منابع مشابه
Spatial summation of face information
Do all parts of the face contribute equally to face detection or are some parts more detectable than others? To evaluate this issue, we studied detection of the presence of normalized frontal-face images within aperture windows of varying extent. We performed a face summation study using two-alternative forced-choice psychophysics. The face stimuli were scaled to equal eye-to-chin distance, cen...
متن کاملCompressive spatial summation in human visual cortex.
Neurons within a small (a few cubic millimeters) region of visual cortex respond to stimuli within a restricted region of the visual field. Previous studies have characterized the population response of such neurons using a model that sums contrast linearly across the visual field. In this study, we tested linear spatial summation of population responses using blood oxygenation level-dependent ...
متن کاملSenescent changes in photopic spatial summation.
Previous studies have demonstrated an inverse relation between the size of the complete spatial summation area and ganglion cell density. We hypothesized that if this relation is dynamic, the spatial summation area at 6° nasal would expand to compensate for age-related losses of retinal ganglion cells but not in the fovea where age-related loss in ganglion cell density is not significant. This ...
متن کاملSeeing visual word forms: Spatial summation, eccentricity and spatial configuration
We investigated observers' performance in detecting and discriminating visual word forms as a function of target size and retinal eccentricity. The contrast threshold of visual words was measured with a spatial two-alternative forced-choice paradigm and a PSI adaptive method. The observers were to indicate which of two sides contained a stimulus in the detection task, and which contained a real...
متن کاملVisual spatial summation in macaque geniculocortical afferents.
The spatial summation properties of visual signals were analyzed for geniculocortical afferents in the primary visual cortex (V1) of anesthetized paralyzed macaque monkeys. Afferent input responses were recorded extracellularly during cortical inactivation through superfusion of the cortex with muscimol, allowing investigation of lateral geniculate nucleus of the thalamus (LGN) cell properties ...
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ژورنال
عنوان ژورنال: Journal of the Optical Society of America A
سال: 1985
ISSN: 1084-7529,1520-8532
DOI: 10.1364/josaa.2.001769