ABSTRACT
In recent years, exploring the physiological and pathological mechanisms of brain functional integration from the neural network level has become one of the focuses of neuroscience research. Due to the non-stationary and nonlinear characteristics of neural signals, its linear characteristics are not sufficient to fully explain the potential neurophysiological activity mechanism in the implementation of complex brain functions. In order to overcome the limitation that the linear algorithm cannot effectively analyze the nonlinear characteristics of signals, researchers proposed the transfer entropy (TE) algorithm. In recent years, with the introduction of the concept of brain functional network, TE has been continuously optimized as a powerful tool for nonlinear time series multivariate analysis. This paper first introduces the principle of TE algorithm and the research progress of related improved algorithms, discusses and compares their respective characteristics, and then summarizes the application of TE algorithm in the field of electrophysiological signal analysis. Finally, combined with the research progress in recent years, the existing problems of TE are discussed, and the future development direction is prospected.
Subject(s)
Algorithms , Brain/physiology , Entropy , Neural Networks, Computer , Nonlinear DynamicsABSTRACT
Changes in the intrinsic characteristics of brain neural activities can reflect the normality of brain functions. Therefore, reliable and effective signal feature analysis methods play an important role in brain dysfunction and relative diseases early stage diagnosis. Recently, studies have shown that neural signals have nonlinear and multi-scale characteristics. Based on this, researchers have developed the multi-scale entropy (MSE) algorithm, which is considered more effective when analyzing multi-scale nonlinear signals, and is generally used in neuroinformatics. The principles and characteristics of MSE and several improved algorithms base on disadvantages of MSE were introduced in the article. Then, the applications of the MSE algorithm in disease diagnosis, brain function analysis and brain-computer interface were introduced. Finally, the challenges of these algorithms in neural signal analysis will face to and the possible further investigation interests were discussed.
ABSTRACT
With the development of CT and the popularization of health examination, the detection rate of small pulmonary nodules has been improved. Some small pulmonary nodules could be malignant nodules. Surgical resection is the preferred treatment. Therefore, it is an important task for thoracic surgeons to accurately locate pulmonary nodules during surgery and remove nodules accurately on the premise of maximum protection of lung function. At present, the core of preoperative auxiliary localization of pulmonary nodules is the implantation of markers. The commonly used clinical localization methods include hook wire localization, microcoil localization, methylene blue puncture injection localization and biological glue localization. In this paper, the development status, application scope, advantages and disadvantages of existing localization methods are briefly reviewed, which can provide references for clinical application and follow-up research.
ABSTRACT
The possible influence of electromagnetic field (EMF) on the function of neural systems has been widely concerned. In this article, we intend to investigate the effects of long term power frequency EMF exposure on brain cognitive functions and it's mechanism. The Sprague-Dawley (SD) rats were randomly divided into 3 groups: the rats in EMF Ⅰ group were placed in the 2 mT power frequency EMF for 24 days. The rats in EMF Ⅱ group were placed in the 2 mT power frequency EMF for 48 days. The rats in control group were not exposed to the EMF. Then, the 16 channel local field potentials (LFPs) were recorded from rats' prefrontal cortex (PFC) in each group during the working memory (WM) tasks. The causal networks of LFPs were also established by applying the directed transfer function (DTF). Based on that, the differences of behavior and the LFPs network connection patterns between different groups were compared in order to investigate the influence of long term power frequency EMF exposure on working memory. The results showed the rats in the EMF Ⅱ group needed more training to reach the task correction criterion (over 80%). Moreover, the causal network connection strength and the global efficiency of the rats in EMF Ⅰ and EMF Ⅱ groups were significantly lower than the corresponding values of the control group. Meanwhile, significant differences of causal density values were found between EMF Ⅱ group and the other two groups. These results indicate that long term exposure to 2 mT power frequency EMF will reduce the connection strength and the information transfer efficiency of the LFPs causal network in the PFC, as well as the behavior performance of the rats. These results may explain the effect of EMF exposure on working memory from the view of neural network connectivity and provide a support for further studies on the mechanism of the effect of EMF on cognition.
ABSTRACT
Objective To explore the effect of Baihe Zhimu Tang(百合知母汤,BZT) on the airway inflammation in bronchial asthma rats.Methods Forty Wistar rats were randomized into control group,asthma model group,BZT group and dexamethasone (DX) group with 10 rats in each group.The bronchial asthma rat model was built by intraperitoneal injection of 10％ ovalbumin (OVA) and ultrasonic atomizing inhalation of 2％ OVA except for the control group.Thirty minutes before every ultrasonic atomizing inhalation,the BZT group was given BZT 3.68 g/(kg · d) by gastric perfusion;the DX group was administered DX injection 1.2 mg/(kg · d) by gastric perfusion;as for the control group and asthma model group,they were given normal saline of the same volume;all groups were intervened for 14 days.After that,HE staining was used to observe the pathological changes of lung tissue,the levels of interleukin-2 (IL-2) and interleukin-4 (IL-4) were measured,and the cell cycle and calcineurin (CaN) activity were observed in separated peripheral blood lymphocytes.Results For the asthma model group,there was a lot of inflammatory cell infiltration in the bronchial wall under light microscope,the content of IL-4 in the plasma was higher than that in the control group,while the content of IL-2 decreased,the proportion of G0/G1 phase lymphocytes decreased,the proportion of S phase and G2/M increased,and the CaN activity of lymphocytes increased significantly (P ＜ 0.05).For the BZT group,there was only a small amount of inflammatory cell infiltration in the lung tissue under light microscope,the IL-4 level in the plasma was lower than that in the asthma model group,while the IL-2 content increased,the proportion of G0/G1 phase lymphocytes increased,the proportion of S phase and G2/M decreased significantly,and the CaN activity of lymphocytes decreased significantly (P ＜ 0.05).Conclusion BZT could reduce lymphocyte proliferation,decrease IL-4 level and reduce airway inflammation by reducing CaN activity in peripheral blood lymphocytes of bronchial asthma rats.