scholarly journals Visual search improvement in hemianopic patients after audio-visual stimulation

Brain ◽  
2005 ◽  
Vol 128 (12) ◽  
pp. 2830-2842 ◽  
Author(s):  
Nadia Bolognini ◽  
Fabrizio Rasi ◽  
Michela Coccia ◽  
Elisabetta Làdavas
Keyword(s):  
Visual Search ◽  
Visual Stimulation

scholarly journals “Blue Sky Effect”: Contextual Influences on Pupil Size During Naturalistic Visual Search

2021 ◽  
Vol 12 ◽  
Author(s):  
Steven M. Thurman ◽  
Russell A. Cohen Hoffing ◽  
Anna Madison ◽  
Anthony J. Ries ◽  
Stephen M. Gordon ◽  
...  
Keyword(s):  
Visual Search ◽  
Blue Light ◽  
Pupil Size ◽  
Visual Stimulation ◽  
Differential Sensitivity ◽  
Contextual Effect ◽  
Blue Color ◽  
Color Channel ◽  
The Gaze ◽  
Pupillary Responses

Pupil size is influenced by cognitive and non-cognitive factors. One of the strongest modulators of pupil size is scene luminance, which complicates studies of cognitive pupillometry in environments with complex patterns of visual stimulation. To help understand how dynamic visual scene statistics influence pupil size during an active visual search task in a visually rich 3D virtual environment (VE), we analyzed the correlation between pupil size and intensity changes of image pixels in the red, green, and blue (RGB) channels within a large window (~14 degrees) surrounding the gaze position over time. Overall, blue and green channels had a stronger influence on pupil size than the red channel. The correlation maps were not consistent with the hypothesis of a foveal bias for luminance, instead revealing a significant contextual effect, whereby pixels above the gaze point in the green/blue channels had a disproportionate impact on pupil size. We hypothesized this differential sensitivity of pupil responsiveness to blue light from above as a “blue sky effect,” and confirmed this finding with a follow-on experiment with a controlled laboratory task. Pupillary constrictions were significantly stronger when blue was presented above fixation (paired with luminance-matched gray on bottom) compared to below fixation. This effect was specific for the blue color channel and this stimulus orientation. These results highlight the differential sensitivity of pupillary responses to scene statistics in studies or applications that involve complex visual environments and suggest blue light as a predominant factor influencing pupil size.

scholarly journals Effects of Transient Loss of Vision on Head and Eye Movements during Visual Search in a Virtual Environment

2020 ◽  
Vol 10 (11) ◽  
pp. 841
Author(s):  
Erwan David ◽  
Julia Beitner ◽  
Melissa Le-Hoa Võ
Keyword(s):  
Virtual Reality ◽  
Visual Search ◽  
Eye Movements ◽  
Vision Loss ◽  
Peripheral Vision ◽  
Visual Stimulation ◽  
Past Research ◽  
Head Movements ◽  
Field Of View ◽  
The Impact

Central and peripheral fields of view extract information of different quality and serve different roles during visual tasks. Past research has studied this dichotomy on-screen in conditions remote from natural situations where the scene would be omnidirectional and the entire field of view could be of use. In this study, we had participants looking for objects in simulated everyday rooms in virtual reality. By implementing a gaze-contingent protocol we masked central or peripheral vision (masks of 6 deg. of radius) during trials. We analyzed the impact of vision loss on visuo-motor variables related to fixation (duration) and saccades (amplitude and relative directions). An important novelty is that we segregated eye, head and the general gaze movements in our analyses. Additionally, we studied these measures after separating trials into two search phases (scanning and verification). Our results generally replicate past on-screen literature and teach about the role of eye and head movements. We showed that the scanning phase is dominated by short fixations and long saccades to explore, and the verification phase by long fixations and short saccades to analyze. One finding indicates that eye movements are strongly driven by visual stimulation, while head movements serve a higher behavioral goal of exploring omnidirectional scenes. Moreover, losing central vision has a smaller impact than reported on-screen, hinting at the importance of peripheral scene processing for visual search with an extended field of view. Our findings provide more information concerning how knowledge gathered on-screen may transfer to more natural conditions, and attest to the experimental usefulness of eye tracking in virtual reality.

scholarly journals Visual search improvement in hemianopic patients after audio-visual stimulation

2006 ◽  
Vol 141 (2) ◽  
pp. 426-427
Author(s):  
N. Bolognini ◽  
F. Rasi ◽  
M. Coccia ◽  
E. Ladavas
Keyword(s):  
Visual Search ◽  
Visual Stimulation

Audio-Visual Stimulation Improves Visual Search Abilities in Hemianopia due to Childhood Acquired Brain Lesions

2015 ◽  
Vol 28 (1-2) ◽  
pp. 153-171 ◽  
Author(s):  
Francesca Tinelli ◽  
Giulia Purpura ◽  
Giovanni Cioni
Keyword(s):  
Visual Search ◽  
Visual Field ◽  
Superior Colliculus ◽  
Spontaneous Recovery ◽  
Visual Stimulation ◽  
Oculomotor System ◽  
Brain Lesions ◽  
Audiovisual Stimulation ◽  
Unilateral Brain

Results obtained in both animal models and hemianopic patients indicate that sound, spatially and temporally coincident with a visual stimulus, can improve visual perception in the blind hemifield, probably due to activation of ‘multisensory neurons’, mainly located in the superior colliculus. In view of this evidence, a new rehabilitation approach, based on audiovisual stimulation of visual field, has been proposed, and applied in adults with visual field reduction due to unilateral brain lesions. So far, results have been very encouraging, with improvements in visual search abilities. Based on these findings, we have investigated the possibility of inducing long-lasting amelioration also in children with a visual deficit due to acquired brain lesions. Our results suggest that, in the absence of spontaneous recovery, audiovisual training can induce activation of visual responsiveness of the oculomotor system also in children and adolescents with acquired lesions and confirm the putatively important role of the superior colliculus (SC) in this process.

The Influences of Goal and Laterality of a Prepared Hand Response on a Co-Occurring Visual Search

2015 ◽  
Vol 74 (1) ◽  
pp. 55-60 ◽  
Author(s):  
Alexandre Coutté ◽  
Gérard Olivier ◽  
Sylvane Faure
Keyword(s):  
Visual Search ◽  
Visual Target ◽  
Motor Planning ◽  
Search Performance ◽  
Response Preparation ◽  
Manual Response ◽  
Response Hand ◽  
Computer Screen ◽  
Left Hand ◽  
Manual Interaction

Computer use generally requires manual interaction with human-computer interfaces. In this experiment, we studied the influence of manual response preparation on co-occurring shifts of attention to information on a computer screen. The participants were to carry out a visual search task on a computer screen while simultaneously preparing to reach for either a proximal or distal switch on a horizontal device, with either their right or left hand. The response properties were not predictive of the target’s spatial position. The results mainly showed that the preparation of a manual response influenced visual search: (1) The visual target whose location was congruent with the goal of the prepared response was found faster; (2) the visual target whose location was congruent with the laterality of the response hand was found faster; (3) these effects have a cumulative influence on visual search performance; (4) the magnitude of the influence of the response goal on visual search is marginally negatively correlated with the rapidity of response execution. These results are discussed in the general framework of structural coupling between perception and motor planning.

Scientific Problem Solving in a Virtual Laboratory: A Comparison Between Individuals and Pairs

2008 ◽  
Vol 67 (2) ◽  
pp. 71-83 ◽  
Author(s):  
Yolanda A. Métrailler ◽  
Ester Reijnen ◽  
Cornelia Kneser ◽  
Klaus Opwis
Keyword(s):  
Visual Search ◽  
Problem Solving ◽  
Process Data ◽  
Scientific Problem ◽  
Domain Specific ◽  
Scientific Problem Solving ◽  
Before And After ◽  
Verbal Data ◽  
Psychological Knowledge ◽  
Problem Solving Task

This study compared individuals with pairs in a scientific problem-solving task. Participants interacted with a virtual psychological laboratory called Virtue to reason about a visual search theory. To this end, they created hypotheses, designed experiments, and analyzed and interpreted the results of their experiments in order to discover which of five possible factors affected the visual search process. Before and after their interaction with Virtue, participants took a test measuring theoretical and methodological knowledge. In addition, process data reflecting participants’ experimental activities and verbal data were collected. The results showed a significant but equal increase in knowledge for both groups. We found differences between individuals and pairs in the evaluation of hypotheses in the process data, and in descriptive and explanatory statements in the verbal data. Interacting with Virtue helped all students improve their domain-specific and domain-general psychological knowledge.

Visual Search Facilitation in Repeated Displays Depends on Visuospatial Working Memory

2012 ◽  
Vol 59 (1) ◽  
pp. 47-54 ◽  
Author(s):  
Angela A. Manginelli ◽  
Franziska Geringswald ◽  
Stefan Pollmann
Keyword(s):  
Working Memory ◽  
Visual Search ◽  
Control Experiment ◽  
Memory Load ◽  
Contextual Cueing ◽  
Long Term Memory ◽  
Visuospatial Working Memory ◽  
Working Memory Load ◽  
Memory Resources

When distractor configurations are repeated over time, visual search becomes more efficient, even if participants are unaware of the repetition. This contextual cueing is a form of incidental, implicit learning. One might therefore expect that contextual cueing does not (or only minimally) rely on working memory resources. This, however, is debated in the literature. We investigated contextual cueing under either a visuospatial or a nonspatial (color) visual working memory load. We found that contextual cueing was disrupted by the concurrent visuospatial, but not by the color working memory load. A control experiment ruled out that unspecific attentional factors of the dual-task situation disrupted contextual cueing. Visuospatial working memory may be needed to match current display items with long-term memory traces of previously learned displays.

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