Spatiotemporal factors influence sound-source segregation in localization behavior

2020 ◽  
Author(s):  
Guus Christian van Bentum ◽  
Marc Mathijs van Wanrooij ◽  
A. John Van Opstal
Keyword(s):  
Temporal Order ◽  
Weighted Average ◽  
Spatial Separation ◽  
Stimulus Location ◽  
Spatial Proximity ◽  
Sound Source Segregation ◽  
Close Spatial Proximity ◽  
Inhibitory Interactions ◽  
Localization Behavior ◽  
Sensorimotor Map

To program a goal-directed response in the presence of acoustic reflections, the audio-motor system should suppress the detection of time-delayed sources. We examined the effects of spatial separation and inter-stimulus delay on the ability of human listeners to localize a pair of broadband sounds in the horizontal plane. Participants indicated how many sounds were heard and where these were perceived by making one or two head-orienting localization responses. Results suggest that perceptual fusion of the two sounds depends on delay and spatial separation. Leading and lagging stimuli in close spatial proximity required longer stimulus delays to be perceptually separated than those further apart. Whenever participants heard one sound, their localization responses for synchronous sounds were oriented to a weighted average of both source locations. For short delays, responses were directed towards the leading stimulus location. Increasing spatial separation enhanced this effect. For longer delays, responses were again directed towards a weighted average. When participants perceived two sounds, the first and the second response were directed to either of the leading and lagging source locations. Perceived locations were interchanged often in their temporal order (in ~40% of trials). We show that the percept of two sounds occurring requires sufficient spatiotemporal separation, after which localization can be performed with high accuracy. We propose that the percept of temporal order of two concurrent sounds results from a different process than localization, and discuss how dynamic lateral excitatory-inhibitory interactions within a spatial sensorimotor map could explain the findings.

The Trajectory Effect in Intermodal Temporal Order Judgments

Perception ◽  
10.1068/p5293 ◽  
2005 ◽  
Vol 34 (3) ◽  
pp. 357-370 ◽  
Author(s):  
James C Craig
Keyword(s):  
Temporal Order ◽  
Temporal Order Judgment ◽  
Spatial Position ◽  
Spatial Proximity ◽  
Temporal Separation ◽  
Tactile Displays ◽  
Tactile Pattern ◽  
Common Framework ◽  
Close Spatial Proximity ◽  
Temporal Order Judgments

Subjects judged which one of two patterns, a visual or a tactile pattern, had been presented first. The visual and tactile displays were placed in close spatial proximity. The patterns appeared to move across their respective displays. Although irrelevant to the temporal order judgment (TOJ), the direction of motion of the patterns—the trajectory—affected the judgments. When the leading pattern was moving towards the trailing pattern (consistent movement), subjects tended to judge it, correctly, as leading. When the leading pattern was moving away from the trailing pattern (inconsistent movement), subjects tended to judge it, incorrectly, as trailing. Changing the spatial position of the arrays such that the pattern trajectories were no longer towards one another eliminated the effect of movement on TOJs. Although there was a substantial difference in performance on consistent and inconsistent trials, there were no differences in subjects' ratings of their performances. The results demonstrate that the trajectory effect can be obtained multimodally. The issues whether the effect of motion alters the perceived temporal separation between the visual and tactile patterns, and whether the visual and tactile patterns are represented by a common framework, are discussed.

scholarly journals Involvement of loop 5 lysine residues and the N-terminal β-hairpin of the ribotoxin hirsutellin A on its insecticidal activity

2016 ◽  
Vol 397 (2) ◽  
pp. 135-145 ◽  
Author(s):  
Miriam Olombrada ◽  
Lucía García-Ortega ◽  
Javier Lacadena ◽  
Mercedes Oñaderra ◽  
José G. Gavilanes ◽  
...  
Keyword(s):  
Active Sites ◽  
Structural Changes ◽  
The Other ◽  
Spatial Proximity ◽  
Ribonucleolytic Activity ◽  
The Family ◽  
Lysine Residues ◽  
Hirsutella Thompsonii ◽  
Close Spatial Proximity ◽  
High Degree

Abstract Ribotoxins are cytotoxic members of the family of fungal extracellular ribonucleases best represented by RNase T1. They share a high degree of sequence identity and a common structural fold, including the geometric arrangement of their active sites. However, ribotoxins are larger, with a well-defined N-terminal β-hairpin, and display longer and positively charged unstructured loops. These structural differences account for their cytotoxic properties. Unexpectedly, the discovery of hirsutellin A (HtA), a ribotoxin produced by the invertebrate pathogen Hirsutella thompsonii, showed how it was possible to accommodate these features into a shorter amino acid sequence. Examination of HtA N-terminal β-hairpin reveals differences in terms of length, charge, and spatial distribution. Consequently, four different HtA mutants were prepared and characterized. One of them was the result of deleting this hairpin [Δ(8-15)] while the other three affected single Lys residues in its close spatial proximity (K115E, K118E, and K123E). The results obtained support the general conclusion that HtA active site would show a high degree of plasticity, being able to accommodate electrostatic and structural changes not suitable for the other previously known larger ribotoxins, as the variants described here only presented small differences in terms of ribonucleolytic activity and cytotoxicity against cultured insect cells.

scholarly journals ‘They Eat Potatoes, I Eat Rice’: Symbolic Boundary Making and Space in Neighbour Relations

2011 ◽  
Vol 16 (4) ◽  
pp. 22-33 ◽  
Author(s):  
Gwen Van Eijk
Keyword(s):  
Personal Information ◽  
Spatial Proximity ◽  
Easy Access ◽  
Symbolic Boundaries ◽  
Personal Privacy ◽  
Social Mixing ◽  
Boundary Making ◽  
Close Spatial Proximity ◽  
Depth Interviews ◽  
Symbolic Boundary

This article examines ‘neighbouring’ as the setting in which cross-category relations develop and symbolic boundaries are constructed. The study is based on thirty in-depth interviews with residents living in a multi-ethnic and a mono-ethnic neighbourhood in Rotterdam, the Netherlands. The findings challenge the hoped-for outcomes of social mixing in neighbourhoods, as well as the view that boundary making is something inherent to multi-ethnic neighbourhoods only. Neighbour relations are often setting-specific (relations are interchangeable, scripted and bounded, and passively maintained), which is relevant for understanding the spatiality of neighbouring and the limited exchange of personal information between neighbours. Because neighbouring involves the balancing of personal privacy and close spatial proximity, the exchange of personal information is limited, while spatial proximity ensures easy access to observable (through seeing, hearing and smelling) categorical markers that signify class, ethnicity, lifestyle, etc. In this way, neighbour interaction reconstructs symbolic boundaries rather than breaking them down.

Ontogeny of spatial relationships and social behaviour in juvenile Richardson's ground squirrels

1981 ◽  
Vol 59 (9) ◽  
pp. 1666-1676 ◽  
Author(s):  
Gail R. Michener
Keyword(s):  
Social Interactions ◽  
Social Behaviour ◽  
Ground Squirrels ◽  
Spatial Proximity ◽  
Family Unit ◽  
Social Patterns ◽  
Rapid Acquisition ◽  
The Family ◽  
Core Areas ◽  
Close Spatial Proximity

The development of spatial and social patterns by juvenile Richardson's ground squirrels, from first emergence from the natal burrow to entry into hibernation, is described. Juveniles enter the aboveground population at [Formula: see text] weeks of age. During the next 4 weeks juveniles remain in close spatial proximity to family members with whom they engage in frequent amicable social interactions. Thereafter, juveniles become increasingly independent from the family unit, establishing their own spatially distinct core areas and exhibiting site-dependent dominance toward nonkin. Typically juveniles remain physically closer to and more amicable with littermates and mother than other conspecifics such that they compose kin clusters, the members of which are agonistic toward members of adjacent kin clusters. Daughters are more likely to continue to reside close to kin as adults than are sons. At 9–10 weeks of age juveniles exhibit the majority of spatial and social patterns characteristic of adults, and at 12 weeks they are behaviourally indistinguishable from adults. Similar rapid acquisition of adult patterns occurs in four other species of ground-dwelling sciurids that are also obligate hibernators and that breed immediately following emergence from their first hibernation.

scholarly journals Adenine DNA methylation, 3D genome organization, and gene expression in the parasiteTrichomonas vaginalis

2020 ◽  
Vol 117 (23) ◽  
pp. 13033-13043
Author(s):  
Ayelen Lizarraga ◽  
Zach Klapholz O’Brown ◽  
Konstantinos Boulias ◽  
Lara Roach ◽  
Eric Lieberman Greer ◽  
...  
Keyword(s):  
Gene Expression ◽  
Dna Methylation ◽  
Trichomonas Vaginalis ◽  
Three Dimensional ◽  
Wide Distribution ◽  
Spatial Proximity ◽  
Regulation Of Transcription ◽  
3D Genome ◽  
Intergenic Regions ◽  
Close Spatial Proximity

Trichomonas vaginalisis a common sexually transmitted parasite that colonizes the human urogenital tract causing infections that range from asymptomatic to highly inflammatory. Recent works have highlighted the importance of histone modifications in the regulation of transcription and parasite pathogenesis. However, the nature of DNA methylation in the parasite remains unexplored. Using a combination of immunological techniques and ultrahigh-performance liquid chromatography (UHPLC), we analyzed the abundance of DNA methylation in strains with differential pathogenicity demonstrating that N6-methyladenine (6mA), and not 5‐methylcytosine (5mC), is the main DNA methylation mark inT. vaginalis. Genome-wide distribution of 6mA reveals that this mark is enriched at intergenic regions, with a preference for certain superfamilies of DNA transposable elements. We show that 6mA inT. vaginalisis associated with silencing when present on genes. Interestingly, bioinformatics analysis revealed the presence of transcriptionally active or repressive intervals flanked by 6mA-enriched regions, and results from chromatin conformation capture (3C) experiments suggest these 6mA flanked regions are in close spatial proximity. These associations were disrupted when parasites were treated with the demethylation activator ascorbic acid. This finding revealed a role for 6mA in modulating three-dimensional (3D) chromatin structure and gene expression in this divergent member of the Excavata.

scholarly journals Social structure and residency in aggregations of male sperm whales

2002 ◽  
Vol 80 (7) ◽  
pp. 1189-1196 ◽  
Author(s):  
Erland Lettevall ◽  
Christoph Richter ◽  
Nathalie Jaquet ◽  
Elizabeth Slooten ◽  
Steve Dawson ◽  
...  
Keyword(s):  
Social Structure ◽  
Social Structures ◽  
Spatial Proximity ◽  
Residence Times ◽  
Physeter Macrocephalus ◽  
Sperm Whales ◽  
Apparent Lack ◽  
Male Sperm ◽  
Close Spatial Proximity

Sperm whales (Physeter macrocephalus) are sexually dimorphic in several respects, including size, latitudinal distribution, and social structure. Females are known to have complex social structures, including long-term bonds, but the social structures of sexually mature or maturing males have received much less attention. Using data from aggregations of males off Norway, Nova Scotia, New Zealand, and the Galápagos Islands, we examined aggregation size, residence times within aggregations, clustering at the surface, and long-term bonds. Results were generally consistent among study areas. The aggregations found in each area contained around 10–30 males at any time, and were usually a few tens of kilometres across. Mean residence times within aggregations ranged from a few days to a few weeks. Close clustering at the surface was rare, but present at each site. There was no evidence for preferred companionship between individuals at any temporal scale in any of the study areas. The rarity of clustering and the apparent lack of long-term relationships amongst male sperm whales contrast strongly with results of studies on females, suggesting that both close spatial proximity at the surface and permanent bonds between individuals may be a consequence of the need for care of the young.

scholarly journals Overlooked runaway feedback in the marine nitrogen cycle: the vicious cycle

2012 ◽  
Vol 9 (7) ◽  
pp. 8905-8930
Author(s):  
A. Landolfi ◽  
H. Dietze ◽  
W. Koeve ◽  
A. Oschlies
Keyword(s):  
Ocean Circulation ◽  
Nitrogen Loss ◽  
Spatial Association ◽  
Circulation Model ◽  
Spatial Proximity ◽  
N Losses ◽  
Sources And Sinks ◽  
Close Spatial Proximity ◽  
Individual Rate ◽  
Apparent Stability

Abstract. The marine nitrogen (N) inventory is controlled by the interplay of nitrogen loss processes, here referred to as denitrification, and nitrogen source processes, primarily nitrogen fixation. The apparent stability of the marine N inventory on time scales longer than the estimated N residence time, suggests some intimate balance between N sinks and sources. Such a balance may be perceived easier to achieve when N sinks and sources occur in close spatial proximity, and some studies have interpreted observational evidence for such a proximity as indication for a stabilizing feedback processes. Using a biogeochemical ocean circulation model, we here show instead that a close spatial association of N2 fixation and denitrification can, in fact, trigger destabilizing feedbacks on the N inventory and, because of stoichiometric constrains, lead to net N losses. Contrary to current notion, a balanced N inventory requires a regional separation of N sources and sinks. This can be brought about by factors that reduce the growth of diazotrophs, such as iron, or by factors that affect the fate of the fixed nitrogen remineralization, such as dissolved organic matter dynamics. In light of our findings we suggest that spatial arrangements of N sinks and sources have to be accounted for in addition to individual rate estimates for reconstructing past, evaluating present and predicting future marine N inventory imbalances.

scholarly journals A theory for polymicrogyria and brain arteriovenous malformations in HHT

Neurology ◽  
2018 ◽  
Vol 92 (1) ◽  
pp. 34-42 ◽  
Author(s):  
Jesse M. Klostranec ◽  
Long Chen ◽  
Shobhit Mathur ◽  
Jamie McDonald ◽  
Marie E. Faughnan ◽  
...  
Keyword(s):  
Arteriovenous Malformations ◽  
Fluid Shear Stress ◽  
Transmembrane Protein ◽  
Dominant Negative ◽  
Spatial Proximity ◽  
Imaging Data ◽  
Fluid Shear ◽  
Brain Avm ◽  
Close Spatial Proximity ◽  
The Brain

Hereditary hemorrhagic telangiectasia (HHT) is generally considered a disorder of endothelial dysfunction, characterized by the development of multiple systemic arteriovenous malformations (AVMs), including within the brain. However, there have recently been a number of reports correlating HHT with malformations of cortical development, of which polymicrogyria is the most common type. Here we present 7 new cases demonstrating polymicrogyria in HHT, 6 of which demonstrate a brain AVM (bAVM) in close spatial proximity, with the aim of providing a common origin for the association. Upon reviewing patient genetics and imaging data and comparing with previously reported findings, we form 2 new conclusions: (1) polymicrogyria in HHT appears exclusively associated with a subset of mutations in the transmembrane protein endoglin that is involved with blood flow–related mechanotransduction signaling during angiogenesis and (2) the polymicrogyria is characteristically unilateral, typically focal, and correlates with vascular regions experiencing low fluid shear stress during corticogenesis in utero. Integrating these with findings in the literature from genetics and molecular biology experiments, we propose a theory suggesting haploinsufficient endoglin mutations, especially those that are dominant-negative, may predispose focal, aberrant hypersprouting angiogenesis during corticogenesis that leads to the production of polymicrogyria. This hypoxic insult may further serve as the revealing trigger for later development of a spatially coincident bAVM. This hypothesis suggests an essential role for endoglin-mediated hemodynamic mechanotransduction in normal corticogenesis.

Structure and specificity of antibody molecules

1975 ◽  
Vol 272 (915) ◽  
pp. 43-51 ◽  
Keyword(s):  
Active Site ◽  
Three Dimensional ◽  
Crystallographic Analysis ◽  
Spatial Proximity ◽  
Three Dimensional Model ◽  
Fab Fragment ◽  
Active Centre ◽  
Myeloma Protein ◽  
Close Spatial Proximity ◽  
Difference Fourier

The structure of the Fab' fragment of a human myeloma protein (IgG1 (λ) New) has been determined by X-ray crystallographic analysis to a nominal resolution of 0.2 nm. Each of the structure subunits corresponding to the variable and to the constant homology regions of the light and heavy polypeptide chains contains two irregular (3-sheets which are roughly parallel to each other and surround a tightly packed interior of hydrophobic side chains. The regions of the hypervariable sequences in the light and heavy chains occur in close spatial proximity at one end of the molecule, defining the active site of IgG New. The role of these hypervariable regions in defining the size and shape of the active site of different immunoglobulins is discussed on the basis of the three-dimensional model of Fab' New. Several ligands that bind to the active centre of IgG New have been used to obtain crystalline ligand-Fab' New complexes which were investigated by difference Fourier maps. These studies are analysed in terms of the biological function and specificity of antibodies.

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