Contrast gain control in the cat visual cortex

Nature ◽  
1982 ◽  
Vol 298 (5871) ◽  
pp. 266-268 ◽  
Author(s):  
I. Ohzawa ◽  
G. Sclar ◽  
R. D. Freeman
Keyword(s):  
Visual Cortex ◽  
Gain Control ◽  
Contrast Gain ◽  
Contrast Gain Control ◽  
Cat Visual Cortex

Contrast and Temporal Frequency-Related Adaptation in the Pretectal Nucleus of the Optic Tract

2005 ◽  
Vol 94 (1) ◽  
pp. 136-146 ◽  
Author(s):  
M. R. Ibbotson
Keyword(s):  
Visual Cortex ◽  
Optic Tract ◽  
Gain Control ◽  
Response Functions ◽  
High Contrast ◽  
Motion Adaptation ◽  
Contrast Gain ◽  
Contrast Gain Control ◽  
Contrast Adaptation ◽  
Contrast Response

In mammals, many cells in the retino-geniculate-cortical pathway adapt during stimulation with high contrast gratings. In the visual cortex, adaptation to high contrast images reduces sensitivity at low contrasts while only moderately affecting sensitivity at high contrasts, thus generating rightward shifts in the contrast response functions (contrast gain control). Similarly, motion adaptation at particular temporal frequencies (TFs) alters the temporal tuning properties of cortical cells. For the first time in any species, this paper investigates the influence of motion adaptation on both the contrast and TF responses of neurons in the retino-pretectal pathway by recording from direction-selective neurons in the nucleus of the optic tract (NOT) of the marsupial wallaby, Macropus eugenii. This species is of interest because its NOT receives almost all input directly from the retina, with virtually none from the visual cortex (unlike cats and primates). All NOT cells show changes in their contrast response functions after adaptation, many revealing contrast gain control. Contrast adaptation is direction-dependent, preferred directions producing the largest changes. The lack of cortical input suggests that contrast adaptation is generated independently from the cortex in the NOT or retina. Motion adaptation also produces direction-selective effects on the TF tuning of NOT neurons by shifting the location of the optimum TF. Cells that show strong adaptation to contrast also tend to show large changes in TF tuning, suggesting similar intracellular mechanisms. The data are discussed in terms of the generality of contrast adaptation across mammalian species and across unconnected brain regions within the same species.

scholarly journals Contrast Gain Control in the Visual Cortex: Monocular Versus Binocular Mechanisms

2000 ◽  
Vol 20 (8) ◽  
pp. 3017-3032 ◽  
Author(s):  
Anthony M. Truchard ◽  
Izumi Ohzawa ◽  
Ralph D. Freeman
Keyword(s):  
Visual Cortex ◽  
Gain Control ◽  
Contrast Gain ◽  
Contrast Gain Control

Contrast Gain Control Is Drift-Rate Dependent: An Informational Analysis

2007 ◽  
Vol 97 (2) ◽  
pp. 1078-1087 ◽  
Author(s):  
M. A. Hietanen ◽  
N. A. Crowder ◽  
M. R. Ibbotson
Keyword(s):  
Visual Cortex ◽  
Fisher Information ◽  
Drift Rate ◽  
Gain Control ◽  
Spike Rate ◽  
Natural Scenes ◽  
Rate Dependency ◽  
Contrast Gain ◽  
Contrast Gain Control ◽  
Rate Dependent

Neurons in the visual cortex code relative changes in illumination (contrast) and adapt their sensitivities to the visual scene by centering the steepest regions of their sigmoidal contrast response functions (CRFs: spike rate as a function of contrast) on the prevailing contrast. The influence of this contrast gain control has not been reported at nonoptimal drift rates. We calculated the Fisher information contained in the CRFs of halothane-anesthetized cats. Fisher information gives a measure of the accuracy of contrast representations based on the ratio of the square of the steepness of the CRF and the spike-rate dependency of the spiking variance. Variance increases with spike rate, so Fisher information is maximal where the CRF is steep and spike rates are low. Here, we show that the contrast at which the maximal Fisher information (CMFI) occurs for each adapting drift rate is at a fixed level above the adapting contrast. For adapting contrasts of 0 to 0.32 the relationship between CMFI and adapting contrast is well described by a straight line with a slope close to 1. The intercept of this line on the CMFI-axis is drift-rate dependent, although the slope is not. At high drift rates relative to each cell's peak the CMFI offset is higher than that for low drift rates. The results show that the contrast coding strategy in visual cortex maximizes accuracy for contrasts above the prevailing contrast in the environment for all drift rates. We argue that tuning the system for accuracy at contrasts above the prevailing value is optimal for viewing natural scenes.

Contrast adaptation and contrast gain control

1991 ◽  
Vol 87 (1) ◽  
Author(s):  
L.M. M��tt�nen ◽  
J.J. Koenderink
Keyword(s):  
Gain Control ◽  
Contrast Gain ◽  
Contrast Gain Control ◽  
Contrast Adaptation

scholarly journals Depth-dependent contrast gain-control

2010 ◽  
Vol 3 (9) ◽  
pp. 49-49
Author(s):  
R. N Aslin ◽  
R. A Jacobs ◽  
P. W Battaglia
Keyword(s):  
Gain Control ◽  
Contrast Gain ◽  
Contrast Gain Control

Callosal regulation of contrast gain control machinery in the human visual system

2013 ◽  
Vol 333 ◽  
pp. e608
Author(s):  
T. Bocci ◽  
M. Caleo ◽  
L. Restani ◽  
L. Briscese ◽  
E. Giorli ◽  
...  
Keyword(s):  
Visual System ◽  
Human Visual System ◽  
Gain Control ◽  
Contrast Gain ◽  
Contrast Gain Control
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