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arXiv · 1501.04700

The paradoxical relationship of difficulty and lateral frontal cortex activity

Christopher H. Chatham·Nicole M. Long·David Badre
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Abstract

Task difficulty is widely cited in current theory regarding cognitive control and fronto-parietal function. Ongoing debate surrounds the extent to which global difficulty across multiple cognitive demands is the main driver of lateral frontal activity. Here, we examine a commonly cited behavioral marker of difficulty in these accounts: time-on-task (ToT), as assessed by response time. Specifically, we investigate the task-dependent scaling of frontal BOLD responses with ToT during hierarchical cognitive control. We observe a paradoxical relationship, whereby rostral regions show greater scaling with ToT on a first-order task, despite showing greater recruitment on a second-order task; caudal regions show the converse relationships. Together, these results demonstrate that ToT does not reflect a single dimension of difficulty that uniformly drives lateral frontal activity. Rather, this discrepancy in the mean and scaling of BOLD requires that multiple, distinct processes are instantiated across these fronto-parietal regions in the service of cognitive control function.

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Christopher H. Chatham, Nicole M. Long, David Badre. 2015-01-20. The paradoxical relationship of difficulty and lateral frontal cortex activity. https://arxiv.org/abs/1501.04700

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