Amplitude Of Fluctuations Research Articles

Brain functional alternation in patients with systemic sclerosis: a resting-state functional magnetic resonance imaging study

BackgroundNeuropsychiatric manifestations, such as cognitive impairment, are relatively prevalent in systemic sclerosis (SSc) patients. This study aimed to investigate the resting state (RS) functional alternations of SSc patients and the potential influenced factors.MethodsForty-four SSc patients (mean age, 46.3 ± 11.4 years; 40 females) and 19 age and sex comparable healthy volunteers (mean age, 42.6 ± 11.3 years; 16 females) were recruited and underwent RS functional MR imaging (fMRI) and neuropsychological assessments. Functional segregation analysis was performed to calculate the amplitude of low frequency fluctuation (ALFF) and regional homogeneity (ReHo). Functional integration analysis was conducted using group independent component analysis to calculate intra-network and inter-network functional connectivity (FC). The fMRI measurements were compared between SSc patients and healthy volunteers using voxel-based pairwise two-sample t-tests. The correlations between clinical characteristics and fMRI measurements were also analyzed.ResultsCompared to healthy volunteers, SSc patients exhibited significantly decreased ALFF and increased ReHo (all P < 0.01, FWE corrected). SSc patients predominantly showed decreased intra-network and inter-network FC in the auditory network, visual network, default mode network, frontoparietal network and attention network (intra-network FC: P < 0.01, uncorrected, cluster size > 30; inter-network FC: P < 0.05, FDR correction). Furthermore, clinical characteristics including disease duration (r value ranged from − 0.31 to 0.36), elevated erythrocyte sedimentation rate (r = 0.35), Montreal Cognitive Assessment score (r = 0.43), and Hamilton Depression Scale score (r = -0.40) were significantly associated with fMRI measurements (all P < 0.05).ConclusionsSpontaneous activity and functional connectivity alternations can be seen in SSc patients, which are partially associated with neuropsychiatric manifestations and tend to aggravate with disease duration.

Disentangling the Complex Effects of Seasonal Drought, Floor Mass, and Roots on Soil Microbial Biomass in a Subtropical Moist Forest

Severe seasonal droughts driven by global climate change significantly alter the cycling of carbon and nutrients in forest ecosystems, while the investigation into the impacts of floor mass and plant roots on soil microbial biomass within the context of recurrent seasonal droughts is still rare. To investigate the environmental determinants governing soil microbial biomass with the escalating severity of seasonal droughts, we conducted a study in a montane subtropical moist evergreen broad-leaved forest in southwestern China from June 2019 to May 2023. The study results revealed that soil microbial biomass, as well as soil moisture, floor mass, and plant roots, showed an apparent single-hump modal within one year. In the comparative analysis of the soil microbial biomass fluctuation amplitudes across control and watered plots, a discernible disparity was observed, indicating significant differences in microbial biomass dynamics between the respective experimental conditions. The pooled data revealed a statistically significant influence of seasonal drought, floor mass, plant roots, and their reciprocal interactions on the soil microbial biomass, highlighting these factors as pivotal determinants of microbial community dynamics. This study elucidates the interactive regulatory mechanisms by which seasonal drought, floor mass, and plant roots collectively modulate soil microbial biomass within tropical and subtropical forests, offering insights into the complex ecological processes governing microbial community dynamics. This interactive regulation might influence the trajectory of plant species and soil microbial communities, facilitating their adaptive development and evolutionary responses.

Analysis of the traction forces of two adjacent linear induction motors

Linear induction motors (LIMs) are positioned head-to-tail in medium and low-speed maglev (MLSM) trains, and the interaction due to small spacing between two LIMs is not yet clear. In this work, based on the 2D electromagnetic field theory, the vector magnetic potential (VMP) of each region was solved, and the traction forces of two adjacent LIMs were derived. Subsequently, the correctness of the theoretical model was verified by simulation. Finally, the effects of the spacing, wiring type, pole pitch, speed, etc., on the traction forces of two adjacent LIMs were analyzed. The results show that the traction force of LIM1 (arranged in front) is almost unaffected by LIM2 (arranged behind LIM1), while that of LIM2 fluctuates periodically with the spacing, and the smaller the spacing, the greater the fluctuation amplitude. Meanwhile, the larger the pole pitch, the more the pole number, the greater the slip frequency, and the lower the speed, the smaller the effect of LIM1 on LIM2. When the spacing takes 1.1 to 1.6 times the pole pitch, the traction force of LIM2 is larger than that of LIM1. The achievements can provide technical support for enhancing the traction performance of the LIMs in the MLSM trains.

Hovering Control on a Variable-Parameters Model of a Small Unmanned Helicopter Based on a Backstepping Sliding Mode Method

In order to strengthen the hovering precision of a small unmanned helicopter with a manipulator for completing a hovering operation, in this study, a double-loop control strategy of position and attitude is designed. In the position loop, a sliding mode controller is proposed. It attains high precision and strong robustness under continuous disturbance. With the manipulator continuously operating during helicopter hovering, the overall center of gravity and the moment of inertia of the system will also change. Therefore, a backstepping sliding mode controller is proposed in the attitude loop for controlling the hovering attitude of the helicopter. The high precision and strong robustness of the control system are proven. The digital simulation presents a position steady-state error of less than 2% under constant disturbance, and the hovering attitude angle fluctuation amplitude of the helicopter is less than 0.05 rad.

Potential of accelerometer tags for monitoring of Japanese quail (Coturnix japonica) reproductive behaviour

ABSTRACT 1. Monitoring behavioural dynamics in complex animal environments, such as poultry breeding facilities, poses a challenge. Utilising technological approaches, such as accelerometers, offers a solution to assess long-term changes in reproductive activity at an individual bird level. Specifically, these sensors measure acceleration associated with the position and movements of the body over time. However, it is important to assess the most suitable method for attaching accelerometer tags to ensure they do not negatively impact behaviour and yield high-quality data. 2. The potential of tri-axial accelerometer tags for assessing reproductive behaviour in Japanese quail was evaluated. Two attachment methods – a backpack (plastic platform with elastic bands near wing bases) and a patch (accelerometer on fabric glued to the synsacrum region) – were compared. Controls were handled similarly but without tags. Eighteen pairs of females were housed in pens and assessed immediately and 24 h after handling. After a week of habituation, a male from the same treatment group was introduced into each pen on d 8. The reproductive behaviour of the males was recorded using accelerometers and video recordings. 3. The results showed that birds with patches were able to remove their conspecific’s accelerometer and displayed an increased initial immobility response compared to the control and backpack groups. The presence of accelerometer tags did not impact male/female reproductive interactions nor fear responses to a novel object. From accelerometer recordings, male reproductive behaviour was easily identified as high amplitude fluctuations in the three axial components of the acceleration vectors, which was reflected as large values of dynamic body acceleration (VeDBA). 4. In conclusion, the use of backpacks with accelerometers is a useful strategy to address highly relevant and difficult to tackle behavioural topics such as the temporal dynamic of male reproductive behaviour within breeding groups.

A Multivariable Study of a Traveling Ionosphere Disturbance Using the Arecibo Incoherent Scatter Radar

We present the first simultaneous observations of a traveling ionosphere wave (TID) event, measuring electron concentration (Ne), vertical plasma drift (Vz), and ion and electron temperatures (Ti, Te) using the Arecibo incoherent scatter radar. A TID with a period of 135 min was evident in all four state variables in the thermosphere. The amplitudes of Vz and relative Ti fluctuations show only small height variations from 200 to 500 km and their vertical wavelengths increase with altitude. The Te fluctuation shows different characteristics from EISCAT in both phase and amplitude. When the geomagnetic dip angle is 45°, half of the driving gravity wave’s (GW’s) equatorward velocity is mapped to Vz. This meridional-to-vertical velocity coupling amplifies GW’s effect in Ne through vertical transport. The amplifying and anisotropic effects of the geomagnetic field explain the ubiquitous presence of TIDs and their preferred equatorward propagation direction in the geomagnetic mid-latitudes, as well as the midnight collapse phenomenon observed at Arecibo.

Altered Resting-State Brain Activity of the Superior Parietal Cortex and Striatum in Major Depressive Disorder and Schizophrenia

BackgroundResting-state functional magnetic resonance imaging (fMRI) studies have shown altered brain activity in major depressive disorder (MDD) and schizophrenia (SZ). Despite differing diagnoses, SZ and MDD share similar features. However, functional brain activity similarities and differences between SZ and MDD remain unclear. MethodsParticipants with MDD, SZ, and normal controls (n=36 each) underwent resting-state fMRI scans. Amplitude of low-frequency fluctuations (ALFF) was used to analyze the preprocessed rs-fMRI data. One-way ANOVAs and post hoc analyses compared ALFF values in different brain regions. Pearson correlation analysis examined associations with clinical symptoms. ResultsComparison among the three groups revealed significant differences in ALFF values within the left superior parietal cortex (L-SPC) and bilateral striatum. Through pairwise comparisons, patients with SZ but not patients with MDD were found to exhibit increased striatum ALFF values relative to NC individuals, but decreased in MDD. Meanwhile, L-SPC ALFF values were significantly increased in patients with SZ relative to both normal control individuals and patients with MDD, while no differences in these values were observed between the normal control and MDD groups. The Pearson correlation analyses showed significant positive correlations between ALFF in the striatum and PANSS positive score, but no significant correlation with other symptom severity in SZ and MDD. ConclusionThese findings support the hypothesis of alterations in brain functional activity as a fundamental component of the pathogenesis of MDD and SZ. The observed differences in functional brain activity in the superior parietal cortex and striatum between MDD and SZ provide a neuroimaging basis that can contribute to the differential diagnosis of these debilitating conditions.

Identification of flow patterns in an opaque condenser tube by distributed fiber Bragg gratings

Two-phase loops with phase change heat transfer are pivotal for cooling electronics under high heat flux and for thermal control in spacecraft. Numerous studies aim to clarify the mechanisms behind these loops to enhance cooling capacity and stability, which are closely tied to flow patterns. However, conventional flow pattern identification methods, requiring transparent tubes for direct observation, are impractical for simultaneous heat transfer measurement, especially during condensation. This paper introduces a novel approach for identifying flow patterns within an opaque, vertical condensation tube using embedded distributed fiber Bragg gratings (DFBGs) for R134a. The method involves a “fingerprint” derived from temperature profile derivatives and additional criteria based on temperature variation characteristics. These include the relative deviation from saturation temperature, the relative spatial temperature gradients, and the relative amplitude of temperature fluctuations. Validation against high-speed camera images confirms the method’s efficacy. It enables the determination of flow pattern lengths, the endpoint of condensation, and the construction of a flow regime map. Additionally, it allows for the measurement of vapor velocity in slug flow, facilitating the calculation of slip ratio and void fraction, which correlates reasonably with the Zuber-Findlay model, with systematic positive deviations up to 30%. This method also paves the way for simultaneous measurement of in-tube condensation heat transfer characteristics for various flow patterns.

Resting-State Functional Magnetic Resonance Imaging Reveals the Effects of rTMS on Neural Activity and Brain Connectivity After Experimental Stroke.

Limited understanding of neurobiological mechanisms of repetitive transcranial magnetic stimulation (rTMS) prevents us from choosing optimal therapeutic regimen for patients to improve therapeutic efficiency. Resting-state functional magnetic resonance imaging (rs-fMRI) has been demonstrated to obtain comparable functional readouts across species. Intermittent and continuous theta burst stimulation were used to stimulate ipsilesional and contralesional hemisphere, respectively, during the subacute phase after stroke. We used a rat middle cerebral artery occlusion stroke model. The amplitude of low-frequency fluctuations and functional connectivity analyses of rs-fMRI were chosen to detect neuron activity and functional connectivity. The expression of neuron activation marker c-Fos and axonal plasticity marker GAP43 was examined by an immunochemistry method to corroborate the results of rs-fMRI. iTBS altered the long-term neuronal activity in bilateral sensorimotor cortex, whereas cTBS influenced immediate neuronal activity of bilateral sensorimotor cortex. In addition, cTBS enhanced interhemispheric and intrahemisheric functional connectivity in contralesional hemisphere, accompanied by axonal and dendritic remodeling in the perilesional cortical areas and contralesional homologous areas after large stroke. rTMS exerted complex effects on brain structural and functional connectivity in addition to affecting cortical excitability. cTBS promoted the compensatory effect of contralesional hemisphere after stroke with large lesions.

Leaning against the wind in the New Keynesian model with heterogeneous expectations

In this paper, we explore the efficiency of the Leaning Against the Wind (LAW) policy within the New Keynesian framework with heterogeneous expectations. To do this, we add a financial sector to the model, linking it with the real sector via the financial accelerator channel. We find that the range of parameters in the Taylor rule that enable the stability of the targeted equilibrium is reduced with the financial accelerator. However, expanding the Taylor rule via the LAW policy fails to counteract this effect and may even exacerbate it if the policy reacts to any mispricing. If applied conditionally on high mispricing, the LAW policy leads to co-existing stable targeted and non-targeted equilibria. Our simulations suggest that while the LAW policy can reduce the amplitude of endogenous fluctuations, it is inefficient in dealing with exogenous shocks and results in larger average deviations from the target.

Study on the Spatio-temporal Evolutionary Properties of Gas-liquid Two-phase Flow in Centrifugal Pump as Turbine (PAT)

With the increasing complexity of the industrial production process, the transmission medium of the hydraulic turbine is no longer satisfied, and the gas-liquid two-phase mixed medium has to be considered. The presence of gas in the transmission medium will alters the internal flow structure of the hydraulic turbine and affect its operational stability. Therefore, for the purpose of clarifying the influence of inlet gas content on the internal flow of PAT, the unsteady flow of the PAT is simulated in this paper using numerical simulation. Based on the numerical simulation results, the influence of inlet gas content on the internal flow characteristics, characteristics of pressure fluctuation in impeller and volute, and vortex evolution of flow field are analyzed. The accumulation of gas phase leads to the emergence of vortices, and regions with low pressure values appear at the vortex generation. The major factor of the periodic variation of pressure fluctuation between volute and cut-water is the dynamic and static interference of impeller. The increase of gas content causes more flow disorder in the cut-water region and the volute contraction section. Since the gas in the flow channel is predominantly on the suction side of blades, the flow field on the suction side is more complex than that on the pressure side, and the amplitude of pressure fluctuation increases appropriately. The vortex structure is mainly distributed on balance hole, inlet area of impeller and suction side of blade. As the blade rotates, there are new shedding and growth of vortices, and finally attached to the volute wall. Increasing gas content enhances the influence of blade rotation on the vortex evolution characteristics in the volute and impeller.

Modeling PFAS Subsurface Transport in the Presence of Groundwater Table Fluctuations: The Impact on Source‐Zone Leaching and Exploration of Model Simplifications

AbstractAir–water interfacial adsorption represents a major source of retention for many per‐ and poly‐fluoroalkyl substances (PFAS). Therefore, transient hydrological fluxes that dynamically change the amount of air–water interfaces are expected to strongly influence PFAS retention in their source zones in the vadose zone. We employ mathematical modeling to study how seasonal groundwater table (GWT) fluctuations affect PFAS source‐zone leaching. The results suggest that, by periodically collapsing air–water interfaces, seasonal GWT fluctuations can lead to strong temporal variations in groundwater concentration and significantly enhance PFAS leaching in the vadose zone. The enhanced leaching is more pronounced for longer‐chain PFAS, coarser‐textured porous media, drier climates, and greater amplitudes of fluctuations. GWT fluctuations and lateral migration above the GWT introduce a downgradient persistent secondary source zone for longer‐chain PFAS. However, the enhanced leaching and the secondary source zone are greatly reduced when subsurface heterogeneity is present. In highly heterogeneous source zones, GWT fluctuations may even lead to overall slower leaching due to lateral flow (in the GWT fluctuation zone and above the GWT) moving PFAS into local regions with greater retention capacities. Model simplification analyses suggest that the enhanced source‐zone leaching due to GWT fluctuations may be approximated using a static but shallower GWT. Additionally, while vertical 1D models underestimate source‐zone leaching due to not representing lateral migration, they can be revised to account for lateral migration and provide lower‐ and upper‐bound estimates of PFAS source‐zone leaching under GWT fluctuations. Overall, our study suggests that representing GWT fluctuations is critical for quantifying source‐zone leaching of PFAS, especially the more interfacially active longer‐chain compounds.

Influence of atmospheric turbulence on the spectral composition of the radio signal

Background. It is shown that it is necessary to study the effect of atmospheric turbulence on the spectral characteristics of a radio signal. Aim. The influence of atmospheric turbulence on the spectral fluctuations of the radio signal intensity and on the displacement of the spectral components of the radio signal has been studied. Methods. The research was carried out on the basis of an analysis of the relationship between two-wave and single-wave correlation ratios. Based on the solution of the differential equation for fluctuations of the eikonal amplitude of an electromagnetic wave and the use of the derived trigonometric ratio, a connection between the two-wave Fourier=spectrum and single-wave spectra is obtained. In this case, a single source of turbulence effects on the radio signal was used at the coordinate point of the radio wave propagation by introducing a new variable equal to the average value of the coordinates of the turbulence effect. To find the resulting double integral, one of the coordinates of the turbulent action is transformed into an angular variable. Results. The dependence of the relative dimensionless mean of square of the integral intensity of the radio signal fluctuations on the wave number of turbulent pulsations of the atmosphere at various displacements of the spectral wavelengths of the radio signal is found. Conclusion. It is shown that turbulence slightly distorts the spectral information essence of a propagating radio signal in various wavelength ranges.

Multimodal MRI changes associated with non-motor symptoms of rapid eye movement sleep behaviour disorder in Parkinson's disease patients.

Parkinson's disease (PD), a prevalent neurodegenerative disorder, assumes a more adverse prognosis when accompanied by rapid eye movement sleep disorder (RBD). Non-motor symptoms, particularly sleep and emotional disturbances, significantly impair patients' quality of life. This study aimed to investigate the neuroimaging underpinnings of PD-RBD using structural and functional magnetic resonance imaging (MRI) and to explore the associations between these imaging biomarkers and non-motor symptoms. Brain scans were acquired from 33 PD patients without and 21 with probable RBD (PD-pRBD). Comparative analyses were performed to evaluate structural and functional alterations between the two groups. Additionally, the correlations between neuroimaging metrics and clinical assessment scales were assessed. PD-pRBD patients demonstrated more pronounced grey matter atrophy, particularly in the putamen and insula. Functional MRI revealed decreased amplitude of low-frequency fluctuations (ALFF) in the bilateral posterior cingulate cortex and left precuneus of PD-pRBD patients. Furthermore, reduced functional connectivity (FC) was observed in specific regions of the whole brain and within the default mode network (DMN) in PD-pRBD. Notably, a negative correlation was found between mean ALFF values in the left posterior cingulate cortex of PD-pRBD patients and Hamilton Depression Rating Scale scores. PD-pRBD is characterized by more severe grey matter loss and functional MRI abnormalities compared to PD alone. Dysfunction of the posterior cingulate cortex is implicated in more pronounced affective impairments, providing novel insights into the complex pathophysiology of PD-RBD.

Altered intrinsic neural activity and its molecular analyses in first-episode schizophrenia with auditory verbal hallucinations

BackgroundAuditory verbal hallucinations (AVHs) are one of the signature positive symptoms of schizophrenia, affecting a substantial portion of patients with schizophrenia. These hallucinations seriously impact the lives of patients, resulting in a substantial social burden. Recent studies have shown a significant correlation between abnormal local brain activity and the neurobiological mechanisms of AVHs. However, it is not fully clear whether altered intrinsic brain activity in schizophrenia patients with AVHs is correlated with specific neurotransmitter systems.MethodsWe included 50 first-episode, drug-naïve schizophrenia patients with AVHs, 50 patients without AVHs (NAVHs), and 50 age- and sex-matched healthy controls (HCs). The amplitude of low-frequency fluctuation (ALFF) was utilized to explore the altered intrinsic brain activity in the AVH group. Subsequently, we spatially correlated the altered ALFF with neurotransmitter maps using JuSpace.ResultsIn our study, compared to HCs, the AVH group exhibited significantly reduced ALFF in multiple brain regions, mainly including the left precuneus, bilateral supplementary motor areas, bilateral paracentral lobules, bilateral precentral gyri, and bilateral postcentral gyri. The NAVH group showed significantly reduced ALFF in the left inferior occipital gyrus, left calcarine gyrus, and left lingual gyrus compared to HCs. Furthermore, the AVH group showed higher ALFF in the right inferior frontal gyrus compared to the NAVH group. Additionally, these ALFF alterations in the AVH group were closely related to three neurotransmitters, including dopamine, serotonin and norepinephrine.ConclusionWe link neurotransmitters to abnormal intrinsic brain activity in first-episode, drug-naïve schizophrenia patients with AVHs, contributing to a comprehensive understanding of the pathophysiological processes and treatment pathways underlying AVHs.

Pharmacological manipulation of neurotransmitter activity induces disparate effects on cerebral blood flow and resting-state fluctuations

Abstract Functional MRI methods can assess aspects of drug-induced brain response. Resting blood oxygenation level dependent (BOLD) fMRI and arterial spin labeling (ASL) perfusion MRI indirectly measure brain function through the coupling of activity to cerebral blood flow (CBF) and oxygenation but their relative sensitivity has not been directly compared. We assessed changes in resting measures of BOLD and ASL MRI in response to two neurotransmitter modulators: citalopram, a selective serotonin reuptake inhibitor, and alprazolam, a positive allosteric modulator of GABA type A receptor. Thirty healthy subjects were imaged in a placebo-controlled study, with N=20 subjects receiving each treatment as part of an incomplete block design. Time-averaged CBF images from ASL and measures of resting-state fluctuations of BOLD and ASL images were assessed for significant effects. Following acute citalopram administration, analysis of the ASL data showed a reduction in time-averaged regional CBF in regions associated with high levels of 5-HT1A receptor density. In contrast, following alprazolam administration, BOLD amplitude of low frequency fluctuations showed a highly significant and cortically widespread increase, consistent with the distribution of GABA-A receptors. Only a marginal decrease in ASL CBF was detected after alprazolam intake. BOLD and ASL are each sensitive to drugs targeting neurotransmitter systems, but appear to reflect different aspects of neural metabolism and the balance between excitatory and inhibitory activity. Accordingly, their combination may best capture the effects of neurotransmitter modulations, and thus be advantageous for pharmacological MRI studies.

A Tunable and Switchable Multi-Wavelength Erbium-Doped Fiber Ring Laser Enabled by Adjusting the Spectral Fringe Visibility of a Mach-Zehnder Fiber Interferometer

This paper presents a tunable, switchable multi-wavelength emission from an erbium-doped fiber ring laser, enabled by adjusting the spectral fringe visibility of a fiber interferometer filter. The filter is formed with specially designed concatenated tapered fibers to configure a Mach-Zehnder fiber interferometer (MZFI). The laser emission is highly flexible and reconfigurable, allowing for tuning between single- and dual-wavelength operation. The laser can switch sequentially from one up to six wavelengths by fixing the curvature and adjusting the polarization state. The lasing emission is generated over a stable wavelength range between 1559.59 nm and 1563.54 nm, exhibiting an optical signal-to-noise ratio (OSNR) exceeding ~35 dB. The performance of amplitude and wavelength fluctuations were evaluated, indicating an appropriate stability of ~3 dB and a shift less than 0.1 nm within a 45 min period at room temperature. A detailed comparison with the literature is given.

Association between current of injury and intraoperative R wave amplitude fluctuation immediately after active fixation pacing lead implantation

Abstract Background Active fixation lead stability and pacing threshold adequacy are predictable from assessment of current of injury (COI) prevalence. However, time courses of R wave amplitude value immediately after implantation varies despite of COI prevalence. Objective This study aims to clarify whether intraoperative R wave amplitude fluctuation is associated with COI, and the adequacy assessment is possible. Methods Consecutive recipients of active fixation lead implanted to right ventricular (RV) septum from April to November 2023 were enrolled. R wave amplitude values automatically measured by programmer were continuously recorded from immediately after implantation to generator connection. The final R wave amplitude value greater than 4 mV was determined as implantation success. The successful implantation time courses of R wave amplitude value classified into following three types (Figure 1): (1) the Dipper type; R wave amplitude transiently decreases to the bottom value and then increases, (2) the Riser type; R wave amplitude shows a upward trend (no decline) for the first 5 minutes after active fixation, and (3) the other type. The primary outcome was prevalence of favorable amplitude increase defined as the final R wave amplitude value exceeding that of immediately after the active fixation. Results Among 106 of RV lead implantations in 78 consecutive pacemaker recipients, 73 successful implantation records were evaluated (5 missing data and 28 unsuccess implantations). According to the continuous R wave amplitude records, 51 and 19 successful implantation time courses could be classified into the Dipper and Riser types, respectively. In the Dipper type, the median screw-in to bottom time (SBT) was 5 (interquartile range: 5–12) minutes, and then R wave amplitude improved to mean of 1.7 ± 0.6 times higher than the bottom value. The electrogram (EGM) immediately after active fixation showed R wave &amp;lt; COI pattern, and gradually changed to R wave &amp;gt; COI pattern by the withdrawal of COI over time. Among them, 26 implantations showed favorable amplitude increases and significantly shorter SBT than the remaining implantations (6 ± 4 minutes vs. 10 ± 5 minutes, P=0.03). The ROC analysis showed the predictive cut-off value of SBT for favorable amplitude increase was 6 minutes (AUC:0.73, sensitivity:0.81, specificity:0.60). In the Riser type, acceptable R wave amplitude and R wave &amp;gt; COI pattern EGM were consistently recorded, and finally obtained the favorable amplitude increase in all implantations. Conclusion More than 95% of R wave amplitude fluctuation patterns immediately after successful lead implantation could be classified as the Dipper or Riser types. The mechanism might be associated with a competition among R wave amplitude and COI magnitude, and the prediction of favorable R wave amplitude increase might be possible by the EGM patterns obtained immediately after active lead fixation and the subsequent 5–6 minutes of observation.Success implantation time coursesClinical implication

Predictive and Explainable Artificial Intelligence for Neuroimaging Applications

Background: The aim of this review is to highlight the new advance of predictive and explainable artificial intelligence for neuroimaging applications. Methods: Data came from 30 original studies in PubMed with the following search terms: “neuroimaging” (title) together with “machine learning” (title) or ”deep learning” (title). The 30 original studies were eligible according to the following criteria: the participants with the dependent variable of brain image or associated disease; the interventions/comparisons of artificial intelligence; the outcomes of accuracy, the area under the curve (AUC), and/or variable importance; the publication year of 2019 or later; and the publication language of English. Results: The performance outcomes reported were within 58–96 for accuracy (%), 66–97 for sensitivity (%), 76–98 for specificity (%), and 70–98 for the AUC (%). The support vector machine and the convolutional neural network registered the best performance (AUC 98%) for the classifications of low- vs. high-grade glioma and brain conditions, respectively. Likewise, the random forest delivered the best performance (root mean square error 1) for the regression of brain conditions. The following factors were discovered to be major predictors of brain image or associated disease: (demographic) age, education, sex; (health-related) alpha desynchronization, Alzheimer’s disease stage, CD4, depression, distress, mild behavioral impairment, RNA sequencing; (neuroimaging) abnormal amyloid-β, amplitude of low-frequency fluctuation, cortical thickness, functional connectivity, fractal dimension measure, gray matter volume, left amygdala activity, left hippocampal volume, plasma neurofilament light, right cerebellum, regional homogeneity, right middle occipital gyrus, surface area, sub-cortical volume. Conclusion: Predictive and explainable artificial intelligence provide an effective, non-invasive decision support system for neuroimaging applications.

Deciphering the effects of STN DBS on neuropsychiatric fluctuations in Parkinson’s disease

The impact of subthalamic nucleus (STN) deep brain stimulation (DBS) on neuropsychiatric fluctuations in Parkinson´s disease (PD) remains unclear. The Neuropsychiatric Fluctuations Scale (NFS) can help to fill this gap, directly measuring fluctuations between the OFF- and ON-medication conditions. The NFS provides NFS-plus (hyperdopaminergic) and NFS-minus (hypodopaminergic) sub-scores. Based on these, the NFS global scores express the overall magnitude of neuropsychiatric symptoms in both the OFF- and ON-medication states. The total fluctuation score (TFS) represents the difference between ON- vs. OFF-medication NFS global scores, thus assessing fluctuations amplitude. The NFS was used to evaluate changes in neuropsychiatric fluctuations between the OFF- and ON-medication conditions before and 1-year after bilateral STN-DBS in 45 PD patients (32 males; mean age, 61.3 ± 7.2 years; PD duration, 10.2 ± 3.0 years). After surgery, the amplitude of neuropsychiatric fluctuations was significantly reduced (p < 0.001), confirming the efficacy of STN-DBS on these symptoms.