Name: Yunji Lee

Dissertation Defense Meeting

Date: November 17, 2025

Time: 3:00 PM

Location: https://gatech.zoom.us/j/6044346598

Dissertation Chairs/Advisor:

Eric Schumacher, Ph.D. (Georgia Tech)

Dissertation Committee Members:

Mark Wheeler, Ph.D. (Georgia Tech)

Thackery Brown, Ph.D. (Georgia Tech)

Shella Keilholz, Ph.D. (Emory University/ Georgia Tech)

Eliot Hazeltine, Ph.D. (University of Iowa)

Title: Dynamics of Brain Networks Underlying Cognitive Control in Conflict Tasks

Abstract: Cognitive control, the ability to integrate our thoughts and actions to achieve goal-directed behavior, is often assessed using conflict tasks, which evoke cognitive conflict from competing task information. Slower and more error-prone responses on incongruent compared to congruent trials reflect inhibitory attentional control. Previous fMRI research shows that three key brain networks are involved in overcoming conflict: the frontoparietal network (FPN), the dorsal attention network (DAN), and the ventral attention network (VAN). Additionally, the anti-correlation between these attentional control networks and the default mode network (DMN) plays an important role. To capture the dynamics of brain networks, the present study employed Co-Activation Pattern (CAP) analysis to prime-probe task fMRI data. The CAP results indicate two distinct functional modules: an FPN-DAN mode, associated with more goal-directed, task-oriented processing, and a DMN-VAN mode, which reflects the interplay of internal processing and salience detection. Trials with conflict exhibit more diverse CAPs compared to congruent trials, suggesting greater network flexibility under conflict resolution. By integrating these dynamic patterns of brain network coactivations, the present study provides a deeper understanding of the neural mechanisms underlying attentional control during conflict processing.