Differential and overlapping effects between exogenous and endogenous attention shape perceptual facilitation during visual processing

Abstract

Visuospatial attention is not a monolithic process and can be divided into different functional systems. In this framework, exogenous attention reflects the involuntary orienting of attention resources following a salient event, whereas endogenous attention corresponds to voluntary orienting based on the goals and intentions of individuals. Previous work shows that these attention processes map onto distinct functional systems, yet evidence suggests that they are not fully independent. In the current work, we investigated the differential and overlapping effects of exogenous and endogenous on visual processing of sensory events. Specifically, we combined spatial cueing of visuospatial attention, electroencephalography (EEG), and multivariate pattern analysis (MVPA) to examine where and when the effects of exogenous and endogenous attention were maximally different and maximally similar. Critically, MVPA provided new insights by examining whether classifiers trained to decode the cueing effect for one attention process (e.g., exogenous attention) can successfully decode the cueing effect for the other attention process (e.g., endogenous attention), and vice versa. These analyses revealed differential effects between exogenous and endogenous early after target onset (<200ms post-target). In turn, both shared similar processing later (~300ms post-target). We combined principal component analyses, single-trial event-related potentials, and mediation analysis to determine whether these effects contribute to the facilitation effects observed at the behavioral level after exogenous and endogenous spatial cueing. We uncovered that three EEG components (i.e., a posterior ipsilateral component, a posterior contralateral one, and a central one) shape the cueing effects of exogenous and endogenous attention at various times after target onset. Altogether, our study combines the strengths of MVPA, single-trial analysis, and meditation modelling to provide a comprehensive account about overlapping and differential processes of endogenous and exogenous, and how these dynamics relate to perceptual facilitation in the context of visuospatial attention.