RESUMO
Attention and decision-making processes are fundamental to cognition. However, they are usually experimentally confounded, making it difficult to link neural observations to specific processes. Here we separated the effects of selective attention from the effects of decision-making on brain activity obtained from human participants (both sexes), using a two-stage task where the attended stimulus and decision were orthogonal and separated in time. Multivariate pattern analyses of multimodal neuroimaging data revealed the dynamics of perceptual and decision-related information coding through time (magnetoencephalography (MEG)), space (functional Magnetic Resonance Imaging (fMRI)), and their combination (MEG-fMRI fusion). Our MEG results showed an effect of attention before decision-making could begin, and fMRI results showed an attention effect in early visual and frontoparietal regions. Model-based MEG-fMRI fusion suggested that attention boosted stimulus information in frontoparietal and early visual regions before decision-making was possible. Together, our results suggest that attention affects neural stimulus representations in frontoparietal regions independent of decision-making.Significance statement Attention and decision-making processes are often experimentally confounded in neuroimaging studies, as participants are commonly asked to make categorical decisions about an attended stimulus only. Our study addresses this issue by separating the effects of selective attention from decision-making effects in human observers. We used multivariate pattern analyses to investigate the dynamics of perceptual and decision-related information coding through time (with MEG) and space (with fMRI) and applied a MEG-fMRI fusion analysis to combine data across neuroimaging modalities. Our results show that attention boosts stimulus information in frontoparietal and early visual regions before decision-making was possible. These findings provide an important verification of claims that attention modulates information processing in the brain and highlights the importance of separating these processes.