Egocentric Cues Research Articles

Both egocentric and allocentric cues support spatial priming in visual search

The perception–action model proposes that vision for perception and vision for action are subserved by two separate cortical systems, the ventral and dorsal streams, respectively [Milner, A. D., & Goodale, M. A. (1995). The visual brain in action (1st ed.). Oxford: Oxford University Press; Milner, A. D., & Goodale, M. A. (2006). The visual brain in action (2nd ed.). Oxford: Oxford University Press Inc.]. The dorsal stream codes spatial information egocentrically, that is, relative to the observer. Egocentric representations are argued to be highly transient; therefore, it might be expected that egocentric information cannot be used for spatial memory tasks, even when the visual information only needs to be retained for a few seconds. Here, by applying a spatial priming paradigm to a visual search task, we investigated whether short-term spatial memory can use egocentric information. Spatial priming manifests itself in speeded detection times for a target when that target appears in the same location it previously appeared in. Target locations can be defined in either egocentric or allocentric (i.e. relative to other items in the display) frames of reference; however, it is unclear which of these are used in spatial priming, or if both are. Our results show that both allocentric and egocentric cues were used in spatial priming, and that egocentric cues were in fact more effective than allocentric cues for short-term priming. We conclude that egocentric information can persist for several seconds; a conclusion which is at odds with the assumption of the perception–action model that egocentric representations are highly transient.

Courtship herding in the fiddler crab Uca elegans: tracking control system

Animals with limited neural processing power require simple control systems for guiding behaviour. The fiddler crab Uca elegans uses both allocentric cues from the visual environment and egocentric cues from path integration to guide movements during courtship. As part of their courtship system, male U. elegans intercept moving females in a behaviour termed outward run. These outward runs require males to track the position of females visually, navigate towards them, and manoeuvre themselves into a position ready for subsequent courtship activity. Using digital video cameras positioned above the mudflat, we recorded and analysed 22 naturally occurring outward runs. By measuring the visual location of females from the viewpoint of males, we found that, during the approach, males maintained the target female position within a specific region of the posteriolateral visual field. Also, outward-running males moved on average 5.5 cm/s faster than target females. This led us to propose a relatively simple control system for guiding the outward run which accounts for the observed tracking behaviour. The control system is based on two simple rules. (1) Move towards the target female while maintaining her retinal image within a narrow strip of the posteriolateral visual field. (2) As you approach, move the fixation point for the female's image slowly towards a more posterior position. These guidance rules do not require the males to adjust their speed in relation to the female. As long as they are faster than the female, the interception will be successful.

Impaired, spared, and enhanced ACh efflux across the hippocampus and striatum in diencephalic amnesia is dependent on task demands

Diencephalic amnesia manifests itself through a host of neurological and memory impairments. A commonly employed animal model of diencephalic amnesia, pyrithiamine-induced thiamine deficiency (PTD), results in brain lesions and impairments similar in nature and distribution to those observed in humans with Wernicke–Korsakoff syndrome (WKS). In the current investigation, 2 separate experiments were conducted in which acetylcholine (ACh) efflux was assessed in the hippocampus and striatum of PTD-treated and pair-fed (PF) control male Sprague–Dawley rats. The goal was to determine under what behavioral conditions and in which brain structures ACh efflux was spared, impaired, or adaptively enhanced. In Experiment 1, rats were assessed on a spontaneous alternation task; in Experiment 2, rats were tested on a T-maze discrimination task that could be learned via a hippocampal- or striatal-based strategy. In Experiment 1, PTD-treated rats were impaired on the spontaneous alternation task and ACh efflux in the hippocampus during testing was significantly reduced, but spared in the striatum. In Experiment 2, PTD- and PF-treated rats did not differ in the number of trials to criterion, but PTD-treated rats demonstrated greater reliance upon egocentric cues to solve the task. Furthermore, ACh efflux in the striatum was greater during maze learning in the PTD-treated animals when compared to the PF animals. These results suggest that there is behavioral and systems level plasticity that can facilitate the use of alternative strategies to solve a task following diencephalic damage and WKS.

Emergence of an egocentric cue guiding and allocentric inferring strategy that mirrors hippocampal brain-derived neurotrophic factor (BDNF) expression in the Morris water maze

From insects to humans, successful navigation relies on retained representations of spatial relations. These representations are thought to depend on the hippocampal formation, particularly those that are independent of the navigator (allocentric representations). The Morris water maze is a simple and popular task often used to assess spatial navigation. But how animals navigate toward and retain information regarding the location of the goal in this task remains unclear. We provide a comprehensive account of how the water maze is accomplished behaviourally. Our findings suggest that animals solve the task using distal cues via an initial view-matching strategy that is supported by egocentric guidance. Through increased training, however, an emergence of an egocentric-guiding strategy combined with the animal’s greater ability to infer the hidden platform’s location (via allocentric extrapolation) emerges. We also demonstrate that behavioural changes, towards a more allocentric strategy, are reflected in increases in hippocampal brain-derived neurotrophic factor.

Rats’ responsiveness to tactile changes encountered in the dark, and the role of mystacial vibrissae

This study aimed to assess male and female rats’ ability to utilize egocentric cues for detecting a change in tactile stimulation encountered in the dark (and possible sex differences). It also investigated the role of mystacial vibrissae in tactile discrimination in this particular setting. Hooded rats of both sexes were accordingly exposed, in the dark, to Y-maze arms with either two rough (sandpaper) or two smooth floors (Perspex), or one rough and one smooth floor. One of the floors was then changed to the opposite type of surface and the rats’ ability to locate and explore this changed (or novel) arm in the dark was measured. Both sexes were able to complete this task successfully thereby suggesting that they had used egocentric body cues, rather than visual or olfactory cues for locating the position of the novel arm. Because rats with all their mystacial vibrissae removed were not seriously disadvantaged in locating and exploring the tactually novel arm, it appeared that their ability to discriminate between the tactile properties of the maze arms was not crucially reliant on their whiskers and allied trigeminal system, and may have also involved tactile receptors in their paws. It was concluded that rats of both sexes were able to utilize egocentric cues in detecting a tactile change, and did not rely exclusively on mystacial vibrissae for discriminating between the tactile properties of the maze-arm floors.

Cues used by male and female hooded rats for locating a brightness change

Entries of and time spent in a novel Y-maze arm that had changed from white (during acquisition trials) to black (during retention trials) were investigated in male and female Long-Evans hooded rats after the apparatus had been horizontally rotated through 180 degrees or left undisturbed. Maze rotation reduced responsiveness to this arm in males but not in females. When each arm was associated with a different set of visual cues, males significantly chose the novel arm only in the presence of intra- and extra-maze cues either alone or in combination. Females significantly selected the novel arm only in the absence of either type of cue, and in the presence of intra-maze cues alone. However, when the duration of acquisition trials was increased from 6 to 12min, females also selected the novel arm in the presence of both intra- and extra-maze cues. It was concluded that, while female rats appeared able to use egocentric (or response-related) cues for locating the novel arm, males were more dependent on allocentric (or place-related) cues following shorter acquisition trials. Because of the importance of such cues, it seemed that the task of recognizing which maze arm had changed in brightness defined the test as one of spatial memory.

Congruency between Visual and Auditory Displays on Spatial Tasks Using Different Reference Frames

This study investigated the effectiveness of spatial auditory cues for tasks using different reference frames, and examined how congruency between auditory and visual displays affected performance. Performance with three types of auditory cues (egocentric, exocentric and non-spatial) was compared on three spatial tasks: target search, target localization and target recall. There was a clear effect of reference frame congruency between auditory and visual displays on target search and target localization tasks. Interestingly, even incongruent auditory cues improved performance relative to non-spatial control conditions. In addition, egocentric auditory cues facilitated performance more than exocentric cues on incongruent trials. The findings have important implications for display design in work environments that involve diverse spatial tasks and displays that use different reference frames.

Müller-Lyer figures influence the online reorganization of visually guided grasping movements

In advance of grasping a visual object embedded within fins-in and fins-out Müller-Lyer (ML) configurations, participants formulated a premovement grip aperture (GA) based on the size of a neutral preview object. Preview objects were smaller, veridical, or larger than the size of the to-be-grasped target object. As a result, premovement GA associated with the small and large preview objects required significant online reorganization to appropriately grasp the target object. We reasoned that such a manipulation would provide an opportunity to examine the extent to which the visuomotor system engages egocentric and/or allocentric visual cues for the online, feedback-based control of action. It was found that the online reorganization of GA was reliably influenced by the ML figures (i.e., from 20 to 80% of movement time), regardless of the size of the preview object, albeit the small and large preview objects elicited more robust illusory effects than the veridical preview object. These results counter the view that online grasping control is mediated by absolute visual information computed with respect to the observer (e.g., Glover in Behav Brain Sci 27:3-78, 2004; Milner and Goodale in The visual brain in action 1995). Instead, the impact of the ML figures suggests a level of interaction between egocentric and allocentric visual cues in online action control.

Differential roles of distracters in reflexive and memory-based localization

We investigated the effects of spatial and temporal factors on manual localization of a visual target by measuring accuracy, precision, and bias. Spatial factors included manipulation of display as with or without distracters, with invariant or variant distracters, and with near or far distracters, respectively, in Experiments 1, 2, and 3. The target and distracters were of 1degrees dots differing only by luminance parameter; they were presented concurrently for 150 or 1000 ms while observers had to memorize the target location maintaining a fixed gaze. The observers' task was to reproduce the location of the target with a mouse cursor available 150 ms following stimuli offset. Results from all experiments showed that localization performance for a briefly exposed target was as accurate and precise as that for a long exposed target. Moreover, manipulation of spatial factors had no systematic effects on accuracy and precision except that near distracters yielded higher precision. Interestingly, localization performance was unbiased in 150 ms condition when there were distracters in the display, while being biased towards the fovea in 1000 ms condition regardless of their presence or absence. These results suggest a temporal dynamics in dominance-suppression between egocentric and exocentric cues in the construction of memory for location.

Frames of reference in spatial memories acquired from language.

Four experiments examined reference systems in spatial memories acquired from language. Participants read narratives that located 4 objects in canonical (front, back, left, right) or noncanonical (left front, right front, left back, right back) positions around them. Participants' focus of attention was first set on each of the 4 objects, and then they were asked to report the name of the object at the location indicated by a direction word or an iconic arrow. The results indicated that spatial memories were represented in terms of intrinsic (object-to-object) reference systems, which were selected using egocentric cues (e.g., alignment with body axes). Results also indicated that linguistic direction cues were comprehended in terms of egocentric reference systems, whereas iconic arrows were not.

Selective rotation of egocentric spatial representation following right putaminal hemorrhage

Although the role of frontoparietal cortex in spatial egocentric processing is well established, recent animal-lesion and human functional imaging studies have suggested that the neostriatum may also be a critical modulator in the processing of body-centred spatial orientation. We describe here a patient with right putamen-centred hemorrhage who exhibited a consistent counterclockwise rotation of approximately 90° when drawing and writing from memory. A more detailed assessment with a series of representational clock tests demonstrated that the rotation was present only in tasks requiring the use of egocentric cues. In the absence of external cues the patient would adopt and maintain a stable but incorrectly-oriented egocentric representation of the imagined or recollected object. By contrast, performance could be rectified by presentation of correctly-oriented stimuli. These findings suggest that the putamen is part of a circuit underlying egocentric, as opposed to allocentric, representation of space in humans.

Learning associations between places and visual cues without learning to navigate: neither fornix nor entorhinal cortex is required.

Rats with fornix transection, or with cytotoxic retrohippocampal lesions that removed entorhinal cortex plus ventral subiculum, performed a task that permits incidental learning about either allocentric (Allo) or egocentric (Ego) spatial cues without the need to navigate by them. Rats learned eight visual discriminations among computer-displayed scenes in a Y-maze, using the constant-negative paradigm. Every discrimination problem included two familiar scenes (constants) and many less familiar scenes (variables). On each trial, the rats chose between a constant and a variable scene, with the choice of the variable rewarded. In six problems, the two constant scenes had correlated spatial properties, either Allo (each constant appeared always in the same maze arm) or Ego (each constant always appeared in a fixed direction from the start arm) or both (Allo + Ego). In two No-Cue (NC) problems, the two constants appeared in randomly determined arms and directions. Intact rats learn problems with an added Allo or Ego cue faster than NC problems; this facilitation provides indirect evidence that they learn the associations between scenes and spatial cues, even though that is not required for problem solution. Fornix and retrohippocampal-lesioned groups learned NC problems at a similar rate to sham-operated controls and showed as much facilitation of learning by added spatial cues as did the controls; therefore, both lesion groups must have encoded the spatial cues and have incidentally learned their associations with particular constant scenes. Similar facilitation was seen in subgroups that had short or long prior experience with the apparatus and task. Therefore, neither major hippocampal input-output system is crucial for learning about allocentric or egocentric cues in this paradigm, which does not require rats to control their choices or navigation directly by spatial cues.

Solving spatial tasks with unaligned layouts: The difficulty of dealing with conflicting information

Previous research has shown that preschool children have difficulty using relational information in spatial tasks. The present study investigates whether this difficulty is due, in part, to children’s inability to deal with situations of conflict where both objective and egocentric cues are available and point to different responses. Two studies were conducted to compare performance in the presence versus absence of conflicting cues. In Study 1, 40 four-year-olds had to locate an object in a single layout presented from different perspectives. In Study 2, 39 four-year-olds had to transfer locational information between two unaligned layouts. The presence of conflict significantly affected children’s performance in both studies. The results are discussed in the context of similar findings in other cognitive domains.

Training Method Dramatically Affects the Acquisition of a Place Response in Rats with Neurotoxic Lesions of the Hippocampus

A considerable number of studies have demonstrated that hippocampal damage impairs the acquisition of a place response in rats. In Experiment 1, using a four-arm plus-shaped maze, we replicated this finding. Experiment 2 showed, however, that hippocampally damaged rats can learn a place response just as well as control rats when, during the training, a salient intramaze landmark indicates the position of the goal (the west arm). After reaching criterion, the hippocampal and control groups performed the task with the same degree of mastery during a transfer test in which the intramaze signal used during the acquisition was removed. In Experiment 3, the intramaze cue was substituted by an egocentric cue. The results revealed that both control and lesioned subjects learned the spatial problem well. However, a transfer test showed that control rats learned the task using a place response strategy but hippocampally lesioned animals used a rigid, hyperspecific strategy. Taken together, these results suggest that special training procedures which encourage variability in response versus perseveration make it possible to overcome the acquisition deficit normally observed in hippocampal rats.

The effect of the Ebbinghaus illusion on grasping behaviour of children.

Within the context of the Ebbinghaus illusion, adults regularly misjudge the physical size of a centre disc, yet scale their hand aperture according to its actual size. Separate visual pathways for perception and action are assumed to account for this finding. The dorsal visual stream is said to elaborate on egocentric (visuomotor), while the ventral stream is involved in allocentric transformations (object recognition). This study examines the ontogenetic development of this dissociation between perception and action in 35 children between the ages of 5 and 12 years. We report four major results. First, when children judged object size without grasping the disc, their judgements were deceived by the illusion to the same extent as adults. However, when asked to estimate size and then to grasp the disc, young children's (5-7 years) perceptual judgements became unreliable, while adults were still reliably deceived by the illusion in 80% of their trials. Second, the younger the children, the more their aperture was affected by the illusional surround. Discs of the same size were grasped with a smaller aperture when surrounded by a small annulus, although they were perceived as being larger. Third, young children used the largest safety margin during grasping. Fourth, the reliance on visual feedback decreased with increasing age, which was documented by shorter movement times and earlier maximum hand opening during grasping in the older children (feedforward control). Our results indicate that grasping behaviour in children is subject to an interaction between ventral and dorsal processes. Both pathways seem not to be functionally segregated in early and middle childhood. The data are inconclusive about whether young children predominantly use a specific visual stream for either a perceptual or motor task. However, our data demonstrate that children were relying on both visual processing streams during perceptual as well as visuomotor tasks. We found that children used egocentric cues to make perceptual judgements, while their grasping gestures were not exclusively shaped by viewer-centred but also by object-centred information.

Effects of ageing on allocentric and egocentric spatial strategies in the Wistar rat

This study was designed to assess the effect of ageing on spatial (allocentric and egocentric) strategies in rats. Two different tasks were designed for this purpose: one involving Morris' circular pool (distal extramaze cues) and another using the T water maze (egocentric cues). In the first task, the aged rats showed some difficulty in acquiring allocentric spatial learning skills. After increasing the number of trials in this task, there was no significant improvement in the performance of the aged group of rats compared to the adult group. However, in the second spatial task (using egocentric cues), both age groups gave a similar performance. Therefore, the effect of ageing on spatial learning depends on the strategy required to acquire this learning.

A double dissociation between the rat hippocampus and medial caudoputamen in processing two forms of knowledge.

Rats with hippocampus, medial caudoputamen (CPU), lateral CPU, or control lesions were trained on declarative and procedural knowledge variants of a novel rodent sequential learning task. Medial CPU lesions impaired rats' ability to learn the procedure of running through a sequence of open maze arms but did not disrupt their capacity to explicitly generate (i.e.. "declare") maze arm sequences. Hippocampus lesions produced the opposite set of results. Rats with lateral CPU lesions were not impaired on either version of the task. Transfer tests indicated that control rats predominantly used egocentric cues to solve the procedural task and allocentric spatial cues to solve the declarative task. These findings suggest a double dissociation between the medial CPU and hippocampus in processing egocentric-procedural and allocentric-declarative sequential information, respectively.

Deficit in the Water-Maze After Lesions in the Anteromedial Extrastriate Cortex in Rats

The Morris water-maze task was used to evaluate the role of the anteromedial extrastriate visual cortex in the processing of visuospatial information in rats. Six gray male rats received bilateral ibotenic acid injections targeted stereotactically to the rostral part of the anteromedial extrastriate visual cortex. These operated subjects and six other unoperated control rats were tested in the maze. Histological analysis confirmed the localization, symmetry, and depth of lesions in the rostral part of anteromedial area (AMa) in the operated subjects. In these animals, a significantly greater latency to reach the submerged platform was found ( U = 0, p = 0.004). The Morris water-maze may be considered as a reference memory task. It presents a stronger demand on the use of allocentric spatial visual cues than on the use of egocentric cues for navigation. Therefore, the present data lend support to the participation of area AMa in the integration of allocentric visuospatial cues or as a link in the memory system involved in the acquisition of this task.

6-month-old infants dishabituate to a change in an object's actual postion and not to a change in an object's egocentric position

Efficient navigation is a critical component of fitness for most animals. While most species use a combination of allocentric (external) and egocentric (internal) cues to navigate through their environment, subterranean environments present a unique challenge in that visually mediated allocentric cues are unavailable. The relationship between egocentric spatial cognition and species differences in ecology is surprisingly understudied. We used a maze-learning task to test for differences in egocentric navigation between two closely related species of mice, the eastern house mouse, Mus musculus musculus, and the mound-building mouse, Mus spicilegus. The two species are sympatric in Eastern Europe and overlap in summer habitat use but differ dramatically in winter space use: whereas house mice occupy anthropogenic structures, mound-building mice survive the winter underground in intricate burrow systems. Given species differences in burrowing ecology, we predicted that M. spicilegus would learn the maze significantly faster than M. m. musculus when tested in complete darkness, a condition that eliminated allocentric spatial information and served as a proxy for the subterranean environment. We found strong support for this prediction. In contrast, the two species performed equally well when different mice were tested in the same maze with lights on. This context-specific species difference in spatial cognition suggests that enhanced egocentric navigation in M. spicilegus is an adaptation to the burrow systems on which the overwinter survival of young mound-building mice depends. The results of this study highlight the importance of ecological adaptations to the evolution of cognitive traits.

The effect of visual context on manual localization of remembered targets.

This paper examines the contribution of egocentric cues and visual context to manual localization of remembered targets. Subjects pointed in the dark to the remembered position of a target previously viewed without or within a structured visual scene. Without a remembered visual context, subjects pointed to within 2 degrees of the target. The presence of a visual context with cues of straight ahead enhanced pointing performance to the remembered location of central but not off-center targets. Thus, visual context provides strong visual cues of target position and the relationship of body position to target location. Without a visual context, egocentric cues provide sufficient input for accurate pointing to remembered targets.