Spatial Frequency Selective Gain Control Pools and Summing Circuits at Oblique Orientations

2010 ◽  
Author(s):  
Anthony R. Williams ◽  
Patrick J. Hibbeler ◽  
Lynn A. Olzak ◽  
Evan J. Barr-Beare
Keyword(s):  
Spatial Frequency ◽  
Gain Control ◽  
Frequency Selective

Spatial frequency selective mechanisms underlying the motion aftereffect

1992 ◽  
Vol 32 (3) ◽  
pp. 561-568 ◽  
Author(s):  
E. Leslie Cameron ◽  
Curtis L. Baker ◽  
Jane C. Boulton
Keyword(s):  
Spatial Frequency ◽  
Motion Aftereffect ◽  
Frequency Selective

Electrophysiological evidence for spatial frequency selective mechanisms in adults and infants

1983 ◽  
Vol 23 (2) ◽  
pp. 119-127 ◽  
Author(s):  
Adriana Fiorentini ◽  
Mario Pirchio ◽  
Donatella Spinelli
Keyword(s):  
Spatial Frequency ◽  
Electrophysiological Evidence ◽  
Frequency Selective

scholarly journals Selective modulation of visual sensitivity during fixation

2018 ◽  
Vol 119 (6) ◽  
pp. 2059-2067 ◽  
Author(s):  
Chris Scholes ◽  
Paul V. McGraw ◽  
Neil W. Roach
Keyword(s):  
Eye Movements ◽  
Spatial Frequency ◽  
Contrast Sensitivity ◽  
Eye Movement ◽  
Visual Processing ◽  
Spatial Scales ◽  
Gain Control ◽  
Visual Sensitivity ◽  
Ocular Movements ◽  
Spatial Frequencies

During periods of steady fixation, we make small-amplitude ocular movements, termed microsaccades, at a rate of 1–2 every second. Early studies provided evidence that visual sensitivity is reduced during microsaccades—akin to the well-established suppression associated with larger saccades. However, the results of more recent work suggest that microsaccades may alter retinal input in a manner that enhances visual sensitivity to some stimuli. Here we parametrically varied the spatial frequency of a stimulus during a detection task and tracked contrast sensitivity as a function of time relative to microsaccades. Our data reveal two distinct modulations of sensitivity: suppression during the eye movement itself and facilitation after the eye has stopped moving. The magnitude of suppression and facilitation of visual sensitivity is related to the spatial content of the stimulus: suppression is greatest for low spatial frequencies, while sensitivity is enhanced most for stimuli of 1–2 cycles/°, spatial frequencies at which we are already most sensitive in the absence of eye movements. We present a model in which the tuning of suppression and facilitation is explained by delayed lateral inhibition between spatial frequency channels. Our data show that eye movements actively modulate visual sensitivity even during fixation: the detectability of images at different spatial scales can be increased or decreased depending on when the image occurs relative to a microsaccade. NEW & NOTEWORTHY Given the frequency with which we make microsaccades during periods of fixation, it is vital that we understand how they affect visual processing. We demonstrate two selective modulations of contrast sensitivity that are time-locked to the occurrence of a microsaccade: suppression of low spatial frequencies during each eye movement and enhancement of higher spatial frequencies after the eye has stopped moving. These complementary changes may arise naturally because of sluggish gain control between spatial channels.

scholarly journals Spatial frequency-selective losses with pattern electroretinogram in Type 1 (insulin-dependent) diabetic patients without retinopathy

Diabetologia ◽  
1990 ◽  
Vol 33 (12) ◽  
pp. 726-730 ◽  
Author(s):  
M. A. S. Di Leo ◽  
B. Falsini ◽  
S. Caputo ◽  
G. Ghirlanda ◽  
V. Porciatti ◽  
...  
Keyword(s):  
Spatial Frequency ◽  
Pattern Electroretinogram ◽  
Diabetic Patients ◽  
Insulin Dependent ◽  
Frequency Selective ◽  
Insulin Dependent Diabetic

scholarly journals Pattern-Sensitive Epilepsy. I: A Demonstration of a Spatial Frequency Selective Epileptic Response to Gratings

Epilepsia ◽  
1980 ◽  
Vol 21 (3) ◽  
pp. 301-312 ◽  
Author(s):  
Michael J. Soso ◽  
Ettore Lettich ◽  
Jack H. Belgum
Keyword(s):  
Spatial Frequency ◽  
Frequency Selective

Spatial properties of envelope-responsive cells in area 17 and 18 neurons of the cat

1996 ◽  
Vol 75 (3) ◽  
pp. 1038-1050 ◽  
Author(s):  
Y. X. Zhou ◽  
C. L. Baker
Keyword(s):  
Receptive Field ◽  
Spatial Frequency ◽  
Direction Selectivity ◽  
Retinal Eccentricity ◽  
Area 17 ◽  
Resolution Limit ◽  
Spatial Properties ◽  
Processing Stream ◽  
Spatial Frequencies ◽  
Frequency Selective

1. Many neurons in areas 17 and 18 respond to spatial contrast envelope stimuli whose Fourier components fall outside the cell's spatial-frequency-selective range. The spatial properties of such envelope responses are investigated here and compared with responses to conventional luminance-defined gratings to explore the underlying receptive-field mechanism. 2. Three spatial properties of envelope responses are reported more extensively in this paper. First, the envelope responses were selective to the carrier spatial frequency in a narrow range of frequencies higher than a given cell's luminance spatial frequency selective range (luminance passband). Second, a given cell's dependence on envelope spatial frequency often differed from its luminance passband. Last, the optimal carrier spatial frequency did not shift systematically with the envelope spatial frequency, supporting the hypothesis that the carrier and envelope spatial-frequency dependencies were mediated by distinct mechanisms. 3. In contrast to the direction selectivity to the envelope motion in many envelope-responsive cells, no direction preference to carrier motion was found for envelope responses. The direction of carrier motion did not alter the direction selectivity for envelope motion, further supporting the hypothesis that the carrier and envelope temporal properties were mediated by separate mechanisms. 4. The distributions of the optimal carrier and luminance spatial frequencies among envelope-responsive cells were analyzed. The optimal carrier spatial frequencies were randomly distributed from five times the cell's optimal luminance spatial frequency to the upper resolution limit of the X-retinal ganglion cells at the same retinal eccentricity, suggesting that the selective ranges of envelope responses and luminance responses are not strongly correlated over the population of envelope-responsive cells. 5. Our data support a "two-stream" receptive-field model for envelope-responsive cells. One stream is a conventional, spatially linear receptive-field mechanism, mediating luminance responses for the cell; the other mediates envelope responses and consists of a two-stage processing: a set of spatially small and distributed nonlinear neural subunits whose outputs are spatially pooled at the second stage. 6. In conclusion, this study indicates that envelope responses in area 17 and 18 neurons cannot be due to a nonlinearity that is common to all visual stimuli before narrowband spatial-frequency-selective filtering; instead, a specialized processing stream, parallel to the conventional luminance response stream, is needed to supplement the traditional luminance processing stream in these cells. This specialized stream responds to the envelope stimuli and is selective to their carrier and envelope spatial frequencies. The distributions of the optimal luminance and carrier spatial frequencies indicate a rich variety of possible integration between luminance and envelope information.

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