Gonadal steroid effects during puberty are often hypothesized to account for the male advantage seen in certain spatial tasks. One spatial task where males consistently show better performance than ...females is the Morris Water Task in which subjects must navigate to a goal location in a pool. We examined whether sex differences exist in pre-pubertal children completing a Virtual Morris Water Task, which has previously shown strong sex differences in adults. Pre-pubertal boys show superior performance to similar-aged girls, as evidenced by shorter latencies to find the platform and stronger preferences for the platform location during a probe trial. These results suggest that sex differences in spatial learning and memory exist prior to puberty and do not appear to require the effects of sex hormones at puberty. Rather, these differences may reflect early-life hormonal effects on hippocampal-dependent processes and may suggest different preferential learning strategies by boys and girls.
The hippocampus has long been implicated in spatial memory, from work in rodents to imaging and brain lesion studies in humans. However, recent evidence has pointed to the recruitment of areas ...outside the hippocampus proper on spatial memory tasks, including the parahippocampal gyrus and precuneus, possibly suggesting a more focused role for the hippocampus proper. In this study, a virtual version of the standard rodent spatial memory assessment, the Morris water task, has been employed during fMRI to investigate the differential involvement of these distinct brain areas. Twenty-eight healthy participants completed a block designed version of the virtual Morris water task (vMWT) which consisted of three conditions: (1) a hippocampal dependent condition during which the participants were forced to use distal room cues in the virtual environment to navigate to a hidden platform; (2) a non-hippocampal dependent condition during which participants were to navigate to a visible platform; (3) a fixation period. Activations of the BOLD signal were evident in the hidden condition as compared to the visible condition in the parahippocampal gyrus, precuneus, and fusiform when analyzed using to a blocked analysis. Moreover, this blocked analysis revealed increases in the right hippocampal BOLD signal during fixation. However, when hidden trials were compared to visible trials using a post hoc event-related analysis focused on the beginning of each trial, activations of the right hippocampus are evident. These results support the theory that extra-hippocampal structures contribute to spatial memory behavior and identify a temporally specific involvement of the hippocampus. Furthermore, they substantiate previous results reporting hippocampal BOLD increases during fixation.
Many contextual factors can influence evacuees' choice of egress route during an emergency. Anxiety caused by the emergency situation may lead to suboptimal choices, resulting in slower evacuation ...and greater risk of injury or death. The present pilot study tests the influence of hazard level (presence of visible fire and smoke) and information about an obstacle (delivered verbally or through signage) on evacuees' anxiety levels and choice of egress route in a virtual reality (VR) simulation of a fire evacuation with multiple possible exits. Physiological measures were recorded and used to validate the efficacy of VR in inducing anxiety germane to the situation of interest. Consistent with our expectations, providing information about the obstacle was shown to decrease total evacuation time. Contrary to our predictions, it did not significantly impact evacuees' choice of exit. Information also had a marginally significant effect on participants' self-reported anxiety. Providing more targeted information may further reduce anxiety and evacuation time. More generally, VR appears well-suited to assessing individual and psychological factors in evacuations.
•Virtual reality simulation of fire emergency in building with multiple exits.•Providing information about an obstacle reduced evacuation time.•Physiological measures show VR efficacy in inducing anxiety.•Evacuation time positively correlated with evacuee anxiety.•High hazard level, utilizing main exits associated with competitive behavior.
In many mammalian species, it is known that males and females differ in place learning ability. The performance by men and women is commonly reported to also differ, despite a large amount of ...variability and ambiguity in measuring spatial abilities. In the non-human literature, the gold standard for measuring place learning ability in mammals is the Morris water task. This task requires subjects to use the spatial arrangement of cues outside of a circular pool to swim to a hidden goal platform located in a fixed location. We used a computerized version of the Morris water task to assess whether this task will generalize into the human domain and to examine whether sex differences exist in this domain of topographical learning and memory. Across three separate experiments, varying in attempts to maximize spatial performance, we consistently found males navigate to the hidden platform better than females across a variety of measures. The effect sizes of these differences are some of the largest ever reported and are robust and replicable across experiments. These results are the first to demonstrate the effectiveness and utility of the virtual Morris water task for humans and show a robust sex difference in virtual place learning.
Different tasks are often used to assess spatial memory in humans compared to nonhumans. In order to bridge this paradigmatic gap, we used a within-subject design to test 61 undergraduates on three ...spatial memory tasks. One of these tasks, the Vanderberg 3D mental rotation task, is classically used to assess spatial memory in humans. The other two tests are virtual analogues of two tasks used classically to assess spatial memory in rodents: the Morris water task and an eight-arm radial maze. We find that males perform significantly better than females on the mental rotation task and in finding a hidden platform in the virtual Morris water task. Moreover, during a probe trial, males spend significantly more distance of their swim in the training quadrant, but males and females do not differ in navigating to a visible platform. However, for the virtual eight-arm radial maze, there is no sex difference in working memory errors, reference memory errors, or distance to find the rewards. Surprisingly, an examination of the correlations among the three tasks indicates that only mental rotation ability and Morris water task probe trial performance correlate significantly among the three tasks (i.e. there are no significant correlations with traditional measures the tasks, e.g. time or distance to completion). Hence, the Morris water task and the eight-arm radial maze do not assess spatial memory in the same manner, and even after equating factors such as motivation, stress, and motor demands, there still are procedural demands of the tasks that reinforce differential strategy selection during spatial memory. This suggests that caution should be taken when utilizing these two tasks interchangeable as tests of spatial memory.
For nonhumans, it has been shown that the hippocampus (HPC) is critical for spatial memory. We tested patients with unilateral HPC resections on a virtual analogue of a classic spatial task to assess ...HPC functioning in nonhumans: the Morris water task. We found that when humans are required to use spatial cues to navigate to a hidden escape platform in a pool, patients with HPC resections display severe impairments in spatial navigation relative to age-matched controls and age-matched patients who have had extra-HPC resections. This effect occurred for every patient tested and was evident regardless of side of surgery. Hence, it is apparent across species and irrespective of which hemisphere is damaged that the human HPC is critical for spatial/relational memory.
The present study examined sex differences in object memory by using 2-dimensional object arrays and in spatial memory by using a computerized virtual 12-arm radial maze. Virtual
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-maze and water ...maze tasks were also used to examine sex differences in the use of spatial and nonspatial strategies during navigation. Women significantly outperformed men in recalling the locations and identities of objects. However, the sexes did not differ in the commission of working memory and reference memory errors in the radial maze or in the use of particular navigational strategies. Because arms in the radial maze may become associated with specific extramaze cues, the superior object memory demonstrated by women may have eliminated the typical male advantage found in spatial navigation tasks.
Using a within-subjects design, rats were trained on two place-memory problems and five object-discrimination problems at different intervals prior to receiving either ibotenate lesions of the ...hippocampal formation or sham surgery. Places #1 and 2 were fixed-platform water-maze tasks that were run in different rooms and they were learned during the 14th and 2nd week before surgery, respectively. Object-discrimination problems #1–5 were learned during the 13th, 10th, 7th, 4th, and 1st week before surgery, respectively. Rats with hippocampal lesions displayed impaired retention of both Place problems with no evidence of a temporal gradient to the impairment. In contrast to their retrograde place-memory deficits, the hippocampal rats displayed normal retention of the five object-discriminations that were learned before surgery. Hippocampal lesions had similar consequences for anterograde learning, as the lesioned rats were impaired in acquisition of a new water-maze problem that was run in a third room (Place #3), whereas they showed normal acquisition of two new object-discriminations. The findings indicate that the hippocampal formation is not required for long-term consolidation of information underlying accurate performance of object-discriminations, and that its critical role in memory for places persists for at least 14 weeks, and probably for as long as those memories exist.
Mass shooting events threaten people's safety with growing frequency and casualties. However, occupants may have difficulties behaving properly for survival because of a lack of information. Although ...gunfire locations and emergency guidance can be provided to occupants by technological advances, the effects of providing such information and guidance are unclear because occupants' survival-related behaviors are complicated and might be influenced by social cues and other factors. In this paper, the effects of providing the information and guidance on occupants' survivability are studied in a virtual reality experiment, and it is found that participants were more likely to survive if information about a shooter's gunfire location was provided than not. To obtain generalizable findings, participants' behavior of looking for the shooter is identified by examining their visual information, and results show that providing the information could shorten the time length of looking at the shooter. However, it remains to be determined how participants utilized the information about shooter's positions to select a safe route. This was addressed by testing different hypotheses through contrasting the goodness of fit for each hypothesized model. The results suggest that participants tend to predict the shooter's movement with the information they perceived. Furthermore, it is revealed that social influences affected participants who might follow others and collide with them, and such influences were weakened by providing information. These results suggest that providing gunfire locations can indeed improve occupants' survivability, comparing to the case with no information provided.
•The effects of providing gunfire locations and guidance are studied.•Providing gunfire locations improves occupants' survivability.•Occupants predict a shooter's movement with the provided information.•Social influences are weakened by providing gunfire locations and guidance.
The use of virtual reality in the form of simulated tasks can provide a realistic environment in which to study complex naturalistic behaviors. Many of the behavioral effects of alcohol intoxication ...are well known, but there is relatively little imaging evidence examining how alcohol exposure might transiently modulate brain function, especially in the context of task performance. In this review, we provide a brief synopsis of previous work using functional magnetic resonance imaging (fMRI) to study the neural correlates of alcohol intoxication. We describe in detail two studies from our published work, the first involving a visual perception paradigm, and the second involving virtual reality through a naturalistic behavior; simulated driving. Participants received single-blind individualized doses of beverage alcohol designed to produce blood alcohol content (BAC) of 0.04 and 0.08 or placebo. Subjects were fMRI scanned after training to asymptote performance. In both studies we found specific circuits that were differentially modulated by alcohol, we revealed both global and local effects of alcohol, and we examined relationships between behavior, brain function, and alcohol blood levels.
