Does L/M Cone Opponency Disappear in Human Periphery?

Perception ◽  
10.1068/p5374 ◽  
2005 ◽  
Vol 34 (8) ◽  
pp. 951-959 ◽  
Author(s):  
Kathy T Mullen ◽  
Masato Sakurai ◽  
William Chu
Keyword(s):  
Spatial Frequency ◽  
Contrast Sensitivity ◽  
Sine Wave ◽  
Human Vision ◽  
Peripheral Retina ◽  
Contrast Detection ◽  
Colour Contrast

We have assessed the optimal cone contrast sensitivity across eccentricity in human vision of the two cone-opponent mechanisms [L/M or red-green, and S/(L + M) or blue-yellow] and the luminance mechanism. We have used a novel stimulus, termed a ‘sinring’, that is a radially modulated sine-wave arc, Gaussian enveloped in both angular and radial directions. This stimulus overcomes the problem inherent in Gabor stimuli of confounding stimulus spatial frequency, size, and eccentricity and so allows contrast sensitivity to be tracked accurately into the periphery. Our results show that L/M cone opponency declines steeply across the human periphery and becomes behaviourally absent by 25–30 deg (in the nasal field). This result suggests that any L/M cone-opponent neurons found in primate peripheral retina beyond this limit are unlikely to be significant for colour contrast detection measured behaviourally.

Contrast Sensitivity of Air-Breathing Nonprofessional Scuba Divers at a Depth of 40 Meters

1992 ◽  
Vol 75 (1) ◽  
pp. 275-283
Author(s):  
Nico A. M. Schellart
Keyword(s):  
Spatial Frequency ◽  
Contrast Sensitivity ◽  
Fresh Water ◽  
Test Pattern ◽  
Sine Wave ◽  
Air Breathing ◽  
Scuba Divers ◽  
Visual Contrast ◽  
Sine Wave Gratings ◽  
Visual Contrast Sensitivity

Photopic contrast sensitivity of air-breathing scuba divers was measured with a translucent test pattern at depths up to 40 m. The pattern was composed of sine wave gratings with spatial frequency and contrast changing logarithmically. The spatial transfer characteristics were measured at various depths under controlled optical conditions in seawater and in fresh water. Analysis indicates that the visual contrast sensitivity, and therefore probably also acuity, of sport divers is not affected up to depths of 40 m. This holds under ideal as well as poor diving conditions.

scholarly journals Is the DeVries-Rose to Weber Transition Empirically Possible with Sine-Wave Gratings?

2005 ◽  
Vol 8 (2) ◽  
pp. 113-118
Author(s):  
Miguel A. García-Pérez
Keyword(s):  
Spatial Frequency ◽  
Contrast Sensitivity ◽  
Light Level ◽  
Sine Wave ◽  
Retinal Illuminance ◽  
Visual Functioning ◽  
Photopic Vision ◽  
Spatial Frequencies ◽  
Grating Acuity ◽  
Sine Wave Gratings

Visual functioning at various retinal illuminance levels is usually measured either by determining grating acuity as a function of light level or by determining how sensitivity to sine-wave gratings changes with retinal illuminance. The former line of research has shown that grating acuity follows a two-branch relationship with retinal illuminance, with the point of discontinuity occurring at the transition from scotopic to photopic vision. Results of the latter line of research have summarily been described as a transition from the DeVries-Rose law to Weber's law, according to which log sensitivity increases linearly with log illuminance with a slope of 0.5 over a range of low illuminances (the DeVries-Rose range) and then levels off and does not increase with further increases of illuminance (the Weber range). This paper aims at determining the compatibility of the results of these two lines of research. We consider empirical constraints from data bearing on the shape of the surface describing contrast sensitivity to sine-wave gratings as a function of spatial frequency and illuminance simultaneously, in order to determine whether they are consistent with a summary description in terms of DeVries-Rose and Weber's laws. Our analysis indicates that, with sine-wave gratings, the DeVries-Rose law can only hold empirically at low spatial frequencies.

Monophasic Temporal Modulation Increases Apparent Spatial Frequency

Perception ◽  
1974 ◽  
Vol 3 (3) ◽  
pp. 337-353 ◽  
Author(s):  
V Virsu ◽  
G Nyman
Keyword(s):  
Spatial Frequency ◽  
Contrast Sensitivity ◽  
Spatial Effect ◽  
Phase Changes ◽  
Human Vision ◽  
Maximum Effect ◽  
Temporal Modulation ◽  
Flicker Fusion Frequency ◽  
Spatial Phase ◽  
Spatial Frequencies

There are three different types of flicker—monophasic, diphasic, and polyphasic—and they have different spatial consequences with gratings. Monophasic flicker does not alter the spatial phase in time, but spatial phase changes are caused by the other two types. The effects of sinusoidal monophasic flicker on the apparent spatial frequency of sinusoidal gratings were studied in the present experiments by simultaneous spatial-frequency matches. Monophasic temporal modulation increased apparent spatial frequency. The stimulus conditions for producing a maximum effect were (a) a relatively low spatial frequency, (b) a relatively high level of light adaptation, (c) an intermediate temporal frequency (4–8 Hz), and (d) an intermediate contrast. The largest apparent increases exceeded 30%. The magnitude of the spatial effect was correlated with data on temporal resolution and contrast sensitivity collected under the same conditions. The spatial effect had a high correlation with the critical flicker-fusion frequency, and the contrast-sensitivity enhancements caused by the flicker followed functions similar to those of the spatial effect when the spatial frequency and the level of adaptation were varied. We interpret the spatial effect of low-frequency monophasic flicker as evidence that there are channels for spatial frequency in human vision whose spatial tuning depends on the spatial distribution of sensitivity in the receptive fields of single neurones. Flicker at intermediate temporal frequencies decreases the functional effectiveness of centre—surround antagonism, and makes channels otherwise responsive to high spatial frequencies responsive to low spatial frequencies. As the central decoding of channel outputs can be assumed invariant, an increase in the apparent spatial frequency follows from the change of tuning properties if the channels mediate the perception of spatial frequency. An analysis of the variability of spatial frequency matches indicated that spatial frequency discrimination, if considered in relative terms, is independent of the spatial frequency, the mean luminance, and the contrast of gratings within broad ranges of variation.

scholarly journals Macular colour contrast sensitivity in ocular hypertension and glaucoma: evidence for two types of defect.

1991 ◽  
Vol 75 (10) ◽  
pp. 598-602 ◽  
Author(s):  
F. M. Falcao-Reis ◽  
F. O'Sullivan ◽  
W. Spileers ◽  
C. Hogg ◽  
G. B. Arden
Keyword(s):  
Ocular Hypertension ◽  
Contrast Sensitivity ◽  
Colour Contrast

Adapted and unadapted spatial frequency channels in human vision

1973 ◽  
Vol 13 (11) ◽  
pp. 2139-2143 ◽  
Author(s):  
Robert V. Lange ◽  
Claude Sige ◽  
Sidney Stecher
Keyword(s):  
Spatial Frequency ◽  
Human Vision

scholarly journals A study of sine-wave contrast sensitivity by two psychophysical methods

1973 ◽  
Vol 14 (2) ◽  
pp. 313-318 ◽  
Author(s):  
D. H. Kelly ◽  
R. E. Savoie
Keyword(s):  
Contrast Sensitivity ◽  
Sine Wave

VEP and PERG acuity in anesthetized young adult rhesus monkeys

1999 ◽  
Vol 16 (4) ◽  
pp. 607-617 ◽  
Author(s):  
JAMES N. VER HOEVE ◽  
YURI P. DANILOV ◽  
CHARLENE B.Y. KIM ◽  
PETER D. SPEAR
Keyword(s):  
Young Adult ◽  
Spatial Frequency ◽  
Rhesus Monkeys ◽  
Dose Range ◽  
High Spatial Frequency ◽  
Sine Wave ◽  
Frequency Method ◽  
Behavioral Studies ◽  
S Period ◽  
Highly Correlated

This study used the swept spatial-frequency method to compare retinal and cortical acuity in anesthetized young adult rhesus monkeys. Visual evoked potentials (VEPs) and pattern electroretinographic responses (PERGs) were recorded from 25 monkeys (age range: 4–12 years) anesthetized with a continuous infusion of propofol. The stimuli were temporally countermodulated sine-wave gratings that increased in spatial frequency within a 10.24-s period. All animals were refracted using acuity estimated from the zero micro-volt intercept of the linear regression of evoked potential amplitude on spatial frequency. Average sweep acuities were 23.7 cycles/deg ± 1.5 S.E.M. and 23.1 cycles/deg ± 1.8 S.E.M. for the PERG and VEP, respectively. VEP and PERG acuities were within the range expected based on acuities estimated from behavioral studies in macaques. PERG and VEP acuities were highly correlated (r = 0.90) and equally sensitive to spherical blur. On a subset of animals, test–retest reliability of animals, and interocular correlations, were high (r = 0.87 and r = 0.83, respectively). Increasing propofol dosage 8-fold did not degrade PERG or VEP acuity. This study demonstrates that high spatial-frequency acuities can be rapidly obtained from young adult rhesus monkeys under a wide dose range of propofol anesthesia using the swept spatial-frequency method.

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