Biomaterial Database

Orientation acuity for sine-wave gratings with random variation of spatial frequency. 1993

D W Heeley, and H M Buchanan-Smith, and S Heywood

Department of Psychology, University of St Andrews, Fife, Scotland.

Orientation discrimination thresholds were estimated for sine-wave grating stimuli using a two-alternative forced-choice procedure on the two principal, and the two main oblique axes. The two discriminanda within any trial were subject to independent random variation of their spatial frequency. The variation of spatial frequency was defined by a Gaussian probability density function. Thresholds were obtained for five different depths of frequency variation within the range 0.0-1.0 octave. We find that orientation acuity on any of the axes tested is unaffected by variation in the spatial frequency of the targets. The data support the hypothesis that orientation and spatial frequency are independent and orthogonal neural codes.

UI	MeSH Term	Description	Entries
D010364	Pattern Recognition, Visual	Mental process to visually perceive a critical number of facts (the pattern), such as characters, shapes, displays, or designs.	Recognition, Visual Pattern,Visual Pattern Recognition
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
D011897	Random Allocation	A process involving chance used in therapeutic trials or other research endeavor for allocating experimental subjects, human or animal, between treatment and control groups, or among treatment groups. It may also apply to experiments on inanimate objects.	Randomization,Allocation, Random
D004192	Discrimination, Psychological	Differential response to different stimuli.	Discrimination, Psychology,Psychological Discrimination
D006801	Humans	Members of the species Homo sapiens.	Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man
D012399	Rotation	Motion of an object in which either one or more points on a line are fixed. It is also the motion of a particle about a fixed point. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)	Clinorotation,Clinorotations,Rotations
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
D014792	Visual Acuity	Clarity or sharpness of OCULAR VISION or the ability of the eye to see fine details. Visual acuity depends on the functions of RETINA, neuronal transmission, and the interpretative ability of the brain. Normal visual acuity is expressed as 20/20 indicating that one can see at 20 feet what should normally be seen at that distance. Visual acuity can also be influenced by brightness, color, and contrast.	Acuities, Visual,Acuity, Visual,Visual Acuities