Base de dados : LILACS
Pesquisa : F02.463.593.778.255.780 [Categoria DeCS]
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Texto completo SciELO Brasil
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Id: lil-718328
Autor: Chambeaud, Javier G; Martín, Andres; Barraza, Jose F.
Título: Effect of disparity on the perception of motion-defined contours
Fonte: Psychol. neurosci. (Impr.);7(2):91-101, Jan.-June 2014. ilus, graf.
Idioma: en.
Projeto: ANPCyT; . CIUNT.
Resumo: We present three experiments that explored the effect of binocular disparity on the perception of contours defined by motion in a Spatiotemporal Boundary Formation. Depending on the disparity, the stimulus is perceived as an object that moves behind a holed surface (occluded configuration) or as a luminous transparency that moves over a surface that contains dots (occluding configuration). In all of the experiments, we used a Vernier task to assess the strength of contour perception. In the first experiment, we measured acuity as a function of disparity for a range of speeds and dot densities. The results showed that, despite the difference in the percepts, acuity was similar in both situations, replicating the dependence on speed and dot density demonstrated in previous studies. In the second experiment, the results showed that the dynamics of contour integration were identical for both occluded and occluding configurations. In the third experiment, we tested whether the mechanism of contour integration works independently from the interpretation of the scene. In this experiment, we inverted the disparity during stimulus presentation so that the stimulus switched between occluded and occluding configurations. The results showed that the switch of the depth order increased the threshold to the value obtained with a shorter presentation time. This might be produced by a resetting of the integration process driven by the change of depth order. The results are discussed within a conceptual model that places the process of contour integration in the context of the perception of objects in a Spatiotemporal Boundary Formation...
Descritores: Percepção de Forma
Disparidade Visual
-Acuidade Visual
Limites: Humanos
Adulto
Responsável: BR85.1 - Biblioteca Dante Moreira Leite


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Texto completo SciELO Brasil
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Id: lil-360367
Autor: Bradshaw, Mark F; Hibbard, Paul B.
Título: Reaching for virtual objects: binocular disparity, retinal motion and the control of prehension
Fonte: Arq. bras. oftalmol;66(supl.5):53-61, set.-out. 2003. ilus, graf.
Idioma: en.
Projeto: Wellcome Trust.
Resumo: To reach for and grasp an object, its distance, shape and size must be known. In principle, the combination of disparity and motion information could be used to provide this information as the perception of object shape from disparity is biased and the perception of object size from motion is indeterminate. Here we investigate whether the visual system can take advantage of the simultaneous presence of both cues of both cues in the control of reaching and grasping. For both real and virtual objects, peak grip aperture scaled with object size and peak wrist velocity scaled with object distance. Kinematic indices, which reflect distance reached and perceived size, showed clear and systematic biases may be interpreted as arising from the biases in the use of binocular disparity, and the indeterminacy of the information provided by motion. Combining disparity and motion information improved estimates of the width, but not the depth or distance of objects. Overall, these results suggest that accurate metric depth information for the control of prehension is not available from binocular or motion cues, either in isolation or in combination.
Descritores: Percepção de Distância
Percepção de Tamanho
Disparidade Visual
Limites: Humanos
Responsável: BR1.2 - Biblioteca Central


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Id: lil-343426
Autor: Campos, Patricia; Guillén Pinto, Daniel.
Título: Enfermedad de Schilder: a propósito de un caso / Schilder disease: apropos of a case
Fonte: Rev. neuropsiquiatr;57(1):21-24, mar. 1994. ilus.
Idioma: es.
Resumo: La ahora denominada Leucodistrofia Adrenocortical tipo Schilder, representa una de las formas más graves de demencia asociada o pérdida visual y auditiva en la edad escolar. Presentamos un caso clínico y radiológicamente característico con el objeto de llamar la atención hacia su existencia y hacia la esperanza de poder ahora realizar diagnóstico pre-natal.
Descritores: Esclerose Cerebral Difusa de Schilder
-Demência
Perda Auditiva Bilateral
Disparidade Visual
Limites: Humanos
Masculino
Criança
Tipo de Publ: Revisão
Relatos de Casos
Responsável: PE1.1 - Oficina Universitária de Biblioteca


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Id: lil-280035
Autor: Beniz, José; Cialdini, Arnaldo; Avila, Marcos.
Título: Pulsoterapia com corticóide em fribrose sub-retiniana progressiva / Steroid pulsetherapy in progressive subretinal fibrosis
Fonte: Arq. bras. oftalmol;57(1):26-9, fev. 1994. ilus.
Idioma: pt.
Resumo: Uma criança de 10 anos, do sexo masculino, apresentou um caso raro de fibrose sub-retiniana progressiva.Inicialmente apenas o olho direito foi afetado.Sem tratamento, este processo evolui para formaçäo de uma extensa zona de fibrose sub-retiniana na área macular, com severo comprometimento visual.Após um ano e cinco meses apareceram lesöes coroidianas multifocais com deslocamento seroso macular no olho esquerdo, tendo sido precocemente tratadas com corticoesteróides.Houve resoluçäo rápida das lesöes, sem cicatrizaçäo sub-retiniana e o paciente manteve acuidade visual normal neste olho.
Descritores: Olho/patologia
Fibrose/complicações
Fibrose/reabilitação
Disparidade Visual
Limites: Humanos
Masculino
Criança
Tipo de Publ: Relatos de Casos
Responsável: BR734.1 - Biblioteca Central Cesar Lattes - BCCL



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