Psychology ETDs

Publication Date

Spring 4-17-2017

Abstract

We proposed a novel measure of conceptualizing dynamic functional network connectivity (FNC) in the human brain using flexibility of functional connectivity (fFC), which captures the variance of functional connectivity across time. In task-free fMRI scans (N = 122), this measure was demonstrated to correspond to the underlying structural connectivity (SC) within the default mode network (DMN), while static functional connectivity (sFC) did so to a relatively low degree. As SC likely does not develop to facilitate task-free brain function, but rather to integrate information during cognitive engagement, we argue that fFC can estimate the potential functional connectivity exhibited outside of the task-free setting to a greater degree than sFC, and is better suited for examining behavioral correlates of FNC. In support of this, we showed that SC-fFC coupling was related to intelligence levels, while SC-sFC coupling was not. Further, we found that the DMN existed in a functionally disconnected state during a large portion of the scan, raising questions about whether sFC is a meaningful quantifier of functional connectivity in the absence of a task, and scrutinizing its extrapolative power to real-world, cognitively engaging scenarios. Given that fFC is based on FNC variability across time rather than its average, it is largely unaffected by such contaminants.

Degree Name

Psychology

Level of Degree

Doctoral

Department Name

Psychology

First Committee Member (Chair)

Claudia D. Tesche

Second Committee Member

James F. Cavanagh

Third Committee Member

Derek A. Hamilton

Fourth Committee Member

Robert J. Thoma

Language

English

Keywords

Default Mode Network, Functional Connectivity, Structural Connectivity, Functional Networks, fMRI, DTI

Document Type

Dissertation

Download

Share

COinS