Dark and Light Adaptation in Pigmented and White Rat as Measured by Electroretinogram Threshold

Dodt, E.; Echte, K.

doi:10.1152/jn.1961.24.4.427

Cited by 159 publications

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“…6A shows that the latency of the b-wave for a given stimulus is almost unchanged during photochemical dark adaptation even if the threshold of the b-wave changes by 3 log units, and even if the amplitude for any given intensity falls by more than a factor of 10. The family of amplitude curves obtained here is similar to the families obtained by previous investigators (1,3,4). However, a new characteristic of the b-wave amplitude is brought out by the present recording conditions and the method used for measuring the bwave amplitude.…”

Section: E F F E C T S Of a D A P T A T I O Nsupporting

confidence: 86%

“…A p p a r e n t l y the plateau forms because both P I I and P I I I increase with intensity at the same rate w h e n the intensity is greater t h a n a b o u t 20 q u a n t a / rod. T o partially d e t e r m i n e the extent of the small contribution of a red-sensitive (possibly cone) system which has been detected in the rat by previous investigators (4,6), all the following experiments were carried out using b o t h 1 = 7 0 q u a n t a / r o d green 0 ,~z a b o u t 500 mtz) and white light. N o significant differences were noted.…”

Section: Xo95mentioning

confidence: 99%

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The Rat Electroretinogram

Cone

1964

The Journal of General Physiology

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Characteristics of the electroretinogram (ERG) produced by the essentially all rod eye of the rat are presented as functions of the number of quanta absorbed by each rod per stimulus flash. The ERG's were obtained with 1.5 msec. stimulus flashes and uniform illumination of the entire retina. Under these conditions, distortions in the ERG due to stray light are minimized, and the ERG more accurately reflects the activity of its retinal sources. The effects of background light and two forms of dark adaptation were studied and compared. The results, especially for the b-wave, permit an interpretation in terms of two distinct processes. One process appears to determine the b-wave latency. This process is almost independent of the state of adaptation of the retina. The other process does not affect the latency, but determines the b-wave threshold and amplitude. This process strongly depends upon the state of adaptation. Moreover, the effects of dark adaptation on this amplitude-determining process are almost identical with the effects of background light.

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Section: E F F E C T S Of a D A P T A T I O Nsupporting

confidence: 86%

Section: Xo95mentioning

confidence: 99%

The Rat Electroretinogram

Cone

1964

The Journal of General Physiology

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“…The threshold for visual responses in the rat is also much lower than that for phase shifts in the hamster. The minimum threshold for the bwave of the ERG is approximately 2 x 10' cd m-2 after 12 h of dark adaptation (4 x 10' td; Dodt & Echte, 1961). A similar threshold has been measured behaviourally (Silver, 1967) and evidence suggests that the limits of luminance detectability may also be controlled by a circadian rhythm in the rat (Rosenwasser, Raibert, Terman & Terman, 1979).…”

Section: Sensitivity To Stimulus Irradiancesupporting

confidence: 57%

Sensitivity and integration in a visual pathway for circadian entrainment in the hamster (Mesocricetus auratus).

Nelson

Takahashi

1991

The Journal of Physiology

293

173

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SUMMARY1. Light-induced phase shifts of the circadian rhythm of wheel-running activity were used to measure the photic sensitivity of a circadian pacemaker and the visual pathway that conveys light information to it in the golden hamster (Mesocricetus auratus). The sensitivity to stimulus irradiance and duration was assessed by measuring the magnitude of phase-shift responses to photic stimuli of different irradiance and duration. The visual sensitivity was also measured at three different phases of the circadian rhythm.2. The stimulus-response curves measured at different circadian phases suggest that the maximum phase-shift is the only aspect of visual responsivity to change as a function of the circadian day. The half-saturation constants (G.) for the stimulus-response curves are not significantly different over the three circadian phases tested. The photic sensitivity to irradiance (1/ao) appears to remain constant over the circadian day.3. The hamster circadian pacemaker and the photoreceptive system that subserves it are more sensitive to the irradiance of longer-duration stimuli than to irradiance of briefer stimuli. The system is maximally sensitive to the irradiance of stimuli of 300 s and longer in duration. A quantitative model is presented to explain the changes that occur in the stimulus-response curves as a function of photic stimulus duration.4. The threshold for photic stimulation of the hamster circadian pacemaker is also quite high. The threshold irradiance (the minimum irradiance necessary to induce statistically significant responses) is approximately 1011 photons cm-2 s-5 for optimal stimulus durations. This threshold is equivalent to a luminance at the cornea of 0-1 cdm2.5. We also measured the sensitivity of this visual pathway to the total number of photons in a stimulus. This system is maximally sensitive to photons in stimuli between 30 and 3600 s in duration. The maximum quantum efficiency of photic integration occurs in 300 s stimuli.6. These results suggest that the visual pathways that convey light information to t Present address:

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“…This has not been observed in e.r.g. measurements even at background intensities that bleach the rhodopsin almost completely (Dodt & Echte, 1961;Dowling, 1963). In view of our finding that the saturation effect can be explained by an accumulation of metarhodopsin in the rods, an effect that does not show any lateral spread in the retina, it is likely that the e.r.g.…”

Section: Resultsmentioning

confidence: 68%

Visual adaptation of the rhodopsin rods in the frog's retina

Donner¹,

Reuter²

1968

The Journal of Physiology

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2. When such thresholds and the intensities of the background lights are expressed in terms of the number of quanta absorbed per unit time, it is found that three factors can be correlated with the thresholds measured in various states of light-and dark-adaptation: (i) the intensity of a steady background, (ii) the rate of regeneration of rhodopsin, and (iii) the amount of metarhodopsin II present in the rods.3. The threshold is found to be proportional both to the intensity of a background and to the rate of regeneration, whereas there is a linear relationship between the logarithm of the threshold and the amount of metarhodopsin II. 4. The presence of metarhodopsin elevates all thresholds, the absolute threshold, increment thresholds and the thresholds elevated by regenerating rhodopsin in the same way.5. The saturation of the rods at high background intensities is found to be correlated with the accumulation of significant amounts of metarhodopsin in the rods, caused by the bleaching effect of the background.6. The effect of metarhodopsin on the threshold is independent of the amount of rhodopsin present in the rods.7. The combined effect of all three factors can be expressed in a general formula, given as eqn. (7) on p. 74.8. A background not only reduces the signals from the rods illuminated, but also those from neighbouring unilluminated rods. This effect is rapidly decreased with increasing distance from rods covered by the background. This kind of lateral spread in the retina probably occurs also when the K. 0. DONNER AND TOM REUTER rate of regeneration affects the threshold. The effect of metarhodopsin, on the other hand, appears restricted to those receptors that contain this substance.

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Dark and Light Adaptation in Pigmented and White Rat as Measured by Electroretinogram Threshold

Cited by 159 publications

References 0 publications

The Rat Electroretinogram

The Rat Electroretinogram

Sensitivity and integration in a visual pathway for circadian entrainment in the hamster (Mesocricetus auratus).

Visual adaptation of the rhodopsin rods in the frog's retina

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