Conflict monitoring on an emotional Stroop task. Comparison of healthy older adults and patients with major neurocognitive disorders due to probable AD

Introduction: The conflict monitoring system exerts an influence on centers responsible for cognitive control, causing them to intervene more strongly in processing when conflict occurs. These mechanisms are usually investigated through specific tasks where there is an inherent interference elicited by the congruency or incongruency between the stimuli and responses, such as the Stroop task. In studies of emotional conflict, one hypothesis related to the dorsal anterior cingulate cortex (ACC) is that it serves, in part, to signal the appearance of conflicts, thus triggering compensatory adjustments. This study aims to verify whether the conflict monitoring hypothesis is confirmed in a group with Alzheimer's disease and, therefore, whether they exhibit a reduction in their reaction times. Method: A group of healthy older adults (HOA) and a group with Major Neurocognitive Disorders due to probable AD were evaluated to test the conflict monitoring hypothesis with an emotional Stroop task. Results: A significant interaction was obtained on the word and faces blocks. In the HOA group, a reduction in reaction times was observed, whereas in the AD groups, no reduction in reaction times was obtained. Conclusions: Whereas in HOA the conflict monitoring hypothesis is confirmed, in the Major Neurocognitive Disorders due to probable AD group there is no reduction in their reaction times on the high conflict resolution trials (incongruent trials that follow incongruent trials) due to their difficulty in making compensatory adjustments to cognitive control that help them to reduce conflict and improve their success rate.