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Sensitivity transformation for vertebrate vision

Published online by Cambridge University Press:  02 June 2009

Richard L. Chappell
Affiliation:
Department of Biological Sciences, Hunter College and City University of New York Graduate Center, New York
Ken-Ichi Naka
Affiliation:
Department of Ophthalmology, New York University Medical Center, New York

Abstract

The visual response to a flash given in the dark is known to saturate according to the Michaelis-Menten relationship. Nevertheless, the incremental response from increasing levels of mean luminance tends to follow a Weber-Fechner relationship well into the saturation range determined from the Michaelis-Menten results. This sensitivity transformation from Michaelis-Menten to Weber-Fechner is an important characteristic of light adaptation in the vertebrate retina. Recent studies concerning the role of calcium in photoreceptor adaptation have shown that the relaxation from peak to plateau in the response of isolated photoreceptors was absent under conditions in which adaptation was blocked. Comparing the pronounced relaxation from peak to plateau in turtle horizontal cells with the absence of such relaxation in the catfish response, we noted also that turtle incremental sensitivity shows a Weber-Fechner relationship while catfish incremental sensitivity more closely follows the local slope of the Michaelis-Menten relation. Based on these observations, we have obtained an expression to relate the relaxation from peak to plateau with the sensitivity transformation. We assume that adaptation shifts the half-maximum point of the Michaelis-Menten curve so that the light response relaxes to a plateau value equal to a specified fraction φ of the peak response. We show that this manipulation alone results in a transformation from Michaelis-Menten kinetics to Weber-Fechner sensitivity.

Type
Research Articles
Copyright
Copyright © Cambridge University Press 1991

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References

Barlow, H.B. & Sparrock, J.M.B. (1964). The role of after-images in dark adaptation. Science 144, 13091314.CrossRefGoogle ScholarPubMed
Chappell, R.L., Naka, K.-I. & Sakuranaga, M. (1985). Dynamics of turtle horizontal cell response. Journal of General Physiology 86, 423453.CrossRefGoogle ScholarPubMed
Dawis, S.M. (1979). Light adaptation in cone photoreceptors: the occurrence and significance of unitary adaptive strength. Biological Cybernetics 34, 3541.CrossRefGoogle ScholarPubMed
Fain, G.L. (1976). Sensitivity of toad rods: dependence on wavelength and background illumination. Journal of Physiology 261, 71101.CrossRefGoogle ScholarPubMed
Matthews, H.R., Fain, G.L., Murphy, R.L.W., & Lamb, T.D. (1990). Light adaptation in cone photoreceptors of the salamander: a role for cytoplasmic calcium. Journal of Physiology 420, 447469.CrossRefGoogle ScholarPubMed
Matthews, H.R., Murphy, R.L.W., Fain, G.L. & Lamb, T.D. (1988). Photoreceptor light adaptation is mediated by cytoplasmic calcium concentration. Nature 334, 6769.CrossRefGoogle ScholarPubMed
Naka, K-I., Chan, R.Y. & Yasui, S. (1979). Adaptation in catfish retina. Journal of Neurophysiology 42, 441454.CrossRefGoogle ScholarPubMed
Naka, K.-I. & Chappell, R.L. (1984). Seeing in the light. In Animal Behavior: Neurophysiological and Ethological Approaches, ed. Aoki, K. et al., pp. 125135. Berlin: Springer-Verlag.Google Scholar
Naka, K.-I. & Rushton, W.A.H. (1966). S potentials from luminosity units in the retina of fish (Cyprinidae). Journal of Physiology 185, 587599.CrossRefGoogle ScholarPubMed
Nakatani, K. & Yau, K.-W. (1988 a). Calcium and light adaptation in retinal rods and cones. Nature 334, 6971.CrossRefGoogle ScholarPubMed
Nakatani, K. & Yau, K.-W. (1988 b). Sodium-dependent calcium extrusion and sensitivity regulation in retinal cones of the salamander. Journal of Physiology 409, 525548.CrossRefGoogle Scholar
Rushton, W.A.H. (1965). The Ferrier Lecture, 1962: visual adaptation. Proceedings of the Royal Society B (London) 162, 2046.Google Scholar
Shapley, R. & Enroth–Cugell, C. (1984). Visual adaptation and retinal gain controls. In Progress in Retinal Research, ed. Osborne, N.N. & Chader, G.J., pp. 263346. Oxford: Pergamon Press.Google Scholar
Williams, T.P. & Gale, J.G. (1977). A critique of an incremental threshold function. Vision Research 17, 881882.CrossRefGoogle ScholarPubMed
Williams, T.P. & Gale, J.G. (1978). “Compression” of retinal responsivity: V-logI functions and increment thresholds. Vision Research 18, 587590.CrossRefGoogle Scholar
Witkovsky, P. (1980). Excitation and adaptation in the vertebrate retina. In Current Topics in Eye Research, ed. Davson, H. & Zadunaisky, J., pp. 166. New York: Academic Press.Google Scholar