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1	Red-green and blue-yellow mechanisms are matched in sensitivity for temporal and spatial modulation. McKeefry, Declan J., Murray, I.J., Kulikowski, J.J. January 2001 (has links) No / The spatial and temporal properties of human colour vision are examined using isoluminant, red¿green and blue¿yellow tritanopic gratings. Chromatic sensitivity is found to be low-pass as a function of both spatial and temporal frequency along all the chromatic axes investigated, including the tritanopic confusion lines employed to examine the properties of the S-cone driven mechanism. Comparison of sensitivity to on-off and contrast reversing stimuli indicates that transient mechanisms contribute to the detection of red¿green patterns but that the detection of S-cone specific patterns is governed by sustained mechanisms. By compensating for transient contributions to red¿green sensitivity, it is shown that sensitivity of chromatic mechanisms dominated by L- and M-cone input are closely matched to those with S-cone input. Colour Isoluminance Tritanopic Cone-contrast sensitivity
2	Ryškio ir spalvos kontrasto įtaka stimulo geometrijos suvokimo iškraipymams / Influence of colour and luminance contrast on perceptual distortions of stimulus geometry Surkys, Tadas 03 April 2007 (has links) Distortions of perception of the Müller-Lyer, Delboeuf, Oppel-Kundt and Zöllner type have been studied in psychophysical experiments conducted under computer control with a program of our own design arranging the stimuli, presenting them on the monitor, introducing alterations according to the subject’s command, recording responses, and handling the results. Our illusory figures designed by heteroluminant colours yielded the effects of perceived distortion qualitatively and quantitatively similar to the effects evoked by the white and black figures. Variations of luminance of colours of the figures and backgrounds within a relatively wide interval of its values did not evoke a noticeable change in strength of the perceived distortions, but if the luminance of the stimulus colour approached the magnitude which was determined as isoluminant with the background colour, the strength of the distortions changed significantly; it increased for the Brentano figure and decreased for the Delboeuf, Oppel-Kundt and Zöllner figures. The curves obtained for different subjects with different colour combinations were similar in shape, though horizontal parts and peaks of the curve were not at the same level. For isoluminant figures, the experimental curves demonstrating the strength variations of the perceived distortions in dependence of spatial parameters of the stimuli were similar in shape with the curves for heteroluminant figures, but lay above (Brentano) or below (Delboeuf... [to full text] Biology Spalvos kontrastas Geometrinės iliuzijos Geometrical illusions Neuromodelling Regimasis suvokimas Visual perception Isoluminance Neuromodeliavimas
3	Seeing Differently in Near and Far Li, Tao 10 1900 (has links) <p>Based on evidence from studies involving animal single cell recording, animal brain lesion, and human brain damage, researchers have suggested that there may be differential visual representations for objects in near (peripersonal, within arm’s reach) and far (extrapersonal, beyond arm’s reach) space in the human visual system. The findings in Chapter 2 and Chapter 3 of the present thesis provide the first behavioural evidence suggesting that healthy human observers prefer to rely on different visual mechanisms in processing information in near and far spaces. The different performance in detecting visual targets presented in near and far space indicates that the brain can actively modulate the information processing either in parvocellular and magnocellular pathways or in ventral and dorsal streams. <br /> To determine the loci of the neural modulation regarding near and far viewing, visual identification tasks were employed in Chapter 4. In four experiments, visual stimuli were presented in either isoluminant green or achromatic white in order to decouple the neural processing in parvocellular and magnocellular pathways. The different patterns of the visual performance in the four experiments suggest that the change to near or far viewing distance results in altered information transmission in parvocellular and magnocellular pathways. Thus, the data in the present thesis provide the first behavioural evidence indicating that the LGN serves as a gatekeeper for regulating and redistributing visual information for later cortical analysis.</p> / Doctor of Science (PhD) Peripersonal/extrapersonal space isoluminance detection identification visual pathways. Cognition and Perception Cognition and Perception
4	An fMRI study of chromatic processing in humans / Untersuchung der menschlichen Farbverarbeitung mittels fMRT D'Souza, Dany Vijay 09 September 2009 (has links) No description available. 500 Naturwissenschaften MED 372 Mathematics and Natural Science fMRT Farbensehen visueller Kortex Retinotopie Isoluminanz Zeitfrequenz Ortsfrequenz Gesichtsfeld Exzentrizität chromatisch Leuchtdichte fMRI color vision visual cortex retinotopy isoluminance temporal frequency spatial frequency visual field eccentricity chromatic luminance 42.99 44.03

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