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 20 for “"Effective Connectivity"”.
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Bayesian population inference for effective connectivity
… the interaction between brain regions, termed effective connectivity, may be generalized beyond those subjects studied. The posterior density of population- and subject-level connectivity parameters is estimated in a Variational Bayesian (VB) framework, and structural model parameters are …
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Detecting Brain Effective Connectivity with Supervised and Bayesian Methods
… and an entire body of research, called brain effective connectivity, is devoted to detecting causal interactions between distinct brain areas. Brain effective connectivity is typically studied by the statistical analysis of direct measurements of the neural activity. The main purpose of this …
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Modelling Effective Connectivity in Functional Magnetic Resonance Imaging Data by State Space Models
… a new approach using state space models for effective connectivity analysis. The proposed approach integrates both activation and connectivity analysis into one single model. It takes the temporal information in the fMRI data into consideration explicitly and can be used to model the …
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The role of canalization in the spreading of perturbations in Boolean networks
… in random Boolean networks (BN) with homogeneous connectivity via numerical simulations. We consider two different measures of canalization introduced by Marques-Pita and Rocha, namely 'effective connectivity' and 'input symmetry,' in a three-pronged approach. First, we show that the mean …
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A Short Window Granger Causality Approach to Identify Brain Functional Pattern Associated with Changes of Performance Induced by Sleep Deprivation
… Recent research that has explored brain effective connectivity has demonstrated the directed inference interaction among pairs of brain areas, which may bring important insight to understand how brain works to support neurocognitive function. This research aimed to identify the brain …
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Hierarchical Bayesian Models for Multimodal Neuroimaging Data
… Second, we propose a multi-subject approach for effective connectivity inference using resting-state functional MRI data. The proposed method provides a joint, single-stage framework for multi-subject effective connectivity inference at both the subject- and group-levels. Furthermore, it accounts …
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Mechanistic Connectomics in Drosophila
… structure into the MB was then analysed. Random connectivity into the MB is thought to optimise memory formation. However, a random connectivity model does not accurately describe how second-order olfactory projection neurons (PNs) connect onto Kenyon Cells (KCs), the intrinsic neurons of the MB: …
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Functional organisation of behavioural inhibitory control mechanisms in cortico-basal ganglia circuitry: implications for stimulant use disorder.
… imaging (fMRI) revealed enhanced functional connectivity of the orbitofrontal and motor cortices as a correlate of flexible reversal learning performance, consistent with elevated levels of monoamines in these region (Chapter 3). Having clarified the mechanisms underlying behavioural …
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Temporal Dynamics of Endogenous and Stimulus-Driven Attention: Combined ECoG/fMRI Studies
… the excitability of task-relevant regions or the effective connectivity between them to enable selective neural processing of attended stimuli. Furthermore, different attention processes (holding vs. shifting attention) were associated with phase modulations at different frequencies, possibly to …
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Weaving the Past into an Imagined Future: Episodic Future Thinking Relies on Working Memory as a Cognitive Interface with Episodic Memory
… load control trials. Measures of functional and effective connectivity indicated that this behavioral effect corresponded with reduced coupling between the dorsomedial prefrontal cortex and right temporoparietal junction. Events imagined while simultaneously manipulating items in WM took longer …
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Computational Approaches To Epilepsy: Graph Networks For Localization And Multi-Model Approach For Prediction
… population-level signatures. By leveraging effective connectivity measures based on frequency-domain convergent cross-mapping (FD-CCM) and graph centrality, a robust model is developed. This approach is validated on challenging interictal recordings, demonstrating that integrating these …
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Electrophysiological Markers of Sensory Plasticity and Connectomics in Ageing and Mild Cognitive Impairment
… Coding. In addressing aim 1, the modulation of effective connectivity induced by these paradigms was compared. Consistent with their respective learning models, the MMN was associated with a modulation of both forward and backward connectivity in a fronto-temporal network, while visual …
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The Role of the Basal Ganglia in Memory and Motor Inhibition
… we found that both DLPFC and basal ganglia play effective roles to achieve inhibition in the task-specific regions (hippocampus for memory inhibition; primary motor cortex (M1) for motor inhibition). Specifically, memory inhibition requires a DLPFC-basal ganglia-hippocampus pathway, whereas motor …
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Top-Down Control of Lateral Interactions in Visual Cortex
… We hypothesized that top-down modulation of effective connectivity within V1 underlies the behaviorally dependent modulations of contextual interactions in V1. To test this idea, we used a chronically implanted multi-electrode array in awake primates and studied the mechanisms of top-down …
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Exploring Connectivity Patterns in Pediatric Encephalitis: An EEG-Based Connectivity Analysis
L'abstract è presente nell'allegato / the abstract is in the attachment
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Virtual reality visual feedback and its effect on brain excitability
… of activation, interhemispheric dominance, connectivity network of ipsilesional primary motor cortex (iM1) and the interhemispheric interaction between iM 1 and contralesional M1 (cM 1). After training, brain activity during a simple paretic hand movement is re-localized in terms of …
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Discerning nonlinear brain dynamics from EEG : an application to autistic spectrum disorder in young children
… could provide the basis for different brain connectivity, giving rise to macroscopic effects detectable by e.g. electroencephalography (EEG). A significant body of research has already been conducted in this direction, mainly computing spectral power and coherence. Perhaps due to …
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Development of the multi-scale dynamic modeling techniques for multi-modal brain recordings
… time scale (two weeks) without retraining. The effective connectivity defined from the presented model agrees with the established neuroanatomical hierarchy of motor control in the literature. I then introduced the m̲ulti-s̲cale n̲eural d̲ynamics n̲eural o̲rdinary d̲ifferential e̲quation …
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Development of novel multidimensional pattern-based EEG/MEG connectivity methods and their application to investigate the semantic brain network
Functional and effective connectivity methods are key to understanding how brain regions interplay to perform complex cognitive processes. Yet, most current connectivity methods summarise activity within brain regions to unidimensional measures, resulting in a loss of information. Only recently, …
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Brain Activation and Connectivity In Non-Disabled Multiple Sclerosis Patients
… recruitment is associated with alterations in connectivity in the working memory functional network. Patients exhibited similar network connectivity to that of control subjects when performing working memory tasks. We subsequently investigated the integrity of major white matter tracts to …