Spatial Navigation and Visuospatial Strategies in Typical and Atypical Aging

Age-related spatial navigation decline is more pronounced in patients with mild cognitive impairment (MCI) and Alzheimer’s disease (AD) dementia. We used a realistic-looking virtual navigation test suite to analyze different aspects of visuospatial processing in typical and atypical aging. A total of 219 older adults were recruited from the Czech Brain Aging Study cohort. Cognitively normal older adults (CN; n = 78), patients with amnestic MCI (n = 75), and those with mild AD dementia (n = 66) underwent three navigational tasks, cognitive assessment, and brain MRI. Route learning and wayfinding/perspective-taking tasks distinguished the groups as performance and learning declined and specific visuospatial strategies were less utilized with increasing cognitive impairment. Increased perspective shift and utilization of non-specific strategies were associated with worse task performance across the groups. Primacy and recency effects were observed across the groups in the route learning and the wayfinding/perspective-taking task, respectively. In addition, a primacy effect was present in the wayfinding/perspective-taking task in the CN older adults. More effective spatial navigation was associated with better memory and executive functions. The results demonstrate that a realistic and ecologically valid spatial navigation test suite can reveal different aspects of visuospatial processing in typical and atypical aging.

Aversive View Memory and Navigational Risk Sensitivity in the Desert Ant, Cataglyphis Velox

Many ant species are able to establish routes between goal locations by learning views of the surrounding visual panorama. Route formation models have, until recently, focused on the use of attractive view memories, which experienced foragers orient towards to return to the nest or known food sites. However, aversive views have recently been uncovered as a key component of route learning. Here, Cataglyphis velox rapidly learned aversive views, when associated with a negative outcome, a period of captivity in brush, triggering an increase in hesitation behavior. These memories were based on the accumulation of experiences over multiple trips with each new experience regulating foragers hesitancy. Foragers were also sensitive to captivity time differences, suggesting they possess some mechanism to quantify duration. Finally, we characterized foragers perception of risky (variable) versus stable aversive outcomes by associating two sites along the homeward route with two distinct schedules, a fixed duration of captivity or a variable captivity duration, with the same mean time over training. Foragers exhibited significantly less hesitation to the risky outcome compared to the fixed, indicating they perceived risky outcomes as less severe. Results align with a logarithmic relationship between captivity duration and hesitation response, suggesting that foragers perception of the aversive stimulus is a logarithm of its actual value. We conclude by characterizing how view memory and risk perception can be executed within the mushroom bodies neural circuitry.

Assessing the Effect of a Visual Navigational System on Route-Learning From an Ecological Perspective

Route-learning, considered from an ecological approach to perception, is posited to involve the detection of information over time that specifies a path from one location to another. The study examines whether the use of a visual navigational system (e.g., GPS) may impede route-learning by drawing attention away from transitions along a path that serve as information for way-finding. Virtual reality (VR) technology used in conjunction with an extensive, detailed environmental simulation was employed to explore this possibility. One group of participants drove a simulated car in VR along a designated path while relying on visual GPS guidance. It was expected that use of the GPS display would draw attention away from temporally continuous path information. A second group initially drove the same route without GPS guidance. Both groups drove the path a second time without navigational assistance. Overall, the percentage of correct actions taken at intersections (transitions) during the second trial were significantly lower for the first group who initially drove the route with visual GPS guidance as compared to those who initially traveled the route without it. The results are consistent with the kind of trade-off that is commonplace when tools are used to mediate and assist skilled action.

EXPRESS: Serial memory for landmarks encountered during route navigation

The present study demonstrates similarities between route learning and classical tests of serial order memory. Here, we investigated serial memory for landmarks in a route learning task, in younger and older adults. We analysed data from a route learning task with 12 landmarks, reported by Hilton et al. (2021). Participants (88 younger and 77 older) learned a route using either a Fixed Learning (3 exposures to the route) or Flexible Learning (repeated exposures until successful navigation was achieved) procedure. Following route learning, participants completed Immediate Free Recall (IFR) and Free Reconstruction of Order (Free RoO) of the landmarks. We show clear acquisition of sequence memory for landmarks for both age groups, with Free RoO producing a bowed serial position curve. IFR produced recency effects but no primacy effects in fixed learning, with recency reduced following flexible learning for both age groups. Younger adults displayed a primacy bias for the first item recalled in both learning conditions, as did the older adults in the flexible learning condition. In contrast, older adults displayed a recency bias in the fixed learning condition. Evidence of contiguity in IFR was present only for younger adults in the flexible learning condition. Findings are broadly consistent with results from typical short-term list learning procedures and support the universality of sequence learning effects, which we demonstrate are generalisable to a navigation context.

Turn-by-turn route guidance does not impair route learning

Turn-by-turn GPS guidance is useful when the navigator is uncertain about the correct route. Although route guidance is convenient, it comes at a spatial cognitive cost. Compared to unguided navigation, route guidance leads to poorer knowledge of the traversed environment. However, past research has not tested the effects of route guidance on route retracing, which is an important learning goal in many situations. Participants drove a pre-defined route in a driving simulator. All participants initially followed turn-by-turn directions twice (Experiment 1) or once (Experiment 2). Those in the Study condition continued to follow route guidance during two subsequent traversals, whereas those in the Test condition relied on memory and received corrective feedback. Following a 48-hour delay, participants completed a final test in which they retraced the route without guidance. Learning condition did not influence final test performance, indicating that route knowledge is unaffected by repeatedly following route guidance.