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https://www.readbyqxmd.com/read/28641258/quality-assessment-of-perceptual-crosstalk-on-two-view-auto-stereoscopic-displays
#1
Jongyoo Kim, Taewan Kim, Sanghoon Lee, Alan C Bovik
Crosstalk is one of the most severe factors affecting the perceived quality of stereoscopic 3D (S3D) images. It arises from a leakage of light intensity between multiple views, as in auto-stereoscopic displays. Well-known determinants of crosstalk include the co-location contrast and disparity of the left and right images, which have been dealt with in prior studies. However, when a natural stereo image that contains complex naturalistic spatial characteristics is viewed on an auto-stereoscopic display, other factors may also play an important role in the perception of crosstalk...
June 19, 2017: IEEE Transactions on Image Processing: a Publication of the IEEE Signal Processing Society
https://www.readbyqxmd.com/read/28634461/sensitivity-to-acceleration-in-the-human-early-visual-system
#2
Ryohei Nakayama, Isamu Motoyoshi
It is widely believed that the human visual system is insensitive to acceleration in moving stimuli. This notion is supported by evidence that detection sensitivity for velocity modulation in moving stimuli is a lowpass function of the velocity modulation's temporal frequency. However, the lowpass function might be a mixture of detection by attention-based tracking and low-level mechanisms sensitive to acceleration. To revisit the issue of acceleration perception in relation to attentive tracking, we measured detection sensitivities for velocity modulations at various temporal frequencies (0...
2017: Frontiers in Psychology
https://www.readbyqxmd.com/read/28634446/are-distal-and-proximal-visual-cues-equally-important-during-spatial-learning-in-mice-a-pilot-study-of-overshadowing-in-the-spatial-domain
#3
Marie Hébert, Jan Bulla, Denis Vivien, Véronique Agin
Animals use distal and proximal visual cues to accurately navigate in their environment, with the possibility of the occurrence of associative mechanisms such as cue competition as previously reported in honey-bees, rats, birds and humans. In this pilot study, we investigated one of the most common forms of cue competition, namely the overshadowing effect, between visual landmarks during spatial learning in mice. To this end, C57BL/6J × Sv129 mice were given a two-trial place recognition task in a T-maze, based on a novelty free-choice exploration paradigm previously developed to study spatial memory in rodents...
2017: Frontiers in Behavioral Neuroscience
https://www.readbyqxmd.com/read/28634444/experience-dependency-of-reliance-on-local-visual-and-idiothetic-cues-for-spatial-representations-created-in-the-absence-of-distal-information
#4
Fabian Draht, Sijie Zhang, Abdelrahman Rayan, Fabian Schönfeld, Laurenz Wiskott, Denise Manahan-Vaughan
Spatial encoding in the hippocampus is based on a range of different input sources. To generate spatial representations, reliable sensory cues from the external environment are integrated with idiothetic cues, derived from self-movement, that enable path integration and directional perception. In this study, we examined to what extent idiothetic cues significantly contribute to spatial representations and navigation: we recorded place cells while rodents navigated towards two visually identical chambers in 180° orientation via two different paths in darkness and in the absence of reliable auditory or olfactory cues...
2017: Frontiers in Behavioral Neuroscience
https://www.readbyqxmd.com/read/28634321/a-central-mechanism-enhances-pain-perception-of-noxious-thermal-stimulus-changes
#5
B Petre, P Tetreault, V A Mathur, M W Schurgin, J Y Chiao, L Huang, A V Apkarian
Pain perception temporarily exaggerates abrupt thermal stimulus changes revealing a mechanism for nociceptive temporal contrast enhancement (TCE). Although the mechanism is unknown, a non-linear model with perceptual feedback accurately simulates the phenomenon. Here we test if a mechanism in the central nervous system underlies thermal TCE. Our model successfully predicted an optimal stimulus, incorporating a transient temperature offset (step-up/step-down), with maximal TCE, resulting in psychophysically verified large decrements in pain response ("offset-analgesia"; mean analgesia: 85%, n = 20 subjects)...
June 20, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28633972/the-neural-basis-of-form-and-form-motion-integration-from-static-and-dynamic-translational-glass-patterns-a-rtms-investigation
#6
Andrea Pavan, Filippo Ghin, Rita Donato, Gianluca Campana, George Mather
A long-held view of the visual system is that form and motion are independently analysed. However, there is physiological and psychophysical evidence of early interaction in the processing of form and motion. In this study, we used a combination of Glass patterns (GPs) and repetitive Transcranial Magnetic Stimulation (rTMS) to investigate in human observers the neural mechanisms underlying form-motion integration. GPs consist of randomly distributed dot pairs (dipoles) that induce the percept of an oriented stimulus...
June 17, 2017: NeuroImage
https://www.readbyqxmd.com/read/28632457/the-bevps-a-new-test-battery-to-assess-visual-perceptual-and-spatial-processing-abilities-in-5-14-year-old-children
#7
Emilie Schmetz, Laurence Rousselle, Cécile Ballaz, Jean-Jacques Detraux, Koviljka Barisnikov
This study aims to examine the different levels of visual perceptual object recognition (early, intermediate, and late) defined in Humphreys and Riddoch's model as well as basic visual spatial processing in children using a new test battery (BEVPS). It focuses on the age sensitivity, internal coherence, theoretical validity, and convergent validity of this battery. French-speaking, typically developing children (n = 179; 5 to 14 years) were assessed using 15 new computerized subtests. After selecting the most age-sensitive tasks though ceiling effect and correlation analyses, an exploratory factorial analysis was run with the 12 remaining subtests to examine the BEVPS' theoretical validity...
June 20, 2017: Applied Neuropsychology. Child
https://www.readbyqxmd.com/read/28630450/concurrent-talking-in-immersive-virtual-reality-on-the-dominance-of-visual-speech-cues
#8
Mar Gonzalez-Franco, Antonella Maselli, Dinei Florencio, Nikolai Smolyanskiy, Zhengyou Zhang
Humans are good at selectively listening to specific target conversations, even in the presence of multiple concurrent speakers. In our research, we study how auditory-visual cues modulate this selective listening. We do so by using immersive Virtual Reality technologies with spatialized audio. Exposing 32 participants to an Information Masking Task with concurrent speakers, we find significantly more errors in the decision-making processes triggered by asynchronous audiovisual speech cues. More precisely, the results show that lips on the Target speaker matched to a secondary (Mask) speaker's audio severely increase the participants' comprehension error rates...
June 19, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28628004/visual-field-map-clusters-in-human-frontoparietal-cortex
#9
Wayne E Mackey, Jonathan Winawer, Clayton E Curtis
The visual neurosciences have made enormous progress in recent decades, in part because of the ability to drive visual areas by their sensory inputs, allowing researchers to reliably define visual areas across individuals and across species. Similar strategies for parcellating higher-order cortex have proven elusive. Here, using a novel experimental task and nonlinear population receptive field modeling we map and characterize the topographic organization of several regions in human frontoparietal cortex. We discover representations of both polar angle and eccentricity that are organized into clusters, similar to visual cortex, where multiple gradients of polar angle of the contralateral visual field share a confluent fovea...
June 19, 2017: ELife
https://www.readbyqxmd.com/read/28623390/disturbed-cervical-proprioception-affects-perception-of-spatial-orientation-while-in-motion
#10
Eva-Maj Malmström, Per-Anders Fransson, Terese Jaxmar Bruinen, Semir Facic, Fredrik Tjernström
The proprioceptive, visual and vestibular sensory systems interact to maintain dynamic stability during movement. The relative importance and interplay between these sensory systems is still not fully understood. Increased knowledge about spatial perception and postural orientation would provide better understanding of balance disorders, and their rehabilitation. Displacement of the body in space was recorded in 16 healthy subjects performing a sequence of stepping-in-place tests without any visual or auditory cues...
June 17, 2017: Experimental Brain Research. Experimentelle Hirnforschung. Expérimentation Cérébrale
https://www.readbyqxmd.com/read/28623107/speech-in-noise-perception-in-unilateral-hearing-loss-relation-to-pure-tone-thresholds-and-brainstem-plasticity
#11
Nicolas Vannson, Chris J James, Bernard Fraysse, Boris Lescure, Kuzma Strelnikov, Olivier Deguine, Pascal Barone, Mathieu Marx
We investigated speech recognition in noise in subjects with mild to profound levels of unilateral hearing loss. Thirty-five adults were evaluated using an adaptive signal-to-noise ratio (SNR50) sentence recognition threshold test in three spatial configurations. The results revealed a significant correlation between pure-tone average audiometric thresholds in the poorer ear and SNR thresholds in the two conditions where speech and noise were spatially separated: dichotic - with speech presented to the poorer ear and reverse dichotic - with speech presented to the better ear...
June 13, 2017: Neuropsychologia
https://www.readbyqxmd.com/read/28622700/evidence-for-long-range-spatiotemporal-interactions-in-infant-and-adult-visual-cortex
#12
Anthony M Norcia, Francesca Pei, Peter J Kohler
The development of spatiotemporal interactions giving rise to classical receptive field properties has been well studied in animal models, but little is known about the development of putative nonclassical mechanisms in any species. Here we used visual evoked potentials to study the developmental status of spatiotemporal interactions for stimuli that were biased to engage long-range spatiotemporal integration mechanisms. We compared responses to widely spaced stimuli presented either in temporal succession or at the same time...
June 1, 2017: Journal of Vision
https://www.readbyqxmd.com/read/28619653/on-optimal-spatial-filtering-for-the-detection-of-phase-coupling-in-multivariate-neural-recordings
#13
G Waterstraat, G Curio, V V Nikulin
INTRODUCTION: Neuronal oscillations synchronize processing in the brain over large spatiotemporal scales and thereby facilitate integration of individual functional modules. Up to now, the relation between the phases of neuronal oscillations and behavior or perception has mainly been analyzed in sensor space of multivariate EEG/MEG recordings. However, sensor-space analysis distorts the topographies of the underlying neuronal sources and suffers from low signal-to-noise ratio. Instead, we propose an optimized source reconstruction approach (Phase Coupling Optimization, PCO)...
June 13, 2017: NeuroImage
https://www.readbyqxmd.com/read/28618825/spectral-equalization-in-binaural-signals-represented-by-order-truncated-spherical-harmonics
#14
Zamir Ben-Hur, Fabian Brinkmann, Jonathan Sheaffer, Stefan Weinzierl, Boaz Rafaely
The synthesis of binaural signals from spherical microphone array recordings has been recently proposed. The limited spatial resolution of the reproduced signal due to order-limited reproduction has been previously investigated perceptually, showing spatial perception ramifications, such as poor source localization and limited externalization. Furthermore, this spatial order limitation also has a detrimental effect on the frequency content of the signal and its perceived timbre, due to the rapid roll-off at high frequencies...
June 2017: Journal of the Acoustical Society of America
https://www.readbyqxmd.com/read/28616169/host-sympatry-and-body-size-influence-parasite-straggling-rate-in-a-highly-connected-multihost-multiparasite-system
#15
Jose L Rivera-Parra, Iris I Levin, Kevin P Johnson, Patricia G Parker
Parasite lineages commonly diverge when host lineages diverge. However, when large clades of hosts and parasites are analyzed, some cases suggest host switching as another major diversification mechanism. The first step in host switching is the appearance of a parasite on an atypical host, or "straggling." We analyze the conditions associated with straggling events. We use five species of colonially nesting seabirds from the Galapagos Archipelago and two genera of highly specific ectoparasitic lice to examine host switching...
June 2017: Ecology and Evolution
https://www.readbyqxmd.com/read/28614367/pre-saccadic-perception-separate-time-courses-for-enhancement-and-spatial-pooling-at-the-saccade-target
#16
Antimo Buonocore, Alessio Fracasso, David Melcher
We interact with complex scenes using eye movements to select targets of interest. Studies have shown that the future target of a saccadic eye movement is processed differently by the visual system. A number of effects have been reported, including a benefit for perceptual performance at the target ("enhancement"), reduced influences of backward masking ("un-masking"), reduced crowding ("un-crowding") and spatial compression towards the saccade target. We investigated the time course of these effects by measuring orientation discrimination for targets that were spatially crowded or temporally masked...
2017: PloS One
https://www.readbyqxmd.com/read/28610816/egocentric-distance-perception-and-performance-of-direct-pointing-in-stereoscopic-displays
#17
Chiuhsiang J Lin, Bereket H Woldegiorgis
In this study, the interaction performances and spatial perceptions in stereoscopic environments were investigated. The experiment compared direct user interactions during pointing at a target, which was continuously visible or presented briefly and disappeared, in both stereoscopic and real environments, at three parallax/depth levels. The position data, collected by a motion system, were used to compute accuracy, signed error, movement time, and throughput. The results showed inaccurate egocentric distance judgment in stereoscopic displays and accurate perceptions in the real world...
October 2017: Applied Ergonomics
https://www.readbyqxmd.com/read/28609418/surround-propinquity-and-tonic-accommodation
#18
Tammy Nguyen, Lawrence R Stark
PURPOSE: Previous studies of dark focus have found evidence of a propinquity response, in which subjects accommodate to the perceived distance of their surroundings despite being in absolute darkness. Their distance perception in a lighted room allows a spatial representation to persist within the darkened room. This study sought to establish the significance and magnitude of the propinquity response in a large sample of young adults, and to determine whether the propinquity response can be predicted by a subject's initial dark focus in an unknown dark room...
June 10, 2017: Optometry and Vision Science: Official Publication of the American Academy of Optometry
https://www.readbyqxmd.com/read/28607664/diagnosing-the-periphery-using-the-rey-osterrieth-complex-figure-drawing-test-to-characterize-peripheral-visual-function
#19
Daniel R Coates, Johan Wagemans, Bilge Sayim
Peripheral vision is strongly limited by crowding, the deleterious influence of neighboring stimuli on target perception. Many quantitative aspects of this phenomenon have been characterized, but the specific nature of the perceptual degradation remains elusive. We utilized a drawing technique to probe the phenomenology of peripheral vision, using the Rey-Osterrieth Complex Figure, a standard neuropsychological clinical instrument. The figure was presented at 12° or 6° in the right visual field, with eye tracking to ensure that the figure was only presented when observers maintained stable fixation...
May 2017: I-Perception
https://www.readbyqxmd.com/read/28605738/spatial-neglect-predicts-upper-limb-use-in-the-activities-of-daily-living
#20
Tim Vanbellingen, Beatrice Ottiger, Noortje Maaijwee, Tobias Pflugshaupt, Stephan Bohlhalter, René M Müri, Tobias Nef, Dario Cazzoli, Thomas Nyffeler
BACKGROUND AND PURPOSE: Motor tests performed at stroke onset have been shown to predict the recovery of upper limb motor impairment. Less is known about upper limb recovery at the level of functional activity or of participation and how spatial neglect may influence the integration of the upper limb in the activities of daily living (ADL). Our objective was to investigate whether the initial severity of spatial neglect may predict upper limb use in ADL. METHODS: Eighty-two patients with a right-hemispheric stroke (RHS) were prospectively included in the study...
June 13, 2017: Cerebrovascular Diseases
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