胶原酶对大鼠脊神经背根神经节神经电位传导的影响

目的通过神经电位传导速度测定,研究胶原酶对大鼠脊神经背根神经节功能的影响。方法57只健康的Sprague-Dawley雄性大鼠随机分为正常组、胶原酶急性实验模型组、亚急性实验模型组和慢性实验模型组;急性假手术组、亚急性假手术组和慢性假手术组。分离、暴露实验大鼠左侧腰5背根神经节,并在各胶原酶实验模型组局部滴注胶原酶1ml(1200u/4ml),各假手术组局部滴注生理盐水1ml。分别于注药后1h、1周、30d行包含背根神经节的一段神经的神经电位传导速度检测。统计分析采用统计软件SPSS11.0。结果各组神经电位传导速度相比较差异均无显著性。结论临床应用的胶原酶化学髓核溶解术的胶原酶治疗浓度不影响大鼠脊神经背根神经节和传导神经的神经电生理功能。     

生后早期大鼠初级视皮层Ⅰ层中间神经元电学特性研究

目的:研究视觉发育可塑性关键期内大鼠初级视皮层Ⅰ层中间神经元的电学特性,以期通过分析其电学特性进一步区分神经元的类型。方法:采用脑片膜片钳全细胞记录技术,观察13～15天SD大鼠初级视皮层Ⅰ层单眼反应区(Oc1M)中间神经元的被动、主动电学特性和动作电位的发放特征。结果:大鼠初级视皮层Ⅰ层中间神经元动作电位的后电位表现为后去极化和后超极化两种形式。后去极化的幅度能够达到15.11±3.02 mV;而后超极化的幅度为-6.22±0.53 m V。基于后电位的不同,将Ⅰ层中间神经元分为后去极化神经元(ADPNs)和后超极化神经元(AHPNs)两类。对两类神经元的电学特性进行统计比较发现,ADPNs具有较高的静息电位、较低的阈电位和较高的能障(P<0.05)。此外,两类神经元在动作电位峰幅值、最大下降斜率、峰展宽以及频率适应性上均具有显著性差异(P<0.05)。结论:在视觉发育可塑性关键期内,大鼠初级视皮层Ⅰ层中间神经元可根据其电学特性分为ADPNs和AHPNs两种类型,二者可以进一步通过其被动和主动电学特性以及动作电位发放特性加以区分。     

针极肌电图与神经传导速度检查对腕管综合征患者的诊断价值

目的:提高对腕管综合征(CTS)的诊断水平。方法:应用针极肌电图与神经传导速度(NCV)对30例46侧腕管综合征(CTS)患者进行了检测和分析。结果:正中神经腕管以下支配肌针极肌电图见失神经支配电位而不累及其他神经支配肌;腕管以下正中神经运动传导速度(MCV)、MCV潜伏期及感觉传导速度(SCV)均有不同程度的减慢,MCV潜伏期与针极肌电图的异常率比值极其相近,之间存在显著相关性。不经过腕管的尺神经与腕管以上的正中神经传导速度(NCV)均正常。结论:针极肌电图对观察CTS的损害范围与程度有重要意义,NCV不同部位和分节段的检查可以排除其他周围神经病变而确诊CTS。     

情绪词语对摔跤运动员心理表象影响的事件相关电位研究

目的:探讨情绪词语对摔跤运动员心理表象任务影响的行为特征及事件相关电位特点。方法:研究对象为24名二级以上摔跤运动员,从汉语情感词系统中选取积极词语和消极词语各40个作为情绪启动材料,心理旋转任务为旋转的字母R。脑电记录采用事件相关电位技术(ERPs)。结果:(1)随着字母R旋转角度的增加,反应时逐渐增大(P<0.01),正确率逐渐减小(P<0.01);(2)Cz电极的P300峰潜伏期显著小于其他三个电极位置(P<0.01),Pz与Cz的P300峰波幅分别显著大于P4与P3处(P<0.05);(3)积极词语诱导条件的P300峰潜伏期显著短于消极词语诱导条件(P<0.05)。结论:(1)摔跤运动员在两种情绪条件下:随着旋转角度的增加,反应时逐渐增加而正确率逐渐下降;在心理表象过程中,脑部顶叶靠近枕区的激活速度与加工速度慢于中央区,且脑中央区位置付出了较多的认知负荷。(2)积极情绪词语有助于提高摔跤运动员在心理表象过程中的空间认知加工与转换速度,提示在平时训练过程中教练员应多使用积极性词语进行暗示,以提高运动员的运动竞技表现。     

突触前状态对梭曼阻断神经节作用的影响 Ⅲ.突触前状态与梭曼引起豚鼠上颈交感神经节细胞电位变化的关系

用微电极记录豚鼠上颈交感神经节细胞膜电位及刺激节前神经干诱发的动作电位。在刺激节前神经干状态下,梭曼使细胞膜电位逐渐升高,诱发的动作电位幅度逐渐减少,15min后节细胞膜电位持续在一较高水平,刺激节前神经不再诱发动作电位,梭曼引起节细胞的这些变化未见有自动恢复的趋向。另外,在不刺激节前神经条件下,梭曼对节细胞的膜电位和刺激节前神经诱发的动作电位无影响。提示突触前状态在梭曼阻断神经节中有重要作用。     

甲亢突眼征眼部动脉血流频谱特征和血流动力学研究

目的:探讨甲亢突眼征眼部动脉血流频谱特征和血流参数变化的规律,及与眼轴、眼压等的关系。方法:应用彩色多普勒超声诊断仪对甲亢突眼征患者(31例,62只眼)和正常人(25例,50只眼)的眼动脉(OA)、睫状后短动脉(SPCA)、视网膜中央动脉(CRA)的收缩期峰值流速(PSV)、舒张期最小流速(EDV)和阻力指数(RI)以及眼轴等进行检测。结果:①6项超声指标中,甲亢突眼组与正常对照组比较,眼轴、球横径无显著性差异(P>0.05);球尖距、球后软组织周长、球后软组织面积及球后软组织体积差异显著(P<0.05或<0.01)。②甲亢突眼征眼部动脉频谱形态OA第一峰高尖,第二峰降低圆钝,甚至出现两峰融合,峰时延长、后移;SPCA第一峰增高且宽大,第二、三波峰圆钝,峰时后移;CRA第一峰上升速度明显加快,波峰较高,而第二峰峰时延长、后移。③眼部血流动力学变化特点为:甲亢突眼组与正常对照组比较OA、SPCA和CRA的PSV均明显增高(P<0.01),EDV和RI有显著性差异(P<0.05,P<0.01)。结论:甲亢突眼征眼部血流频谱形态特征、血流动力学参数和球尖距、球后软组织周长、球后软组织面积及球后软组织体积发生改变。     

儿童胚胎发育不良性神经上皮瘤的影像表现分析

目的 :分析胚胎发育不良性神经上皮瘤(DNT)的CT及MRI特征,提高对该病的影像学认识。方法 :收集13例经病理证实的DNT的临床资料,回顾性分析其影像学特点。结果:13例均以抽搐或癫痫就诊,病灶均位于大脑半球。CT表现为低密度,边界清晰,无瘤周水肿及占位效应。MRI信号特征为T1WI呈低信号,T2WI呈高信号,T2FLAIR呈稍低信号,周围有稍高信号环,DWI呈稍低信号;增强扫描病灶无强化8例,轻度或线状强化5例;"环形征"7例,"倒三角征"6例;5例行MRS分析,表现为NAA峰降低,CHO峰升高。结论 :DNT的MRI特点具有一定特征性,结合CT及临床表现对DNT的诊断及鉴别诊断有重要价值。     

椎管内神经源性肿瘤的MRI分析

目的:提高MRI对椎管内神经源性肿瘤定性和定位诊断的准确率。材料与方法:神经源性肿瘤27例(男13例,女14例;年龄7-68岁),经病理证实其中神经鞘瘤18例,神经纤维瘤9例,所有病例最初均经采用快速SE T_1加权和T_2加权序列行MR成像,其中5例还附加作了增强扫描。结果:神经鞘瘤和神经纤维瘤在T_1加权像上未见特征性表现,但在T_2加权像上多数表现为有短T_2低信号的包膜内有长T_2信号或混杂信号,长T_2信号强度与脑脊液者相似。同时,还通过MRI找出了椎管内神经源性肿瘤的分布、位置、形态特征等。结论:神经鞘瘤和神经纤维瘤都有赖以增强的MRI可证实的恒定的增强与形态特征,因此MRI,尤其是增强的MRI可用于判定神经源性肿瘤的性质与位置。     

椎管内脊膜瘤及神经源性肿瘤MRI增强影像的特征性分析

目的:分析椎管内脊膜瘤及神经源性肿瘤MR增强影像的特征。方法:搜集经手术病理证实的椎管内脊膜瘤11 例,神经源性肿瘤12例,全部病例均行MR平扫及增强扫描。结果:椎管内脊膜瘤MR增强影像特征为“肿瘤周边重度环状增强”、脊膜“尾巴征”;神经鞘瘤MR增强影像特征为多灶样不增强;神经纤维瘤MR增强影像特征为病灶内星芒状不增强。结论:椎管内脊膜瘤及神经源性肿瘤都有各自的MR增强影像特征,其对定性诊断有重要价值     

强短声诱发的清醒豚鼠咬肌肌源性电位

目的建立强短声诱发的咬肌肌源性电位的豚鼠模型,并确定该电位的起源。方法17只豚鼠随机分成3组,正常对照组5只;5只豚鼠以450 mg/kg剂量每天肌注阿米卡星1次,持续注射18 d,以选择性药物破坏耳蜗;5只豚鼠左侧圆窗区滴注庆大霉素0．05 ml(40 mg/ml)以选择性破坏前庭,另有2只豚鼠左侧圆窗区滴注生理盐水0．05 ml以作为听泡开窗的对照。3组动物分别进行冷热实验、强短声诱发的咬肌肌源性电位以及听性脑干反应(ABR)测试。结果正常对照组豚鼠,120、110、100和90 dB单耳声刺激,单侧记录到的豚鼠咬肌肌源性电位的反应率分别为100%、90%、70%和0%。120、110和100 dB声刺激诱发的肌源性电位的正负波的潜伏期分别为6．73±0．59 ms和8．84±0．56 ms,6．80±0．43 ms和8．92±0．48 ms,以及6．94±0．49 ms和9．00±0．51 ms。平均峰间幅度分别为6．23±2．37μV、6．12±2．24μV和6．36±3．13μV,刺激强度对豚鼠的咬肌肌源性电位的平均潜伏期或峰间幅度无显著影响。采用庆大霉素单侧处理的豚鼠,损伤侧的冷热反应均缺失,而ABR阈值却正常,其损伤同侧声刺激诱发的咬肌肌源性电位缺失。阿米卡星处理组豚鼠冷热实验正常,双侧ABR阈值显著增加,但短声诱发的咬肌肌源性电位均存在。结论豚鼠强短声诱发的咬肌肌源性电位来源于前庭而非耳蜗。     

Fast human brain magnetic resonance responses associated with epileptiform spikes

Neuronal currents produce local electromagnetic fields that can potentially modulate the phase of the magnetic resonance signal and thus provide a contrast mechanism tightly linked to neuronal activity. Previous work has demonstrated the feasibility of direct MRI of neuronal activity in phantoms and cell culture, but in vivo efforts have yielded inconclusive, conflicting results. The likelihood of detecting and validating such signals can be increased with (i) fast gradient‐echo echo‐planar imaging, with acquisition rates sufficient to resolve neuronal activity, (ii) subjects with epilepsy, who frequently experience stereotypical electromagnetic discharges between seizures, expressed as brief, localized, high‐amplitude spikes (interictal discharges), and (iii) concurrent electroencephalography. This work demonstrates that both MR magnitude and phase show large‐amplitude changes concurrent with electroencephalography spikes. We found a temporal derivative relationship between MR phase and scalp electroencephalography, suggesting that the MR phase changes may be tightly linked to local cerebral activity. We refer to this manner of MR acquisition, designed explicitly to track the electroencephalography, as encephalographic MRI (eMRI). Potential extension of this technique into a general purpose functional neuroimaging tool requires further study of the MR signal changes accompanying lower amplitude neuronal activity than those discussed here. Magn Reson Med, 2010. © 2010 Wiley‐Liss, Inc.     

利用小波级数检测癫痫EEG中的棘波

目的 研究自动提取癫痫脑电中棘波。方法 把ＥＥＧ信号分解成小波级数，在各个尺度上，利用信号细节在两个过零点之间的平均振幅确定瞬态波形的大小，通过选择平均振幅中的局部极值检测刺波。结果 对６位患者的ＥＥＧ信号进行处理，检测刺波的正确率为９６．６６％，结论 这种方法能够比较准确地检测ＥＥＧ中的棘波。     

Combining EEG and fMRI: a multimodal tool for epilepsy research

Patients with epilepsy often present in their electroencephalogram (EEG) short electrical potentials (spikes or spike-wave bursts) that are not accompanied by clinical manifestations but are of important diagnostic significance. They result from a population of abnormally hyperactive and hypersynchronous neurons. It is not easy to determine the location of the cerebral generators and the other brain regions that may be involved as a result of this abnormal activity. The possibility to combine EEG recording with functional MRI (fMRI) scanning opens the opportunity to uncover the regions of the brain showing changes in the fMRI signal in response to epileptic spikes seen in the EEG. These regions are presumably involved in the abnormal neuronal activity at the origin of epileptic discharges. This paper reviews the methodology involved in performing such studies, particularly the challenge of recording a good quality EEG inside the MR scanner while scanning is taking place, and the methods required for the statistical analysis of the combined EEG and fMRI time series. We review the results obtained in patients with different types of epileptic disorders and discuss the difficult theoretical problems raised by the interpretation of an increase (activation) and decrease (deactivation) in blood oxygen level dependent (BOLD) signal, both frequently seen in response to spikes.     

混沌动力学在心率变异分析中的应用

目的 利用混沌动力学方法进行心率变异信号的非线性特征描述和检测.方法 根据Takens延迟方法进行心率变异信号的状态空间重构,结合奇异值分解技术给出规律的吸引子形态,并通过相关积分计算相应的信号关联维值.结果 以实例形式给出健康人心率变异信号的典型吸引子和相应关联维计算结果.结论 混沌动力学在心率变异信号处理中的应用有望为某些心脏疾病的辅助临床诊断和治疗提供一个新的途径。     

培养神经元网络对不同间隔电脉冲刺激的响应

目的分析培养神经元网络对不同时间间隔电脉冲刺激动作电位发放的影响。方法对培养在多电极阵列（multielectrode arrays，MEA）芯片上的大鼠海马神经元网络加入不同时间间隔的2次电脉冲。结果随刺激间隔时间减小，第2次响应持续时间增加。典型的是，10ms间隔的刺激，第2次响应持续时间有很大增加，并且出现快响应（10ms内）和慢响应（接近或超过100ms）2个阶段。而100ms间隔的刺激，两次响应之间没有明显联系，延时短，锋电位幅值低，个数少，与采用独立单个脉冲刺激实验结果类似。结论培养神经元网络发放受不同电刺激模式的影响。与自发发放比较，不同刺激分别使网络的活动明显得到增强或受到抑制。     

Magnetic resonance imaging of neuronal and glial swelling as an indicator of function in cerebral tissue slices.

Here we demonstrate a new basis of signal change in magnetic resonance imaging (MRI) related to neuronal function, independent of blood oxygenation or flow. Time series MRI data acquired from living, superfused brain slices of adult rats revealed that the signal intensity reversibly increased with depolarization evoked by briefly elevating extracellular K(+). This was presumably a consequence of increased tissue water in the intracellular compartment. Reversible increases in light transmittance (LT) demonstrating a similar time course in response to K(+) elevation supported cellular swelling as generating the MRI signal intensity changes. This was confirmed by reversibly swelling cells in the slice under hypoosmotic challenge, which increased both MRI and LT signals with an identical time course. Conversely, shrinking cells under hyperosmotic challenge reversibly decreased the MRI and LT signals. We propose that specific MRI of neuronal function (fMRI) signals detected under identical parameters during predominantly proton-density-weighted fMRI of the spinal cord can now be explained by neuronal and glial swelling in activated central nervous system (CNS) regions. These observations demonstrate the biophysical basis of the fMRI contrast mechanism that has been termed "signal enhancement by extravascular water protons," or SEEP.     

The principles of quantification applied to in vivo proton MR spectroscopy

Following the identification of metabolite signals in the in vivo MR spectrum, quantification is the procedure to estimate numerical values of their concentrations. The two essential steps are discussed in detail: analysis by fitting a model of prior knowledge, that is, the decomposition of the spectrum into the signals of singular metabolites; then, normalization of these signals to yield concentration estimates. Special attention is given to using the in vivo water signal as internal reference.     

基于灰色关联度k-近邻法的房性心律失常识别

目的 研究用灰色理论的灰色关联度结合k-近邻法快速准确地识别窦性、房扑和房颤信号.方法 将心电信号分成训练集和测试集,首先用多尺度小波将心电信号变换到时频域,然后提取小波系数矩阵的奇异值作为信号的特征向量,将所有训练样本的特征向量作为标准模板,求出测试样本特征向量与标准模板之间的灰关联系数,最后结合k-近邻法对测试样本做出判断.分别用MIT-BIH心律失常数据库和犬心外膜信号数据库来评价提出的基于灰关联度的k-近邻法识别心律失常信号的特异性、敏感性和准确率.结果 实验结果表明:和常规灰关联度法、常规k-近邻法、BP神经网络相比,本方法对窦性、房扑和房颤信号有较好的识别性能,且具有识别速度快的优点.结论 本方法不需要大量的训练样本,计算简单,能较准确快速地识别窦性、房扑和房颤信号,有望应用于治疗心律失常的可植入装置.     

Nitric oxide amplifies the excitatory to inhibitory neurotransmitter imbalance accelerating oxygen seizures.

CNS O2 toxicity is manifested most profoundly by generalized motor convulsions. The hypothesis was tested that HBO2 triggers seizures by an excitatory to inhibitory neurotransmitter imbalance produced by neuronal nitric oxide (NO) activity. Anesthetized rats were exposed to 5 ATA HBO2 for 75 min with or without prior inhibition of nNOS. Interstitial NO and amino acids: aspartate (Asp), glutamate (Glu) and gamma-aminobutyric acid (GABA) were determined in the striatum by microdialysis coupled with HPLC. Blood flow and EEG in the same striatal region were measured simultaneously. Rats treated with 7-NI showed no EEG spikes of O2 toxicity, while seizure latency for untreated rats was 63 +/- 7 min. Significant increases in NO metabolites and blood flow were observed in control rats before seizures. HBO2 did not change Glu significantly and increased Asp slightly whereas GABA decreased progressively by 37 +/- 7%. Pretreatment with 7-NI led to a significantly smaller decline in GABA. Overall, the simplified excitotoxicity index Glu/GABA increased significantly after 60 min of HBO2 in control but fell in rats treated with 7-NI. We conclude that HBO2-stimulated neuronal NO production promotes an imbalance between glutamatergic and GABAergic synaptic function implicated in the genesis of oxygen-induced seizures.     

Proton MR spectroscopic imaging without water suppression

To improve reproducibility in proton magnetic resonance (MR) spectroscopic imaging in human brain, simultaneous acquisition of the internal water reference and metabolite signals was evaluated. Measurements in healthy volunteers showed that the increase in dynamic range from signal oversampling was sufficient to avoid digitization errors. In addition, use of singular value decomposition techniques and finite impulse response filters proved effective in separating water and metabolite signals and providing estimates of the metabolite concentrations.