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Titolo:
Temporal sensitivity of human luminance pattern mechanisms determined by masking with temporally modulated stimuli
Autore:
Boynton, GM; Foley, JM;
Indirizzi:
Salk Inst Biol Studies, SNL B, San Diego, CA 92186 USA Salk Inst Biol Studies San Diego CA USA 92186 B, San Diego, CA 92186 USA Univ Calif Santa Barbara, Dept Psychol, Santa Barbara, CA 93106 USA Univ Calif Santa Barbara Santa Barbara CA USA 93106 Barbara, CA 93106 USA
Titolo Testata:
VISION RESEARCH
fascicolo: 9, volume: 39, anno: 1999,
pagine: 1641 - 1656
SICI:
0042-6989(199905)39:9<1641:TSOHLP>2.0.ZU;2-9
Fonte:
ISI
Lingua:
ENG
Soggetto:
HUMAN-VISION; SUSTAINED CHANNELS; CONTRAST MASKING; REACTION-TIME; TRANSIENT; MODEL; DISCRIMINATION; SELECTIVITY; THRESHOLD; GRATINGS;
Keywords:
masking; spatio-temporal frequency; inhibition; contrast;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Life Sciences
Citazioni:
45
Recensione:
Indirizzi per estratti:
Indirizzo: Boynton, GM Salk Inst Biol Studies, SNL B, POB 85800, San Diego, CA 92186 USA Salk Inst Biol Studies POB 85800 San Diego CA USA 92186 86 USA
Citazione:
G.M. Boynton e J.M. Foley, "Temporal sensitivity of human luminance pattern mechanisms determined by masking with temporally modulated stimuli", VISION RES, 39(9), 1999, pp. 1641-1656

Abstract

Target contrast thresholds were measured using vertical spatial Gabor targets in the presence of full field maskers of the same spatial frequency andorientation. In the first experiment both target and masker were 2 cpd. The target was modulated at a frequency of 1 or 10 Hz and the maskers varied in temporal frequency from 1 to 30 Hz and in contrast from 0.03 to 0.50. Inthe second experiment both target and masker had a spatial frequency of 1,5 or 8 cpd. The target was modulated at 7.5 Hz and the same set of maskerswas used as in the first experiment. The results are not consistent with awidely used model that is based on mechanisms in which excitation is summed linearly and the sum is transformed by an S-shaped nonlinear excitation-response function. A new model of human pattern vision mechanisms, which hasexcitatory and divisive inhibitory inputs, describes the results well. Parameters from the best fit of the new model to the results of the first experiment show that the 1 Hz and 10 Hz targets were detected by mechanisms with temporal low-pass and band-pass excitatory sensitivity, respectively. Fits to the second experiment suggest that at 1 cpd, the excitatory tuning of the detecting mechanism is band-pass. At 5 and 8 cpd, the mechanisms are excited by a broad range of temporal frequencies. Mechanism sensitivity to divisive inhibition depends on temporal frequency in the same general way as sensitivity to excitation. Mechanisms are more broadly tuned to divisive inhibition than to excitation, except when the target temporal frequency is high. (C) 1999 Elsevier Science Ltd. All rights reserved.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 03/12/20 alle ore 12:47:31