Broad domains of histone marks in the highly compact Paramecium macronuclear genome

The unicellular ciliate Paramecium contains a large vegetative macronucleus with several unusual characteristics including an extremely high coding density and high polyploidy. As macronculear chromatin is believed to be devoid of heterochromatin our study characterizes the functional epigenomic organisation necessary for gene regulation and proper PolII activity. Histone marks (H3K4me3, H3K9ac, H3K27me3) revealed no narrow peaks but broad domains along gene bodies, whereas intergenic regions were devoid of nucleosomes. Our data implicates H3K4me3 levels inside ORFs to be the main factor to associate with gene expression and H3K27me3 appears to occur as a bistable domain with H3K4me3in plastic genes. Surprisingly, silent and lowly expressed genes show low nucleosome occupancy suggesting that gene inactivation does not involve increased nucleosome occupancy and chromatin condensation. Due to a high occupancy of Pol II along highly expressed ORFs, transcriptional elongation appears to be quite different to other species. This is supported by missing heptameric repeats in the C-terminal domain of Pol II and a divergent elongation system. Our data implies that unoccupied DNA is the default state, whereas gene activation requires nucleosome recruitment together with broad domains of H3K4me3. This could represent a buffer for paused Pol II along ORFs in absence of elongation factors of higher eukaryotes

Polycomb-group recruitment to a Drosophila target gene is the default state that is inhibited by a transcriptional activator

Polycomb-group (PcG) proteins are epigenetic regulators that maintain the transcriptional repression of target genes following their initial repression by transcription factors. PcG target genes are repressed in some cells, but active in others. Therefore, a mechanism must exist by which PcG proteins distinguish between the repressed and active states and only assemble repressive chromatin environments at target genes that are repressed. Here, we present experimental evidence that the repressed state of a Drosophila PcG target gene, giant (gt), is not identified by the presence of a repressor. Rather, de novo establishment of PcG-mediated silencing at gt is the default state that is prevented by the presence of an activator or coactivator, which may inhibit the catalytic activity of Polycomb-repressive complex 2 (PRC2).

How Perceptions of Caller Honesty Vary During Vishing Attacks That Include Highly Sensitive or Seemingly Innocuous Requests

Objective To understand how aspects of vishing calls (phishing phone calls) influence perceived visher honesty. Background Little is understood about how targeted individuals behave during vishing attacks. According to truth-default theory, people assume others are being honest until something triggers their suspicion. We investigated whether that was true during vishing attacks. Methods Twenty-four participants read written descriptions of eight real-world vishing calls. Half included highly sensitive requests; the remainder included seemingly innocuous requests. Participants rated visher honesty at multiple points during conversations. Results Participants initially perceived vishers to be honest. Honesty ratings decreased before requests occurred. Honesty ratings decreased further in response to highly sensitive requests, but not seemingly innocuous requests. Honesty ratings recovered somewhat, but only after highly sensitive requests. Conclusions The present results revealed five important insights: (1) people begin vishing conversations in the truth-default state, (2) certain aspects of vishing conversations serve as triggers, (3) other aspects of vishing conversations do not serve as triggers, (4) in certain situations, people’s perceptions of visher honesty improve, and, more generally, (5) truth-default theory may be a useful tool for understanding how targeted individuals behave during vishing attacks. Application Those developing systems that help users deal with suspected vishing attacks or penetration testing plans should consider (1) targeted individuals’ truth-bias, (2) the influence of visher demeanor on the likelihood of deception detection, (3) the influence of fabricated situations surrounding vishing requests on the likelihood of deception detection, and (4) targeted individuals’ lack of concern about seemingly innocuous requests.

Assessing criticality in pre-seizure single-neuron activity of human epileptic cortex

Epileptic seizures are characterized by abnormal and excessive neural activity, where cortical network dynamics seem to become unstable. However, most of the time, during seizure-free periods, cortex of epilepsy patients shows perfectly stable dynamics. This raises the question of how recurring instability can arise in the light of this stable default state. In this work, we examine two potential scenarios of seizure generation: (i) epileptic cortical areas might generally operate closer to instability, which would make epilepsy patients generally more susceptible to seizures, or (ii) epileptic cortical areas might drift systematically towards instability before seizure onset. We analyzed single-unit spike recordings from both the epileptogenic (focal) and the nonfocal cortical hemispheres of 20 epilepsy patients. We quantified the distance to instability in the framework of criticality, using a novel estimator, which enables an unbiased inference from a small set of recorded neurons. Surprisingly, we found no evidence for either scenario: Neither did focal areas generally operate closer to instability, nor were seizures preceded by a drift towards instability. In fact, our results from both pre-seizure and seizure-free intervals suggest that despite epilepsy, human cortex operates in the stable, slightly subcritical regime, just like cortex of other healthy mammalians.

How Neuronal Noises Influence the Spiking Neural Networks’s Cognitive Learning Process: A Preliminary Study

In neuroscience, the Default Mode Network (DMN), also known as the default network or the default-state network, is a large-scale brain network known to have highly correlated activities that are distinct from other networks in the brain. Many studies have revealed that DMNs can influence other cognitive functions to some extent. This paper is motivated by this idea and intends to further explore on how DMNs could help Spiking Neural Networks (SNNs) on image classification problems through an experimental study. The approach emphasizes the bionic meaning on model selection and parameters settings. For modeling, we select Leaky Integrate-and-Fire (LIF) as the neuron model, Additive White Gaussian Noise (AWGN) as the input DMN, and design the learning algorithm based on Spike-Timing-Dependent Plasticity (STDP). Then, we experiment on a two-layer SNN to evaluate the influence of DMN on classification accuracy, and on a three-layer SNN to examine the influence of DMN on structure evolution, where the results both appear positive. Finally, we discuss possible directions for future works.

Stage 1 Registered Report: Metacognitive asymmetries in visual perception

People have better metacognitive sensitivity for decisions about the presence compared to the absence of objects. However, it is not only objects themselves that can be present or absent, but also parts of objects and other visual features. Asymmetries in visual search indicate that a disadvantage for representing absence may operate at these levels as well. Furthermore, a processing advantage for surprising signals suggests that a presence/absence asymmetry may be explained by absence being passively represented as a default state, and presence as a default-violating surprise. It is unknown whether metacognitive asymmetry for judgements about presence and absence extend to these different levels of representation (object, feature, and default-violation). To address this question and test for a link between the representation of absence and default reasoning more generally, here we measure metacognitive sensitivity for discrimination judgments between stimuli that are identical except for the presence or absence of a distinguishing feature, and for stimuli that differ in their compliance with an expected default state.

Metacognitive asymmetries in visual perception

People have better metacognitive sensitivity for decisions about the presence compared to the absence of objects. However, it is not only objects themselves that can be present or absent, but also parts of objects and other visual features. Asymmetries in visual search indicate that a disadvantage for representing absence may operate at these levels as well. Furthermore, a processing advantage for surprising signals suggests that a presence/absence asymmetry may be explained by absence being passively represented as a default state, and presence as a default-violating surprise. It is unknown whether the metacognitive asymmetry for judgments about presence and absence extends to these different levels of representation (object, feature, and default violation). To address this question and test for a link between the representation of absence and default reasoning more generally, here we measure metacognitive sensitivity for discrimination judgments between stimuli that are identical except for the presence or absence of a distinguishing feature, and for stimuli that differ in their compliance with an expected default state.

A double negative post-transcriptional regulatory circuit underlies the virgin behavioral state

The survival and reproductive success of animals depends on the ability to harmonize their external behaviors with their internal states. For example, females conduct numerous social programs that are distinctive to virgins, compared to post-mated and/or pregnant individuals. In Drosophila, the fact that this post-mating switch is initiated by seminal factors implies that the default state is virgin. However, we recently showed that loss of miR-iab-4/8-mediated repression of the transcription factor Homothorax (Hth) within the abdominal ventral nerve cord (VNC) causes virgin females to execute mated behaviors. To elucidate new components of this post-transcriptional regulatory circuit, we used genomic analysis of mir-iab-4/8 deletion and hth-miRNA binding site mutants (hth[BSmut]) to elucidate doublesex (dsx) as a critical downstream factor. While Dsx has mostly been studied during sex-specific differentiation, its activities in neurons are little known. We find that accumulation of Dsx in the CNS is highly complementary to Hth, and downregulated in miRNA/hth[BSmut] mutants. Moreover, virgin behavior is highly dose-sensitive to developmental dsx function. Strikingly, depletion of Dsx in SAG-1 cells, a highly restricted set of abdominal neurons, abrogates female virgin conducts in favor of mated behavioral programs. Thus, a double negative post-transcriptional pathway in the VNC (miR-iab-4/8 -| Hth -| Dsx) specifies the virgin behavioral state.

Research on Starting Control Method of New-Energy Vehicle Based on State Machine

In order to improve the starting smoothness of new-energy vehicles under multiple working conditions and meet the driving intention better, and to make the control strategy have high portability and integration, a starting control method for vehicle based on state machine is designed. Based on inclination, starting of vehicle is divided into three working conditions: flat road, slight slope and steep slope. The method of vehicle starting control is designed, which includes five control states: default state control, torque pre-loading control, anti-rollback control, pedal control and PI (Proportion-Intergral) creep control. The simulation is carried out under the conditions of flat road, slight slope and steep slope. In terms of flat road and light slope, the vehicle travels below 3 km/h according to the driver’s intention, the speed is stable at 8 km/h during the creeping control phase and the jerk is lower than 5 m/s3. In terms of steep slope, the speed is controlled at 0 km/h basically and the 10 s-rollback distance is less than 0.04 m. The results show that the strategy can fully meet the driver’s intention with lower jerk, better dynamic and stability, and the method can achieve the demand of new-energy vehicle starting control.

Dual n-back training improves functional connectivity of the right inferior frontal gyrus at rest

Several studies have shown that the benefits of working memory (WM) training can be attributed to functional and structural neural changes in the underlying neural substrate. In the current study, we investigated whether the functional connectivity of the brain at rest in the default mode network (DMN) changes with WM training. We varied the complexity of the training intervention so, that half of the participants attended dual n-back training whereas the other half attended single n-back training. This way we could assess the effects of different training task parameters on possible connectivity changes. After 16 training sessions, the dual n-back training group showed improved performance accompanied by increased functional connectivity of the ventral DMN in the right inferior frontal gyrus, which correlated with improvements in WM. We also observed decreased functional connectivity in the left superior parietal cortex in this group. The single n-back training group did not show significant training-related changes. These results show that a demanding short-term WM training intervention can alter the default state of the brain.