Heterochromatic modulation photometry

Pokorny, Joel; Smith, Vivianne C.; Lutze, Margaret

doi:10.1364/josaa.6.001618

Cited by 50 publications

(26 citation statements)

References 14 publications

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“…Calculation of chromaticity values was based on Smith–Pokorny 2° cone fundamentals (Smith & Pokorny, 1975). An equiluminant level of each of the three CRT phosphors was measured for every observer using heterochromatic modulation photometry at 15 Hz (Pokorny, Smith, & Lutz, 1989). …”

Section: Methodsmentioning

confidence: 99%

Interocular suppression differentially affects achromatic and chromatic mechanisms

Hong

Blake

2009

Attention, Perception & Psychophysics

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Section: Methodsmentioning

confidence: 99%

Interocular suppression differentially affects achromatic and chromatic mechanisms

Hong

Blake

2009

Attention, Perception & Psychophysics

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“…At each step, a number of modulation depths were tested and response amplitudes were fitted with a Naka-Rushton function 22 to estimate cell responsivity. Cell responsivity at the different steps was fitted with a template 23 to estimate the luminance ratio with lowest responsivity. Four conditions were tested: 2,000 td 605 nm; 2,000 td 570 nm; 200 td 605 nm; 200 td 570 nm.…”

Section: Methodsmentioning

confidence: 99%

Temporal sensitivity of macaque ganglion cells to lights of different chromaticity

Pokorny¹,

Smith²,

Lee³

et al. 2000

Color Res. Appl.

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Three psychophysical paradigms have shown that moderately high retinal illuminance (ca. 1000 td) longwavelength chromatic adaptation results in a disproportionate reduction in visual sensitivity to rapidly modulated lights. (i) Critical-flicker-fusion -log retinal illuminance (CFF-log I) functions are shallower for long-wavelength than middle-wavelength modulated lights. (ii) A long-wavelength light modulated just above CFF appears as flickering if a steady middle-wavelength pedestal is added. (iii) The R/G ratio for heterochromatic modulation photometric (HMP) equality increases with light level when the mean chromaticity is Ϸ605 nm, but not when it is Ϸ570 nm. The goal was to evaluate whether Magnocellular-(MC-) pathway retinal ganglion cells show reduced modulation sensitivity with long-wavelength adaptation, as is observed with these three psychophysical paradigms. In Experiment (1), CFFs for 554 and 638 nm lights were estimated by noting the temporal frequencies at which the cells firing fell below 10 imp/s. CFF was measured for light levels between 1-1000 td. Seventeen of 17 units showed a higher CFF at 1000 td for 554 nm, consistent with psychophysical observation. In Experiment (2), a steady 1000 td 554 nm pedestal was added to a 1000 td 638 nm modulated light. Four of 6 units showed higher 638 nm CFF when the steady 554 nm pedestal was present. In Experiment (3), Heterochromatic Modulation Photometry responsivities were obtained at 200 and 2000 td as a function of the relative modulation of 554 and 638 nm counterphase lights. Chromaticity was metameric to either 605 or 570 nm. Fifteen of 17 units showed substantial changes in log (R/G) with luminance for the 605 nm, but not for the 570 nm adaptation condition. Thus, temporal phenomena observed psychophysically may be seen in MC-pathway cells. The results are interpretable as arising from interactions between signals originating from the L-and M-cone receptor types, not from differences in temporal properties of the two-cone types.

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“…Bowker, 1983; Kelly, 1975; Lee, Pokorny, Smith,Martin, & Valberg, 1990; Pokorny, Smith, & Lutze, 1989), but comparatively little research examines how the properties of temporally varying surrounding light affect perceived temporal variation induced within a steady uniform region (De Valois et al, 1986; Kinney, 1965, 1967; Rossi & Paradiso, 1996). A consistent finding in earlier work is that the perceived modulation depth induced within a central region is severely attenuated at temporal inducing frequencies above about 3 Hz (D’Antona & Shevell, 2006; De Valois et al, 1986; Rossi & Paradiso, 1996).…”

Section: Introductionmentioning

confidence: 99%

Induced temporal variation at frequencies not in the stimulus: Evidence for a neural nonlinearity

D’Antona

Shevell

2009

Journal of Vision

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The perceived color of a light depends on surrounding light. When the surround varies slowly over time, a central, physically steady light is perceived to vary also. This perceived temporal variation of the central region, however, is strongly attenuated when the surround varies faster than ~3 Hz (R. L. De Valois, M. A. Webster, K. K. De Valois, & B. Lingelbach, 1986). The classical explanation is low-pass temporal filtering at a cortical stage that attenuates the neural representation of temporal frequencies capable of causing induced temporal variation. This theory assumes neural responses are linear, so only temporal frequencies in the stimulus are represented in the neural response. The current experiments revealed that temporal frequencies above 3 Hz are capable of inducing temporal variation. Specifically, with two temporal frequencies superimposed in the surround, the induced temporal variation in the uniform region is at the difference frequency of these two frequencies, even though this frequency is not physically present in the stimulus. The results are accounted for by a nonlinear neural process, which causes temporal variation at the difference frequency, and a following linear temporal filter.

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Heterochromatic modulation photometry

Cited by 50 publications

References 14 publications

Interocular suppression differentially affects achromatic and chromatic mechanisms

Interocular suppression differentially affects achromatic and chromatic mechanisms

Temporal sensitivity of macaque ganglion cells to lights of different chromaticity

Induced temporal variation at frequencies not in the stimulus: Evidence for a neural nonlinearity

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