Biomaterial Database

Threshold temporal integration of chromatic stimuli. 1984

V C Smith, and R W Bowen, and J Pokorny

We measured colorimetric purity thresholds as a function of stimulus duration for seven wavelengths between 430 and 650 nm. Purity thresholds were measured in a hue substitution mode. The purity-duration function showed decreasing purity as duration was increased to about 640 msec. Functions for different wavelengths could be fit by a fixed chromatic template displaced on the purity axis. Increment thresholds as a function of duration were measured for white and chromatic lights added to a homogeneous white stimulus field. The "white" function showed no integration beyond 160 msec and was fit by an achromatic template. The wavelength functions were not parallel; wavelengths at the spectral extremes showed longer integration times, similar to the purity-duration functions. Increment data could be fit by a vector sum of chromatic and achromatic templates.

UI	MeSH Term	Description	Entries
D010775	Photic Stimulation	Investigative technique commonly used during ELECTROENCEPHALOGRAPHY in which a series of bright light flashes or visual patterns are used to elicit brain activity.	Stimulation, Photic,Visual Stimulation,Photic Stimulations,Stimulation, Visual,Stimulations, Photic,Stimulations, Visual,Visual Stimulations
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
D003118	Color Perception	Mental processing of chromatic signals (COLOR VISION) from the eye by the VISUAL CORTEX where they are converted into symbolic representations. Color perception involves numerous neurons, and is influenced not only by the distribution of wavelengths from the viewed object, but also by its background color and brightness contrast at its boundary.	Color Perceptions,Perception, Color,Perceptions, Color
D006801	Humans	Members of the species Homo sapiens.	Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man
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