a-Band (8‐14 Hz) oscillatory EEG activity was examined with high-density scalp electrical recording during the cue‐stimulus interval of an endogenous spatial cueing paradigm. In different blocks, cued spatial locations (left or right) were in either the upper or lower visual field, and attended stimuli were either oriented Ts or moving dots. Distractor stimuli were equally likely in the uncued hemifield. Sustained focal increases of a-band activity were seen over occipital cortex contralateral to the direction of the to-be-ignored location (ipsilateral to the cued direction of attention) before onset of the to-be-attended stimulus. The focus of a-band activity also moved depending on whether cued locations were in the upper or lower field. Results are consistent with active gating of uncued spatial locations.

https://www.jneurosci.org/content/jneuro/20/6/RC63.full.pdf

Anticipatory biasing of visuospatial attention indexed by retinotopically specific alpha-band electroencephalography increases over occipital cortex.

Top–down and bottom–up control of visual selection

Attention is a core property of all perceptual and cognitive operations. Given limited capacity to process competing options, attentional mechanisms select, modulate, and sustain focus on information most relevant for behavior. A significant problem, however, is that attention is so ubiquitous that it is unwieldy to study. We propose a taxonomy based on the types of information that attention operates over—the targets of attention. At the broadest level, the taxonomy distinguishes between external attention and internal attention. External attention refers to the selection and modulation of sensory information. External attention selects locations in space, points in time, or modality-specific input. Such perceptual attention can also select features defined across any of these dimensions, or object representations that integrate over space, time, and modality. Internal attention refers to the selection, modulation, and maintenance of internally generated information, such as task rules, responses, long-term memory, or working memory. Working memory, in particular, lies closest to the intersection between external and internal attention. The taxonomy provides an organizing framework that recasts classic debates, raises new issues, and frames understanding of neural mechanisms.

/pdf/a-taxonomy-of-external-and-internal-attention-3k4coy8dz1.pdf

A taxonomy of external and internal attention.

https://www.cell.com/trends/cognitive-sciences/pdf/S1364-6613(09)00046-1.pdf

How do emotion and motivation direct executive control

When an observer detects a target in a rapid stream of visual stimuli, there is a brief period of time during which the detection of subsequent targets is impaired. In this study, event-related potentials (ERPs) were recorded from normal adult observers to determine whether this "attentional blink" reflects a suppression of perceptual processes or an impairment in postperceptual processes. No suppression was observed during the attentional blink interval for ERP components corresponding to sensory processing (the P1 and N1 components) or semantic analysis (the N400 component). However, complete suppression was observed for an ERP component that has been hypothesized to reflect the updating of working memory (the P3 component). Results indicate that the attentional blink reflects an impairment in a postperceptual stage of processing.

Electrophysiological Evidence for a Postperceptual Locus of Suppression During the Attentional Blink

Many theories have proposed that visual working memory plays an important role in visual search. In contrast, by showing that a nonspatial working memory load did not interfere with search efficiency, Woodman, Vogel, and Luck (2001) recently proposed that the role of working memory in visual search is insignificant. However, the visual search process may interfere with spatial working memory. In the present study, a visual search task was performed concurrently with either a spatial working memory task (Experiment 1) or a nonspatial working memory task (Experiment 2). We found that the visual search process interfered with a spatial working memory load, but not with a nonspatial working memory load. These results suggest that there is a distinction between spatial and nonspatial working memory in terms of interactions with visual search tasks. These results imply that the visual search process and spatial working memory storage require the same limited-capacity mechanisms.

/pdf/the-role-of-spatial-working-memory-in-visual-search-3txfrg9db3.pdf

The role of spatial working memory in visual search efficiency

In two experiments using spatial probes, we measured the temporal and spatial interactions between top-down control of attention and bottom-up interference from a salient distractor in visual search. The subjects searched for a square among circles, ignoring color. Probe response times showed that a color singleton distractor could draw attention to its location in the early stage of visual processing (before a 100-msec stimulus onset asynchrony [SOA]), but only when the color singleton distractor was located far from the target. Apparently the bottom-up activation of the singleton distractor's location is affected early on by local interactions with nearby stimulus locations. Moreover, probe results showed that a singleton distractor did not receive attention after extended practice. These results suggest that top-down control of attention is possible at an early stage of visual processing. In the long-SOA condition (150-msec SOA), spatial attention selected the target location over distractor locations, and this tendency occurred with or without extended practice.

/pdf/top-down-and-bottom-up-attentional-control-on-the-nature-of-4x17koolwx.pdf

Top-down and bottom-up attentional control : On the nature of interference from a salient distractor

People have difficulty performing two tasks at once. For example, maintaining items in working memory (WM) makes people more distractible. However, different types of WM load may have different effects on attentional selection depending on whether WM load overlaps with mechanisms involved in target or distractor processing. Three experiments examined the effect of concurrent WM load on Stroop tasks, a widely used measure of executive control and inhibition. Stroop interference increased when the type of WM load overlapped with the type of information required for the target task (experiment 1). In striking contrast, Stroop interference decreased when the type of WM load overlapped with distractor processing (experiment 2). Experiment 3 replicated these results in a different Stroop task. Thus, concurrent WM load does not always impair executive control; performance depends on how contents of WM and task-relevant information overlap. The results highlight how dissociable components of WM interact with perception and executive control.

https://www.pnas.org/content/pnas/102/45/16524.full.pdf

Concurrent working memory load can reduce distraction.

Spatial attention was measured in visual search tasks using a spatial probe Both speed and accuracy measures showed that in a conjunction task, spatial attention was allocated to locations according to the presence of target features Also, contrary to some predictions, spatial attention was used when a clearly distinguishable feature defined the target The results raise questions about any account that assumes separate mechanisms for feature and conjunction search The probe method demonstrated here allows a very direct measurement of attentional allocation, and may uncover aspects of selection not revealed by visual search

Spatial Attention in Visual Search for Features and Feature Conjunctions

The allocation of spatial attention was measured with detection probes at different locations. Response times were faster for probes at the location of the target digit, which subjects reported, than at the locations of distractor digits, which they ignored. Probes at blank locations between stimuli produced fast responses, indicating that selection was accomplished by inhibiting distractor locations but not other areas. Unlike earlier studies using location cuing with simpler stimuli, these experiments showed no attentional differences across horizontal or vertical midlines. Attention varied little with distance from the target, although blank locations far from the target were somewhat less attended than were those near the target, and attention was only slightly affected by expectations for stimulus location. This task demonstrates a form of feature-driven spatial attention, in which locations with objects lacking target features are inhibited.

/pdf/spatial-selection-via-feature-driven-inhibition-of-46vblopx80.pdf

Min-Shik Kim

Papers

The role of spatial working memory in visual search efficiency

Top-down and bottom-up attentional control : On the nature of interference from a salient distractor

Concurrent working memory load can reduce distraction.

Spatial Attention in Visual Search for Features and Feature Conjunctions

Spatial selection via feature-driven inhibition of distractor locations.