Skip to main content
NCBI home page
The Journal of Physiology logoLink to The Journal of Physiology
. 1979 Jun;291:251–263. doi: 10.1113/jphysiol.1979.sp012810

On the separability of two mechanisms involved in the detection of grating patterns in humans.

I Bodis-Wollner, C D Hendley
PMCID: PMC1280898  PMID: 480212

Abstract

1. The detectability of contrast modulation (M) of sinusoidal gratings was explored at the rate of 8 Hz. The luminance profile of a contrast modulated sinusoidal grating is L = L(1 + C cos 2 pi F chi). This stimulus may also be regarded as the sum of a steady grating pattern and counter phase flicker of the same spatial frequency. 2. Contrast modulation sensitivity (1/M) was established in five observers at several levels of constract and over a range of spatial frequencies, where M = delta C/C of delta C is the just detectable contrast change and C is the mean contrast of the grating. The slope of a modulation sensitivity function (C/delta C vs. C) is 1 (i.e. delta C = constant) near threshold contrast at each spatial frequency, but in the suprathreshold contrast range the slope flattens from close to 1 at 1.5 c/deg to almost 0 (delta C/C = constant) at 12 c/deg. 3. Adaptation to a high contrast steady grating of the same spatial frequency as the contrast modulated test gratings shifts each modulation sensitivity function to the right at low contrasts, but not at high. As a result the adapted curves cross their corresponding unadapted ones. At each spatial frequency the modulation sensitivity function is now fitted by a straight line of slope 1. While delta C needs to be higher than half the detection threshold of the same grating at spatial frequencies above 3 c/deg, in the adapted condition the values are nearly equal at each frequency. Thus pattern adaptation unmasks the threshold of the counterphase component of the contrast modulated grating near threshold contrast as well as above it. The phase of the steady adapting grating, relative to the steady component of the test grating, does not make any difference. 4. Apparently contrast modulation reveals differences beyond threshold sensitivity between spatial frequencies adjacent to the peak of the contrast sensitivity curve. For each spatial frequency channel there must be different neural coupling between steady and modulated inputs. Electrophysiological studies using contrast modulated gratings would be useful in the exploration of individual and ensemble properties of neurones of the visual cortex.

Full text

PDF
251

Selected References

These references are in PubMed. This may not be the complete list of references from this article.

  1. Blakemore C., Campbell F. W. On the existence of neurones in the human visual system selectively sensitive to the orientation and size of retinal images. J Physiol. 1969 Jul;203(1):237–260. doi: 10.1113/jphysiol.1969.sp008862. [DOI] [PMC free article] [PubMed] [Google Scholar]
  2. Blakemore C., Muncey J. P., Ridley R. M. Stimulus specificity in the human visual system. Vision Res. 1973 Oct;13(10):1915–1931. doi: 10.1016/0042-6989(73)90063-1. [DOI] [PubMed] [Google Scholar]
  3. Bodis-Wollner I., Hendley C. D., Kulikowski J. J. Electrophysiological and psychophysical responses to modulation of contrast of a grating pattern. Perception. 1972;1(3):341–349. doi: 10.1068/p010341. [DOI] [PubMed] [Google Scholar]
  4. Breitmeyer B. G., Ganz L. Temporal studies with flashed gratings: inferences about human transient and sustained channels. Vision Res. 1977;17(7):861–865. doi: 10.1016/0042-6989(77)90130-4. [DOI] [PubMed] [Google Scholar]
  5. Campbell F. W., Green D. G. Optical and retinal factors affecting visual resolution. J Physiol. 1965 Dec;181(3):576–593. doi: 10.1113/jphysiol.1965.sp007784. [DOI] [PMC free article] [PubMed] [Google Scholar]
  6. Campbell F. W., Robson J. G. Application of Fourier analysis to the visibility of gratings. J Physiol. 1968 Aug;197(3):551–566. doi: 10.1113/jphysiol.1968.sp008574. [DOI] [PMC free article] [PubMed] [Google Scholar]
  7. Hoffman K. P., Stone J. Conduction velocity of afferents to cat visual cortex: a correlation with cortical receptive field properties. Brain Res. 1971 Sep 24;32(2):460–466. doi: 10.1016/0006-8993(71)90340-4. [DOI] [PubMed] [Google Scholar]
  8. Hubel D. H., Wiesel T. N. Receptive fields and functional architecture of monkey striate cortex. J Physiol. 1968 Mar;195(1):215–243. doi: 10.1113/jphysiol.1968.sp008455. [DOI] [PMC free article] [PubMed] [Google Scholar]
  9. Keesey U. T. Flicker and pattern detection: a comparison of thresholds. J Opt Soc Am. 1972 Mar;62(3):446–448. doi: 10.1364/josa.62.000446. [DOI] [PubMed] [Google Scholar]
  10. King-Smith P. E., Kulikowski J. J. Pattern and flicker detection analysed by subthreshold summation. J Physiol. 1975 Aug;249(3):519–548. doi: 10.1113/jphysiol.1975.sp011028. [DOI] [PMC free article] [PubMed] [Google Scholar]
  11. Kulikowski J. J., Tolhurst D. J. Psychophysical evidence for sustained and transient detectors in human vision. J Physiol. 1973 Jul;232(1):149–162. doi: 10.1113/jphysiol.1973.sp010261. [DOI] [PMC free article] [PubMed] [Google Scholar]
  12. Maffei L., Fiorentini A., Bisti S. Neural correlate of perceptual adaptation to gratings. Science. 1973 Dec 7;182(4116):1036–1038. doi: 10.1126/science.182.4116.1036. [DOI] [PubMed] [Google Scholar]
  13. Maffei L., Fiorentini A. Spatial frequency rows in the straite visual cortex. Vision Res. 1977 Feb;17(2):257–264. doi: 10.1016/0042-6989(77)90089-x. [DOI] [PubMed] [Google Scholar]
  14. Poggio G. F., Doty R. W., Jr, Talbot W. H. Foveal striate cortex of behaving monkey: single-neuron responses to square-wave gratings during fixation of gaze. J Neurophysiol. 1977 Nov;40(6):1369–1391. doi: 10.1152/jn.1977.40.6.1369. [DOI] [PubMed] [Google Scholar]
  15. Schiller P. H., Finlay B. L., Volman S. F. Quantitative studies of single-cell properties in monkey striate cortex. III. Spatial frequency. J Neurophysiol. 1976 Nov;39(6):1334–1351. doi: 10.1152/jn.1976.39.6.1334. [DOI] [PubMed] [Google Scholar]
  16. Watson A. B., Nachmias J. Patterns of temporal interaction in the detection of gratings. Vision Res. 1977;17(8):893–902. doi: 10.1016/0042-6989(77)90063-3. [DOI] [PubMed] [Google Scholar]

Articles from The Journal of Physiology are provided here courtesy of The Physiological Society

RESOURCES