Effective Connectivity Between Broca’s Area and Amygdala as a Mechanism of Top-Down Control in Worry

Abstract

Individuals higher in trait worry exhibit increased activation in Broca’s area during inhibitory processing tasks. To identify whether such activity represents an adaptive mechanism supporting top-down control, we investigated functional and effective connectivity of Broca’s area during a task of inhibitory control. Functional MRI data obtained from 106 participants performing an emotion-word Stroop task were examined using psychophysiological interaction and Granger causality (GC) analyses. Findings revealed greater directed connectivity from Broca’s area to amygdala in the presence of emotional distraction. Furthermore, a predictive relationship was observed between worry and the asymmetry in effective connectivity; worriers exhibited greater directed connectivity from Broca’s area to amygdala. When performing the task, worriers with greater GC directional asymmetry were more accurate than worriers with less asymmetry. Present findings indicate that individuals with elevated trait worry use a mechanism of top-down control in which communication from Broca’s area to amygdala fosters successful compensation for interference effects.