uiowa.edu), Chris Oehler¹, Eliot Hazeltine¹, Michelle Voss¹; ¹Universiy of Iowa

Tertiary Sulci (TS) are small, shallow, cortical features thought to form in late gestation. The number of TS in the middle frontal gyrus (MFG) relates to better executive function (EF) in younger adults, and the presence of the paracingulate TS is associated with reduced dementia risk in older adults. It is unclear however how TS influence cognition as the brain undergoes normal aging decline. We used a task-switch paradigm sensitive to cognitive aging to determine whether the presence of posterior middle frontal sulci explained variance in EF task performance among cognitively normal older adults. We measured mixing and switching costs, which broadly measure working memory and switching respectively. TS were manually traced with the aid of anatomical boundaries derived from a data-driven approach. Participants (n = 40) were first grouped based on number of MFG TS, those with less than two or two or more. Controlling for demographic covariates, we found individuals with more TS in the left hemisphere, compared to less TS, had better performance indicated by lower mixing cost (std.Beta =-0.79, p = .016). Additionally, the number of TS as an ordinal measure was also related to lower mixing cost with benefit for 2 (std.Beta =-0.99, p =.025) and 3 TS (std.Beta =-0.98, p = .045) relative to none. Our results indicate the presence of left, not right, MFG TS relates to better EF in older adults. These results support the potential for TS to improve our ability to account for individual differences in cognitive aging.

Topic Area: EXECUTIVE PROCESSES: Development &aging