Spatial Frequency Selectivity of a Visual Tilt Illusion

Nature ◽  
1973 ◽  
Vol 245 (5419) ◽  
pp. 43-45 ◽  
Author(s):  
MARK A. GEORGESON
Keyword(s):  
Spatial Frequency ◽  
Frequency Selectivity ◽  
Tilt Illusion

The effects of contrast on visual orientation and spatial frequency discrimination: a comparison of single cells and behavior

1987 ◽  
Vol 57 (3) ◽  
pp. 773-786 ◽  
Author(s):  
B. C. Skottun ◽  
A. Bradley ◽  
G. Sclar ◽  
I. Ohzawa ◽  
R. D. Freeman
Keyword(s):  
Spatial Frequency ◽  
Striate Cortex ◽  
Frequency Tuning ◽  
Single Cells ◽  
Frequency Discrimination ◽  
Frequency Selectivity ◽  
Response Amplitude ◽  
Visual Orientation ◽  
Characteristic Analysis ◽  
Response Variance

We have compared the effects of contrast on human psychophysical orientation and spatial frequency discrimination thresholds and on the responses of individual neurons in the cat's striate cortex. Contrast has similar effects on orientation and spatial frequency discrimination: as contrast is increased above detection threshold, orientation and spatial frequency discrimination performance improves but reaches maximum levels at quite low contrasts. Further increases in contrast produce no further improvements in discrimination. We measured the effects of contrast on response amplitude, orientation and spatial frequency selectivity, and response variance of neurons in the cat's striate cortex. Orientation and spatial frequency selectivity vary little with contrast. Also, the ratio of response variance to response mean is unaffected by contrast. Although, in many cells, response amplitude increases approximately linearly with log contrast over most of the visible range, some cells show complete or partial saturation of response amplitude at medium contrasts. Therefore, some cells show a clear increase in slope of the orientation and spatial frequency tuning functions with increasing contrast, whereas in others the slopes reach maximum values at medium contrasts. Using receiver operating characteristic analysis, we estimated the minimum orientation and spatial frequency differences that can be signaled reliably as a response change by an individual cell. This analysis shows that, on average, the discrimination of orientation or spatial frequency improves with contrast at low contrasts more than at higher contrasts. Using the optimal stimulus for each cell, we estimated the contrast threshold of 48 neurons. Most cells had contrast thresholds below 5%. Thresholds were only slightly higher for nonoptimal stimuli. Therefore, increasing the contrast of sinusoidal gratings above approximately 10% will not produce large increases in the number of responding cells. The observed effects of contrast on the response characteristics of nonsaturating cortical cells do not appear consistent with the psychophysical results. Cells that reach their maximum response at low-to-medium contrasts may account for the contrast independence of psychophysical orientation and spatial frequency discrimination thresholds at medium and high contrasts.

Spatial-Frequency Selectivity in Hemispheric Transfer

2020 ◽  
pp. 319-346
Author(s):  
Frederick L. Kitterle ◽  
Stephen Christman ◽  
Jorge S. Conesa
Keyword(s):  
Spatial Frequency ◽  
Frequency Selectivity

Exposure-Time and Spatial-Frequency Effects in the Tilt Illusion

Perception ◽  
1979 ◽  
Vol 8 (5) ◽  
pp. 557-564 ◽  
Author(s):  
Brian I O'Toole
Keyword(s):  
Spatial Frequency ◽  
Indirect Effects ◽  
Time Course ◽  
Test Line ◽  
Acute Angle ◽  
Direct Effects ◽  
Time Constants ◽  
Frequency Effects ◽  
Tilt Illusion ◽  
Vertical Test

The exposure durations of a vertical test line and a tilted inducing grating were varied and the tilt illusion thus generated was found to change as a function of this variation. Significant direct effects (acute-angle expansion) and indirect effects (acute-angle contraction) were found to occur at times consistent with Andrews's estimate of the time course of inhibition in the visual system when the inducing grating had a spatial frequency of 10 cycles deg−1. However, a 2 · 71 cycles deg−1 grating gave significant effects at exposure durations of 10 as well as 1000 ms, while in a further experiment a 10 · 91 cycles deg−1 grating gave significant effects at 1000 ms only. These results seem to suggest that orientation interactions thought to be due to inhibition (direct effect) and disinhibition (indirect effect) may occur within both sustained and transient channels with concomitant differences in time constants.

A comparison of inhibition in orientation and spatial frequency selectivity of cat visual cortex

Nature ◽  
1986 ◽  
Vol 321 (6067) ◽  
pp. 237-239 ◽  
Author(s):  
A. S. Ramoa ◽  
M. Shadlen ◽  
B. C. Skottun ◽  
R. D. Freeman
Keyword(s):  
Visual Cortex ◽  
Spatial Frequency ◽  
Frequency Selectivity ◽  
Cat Visual Cortex

Spatial-frequency selectivity in contrast detection

1975 ◽  
Vol 15 (6) ◽  
pp. 637-643 ◽  
Author(s):  
R. Frank Quick ◽  
Thomas A. Reichert
Keyword(s):  
Spatial Frequency ◽  
Frequency Selectivity ◽  
Contrast Detection

Orientation and spatial frequency selectivity of adaptation to color and luminance gratings

1988 ◽  
Vol 28 (7) ◽  
pp. 841-856 ◽  
Author(s):  
Arthur Bradley ◽  
Eugene Switkes ◽  
Karen De Valois
Keyword(s):  
Spatial Frequency ◽  
Frequency Selectivity

scholarly journals Differing mechanisms for contrast-dependent spatial frequency selectivity in macaque LGN and V1 neurons

2020 ◽  
Vol 20 (11) ◽  
pp. 1579
Author(s):  
Paul Levy ◽  
Sach Sokol ◽  
Eero P Simoncelli ◽  
J. Anthony Movshon
Keyword(s):  
Spatial Frequency ◽  
Frequency Selectivity ◽  
V1 Neurons
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