scholarly journals Dichoptic Collinear Lateral Masking at Long Stimulus Onset Asynchronies Produces Surprising Suppression of Contrast Detection

2012 ◽  
Vol 12 (9) ◽  
pp. 99-99
Author(s):  
W. Kinerk ◽  
M. Martorana ◽  
E. Wong
Keyword(s):  
Stimulus Onset ◽  
Lateral Masking ◽  
Contrast Detection

Long-Lasting Detection Facilitation Induced by Gabor Flankers

Perception ◽  
1996 ◽  
Vol 25 (1_suppl) ◽  
pp. 155-155
Author(s):  
Y Tanaka ◽  
D Sagi
Keyword(s):  
Time Course ◽  
Detection Threshold ◽  
Stimulus Onset ◽  
Long Term Memory ◽  
High Contrast ◽  
Spatial Filters ◽  
Contrast Detection ◽  
Separation Threshold ◽  
Sensitivity Changes

Contrast detection threshold of a Gabor signal (GS) is enhanced in the presence of high contrast GS flankers. Repetitive performance of the task induces contrast sensitivity changes on different time scales: minutes when using mental imagery, and weeks in the context of perceptual learning. We tested the time course of lateral enhancement within a single trial, using a forward masking technique. Contrast detection thresholds were measured (2AFC) for a foveal GS target presented briefly (32 ms) preceded by a presentation (80 ms) of two high-contrast GS flankers, with stimulus onset asynchrony (SOA) varying from 0 to 3600 ms. Using target-to-mask separation of 3\lambda and 12\lambda (\lambda =18°, GS wavelength), we found that the 3\lambda separation GS flankers decreased target threshold by 0.25 log units at SOA=0 and by 0.17 log units at 3600 ms. At 12\lambda separation, threshold decreased by 0.11 log units at SOA=0 and by 0.14 log units at 3600 ms. Long-term and short-term enhancements showed similar dependence on stimulus configuration (maximal for collinear target and masks) and local parameters (orientation and spatial frequency differences between target and flankers). The results imply that spatial filters in early vision retain an input trace for as long as a few seconds (up to 14.4 seconds tested). This trace may subserve the consolidation of filter activity into long-term memory.

Focusing of Visuospatial Attention

2001 ◽  
Vol 15 (4) ◽  
pp. 256-274 ◽  
Author(s):  
Caterina Pesce ◽  
Rainer Bösel
Keyword(s):  
Reaction Times ◽  
Visual Space ◽  
Spatial Relation ◽  
Stimulus Onset ◽  
Visuospatial Attention ◽  
Task Demands ◽  
Time Interval ◽  
Behavioral Studies ◽  
Task Conditions ◽  
Simple Rt

Abstract In the present study we explored the focusing of visuospatial attention in subjects practicing and not practicing activities with high attentional demands. Similar to the studies of Castiello and Umiltà (e. g., 1990) , our experimental procedure was a variation of Posner's (1980) basic paradigm for exploring covert orienting of visuospatial attention. In a simple RT-task, a peripheral cue of varying size was presented unilaterally or bilaterally from a central fixation point and followed by a target at different stimulus-onset-asynchronies (SOAs). The target could occur validly inside the cue or invalidly outside the cue with varying spatial relation to its boundary. Event-related brain potentials (ERPs) and reaction times (RTs) were recorded to target stimuli under the different task conditions. RT and ERP findings showed converging aspects as well as dissociations. Electrophysiological results revealed an amplitude modulation of the ERPs in the early and late Nd time interval at both anterior and posterior scalp sites, which seems to be related to the effects of peripheral informative cues as well as to the attentional expertise. Results were: (1) shorter latency effects confirm the positive-going amplitude enhancement elicited by unilateral peripheral cues and strengthen the criticism against the neutrality of spatially nonpredictive peripheral cueing of all possible target locations which is often presumed in behavioral studies. (2) Longer latency effects show that subjects with attentional expertise modulate the distribution of the attentional resources in the visual space differently than nonexperienced subjects. Skilled practice may lead to minimizing attentional costs by automatizing the use of a span of attention that is adapted to the most frequent task demands and endogenously increases the allocation of resources to cope with less usual attending conditions.

Orienting and Focusing in Voluntary and Involuntary Visuospatial Attention Conditions

2010 ◽  
Vol 24 (3) ◽  
pp. 198-209 ◽  
Author(s):  
Yan Wang ◽  
Jianhui Wu ◽  
Shimin Fu ◽  
Yuejia Luo
Keyword(s):  
Gain Control ◽  
Event Related Potentials ◽  
Stimulus Onset ◽  
Orientation Discrimination ◽  
Involuntary Attention ◽  
Attention Condition ◽  
Voluntary Attention ◽  
Visual Spatial ◽  
Related Potentials ◽  
Underlying Mechanisms

In the present study, we used event-related potentials (ERPs) and behavioral measurements in a peripherally cued line-orientation discrimination task to investigate the underlying mechanisms of orienting and focusing in voluntary and involuntary attention conditions. Informative peripheral cue (75% valid) with long stimulus onset asynchrony (SOA) was used in the voluntary attention condition; uninformative peripheral cue (50% valid) with short SOA was used in the involuntary attention condition. Both orienting and focusing were affected by attention type. Results for attention orienting in the voluntary attention condition confirmed the “sensory gain control theory,” as attention enhanced the amplitude of the early ERP components, P1 and N1, without latency changes. In the involuntary attention condition, compared with invalid trials, targets in the valid trials elicited larger and later contralateral P1 components, and smaller and later contralateral N1 components. Furthermore, but only in the voluntary attention condition, targets in the valid trials elicited larger N2 and P3 components than in the invalid trials. Attention focusing in the involuntary attention condition resulted in larger P1 components elicited by targets in small-cue trials compared to large-cue trials, whereas in the voluntary attention condition, larger P1 components were elicited by targets in large-cue trials than in small-cue trials. There was no interaction between orienting and focusing. These results suggest that orienting and focusing of visual-spatial attention are deployed independently regardless of attention type. In addition, the present results provide evidence of dissociation between voluntary and involuntary attention during the same task.

Emotional Reactivity to Visual Content as Revealed by ERP Component Clustering

2015 ◽  
Vol 29 (4) ◽  
pp. 135-146 ◽  
Author(s):  
Miroslaw Wyczesany ◽  
Szczepan J. Grzybowski ◽  
Jan Kaiser
Keyword(s):  
Emotional Reactivity ◽  
Brain Activity ◽  
Affective State ◽  
Occipital Lobe ◽  
Stimulus Onset ◽  
Emotional States ◽  
Neural Basis ◽  
Temporoparietal Junction ◽  
The Right ◽  
The Impact

Abstract. In the study, the neural basis of emotional reactivity was investigated. Reactivity was operationalized as the impact of emotional pictures on the self-reported ongoing affective state. It was used to divide the subjects into high- and low-responders groups. Independent sources of brain activity were identified, localized with the DIPFIT method, and clustered across subjects to analyse the visual evoked potentials to affective pictures. Four of the identified clusters revealed effects of reactivity. The earliest two started about 120 ms from the stimulus onset and were located in the occipital lobe and the right temporoparietal junction. Another two with a latency of 200 ms were found in the orbitofrontal and the right dorsolateral cortices. Additionally, differences in pre-stimulus alpha level over the visual cortex were observed between the groups. The attentional modulation of perceptual processes is proposed as an early source of emotional reactivity, which forms an automatic mechanism of affective control. The role of top-down processes in affective appraisal and, finally, the experience of ongoing emotional states is also discussed.

Combining the Post-Cue Task and the Perceptual Identification Task to Assess Parallel Activation and Mutual Facilitation of Related Primes and Targets

2018 ◽  
Vol 65 (2) ◽  
pp. 84-97 ◽  
Author(s):  
Demian Scherer ◽  
Dirk Wentura
Keyword(s):  
Semantic Priming ◽  
Stimulus Onset ◽  
The Other ◽  
Perceptual Identification ◽  
Identification Task ◽  
Priming Effects ◽  
Priming Paradigm ◽  
Parallel Activation ◽  
Prime Target

Abstract. Recent theories assume a mutual facilitation in case of semantic overlap for concepts being activated simultaneously. We provide evidence for this claim using a semantic priming paradigm. To test for mutual facilitation of related concepts, a perceptual identification task was employed, presenting prime-target pairs briefly and masked, with an SOA of 0 ms (i.e., prime and target were presented concurrently, one above the other). Participants were instructed to identify the target. In Experiment 1, a cue defining the target was presented at stimulus onset, whereas in Experiment 2 the cue was not presented before the offset of stimuli. Accordingly, in Experiment 2, a post-cue task was merged with the perceptual identification task. We obtained significant semantic priming effects in both experiments. This result is compatible with the view that two concepts can both be activated in parallel and can mutually facilitate each other if they are related.

Stimulus onset-to-onset time determines the dichotic temporal order threshold

2001 ◽  
Author(s):  
Harvey Babkoff ◽  
Elisheva Ben-Artzi ◽  
Leah Fostick
Keyword(s):  
Temporal Order ◽  
Onset Time ◽  
Stimulus Onset
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