Sustained neural mechanisms of proactive control in a novel task-switching color-word Stroop fMRI paradigm

Poster Session A - Saturday, April 13, 2024, 2:30 – 4:30 pm EDT, Sheraton Hall ABC

Maya Quale¹ (mayaq@wustl.edu), Thomas Dudey¹, Joset Etzel¹, Julie Bugg¹, Todd Braver¹; ¹Washington University in Saint Louis

The color-word Stroop task is one of the most widely studied paradigms for investigating cognitive control, yet the neural mechanisms that enable individuals to meet the control demands of incongruent trials are still poorly understood. We have utilized the Dual Mechanisms of Control (DMC) theoretical framework to suggest that Stroop interference can be flexibly regulated by either proactive or reactive control mechanisms. In prior work, we found evidence of reactive control in terms of a consistent reduction in event-related activity among 35 parcels within the fronto-parietal and cingulo-opercular networks. Here, we utilize a novel vocal response fMRI design which intermixes Stroop color naming and word reading blocks and manipulates proportion congruency across scanning runs, while holding diagnostic stimuli constant, to orthogonally vary proactive and reactive control. In preliminary results from our on-going study (current N=20), we replicate prior findings that Stroop interference is stronger in color naming than word reading, and that list-wise proportion congruent blocks impact proactive control behavioral indices, while item-specific proportion congruent blocks impact reactive control indices. In the same set of 35 prespecified fronto-parietal and cingulo-opercular parcels, clear event-related incongruency effects are observed, but do not differentiate between color naming and word reading or proactive and reactive control. In contrast, sustained activity in these regions is significantly and selectively increased during proactive color naming blocks. These results support prior hypotheses associating proactive control with sustained activation, while suggesting that such effects may be more prominent when the color naming task-set is salient (i.e., task-switching conditions).

Topic Area: EXECUTIVE PROCESSES: Goal maintenance & switching