Dissertations, Theses, and Capstone Projects

Date of Degree

9-2020

Document Type

Thesis

Degree Name

M.S.

Program

Cognitive Neuroscience

Advisor

Mariann Weierich

Subject Categories

Cognitive Neuroscience | Psychology

Keywords

Resting-state fMRI, Diffusion imaging, Trauma

Abstract

The neurocircuitry model of posttraumatic stress disorder suggests an association between trauma-related symptoms and abnormalities in the structure and function of limbic and prefrontal brain regions. Evidence also suggests that these structural and functional abnormalities are related. We tested the relation between whole brain white matter integrity, resting-state functional connectivity of a fronto-limbic network, and trauma-related symptoms in 22 trauma-exposed women. We hypothesized that components of whole brain white matter would correlate with components of resting connectivity within a fronto-limbic network. We used parallel independent component analysis (pICA) to test the associations between whole brain fractional anisotropy (FA) maps and resting-state functional connectivity of a fronto-limbic network. We used components extracted from the pICA to predict individual scores on the Clinician-Administered PTSD Scale (CAPS). The pICA identified two independent components from the whole brain FA maps and two independent components from the resting fronto-limbic network, however these components were not significantly correlated across modalities. The two whole brain white matter components predicted a greater number of PTSD symptoms at a non-significant trend level (R2 =0.23, F(3,22)=1.75, p=0.193), and this relationship was driven by a component that represents increased FA of the forceps minor and forceps major. The two resting-state functional connectivity components also predicted greater number of PTSD symptoms at a non-significant trend level (R2=0.31, F(3,22)=2.69, p=0.077), and this relationship was driven by a component that represents increased resting connectivity within the orbitofrontal and subgenual cortices. Although pICA aims to identify related components across modalities, the components derived here were not significantly related across modalities. Our results suggest that trauma-related symptoms are associated with the structure of two interhemispheric tracts (medium effect size), and the function of a fronto-limbic network (large effect size), and additional analyses are required to further characterize the components extracted from the pICA. Further study of resting-state networks, integrity of pertinent white matter tracts, and their joint relation to trauma-related symptoms would provide a more comprehensive characterization of the mechanisms that underlie trauma-related symptoms. For this reason, multimodal methods such as data fusion represent a valuable tool for the study of trauma-related symptoms and associated structural and functional abnormalities.

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