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.

Investigating the role of the superior colliculus in active vision with the visual search paradigm

2011 ◽  
Vol 33 (11) ◽  
pp. 2003-2016 ◽  
Author(s):  
Kelly Shen ◽  
Jerome Valero ◽  
Gregory S. Day ◽  
Martin Paré
Keyword(s):  
Visual Search ◽  
Superior Colliculus ◽  
Active Vision

Role of striate cortex and superior colliculus in visual guidance of saccadic eye movements in monkeys

1977 ◽  
Vol 40 (1) ◽  
pp. 74-94 ◽  
Author(s):  
C. W. Mohler ◽  
R. H. Wurtz
Keyword(s):  
Eye Movements ◽  
Visual Field ◽  
Superior Colliculus ◽  
Stimulus Intensity ◽  
Macaca Mulatta ◽  
Striate Cortex ◽  
Visual Stimuli ◽  
Saccadic Eye Movements ◽  
Visual Guidance

1. We studied the effect of lesions placed in striate cortex or superior colliculus on the detection of visual stimuli and the accuracy of saccadic eye movements. The monkeys (Macaca mulatta) first learned to respond to a 0.25 degrees spot of light flashed for 150-200 ms in one part of the visual field while they were fixating in order to determine if they could detect the light. The monkeys also learned in a different task to make a saccade to the spot of light when the fixation point went out, and the accuracy of the saccades was measured. 2. Following a unilateral partial ablation of the striate cortex in two monkeys they could not detect the spot of light in the resulting scotoma or saccade to it. The deficit was only relative; if we increased the brightness of the stimulus from the usual 11 cd/m2 to 1,700 cd/m2 against a background of 1 cd/m2 the monkeys were able to detect and to make a saccade to the spot of light. 3. Following about 1 mo of practice on the detection and saccade tasks, the monkeys recovered the ability to detect the spots of light and to make saccades to them without gross errors (saccades made beyond an area of +/-3 average standard deviations). Lowering the stimulus intensity reinstated both the detection and saccadic errors...

scholarly journals Activity in V4 Reflects the Direction, But Not the Latency, of Saccades During Visual Search

2010 ◽  
Vol 104 (4) ◽  
pp. 2187-2193 ◽  
Author(s):  
Angela L. Gee ◽  
Anna E. Ipata ◽  
Michael E. Goldberg
Keyword(s):  
Visual Search ◽  
Eye Movements ◽  
Eye Movement ◽  
Spatial Attention ◽  
Oculomotor System ◽  
Area V4 ◽  
Processing Activity ◽  
Feature Information ◽  
Precise Role

We constantly make eye movements to bring objects of interest onto the fovea for more detailed processing. Activity in area V4, a prestriate visual area, is enhanced at the location corresponding to the target of an eye movement. However, the precise role of activity in V4 in relation to these saccades and the modulation of other cortical areas in the oculomotor system remains unknown. V4 could be a source of visual feature information used to select the eye movement, or alternatively, it could reflect the locus of spatial attention. To test these hypotheses, we trained monkeys on a visual search task in which they were free to move their eyes. We found that activity in area V4 reflected the direction of the upcoming saccade but did not predict the latency of the saccade in contrast to activity in the lateral intraparietal area (LIP). We suggest that the signals in V4, unlike those in LIP, are not directly involved in the generation of the saccade itself but rather are more closely linked to visual perception and attention. Although V4 and LIP have different roles in spatial attention and preparing eye movements, they likely perform complimentary processes during visual search.

The Psychologist-Educator Views the Relationship of Vision to Reading and Related Learning Disabilities

1981 ◽  
Vol 14 (10) ◽  
pp. 565-567 ◽  
Author(s):  
Jules C. Abrams
Keyword(s):  
Learning Disabilities ◽  
Visual Field ◽  
Visual Perception ◽  
Learning Disability ◽  
Visual Defects ◽  
Considerable Controversy ◽  
Visual Problems ◽  
Relationship Of ◽  
The Relationship

The role of visual problems in learning disability has been a source of considerable controversy for many years. One major issue in the continuing argument is the frequent confusion of labels and concepts in the visual field. It is important to view vision as a psychophysiologic mechanism and to differentiate it from a mechanistic orientation emphasizing the eyes. Most visual problems related to learning disability represent a breakdown in the ability of the eyes to function in an harmonious fashion, that is, some interference in binocular function. While visual defects should not be confused with defects in visual perception, the identification and treatment of visual problems is an important element in the diagnosis and remediation of learning disabilities.

scholarly journals The role of memory for visual search in scenes

2015 ◽  
Vol 1339 (1) ◽  
pp. 72-81 ◽  
Author(s):  
Melissa Le-Hoa Võ ◽  
Jeremy M. Wolfe
Keyword(s):  
Visual Search
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