Licht-im-Terrarium: Literaturdatenbank
Licht-im-Terrarium: Literaturdatenbank |
|
 |
|
Ventura, D. F., de Souza, J. M., Devoe, R., & Zana, Y. (1999). Uv responses in the retina of the turtle. Visual Neuroscience, 16(2), 191–204. Added by: Sarina (2008-12-16 20:27:08) Last edited by: Sarina (2009-04-06 15:35:54) |
| Resource type: Journal Article DOI: 10.1017/S0952523899162011 BibTeX citation key: Ventura1999 View all bibliographic details  |
Categories: Englisch = English Keywords: Netzhaut = Retina, Schildkröten = Turtles, Sehvermögen = Visual Perception, Ultraviolett = Ultraviolet Creators: Devoe, de Souza, Ventura, Zana Collection: Visual Neuroscience |
Views: 3/836 Views index: % Popularity index: 0.25% |
| Abstract |
|
To study processing of UV stimuli in the retina of the turtle, Trachemys dorbignii, we recorded intracellular responses to spectral light from 89 cells: 54 horizontal (47 monophasic, five (R/G) biphasic and two (Y/B) triphasic), 14 bipolar, 12 amacrine, and nine ganglion cells. Spectral sensitivities were measured with monochromatic flashes or with the dynamic constant response method in dark or chromatic adapted states. Stray light and second-order harmonics were also measured. (1) All cells responded to UV stimuli, although none had maximum sensitivity in the UV. (2) Most horizontal, bipolar, and amacrine cells had red-peaked spectral sensitivities. (3) Red adaptation of all monophasic horizontal cells indicated a single red input, except one that had additional peaks in the blue and UV. (4) Responses of biphasic and triphasic horizontal cells to UV light were always hyperpolarizing. Opposition between hyperpolarizing and depolarizing responses at long wavelengths indicates that UV responses were not due to the beta band of red receptors. (5) An unstained spectrally opponent bipolar cell hyperpolarized in the center to green light and antagonistically depolarized in the surround to UV, blue, and green flashes, but hyperpolarized to red. (6) All dark-adapted amacrine cells were red-peaked monophasic cells, but red adaptation broadened their spectral-sensitivity curves or displaced their peaks. An A15, an A18, and an A24 wide-field amacrine cell were stained. (7) A G15 bistratified ganglion cell is shown here for the first time to be spectrally opponent. This UVB/RG cell depolarized to UV and blue and hyperpolarized to red and green. It differs from previously reported turtle ganglion cells in being color opponent in the entire field, not only in the surround, and in showing spatial opponency. Key Words: Ultraviolet vision; Turtle retina; Spectral sensitivity; Retinal electrophysiology; Intracellular recording. Added by: Sarina Last edited by: Sarina |