Temporal Analysis of Visual Search Task by Transcranial Magnetic Stimulation

PIERS Online ◽  
2007 ◽  
Vol 3 (1) ◽  
pp. 111-113
Author(s):  
Sheng Ge ◽  
Shoogo Ueno ◽  
Keiji Iramina
Keyword(s):  
Visual Search ◽  
Transcranial Magnetic Stimulation ◽  
Magnetic Stimulation ◽  
Search Task ◽  
Visual Search Task ◽  
Temporal Analysis

Far-space neglect in conjunction but not feature search following transcranial magnetic stimulation over right posterior parietal cortex

2014 ◽  
Vol 111 (4) ◽  
pp. 705-714 ◽  
Author(s):  
Indra T. Mahayana ◽  
Chia-Lun Liu ◽  
Chi Fu Chang ◽  
Daisy L. Hung ◽  
Ovid J. L. Tzeng ◽  
...  
Keyword(s):  
Visual Search ◽  
Transcranial Magnetic Stimulation ◽  
Parietal Cortex ◽  
Magnetic Stimulation ◽  
Posterior Parietal Cortex ◽  
Search Task ◽  
Association Cortex ◽  
Feature Search ◽  
Posterior Parietal

Near- and far-space coding in the human brain is a dynamic process. Areas in dorsal, as well as ventral visual association cortex, including right posterior parietal cortex (rPPC), right frontal eye field (rFEF), and right ventral occipital cortex (rVO), have been shown to be important in visuospatial processing, but the involvement of these areas when the information is in near or far space remains unclear. There is a need for investigations of these representations to help explain the pathophysiology of hemispatial neglect, and the role of near and far space is crucial to this. We used a conjunction visual search task using an elliptical array to investigate the effects of transcranial magnetic stimulation delivered over rFEF, rPPC, and rVO on the processing of targets in near and far space and at a range of horizontal eccentricities. As in previous studies, we found that rVO was involved in far-space search, and rFEF was involved regardless of the distance to the array. It was found that rPPC was involved in search only in far space, with a neglect-like effect when the target was located in the most eccentric locations. No effects were seen for any site for a feature search task. As the search arrays had higher predictability with respect to target location than is often the case, these data may form a basis for clarifying both the role of PPC in visual search and its contribution to neglect, as well as the importance of near and far space in these.

Obsessive–compulsive disorder patients display enhanced latent inhibition on a visual search task

2006 ◽  
Vol 44 (8) ◽  
pp. 1137-1145 ◽  
Author(s):  
Oren Kaplan ◽  
Reuven Dar ◽  
Lirona Rosenthal ◽  
Haggai Hermesh ◽  
Mendel Fux ◽  
...  
Keyword(s):  
Visual Search ◽  
Obsessive Compulsive Disorder ◽  
Latent Inhibition ◽  
Search Task ◽  
Visual Search Task ◽  
Obsessive Compulsive ◽  
Compulsive Disorder

Effect of parietal lobe lesions on saccade targeting and spatial memory in a naturalistic visual search task

2003 ◽  
Vol 41 (10) ◽  
pp. 1365-1386 ◽  
Author(s):  
Steven S. Shimozaki ◽  
Mary M. Hayhoe ◽  
Gregory J. Zelinsky ◽  
Amy Weinstein ◽  
William H. Merigan ◽  
...  
Keyword(s):  
Visual Search ◽  
Spatial Memory ◽  
Search Task ◽  
Visual Search Task ◽  
Parietal Lobe

Effects of unilateral frontal eye-field lesions on eye-head coordination in monkey

1986 ◽  
Vol 55 (4) ◽  
pp. 696-714 ◽  
Author(s):  
J. van der Steen ◽  
I. S. Russell ◽  
G. O. James
Keyword(s):  
Visual Search ◽  
Search Task ◽  
Visual Search Task ◽  
Peak Velocity ◽  
Head Movements ◽  
Frontal Eye Field ◽  
Behavioral Task ◽  
Direct Gaze ◽  
Relative Neglect ◽  
Eye Field

We studied the effects of unilateral frontal eye-field (FEF) lesions on eye-head coordination in monkeys that were trained to perform a visual search task. Eye and head movements were recorded with the scleral search coil technique using phase angle detection in a homogeneous electromagnetic field. In the visual search task all three animals showed a neglect for stimuli presented in the field contralateral to the lesion. In two animals the neglect disappeared within 2-3 wk. One animal had a lasting deficit. We found that FEF lesions that are restricted to area 8 cause only temporary deficits in eye and head movements. Up to a week after the lesion the animals had a strong preference to direct gaze and head to the side ipsilateral to the lesion. Animals tracked objects in contralateral space with combined eye and head movements, but failed to do this with the eyes alone. It was found that within a few days after the lesion, eye and head movements in the direction of the target were initiated, but they were inadequate and had long latencies. Within 1 wk latencies had regained preoperative values. Parallel with the recovery on the behavioral task, head movements became more prominent than before the lesion. Four weeks after the lesion, peak velocity of the head movement had increased by a factor of two, whereas the duration showed a twofold decrease compared with head movements before the lesion. No effects were seen on the duration and peak velocity of gaze. After the recovery on the behavioral task had stabilized, a relative neglect in the hemifield contralateral to the lesion could still be demonstrated by simultaneously presenting two stimuli in the left and right visual hemifields. The neglect is not due to a sensory deficit, but to a disorder of programming. The recovery from unilateral neglect after a FEF lesion is the result of a different orienting behavior, in which head movements become more important. It is concluded that the FEF plays an important role in the organization and coordination of eye and head movements and that lesions of this area result in subtle but permanent changes in eye-head coordination.

There is No Evidence That Kanizsa-Type Subjective Contours Can Be Detected in Parallel

Perception ◽  
1996 ◽  
Vol 25 (7) ◽  
pp. 861-874 ◽  
Author(s):  
Rick Gurnsey ◽  
Frédéric J A M Poirier ◽  
Eric Gascon
Keyword(s):  
Visual Search ◽  
Control Problem ◽  
Search Task ◽  
Visual Search Task ◽  
Physiological Data ◽  
Sufficient Information ◽  
Parallel Search ◽  
High Contrast ◽  
Psychophysical Data ◽  
Area V2

Davis and Driver presented evidence suggesting that Kanizsa-type subjective contours could be detected in a visual search task in a time that is independent of the number of nonsubjective contour distractors. A linking connection was made between these psychophysical data and the physiological data of Peterhans and von der Heydt which showed that cells in primate area V2 respond to subjective contours in the same way that they respond to luminance-defined contours. Here in three experiments it is shown that there was sufficient information in the displays used by Davis and Driver to support parallel search independently of whether subjective contours were present or not. When confounding properties of the stimuli were eliminated search became slow whether or not subjective contours were present in the display. One of the slowest search conditions involved stimuli that were virtually identical to those used in the physiological studies of Peterhans and von der Heydt to which Davis and Driver wish to link their data. It is concluded that while subjective contours may be represented in the responses of very early visual mechanisms (eg in V2) access to these representations is impaired by high-contrast contours used to induce the subjective contours and nonsubjective figure distractors. This persistent control problem continues to confound attempts to show that Kanizsa-type subjective contours can be detected in parallel.

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