Novel Functional Magnetic Resonance Imaging Analysis Approaches for Investigations of the Dynamics of Resting-State Functional Connectivity

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dc.contributor.advisorGoodyear, Bradley G.
dc.contributor.authorSojoudi, Alireza
dc.contributor.committeememberSmith, Michael Richard
dc.contributor.committeememberDukelow, Sean P.
dc.contributor.committeememberMacIntosh, Bradley
dc.contributor.committeememberMacMaster, Frank P.
dc.contributor.committeememberSotero Díaz, Roberto
dc.date2018-11
dc.date.accessioned2018-08-27T15:46:13Z
dc.date.available2018-08-27T15:46:13Z
dc.date.issued2018-08-23
dc.description.abstractSpontaneous fluctuations of blood-oxygenation level-dependent functional magnetic resonance imaging (BOLD fMRI) signals are highly synchronous between brain regions that serve similar functions. This provides a means to investigate functional networks of the human brain; however, most data analysis techniques assume functional connections are constant over time. This is problematic when studying brain processes associated with aging or neurological disease, where functional connections may become highly variable. Proposed methods of examining moment-to-moment changes in the strength of functional connections over an imaging session (so called dynamic connectivity) are not well established, and there are several pitfalls in current analysis approaches. In this thesis, novel analysis frameworks are developed to address several issues associated with dynamic resting-state fMRI analysis techniques. These techniques are then used to analyze the dynamics of functional connectivity within long-range and local brain networks. Specifically, a hierarchical observation modeling approach is proposed to permit statistical inference of the presence of dynamic connectivity at any point in time. Also, a sliding-window regional homogeneity approach is developed to examine the dynamics of local functional connectivity, to gain even further insight into the global functional organization of the human brain. Finally, the proposed methods are used in a study to determine resting-state local and long-range connectivity changes related to healthy aging, and further, how these changes demonstrate that age changes the proportion of time the brain occupies certain functional states. The studies in this thesis greatly further our understanding of the functional architecture of the human brain, in terms of how local and long-distance interactions are organized both in space and time. This thesis also helps establish a framework for dynamic resting-state fMRI analysis with consistency and reliability.en_US
dc.identifier.citationSojoudi, A. (2018). Novel Functional Magnetic Resonance Imaging Analysis Approaches for Investigations of the Dynamics of Resting-State Functional Connectivity (Doctoral thesis, University of Calgary, Calgary, Canada). Retrieved from https://prism.ucalgary.ca. doi:10.11575/PRISM/32843en_US
dc.identifier.doihttp://dx.doi.org/10.11575/PRISM/32843
dc.identifier.urihttp://hdl.handle.net/1880/107663
dc.language.isoeng
dc.publisher.facultyGraduate Studies
dc.publisher.facultySchulich School of Engineering
dc.publisher.institutionUniversity of Calgaryen
dc.publisher.placeCalgaryen
dc.rightsUniversity of Calgary graduate students retain copyright ownership and moral rights for their thesis. You may use this material in any way that is permitted by the Copyright Act or through licensing that has been assigned to the document. For uses that are not allowable under copyright legislation or licensing, you are required to seek permission.
dc.subjectfunctional MRI
dc.subjectdynamic functional connectivity
dc.subjecthierarchical observation modeling
dc.subjectregional homogeneity
dc.subjectBayesian inference
dc.subject.classificationEngineering--Biomedicalen_US
dc.titleNovel Functional Magnetic Resonance Imaging Analysis Approaches for Investigations of the Dynamics of Resting-State Functional Connectivity
dc.typedoctoral thesis
thesis.degree.disciplineBiomedical Engineering
thesis.degree.grantorUniversity of Calgary
thesis.degree.nameDoctor of Philosophy (PhD)
ucalgary.item.requestcopytrue
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