Some Observations on the Off-Effect of the Mammalian Cone Electroretinogram

Tansley, Katharine; Copenhaver, Richard M.; Gunkel, Ralph D.

doi:10.1364/josa.51.000207

Cited by 16 publications

(9 citation statements)

References 6 publications

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“…However, the retinae of both Tarentola and Hemidactylus possess sense cells of only one type and yet photopic and scotopic responses in the electroretinogram are very well established in their eyes. This observation is not much different from what Tansley (1957) has found in the pure cone retina of the gray squirrel: " I n dark adaptation and with smaller stimuli the records become more like those usually associated with rods . .…”

Section: Discussioncontrasting

confidence: 57%

“…However,, unlike the findings with the pure cone eyes ot the squirrel and souslik, the presence of scotopic and photopic electroretinograms in the gecko is very definitely connected with what is usually called rod and cone function. While according to Tansley (1957) the light threshold during dark adaptation in the squirrel drops by about 3 log units (the range of adaptation we found in the souslik did not exceed 2 log units), there is in the gecko a change of threshold between light and dark adaptation of more than 6 log units (cf. Fig.…”

Section: Discussionmentioning

confidence: 54%

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The Duplex Nature of the Retina of the Nocturnal Gecko as Reflected in the Electroretinogram

Dodt

Jessen

1961

The Journal of General Physiology

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A b s t r a c t The effect of light and dark adaptation on the electrical activity in two species of nocturnal gecko, Hemidactylus turcicus and Tarentola mauritanica was studied. The electroretinogram of both species changes from the scotopic type in the dark-adapted state to the photopic type after strong light adaptation. For the scotopic response fusion frequencies up to 18 flashes per see. are obtained in both species. For the photopic response fusion frequencies up to 5 ° flashes per see. are seen in Tarentola, and up to 25 flashes per see. in Hemidactylus.Proceeding from dark to light adaptation the increment threshold (dI) is measured at different levels of adaptive illumination (I). At low levels of illumination the dI/I ratio is found to be small and at high levels of illumination to be large. No difference in the dI/I ratio is obtained for test lights of 462 and 605 m#. During dark adaptation the change of threshold after exposure to moderate and weak lights (up to 108 times dark threshold) is rather fast. After light adaptation to strong light (106 times dark threshold) duplex dark adaptation curves are seen with a break separating a fast and a slow phase of dark adaptation. The significance of these results from a retina which possesses sense cells of only one type is discussed.

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Section: Discussioncontrasting

confidence: 57%

Section: Discussionmentioning

confidence: 54%

The Duplex Nature of the Retina of the Nocturnal Gecko as Reflected in the Electroretinogram

Dodt

Jessen

1961

The Journal of General Physiology

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“…The recovery of the b-wave of the corneal ERG after off in a mammalian pure cone retina (squirrel) has also an exponential course, which has been suggested to be due to a decay of the suppression process (Tansley, Copenhaver & Gunkel 1961).…”

mentioning

confidence: 99%

On the Oscillatory Potentials of the Human Electroretinogram in Light and Dark Adaptation

Wachtmeister

1973

Acta Ophthalmologica

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The effect of adaptation to short flashes of light on the oscillatory potentials and the slow potentials (a-and b-wave) of the human ERG as well as the effect on adaptometric visual threshold in response to a series of three flashes were studied. The total energy and the dominant frequency of the oscillatory potentials in response to the third (stimulus) flash were calculated by a combined impulse response and Fourier analysis when the interval between the flashes changed and the intensity of the first two (conditioning) flashes varied. When recorded in response to flashes given at long intervals or conditioning flashes of low intensity the visual threshold recovered to the scotopic branch of the dark adaptation curve and the oscillatory potentials showed a low energy and high frequency (around 150 Hz). On adaptation to flashes at shorter intervals and more intense conditioning flashes [above the threshold for the appearance of the photopic b-wave in response to the second (conditioning) flash], resulting in the recovery of the visual threshold to the photopic branch of the dark adaptation curve, there was an increment of energy and the frequency changed to 105-110 Hz.The slow potentials (a-and b-wave) and the oscillations were differently affected by adaptation to light by previous flashes. The oscillatory potentials showed a 10-fold gain in energy, whereas the amplitudes of the slow potentials were slightly reduced (about 10 Oio). The oscillatory potentials were optimally recorded in the mesopic range

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“…In the grey squirrel e.r.g. temporal summation is almost complete in 20 msec (Tansley, 1957). Even if we use a low estimate ofthe difference, based on the behaviour of human rods and cones, the lack of temporal summation should cause a reduction of the squirrel's visual sensitivity by 0*6 log units, so that the residual discrepancy from man is only about 0 4 log units.…”

Section: Discussionmentioning

confidence: 97%

“…The histology of the squirrel eye, on the other hand, suggests that the entire retina is specialized for acuity, a high degree of adaptation to the animal's arboreal and diurnal mode of life. Arden & Tansley (1955a) and Tansley (1957) found that the e.r.g. threshold in the grey squirrel was high, and that the summation time and dark-adaptation time were short, as would be expected in a pure-cone retina.…”

Section: Visual Thresholds and Spectral Sensitivities Of The Grey Squmentioning

confidence: 99%

Visual thresholds and spectral sensitivities of the grey squirrel (Sciurus carolinensis leucotis)

Arden¹,

Silver²

1962

The Journal of Physiology

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Some Observations on the Off-Effect of the Mammalian Cone Electroretinogram

Cited by 16 publications

References 6 publications

The Duplex Nature of the Retina of the Nocturnal Gecko as Reflected in the Electroretinogram

The Duplex Nature of the Retina of the Nocturnal Gecko as Reflected in the Electroretinogram

On the Oscillatory Potentials of the Human Electroretinogram in Light and Dark Adaptation

Visual thresholds and spectral sensitivities of the grey squirrel (Sciurus carolinensis leucotis)

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