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Comparison of Different Spike Train Synchrony Measures Regarding Their Robustness to Erroneous Data from Bicuculline-Induced Epileptiform Activity
No full textAs synchronized activity is associated with basic brain functions and pathological states, spike train synchrony has become an important measure to analyze experimental neuronal data. Many measures of spike train synchrony have been proposed, but there is no gold standard allowing for comparison of results from different experiments. This work aims to provide guidance on which synchrony measure is best suited to quantify the effect of epileptiform-inducing substances (e.g., bicuculline, BIC) in in vitro neuronal spike train data. Spike train data from recordings are likely to suffer from erroneous spike detection, such as missed spikes (false negative) or noise (false positive). Therefore, different timescale-dependent (cross-correlation, mutual information, spike time tiling coefficient) and timescale-independent (Spike-contrast, phase synchronization (PS), A-SPIKE-synchronization, A-ISI-distance, ARI-SPIKE-distance) synchrony measures were compared in terms of their robustness to erroneous spike trains. For this purpose, erroneous spike trains were generated by randomly adding (false positive) or deleting (false negative) spikes (in silico manipulated data) from experimental data. In addition, experimental data were analyzed using different spike detection threshold factors in order to confirm the robustness of the synchrony measures. All experimental data were recorded from cortical neuronal networks on microelectrode array chips, which show epileptiform activity induced by the substance BIC. As a result of the in silico manipulated data, Spike-contrast was the only measure that was robust to false-negative as well as false-positive spikes. Analyzing the experimental data set revealed that all measures were able to capture the effect of BIC in a statistically significant way, with Spike-contrast showing the highest statistical significance even at low spike detection thresholds. In summary, we suggest using Spike contrast to complement established synchrony measures because it is timescale independent and robust to erroneous spike trains
Microchannels inside bulk PMMA generated by femtosecond laser using adaptive beam shaping
No full textIn this contribution, we report on the generation of internal microchannels with basically unlimited channel length inside of PMMA bulk material by femtosecond laser. A precisely controllable and stable circular channel cross section is obtained by using a spatial light modulator to compensate the writing depth depending spherical aberration. Furthermore, the generation of a rotatable elliptical input beam by adaptive optics ensures a fitting of the beam shaping to the writing direction. In this study, we report on both, the effect of the ellipticity of the input beam and the effect of a correction of the spherical aberration on the circularity of the resulting internal microchannels. Moreover, we demonstrate the application of this writing technique by creating microfluidic testing structures inside of a transparent standard polymer
Rapid fabrication of precise glass axicon arrays by an all laser-based manufacturing technology
No full textSafe Development Environments for Radiation Tracing Robots
No full textRobots can substitute for men in radioactively-contaminated areas. This is a suitable field to deploy robots for measurements, repair, or clearance, but development and test of such robots could be dangerous, because radiation sources need to be handled. To avoid these hazards in development or public demonstrations, safe alternatives to radiation samples have been sought using an already existing robot
(EtaBot). One proposed solution is an optical substitution (“light follower”), the other one a fully-digital simulation of the contaminated area and the robot movement inside it using a hardware-in-the-loop simulator (HiL)
Information load in escalation situations: combustive agent or counteractive measure?
No full textThis experimental study analyzes how a key factor, information load, influences decision making in escalation situations, i.e., in situations in which decision mak- ers reinvest further resources in a losing course of action, even when accounting information indicates that the project is performing poorly and should be discontin- ued. This study synthesizes prior escalation research with information overload and investigates how different levels of information load influence the escalation of com- mitment. Our findings reveal a U-shaped effect of information load: When decision makers face negative feedback, a higher information load mitigates the escalation tendency up to a certain point. However, beyond this point, more information rein- forces the escalation tendency. Moreover, we find that the type of feedback affects self-justification, and we find a negative and significant interaction between informa- tion load and self-justification in negative-feedback cases. Thus, studies investigat- ing escalation of commitment should control for self-justification and information load when utilizing high levels of information load. Finally, in the positive-feedback condition, higher information load encourages decision makers to continue promis- ing courses of action, i.e., increases decision-making performance
