Study on effects of 40 Hz light flicker stimulation on spatial working memory in rats and its neural mechanism / 生物医学工程学杂志

Alzheimer's disease (AD) is a neurodegenerative disease characterized by cognitive impairment, with the predominant clinical diagnosis of spatial working memory (SWM) deficiency, which seriously affects the physical and mental health of patients. However, the current pharmacological therapies have unsatisfactory cure rates and other problems, so non-pharmacological physical therapies have gradually received widespread attention. Recently, a novel treatment using 40 Hz light flicker stimulation (40 Hz-LFS) to rescue the cognitive function of model animals with AD has made initial progress, but the neurophysiological mechanism remains unclear. Therefore, this paper will explore the potential neural mechanisms underlying the modulation of SWM by 40 Hz-LFS based on cross-frequency coupling (CFC). Ten adult Wistar rats were first subjected to acute LFS at frequencies of 20, 40, and 60 Hz. The entrainment effect of LFS with different frequency on neural oscillations in the hippocampus (HPC) and medial prefrontal cortex (mPFC) was analyzed. The results showed that acute 40 Hz-LFS was able to develop strong entrainment and significantly modulate the oscillation power of the low-frequency gamma (lγ) rhythms. The rats were then randomly divided into experimental and control groups of 5 rats each for a long-term 40 Hz-LFS (7 d). Their SWM function was assessed by a T-maze task, and the CFC changes in the HPC-mPFC circuit were analyzed by phase-amplitude coupling (PAC). The results showed that the behavioral performance of the experimental group was improved and the PAC of θ-lγ rhythm was enhanced, and the difference was statistically significant. The results of this paper suggested that the long-term 40 Hz-LFS effectively improved SWM function in rats, which may be attributed to its enhanced communication of different rhythmic oscillations in the relevant neural circuits. It is expected that the study in this paper will build a foundation for further research on the mechanism of 40 Hz-LFS to improve cognitive function and promote its clinical application in the future.

Effects of 50 Hz electromagnetic field on rat working memory and investigation of neural mechanisms / 生物医学工程学杂志

With the widespread use of electrical equipment, cognitive functions such as working memory (WM) could be severely affected when people are exposed to 50 Hz electromagnetic fields (EMF) for long term. However, the effects of EMF exposure on WM and its neural mechanism remain unclear. In the present paper, 15 rats were randomly assigned to three groups, and exposed to an EMF environment at 50 Hz and 2 mT for a different duration: 0 days (control group), 24 days (experimental group I), and 48 days (experimental group II). Then, their WM function was assessed by the T-maze task. Besides, their local field potential (LFP) in the media prefrontal cortex (mPFC) was recorded by the in vivo multichannel electrophysiological recording system to study the power spectral density (PSD) of θ and γ oscillations and the phase-amplitude coupling (PAC) intensity of θ-γ oscillations during the T-maze task. The results showed that the PSD of θ and γ oscillations decreased in experimental groups I and II, and the PAC intensity between θ and high-frequency γ (hγ) decreased significantly compared to the control group. The number of days needed to meet the task criterion was more in experimental groups I and II than that of control group. The results indicate that long-term exposure to EMF could impair WM function. The possible reason may be the impaired communication between different rhythmic oscillations caused by a decrease in θ-hγ PAC intensity. This paper demonstrates the negative effects of EMF on WM and reveals the potential neural mechanisms from the changes of PAC intensity, which provides important support for further investigation of the biological effects of EMF and its mechanisms.

Research progress and application of transfer entropy algorithm / 生物医学工程学杂志

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.

Clinical application effects of thoracoscopic pulmonary resection assisted with magnetic anchor technique / 西安交通大学学报(医学版)

【Objective】 To investigate the clinical application of self-developed magnetic anchoring device for assisting thoracoscopic pulmonary resection. 【Methods】 Eleven patients underwent thoracoscopic pulmonary assisted with resection magnetic anchoring technique at the Department of Thoracic Surgery, The First Affiliated Hospital of Xi’an Jiaotong University, from March to May 2019. Their clinical data were retrospectively analyzed. The operation time, blood loss, blood transfusion volume, postoperative hospital stay, and postoperative complications were recorded. 【Results】 There were seven male and four female patients, with the average age of (51.6±13.9) years (range from 22 to 69 years). Three single-port and eight single-utility-port thoracoscopic surgeries were performed. Magnetic instruments provided good surgical field exposure in all operations. Among 11 surgeries, one was converted to thoracotomy and one to three-hole surgery due to enlargement and adhesion of hilar lymph nodes. The operation time was (107.8±63.1) minutes (range of 27-182 minutes). The blood loss was 50 (10-50)mL (range of 5-1 000 mL). No blood transfusion was needed during the operation. The postoperative hospital stay was (5.0±1.8) days (range of 3-9 days). No postoperative complications occurred in all the patients. 【Conclusion】 Magnetic anchor technique can effectively alleviate the "chopstick effect" in thoracoscopic surgery. Magnetic anchor technique is safe and feasible in assisting thoracoscopic pulmonary resection.

Progress in localization of pulmonary nodules / 国际外科学杂志

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.

Research progress on multiscale entropy algorithm and its application in neural signal analysis / 生物医学工程学杂志

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.

Long term power frequency electromagnetic fields exposure influences the causal network connection pattern of local field potentials during working memory / 生物医学工程学杂志

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.

Effect of Baihe Zhimu Tang(百合知母汤)on Airway Inflammation in Bronchial Asthma Rats / 中医杂志

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.