Activation and Connectivity at the Decision and Execution Phases of a Voluntary Task Switching Paradigm
Derek M. Smith1, Eric H. Schumacher1; 1Georgia Institute of Technology
Recently voluntary task switching paradigms that separate the decision making and task execution phases of a trial have grown in terms of their representation in the literature. A simple version of such a task was carried out by subjects undergoing functional magnetic resonance imaging in order to evaluate task related activity and functional connectivity at the two phases. In order to separately model the decision and execution phases of the task both the interstimulus interval between the decision cue and the stimulus and the intertrial interval were jittered (50% 2 seconds, 25% 4 seconds, 25% 8 seconds). Significant reaction time switch cost and congruency effects were observed during the execution phase. Decisions to switch did not differ significantly in terms of decision cue reaction time from decisions to repeat. Contrasts demonstrated greater task related activation in anterior prefrontal cortex and the anterior cingulate cortex during both the execution and decision phases for switch relative to repeat trials. A beta series correlation analysis showed that during the decision phase the anterior prefrontal cortex was coupled with fellow members of the cingulo-opercular network, particularity the anterior cingulate, but it was also associated with some more posterior regions. These findings are marked by similar but distinct task related activity at different phases of a trial.
Topic Area: EXECUTIVE PROCESSES: Monitoring & inhibitory control