Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 17 of 17 for “"Path integration"”.
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The Mechanisms of Path Integration in Humans
Path integration refers to the ability to integrate self-motion information to estimate one's current position and orientation relative to the origin. We used a homing task in virtual hallway-mazes to investigate the mechanisms of path integration in humans. First, we examined spatial updating in …
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The impact of two spatial strategies on entorhinal and hippocampal involvement in visual path integration
… the involvement of the hippocampal formation in path integration, the current study investigated the extent to which the hippocampus proper, the entorhinal cortex, and neocortical regions were activated based on the implementation of continuous and configural updating strategies when performing a …
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Virtual reality navigation assessment and 7 tesla MR imaging of the entorhinal-hippocampal circuit in asymptomatic at-risk Alzheimer's disease
… cortex (EC), and that EC neurons contribute to path integration-based navigation, this thesis aimed to test the hypothesis that path integration would be impaired in people at risk of AD, prior to symptom onset. In Experiment 1, path integration was assessed using an immersive virtual reality …
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Maze Learning and Recall in Weakly Electric Fish, Mormyrus rume proboscirostris Boulenger 1898 (Teleostei, Mormyridae): Sensory Bases
… taxes, landmark and compass orientation, and path integration to cognitive maps. The debate concerning the use of mapping strategies, or less complex mechanisms such path integration, landmark orientation, or dead reckoning is far from settled. Nocturnal weakly electric fish (family …
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Navigating Virtual Environments At Scale
… does not generate any optical flow, limits path integration, e.g., estimating the total distance travelled, which can cause spatial disorientation. Dash is a modified teleportation technique that quickly but continuously displaces the viewpoint as to retain some optical flow and …
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The function and structure of the entorhinal cortex in mild cognitive impairment
… of EC function using novel iVR paradigms of path integration and object-location memory. Total EC, pm-EC and al-EC volumes were segmented from high resolution MRI. A proportion of MCI patients underwent CSF testing for AD biomarkers to separate into biomarker-positive and negative groups …
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A Neuronal Circuit Motif for Leaky Vector Integration
… perform this fundamental computation––known as path integration––even though neural correlates and computer models abound. In arthropods, spatial-cognition related processes such as path integration are thought to be implemented in the central complex. Experimenters have shown that contiguously …
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Escape processes far from thermal equilibrium : path integrals and force spectroscopy
… the second part of this thesis, the technique of path integration is employed to develop an approximation to the instantaneous escape rate that applies to arbitrarily modulated potentials and temperatures. As such systems are far from thermal equilibrium, the physics is not restricted by the …
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4D Study of Thoracic Cancer Radiation Treatment
… 4-D computed tomography imaging; demonstrate the path integration of a four-dimensional dose distribution onto the 3-D anatomy; develop an automated target delineation technique; and to develop and implement a method to quantify tumor response and normal tissue damage by comparison of pre- and …
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Path-integral analysis of passive, graded-index waveguides applicable to integrated optics
The Feynman path integral is used to describe paraxial, scalar wave propagation in weakly inhomogeneous media of the type encountered in passive integrated-optical communication devices. Most of the devices considered in this work are simple models for graded-index waveguide structures, such as …
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Ship Rolling Motion Subjected to Colored Noise Excitation
… the stochastic differential equations by using path integral method based on Gauss-Legendre interpolation scheme. The time-dependent probability of ship rolling restricted within the safe domain is provided and capsizing is investigated in the probability?s view. The random differential equation …
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Quantum Algorithms and Complexity for Numerical Problems
… numerical problems, such as high-dimensional integration and path integration, our adiabatic algorithms can be directly generalized to these kinds of problems. In addition, we study the quantum PAC learning model, offering an improved lower bound on the query complexity. The lower bound is …
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Human Visual Navigation: Effects of Visual Context, Navigation Mode, and Gender
… This thesis extends research on human visual path integration using optic flow cues. In three experiments, a large-scale path-completion task was contextualised within highly-textured authentic virtual environments. Real-world navigational experience was further simulated, through the …
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Finding back home: from vector models to virtual forests
… combine information derived from their path integration system with different numbers of landmark cues in a series of virtual forest environments. I show that human navigators are best able to return to a goal location placed in between a small number of "landmark" objects and argue that …
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AB-INITIO DYNAMICS IN STRONGLY INTERACTING MANY-BODY SYSTEMS
… attractive because they are related to the path integration formalism (a SWF can be seen as a single step of path integration [5]), so they are solidly grounded in the physics of a system. In Chapter 2 we mainly address the main novelty of our work, that is the extension of t-VMC to SWFs, …
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Mechanisms underlying spatial navigation
… by input-dependent fixed points, which allowed path integration error to be reset by anchoring. An input-dependent continuous attractor was also present, allowing the current location to be remembered while the agent stopped. These dynamical elements allowed the current location on the track to …
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Mechanisms of hippocampal relational memory binding
… disruption, whether it attacks molecular pathways (e.g., neurotransmitters, protein synthesis), individual neurons or synapses, entire brain structures, or even networks of structures, will become less effective with time as the information it seeks to disrupt becomes more globally …