Motions of the Retinal Image during Fixation*

Riggs, Lorrin A.; Armington, John C.; Ratliff, Floyd

doi:10.1364/josa.44.000315

Cited by 193 publications

(50 citation statements)

References 13 publications

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“…For such a brief exposure duration, even the largest estimate of 15 set arc reported in previous studies (Ratliff & Riggs, 1950;Barlow, 1952;Ditchbum & Ginsborg, 1953;Riggs, Armington & Ratliff, 1954;Ditchbum, 1955) should not cause appreciable blur in the retinal image for the gratings we used. An eye-movement of 15 set arc would reduce the contrast of a grating of 120c/deg (bar width 15 set) to zero.…”

Section: Apparatus and ~Roce~resmentioning

confidence: 75%

The spread of adaptation in human foveal and parafoveal cone vision

1990

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Abstract-We investigated the spread of bleaching adaptation for human cone vision in the central fovea and at an eccentricity of 5 deg in the nasal retina. Cone thresholds measured after adaptation to a grating bleach were compared to those measured after a uniform bleach. We conclude that the fovea1 and parafoveal cone systems show excellent localization of the etfects of adaptation. For areas 2.5-S min removed from the bleach, our measurement show only small sensitivity losses amounting to between 0.10 and 0.25 log unit elevation in threshold, after taking account of optical scatter. AdaptationCones Fovea Parafovea INTRODUCIIONLight adaptation in the human retina entails a number of different mechanisms (see Hood & Finkelstein, 1986, for a review). The mechanism most commonly identified with adaptation involves the loss of sensitivity, or gain, of retinal cells to incremental stimuli as a consequence of exposure to an adapting light. Although it is generally agreed that the gain changes associated with light adaptation occur early in retinal processing, there is still ambiguity about the anatomical sites of action. In the rod system the primary gain changes do not seem to occur in the receptors themselves (Baylor, Nunn & Schnapf, 1984), but at a site where signals from many rods converge (Rushton & Westheimer, 1962). Rushton (1965) pointed out that the scotopic increment threshold begins to rise at a level where individual rods receive, on the average, less than one quantum per second, suggesting that ~nsitivity is controlled by the pooled signals from many rods. This conclusion is supported by physiological evidence for spatial summation of the effects of adaptation as measured in the rod-driven activity of ganglion cells in the cat (e.g. Cleland & Enroth-Cugell, 1968; Enroth-Cugell & Shapley, 1973). Spatial summation is also observed in the loss of sensitivity associated with very bright bleaching *The expmiments reported here were performed while the authors were at the Uni~~ity of California, San Diego.lights (Rushton $ Westheimer, 1962; Andrews &c Butcher, 1981;Barlow & Andrews, 1973; Bonds & Enroth-Cugell, 1979; MacLeod, Chen & Crognale, 1989;Cicerone & Hayhoe, 1990). It is less clear whether there is a similar kind of spatial summation of adaptation in the cone system. Based on a number of lines of evidence, it has commonly been thought that the primary gain adjustment in response to light occurs in the cone photoreceptors themselves (e.g. Shapley & Enroth-Cugell, 1984). The rr mechanisms isolated by Stiles' chromatic adaptation experiments closely resemble the photopigment spectral sensitivities (Pugh & Sigel, 1978), indicating, to a first approximation, that the different cone types adapt independently and much of adaptation occurs in the cones themselves. More clear cut evidence for receptoral adaptation, at least for bleaching lights, is provided by Wi~ams and MacLeod (1979), who found that bleaching exposures gave inde~ndent sensitivity losses in long-and middle-wavelength-sensitive cone sys...

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Section: Apparatus and ~Roce~resmentioning

confidence: 75%

The spread of adaptation in human foveal and parafoveal cone vision

1990

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“…It was not necessary to control or monitor further the S's eye movements since it has been established that a person can maintain fixation quite easily during the time required for this experiment (Riggs et al, 1954). The E, seated behind the display panel, looked through the small hole and determined that the S was appropriately fixating.…”

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confidence: 99%

Interhemispheric transmission of information: Measurement in normal man

Moscovitch

Catlin

1970

Psychon Sci

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“…The measurement of these small movements during fixation have been reported by several investigators [6,7,8,9,101. The implications of their work and particularly that of Boyce [ l l I were indispensable in our formulating a structure for eye movement control during steady gaze.…”

mentioning

confidence: 85%

“…This leads us to the evaluation of moments relating to random motion inside a local area which can be checked experimentally, subject to the model limitations. and it is easy to see that in view of equation (7) 4 CM(A) I = 0 (9) and…”

Section: B Equation Of Motionmentioning

confidence: 97%