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 sec. are obtained in both species. For the photopic response fusion frequencies up to 50 flashes per sec. are seen in Tarentola, and up to 25 flashes per sec. 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 mµ. During dark adaptation the change of threshold after exposure to moderate and weak lights (up to 103 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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1 July 1961
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July 01 1961
The Duplex Nature of the Retina of the Nocturnal Gecko as Reflected in the Electroretinogram
Eberhard Dodt,
Eberhard Dodt
From the William G. Kerckhoff-Herzforschungsinstitut der Max-Planck-Gesellschaft, Bad Nauheim, Germany
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Karl Heinz Jessen
Karl Heinz Jessen
From the William G. Kerckhoff-Herzforschungsinstitut der Max-Planck-Gesellschaft, Bad Nauheim, Germany
Search for other works by this author on:
Eberhard Dodt
From the William G. Kerckhoff-Herzforschungsinstitut der Max-Planck-Gesellschaft, Bad Nauheim, Germany
Karl Heinz Jessen
From the William G. Kerckhoff-Herzforschungsinstitut der Max-Planck-Gesellschaft, Bad Nauheim, Germany
Received:
November 07 1960
Online ISSN: 1540-7748
Print ISSN: 0022-1295
Copyright, 1961, by The Rockefeller Institute
1961
J Gen Physiol (1961) 44 (6): 1143–1158.
Article history
Received:
November 07 1960
Citation
Eberhard Dodt, Karl Heinz Jessen; The Duplex Nature of the Retina of the Nocturnal Gecko as Reflected in the Electroretinogram . J Gen Physiol 1 July 1961; 44 (6): 1143–1158. doi: https://doi.org/10.1085/jgp.44.6.1143
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