Imagine Your Crossed Hands as Uncrossed: Visual Imagery Impacts the Crossed-Hands Deficit

Abstract Successful interaction with our environment requires accurate tactile localization. Although we seem to localize tactile stimuli effortlessly, the processes underlying this ability are complex. This is evidenced by the crossed-hands deficit, in which tactile localization performance suffers when the hands are crossed. The deficit results from the conflict between an internal reference frame, based in somatotopic coordinates, and an external reference frame, based in external spatial coordinates. Previous evidence in favour of the integration model employed manipulations to the external reference frame (e.g., blindfolding participants), which reduced the deficit by reducing conflict between the two reference frames. The present study extends this finding by asking blindfolded participants to visually imagine their crossed arms as uncrossed. This imagery manipulation further decreased the magnitude of the crossed-hands deficit by bringing information in the two reference frames into alignment. This imagery manipulation differentially affected males and females, which was consistent with the previously observed sex difference in this effect: females tend to show a larger crossed-hands deficit than males and females were more impacted by the imagery manipulation. Results are discussed in terms of the integration model of the crossed-hands deficit.

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Response Demands and Blindfolding in the Crossed-Hands Deficit: An Exploration of Reference Frame Conflict

Multisensory Research ◽

10.1163/22134808-00002423 ◽

2013 ◽

Vol 26 (5) ◽

pp. 465-482 ◽

Cited By ~ 12

Author(s):

Michelle L. Cadieux ◽

David I. Shore

Keyword(s):

Reference Frame ◽

Visual Information ◽

Reference Frames ◽

Internal Reference ◽

Eyes Closed ◽

External Reference ◽

Eyes Open ◽

Temporal Order Judgments ◽

Visual Conditions

Performance on tactile temporal order judgments (TOJs) is impaired when the hands are crossed over the midline. The cause of this effect appears to be tied to the use of an external reference frame, most likely based on visual information. We measured the effect of degrading the external reference frame on the crossed-hand deficit through restriction of visual information across three experiments. Experiments 1 and 2 examined three visual conditions (eyes open–lights on, eyes open–lights off, and eyes closed–lights off) while manipulating response demands; no effect of visual condition was seen. In Experiment 3, response demands were altered to be maximally connected to the internal reference frame and only two visual conditions were tested: eyes open–lights on, eyes closed–lights off. Blindfolded participants had a reduced crossed-hands deficit. Results are discussed in terms of the time needed to recode stimuli from an internal to an external reference frame and the role of conflict between these two reference frames in causing this effect.

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Exploring Reference Frame Integration Using Response Demands in a Tactile Temporal-Order Judgement Task

Multisensory Research ◽

10.1163/22134808-bja10057 ◽

2021 ◽

pp. 1-32

Author(s):

Kaian Unwalla ◽

Daniel Goldreich ◽

David I. Shore

Keyword(s):

Reference Frame ◽

Reference Frames ◽

Temporal Order ◽

Relative Weight ◽

Internal Reference ◽

Spatial Reference ◽

Spatial Reference Frames ◽

External Reference ◽

Temporal Order Judgement ◽

Bias Condition

Abstract Exploring the world through touch requires the integration of internal (e.g., anatomical) and external (e.g., spatial) reference frames — you only know what you touch when you know where your hands are in space. The deficit observed in tactile temporal-order judgements when the hands are crossed over the midline provides one tool to explore this integration. We used foot pedals and required participants to focus on either the hand that was stimulated first (an anatomical bias condition) or the location of the hand that was stimulated first (a spatiotopic bias condition). Spatiotopic-based responses produce a larger crossed-hands deficit, presumably by focusing observers on the external reference frame. In contrast, anatomical-based responses focus the observer on the internal reference frame and produce a smaller deficit. This manipulation thus provides evidence that observers can change the relative weight given to each reference frame. We quantify this effect using a probabilistic model that produces a population estimate of the relative weight given to each reference frame. We show that a spatiotopic bias can result in either a larger external weight (Experiment 1) or a smaller internal weight (Experiment 2) and provide an explanation of when each one would occur.

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Parallel updating and weighting of multiple spatial maps for visual stability during whole body motion

Journal of Neurophysiology ◽

10.1152/jn.00576.2015 ◽

2015 ◽

Vol 114 (6) ◽

pp. 3211-3219 ◽

Cited By ~ 10

Author(s):

J. J. Tramper ◽

W. P. Medendorp

Keyword(s):

Reference Frame ◽

Reference Frames ◽

Spatial Information ◽

Target Location ◽

Visual Space ◽

Body Motion ◽

Whole Body ◽

Spatial Representations ◽

Integration Model ◽

The Brain

It is known that the brain uses multiple reference frames to code spatial information, including eye-centered and body-centered frames. When we move our body in space, these internal representations are no longer in register with external space, unless they are actively updated. Whether the brain updates multiple spatial representations in parallel, or whether it restricts its updating mechanisms to a single reference frame from which other representations are constructed, remains an open question. We developed an optimal integration model to simulate the updating of visual space across body motion in multiple or single reference frames. To test this model, we designed an experiment in which participants had to remember the location of a briefly presented target while being translated sideways. The behavioral responses were in agreement with a model that uses a combination of eye- and body-centered representations, weighted according to the reliability in which the target location is stored and updated in each reference frame. Our findings suggest that the brain simultaneously updates multiple spatial representations across body motion. Because both representations are kept in sync, they can be optimally combined to provide a more precise estimate of visual locations in space than based on single-frame updating mechanisms.

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Object-Centered Neglect in Patients with Unilateral Neglect: Effects of Left-Right Coordinates of Objects

Journal of Cognitive Neuroscience ◽

10.1162/jocn.1994.6.1.1 ◽

1994 ◽

Vol 6 (1) ◽

pp. 1-16 ◽

Cited By ~ 91

Author(s):

Marlene Behrmann ◽

Morris Moscovitch

Keyword(s):

Reference Frame ◽

Reference Frames ◽

Frame Of Reference ◽

The Other ◽

Unilateral Neglect ◽

Independent Measure ◽

Object Based ◽

Spatial Coordinates ◽

Left And Right

When patients with right-sided hemispheric lesions neglect information on the left side, with respect to what set of spatial coordinates is left defined? Two potential reference frames were examined in this study, one where left and right are defined with respect to the midline of the viewer and/or environment (viewer/env-centered) and the other where left and right are defined with respect to the midline of the object (object-centered). By rotating the stimulus 90° clockwise or counterclockwise, and instructing patients with neglect to report the colors appearing around the border of a stimulus, an independent measure was obtained for the number of colors reported from the left and right of the viewer/env- and from the object-based reference frame. Whereas significant object-centered neglect was observed only for upper case asymmetrical letters but not for symmetrical letters nor for drawings of familiar animals or objects, significant viewer/env-based neglect was observed with all the stimulus types. We present an account of the coexistence of neglect in more than one frame of reference and the presence of object-centered neglect under a restricted set of conditions.

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Adaptation aftereffects reveal that tactile distance is a basic somatosensory feature

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.1614979114 ◽

2017 ◽

Vol 114 (17) ◽

pp. 4555-4560 ◽

Cited By ~ 15

Author(s):

Elena Calzolari ◽

Elena Azañón ◽

Matthew Danvers ◽

Giuseppe Vallar ◽

Matthew R. Longo

Keyword(s):

Reference Frame ◽

Distance Perception ◽

Simultaneous Presentation ◽

Passive Touch ◽

Low Level ◽

Early Stages ◽

Skin Region ◽

Tactile Stimuli ◽

External Reference

The stage at which processing of tactile distance occurs is still debated. We addressed this issue by implementing an adaptation-aftereffect paradigm with passive touch. We demonstrated the presence of a strong aftereffect, induced by the simultaneous presentation of pairs of tactile stimuli. After adaptation to two different distances, one on each hand, participants systematically perceived a subsequent stimulus delivered to the hand adapted to the smaller distance as being larger. We further investigated the nature of the aftereffects, demonstrating that they are orientation- and skin-region–specific, occur even when just one hand is adapted, do not transfer either contralaterally or across the palm and dorsum, and are defined in a skin-centered, rather than an external, reference frame. These characteristics of tactile distance aftereffects are similar to those of low-level visual aftereffects, supporting the idea that distance perception arises at early stages of tactile processing.

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Reliability of the Crossed-Hands Deficit in Tactile Temporal Order Judgements

Multisensory Research ◽

10.1163/22134808-bja10039 ◽

2020 ◽

pp. 1-35

Author(s):

Kaian Unwalla ◽

Hannah Kearney ◽

David I. Shore

Keyword(s):

Individual Differences ◽

Reference Frame ◽

Reference Frames ◽

Temporal Order ◽

High Reliability ◽

Stimulus Location ◽

The Other ◽

Good Reliability ◽

External Reference ◽

Temporal Order Judgement

Abstract Crossing the hands over the midline impairs performance on a tactile temporal order judgement (TOJ) task, resulting in the crossed-hands deficit. This deficit results from a conflict between two reference frames — one internal (somatotopic) and the other external (spatial) — for coding stimulus location. The substantial individual differences observed in the crossed-hands deficit highlight the differential reliance on these reference frames. For example, women have been reported to place a greater emphasis on the external reference frame than men, resulting in a larger crossed-hands deficit for women. It has also been speculated that individuals with an eating disorder place a greater weight on the external reference frame. Further exploration of individual differences in reference frame weighing using a tactile TOJ task requires that the reliability of the task be established. In Experiment 1, we investigated the reliability of the tactile TOJ task across two sessions separated by one week and found high reliability in the magnitude of the crossed-hands deficit. In Experiment 2, we report the split-half reliability across multiple experiments (both published and unpublished). Overall, tactile TOJ reliability was high. Experiments with small to moderate crossed-hands deficits showed good reliability; those with larger deficits showed even higher reliability. Researchers should try to maximize the size of the effect when interested in individual differences in the use of the internal and external reference frames.

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Disentangling the External Reference Frames Relevant to Tactile Localization

PLoS ONE ◽

10.1371/journal.pone.0158829 ◽

2016 ◽

Vol 11 (7) ◽

pp. e0158829 ◽

Cited By ~ 10

Author(s):

Tobias Heed ◽

Jenny Backhaus ◽

Brigitte Röder ◽

Stephanie Badde

Keyword(s):

Reference Frames ◽

Tactile Localization ◽

External Reference

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Multiple Spatial Coordinates Influence the Prediction of Tactile Events Facilitated by Approaching Visual Stimuli

Multisensory Research ◽

10.1163/22134808-bja10045 ◽

2021 ◽

pp. 1-21

Author(s):

Tsukasa Kimura

Keyword(s):

Visual Information ◽

High Probability ◽

Tactile Stimulus ◽

Reference Frames ◽

Index Finger ◽

Visual Stimuli ◽

The Body ◽

Spatial Reference Frames ◽

Tactile Stimuli ◽

Spatial Coordinates

Abstract Interaction with other sensory information is important for prediction of tactile events. Recent studies have reported that the approach of visual information toward the body facilitates prediction of subsequent tactile events. However, the processing of tactile events is influenced by multiple spatial coordinates, and it remains unclear how this approach effect influences tactile events in different spatial coordinates, i.e., spatial reference frames. We investigated the relationship between the prediction of a tactile stimulus via this approach effect and spatial coordinates by comparing ERPs. Participants were asked to place their arms on a desk and required to respond tactile stimuli which were presented to the left (or right) index finger with a high probability (80%) or to the opposite index finger with a low probability (20%). Before the presentation of each tactile stimulus, visual stimuli approached sequentially toward the hand to which the high-probability tactile stimulus was presented. In the uncrossed condition, each hand was placed on the corresponding side. In the crossed condition, each hand was crossed and placed on the opposite side, i.e., left (right) hand placed on the right (left) side. Thus, the spatial location of the tactile stimulus and hand was consistent in the uncrossed condition and inconsistent in the crossed condition. The results showed that N1 amplitudes elicited by high-probability tactile stimuli only decreased in the uncrossed condition. These results suggest that the prediction of a tactile stimulus facilitated by approaching visual information is influenced by multiple spatial coordinates.

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UNIFORMLY ACCELERATING REFERENCE FRAMES AND THE EQUIVALENCE PRINCIPLE

International Journal of Modern Physics D ◽

10.1142/s021827180801270x ◽

2008 ◽

Vol 17 (07) ◽

pp. 1071-1085 ◽

Cited By ~ 2

Author(s):

CHAO-GUANG HUANG

Keyword(s):

Reference Frame ◽

High Precision ◽

Equivalence Principle ◽

Reference Frames ◽

Arrival Time ◽

Space Time ◽

Second Law ◽

Leading Order ◽

Relativistic Limit ◽

Spatial Coordinates

In addition to the well-known Møller frame (or Rindler frame), we may construct another frame to describe the uniformly accelerating system. In the new frame, all "static" (i.e. spatial coordinates keeping constant) observers have the same proper acceleration but each has his own horizon. In contrast, the proper acceleration of a static observer in the Møller frame (or Rindler frame) depends on his position, but the horizon is (static-) observer-independent. We argue that the new uniformly accelerating reference frame is more suitable than the Møller frame to describe the system in an accelerating spacecraft. It is possible to distinguish the Møller frame and the new frame by high-precision experiments (such as arrival-time- and/or redshift-measurements) in an accelerating spacecraft. When the non-relativistic limit is taken, the second law of mechanics and Schrödinger equation in the new uniformly accelerating frame are all different from those in the Møller frame. The effects on the equivalence principle are discussed. We argue that even when the space–time curvature is ignored, it is still possible in some sense to distinguish gravity from acceleration at the next leading order.

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Haptic awareness changes when lying down

Scientific Reports ◽

10.1038/s41598-021-92192-1 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Kaian Unwalla ◽

Michelle L. Cadieux ◽

David I. Shore

Keyword(s):

Reference Frame ◽

Visual Information ◽

Reference Frames ◽

Temporal Order ◽

Bayesian Hierarchical ◽

Accurate Localization ◽

External Reference ◽

Vestibular Information ◽

Temporal Order Judgement ◽

Lying Down

AbstractAccurate localization of touch requires the integration of two reference frames—an internal (e.g., anatomical) and an external (e.g., spatial). Using a tactile temporal order judgement task with the hands crossed over the midline, we investigated the integration of these two reference frames. We manipulated the reliability of the visual and vestibular information, both of which contribute to the external reference frame. Visual information was manipulated between experiments (Experiment 1 was done with full vision and Experiment 2 was done while wearing a blindfold). Vestibular information was manipulated in both experiments by having the two groups of participants complete the task in both an upright posture and one where they were lying down on their side. Using a Bayesian hierarchical model, we estimated the perceptual weight applied to these reference frames. Lying participants on their side reduced the weight applied to the external reference frame and produced a smaller deficit; blindfolding resulted in similar reductions. These findings reinforce the importance of the visual system when weighting tactile reference frames, and highlight the importance of the vestibular system in this integration.

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