scholarly journals Lateral interactions in schizophrenia: What is the role of spatial frequency?

2014 ◽  
Vol 14 (10) ◽  
pp. 55-55
Author(s):  
B. Keane ◽  
S. Kastner ◽  
D. Paterno ◽  
G. Erlikhman ◽  
S. Silverstein
Keyword(s):  
Spatial Frequency ◽  
Lateral Interactions

Fading of Textured Targets on Textured Background

Perception ◽  
1997 ◽  
Vol 26 (1_suppl) ◽  
pp. 5-5
Author(s):  
R Teichmann ◽  
L Spillmann
Keyword(s):  
Visual Field ◽  
Spatial Frequency ◽  
Random Order ◽  
Lateral Interactions ◽  
Target Orientation ◽  
Neuronal Process ◽  
Low Contrast ◽  
Orientation Contrast ◽  
Fading Time

In 1804 Troxler reported that with strict fixation, a small, low-contrast target presented to the peripheral visual field will tend to fade and ultimately become invisible. Further studies have shown that, in addition to stationary targets, moving and flickering targets will also fade. We studied the role of a texture difference between the target and its background on fading. We found that textured targets fade as quickly as, or even faster than, uniform targets. Typically, the target becomes less salient and after a while disappears in the background. Specifically, we asked whether orientation contrast would influence the time of perceptual disappearance. A grating disk of 2 deg diameter and 0.8 cycle deg−1 spatial frequency was presented binocularly on an equally striped background, 15 deg from the fixation point. The orientation of the target relative to that of the background was varied in steps of 15°, yielding eleven stimuli which were presented in a random order. Each orientation was shown a total of nine times. Luminance, spatial frequency, and contrast were the same for both the target and the background. Time to fading was measured for each target orientation. The results show that orientation contrast strongly affects fading. Time to fading was longest when the grating target and the background were oriented at right angles and decreased symmetrically with decreasing orientation contrast. This result supports the hypothesis that fading is an active neuronal process of long-range lateral interactions.

Role of intrathalamic inhibition on the spatial frequency tuning of neurons in the lateral geniculate nucleus of the cat

2009 ◽  
Vol 65 ◽  
pp. S106
Author(s):  
Akihiro Kimura ◽  
Satoshi Shimegi ◽  
Shin-ichiro Hara ◽  
Masahiro Okamoto ◽  
Hiromichi Sato
Keyword(s):  
Spatial Frequency ◽  
Lateral Geniculate Nucleus ◽  
Frequency Tuning ◽  
Spatial Frequency Tuning ◽  
Lateral Geniculate

scholarly journals Examining the role of red background in magnocellular contribution to face perception

2015 ◽  
Author(s):  
Bhuvanesh Awasthi ◽  
Mark A Williams ◽  
Jason Friedman
Keyword(s):  
Spatial Frequency ◽  
Face Perception ◽  
Red Light ◽  
Specific Property ◽  
High Spatial Frequency ◽  
Arm Movement ◽  
Frequency Component ◽  
Behavioral Evidence ◽  
Movement Curvature

This study examines the role of the magnocellular system in the early stages of face perception, in particular sex categorization. Utilizing the specific property of magnocellular suppression in red light, we investigated visually guided reaching to low and high spatial frequency hybrid faces against red and grey backgrounds. The arm movement curvature measure shows that reduced response of the magnocellular pathway interferes with the low spatial frequency component of face perception. This is the first definitive behavioral evidence for magnocellular contribution to face perception.

scholarly journals A Neural Model of Figure–Ground Organization

2007 ◽  
Vol 97 (6) ◽  
pp. 4310-4326 ◽  
Author(s):  
Edward Craft ◽  
Hartmut Schütze ◽  
Ernst Niebur ◽  
Rüdiger von der Heydt
Keyword(s):  
Neural Circuits ◽  
Neural Model ◽  
Self Organization ◽  
Lateral Interactions ◽  
Early Visual Cortex ◽  
Experimental Findings ◽  
Psychophysical Studies ◽  
Contour Grouping ◽  
Ground Organization

Psychophysical studies suggest that figure–ground organization is a largely autonomous process that guides—and thus precedes—allocation of attention and object recognition. The discovery of border-ownership representation in single neurons of early visual cortex has confirmed this view. Recent theoretical studies have demonstrated that border-ownership assignment can be modeled as a process of self-organization by lateral interactions within V2 cortex. However, the mechanism proposed relies on propagation of signals through horizontal fibers, which would result in increasing delays of the border-ownership signal with increasing size of the visual stimulus, in contradiction with experimental findings. It also remains unclear how the resulting border-ownership representation would interact with attention mechanisms to guide further processing. Here we present a model of border-ownership coding based on dedicated neural circuits for contour grouping that produce border-ownership assignment and also provide handles for mechanisms of selective attention. The results are consistent with neurophysiological and psychophysical findings. The model makes predictions about the hypothetical grouping circuits and the role of feedback between cortical areas.

scholarly journals Role of the illumination spatial-frequency spectrum for ptychography

2012 ◽  
Vol 86 (10) ◽  
Author(s):  
Manuel Guizar-Sicairos ◽  
Mirko Holler ◽  
Ana Diaz ◽  
Joan Vila-Comamala ◽  
Oliver Bunk ◽  
...  
Keyword(s):  
Spatial Frequency ◽  
Frequency Spectrum ◽  
Spatial Frequency Spectrum

“Weber's law” for position: the role of spatial frequency and contrast

1992 ◽  
Vol 32 (12) ◽  
pp. 2235-2250 ◽  
Author(s):  
Dennis M. Levi ◽  
Stanley A. Klein
Keyword(s):  
Spatial Frequency ◽  
Weber’S Law ◽  
Weber's Law

scholarly journals The role of local separation in spatial frequency discrimination

2012 ◽  
Vol 53 (1) ◽  
pp. 15-20 ◽  
Author(s):  
Andrew J. Anderson ◽  
Sarah E. Wassnig
Keyword(s):  
Spatial Frequency ◽  
Frequency Discrimination
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