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.
Results
Showing 1 to 20 of 23 for “"cortical networks"”.
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Linking structure and function of complex cortical networks
… transmitting electrical information between cortical regions form a network which is neither regular nor completely random. Their structure seems to follow functional principles to balance between segregation (functional specialisation) and integration. Cortical regions are clustered into …
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Embedding of synchronous spike activity in cortical networks
… synfire chains are special feed-forward subnetworks that allow for stable modes of propagation of synchronous pulses of neuronal spike activity. These chains were previously investigated in isolation, with only a crudely simplified substrate of incoming background activity, with no feedback …
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Representational dynamics across multiple timescales in human cortical networks
Human cognition occurs at multiple timescales, including immediate processing of the ongoing experiences and slowly drifting higher-level thoughts. To understand how the brain selects and represents these various types of information to guide behavior, this thesis examined representational content …
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Learning temporal representations in cortical networks through reward dependent expression of synaptic plasticity
… neural mechanisms used by biological neural networks to learn temporal representations does not exist. It is commonly believed that the underlying cellular mechanisms reside in high order cortical regions and there is an ongoing debate about the neural structures required for temporal …
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Spatio-temporal dynamics of spontaneous neural activity during the transition from slow oscillations to an awake-like state in isolated cortical networks
… understood; in particular, the role of the local cortical network in orchestrating this transition spatially. We devised a new statistical procedure based on the time-frequency decomposi- tion of multivariate signals to investigate the network activity dynamics during this liminal regime. Our …
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The Impact of Cortical State On Neural Coding and Behavior
… brain. Yet, whether fluctuations in the state of cortical networks influence sensory coding in neural circuits and the behavior of the animal are unknown. To shed light on this issue, we conducted multi-unit electrophysiology experiments in visual areas V1 and V4 of behaving monkeys. First, we …
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Understanding Neural Burst Patterns Through Graph Neural Network Explainability in Simulated Neuronal Networks
Spontaneous bursting activity in neural networks represents a fundamental mode of informationprocessing in the brain, yet the mechanisms triggering these synchronized events remain poorly understood. While graph-based representations of neural networks are established, discovering the specific …
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Brain states and circuit mechanisms underlying sleep and general anesthesia
… subjects with optogenetic manipulation of thalamocortical circuits in mice to identify the neural dynamics underlying sleep and anesthesia. I first show that loss of consciousness during propofol general anesthesia is associated with the abrupt onset of slow oscillations that disrupt cortical …
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Spatial and Conceptual navigation in Early Blind people: Testing the scaffolding hypothesis of cognitive maps
… the grid system, as, instead, the typical cortical networks that support spatial and conceptual navigation show a high resiliency to early visual deprivation. These findings will deepen significantly our understanding of the relationship between spatial and nonspatial concepts, opening the …
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Functional connectivity of the speech network in relation to reading skill in school-age children
… Study to characterize functionally-defined cortical networks for speech in school-age children and investigate the relationship between speech network connectivity and reading skill development. The first study demonstrates the feasibility of using a task-based adult atlas of cortical speech …
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Early and Late Stage Mechanisms for Vocalization Processing in the Human Auditory System
… in human auditory cortices. Using fMRI, cortical representations of harmonic signal content were found along the middle superior temporal gyri between primary auditory cortices along Heschl's gyri and the superior temporal sulci, higher-order auditory regions. Additionally, …
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NEURAL MECHANISMS SUPPORTING COGNITIVE INFLUENCES ON SUPRASPINAL NOCICEPTIVE PROCESSING: INSIGHTS FROM BRAIN LESIONS
… cognitive information to directly influence cortical processing of nociceptive information. In contrast to studies that show attenuation or facilitation of incoming sensory information from the spinal cord, these supraspinal neural mechanisms may directly influence how nociceptive information …
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Population Coding In Laminar Cortical Circuits
… of sensory inputs is distributed across neuronal networks in cerebral cortex to influence sensory processing and behavioral performance. The fact that the structure of neuronal networks is organized according to cortical layers raises the possibility that sensory information could be processed …
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Perceptual Learning Of Object Shape
… shape occurs in early, retinotopically mapped cortical areas. fMRI work suggests that the learning of novel objects in this manner involves a reciprocal switch between two cortical networks, one that involves the normally object-sensitive regions of LOC, and one that involves the temporal and …
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The Functional architecture of language comprehension mechanisms : fundamental principles revealed with fMRI
… Using this approach, I first contrast two cortical networks engaged in comprehension: one, the "high-level language network", is selectively recruited by linguistic processing but not by other cognitive functions; another, the "multiple-demand network", is recruited across diverse cognitive …
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High-Resolution Diffusion Tensor Imaging and Human Brain Connectivity
… the organization of long and short-range cortical networks. However, the complexity of brain structure within an MRI voxel makes it difficult to dissociate the tissue origins of the measured anisotropy. The tensor characterization is a composite result of proton pools in different tissue …
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Dynamic speech networks in the brain: Dual contribution of incrementality and constraints in access to semantics
… the cognitive processes and relevant networks that come online prior to a word’s recognition point (e.g. “f” for butterfly) as we access meaning through speech in isolation. The results revealed that 300 ms before the word is recognised, the speech incrementally activated matching …
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Granular retrosplenial cortex layer 2/3 generates high frequency oscillation events coupled with hippocampal sharp wave-ripples and Str. LM high gamma
… processes within the hippocampus, and connected cortical networks, that recruit different circuit level dynamics to effectively process and pass information from brain region to brain region. In the hippocampal CA1 pyramidal layer local field potential (LFP), these processes take the form of …
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Characterising hippocampal replay in the APP<sup>NL-G-F</sup> mouse model of Alzheimer’s disease
… hippocampus can gradually be incorporated into cortical networks, a process known as system-level consolidation. Replay, the rapid recapitulation of neural sequences experienced during behaviour, is thought to be a key mechanism supporting consolidation and predominantly occurs during rest and …
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Complex networks in the climate system
… on pairs of grid points. The resulting climate networks are neither perfectly regular nor completely random, but display the intriguing and nontrivial characteristics of complexity commonly found in real world networks such as the internet, citation and acquaintance networks, food webs and …
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