Utilizing naturalistic virtual environments to assess age-related alterations of attention and episodic memory

Project Abstract/Summary Aging is associated with decline in spatial navigation and episodic memory function. Theoretical models argue that navigation and episodic memory are intricately linked – spatial contexts serve as scaffolds for episodic memory, facilitating the encoding, organization, and retrieval of memories. One set of processes that could contribute to both navigational and episodic memory impairments in aging is diminished attention; reduced attentional control and diminished sustained attention in older adults could lead to poor spatial representation, suboptimal navigational strategies, and subsequent declines in memory. The proposed research program will leverage a series of virtual-reality (VR) spatial navigation paradigms, in combination with behavioral and neural markers of attention, spatial coding, and memory to examine how attentional deficits in aging relate to navigation and episodic memory difficulties. Aim 1 will use a VR spatial navigation task to examine how moment-to-moment selective attention and sustained attention (assessed through eye-tracking and pupillometry) relate to spatial navigation performance in older relative to young adults. Expt 1 will assess both age-related and individual differences in (a) how attention relates to navigation performance, (b) the relative salience of types of spatial cues (distal vs. proximal) that influence navigation strategies, and (c) how attention during initial environment encoding affects the ability to calculate new spatial trajectories following changes in the environment. Aim 2 will investigate how age-related differences in behavioral and neural markers of attention relate to differences in the representation of spatial context and in context-mediated regulation of memory integration and interference. Expt 2 will examine how (a) behavioral measures of attention to spatial context relate to episodic memory, influencing when two overlapping events are discriminated (pattern separation), diminishing interference, and when two overlapping events are integrated, enabling novel inferences. Expt 3 will use fMRI to examine (a) age-related differences in the function of neural systems of attention (e.g., frontoparietal cortical networks, locus coeruleus) and episodic memory (e.g., medial temporal lobe) during spatial navigation and associative encoding, along with concurrent pupillometry to (b) measure how trial-by-trial differences in behavioral markers of sustained attention influence neural representations of spatial context and episodic memory and (c) investigate how age-related differences in interactions between attentional and memory systems influence memory integration and interference. Collectively, these studies will advance and link theories of attention, spatial navigation, and memory to early cognitive, behavioral, and neural changes in aging, and promise to enable future study of how attention, navigation, and memory interactions are affected by disease processes (e.g., Alzheimer’s disease).