Biomaterial Database

Modeling shifts in perceived spatial frequency between the fovea and the periphery. 1990

E T Davis

Department of Visual Sciences, State College of Optometry, State University of New York, New York 10010.

A quantitative multiple-channels model can account for changes in perceived spatial frequency between foveally and peripherally viewed patterns; these frequency shifts are as large as 0.47 octave (38.5%). Factors that change as a function of eccentricity and that can alter the appearance of visual patterns include (1) scaling of receptive-field sizes, (2) overall sensitivity, and (3) steepness and nonlinearity of contrast-transfer functions (CTF's). Computations based on receptive-field size scaling, combined with fixed perceptual labels, predict higher perceived spatial frequency for peripheral patterns. Computations based on reduced sensitivity, however, predict the opposite result and thus partially offset the effect of receptive-field size scaling. The predicted perceived-frequency shifts based on changes in CTF's are quite small and can be ignored. Both individual differences and visual-field-location differences in magnitudes of perceived-frequency shifts are predicted by the model. An alternative perceptual explanation based on size-distance invariance and size constancy is also evaluated.

UI	MeSH Term	Description	Entries
D008266	Macula Lutea	An oval area in the retina, 3 to 5 mm in diameter, usually located temporal to the posterior pole of the eye and slightly below the level of the optic disk. It is characterized by the presence of a yellow pigment diffusely permeating the inner layers, contains the fovea centralis in its center, and provides the best phototropic visual acuity. It is devoid of retinal blood vessels, except in its periphery, and receives nourishment from the choriocapillaris of the choroid. (From Cline et al., Dictionary of Visual Science, 4th ed)	Lutea, Macula,Luteas, Macula,Macula Luteas
D008960	Models, Psychological	Theoretical representations that simulate psychological processes and/or social processes. These include the use of mathematical equations, computers, and other electronic equipment.	Model, Mental,Model, Psychological,Models, Mental,Models, Psychologic,Psychological Models,Mental Model,Mental Models,Model, Psychologic,Psychologic Model,Psychologic Models,Psychological Model
D011601	Psychophysics	The science dealing with the correlation of the physical characteristics of a stimulus, e.g., frequency or intensity, with the response to the stimulus, in order to assess the psychologic factors involved in the relationship.	Psychophysic
D005544	Forecasting	The prediction or projection of the nature of future problems or existing conditions based upon the extrapolation or interpretation of existing scientific data or by the application of scientific methodology.	Futurology,Projections and Predictions,Future,Predictions and Projections
D005584	Fovea Centralis	An area approximately 1.5 millimeters in diameter within the macula lutea where the retina thins out greatly because of the oblique shifting of all layers except the pigment epithelium layer. It includes the sloping walls of the fovea (clivus) and contains a few rods in its periphery. In its center (foveola) are the cones most adapted to yield high visual acuity, each cone being connected to only one ganglion cell. (Cline et al., Dictionary of Visual Science, 4th ed)
D001696	Biomechanical Phenomena	The properties, processes, and behavior of biological systems under the action of mechanical forces.	Biomechanics,Kinematics,Biomechanic Phenomena,Mechanobiological Phenomena,Biomechanic,Biomechanic Phenomenas,Phenomena, Biomechanic,Phenomena, Biomechanical,Phenomena, Mechanobiological,Phenomenas, Biomechanic
D013028	Space Perception	The awareness of the spatial properties of objects; includes physical space.	Perception, Space,Perceptions, Space,Space Perceptions
D014163	Transfer, Psychology	Change in learning in one situation due to prior learning in another situation. The transfer can be positive (with second learning improved by first) or negative (where the reverse holds).	Transfer (Psychology),Transfer of Learning,Transfer of Training,Learning Transfer,Psychology Transfer,Psychology Transfers,Training Transfer,Transfers (Psychology),Transfers, Psychology
D014794	Visual Fields	The total area or space visible in a person's peripheral vision with the eye looking straightforward.	Field, Visual,Fields, Visual,Visual Field
D015350	Contrast Sensitivity	The ability to detect sharp boundaries (stimuli) and to detect slight changes in luminance at regions without distinct contours. Psychophysical measurements of this visual function are used to evaluate VISUAL ACUITY and to detect eye disease.	Visual Contrast Sensitivity,Sensitivity, Contrast,Sensitivity, Visual Contrast