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 20 of 41 for “"Entorhinal cortex"”.
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Functional Connectivity of Entorhinal Cortex in Alzheimer's Disease
… disruption of cortical connections. The entorhinal cortex (EC) is a region of cortical gray matter in the medial temporal lobe important in memory processing, and has been identified as the first structure affected in AD. The current study investigated the functional connectivity of the …
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Circuitry and function of layer 1 interneurons in the medial entorhinal cortex
… One area in particular, called the medial entorhinal cortex (MEC), contains a high density of spatially-tuned cell types that are thought to be integral to a dynamic perception of location. These cells are mostly concentrated in the superficial layers of the MEC and have been well-studied …
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The function and structure of the entorhinal cortex in mild cognitive impairment
The function and structure of the entorhinal cortex in mild cognitive impairment Background: The entorhinal cortex (EC) is the first brain region to exhibit neurodegeneration in Alzheimer’s disease (AD). As such, tests of EC function may help aid detection of the disease in its earliest stages. …
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The effects of periodic and non-periodic inputs on the dynamics of a medial entorhinal cortex layer II stellate cell model
… Previous experimental work has shown that medial entorhinal cortex layer II stellate cells (SCs) exhibit sub-threshold and firing frequency resonance in the theta frequency band (4 - 10 Hz). In this thesis we seek to understand the biophysical and dynamic mechanism underlying these phenomena and …
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The Medial Entorhinal Cortex's role in temporal and working memory : characterization of a mouse lacking synaptic transmission in Medial Entorhinal Cortex Layer III
… This work here addresses the role of the medial entorhinal cortex layer III (MEC-III) to CA1 projections in episodic-like memory formation and recall. This circuit is addressed with a triple transgenic mouse which allows for the expression of tetanus toxin, an enzyme that disrupts synaptic …
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Amelioration of Alzheimer's Disease Pathology in 12-Month-Old hAPP(SweInd) Transgenic Mice After Treatment with a Cysteine Rich Whey Supplement, Immunocal®
… Given that Reelin-expressing neurons of the entorhinal cortex region are a highly vulnerable population of cells that are lost early in AD, we examined the effects of Immunocal® in the hippocampal-entorhinal cortex formation in a mouse model of AD. Glutathione levels and Reelin expression in …
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What’s in a cognitive map? Action representations in the hippocampal-entorhinal system
Spatially selective cell types in the mammalian entorhinal cortex are often taken as building blocks of a ‘cognitive map’, a mental representation of relational information. Nonetheless, relating these representations to behaviour, especially in non-spatial domains, has proven difficult. In this …
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Septotemporal Variation in Theta Rhythm Dynamics: Effects of Speed and Habituation
… across the septotemporal axis as well as in the entorhinal cortex. Our findings demonstrate the dominant relationship of speed to theta indices at septal sites. This relationship diminished systematically with distance from the septal pole of the hippocampus at both CA1 and DG sites. While theta …
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The impact of two spatial strategies on entorhinal and hippocampal involvement in visual path integration
… 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 virtual path completion task. While configural updating required allocentric encoding of the …
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From space to episodes : modeling memory formation in the hippocampal-neocortical system
… location- and direction-specific activity in the entorhinal cortex, all under neuromodulatory influence. In unfamiliar environments, mossy fiber inputs impose activity patterns on CA3, and recurrent collaterals and perforant path inputs are subject to graded Hebbian plasticity. Attractors are thus …
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Hippocampal Output to the Septum Regulates Locomotion and Exploration
… hand, activation of a subset of retrosplenial cortex-specific projecting DH INs or the entorhinal cortex-projecting DH neurons did not change animal locomotion. For the clinical application, targeting the DH-MSc inhibitory pathway can help us to determine the neuronal mechanisms of locomotion …
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Spatial and Conceptual navigation in Early Blind people: Testing the scaffolding hypothesis of cognitive maps
… easily accessible and reusable. The hippocampal-entorhinal system plays a crucial role in the creation of cognitive maps, and, particularly, grid cells have been targeted as the main neural correlate. In humans, grid-like activity has been associated with the encoding of both spatial and abstract …
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The Relationship Between Neuropsychological Functioning, Biomarker AV-1451, and Subjective Memory Impairment in a Cognitively Normal Sample
… of memory and level of tau binding in the entorhinal cortices and the hippocampi. It was further hypothesized that differences in memory would be mediated by level (high/low) of binding in these neuroanatomical structures. The sample included 127 cognitively normal (CN) participants, …
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Leptin induces a novel form of long-term potentiation at the direct cortical input to hippocampal CA1 synapses
… direct cortical input (perforant path) from the entorhinal cortex. Indeed, mounting evidence demonstrates that the direct cortical input is of importance to spatial learning and memory. Here we show that application of leptin induced a novel form of long-term potentiation (LTP) of excitatory …
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The Neural Substrates Supporting the Inhibition of Instrumental Avoidance Behavior
… hypothesis that the flow of information from the entorhinal cortex through the ventral subiculum to the nucleus accumbens is the pathway that mediates the suppression of conditioned responding in response to novel contextual cues during extinction of discriminative avoidance behavior. The results …
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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
… neurodegeneration is first observed in the entorhinal 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 …
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NeverMind : an interface for human Memory augmentation
… to passively stimulate the hippocampus, the entorhinal cortex, and the neocortex. Inspired by the methods currently used by memory champions, NeverMind facilitates memory encoding by engaging in hippocampal activation and promoting task-specific neural firing. NeverMind pairs spatial …
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Functional Connectivity of the Posterior Cingulate in Mild Cognitive Impairment and Alzheimer's Disease
… connectivity between the posterior cingulate cortex (PCC) and associated brain regions may make an important contribution in this regard, as changes in the PCC/precuneus and entorhinal cortex are implicated as early biomarkers for AD. The current study used functional connectivity magnetic …
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Hippocampal output to neocortex: Examination of the electrophysiological and plastic properties of CA1 projections to the perirhinal cortex
… long-term storage is believed to occur in the neocortex and the physiological mechanism underpinning this transfer of information is believed to be long-term changes in synaptic plasticity, namely long-term potentiation (LTP) and depression (LTD). The aim of this thesis is to characterise synaptic …
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Error correction in the hippocampal-medial-entorhinal cognitive map
Error correction in the hippocampal-medial-entorhinal cognitive map Tereza Vargová Summary Spatial navigation is a crucial skill for survival. The hippocampal-medial-entorhinal network contains multiple classes of spatially modulated cells, namely place cells, grid cells, border cells, and head …
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