Functional Changes in the Motor Network Following Thalamotomy in Essential Tremor Patients using Seed-Based Resting-State Functional Magnetic Resonance Imaging
Date
2022-07-18
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Abstract
Motor network changes following magnetic resonance guided resonance imaging surgery (MRgFUS) in essential tremor (ET) are still poorly understood. The motor network dysfunction found in ET is hypothesized to originate from within the cortico-thalamo-cerebellar (CTC) network. Several methodologies of resting-state functional magnetic resonance imaging (rsfMRI) have been used to compare functional connectivity within these regions between ET patients and controls. Such methodologies include seed-based region of interest (ROI) analysis, independent component analysis and graph theory. To my knowledge, this is the first study to use seed-based rs-fMRI analysis to compare between longitudinal time-points in ET patients before and after MRgFUS thalamotomy and age- and sex-matched controls. Seed-to-voxel and ROI-to-ROI analysis were both used to study rs-fMRI in these groups. Although limited statistically significant differences were found between longitudinal time-points, more differences were observed when comparing between ET patients, pre- and post-surgery, and controls. It was found that pre-surgery ET patients had significantly increased functional connectivity between motor areas and occipital regions associated with visuospatial planning, compared to controls. This connectivity decreased immediately after surgery. A reduction in functional connectivity between basal ganglia regions and the motor cortices was also observed. These changes were transient however, because motor regions returned to increased connectivity with the occipital region, except for the left supplementary motor area (SMA), which continued to demonstrate decreased connectivity with the putamen at 3 months, compared to controls. These findings demonstrate that the motor network within ET may also entrain visual processing areas as well as the basal ganglia and that MRgFUS thalamotomy may alter functional connectivity to these areas.
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Keywords
Essential Tremor, High Intensity Focused Ultrasound, Magnetic Resonance Guided Focused Ultrasound (MRgFUS), Functional Magnetic Resonance Imaging (fMRI), Resting State, Seed-Based, Neuroscience
Citation
Specht, J. L. (2022). Functional Changes in the Motor Network Following Thalamotomy in Essential Tremor Patients using Seed-Based Resting-State Functional Magnetic Resonance Imaging (Master's thesis, University of Calgary, Calgary, Canada). Retrieved from https://prism.ucalgary.ca.