Prolongation of a short stimulus‐to‐atrial interval during para‐Hisian pacing: What is the mechanism?

2021 ◽  
Author(s):  
Taihei Itoh ◽  
Masaomi Kimura ◽  
Yuichi Toyama ◽  
Shogo Hamaura ◽  
Hirofumi Tomita
Keyword(s):  
Short Stimulus

scholarly journals Development of Memory Structures for Homographs Using Pathfinder Network Representations

2003 ◽  
Vol 6 (1) ◽  
pp. 12-27 ◽  
Author(s):  
Francisco Nievas ◽  
Fernando Justicia
Keyword(s):  
Semantic Priming ◽  
Cohort Effect ◽  
Stimulus Onset ◽  
Developmental Differences ◽  
Memory Structure ◽  
Short Stimulus Onset Asynchrony ◽  
Semantic Priming Effect ◽  
Short Stimulus ◽  
Pathfinder Network ◽  
Memory Structures

Some studies with children have shown that there is no semantic priming at short stimulus onset asynchrony (SOA) in lexical decision and naming tasks for homographs. The predictions of spreading activation theories might explain this missing effect. There may be differences in children's and adults' memory structures. We have explored this hypothesis. The development of memory structure representations for homographs was measured by a Pathfinder algorithm. In Experiment 1, the three dependent variables were: the number of links in the network, closeness measures (C), and distances between nodes. Results revealed developmental differences in network structure representations in adults and children. In Experiment 2, results revealed that these differences were not due to the cohort effect. In Experiment 3, the relationship between associative strength, as measured by associative norms, and distances, as measured by Pathfinder algorithm, was explored. The results of these three experiments and empirical research from semantic priming experiments show that these differences in memory structure representations could be one of the sources of the missing semantic priming effect in children.

A Computational Model of the Perceived Velocity of Moving Plaids

Perception ◽  
1996 ◽  
Vol 25 (1_suppl) ◽  
pp. 87-87
Author(s):  
I Lamouret ◽  
V Cornilleau-Pérès ◽  
J Droulez
Keyword(s):  
Optic Flow ◽  
Type Ii ◽  
Local Velocity ◽  
Local Motion ◽  
Aperture Problem ◽  
Tilted Line ◽  
Short Stimulus ◽  
Detection Mechanisms ◽  
Perceived Velocity ◽  
Gradient Models

Local motion detection mechanisms generally lead to one component of the optic flow becoming indeterminate. One way to solve this ‘aperture problem’ is to compute the optic flow which minimises some smoothing constraint. With iterative schemes the computed velocity array is suboptimal relative to the constraint until the process has converged. Under the original assumption that the iteration rate is sufficiently low to allow the perception of suboptimal flows at short stimulus durations, iterative gradient models give an accurate description of biases in the perception of tilted line velocity. We examine whether this approach can be applied to moving sinusoidal plaids. Our simulations are in agreement with a number of psychophysical results on both speed and direction perception. In particular we show that the effect of stimulus duration on the perceived direction of type II plaids [Yo and Wilson, 1992 Vision Research32(1)] can be accounted for without recourse to second-order mechanisms. The effects of contrast and component directions on the evolution rate of this bias are well reproduced. The model also successfully describes the effect of spatial frequency, and data obtained with gratings. These results suggest that iterative gradient schemes can model the dynamics of interactions between local velocity detectors, as revealed by psychophysical experiments with lines and plaids.

Stimulus-Dependent Assembly Formation of Oscillatory Responses: I. Synchronization

1991 ◽  
Vol 3 (2) ◽  
pp. 155-166 ◽  
Author(s):  
Peter König ◽  
Thomas B. Schillen
Keyword(s):  
Nonlinear Oscillator ◽  
Experimental Situation ◽  
Temporal Correlation ◽  
Temporal Coding ◽  
Two Dimensional ◽  
Neuronal Populations ◽  
Cortical Areas ◽  
Short Stimulus ◽  
Object Features ◽  
The Brain

Current concepts in neurobiology of vision assume that local object features are represented by distributed neuronal populations in the brain. Such representations can lead to ambiguities if several distinct objects are simultaneously present in the visual field. Temporal characteristics of the neuronal activity have been proposed as a possible solution to this problem and have been found in various cortical areas. In this paper we introduce a delayed nonlinear oscillator to investigate temporal coding in neuronal networks. We show synchronization within two-dimensional layers consisting of oscillatory elements coupled by excitatory delay connections. The observed correlation length is large compared to coupling length. Following the experimental situation, we then demonstrate the response of such layers to two short stimulus bars of varying gap distance. Coherency of stimuli is reflected by the temporal correlation of the responses, which closely resembles the experimental observations.

scholarly journals Discriminating the direction of second-order motion at short stimulus durations

1993 ◽  
Vol 33 (13) ◽  
pp. 1785-1794 ◽  
Author(s):  
Andrew M. Derrington ◽  
David R. Badcock ◽  
G. Bruce Henning
Keyword(s):  
Second Order ◽  
Short Stimulus

scholarly journals Spatial dependence of the nonlinear BOLD response at short stimulus duration

NeuroImage ◽  
2003 ◽  
Vol 18 (4) ◽  
pp. 990-1000 ◽  
Author(s):  
Josef Pfeuffer ◽  
Jeffrey C McCullough ◽  
Pierre-Francois Van de Moortele ◽  
Kamil Ugurbil ◽  
Xiaoping Hu
Keyword(s):  
Stimulus Duration ◽  
Spatial Dependence ◽  
Bold Response ◽  
Short Stimulus ◽  
Short Stimulus Duration

Dynamics and nonlinearities of the BOLD response at very short stimulus durations

2008 ◽  
Vol 26 (7) ◽  
pp. 853-862 ◽  
Author(s):  
Bariş Yeşilyurt ◽  
Kâmil Uğurbil ◽  
Kâmil Uludağ
Keyword(s):  
Bold Response ◽  
Short Stimulus

scholarly journals Mental Chronometry in the Pocket? Timing Accuracy of Web Applications on Touchscreen and Keyboard Devices

2019 ◽  
Author(s):  
Thomas Pronk ◽  
Reinout W. Wiers ◽  
Bert Molenkamp ◽  
Jaap Murre
Keyword(s):  
Web Applications ◽  
Response Times ◽  
Web Browsers ◽  
Validity And Reliability ◽  
Timing Accuracy ◽  
Mental Chronometry ◽  
Stimulus Timing ◽  
Short Stimulus ◽  
Technical Innovations ◽  
Software And Hardware

AbstractWeb applications can implement procedures for studying the speed of mental processes (mental chronometry). As web applications, these procedures can be administered via web-browsers on most commodity desktops, laptops, smartphones, and tablets. This approach to conducting mental chronometry offers various opportunities, such as increased scale, ease of data collection, and access to specific samples. However, validity and reliability may be threatened due to web applications on commodity devices having less accurate timing than specialized software and hardware. We have examined how accurately web applications time stimuli and register response times on commodity touchscreen and keyboard devices running a range of popular web-browsers. Additionally, we have explored the accuracy of a range of technical innovations for timing stimuli, presenting stimuli, and estimating stimulus duration. Results offer some guidelines as to what kind of methods may be most accurate, and what kind of mental chronometry paradigms may suitably be administered via web applications. In controlled circumstances, as can be realized in a lab setting, very accurate stimulus timing and moderately accurate Reaction Time (RT) measurements could be achieved on both touchscreen and keyboard devices. In uncontrolled circumstances, as may be encountered online, short stimulus durations (of up to 100 ms) may be inaccurate, and RT measurement may be affected by the occurrence of bi-modally distributed RT overestimations.

scholarly journals Case Report: Women, Be Aware that Your Vocal Charisma can Dwindle in Remote Meetings

2021 ◽  
Vol 5 ◽  
Author(s):  
Ingo Siegert ◽  
Oliver Niebuhr
Keyword(s):  
Case Report ◽  
Nonverbal Communication ◽  
Audio Signal ◽  
Signal Compression ◽  
Audio Compression ◽  
Transmission Bandwidth ◽  
Communication Signals ◽  
Signal Degradation ◽  
Female Speech ◽  
Short Stimulus

Remote meetings via Zoom, Skype, or Teams limit the range and richness of nonverbal communication signals. Not just because of the typically sub-optimal light, posture, and gaze conditions, but also because of the reduced speaker visibility. Consequently, the speaker’s voice becomes immensely important, especially when it comes to being persuasive and conveying charismatic attributes. However, to offer a reliable service and limit the transmission bandwidth, remote meeting tools heavily rely on signal compression. It has never been analyzed how this compression affects a speaker’s persuasive and overall charismatic impact. Our study addresses this gap for the audio signal. A perception experiment was carried out in which listeners rated short stimulus utterances with systematically varied compression rates and techniques. The scalar ratings concerned a set of charismatic speaker attributes. Results show that the applied audio compression significantly influences the assessment of a speaker’s charismatic impact and that, particularly female speakers seem to be systematically disadvantaged by audio compression rates and techniques. Their charismatic impact decreases over a larger range of different codecs; and this decrease is additionally also more strongly pronounced than for male speakers. We discuss these findings with respect to two possible explanations. The first explanation is signal-based: audio compression codecs could be generally optimized for male speech and, thus, degrade female speech more (particularly in terms of charisma-associated features). Alternatively, the explanation is in the ears of the listeners who are less forgiving of signal degradation when rating female speakers’ charisma.

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