Spatial navigation

Neurons engage in causal interactions with one another and with the surrounding body and environment. Neural systems can therefore be analyzed in terms of causal networks, without assumptions about information processing, neural coding, and the like. Here, we review a series of studies analyzing causal networks in simulated neural systems using a combination of Granger causality analysis and graph theory. Analysis of a simple targetfixation model shows that causal networks provide intuitive representations of neural dynamics during behavior which can be validated by lesion experiments. Extension of the approach to a neurorobotic model of the hippocampus and surrounding areas identifies shifting causal pathways during learning of a spatial navigation task. Analysis of causal interactions at the population level in the model shows that behavioral learning is accompanied by selection of specific causal pathways-''causal cores''-from among large and variable repertoires of neuronal interactions. Finally, we argue that a causal network perspective may be useful for characterizing the complex neural dynamics underlying consciousness.

By having subjects drive a virtual taxicab through a computer-rendered town, we examined how landmark and layout information interact during spatial navigation. Subject-drivers searched for passengers, and then attempted to take the most eYcient route to the requested destinations (one of several target stores). Experiment 1 demonstrated that subjects rapidly learn to Wnd direct paths from random pickup locations to target stores. Experiment 2 varied the degree to which landmark and layout cues were preserved across two successively learned towns. When spatial layout was preserved, transfer was low if only target stores were altered, and high if both target stores and surrounding buildings were altered, even though in the latter case all local views were changed. This suggests that subjects can rapidly acquire a survey representation based on the spatial layout of the town and independent of local views, but that subjects will rely on local views when present, and are harmed when associations between previously learned landmarks are disrupted. We propose that spatial navigation reXects a ଝ This manuscript was accepted under the editorship of Jacques Mehler. ଝଝ This research was funded by National Institutes of Health Grants MH55687, MH61975 and MH68404. We thank Ben Burack for creating our virtual reality engine and Greg Schwartz for technical assistance with the OpenGL Utility Toolkit libraries.

Down syndrome (DS) is associated with extreme difficulty in verbal skills and relatively better visuo-spatial skills. Indeed, visuo-spatial ability is often considered a strength in DS. However, it is not clear whether this strength is only relative to the poor verbal skills, or, more impressively, relative to cognitive ability in general. To answer this question, we conducted an extensive literature review of studies on visuo-spatial abilities in people with Down syndrome from January 1987 to May 2013. Based on a general taxonomy of spatial abilities patterned after Lohman, Pellegrino, Alderton, and and and existing studies of DS, we included five different domains of spatial abilities -visuo-spatial memory, visuo-spatial construction, mental rotation, closure, and wayfinding. We evaluated a total of 49 studies including 127 different comparisons. Most comparisons involved a group with DS vs. a group with typical development matched on mental age and compared on a task measuring one of the five visuo-spatial abilities. Although further research is needed for firm conclusions on some visuo-spatial abilities, there was no evidence that visuo-spatial ability is a strength in DS relative to general cognitive ability. Rather, the review suggests an uneven profile of visuo-spatial abilities in DS in which some abilities are commensurate with general cognitive ability level, and others are below.

Bat echolocation is an ability consisting of many subtasks such as navigation, prey detection and object recognition. Understanding the echolocation capabilities of bats comes down to isolating the minimal set of acoustic cues needed to complete each task. For some tasks, the minimal cues have already been identified. However, while a number of possible cues have been suggested, little is known about the minimal cues supporting obstacle avoidance in echolocating bats. In this paper, we propose that the Interaural Intensity Difference (IID) and travel time of the first millisecond of the echo train are sufficient cues for obstacle avoidance. We describe a simple control algorithm based on the use of these cues in combination with alternating ear positions modeled after the constant frequency bat Rhinolophus rouxii. Using spatial simulations (2D and 3D), we show that simple phonotaxis can steer a bat clear from obstacles without performing a reconstruction of the 3D layout of the scene. As such, this paper presents the first computationally explicit explanation for obstacle avoidance validated in complex simulated environments. Based on additional simulations modelling the FM bat Phyllostomus discolor, we conjecture that the proposed cues can be exploited by constant frequency (CF) bats and frequency modulated (FM) bats alike. We hypothesize that using a low level yet robust cue for obstacle avoidance allows bats to comply with the hard real-time constraints of this basic behaviour.

to evaluate the range of products currently available • to assess the total experience to date with object-oriented databases (OODBMS) • to compare OO and more conventional approaches with specific emphasis on distributed storage, processing, and maintenance Invitations to the workshop were issued to ten experts in the fields of OO theory, navigable databases, and object-oriented geographic information systems GIS; Caltrans personnel; NCGIA researchers; and other invited participants with knowledge and interest in the topic of the conference. The experts were Fran ois Bancilhon,

Little is known on the role of neuronal structures for spatial navigation. Our goal was to examine how Parkinson's disease (PD) and cerebellar ataxia, as human lesion models of the basal ganglia and cerebellum, affect spatial navigation round a circular walking path, blindfolded. Twelve subjects with idiopathic PD (ON and OFF medication), 8 subjects with cerebellar ataxia and a control group of 20 age-matched healthy subjects participated. All groups performed well when walking around the circle with eyes open. In the eyes-closed condition, control subjects overshot the outlined trajectory but returned to their initial position, thus walking a further distance with eyes closed than with eyes open. When OFF medication, PD subjects navigated a larger radius than controls with eyes closed. When ON levodopa, PD subjects walked a similar distance as controls but with even larger errors in endpoint. Surprisingly, cerebellar patients navigated the circular walking task in the eyes closed condition with even more accuracy (i.e. following the outlined circle) than control and PD subjects. We conclude that blindfolded navigation around a previously seen circle requires intact basal ganglia, but not cerebellar input.

Actor-critic algorithms for reinforcement learning are achieving renewed popularity due to their good convergence properties in situations where other approaches often fail (e.g., when function approximation is involved). Interestingly, there is growing evidence that actor-critic approaches based on phasic dopamine signals play a key role in biological learning through cortical and basal ganglia loops. We derive a temporal difference based actor critic learning algorithm, for which convergence can be proved without assuming widely separated time scales for the actor and the critic. The approach is demonstrated by applying it to networks of spiking neurons. The established relation between phasic dopamine and the temporal difference signal lends support to the biological relevance of such algorithms.

We present a novel Bayesian approach to the problem of value function estimation in continuous state spaces. We define a probabilistic generative model for the value function by imposing a Gaussian prior over value functions and assuming a Gaussian noise model. Due to the Gaussian nature of the random processes involved, the posterior distribution of the value function is also Gaussian and is therefore described entirely by its mean and covariance. We derive exact expressions for the posterior process moments, and utilizing an efficient sequential sparsification method, we describe an on-line algorithm for learning them. We demonstrate the operation of the algorithm on a 2-dimensional continuous spatial navigation domain.

There have been discrepancies reported in visuo-spatial construction ability in children with Autism Spectrum Disorders (ASD), fragile X Syndrome (FXS) and those with a comorbid diagnosis of FXS and ASD (AFXS). This study aimed to provide a better understanding of the visuo-spatial processing styles in these heterogeneous neurodevelopmental disorders. Navon-type tasks were used to assess visuo-spatial construction ability across 5 groups of children: typically developing, FXS, AFXS, ASD children who scored lowmoderate (HFA) and ASD children that scored severe (LFA) on the Childhood Autism Rating Scale (CARS). Analyses of their developmental trajectories compared the performance of these groups. Each group produced their own distinct trajectory. HFA achieved higher scores from an earlier age than the TD group, while the LFA group's performance was driven by a bias in local processing. The FXS performance was normalised by using mental age as a predictor while neither mental nor chronological age predicted the AFXS group performance. This study used the Navon-task paradigm to explore the visuo-spatial construction ability in children with FXS and with ASD, including a novel task that minimised the fine motor demands. The paper presents the results from a large sample in a wide age-range (160 children aged between 3 -18 years). Participants were grouped not only as a function of their neurodevelopmental condition but also in terms of the severity of their symptoms and diagnostic comorbidity, as follows: 1. TD (typically developing children) 2. HF ASD -Mild to moderate symptoms 3. LF ASD -Severe symptoms 4. FXS and 5. Comorbid FXS+ASD (AFXS). An analysis of the developmental trajectories of these groups performance showed not only how the "atypical" groups differed from the typical trajectory but also revealed both intra and inter-group differences for the neuro-developmental conditions. The two ASD groups showed different cognitive processing styles in the tasks, a finding that has implications for the current theories on the integration of information in ASD. The FXS group performed closer to what was expected by their mental age, whereas neither mental age nor chronological age predicted the performance of the FXS+ASD group. These findings provide information about the rate of development and age of onset of these skills, rather than the mere absence or presence of an ability, which is valuable to better understand the cognitive profiles of these two conditions and its implications for intervention.

Psychological skills training (PST) is the systematic acquisition and practice of different psychological techniques to improve cognitive and technical performance. This training consists of three phases: education, skills acquisition and practice. Some of the psychological skills developed in this training include relaxation techniques, focusing and concentration skills, positive 'self-suggestion' and visualisation exercises. Since the middle of the 20th century, PST has been successfully applied by athletes, performing artists, business executives, military personnel and other professionals in high-risk occupations. Research in these areas has demonstrated the breadth and depth of the training's effectiveness. Despite the benefits realised in other professions, medicine has only recently begun to explore certain elements of PST. The present paper reviews the history and evidence behind the concept of PST. In addition, it presents some aspects of PST that have already b...

Neurons engage in causal interactions with one another and with the surrounding body and environment. Neural systems can therefore be analyzed in terms of causal networks, without assumptions about information processing, neural coding, and the like. Here, we review a series of studies analyzing causal networks in simulated neural systems using a combination of Granger causality analysis and graph theory. Analysis of a simple targetfixation model shows that causal networks provide intuitive representations of neural dynamics during behavior which can be validated by lesion experiments. Extension of the approach to a neurorobotic model of the hippocampus and surrounding areas identifies shifting causal pathways during learning of a spatial navigation task. Analysis of causal interactions at the population level in the model shows that behavioral learning is accompanied by selection of specific causal pathways-''causal cores''-from among large and variable repertoires of neuronal interactions. Finally, we argue that a causal network perspective may be useful for characterizing the complex neural dynamics underlying consciousness.

Neurons engage in causal interactions with one another and with the surrounding body and environment. Neural systems can therefore be analyzed in terms of causal networks, without assumptions about information processing, neural coding, and the like. Here, we review a series of studies analyzing causal networks in simulated neural systems using a combination of Granger causality analysis and graph theory. Analysis of a simple targetfixation model shows that causal networks provide intuitive representations of neural dynamics during behavior which can be validated by lesion experiments. Extension of the approach to a neurorobotic model of the hippocampus and surrounding areas identifies shifting causal pathways during learning of a spatial navigation task. Analysis of causal interactions at the population level in the model shows that behavioral learning is accompanied by selection of specific causal pathways-''causal cores''-from among large and variable repertoires of neuronal interactions. Finally, we argue that a causal network perspective may be useful for characterizing the complex neural dynamics underlying consciousness.

For spatial navigation many insects rely on compass information derived from the polarization pattern of the sky. We demonstrate that tethered flying desert locusts (Schistocerca gregaria) show e-vectordependent yaw-torque responses to polarized light presented from above. A slowly rotating polarizer (5.3°s)1) induced periodic changes in yaw torque corresponding to the 180°periodicity of the stimulus. Control experiments with a rotating diffuser, a weak intensity pattern, and a stationary polarizer showed that the response is not induced by intensity gradients in the stimulus. Polarotaxis was abolished after painting the dorsal rim areas of the compound eyes black, but remained unchanged after painting the eyes except the dorsal rim areas. During rotation of the polarizer, two e-vectors (preferred and avoided e-vector) induced no turning responses: they were broadly distributed from 0 to 180°b ut, for a given animal, were perpendicular to each other. The data demonstrate polarization vision in the desert locust, as shown previously for bees, flies, crickets, and ants. Polarized light is perceived through the dorsal rim area of the compound eye, suggesting that polarization vision plays a role in compass navigation of the locust.

For spatial navigation many insects rely on compass information derived from the polarization pattern of the sky. We demonstrate that tethered flying desert locusts (Schistocerca gregaria) show e-vectordependent yaw-torque responses to polarized light presented from above. A slowly rotating polarizer (5.3°s)1) induced periodic changes in yaw torque corresponding to the 180°periodicity of the stimulus. Control experiments with a rotating diffuser, a weak intensity pattern, and a stationary polarizer showed that the response is not induced by intensity gradients in the stimulus. Polarotaxis was abolished after painting the dorsal rim areas of the compound eyes black, but remained unchanged after painting the eyes except the dorsal rim areas. During rotation of the polarizer, two e-vectors (preferred and avoided e-vector) induced no turning responses: they were broadly distributed from 0 to 180°b ut, for a given animal, were perpendicular to each other. The data demonstrate polarization vision in the desert locust, as shown previously for bees, flies, crickets, and ants. Polarized light is perceived through the dorsal rim area of the compound eye, suggesting that polarization vision plays a role in compass navigation of the locust.

Acetylcholine contributes to accurate performance of some navigation, but details of its contribution to the underlying brain signals are not fully understood. Selective damage to medial septal cholinergic neurons generally has little effect on landmark-based navigation, or the underlying neural representations of location and directional heading in visual environments. In contrast, the loss of cholinergic neurons disrupts navigation based on path integration, but no studies have tested whether these path integration deficits are associated with disrupted head direction (HD) cell activity. We therefore evaluated HD cell responses to visual cue rotations in a familiar arena, and during navigation between familiar and novel arenas, following muscarinic receptor blockade with systemic atropine. Atropine treatment reduced the peak firing rate of HD cells, but failed to significantly affect other HD cell firing properties. Atropine also failed to significantly disrupt the dominant landmark control of the HD signal, even though we used a procedure that challenged this landmark control. In contrast, atropine disrupted HD cell stability during navigation between familiar and novel arenas, where path integration normally maintains a consistent HD cell signal across arenas. These results suggest that acetylcholine contributes to path integration, in part, by facilitating the use of idiothetic cues to maintain a consistent representation of directional heading.

The study is focused on the assessment of reorientation skills in a sample of community-dwelling elderly people, manipulating landmarks and geometric (layout) information. A neuropsychological assessment was administered to 286 elderly participants, divided into six groups (healthy controls, HC; four subgroups of participants with mild cognitive impairment, MCI; participants with probable dementia, Prob_D) and tested with the Virtual Reorientation Test (VReoT). VReoT manipulated different spatial cues: geometry and landmarks (proximal and distal). Compared with HC, participants with MCI and Prob_D showed to be impaired in tasks involving geometry, landmarks and a combination of them. Both single and multiple domain impairment in MCI had an impact on reorientation performance. Moreover, VReoT was marginally able to discriminate between amnesic and non-amnesic MCI. The occurrence of getting lost events seemed to be associated to learning of geometric information. The associative stren...

The use of landmarks is central to many navigational strategies. Here we use multivoxel pattern analysis of fMRI data to understand how landmarks are coded in the human brain. Subjects were scanned while viewing the interiors and exteriors of campus buildings. Despite their visual dissimilarity, interiors and exteriors corresponding to the same building elicited similar activity patterns in the parahippocampal place area (PPA), retrosplenial complex (RSC), and occipital place area (OPA), three regions known to respond strongly to scenes and buildings. Generalization across stimuli depended on knowing the correspondences among them in the PPA but not in the other two regions, suggesting that the PPA is the key region involved in learning the different perceptual instantiations of a landmark. In contrast, generalization depended on the ability to freely retrieve information from memory in RSC, and it did not depend on familiarity or cognitive task in OPA. Together, these results sugge...

Axons from the nucleus magnocellularis form a presynaptic map of interaural time differences (ITDs) in the nucleus laminaris (NL). These inputs generate a field potential that varies systematically with recording position and can be used to measure the map of ITDs. In the barn owl, the representation of best ITD shifts with mediolateral position in NL, so as to form continuous, smoothly overlapping maps of ITD with iso-ITD contours that are not parallel to the NL border. Frontal space (0°) is, however, represented throughout and thus overrepresented with respect to the periphery. Measurements of presynaptic conduction delay, combined with a model of delay line conduction velocity, reveal that conduction delays can account for the mediolateral shifts in the map of ITD.

Environmental boundaries play a crucial role in spatial navigation and memory across a wide range of distantly-related species. In rodents, boundary representations have been identified at the single-cell level in the subiculum and entorhinal cortex of the hippocampal formation. While studies of hippocampal function and spatial behavior suggest that similar representations might exist in humans, boundary-related neural activity has not been identified electrophysiologically in humans until now. To address this gap in the literature, we analyzed intracranial recordings from the hippocampal formation of surgical epilepsy patients (of both sexes) while they performed a virtual spatial navigation task and compared the power in three frequency bands (1-4 Hz, 4-10 Hz, 30-90 Hz) for target locations near and far from the environmental boundaries. Our results suggest that encoding locations near boundaries elicited stronger theta oscillations than for target locations near the center of the...

This study aimed to investigate the impacts of nonverbal working memory on the writing skills of Iranian (EFL) deaf learners. To attain the purpose of the study, 15 secondary school deaf learners were selected to participate in this study. They were 8th-grade female students of Golestan Exceptional School aged 13-15. The researcher used a non-verbal memory test and a writing test to collect the required data. The participants were asked to participate in the selected tests. The results revealed that there was a statistically significant relationship between learners' non-verbal working memory and writing tests. The findings, also, demonstrated that there was not any significant difference between the writing skill performance of learners with higher capacities of non-verbal working memory and learners with lower capacities of non-verbal working memory. Therefore, the level of non-verbal working memory did not influence the writing skill. The findings have implications for pedagogy as well as further research.

Navigation in virtual worlds is vital for users to move about effectively, complete objectives, and interact with one another and the environment. The ability to accurately orient oneself within a virtual world is essential for successful engagement in video games, simulations and learning environments. This study investigated the effects of perceived affordances on learned navigation and objective location performance within a virtual world. We hypothesized that such perceived affordances impede the learning of virtual geography by fostering reliance on "artificial" cues instead of real space navigation techniques such as the observation of landmarks, spatial orientation, sense of time and distance travelled. The presence of perceived affordances was not significant in predicting retention accuracy. However, the presence of perceived affordances was a significant predictor of objective location performance.

The temporal context model (TCM Howard & Kahana, 2002) was proposed to describe recency and associative effects observed in episodic recall. Episodic recall depends on an intact medial temporal lobe, a region of the brain that also supports a place code. Howard, Fotedar, Datey, and Hasselmo (2005) demonstrated that the leaky integrator that supports a gradually-changing representation of temporal context in TCM is sufficient to describe properties of cells observed in ventromedial entorhinal cortex during spatial navigation if it is provided with input about the animal's current velocity. This representation of temporal context generates noisy place cells in the open field, unlike the clearly-defined place cells observed in the hippocampus. Here we demonstrate that a reasonably accurate spatial representation can be extracted from temporal context with as few as eight cells, suggesting that the spatial precision observed in the place code in the hippocampus is not inconsistent with input from a representation of temporal-spatial context in entorhinal cortex. It has long been believed that the medial temporal lobe (MTL), including the hippocampus and parahippocampal cortical regions, is involved in episodic recall-memory for specific instances from ones' life (e.g. Nadel & Moscovitch, 1997). It has also been clear from neurophysiological results that the MTL is involved in maintaining a representation of position within an open environment (e.g.

Of mice and men: Building blocks in cognitive mapping. NEUROSCI BIOBEHAV REV XX(X) XXX-XXX-Exploration is the process by which humans and other animals gather spatial information and construct some representation of unfamiliar environments, and then utilize this information for traveling in those environments. This survey presents similarities in the travel paths of rodents and humans, suggesting that these constitute an expression of similar underlying biobehavioral mechanisms. Emphasis is given to exploration in dark or large environments, which one cannot encompass at a glance, necessitating a gradual sector-by-sector exploration. This is compared with exploration of the relatively small laboratory testing environments, where a condensed form of exploration dominates. In both rodents and humans, exploration culminates in free traveling, which is mainly determined by the physical environment. For this phase, some principles of urban design in humans and a reminiscent impact of landmarks in test environments in animals are compared. Finally, it is suggested that animal spatial behavior could provide insights into the way that humans perceive and conceive urban environments, and that spatial cognition in different animals, including humans, rests on an evolutionary analogy (or even homology).

For many insects, the polarization pattern of the blue sky serves as a compass cue for spatial navigation. E -vector orientations are detected by photoreceptors in a dorsal rim area of the eye. Polarized-light signals from both eyes are finally integrated in the central complex, a brain area consisting of two subunits, the protocerebral bridge and the central body. Here we show that a topographic representation of zenithal E -vector orientations underlies the columnar organization of the protocerebral bridge in a locust. The maplike arrangement is highly suited to signal head orientation under the open sky.

We investigated the effects of bed rest (BR) immobilization, with and without computerized cognitive training with virtual spatial navigation task (CCT), on vascular endothelium on older subjects. The effects of 14-day BR immobilization in healthy older males (n=16) of ages 53-65 years on endothelial function were studied using EndoPAT(®), a noninvasive and user-independent method. From the group of 16 older men, 8 randomly received CCT during the BR, using virtual navigation tasks in a virtual environment with joystick device. In all the cases, EndoPAT assessments were done at pre- and post-BR immobilization as well as following 28 days of ambulatory recovery. The EndoPAT index increased from 1.53±0.09 (mean ± standard error of the mean) at baseline to 1.61±0.16 following immobilization (P=0.62) in the group with CCT. The EndoPAT index decreased from 2.06±0.13 (mean ± standard error of the mean) at baseline to 1.70±0.09 at the last day of BR study, day 14 (BR14) (P=0.09) in the con...

Early mathematics achievement is highly predictive of later mathematics performance. Here we investigate the influence of executive function (EF) and spatial skills, two generalizable skills often overlooked in mathematics curricula, on mathematics performance in preschoolers. Children (N = 44) of varying socioeconomic status (SES) levels were assessed at age three on a new assessment of spatial skill (Test of Spatial Assembly, TOSA) and a vocabulary measure (the PPVT-4). The same children were tested at age four on the Beery Test of Visual-Motor Integration (VMI), as well as measures of EF, and mathematics. The TOSA was created specifically as an assessment for 3-year-olds, allowing the investigation of links between spatial, EF, and mathematical skills earlier than previously possible. Results of a hierarchical regression indicate that EF and spatial skills predict 70% of the variance in mathematics performance without an explicit math test, EF is an important predictor of math performance as prior research suggested, and spatial skills uniquely predict 27% of the variance in mathematics skills. Additional research is needed to understand if EF is truly malleable and whether EF and spatial skills may be leveraged to support early mathematics skills, especially for lower-SES children who are already falling behind in these skill areas by ages 3 and 4. These findings indicate that both skills are part of an important foundation for mathematics performance and may represent pathways for improving school readiness for mathematics.

Mental mapping of spaces, and of the possible paths for navigating through these spaces, is essential for the development of efficient orientation and mobility skills. The work reported here is based on the assumption that the supply of appropriate spatial information through compensatory channels (conceptual and perceptual), may contribute to the blind people's spatial performance. We developed a multi-sensory virtual environment simulating real-life spaces. This virtual environment comprises developer / teacher mode and learning mode. The ability to navigate space independently, safely and efficiently is a combined product of motor, sensory and cognitive skills. This ability has direct influence in the individuals' quality of life. Mental mapping of spaces, and of the possible paths for navigating through these spaces, is essential for the development of efficient orientation and mobility skills. Most of the information required for this mental mapping is visual information . Blind people lack this crucial information, thus facing great difficulties (a) in generating efficient mental maps of spaces, and therefore (b) in navigating efficiently within these spaces. A result of this deficit in navigational capability is that many blind people become passive persons, depending on others for continuous aid . More then 30% of the blind do not mobilize independently outdoors . The work reported here is based on the assumption that the supply of appropriate spatial information through compensatory sensorial channels, as an alternative to the (impaired) visual channel, may contribute to the mental mapping of spaces and consequently, to blind people's spatial performance.

The effect of environmental enrichment on normal rats, rats that received hemidecortication at birth, and rats that received hemidecortication when adult was studied in the Morris water task, which is a spatial navigation task requiring the use of distal cues for successful performance. Enrichment was achieved by housing the rats for 90 days in a large outdoor compound that was designed to model a natural environment. Adult hemidecorticated lab-raised rats were severely impaired in the acquisition of the task but neonatally hemidecorticated rats, although also impaired, showed significant sparing. Postsurgical, but not presurgical, enrichment of adult hemidecorticated rats significantly enhanced their recovery. Enrichment had little effect on neonatally decorticated rats or on normal rats. Although there were no gross anatomical changes associated with enrichment, the paradigm provides both a robust phenomena and a cortically dependent task that is ideal for investigating the processes in the remaining intact hemisphere that must support recovery.

Background: Despite decades of research on spatial memory, we know surprisingly little about how the brain guides navigation to goals. While some models argue that vectors are represented for navigational guidance, other models postulate that the future path is computed. Although the hippocampal formation has been implicated in processing spatial goal information, it remains unclear whether this region processes pathor vector-related information. Results: We report neuroimaging data collected from subjects navigating London's Soho district; these data reveal that both the path distance and the Euclidean distance to the goal are encoded by the medial temporal lobe during navigation. While activity in the posterior hippocampus was sensitive to the distance along the path, activity in the entorhinal cortex was correlated with the Euclidean distance component of a vector to the goal. During travel periods, posterior hippocampal activity increased as the path to the goal became longer, but at decision points, activity in this region increased as the path to the goal became closer and more direct. Importantly, sensitivity to the distance was abolished in these brain areas when travel was guided by external cues. Conclusions: The results indicate that the hippocampal formation contains representations of both the Euclidean distance and the path distance to goals during navigation. These findings argue that the hippocampal formation houses a flexible guidance system that changes how it represents distance to the goal depending on the fluctuating demands of navigation.

Spatial cognition is a complex higher function in mammals and is involved in a variety of tasks that can be explored in the laboratory. In this review we will discuss the role of the posterior parietal/anteromedial cortex of rodents, also known as the parietal association cortex, and the hippocampal formation in spatial navigation. We will also discuss other higher associational functions of the posterior parietal/anteromedial cortex as they relate to Dr. Pinto-Hamuy's contribution to understanding behavioral functions.

Migratory birds can navigate over tens of thousands of kilometers with an accuracy unobtainable for human navigators. To do so, they use their brains. In this review, we address how birds sense navigation- and orientation-relevant cues and where in their brains each individual cue is processed. When little is currently known, we make educated predictions as to which brain regions could be involved. We ask where and how multisensory navigational information is integrated and suggest that the hippocampus could interact with structures that represent maps and compass information to compute and constantly control navigational goals and directions. We also suggest that the caudolateral nidopallium could be involved in weighing conflicting pieces of information against each other, making decisions, and helping the animal respond to unexpected situations. Considering the gaps in current knowledge, some of our suggestions may be wrong. However, our main aim is to stimulate further research ...

• The link between navigational abilities and Alzheimerʼs disease has provided an early marker for detection of dementia in at-risk individuals. 1 However, it is unclear whether navigational abilities can be used to detect other neurological and mental disorders. • Previous research has found links between some aspects of navigation and autism spectrum disorders as well as depression. 2,3 • This study examines the relationship between three aspects of navigational ability and behavioral traits associated with various mental disorders.

There is preliminary evidence suggesting that hippocampal functioning is associated with attachment style. However, it is unknown if attachment is also associated with hippocampal-related cognitive function such as spatial learning and recall. This study aims to verify if attachment dimensions are associated with spatial learning and recall. Sixty-five female participants were recruited and were evaluated using the Adult Attachment Scale-R and tested on a virtual maze navigation task (VMT) at one moment (exploratory trial + 3 trials) and 24 h later (3 trials). There was a significant Moment × Trial × Close-Depend interaction for the outcome time, F(2,126) = 3.807, p = 0.025, with post hoc analysis indicating that the High Close-Depend group displayed significant improvements between Trial 1 and Trial 3 in the post-test assessment. Conversely, the Low Close-Depend group displayed significant improvements between Trial 1and Trial 3 but on the pre-test assessment. Furthermore, the Low Close-Depend group presented significant better performance in pre-test Trial 3 in comparison to the High Close-Depend group. Thereby, it seems that low comfort with proximity and trust in others is associated with reduced spatial recall, although spatial learning performance was actually superior in these participants. It is possible that reduced exposure to social interaction and meaningful relationships may be reduced in the Low Close-Depend group, leading to modifications in hippocampal function and, ultimately, reduced spatial recall. Oppositely, participants in the High Close-Depend group may not display typical spatial learning in the proposed task as they are more willing to freely explore the presented environment.

Spatial reasoning, in which a person infers novel spatial relationships based on trained relationships, can be conceptualized as arbitrarily applicable spatial relational responding. Here, we conducted two experiments to develop and validate, for the first time, a laboratory procedure to establish arbitrarily applicable spatial relational responding in adult humans. In Experiment 1, participants were trained on nonarbitrary spatial relational tasks designed to establish contextual cues for left of, right of, above, and below. Contextual cues were then used to train a series of arbitrary spatial relations involving four abstract shapes. Following training in a subset of arbitrary relations (A is left of B, B is above C, C is right of D), subsequent testing examined the emergence of untrained spatial relations (B is right of A, C is below B, D is left of C, D is below A and A is above D). When absent in initial tests, spatial relational responding was facilitated by a remedial training procedure incorporating nonarbitrary relational guidance. Participants showed patterns of spatial relational responding consistent with test relations. In Experiment 2, a variant reversal design yielded predictable, reversed spatial relational responses. Overall, the present procedures represent the first empirical demonstration of arbitrarily applicable spatial relational responding and thus, arguably, the first functional analytic model of spatial reasoning.

Spatial reasoning, where novel spatial relationships are inferred based on trained relationships, can be conceptualized as arbitrarily applicable spatial relational responding. Here, we conducted two experiments to develop and validate, for the first time, a laboratory procedure to establish arbitrarily applicable spatial relational responding in adult humans. In Experiment 1, participants were trained on nonarbitrary spatial relational tasks designed to establish contextual cues for left of, right of, above, and below. Contextual cues were then used to train a series of arbitrary spatial relations involving four abstract shapes. Following training in a subset of arbitrary relations (A is left of B, B is above C, C is right of D), subsequent testing examined the emergence of untrained spatial relations (B is right of A, C is below B, D is left of C, D is below A and A is above D). When absent in initial tests, spatial relational responding was facilitated by a remedial training proc...

It has been suggested that the map-like representations that support human spatial memory are fragmented into sub-maps with local reference frames, rather than being unitary and global. However, the principles underlying the structure of these 'cognitive maps' are not well understood. We propose that the structure of the representations of navigation space arises from clustering within individual psychological spaces, i.e. from a process that groups together objects that are close in these spaces. Building on the ideas of representational geometry and similarity-based representations in cognitive science, we formulate methods for learning dissimilarity functions (metrics) characterizing participants' psychological spaces. We show that these learned metrics, together with a probabilistic model of clustering based on the Bayesian cognition paradigm, allow prediction of participants' cognitive map structures in advance. Apart from insights into spatial representation le...

Spatial memory refers to the part of the memory system that encodes, stores, recognizes and recalls spatial information about the environment and the agent's orientation within it. Such information is required to be able to navigate to goal locations, and is vitally important for any embodied agent, or model thereof, for reaching goals in a spatially extended environment. In this paper, a number of computationally implemented cognitive models of spatial memory are reviewed and compared. Three categories of models are considered: symbolic models, neural network models, and models that are part of a systems-level cognitive architecture. Representative models from each category are described and compared in a number of dimensions along which simulation models can differ (level of modeling, types of representation, structural accuracy, generality and abstraction, environment complexity), including their possible mapping to the underlying neural substrate. Neural mappings are rarely ...

Brain disturbances during development can have a lasting impact on neural function and behavior. Seizures during this critical period are linked to significant long-term consequences such as neurodevelopmental disorders, cognitive impairments, and psychiatric symptoms, resulting in a complex spectrum of multimorbidity. The hippocampus-prefrontal cortex (HPC-PFC) circuit emerges as a potential common link between such disorders. However, the mechanisms underlying these outcomes and how they relate to specific behavioral alterations are unclear. We hypothesized that specific dysfunctions of hippocampal-cortical communication due to early-life seizure would be associated with distinct behavioral alterations observed in adulthood. Here, we performed a multilevel study to investigate behavioral, electrophysiological, histopathological, and neurochemical long-term consequences of early-life Status epilepticus in male rats. We show that adult animals submitted to early-life seizure (ELS) present working memory impairments and sensorimotor disturbances, such as hyperlocomotion, poor sensorimotor gating, and sensitivity to psychostimulants despite not exhibiting neuronal loss. Surprisingly, cognitive deficits were linked to an aberrant increase in the HPC-PFC long-term potentiation (LTP) in a U-shaped manner, while sensorimotor alterations were associated with heightened neuroinflammation, as verified by glial fibrillary acidic protein (GFAP) expression, and altered dopamine neurotransmission. Furthermore, ELS rats displayed impaired HPC-PFC theta-gamma coordination and an abnormal brain state during active behavior resembling rapid eye movement (REM) sleep oscillatory dynamics. Our results point to impaired HPC-PFC functional connectivity as a possible pathophysiological mechanism by which ELS can cause cognitive deficits and psychiatric-like manifestations even without neuronal loss, bearing translational implications for understanding the spectrum of multidimensional developmental disorders linked to early-life seizures.

The Radical Pair Mechanism can help to explain avian orientation and navigation. Some evidence indicates that the intensity of external magnetic fields plays an important role in avian navigation. In this paper, based on a two-stage strategy, we demonstrate that birds could reasonably detect the directions of geomagnetic fields and gradients of these fields using a yield-based chemical compass that is sensitive enough for navigation. Also, we find that the lifetime of entanglement in this proposed compass is angle-dependent and long enough to allow adequate electron transfer between molecules.

We investigated the navigation‐related age effects on learning, proactive interference semantic clustering, recognition hits, and false recognitions in a naturalistic situation using a virtual apartment‐based task. We also examined the neuropsychological correlates (executive functioning [EF] and episodic memory) of navigation‐related age effects on memory. Younger and older adults either actively navigated or passively followed the computer‐guided tour of an apartment. The results indicated that active navigation increased recognition hits compared with passive navigation, but it did not influence other memory measures (learning, proactive interference, and semantic clustering) to a similar extent in either age group. Furthermore, active navigation helped to reduce false recognitions in younger adults but increased those made by older adults. This differential effect of active navigation for younger and older adults was accounted for by EF score. Like for the subject‐performed task...

Linear trend (slope) is important information conveyed by graphs. We investigated how sounds influenced slope detection in a visual search paradigm. Four bar graphs or scatter plots were presented on each trial. Participants looked for a positive-slope or a negative-slope target (in blocked trials), and responded to targets in a go/no-go fashion. For example, in a positive-slopetarget block, the target graph displayed a positive slope while other graphs displayed negative slopes (a go trial), or all graphs displayed negative slopes (a no-go trial). When an ascending or descending sound was presented concurrently, ascending sounds slowed detection of negativeslope targets whereas descending sounds slowed detection of positive-slope targets. The sounds had no effect when they immediately preceded the visual search displays, suggesting that the results were due to crossmodal interaction rather than priming. The sounds also had no effect when targets were words describing slopes, such as "positive," "negative," "increasing," or "decreasing," suggesting that the results were unlikely due to semantic-level interactions. Manipulations of spatiotemporal similarity between sounds and graphs had little effect. These results suggest that ascending and descending sounds influence visual search for slope based on a general association between the direction of auditory pitch-change and visual linear trend.

Safely navigating our environment is crucial to daily living, but the study of locomotor navigational control in relation to the complex interaction of personal and environmental factors is still in its infancy. Work to now has proposed different proactive control variables for collision avoidance based on visual information. Such control has more recently been shown to be specific to personal (e.g., age, neurological diseases) and environmental (e.g., obstacle type) characteristics. Continued study of the complex person-environment interaction is required along with continued theorization on combined proactive and reactive control factors.