Neural Representations of Memory Transformation (MEM_TRANS)

Overview

Investigators overarching goal is to provide evidence for the link between altered spatiotemporal (where and when) neural mechanisms and the extent of changed memory maintenance in healthy older adults and to identify potential neural markers of compensatory function (cognitive resource). Investigators preliminary studies suggest that healthy older adults, compared to younger adults, benefit behaviorally from increased coupling between frontal and parietal brain waves when retrieving and updating well-consolidated visuomotor sequence memory via stronger top-down cognitive control of memory maintenance. Thus, Investigators central hypothesis is that the dynamics across cortical and subcortical regions (i.e., spatiotemporal representations) during transitions between different levels of memory stability indicate the efficiency of memory maintenance. The rationale is that while temporal and spatial neural signatures carry distinct mechanistic information, the joint definition of spatial and temporal representations will allow the differentiation of compensatory versus neurodegenerative mechanisms.

To investigate the spatiotemporal neural dynamics during memory maintenance mechanisms, healthy older adults will practice a computer-based online visuomotor sequence learning task over consecutive days until reaching a performance plateau. At the performance plateau, participants will undergo concurrent electroencephalography and magnetic resonance imaging (EEG-fMRI) while being exposed to a behavioral interference intervention to perturb the stability of the previously stored memory trace to extract spatiotemporal neural dynamics during these transitional states. Additionally, participants will undergo an additional brain scan to quantify aging-related neurodegeneration based on grey- and white-matter integrity, cerebral perfusion, and resting-state connectivity. Cognitive functioning and putative confounders of learning and memory will be quantified with standardized assessments. The experimental procedures include an individual number of daily computer-based sessions of task practice at home, and two lab visits including questionnaires, neuropsychological testing, and two MRI brain scans distributed over approximately two weeks.