Spatiotemporal Patterns of Adaptation-Induced Slow Oscillations in a Whole-Brain Model of Slow-Wave Sleep

During slow-wave sleep, the brain is in a self-organized regime in which slow oscillations (SOs) between up- and down-states travel across the cortex. While an isolated piece of cortex can produce SOs, the brain-wide propagation of these oscillations are thought to be mediated by the long-range axonal connections. We address the mechanism of how SOs emerge and recruit large parts of the brain using a whole-brain model constructed from empirical connectivity data in which SOs are induced independently in each brain area by a local adaptation mechanism. Using an evolutionary optimization approach, good fits to human resting-state fMRI data and sleep EEG data are found at values of the adaptation strength close to a bifurcation where the model produces a balance between local and global SOs with realistic spatiotemporal statistics. Local oscillations are more frequent, last shorter, and have a lower amplitude. Global oscillations spread as waves of silence across the undirected brain graph, traveling from anterior to posterior regions. These traveling waves are caused by heterogeneities in the brain network in which the connection strengths between brain areas determine which areas transition to a down-state first, and thus initiate traveling waves across the cortex. Our results demonstrate the utility of whole-brain models for explaining the origin of large-scale cortical oscillations and how they are shaped by the connectome.

Altered Processing of Visual Stimuli in Vestibular Migraine Patients Between Attacks: A Combined VEP and sLORETA Study

Objective: Vestibular migraine (VM) is one of the most common causes of recurrent vertigo, but the neural mechanisms that mediate such symptoms remain unknown. Since visual symptoms and photophobia are common clinical features of VM patients, we hypothesized that VM patients have abnormally sensitive low-level visual processing capabilities. This study aimed to investigate cortex abnormalities in VM patients using visual evoked potential (VEP) and standardized low-resolution brain electromagnetic tomography (sLORETA) analysis.Methods: We employed visual stimuli consisting of reversing displays of circular checkerboard patterns to examine “low-level” visual processes. Thirty-three females with VM and 20 healthy control (HC) females underwent VEP testing. VEP components and sLORETA were analyzed.Results: Patients with VM showed significantly lower amplitude and decreased latency of P1 activation compared with HC subjects. Further topographic mapping analysis revealed a group difference in the occipital area around P1 latency. sLORETA analysis was performed in the time frame of the P1 component and showed significantly less activity (deactivation) in VM patients in the frontal, parietal, temporal, limbic, and occipital lobes, as well as sub-lobar regions. The maximum current density difference was in the postcentral gyrus of the parietal lobe. P1 source density differences between HC subjects and VM patients overlapped with the vestibular cortical fields.Conclusion: The significantly abnormal response to visual stimuli indicates altered processing in VM patients. These findings suggest that abnormalities in vestibular cortical fields might be a pathophysiological mechanism of VM.

Vibration response of glass fiber composite multi-layer graded corrugated sandwich panels

Based on the criteria of equal total height and relative density, a series of glass fiber composite multi-layer graded corrugated sandwich panels (MLGCSPs) with different configurations is designed and fabricated by an in-house hot-molding secondary molding method. The effects of arrangement modes, graded corrugated cores and corrugated topologies on the vibration behavior of the present MLGCSPs are comprehensively investigated by the vibration shaker tests. The results reveal that the arrangement modes, graded arrangement and topologies of the corrugated cores all have significant influences on the frequency responses, and vibration reduction of the present MLGCSPs. The arrangement mode II and III generally have significantly higher resonant frequencies and vibration attenuation performance in the low frequency range, but the arrangement mode I shows better vibration reduction and isolation performance in the higher frequency range. It is possible to simultaneously achieve higher fundamental frequency and lower amplitude of the structures by optimizing the arrangement mode and gradient configuration. Subsequently, finite element simulation is carried out to systematically analyze the vibration responses of the composite MLGCSPs with different configurations. The consistency between numerical and experimental results is quite well. Finally, the effects of structural parameters on the vibration characteristics of the present structures are also revealed. Some conclusions are obtained, which can provide some meaningful guidelines for the vibration reduction design of such type of multi-layer structures.

The association between rest-activity rhythms and glycemic markers: the US National Health and Nutrition Examination Survey, 2011-2014

OBJECTIVES Previous studies conducted in mostly homogeneous sociodemographic samples have reported a relationship between weakened and/or disrupted rest-activity patterns and metabolic dysfunction. This study aims to examine rest-activity rhythm characteristics in relation to glycemic markers in a large nationally-representative and diverse sample of American adults. METHODS This study used data from the National Health and Nutrition Examination Survey 2011-2014. Rest-activity characteristics were derived from extended cosine models using 24-hour actigraphy. We used multinomial logistic regression and multiple linear regression models to assess the associations with multiple glycemic markers (i.e., glycated hemoglobin, fasting glucose and insulin, homeostatic model assessment of insulin resistance, and results from the oral glucose tolerance test), and compared the results across different categories of age, gender, race/ethnicity and body-mass index. RESULTS We found that compared to those in the highest quintile of F statistic , a model-fitness measure with higher values indicating a stronger cosine-like pattern of daily activity, participants in the lowest quintile (i.e, those with the weakest rhythmicity) were 2.37 times more likely to be diabetic (OR Q1 vs. Q5 2.37 (95% CI 1.72, 3.26), p-trend <.0001). Similar patterns were observed for other rest-activity characteristics, including lower amplitude (2.44 (1.60, 3.72)), mesor (1.39 (1.01, 1.91)), and amplitude:mesor ratio (2.09 (1.46, 2.99)), and delayed acrophase (1.46 (1.07, 2.00)). Results were consistent for multiple glycemic biomarkers, and across different sociodemographic and BMI groups. CONCLUSIONS Our findings support an association between weakened and/or disrupted rest-activity rhythms and impaired glycemic control among a diverse US population.

Emotional Modulation of Response Inhibition in Adolescents During Acute Suicidal Crisis: Event-Related Potentials in an Emotional Go/NoGo Task

Objectives. Suicide is the second leading cause of adolescent deaths and may be linked to difficulties with inhibitory and emotional processing. This study assessed the neural correlates of cognitive inhibition during emotional processing in adolescents hospitalized for a suicidal crisis. Methods. Event-related potentials were recorded during an emotional Go/NoGo task in 12 adolescents who attempted suicide and 12 age- and sex-matched healthy controls. Results. Compared to the control group, the suicidal group showed significantly reduced positivity at the time of the P3d (difference waveform reflecting NoGo minus Go trials) in response to happy and neutral, but not sad stimuli. For happy stimuli, this group difference was restricted to the right hemisphere. Further analyses indicated that the suicidal group had a reversed pattern of P3 amplitude in response to inhibition, with lower amplitudes in the NoGo compared to the Go conditions. Suicidal symptoms severity strongly correlated with lower amplitude of the P3d in response to neutral faces. Conclusions. These findings provide more insight into inhibition difficulties in adolescents with acute suicidal risk. Interactions between emotional and inhibition processing should be considered when treating acutely suicidal youths.

Using N-Norms for Analyzing Symmetric Protective Electrical Circuits with Triple Modal Reservation

The redundancy of functional blocks and critical assemblies in radio-electronic equipment is among the most widely used techniques for increasing reliability. Complex redundant systems raise the problem of electromagnetic compatibility (EMC). Ignoring EMC requirements can lead to partial or complete REE failures. In this paper, the authors analyze a noise-protective electrical circuit with triple modal reservation (a promising type of cold redundancy). A multilayer stripline is investigated, the conductors of which are symmetrically arranged relative to two planes. On account of the strong electromagnetic coupling, this protective circuit can decompose dangerous ultra-wideband (UWB) interference received at the input of the primary or redundant circuits into unipolar pulses of lower amplitude. Using this approach, due to the symmetry of the conductors, equal decomposition efficiency could be achieved. However, the effect of UWB interference at the input of one of the conductors produces bipolar pulses at the output of the other conductors. In this paper, the authors evaluate the dangers of unipolar and bipolar decomposed pulses and use modal analysis to mathematically determine the polarities and amplitudes of the decomposed pulses at all output nodes for a pseudo-matched structure. By using the quasistatic approach with and without losses, the time responses to a trapezoidal pulse with a total duration of 60 ps, which simulates UWB interference, are obtained. To confirm the results of modal analysis and quasistatic simulation, an experimental study is performed. Using a stroboscopic oscilloscope DSA 8300, the authors obtained a transient response to a step excitation. Then, taking the derivative, the response to a trapezoidal pulse with a total duration of 140 ps was obtained. To analyze the criticality of the decomposed pulses, N-norms are used. In the general case, it is shown that the UWB interference is decomposed into four pulses of lower amplitude. At the same time, the value of each N-norm indicates its significant attenuation. For example, the amplitude of the UWB pulse acting on the input of the reserved conductor decreases by 10.31–8.93 times. Such results numerically demonstrate the high efficiency of the suggested approach when it comes to protecting equipment against UWB interference. It is also shown that the probability of dielectric breakdown and damage to electronic components in redundant circuits is lower than in a primary circuit. This is due to the fact that the value of N3 in the redundant circuit is 2.38 times less than in the primary circuit. However, the results demonstrate that arcing is highly probable both in primary and redundant circuits. Finally, aspects of symmetry/asymmetry in the problem under investigation are emphasized.

The Identification of Electrical Properties of Acupuncture Points for Asthma Diagnosis

The aim of this research is to identify the electrical potential profile on the acupoint betwen healthy people and the patient of asthma. The raw data has taken by recording the electrical potential profile on the acupoints: Feishu, Pishu, and Shenshu from 10 healthy women and the 10 women with asthma attain the age of 20-30 years old based on the second data observation at the Local Government Clinic Kalijudan, Surabaya. Potential profile of the organs were the electrical signals form. It was achieved by the result of electrical potential which was based time recording. Recording time was done for 180 second. The results couldn't be differentiated significantly, so it needs the other signals processing with FFT analyze method with cutting as the data frames. It was done every 5 second. Based on the result of analyzing the amplitude of each frequency group, the significant differences are on the acupoint Shenshu : 0-5 Hz with p= 0.001, on the acupoint Phishu 148-152 Hz with p= 0.010, on the acupoint Feishu for frequency 198-203 Hz with p= 0.004 and on the acuponit Phishu p=0.011, for frequency 348-352 Hz on the acupoint Feishu and Shenshu have both value is p= 0,004 and 398-402 Hz with p=0,009 on the acupoint Phishu. According to the preference, it was found that the electrical potential profile on the acupoints of the healthy people has lower amplitude than the people with asthma. Then, the analyze of electrical potential profile on the acupoints can be used for asthma diagnose.

The Role of Frontal Thrusts in Tsunami Earthquake Generation

ABSTRACT The frontal sections of subduction zones are the source of a poorly understood hazard: “tsunami earthquakes,” which generate larger-than-expected tsunamis given their seismic shaking. Slip on frontal thrusts is considered to be the cause of increased wave heights in these earthquakes, but the impact of this mechanism has thus far not been quantified. Here, we explore how frontal thrust slip can contribute to tsunami wave generation by modeling the resulting seafloor deformation using fault-bend folding theory. We then quantify wave heights in 2D and expected tsunami energies in 3D for both thrust splays (using fault-bend folding) and down-dip décollement ruptures (modeled as elastic). We present an analytical solution for the damping effect of the water column and show that, because the narrow band of seafloor uplift produced by frontal thrust slip is damped, initial tsunami heights and resulting energies are relatively low. Although the geometry of the thrust can modify seafloor deformation, water damping reduces these differences; tsunami energy is generally insensitive to thrust ramp parameters, such as fault dip, geological evolution, sedimentation, and erosion. Tsunami energy depends primarily on three features: décollement depth below the seafloor, water depth, and coseismic slip. Because frontal ruptures of subduction zones include slip on both the frontal thrust and the down-dip décollement, we compare their tsunami energies. We find that thrust ramps generate significantly lower energies than the paired slip on the décollement. Using a case study of the 25 October 2010 Mw 7.8 Mentawai tsunami earthquake, we show that although slip on the décollement and frontal thrust together can generate the required tsunami energy, <10% was contributed by the frontal thrust. Overall, our results demonstrate that the wider, lower amplitude uplift produced by décollement slip must play a dominant role in the tsunami generation process for tsunami earthquakes.

The Sub-Daily Variability of Aerosol Loading and Associated Radiative Forcing Over the Indian Region

The sub-daily variability of aerosols affects the estimates of daily mean aerosol loading. However, large spatial scale estimates of their climate effects are mostly based on snapshots from low orbit satellites that may bias the mean estimate for daily, monthly, or annual timescales. In this study, an attempt is made to estimate the magnitude of such bias based on ground and satellite-based datasets. Using ground-based measurements, we show an apparent asymmetry (of the order of 10–50%) in the sub-daily variability of aerosol loading over the Indian region. For the first time, it is reported that this sub-daily variability has a spatial pattern with an increasing amplitude toward the east of the subcontinent. We also find this variability in aerosol loading is well-captured by the satellites but with a lower amplitude. Our study shows that such differences could alter the annual surface radiative forcing estimates by more than ∼15 W m−2 over this region. We find that NASA’s Modern-Era Retrospective analysis for Research and Applications version 2 (MERRA-2), a state-of-the-art model-based chemical reanalysis, is unable to capture these sub-daily variabilities. This implies that both model and satellite-based radiative forcing estimates for large spatial scales should improve aerosol sub-daily information/variabilities for obtaining reliable radiative forcing estimates.

Type 2 diabetes and cognitive functions in patients with chronic cerebrovascular diseases

Background. Type 2 diabetes (Т2DM) both directly and indirectly impacts the development of morphological and functional changes of the central nervous system. Aim. The study was to determine clinical and neurophysiological patterns of cognitive impairment (CI) in patients with chronic cerebrovascular diseases (CCD) and Т2DM. Materials and methods. We examined 132 patients with CCD. First group included 58 patients without Т2DM aged 64.5 [58; 72], second group 74 patients with CCD and Т2DM 63 [57; 70]. Clinical, neurological, neuropsychological, neurophysiological (cognitive evoked potentials (EP) and neurovisualisation (brain MRI) examination was carried out to all patients. Results. Somatic and neurological characteristics of the patients were similar in both groups with the exception of more distinct metabolic changes in Т2DM patients. Neurovisualisation study of the brain MRI in Т2DM patients revealed more distinct changes in the form of white matter hyperintensity and subarachnoidal spaces enlargement. Neuropsychological examination in patients revealed the reduction of intellectual flexibility, constructive praxis disruption, optical spatial dysfunction and deteoration of delayed word recall. Significant disorders in the way of overall cognitive impairment, lobar dysfunction and impaired verbal associative productivity, proved by statistically lower amplitude and higher latency of P300 EP peak were noted in Т2DM patients. Correlation links were detected: for P300 amplitude and direct and inverse number listing test (r=0.366 and r=0.520; p=0.006 and p0.001 respectively); P300 latency and HbA1c (r=0.32; р0.05) in group 2 and glucose levels in both groups (r=0.30; p0.05); inverse relationship of latency with control functions evaluation (r=-0.34; p=0.008). Conclusion. CCD especially with Т2DM manifests with neurocognitive imbalance, including control functions disruption and are accompanied by neurophysiological and neurovisualistion changes.