Distribution of attention modulates salience signals in early visual cortex.

Manon Mulckhuyse,Durk Talsma,Dirk Heslenfeld,Artem V Belopolsky,Jan Theeuwes

doi:10.1371/journal.pone.0020379

Manon Mulckhuyse, Durk Talsma + Show 3 more

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https://doi.org/10.1371/journal.pone.0020379

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Abstract

Previous research has shown that the extent to which people spread attention across the visual field plays a crucial role in visual selection and the occurrence of bottom-up driven attentional capture. Consistent with previous findings, we show that when attention was diffusely distributed across the visual field while searching for a shape singleton, an irrelevant salient color singleton captured attention. However, while using the very same displays and task, no capture was observed when observers initially focused their attention at the center of the display. Using event-related fMRI, we examined the modulation of retinotopic activity related to attentional capture in early visual areas. Because the sensory display characteristics were identical in both conditions, we were able to isolate the brain activity associated with exogenous attentional capture. The results show that spreading of attention leads to increased bottom-up exogenous capture and increased activity in visual area V3 but not in V2 and V1.

Highlights

One of the most debated issues in selective attention research is whether we are able to exert full attentional control over what we select from our environment
The results showed that when attention was initially focused in the center there was no attentional capture while capture was observed when observers spread their attention across the visual field
This study shows that a salient irrelevant color singleton modulates visual processing in early visual areas

Summary

Introduction

One of the most debated issues in selective attention research is whether we are able to exert full attentional control over what we select from our environment. Because only distractors that matched the target color modulated the response, it was suggested that attentional modulation in extrastriate cortex was due to reentrant feedback signals from IPS and FEF signaling the spatial location and features of visual stimuli that match the current attentional set Note that in these studies capture by task-relevant distractors was examined. The study of De Fockert et al [37] examined bottom-up driven attentional processes, it did not report enhanced activity in early visual areas The design they used did not allow them to examine exogenously driven attentional sensory modulation of a salient stimulus without contrasting it with endogenously driven attentional modulation. We expected that attentional capture would be associated with a greater response in early visual areas at the corresponding retinotopic locations of the color singleton distractor

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Discussion