Errorless and errorful learning modulated by transcranial direct current stimulation

Background

Caspase-3 is one of the most downstream enzymes activated in the apoptotic pathway. In caspase-3 deficient mice, loss of cochlear hair cells and spiral ganglion cells coincide closely with hearing loss. In contrast with the auditory system, details of the vestibular phenotype have not been characterized. Here we report the vestibular phenotype and inner ear anatomy in the caspase-3 deficient (Casp3 ^-/- ) mouse strain.

Results

Average ABR thresholds of Casp3 ^-/- mice were significantly elevated (P < 0.05) compared to Casp3 ^+/- mice and Casp3 ^+/+ mice at 3 months of age. In DPOAE testing, distortion product 2F1-F2 was significantly decreased (P < 0.05) in Casp3 ^-/- mice, whereas Casp3 ^+/- and Casp3 ^+/+ mice showed normal and comparable values to each other. Casp3 ^-/- mice were hyperactive and exhibited circling behavior when excited. In lateral canal VOR testing, Casp3 ^-/- mice had minimal response to any of the stimuli tested, whereas Casp3 ^+/- mice had an intermediate response compared to Casp3 ^+/+ mice. Inner ear anatomical and histological analysis revealed gross hypomorphism of the vestibular organs, in which the main site was the anterior semicircular canal. Hair cell numbers in the anterior- and lateral crista, and utricle were significantly smaller in Casp3 ^-/- mice whereas the Casp3 ^+/- and Casp3 ^+/+ mice had normal hair cell numbers.

Conclusions

These results indicate that caspase-3 is essential for correct functioning of the cochlea as well as normal development and function of the vestibule.     

Bifrontal transcranial direct current stimulation slows reaction time in a working memory task

Background  

Weak transcortical direct current stimulation (tDCS) applied to the cortex can shift the membrane potential of superficial neurons thereby modulating cortical excitability and activity. Here we test the possibility of modifying ongoing activity associated with working memory by tDCS. The concept of working memory applies to a system that is capable of transiently storing and manipulating information, as an integral part of the human memory system. We applied anodal and cathodal transcranial direct current (tDCS) stimulation (260 μA) bilaterally at fronto-cortical electrode sites on the scalp over 15 min repeatedly (15 sec-on/15 sec-off) as well as sham-tDCS while subjects performed a modified Sternberg task.     

自制微弱直流电流检测装置

介绍了用音乐架卡和压电陶瓷片制作的检测微弱直流电流的实验装置。     

Contour level object detection with top-down information

This paper presents a contour level object detection approach. In contrast to conventional bounding box results, we give out the salient closed contour of the object, which provides a possibility of semantic analysis for the object. We get the salient closed contour with Ratio Contour algorithm. The top-down information needed by salient closed contour extraction is based on the well-known Bag-of-Features methodology. Our top-down information based contour extraction and completion is much more efficient and robust than many related approaches lack of the top-down information. We also propose a novel post-processing framework for object detection. With low threshold and a refined binary classifier, we can get stable high performance. We evaluate our approaches on UIUC cars dataset. We show that our approaches apparently improve the performance of object detections under clutter.     

Accurate object detection with a discriminative shape model

Discriminative model over bag-of-visual-words representation significantly improves the accuracy of object detection under clutter. However, it encounters bottleneck because of completely ignoring geometric constraint between features. On the contrary, to detect object accurately explicit shape model heavily relies on geometric information of the object, which as a result lacks of discriminative power. In this paper, we present a discriminative shape model to make use of the advantages of the two models based on the insight that the two models are essentially complementary. Discriminative model provides discriminative power, while shape model encodes geometry. The cost function that we used to distinguish objects considers both the detection maps of the discriminative model and the result of shape matching. In this cost function, we adopt a novel way to deal with multi-scale detection maps. We show that this cost function has very strong discriminative power, which makes learning a discriminative threshold for full object detection possible. For shape model, we also present a scheme for learning a good shape model from noisy images. Experiments on UIUC Car and Weizmann–Shotton horses show state-of-the-art performance of our model.     

Aging is associated with increased collagen type IV accumulation in the basal lamina of human cerebral microvessels

Background  

Microvascular alterations contribute to the development of stroke and vascular dementia. The goal of this study was to evaluate age and hypertension related changes of the basal lamina in cerebral microvessels of individuals, who died from non-cerebral causes.     

Transcranial direct current stimulation of the prefrontal cortex modulates working memory performance: combined behavioural and electrophysiological evidence

Background  

Transcranial direct current stimulation (tDCS) is a technique that can systematically modify behaviour by inducing changes in the underlying brain function. In order to better understand the neuromodulatory effect of tDCS, the present study examined the impact of tDCS on performance in a working memory (WM) task and its underlying neural activity. In two experimental sessions, participants performed a letter two-back WM task after sham and either anodal or cathodal tDCS over the left dorsolateral prefrontal cortex (DLPFC).     

Transcranial direct current stimulation for the treatment of tinnitus: a review of clinical trials and mechanisms of action

Background

Tinnitus is the perception of sound in the absence of any external acoustic stimulation. Transcranial direct current stimulation (tDCS) has shown promising though heterogeneous therapeutic outcomes for tinnitus. The present study aims to review the recent advances in applications of tDCS for tinnitus treatment. In addition, the clinical efficacy and main mechanisms of action of tDCS on suppressing tinnitus are discussed.

Methods

The study was performed in accordance with the PRISMA guidelines. The databases of the PubMed (1980–2018), Embase (1980–2018), PsycINFO (1850–2018), CINAHL, Web of Science, BIOSIS Previews (1990–2018), Cambridge Scientific Abstracts (1990–2018), and google scholar (1980–2018) using the set search terms. The date of the most recent search was 20 May, 2018. The randomized controlled trials that have assessed at least one therapeutic outcome measured before and after tDCS intervention were included in the final analysis.

Results

Different tDCS protocols were used for tinnitus ranging single to repeated sessions (up to 10) consisting of daily single session of 15 to 20-min and current intensities ranging 1–2 mA. Dorsolateral prefrontal cortex (DLPFC) and auditory cortex are the main targets of stimulation. Both single and repeated sessions showed moderate to significant treatment effects on tinnitus symptoms. In addition to improvements in tinnitus symptoms, the tDCS interventions particularly bifrontal DLPFC showed beneficial outcomes on depression and anxiety comorbid with tinnitus. Heterogeneities in the type of tinnitus, tDCS devices, protocols, and site of stimulation made the systematic reviews of the literature difficult. However, the current evidence shows that tDCS can be developed as an adjunct or complementary treatment for intractable tinnitus. TDCS may be a safe and cost-effective treatment for tinnitus in the short-term application.

Conclusions

The current literature shows moderate to significant therapeutic efficacy of tDCS on tinnitus symptoms. Further randomized placebo-controlled double-blind trials with large sample sizes are needed to reach a definitive conclusion on the efficacy of tDCS for tinnitus. Future studies should further focus on developing efficient disease- and patient-specific protocols.

     

直流和交流Josephson效应的研究

基于Feynman模型得到的Josephson方程,在求解过程中采取了ρ1=ρ2的假设,但这个假设在数学处理上并不严格。为了得到严格的结果,未进行上述假设,通过解微分方程得到了严格的Josephson方程,结果显示在一定条件下才能得到通常所说的Josephson方程。     

Theoretical analysis of transcranial Hall-effect stimulation based on passive cable model

Transcranial Hall-effect stimulation(THS) is a new stimulation method in which an ultrasonic wave in a static magnetic field generates an electric field in an area of interest such as in the brain to modulate neuronal activities. However, the biophysical basis of simulating the neurons remains unknown. To address this problem, we perform a theoretical analysis based on a passive cable model to investigate the THS mechanism of neurons. Nerve tissues are conductive; an ultrasonic wave can move ions embedded in the tissue in a static magnetic field to generate an electric field(due to Lorentz force).In this study, a simulation model for an ultrasonically induced electric field in a static magnetic field is derived. Then,based on the passive cable model, the analytical solution for the voltage distribution in a nerve tissue is determined. The simulation results showthat THS can generate a voltage to stimulate neurons. Because the THS method possesses a higher spatial resolution and a deeper penetration depth, it shows promise as a tool for treating or rehabilitating neuropsychiatric disorders.     

混沌激光实现异质物大小和位置的光学检测

利用混沌激光实现一定浓度脂肪乳液中异质物大小和位置的光学检测,实验采用混沌激光作为光源,并将光信号分为两路,一路信号用于探测脂肪乳液中的异质物信息,另外一路直接经过光电探测器作为参考信号,将两路光信号由光电探测器接收,通过信号处理系统进行互相关,分析混沌激光的互相关峰值信息,可得到异质物的大小和位置信息;通过混沌激光实现异质物信息分析的理论模型,建立混沌相关信号峰值信息与异质物大小和位置之间的关系,并且通过实验验证。结果表明:采用混沌互相关法可以对异质物大小和位置坐标进行探测。     

Positive current correlations associated with super-Poissonian shot noise

We report on shot noise cross spectrum measurements in a beam splitter configuration. Electrons tunneling through potential barriers are incident on a beam splitter and scattered into two separate channels. Such a partition process introduces correlations between the fluctuations of the two currents. Our work has confirmed that the generally expected negative correlations resulted from sub-Poissonian electron sources. More interestingly, positive cross correlations associated with barriers exhibiting super-Poissonian shot noise have also been observed. We have found that both positive and negative correlations can be related to the noise properties of the electron source.     

Two-temperature channel model of a direct current arc

A relatively simple method is proposed for computing the gas and electron temperatures in an arc plasmotron channel within the framework of the self-consistent two-temperature channel model of an arc discharge. This method affords the possibility of obtaining the gas and electron temperature distribution with good enough accuracy for given discharge parameters (current intensity in the discharge, power inserted in the discharge, etc.) as a function of the radial coordinate in both nonequilibrium (T_e T_ai) and quasi-equilibrium (T_e = T_ai within the current conducting channel) cases. The results obtained can be utilized in model computations to estimate the gas and electron temperatures as well, possibly, as in a number of engineering computations.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 7, pp. 80–86, July, 1990.The author is grateful to L. A. Rachevskii for useful discussion of results of the research.     

高温超导线圈交流通流失超检测方法的实验研究

目前的失超检测的方法多针对超导线圈的直流工作状态。在交流损耗等实验研究及部分电力应用中,超导线圈将工作在交流通流状态。为了保障这种情况下超导线圈的安全,需要进行交流失超检测方法的研究。设计了用于高温超导线圈交流通流的失超检测方法,将桥路交流电压信号转换为直流信号后,对工作在交流通流情况下的超导线圈的失超状态进行判断。通过搭建实验平台进行了相关的实验。实验结果显示,采用这种方法能够有效地对工作在交流情况下的超导线圈进行失超检测。     

Enhancement effect of high-frequency noise of injection lasers with reflected waves due to direct modulation

It is found experimentally that the high-frequency noise of an injection laser associated with wave injection due to external reflection is significantly increased when the direct modulation is applied. It is clarified that the noise enhancement effect is caused by the increasing of the quantum shot noise of the injection laser due to the current modulation. The high- frequency noise of the narrow stripe laser is smaller than that of the wide stripe laser.     

Experimental observation of direct current voltage-induced phase synchronization

The dynamics of two uncoupled distinct Chua circuits driven by a common direct current voltage is explored experimentally. It was found that, with increasing current intensity, the dominant frequencies of these two Chua circuits will first vary at different speeds, approach an identical value for a certain current intensity and then separate. Techniques such as synchronization index and phase difference distribution were employed to analyze the phase coherence between these two Chua circuits.     

Automation of the direct current comparator resistance bridge

The direct current comparator resistance bridge, Model 9975, manufactured by Guildline Instruments, Inc., which permits electrical resistance measurements up to eight digits, has been fully automated. Details of this automation are described in this paper. The performance of the automated bridge is demonstrated with applications to electrical resistivity studies on some metallic alloys.     

Adaptive and optimal detection of elastic object scattering with single-channel monostatic iterative time reversal

In active sonar operation,the presence of background reverberation and the low signal-to-noise ratio hinder the detection of targets.This paper investigates the application of single-channel monostatic iterative time reversal to mitigate the difficulties by exploiting the resonances of the target.Theoretical analysis indicates that the iterative process will adaptively lead echoes to converge to a narrowband signal corresponding to a scattering object’s dominant resonance mode,thus optimising the return level.The experiments in detection of targets in free field and near a planar interface have been performed.The results illustrate the feasibility of the method.