Egocentric Cues Research Articles

Organization of the reach and grasp in head-fixed vs freely-moving mice provides support for multiple motor channel theory of neocortical organization.

Multiple motor channel (MMC) theory of neocortical organization proposes that complex movements, such as reaching for a food item to eat, are produced by the coordinated action of separate neural channels. For example, the human reach-to-grasp act is mediated by two visuo-parieto-motor cortex channels, one for the reach and one for the grasp. The present analysis asked whether there is a similar organization of reach-and-grasp movements in the mouse. The reach-to-eat movements of the same mice were examined from high-shutter speed, frame-by-frame video analysis in three tasks in which the mice obtained equivalent success scores: when freely-moving reaching for food pellets, when head-fixed reaching for food pellets, and when head-fixed reaching for pieces of pasta. To reach, the mice used egocentric cues to vary upper arm movements in a task-appropriate manner to place an open hand on the food or to locate the food using a "touch-release-grasp" strategy. Although mice could not hand-shape offline when reaching, they could hand-shape using online touch-related cues from the mouth to manipulate the food at the mouth. That the reach can be performed offline in relation to egocentric cues whereas hand shaping for the grasp requires online cues supports the idea that for the mouse, as for primates, the reach and grasp are separate acts. The results are further discussed in relation to the use of the head-fixed behavioral procedure to identify the independent neural substrates of the reach and the grasp using mesoscale stimulation/imaging methods.

Unilateral lesions of the dorsocentral striatum (DCS) disrupt spatial and temporal characteristics of food protection behavior.

Spatial and temporal information processing provide a foundation for higher cognitive functions. The survival of animals depends on integrating spatial and temporal information to organize behavior. In general, previous research has focused on only one source of information processing; however, there is evidence to support a convergence in the processing of egocentric-spatial and temporal information within a cortico-striatal system of structures. The current study evaluated the contributions of the dorsocentral striatum (DCS) to egocentric-spatial and temporal (within the seconds-to-minutes range) processing of information using a food protection task. Long-Evans rats received unilateral NMDA lesions of the DCS followed by testing in a food protection task. Performance in this task is mediated by the motivation of the animal to consume a food item, their perception of the time required to consume a food item, their sensory ability to process egocentric cues, and their motor ability to evade an incoming conspecific. Unilateral DCS lesions were shown to impact both spatial and temporal characteristics of food protection. These results suggest that the DCS may be a critical structure for the integration of egocentric-spatial and temporal information within the interval timing range.

Flipping a Switch "Down" When Not Aligned with the Gravitational Vertical.

To flip a switch "down," our motor system can normally rely on concordant visual, gravitational, and egocentric cues about the vertical. However, divers must sometimes perform this task while visual cues are limited and gravitational cues are misaligned with egocentric cues. Astronauts must also flip switches "down" in absence of gravitational cues. Our study evaluates this ability using a laboratory simulation. The subjects were 24 healthy volunteers who were blindfolded, tilted into different angles of roll, and asked to silence an alarm by flipping a switch "down." The switch was constructed such that it could be flipped in any direction in the subjects' frontal plane. Two subjects deflected the switch in accordance with the direction of gravity, irrespective of their body orientation. Twenty subjects deflected it in accordance with their body orientation, irrespective of the direction of gravity. The remaining two persons could not be classified unequivocally. Notably, some egocentric responders deflected the rod consistently toward their feet, but others deflected it consistently toward other parts of their body. Since our findings disagree with perceptual studies where gravitational rather than egocentric cues predominated in the absence of vision, we posit that perception and action may access distinct internal representations of the vertical. On the practical side, our findings indicate that designers of spaceflight and underwater equipment should not rely on divers' intuitive knowledge on how to flip a switch "down." Bock O, Bury N. Flipping a switch "down" when not aligned with the gravitational vertical. Aerosp Med Hum Perform. 2016; 87(10):838-843.

Error Analysis for Localizing Egocentric Multimodal Cues in the Presence of Helicopter Noise

Loss of situation awareness (SA) remains a problem in aviation and can result in spatial disorientation (SD). Attempts to remedy the problem through non-visual displays have used 3-dimensional (3D) audio and vibrotaction. It is possible that the operational environment may not facilitate the use of 3D audio aircraft noise, fore-aft sound confusions, and pilot hearing loss. The present study looked at the effect of the first variable (ambient noise) on participants’ performance for localizing egocentric 3D audio, tactile, and redundant audiotactile cues in the presence of continuous helicopter noise. Accuracy rates were significantly better and errors were less disperse for tactile and audiotactile cues, suggesting that displaying information to pilots through these modalities could yield substantially better performance versus 3D audio alone.

Delving into Egocentric Actions.

We address the challenging problem of recognizing the camera wearer's actions from videos captured by an egocentric camera. Egocentric videos encode a rich set of signals regarding the camera wearer, including head movement, hand pose and gaze information. We propose to utilize these mid-level egocentric cues for egocentric action recognition. We present a novel set of egocentric features and show how they can be combined with motion and object features. The result is a compact representation with superior performance. In addition, we provide the first systematic evaluation of motion, object and egocentric cues in egocentric action recognition. Our benchmark leads to several surprising findings. These findings uncover the best practices for egocentric actions, with a significant performance boost over all previous state-of-the-art methods on three publicly available datasets.

Allocentric coding: Spatial range and combination rules

When a visual target is presented with neighboring landmarks, its location can be determined both relative to the self (egocentric coding) and relative to these landmarks (allocentric coding). In the present study, we investigated (1) how allocentric coding depends on the distance between the targets and their surrounding landmarks (i.e. the spatial range) and (2) how allocentric and egocentric coding interact with each other across targets-landmarks distances (i.e. the combination rules). Subjects performed a memory-based pointing task toward previously gazed targets briefly superimposed (200ms) on background images of cluttered city landscapes. A variable portion of the images was occluded in order to control the distance between the targets and the closest potential landmarks within those images. The pointing responses were performed after large saccades and the reappearance of the images at their initial location. However, in some trials, the images’ elements were slightly shifted (±3°) in order to introduce a subliminal conflict between the allocentric and egocentric reference frames. The influence of allocentric coding in the pointing responses was found to decrease with increasing target-landmarks distances, although it remained significant even at the largest distances (⩾10°). Interestingly, both the decreasing influence of allocentric coding and the concomitant increase in pointing responses variability were well captured by a Bayesian model in which the weighted combination of allocentric and egocentric cues is governed by a coupling prior.

Episodic Memory as Re-Experiential Memory: Kantian, Developmental, and Neuroscientific Currents

Recent work on the early development of episodic memory in my laboratory has been fuelled by the following assumption: if episodic memory is re-experiential memory then Kant’s analysis of the spatiotemporal nature of experience should constrain and positively influence theories of episodic memory development. The idea is that re-experiential memory will “inherit” these spatiotemporal features. On the basis of this assumption, Russell and Hanna (Mind and Language 27(1):29–54, 2012) proposed that (a) the spatial element of re-experience is egocentric and (b) that the temporal element of re-experiencing involves order/simultaneity. The first of these assumptions is immediately problematic for two reasons. In the first place, if we assume that early episodic recall mediated by processing in the hippocampus, then (a) is clearly in tension with the fact that spatial coding in the hippocampus is allocentric/environment-centred. Second, two of our own recent experiments (described here) show that when only egocentric cues are available in a What/When/Where episodic memory task it is not possible to distinguish young children’s performance from semantic memory. I argue that this tension should be resolved by recognising that the egocentric coding of the original experience as being of an objective scene relies upon allocentric representations and these are preserved in re-experiential memory, allowing a recollection of the objective nature of the scene on which one takes a subjective view.

Interaction of egocentric and world-centered reference frames in the rat posterior parietal cortex.

Navigation requires coordination of egocentric and allocentric spatial reference frames and may involve vectorial computations relative to landmarks. Creation of a representation of target heading relative to landmarks could be accomplished from neurons that encode the conjunction of egocentric landmark bearings with allocentric head direction. Landmark vector representations could then be created by combining these cells with distance encoding cells. Landmark vector cells have been identified in rodent hippocampus. Given remembered vectors at goal locations, it would be possible to use such cells to compute trajectories to hidden goals. To look for the first stage in this process, we assessed parietal cortical neural activity as a function of egocentric cue light location and allocentric head direction in rats running a random sequence to light locations around a circular platform. We identified cells that exhibit the predicted egocentric-by-allocentric conjunctive characteristics and anticipate orienting toward the goal.

Immediate and delayed recall of a small-scale spatial array

The study examined people's spatial memory of a small-scale array of objects. Earlier work has primarily relied on short-retention intervals, and to date it is not known whether performance is affected by longer intervals between learning and recall. In the present investigation, university students studied seven target objects. Recall was tested immediately after learning and after an interval of seven days. Performance was found to be similar in the immediate and delayed conditions, and the results suggested that recall was facilitated by egocentric and intrinsic cues. The findings are discussed with reference to recent investigations that have shown task parameters can influence spatial recall.

An evaluation of immersive viewing on spatial knowledge acquisition in spherical panoramic environments

We report the results of an experiment conducted to examine the effects of immersive viewing on a common spatial knowledge acquisition task of spatial updating task in a spherical panoramic environment (SPE). A spherical panoramic environment, such as Google Street View, is an environment that is comprised of spherical images captured at regular intervals in a real world setting augmented with virtual navigational aids such as paths, dynamic maps, and textual annotations. Participants navigated the National Mall area of Washington, DC, in Google Street View in one of two viewing conditions; desktop monitor or a head-mounted display with a head orientation tracker. In an exploration phase, participants were first asked to navigate and observe landmarks on a pre-specified path. Then, in a testing phase, participants were asked to travel the same path and to rotate their view in order to look in the direction of the perceived landmarks at certain waypoints. The angular difference between participants' gaze directions and the landmark directions was recorded. We found no significant difference between the immersive and desktop viewing conditions on participants' accuracy of direction to landmarks as well as no difference in their sense of presence scores. However, based on responses to a post-experiment questionnaire, participants in both conditions tended to use a cognitive or procedural technique to inform direction to landmarks. Taken together, these findings suggest that in both conditions where participants experience travel based on teleportation between waypoints, the visual cues available in the SPE, such as street signs, buildings and trees, seem to have a stronger influence in determining the directions to landmarks than the egocentric cues such as first-person perspective and natural head-coupled motion experienced in the immersive viewing condition.

Flexible Spatial Orientation and Navigational Strategies in Chambered Nautilus

AbstractNautilus is a remnant of an externally shelled cephalopod lineage that flourished between 450 and 60 million years ago. It is a deep‐water scavenger that lacks the complex brain and behavioural repertoire of its soft‐bodied relatives, the coleoid cephalopods. Nautilus makes repeated, nightly migrations from deep to shallow water along coral reef slopes to forage, thus an ability to navigate to known locations may be selectively advantageous. Alternatively, drifting passively with the current may be sufficient to locate food and mates distributed randomly over a large area. The derived neural structures that support learning and memory in coleoids are absent from the nautilus brain, indicating that substantial differences between learning abilities in nautilus and coleoids are likely. However, our previous work has demonstrated both associative and spatial learning in nautilus. In laboratory experiments, we tested whether Nautilus pompilius could learn to navigate towards a goal location using either visual cues or motor responses. Results indicate that animals relied both on proximate and distant visual cues to orient but did not use egocentric cues, a somewhat surprising finding given that nautilus spends most of its time in near darkness. Animals learned visual information rapidly and in some cases were able to switch to other tactics when salient visual cues were removed or manipulated.

Reframing the action and perception dissociation in DF: haptics matters, but how?

Goodale and Milner's (1992) "vision-for-action" and "vision-for-perception" account of the division of labor between the dorsal and ventral "streams" has come to dominate contemporary views of the functional roles of these two pathways. Nevertheless, some lines of evidence for the model remain controversial. Recently, Thomas Schenk reexamined visual form agnosic patient DF's spared anticipatory grip scaling to object size, one of the principal empirical pillars of the model. Based on this new evidence, Schenk rejects the original interpretation of DF's spared ability that was based on segregated processing of object size and argues that DF's spared grip scaling relies on haptic feedback to calibrate visual egocentric cues that relate the posture of the hand to the visible edges of the goal-object. However, a careful consideration of the tasks that Schenk employed reveals some problems with his claim. We suspect that the core issues of this controversy will require a closer examination of the role that cognition plays in the operation of the dorsal and ventral streams in healthy controls and in patient DF.

Influence of habitat complexity on route learning among different populations of climbing perch (Anabas testudineus Bloch, 1792)

Animals use different behavioral strategies to maximize their fitness in the natural environment. Learning and memory are critical in this context, allowing organisms to flexibly and rapidly respond to environmental changes. We studied how the physical characteristics of the native habitat influence the spatial learning capacity of Anabas testudineus belonging to four different populations collected from two streams and two ponds, in a linear maze. Stream fish were able to learn the route faster than pond fish irrespective of the presence or absence of landmarks in the maze. However, climbing perch collected from ponds learned the route faster in the maze provided with landmarks than in Plain maze. The results indicate that fish inhabiting a lotic ecosystem use egocentric cues in route learning rather than visual cues like landmarks. A local landmark may be a more reliable cue in route learning in a relatively stable habitat like a pond. In flowing aquatic systems, water flow may continually disrupt the visual landscape and thus landmarks as visual cues become unreliable. Spatial learning is thus a fine-tuned response to the complexity of the habitat and early rearing conditions may influence the spatial learning ability in fish.

Haptic experiences influence visually acquired memories: Reference frames during multimodal spatial learning

In two experiments, we investigated whether reference frames acquired through touch could influence memories for locations learned through vision. Participants learned two objects through touch, and haptic egocentric (Experiment 1) and environmental (Experiment 2) cues encouraged selection of a specific reference frame. Participants later learned eight new objects through vision. Haptic cues were manipulated, whereas visual learning was held constant in order to observe any potential influence of the haptically experienced reference frame on memories for visually learned locations. When the haptically experienced reference frame was defined primarily by egocentric cues, cue manipulation had no effect on memories for objects learned through vision. Instead, visually learned locations were remembered using a reference frame selected from the visual study perspective. When the haptically experienced reference frame was defined by both egocentric and environmental cues, visually learned objects were remembered in the context of the haptically experienced reference frame. These findings support the common reference frame hypothesis, which proposes that locations learned through different sensory modalities are represented within a common reference frame.

Children's Visual Processing of Egocentric Cues in Action Planning for Reach

In this study the authors examined children's ability to code visual information into an egocentric frame of reference for planning reach movements. Children and adults estimated reach distance via motor imagery in immediate and response-delay conditions. Actual maximum reach was compared to estimates in multiple locations in peripersonal and extrapersonal space. Analysis of variance results for total accuracy indicated no group difference in the no-delay condition; however, delay differences emerged. Concerning the direction of error, results indicated that as delay increased, children as a whole overestimated more than adults did. These findings suggest that younger children may have more difficulty planning memory-guided tasks.

64. Virtual navigation by patients with epilepsy under two different spatial conditions: Use of allocentric vs. egocentric cues

64. Virtual navigation by patients with epilepsy under two different spatial conditions: Use of allocentric vs. egocentric cues

Evidence for differential weighting of egocentric and allocentric cues in delayed and real-time actions

Evidence for differential weighting of egocentric and allocentric cues in delayed and real-time actions

Interaction between Egocentric and Exocentric Frames of Reference Assessed by Perceptual Constancy Parameters

Distance from a stimulus, stimulus size and orientation with respect to the observer are relevant metric properties of visual space. However, whether and how these metrics are related to each other is not well known. Some studies have shown that estimates of egocentric distances are usually more accurate than judgments of exocentric distances, suggesting that there is dissociation between ‘localization’ judgments and ‘size’ judgments. Other investigations have revealed that the orientation of the stimulus influences the accuracy of size estimations. To better understand the relationships between these metric properties of visual space, we conducted an experiment to compare size perception as a function of orientation from viewer egocentric and exocentric frames of reference (FoR). Observers were instructed to draw two circles on a screen by clicking with a mouse when the screen was positioned on either the frontoparallel plane or the ground plane. From an egocentric FoR, egocentric distance and direction were processed asymmetrically, as knowledge of the particular combination of both size and orientation was always needed to compute visual direction. However, in terms of the accuracy of size estimates (S 0 /S) from an exocentric FoR, size and orientation were independent for all conditions. Therefore, the orientation did not need to be computed in order to compute the size. Regarding exocentric direction or orientation (α 0 /α), size and orientation were only dependent when the two points were presented successively. In conclusion, these findings suggest that orientation and distance always interact and that distance, visual direction or orientation require an egocentric cue.

Reference Frame Congruency in Search-and-Rescue Tasks

Our aim was to investigate how the congruency between visual displays and auditory cues affects performance on various spatial tasks. Previous studies have demonstrated that spatial auditory cues, when combined with visual displays, can enhance performance and decrease workload. However, this facilitation was achieved only when auditory cues shared a common reference frame (RF) with the visual display. In complex and dynamic environments, such as airborne search and rescue (SAR), it is often difficult to ensure such congruency. In a simulated SAR operation, participants performed three spatial tasks: target search, target localization, and target recall. The interface consisted of the camera view of the terrain from the aircraft-mounted sensor, a map of the area flown over, a joystick that controlled the sensor, and a mouse. Auditory cues were used to indicate target location. While flying in the scenario, participants searched for targets, identified their locations in one of two coordinate systems, and memorized their location relative to the terrain layout. Congruent cues produced the fastest and most accurate performance. Performance advantages were observed even with incongruent cues relative to neutral cues, and egocentric cues were more effective than exocentric cues. Although the congruent cues are most effective, in cases in which the same cue is used across spatial tasks, egocentric cues are a better choice than exocentric cues. Egocentric auditory cues should be used in display design for tasks that involve RF transformations, such as SAR, air traffic control, and unmanned aerial vehicle operations.

Long‐term deficits on a foraging task after bilateral vestibular deafferentation in rats

Animal studies have shown that bilateral vestibular deafferentation (BVD) causes deficits in spatial memory that may be related to electrophysiological and neurochemical changes in the hippocampus. Recently, human studies have also indicated that human patients can exhibit spatial memory impairment and hippocampal atrophy even 8-10 yr following BVD. Our previous studies have shown that rats with unilateral vestibular deafferentation (UVD) showed an impairment at 3 months after the surgery on a food foraging task that relies on hippocampal integration of egocentric cues, such as vestibular information; however, by 6 months postop, they showed a recovery of function. By contrast, the long-term effects of BVD on spatial navigation have never been well studied. In this study, we tested BVD or sham rats on a food foraging task at 5 months postop. Under light conditions, BVD rats were able to use visual cues to guide themselves home, but did so with a significantly longer homing time. However, in darkness, BVD rats were severely impaired in the foraging task, as indicated by a significantly longer homing distance and homing time, with more errors and larger heading angles when compared with sham rats. These results suggest that, unlike UVD, BVD causes long-term deficits in spatial navigation that are unlikely to recover, even with repeated T-maze training.