Aging and spatial cues influence the updating of navigational memories

Maayan Merhav,Thomas Wolbers

doi:10.1038/s41598-019-47971-2

Abstract

Updating navigational memories is important for everyday tasks. It was recently found that older adults are impaired in updating spatial representations in small, bi-dimensional layouts. Because performance in small-scale areas cannot predict navigational behavior, we investigated how aging affects the updating of navigational memories encoded in large, 3-dimensional environments. Moreover, since locations can be encoded relative to the observer (egocentric encoding) or relative to landmarks (allocentric encoding), we tested whether the presumed age-related spatial updating deficit depends on the available spatial cues. By combining whole-body motion tracking with immersive virtual reality, we could dissociate egocentric and allocentric spatial cues and assess navigational memory under ecologically valid conditions (i.e., providing body-based and visual cues). In the task, objects were relocated overnight, and young and older participants had to navigate to the updated locations of the objects. In addition to replicating age-related deficits in allocentric memory, we found age-related impairments in updating navigational memories following egocentric encoding. Finally, older participants depicted stronger representations of the previous navigational context that were correlated with their spatial updating deficits. Given that these effects may stem from inefficient suppression of former navigational memories, our findings propose a mechanism that helps explain the navigational decline in aging.

Highlights

Updating navigational memories is important for everyday tasks
The aims of experiment 1 were to test whether the ability to update long-term, navigational memories is impaired in older adults and to explore the effect of different spatial cues on spatial updating abilities
The analyses revealed positive correlations between the spatial updating deficit and the relative proximity to the original locations, in both the egocentric and allocentric conditions (r = 0.437, n = 27, p = 0.023 and r = 0.49, n = 32, p = 0.004, respectively), suggesting that traces of spatial representations from the original navigational context can hinder the updating of navigational memories (Fig. 4B)

Summary

Introduction

It was recently found that older adults are impaired in updating spatial representations in small, bi-dimensional layouts. Since locations can be encoded relative to the observer (egocentric encoding) or relative to landmarks (allocentric encoding), we tested whether the presumed age-related spatial updating deficit depends on the available spatial cues. Recent findings have demonstrated age-related deficits in the ability to update long-term, spatial representations on a small-scale, bi-dimensional layout[10]. Spatial processing of small, bi-dimensional layouts is not identical to navigation in real environments, because the latter involves bodily movements of the observer, perception of 3D spatial information, etc.[11] It remains to be determined whether older adults are impaired in updating long-term, navigational memories. We aimed to determine whether the type of spatial encoding modulates the presumed age-related deficit in spatial updating

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