Accession Number : ADA189781

Title :   Laboratory Equipment Update.

Descriptive Note : Final rept. 1 Sep 86-31 Aug 87,

Corporate Author : YALE UNIV NEW HAVEN CONN SCHOOL OF MEDICINE

Personal Author(s) : Hirsch, Joy

PDF Url : ADA189781

Report Date : 31 Oct 1987

Pagination or Media Count : 14

Abstract : We have digitized the cone centers of a primate and a human photoreceptor lattice and have determined that the Nyquist limit predicts visual resolution out to nearly two degrees of retinal eccentricity. Beyond 2 degrees lattice disorder appears to have a deleterious factors between cone density and aperture size. A developing model of lattice structure and design strategies reflects complex principles involved in the evolution of human spatial vision. We are currently exploring a bottom up model of human vision where sampling limitations are propagated along the spatial vision processing hierarchy. The observations that this model addresses include a new class of two dimensional spatial discriminated more accurately than the bisection of two points of comparable separation. This discovery has led to the development of two additional lines of research, area discrimination and dot density discrimination. We have identified a fundamental similarity between spatial frequency discrimination and vernier acuity that demonstrates that Weber's Law applied similarity to both tasks. Further, we have shown that two-dot vernier discrimination falls off within two degrees of retinal eccentricity similarly to changes in retinal sampling. These findings contribute to a model of spatial discriminations that includes limits imposed at the sampling level of the visual process.

Descriptors :   *VISION, *PHOTORECEPTORS, *ANATOMICAL MODELS, ACUITY, APERTURES, CONICAL BODIES, DENSITY, DISCRIMINATION, ECCENTRICITY, FREQUENCY, HIERARCHIES, HUMANS, LABORATORY EQUIPMENT, LIMITATIONS, MODELS, PROCESSING, RETINA, SAMPLING, SEPARATION, SIZES(DIMENSIONS), SPATIAL DISTRIBUTION

Subject Categories : Anatomy and Physiology

Distribution Statement : APPROVED FOR PUBLIC RELEASE