Poster B35, Sunday, March 26, 8:00 – 10:00 am, Pacific Concourse
Investigating the Functional Structure and Dynamics of the Prefrontal Cortex
Savannah Cookson1,2, Eric Schumacher1; 1Georgia Institute of Technology, 2University of California, Berkeley
Prefrontal cortex (PFC) is involved in many cognitive processes important for complex, flexible human behavior (Duncan & Owen, 2000). Recent research has posited two axes of functional organization in PFC – a rostrocaudal axis (Badre 2008) and a dorsoventral axis (O'Reilly, 2010) – and suggested a possible interaction between the two. However, it remains unclear what underlies this apparent interaction, and how this may relate to other PFC organizing principles. The present experiment aimed to address these questions in a novel “hierarchical precuing” task that combined a traditional cuing procedure with a hierarchical mapping structure. Participants made one of four possible judgments about pairs of stimuli based on simple featural characteristics shared by the pair. Two judgments related to spatial features of the stimuli, and two to nonspatial features. One spatial and one nonspatial judgment was mapped to each hand. Cues presented at the start of each trial allowed for preparation at different levels of complexity. We then analyzed fMRI data recorded during task execution to investigate how different combinations of cue information, task processing domain, and response hand interacted to influence the distribution of activity within a set of regions of interest. Importantly, the timing of our task allowed us to independently analyze activity at the cue and the stimulus, separating preparation and execution activity. We found that the three manipulations revealed organizational activity patterns that developed differently from the cue to the stimulus event, suggesting that PFC functional organization may change dynamically based on immediate task demands.
Topic Area: EXECUTIVE PROCESSES: Goal maintenance & switching