scholarly journals Uncertainty representation of low-level visual attributes

2011 ◽  
Vol 11 (11) ◽  
pp. 807-807
Author(s):  
M. Popovic ◽  
D. Lisitsyn ◽  
P. Berkes ◽  
M. Lengyel ◽  
J. Fiser
Perception ◽  
1997 ◽  
Vol 26 (1_suppl) ◽  
pp. 304-304
Author(s):  
T V Papathomas ◽  
I Kovács ◽  
A Feher

The need to revise the eye competition hypothesis of binocular rivalry, and to include the role of stimulus competition has been demonstrated recently by Kovács, Papathomas, Feher, and Yang (1996 Proceedings of the National Academy of Sciences of the USA93 15508 – 15511) and Logothetis, Leopold, and Sheinberg [1996 Nature (London)380 621 – 624]. Kovács et al showed that observers can obtain one-colour percepts when presented with chromatically rivalrous stimuli, even when there are targets of two different colours in each eye. In this study we investigate whether other attributes, in addition to colour, can drive interocular grouping, and how they interact. We extended the ‘patchwork’ rivalrous stimuli (Kovács et al) to study how colour, orientation, spatial frequency, and motion can group interocularly, and how they interact in grouping. Gabor patches are used, because they allow conjunctions of attributes to be formed systematically. To study the ability of an attribute (or a combination of attributes) to group interocularly, we induce rivalry by virtue of interocular differences in that attribute (or combination), and keep the other attributes fixed in both eyes' images. The main advantage of these stimuli is that they enable us to decorrelate the effects of eye competition and percept competition in binocular rivalry. The data show that colour is the most powerful attribute in grouping, and that combinations are stronger than single attributes. Overall, the results indicate that similarity in low-level attributes can drive interocular grouping, and that binocular rivalry follows complex rules of perceptual organisation that cannot be accounted for by eye suppression alone.


2006 ◽  
Vol 76 (1) ◽  
pp. 28-33 ◽  
Author(s):  
Yukari Egashira ◽  
Shin Nagaki ◽  
Hiroo Sanada

We investigated the change of tryptophan-niacin metabolism in rats with puromycin aminonucleoside PAN-induced nephrosis, the mechanisms responsible for their change of urinary excretion of nicotinamide and its metabolites, and the role of the kidney in tryptophan-niacin conversion. PAN-treated rats were intraperitoneally injected once with a 1.0% (w/v) solution of PAN at a dose of 100 mg/kg body weight. The collection of 24-hour urine was conducted 8 days after PAN injection. Daily urinary excretion of nicotinamide and its metabolites, liver and blood NAD, and key enzyme activities of tryptophan-niacin metabolism were determined. In PAN-treated rats, the sum of urinary excretion of nicotinamide and its metabolites was significantly lower compared with controls. The kidneyα-amino-β-carboxymuconate-ε-semialdehyde decarboxylase (ACMSD) activity in the PAN-treated group was significantly decreased by 50%, compared with the control group. Although kidney ACMSD activity was reduced, the conversion of tryptophan to niacin tended to be lower in the PAN-treated rats. A decrease in urinary excretion of niacin and the conversion of tryptophan to niacin in nephrotic rats may contribute to a low level of blood tryptophan. The role of kidney ACMSD activity may be minimal concerning tryptophan-niacin conversion under this experimental condition.


1983 ◽  
Vol 28 (1) ◽  
pp. 79-79
Author(s):  
Claire B. Ernhart

Author(s):  
Raymond F. Genovese ◽  
◽  
Sara J. Shippee ◽  
Jessica Bonnell ◽  
Bernard J. Benton ◽  
...  

1992 ◽  
Author(s):  
Kathy McCloskey ◽  
William B. Albery ◽  
Greg Zehner ◽  
Stephen D. Bolia
Keyword(s):  

1969 ◽  
Author(s):  
Paul Ries ◽  
Edward Pomeroy
Keyword(s):  

Sign in / Sign up

Export Citation Format

Share Document