视觉P300脑机接口中的SOA扰动现象

异步操控性是脑机接口走向实际应用的关键技术之一.其关键点在于寻找一种可有效区分脑机接口工作状态和空闲状态的指标.建立了针对P300脑机接口的刺激起始异步(SOA)扰动模型,在仿真实验和实测数据中观察到SOA扰动谱线,并根据所提出的模型给出了合理解释.研究了SOA扰动的频域特性,结果表明,当SOA位于220 ms附近时,SOA扰动的强度最大,而当SOA低于150 ms时,SOA扰动强度将急剧减小.同时SOA扰动所具有的锁相性使得可以通过时域相干平均法进一步提高信噪比.SOA扰动可作为脑机接口处于工作状态的标志,为异步脑机接口的实现提供了一种新的研究思路.     

监护记录信号数据的处理与显示方法

在工程及医学领域中,需监测许多参数,如重要设备的振动、温度、血压、转速、大电机电流等。如果观察时间较长,就会得到海量数据,从而需要花费大量时间分析信号。本文描述了一种用来帮助分析信号的彩图技术,论述了处理彩图的原理和步骤。该技术已经在睡眠研究中得到验证,并且开发出一个名为睡眠观测的彩图工具,其中包含几种不同类型的彩图。因为人对有区别的图像非常敏感,所以睡眠阶段可以很容易地从图中分辨出来。对于用二维     

Polarized light imaging of white matter architecture

Polarized light imaging (PLI) is a method to image fiber orientation in gross histological brain sections based on the birefringent properties of the myelin sheaths. The method uses the transmission of polarized light to quantitatively estimate the fiber orientation and inclination angles at every point of the imaged section. Multiple sections can be assembled into a 3D volume, from which the 3D extent of fiber tracts can be extracted. This article describes the physical principles of PLI and describes two major applications of the method: the imaging of white matter orientation of the rat brain and the generation of fiber orientation maps of the human brain in white and gray matter. The strengths and weaknesses of the method are set out.     

Subacute proteome changes following traumatic injury of the developing brain: Implications for a dysregulation of neuronal migration and neurite arborization

Traumatic brain injury (TBI) is a major cause of morbidity and mortality among children and adolescents. To gain insight into developmental events influenced by TBI, we analyzed subacute mouse brain proteome changes in a percussion head trauma model at P7 ipsi- and contralateral to the site of injury. The comparison of brain proteomes of trauma mice and controls revealed reproducible changes in the intensity of 28 proteins (30 protein spots) in response to trauma. The changes detected suggest that TBI leads to apoptosis, inflammation, and oxidative stress. These changes were consistent with our results of histological and biochemical evaluation of the brains which revealed widespread apoptotic neurodegeneration, microglia activation, and increased levels of protein carbonyls. Furthermore, we detected changes in proteins involved in neuronal migration as well as axonal and dendritic growth and guidance, suggesting interference of trauma with these developmental events.     

适用于高炉冲渣水池中的泄水孔设置

通过马钢股份公司一铁总厂高炉冲渣循环水设施冲渣水池的设计,按照地下存在,水池需满足抗浮要求,计算出水池底板和配筋;以及在水池中设置泄水孔,不考虑水池抗浮,从而选取合理方案,达到节约大量工程资金的目的。     

用MindManager辅助教学的设想

鉴于Powerpoint翻页式内容呈现方式缺乏对人的思维过程的有效模拟,需要必要的教学内容呈现补充手段,提出一种基于全脑图的教学内容呈现思路——基于MindManager的辅助教学模式,并给出了具体的教学课件设计实例.利用MindManager软件开发工具,设计全脑图模拟人的思维过程,突破了传统教学手段模式的限制,有效提高了教学内容的表现力,对教学实践具有一定的指导意义.     

张量线性判别分析算法的脑灰质MRI结像分析

大脑结构MRI数据本质上是三维张量数据,而传统机器学习方法在提取大脑结构特性信息时,需要将其展开为一维向量,破坏了数据的内在结构信息.为了克服数据向量化带来的缺点,提出使用张量线性判别分析算法,用于大脑结构MRI数据分析.并对比基于向量的主成分线性判别分析算法,对20个正常人和20个精神病患者的脑灰质MRI结像进行分类.结果表明张量线性判别分析算法的最高识别率达到95%,其总体识别率、鲁棒性都要优于主成分线性判别分析算法.张量线性判别分析算法在大脑MRI数据分类上要优于传统基于向量的机器学习方法.     

Texture analysis of poly-adenylated mRNA staining following global brain ischemia and reperfusion

Texture analysis provides a means to quantify complex changes in microscope images. We previously showed that cytoplasmic poly-adenylated mRNAs form mRNA granules in post-ischemic neurons and that these granules correlated with protein synthesis inhibition and hence cell death. Here we utilized the texture analysis software MaZda to quantify mRNA granules in photomicrographs of the pyramidal cell layer of rat hippocampal region CA3 around 1 h of reperfusion after 10 min of normothermic global cerebral ischemia. At 1 h reperfusion, we observed variations in the texture of mRNA granules amongst samples that were readily quantified by texture analysis. Individual sample variation was consistent with the interpretation that animal-to-animal variations in mRNA granules reflected the time-course of mRNA granule formation. We also used texture analysis to quantify the effect of cycloheximide, given either before or after brain ischemia, on mRNA granules. If administered before ischemia, cycloheximide inhibited mRNA granule formation, but if administered after ischemia did not prevent mRNA granulation, indicating mRNA granule formation is dependent on dissociation of polysomes. We conclude that texture analysis is an effective means for quantifying the complex morphological changes induced in neurons by brain ischemia and reperfusion.     

Prospective issues for error detection

From the literature on error detection, the authors select several concepts relating error detection mechanisms and prospective memory features. They emphasize the central role of intention in the classification of the errors into slips/lapses/mistakes, in the error handling process and in the usual distinction between action-based and outcome-based detection. Intention is again a core concept in their investigation of prospective memory theory, where they point out the contribution of intention retrievals, intention persistence and output monitoring in the individual's possibilities for detecting their errors. The involvement of the frontal lobes in prospective memory and in error detection is also analysed. From the chronology of a prospective memory task, the authors finally suggest a model for error detection also accounting for neural mechanisms highlighted by studies on error-related brain activity.