Selective Attention to Spatial Frequency Gratings Affects Visual Processing as Early as 60 MSEC. Poststimulus

2009 ◽  
Vol 109 (1) ◽  
pp. 140-158 ◽  
Author(s):  
Alberto Zani ◽  
Alice Mado Proverbio
Keyword(s):  
Selective Attention ◽  
Spatial Frequency ◽  
Visual Processing ◽  
Striate Cortex ◽  
Event Related Potentials ◽  
Mean Amplitude ◽  
Related Potentials ◽  
Sensory Activity ◽  
Sensory Evoked ◽  
Selection Mechanisms

Event-related potentials (ERPs) were recorded from occipital sites to investigate early selection mechanisms and to determine the time at which attention modifies the processing activity of the visual cortex in humans. 19 right-handed participants served as paid volunteers. The task consisted in paying selective attention to a combination of spatial frequency and location and then responding to target stimuli while ignoring other combinations of features. Sensory-evoked components were analyzed by measuring mean amplitude values within the latency ranges of 60–80, 80–100, 100–120, and 120–140 msec, poststimulus. Stimuli relevant in frequency and/or location elicited larger evoked CI responses than unattended stimuli as early as 60–80 msec, poststimulus, a range that likely corresponds to sensory activity in the striate cortex, although due to the small number of recording sites, the activity could not be precisely localized.

scholarly journals Anorexia nervosa and body dysmorphic disorder are associated with abnormalities in processing visual information

2015 ◽  
Vol 45 (10) ◽  
pp. 2111-2122 ◽  
Author(s):  
W. Li ◽  
T. M. Lai ◽  
C. Bohon ◽  
S. K. Loo ◽  
D. McCurdy ◽  
...  
Keyword(s):  
Anorexia Nervosa ◽  
Spatial Frequency ◽  
Visual Processing ◽  
Visual Information ◽  
Body Dysmorphic Disorder ◽  
High Spatial Frequency ◽  
Event Related Potentials ◽  
Visual Stream ◽  
N170 Component ◽  
Related Potentials

BackgroundAnorexia nervosa (AN) and body dysmorphic disorder (BDD) are characterized by distorted body image and are frequently co-morbid with each other, although their relationship remains little studied. While there is evidence of abnormalities in visual and visuospatial processing in both disorders, no study has directly compared the two. We used two complementary modalities – event-related potentials (ERPs) and functional magnetic resonance imaging (fMRI) – to test for abnormal activity associated with early visual signaling.MethodWe acquired fMRI and ERP data in separate sessions from 15 unmedicated individuals in each of three groups (weight-restored AN, BDD, and healthy controls) while they viewed images of faces and houses of different spatial frequencies. We used joint independent component analyses to compare activity in visual systems.ResultsAN and BDD groups demonstrated similar hypoactivity in early secondary visual processing regions and the dorsal visual stream when viewing low spatial frequency faces, linked to the N170 component, as well as in early secondary visual processing regions when viewing low spatial frequency houses, linked to the P100 component. Additionally, the BDD group exhibited hyperactivity in fusiform cortex when viewing high spatial frequency houses, linked to the N170 component. Greater activity in this component was associated with lower attractiveness ratings of faces.ConclusionsResults provide preliminary evidence of similar abnormal spatiotemporal activation in AN and BDD for configural/holistic information for appearance- and non-appearance-related stimuli. This suggests a common phenotype of abnormal early visual system functioning, which may contribute to perceptual distortions.

The Role of Spatial Selective Attention in Working Memory for Locations: Evidence from Event-Related Potentials

2000 ◽  
Vol 12 (5) ◽  
pp. 840-847 ◽  
Author(s):  
Edward Awh ◽  
Lourdes Anllo-Vento ◽  
Steven A. Hillyard
Keyword(s):  
Working Memory ◽  
Selective Attention ◽  
Visual Processing ◽  
Spatial Working Memory ◽  
Memory Task ◽  
Stimulus Display ◽  
Event Related Potentials ◽  
Related Potentials ◽  
On Line ◽  
Multichannel Recordings

We investigated the hypothesis that the covert focusing of spatial attention mediates the on-line maintenance of location information in spatial working memory. During the delay period of a spatial working-memory task, behaviorally irrelevant probe stimuli were flashed at both memorized and nonmemorized locations. Multichannel recordings of event-related potentials (ERPs) were used to assess visual processing of the probes at the different locations. Consistent with the hypothesis of attention-based rehearsal, early ERP components were enlarged in response to probes that appeared at memorized locations. These visual modulations were similar in latency and topography to those observed after explicit manipulations of spatial selective attention in a parallel experimental condition that employed an identical stimulus display.

Attention and Sensory Gain Control: A Peripheral Visual Process?

2005 ◽  
Vol 17 (12) ◽  
pp. 1936-1949 ◽  
Author(s):  
Todd C. Handy ◽  
Wayne Khoe
Keyword(s):  
Striate Cortex ◽  
Target Location ◽  
Reaction Times ◽  
Gain Control ◽  
Event Related Potentials ◽  
Stimulus Contrast ◽  
Attention Task ◽  
Related Potentials ◽  
Sensory Evoked ◽  
Target Locations

Attention-related sensory gain control in human extra-striate cortex is believed to improve the acuity of visual perception. Yet given wide variance in the spatial resolution of vision across the retina, it remains unclear whether sensory gain operates homogenously between foveal and nonfoveal retinotopic locations. To address this issue, we used event-related potentials (ERPs) in a variant of the canonical spatial attention task. Participants were cued to expect targets at either fixation (foveal targets) or at a location several degrees above fixation (parafoveal targets). At both target locations, manual reaction times were shorter for cued relative to uncued targets, indicating that attention was consistently oriented to the cued location. Nevertheless, attention-related increases in sensory-evoked cortical activity were only observed at the parafoveal target location, as measured by the amplitude of the lateral occipital P1 ERP component. A second experiment replicated this data pattern using targets with lower stimulus contrast, indicating that the absence of a P1 effect for foveal targets could not be attributed to a saturated P1 response under higher-contrast stimulus conditions. When considered in light of retinogeniculate projections to cortex showing systematic changes in their physiological organization beginning within a degree of visual angle of the fovea, our findings support the proposal that the strategic functions of visual attention may vary with the retinotopic location involved.

scholarly journals Repetitive transcanial magnetic stimulation (RTMS) modulates event-related potential (ERP) indices of attention in autism

2012 ◽  
Vol 3 (2) ◽  
Author(s):  
Manuel Casanova ◽  
Joshua Baruth ◽  
Ayman El-Baz ◽  
Allan Tasman ◽  
Lonnie Sears ◽  
...  
Keyword(s):  
Selective Attention ◽  
Visual Processing ◽  
Magnetic Stimulation ◽  
Repetitive Transcranial Magnetic Stimulation ◽  
Low Frequency ◽  
Event Related Potentials ◽  
Autism Spectrum ◽  
Event Related Potential ◽  
Sensory Stimuli ◽  
Related Potentials

AbstractIndividuals with autism spectrum disorder (ASD) have previously been shown to have significantly augmented and prolonged event-related potentials (ERP) to irrelevant visual stimuli compared to controls at both early and later stages (e.g., N200, P300) of visual processing and evidence of an overall lack of stimulus discrimination. Abnormally large and indiscriminative cortical responses to sensory stimuli may reflect cortical inhibitory deficits and a disruption in the excitation/inhibition ratio. Low-frequency (≤ 1HZ) repetitive transcranial magnetic stimulation (rTMS) has been shown to increase inhibition of stimulated cortex by the activation of inhibitory circuits. It was our prediction that after 12 sessions of low-frequency rTMS applied bilaterally to the dorsolateral prefrontal cortices in individuals with ASD there would be a significant improvement in ERP indices of selective attention evoked at later (i.e., 200–600 ms) stages of attentional processing as well as an improvement in motor response error rate. We assessed 25 participants with ASD in a task of selective attention using illusory figures before and after 12 sessions of rTMS in a controlled design where a waiting-list group of 20 children with ASD performed the same task twice. We found a significant improvement in both N200 and P300 components as a result of rTMS as well as a significant reduction in response errors. We also found significant reductions in both repetitive behavior and irritability according to clinical behavioral questionnaires as a result of rTMS. We propose that rTMS has the potential to become an important therapeutic tool in ASD research and treatment.

scholarly journals Hemispheric Asymmetry in Visual Processing: An Erp Study on Spatial Frequency Gratings

2021 ◽  
Author(s):  
Alice Mado Proverbio ◽  
and Alberto Zani
Keyword(s):  
Spatial Frequency ◽  
Visual Processing ◽  
Visual Information ◽  
Hemispheric Asymmetry ◽  
High Spatial Frequency ◽  
Event Related Potentials ◽  
Repeated Measure ◽  
Sensory Response ◽  
Visual Responses ◽  
Related Potentials

A hemispheric asymmetry is known for the processing of global vs. local visual information. In this study, we investigated the existence of a hemispheric asymmetry for visual processing of low vs. high spatial frequency gratings. Event-related potentials were recorded in a group of healthy right-handed volunteers from 30 scalp sites. Six types of stimuli (1.5, 3 and 6 c/deg gratings) were randomly flashed 180 times in the left and right upper hemi-fields. Stimulus duration was 80 ms and ISI ranged between 850-1000 ms. Participants had to pay attention and respond to targets based on their spatial frequency and location, or to passively look at the stimuli. C1 and P1 visual responses, as well as a later Selection negativity and a P300 components of ERPs were quantified and subjected to repeated-measure ANOVAs. Overall, performance was faster for the RVF, thus suggesting a left hemispheric advantage for attentional selection of local elements. Similarly, the analysis of mean area amplitude of C1 (60-110 ms) sensory response showed a stronger attentional effect (F+L+ vs. F-L+) at left occipital areas, thus suggesting the sensory nature of this hemispheric asymmetry.

Neural Mechanisms of Global and Local Processing: A Combined PET and ERP Study

1998 ◽  
Vol 10 (4) ◽  
pp. 485-498 ◽  
Author(s):  
H. J. Heinze ◽  
H. Hinrichs ◽  
M. Scholz ◽  
W. Burchert ◽  
G. R. Mangun
Keyword(s):  
Selective Attention ◽  
Divided Attention ◽  
Right Hemisphere ◽  
Event Related Potentials ◽  
Neural Mechanisms ◽  
Extrastriate Cortex ◽  
Hemispheric Differences ◽  
Related Potentials ◽  
Sensory Evoked ◽  
Global And Local

The neural mechanisms of hierarchical stimulus processing were investigated using a combined event-related potentials (ERPs) and positron emission tomography (PET) approach. Healthy subjects were tested under two conditions that involved selective or divided attention between local and global levels of hierarchical letter stimuli in order to determine whether and where hemispheric differences might exist in the processing of local versus global information. When attention was divided between global and local levels, the N2 component of the ERPs (260- to 360-msec latency) elicited by the target stimuli showed asymmetries in amplitude over the two hemispheres. The N2 to local targets was larger over the left hemisphere, but the N2 to global targets tended to be slightly larger over the right hemisphere. However, the shorter-latency, sensory-evoked P1 component (90- to 150-msec latency) was not different for global versus local targets under conditions of divided attention. In contrast, during selective attention to either global or local targets, asymmetries in the N2 component were not observed. But under selective attention conditions, the sensory-evoked P1 components in the extrastriate cortex were enlarged for global versus local attention. In- creased regional cerebral blood flow in the posterior fusiform gyrus bilaterally was observed in the PET data during selective attention to either global or local targets, but neither these nor the P1 component showed any tendency toward hemispheric difference for global versus local attention. Neither were there any activations observed in the parietal lobe during selective attention to global versus local targets. Together these data indicate that early sensory inputs are not modulated to gate global versus local information differentially into the two hemi- spheres. Rather, later stages of processing that may be asym- metrically organized in the left and right hemispheres operate in parallel to process global and local aspects of complex stimuli (i.e., the N2 effect of the ERPs). This pattern of results supports models proposing that spatial frequency analysis is only asymmetric at higher stages of perceptual processing and not at the earliest stages of visual cortical analysis.

scholarly journals Hemispheric Asymmetry in Visual Processing: An ERP Study on Spatial Frequency Gratings

Symmetry ◽  
2021 ◽  
Vol 13 (2) ◽  
pp. 180
Author(s):  
Alice Mado Proverbio ◽  
Alberto Zani
Keyword(s):  
Spatial Frequency ◽  
Visual Processing ◽  
Hemispheric Asymmetry ◽  
High Spatial Frequency ◽  
Event Related Potentials ◽  
Repeated Measure ◽  
Right Visual Field ◽  
Sensory Response ◽  
Visual Responses ◽  
Related Potentials

A hemispheric asymmetry for the processing of global versus local visual information is known. In this study, we investigated the existence of a hemispheric asymmetry for the visual processing of low versus high spatial frequency gratings. The event-related potentials were recorded in a group of healthy right-handed volunteers from 30 scalp sites. Six types of stimuli (1.5, 3 and 6 c/deg gratings) were randomly flashed 180 times in the left and right upper hemifields. The stimulus duration was 80 ms, and the interstimulus interval (ISI) ranged between 850 and 1000 ms. Participants paid attention and responded to targets based on their spatial frequency and location. The C1 and P1 visual responses, as well as a later selection negativity and a P300 component of event-related potentials (ERPs), were quantified and subjected to repeated-measure analyses of variance (ANOVAs). Overall, the performance was faster for the right visual field (RVF), thus suggesting a left hemispheric advantage for the attentional selection of local elements. Similarly, the analysis of the mean area amplitude of the C1 (60–110 ms) sensory response showed a stronger attentional effect (F+L+ vs. F−L+) at the left occipital areas, thus suggesting the sensory nature of this hemispheric asymmetry.

Event-Related Potentials During Memory Search and Selective Attention to Letter Size and Conjunctions of Letter Size and Color

1989 ◽  
Vol 26 (5) ◽  
pp. 529-547 ◽  
Author(s):  
Albertus A. Wijers ◽  
Gijsbertus Mulder ◽  
Tsunetaka Okita ◽  
Lambertus J.M. Mulder
Keyword(s):  
Selective Attention ◽  
Memory Search ◽  
Event Related Potentials ◽  
Related Potentials ◽  
Letter Size

scholarly journals A Neurophysiological Study of Semantic Processing in Parkinson’s Disease

2016 ◽  
Vol 23 (1) ◽  
pp. 78-89 ◽  
Author(s):  
Anthony J. Angwin ◽  
Nadeeka N.W. Dissanayaka ◽  
Alison Moorcroft ◽  
Katie L. McMahon ◽  
Peter A. Silburn ◽  
...  
Keyword(s):  
Parkinson’S Disease ◽  
Parkinson's Disease ◽  
Semantic Processing ◽  
Time Course ◽  
Event Related Potentials ◽  
Mean Amplitude ◽  
Repetition Effects ◽  
Related Potentials ◽  
The Mean ◽  
Written Word

AbstractObjectives: Cognitive-linguistic impairments in Parkinson’s disease (PD) have been well documented; however, few studies have explored the neurophysiological underpinnings of semantic deficits in PD. This study investigated semantic function in PD using event-related potentials. Methods: Eighteen people with PD and 18 healthy controls performed a semantic judgement task on written word pairs that were either congruent or incongruent. Results: The mean amplitude of the N400 for new incongruent word pairs was similar for both groups, however the onset latency was delayed in the PD group. Further analysis of the data revealed that both groups demonstrated attenuation of the N400 for repeated incongruent trials, as well as attenuation of the P600 component for repeated congruent trials. Conclusions: The presence of N400 congruity and N400 repetition effects in the PD group suggests that semantic processing is generally intact, but with a slower time course as evidenced by the delayed N400. Additional research will be required to determine whether N400 and P600 repetition effects are sensitive to further cognitive decline in PD. (JINS, 2017, 23, 78–89)

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