Single-trial decoding of imagined grip force parameters involving the right or left hand based on movement-related cortical potentials

Time–domain feature representation for imagined grip force movement-related cortical potentials(MRCP)of the right or left hand and the decoding of imagined grip force parameters based on electroencephalogram(EEG)activity recorded during a single trial were here investigated.EEG signals were acquired from eleven healthy subjects during four different imagined tasks performed with the right or left hand.Subjects were instructed to execute imagined grip movement at two different levels of force.Each task was executed 60 times in random order.The imagined grip force MRCP of the right or left hand was analyzed by superposition and averaging technology,a single-trial extraction method,analysis of variance(ANOVA),and multiple comparisons.Significantly different features were observed among different imagined grip force tasks.These differences were used to decode imagined grip force parameters using Fisher linear discrimination analysis based on kernel function(k-FLDA)and support vector machine(SVM).Under the proposed experimental paradigm,the study showed that MRCP may characterize the dynamic processing that takes place in the brain during the planning,execution,and precision of a given imagined grip force task.This means that features related to MRCP can be used to decode imagined grip force parameters based on EEG.ANOVA and multiple comparisons of time–domain features for MRCP showed that movement-monitoring potentials(MMP)and specific interval(0–150 ms)average potentials to be significantly different among 4 different imagined grip force tasks.The minimum peak negativity differed significantly between high and low amplitude grip force.Identification of the 4different imagined grip force tasks based on MMP was performed using k-FLDA and SVM,and the average misclassification rates of 27%±5%and 24%±4%across 11 subjects were achieved respectively.The minimum misclassification rate was 15%,and the average minimum misclassification rate across 11 subjects was24%±4.5%.This investigation indicates that imagined grip force MRCP may encode imagined grip force parameters.Single-trial decoding of imagined grip force parameters based on MRCP may be feasible.The study may provide some additional and fine control instructions for brain–computer interfaces.     

动态脑电图联合脑干听觉诱发电位在脑卒中患者预后评估中的应用价值

目的探讨动态脑电图联合脑干听觉诱发电位在脑卒中患者预后评估中的应用价值.方法选取脑卒中患者152例,随机分为观察组和对照组,每组各76例.观察组患者选用动态脑电图结合脑干听觉诱发电位进行监测,对照组患者选用常规脑电图进行监测,对比两组患者预后评估结果和预后评估中价值.结果观察组患者中真阴性和真阳性的例数均明显多于对照组,差异具有统计学意义(P0.05);观察组患者中假阴性和假阳性的人数均明显少于对照组,差异具有统计学意义(P0.05).观察组患者检测的敏感性、特异性、错误率均明显高于对照组,准确率明显低于对照组,差异具有统计学意义(P0.05).结论动态脑电图联合脑干听觉诱发电位能够有效增加脑卒中患者预后评估的特异性和敏感性,提高评估的准确率,值得在临床治疗中推广使用.     

顿悟脑的10年:人类顿悟脑机制研究进展

自21世纪首次借助脑成像技术对解决字谜任务过程中顿悟一瞬间的大脑活动状况进行研究以来,目前已有近10年的历史,获得了许多富有价值的研究.这些研究从顿悟的时间进程和脑神经基础两方面对顿悟的大脑机制进行了丰富的探讨,并形成了有关人类解决顿悟问题的"顿悟脑"的神经框架.研究显示,顿悟脑主要由外侧前额叶、扣带回、海马、颞上回、梭状回、楔前叶、楔叶、脑岛和小脑组成.就各脑区的功能而言,外侧前额叶主要负责顿悟难题思维定势的转移和打破,扣带回则参与新旧思路的认知冲突以及解题进程的监管,海马、颞上回和梭状回组成了"三维一体"的、专门负责新异而有效联系形成的神经网络,问题表征的有效转换则依赖于楔叶和楔前叶组成的"非言语的"视觉空间信息加工网络,脑岛负责认知灵活性和顿悟相关情绪体验,反应相关手指运动的皮下控制则依赖于小脑.     

一次性“健身气功·六字诀”锻炼对事件相关电位P300的影响

目的：探讨健身气功六字诀对事件相关电位P300的影响,为六字诀锻炼对认知功能影响的评价提供实验支持。方法：采用上海海神医疗电子仪器厂生产的NDI-200（海神号）神经电检诊仪记录并分析了18名女性受试者分别进行健身气功六字诀和瑜伽完全呼吸锻炼前及锻炼后即刻Pz点的视觉诱发事件相关电位及反应时。结果：与锻炼前相比,锻炼后即刻P300潜伏期显著性缩短（P〈0．05）,而波幅和反应时都无显著性差异。结论：健身气功六字诀对认知功能具有正向影响效应,表现为P300潜伏期显著缩短。     

CR传输线解析EIS确定Bi/Bi_2O_3体系平带电位

电化学阻抗谱是表征金属/氧化物体系的强大工具,应用关键是正确解析.许多金属氧化物有半导体特征,平带电位是关键参数,以文献Bi/Bi2O3体系EIS实例说明根据CR传输线离散参数Ci随特征频率fi的分布,能从共存的多个表面态电容CSS中鉴别出空间电荷层电容CSC,直接根据Mott-Schottky关系得到较准确的平带电位,最后讨论了方法的合理性.     

基态原子价电子平均能的估算及应用

本文提出了一个判断元素化学分性的能量标度，它对周期表中元素性质的递变给予了较为合理的解释，用值划分的化合的价键类型与实验数据相一致。     

电离势,电子亲和势,电负性与酸碱软硬度

本文用Lewis酸的平均电离势对其电负性作图;用Lewis碱的第一电子亲和势对其电负性作图,得出分类软酸、硬酸和软碱、硬碱的两个方程: H_A=∑I_n/n-3.1x 2.6 (1) H_B=A 3.51x-7.24 (2)运用(1)式计算了113种酸的硬度值,用(2)式计算了59种碱的硬度值。突破了复杂酸碱的标度问题。结果与Dearson根据实验所总结的分类一致,与Ahrland和Klopman结果相比较大致呈线性关系。     

关于一类非多项式位势的Littlewood问题(英文)

本文证明了方程+x²ⁿ⁺¹+P_x（x,t）=0所有解的有界性,其中n≥1,P（x,t）是关于两个变量x与t都是光滑的1-周期函数.     

带双势的非线性Klein-Gordon方程驻波的不稳定性

研究了一类带双势的非线性Klein Gordon方程的柯西问题.首先利用变分法得出了具基态的驻波的存在性,然后根据这个结果证明了该驻波的不稳定性.