scholarly journals Impaired Fixation-Related Theta Modulation Predicts Reduced Visual Span and Guided Search Deficits in Schizophrenia

2020 ◽  
Vol 30 (5) ◽  
pp. 2823-2833 ◽  
Author(s):  
Elisa C Dias ◽  
Abraham C Van Voorhis ◽  
Filipe Braga ◽  
Julianne Todd ◽  
Javier Lopez-Calderon ◽  
...  
Keyword(s):  
Visual Processing ◽  
Search Strategy ◽  
Initial Study ◽  
Behavioral Performance ◽  
Search Performance ◽  
Phase Reset ◽  
Visual Span ◽  
Sensory Modalities ◽  
Theta Phase ◽  
Stimulus Features

Abstract During normal visual behavior, individuals scan the environment through a series of saccades and fixations. At each fixation, the phase of ongoing rhythmic neural oscillations is reset, thereby increasing efficiency of subsequent visual processing. This phase-reset is reflected in the generation of a fixation-related potential (FRP). Here, we evaluate the integrity of theta phase-reset/FRP generation and Guided Visual Search task in schizophrenia. Subjects performed serial and parallel versions of the task. An initial study (15 healthy controls (HC)/15 schizophrenia patients (SCZ)) investigated behavioral performance parametrically across stimulus features and set-sizes. A subsequent study (25-HC/25-SCZ) evaluated integrity of search-related FRP generation relative to search performance and evaluated visual span size as an index of parafoveal processing. Search times were significantly increased for patients versus controls across all conditions. Furthermore, significantly, deficits were observed for fixation-related theta phase-reset across conditions, that fully predicted impaired reduced visual span and search performance and correlated with impaired visual components of neurocognitive processing. By contrast, overall search strategy was similar between groups. Deficits in theta phase-reset mechanisms are increasingly documented across sensory modalities in schizophrenia. Here, we demonstrate that deficits in fixation-related theta phase-reset during naturalistic visual processing underlie impaired efficiency of early visual function in schizophrenia.

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.

How Interface Design and Search Strategy Influence Children’s Search Performance and Evaluation

2014 ◽  
pp. 241-287 ◽  
Author(s):  
Hanna Jochmann-Mannak ◽  
Leo Lentz ◽  
Theo Huibers ◽  
Ted Sanders
Keyword(s):  
Search Engine ◽  
Interface Design ◽  
Search Strategy ◽  
Emotional Valence ◽  
Affective Responses ◽  
Visual Design ◽  
Search Performance ◽  
Different Types ◽  
Navigation Structure ◽  
Performance And Evaluation

This chapter presents an experiment with 158 children, aged 10 to 12, in which search performance and attitudes towards an informational Website are investigated. The same Website was designed in 3 different types of interface design varying in playfulness of navigation structure and in playfulness of visual design. The type of interface design did not have an effect on children’s search performance, but it did influence children’s feelings of emotional valence and their evaluation of “goodness.” Children felt most positive about the Website with a classical navigation structure and playful aesthetics. They found the playful image map Website least good. More importantly, children’s search performance was much more effective and efficient when using the search engine than when browsing the menu. Furthermore, this chapter explores the challenge of measuring affective responses towards digital interfaces with children by presenting an elaborate evaluation of different methods.

scholarly journals Serotonergic modulation across sensory modalities

2020 ◽  
Vol 123 (6) ◽  
pp. 2406-2425
Author(s):  
Tyler R. Sizemore ◽  
Laura M. Hurley ◽  
Andrew M. Dacks
Keyword(s):  
Serotonin Receptor ◽  
Physiological State ◽  
Sensory Information ◽  
Specific Stimulus ◽  
Sensory Organization ◽  
Sensory Modalities ◽  
Multiple Levels ◽  
Stimulus Features ◽  
Ubiquitous Presence ◽  
Serotonergic Modulation

The serotonergic system has been widely studied across animal taxa and different functional networks. This modulatory system is therefore well positioned to compare the consequences of neuromodulation for sensory processing across species and modalities at multiple levels of sensory organization. Serotonergic neurons that innervate sensory networks often bidirectionally exchange information with these networks but also receive input representative of motor events or motivational state. This convergence of information supports serotonin’s capacity for contextualizing sensory information according to the animal’s physiological state and external events. At the level of sensory circuitry, serotonin can have variable effects due to differential projections across specific sensory subregions, as well as differential serotonin receptor type expression within those subregions. Functionally, this infrastructure may gate or filter sensory inputs to emphasize specific stimulus features or select among different streams of information. The near-ubiquitous presence of serotonin and other neuromodulators within sensory regions, coupled with their strong effects on stimulus representation, suggests that these signaling pathways should be considered integral components of sensory systems.

scholarly journals Auditory and visual scene analysis: an overview

2017 ◽  
Vol 372 (1714) ◽  
pp. 20160099 ◽  
Author(s):  
Hirohito M. Kondo ◽  
Anouk M. van Loon ◽  
Jun-Ichiro Kawahara ◽  
Brian C. J. Moore
Keyword(s):  
Scene Perception ◽  
Computational Modelling ◽  
Visual Scene ◽  
Scene Analysis ◽  
Theoretical Approaches ◽  
Visual Inputs ◽  
Sensory Modalities ◽  
Stimulus Features ◽  
The Brain ◽  
Selection Of

We perceive the world as stable and composed of discrete objects even though auditory and visual inputs are often ambiguous owing to spatial and temporal occluders and changes in the conditions of observation. This raises important questions regarding where and how ‘scene analysis’ is performed in the brain. Recent advances from both auditory and visual research suggest that the brain does not simply process the incoming scene properties. Rather, top-down processes such as attention, expectations and prior knowledge facilitate scene perception. Thus, scene analysis is linked not only with the extraction of stimulus features and formation and selection of perceptual objects, but also with selective attention, perceptual binding and awareness. This special issue covers novel advances in scene-analysis research obtained using a combination of psychophysics, computational modelling, neuroimaging and neurophysiology, and presents new empirical and theoretical approaches. For integrative understanding of scene analysis beyond and across sensory modalities, we provide a collection of 15 articles that enable comparison and integration of recent findings in auditory and visual scene analysis. This article is part of the themed issue ‘Auditory and visual scene analysis’.

scholarly journals Belief in Control: Voluntary Choice Enhances Subsequent Task Performance under Undefeated Choice-Outcome Causation

2021 ◽  
Author(s):  
Xiaoxiao Luo ◽  
Lihui Wang ◽  
xiaolin zhou
Keyword(s):  
Search Task ◽  
Behavioral Performance ◽  
Search Performance ◽  
Blank Screen ◽  
Subsequent Behavior ◽  
Series Of Experiments ◽  
Improved Performance ◽  
Voluntary Choice ◽  
Task Irrelevant ◽  
Subsequent Task

Humans are believed to have volition through which they act upon and change the external environment. As an exercise of volition, making a voluntary choice facilitates the subsequent behavioral performance relative to a forced choice. However, it is unclear how this facilitation is constrained by the perceived relationship between a choice and its outcome. In a series of experiments, participants were free or forced to choose one of two presented pictures. The outcome of the choice was then revealed, which could be always the chosen picture or always the unchosen picture (i.e., a confirmed choice-outcome causation), a blank screen with no picture at all (i.e., an unrevealed choice-outcome relation), the chosen or unchosen picture with equal probability (i.e., a defeated choice-outcome causation), or a third picture different from the two preceding options (again, a defeated choice-outcome causation). Participants then complete a visual search task with the task-irrelevant picture (or the blank screen) serving as a background. Results showed that the search performance was improved after a voluntary choice under both the confirmed causation and the unrevealed relation, but not under the defeated causation. Over individuals, the improved performance due to voluntary choice under confirmed causation positively correlated with the improved performance under the unrevealed relation, and with the reported belief in controlling the outcome of the choice. Our findings suggest that the exercise of volition motivates subsequent behavior, and this motivation is restricted to an “undefeated” choice-outcome causation which affords a belief in controlling the outcome by exerting volition.

scholarly journals Intrasaccadic motion streaks jump-start gaze correction

2021 ◽  
Vol 7 (30) ◽  
pp. eabf2218 ◽  
Author(s):  
Richard Schweitzer ◽  
Martin Rolfs
Keyword(s):  
Eye Movements ◽  
Visual Processing ◽  
Visual Information ◽  
High Speed ◽  
Target Motion ◽  
Object Correspondence ◽  
Visual Projection ◽  
Stimulus Features ◽  
Object Features ◽  
Gaze Correction

Rapid eye movements (saccades) incessantly shift objects across the retina. To establish object correspondence, the visual system is thought to match surface features of objects across saccades. Here, we show that an object’s intrasaccadic retinal trace—a signal previously considered unavailable to visual processing—facilitates this match making. Human observers made saccades to a cued target in a circular stimulus array. Using high-speed visual projection, we swiftly rotated this array during the eyes’ flight, displaying continuous intrasaccadic target motion. Observers’ saccades landed between the target and a distractor, prompting secondary saccades. Independently of the availability of object features, which we controlled tightly, target motion increased the rate and reduced the latency of gaze-correcting saccades to the initial presaccadic target, in particular when the target’s stimulus features incidentally gave rise to efficient motion streaks. These results suggest that intrasaccadic visual information informs the establishment of object correspondence and jump-starts gaze correction.

scholarly journals Strategies of the honeybee Apis mellifera during visual search for vertical targets presented at various heights: a role for spatial attention?

F1000Research ◽  
2014 ◽  
Vol 3 ◽  
pp. 174 ◽  
Author(s):  
Linde Morawetz ◽  
Lars Chittka ◽  
Johannes Spaethe
Keyword(s):  
Visual Field ◽  
Spatial Attention ◽  
Search Strategy ◽  
Poor Performance ◽  
Search Performance ◽  
Behavioural Adaptation ◽  
Straight Line ◽  
Search Patterns ◽  
Direct Flight ◽  
Learning Trials

When honeybees are presented with a colour discrimination task, they tend to choose swiftly and accurately when objects are presented in the ventral part of their frontal visual field. In contrast, poor performance is observed when objects appear in the dorsal part. Here we investigate if this asymmetry is caused by fixed search patterns or if bees can use alternative search mechanisms such as spatial attention, which allows flexible focusing on different areas of the visual field. We asked individual honeybees to choose an orange rewarded target among blue distractors. Target and distractors were presented in the ventral visual field, the dorsal field or both. Bees presented with targets in the ventral visual field consistently had the highest search efficiency, with rapid decisions, high accuracy and direct flight paths. In contrast, search performance for dorsally located targets was inaccurate and slow at the beginning of the test phase, but bees increased their search performance significantly after a few learning trials: they found the target faster, made fewer errors and flew in a straight line towards the target. However, bees needed thrice as long to improve the search for a dorsally located target when the target’s position changed randomly between the ventral and the dorsal visual field. We propose that honeybees form expectations of the location of the target’s appearance and adapt their search strategy accordingly. Different possible mechanisms of this behavioural adaptation are discussed.

Can we Train Humans to be Systematic Inspectors?

1998 ◽  
Vol 42 (16) ◽  
pp. 1165-1169 ◽  
Author(s):  
George M. Nickles ◽  
Valerie Sacrez ◽  
Anand K. Gramopadhye
Keyword(s):  
Search Strategy ◽  
Random Search ◽  
Systematic Search ◽  
Search Pattern ◽  
Search Performance ◽  
Inspection Task ◽  
Job Aid

Previous research in inspection has shown that a systematic search strategy is more effective than a random search strategy in looking for defects. Moreover, past studies have shown that training can improve search strategy. The purpose of this study was to determine if a job aid could be used to train inspectors to adopt a systematic search strategy and thereby improve their search performance. The study used a computer simulated inspection task and a job aid, which included a cursor that traced a systematic search pattern over the inspection surface represented by the screen. An experiment was designed wherein sixteen subjects were randomly assigned to two groups, those who received practice and instructions on the use of a systematic search strategy and those who received training on the job aid. The results are analyzed and reported

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