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Titolo:
Influence of contrast on the responses of marmoset lateral geniculate cells to drifting gratings
Autore:
Kremers, J; Silveira, LCL; Kilavik, BE;
Indirizzi:
Univ Tubingen, Hosp Eye, Dept Expt Ophthalmol, D-72076 Tubingen, Germany Univ Tubingen Tubingen Germany D-72076 halmol, D-72076 Tubingen, Germany Fed Univ Para, Dept Fisiol, BR-66075900 Belem, Para, Brazil Fed Univ ParaBelem Para Brazil BR-66075900 BC6075900 Belem, Para, Brazil
Titolo Testata:
JOURNAL OF NEUROPHYSIOLOGY
fascicolo: 1, volume: 85, anno: 2001,
pagine: 235 - 246
SICI:
0022-3077(200101)85:1<235:IOCOTR>2.0.ZU;2-F
Fonte:
ISI
Lingua:
ENG
Soggetto:
RETINAL GANGLION-CELLS; LINEAR SPATIAL SUMMATION; RECEPTIVE-FIELD; CALLITHRIX-JACCHUS; HUMAN OBSERVERS; X-CELLS; CAT; SENSITIVITY; NUCLEUS; MODULATION;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Life Sciences
Citazioni:
30
Recensione:
Indirizzi per estratti:
Indirizzo: Kremers, J Univ Tubingen, Hosp Eye, Dept Expt Ophthalmol, Rontgenweg 11, D-72076 Tubingen, Germany Univ Tubingen Rontgenweg 11 Tubingen Germany D-72076 , Germany
Citazione:
J. Kremers et al., "Influence of contrast on the responses of marmoset lateral geniculate cells to drifting gratings", J NEUROPHYS, 85(1), 2001, pp. 235-246

Abstract

The responses of lateral geniculate nucleus (LGN) cells in the common marmoset (Callithrix jacchus) to drifting luminance or cone isolating gratings of different spatial frequencies and contrasts were measured. The response noise, defined as the variability of the responses to single sweeps in the complex plane, was independent of stimulus contrast and spatial frequency but increased with increasing overall responsiveness of the cell. The signal-to-noise ratio of parvocellular (PC) cells was smaller than of magnocellular (MC) cells. At each contrast, the response amplitude as a function of spatial frequency could be described with a difference of Gaussians model. With this model, the sizes and the peak sensitivities of the receptive field centers and surrounds were estimated. It was found that receptive field center and surround sizes of LGN cells decrease slightly with increasing contrast. Further, the peak sensitivity decreases with increasing contrast. The two factors are involved in a decrease in responsivity (the response per unit contrast) with increasing contrast which is compatible to response saturation for low spatial frequency stimuli. PC cells did not saturate as much to luminance stimuli although some saturation was found with cone isolatinggratings. We found that the response phase lag of both PC and MC cells decreased with increasing contrast, which cannot be explained on the basis of linear response behavior. Apparently the phase of LGN cell responses to drifting gratings is altered in comparison with the retinal inputs by additional nonlinearities.

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Documento generato il 09/04/20 alle ore 12:27:09