Higher order color mechanisms

Krauskopf, John; Williams, Derric; Mandler, Marc B.; Brown, Angela M.

doi:10.1016/0042-6989(86)90068-4

Cited by 195 publications

(143 citation statements)

References 8 publications

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“…The chromatic preferences of neurons there are broadly distributed throughout the isoluminant plane (Lennie et al, 1990;Wachtler et al, 2003;Johnson et al, 2004;Solomon and Lennie, 2005;Conway and Livingstone, 2006;Horwitz et al, 2007), reminiscent of the higher order color mechanisms inferred psychophysically (Krauskopf et al, 1986;Webster and Mollon, 1994). This suggests that the fundamental mechanisms characterized psychophysically might be established early in V1, at or near the interface with LGN inputs, and that their signals are combined with variable weights before being expressed in the broadly distributed chromatic signatures of most V1 neurons.…”

Section: Introductionmentioning

confidence: 94%

“…Chromatic preferences are broadly distributed among cortical neurons, so over the population as a whole response adaptation will cause the greatest loss of sensitivity in neurons tuned to the direction of the habituating modulation. This is of considerable interest in the context of psychophysical observations (Krauskopf et al, 1982(Krauskopf et al, , 1986Webster and Mollon, 1994) that reveal, in addition to the cardinal mechanisms, innumerable less prominent mechanisms tuned along different directions in color space. These characteristics of what have been called "higher order" mechanisms (Krauskopf et al, 1986) are consistent with their arising in response adaptation in neurons that receive input from the fundamental mechanisms.…”

Section: Relationship To Psychophysicsmentioning

confidence: 99%

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Habituation Reveals Fundamental Chromatic Mechanisms in Striate Cortex of Macaque

Tailby¹,

Solomon²,

Dhruv³

et al. 2008

J. Neurosci.

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Prolonged viewing of a chromatically modulated stimulus usually leads to changes in its appearance, and that of similar stimuli. These aftereffects of habituation have been thought to reflect the activity of two populations of neurons in visual cortex that have particular importance in color vision, one sensitive to red-green modulation, the other to blue-yellow, but they have not been identified. We show here, in recordings from macaque primary visual cortex (V1), that prolonged exposure to chromatic modulation reveals two fundamental mechanisms with distinctive chromatic signatures that match those of the mechanisms identified by perceptual observations. In nearly all neurons, these mechanisms contribute to both excitation and to regulatory gain controls, and as a result their habituation can have paradoxical effects on response. The mechanisms must be located near the input layers of V1, before their distinct chromatic signatures diffuse. Our observations suggest that the fundamental mechanisms do not give rise to two distinct L-M and S chromatic pathways. Rather, the mechanisms are better understood as stages in the elaboration of chromatic tuning, expressed in varying proportions in all cells in V1 (and beyond), and made accessible to physiological and perceptual investigation only through habituation.

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Section: Introductionmentioning

confidence: 94%

Section: Relationship To Psychophysicsmentioning

confidence: 99%

Habituation Reveals Fundamental Chromatic Mechanisms in Striate Cortex of Macaque

Tailby¹,

Solomon²,

Dhruv³

et al. 2008

J. Neurosci.

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“…1 provides a convenient vehicle for expressing the chromatic characteristics of cells in ways that can be compared with the properties of second-stage mechanisms of color vision identified psychophysically (Krauskopf et al, 1982(Krauskopf et al, , 1986Webster & Mollon, 1991), but it is a less useful vehicle for expressing the strengths of inputs a cell receives from individual classes of cones. For this reason, we also represent the properties of cells by the weights they attach to signals from the different classes of cones.…”

Section: Visual Stimulimentioning

confidence: 99%

Distinctive characteristics of subclasses of red–green P-cells in LGN of macaque

1998

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We characterized the chromatic and temporal properties of a sample of 177 red-green parvocellular neurons in the LGN of Macaca nemestrina, using large-field stimuli modulated along different directions through a white point in color space. We examined differences among the properties of the four subclasses of red-green P-cells (on-and off-center, red and green center). The responses of off-center cells lag the stimulus more than do those of on-center cells. At low temporal frequencies, this causes the phase difference between responses of the two kinds of cells to be considerably less than 180 deg. For isoluminant modulations the phases of on-and off-responses were more nearly 180 deg apart. A cell's temporal characteristics did not depend on the class of cone driving its center. Red center and green center cells have characteristically different chromatic properties, expressed either as preferred elevations in color space, or as weights with which cells combine inputs from L-and M-cones. Red center cells are relatively more responsive to achromatic modulation, and attach relatively more weight to input from the cones driving the center. Off-center cells also attach relatively more weight than do on-center cells to input from the class of cone driving the center.

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“…To provide an explicit link between psychophysical chromatic mechanisms and color physiology and to address the controversy regarding the number and nature of chromatic mechanisms (Eskew, 2009), we conducted two sets of psychophysical experiments in monkeys. In one set of experiments, we measured color-detection thresholds after FF chromatic adaptation similar to Krauskopf et al (1982Krauskopf et al ( , 1986. Such stimuli would theoretically affect color-coding mechanisms that are not tuned for spatial structure, such as subcortical cone-opponent signals.…”

Section: Introductionmentioning

confidence: 99%

“…Other experiments have implicated more than two "higher-order" mechanisms each tuned to a different direction in color space. The first such evidence, by Krauskopf et al (1986), depended on a Fourier analysis of data originally used to endorse the cardinalmechanism model. Additional evidence, using a range of paradigms, followed (Boynton et al, 1986;Krauskopf et al, 1986;Flanagan et al, 1990;D'Zmura, 1991;Gegenfurtner and Kiper, 1992;Krauskopf and Gegenfurtner, 1992;Sachtler and Zaidi, 1992;Zaidi and Halevy, 1993;Webster and Mollon, 1994;D'Zmura and Knoblauch, 1998;Hansen and Gegenfurtner, 2006).…”

Section: Introductionmentioning

confidence: 99%

Psychophysical Chromatic Mechanisms in Macaque Monkey

et al. 2012

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Chromatic mechanisms have been studied extensively with psychophysical techniques in humans, but the number and nature of the mechanisms are still controversial. Appeals to monkey neurophysiology are often used to sort out the competing claims and to test hypotheses arising from the experiments in humans, but psychophysical chromatic mechanisms have never been assessed in monkeys. Here we address this issue by measuring color-detection thresholds in monkeys before and after chromatic adaptation, employing a standard approach used to determine chromatic mechanisms in humans. We conducted separate experiments using adaptation configured as either flickering full-field colors or heterochromatic gratings. Full-field colors would favor activity within the visual system at or before the arrival of retinal signals to V1, before the spatialtransformationofcolorsignalsbythecortex.Conversely,gratingswouldfavoractivitywithinthecortexwhereneuronsareoftensensitive tospatialchromaticstructure.Detectionthresholdswereselectivelyelevatedforthecolorsoffull-fieldadaptationwhenitmodulatedalongeither of the two cardinal chromatic axes that define cone-opponent color space [L vs M or S vs (L ϩ M)], providing evidence for two privileged cardinal chromatic mechanisms implemented early in the visual-processing hierarchy. Adaptation with gratings produced elevated thresholds for colors of the adaptation regardless of its chromatic makeup, suggesting a cortical representation comprised of multiple higher-order mechanisms each selective for a different direction in color space. The results suggest that color is represented by two cardinal channels early in the processing hierarchy and many chromatic channels in brain regions closer to perceptual readout.

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Higher order color mechanisms

Cited by 195 publications

References 8 publications

Habituation Reveals Fundamental Chromatic Mechanisms in Striate Cortex of Macaque

Habituation Reveals Fundamental Chromatic Mechanisms in Striate Cortex of Macaque

Distinctive characteristics of subclasses of red–green P-cells in LGN of macaque

Psychophysical Chromatic Mechanisms in Macaque Monkey

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