Spatial Organization and Magnitude of Orientation Contrast Interactions in Primate V1

2002 ◽  
Vol 88 (5) ◽  
pp. 2796-2808 ◽  
Author(s):  
H. E. Jones ◽  
W. Wang ◽  
A. M. Sillito

We have explored the spatial organization of orientation contrast effects in primate V1. Our stimuli were either concentric patches of drifting grating of varying orientation and diameter or grating patches displaced in x–y coordinates around a central patch overlying the classical receptive field (CRF). All cells in the sample exhibited response suppression to iso-oriented stimuli exceeding the CRF. Changing the outer stimulus orientation revealed five response patterns: 1) orientation alignment suppression (17% of cells)—a suppressive component tuned to the same orientation as the cell's optimal, 2) orientation contrast facilitation (63%)—responses to orientation contrast stimuli exceeded those to the center stimulus alone, 3) nonorientation specific suppression (3%), 4) mixed general suppression and alignment suppression (14%), and 5) orientation contrast suppression (14%)—cross-oriented stimuli evoked stronger suppression than iso-oriented stimuli. Thus most cells (94%) showed larger responses to orientation contrast stimuli than to iso-oriented stimuli, and over one-half showed orientation contrast facilitation. There appeared to be a spatially structured organization of the zones driving the different response patterns with respect to the CRF. Nonorientation-specific suppression and orientation contrast suppression were predominantly evoked by orientation contrast borders located within the CRF, and orientation contrast facilitation was mainly driven by surround stimuli lying outside the CRF. This led to different response patterns according to border location. Zones driving orientation contrast facilitation were not necessarily contiguous to, nor uniformly distributed around, the CRF. Our data support two processes underlying orientation contrast enhancement effects: a simple variation in the strength of surround suppression drawing on the fact that surround suppression is tuned to the same orientation as the CRF and a second process driven by orientation contrast that enhanced cells' responses to CRF stimulation by either dis-inhibition or orientation contrast facilitation. We suggest these processes may serve to enhance response levels to salient image features such as junctions and corners and may contribute to orientation pop-out.

1992 ◽  
Vol 67 (4) ◽  
pp. 961-980 ◽  
Author(s):  
J. J. Knierim ◽  
D. C. van Essen

1. We recorded responses from neurons in area V1 of the alert macaque monkey to textured patterns modeled after stimuli used in psychophysical experiments of pop-out. Neuronal responses to a single oriented line segment placed within a cell's classical receptive field (CRF) were compared with responses in which the center element was surrounded by rings of elements placed entirely outside the CRF. The orientations of the surround elements either matched the center element, were orthogonal to it, or were random. 2. The addition of the textured surround tended to suppress the response to the center element by an average of 34%. Overall, almost 80% of the 122 cells analyzed in detail were significantly suppressed by at least one of the texture surrounds. 3. Cells tended to respond more strongly to a stimulus in which there was a contrast in orientation between the center and surround than to a stimulus lacking such contrast. The average difference was 9% of the response to the optimally oriented center element alone. For the 32% of the cells showing a statistically significant orientation contrast effect, the average difference was 28%. 4. Both the general suppression and orientation contrast effects originated from surround regions at the ends of the center bar as well as regions along the sides of the center bar. 5. The amount of suppression induced by the texture surround decreased as the density of the texture elements decreased. 6. Both the general suppression and the orientation contrast effects appeared early in the population response to the stimuli. The general suppression effect took approximately 7 ms to develop, whereas the orientation contrast effect took 18-20 ms to develop. 7. These results are consistent with a possible functional role of V1 cells in the mediation of perceptual pop-out and in the segregation of texture borders. Possible anatomic substrates of the effects are discussed.


1974 ◽  
Vol 1 (2) ◽  
pp. 185-194 ◽  
Author(s):  
Margaret Donaldson ◽  
James McGarrigle

ABSTRACTStudies of comprehension of the quantifiers all and more are reported. The subjects were children between the ages of three and five. There were two main conditions. In one of these the objects to which the quantifiers related were enclosed in containers which either were or were not filled by the objects. In the other no containers were present. These conditions yielded substantially different response patterns. The relation of the findings to those typically obtained from Piagetian conservation tasks is discussed; and the implications for theories of semantic development are considered.


2021 ◽  
Author(s):  
Yin-Xia Sun ◽  
Zhuang-Zhuang Chen ◽  
Geng Guo ◽  
Ruo-Yu Li ◽  
Ting Zhang ◽  
...  

Based on tetraphenylethylene as the skeleton, two novel salamo-type fluorescent probes (TPES1 = 2-hydroxy-1-naphthaldehyde O-(3-(((-2-hydroxy-5-(1,2,2-triphenylvinyl)benzylidene)amino)oxy)propyl) oxime and TPES2 = bis(2-hydroxy-1-naphthaldehyde O-(3-(((2-hydroxy-5-(1,2,2-triphenylvinyl)benzylidene)amino)oxy)propyl) dioxime) were designed and synthesized. Through the colorimetric and...


2020 ◽  
Vol 8 (1) ◽  
pp. 89-119
Author(s):  
Nathalie Vissers ◽  
Pieter Moors ◽  
Dominique Genin ◽  
Johan Wagemans

Artistic photography is an interesting, but often overlooked, medium within the field of empirical aesthetics. Grounded in an art–science collaboration with art photographer Dominique Genin, this project focused on the relationship between the complexity of a photograph and its aesthetic appeal (beauty, pleasantness, interest). An artistic series of 24 semi-abstract photographs that play with multiple layers, recognisability vs unrecognizability and complexity was specifically created and selected for the project. A large-scale online study with a broad range of individuals (n = 453, varying in age, gender and art expertise) was set up. Exploratory data-driven analyses revealed two clusters of individuals, who responded differently to the photographs. Despite the semi-abstract nature of the photographs, differences seemed to be driven more consistently by the ‘content’ of the photograph than by its complexity levels. No consistent differences were found between clusters in age, gender or art expertise. Together, these results highlight the importance of exploratory, data-driven work in empirical aesthetics to complement and nuance findings from hypotheses-driven studies, as they allow to go further than a priori assumptions, to explore underlying clusters of participants with different response patterns, and to point towards new venues for future research. Data and code for the analyses reported in this article can be found at https://osf.io/2fws6/.


Genes ◽  
2020 ◽  
Vol 11 (10) ◽  
pp. 1156
Author(s):  
Jing Cheng ◽  
Keji Yu ◽  
Mingyue Zhang ◽  
Ying Shi ◽  
Changqing Duan ◽  
...  

To investigate the effect of light intensity on flavonoid biosynthesis, grapevine calluses were subjected to high light (HL, 250 μmol m−2 s−1) and dark (0 μmol m−2 s−1) in comparison to 125 μmol m−2 s−1 under controlled conditions (NL). The alteration of flavonoid profiles was determined and was integrated with RNA sequencing (RNA-seq)-based transcriptional changes of the flavonoid pathway genes. Results revealed that dark conditions inhibited flavonoid biosynthesis. Increasing light intensity affected flavonoids differently—the concentrations of flavonols and anthocyanins as well as the expressions of corresponding genes were less affected, whereas flavan-3-ol concentrations were predominantly increased, which caused enhanced trans-flavan-3-ol concentrations. Moreover, genes encoding leucoanthocyanidin reductase (LAR) exhibited different response patterns to light intensity changes—VviLAR1 expression increased with an increased light intensity, whereas VviLAR2 expression was insensitive. We further confirmed that the known transcription factors (TFs) involved in regulating flavan-3-ol biosynthesis utilized VviLAR1 as a target gene in grapevine calluses. In addition, VviLAR1 promoter activity was more sensitive to light intensity changes than that of VviLAR2 as determined using a transgenic Arabidopsis leaf system. These results suggested that light intensity had the most prominent effect on trans-flavan-3-ols in grapevine calluses and demonstrated that the two LAR genes had different response patterns to light intensity changes.


1979 ◽  
Vol 25 (5) ◽  
pp. 419-424 ◽  
Author(s):  
Donald R. Goodenough ◽  
Philip K. Oltman ◽  
Eric Sigman ◽  
James Rosso ◽  
Herbert Mertz

1971 ◽  
Vol 133 (6) ◽  
pp. 1294-1308 ◽  
Author(s):  
George Senyk ◽  
E. Brady Williams ◽  
Danute E. Nitecki ◽  
Joel W. Goodman

Bovine glucagon, a polypeptide of 29 amino acids, was immunogenic in guinea pigs. The immunologic determinants of glucagon were investigated using isolated tryptic peptides of the hormone. Antibodies from virtually all of more than two dozen animals had specificity primarily for the amino-terminal heptadecapeptide (NM) and showed little or no binding with the carboxy-terminal undeca- and dodecapeptides (C). The smallest synthetic peptide of a series initiated at residue 16 which measurably bound antibody comprised residues 5–16 of glucagon. In cellular immune assays, both NM and C elicited delayed cutaneous reactions and inhibited the migration of peritoneal cells from immune animals. However, only intact glucagon and its C fragment stimulated lymphoid cells to synthesize DNA. While glucagon was somewhat more active than C, the addition of NM to C did not enhance its transforming activity. The smallest synthetic carboxy-terminal peptide with discernible transforming activity comprised residues 19–29 of glucagon. In both native and synthetic C peptide preparations, the undecapeptide was generally more active than the dodecapeptide, although cells from different animals gave different response patterns. The difference between the two is the presence of arginine at the amino-terminus of the peptide chain. Thus, the recognition specificity of populations of antigen-reactive cells from different animals displays a variation which is at least superficially analogous to that of populations of antibody molecules. In limited experiments using NM and C peptides as immunogens, neither gave rise to delayed hypersensitivity or to glucagon-binding circulating antibody, following a regimen which invariably provoked these responses when glucagon itself served as the immunogen. These results indicate that glucagon was cleaved by trypsin along functional lines into two parts, one of which housed the major antigenic determinant and the other of which carried the major immunogenic determinant, and they are highly compatible with a two-cell mechanism of immune induction. An apparent dissociation between the capacity to provoke delayed hypersensitivity reactions and to transform antigen-reactive cells in culture was observed.


Ecosystems ◽  
2016 ◽  
Vol 20 (5) ◽  
pp. 904-916 ◽  
Author(s):  
Deping Zhai ◽  
Wanyu Jin ◽  
Junjiong Shao ◽  
Yanghui He ◽  
Guodong Zhang ◽  
...  

2011 ◽  
Vol 41 (3) ◽  
pp. 437-449 ◽  
Author(s):  
Sigrun Aune ◽  
Annika Hofgaard ◽  
Lars Söderström

High-latitude regions are experiencing substantial climate change, and the forest–tundra transition is assumed to sensitively track these changes through advancing treeline and increased tundra encroachment. However, herbivores may influence these responses. The present study addresses, through analyses of age structures, growth characteristics, and climate correspondence, how mountain birch (Betula pubescens Ehrh. ssp. czerepanovii (Orlova) Hämet-Ahti) treelines and sapling cohorts beyond the treeline have responded to the last decade’s warming in six North European subarctic areas with different climate and grazing characters. The results show different response patterns among areas representing advancing, stationary, and possibly retreating treelines. Recruitment was abundant over the last decades in all areas except one, with predominantly arctic conditions, where both tree and sapling cohorts were old. Areas with high annual precipitation show advancing birch populations characterized by young individuals and partly overlapping tree and sapling age distributions. Areas in reindeer herding districts show stationary or retreating birch populations characterized by nonoverlapping age distributions and low sapling survival. Recruitment patterns beyond the treeline generally corresponded with non-growing-season climate variables, mainly precipitation, indicating the importance of a protecting snow cover. The results highlight the important interplay between abiotic and biotic control over tundra encroachment and treeline dynamics and the importance of multisite studies when addressing responses to warming.


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