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 12 of 12 for “"head direction"”.
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Cortico-thalamic interactions for head direction coding
… multiple brain areas carrying information about head and body movements as well as external sensory cues for reference. To adapt to changing environments and correct for error, head direction (HD) representations must be flexible. However, the circuit mechanisms and dynamics underlying how HD is …
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Mechanisms underlying spatial navigation
… fields of a grid cell appear to be influenced by head direction, and that each firing field has its own head direction preference. This surprising ‘local’ influence of head direction could be used by downstream networks to disambiguate points of view at various locations to aid in navigation. …
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Dynamics and learning in recurrent neural networks
… in detail: The first one is a network model for direction selectivity; the second one is a generalized network of Winner-Take-All; the third one is a model for integration in head-direction systems. One distinctive feature of neural systems is the ability of learning. The other part of my thesis …
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Building an Allocentric Traveling-Direction Signal Via Vector Computation
… in Drosophila and mammals that track an animal's heading angle referenced to external cues (e.g., head-direction cells), but this new signal illuminates how the sense of space is properly updated when traveling and heading angles differ (e.g., when walking sideways). We then characterize a …
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(Negative) concord and head directionality in Western Armenian
… involved. Negative morphemes, complementizer heads, and additive markers are optional in Western Armenian. These concord structures bring about some issues regarding head directionality. Western Armenian is a generally head-final language. Certain domains exhibit both head-initial and …
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Organised variations in space and time in the hippocampal representation of location
… cells often represent locations just behind/ahead of the animal, which may reflect the system recalling and planning routes through the environment. How this “time shift” varies between different cells, and throughout a trial, is unclear. This project investigates the principles that organise …
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Optimal anticipatory control as a theory of motor preparation
… is selectively controlled along state-space directions that have future motor consequences, and not in other inconsequential ones. We show that OFC enables fast movement preparation and explains the observed orthogonality between preparatory and movement-related monkey motor cortex activity. …
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Error correction in the hippocampal-medial-entorhinal cognitive map
… place cells, grid cells, border cells, and head direction cells. These cell types are thought to create, maintain, and update the cognitive map of the brain. However, they are also known to accumulate error with distance travelled and recent studies have shown that environmental clues have a …
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Theta oscillations, timing and cholinergic modulation in the rodent hippocampal circuit
… identified precession, including in conjunctive head-direction-by-grid cells and on passes that clipped the edge of the firing field. Secondly, I studied problems of measuring single neuron theta rhythmicity and developed an improved approach. Using the novel approach, I identified diverse …
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Neural response variability in the navigational system of the brain
… neural representations reminiscent of the head direction circuit, even when deterministic, and exhibit variability patterns that are similar when quantified with the UCM. These results suggest that rich variability patterns may simply arise as a byproduct of underlying circuit dynamics, …
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Representation of Whole-body Navigation in the Primary Sensorimotor and Premotor Cortex
… two-dimensional (2D) room</p><p>position and the direction of the wheelchair and the monkey head. The activities</p><p>of these cells were phenomenologically similar to place cells and head direction</p><p>(HD) cells found in rat hippocampus and entorhinal cortices. I observed 44.6%</p><p>and …
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Investigating the role of the hippocampal formation in episodic and spatial memory
… information regarding internal orientation and direction and this leads to the question assessed in the final part of this thesis of where this integration occurs. Based on anatomical evidence and the current literature, the postsubiculum, an input structure to the hippocampus, emerged as a …