Browsing by Subject "Resting state"
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Item Functional Multimodal Imaging Of Sickle Cell Disease Patients To Understand How Chronic Pain Affects Neural Dynamics Of Patients(2018-05) Case, MichelleSickle cell disease (SCD) is a red blood cell disorder that causes many complications including life-long pain. Pain is the most common reason for hospitalization in SCD patients and is often experienced on a daily basis. Treatment of pain in SCD patients remains challenging due to a poor understanding of the mechanisms, especially in the brain. Therefore, an in-depth analysis of how chronic pain affects SCD patients is needed to provide a foundation for future research and improved treatment options. The goal of this research is to use multimodal non-invasive imaging techniques to better understand the neural dynamics of SCD patients and how these differ from a normal healthy brain. Utilizing both electroencephalography (EEG) and functional magnetic resonance imaging (fMRI) allowed spatiotemporal analysis of resting state neural behavior of SCD patients and healthy controls. This work includes (1) a simultaneous EEG-fMRI study to determine biomarkers of sickle pain and how resting state networks are altered in patients, (2) an EEG analysis utilizing EEG power and electrical source imaging analysis to classify between patients and controls, and (3) a graph theory study using both EEG and fMRI to understand the global impact of sickle pain on the brain and to utilize imaging to detect differences not only between patients and controls, but also between patients with more severe chronic pain and less severe chronic pain. This study showed how imaging parameters found from non-invasive imaging modalities are related to chronic pain in SCD patients and will be used in future work to guide new treatment options and validate their effectiveness on improving brain dynamics.Item Study of spontaneous bold fluctuation in animal and human brains(2010-09) Liu, XiaoSpontaneous blood-oxygen-level-dependent (BOLD) signals acquired at the resting state have recently been found to fluctuate coherently within many anatomically-connected and functionally-specific brain networks, and it may reflect an orderly organization of ongoing brain activity. Understanding this phenomenon may help us not only to understand some fundamental mechanisms of brain functions but also to find its applications in clinical field. However, the mechanisms underlying this phenomenon remains elusive, and even its neural origin is still controversial. This dissertation aimed to understand spontaneous BOLD fluctuation from its neurophysiological basis, its modulation under different brain states, and its role in brain functions. With five projects performed both on animals and humans, we have found that i) spontaneous BOLD fluctuation under deep burst-suppression anesthesia originates from underlying spontaneous neural activity, ii) spontaneous BOLD fluctuation is sensitive to changes in anesthesia depth, reflecting reorganization of ongoing brain activity at different consciousness level, iii) the resting-state visual network is spatially reorganized into activated and non-activated coherent network under continuous stimulation, and iv) the correlation strength within individuals' resting-state network can affect their evoked response to identical stimulations. These findings clearly support the functional significance of spontaneous BOLD fluctuation widely observed in animals and humans brain and provide new insights into its underlying mechanisms.