The effects of eccentricity and spatial frequency on the orientation discrimination asymmetry
| Autor: | Frédéric J.A.M. Poirier, Rick Gurnsey |
|---|---|
| Rok vydání: | 1998 |
| Předmět: |
Adult
Male Retinal Ganglion Cells Fovea Centralis media_common.quotation_subject Experimental and Cognitive Psychology Frequency effect Stimulus (physiology) Biology Asymmetry Optics Foveal Orientation medicine Humans Visual Cortex media_common business.industry Fovea centralis Oblique case medicine.anatomical_structure Visual cortex Space Perception Female Computer Vision and Pattern Recognition Spatial frequency business Photic Stimulation |
| Zdroj: | Spatial Vision. 11:349-366 |
| ISSN: | 1568-5683 |
| Popis: | This study investigated the effects of eccentricity and spatial frequency on the discrimination of vertical and oblique (10 deg from vertical) Gabor patches. Within a display stimuli were scaled by a factor F = 1 + E/E2 at each eccentricity (E) in an attempt to equate either the number of photoreceptors (E2 = 2.5) or cortical area (E2 = 0.77) engaged at each eccentricity. The task was to detect a differently oriented target among eleven distractors. Orientation discrimination asymmetries (ODAs) were found such that an oblique stimulus was easier to detect in a background of vertical stimuli than vice versa. Subjects were equally sensitive to the two highest frequency Gabor patches and less sensitive to the lowest frequency Gabors. When stimuli were scaled with E2 = 2.5 sensitivity was constant at all eccentricities and the ODA magnitude was unaffected. When stimuli were magnified with E2 = 0.77 both sensitivity and ODA magnitude increased with eccentricity. Generally, we may conclude that the ODA effect is not a strictly foveal phenomenon nor is it a strictly high frequency effect. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
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