The neural cascading of early and late selection mechanisms in response to cognitive conflict

Abstract

Adaptive behaviors require the ability to solve conflict from processing incompatible sensory information. Competing models have been proposed to explain mechanisms underlying conflict resolutions. Early selection accounts suggest that conflict-induced cognitive interference is due to an additional step to focus attention on task-relevant sensory inputs while filtering out task-irrelevant distractors. Alternatively, late selection accounts posit that both behaviorally relevant and irrelevant sensory inputs receive full semantic analysis, leading to the recruitment of the frontal executive mechanisms to deal with conflict. While there is increasing evidence for the latter accounts, recent studies have directly tested the early selection accounts but a handful failed to provide positive findings. Here, we examined changes in the spatial scopes of attention in human subjects performing a variant of the Eriksen flanker tasks, where they discriminated the shape of the cued target surrounded by congruent or incongruent distractors. The spatial scopes of attention in the congruent and incongruent conditions were indexed by the spatial reconstructions based on the modeling of the alpha band activity (EEG oscillations at 8-12Hz), which have been shown to track the precise location of covert attention. We found that the scopes of the alpha-based spatial reconstructions were smaller in the incongruent conditions compared to those in the congruent conditions and these conflict-induced modulations occurred ~100-250 ms after stimulus onset. At the much later time window from ~400-600ms, we observed the increased midline-frontal negative-going event-related potential (ERP) thought to originate from the anterior cingulate cortex in response to conflict. Together, these results provide neural evidence implicating the essential role of early attentional selection in mitigating the conflicting sensory information at least in the context of our study and suggests that conflict resolution is supported by the cascade of neural processes that underlie the early selective attention and the frontal executive function, respectively.