Light adaptation and responses to contrast flashes in cones of the walleye retina

Burkhardt, Dwight A.; Gottesman, Jon

doi:10.1016/0042-6989(87)90151-9

Cited by 21 publications

(40 citation statements)

References 22 publications

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“…The intensity range fallen exclusively within the rod range (Field GD and Rieke F, 2002; Völgyi et al, 2004). The contrast of the stimuli was calculated by using the Michelson Contrast Equation: Contrast = (F-B)/(F+B) (Burkhardt and Gottesman, 1987), where F is the light intensity of the spots of light, and B is the steady background intensity. In the current study, under scotopic conditions, the steady background intensity was 0, thus, the contrast was 1.…”

Section: Methodsmentioning

confidence: 99%

Mechanisms that limit the light stimulus frequency following through the dl-2-amino-4-phosphonobutyric acid sensitive and insensitive rod Off-pathways

et al. 2009

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In the retina, rod signal pathways process scotopic visual information. Light decrements are mediated by two distinct groups of rod pathways in the dark adapted retina that can be differentiated on the basis of their sensitivity to the glutamate agonist DL-2-amino-4-phosphonobutyric acid (APB). We have found that the APB sensitive and insensitive rod Off-pathways signal different light decrement information: the APB sensitive rod Off-pathway conveys slow and low frequency light signals, whereas the APB insensitive rod Off-pathways mediate fast and high frequency light signals (Wang, 2006). However, the mechanisms which limit the frequency following through the APB sensitive and insensitive rod Off-pathways remain unknown. In the current study, whole-cell patch-clamp recordings were made from ganglion cells in dark and light adapted mouse retina to identify the mechanisms that limit the frequency following through the APB sensitive and insensitive rod Offpathways. The results showed that the sites from AII amacrine cells to Off cone bipolar cells are the major mechanisms that limit the frequency following through the APB sensitive rod Off-pathway. In the APB insensitive rod Off-pathways, rods themselves limited the frequency following through these pathways. Moreover, ganglion cells were able to follow higher frequencies under photopic conditions than under scotopic conditions. The Off responses followed lower frequencies than On responses under photopic conditions. This finding was observed in cells that yielded On or Off responses only as well as in On-Off cells. Keywordsretinal ganglion cell; scotopic condition; photopic condition; APB; rod pathways; cone pathways Distinct signaling pathways within the retina code for different types of visual information. The cone pathways mediate coding of visual information for photopic vision at relatively high light intensities. By contrast, the rod pathways underlie the coding for scotopic vision at relatively low light intensities (reviewed by: Dowling, 1987;Sterling and Demb, 2004). Light

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Section: Methodsmentioning

confidence: 99%

Mechanisms that limit the light stimulus frequency following through the dl-2-amino-4-phosphonobutyric acid sensitive and insensitive rod Off-pathways

et al. 2009

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“…The response of retinal neurons will then largely depend on the contrast between an object and its background, rather than the absolute light intensity of the object. Approximations toward such invariance, or contrast constancy, have been observed under various conditions in retinal neurons and human psychophysics over the years (e.g., Shapley and Enroth-Cugell, 1984;Burkhardt and Gottesman, 1987;Walraven et al, 1990;Whittle, 1993). Although there is much evidence for Weber's law behavior in vertebrate vision, the retinal mechanisms for this and other aspects of light adaptation are still not fully understood.…”

Section: Light Adaptationmentioning

confidence: 99%

Light adaptation and photopigment bleaching in cone photoreceptors in situ in the retina of the turtle

1994

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Light adaptation and photopigment bleaching in cone photoreceptors were studied in the intact, superfused retina of the turtle (Pseudemys scripta elegans). A new method for measuring changes in the photopigment of cones is described. Action spectrum measurements indicate that the signals arise from the red-sensitive cones. Measurements of steady-state bleaching are well described by the monomolecular bleaching equation with a half-bleaching constant of about 5.5 log photons sec-1 microns-2. Quantitative data on light adaptation were obtained by intracellular recording from 15 red- sensitive cones over nearly 8 decades of background illumination obtained from a helium-neon laser (632.8 nm). The steady-state membrane potential, Rs, and the rate of photoisomerization of the photopigment, Pi, rose in parallel with background illumination and then stabilized over the upper 4 decades of illumination. These results are described by the relation Rs = k Pi0.27, and suggest that about 5 x 10(6) photoisomerizations sec-1 lead to the closure of half the cone's light- sensitive channels in the steady state. A full range of decremental and incremental flashes was used to investigate stimulus-response relations. Cones tended to generate responses of approximately constant amplitude to flashes of constant contrast over a substantial range of contrast (< or = 3 x) and background illumination (approximately 3–4 decades). This suggests that a substantial component of contrast constancy in vertebrate vision may originate in cones. Over nearly 7 decades, the small-signal step sensitivity was found to conform closely to Weber's law (sensitivity is inversely proportional to background illumination). Thus, Weber's law extends into the ultra-high-intensity realm, some 3 decades higher than previously known for vertebrate cones. Over the upper 3–4 decades of illumination, Weber's law behavior can be explained by the depletion of photopigment (reduced probability of the photon catch). There remains a substantial low-intensity domain for which light adaptation and Weber's law behavior are presumably mediated by other mechanisms within the cone. These might be the calcium- and/or cGMP-dependent mechanisms recently suggested by others.

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“…The contrast of the stimuli was calculated by using the Michelson contrast equation: contrast=(F−B)/(F+B), where F is the light intensity of the spots of light, and B is the steady background intensity (Burkhardt & Gottesman, 1987). The lowest intensity required to evoke optimal responses was used to stimulate the retinas and to test the effects of L-NAME on the light-evoked On and Off excitatory and inhibitory pathways.…”

Section: Methodsmentioning

confidence: 99%

Inhibition of nitric oxide synthase desensitizes retinal ganglion cells to light by diminishing their excitatory synaptic currents under light adaptation

Nemargut

Wang

2009

Vision Research

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The effect of inhibiting nitric oxide synthase (NOS) on the visual responses of mouse retinal ganglion cells (RGCs) was studied under light adaptation by using patch-clamp recordings. The results demonstrated that NOS inhibitor, L-NAME, reduced the sensitivity of RGCs to light under light adaptation at different ambient light conditions. These observations were seen in all cells that recordings were made from. L-NAME diminished the excitatory synaptic currents (EPSCs), rather than increasing the inhibitory synaptic currents, of RGCs to reduce the sensitivity of RGCs to light. Cones may be the sites that L-NAME acted to diminish the EPSCs of RGCs.

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Light adaptation and responses to contrast flashes in cones of the walleye retina

Cited by 21 publications

References 22 publications

Mechanisms that limit the light stimulus frequency following through the dl-2-amino-4-phosphonobutyric acid sensitive and insensitive rod Off-pathways

Mechanisms that limit the light stimulus frequency following through the dl-2-amino-4-phosphonobutyric acid sensitive and insensitive rod Off-pathways

Light adaptation and photopigment bleaching in cone photoreceptors in situ in the retina of the turtle

Inhibition of nitric oxide synthase desensitizes retinal ganglion cells to light by diminishing their excitatory synaptic currents under light adaptation

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