Date of Award

Spring 1-1-2013

Document Type

Thesis

Degree Name

Master of Arts (MA)

Department

Psychology & Neuroscience

First Advisor

Marie T. Banich

Second Advisor

Tim Curran

Third Advisor

Randall C. O'Reilly

Abstract

Resting-state functional MRI (rs-fMRI) is thought to reflect the intrinsic functional organization of the brain. Studies of group differences in measures of rs-MRI are pervasive throughout the field of cognitive neuroscience and clinical neuropsychology, but the relationship between the resting state of the brain and individual differences in performance on psychological tasks in a normal population remains poorly understood. Moreover, the limited available research fails to adequately relate individual differences in the resting brain to theoretically motivated constructs that are thought to relate to underlying processes responsible for humans' ability to regulate thoughts and actions (i.e. - executive functions). Ninety-one college-aged participants completed a six-minute resting state fMRI scan and a battery of tasks measuring important aspects of executive function (see Miyake & Friedman, 2012): inhibition of a prepotent response (antisaccade task), task set shifting (category switching task), and working memory updating (keep-track task). Using Independent Components Analysis (ICA), we identified several networks of regions (Intrinsic Connectivity Networks, ICNs) with temporally correlated time courses. We found that 1. individuals who activated subsystems of the default network to a greater degree had higher common executive function and working memory updating and 2. individuals who activated right and left frontoparietal control network to a greater degree had higher task set shifting and working memory updating, respectively. Additional predictors of working memory updating were the degree to which individuals' left frontoparietal control ICN was negatively correlated with a subset of regions from the default mode ICN and also the degree to which individuals' right frontoparietal control ICN was positively correlated with a different subset of regions from the default mode ICN. Finally, we employed a recent methodology (Dual Regression) to explore areas associated with an ICN that covary with individual differences in executive function. Dual regression revealed that covariance of four regions along with ICNs predicted EF: increased presence of right anterior prefrontal cortex in the dmPFC subsystem of the default network predicted higher common EF, increased presence of left lateral parietal region in the right frontoparietal control network predicted higher task set shifting, and increased presence of left middle frontal gyrus and postero-medial prefrontal cortex in the left frontoparietal control network predicted higher working memory updating. The results of the current study have important implications for our understanding of executive function processes and individual differences in the brain at rest. In particular, we discuss how underlying brain processes responsible for executive function performance likely sculpt the intrinsic functional organization of the brain over time and to a different degree based on skill.

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