Sex Differences in Spatial Memory: Comparison of Three Tasks Using the Same Virtual Context

Are there sex differences in spatial reference memory in the Morris water maze? A large-sample experimental study

Sex differences have been found in allocentric spatial learning and memory tasks, with the literature indicating that males outperform females, although this issue is still controversial. This study aimed to explore the behavior of male and female rats during the habituation and learning of a spatial memory task performed in the Morris Water Maze (MWM). The study included a large sample of 89 males and 85 females. We found that females searched slightly faster than males during habituation with a visible platform. During learning, both male and female rats decreased the latency and distance traveled to find the hidden platform over the days, with males outperforming females in the distance traveled. Females swam faster but did not find the platform earlier, suggesting a less directed navigational strategy. Both sexes increased time spent in the target zone over the days, with no sex differences. Although females swam more in the periphery during the first days of the task, both sexes decreased the time spent in this area. Finally, only males increased swimming in the pool's center over the days, spending more time than females in this area across the entire training. In conclusion, we need to register several variables in the MWM and analyze path strategies to obtain more robust results concerning sex differences. Research on spatial learning should include both sexes to achieve a more equitable, representative, and translational science.

Behavioral Disorders of Spatial Cognition in Patients with Mild Cognitive Impairment Due to Alzheimer's Disease (The BDSC-MCI Project): Ecological Validity of the Corsi Learning Suvra-Span Test

BACKGROUND

Spatial navigation deficits are reported as early symptoms of Alzheimer's disease (AD) alongside episodic memory ones. The aim of the present study was to ascertain whether neuropsychological deficits of visuospatial long-term memory can predict behavioral alterations during the navigation of older adults in novel urban environments along the normal aging-dementia continuum of the Alzheimer's type.

METHODS

A total of 24 community-dwelling patients with Mild Cognitive Impairment (MCI) due to AD, 27 individuals with subjective cognitive decline (SCD), and 21 healthy controls were assessed in terms of their sequential egocentric and allocentric navigation abilities by using a modified version of the Detour Navigation Test, and neuropsychologically tested by the Corsi learning suvra-span (CLSS) test. Generalized linear models were adopted to verify whether the scores obtained by the three groups in the CLSS test predicted wrong turns and moments of hesitation during the navigation task, with the results presented as topographical disorientation scores.

RESULTS

Higher scores in the CLSS test predicted fewer wrong turns (b = -0.05; z = -2.91; p = 0.004; net of between-groups differences) and moments of hesitation for patients with MCI due to AD (b = -0.14; z = -2.43; p = 0.015), and individuals with SCD (b = -0.17; z = -3.85; p < 0.001).

CONCLUSIONS

Since the CLSS test has been reported to be a reliable measure of ecological navigational abilities in the progression towards AD dementia, we recommend its use in clinical practice and highlight implications for future research.

Application of Virtual Reality in Spatial Memory

In recent years, virtual reality (VR) has become a widely used tool with a plethora of applications in neuroscience [...].

Virtual reality a technological miracle transforming physical rehabilitation: A scoping review

Physical rehabilitation is evolving day by day. In the same way, simulation in rehabilitation is increasing and has now become a cornerstone for rehabilitation programs. Increase in the number of new protocols, clinical methods, and treatment standardization, virtual reality is appearing as a new medium to deliver the simulation. Virtual reality gives the benefits of forming standardized treatment protocols on demand for various conditions repetitively with a cost-effective delivery system. This was an observational retrospective study. The PubMed database was used to obtain the available material related to virtual reality and rehabilitation and was searched using the same keywords. The articles were then sorted as the subject to the recent decade. The basic information was then obtained, which included timespan, sources of the document, average years of publication, document types we collected, and average citation per year per document. Analysis of the literature that was available online related to virtual reality and rehabilitation between 2011 and 2021 generated a list of 813 documents from 275 sources, of which 810 were from journal articles and 3 were book chapters with an average year of publication of 2.16. The highest number of publications was 480 in 2020, followed by 150 in 2019, 95 in 2018, and 28 in 2017. The annual growth rate percentage of scientific publications was 26.1%. Therefore, more studies should be performed on virtual reality.

Reversal Training Discloses Gender Differences in a Spatial Memory Task in Humans

Over the past few years, spatial memory has been studied using virtual-reality-based tasks. Reversal learning has been widely used in spatial orientation tasks for testing, among other things, new learning and flexibility. By means of a reversal-learning protocol, we assessed spatial memory in men and women. A total of sixty participants (half of them women) performed a task that included two phases: during the acquisition phase, participants were asked to find one or three rewarded positions in the virtual room across ten trials. During the reversal phase, the rewarded boxes were moved to a new position and maintained for four trials. The results showed that men and women differed in the reversal phase, with men outperforming women in high demanding conditions. Dissimilarities in several cognitive abilities between both genders are the base of these differences and are discussed.

Age and sex impact on visuospatial working memory (VSWM), mental rotation, and cognitive strategies during navigation

This study assessed the impact of sex and typical aging on visuospatial working memory (VSWM), mental rotations, and navigational strategies using behavioral information. Fifty healthy participants regrouped in older (OA) and young adults (YA) performed the Walking Corsi test (WalCT) and the Redrawn Mental Rotation Test (MRT) to explore mental rotation abilities. We recorded kinematic data such as locomotion trajectories, and spatial orientations during navigation. We created a new method of data analysis for the WalCT performances and compared it with the classical approach. This original method allowed us to identify cognitive strategies based on errors analysis. Our data suggested that VSWM and mental rotation capacities in locomotion were modulated by age (YA scored higher than OA), and sex (Young Adult Males (YA-M) having higher performance than Young Adult Females (YA-F). We observed a preferential use of cognitive strategies related to sex; YA-F relied more on egocentric strategies whereas YA-M relied more on allocentric strategies. The preferential use of cognitive strategies in the YA group was not observed in the OA group producing more random errors per sequence. The results suggest the effects that age and sex have on VSWM, cognitive strategies, and mental rotation during navigation and highlight the importance of navigational strategies training.

Walking on a minefield: planning, remembering, and avoiding obstacles: preliminary findings

Travel planning (TP) is a kind of planning devoted to spatial orientation that is distinguishable from general planning (GP). It is crucial to reach a destination, since it allows to select the best route according to the environmental features (e.g., the one with little traffic or the safest). TP is also needed to avoid obstacles along the way and to put in place effective strategies to support navigation. TP involves several cognitive processes, such as visuo-spatial and topographic memory as well as other executive functions (i.e., general planning, cognitive flexibility, problem solving, and divergent thinking) and it is affected by internal factors (such as gender, cognitive strategies, age). Here, we focused on the effects of visuo-spatial (VSWM) and topographic (TWM) working memory on TP, using the Minefield Task (MFT), a new tool aimed at testing TP. We tested VSWM, TWM, GP, and TP in 44 college students. First, we checked for gender differences in all the tasks proposed and then assessed the relation among VSWM, TWM, GP, and TP. Results showed that even though gender difference could be found on TWM, GP, and TP, significative correlations emerged among TP, VSWM, and GP as well as a tendency to significance for VSWM and GP in the regression analyses. Though more evidence is needed, these results suggest that when a brand-new route is computed, GP and VSWM can be the most relevant processes, whereas topographic memory was less involved, probably because the MFT does not require to recall a route from memory. The implications of these results in clinical settings are discussed.

Development of Landmark Use for Navigation in Children: Effects of Age, Sex, Working Memory and Landmark Type

The use of landmarks for navigation develops throughout childhood. Here, we examined the developmental trajectory of egocentric and allocentric navigation based on landmark information in an on-screen virtual environment in 39 5–6-year-olds, 43 7–8-year-olds, and 41 9–10-year-olds. We assessed both categorical performance, indicating the notion of location changes based on the landmarks, as well as metrical performance relating to the precision of the representation of the environment. We investigated whether age, sex, spatial working memory, verbal working memory, and verbal production of left and right contributed to the development of navigation skills. In egocentric navigation, Categorical performance was already above chance at 5 years of age and was positively related to visuo-spatial working memory and the production of left/right, whereas metrical performance was only related to age. Allocentric navigation started to develop between 5 and 8 years of age and was related to sex, with boys outperforming girls. Both boys and girls seemed to rely more on directional landmark information as compared to positional landmark information. To our knowledge, this study is the first to give insight into the relative contribution of different cognitive abilities to navigation skills in school-aged children.

Prepubescent female rodents have enhanced hippocampal LTP and learning relative to males, reversing in adulthood as inhibition increases

Multiple studies indicate that adult male rodents perform better than females on spatial problems and have a lower threshold for long-term potentiation (LTP) of hippocampal CA3-to-CA1 synapses. We report here that, in rodents, prepubescent females rapidly encode spatial information and express low-threshold LTP, whereas age-matched males do not. The loss of low-threshold LTP across female puberty was associated with three inter-related changes: increased densities of α5 subunit-containing GABAARs at inhibitory synapses, greater shunting of burst responses used to induce LTP and a reduction of NMDAR-mediated synaptic responses. A negative allosteric modulator of α5-GABAARs increased burst responses to a greater degree in adult than in juvenile females and markedly enhanced both LTP and spatial memory in adults. The reasons for the gain of functions with male puberty do not involve these mechanisms. In all, puberty has opposite consequences for plasticity in the two sexes, albeit through different routes.