Tracking target and distractor processing in fixed-feature visual search: Evidence from human electrophysiology.

Attentional selection of a target presented among distractors can be indexed with an event-related potential (ERP) component known as the N2pc. Theoretical interpretation of the N2pc has suggested that it reflects a fundamental mechanism of attention that shelters the cortical representation of targets by suppressing neural activity stemming from distractors. Results from fields other than human electrophysiology, however, suggest that attention does not act solely through distractor suppression; rather, it modulates the processing of both target and distractors. We conducted four ERP experiments designed to investigate whether the N2pc reflects multiple attentional mechanisms. Our goal was to reconcile ostensibly conflicting outcomes obtained in electrophysiological studies of attention with those obtained using other methodologies. Participants viewed visual search arrays containing one target and one distractor. In Experiments 1 through 3, the distractor was isoluminant with the background, and therefore, did not elicit early lateralized ERP activity. This work revealed a novel contralateral ERP component that appears to reflect direct suppression of the cortical representation of the distractor. We accordingly name this component the distractor positivity (PD). In Experiment 4, an ERP component associated with target processing was additionally isolated. We refer to this component as the target negativity (NT). We believe that the N2pc reflects the summation of the PD and NT, and that these discrete components may have been confounded in earlier electrophysiological studies. Overall, this study demonstrates that attention acts on both target and distractor representations, and that this can be indexed in the visual ERP.

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Drawn to Distraction: Anxiety Impairs Neural Suppression of Known Distractor Features in Visual Search

Journal of Cognitive Neuroscience ◽

10.1162/jocn_a_01743 ◽

2021 ◽

pp. 1-13

Author(s):

Christine Salahub ◽

Stephen M. Emrich

Keyword(s):

Visual Search ◽

Attentional Control ◽

Template Matching ◽

Time Course ◽

High Anxiety ◽

Guided Search ◽

Distractor Processing ◽

Search And Destroy

Abstract When searching for a target, it is possible to suppress the features of a known distractor. This suppression may prevent distractor processing altogether or only after the distractor initially captures attention (i.e., search and destroy). However, suppression may be impaired in individuals with attentional control deficits, such as in high anxiety. In this study (n = 48), we used ERPs to examine the time course of attentional enhancement and suppression when participants were given pretrial information about target or distractor features. Consistent with our hypothesis, we found that individuals with higher levels of anxiety had lower neural measures of suppressing the template-matching distractor, instead showing enhanced processing. These findings indicate that individuals with anxiety are more likely to use a search-and-destroy mechanism of negative templates—highlighting the importance of attentional control abilities in distractor-guided search.

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Theta Oscillations Modulate Attentional Search Performance Periodically

Journal of Cognitive Neuroscience ◽

10.1162/jocn_a_00755 ◽

2015 ◽

Vol 27 (5) ◽

pp. 945-958 ◽

Cited By ~ 40

Author(s):

Laura Dugué ◽

Philippe Marque ◽

Rufin VanRullen

Keyword(s):

Visual Search ◽

Early Stage ◽

Phase Locking ◽

Occipital Cortex ◽

Periodic Pattern ◽

Search Performance ◽

Oscillatory Phase ◽

Successful Search ◽

Brain States ◽

Human Electrophysiology

Visual search—finding a target element among similar-looking distractors—is one of the prevailing experimental methods to study attention. Current theories of visual search postulate an early stage of feature extraction interacting with an attentional process that selects candidate targets for further analysis; in difficult search situations, this selection is iterated until the target is found. Although such theories predict an intrinsic periodicity in the neuronal substrates of attentional search, this prediction has not been extensively tested in human electrophysiology. Here, using EEG and TMS, we study attentional periodicities in visual search. EEG measurements indicated that successful and unsuccessful search trials were associated with different amounts of poststimulus oscillatory amplitude and phase-locking at ∼6 Hz and opposite prestimulus oscillatory phase at ∼6 Hz. A trial-by-trial comparison of pre- and poststimulus ∼6 Hz EEG phases revealed that the functional interplay between prestimulus brain states, poststimulus oscillations, and successful search performance was mediated by a partial phase reset of ongoing oscillations. Independently, TMS applied over occipital cortex at various intervals after search onset demonstrated a periodic pattern of interference at ∼6 Hz. The converging evidence from independent TMS and EEG measurements demonstrates that attentional search is modulated periodically by brain oscillations. This periodicity is naturally compatible with a sequential exploration by attention, although a parallel but rhythmically modulated attention spotlight cannot be entirely ruled out.

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Working memory availability affects neural indices of distractor processing during visual search

10.1101/295378 ◽

2018 ◽

Cited By ~ 1

Author(s):

Dion T. Henare ◽

Jude Buckley ◽

Paul M. Corballis

Keyword(s):

Working Memory ◽

Visual Search ◽

Memory Load ◽

Individual Performance ◽

Event Related Potential ◽

Neural Mechanisms ◽

Human Cognition ◽

Working Memory Load ◽

Distractor Processing ◽

Selective Processing

AbstractWorking memory and selective attention are traditionally viewed as distinct processes in human cognition. However, increasing research demonstrates significant overlap between these constructs such that as working memory availability decreases, individuals perform worse on attention-based tasks. To date, the neural mechanisms involved in this interaction are unknown. We measured three candidate lateralized event-related potential components (N2pc, Ptc, and SPCN) to observe the effects of increased working memory load on selective processing of targets and distractors. We found that increased working memory load impaired the processing of distractors, but not targets, and this was reflected in attentuation of the Ptc to distractors. We also found that individual performance on the task is related to the neural response to both targets and distractors. This study suggests that working memory availability impacts individuals’ ability to disengage from irrelevant stimuli, and that individual differences in visual search ability under load are related to both target and distractor processing.

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Parallel fast and slow recurrent cortical processing mediates target and distractor selection in visual search

Communications Biology ◽

10.1038/s42003-020-01423-0 ◽

2020 ◽

Vol 3 (1) ◽

Author(s):

Sarah E. Donohue ◽

Mircea A. Schoenfeld ◽

Jens-Max Hopf

Keyword(s):

Visual Cortex ◽

Visual Search ◽

Electric Fields ◽

Neural Correlates ◽

Opposite Polarity ◽

Exact Nature ◽

Behavioral Performance ◽

Distractor Processing ◽

Reentrant Processing

AbstractVisual search has been commonly used to study the neural correlates of attentional allocation in space. Recent electrophysiological research has disentangled distractor processing from target processing, showing that these mechanisms appear to operate in parallel and show electric fields of opposite polarity. Nevertheless, the localization and exact nature of this activity is unknown. Here, using MEG in humans, we provide a spatiotemporal characterization of target and distractor processing in visual cortex. We demonstrate that source activity underlying target- and distractor-processing propagates in parallel as fast and slow sweep from higher to lower hierarchical levels in visual cortex. Importantly, the fast propagating target-related source activity bypasses intermediate levels to go directly to V1, and this V1 activity correlates with behavioral performance. These findings suggest that reentrant processing is important for both selection and attenuation of stimuli, and such processing operates in parallel feedback loops.

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Spatial filtering during visual search: Evidence from human electrophysiology.

Journal of Experimental Psychology Human Perception & Performance ◽

10.1037/0096-1523.20.5.1000 ◽

1994 ◽

Vol 20 (5) ◽

pp. 1000-1014 ◽

Cited By ~ 485

Author(s):

Steven J. Luck ◽

Steven A. Hillyard

Keyword(s):

Visual Search ◽

Spatial Filtering ◽

Human Electrophysiology

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Dynamics of target and distractor processing in visual search: Evidence from event-related brain potentials

Neuroscience Letters ◽

10.1016/j.neulet.2011.03.064 ◽

2011 ◽

Vol 495 (3) ◽

pp. 196-200 ◽

Cited By ~ 26

Author(s):

Matthew R. Hilimire ◽

Jeffrey R.W. Mounts ◽

Nathan A. Parks ◽

Paul M. Corballis

Keyword(s):

Visual Search ◽

Brain Potentials ◽

Distractor Processing

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The “red-alert” effect in visual search: Evidence from human electrophysiology

Psychophysiology ◽

10.1111/psyp.12050 ◽

2013 ◽

Vol 50 (7) ◽

pp. 671-679 ◽

Cited By ~ 27

Author(s):

Ulysse Fortier-Gauthier ◽

Roberto Dell'Acqua ◽

Pierre Jolicœur

Keyword(s):

Visual Search ◽

Human Electrophysiology

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Inhibition of Return in the Covert Deployment of Attention: Evidence from Human Electrophysiology

Journal of Cognitive Neuroscience ◽

10.1162/jocn.2009.21042 ◽

2009 ◽

Vol 21 (4) ◽

pp. 725-733 ◽

Cited By ~ 34

Author(s):

John J. McDonald ◽

Clayton Hickey ◽

Jessica J. Green ◽

Jennifer C. Whitman

Keyword(s):

Visual Search ◽

Inhibition Of Return ◽

Search Task ◽

Visual Search Task ◽

Parietal Lobe ◽

Visual Environment ◽

Neural Processing ◽

Inhibitory Processes ◽

Human Electrophysiology ◽

The Right

People are slow to react to objects that appear at recently attended locations. This delay—known as inhibition of return (IOR)—is believed to aid search of the visual environment by discouraging inspection of recently inspected objects. However, after two decades of research, there is no evidence that IOR reflects an inhibition in the covert deployment of attention. Here, observers participated in a modified visual-search task that enabled us to measure IOR and an ERP component called the posterior contralateral N2 (N2pc) that reflects the covert deployment of attention. The N2pc was smaller when a target appeared at a recently attended location than when it appeared at a recently unattended location. This reduction was due to modulation of neural processing in the visual cortex and the right parietal lobe. Importantly, there was no evidence for a delay in the N2pc. We conclude that in our task, the inhibitory processes underlying IOR reduce the probability of shifting attention to recently attended locations but do not delay the covert deployment of attention itself.

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