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Physiologically evoked neuronal current MRI in a bloodless turtle brain: Detectable or not?

Qingfei Luo, Huo Lu, Hanbing Lu, David Senseman, Keith Worsley, Yihong Yang, Jia-Hong Gao
2009 NeuroImage  
Contradictory results from the efforts for detecting evoked neuronal currents have left the feasibility of neuronal current MRI (ncMRI) an open question. Most of the previous ncMRI studies in human subjects are suspect due to their inability to separate or eliminate the hemodynamic effects. In this study, we used a bloodless turtle brain that eliminates hemodynamic effects, to explore the feasibility of detecting visual-evoked ncMRI signals at 9.4T. The turtle brain, with its eyes attached, was
more » ... dissected from the cranium and placed in artificial cerebral spinal fluid. Light flashes were delivered to the eyes, which produced visual-evoked neuronal activity in the brain. Local field potential (LFP) and MRI signals in the turtle brain were measured in an interleave fashion. Although robust neuronal responses to the visual stimulation were observed in the LFP signals, no significant signal changes synchronized with neuronal currents were found in the MRI images. Analysis of the temporal stability of the MRI time courses indicated that the detectable effect sizes are 0.11% and 0.09° for the magnitude and phase, respectively, and the visual-evoked ncMRI signals in the turtle brain are below these levels. Advances in non-invasive neuroimaging have greatly enhanced our understanding of the functional organization of the human brain. However, limitations remain in current leading neruroimaging methods. EEG and MEG directly measure neuronal electric activity with high temporal resolution, but afford limited spatial resolution and uncertainty of activation location due to the inverse source problem. Functional MRI (fMRI) and PET techniques detect changes in regional hemodynamic and metabolism (blood flow/volume/oxygenation and glucose metabolism) that accompany changes in neuronal activity. However, due to the variation of vasculature and the complex nature of neuronal-hemodynamic coupling, both fMRI and PET techniques are unable to achieve high spatial and temporal accuracy for mapping neuronal activity. To overcome the limitations of present neuroimaging methods, researchers have made efforts to use MRI to measure directly the magnetic fields generated by the neuronal electrical activity, termed neuronal current MRI (ncMRI). Neuronal activity generates changes in ionic currents along neuronal axons and dendrites. The ionic currents produce
doi:10.1016/j.neuroimage.2009.06.017 pmid:19539040 pmcid:PMC3860745 fatcat:442gtlh4kvfaviekb4qbzt5gei

Single-Trial Evoked Potentials Extraction Based on Sparsifying Transforms

Nannan Yu, Qisheng Ding, Hanbing Lu
2015 Journal of Pharmacy and Pharmacology  
Evoked potentials are widely used to diagnose diseases and disorders in the central nervous system. It is thus essential to develop fast algorithms which can track the variations of evoked potentials for a variety of clinical applications. The sparsity of signals in a certain transform domain or dictionary has been exploited in the extraction of noisy signal. However, it isn't effective enough to extract the evoked potentials because the signal-to-noise ratio is extremely low. In this paper, we
more » ... present a novel approach to solving evoked potentials extracting problem. Before the sparsifying the observations of evoked potentials, the observations are transformed to enhance the signal-to-noise ratio and sparsity. Then we can use the sparse representation algorithm to extract the evoked potentials. The alternating minimization algorithms are applied to calculate the transformation matrix and the sparse coefficients. We show the superiority of our approach over some filtering and sparse representation methods.
doi:10.17265/2328-2150/2015.12.003 fatcat:fmnmuk3xs5aw7fjtl7nf6ecp6i

Frequency specificity of functional connectivity in brain networks

Changwei W. Wu, Hong Gu, Hanbing Lu, Elliot A. Stein, Jyh-Horng Chen, Yihong Yang
2008 NeuroImage  
., 1998) , although the exact neurophysiological mechanism of functional connectivity is still under active investigations (Lu et al., 2007; Mantini et al., 2007) .  ...  gamma (γ) band (Niessing et al., 2005; Wilke et al., 2006) , while the restingstate HDR in the rat somatosensory cortex correlates with LFPs in the lower frequency range, particularly in the δ band (Lu  ... 
doi:10.1016/j.neuroimage.2008.05.035 pmid:18632288 pmcid:PMC2612530 fatcat:b5yfhgmkuvbvplxrwlmrtt6n4i

Single-Trial Sparse Representation-Based Approach for VEP Extraction

Nannan Yu, Funian Hu, Dexuan Zou, Qisheng Ding, Hanbing Lu
2016 BioMed Research International  
Sparse representation is a powerful tool in signal denoising, and visual evoked potentials (VEPs) have been proven to have strong sparsity over an appropriate dictionary. Inspired by this idea, we present in this paper a novel sparse representation-based approach to solving the VEP extraction problem. The extraction process is performed in three stages. First, instead of using the mixed signals containing the electroencephalogram (EEG) and VEPs, we utilise an EEG from a previous trial, which
more » ... not contain VEPs, to identify the parameters of the EEG autoregressive (AR) model. Second, instead of the moving average (MA) model, sparse representation is used to model the VEPs in the autoregressive-moving average (ARMA) model. Finally, we calculate the sparse coefficients and derive VEPs by using the AR model. Next, we tested the performance of the proposed algorithm with synthetic and real data, after which we compared the results with that of an AR model with exogenous input modelling and a mixed overcomplete dictionary-based sparse component decomposition method. Utilising the synthetic data, the algorithms are then employed to estimate the latencies of P100 of the VEPs corrupted by added simulated EEG at different signal-to-noise ratio (SNR) values. The validations demonstrate that our method can well preserve the details of the VEPs for latency estimation, even in low SNR environments.
doi:10.1155/2016/8569129 pmid:27807541 pmcid:PMC5078735 fatcat:lr4b36mbarcsrkvhlxf7rd5x6u

Angle-tuned Coil: A Focal Spot-size Adjustable Transcranial Magnetic Stimulator [article]

Qinglei Meng, Hedyeh Bagherzadeh, Julian Loiacono, Xiaoming Du, Elliot Hong, Yihong Yang, Hanbing Lu, Fow-Sen Choa
2019 bioRxiv   pre-print
AbstractBackgroundConventional transcranial magnetic stimulation (TMS) coils are limited by the depth-focality tradeoff rule and the emission field intensity from coils with either small or large apertures will diverge quickly at less than one aperture diameter distance away from the coil. To utilize a better depth-focality tradeoff rule and accomplish deep and focused stimulation, a new approach needs to be employed.ObjectivesWe report a new TMS coil design that can deliver deep and spot size
more » ... djustable stimulation to deep brain regions.MethodsIn our design, we introduce a magnetic core at the center of a coil to help confine the magnetic field and prevent leakage. We further tilted the wire wrapping angle of the coil to break its ring symmetry and accomplish tunable focusing by adjusting the tilting angle.ResultsBy comparing the electric field decay curves of five types of coils, our results concluded the proposed novel method to improve the coils' depth-focality profile. Both theoretical calculations and experimental data collectively demonstrated that by using a larger tilting angle, we were able to accomplish a more tightly focused stimulation at any distance away from the coil.ConclusionEnlarging the tilting angle of the coil wire wrapping and applying magnetic core significantly improved the spatial resolution of the field without inducing considerable effect on field decay speed. Our novel TMS coil design plots a new curve in the depth-focality profile with better performance than the existing conventional coil designs in the tradeoff rule.
doi:10.1101/771758 fatcat:kty2qdr3hzbsfptpl3yhmvp75e

TE-dependent spatial and spectral specificity of functional connectivity

Changwei W. Wu, Hong Gu, Qihong Zou, Hanbing Lu, Elliot A. Stein, Yihong Yang
2012 NeuroImage  
., 2003; Lu et al., 2007; Shmuel and Leopold, 2008) , suggesting that the RS-fMRI signal originates mainly from synchronized neural activity (Varela et al., 2001) .  ...  Lu et al. (2007) also observed that long-distance somatosensory connections in rats were reduced with increasing anesthesia levels, while short-distance connections remained relatively unaffected.  ... 
doi:10.1016/j.neuroimage.2011.11.030 pmid:22119650 pmcid:PMC3408660 fatcat:g4gy5fodcfhhlokwjwcwtpcvse

Pneumocystis Jirovecii Pneumonia Diagnosis via Metagenomic Next-Generation Sequencing

Xiaoxiao Lu, Jianhui Zhang, Wentao Ma, Lihua Xing, Hanbing Ning, Mengying Yao
2022 Frontiers in Medicine  
The incidence of non-HIV-infected Pneumocystis Jirovecii Pneumonia (PJP) is increasing. The prognosis for non-HIV PJP is poor and diagnostic tests are of lower sensitivity in non-HIV patients. Metagenomic next-generation sequencing (mNGS) was compared with routine detection assays, including Gomori methenamine silver (GMS) stain and polymerase chain reaction (PCR) technique. Specimens of 4 bronchoalveolar lavages (BAL) and 1 lung tissue samples were obtained from 4 non-HIV patients from our
more » ... itals. Although both GMS and mNGS were positive for P. jirovecii with PCR as positive control, the testing time of mNGS was obviously shorter than GMS. Compared with the traditional GMS method, mNGS has absolute advantages. However, the issue with PJP presentations having atypical symptoms and ambiguous imaging features persists. Hence, the disease can easily be ignored. Secondly, PJP progresses rapidly in non-HIV-infected patients and can cause severe respiratory failure with unfavorable prognosis. This study affirms that mNGS can be used to quickly and accurately diagnose PJP, but a combination of clinical judgement of symptoms, laboratory testing, and imaging examination is required to make a comprehensive judgment along with mNGS test results.
doi:10.3389/fmed.2022.812005 pmid:35372422 pmcid:PMC8965517 fatcat:ne6rzttwjnduddcabsptx5lomi

A MISO-ARX-Based Method for Single-Trial Evoked Potential Extraction

Nannan Yu, Lingling Wu, Dexuan Zou, Ying Chen, Hanbing Lu
2017 BioMed Research International  
In this paper, we propose a novel method for solving the single-trial evoked potential (EP) estimation problem. In this method, the single-trial EP is considered as a complex containing many components, which may originate from different functional brain sites; these components can be distinguished according to their respective latencies and amplitudes and are extracted simultaneously by multiple-input single-output autoregressive modeling with exogenous input (MISO-ARX). The extraction process
more » ... is performed in three stages: first, we use a reference EP as a template and decompose it into a set of components, which serve as subtemplates for the remaining steps. Then, a dictionary is constructed with these subtemplates, and EPs are preliminarily extracted by sparse coding in order to roughly estimate the latency of each component. Finally, the single-trial measurement is parametrically modeled by MISO-ARX while characterizing spontaneous electroencephalographic activity as an autoregression model driven by white noise and with each component of the EP modeled by autoregressive-moving-average filtering of the subtemplates. Once optimized, all components of the EP can be extracted. Compared with ARX, our method has greater tracking capabilities of specific components of the EP complex as each component is modeled individually in MISO-ARX. We provide exhaustive experimental results to show the effectiveness and feasibility of our method.
doi:10.1155/2017/7395385 pmid:28280739 pmcid:PMC5320388 fatcat:2qdnchrvpncdbpx77hnrrkvzte

An Improved Shuffled Frog-Leaping Algorithm for Flexible Job Shop Scheduling Problem

Kong Lu, Li Ting, Wang Keming, Zhu Hanbing, Takano Makoto, Yu Bin
2015 Algorithms  
The flexible job shop scheduling problem is a well-known combinatorial optimization problem. This paper proposes an improved shuffled frog-leaping algorithm to solve the flexible job shop scheduling problem. The algorithm possesses an adjustment sequence to design the strategy of local searching and an extremal optimization in information exchange. The computational result shows that the proposed algorithm has a powerful search capability in solving the flexible job shop scheduling problem
more » ... red with other heuristic algorithms, such as the genetic algorithm, tabu search and ant colony optimization. Moreover, the results also show that the improved strategies could improve the performance of the algorithm effectively. Keywords: shuffled frog-leaping algorithm; flexible job shop scheduling problem; local search; extremal optimization OPEN ACCESS Algorithms 2015, 8 20 1. Introduction The scheduling of operations has a vital role in the planning and managing of manufacturing processes. The job-shop scheduling problem (JSP) is one of the most popular scheduling models in practice. In the JSP, a set of jobs should be processed with a set of machines, and each job consists of a sequence of consecutive operations. Moreover, a machine can only process one operation at one time, and the operation cannot be interrupted. Additionally, JSP is aimed at minimizing the number of operations for these jobs under the above constraints. The flexible job-shop scheduling problem (FJSP) is an extension of the conventional JSP, in which operations are allowed to be processed on any one of the existed machines. FJSP is more complicated than JSP, because FJSP not only needs to identify the arrangement of all processes of all machines, but also needs to determine the sequence of processes on each machine. FJSP breaks through the uniqueness restriction of resources. Each process can be completed by many different machines, so that the job shop scheduling problem is closer to the real production process. JSP has been proven to be an NP-hard problem [1], and even for a simple instance with only ten operations and ten available machines for selection, it is still hard to search for a convincing result. As an extension of JSP, FJSP is more complicated to solve. A lot of the literature believes that adopting a heuristic method is a reasonable approach for solving this kind of complex problem [2-9]. Thus, there are many researchers who have used heuristic methods to solve FJSP. Brandimarte [10] attempted to use a hierarchical approach to solve the flexible job shop scheduling problem, and a tabu search is adopted to enhance the effectiveness of the approach. Fattahi et al. [11] proposed a mathematical model for the flexible job shop scheduling problem, and two heuristic approaches (tabu search and simulated annealing heuristics) are also introduced to solve the real size problems. Gao et al. [12] developed a hybrid genetic algorithm to solve the flexible job shop scheduling problem. In the algorithm, the two vectors are used to represent the solution, the individuals of GA are improved by a variable neighborhood descent and the advanced genetic operators are presented by a special chromosome structurer. Yao et al. [2] presented an improved ant colony optimization to solve FJSP, and an adaptive parameter, crossover operation and pheromone updating strategy are used to improve the performance of the algorithm. The shuffled frog-leaping algorithm (SFLA) was developed by Eusuff and Lansey [13] . It is a meta-heuristic optimization method, which combines the advantages of the genetic-based memetic algorithm (MA) and the social behavior-based PSO algorithm [14] . A meme is a kind of information body, which can be distributed, reproduced and exchanged by infecting the thoughts of human beings or animals. The most salient characteristic of the meme algorithm is that memes can share and exchange experience, knowledge and information along with relying on a local search method in the process of evolution. Therefore, with the meme algorithm allows an individual of the traditional genetic algorithm model to become more intelligent. The group of SFLA consists of the frog group in which the individual frogs can communicate with each other. Each frog can be seen as a meme carrier. Along with the communication among frogs, the meme evolution can be performed during the searching process of the algorithm. Due to its efficiency and practical value, SFLA has attracted more attention and has been successfully used in a number of classical combinatorial optimization problems [15] [16] [17] [18] [19] .
doi:10.3390/a8010019 fatcat:v3bzf7frevehvkgbcwwvuyeylq

Brain regional synchronous activity predicts tauopathy in 3×TgAD mice

Dong Liu, Hanbing Lu, Elliot Stein, Zhujuan Zhou, Yihong Yang, Mark P. Mattson
2018 Neurobiology of Aging  
while lightly anesthetized using a combination of a low concentration of isoflurane and the α-adrenoreceptor agonist dexmedetomidine (Zoetis, Parisippany, NJ, USA) as previously developed for rat fMRI (Lu  ... 
doi:10.1016/j.neurobiolaging.2018.06.016 pmid:30015035 pmcid:PMC6196326 fatcat:uu7pbddflzgoffbhltqr2ailre

Origins of the Resting-State Functional MRI Signal: Potential Limitations of the "Neurocentric" Model

Hanbing Lu, Saul Jaime, Yihong Yang
2019 Frontiers in Neuroscience  
These results are generally in line with the conclusions from studies in anesthetized rats (Lu et al., 2007 (Lu et al., , 2014 Pan et al., 2010; Magnuson et al., 2014) .  ...  The localized synchrony patterns in homotopic cortical regions recorded using VSD are strikingly similar to rsFC reported in rodent fMRI literature (Lu et al., 2007 (Lu et al., , 2012 Pawela et al., 2008  ... 
doi:10.3389/fnins.2019.01136 pmid:31708731 pmcid:PMC6819315 fatcat:aczqwro3ordwbkjohuhov46m4i

Single-Trial Evoked Potential Estimating Based on Sparse Coding under Impulsive Noise Environment

Nannan Yu, Ying Chen, Lingling Wu, Hanbing Lu
2018 Computational Intelligence and Neuroscience  
Estimating single-trial evoked potentials (EPs) corrupted by the spontaneous electroencephalogram (EEG) can be regarded as signal denoising problem. Sparse coding has significant success in signal denoising and EPs have been proven to have strong sparsity over an appropriate dictionary. In sparse coding, the noise generally is considered to be a Gaussian random process. However, some studies have shown that the background noise in EPs may present an impulsive characteristic which is far from
more » ... ssian but suitable to be modeled by the α-stable distribution 1<α≤2. Consequently, the performances of general sparse coding will degrade or even fail. In view of this, we present a new sparse coding algorithm using p-norm optimization in single-trial EPs estimating. The algorithm can track the underlying EPs corrupted by α-stable distribution noise, trial-by-trial, without the need to estimate the α value. Simulations and experiments on human visual evoked potentials and event-related potentials are carried out to examine the performance of the proposed approach. Experimental results show that the proposed method is effective in estimating single-trial EPs under impulsive noise environment.
doi:10.1155/2018/9672871 pmid:29765400 pmcid:PMC5885402 fatcat:6suwe7kplva35k2m2y56bkb4jm

Palladium-Catalyzed C-H Alkoxycarbonylation of Caffeines: Synthesis of 8-Ester-substituted Caffeines

Lü Su, Hanbing Xiao, Yumeng Yuan, Xiaofeng Zhang, Shen Lin, Qiufeng Huang
2017 Youji huaxue  
doi:10.6023/cjoc201610028 fatcat:smqr6fvyebhavdzv5lwdso64bm

Mapping functional connectivity based on synchronized CMRO2 fluctuations during the resting state

Changwei W. Wu, Hong Gu, Hanbing Lu, Elliot A. Stein, Jyh-Horng Chen, Yihong Yang
2009 NeuroImage  
INTRODUCTION Synchronized low-frequency fluctuations in the resting-state functional MRI (fMRI) signal have been suggested to be associated with functional connectivity in brain networks (1). However, the underlying mechanism of this connectivity is still poorly understood. To better interpret the resting signal, we examined spontaneous fluctuations at the level of cerebral metabolic rate of oxygenation (CMRO 2 ), an index reflecting regional oxygen consumption and metabolism, and thus less
more » ... itive to vascular dynamics. The CMRO 2 signal was determined based on a biophysical model (2) with simultaneously acquired blood oxygenation level dependent (BOLD) and perfusion signals.
doi:10.1016/j.neuroimage.2008.12.066 pmid:19280693 pmcid:PMC2775537 fatcat:725qv4gs4ffb5on6he7hwhpevu

Real-time animal functional magnetic resonance imaging and its application to neuropharmacological studies

Hanbing Lu, Shaolin Yang, Yantao Zuo, Steven Demny, Elliot A. Stein, Yihong Yang
2008 Magnetic Resonance Imaging  
Lu et al. Page 12 Magn Reson Imaging. Author manuscript; available in PMC 2018 May 14. Lu et al. Page 14  ...  Lu Real time assessment of the outcome of BBB disruption following bolus injections of hyperosmolar mannitol. A is a traditional T 1 -weighted spin echo sequence anatomical image.  ... 
doi:10.1016/j.mri.2008.02.020 pmid:18448300 pmcid:PMC5951389 fatcat:s7uaxj6q7jfbnkxsqw4duuetea
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