scholarly journals Environmental anchoring of grid-like representations minimizes spatial uncertainty during navigation

2017 ◽  
Author(s):  
Tobias Navarro Schröder ◽  
Benjamin W. Towse ◽  
Matthias Nau ◽  
Neil Burgess ◽  
Caswell Barry ◽  
...  

SummaryMinimizing spatial uncertainty is essential for navigation, but the neural mechanisms remain elusive. Here we combine predictions of a simulated grid cell system with behavioural and fMRI measures in humans during virtual navigation. First, we showed that polarising cues produce anisotropy in motion parallax. Secondly, we simulated entorhinal grid cells in an environment with anisotropic information and found that self-location is decoded best when grid-patterns are aligned with the axis of greatest information. Thirdly, when exposing human participants to polarised virtual reality environments, we found that navigation performance is anisotropic, in line with the use of parallax. Eye movements showed that participants preferentially viewed polarising cues, which correlated with navigation performance. Finally, using fMRI we found that the orientation of grid-cell-like representations in entorhinal cortex anchored to the environmental axis of greatest parallax information, orthogonal to the polarisation axis. In sum, we demonstrate a crucial role of the entorhinal grid system in reducing uncertainty in representations of self-location and find evidence for adaptive spatial computations underlying entorhinal representations in service of optimal navigation.

2013 ◽  
Vol 25 (7) ◽  
pp. 1008-1019 ◽  
Author(s):  
Jeffrey S. Taube ◽  
Stephane Valerio ◽  
Ryan M. Yoder

Identifying the neural mechanisms underlying spatial orientation and navigation has long posed a challenge for researchers. Multiple approaches incorporating a variety of techniques and animal models have been used to address this issue. More recently, virtual navigation has become a popular tool for understanding navigational processes. Although combining this technique with functional imaging can provide important information on many aspects of spatial navigation, it is important to recognize some of the limitations these techniques have for gaining a complete understanding of the neural mechanisms of navigation. Foremost among these is that, when participants perform a virtual navigation task in a scanner, they are lying motionless in a supine position while viewing a video monitor. Here, we provide evidence that spatial orientation and navigation rely to a large extent on locomotion and its accompanying activation of motor, vestibular, and proprioceptive systems. Researchers should therefore consider the impact on the absence of these motion-based systems when interpreting virtual navigation/functional imaging experiments to achieve a more accurate understanding of the mechanisms underlying navigation.


2014 ◽  
Vol 369 (1635) ◽  
pp. 20130290 ◽  
Author(s):  
Benjamin W. Towse ◽  
Caswell Barry ◽  
Daniel Bush ◽  
Neil Burgess

We examined the accuracy with which the location of an agent moving within an environment could be decoded from the simulated firing of systems of grid cells. Grid cells were modelled with Poisson spiking dynamics and organized into multiple ‘modules’ of cells, with firing patterns of similar spatial scale within modules and a wide range of spatial scales across modules. The number of grid cells per module, the spatial scaling factor between modules and the size of the environment were varied. Errors in decoded location can take two forms: small errors of precision and larger errors resulting from ambiguity in decoding periodic firing patterns. With enough cells per module (e.g. eight modules of 100 cells each) grid systems are highly robust to ambiguity errors, even over ranges much larger than the largest grid scale (e.g. over a 500 m range when the maximum grid scale is 264 cm). Results did not depend strongly on the precise organization of scales across modules (geometric, co-prime or random). However, independent spatial noise across modules, which would occur if modules receive independent spatial inputs and might increase with spatial uncertainty, dramatically degrades the performance of the grid system. This effect of spatial uncertainty can be mitigated by uniform expansion of grid scales. Thus, in the realistic regimes simulated here, the optimal overall scale for a grid system represents a trade-off between minimizing spatial uncertainty (requiring large scales) and maximizing precision (requiring small scales). Within this view, the temporary expansion of grid scales observed in novel environments may be an optimal response to increased spatial uncertainty induced by the unfamiliarity of the available spatial cues.


2004 ◽  
Vol 63 (3) ◽  
pp. 143-149 ◽  
Author(s):  
Fred W. Mast ◽  
Charles M. Oman

The role of top-down processing on the horizontal-vertical line length illusion was examined by means of an ambiguous room with dual visual verticals. In one of the test conditions, the subjects were cued to one of the two verticals and were instructed to cognitively reassign the apparent vertical to the cued orientation. When they have mentally adjusted their perception, two lines in a plus sign configuration appeared and the subjects had to evaluate which line was longer. The results showed that the line length appeared longer when it was aligned with the direction of the vertical currently perceived by the subject. This study provides a demonstration that top-down processing influences lower level visual processing mechanisms. In another test condition, the subjects had all perceptual cues available and the influence was even stronger.


Author(s):  
Daniela Mazzaccaro ◽  
Rim Miri ◽  
Bilel Derbel ◽  
Paolo Righini ◽  
Giovanni Nano

Author(s):  
S Leinster-Evans ◽  
J Newell ◽  
S Luck

This paper looks to expand on the INEC 2016 paper ‘The future role of virtual reality within warship support solutions for the Queen Elizabeth Class aircraft carriers’ presented by Ross Basketter, Craig Birchmore and Abbi Fisher from BAE Systems in May 2016 and the EAAW VII paper ‘Testing the boundaries of virtual reality within ship support’ presented by John Newell from BAE Systems and Simon Luck from BMT DSL in June 2017. BAE Systems and BMT have developed a 3D walkthrough training system that supports the teams working closely with the QEC Aircraft Carriers in Portsmouth and this work was presented at EAAW VII. Since then this work has been extended to demonstrate the art of the possible on Type 26. This latter piece of work is designed to explore the role of 3D immersive environments in the development and fielding of support and training solutions, across the range of support disciplines. The combined team are looking at how this digital thread leads from design of platforms, both surface and subsurface, through build into in-service support and training. This rich data and ways in which it could be used in the whole lifecycle of the ship, from design and development (used for spatial acceptance, HazID, etc) all the way through to operational support and maintenance (in conjunction with big data coming off from the ship coupled with digital tech docs for maintenance procedures) using constantly developing technologies such as 3D, Virtual Reality, Augmented Reality and Mixed Reality, will be proposed.  The drive towards gamification in the training environment to keep younger recruits interested and shortening course lengths will be explored. The paper develops the options and looks to how this technology can be used and where the value proposition lies. 


2018 ◽  
Author(s):  
Lorraine Tudor Car ◽  
Bhone Myint Kyaw ◽  
Josip Car

BACKGROUND Digital technology called Virtual Reality (VR) is increasingly employed in health professions’ education. Yet, based on the current evidence, its use is narrowed around a few most applications and disciplines. There is a lack of an overview that would capture the diversity of different VR applications in health professions’ education and inform its use and research. OBJECTIVE This narrative review aims to explore different potential applications of VR in health professions’ education. METHODS The narrative synthesis approach to literature review was used to analyse the existing evidence. RESULTS We outline the role of VR features such as immersion, interactivity and feedback and explain the role of VR devices. Based on the type and scope of educational content VR can represent space, individuals, objects, structures or their combination. Application of VR in medical education encompasses environmental, organ and micro level. Environmental VR focuses on training in relation to health professionals’ environment and human interactions. Organ VR educational content targets primarily human body anatomy; and micro VR microscopic structures at the level of cells, molecules and atoms. We examine how different VR features and health professional education areas match these three VR types. CONCLUSIONS We conclude by highlighting the gaps in the literature and providing suggestions for future research.


2021 ◽  
pp. 0887302X2199428
Author(s):  
Hyejune Park ◽  
Seeun Kim

The purpose of this study is to examine the effects of the “virtual try-on” technology (AR) and the “3D virtual store” (VR) incorporated in an apparel retail website on purchase intentions. This study highlights the mediating role of cognitive elaboration in the process through which these technologies influence purchase intentions, and examines the way consumers’ shopping goals (searching vs. browsing) interact with the website technology and influence their responses. The two experiments demonstrated that, for browsers, the website with VR was more effective in increasing purchase intentions than were the website with AR or a regular website with no technology, while for searchers, both the website with AR and the website with VR were more effective than was a regular website. In addition, cognitive elaboration mediated the interaction between a technology and a shopping goal on purchase intentions for browsers, while such a mediating effect was not found in searchers.


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