Map-like Representations Research Articles

An Empirical Study on Pertinent Aspects of Sketch Maps for Navigation

Navigation systems which employ sequence-based directions have been found not effective in facilitating the spatial ability for humans to be aware of themselves in an environment. Traditional maps are found easily conveying the configuration of spatial objects but having difficulty to facilitate the correspondence to spatial objects in the real world. Sketch maps as schematic map-like representations have been suggested being a possible way of achieving goals of facilitating both navigation and spatial awareness. Moreover, sketch maps as externalizations of cognitive maps have been proved as reliable representations for human spatial thinking. In this study, the authors investigate the characteristics of directions given in two different forms: sketch maps and verbal descriptions (turn-by-turn instructions). The investigation addresses three aspects of spatial relations which are orientation, street topology and sequential order and their representations using existing qualitative reasoning calculi. The results of this study demonstrate sketch maps as a better direction-giving method and provide insights of applying sketch-map-like components for navigation.

Hippocampal size predicts rapid learning of a cognitive map in humans

The idea that humans use flexible map-like representations of their environment to guide spatial navigation has a long and controversial history. One reason for this enduring controversy might be that individuals vary considerably in their ability to form and utilize cognitive maps. Here we investigate the behavioral and neuroanatomical signatures of these individual differences. Participants learned an unfamiliar campus environment over a period of three weeks. In their first visit, they learned the position of different buildings along two routes in separate areas of the campus. During the following weeks, they learned these routes for a second and third time, along with two paths that connected both areas of the campus. Behavioral assessments after each learning session indicated that subjects formed a coherent representation of the spatial structure of the entire campus after learning a single connecting path. Volumetric analyses of structural MRI data and voxel-based morphometry (VBM) indicated that the size of the right posterior hippocampus predicted the ability to use this spatial knowledge to make inferences about the relative positions of different buildings on the campus. An inverse relationship between gray matter volume and performance was observed in the caudate. These results suggest that (i) humans can rapidly acquire cognitive maps of large-scale environments and (ii) individual differences in hippocampal anatomy may provide the neuroanatomical substrate for individual differences in the ability to learn and flexibly use these cognitive maps. © 2013 Wiley Periodicals, Inc.

Real-time simulation of large-scale neural architectures for visual features computation based on GPU

The intrinsic parallelism of visual neural architectures based on distributed hierarchical layers is well suited to be implemented on the multi-core architectures of modern graphics cards. The design strategies that allow us to optimally take advantage of such parallelism, in order to efficiently map on GPU the hierarchy of layers and the canonical neural computations, are proposed. Specifically, the advantages of a cortical map-like representation of the data are exploited. Moreover, a GPU implementation of a novel neural architecture for the computation of binocular disparity from stereo image pairs, based on populations of binocular energy neurons, is presented. The implemented neural model achieves good performances in terms of reliability of the disparity estimates and a near real-time execution speed, thus demonstrating the effectiveness of the devised design strategies. The proposed approach is valid in general, since the neural building blocks we implemented are a common basis for the modeling of visual neural functionalities.

The ability of young Korean children to use spatial representations

The National Research Council emphasizes using tools of representation as an essential element of spatial thinking. However, it is debatable at what age the use of spatial representation for spatial thinking skills should begin. This study investigated whether young Korean children possess the potential to understand map-like representation using aerial photographs; how scale affects children's performance; and whether children show interest in and enjoy working with spatial representations. Three remote sensing images of different scales were employed to examine children's ability to interpret spatial representation. The results indicate that young children have the ability to use spatial representation. Most participants were able to understand aerial photographs. The results also support the assertion that children's performance was influenced by scale. Especially for children whose ability is not fully developed, the scale effect was dramatic. Finally, children reported that they enjoyed activities using spatial representation.

Looking beyond the boundaries: Time to put landmarks back on the cognitive map?

Since the proposal of Tolman (1948) that mammals form maplike representations of familiar environments, cognitive map theory has been at the core of debates on the fundamental mechanisms of animal learning and memory. Traditional formulations of cognitive map theory emphasize relations between landmarks and between landmarks and goal locations as the basis of the map. More recently, several models of spatial coding have taken the boundaries of an environment as the basis of the cognitive map, with landmark relations being processed through alternative, operant learning mechanisms. In this review, the evidence for this proposed dichotomy is analyzed. It is suggested that 2 factors repeatedly confound efforts to compare spatial coding based on landmark arrays, formed by 2 or more landmarks, and that based on the boundaries of an environment. The factors are the perceived stability of the landmark arrays and their placement relative to the larger environment. Although the effects of landmark stability and of placement on spatial navigation have been studied extensively, the implications of this work for debates concerning the role of boundaries in cognitive map formation have not been fully realized. It is argued that when these 2 factors are equated between landmark arrays and bounded environments, current evidence supports a commonality of spatial coding mechanism rather than a dichotomy. The analysis places further doubt on the existence of a dedicated geometric module for reorientation and is consistent with models of navigation containing mapping and operant learning components, both taking as input local views (Sheynikhovich et al., 2009).

Head direction cell firing properties and behavioural performance in 3‐D space

Previous studies have identified a population of neurons in the rat brain that discharge as a function of the animal's directional heading in the horizontal plane, independent of their location and on-going behaviour. Most studies on head direction (HD) cells have explored how they respond in two-dimensional environments within the horizontal plane. Many animals, however, live and locomote in a three-dimensional world. This paper reviews how HD cells respond when the animal locomotes on a vertical surface or inverted on a ceiling. We found that HD cells fire in a normal, direction-dependent manner when the rat is in the vertical plane, but not when the animal is inverted. Recent behavioural studies reported that rats are capable of accurately performing a navigational task when inverted, but only when the task was simple and started from not more than one or two entry points. Probe trials found that they did not have a flexible, map-like representation of space when inverted. The loss of the directional signal when the animal is in an inverted orientation may account for the absence of the map-like representation. Taken together, these findings indicate that a normal otolith signal contributes an important role to HD cell discharge.

Distances between Real-World Locations Are Represented in the Human Hippocampus

Spatial navigation is believed to be guided in part by reference to an internal map of the environment. We used functional magnetic resonance imaging (fMRI) to test for a key aspect of a cognitive map: preservation of real-world distance relationships. University students were scanned while viewing photographs of familiar campus landmarks. fMRI response levels in the left hippocampus corresponded to real-world distances between landmarks shown on successive trials, indicating that this region considered closer landmarks to be more representationally similar and more distant landmarks to be more representationally distinct. In contrast, posterior visually responsive regions such as retrosplenial complex and the parahippocampal place area were sensitive to landmark repetition and encoded landmark identity in their multivoxel activity patterns but did not show a distance-related response. These data suggest the existence of a map-like representation in the human medial temporal lobe that encodes the coordinates of familiar locations in large-scale, real-world environments.

Crystals of the brain.

When we find our way in the environment, we need to integrate information about location, direction and distance into a coherent map-like representation. Our work over the last 10 years has suggested that the medial entorhinal cortex plays a central role in this process. A key component of the entorhinal network for spatial mapping is the grid cell, which we discovered, together with our colleagues, in 2005. Grid cells fire only when animals move through specific, regularly spaced positions. Their active firing positions form a hexagonal pattern that spans, for each cell, the entire local space available to the animal (Fig 1). The periodic pattern is reminiscent of the cross-points of graphic paper but the repeating units are equilateral triangles, not squares. Grid cells interact with other specialized cell types, such as head-direction cells and border cells. Head-direction cells signal orientation whereas border cells fire only near the edge of the local environment (Fig 2). Together, these entorhinal cells establish a coherent generic map of local space that is maintained across environments, independently of the animal's speed and direction and independently of the identity of the particular landmarks of the place. Figure 1 Entorhinal grid cell Figure 2 Border cells, grid cells and head direction cells are the elements of a metric representation of local space and are likely to be used when animals navigate through the environment »Grid cells have attracted attention because the crystal-like structure underlying their firing fields is not, like in sensory systems, imported from the outside world, but is created within the brain itself.« “One synapse” downstream, in the hippocampus, the map is associated with specific features and experiences, forming individualized maps that are stored in the neural networks of this brain region. Studies of grid cells may thus provide access to some of the basic computational operations of cortical circuits. In this Perspective, we shall review the work that led to the discovery of grid cells and the entorhinal spatial map, concluding with a brief look to the future.

Ligand efficiency indices for an effective mapping of chemico-biological space: the concept of an atlas-like representation

We propose a numerical framework that permits an effective atlas-like representation of chemico-biological space based on a series of Cartesian planes mapping the ligands with the corresponding targets connected by an affinity parameter (K(i) or related). The numerical framework is derived from the concept of ligand efficiency indices, which provide a natural coordinate system combining the potency toward the target (biological space) with the physicochemical properties of the ligand (chemical space). This framework facilitates navigation in the multidimensional drug discovery space using map-like representations based on pairs of combined variables related to the efficiency of the ligands per Dalton (molecular weight or number of non-hydrogen atoms) and per unit of polar surface area (or number of polar atoms).

You-Are-Here Maps: Creating Spatial Awareness through Map-like Representations

Spatial awareness and knowledge about one's location in an environment is a necessity for successful orientation, wayfinding, and navigation activities. Although familiar environments allow us the ...

Visual Targeting of Motor Actions in Climbing Drosophila

Drosophila melanogaster flies cross surmountable gaps in their walkway of widths exceeding their body length with an astounding maneuver but avoid attempts at insurmountable gaps by visual width estimation. Different mutant lines affect specific aspects of this maneuver, indicating a high complexity and modularity of the underlying motor control. Here we report on two mutants, ocelliless(1) and tay bridge(1), that, although making a correct decision to climb, fail dramatically in aiming at the right direction. Both mutants show structural defects in the protocerebral bridge, a central complex neuropil formed like a handlebar spanning the brain hemispheres. The bridge has been implicated in step-length control in walking flies and celestial E-vector orientation in locusts. In rescue experiments using tay bridge(1) flies, the integrity of the bridge was reestablished, concomitantly leading to a significant improvement of their orientation at the gap. Although producing directional scatter, their attempts were clearly aimed at the landing site. However, this partial rescue was lost in these flies at a reduced-visibility landing site. We therefore conclude that the protocerebral bridge is an essential part of a visual targeting network that transmits directional clues to the motor output via a known projection system.

Human hippocampal CA1 involvement during allocentric encoding of spatial information.

A central component of our ability to navigate an environment is the formation of a memory representation that is allocentric and thus independent of our starting point within that environment. Computational models and rodent electrophysiological recordings suggest a critical role for the CA1 subregion of the hippocampus in this type of coding; however, the hippocampal neural basis of spatial learning in humans remains unclear. We studied subjects learning virtual environments using high-resolution functional magnetic resonance imaging (1.6 mm x 1.6 mm in-plane) and computational unfolding to better visualize substructural changes in neural activity in the hippocampus. We show that the right posterior CA1 subregion is active and positively correlated with performance when subjects learn a spatial environment independent of starting point and direction. Altogether, our results demonstrate that the CA1 subregion is involved in our ability to learn a map-like representation of an environment.

Hippocampal‐dependent familiar area map supports corrective re‐orientation following navigational error during pigeon homing: a GPS‐tracking study

It is hypothesized that a central role of the vertebrate hippocampal formation (HF) in behavior is the learning and operation of a map-like representation of familiar landmarks and landscape features. One critical property of a map is that it should enable an individual to re-orient towards a goal location following a navigational error. To test this prediction on a spatial scale consistent with their naturally occurring behavior, control and HF-lesioned homing pigeons were trained from two locations and then subsequently released, while carrying portable GPS-tracking devices, following a phase-shift treatment. Analyses revealed that the HF-lesioned pigeons were less successful than control pigeons in re-orienting homewards following the phase-shift-induced error in their initial orientation. Furthermore, the observation that HF-lesioned pigeons were found to routinely ignore a land-sea landscape boundary when returning home from one of the release sites suggests that coarse landscape features may be an underappreciated source of navigational information for homing pigeons. The data demonstrate that, on a scale of tens of kilometers, homing pigeons are able to learn a hippocampal-dependent, map-like representation of familiar landmarks/landscape features that can support corrective re-orientation following a navigational error.

Selective influence of prior allocentric knowledge on the kinesthetic learning of a path

Spatial cognition studies have described two main cognitive strategies involved in the memorization of traveled paths in human navigation. One of these strategies uses the action-based memory (egocentric) of the traveled route or paths, which involves kinesthetic memory, optic flow, and episodic memory, whereas the other strategy privileges a survey memory of cartographic type (allocentric). Most studies have dealt with these two strategies separately, but none has tried to show the interaction between them in spite of the fact that we commonly use a map to imagine our journey and then proceed using egocentric navigation. An interesting question is therefore: how does prior allocentric knowledge of the environment affect the egocentric, purely kinesthetic navigation processes involved in human navigation? We designed an experiment in which blindfolded subjects had first to walk and memorize a path with kinesthetic cues only. They had previously been shown a map of the path, which was either correct or distorted (consistent shrinking or growing). The latter transformations were studied in order to observe what influence a distorted prior knowledge could have on spatial mechanisms. After having completed the first learning travel along the path, they had to perform several spatial tasks during the testing phase: (1) pointing towards the origin and (2) to specific points encountered along the path, (3) a free locomotor reproduction, and (4) a drawing of the memorized path. The results showed that prior cartographic knowledge influences the paths drawn and the spatial inference capacity, whereas neither locomotor reproduction nor spatial updating was disturbed. Our results strongly support the notion that (1) there are two independent neural bases underlying these mechanisms: a map-like representation allowing allocentric spatial inferences, and a kinesthetic memory of self-motion in space; and (2) a common use of, or a switching between, these two strategies is possible. Nevertheless, allocentric representations can emerge from the experience of kinesthetic cues alone.

Human factors in GIScience laboratory at the Pennsylvania State University

The human factors in GIScience Laboratory (Human Factors Lab) of The Pennsylvania State University's Department of Geography is located in University Park, PA (USA). University Park and bordering State College, PA are found in the heart of PA between the cities of New York City, NY, Philadelphia, PA, and Pittsburgh, PA. The laboratory is directed by Dr. Alexander Klippel and is part of the GeoVISTA Center. The Human Factors Lab contributes to Penn State Geography's strong tradition as a leader in research on map perception, spatial cognition, and behavior in spatial environments. This report focuses upon basic research topics in spatial cognition, including: (1) perceptual and cognitive factors in map symbolization and design, (2) the creation of cognitively ergonomic route directions for next generation location based services (LBS), (3) You-Are-Here maps and the creation of a sense of place through map-like representations, (4) the conceptualization and representation of dynamic phenomena (i.e., geographic movement pattern), and (5) the relationship between linguistic and non-linguistic conceptualization.

Maplike representation of celestial E-vector orientations in the brain of an insect

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.

The effects of a changing ambient magnetic field on single-unit activity in the homing pigeon hippocampus

The central representation of geomagnetic information in the avian brain continues to challenge researchers. Although the homing pigeon hippocampal formation primarily participates in the map-like representation of landmarks, some suggestive data indicate that it may also participate in spatial behavior guided by geomagnetic information. Forty-four isolated neurons were recorded from the hippocampal formation of homing pigeons trained to shuttle between two goal locations under changing (direction and intensity, and direction only) magnetic field conditions. Of the 37 slow-firing cells sampled (<14 spikes/s), none displayed a change in firing rate at the time of magnetic field transitions or during different ambient magnetic field conditions. By contrast, three of seven fast firing cells (>17 spikes/s) clearly displayed a phasic increase in firing during at least one of the magnetic field transitions used. The results are consistent with the hypothesis that a subset of hippocampal formation neurons receives information regarding changes in the earth's magnetic field that may be used to guide behavior.

The influence of intentional and incidental learning on acquiring spatial knowledge during navigation

In order to study the influence of intentional and incidental learning conditions on route learning, young adults walked a route through a university building. Half of the participants focused their attention on the route (intentional learning condition), while the other half did not (incidental learning condition). Five tests of spatial knowledge were employed: a route-length-estimation, landmark recognition, landmark ordering, map-drawing and navigation task. The intentional group performed better than the incidental group on the map-drawing and navigation task. No difference between the intentional and incidental group was found on the landmark-recognition and landmark-ordering task. Moreover, the intentional group overestimated the walking distance, while the incidental group underestimated it. These results suggest that route knowledge (landmark recognition and landmark ordering) requires less effortful processing than survey knowledge (developing a map-like representation and actual navigation).

Do familiar landmarks reset the global path integration system of desert ants?

It is often suggested that animals may link landmark memories to a global coordinate system provided by path integration, thereby obtaining a map-like representation of familiar terrain. In an attempt to discover if desert ants form such associations we have performed experiments that test whether desert ants recall a long-term memory of a global path integration vector on arriving at a familiar food site. Ants from three nests were trained along L-shaped routes to a feeder. Each route was entirely within open-topped channels that obscured all natural landmarks. Conspicuous artificial landmarks were attached to the channelling that formed the latter part of the route. The homeward vectors of ants accustomed to the route were tested with the foodward route, either as in training, or with the first leg of the L shortened or extended. These ants were taken from the feeder to a test area and released, whereupon they performed a home vector. If travelling the latter part of a familiar route and arriving at a familiar food site triggers the recall of an accustomed home vector, then the home vector should be the same under both test conditions. We find instead that the home vector tended to reflect the immediately preceding outward journey. In conjunction with earlier work, these experiments led us to conclude in the case of desert ants that landmark memories do not prime the recall of long-term global path integration memories. On the other hand, landmark memories are known to be linked to local path integration vectors that guide ants along a segment of a route. Landmarks thus seem to provide procedural information telling ants what action to perform next but not the positional information that gives an ant its location relative to its nest.

Memory use in insect visual navigation.

The navigational strategies that are used by foraging ants and bees to reach a goal are similar to those of birds and mammals. Species from all these groups use path integration and memories of visual landmarks to navigate through familiar terrain. Insects have far fewer neural resources than vertebrates, so data from insects might be useful in revealing the essential components of efficient navigation. Recent work on ants and bees has uncovered a major role for associative links between long-term memories. We emphasize the roles of these associations in the reliable recognition of visual landmarks and the reliable performance of learnt routes. It is unknown whether such associations also provide insects with a map-like representation of familiar terrain. We suggest, however, that landmarks act primarily as signposts that tell insects what particular action they need to perform, rather than telling them where they are.