scholarly journals In pursuit of visual attention: SSVEP frequency-tagging moving targets

2019 ◽  
Author(s):  
Peter de Lissa ◽  
Roberto Caldara ◽  
Victoria Nicholls ◽  
Sebastien Miellet
Keyword(s):  
Visual Attention ◽  
Visual Processing ◽  
Perceptual Load ◽  
Peripheral Region ◽  
Covert Attention ◽  
Neural Responses ◽  
Moving Targets ◽  
Overt Attention ◽  
Eeg Recordings ◽  
Practical Implications

AbstractPrevious research has shown that visual attention does not always exactly follow gaze direction, leading to the concepts of overt and covert attention. However, it is not yet clear how such covert shifts of visual attention to peripheral regions impact the processing of the targets we directly foveate as they move in our visual field. The current study utilised the co-registration of eye-position and EEG recordings while participants tracked moving targets that were embedded with a 30 Hz frequency tag in a Steady State Visually Evoked Potentials (SSVEP) paradigm. When the task required attention to be divided between the moving target (overt attention) and a peripheral region where a second target might appear (covert attention), the SSVEPs elicited by the tracked target at the 30 Hz frequency band were significantly lower than when participants did not have to covertly monitor for a second target. Our findings suggest that neural responses of overt attention are reduced when attention is divided between covert and overt areas. This neural evidence is in line with theoretical accounts describing attention as a pool of finite resources, such as the perceptual load theory. Altogether, these results have practical implications for many real-world situations where covert shifts of attention may reduce visual processing of objects even when they are directly being tracked with the eyes.

scholarly journals Attention in natural scenes: contrast affects rapid visual processing and fixations alike

2013 ◽  
Vol 368 (1628) ◽  
pp. 20130067 ◽  
Author(s):  
Bernard Marius 't Hart ◽  
Hannah Claudia Elfriede Fanny Schmidt ◽  
Ingo Klein-Harmeyer ◽  
Wolfgang Einhäuser
Keyword(s):  
Visual Processing ◽  
The Other ◽  
Covert Attention ◽  
Natural Scenes ◽  
Fixation Probability ◽  
Overt Attention ◽  
Rapid Visual Processing ◽  
Background Contrast ◽  
Different Time Scales ◽  
Rapid Presentation

For natural scenes, attention is frequently quantified either by performance during rapid presentation or by gaze allocation during prolonged viewing. Both paradigms operate on different time scales, and tap into covert and overt attention, respectively. To compare these, we ask some observers to detect targets (animals/vehicles) in rapid sequences, and others to freely view the same target images for 3 s, while their gaze is tracked. In some stimuli, the target's contrast is modified (increased/decreased) and its background modified either in the same or in the opposite way. We find that increasing target contrast relative to the background increases fixations and detection alike, whereas decreasing target contrast and simultaneously increasing background contrast has little effect. Contrast increase for the whole image (target + background) improves detection, decrease worsens detection, whereas fixation probability remains unaffected by whole-image modifications. Object-unrelated local increase or decrease of contrast attracts gaze, but less than actual objects, supporting a precedence of objects over low-level features. Detection and fixation probability are correlated: the more likely a target is detected in one paradigm, the more likely it is fixated in the other. Hence, the link between overt and covert attention, which has been established in simple stimuli, transfers to more naturalistic scenarios.

scholarly journals Covert spatial attention speeds target individuation

2019 ◽  
Author(s):  
Joshua J. Foster ◽  
Emma M. Bsales ◽  
Edward Awh
Keyword(s):  
Spatial Attention ◽  
Visual Processing ◽  
Object Representation ◽  
Target Location ◽  
Response Selection ◽  
Early Stage ◽  
Covert Attention ◽  
Object Representations ◽  
Neural Responses ◽  
Object Individuation

AbstractCovert spatial attention has long been thought to speed visual processing. Psychophysics studies have shown that target information accrues faster at attended locations than at unattended locations. However, with behavioral evidence alone, it is difficult to determine whether attention speeds visual processing of the target, or subsequent post-perceptual stages of processing (e.g. decision making and response selection). Moreover, while many studies have shown that that attention can boost the amplitude of visually-evoked neural responses, no effect has been observed on the latency of those neural responses. Here, we offer new evidence that may reconcile the neural and behavioral findings. Our study focused on the N2pc, an EEG marker of visual selection that has been linked with object individuation – the formation of an object representation that is distinct from the background and from other objects. In two experiments, we manipulated whether or not covert attention was precisely deployed to the location of an impending search target. We found that the target-evoked N2pc onset approximately 20 ms earlier when the target location was cued than when it was not cued. Thus, although attention may not speed the earliest stages of sensory processing, attention does speed the critical transition between raw sensory encoding and the formation of individuated object representations.Significance StatementCovert spatial attention improves processing at attended locations. Past behavioral studies have shown that information about visual targets accrues faster at attended than at unattended locations. However, it has remained unclear whether attention speeds perceptual analysis or subsequent post-perceptual stages of processing. Here we present robust evidence that attention speeds the N2pc, an electrophysiological signal that indexes the formation of individuated object representations. Our findings show that attention speeds a relatively early stage of perceptual processing, while also elucidating the specific perceptual process that is speeded.

scholarly journals Visual Attention and Aging: an Age-Related Cognitive Model of Positive Adaptation

2014 ◽  
Vol 4 (3) ◽  
pp. 181-191
Author(s):  
José Manuel Rodríguez-Ferrer
Keyword(s):  
Young People ◽  
Visual Attention ◽  
Response Times ◽  
Age Groups ◽  
Cognitive Model ◽  
Covert Attention ◽  
Positive Adaptation ◽  
Healthy Elderly ◽  
Age Related ◽  
Healthy Young People

We have studied the effects of normal aging on visual attention. Have participated a group of 38 healthy elderly people with an average age of 67.8 years and a group of 39 healthy young people with average age of 19.2 years. In a first experiment of visual detection, response times were recorded, with and without covert attention, to the presentation of stimuli (0.5º in diameter grey circles) appearing in three eccentricities (2.15, 3.83 and 5.53° of visual field) and with three levels of contrast (6, 16 and 78%). In a second experiment of visual form discrimination circles and squares with the same features as in the previous experiment were presented, but in this case subjects only should respond to the emergence of the circles. In both age groups, the covert attention reduced response times. Compared to young people, the older group achieved better results in some aspects of attention tests and response times were reduced more in the stimuli of greater eccentricity. The data suggest that there is a mechanism of adaptation in aging, in which visual attention especially favors the perception of those stimuli more difficult to detec

scholarly journals Sustained Splits of Attention within versus across Visual Hemifields Produce Distinct Spatial Gain Profiles

2016 ◽  
Vol 28 (1) ◽  
pp. 111-124 ◽  
Author(s):  
Sabrina Walter ◽  
Christian Keitel ◽  
Matthias M. Müller
Keyword(s):  
Visual Attention ◽  
Visual Processing ◽  
Behavioral Performance ◽  
Lower Visual Field ◽  
Light Emitting ◽  
Visual Hemifield ◽  
Attention Tasks ◽  
Visual Cortices ◽  
Cortical Visual Processing ◽  
Visual Hemifields

Visual attention can be focused concurrently on two stimuli at noncontiguous locations while intermediate stimuli remain ignored. Nevertheless, behavioral performance in multifocal attention tasks falters when attended stimuli fall within one visual hemifield as opposed to when they are distributed across left and right hemifields. This “different-hemifield advantage” has been ascribed to largely independent processing capacities of each cerebral hemisphere in early visual cortices. Here, we investigated how this advantage influences the sustained division of spatial attention. We presented six isoeccentric light-emitting diodes (LEDs) in the lower visual field, each flickering at a different frequency. Participants attended to two LEDs that were spatially separated by an intermediate LED and responded to synchronous events at to-be-attended LEDs. Task-relevant pairs of LEDs were either located in the same hemifield (“within-hemifield” conditions) or separated by the vertical meridian (“across-hemifield” conditions). Flicker-driven brain oscillations, steady-state visual evoked potentials (SSVEPs), indexed the allocation of attention to individual LEDs. Both behavioral performance and SSVEPs indicated enhanced processing of attended LED pairs during “across-hemifield” relative to “within-hemifield” conditions. Moreover, SSVEPs demonstrated effective filtering of intermediate stimuli in “across-hemifield” condition only. Thus, despite identical physical distances between LEDs of attended pairs, the spatial profiles of gain effects differed profoundly between “across-hemifield” and “within-hemifield” conditions. These findings corroborate that early cortical visual processing stages rely on hemisphere-specific processing capacities and highlight their limiting role in the concurrent allocation of visual attention to multiple locations.

Visual attention in adults with attention-deficit/hyperactivity disorder before and after stimulant treatment

2018 ◽  
Vol 49 (15) ◽  
pp. 2617-2625 ◽  
Author(s):  
Ann-Marie Low ◽  
Signe Vangkilde ◽  
Julijana le Sommer ◽  
Birgitte Fagerlund ◽  
Birte Glenthøj ◽  
...  
Keyword(s):  
Attention Deficit Hyperactivity Disorder ◽  
Visual Attention ◽  
Attention Deficit ◽  
Processing Speed ◽  
Visual Processing ◽  
Stimulant Medication ◽  
Hyperactivity Disorder ◽  
Visual Processing Speed ◽  
Adhd Symptomatology

AbstractBackgroundAttention-deficit/hyperactivity disorder (ADHD) is a neurodevelopmental disorder which frequently persists into adulthood. The primary goal of the current study was to (a) investigate attentional functions of stimulant medication-naïve adults with ADHD, and (b) investigate the effects of 6 weeks of methylphenidate treatment on these functions.MethodsThe study was a prospective, non-randomized, non-blinded, 6-week follow-up design with 42 stimulant medication-naïve adult patients with ADHD, and 42 age and parental education-matched healthy controls. Assessments included measures of visual attention, based on Bundesen's Theory of Visual Attention (TVA), which yields five precise measures of aspects of visual attention; general psychopathology; ADHD symptoms; dyslexia screening; and estimates of IQ.ResultsAt baseline, significant differences were found between patients and controls on three attentional parameters: visual short-term memory capacity, threshold of conscious perception, and to a lesser extent visual processing speed. Secondary analyses revealed no significant correlations between TVA parameter estimates and severity of ADHD symptomatology. At follow-up, significant improvements were found specifically for visual processing speed; this improvement had a large effect size, and remained when controlling for re-test effects, IQ, and dyslexia screen performance. There were no significant correlations between changes in visual processing speed and changes in ADHD symptomatology.ConclusionsADHD in adults may be associated with deficits in three distinct aspects of visual attention. Improvements after 6 weeks of medication are seen specifically in visual processing speed, which could represent an improvement in alertness. Clinical symptoms and visual attentional deficits may represent separate aspects of ADHD in adults.

scholarly journals Driving and visual deficits in stroke patients

2018 ◽  
Vol 76 (2) ◽  
pp. 85-88 ◽  
Author(s):  
Marina Marcondes Braga ◽  
Renato Nickel ◽  
Marcos Lange ◽  
Élcio Juliato Piovesan
Keyword(s):  
High Risk ◽  
Visual Attention ◽  
Visual Processing ◽  
Moderate Risk ◽  
Interference Factor ◽  
Visual Deficits ◽  
Useful Field Of View ◽  
High Level ◽  
Safe Performance ◽  
Intention Group

ABSTRACT Objective: The aim of the present study was to conduct an exploratory assessment of visual impairment following stroke, and to discuss the possibilities of reintroducing patients to the activity of driving. Methods: The Useful Field of View test was used to assess visual processing and visual attention. Results: A total of 18 patients were included in the study, and were assigned to either the drive group (n = 9) or the intention group (n = 9). In the drive group, one patient was categorized as moderate-to-high risk; whereas, in the intention group, one patient was categorized as low-to-moderate risk. Additionally, two patients in the intention group were categorized as high risk. The patients did not perceive their visual deficits as a limitation. Conclusion: Visual attention is an interference factor in terms of the safe performance of driving after a stroke. All patients showed a high level of interest for the independence provided through being able to drive.

scholarly journals LIP activity in the interstimulus interval of a change detection task biases the behavioral response

2015 ◽  
Vol 114 (5) ◽  
pp. 2637-2648 ◽  
Author(s):  
Fabrice Arcizet ◽  
Koorosh Mirpour ◽  
Daniel J. Foster ◽  
Caroline J. Charpentier ◽  
James W. Bisley
Keyword(s):  
Eye Movements ◽  
Change Detection ◽  
Behavioral Response ◽  
Interstimulus Interval ◽  
Detection Task ◽  
Covert Attention ◽  
Change Detection Task ◽  
Lateral Intraparietal Area ◽  
Overt Attention ◽  
The World

When looking around at the world, we can only attend to a limited number of locations. The lateral intraparietal area (LIP) is thought to play a role in guiding both covert attention and eye movements. In this study, we tested the involvement of LIP in both mechanisms with a change detection task. In the task, animals had to indicate whether an element changed during a blank in the trial by making a saccade to it. If no element changed, they had to maintain fixation. We examine how the animal's behavior is biased based on LIP activity prior to the presentation of the stimulus the animal must respond to. When the activity was high, the animal was more likely to make an eye movement toward the stimulus, even if there was no change; when the activity was low, the animal either had a slower reaction time or maintained fixation, even if a change occurred. We conclude that LIP activity is involved in both covert and overt attention, but when decisions about eye movements are to be made, this role takes precedence over guiding covert attention.

P367 Identification of neural responses to human faces using wireless multichannel EEG recordings

2017 ◽  
Vol 128 (9) ◽  
pp. e297
Author(s):  
Vicente Soto ◽  
John Tyson-Carr ◽  
Katerina Kokmotou ◽  
Hannah Roberts ◽  
Stephanie Cook ◽  
...  
Keyword(s):  
Neural Responses ◽  
Eeg Recordings ◽  
Human Faces ◽  
Multichannel Eeg

scholarly journals Decreased Visual Attention Further from the Perceived Direction of Gaze for Equidistant Retinal Targets

2011 ◽  
Vol 23 (3) ◽  
pp. 661-669 ◽  
Author(s):  
Daniela Balslev ◽  
Emma Gowen ◽  
R. Chris Miall
Keyword(s):  
Visual Attention ◽  
Visual Processing ◽  
Repetitive Transcranial Magnetic Stimulation ◽  
Eye Position ◽  
Eye Muscle ◽  
Visual Hemifield ◽  
Proprioceptive Signal ◽  
Visual Targets ◽  
Attention Systems ◽  
The Right

The oculomotor and spatial attention systems are interconnected. Whereas a link between motor commands and spatial shifts in visual attention is demonstrated, it is still unknown whether the recently discovered proprioceptive signal in somatosensory cortex impacts on visual attention, too. This study investigated whether visual targets near the perceived direction of gaze are detected more accurately than targets further away, despite the equal eccentricity of their retinal projections. We dissociated real and perceived eye position using left somatosensory repetitive transcranial magnetic stimulation (rTMS), which decreases cortical processing of eye muscle proprioceptive inflow and produces an underestimation of the rotation of the right eye. Participants detected near-threshold visual targets presented in the left or right visual hemifield at equal distance from fixation. We have previously shown that when the right eye is rotated to the left of the parasagittal plane, TMS produces an underestimation of this rotation, shifting perceived eye position to the right. Here we found that, in this condition, TMS also decreased target detection in the left visual hemifield and increased it in the right. This effect depended on the direction of rotation of the right eye. When the right eye was rotated rightward and TMS, we assume, shifted perceived gaze direction in opposite direction, leftward, visual accuracy decreased now in the right hemifield. We suggest that the proprioceptive eye position signal modulates the spatial distribution of visual processing resources, producing “pseudo-neglect” for objects located far relative to near the perceived direction of gaze.

scholarly journals Neural Responses to Ambiguity Involve Domain-general and Domain-specific Emotion Processing Systems

2013 ◽  
Vol 25 (4) ◽  
pp. 547-557 ◽  
Author(s):  
Maital Neta ◽  
William M. Kelley ◽  
Paul J. Whalen
Keyword(s):  
Decision Making ◽  
Facial Expressions ◽  
Visual Processing ◽  
Neural Responses ◽  
Social Signals ◽  
Emotional Facial Expressions ◽  
Biologically Relevant ◽  
Domain Specific ◽  
Specific Emotion ◽  
On Line

Extant research has examined the process of decision making under uncertainty, specifically in situations of ambiguity. However, much of this work has been conducted in the context of semantic and low-level visual processing. An open question is whether ambiguity in social signals (e.g., emotional facial expressions) is processed similarly or whether a unique set of processors come on-line to resolve ambiguity in a social context. Our work has examined ambiguity using surprised facial expressions, as they have predicted both positive and negative outcomes in the past. Specifically, whereas some people tended to interpret surprise as negatively valenced, others tended toward a more positive interpretation. Here, we examined neural responses to social ambiguity using faces (surprise) and nonface emotional scenes (International Affective Picture System). Moreover, we examined whether these effects are specific to ambiguity resolution (i.e., judgments about the ambiguity) or whether similar effects would be demonstrated for incidental judgments (e.g., nonvalence judgments about ambiguously valenced stimuli). We found that a distinct task control (i.e., cingulo-opercular) network was more active when resolving ambiguity. We also found that activity in the ventral amygdala was greater to faces and scenes that were rated explicitly along the dimension of valence, consistent with findings that the ventral amygdala tracks valence. Taken together, there is a complex neural architecture that supports decision making in the presence of ambiguity: (a) a core set of cortical structures engaged for explicit ambiguity processing across stimulus boundaries and (b) other dedicated circuits for biologically relevant learning situations involving faces.

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