Spatial filtering during visual search: Evidence from human electrophysiology.

1994 ◽  
Vol 20 (5) ◽  
pp. 1000-1014 ◽  
Author(s):  
Steven J. Luck ◽  
Steven A. Hillyard
Keyword(s):  
Visual Search ◽  
Spatial Filtering ◽  
Human Electrophysiology

Theta Oscillations Modulate Attentional Search Performance Periodically

2015 ◽  
Vol 27 (5) ◽  
pp. 945-958 ◽  
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.

scholarly journals ZapLine: a simple and effective method to remove power line artifacts

2019 ◽  
Author(s):  
Alain de Cheveigné
Keyword(s):  
Local Field ◽  
Local Field Potentials ◽  
Real Data ◽  
Spatial Filtering ◽  
Power Line ◽  
New Method ◽  
Field Potentials ◽  
Simple Method ◽  
Multichannel Data ◽  
Human Electrophysiology

AbstractPower line artifacts are the bane of animal and human electrophysiology. A number of methods are available to help attenuate or eliminate them, but each has its own set of drawbacks. In this brief note I present a simple method that combines the advantages of spectral and spatial filtering, while minimizing their downsides. This method is applicable to multichannel data such as electroencephalography (EEG), magnetoencephalography (MEG), or multichannel local field potentials (LFP). I briefly review past methods, pointing out their drawbacks, describe the new method, and evaluate the outcome using synthetic and real data.

scholarly journals Electrophysiological Indices of Target and Distractor Processing in Visual Search

2009 ◽  
Vol 21 (4) ◽  
pp. 760-775 ◽  
Author(s):  
Clayton Hickey ◽  
Vincent Di Lollo ◽  
John J. McDonald
Keyword(s):  
Visual Search ◽  
Event Related Potential ◽  
Theoretical Interpretation ◽  
Cortical Representation ◽  
Distractor Processing ◽  
Electrophysiological Studies ◽  
Human Electrophysiology ◽  
Direct Suppression ◽  
Selection Of ◽  
Fundamental Mechanism

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.

scholarly journals The effects of spatial filtering and contrast reduction on visual search times in good and poor readers

1995 ◽  
Vol 35 (2) ◽  
pp. 285-291 ◽  
Author(s):  
Mary C. Williams ◽  
James G. May ◽  
Robert Solman ◽  
Hong Zhou
Keyword(s):  
Visual Search ◽  
Spatial Filtering ◽  
Poor Readers ◽  
Good And Poor Readers ◽  
Contrast Reduction

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

2013 ◽  
Vol 50 (7) ◽  
pp. 671-679 ◽  
Author(s):  
Ulysse Fortier-Gauthier ◽  
Roberto Dell'Acqua ◽  
Pierre Jolicœur
Keyword(s):  
Visual Search ◽  
Human Electrophysiology

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

2009 ◽  
Vol 21 (4) ◽  
pp. 725-733 ◽  
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.

The Influences of Goal and Laterality of a Prepared Hand Response on a Co-Occurring Visual Search

2015 ◽  
Vol 74 (1) ◽  
pp. 55-60 ◽  
Author(s):  
Alexandre Coutté ◽  
Gérard Olivier ◽  
Sylvane Faure
Keyword(s):  
Visual Search ◽  
Visual Target ◽  
Motor Planning ◽  
Search Performance ◽  
Response Preparation ◽  
Manual Response ◽  
Response Hand ◽  
Computer Screen ◽  
Left Hand ◽  
Manual Interaction

Computer use generally requires manual interaction with human-computer interfaces. In this experiment, we studied the influence of manual response preparation on co-occurring shifts of attention to information on a computer screen. The participants were to carry out a visual search task on a computer screen while simultaneously preparing to reach for either a proximal or distal switch on a horizontal device, with either their right or left hand. The response properties were not predictive of the target’s spatial position. The results mainly showed that the preparation of a manual response influenced visual search: (1) The visual target whose location was congruent with the goal of the prepared response was found faster; (2) the visual target whose location was congruent with the laterality of the response hand was found faster; (3) these effects have a cumulative influence on visual search performance; (4) the magnitude of the influence of the response goal on visual search is marginally negatively correlated with the rapidity of response execution. These results are discussed in the general framework of structural coupling between perception and motor planning.

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