Thinking Under Pressure: How Acute Stress Modulates Dorsolateral Prefrontal and Anterior Cingulate Cortex Activation

Acute stress is proposed to impair prefrontal cognitive control, yet most neuroimaging studies treat stress as a binary state, leaving unclear how graded increases in stress modulate conflict-related brain activity. This fMRI study investigated how escalating acute stress affects activation in two key control regions—the dorsolateral prefrontal cortex (DLPFC) and anterior cingulate cortex (ACC)—during cognitive conflict. Nine healthy adults performed the Leiden Stroop-like Stress Task (LSST), which systematically increased stress across four blocks by combining time pressure, task uncontrollability, and social-evaluative threat. We tested whether incongruent > congruent activation would emerge in DLPFC and ACC, whether ACC conflict signals would increase linearly with stress, and whether DLPFC conflict activation would decrease. Small-volume–corrected ROI analyses showed that right DLPFC responded more to incongruent than congruent trials, whereas a left middle frontal cluster...Show moreAcute stress is proposed to impair prefrontal cognitive control, yet most neuroimaging studies treat stress as a binary state, leaving unclear how graded increases in stress modulate conflict-related brain activity. This fMRI study investigated how escalating acute stress affects activation in two key control regions—the dorsolateral prefrontal cortex (DLPFC) and anterior cingulate cortex (ACC)—during cognitive conflict. Nine healthy adults performed the Leiden Stroop-like Stress Task (LSST), which systematically increased stress across four blocks by combining time pressure, task uncontrollability, and social-evaluative threat. We tested whether incongruent > congruent activation would emerge in DLPFC and ACC, whether ACC conflict signals would increase linearly with stress, and whether DLPFC conflict activation would decrease. Small-volume–corrected ROI analyses showed that right DLPFC responded more to incongruent than congruent trials, whereas a left middle frontal cluster showed the opposite pattern, indicating functional heterogeneity. No significant conflict-related activation emerged in ACC. Contrary to predictions, neither ROI-based nor whole-brain analyses showed a linear increase in ACC conflict signals or a decrease in DLPFC activation with rising stress. Instead, exploratory linear-trend analyses indicated increasing conflict-related activation over blocks in bilateral DLPFC and a broader fronto-parietal network. These findings suggest that under graded but manageable acute stress, cognitive control can be maintained—and even upregulated—via enhanced DLPFC recruitment rather than the anticipated prefrontal “shutdown.” The lack of clear ACC modulation may reflect task-specific factors (e.g., frequent, predictable conflict) and highlights the value of graded stress paradigms for probing adaptations in cognitive control networks.Show less

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Thinking Under Pressure: How Acute Stress Modulates Dorsolateral Prefrontal and Anterior Cingulate Cortex Activation