Neural dynamics of attentional resource allocation in early visual cortex: emotional scenes produce competitive interactions.

Abstract

Salient emotional visual cues receive prioritized processing in human visual cortex. To what extent emotional facilitation relies on preattentional stimulus processing preceding semantic analysis remains controversial. Making use of steady-state visual evoke potentials frequency-tagged to meaningful complex emotional scenes and their scrambled versions, presented in a 4-Hz rapid serial visual presentation fashion, the current study tested temporal dynamics of semantic and emotional cue processing. The neural dynamics of bottom-up capture of attention driven by concrete images were analyzed under a passive-viewing-like scenario and in a competitive context, where a concurrent foreground task realized with a random dot kinematogram flickering at 15Hz enabled the concurrent monitoring of top-down selective attention. Aligned with the semantic primacy hypothesis, the steady-state visual evoke potentials' results provide evidence of an initial rapid capture of attention driven by objecthood, followed by heightened deployment of attentional resources to emotional scenes that remained stable for the entire stimulation period. We replicated previous findings in which emotional distractors first prompt visuocortical facilitation, followed by suppression of a concurrent foreground task. Modeling this time-delayed competition process fit the data better than a time-invariant trade-off between concurrent cues as assumed by most models of selective attention.