Modularity and development: the case of spatial reorientation

Distinct neural mechanisms for heading retrieval and context recognition in the hippocampus during spatial reorientation

Reorientation, the process of regaining one's bearings after becoming lost, requires identification of a spatial context (context recognition) and recovery of facing direction within that context (heading retrieval). We previously showed that these processes rely on the use of features and geometry, respectively. Here, we examine reorientation behavior in a task that creates contextual ambiguity over a long timescale to demonstrate that male mice learn to combine both featural and geometric cues to recover heading. At the neural level, most CA1 neurons persistently align to geometry, and this alignment predicts heading behavior. However, a small subset of cells remaps coherently in a context-sensitive manner, which serves to predict context. Efficient heading retrieval and context recognition correlate with rate changes reflecting integration of featural and geometric information in the active ensemble. These data illustrate how context recognition and heading retrieval are coded in CA1 and how these processes change with experience.

Language is primarily a tool for communication rather than thought

Language is a defining characteristic of our species, but the function, or functions, that it serves has been debated for centuries. Here we bring recent evidence from neuroscience and allied disciplines to argue that in modern humans, language is a tool for communication, contrary to a prominent view that we use language for thinking. We begin by introducing the brain network that supports linguistic ability in humans. We then review evidence for a double dissociation between language and thought, and discuss several properties of language that suggest that it is optimized for communication. We conclude that although the emergence of language has unquestionably transformed human culture, language does not appear to be a prerequisite for complex thought, including symbolic thought. Instead, language is a powerful tool for the transmission of cultural knowledge; it plausibly co-evolved with our thinking and reasoning capacities, and only reflects, rather than gives rise to, the signature sophistication of human cognition.

Visual boundary cues suffice to anchor place and grid cells in virtual reality

The hippocampal formation contains neurons responsive to an animal's current location and orientation, which together provide the organism with a neural map of space.1,2,3 Spatially tuned neurons rely on external landmark cues and internally generated movement information to estimate position.4,5 An important class of landmark cue are the boundaries delimiting an environment, which can define place cell field position6,7 and stabilize grid cell firing.8 However, the precise nature of the sensory information used to detect boundaries remains unknown. We used 2-dimensional virtual reality (VR)9 to show that visual cues from elevated walls surrounding the environment are both sufficient and necessary to stabilize place and grid cell responses in VR, when only visual and self-motion cues are available. By contrast, flat boundaries formed by the edges of a textured floor did not stabilize place and grid cells, indicating only specific forms of visual boundary stabilize hippocampal spatial firing. Unstable grid cells retain internally coherent, hexagonally arranged firing fields, but these fields "drift" with respect to the virtual environment over periods >5 s. Optic flow from a virtual floor does not slow drift dynamics, emphasizing the importance of boundary-related visual information. Surprisingly, place fields are more stable close to boundaries even with floor and wall cues removed, suggesting invisible boundaries are inferred using the motion of a discrete, separate cue (a beacon signaling reward location). Subsets of place cells show allocentric directional tuning toward the beacon, with strength of tuning correlating with place field stability when boundaries are removed.

What have we learned from research on the "geometric module"?

This article is an overview of the research and controversy initiated by Cheng's (Cognition, 23(2), 149-178, 1986) article hypothesizing a purely geometric module in spatial representation. Hundreds of experiments later, we know much more about spatial behavior across a very wide array of species, ages, and kinds of conditions, but there is still no consensus model of the phenomena. I argue for an adaptive combination approach that entails several principles: (1) a focus on ecological niches and the spatial information they offer; (2) an approach to development that is experience-expectant: (3) continued plasticity as environmental conditions change; (4) language as one of many cognitive tools that can support spatial behavior.

Précis of What Babies Know

Where does human knowledge begin? Research on human infants, children, adults, and nonhuman animals, using diverse methods from the cognitive, brain, and computational sciences, provides evidence for six early emerging, domain-specific systems of core knowledge. These automatic, unconscious systems are situated between perceptual systems and systems of explicit concepts and beliefs. They emerge early in infancy, guide children's learning, and function throughout life.

A cross-cultural study of language and cognition: Numeral classifiers and solid object categorization

One of the central issues in cognition is identifying universal and culturally specific patterns of thought. In this study, we examined how one aspect of culture, a linguistic part of speech known asclassifiers, are related to categorization of solid objects. In Experiment 1, we used a numeral classifier elicitation task to examine the classifiers used by speakers of Hmong, Japanese, and Mandarin Chinese (N = 34) with 135 nouns that referred to solid objects. In Experiment 2, adult speakers of English, Japanese, Mandarin Chinese, and Hmong (N = 64) rated the similarity of 39 pictured objects that depicted a subset of the nouns. All groups classified the objects into natural kinds and artifacts, with the category of humans anchoring both divisions. The main difference that emerged from the study was that speakers of Japanese and English rated humans and animals as more similar to each other than Hmong speakers; Mandarin speakers' ratings of the similarity between humans and animals fell in between those of Hmong and English speakers. However, the pattern of categorization of humans and animals found among speakers of the classifier languages contradicted their patterns of classifier use. The findings help to tease apart the effects of language from other cultural factors that impact cognition.

Two Are Better Than One: Integrating Spatial Geometry with a Conspicuous Landmark in Zebrafish Reorientation Behavior

Within bounded environments of a distinctive shape, zebrafish locate two geometrically equivalent corner positions, based on surface metrics and left-right directions. For instance, the corners with a short surface right/long surface left cannot be distinguished as unique spatial locations unless other cues break the symmetry. By conjoining geometry with a conspicuous landmark, such as a different-color surface, one of the two geometric twins will have a short different-colored surface right, becoming identifiable. Zebrafish spontaneously combine a rectangular white arena's shape with a blue wall landmark, but only when this landmark is near the target corner; when far, that cue triggers a steady attractiveness bias. In this study, we trained zebrafish to use a blue wall landmark in conjunction with a rectangular-shaped arena, providing them rewards over time. We found that trained zebrafish learned to locate the target corner, regardless of the landmark's length and distance, overcoming the attractiveness bias. Zebrafish preferred geometry after removing the landmark (geometric test), but not if put into conflict geometry and landmark (affine transformation). Analysis on movement patterns revealed wall-following exploration as a consistent strategy for approaching the target corner, with individual left-right direction. The capacity of zebrafish to handle different sources of information may be grounds for investigating how environmental changes affect fish spatial behavior in threatened ecosystems.

Navigational roots of spatial and temporal memory structure

Our minds are constantly in transit, from the present to the past to the future, across places we have and have not directly experienced. Nevertheless, memories of our mental time travel are not organized continuously and are adaptively chunked into contexts and episodes. In this paper, I will review evidence that suggests that spatial boundary representations play a critical role in providing structure to both our spatial and temporal memories. I will illustrate the intimate connection between hippocampal spatial mapping and temporal sequencing of episodic memory to propose that high-level cognitive processes like mental time travel and conceptual mapping are rooted in basic navigational mechanisms that we humans and nonhuman animals share. Our neuroscientific understanding of hippocampal function across species may provide new insight into the origins of even the most uniquely human cognitive abilities.

The Development of Human Navigation in Middle Childhood: A Narrative Review through Methods, Terminology, and Fundamental Stages

Spatial orientation and navigation are fundamental abilities in daily life that develop gradually during childhood, although their development is still not clear. The main aim of the present narrative review was to trace the development of navigational skills in middle childhood (6 to 12 years old) by means of studies present in the literature. To this aim, this review took into account the terminology, methodologies, different paradigms, and apparatuses used to investigate egocentric self-centered and allocentric world-centered representations, besides the different types of spaces (reaching/small/large; physical/virtual). Furthermore, this review provided a brief description of the development of navigational strategies and competences in toddlers and preschool children (0–5 years). The main result of this review showed how middle childhood is a crucial period for the improvement and development of allocentric strategies, including metric information. In fact, during this developmental window, children learn to handle proximal and distal cues, to transpose paper and virtual information into real environments, up to performing similarly to adults. This narrative review could represent a starting point to better clarify the development of navigation and spatial orientation, finalized to trace a development curve useful to map normal development and to have a term of comparison to assess performance in atypical development.

Selective neural coding of object, feature, and geometry spatial cues in humans

Orienting in space requires the processing of visual spatial cues. The dominant hypothesis about the brain structures mediating the coding of spatial cues stipulates the existence of a hippocampal-dependent system for the representation of geometry and a striatal-dependent system for the representation of landmarks. However, this dual-system hypothesis is based on paradigms that presented spatial cues conveying either conflicting or ambiguous spatial information and that used the term landmark to refer to both discrete three-dimensional objects and wall features. Here, we test the hypothesis of complex activation patterns in the hippocampus and the striatum during visual coding. We also postulate that object-based and feature-based navigation are not equivalent instances of landmark-based navigation. We examined how the neural networks associated with geometry-, object-, and feature-based spatial navigation compared with a control condition in a two-choice behavioral paradigm using fMRI. We showed that the hippocampus was involved in all three types of cue-based navigation, whereas the striatum was more strongly recruited in the presence of geometric cues than object or feature cues. We also found that unique, specific neural signatures were associated with each spatial cue. Object-based navigation elicited a widespread pattern of activity in temporal and occipital regions relative to feature-based navigation. These findings extend the current view of a dual, juxtaposed hippocampal-striatal system for visual spatial coding in humans. They also provide novel insights into the neural networks mediating object versus feature spatial coding, suggesting a need to distinguish these two types of landmarks in the context of human navigation.

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.

An adaptive cue selection model of allocentric spatial reorientation

After becoming disoriented, an organism must use the local environment to reorient and recover vectors to important locations. A new theory, adaptive combination, suggests that the information from different spatial cues is combined with Bayesian efficiency during reorientation. To test this further, we modified the standard reorientation paradigm to be more amenable to Bayesian cue combination analyses while still requiring reorientation in an allocentric (i.e., world-based, not egocentric) frame. Twelve adults and 20 children at ages 5 to 7 years old were asked to recall locations in a virtual environment after a disorientation. Results were not consistent with adaptive combination. Instead, they are consistent with the use of the most useful (nearest) single landmark in isolation. We term this adaptive selection. Experiment 2 suggests that adults also use the adaptive selection method when they are not disoriented but are still required to use a local allocentric frame. This suggests that the process of recalling a location in the allocentric frame is typically guided by the single most useful landmark rather than a Bayesian combination of landmarks. These results illustrate that there can be important limits to Bayesian theories of the cognition, particularly for complex tasks such as allocentric recall.

Whether studying the development of children’s spatial cognition, creating artificial intelligence with human-like capacities, or designing civic spaces, we can benefit from a strong understanding of how humans process the space around them. Here we tested a prominent theory that brings together statistical theory and psychological theory (Bayesian models of perception and memory) but found that it could not satisfactorily explain our data. Our findings suggest that when tracking the spatial relations between objects from different viewpoints, rather than efficiently combining all the available landmarks, people often fall back to the much simpler method of tracking the spatial relation to the nearest landmark.

Blindfolded adults' use of geometric cues in haptic-based relocation

Non-visual information is important for navigation in limited visibility conditions. We designed a haptic-based relocation task to examine blindfolded adults' use of geometric cues. Forty-eight participants learned to locate a corner in a parallelogram frame. They were then tested in different transformed frames: (a) a reverse-parallelogram, in which locations predicted by original length information and angle information conflicted, (b) a rectangle, which retained only length information, and (c) a rhombus, which retained only angle information. Results show that access to the environment's geometry through haptic modality is sufficient for relocation. However, adults' performances in the current task were different from that in visual tasks in previous findings. First, compared to previous findings in visual-based tasks, length information lost its priority. Approximately half of the participants relied on angle information in the conflict test and the other half relied on length. Second, though participants encoded both length and angle information in the learning phase, only one cue was relied on after the conflict test. Finally, though participants encoded the target location successfully, they failed to represent the global shape of the environment. We attribute adults' different performances in haptic-based and visual-based tasks to the high cognitive demands in encoding and using haptic spatial cues, especially length information.

Separation of geometric and featural information in children's spatial representation: Evidence from a model selection task

Previous studies in spatial reorientation have found that young children rely mainly on geometric shapes for reorientation and sometimes ignore features in the environment. Theoretical interpretations of children's reorientation performance are usually attributed to children's spatial representation of their surrounding environments. The geometric module theory states that featural information is represented separately from geometric shape in young children's reorientation, whereas the adaptive combination model depicts an integral representation. Reorientation tasks, however, require the recognition of a specific location, and thus how the whole environment is represented remains unknown. The current study, using a model selection task, explored young children's representation of the whole surrounding environment. A total of 75 children aged 3-5 years participated in the study. In each trial, children observed a large enclosure and were then asked to choose the corresponding model from two small models. The geometric shapes of the enclosure (rectangle vs. rhombus) and the types of distractors (shape distraction vs. feature position distraction) varied. Results showed that all three age groups performed above the chance level in the shape distraction conditions. Children had more difficulty with the feature position distraction conditions than with the shape distraction conditions. When the distractor shared the feature but at an inappropriate position, children's performance was significantly poorer, especially in the rhombic enclosure. The results provide evidence that young children may represent featural cues separately from geometric shapes.

An analysis of distinct navigational domains and topographical disorientation syndromes in ABI: A meta-analysis

Topographical disorientation is the impairment or inability to successfully navigate in three-dimensional space. Differing topographical disorientation syndromes have been associated with distinct lesion sites in the acquired brain injury (ABI) literature. This meta-analysis attempted to investigate the relationship between lesion location and dysfunctions in specific navigational abilities resulting in topographical disorientation in individuals with ABI, as measured by their performance on experimental and neuropsychological tests. It was expected that focal lesions would be associated with a specific navigational deficit in one ability, with relative sparing of other navigational abilities. Twenty-six papers met the inclusion criteria for the analysis. Results indicated that ABI populations performed worse on all measures of navigation, with moderate to large effect sizes. Dysfunctions in three core navigational skills were consistent with the available lesion studies: a feature/landmark processing unit, a spatial processing unit, and a spatial/feature binding and associative learning unit. A sequential processing model was created to attempt to best represent the transfer of information between these units and the process by which navigational knowledge is generated. The model was then used to assess the validity of existing models of navigation and topographical disorientation.

Use of features and geometry in leopard geckos (Eublepharis macularius)

All animals must move efficiently throughout their world. However, the mechanisms through which they accomplish this potentially vary among species. Previous work exploring the use of feature information and geometric information in movement through space has indicated that geometric information is commonly used and that some species sometimes also use feature information. Here, I investigated if a cold-blooded species, leopard geckos (Eublepharis macularius), would use geometric and/or feature information. In training, geckos learned to move to a correct corner within the box with a distinctive feature. In test when only geometric information was available, geckos chose either their assigned corner or its geometric opposite. In another test when feature information conflicted with geometric information, geckos did not use feature information and instead made choices consistent with using geometric information. This suggests geckos used geometric information preferentially to feature information in this experiment after both had been available throughout training when they were placed in conflict.

Do Older and Young Adults Learn to Integrate Geometry While Navigating in an Environment of a Serious Game?

We evaluated the outcomes of an intervention using a serious game designed to be played on iPads for improving spatial reorientation by training users to integrate geometry of the environment, instead of relying solely on featural cues. Using data logged online through a clinical study of using this game, the effect of training among 16 older adults (69.3 ± 6.4 years, 4 males), who played the game repeatedly (self-administered) over a period of 8 weeks, was investigated. The game contains a hexagonal room with 3 objects, textured walls, and grids on the floor, which are removed one by one as the participant played the game. In each level, the room also rotates such that the viewpoint of the user is different from that of the previous level. Participants cannot play a higher level unless they make no mistake during the trials of the lower test level. In addition to data of older adults available from that clinical trial, we recruited 16 young adults (27.3 ± 5.6 years, 4 males) to play the game for 5 sessions and compared their results with those of the older adults. We evaluated the error type made in each test level and the scores for each session among older adults. Further, we compared the frequency of each error type between young and older adults during the test levels that a landmark adjacent to the target was removed over the first 5 sessions. The results of older adults’ performance suggest they learned to make fewer mistakes over the sessions. Also, both young and older adults learned to integrate the geometrical cues rather than relying on the landmark cue adjacent to the target to find the target. Overall, the results indicate the designed hexagonal room game can enhance spatial cognition among all age groups of adults.

The influence of yaw rotation on spatial navigation during development

Sensory cues enable navigation through space, as they inform us about movement properties, such as the amount of travelled distance and the heading direction. In this study, we focused on the ability to spatially update one's position when only proprioceptive and vestibular information is available. We aimed to investigate the effect of yaw rotation on path integration across development in the absence of visual feedback. To this end, we utilized the triangle completion task: participants were guided through two legs of a triangle and asked to close the shape by walking along its third imagined leg. To test the influence of yaw rotation across development, we tested children between 6 and 11 years old (y.o.) and adults on their perceptions of angles of different degrees. Our results demonstrated that the amount of turn while executing the angle influences performance at all ages, and in some aspects, also interacted with age. Indeed, whilst adults seemed to adjust their heading towards the end of their walked path, younger children took less advantage of this strategy. The amount of disorientation the path induced also affected participants' full maturational ability to spatially navigate with no visual feedback. Increasing induced disorientation required children to be older to reach adult-level performance. Overall, these results provide novel insights on the maturation of spatial navigation-related processes.

NavWell: A simplified virtual-reality platform for spatial navigation and memory experiments

Being able to navigate, recall important locations, and find the way home are critical skills, essential for survival for both humans and animals. These skills can be examined in the laboratory using the Morris water maze, often considered the gold standard test of animal navigation. In this task, animals are required to locate and recall the location of an escape platform hidden in a pool filled with water. Because animals can not see the platform directly, they must use various landmarks in the environment to escape. With recent advances in technology and virtual reality (VR), many tasks originally used in the animal literature can now be translated for human studies. The virtual water maze task is no exception. However, a number of issues are associated with these mazes, including cost, lack of flexibility, and lack of standardization in terms of experimental designs and procedures. Here we present a virtual water maze system (NavWell) that is readily downloadable and free to use. The system allows for the easy design of experiments and the testing of participants on a desktop computer or fully immersive VR environment. The data from four independent experiments are presented in order to validate the software. From these experiments, a set of procedures for use with a number of well-known memory tests is suggested. This potentially can help with the standardization of navigational research and with navigational testing in the clinic or in an educational environment. Finally, we discuss the limitations of the software and plans for its development and future use.

Uncertainty promotes information-seeking actions, but what information?

Navigating an unfamiliar city almost certainly brings out uncertainty about getting from place to place. This uncertainty, in turn, triggers information gathering. While navigational uncertainty is common, little is known about what type of information people seek when they are uncertain. The primary choices for information types with environments include landmarks (distal or local), landmark configurations (relation between two or more landmarks), and a distinct geometry, at least for some environments. Uncertainty could lead individuals to more likely seek one of these information types. Extant research informs both predictions about and empirical work exploring this question. This review covers relevant cognitive literature and then suggests empirical approaches to better understand information-seeking actions triggered by uncertainty. Notably, we propose that examining continuous navigation data can provide important insights into information seeking. Benefits of continuous data will be elaborated through one paradigm, spatial reorientation, which intentionally induces uncertainty through disorientation and cue conflict. While this and other methods have been used previously, data have primarily reflected only the final choice. Continuous behavior during a task can better reveal the cognition-action loop contributing to spatial learning and decision making.

Young Children's Representation of Locations in a Series: A Front-Back Representation or an Ordinal Representation?

Previous research has found that 3–5-year-old children could encode and retrieve a target location in a two-location series. In a paradigm of running two symmetrical railcars on a circular track, the study suggested that children used front-back array to help coding. That is, children at this age code the railcar running in the front of another as “the location in the front” and the railcar running in the back of another as “the location in the back.” However, the children’s success could be attributed to an alternative interpretation; using an ordinal representation to encode the location in front as the first with the other as the second. The current study used a four-location series to examine the children’s mental representation. Three- to five-year-old children participated in a hide-and-seek game to remember a target location out of four locations that moved in a series. The results showed salient individual differences in children’s representation, and their performance improved as the representation progressed. An ordinal representation supported the precise encoding of each location, while a vague front-back representation and a clearer front-middle-back representation led to different performance.

Mapping Mind-Brain Development: Towards a Comprehensive Theory

The relations between the developing mind and developing brain are explored. We outline a theory of intellectual development postulating that the mind comprises four systems of processes (domain-specific, attention and working memory, reasoning, and cognizance) developing in four cycles (episodic, realistic, rule-based, and principle-based representations, emerging at birth, 2, 6, and 11 years, respectively), with two phases in each. Changes in reasoning relate to processing efficiency in the first phase and working memory in the second phase. Awareness of mental processes is recycled with the changes in each cycle and drives their integration into the representational unit of the next cycle. Brain research shows that each type of processes is served by specialized brain networks. Domain-specific processes are rooted in sensory cortices; working memory processes are mainly rooted in hippocampal, parietal, and prefrontal cortices; abstraction and alignment processes are rooted in parietal, frontal, and prefrontal and medial cortices. Information entering these networks is available to awareness processes. Brain networks change along the four cycles, in precision, connectivity, and brain rhythms. Principles of mind-brain interaction are discussed.

For humans navigating without vision, navigation depends upon the layout of mechanically contacted ground surfaces

Navigation can be haptically guided. In specific, tissue deformations arising from both limb motions during locomotion (i.e., gait patterns) and mechanical interactions between the limbs and the environment can convey information, detected by the haptic perceptual system, about how the body is moving relative to the environment. Here, we test hypotheses concerning the properties of mechanically contacted environments relevant to navigation of this kind. We studied blindfolded participants implicitly learning to perceive their location within environments that were physically encountered via walking on, stepping on, and probing ground surfaces with a cane. Environments were straight-line paths with elevated sections where the path either narrowed or remained the same width. We formed hypotheses concerning how these two environments would affect spatial updating and reorientation processes. In the constant pathwidth environment, homing task accuracy was higher and a manipulation of the elevated surface, to be either unchanged or (unbeknown to participants) shortened, biased the performance. This was consistent with our hypothesis of a metric recalibration scaled to elevated surface extent. In the narrowing pathwidth environment, elevated surface shortening did not bias performance. This supported our hypothesis of positional recalibration resulting from contact with the leading edge of the elevated surface. We discuss why certain environmental properties, such as path-narrowing, have significance for how one becomes implicitly oriented the surrounding environment.

Spatial reorientation with a geometric array of auditory cues

A visuocentric bias has dominated the literature on spatial navigation and reorientation. Studies on visually accessed environments indicate that, during reorientation, human and non-human animals encode the geometric shape of the environment, even if this information is unnecessary and insufficient for the task. In an attempt to extend our limited knowledge on the similarities and differences between visual and non-visual navigation, here we examined whether the same phenomenon would be observed during auditory-guided reorientation. Provided with a rectangular array of four distinct auditory landmarks, blindfolded, sighted participants had to learn the location of a target object situated on a panel of an octagonal arena. Subsequent test trials were administered to understand how the task was acquired. Crucially, in a condition in which the auditory cues were indistinguishable (same sound sample), participants could still identify the correct target location, suggesting that the rectangular array of auditory landmarks was encoded as a geometric configuration. This is the first evidence of incidental encoding of geometric information with auditory cues and, consistent with the theory of functional equivalence, it supports the generalisation of mechanisms of spatial learning across encoding modalities.

Late Development of Navigationally Relevant Motion Processing in the Occipital Place Area

Human adults flawlessly and effortlessly navigate boundaries and obstacles in the immediately visible environment, a process we refer to as "visually guided navigation." Neuroimaging work in adults suggests this ability involves the occipital place area (OPA) [1, 2]-a scene-selective region in the dorsal stream that selectively represents information necessary for visually guided navigation [3-9]. Despite progress in understanding the neural basis of visually guided navigation, however, little is known about how this system develops. Is navigationally relevant information processing present in the first few years of life? Or does this information processing only develop after many years of experience? Although a handful of studies have found selective responses to scenes (relative to objects) in OPA in childhood [10-13], no study has explored how more specific navigationally relevant information processing emerges in this region. Here, we do just that by measuring OPA responses to first-person perspective motion information-a proxy for the visual experience of actually navigating the immediate environment-using fMRI in 5- and 8-year-old children. We found that, although OPA already responded more to scenes than objects by age 5, responses to first-person perspective motion were not yet detectable at this same age and rather only emerged by age 8. This protracted development was specific to first-person perspective motion through scenes, not motion on faces or objects, and was not found in other scene-selective regions (the parahippocampal place area or retrosplenial complex) or a motion-selective region (MT). These findings therefore suggest that navigationally relevant information processing in OPA undergoes prolonged development across childhood.

Visual development

The developing visual brain is an integrated system, linking analysis of the visual input to visuomotor control, visual cognition, and attention. Major points in human visual development are the presence of rudimentary pathways present at birth which can control fixation behavior, with subsequent development of specific functions. These functions include the emergence of cortical selectivity; the integration of local signals to provide global representations of motion, shape, and space; the development of visuomotor modules for eye movements, manual reaching, and locomotion; and the development of distinct attentional systems. Measures of these processes in infancy and early childhood can provide indicators of broader brain development in the at-risk child. A key system in development is the dorsal cortical stream. Measures of global motion processing, visuomotor actions, and attention suggest that this system is particularly vulnerable in children with a wide range of neurodevelopmental disorders. Early disorders of the eye (strabismus, cataract) reveal the level of plasticity in the developing visual system and the ways in which early experience can affect the course of functional development.

Using hippocampal-dependent eyeblink conditioning to predict individual differences in spatial reorientation strategies in 3- to 6-year-olds

The hippocampus is a subcortical structure in the medial temporal lobe involved in cognitive functions such as spatial navigation and reorientation, episodic memory, and associative learning. While much is understood about the role of hippocampal function in learning and memory in adults, less is known about the relations between the hippocampus and the development of these cognitive skills in young children due to the limitations of using standard methods (e.g., MRI) to examine brain structure and function in developing populations. This study used hippocampal-dependent trace eyeblink conditioning (EBC) as a feasible approach to examine individual differences in hippocampal functioning as they relate to spatial reorientation and episodic memory performance in young children. Three- to six-year-old children (N = 50) completed tasks that measured EBC, spatial reorientation, and episodic memory, as well as non-hippocampal-dependent processing speed abilities. Results revealed that when age was held constant, individual differences in EBC performance were significantly related to individual differences in performance on the spatial reorientation test, but not on the episodic memory or processing speed tests. When the relations between hippocampal-dependent EBC and different reorientation strategies were explored, it was found that individual differences in hippocampal function predicted the use of geometric information for reorienting in space as opposed to a combined strategy that uses both geometric information and salient visual cues. The utilization of eyeblink conditioning to examine hippocampal function in young populations and its implications for understanding the dissociation between spatial reorientation and episodic memory development are discussed.

Older Adults Show Less Flexible Spatial Cue Use When Navigating in a Virtual Reality Environment Compared With Younger Adults

Daily life requires accurate navigation, and thus better understanding of aging on navigational abilities is critical. Importantly, the use of spatial properties by older and younger adults remains unclear. During this study, younger and older human adults were presented with a virtual environment in which they had to navigate a series of hallways. The hallways provided 2 general types of spatial information: geometric, which included distance and directional turns along a learned route, and featural, which included landmarks situated along the route. To investigate how participants used these different cue types, geometric and/or landmark information was manipulated during testing trials. Data from 40 younger (20 women) and 40 older (20 women) adults were analyzed. Our findings suggest that (1) both younger and older adults relied mostly on landmarks to find their way, and (2) younger adults were better able to adapt to spatial changes to the environment compared with older adults.

Measuring Spontaneous Focus on Space in Preschool Children

Previous work on children's Spontaneous Focus on Numerosity (SFON) has shown the value of measuring children's spontaneous attention within naturalistic interactions. SFON is the spontaneous tendency to focus attention on, and explicitly enumerate the exact number of, items in a set. This measure predicts later math skills above and beyond general IQ and other cognitive factors such as attention. The utility of SFON suggests that a parallel construct for space is a worthy pursuit; spatial cognition underlies many of our mathematical skills, especially as children are first learning these skills. We developed a measure of children's Spontaneous Focus on Space - the spontaneous tendency to attend to absolute and relative spatial components of the environment - and studied its relation to reasoning about the important spatial-numerical concept of proportions. Fifty-five 3- to 6-year-olds were tested at a local children's museums in New York City. Children participated in tasks designed to measure their spontaneous focus on space and number, and their ability to reason about spatial proportions. Results indicate that as children grow older, their Spontaneous Focus on Space becomes more complete and is positively related to proportional reasoning performance. These findings suggest that spatial awareness is rapidly increasing in the preschool years, alongside numerical awareness and spatial-numerical proportional reasoning.

Young children's representation of geometric relationships between locations in location coding

From an early age, children are able to use surface layout geometry and landmarks to search for a hidden toy when disoriented. Theoretical debate remains regarding whether children represent locations based on the global environment or on local cues. Exploring whether children construct and use the relationships between discrete locations of the global environment can provide direct evidence regarding this issue. We investigated young children's representation of two geometric relationships: diagonal relationships (Experiment 1) and same-side relationships (Experiment 2). Children (4- and 5-year-olds) were tested in a square room with a distinctively colored wall. Children completed two tasks. In a two-location task, children watched two toys hidden in two corners that formed one of the two relationships. After disorientating children, the experimenter uncovered one toy and children searched for the other one (target). In a one-location task, only one toy was hidden. In both experiments, children's performance was better in the two-location task than in the one-location task. Furthermore, accuracy in the two-location task of Experiment 1, in which the two corners formed a diagonal relationship, was higher than that of Experiment 2, in which the two corners formed a same-side relationship and a correct location required the combination of this relationship and landmark. These findings suggest that at least by 4 years of age, children can construct geometric relationships between individual corners in their spatial representation and support the global accounts of young children's location coding.

On the transfer of spatial learning between geometrically different shaped environments in the terrestrial toad, Rhinella arenarum

When trained in a rectangular arena, some research has suggested that rats are guided by local features rather than overall boundary geometry. We explored this hypothesis using the terrestrial toad, Rhinella arenarum, as a comparative contrast. In two experiments, toads were trained to find a water-reward goal location in either a featureless rectangular arena (Experiment 1) or in a rectangular arena with a removable colored feature panel covering one short wall (Experiment 2). After learning to successfully locate the water reward, probe trials were carried out by changing the shape of the arena into a kite form with two 90°-angled corners, and in the case of Experiment 2, also shifting the location of the color panel. The results of Experiment 1 indicated that the toads, in contrast to rats, relied primarily on overall shape or boundary geometry to encode the location of a goal. Under the probe conditions of the altered environmental geometry in Experiment 2, the toads seemed to preferentially choose a corner that was generally correct relative to the feature panel experienced during training. Together, the data of the current study suggest that toads and rats differ in the strategies they employ to represent spatial information available in a rectangular arena. Further, the results support the hypothesis that amphibians and mammals engage different neural mechanisms, perhaps related to different evolutionary selective pressures, for the representation of environmental geometry used for navigation.

The Neurobiology of Mammalian Navigation

Mammals have evolved specialized brain systems to support efficient navigation within diverse habitats and over varied distances, but while navigational strategies and sensory mechanisms vary across species, core spatial components appear to be widely shared. This review presents common elements found in mammalian spatial mapping systems, focusing on the cells in the hippocampal formation representing orientational and locational spatial information, and 'core' mammalian hippocampal circuitry. Mammalian spatial mapping systems make use of both allothetic cues (space-defining cues in the external environment) and idiothetic cues (cues derived from self-motion). As examples of each cue type, we discuss: environmental boundaries, which control both orientational and locational neuronal activity and behaviour; and 'path integration', a process that allows the estimation of linear translation from velocity signals, thought to depend upon grid cells in the entorhinal cortex. Building cognitive maps entails sampling environments: we consider how the mapping system controls exploration to acquire spatial information, and how exploratory strategies may integrate idiothetic with allothetic information. We discuss how 'replay' may act to consolidate spatial maps, and simulate trajectories to aid navigational planning. Finally, we discuss grid cell models of vector navigation.

Age-related preference for geometric spatial cues during real-world navigation

Ageing effects on spatial navigation are characterized mainly in terms of impaired allocentric strategies. However, an alternative hypothesis is that navigation difficulties in aged people are associated with deficits in processing and encoding spatial cues. We tested this hypothesis by studying how geometry and landmark cues control navigation in young and older adults in a real, ecological environment. Recordings of body and gaze dynamics revealed a preference for geometry-based navigation in older adults, and for landmark-based navigation in younger ones. While cue processing was associated with specific fixation patterns, advanced age manifested itself in a longer reorientation time, reflecting an unbalanced exploration-exploitation trade-off in scanning policies. Moreover, a battery of tests revealed a specific cognitive deficit in older adults with geometric preference. These results suggest that allocentric strategy deficits in ageing can result from difficulties related to landmark coding, and predict recovery of allocentric strategies in geometrically polarized environments.

Impaired behavioral and neural representation of scenes in Williams syndrome

Boundaries are crucial to our representation of the geometric shape of scenes, which can be used to reorient in space. Behavioral research has shown that children and adults share exquisite sensitivity to a defining feature of a boundary: its vertical extent. Imaging studies have shown that this boundary property is represented in the parahippocampal place area (PPA) among typically developed (TD) adults. Here, we show that sensitivity to the vertical extent of scene boundaries is impaired at both the behavioral and neural level in people with Williams syndrome (WS), a genetic deficit that results in severely impaired spatial functions. Behavioral reorientation was tested in three boundary conditions: a flat Mat, a 5 cm high Curb, and full Walls. Adults with WS could reorient in a rectangular space defined by Wall boundaries, but not Curb or Mat boundaries. In contrast, TD age-matched controls could reorient by all three boundary types and TD 4-year-olds could reorient by either Wall or Curb boundaries. Using fMRI, we find that the WS behavioral deficit is echoed in their neural representation of boundaries. While TD age-matched controls showed distinct neural responses to scenes depicting Mat, Curb, and Wall boundaries in the PPA, people with WS showed only a distinction between the Wall and Mat or Curb, but no distinction between the Mat and Curb. Taken together, these results reveal a close coupling between the representation of boundaries as they are used in behavioral reorientation and neural encoding, suggesting that damage to this key element of spatial representation may have a genetic foundation.

Effect of room size on geometry and features cue preference during reorientation: Modulating encoding strength or cue weighting

Three experiments investigated how the room size affects preferential use of geometric and non-geometric cues during reorientation inside a room. We hypothesised that room size may affect preferential use of geometric and non-geometric cues by affecting the encoding of the cues (the encoding hypothesis), the retrieval of the cues (the retrieval hypothesis), or both the encoding and retrieval of the cues (the encoding-plus-retrieval hypothesis). In immersive virtual rectangular rooms, participants learned objects' locations with respect to geometric (room shape) and non-geometric cues (features on walls or isolated objects). During the test, participants localised objects with the geometric cue only, non-geometric cues only, or both. The two cues were placed at the original locations or displaced relative to each other (conflicting cues) when both were presented at testing. We manipulated the room size between participants within each experiment. The results showed that the room size affected cue preference using conflicting cues but did not affect response accuracy using single cues at testing. These results support the retrieval hypothesis. The results were discussed in terms of the effects of cue salience and stability on cue interaction in reorientation.

Crossing boundaries: Global reorientation following transfer from the inside to the outside of an arena

In 2 spatial navigation experiments, human participants were asked to find a hidden goal (a WiFi signal) that was located in 1 of the right-angled corners of a kite-shaped (Experiment 1) or a cross-shaped (Experiment 2) virtual environment. Goal location was defined solely with respect to the geometry of the environment. Following this training, in a test conducted in extinction, participants were placed onto the outside of the same environments and asked to locate the WiFi signal. The results of both experiments revealed that participants spent more time searching in regions on the outside of the environments that were closest to where the WiFi signal was located during training. These results are difficult to explain in terms of analyses of spatial navigation and reorientation that emphasize the role of local representational encoding or view matching. Instead, we suggest that these results are better understood in terms of a global representation of the shape of the environment.

Navigation and the developing brain

As babies rapidly acquire motor skills that give them increasingly independent and wide-ranging access to the environment over the first two years of human life, they decrease their reliance on habit systems for spatial localization, switching to their emerging inertial navigation system and to allocentric frameworks. Initial place learning is evident towards the end of the period. From 3 to 10 years, children calibrate their ability to encode various sources of spatial information (inertial information, geometric cues, beacons, proximal landmarks and distal landmarks) and begin to combine cues, both within and across systems. Geometric cues are important, but do not constitute an innate and encapsulated module. In addition, from 3 to 10 years, children build the capacity to think about frames of reference different from their current one (i.e. to perform perspective taking). By around 12 years, we see adult-level performance and adult patterns of individual differences on cognitive mapping tasks requiring the integration of vista views of space into environmental space. These lines of development are continuous rather than stage-like. Spatial development builds on important beginnings in the neural systems of newborns, but changes in experience-expectant ways with motor development, action in the world and success–failure feedback. Human systems for integrating and manipulating spatial information also benefit from symbolic capacities and technological inventions.

Comparative spatial memory and cue use: The contributions of Marcia L. Spetch to the study of small-scale spatial cognition

Dr. Marcia Spetch is a Canadian experimental psychologist who specializes in the study of comparative cognition. Her research over the past four decades has covered many diverse topics, but focused primarily on the comparative study of small-scale spatial cognition, navigation, decision making, and risky choice. Over the course of her career Dr. Spetch has had a profound influence on the study of these topics, and for her work she was named a Fellow of the Association for Psychological Science in 2012, and a Fellow of the Royal Society of Canada in 2017. In this review, I provide a biographical sketch of Dr. Spetch's academic career, and revisit her contributions to the study of small-scale spatial cognition in two broad areas: the use of environmental geometric cues, and how animals cope with cue conflict. The goal of this review is to highlight the contributions of Dr. Spetch, her students, and her collaborators to the field of comparative cognition and the study of small-scale spatial cognition. As such, this review stands to serve as a tribute and testament to Dr. Spetch's scientific legacy.

Thinking outside of the box II: Disrupting the cognitive map

A number of influential spatial learning theories posit that organisms encode a viewpoint independent (i.e. allocentric) representation of the global boundary shape of their environment in order to support spatial reorientation and place learning. In contrast to the trial and error learning mechanisms that support domain-general processes, a representation of the global-shape of the environment is thought to be encoded automatically as part of a cognitive map, and without interference from other spatial cues. To date, however, this core theoretical assumption has not been appropriately examined. This is because previous attempts to address this question have failed to employ tasks that fully dissociate reorientation based on an allocentric representation of global-shape from egocentric reorientation strategies. Here, we address this issue in two experiments. Participants were trained to navigate to a hidden goal on one side of a virtual arena (e.g. the inside) before being required to find the same point on the alternative side (e.g. the outside). At test, performing the correct search behaviour requires an allocentric representation of the global boundary-shape. Using established associative learning procedures of overshadowing and blocking, we find that search behaviour at test is disrupted when participants were able to form landmark-goal associations during training. These results demonstrate that encoding of an allocentric representation of boundary information is susceptible to interference from landmark cues, and is not acquired through special means. Instead, the results suggest that allocentric representations of environmental boundaries are acquired through the same kind of error-correction mechanisms that support domain-general non-spatial learning.

Children and Adults Prefer the Egocentric Representation to the Allocentric Representation

We studied the strategy preference of using the egocentric or the allocentric representation in individuals who have acquired the ability to use both representations. Fifty-seven children aged 5–7 years and 53 adults retrieved toys hidden in one of four identical containers in a square room. We varied the type of spatial representation available in four conditions: (1) only self-motion information (egocentric representation); (2) only external landmark cues (allocentric representation); (3) both self-motion and landmark cues (dual representation); (4) self-motion and landmark cues in conflict (conflict trial). We found that, compared with the allocentric representation, the egocentric representation approached maturity earlier in development and was exploited better in early years. More importantly, in the conflict trials, while both children and adults relied more on egocentric representation, still a small portion of participants chose allocentric representation, especially in the adult group. These results provided evidence that egocentric representation is generally preferred more in both young children and adults.

Human spatial representation: what we cannot learn from the studies of rodent navigation

Studies of human and rodent navigation often reveal a remarkable cross-species similarity between the cognitive and neural mechanisms of navigation. Such cross-species resemblance often overshadows some critical differences between how humans and nonhuman animals navigate. In this review, I propose that a navigation system requires both a storage system (i.e., representing spatial information) and a positioning system (i.e., sensing spatial information) to operate. I then argue that the way humans represent spatial information is different from that inferred from the cellular activity observed during rodent navigation. Such difference spans the whole hierarchy of spatial representation, from representing the structure of an environment to the representation of subregions of an environment, routes and paths, and the distance and direction relative to a goal location. These cross-species inconsistencies suggest that what we learn from rodent navigation does not always transfer to human navigation. Finally, I argue for closing the loop for the dominant, unidirectional animal-to-human approach in navigation research so that insights from behavioral studies of human navigation may also flow back to shed light on the cellular mechanisms of navigation for both humans and other mammals (i.e., a human-to-animal approach).