RT Journal Article
SR Electronic
T1 The time-course of component processes of selective attention
JF bioRxiv
FD Cold Spring Harbor Laboratory
SP 511022
DO 10.1101/511022
A1 Tanya Wen
A1 John Duncan
A1 Daniel J Mitchell
YR 2019
UL http://biorxiv.org/content/early/2019/01/10/511022.abstract
AB Attentional selection shapes human perception, enhancing relevant information, according to behavioral goals. Here, we used multivariate decoding of electrophysiological brain responses (MEG/EEG) to examine real-time representation of the component processes of selective attention. Auditory cues instructed participants to respond to a particular visual target, embedded within a stream of single- and multi-item displays. Although the task logically required items to be compared to an attentional “template”, signals consistent with such a template were relatively weak and appeared to transition through a quiescent state. Subsequent stimulus processing evoked strong neural representation of multiple target features, evolving over different timescales. Combining single and multi-item displays with different types of distractors allowed quantification of various components of attention. Following a visual choice display, we observed five distinguishable processing operations with different time-courses. First, visual properties of the stimulus were strongly represented. Second, the location of the candidate target was rapidly represented in multi-item displays, providing the earliest evidence of modulation by behavioral relevance. Third, there was enhanced representation of the candidate target, including its identity, relative to distractors. Fourth, only later was the behavioral significance of the target explicitly represented in single-item displays. Finally, if the target was not identified and search was to be resumed, then an attentional template was weakly reactivated. The observation that an item’s behavioral relevance directs attention in multi-item displays prior to explicit representation of target/non-target status in single-item displays is consistent with two-stage models of attention.Significance Statement Imagine looking for a friend in a crowd. Visual search starts from an internal template of the target, and attentional selection enhances representation of information consistent with the target. This study examined the component processes of attentional selection using MEG/EEG. Preparatory representation of an upcoming target was weak. The choice display then evoked distinct representations of visual features, target location, target identity, and behavioral significance, each with a characteristic time-course. Intriguingly, evidence of directed attention to a target appeared earlier than explicit categorization of a single stimulus. Multiple processes of selective visual attention can be robustly decoded from MEG/EEG signals.This work was supported by funding from the Medical Research Council (United Kingdom), program SUAG/002/RG91365. TW was supported by the Taiwan Cambridge Scholarship from the Cambridge Commonwealth, European & International Trust and the Percy Lander studentship from Downing College.