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Hirata, Yutaka. "Neural signal processing for dynamic visual stabilization." Brain & Neural Networks 11, no. 4 (2004): 176–92. http://dx.doi.org/10.3902/jnns.11.176.
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Nittrouer, Susan, and Joanna H. Lowenstein. "Beyond Recognition: Visual Contributions to Verbal Working Memory." Journal of Speech, Language, and Hearing Research 65, no. 1 (January 12, 2022): 253–73. http://dx.doi.org/10.1044/2021_jslhr-21-00177.
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Purpose: It is well recognized that adding the visual to the acoustic speech signal improves recognition when the acoustic signal is degraded, but how that visual signal affects postrecognition processes is not so well understood. This study was designed to further elucidate the relationships among auditory and visual codes in working memory, a postrecognition process. Design: In a main experiment, 80 young adults with normal hearing were tested using an immediate serial recall paradigm. Three types of signals were presented (unprocessed speech, vocoded speech, and environmental sounds) in three conditions (audio-only, audio–video with dynamic visual signals, and audio–picture with static visual signals). Three dependent measures were analyzed: (a) magnitude of the recency effect, (b) overall recall accuracy, and (c) response times, to assess cognitive effort. In a follow-up experiment, 30 young adults with normal hearing were tested largely using the same procedures, but with a slight change in order of stimulus presentation. Results: The main experiment produced three major findings: (a) unprocessed speech evoked a recency effect of consistent magnitude across conditions; vocoded speech evoked a recency effect of similar magnitude to unprocessed speech only with dynamic visual (lipread) signals; environmental sounds never showed a recency effect. (b) Dynamic and static visual signals enhanced overall recall accuracy to a similar extent, and this enhancement was greater for vocoded speech and environmental sounds than for unprocessed speech. (c) All visual signals reduced cognitive load, except for dynamic visual signals with environmental sounds. The follow-up experiment revealed that dynamic visual (lipread) signals exerted their effect on the vocoded stimuli by enhancing phonological quality. Conclusions: Acoustic and visual signals can combine to enhance working memory operations, but the source of these effects differs for phonological and nonphonological signals. Nonetheless, visual information can support better postrecognition processes for patients with hearing loss.
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Lajoie, Guillaume, and Lai-Sang Young. "Dynamic Signal Tracking in a Simple V1 Spiking Model." Neural Computation 28, no. 9 (September 2016): 1985–2010. http://dx.doi.org/10.1162/neco_a_00868.
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This work is part of an effort to understand the neural basis for our visual system’s ability, or failure, to accurately track moving visual signals. We consider here a ring model of spiking neurons, intended as a simplified computational model of a single hypercolumn of the primary visual cortex of primates. Signals that consist of edges with time-varying orientations localized in space are considered. Our model is calibrated to produce spontaneous and driven firing rates roughly consistent with experiments, and our two main findings, for which we offer dynamical explanation on the level of neuronal interactions, are the following. First, we have documented consistent transient overshoots in signal perception following signal switches due to emergent interactions of the E- and I-populations. Second, for continuously moving signals, we have found that accuracy is considerably lower at reversals of orientation than when continuing in the same direction (as when the signal is a rotating bar). To measure performance, we use two metrics, called fidelity and reliability, to compare signals reconstructed by the system to the ones presented and assess trial-to-trial variability. We propose that the same population mechanisms responsible for orientation selectivity also impose constraints on dynamic signal tracking that manifest in perception failures consistent with psychophysical observations.
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Cezário, Rodrigo Roucourt, Vinicius Marques Lopez, Stanislav Gorb, and Rhainer Guillermo-Ferreira. "Dynamic iridescent signals of male copperwing damselflies coupled with wing-clapping displays: the perspective of different receivers." Biological Journal of the Linnean Society 134, no. 1 (June 2, 2021): 229–39. http://dx.doi.org/10.1093/biolinnean/blab068.
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Abstract Dynamic signals are a widespread phenomenon in several taxa, usually associated with intraspecific communication. In contrast, dynamic iridescent signals are detectable only at specific angles of illumination; hence, the animal can hide the signal to avoid detection when necessary. This structural coloration is mostly dependent on the illumination, the contrast against the background and the vision of the receiver. Complex behavioural displays can be coupled with structural coloration to create dynamic visual signals that enhance these functions. Here, we address whether iridescence of the males of a damselfly that inhabits dark rainforests, Chalcopteryx scintillans, can be considered a dynamic visual signal. We analyse whether coloration is perceived by conspecifics, while reducing detectability to eavesdroppers against three types of backgrounds. Our results suggest that the visual background affects the detectability of male hindwings by different receivers, mostly predators and prey. We discuss whether these results and the angle dependence of colour could indicate a mechanism to avoid unwanted intraspecific interactions or even to lure both predators and prey. We conclude that the main functions of the dynamic iridescent signal are to communicate with conspecifics while hindering the signal for prey, adding evidence of the multifunctionality of structural coloration coupled with behavioural displays in animals.
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Pomante, A., L. P. J. Selen, and W. P. Medendorp. "Perception of the dynamic visual vertical during sinusoidal linear motion." Journal of Neurophysiology 118, no. 4 (October 1, 2017): 2499–506. http://dx.doi.org/10.1152/jn.00439.2017.
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The vestibular system provides information for spatial orientation. However, this information is ambiguous: because the otoliths sense the gravitoinertial force, they cannot distinguish gravitational and inertial components. As a consequence, prolonged linear acceleration of the head can be interpreted as tilt, referred to as the somatogravic effect. Previous modeling work suggests that the brain disambiguates the otolith signal according to the rules of Bayesian inference, combining noisy canal cues with the a priori assumption that prolonged linear accelerations are unlikely. Within this modeling framework the noise of the vestibular signals affects the dynamic characteristics of the tilt percept during linear whole-body motion. To test this prediction, we devised a novel paradigm to psychometrically characterize the dynamic visual vertical—as a proxy for the tilt percept—during passive sinusoidal linear motion along the interaural axis (0.33 Hz motion frequency, 1.75 m/s2peak acceleration, 80 cm displacement). While subjects ( n=10) kept fixation on a central body-fixed light, a line was briefly flashed (5 ms) at different phases of the motion, the orientation of which had to be judged relative to gravity. Consistent with the model’s prediction, subjects showed a phase-dependent modulation of the dynamic visual vertical, with a subject-specific phase shift with respect to the imposed acceleration signal. The magnitude of this modulation was smaller than predicted, suggesting a contribution of nonvestibular signals to the dynamic visual vertical. Despite their dampening effect, our findings may point to a link between the noise components in the vestibular system and the characteristics of dynamic visual vertical.NEW & NOTEWORTHY A fundamental question in neuroscience is how the brain processes vestibular signals to infer the orientation of the body and objects in space. We show that, under sinusoidal linear motion, systematic error patterns appear in the disambiguation of linear acceleration and spatial orientation. We discuss the dynamics of these illusory percepts in terms of a dynamic Bayesian model that combines uncertainty in the vestibular signals with priors based on the natural statistics of head motion.
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Gielen, CCAM, and JAM van Gisbergen. "The Visual Guidance of Saccades and Fast Aiming Movements." Physiology 5, no. 2 (April 1, 1990): 58–63. http://dx.doi.org/10.1152/physiologyonline.1990.5.2.58.
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Sensory signals are used to create an internal representation of the environment. There is good evidence that the same internal representation of target position in space is shared by different motor systems. A central problem is how the command signal is transformed from a spatial code at the sensory side into a dynamic activation signal appropriately matched to the properties of the effector system.
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J. B. Meyers, S. E. Prussia, and C. J. Karwoski. "Signal Detection Theory for Optimizing Dynamic Visual Inspection Performance." Applied Engineering in Agriculture 6, no. 4 (1990): 412–17. http://dx.doi.org/10.13031/2013.26406.
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López, María T., Antonio Fernández-Caballero, Miguel A. Fernández, José Mira, and Ana E. Delgado. "Visual surveillance by dynamic visual attention method." Pattern Recognition 39, no. 11 (November 2006): 2194–211. http://dx.doi.org/10.1016/j.patcog.2006.04.018.
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Ligon, Russell A., and Kevin J. McGraw. "Social costs enforce honesty of a dynamic signal of motivation." Proceedings of the Royal Society B: Biological Sciences 283, no. 1841 (October 26, 2016): 20161873. http://dx.doi.org/10.1098/rspb.2016.1873.
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Understanding the processes that promote signal reliability may provide important insights into the evolution of diverse signalling strategies among species. The signals that animals use to communicate must comprise mechanisms that prohibit or punish dishonesty, and social costs of dishonesty have been demonstrated for several fixed morphological signals (e.g. colour badges of birds and wasps). The costs maintaining the honesty of dynamic signals, which are more flexible and potentially cheatable, are unknown. Using an experimental manipulation of the dynamic visual signals used by male veiled chameleons ( Chamaeleo calyptratus ) during aggressive interactions, we tested the idea that the honesty of rapid colour change signals is maintained by social costs. Our results reveal that social costs are an important mechanism maintaining the honesty of these dynamic colour signals—‘dishonest’ chameleons whose experimentally manipulated coloration was incongruent with their contest behaviour received more physical aggression than ‘honest’ individuals. This is the first demonstration, to the best our knowledge, that the honesty of a dynamic signal of motivation—physiological colour change—can be maintained by the social costliness of dishonesty. Behavioural responses of signal receivers, irrespective of any specific detection mechanisms, therefore prevent chameleon cheaters from prospering.
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Soundirarajan, Mirra, Mohammad Hossein Babini, Sue Sim, Visvamba Nathan, and Hamidreza Namazi. "Decoding of the Relationship between Brain and Facial Muscle Activities in Response to Dynamic Visual Stimuli." Fluctuation and Noise Letters 19, no. 04 (June 23, 2020): 2050041. http://dx.doi.org/10.1142/s0219477520500418.
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In this research, for the first time, we analyze the relationship between facial muscles and brain activities when human receives different dynamic visual stimuli. We present different moving visual stimuli to the subjects and accordingly analyze the complex structure of electromyography (EMG) signal versus the complex structure of electroencephalography (EEG) signal using fractal theory. Based on the obtained results from analysis, presenting the stimulus with greater complexity causes greater change in the complexity of EMG and EEG signals. Statistical analysis also supported the results of analysis and showed that visual stimulus with greater complexity has greater effect on the complexity of EEG and EMG signals. Therefore, we showed the relationship between facial muscles and brain activities in this paper. The method of analysis in this research can be further employed to investigate the relationship between other human organs’ activities and brain activity.
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Jiandong, Zhao, and Ma Shuo. "Dynamic Visual Performance of LED with Different Color Temperature." International Journal of Signal Processing, Image Processing and Pattern Recognition 9, no. 6 (June 30, 2016): 437–46. http://dx.doi.org/10.14257/ijsip.2016.9.6.38.
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van de Ven, Vincent, Bert Jans, Rainer Goebel, and Peter De Weerd. "Early Human Visual Cortex Encodes Surface Brightness Induced by Dynamic Context." Journal of Cognitive Neuroscience 24, no. 2 (February 2012): 367–77. http://dx.doi.org/10.1162/jocn_a_00126.
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Visual scene perception owes greatly to surface features such as color and brightness. Yet, early visual cortical areas predominantly encode surface boundaries rather than surface interiors. Whether human early visual cortex may nevertheless carry a small signal relevant for surface perception is a topic of debate. We induced brightness changes in a physically constant surface by temporally modulating the luminance of surrounding surfaces in seven human participants. We found that fMRI activity in the V2 representation of the constant surface was in antiphase to luminance changes of surrounding surfaces (i.e., activity was in-phase with perceived brightness changes). Moreover, the amplitude of the antiphase fMRI activity in V2 predicted the strength of illusory brightness perception. We interpret our findings as evidence for a surface-related signal in early visual cortex and discuss the neural mechanisms that may underlie that signal in concurrence with its possible interaction with the properties of the fMRI signal.
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Yuan, Shuai, and Lei Guo. "Signal Analysis on Nasal Consonant Based on Nasal Flow Signal." Advanced Materials Research 748 (August 2013): 605–9. http://dx.doi.org/10.4028/www.scientific.net/amr.748.605.
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This paper studies Nasal Initials duration, degree of nasal and formants of Mandarin through Nasal flow meter , using Real-time visual feedback and sonogram reveals nasal interface and the dynamic changes, and sound imposed direction followed by a vowel sound, Reveals the complexity of the nasal articulation, the result shows that the degree of nasal and formant of Monosyllabic are different because different nasal sound acts as initials.
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Grafe, T. Ulmar, and Joremy A. Tony. "Temporal variation in acoustic and visual signalling as a function of stream background noise in the Bornean foot-flagging frog, Staurois parvus." Journal of Ecoacoustics 1, no. 1 (October 26, 2017): 1. http://dx.doi.org/10.22261/jea.x74qe0.
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High background noise can interfere with signal detection and perception. Bornean foot-flagging frogs,Staurois parvus, live along noisy streams and use both acoustic and visual signals to communicate. It remains unclear why acoustic signalling is retained given that visual signalling appears to have clear advantages under these noisy conditions. We hypothesized that temporal dynamics in stream noise have shaped the multimodal communication system inS. parvuswith acoustic signalling at an advantage under more quiet conditions, whereas visual signals will prevail when the noise of rushing water is high after rains. We found that as predicted, maleS. parvusincreased foot flagging and decreased advertisement calling when presented with playbacks of stream noise compared to less noisy pre-playback conditions. Such context-dependent dynamic-selection regimes are recently gaining wider attention and enhance our understanding of the flexibility seen in the use of multimodal signals inS. parvus.
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White, Thomas E. "Jewelled spiders manipulate colour-lure geometry to deceive prey." Biology Letters 13, no. 3 (March 2017): 20170027. http://dx.doi.org/10.1098/rsbl.2017.0027.
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Selection is expected to favour the evolution of efficacy in visual communication. This extends to deceptive systems, and predicts functional links between the structure of visual signals and their behavioural presentation. Work to date has primarily focused on colour, however, thereby understating the multicomponent nature of visual signals. Here I examined the relationship between signal structure, presentation behaviour, and efficacy in the context of colour-based prey luring. I used the polymorphic orb-web spider Gasteracantha fornicata , whose yellow- or white-and-black striped dorsal colours have been broadly implicated in prey attraction. In a manipulative assay, I found that spiders actively control the orientation of their conspicuous banded signals in the web, with a distinct preference for near-diagonal bearings. Further field-based study identified a predictive relationship between pattern orientation and prey interception rates, with a local maximum at the spiders' preferred orientation. There were no morph-specific effects on capture success, either singularly or via an interaction with pattern orientation. These results reveal a dynamic element in a traditionally ‘static’ signalling context, and imply differential functions for chromatic and geometric signal components across visual contexts. More broadly, they underscore how multicomponent signal designs and display behaviours may coevolve to enhance efficacy in visual deception.
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Woo, Kevin. "Signal Competition in Dynamic Visual Environments: Relative Conspicuousness of Social Displays in the Jacky Dragon (Amphibolurus muricatus)." Animal Behavior and Cognition 8, no. 3 (August 3, 2021): 415–45. http://dx.doi.org/10.26451/abc.08.03.07.2021.
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Selection for conspicuousness has been an important force on visual signal design. Although signal efficacy has been extensively studied in acoustic systems, few studies have examined this attribute in dynamic visual signals. Here, I simulated signal competition between Jacky lizards (Amphibolurus muricatus) by presenting the motor patterns (tail-flick, push-up body rock, and slow arm wave) in isolation that are typically used in social communication. Phase 1 used four digital video playback systems to present simultaneous animated display combinations on opposing monitors to a subject that was situated in the middle, and measured orientation towards the monitors and latency to respond. Phase 2 maintained the same set-up and simultaneous display combinations, but tested signal conspicuousness across three levels of visual noise (calm, typical, and windy) simulated by the movement of windblown vegetation in the background. The results suggest that the most conspicuous visual display is the tail-flick, followed by the push-up body rock, and the slow arm wave is the least conspicuous. Moreover, this relationship is robust across the full range of environmental wind conditions. No significant side biases in orientation to displays were detected, which suggested no lateralization in perceptual processes. Jacky lizard display motor patterns which address distinct functional requirements: the tail flick is an ideal alerting component, with high efficacy over a range of signaling conditions. The push-up body rock, which is used only in aggressive displays, has a more restricted range, and the submissive slow arm wave is likely designed to appease nearby dominant males.
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Hamner, J. W., and J. Andrew Taylor. "Automated quantification of sympathetic beat-by-beat activity, independent of signal quality." Journal of Applied Physiology 91, no. 3 (September 1, 2001): 1199–206. http://dx.doi.org/10.1152/jappl.2001.91.3.1199.
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Sympathetic nerve activity (SNA) can provide critical information on cardiovascular regulation; however, in a typical laboratory setting, adequate recordings require assiduous effort, and otherwise high-quality recordings may be clouded by frequent baseline shifts, noise spikes, and muscle twitches. Visually analyzing this type of signal can be a tedious and subjective evaluation, whereas objective analysis through signal averaging is impossible. We propose a new automated technique to identify bursts through objective detection criteria, eliminating artifacts and preserving a beat-by-beat SNA signal for a variety of subsequent analyses. The technique was evaluated during both steady-state conditions (17 subjects) and dynamic changes with rapid vasoactive drug infusion (14 recordings from 5 subjects) on SNA signals of widely varied quality. Automated measures of SNA were highly correlated to visual measures of steady-state activity ( r = 0.903, P < 0.001), dynamic relation measures ( r= 0.987, P < 0.001), and measures of burst-by-burst variability ( r = 0.929, P < 0.001). This automated sympathetic neurogram analysis provides a viable alternative to tedious and subjective visual analyses while maximizing the usability of noisy nerve tracings.
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Yeasin, M., and S. Chaudhuri. "Visual understanding of dynamic hand gestures." Pattern Recognition 33, no. 11 (November 2000): 1805–17. http://dx.doi.org/10.1016/s0031-3203(99)00175-2.
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How, Martin J., Jochen Zeil, and Jan M. Hemmi. "Variability of a dynamic visual signal: the fiddler crab claw-waving display." Journal of Comparative Physiology A 195, no. 1 (November 12, 2008): 55–67. http://dx.doi.org/10.1007/s00359-008-0382-7.
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Krebs, Julia, Evie Malaia, Ronnie B. Wilbur, and Dietmar Roehm. "EEG analysis based on dynamic visual stimuli." Hrvatska revija za rehabilitacijska istraživanja 58, Special Issue (October 12, 2022): 245–66. http://dx.doi.org/10.31299/hrri.58.si.13.
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This paper reviews best practices for experimental design and analysis for sign language research using neurophysiological methods, such as electroencephalography (EEG) and other methods with high temporal resolution, as well as identifies methodological challenges in neurophysiological research on natural sign language processing. In particular, we outline the considerations for generating linguistically and physically well-controlled stimuli accounting for 1) the layering of manual and non-manual information at different timescales, 2) possible unknown linguistic and non-linguistic visual cues that can affect processing, 3) variability across linguistic stimuli, and 4) predictive processing. Two specific concerns with regard to the analysis and interpretation of observed event related potential (ERP) effects for dynamic stimuli are discussed in detail. First, we discuss the “trigger/effect assignment problem”, which describes the difficulty of determining the time point for calculating ERPs. This issue is related to the problem of determining the onset of a critical sign (i.e., stimulus onset time), and the lack of clarity as to how the border between lexical (sign) and transitional movement (motion trajectory between individual signs) should be defined. Second, we discuss possible differences in the dynamics within signing that might influence ERP patterns and should be controlled for when creating natural sign language material for ERP studies. In addition, we outline alternative approaches to EEG data analyses for natural signing stimuli, such as the timestamping of continuous EEG with trigger markers for each potentially relevant cue in dynamic stimuli. Throughout the discussion, we present empirical evidence for the need to account for dynamic, multi-channel, and multi-timescale visual signal that characterizes sign languages in order to ensure the ecological validity of neurophysiological research in sign languages.
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Nikolaou, F., C. Orphanidou, P. Papakyriakou, K. Murphy, R. G. Wise, and G. D. Mitsis. "Spontaneous physiological variability modulates dynamic functional connectivity in resting-state functional magnetic resonance imaging." Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences 374, no. 2067 (May 13, 2016): 20150183. http://dx.doi.org/10.1098/rsta.2015.0183.
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It is well known that the blood oxygen level-dependent (BOLD) signal measured by functional magnetic resonance imaging (fMRI) is influenced—in addition to neuronal activity—by fluctuations in physiological signals, including arterial CO 2 , respiration and heart rate/heart rate variability (HR/HRV). Even spontaneous fluctuations of the aforementioned physiological signals have been shown to influence the BOLD fMRI signal in a regionally specific manner. Related to this, estimates of functional connectivity between different brain regions, performed when the subject is at rest, may be confounded by the effects of physiological signal fluctuations. Moreover, resting functional connectivity has been shown to vary with respect to time (dynamic functional connectivity), with the sources of this variation not fully elucidated. In this context, we examine the relation between dynamic functional connectivity patterns and the time-varying properties of simultaneously recorded physiological signals (end-tidal CO 2 and HR/HRV) using resting-state fMRI measurements from 12 healthy subjects. The results reveal a modulatory effect of the aforementioned physiological signals on the dynamic resting functional connectivity patterns for a number of resting-state networks (default mode network, somatosensory, visual). By using discrete wavelet decomposition, we also show that these modulation effects are more pronounced in specific frequency bands.
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Moro, Stefania S., and Jennifer K. E. Steeves. "Intact Dynamic Visual Capture in People With One Eye." Multisensory Research 31, no. 7 (2018): 675–88. http://dx.doi.org/10.1163/22134808-20181311.
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Abstract Observing motion in one modality can influence the perceived direction of motion in a second modality (dynamic capture). For example observing a square moving in depth can influence the perception of a sound to increase in loudness. The current study investigates whether people who have lost one eye are susceptible to audiovisual dynamic capture in the depth plane similar to binocular and eye-patched viewing control participants. Partial deprivation of the visual system from the loss of one eye early in life results in changes in the remaining intact senses such as hearing. Linearly expanding or contracting discs were paired with increasing or decreasing tones and participants were asked to indicate the direction of the auditory stimulus. Magnitude of dynamic visual capture was measured in people with one eye compared to eye-patched and binocular viewing controls. People with one eye have the same susceptibility to dynamic visual capture as controls, where they perceived the direction of the auditory signal to be moving in the direction of the incongruent visual signal, despite previously showing a lack of visual dominance for audiovisual cues. This behaviour may be the result of directing attention to the visual modality, their partially deficient sense, in order to gain important information about approaching and receding stimuli which in the former case could be life-threatening. These results contribute to the growing body of research showing that people with one eye display unique accommodations with respect to audiovisual processing that are likely adaptive in each unique sensory situation.
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Hansen, Bruce C., Michelle R. Greene, and David J. Field. "Dynamic Electrode-to-Image (DETI) mapping reveals the human brain’s spatiotemporal code of visual information." PLOS Computational Biology 17, no. 9 (September 27, 2021): e1009456. http://dx.doi.org/10.1371/journal.pcbi.1009456.
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A number of neuroimaging techniques have been employed to understand how visual information is transformed along the visual pathway. Although each technique has spatial and temporal limitations, they can each provide important insights into the visual code. While the BOLD signal of fMRI can be quite informative, the visual code is not static and this can be obscured by fMRI’s poor temporal resolution. In this study, we leveraged the high temporal resolution of EEG to develop an encoding technique based on the distribution of responses generated by a population of real-world scenes. This approach maps neural signals to each pixel within a given image and reveals location-specific transformations of the visual code, providing a spatiotemporal signature for the image at each electrode. Our analyses of the mapping results revealed that scenes undergo a series of nonuniform transformations that prioritize different spatial frequencies at different regions of scenes over time. This mapping technique offers a potential avenue for future studies to explore how dynamic feedforward and recurrent processes inform and refine high-level representations of our visual world.
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Suder, K., K. Funke, and F. Woergoetter. "Dynamic Spatiotemporal Restructuring of Visual Receptive Fields through Selective Attention: A Model." Perception 26, no. 1_suppl (August 1997): 375. http://dx.doi.org/10.1068/v970246.
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Cells in the lateral geniculate nucleus (LGN) strongly change their behaviour covarying with different EEG states. During sleep and drowsiness (synchronised alpha, delta-wave EEG) short transient responses prevail whereas during a desynchronised ‘alert’ EEG (beta-waves) long-lasting tonic responses are observed. We propose that this is part of a mechanism used to restructure the spatial and temporal characteristics of the receptive fields in LGN and cortex reflecting changing states of selective attention. To this end we present a model of the primary visual pathway using integrate-and-fire neurons to simulate the afferent signal flow (retina, LGN, V1). The model also implements excitatory topographically arranged lateral intracortical and corticofugal connections which act as a positive feedback and trigger spatial winner-takes-all (WTA) mechanisms enhanced by lateral inhibition at both levels. Furthermore, the LGN membrane characteristic can switch from phasic (hyperpolarised) low-threshold Ca2+ bursting mode to tonic (depolarised) signal-transmission mode. Switching is triggered by feedback and amplified by intracellular intrinsic positive-feedback mechanisms in the model LGN. All positive-feedback mechanisms are subject to damping such that they remain ineffective below a certain threshold. Salient stimuli which ‘attract attention’ will push the system above threshold and a self-amplifying process is started which sharpens the cortical receptive fields spatially (by spatial WTA) and drives the winners in the LGN into signal transmission mode (by intrinsic intracellular mechanisms). These results predicted by the model are in accordance with LGN cell behaviour. In addition, the model predicts that cortical receptive fields should be wider during synchronised EEG than during desynchronised EEG.
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Nattkemper, D. "Visual Motion Induces Effector Movement." Perception 26, no. 1_suppl (August 1997): 280. http://dx.doi.org/10.1068/v970334.
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A left-hand response to a left-hand stimulus is faster than a right-hand response to the same stimulus, even when spatial location is irrelevant to the task at hand. The existence of this spatial stimulus-response correspondence effect suggests that spatial properties of actions to be performed can be pre-specified by spatial properties of perceived events, so that actions are induced by perceptual content. If this view is correct, one should be able to show that not only spatial positions of actions can be pre-specified by properties of perceived events, but other features of actions as well. Specifically, I attempt to show that the direction of a to-be-executed movement can be specified by the direction of a moving stimulus. To study this question a variant of the Simon paradigm was developed: subjects were required to monitor a spot-like stimulus moving from left to right or from right to left on a display. At some point in time the spot would change its colour (from white to blue or red) and the subject had to respond differentially to the respective colour. Two aspects of this situation were varied. First, the type of the action-relevant signal was varied: it could either be a dynamic moving signal or a static non-moving one. Second, the type of response was varied: subjects were required to respond to the colour either with a dynamic response (moving a stylus to the left or right) or with a more static response (pressing a button on the left or on the right).
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Kasap, Bahadir, and A. John van Opstal. "Modeling auditory-visual evoked eye-head gaze shifts in dynamic multisteps." Journal of Neurophysiology 119, no. 5 (May 1, 2018): 1795–808. http://dx.doi.org/10.1152/jn.00502.2017.
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In dynamic visual or auditory gaze double-steps, a brief target flash or sound burst is presented in midflight of an ongoing eye-head gaze shift. Behavioral experiments in humans and monkeys have indicated that the subsequent eye and head movements to the target are goal-directed, regardless of stimulus timing, first gaze shift characteristics, and initial conditions. This remarkable behavior requires that the gaze-control system 1) has continuous access to accurate signals about eye-in-head position and ongoing eye-head movements, 2) that it accounts for different internal signal delays, and 3) that it is able to update the retinal ( TE) and head-centric ( TH) target coordinates into appropriate eye-centered and head-centered motor commands on millisecond time scales. As predictive, feedforward remapping of targets cannot account for this behavior, we propose that targets are transformed and stored into a stable reference frame as soon as their sensory information becomes available. We present a computational model, in which recruited cells in the midbrain superior colliculus drive eyes and head to the stored target location through a common dynamic oculocentric gaze-velocity command, which is continuously updated from the stable goal and transformed into appropriate oculocentric and craniocentric motor commands. We describe two equivalent, yet conceptually different, implementations that both account for the complex, but accurate, kinematic behaviors and trajectories of eye-head gaze shifts under a variety of challenging multisensory conditions, such as in dynamic visual-auditory multisteps.
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Li, Peixia, Boyu Chen, Dong Wang, and Huchuan Lu. "Visual tracking by dynamic matching-classification network switching." Pattern Recognition 107 (November 2020): 107419. http://dx.doi.org/10.1016/j.patcog.2020.107419.
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Chubala, Chrissy M., Tyler M. Ensor, Ian Neath, and Aimée M. Surprenant. "Dynamic Visual Noise Does Not Affect Memory for Fonts." Experimental Psychology 67, no. 3 (March 2020): 161–68. http://dx.doi.org/10.1027/1618-3169/a000491.
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Abstract. Dynamic visual noise (DVN) selectively impairs memory for some types of stimuli (e.g., colors, textures, concrete words), but not for others (e.g., matrices, Chinese characters, simple shapes). According to the image definition hypothesis, the key difference is whether the stimulus leads to images that are ill-defined or well-defined. The former will be affected because the addition of noise quickly reduces the usefulness of the image in supplying information about the item's identity. The image definition hypothesis predicts that fonts should lead to ill-defined images and therefore should be affected by DVN, and although three previous studies appear to show this result, they lack a key control condition and report only proportion correct. Two experiments reassessed whether DVN affects memory for fonts, but, unlike the previous studies, both included a static visual noise condition and both were analyzed using signal detection measures. There was no evidence that DVN affected memory for font information, thus disconfirming a prediction of the original version of image definition hypothesis. We suggest a revised version that focuses on redintegration can explain the results.
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Col, Alcebiades Dal, Paola Valdivia, Fabiano Petronetto, Fabio Dias, Claudio T. Silva, and L. Gustavo Nonato. "Wavelet-Based Visual Analysis of Dynamic Networks." IEEE Transactions on Visualization and Computer Graphics 24, no. 8 (August 1, 2018): 2456–69. http://dx.doi.org/10.1109/tvcg.2017.2746080.
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Raffi, Milena, Alessandro Piras, Roberta Calzavara, and Salvatore Squatrito. "Area PEc Neurons Use a Multiphasic Pattern of Activity to Signal the Spatial Properties of Optic Flow." BioMed Research International 2017 (2017): 1–9. http://dx.doi.org/10.1155/2017/6495872.
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The cortical representation of visual perception requires the integration of several-signal processing distributed across many cortical areas, but the neural substrates of such perception are largely unknown. The type of firing pattern exhibited by single neurons is an important indicator of dynamic circuitry within or across cortical areas. Neurons in area PEc are involved in the spatial mapping of the visual field; thus, we sought to analyze the firing pattern of activity of PEc optic flow neurons to shed some light on the cortical processing of visual signals. We quantified the firing activity of 152 optic flow neurons using a spline interpolation function, which allowed determining onset, end, and latency of each neuronal response. We found that many PEc neurons showed multiphasic activity, which is strictly related to the position of the eye and to the position of the focus of expansion (FOE) of the flow field. PEc neurons showed a multiphasic activity comprised of excitatory phases interspersed with inhibitory pauses. This phasic pattern seems to be a very efficient way to signal the spatial location of visual stimuli, given that the same neuron sends different firing patterns according to a specific combination of FOE/eye position.
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Bachmann, Judith C., Fabio Cortesi, Matthew D. Hall, N. Justin Marshall, Walter Salzburger, and Hugo F. Gante. "Real-time social selection maintains honesty of a dynamic visual signal in cooperative fish." Evolution Letters 1, no. 5 (October 25, 2017): 269–78. http://dx.doi.org/10.1002/evl3.24.
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Pinchuk, Pavlo, and Jean-Luc Margot. "A Machine Learning–based Direction-of-origin Filter for the Identification of Radio Frequency Interference in the Search for Technosignatures." Astronomical Journal 163, no. 2 (January 20, 2022): 76. http://dx.doi.org/10.3847/1538-3881/ac426f.
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Abstract Radio frequency interference (RFI) mitigation remains a major challenge in the search for radio technosignatures. Typical mitigation strategies include a direction-of-origin (DoO) filter, where a signal is classified as RFI if it is detected in multiple directions on the sky. These classifications generally rely on estimates of signal properties, such as frequency and frequency drift rate. Convolutional neural networks (CNNs) offer a promising complement to existing filters because they can be trained to analyze dynamic spectra directly, instead of relying on inferred signal properties. In this work, we compiled several data sets consisting of labeled pairs of images of dynamic spectra, and we designed and trained a CNN that can determine whether or not a signal detected in one scan is also present in another scan. This CNN-based DoO filter outperforms both a baseline 2D correlation model and existing DoO filters over a range of metrics, with precision and recall values of 99.15% and 97.81%, respectively. We found that the CNN reduces the number of signals requiring visual inspection after the application of traditional DoO filters by a factor of 6–16 in nominal situations.
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Młynarski, Wiktor, and Gašper Tkačik. "Efficient coding theory of dynamic attentional modulation." PLOS Biology 20, no. 12 (December 21, 2022): e3001889. http://dx.doi.org/10.1371/journal.pbio.3001889.
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Activity of sensory neurons is driven not only by external stimuli but also by feedback signals from higher brain areas. Attention is one particularly important internal signal whose presumed role is to modulate sensory representations such that they only encode information currently relevant to the organism at minimal cost. This hypothesis has, however, not yet been expressed in a normative computational framework. Here, by building on normative principles of probabilistic inference and efficient coding, we developed a model of dynamic population coding in the visual cortex. By continuously adapting the sensory code to changing demands of the perceptual observer, an attention-like modulation emerges. This modulation can dramatically reduce the amount of neural activity without deteriorating the accuracy of task-specific inferences. Our results suggest that a range of seemingly disparate cortical phenomena such as intrinsic gain modulation, attention-related tuning modulation, and response variability could be manifestations of the same underlying principles, which combine efficient sensory coding with optimal probabilistic inference in dynamic environments.
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Meng, Kun, and Fulong Liu. "Structural Design of Handicrafts Based on Dynamic Simulation Technology." Advances in Multimedia 2022 (August 10, 2022): 1–10. http://dx.doi.org/10.1155/2022/7099856.
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In order to improve the effect of handicraft structure design, this study combines the dynamic simulation technology to build a handicraft structure design system and transmits data through dynamic simulation signals to improve the effectiveness of the interactive design of artworks. In order to provide a simpler and faster development process for interactive media applications, this study develops an interactive media art design system with a node-based visual programming model as the core processing logic. The digital Gaussian shaping method based on the programmable logic device can not only realize real-time Gaussian shaping of the nuclear pulse signal but also meet the needs of later function expansion, maintenance, and upgrade of the system. In addition, this study verifies the effectiveness of the handicraft structure design system based on dynamic simulation technology through the analysis of multiple sets of simulation data.
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Liu, Chong, Miao Duan, Zhihao Duan, Aizun Liu, Zhiguo Lu, and Hong Wang. "An SSVEP-based BCI with LEDs visual stimuli using dynamic window CCA algorithm." Biomedical Signal Processing and Control 76 (July 2022): 103727. http://dx.doi.org/10.1016/j.bspc.2022.103727.
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Chen, Shiming, Hao Wang, Hailang Li, Zhongtang Wei, Pengxu Zheng, and Shibin Wei. "On-board Dynamic Measuring of Long-wave Track Irregularity based on Visual Inertial Fusion." Journal of Physics: Conference Series 2396, no. 1 (December 1, 2022): 012036. http://dx.doi.org/10.1088/1742-6596/2396/1/012036.
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Abstract This paper studies an inspection method to measure the long-wave track irregularities using the signals of IMU (Inertial Measurement Unit) and Laser & Camera installed on a bogie, which is implemented in comprehensive inspection trains. To reduce the influence of random noise and vehicle vibration, the mechanical structure is optimized; the spatial-dependent change of the "two-point chord" on the track is observed by high-precision FOC (Fiber Optic Gyroscope) and laser camera components; the angular velocity measurement method is deduced. To eliminate high-frequency attenuation of the signal, a sensor fusion algorithm based on the concept of complementary filters is presented. The angular velocity-based method is also used to measure low spatial frequencies, while the acceleration-based method is used to measure high spatial frequencies. The measurement accuracy of the system is evaluated from two aspects: internal and external coincidence accuracy. The test shows that the repeatability accuracy of the system to alignment and profile of the wavelength of 200 m is 0.5 mm and 0.8 mm, respectively, and the trend item and the line design value maintain good consistency.
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Wang, Jin. "Research on the Multimedia Music Courseware Design Based on Internet Resource." Applied Mechanics and Materials 380-384 (August 2013): 2095–98. http://dx.doi.org/10.4028/www.scientific.net/amm.380-384.2095.
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With the advance of computer information science and technology, multimedia courseware has been widely used in the application and development of teaching practice. The multimedia music courseware has good auditory dynamic guide and vividness. It can produce very good teaching effect in the teaching process. Music lessons belong to audio-visual vocal class teaching, the abstract of course makes music teaching need to develop multimedia dynamic courseware. Music lessons belong to audio-visual vocal class teaching, the abstract of course makes music teaching need to develop multimedia dynamic courseware. According to this, the paper studies the design and development of multimedia music courseware which treats the internet resources as a platform. According to the signal theory of digital audio and spectrum and smart composer of musical notation system software, this paper converts the audio to MIDI format. Then, it processes the audio signal of the data through Fourier audio signal processing model and gets the format which is suitable to the play of multimedia music courseware. Finally, this paper establishes the interaction of multimedia music courseware and Internet resources using Dreamweaver Web development software and achieves Internet access of multimedia music courseware which provides a theoretical reference for the design and development of multimedia music courseware.
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Oh, Minseok, Sergey Velichko, Scott Johnson, Michael Guidash, Hung-Chih Chang, Daniel Tekleab, Bob Gravelle, et al. "Automotive 3.0 µm Pixel High Dynamic Range Sensor with LED Flicker Mitigation." Sensors 20, no. 5 (March 4, 2020): 1390. http://dx.doi.org/10.3390/s20051390.
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We present and discuss parameters of a high dynamic range (HDR) image sensor with LED flicker mitigation (LFM) operating in automotive temperature range. The total SNR (SNR including dark fixed pattern noise), of the sensor is degraded by floating diffusion (FD) dark current (DC) and dark signal non-uniformity (DSNU). We present results of FD DC and DSNU reduction, to provide required SNR versus signal level at temperatures up to 120 °C. Additionally we discuss temperature dependencies of quantum efficiency (QE), sensitivity, color effects, and other pixel parameters for backside illuminated image sensors. Comparing +120 °C junction vs. room temperature, in visual range we measured a few relative percent increase, while in 940 nm band range we measured 1.46x increase in sensitivity. Measured change of sensitivity for visual bands—such as blue, green, and red colors—reflected some impact to captured image color accuracy that created slight image color tint at high temperature. The tint is, however, hard to detect visually and may be removed by auto white balancing and temperature adjusted color correction matrixes.
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Chino, Yuzo M. "Receptive-Field Plasticity in the Adult Visual Cortex: Dynamic Signal Rerouting or Experience-Dependent Plasticity." Seminars in Neuroscience 9, no. 1-2 (1997): 34–46. http://dx.doi.org/10.1006/smns.1997.0104.
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White, Thomas E., and Tanya Latty. "Flies improve the salience of iridescent sexual signals by orienting toward the sun." Behavioral Ecology 31, no. 6 (October 14, 2020): 1401–9. http://dx.doi.org/10.1093/beheco/araa098.
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Abstract Sunlight is the ultimate source of most visual signals. Theory predicts strong selection for its effective use during communication, with functional links between signal designs and display behaviors a likely result. This is particularly true for iridescent structural colors, whose moment-to-moment appearance bears a heightened sensitivity to the position of signalers, receivers, and the sun. Here, we experimentally tested this prediction using Lispe cana, a muscid fly in which males present their structurally colored faces and wings to females during ground-based sexual displays. In field-based assays, we found that males actively bias the orientation of their displays toward the solar azimuth under conditions of full sunlight and do so across the entire day. This bias breaks down, however, when the sun is naturally concealed by heavy cloud or experimentally obscured. Our modeling of the appearance of male signals revealed clear benefits for the salience of male ornaments, with a roughly 4-fold increase in subjective luminance achievable through accurate display orientation. These findings offer fine-scale, causal evidence for the active control of sexual displays to enhance the appearance of iridescent signals. More broadly, they speak to predicted coevolution between dynamic signal designs and presentation behaviors, and support arguments for a richer appreciation of the fluidity of visual communication.
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Chen, Zhihua, Zhenzhu Wang, Bin Sheng, Chao Li, Ruimin Shen, and Ping Li. "Dynamic RGB-to-CMYK conversion using visual contrast optimisation." IET Image Processing 11, no. 7 (July 1, 2017): 539–49. http://dx.doi.org/10.1049/iet-ipr.2016.0989.
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NAMAZI, HAMIDREZA, TIRDAD SEIFI ALA, and HOVAGIM BAKARDJIAN. "DECODING OF STEADY-STATE VISUAL EVOKED POTENTIALS BY FRACTAL ANALYSIS OF THE ELECTROENCEPHALOGRAPHIC (EEG) SIGNAL." Fractals 26, no. 06 (December 2018): 1850092. http://dx.doi.org/10.1142/s0218348x18500925.
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Analysis of the brain response to different types of external stimuli has always been one of the major research areas in behavioral neuroscience. The electroencephalography (EEG) technique combined with different signal analysis approaches has been especially successful in revealing the detailed dynamic properties of the neural response to exogenous stimulation. In this analysis, we evaluated the nonlinear structure of the EEG signal using fractal theory in rest and visual stimulation (checkerboard reversal at 8, 14 and 28[Formula: see text]Hz). Our analysis showed a significant influence of stimulation on the fractal structure of EEG signal. On comparison between different conditions, 14-Hz steady-state visual evoked potentials (SSVEPs), previously shown to trigger an optimal brain response, exhibited the greatest influence on the complexity of the EEG signal. On the other hand, we observed the lowest complexity of EEG signal in the post-stimulation rest period. Statistical analysis confirmed significant differences in the fractal structure of the EEG signal between rest and different stimulation conditions. These findings demonstrate for the first time a direct relationship between the efficiency of brain processing and the complexity of the measured EEG signal, which could be employed for objective assessment and classification in various experimental paradigms.
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Vingerhoets, R. A. A., W. P. Medendorp, and J. A. M. Van Gisbergen. "Body-Tilt and Visual Verticality Perception During Multiple Cycles of Roll Rotation." Journal of Neurophysiology 99, no. 5 (May 2008): 2264–80. http://dx.doi.org/10.1152/jn.00704.2007.
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To assess the effects of degrading canal cues for dynamic spatial orientation in human observers, we tested how judgments about visual-line orientation in space (subjective visual vertical task, SVV) and estimates of instantaneous body tilt (subjective body-tilt task, SBT) develop in the course of three cycles of constant-velocity roll rotation. These abilities were tested across the entire tilt range in separate experiments. For comparison, we also obtained SVV data during static roll tilt. We found that as tilt increased, dynamic SVV responses became strongly biased toward the head pole of the body axis (A-effect), as if body tilt was underestimated. However, on entering the range of near-inverse tilts, SVV responses adopted a bimodal pattern, alternating between A-effects (biased toward head-pole) and E-effects (biased toward feet-pole). Apart from an onset effect, this tilt-dependent pattern of systematic SVV errors repeated itself in subsequent rotation cycles with little sign of worsening performance. Static SVV responses were qualitatively similar and consistent with previous reports but showed smaller A-effects. By contrast, dynamic SBT errors were small and unimodal, indicating that errors in visual-verticality estimates were not caused by errors in body-tilt estimation. We discuss these results in terms of predictions from a canal-otolith interaction model extended with a leaky integrator and an egocentric bias mechanism. We conclude that the egocentric-bias mechanism becomes more manifest during constant velocity roll-rotation and that perceptual errors due to incorrect disambiguation of the otolith signal are small despite the decay of canal signals.
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Pan, Jia-cheng, Dong-ming Han, Fang-zhou Guo, Da-wei Zhou, Nan Cao, Jing-rui He, Ming-liang Xu, and Wei Chen. "RCAnalyzer: visual analytics of rare categories in dynamic networks." Frontiers of Information Technology & Electronic Engineering 21, no. 4 (April 2020): 491–506. http://dx.doi.org/10.1631/fitee.1900310.
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Lu, Zhong-Lin, Xiangrui Li, Bosco S. Tjan, Barbara A. Dosher, and Wilson Chu. "Attention Extracts Signal in External Noise: A BOLD fMRI Study." Journal of Cognitive Neuroscience 23, no. 5 (May 2011): 1148–59. http://dx.doi.org/10.1162/jocn.2010.21511.
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On the basis of results from behavioral studies that spatial attention improves the exclusion of external noise in the target region, we predicted that attending to a spatial region would reduce the impact of external noise on the BOLD response in corresponding cortical areas, seen as reduced BOLD responses in conditions with large amounts of external noise but relatively low signal, and increased dynamic range of the BOLD response to variations in signal contrast. We found that, in the presence of external noise, covert attention reduced the trial-by-trial BOLD response by 15.5–18.9% in low signal contrast conditions in V1. It also increased the BOLD dynamic range in V1, V2, V3, V3A/B, and V4 by a factor of at least three. Overall, covert attention reduced the impact of external noise by about 73–85% in these early visual areas. It also increased the contrast gain by a factor of 2.6–3.8.
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Maya-Vetencourt, José Fernando, and Nicola Origlia. "Visual Cortex Plasticity: A Complex Interplay of Genetic and Environmental Influences." Neural Plasticity 2012 (2012): 1–14. http://dx.doi.org/10.1155/2012/631965.
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The central nervous system architecture is highly dynamic and continuously modified by sensory experience through processes of neuronal plasticity. Plasticity is achieved by a complex interplay of environmental influences and physiological mechanisms that ultimately activate intracellular signal transduction pathways regulating gene expression. In addition to the remarkable variety of transcription factors and their combinatorial interaction at specific gene promoters, epigenetic mechanisms that regulate transcription have emerged as conserved processes by which the nervous system accomplishes the induction of plasticity. Experience-dependent changes of DNA methylation patterns and histone posttranslational modifications are, in fact, recruited as targets of plasticity-associated signal transduction mechanisms. Here, we shall concentrate on structural and functional consequences of early sensory deprivation in the visual system and discuss how intracellular signal transduction pathways associated with experience regulate changes of chromatin structure and gene expression patterns that underlie these plastic phenomena. Recent experimental evidence for mechanisms of cross-modal plasticity following congenital or acquired sensory deprivation both in human and animal models will be considered as well. We shall also review different experimental strategies that can be used to achieve the recovery of sensory functions after long-term deprivation in humans.
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Smout, Cooper A., and Jason B. Mattingley. "Spatial Attention Enhances the Neural Representation of Invisible Signals Embedded in Noise." Journal of Cognitive Neuroscience 30, no. 8 (August 2018): 1119–29. http://dx.doi.org/10.1162/jocn_a_01283.
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Recent evidence suggests that voluntary spatial attention can affect neural processing of visual stimuli that do not enter conscious awareness (i.e., invisible stimuli), supporting the notion that attention and awareness are dissociable processes [Wyart, V., Dehaene, S., & Tallon-Baudry, C. Early dissociation between neural signatures of endogenous spatial attention and perceptual awareness during visual masking. Frontiers in Human Neuroscience, 6, 1–14, 2012; Watanabe, M., Cheng, K., Murayama, Y., Ueno, K., Asamizuya, T., Tanaka, K., et al. Attention but not awareness modulates the BOLD signal in the human V1 during binocular suppression. Science, 334, 829–831, 2011]. To date, however, no study has demonstrated that these effects reflect enhancement of the neural representation of invisible stimuli per se, as opposed to other neural processes not specifically tied to the stimulus in question. In addition, it remains unclear whether spatial attention can modulate neural representations of invisible stimuli in direct competition with highly salient and visible stimuli. Here we developed a novel EEG frequency-tagging paradigm to obtain a continuous readout of human brain activity associated with visible and invisible signals embedded in dynamic noise. Participants ( n = 23) detected occasional contrast changes in one of two flickering image streams on either side of fixation. Each image stream contained a visible or invisible signal embedded in every second noise image, the visibility of which was titrated and checked using a two-interval forced-choice detection task. Steady-state visual-evoked potentials were computed from EEG data at the signal and noise frequencies of interest. Cluster-based permutation analyses revealed significant neural responses to both visible and invisible signals across posterior scalp electrodes. Control analyses revealed that these responses did not reflect a subharmonic response to noise stimuli. In line with previous findings, spatial attention increased the neural representation of visible signals. Crucially, spatial attention also increased the neural representation of invisible signals. As such, the present results replicate and extend previous studies by demonstrating that attention can modulate the neural representation of invisible signals that are in direct competition with highly salient masking stimuli.
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ROMANENKO, Tetiana, and Nataliia RUSINA. "USE OF VISUAL PROGRAMMING LANGUAGE FOR SIMULATION OF DYNAMIC SYSTEMS." HERALD OF KHMELNYTSKYI NATIONAL UNIVERSITY 295, no. 2 (May 2021): 109–15. http://dx.doi.org/10.31891/2307-5732-2021-295-2-109-115.
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The article presents examples of research of typical links of linear systems and construction and study of transient functions, namely: research of influence of parameters of elements of systems of automatic control of its quality. Programs for automatic control are developing rapidly, the main areas of which are related to the optimization of technological processes and robotics. This encourages the introduction into modern production of high-precision digital systems with more extensive use of computer systems. In the simulation process, there is often a need to carefully select and apply real objects to study the quality of automatic control systems. This can be achieved by using a visual programming language for modeling dynamic systems and designing VisSim. The connection of parameters of automatic control systems with indicators of its quality is investigated: by definition of error coefficient; research of influence of a constant time of a forcing link on quality of automatic control systems by the method of compensation of the part in the main inertia of the control object, for the use of the forcing link. As a result, of research graphic dependences of quality of linear systems of automatic control, research of influence of a constant of time of a forcing link on its quality, carrying out identification of the regulator and object of management of systems of automatic control are received. Studies of the process of modeling dynamic systems were visually presented using the visual programming language VisSim. In particular, by creating virtual laboratory stands to study the quality of different modes of automatic control systems in relation to the performance of signal generators and the calculation of the necessary parameters of the study.
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Kim, Jeffrey J., Stacey Parker, Trent Henderson, and James N. Kirby. "Physiological fractals: visual and statistical evidence across timescales and experimental states." Journal of The Royal Society Interface 17, no. 167 (June 2020): 20200334. http://dx.doi.org/10.1098/rsif.2020.0334.
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A marker of engaging in compassion meditation and related processes is an increase in heart-rate variability (HRV), typically interpreted as a marker of parasympathetic nervous system response. While insightful, open questions remain. For example, which timescale is best to examine the effects of meditation and related practices on HRV? Furthermore, how might advanced time-series analyses––such as stationarity––be able to examine dynamic changes in the mean and variance of the HRV signal across time? Here we apply such methods to previously published data, which measured HRV pre- and post- a two-week compassionate mind training (CMT) intervention. Inspection of these data reveals that a visualization of HRV correlations across resting and compassion meditation states, pre- and post-two-week training, is retained across numerous recording timescales. Here, the fractal-like nature of our data indicates that the accuracy of representing HRV data can exist across timescales, albeit with greater or lesser granularity. Interestingly, inspection of the HRV signal at Time 2 compassion meditation versus Time 1 revealed a more highly correlated (i.e. potentially more stable) signal. We followed up these results with tests of stationarity, which revealed Time 2 had a less stochastic (variable) signal than Time 1, and a measure of distance in the time series, which showed that Time 2 had less of an average difference between rest and meditation than at Time 1. Our results provide novel assessment of visual and statistical markers of HRV change across distinct experimental states.
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Upadhyaya, Prashant, Omar Farooq, M. R. Abidi, and Priyanka Varshney. "Comparative Study of Visual Feature for Bimodal Hindi Speech Recognition." Archives of Acoustics 40, no. 4 (December 1, 2015): 609–19. http://dx.doi.org/10.1515/aoa-2015-0061.
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Abstract In building speech recognition based applications, robustness to different noisy background condition is an important challenge. In this paper bimodal approach is proposed to improve the robustness of Hindi speech recognition system. Also an importance of different types of visual features is studied for audio visual automatic speech recognition (AVASR) system under diverse noisy audio conditions. Four sets of visual feature based on Two-Dimensional Discrete Cosine Transform feature (2D-DCT), Principal Component Analysis (PCA), Two-Dimensional Discrete Wavelet Transform followed by DCT (2D-DWT- DCT) and Two-Dimensional Discrete Wavelet Transform followed by PCA (2D-DWT-PCA) are reported. The audio features are extracted using Mel Frequency Cepstral coefficients (MFCC) followed by static and dynamic feature. Overall, 48 features, i.e. 39 audio features and 9 visual features are used for measuring the performance of the AVASR system. Also, the performance of the AVASR using noisy speech signal generated by using NOISEX database is evaluated for different Signal to Noise ratio (SNR: 30 dB to −10 dB) using Aligarh Muslim University Audio Visual (AMUAV) Hindi corpus. AMUAV corpus is Hindi continuous speech high quality audio visual databases of Hindi sentences spoken by different subjects.