The Role of a Conventional Transformation Scheme for Vertical Reference Frames

2012 ◽  
pp. 215-220
Author(s):  
C. Kotsakis
Keyword(s):  
Reference Frames

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

2013 ◽  
Vol 26 (5) ◽  
pp. 465-482 ◽  
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.

Development of human spatial cognition in a three-dimensional world

2013 ◽  
Vol 36 (5) ◽  
pp. 556-556
Author(s):  
Kate A. Longstaffe ◽  
Bruce M. Hood ◽  
Iain D. Gilchrist
Keyword(s):  
Spatial Cognition ◽  
Reference Frames ◽  
Three Dimensional ◽  
Typically Developing ◽  
Typically Developing Children ◽  
Spatial Reference ◽  
Spatial Reference Frames

AbstractJeffery et al. accurately identify the importance of developing an understanding of spatial reference frames in a three-dimensional world. We examine human spatial cognition via a unique paradigm that investigates the role of saliency and adjusting reference frames. This includes work with adults, typically developing children, and children who develop non-typically (e.g., those with autism).

scholarly journals Lateral entorhinal cortex lesions impair both egocentric and allocentric object–place associations

2020 ◽  
Vol 4 ◽  
pp. 239821282093946
Author(s):  
Maneesh V. Kuruvilla ◽  
David I. G. Wilson ◽  
James A. Ainge
Keyword(s):  
Entorhinal Cortex ◽  
Reference Frames ◽  
Spatial Information ◽  
Unit Recording ◽  
Egocentric Reference Frame ◽  
Spatial Frames Of Reference ◽  
Significant Difference ◽  
Cue Processing ◽  
The Impact

During navigation, landmark processing is critical either for generating an allocentric-based cognitive map or in facilitating egocentric-based strategies. Increasing evidence from manipulation and single-unit recording studies has highlighted the role of the entorhinal cortex in processing landmarks. In particular, the lateral (LEC) and medial (MEC) sub-regions of the entorhinal cortex have been shown to attend to proximal and distal landmarks, respectively. Recent studies have identified a further dissociation in cue processing between the LEC and MEC based on spatial frames of reference. Neurons in the LEC preferentially encode egocentric cues while those in the MEC encode allocentric cues. In this study, we assessed the impact of disrupting the LEC on landmark-based spatial memory in both egocentric and allocentric reference frames. Animals that received excitotoxic lesions of the LEC were significantly impaired, relative to controls, on both egocentric and allocentric versions of an object–place association task. Notably, LEC lesioned animals performed at chance on the egocentric version but above chance on the allocentric version. There was no significant difference in performance between the two groups on an object recognition and spatial T-maze task. Taken together, these results indicate that the LEC plays a role in feature integration more broadly and in specifically processing spatial information within an egocentric reference frame.

The role of visual experience in spatial reference frame preference

2012 ◽  
Vol 25 (0) ◽  
pp. 18
Author(s):  
Achille Pasqualotto
Keyword(s):  
Reference Frame ◽  
Spatial Representation ◽  
Visual Experience ◽  
Reference Frames ◽  
Single Point ◽  
Memory Test ◽  
Object Locations ◽  
Congenitally Blind ◽  
Spatial Reference Frame

How do people remember the location of objects? Location is always relative, and thus depends on a reference frame. There are two types of reference frames: egocentric (or observer-based) and allocentric (or environmental-based). Here we investigated the reference frame people used to remember object locations in a large room. We also examined whether the choice of a given reference frame is dictated by visual experience. Thus we tested congenitally blind, late blind, and sighted blindfolded participants. Objects were organized in a structured configuration and then explored one-by-one with participants walking back and forth from a single point. After the exploration of the locations, a spatial memory test was conducted. The memory test required participants to imagine being inside the array of objects, being oriented along a given heading, and then pointing towards the required object. Crucially the headings were either aligned to the allocentric structure of the configuration, that is rows and columns, or aligned to the egocentric route walked during the exploration of the objects. The spatial representation used by the participants can be revealed by better performance when the imagined heading in the test matches the spatial representation used. We found that participants with visual experience, that is late blind and blindfolded sighted, were better with headings aligned to the allocentric structure of the configuration. On the contrary, congenitally blind were more accurate with headings aligned to the egocentric walked routes. This suggests that visual experience during early development determines a preference for an allocentric frame of reference.

Assessing the role of corrections included in the GRACE/GRACE-FO data in determination of hydrological and cryospheric signal in polar motion excitation

2021 ◽  
Author(s):  
Justyna Śliwińska ◽  
Małgorzata Wińska ◽  
Jolanta Nastula
Keyword(s):  
Angular Momentum ◽  
Polar Motion ◽  
Reference Frames ◽  
Temporal Variations ◽  
Terrestrial Reference Frames ◽  
Geophysical Processes ◽  
Terrestrial Water ◽  
Hydrological Angular Momentum ◽  
The Impact

<p>Assessing the impact of continental hydrosphere and cryosphere on polar motion (PM) variations is one of the crucial tasks in contemporary geodesy. The pole coordinates, as one of the Earth Orientation Parameters, are needed to define the relationship between the celestial and terrestrial reference frames. Therefore, the variations in PM should be monitored and interpreted in order to assess the role of geophysical processes in this phenomenon.</p><p>The role of hydrological and cryospheric signals in PM is usually examined by computing hydrological excitation (hydrological angular momentum, HAM) and cryospheric excitation (cryospheric angular momentum, CAM) of  PM, commonly treated together as HAM/CAM.</p><p>The Gravity Recovery and Climate Experiment (GRACE) and GRACE Follow-On (GRACE-FO) missions deliver temporal variations of the gravity field resulting from changes in global mass redistribution. The so-called GRACE/GRACE-FO Level-3 (L3) data delivers changes in terrestrial water storage (TWS) that can be used for computation of HAM/CAM.</p><p>For best possible representation of TWS, a number of corrections are introduced in the L3 data by computing centres. Such corrections are, among others, glacial isostatic adjustment (GIA) correction, geocenter correction and C<sub>20</sub> coefficient correction.</p><p>The main goal of this study is to examine the impact of corrections included in GRACE/GRACE-FO data on HAM/CAM determined. More specifically, we test their influence on HAM/CAM trends, seasonal changes and non-seasonal variations. We also examine the change in compliance between HAM/CAM and hydrological plus cryospheric signal in geodetically observed excitation when the corrections are used. To achieve our goals, we use GRACE and GRACE-FO L3 datasets provided by Jet Propulsion Laboratory (JPL), Center for Space Research (CSR), and Goddard Space Flight Center (GSFC).</p>

Contribution of proprioception for calibrating and updating the motor space

1995 ◽  
Vol 73 (2) ◽  
pp. 246-254 ◽  
Author(s):  
Chantal Bard ◽  
Michelle Fleury ◽  
Normand Teasdale ◽  
Jacques Paillard ◽  
Vincent Nougier
Keyword(s):  
Reference Frames ◽  
Sensory Information ◽  
Force Production ◽  
Movement Control ◽  
Spatial Reference Frames ◽  
Proprioceptive Afferents ◽  
The Brain ◽  
Prismatic Adaptation ◽  
Central Level

The absence of muscular proprioception, whether at a segmental or at a central level, impairs performance in several ways. The contribution of proprioception to movement control and learning is not easily dissociated from that of other sources of sensory information (e.g., vision). Therefore, the rare clinical cases of extensive neuropathy, depriving the brain massively and permanently of its presumed main sources of dynamogenic information from skin and muscles, are of very special interest. Two such patients and controls were tested in experiments investigating (i) force production, (ii) amplitude coding, (iii) spatial reference frames in pointing, and (iv) prismatic adaptation. Overall, our results highlight the key role of proprioceptive afferents for calibrating the spatial motor frame of reference, and the powerful substitutive properties of the central nervous system.Key words: proprioception, deafferentation, space calibration, motor control.

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