The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform
Tobias U Hauser - One of the best experts on this subject based on the ideXlab platform.
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reliability of web based affective auditory Stimulus Presentation
Behavior Research Methods, 2021Co-Authors: Tricia X F Seow, Tobias U HauserAbstract:Web-based experimental testing has seen exponential growth in psychology and cognitive neuroscience. However, paradigms involving affective auditory stimuli have yet to adapt to the online approach due to concerns about the lack of experimental control and other technical challenges. In this study, we assessed whether sounds commonly used to evoke affective responses in-lab can be used online. Using recent developments to increase sound Presentation quality, we selected 15 commonly used sound stimuli and assessed their impact on valence and arousal states in a web-based experiment. Our results reveal good inter-rater and test-retest reliabilities, with results comparable to in-lab studies. Additionally, we compared a variety of previously used unpleasant stimuli, allowing us to identify the most aversive among these sounds. Our findings demonstrate that affective sounds can be reliably delivered through web-based platforms, which help facilitate the development of new auditory paradigms for affective online experiments.
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reliability of web based affective auditory Stimulus Presentation
bioRxiv, 2021Co-Authors: Tricia X F Seow, Tobias U HauserAbstract:Web-based experimental testing has seen an exponential growth in psychology and cognitive neuroscience. However, paradigms involving affective auditory stimuli have yet to adapt to the online approach due to concerns about the lack of experimental control and other technical challenges. In this study, we assessed if sounds commonly used to evoke affective responses in-lab can be used online. Using recent developments to increase sound Presentation quality, we selected 15 commonly used sound stimuli and assessed their impact on valence and arousal states in a web-based experiment. Our results reveal good test-retest reliability and good internal consistency, with results comparable to in-lab studies. Additionally, we compared a variety of previously used unpleasant stimuli, allowing us to identify the most aversive of these sounds. Our findings demonstrate that affective sounds can be reliably delivered through web-based platforms, which helps facilitate the development of new auditory paradigms for affective online experiments.
Rolf Kotter - One of the best experts on this subject based on the ideXlab platform.
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a primer of visual Stimulus Presentation software
Frontiers in Neuroinformatics, 2009Co-Authors: Rolf KotterAbstract:The visual system has been the most widely studied sensory system in neuroscience during the last decades. A reliable and flexible visual Stimulus Presentation tool is one of the most important prerequisites for a thorough analysis of its sensory processing characteristics. While almost all sensory systems labs have created some home-grown solutions, these are not easily transferable from one lab to another or from one Presentation platform to another. In addition, several stimuli are hard to generate with the desired accuracy in timing, color and luminance, 3D rendering or stereopsis. Vision Egg (Straw, 2008) is a more widely used software library, designed originally to probe the visual system of the fly. It is an open source and platform-independent software package built on top of Python (as the programming language) and OpenGL (for graphics instructions). For a well versed programmer, Vision Egg achieves its goals very well, providing a powerful and highly optimized system for visual Stimulus Presentation and interactions with hardware – including the ability to run experiments remotely across a network (via TCP/IP). While historically the Vision Egg software strongly adheres to an object-oriented model of programming this can be hard to understand for relatively inexperienced programmers. For instance, the temporal control of experiments in Vision Egg is predominantly through the use of Presentation loops, whereby the user sets an object to run for a given length of time, attaches stimuli to it, assigns it to a screen, and then tells the object to “go”. This “mainloop-and-callback” mechanism of flow control has advantages where stimuli continue to run between trials. The alternative, however, of an explicit sequence of control statements can also be implemented (see Figure 2 of Straw, 2008). Table Table11 (adapted from Peirce, 2007) gives a comparison of various features of four well known Stimulus Presentation programs. Two of these (Vision Egg and PsychoPy) have very similar philosophies, are both implemented in Python, and differed originally in their low-latency real-time capabilities. The most substantive differences between them today are that Vision Egg offers relatively simple perspective corrected stimuli utilizing the 3D nature of OpenGL, while PsychoPy has an automated luminance calibration utility and interfaces more easily with certain types of hardware. Furthermore, the primary development platform of the Vision Egg is GNU/Linux, while it appears to be Windows for PsychoPy. Table 1 Comparison of several frequently used software packages for visual Stimulus Presentation. Another interesting issue discussed shortly in Straw's paper is the feasibility of setting up a Stimulus library in form of a database that could be downloaded and used with different Presentation environments. As everyone who has developed databases knows, there is more involved in such a project than just storing bitmaps (or sequences thereof) of a standard number of pixels. For example, the issues of frame rate, display luminance and position calibration, and synchronization with data acquisition and other hardware would all need to be addressed. Even further, the creation of a universal language for specifying sensory stimuli would be of great interest. Altogether this paper by Straw on the Vision Egg gives a fairly technical account of many relevant hardware and software considerations, but is nevertheless a well readable primer of considerations when deciding on what visual Stimulus software to choose or extend.
Tricia X F Seow - One of the best experts on this subject based on the ideXlab platform.
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reliability of web based affective auditory Stimulus Presentation
Behavior Research Methods, 2021Co-Authors: Tricia X F Seow, Tobias U HauserAbstract:Web-based experimental testing has seen exponential growth in psychology and cognitive neuroscience. However, paradigms involving affective auditory stimuli have yet to adapt to the online approach due to concerns about the lack of experimental control and other technical challenges. In this study, we assessed whether sounds commonly used to evoke affective responses in-lab can be used online. Using recent developments to increase sound Presentation quality, we selected 15 commonly used sound stimuli and assessed their impact on valence and arousal states in a web-based experiment. Our results reveal good inter-rater and test-retest reliabilities, with results comparable to in-lab studies. Additionally, we compared a variety of previously used unpleasant stimuli, allowing us to identify the most aversive among these sounds. Our findings demonstrate that affective sounds can be reliably delivered through web-based platforms, which help facilitate the development of new auditory paradigms for affective online experiments.
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reliability of web based affective auditory Stimulus Presentation
bioRxiv, 2021Co-Authors: Tricia X F Seow, Tobias U HauserAbstract:Web-based experimental testing has seen an exponential growth in psychology and cognitive neuroscience. However, paradigms involving affective auditory stimuli have yet to adapt to the online approach due to concerns about the lack of experimental control and other technical challenges. In this study, we assessed if sounds commonly used to evoke affective responses in-lab can be used online. Using recent developments to increase sound Presentation quality, we selected 15 commonly used sound stimuli and assessed their impact on valence and arousal states in a web-based experiment. Our results reveal good test-retest reliability and good internal consistency, with results comparable to in-lab studies. Additionally, we compared a variety of previously used unpleasant stimuli, allowing us to identify the most aversive of these sounds. Our findings demonstrate that affective sounds can be reliably delivered through web-based platforms, which helps facilitate the development of new auditory paradigms for affective online experiments.
Sanne Ten Oever - One of the best experts on this subject based on the ideXlab platform.
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Does alpha phase modulate visual target detection? Three experiments with tACS phase-based Stimulus Presentation
bioRxiv, 2019Co-Authors: Tom A. De Graaf, Alix Thomson, Shanice E.w. Janssens, Sander Van Bree, Sanne Ten Oever, Alexander T. SackAbstract:In recent years the influence of alpha (7-13 Hz) phase on visual processing has received a lot of attention. Magneto-/encephalography (M/EEG) studies showed that alpha phase indexes visual excitability and task performance. If occipital alpha phase is functionally relevant, the phase of occipital alpha-frequency transcranial alternating current stimulation (tACS) could modulate visual processing. Visual stimuli presented at different pre-determined, experimentally controlled, phases of the entraining tACS signal should then result in an oscillatory pattern of visual performance. We studied this in a series of experiments. In experiment one, we applied 10 Hz tACS to right occipital cortex (O2) and used independent psychophysical staircases to obtain contrast thresholds for detection of visual gratings in left or right hemifield, in six equidistant tACS phase conditions. In experiments two and three, tACS was at EEG-based individual peak alpha frequency. In experiment two, we measured detection rates for gratings with (pseudo-)fixed contrast levels. In experiment three, participants detected brief luminance changes in a custom-built LED device, at eight equidistant alpha phases. In none of the experiments did the primary outcome measure over phase conditions consistently reflect a one-cycle sinusoid as predicted. However, post-hoc analyses of reaction times (RT) suggested that tACS alpha phase did modulate RT in both experiments 1 and 2 (not measured in experiment 3). This observation is in line with the idea that alpha phase causally gates visual inputs through cortical excitability modulation.
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Stimulus Presentation at specific neuronal oscillatory phases experimentally controlled with tacs implementation and applications
Frontiers in Cellular Neuroscience, 2016Co-Authors: Sanne Ten Oever, Tom A. De Graaf, Alexander T. Sack, Charlie Bonnemayer, Jacco Ronner, Lars RieckeAbstract:In recent years it has become increasingly clear that both the power and phase of oscillatory brain activity can influence the processing and perception of sensory stimuli. Transcranial alternating current stimulation (tACS) can phase-align and amplify endogenous brain oscillations and has often been used to control and thereby study oscillatory power. Causal investigation of oscillatory phase is more difficult, as it requires precise real-time temporal control over both oscillatory phase and sensory stimulation. Here, we present hardware and software solutions allowing temporally precise Presentation of sensory stimuli during tACS at desired tACS phases, enabling causal investigations of oscillatory phase. We developed freely available and easy to use software, which can be coupled with standard commercially available hardware to allow flexible and multi-modal Stimulus Presentation (visual, auditory, magnetic stimuli, etc.) at pre-determined tACS-phases, opening up a range of new research opportunities. We validate that Stimulus Presentation at tACS phase in our setup is accurate to the sub-millisecond level with high inter-trial consistency. Conventional methods investigating the role of oscillatory phase such as magneto-/electroencephalography can only provide correlational evidence. Using brain stimulation with the described methodology enables investigations of the causal role of oscillatory phase. This setup turns oscillatory phase into an independent variable, allowing innovative and systematic studies of its functional impact on perception and cognition.
Michael Hutchinson - One of the best experts on this subject based on the ideXlab platform.
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a comparison of Stimulus Presentation methods in temporal discrimination testing
Physiological Measurement, 2017Co-Authors: Eavan Mc Govern, John S Butler, Ines Beiser, Laura Williams, Brendan Quinlivan, Richard B Reilly, Shruti Narasiham, Rebecca Beck, Sean Oriordan, Michael HutchinsonAbstract:The temporal discrimination threshold (TDT) is the shortest time interval at which an individual detects two stimuli to be asynchronous (normal = 30-50 ms). It has been shown to be abnormal in patients with disorders affecting the basal ganglia including adult onset idiopathic focal dystonia (AOIFD). Up to 97% of patients have an abnormal TDT with age- and sex-related penetrance in unaffected relatives, demonstrating an autosomal dominant inheritance pattern. These findings support the use of the TDT as a pre-clinical biomarker for AOIFD. The usual Stimulus Presentation method involves the Presentation of progressively asynchronous stimuli; when three sequential stimuli are reported asynchronous is taken as a participant's TDT. To investigate the robustness of the 'staircase' method of Presentation, we introduced a method of randomised Presentation order to explore any potential 'learning effect' that may be associated with this existing method. The aim of this study was to investigate differences in temporal discrimination using two methods of Stimulus Presentation. Thirty healthy volunteers were recruited to the study (mean age 33.73 ± 3.4 years). Visual and tactile TDT testing using a staircase and randomised method of Presentation order was carried out in a single session. There was a strong relationship between the staircase and random method for TDT values. This observed consistency between testing methods suggests that the existing experimental approach is a robust method of recording an individual's TDT. In addition, our newly devised randomised paradigm is a reproducible and more efficient method for data acquisition in the clinic setting. However, the two Presentation methods yield different absolute TDT results and either of the two methods should be used uniformly in all participants in any one particular study.
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comparing Stimulus Presentation methods in temporal discrimintation testing
Journal of Neurology Neurosurgery and Psychiatry, 2016Co-Authors: Eavan Mcgovern, John S Butler, Ines Beiser, Laura Williams, Brendan Quinlivan, Sean O Riordan, Richard B Reilly, Michael HutchinsonAbstract:Objective To investigate any differences in temporal discrimination using two methods of Stimulus Presentation. Background Temporal discrimination threshold (TDT) is a measure of the point at which an individual determines two sensory stimuli to be asynchronous (normal=30–50 ms). The classic approach involves Presentation of progressively-asynchronous stimuli to an individual. The TDT is taken as the first of three consecutively-reported asynchronous stimuli. Due to the potential for a learned effect from this method of Presentation, a method of constant stimuli with randomised Presentation order was also employed. Methods Ten healthy volunteers were recruited to the study. Visual and tactile TDT testing using the classic and random method of Presentation was carried out in a single session. The mean TDT score was calculated for each participant. The data was fitted to a cumulative Gaussian function from which the point of subjective equality (PSE) and the just noticeable difference (JND) was calculated. Results The mean values for the sequential method are as follows; TDT=32.03 ms, PSE=23.11 ms, JND=13.71 ms. The mean values for the random method are as follows; TDT 52.26 ms, PSE 33.35 ms, JND 28.58 ms. Conclusion Although a difference was observed in the results between Stimulus Presentation, there was a trending correlation between the PSE values for the two Stimulus Presentation types. This suggests that while the absolute values were different, the relative values were consistent. While our study is limited by number size and future research is required, preliminary results suggest the TDT is a robust measure.
