Biomaterial Database

Spatial-frequency adaptation affects spatial-probability summation. 1983

D W Williams, and H R Wilson

The effects of spatial-frequency adaptation on spatial-probability summation were investigated by two techniques: the measurement of the dependence of cosine grating sensitivity on the number of cycles presented and the determination of the frequency-of-seeing curve for a cosine grating. Both measurements indicate that the contribution of spatial-probability summation to adapted grating thresholds is reduced in comparison with unadapted conditions. This reduction in the effects of spatial-probability summation, together with the decrease in local sensitivity, which depends on the spatial inhomogeneity of the visual system, is sufficient to account for the threshold elevation aftereffect measured when adapting and testing with cosine gratings.

UI	MeSH Term	Description	Entries
D012160	Retina	The ten-layered nervous tissue membrane of the eye. It is continuous with the OPTIC NERVE and receives images of external objects and transmits visual impulses to the brain. Its outer surface is in contact with the CHOROID and the inner surface with the VITREOUS BODY. The outer-most layer is pigmented, whereas the inner nine layers are transparent.	Ora Serrata
D004056	Differential Threshold	The smallest difference which can be discriminated between two stimuli or one which is barely above the threshold.	Difference Limen,Just-Noticeable Difference,Weber-Fechner Law,Difference Limens,Difference, Just-Noticeable,Differences, Just-Noticeable,Differential Thresholds,Just Noticeable Difference,Just-Noticeable Differences,Law, Weber-Fechner,Limen, Difference,Limens, Difference,Threshold, Differential,Thresholds, Differential,Weber Fechner Law
D006801	Humans	Members of the species Homo sapiens.	Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man
D000221	Adaptation, Ocular	The adjustment of the eye to variations in the intensity of light. Light adaptation is the adjustment of the eye when the light threshold is increased; DARK ADAPTATION when the light is greatly reduced. (From Cline et al., Dictionary of Visual Science, 4th ed)	Light Adaptation,Adaptation, Light,Adaptations, Light,Adaptations, Ocular,Light Adaptations,Ocular Adaptation,Ocular Adaptations
D013028	Space Perception	The awareness of the spatial properties of objects; includes physical space.	Perception, Space,Perceptions, Space,Space Perceptions
D055095	Optics and Photonics	A specialized field of physics and engineering involved in studying the behavior and properties of light and the technology of analyzing, generating, transmitting, and manipulating ELECTROMAGNETIC RADIATION in the visible, infrared, and ultraviolet range.	Photonics,Photonics and Optics