Neural Processes Involved in Directing Attention

1989 ◽  
Vol 1 (3) ◽  
pp. 223-237 ◽  
Author(s):  
M. Russell Harter ◽  
Steven L. Miller ◽  
Natalie J. Price ◽  
Margaret E. LaLonde ◽  
Alvin L. Keyes
Keyword(s):  
Visual Field ◽  
Spatial Attention ◽  
Cortical Excitability ◽  
Visual Fields ◽  
Event Related Potential ◽  
Right Visual Field ◽  
Hemispheric Differences ◽  
Visual Spatial ◽  
Neural Processes ◽  
Directing Attention

Neural processes associated with two aspects of visual-spatial attention were investigated with event-related potential (ERPs): those that direct spatial attention to a given point in space and those that modulate the processing of sensory input after attention has been directed. The subjects were 6- to 9-year-old children (51 boys and 35 girls). An arrow cue directed attention from the central to peripheral visual field; targets were then flashed in the attended or ignored visual field 600 msec after the cue. The directing of attention to the left vs. right visual field was associated with hemispheric differences in slow potentials prior to the presentation of the targets. The earliest potential, which started about 200 msec after the cue and was negative over the hemisphere contralateral to the direction of attention, was greatest over the parietal area and appeared to reflect processes directing attention per se. The last potential, which peaked 60 msec after the target and was positive over the hemisphere contralateral to the direction of attention, was greatest over the occipital-parietal region. It appeared to reflect the modulation of cortical excitability in the regions receiving input from the relevant and irrelevant visual fields. The effects of spatial attention on P1, N1, and P3 ERP components following the targets replicated previous results. Boys appeared more aroused (as indicated by CNVs) and reflected faster and greater selective processing (as indicated by reaction time, and N1-P1 latency and amplitude) than girls.

scholarly journals Functionally independent components of early event-related potentials in a visual spatial attention task

1999 ◽  
Vol 354 (1387) ◽  
pp. 1135-1144 ◽  
Author(s):  
Scott Makeig ◽  
Marissa Westerfield ◽  
Jeanne Townsend ◽  
Tzyy-Ping Jung ◽  
Eric Courchesne ◽  
...  
Keyword(s):  
Visual Field ◽  
Spatial Attention ◽  
Visual Target ◽  
Event Related Potentials ◽  
Event Related Potential ◽  
Right Visual Field ◽  
Early Event ◽  
Attention Task ◽  
Visual Spatial ◽  
Related Potentials

Spatial visual attention modulates the first negative–going deflection in the human averaged event–related potential (ERP) in response to visual target and non–target stimuli (the N1 complex). Here we demonstrate a decomposition of N1 into functionally independent subcomponents with functionally distinct relations to task and stimulus conditions. ERPs were collected from 20 subjects in response to visual target and non–target stimuli presented at five attended and non–attended screen locations. Independent component analysis, a new method for blind source separation, was trained simultaneously on 500 ms grand average responses from all 25 stimulus–attention conditions and decomposed the non–target N1 complexes into five spatially fixed, temporally independent and physiologically plausible components. Activity of an early, laterally symmetrical component pair (N1a R and N1a L ) was evoked by the left and right visual field stimuli, respectively. Component N1a R peaked ca. 9 ms earlier than N1a L . Central stimuli evoked both components with the same peak latency difference, producing a bilateral scalp distribution. The amplitudes of these components were not reliably augmented by spatial attention. Stimuli in the right visual field evoked activity in a spatio–temporally overlapping bilateral component (N1b) that peaked at ca. 180 ms and was strongly enhanced by attention. Stimuli presented at unattended locations evoked a fourth component (P2a) peaking near 240 ms. A fifth component (P3f) was evoked only by targets presented in either visual field. The distinct response patterns of these components across the array of stimulus and attention conditions suggest that they reflect activity in functionally independent brain systems involved in processing attended and unattended visuospatial events.

On the Relation between Visual Spatial Attention and Visual Field Asymmetries

1992 ◽  
Vol 44 (3) ◽  
pp. 529-555 ◽  
Author(s):  
T. A Mondor ◽  
M.P. Bryden
Keyword(s):  
Visual Field ◽  
Visual Attention ◽  
Visual Fields ◽  
Stimulus Onset ◽  
Right Visual Field ◽  
Structural Factors ◽  
Letter Identification ◽  
Functional Capabilities ◽  
Visual Spatial ◽  
The Right

In the typical visual laterality experiment, words and letters are more rapidly and accurately identified in the right visual field than in the left. However, while such studies usually control fixation, the deployment of visual attention is rarely restricted. The present studies investigated the influence of visual attention on the visual field asymmetries normally observed in single-letter identification and lexical decision tasks. Attention was controlled using a peripheral cue that provided advance knowledge of the location of the forthcoming stimulus. The time period between the onset of the cue and the onset of the stimulus (Stimulus Onset Asynchrony—SOA) was varied, such that the time available for attention to focus upon the location was controlled. At short SO As a right visual field advantage for identifying single letters and for making lexical decisions was apparent. However, at longer SOAs letters and words presented in the two visual fields were identified equally well. It is concluded that visual field advantages arise from an interaction of attentional and structural factors and that the attentional component in visual field asymmetries must be controlled in order to approximate more closely a true assessment of the relative functional capabilities of the right and left cerebral hemispheres.

Right Hemisphere Memory Bias Does Not Extend to Involuntary Memories for Negative Scenes

Perception ◽  
2021 ◽  
Vol 50 (1) ◽  
pp. 27-38
Author(s):  
Ella K. Moeck ◽  
Nicole A. Thomas ◽  
Melanie K. T. Takarangi
Keyword(s):  
Visual Field ◽  
Left Hemisphere ◽  
Right Hemisphere ◽  
Visual Fields ◽  
Memory Bias ◽  
Right Visual Field ◽  
Hemispheric Differences ◽  
Involuntary Memory ◽  
Involuntary Memories ◽  
The Right

Attention is unequally distributed across the visual field. Due to greater right than left hemisphere activation for visuospatial attention, people attend slightly more to the left than the right side. As a result, people voluntarily remember visual stimuli better when it first appears in the left than the right visual field. But does this effect—termed a right hemisphere memory bias—also enhance involuntary memory? We manipulated the presentation location of 100 highly negative images (chosen to increase the likelihood that participants would experience any involuntary memories) in three conditions: predominantly leftward (right hemisphere bias), predominantly rightward (left hemisphere bias), or equally in both visual fields (bilateral). We measured subsequent involuntary memories immediately and for 3 days after encoding. Contrary to predictions, biased hemispheric processing did not affect short- or long-term involuntary memory frequency or duration. Future research should measure hemispheric differences at retrieval, rather than just encoding.

scholarly journals Exploration of the Hemispheric Differences in Number Processing of the Brain

2012 ◽  
Vol 1 (2) ◽  
pp. 55-61
Author(s):  
Aaron Wyland Walters
Keyword(s):  
Reaction Time ◽  
Visual Field ◽  
Right Hemisphere ◽  
Visual Fields ◽  
Reaction Time Data ◽  
Right Visual Field ◽  
Hemispheric Differences ◽  
Time Data ◽  
Central Target ◽  
The Right

Abstract The current study explored how reaction time and accuracy differed in the left and right visual fields by altering various dot clusters in both number and organization. Researchers have hypothesized that the left hemisphere uses counting to judge small, disorganized clusters of objects accurately and that the right hemisphere uses estimation to judge clusters organized in geometric shape accurately. The current study tested both visual fields of participant’s with organized and unorganized clusters of dots. Dots were clustered between 3 and 12. The clusters were presented on separate sides of a computer screen to analyze visual field differences in counting and estimation. A central target was presented on the screen to maintain central focus for the visual fields. Data from 40 participants (30 men, 10 women) from a small liberal arts college indicated that when clusters reached between 7 and 8 dots, organization in the right visual field created inaccuracy in judgment. Reaction time data indicated that as number level increased, reaction time slowed. Reaction time data also showed that organization slowed reaction times in both visual fields. These data indicated that different numerical judgment abilities do exist within the hemispheres.

Attention and Hemispheric Differences in Reaction Time during Simultaneous Audio-Visual Tasks

1973 ◽  
Vol 25 (3) ◽  
pp. 404-412 ◽  
Author(s):  
Gina Geffen ◽  
J. L. Bradshaw ◽  
N. C. Nettleton
Keyword(s):  
Reaction Time ◽  
Visual Field ◽  
Right Hemisphere ◽  
Visual Fields ◽  
Normal Subjects ◽  
Auditory Task ◽  
Right Visual Field ◽  
Hemispheric Differences ◽  
Language Functions ◽  
The Right

The effect of different types of competing auditory tasks on laterality differences in visual perception was investigated. Right-handed subjects were presented with digits which occurred randomly in the left or right visual fields. They responded vocally to previously specified digits in a go, no-go reaction time situation. In the absence of any competing auditory task, digits presented in the right visual field were processed more quickly. This visual field difference in reaction time was in the same direction while subjects performed a secondary musical task. However, when a secondary verbal task had to be performed, digits in the left visual field received faster responses. The results support the view that the right hemisphere is capable of some language functions, and that hemispheric differences in performance have at their basis a quantitative asymmetry, which can be reversed even in normal subjects by overloading their limited capacity.

scholarly journals Impact of Stimulus Features on the Performance of a Gaze-Independent Brain-Computer Interface Based on Covert Spatial Attention Shifts

2020 ◽  
Vol 14 ◽  
Author(s):  
Christoph Reichert ◽  
Igor Fabian Tellez Ceja ◽  
Catherine M. Sweeney-Reed ◽  
Hans-Jochen Heinze ◽  
Hermann Hinrichs ◽  
...  
Keyword(s):  
Visual Acuity ◽  
Eye Movements ◽  
Visual Field ◽  
Spatial Attention ◽  
Brain Computer Interface ◽  
Computer Interface ◽  
Right Visual Field ◽  
Oddball Paradigm ◽  
Visual Spatial ◽  
Stimulus Features

Regaining communication abilities in patients who are unable to speak or move is one of the main goals in decoding brain waves for brain-computer interface (BCI) control. Many BCI approaches designed for communication rely on attention to visual stimuli, commonly applying an oddball paradigm, and require both eye movements and adequate visual acuity. These abilities may, however, be absent in patients who depend on BCI communication. We have therefore developed a response-based communication BCI, which is independent of gaze shifts but utilizes covert shifts of attention to the left or right visual field. We recorded the electroencephalogram (EEG) from 29 channels and coregistered the vertical and horizontal electrooculogram. Data-driven decoding of small attention-based differences between the hemispheres, also known as N2pc, was performed using 14 posterior channels, which are expected to reflect correlates of visual spatial attention. Eighteen healthy participants responded to 120 statements by covertly directing attention to one of two colored symbols (green and red crosses for “yes” and “no,” respectively), presented in the user’s left and right visual field, respectively, while maintaining central gaze fixation. On average across participants, 88.5% (std: 7.8%) of responses were correctly decoded online. In order to investigate the potential influence of stimulus features on accuracy, we presented the symbols with different visual angles, by altering symbol size and eccentricity. The offline analysis revealed that stimulus features have a minimal impact on the controllability of the BCI. Hence, we show with our novel approach that spatial attention to a colored symbol is a robust method with which to control a BCI, which has the potential to support severely paralyzed people with impaired eye movements and low visual acuity in communicating with their environment.

Visual Spatial Attention in Migraine Sufferers in Postictal and Interictal Phases: An Event-Related Potential Study

2001 ◽  
Vol 15 (1) ◽  
pp. 22-34 ◽  
Author(s):  
D.H. de Koning ◽  
J.C. Woestenburg ◽  
M. Elton
Keyword(s):  
Cerebral Cortex ◽  
Visual Attention ◽  
Migraine Attack ◽  
Spatial Attention ◽  
Event Related Potential ◽  
Significant Enhancement ◽  
Pathophysiological Mechanism ◽  
Attention Task ◽  
Visual Spatial Attention ◽  
Visual Spatial

Migraineurs with and without aura (MWAs and MWOAs) as well as controls were measured twice with an interval of 7 days. The first session of recordings and tests for migraineurs was held about 7 hours after a migraine attack. We hypothesized that electrophysiological changes in the posterior cerebral cortex related to visual spatial attention are influenced by the level of arousal in migraineurs with aura, and that this varies over the course of time. ERPs related to the active visual attention task manifested significant differences between controls and both types of migraine sufferers for the N200, suggesting a common pathophysiological mechanism for migraineurs. Furthermore, migraineurs without aura (MWOAs) showed a significant enhancement for the N200 at the second session, indicating the relevance of time of measurement within migraine studies. Finally, migraineurs with aura (MWAs) showed significantly enhanced P240 and P300 components at central and parietal cortical sites compared to MWOAs and controls, which seemed to be maintained over both sessions and could be indicative of increased noradrenergic activity in MWAs.

Hemispheric Specialization for Processing Chinese Characters: Some Evidence from Lexical Decision Vocal Reaction Times

1989 ◽  
Vol 69 (3_suppl) ◽  
pp. 1083-1089 ◽  
Author(s):  
Michael P. Rastatter ◽  
Gail Scukanec ◽  
Jeff Grilliot
Keyword(s):  
Visual Field ◽  
Lexical Decision ◽  
Hemispheric Specialization ◽  
Visual Fields ◽  
Reaction Times ◽  
Decision Processes ◽  
Right Visual Field ◽  
Chinese Characters ◽  
Error Type ◽  
Chinese Subjects

Lexical decision vocal reaction times (RT) were obtained for a group of Chinese subjects to unilateral tachistoscopically presented pictorial, single, and combination Chinese characters. The RT showed a significant right visual-field advantage, with significant correlations of performance between the visual fields for each type of character. Error analysis gave a significant interaction between visual fields and error type—significantly more false positive errors occurred following left visual-field inputs. These results suggest that the left hemisphere was responsible for processing each type of character, possibly reflecting superior postaccess lexical-decision processes.

Occipitoparietal alpha-band responses to the graded allocation of top-down spatial attention

2014 ◽  
Vol 112 (6) ◽  
pp. 1307-1316 ◽  
Author(s):  
Isabel Dombrowe ◽  
Claus C. Hilgetag
Keyword(s):  
Visual Field ◽  
Spatial Attention ◽  
Brain Regions ◽  
Alpha Band ◽  
Top Down ◽  
Attentional Resources ◽  
Parietal Lobes ◽  
Visual Spatial ◽  
Entire Visual Field ◽  
Band Activity

The voluntary, top-down allocation of visual spatial attention has been linked to changes in the alpha-band of the electroencephalogram (EEG) signal measured over occipital and parietal lobes. In the present study, we investigated how occipitoparietal alpha-band activity changes when people allocate their attentional resources in a graded fashion across the visual field. We asked participants to either completely shift their attention into one hemifield, to balance their attention equally across the entire visual field, or to attribute more attention to one-half of the visual field than to the other. As expected, we found that alpha-band amplitudes decreased stronger contralaterally than ipsilaterally to the attended side when attention was shifted completely. Alpha-band amplitudes decreased bilaterally when attention was balanced equally across the visual field. However, when participants allocated more attentional resources to one-half of the visual field, this was not reflected in the alpha-band amplitudes, which just decreased bilaterally. We found that the performance of the participants was more strongly reflected in the coherence between frontal and occipitoparietal brain regions. We conclude that low alpha-band amplitudes seem to be necessary for stimulus detection. Furthermore, complete shifts of attention are directly reflected in the lateralization of alpha-band amplitudes. In the present study, a gradual allocation of visual attention across the visual field was only indirectly reflected in the alpha-band activity over occipital and parietal cortexes.

Interocular torsional disparity and visual cortical development in the cat

1990 ◽  
Vol 64 (4) ◽  
pp. 1352-1360 ◽  
Author(s):  
M. R. Isley ◽  
D. C. Rogers-Ramachandran ◽  
P. G. Shinkman
Keyword(s):  
Visual Cortex ◽  
Visual Field ◽  
Ocular Dominance ◽  
Visual Fields ◽  
Receptive Fields ◽  
Right Visual Field ◽  
Orientation Columns ◽  
Areas 17 And 18 ◽  
The Right ◽  
Visual Cortical

1. The present experiments were designed to assess the effects of relatively large optically induced interocular torsional disparities on the developing kitten visual cortex. Kittens were reared with restricted visual experience. Three groups viewed a normal visual environment through goggles fitted with small prisms that introduced torsional disparities between the left and right eyes' visual fields, equal but opposite in the two eyes. Kittens in the +32 degrees goggle rearing condition experienced a 16 degrees counterclockwise rotation of the left visual field and a 16 degrees clockwise rotation of the right visual field; in the -32 degrees goggle condition the rotations were clockwise in the left eye and counterclockwise in the right. In the control (0 degree) goggle condition, the prisms did not rotate the visual fields. Three additional groups viewed high-contrast square-wave gratings through Polaroid filters arranged to provide a constant 32 degrees of interocular orientation disparity. 2. Recordings were made from neurons in visual cortex around the border of areas 17 and 18 in all kittens. Development of cortical ocular dominance columns was severely disrupted in all the experimental (rotated) rearing conditions. Most cells were classified in the extreme ocular dominance categories 1, 2, 6, and 7. Development of the system of orientation columns was also affected: among the relatively few cells with oriented receptive fields in both eyes, the distributions of interocular disparities in preferred stimulus orientation were centered near 0 degree but showed significantly larger variances than in the control condition.(ABSTRACT TRUNCATED AT 250 WORDS)

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