A neural substrate of early response capture during conflict tasks in sensory areas

Studies that aim to understand the neural correlates of response conflicts commonly probe frontal brain areas associated with controlled inhibition and decision processes. However, untimely fast conflict errors happen even before these top-down processes are engaged. The dual-route model proposes that during conflict tasks, as soon as the stimulus is presented, two early processes are immediately at play. The task-relevant and task-irrelevant processes generate either compatible responses, when all stimulus features align, or incompatible responses, when stimulus features are in conflict. We aimed to find a neural substrate of these two processes by means of relating the quality of the representation of stimulus features in visual and somatosensory brain areas to responses in conflict tasks. Participants were scanned using fMRI while performing somatosensory and visual Simon tasks. The fMRI data were then analysed using a MVPA in early visual and somatosensory cortices. In agreement with our hypotheses, results suggest that the sensory representation of the task-relevant and task-irrelevant features drive erroneous trials. These results demonstrate that traces of response conflicts can arise already in sensory brain areas and that the quality of the representations in these regions can account for an early response capture by irrelevant stimulus features.