Oscillatory Mechanisms of Successful Memory Formation in Younger and Older Adults Are Related to Structural Integrity

Abstract

We studied oscillatory mechanisms of successful memory formation in 47 younger and 52 older adults in an intentional associative memory task with cued recall. While older adults showed reduced memory performance, we found subsequent memory effects (SME) in alpha/beta and theta frequency bands in both age groups. Using logistic mixed effect models, we then investigated whether interindividual differences in structural integrity of memory regions that were functionally linked to oscillatory dynamics in previous studies (Hanslmayr et al., 2011) could account for interindividual differences in the strength of the SME. Structural integrity of inferior frontal gyrus (IFG) and hippocampus (HC) was reduced in older adults. SME in the alpha/beta band were indeed modulated by the cortical thickness of inferior frontal gyrus (IFG), in line with its hypothesized role for deep semantic elaboration. Importantly, this structure-function relationship did not differ by age group. However, older adults were more frequently represented among the participants with low cortical thickness and consequently weaker SME in the alpha band. Thus, our results suggest that differences in the structural integrity of the IFG are the basis not only for interindividual, but also for age differences in memory formation.