Protecting visual short-term memory during maintenance: Attentional modulation of target and distractor representations

Marlies E Vissers,Rasa Gulbinaite,Tijl Van Den Bos,Heleen A Slagter

doi:10.1038/s41598-017-03995-0

Abstract

In the presence of distraction, attentional filtering is a key predictor of efficient information storage in visual short-term memory (VSTM). Yet, the role of attention in distractor filtering, and the extent to which attentional filtering continues to protect information during post-perceptual stages of VSTM, remains largely unknown. In the current study, we investigated the role of spatial attention in distractor filtering during VSTM encoding and maintenance. Participants performed a change detection task with varying distractor load. Attentional deployment to target and distractor locations was tracked continuously by means of Steady-State Visual Evoked Potentials (SSVEPs). Analyses revealed that attention strongly modulated the amplitude of the second harmonic SSVEP response, with larger amplitudes at target compared to distractor locations. These attentional modulations commenced during encoding, and remained present during maintenance. Furthermore, the amount of attention paid to distractor locations was directly related to behavioral distractor costs: Individuals who paid more attention to target compared to distractor locations during VSTM maintenance generally suffered less from the presence of distractors. Together, these findings support an important role of spatial attention in distractor filtering at multiple stages of VSTM, and highlight the usefulness of SSVEPs in continuously tracking attention to multiple locations during VSTM.

Highlights

In the presence of distraction, attentional filtering is a key predictor of efficient information storage in visual short-term memory (VSTM)
Two additional participants showed no State Visual Evoked Potentials (SSVEPs) in the raw EEG data and were excluded from further SSVEP analyses
We examined the distribution of spatial attention across task-relevant and task-irrelevant locations during both encoding and maintenance stages of VSTM under conditions of high and low distractor load

Summary

Introduction

In the presence of distraction, attentional filtering is a key predictor of efficient information storage in visual short-term memory (VSTM). Recent studies show that attentional selection of goal relevant information does involve enhancement of goal-relevant sensory processing, and entails concurrent suppression of goal-irrelevant sensory processing[11,12,13] Reliance on these attentional mechanisms has been shown to vary across individuals as a function of working memory capacity (WMC). While current evidence for the role of attentional filtering during VSTM encoding is based on attentional modulation of task-irrelevant information[15], enhancement of processing of relevant information during VSTM has received less attention This renders it unclear if successful VSTM performance selectively relies on suppression of irrelevant sensory processing, or may involve enhancement of goal-relevant sensory processing[11,12,13, 16, 17]. Retro-cueing studies have revealed large effects of further attentional manipulations of stored representations on VSTM performance, it remains unclear to what extent attention plays a role during typical VSTM in the absence of attentional cues or novel distractors presented during VSTM delay

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