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 19 of 19 for “"brain state"”.
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Impact of Brain State On Visual and Prefrontal Population Coding In Behaving Animals
<p>Patterns of neural activity in the brain constantly shift between different processing states. Earlier studies have established that the ongoing, spontaneous activity has major repercussions regarding how the brain processes incoming sensory stimuli. However, the interaction between behavioral …
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Defending the Multiple Realization Argument against the Identity Theory
… that the identity theory is false because mental state types are multiply realized in brain state types. In this dissertation I provide a detailed elaboration of the argument and a defense of it against a few of its prominent contemporary critics. Finally I offer empirical evidence from …
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Time-resolved Resting-state fMRI of Brain States Associated with Drug-resistant Epilepsy
… framework for time-resolved analysis of resting-state functional magnetic resonance imaging (fMRI) data with the aim of elucidating brain patterns of aberrant activity in individuals with drug-resistant epilepsy. Specifically, a dynamic functional connectivity analysis method is first used to …
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Low-Intensity Ultrasonic Neuromodulation of the Rat Hippocampus
<p>Techniques to non-invasively modulate brain activity are important for mapping human brain circuits, and also for the treatment of a host of neurological and psychiatric disorders marked by aberrant brain activity. Though a wide range of techniques for non-invasive neuromodulation have been …
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Influence of Pramipexole on Probability Discounting and Ventral Pallidal Function: Assessments in Parkinsonian-Like Rats
… of PD in this study to determine if a PD-like brain state alters the response of pramipexole in the discounting paradigm. The final series of studies focused on determining if a limbic brain region involved in reward-related behaviors is also altered by acute and/or chronic pramipexole …
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The Impact of Synchrony On Neuronal Coding and Behavior
… propagate within columnar circuits when the state of the brain changes remains poorly understood. We used multi-electrode laminar arrays to reveal that brain state modulates the propagation of neural activity across the layers of early and mid-level visual cortex (areas V1 and V4). We found a …
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Design and validation of chronic research tools for an implantable closed-loop neurostimulator
… today provide high frequency Deep Brain Stimulation (DBS) for therapeutic modulation of diseased neural circuits. These devices are approved for the treatment of Parkinson's Disease, Essential Tremor and Dystonia, and are in clinical evaluations for Epilepsy and Depression. Despite …
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Evaluating social and cognitive effects of video games using electroencephalography.
… games, using real-time data about the player’s brain state. This is particularly useful for game designers creating introductory tutorial mechanisms for their games. The result of this research is useful for both researchers investigating the human brain immersed in the virtual world of a video …
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Brain computer interface based neurorehabilitation technique using a commercially available EEG headset
… the therapeutic virtual or robotic movement. Brain Computer Interface (BCI) aims to open up a new rehabilitation option for clinical population having no residual movement due to disease or injury to the central or peripheral nervous system. Brain activity contains a wide variety of electrical …
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Neural dynamics of the anesthetized brain and the control of conscious states
… It is arguably the most powerful brain state manipulation that clinicians and researchers can reliably perform. However, the mechanisms underlying GA at the neural systems level are underexplored and largely not understood. To link neural dynamics to the loss of consciousness, we …
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Robust time-varying functional connectivity estimation and its relevance for depression
… (correlation between time series) between brain regions during a functional magnetic resonance imaging (fMRI) scan, and how it can be used as a lens through which to study depression as a functional disorder. Unfortunately, the field of TVFC is still riddled with uncertainty, especially …
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Neural correlates of trait mindfulness
There is a clear and present need to identify the brain biological bases of mental health and mental illness. In this thesis, I focus on the brain bases of trait mindfulness, measured using self-report. Mindful individuals pay attention to the present moment and bring an attitude of acceptance and …
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Dynamics and precursor signs for phase transitions in neural systems
This thesis investigates neural state transitions associated with sleep, seizure and anaesthesia. The aim is to address the question: How does a brain traverse the critical threshold between distinct cortical states, both healthy and pathological? Specifically we are interested in sub-threshold …
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Subcortical Inputs Governing Cortical Network Activity
… background activity, which varies by arousal state and behavioral context. Therefore, to understand how excitation propagates through the cortex, it is necessary to characterize the laminar flow of signal propagation as well as spontaneous network activity, which will constrain that …
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An Exploration of Neural Heterogeneity and its Consequences on Network Dynamics and Neuromodulation
… systems. This is especially true in the brain, where heterogeneity exists across all scales, from genetics and ion channel distribution to cell types and patterns of neuron connectivity. This heterogeneity has been linked to stable, persistent behaviour, increased information …
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Predicting and identifying signs of criticality near neuronal phase transition
… the critical transitions between distinct neural states associated with the transition to neuron spiking and with the induction of anaesthesia. First, mathematical and electronic models of a single spiking neuron are investigated, focusing on stochastic subthreshold dynamics on close approach to …
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The Impact of Cortical State On Neural Coding and Behavior
<p>The brain is never truly silent – up to 80% of its energy budget is expended during ongoing activity in the absence of sensory input. Previous research has shown that sensory neurons are not exclusively influenced by external stimuli but rather reflect interactions between sensory inputs and the …