Biomaterial Database

Temporal summation in the achromat. 1988

L T Sharpe, and C Fach, and K Nordby

Neurologische Universitätsklinik, Freiburg, F.R.G.

We investigated temporal summation of the rods in a complete achromat, who lacks cone vision. Critical duration (tc) was estimated both at the achromat's preferred area of fixation and at an area 12 deg laterally in the nasal visual field. Comparable tc determinations were made in a normal trichromat. At background luminances of 0.0 and 0.6 scot. td, where the rods mediate detection, the values of tc were similar for the achromat and the normal. At a luminance of 813 scot. tds, however, where the middle-wavelength sensitive cones mediate detection in the trichromat, the tc for the achromat was much longer than that for the trichromat.

UI	MeSH Term	Description	Entries
D008027	Light	That portion of the electromagnetic spectrum in the visible, ultraviolet, and infrared range.	Light, Visible,Photoradiation,Radiation, Visible,Visible Radiation,Photoradiations,Radiations, Visible,Visible Light,Visible Radiations
D008297	Male		Males
D010783	Photometry	Measurement of the various properties of light.	Photometries
D010786	Photoreceptor Cells	Specialized cells that detect and transduce light. They are classified into two types based on their light reception structure, the ciliary photoreceptors and the rhabdomeric photoreceptors with MICROVILLI. Ciliary photoreceptor cells use OPSINS that activate a PHOSPHODIESTERASE phosphodiesterase cascade. Rhabdomeric photoreceptor cells use opsins that activate a PHOSPHOLIPASE C cascade.	Ciliary Photoreceptor Cells,Ciliary Photoreceptors,Rhabdomeric Photoreceptor Cells,Rhabdomeric Photoreceptors,Cell, Ciliary Photoreceptor,Cell, Photoreceptor,Cell, Rhabdomeric Photoreceptor,Cells, Ciliary Photoreceptor,Cells, Photoreceptor,Cells, Rhabdomeric Photoreceptor,Ciliary Photoreceptor,Ciliary Photoreceptor Cell,Photoreceptor Cell,Photoreceptor Cell, Ciliary,Photoreceptor Cell, Rhabdomeric,Photoreceptor Cells, Ciliary,Photoreceptor Cells, Rhabdomeric,Photoreceptor, Ciliary,Photoreceptor, Rhabdomeric,Photoreceptors, Ciliary,Photoreceptors, Rhabdomeric,Rhabdomeric Photoreceptor,Rhabdomeric Photoreceptor Cell
D003117	Color Vision Defects	Defects of color vision are mainly hereditary traits but can be secondary to acquired or developmental abnormalities in the CONES (RETINA). Severity of hereditary defects of color vision depends on the degree of mutation of the ROD OPSINS genes (on X CHROMOSOME and CHROMOSOME 3) that code the photopigments for red, green and blue.	Achromatopsia,Color Blindness,Monochromatopsia,Color Blindness, Acquired,Color Blindness, Blue,Color Blindness, Green,Color Blindness, Inherited,Color Blindness, Red,Color Blindness, Red-Green,Color Vision Deficiency,Deutan Defect,Protan Defect,Tritan Defect,Achromatopsias,Acquired Color Blindness,Blindness, Color,Blue Color Blindness,Color Blindness, Red Green,Color Vision Defect,Color Vision Deficiencies,Defect, Color Vision,Defect, Deutan,Defects, Color Vision,Deficiencies, Color Vision,Deficiency, Color Vision,Green Color Blindness,Inherited Color Blindness,Red Color Blindness,Red-Green Color Blindness,Vision Defect, Color,Vision Defects, Color,Vision Deficiencies, Color,Vision Deficiency, Color
D005403	Fixation, Ocular	Positioning and accommodation of eyes that allows the image to be brought into place on the FOVEA CENTRALIS of each eye.	Focusing, Ocular,Ocular Fixation,Eye Gaze,Eye Gazes,Gaze, Eye,Gazes, Eye,Ocular Focusing
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
D012684	Sensory Thresholds	The minimum amount of stimulus energy necessary to elicit a sensory response.	Sensory Threshold,Threshold, Sensory,Thresholds, Sensory
D013997	Time Factors	Elements of limited time intervals, contributing to particular results or situations.	Time Series,Factor, Time,Time Factor