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Titolo:
THE DYNAMIC NONLINEAR BEHAVIOR OF FLY PHOTORECEPTORS EVOKED BY A WIDE-RANGE OF LIGHT INTENSITIES
Autore:
FRENCH AS; KORENBERG MJ; JARVILEHTO M; KOUVALAINEN E; JUUSOLA M; WECKSTROM M;
Indirizzi:
UNIV ALBERTA,DEPT PHYSIOL EDMONTON T6G 2H7 ALBERTA CANADA QUEENS UNIV,DEPT ELECT ENGN KINGSTON K7L 3N6 ONTARIO CANADA UNIV OULU,DEPT ZOOL SF-90100 OULU 10 FINLAND UNIV OULU,DEPT PHYSIOL SF-90100 OULU 10 FINLAND
Titolo Testata:
Biophysical journal
fascicolo: 2, volume: 65, anno: 1993,
pagine: 832 - 839
SICI:
0006-3495(1993)65:2<832:TDNBOF>2.0.ZU;2-F
Fonte:
ISI
Lingua:
ENG
Soggetto:
WHITE-NOISE ANALYSIS; DROSOPHILA PHOTORECEPTORS; LOCUST PHOTORECEPTORS; POTASSIUM CHANNELS; ADAPTATION; IDENTIFICATION; TRANSDUCTION; SYSTEMS; RETINA; SIGNAL;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Citazioni:
45
Recensione:
Indirizzi per estratti:
Citazione:
A.S. French et al., "THE DYNAMIC NONLINEAR BEHAVIOR OF FLY PHOTORECEPTORS EVOKED BY A WIDE-RANGE OF LIGHT INTENSITIES", Biophysical journal, 65(2), 1993, pp. 832-839

Abstract

Fly photoreceptor cells were stimulated with steps of light over a wide intensity range. First- and second-order Volterra kernels were thencomputed from sequences of combined step responses. Diagonal values of the second-order Volterra kernels were much greater than the off-diagonal values, and the diagonal values were roughly proportional to thecorresponding first-order kernels, suggesting that the response couldbe approximated by a static nonlinearity followed by a dynamic linearcomponent (Hammerstein model). The amplitudes of the second-order kernels were much smaller in light-adapted than in dark-adapted photoreceptors. Hammerstein models constructed from the step input/output measurements gave reasonable approximations to the actual photoreceptor responses, with light-adapted responses being relatively better fitted. However, Hammerstein models could not account for several features of the photoreceptor behavior, including the dependence of the step response shape on step amplitude. A model containing an additional static nonlinearity after the dynamic linear component gave significantly better fits to the data. These results indicate that blowfly photoreceptorshave a strong early gain control nonlinearity acting before the processes that create the characteristic time course of the response, in addition to the nonlinearities caused by membrane conductances.

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Documento generato il 30/11/20 alle ore 16:15:57