Sustaining attention in visuomotor timing is associated with location-based binding.

Maintaining focus of attention over prolonged periods can be challenging, especially when the target stimulus is absent from the temporal sequence. Prior research has shown that a temporal attentional cue filling in the temporal blank can improve sustained attention: in a sustained visual attention task requiring synchronizing finger tapping with a temporally regular sequence composed of brief flash disks interleaved with blank periods, task performance was improved when a continuous fixation point that served as a temporal attentional cue was presented superimposed on the disk stimulus. To test the hypothesis that binding the temporal attentional cue with the target temporal sequence by spatial overlapping is crucial for enhancing sustained attention, the present study conducted a series of three experiments that deconstructed the bound connection between the cue and the sequence stimulus. In Experiment 1, the cue was placed above or below a flash disk. In Experiment 2, the cue was between two vertically arranged flash disks. In Experiment 3, the cue was in a flash ring. No significant effect of sustained attention improvement was found in any of the three experiments. Experiment 4 further replicated these null results and the previously observed effect of sustained attention improvement when the temporal cue was superimposed on the sequence stimulus. Our finding demonstrates that binding by spatial overlapping during the temporal blank when the sequence stimulus is absent is critical for enhancing sustained attention, which should be beneficial for improving performance across a broader range of tasks that require prolonged maintenance of attention.

Alpha peak activity in resting-state EEG is associated with depressive score.

Introduction: Depression is a serious psychiatric disorder characterized by prolonged sadness, loss of interest or pleasure. The dominant alpha peak activity in resting-state EEG is suggested to be an intrinsic neural marker for diagnosis of mental disorders. Methods: To investigate an association between alpha peak activity and depression severity, the present study recorded resting-state EEG (EGI 128 channels, off-line average reference, source reconstruction by a distributed inverse method with the sLORETA normalization, parcellation of 68 Desikan-Killiany regions) from 155 patients with depression (42 males, mean age 35 years) and acquired patients' scores of Self-Rating Depression Scales. We measured both the alpha peak amplitude that is more related to synchronous neural discharging and the alpha peak frequency that is more associated with brain metabolism. Results: The results showed that over widely distributed brain regions, individual patients' alpha peak amplitudes were negatively correlated with their depressive scores, and individual patients' alpha peak frequencies were positively correlated with their depressive scores. Discussion: These results reveal that alpha peak amplitude and frequency are associated with self-rating depressive score in different manners, and the finding suggests the potential of alpha peak activity in resting-state EEG acting as an important neural factor in evaluation of depression severity in supplement to diagnosis.

Emotional body expressions facilitate working memory: Evidence from the n-back task.

In daily life, individuals need to recognize and update emotional information from others' changing body expressions. However, whether emotional bodies can enhance working memory (WM) remains unknown. In the present study, participants completed a modified n-back task, in which they were required to indicate whether a presented image of an emotional body matched that of an item displayed before each block (0-back) or two positions previously (2-back). Each block comprised only fear, happiness, or neutral. We found that in the 0-back trials, when compared with neutral body expressions, the participants took less time and showed comparable ceiling effects for accuracy in happy bodies followed by fearful bodies. When WM load increased to 2-back, both fearful and happy bodies significantly facilitated WM performance (i.e., faster reaction time and higher accuracy) relative to neutral conditions. In summary, the current findings reveal the enhancement effect of emotional body expressions on WM and highlight the importance of emotional action information in WM.

Tailoring the phase transition of silver selenide at the atomistic scale.

Thermoelectric materials provide promising solutions for energy harvesting from the environment. Silver selenide (Ag2Se) material attracts much attention due to its excellent thermoelectric properties under superionic phase transition. However, the optimal thermoelectric figure of merit occurs during the phase transition at high temperatures, making low-temperature devices unable to benefit from their best thermoelectric performance. Here, we tailored the phase transition process of Ag2Se materials with various sizes, and probed the phase transition temperature by in situ transmission electron microscopy. By tuning the motion of the atoms near the surface using size-dependent surface energy, the phase transition-induced process is tailored towards low temperatures. This work paves the way for future phase transition engineering to enhance thermoelectric performance.

Review of electrical stimulus methods of in situ transmission electron microscope to study resistive random access memory.

Resistive random access memory (RRAM) devices have been demonstrated to be a promising solution for the implementation of a neuromorphic system with high-density synapses due to the simple device structure, nanoscale dimension, high switching speed, and low power consumption. Various electrical stimuli applied to RRAM devices could cause various working modes of the bionic synapses. The application of RRAM devices needs to understand the micromechanism of the resistive switching process, which is inseparable from advanced characterization techniques. In situ transmission electron microscopy (TEM) with high-resolution imaging and versatile external fields plays an important role in the static characterization and dynamic manipulation of nanoscale devices. Focused on in situ TEM techniques, this review article introduces in situ TEM setups and the corresponding sample fabrication process for RRAM research. Then, the electrical stimulating methodologies including pulse and direct current voltage applied to RRAM are introduced, followed by the summary of electron holography to characterize the electrical potential distribution. By applying various electrical stimuli to the RRAM samples, the working mode of bionic synapses could be changed according to the requirement. Finally, the outlook of the RRAM study with in situ TEM is proposed. This review demonstrates the electrical stimulus capability of in situ TEM to understand the physical mechanism of various types of RRAM devices.

Tailoring atomic 1T phase CrTe2forin situfabrication.

Controllable tailoring and understanding the phase-structure relationship of the 1T phase two-dimensional (2D) materials are critical for their applications in nanodevices. Thein situtransmission electron microscope (TEM) could regulate and monitor the evolution process of the nanostructure of 2D material with atomic resolution. In this work, a controllably tailoring 1T-CrTe2nanopore is carried out by thein situTEM. A preferred formation of the 1T-CrTe2border structure and nanopore healing process are studied at the atomic scale. The controllable tailoring of the 1T phase nanopore could be achieved by regulating the transformation of two types of low indices of crystal faces {101¯0} and {112¯0} at the nanopore border. Machine learning is applied to automatically process the TEM images with high efficiency. By adopting the deep-learning-based image segmentation method and augmenting the TEM images specifically, the nanopore of the TEM image could be automatically identified and the evaluation result of DICE metric reaches 93.17% on test set. This work presents the unique structure evolution of 1T phase 2D material and the computer aided high efficiency TEM data analysis based on deep learning. The techniques applied in this work could be generalized to other materials for controlled nanostructure regulation and automatic TEM image analyzation.

Ferromagnetic CoSe broadband photodetector at room temperature.

Broadband infrared photodetectors based on two-dimensional (2D) materials which are the research focus in the infrared field, have wide applications in remote sensing, thermal imaging, and astronomy observation. In this article, the photodetector based on 2D ferromagnetic material CoSe is studied at room temperature, demonstrating the air-stable, broadband, and up to long wavelength properties. The CoSe material is applied to infrared photodetectors for the first time. The 2D material CoSe is synthesized by using the chemical vapor deposition method. The size of the as-grown CoSe is up to 71.8 µm. The photoresponse of the CoSe photodetector ranges from 450 nm to 10.6 µm. The photoresponsivity of this photodetector is up to 2.58 A W-1 under the 10.6 µm illumination at room temperature. This work provides a new material for broadband photodetector at room temperature and builds a bridge for the magnetoelectronic and broadband photoelectric fields.

Cooperation moderates the impact of effort on reward valuation.

Effort is valuable, but researchers have different opinions on whether effort can reduce or increase the valuation of rewards. The effect of cooperation on reward valuation also remains unclear. In this study, we conducted two experiments to examine the effect of effort on reward valuation (Experiment 1) and whether this effect can be influenced by cooperation (Experiment 2), using electroencephalogram (EEG) technology. We found that when participants worked alone, they generated a larger feedback-related negativity (FRN) amplitude for losing rewards than for gaining rewards, with more effort resulting in larger FRN amplitudes for losing rewards. However, when participants worked together with a partner, there was no significant difference between the amplitude for gaining rewards and that for losing rewards during low-effort tasks. Nevertheless, for high-effort tasks, the FRN amplitude for losing rewards was significantly larger than that for gaining rewards. Moreover, in both experiments, we found larger N1 amplitudes for gaining rewards than for losing rewards. Our ERP results suggest that in the early stage of processing, people pay extra attention to rewards, after that the effort level influences their reward valuation. In addition, cooperation regulates the reduced valuation of losing rewards only when people invest low effort.

Taking Familiar Others' Perspectives to Regulate Our Own Emotion: An Event-Related Potential Study.

Current research on emotion regulation has mainly focused on Gross's cognitive strategies for regulating negative emotion; however, little attention has been paid to whether social cognitive processes can be used to regulate both positive and negative emotions. We considered perspective-taking as an aspect of social cognition, and investigated whether it would affect one's own emotional response. The present study used a block paradigm and event-related potential (ERP) technology to explore this question. A 3 (perspective: self vs. pessimistic familiar other vs. optimistic familiar other) × 3 (valence: positive vs. neutral vs. negative) within-group design was employed. Thirty-six college students participated and considered their own or target others' feelings about pictures with different valences. Results showed that positive emotional responses were more neutral under a pessimistic familiar other perspective, and more positive under an optimistic familiar other perspective, and vice versa for negative emotional responses. In ERP results, compared with a self-perspective, taking familiar others' perspectives elicited reductions in P3 (370-410 ms) and LPP (400-800 ms) difference waves. These findings suggested that taking a pessimistic or optimistic familiar other perspective affects emotion regulation by changing later processing of emotional information.

Identification and transformation difficulty in problem solving: Electrophysiological evidence from chunk decomposition.

A wealth of studies have investigated how to overcome experience-based constraints in creative problem solving. One such experience-based constraint is the tendency for people to view tightly organized visual stimuli as single, unified percepts, even when decomposition of those stimuli into component parts (termed chunk decomposition) would facilitate problem solving. The current study investigates the neural underpinnings of chunk decomposition in creative problem solving by analyzing event-related potentials. In two experiments, participants decomposed Chinese characters into the character's component elements and then used the base elements to form a new valid character. The action could require decomposing a "tight" chunk, meaning that the component elements intersected spatially, or a "loose" chunk, in which the component elements did not overlap in space. Behaviorally, individuals made more errors and responded slower to trials involving tight chunks relative to loose chunks. Analysis of the ERPs revealed that relative to loose chunks, the electrophysiological response to tight chunks contained an increased N2, an increased N400, and a decreased late positive complex. Taken together, these results suggest that chunk tightness is a principle determinant of the difficulty of chunk decomposition, and that chunk tightness provokes neural conflict and semantic violations, factors known to influence the N2 and N400 ERP components.

Raman Characterization on Two-Dimensional Materials-Based Thermoelectricity.

The emergence and development of two-dimensional (2D) materials has provided a new direction for enhancing the thermoelectric (TE) performance due to their unique structural, physical and chemical properties. However, the TE performance measurement of 2D materials is a long-standing challenge owing to the experimental difficulties of precise control in samples and high demand in apparatus. Until now, there is no universal methodology for measuring the dimensionless TE figure of merit (ZT) (the core parameter for evaluating TE performance) of 2D materials systematically in experiments. Raman spectroscopy, with its rapid and nondestructive properties for probing samples, is undoubtedly a powerful tool for characterizing 2D materials as it is known as a spectroscopic 'Swiss-Army Knife'. Raman spectroscopy can be employed to measure the thermal conductivity of 2D materials and expected to be a systematic method in evaluating TE performance, boosting the development of thermoelectricity. In this review, thermoelectricity, 2D materials, and Raman techniques, as well as thermal conductivity measurements of 2D materials by Raman spectroscopy are introduced. The prospects of obtaining ZT and testing the TE performance of 2D materials by Raman spectroscopy in the future are also discussed.

Probing and Manipulating the Interfacial Defects of InGaAs Dual-Layer Metal Oxides at the Atomic Scale.

The interface between III-V and metal-oxide-semiconductor materials plays a central role in the operation of high-speed electronic devices, such as transistors and light-emitting diodes. The high-speed property gives the light-emitting diodes a high response speed and low dark current, and they are widely used in communications, infrared remote sensing, optical detection, and other fields. The rational design of high-performance devices requires a detailed understanding of the electronic structure at this interface; however, this understanding remains a challenge, given the complex nature of surface interactions and the dynamic relationship between the morphology evolution and electronic structures. Herein, in situ transmission electron microscopy is used to probe and manipulate the structural and electrical properties of ZrO2 films on Al2 O3 and InGaAs substrate at the atomic scale. Interfacial defects resulting from the spillover of the oxygen-atom conduction-band wavefunctions are resolved. This study unearths the fundamental defect-driven interfacial electric structure of III-V semiconductor materials and paves the way to future high-speed and high-reliability devices.

In Situ Transmission Electron Microscopy Characterization and Manipulation of Two-Dimensional Layered Materials beyond Graphene.

Two-dimensional (2D) ultra-thin materials beyond graphene with rich physical properties and unique layered structures are promising for applications in electronics, chemistry, energy, and bioscience, etc. The interaction mechanisms among the structures, chemical compositions and physical properties of 2D layered materials are critical for fundamental nanosciences and the practical fabrication of next-generation nanodevices. Transmission electron microscopy (TEM), with its high spatial resolution and versatile external fields, is undoubtedly a powerful tool for the static characterization and dynamic manipulation of nanomaterials and nanodevices at the atomic scale. The rapid development of thin-film and precision microelectromechanical systems (MEMS) techniques allows 2D layered materials and nanodevices to be probed and engineered inside TEM under external stimuli such as thermal, electrical, mechanical, liquid/gas environmental, optical, and magnetic fields at the nanoscale. Such advanced technologies leverage the traditional static TEM characterization into an in situ and interactive manipulation of 2D layered materials without sacrificing the resolution or the high vacuum chamber environment, facilitating exploration of the intrinsic structure-property relationship of 2D layered materials. In this Review, the dynamic properties tailored and observed by the most advanced and unprecedented in situ TEM technology are introduced. The challenges in spatial, time and energy resolution are discussed also.

Identification of bundle sheath cell fate factors provides new tools for C3-to-C4 engineering.

Spatial compartmentation of the photosynthetic process between bundle sheath (BS) cells and mesophyll cells is one of the features that increase the productivity of C4 plants. To introduce C photosynthesis into C3 plants therefore calls for the identification of factors that control BS cell fate and promoter sequences that confer gene expression specifically in the BS and mesophyll cells. We recently demonstrated that three GRAS family transcription factors, SHORT-ROOT (SHR), SCARECROW (SCR) and SCR-LIKE 23 (SCL 23), are required for BS cell fate specification in Arabidopsis thaliana. Homologs to these genes are present in other plant species, C3 and C4, suggesting a conserved mechanism for BS cell fate specification. Interestingly, initially SCR and SCL23 are expressed uniformly in BS cells, but at later stages of leaf development SCR expression becomes restricted to the BS cells associated with the phloem, whereas SCL23 is preferentially expressed in the BS cells abutting the xylem. Characterization of the functions and expression patterns of SHR, SCR and SCL23 homologs in other plants, especially C3 crops, will not only advance the knowledge about BS cell development but also provide new tools for manipulating the number and physiology of BS cells, a critical prerequisite for C3-to-C4 engineering.

Increasing nitric oxide content in Arabidopsis thaliana by expressing rat neuronal nitric oxide synthase resulted in enhanced stress tolerance.

Nitric oxide (NO) plays essential roles in many physiological and developmental processes in plants, including biotic and abiotic stresses, which have adverse effects on agricultural production. However, due to the lack of findings regarding nitric oxide synthase (NOS), many difficulties arise in investigating the physiological roles of NO in vivo and thus its utilization for genetic engineering. Here, to explore the possibility of manipulating the endogenous NO level, rat neuronal NOS (nNOS) was expressed in Arabidopsis thaliana. The 35S::nNOS plants showed higher NOS activity and accumulation of NO using the fluorescent probe 3-amino, 4-aminomethyl-2', 7'-difluorescein, diacetate (DAF-FM DA) assay and the hemoglobin assay. Compared with the wild type, the 35S::nNOS plants displayed improved salt and drought tolerance, which was further confirmed by changes in physiological parameters including reduced water loss rate, reduced stomatal aperture, and altered proline and malondialdehyde content. Quantitative real-time PCR analyses revealed that the expression of several stress-regulated genes was up-regulated in the transgenic lines. Furthermore, the transgenic lines also showed enhanced disease resistance against Pseudomonas syringae pv. tomato (Pst) DC3000 by activating the expression of defense-related genes. In addition, we found that the 35S::nNOS lines flowered late by regulating the expression of CO, FLC and LFY genes. Together, these results demonstrated that it is a useful strategy to exploit the roles of plant NO in various processes by the expression of rat nNOS. The approach may also be useful for genetic engineering of crops with increased environmental adaptations.