Negative BOLD Response to Interictal Epileptic Discharges in Focal Epilepsy

In EEG–fMRI studies, BOLD responses related to interictal epileptic discharges (IEDs) are most often the expected positive response (activation) but sometimes a surprising negative response (deactivation). The significance of deactivation in the region of IED generation is uncertain. The aim of this study was to determine if BOLD deactivation was caused by specific IED characteristics. Among focal epilepsy patients who underwent 3T EEG–fMRI from 2006 to 2011, those with negative BOLD having a maximum t-value in the IED generating region were selected. As controls, subjects with maximum activation in the IED generating region were selected. We established the relationship between the type of response (activation/deactivation) and (1) presence of slow wave in the IEDs, (2) lobe of epileptic focus, (3) occurrence as isolated events or bursts, (4) spatial extent of the EEG discharge. Fifteen patients with deactivation and 15 with activation were included. The IEDs were accompanied by a slow wave in 87 % of patients whose primary BOLD was a deactivation and only in 33 % of patients with activation. In the deactivation group, the epileptic focus was more frequently in the posterior quadrant and involved larger cortical areas, whereas in the activation group it was more frequently temporal. IEDs were more frequently of long duration in the deactivation group. The main factor responsible for focal deactivations is the presence of a slow wave, which is the likely electrographic correlate of prolonged inhibition. This adds a link to the relationship between electrophysiological and BOLD activities.     

脑不同部位损害与失写症

语言是以语音或字形为物质外壳 ,以词汇为建筑材料 ,以语法为结构规律而构成的体系。它是人类特有的复杂的认知心理活动 ,是通过应用符号交流的能力 ,包括口头和书面两种主要形式。作为一种主要的书面交流途径 ,书写是语言计划借助于笔和纸实现的手势过程[1] ,它有赖于听觉、视觉、运动觉、视空间功能和运动功能的完整性。脑不同部位损害在引起神经躯体体征的同时 ,还有可能引起口头语言障碍 (失语 )或书面文字感知障碍 (失读 ) ,也常会伴随或单独损害书写功能。早在 1867年Ｏｇｌｅ就提出失写症一词。虽然历史上对语言障碍曾有机能整体学说…     

癫痫大鼠弓状核神经元损伤性改变—光、电镜定量研究

本文采用光、电镜定量方法观察了马桑内酯所致急性局灶型癫痫大鼠弓状核神经元损伤性改变。结果显示 ,对照组和癫痫组大鼠弓状核神经元胞体的面积分数、面数密度和神经元胞体、胞核等效直径无显著差异 ( P>0 .0 5 ) ;癫痫组弓状核亮细胞未见明显改变 ( P>0 .0 5 ) ,而暗细胞内线粒体体积分数减少 ( P<0 .0 5 ) ,粗面内质网的体积分数增加 ( P<0 .0 5 ) ,两者的面数密度无显著性变化 ( P>0 .0 5 ) ,溶酶体的体积分数及面数密度均增加 ( P<0 .0 5 )。以上结果提示 ,癫痫大鼠弓状核神经元超微结构的改变 ,亮、暗细胞反应不同 ;癫痫所致神经内分泌功能紊乱 ,可能与弓状核神经元损伤有关     

Association Between the Basal Ganglia and Large-Scale Brain Networks in Epilepsy

Epilepsy may affect connectivity between the putamen and cortex even during the resting state. Putamen is part of the basal ganglia resting state network (BG-RSN) which is anti-correlated with the default mode network (DMN) in healthy subjects. Therefore, we aimed at studying the functional brain connectivity (FC) of the putamen with the cortical areas engaged in the DMN as well as with the primary somatomotor cortex which is a cortical region engaged in the BG-RSN. We compared the data obtained in patients with epilepsy with that in healthy controls (HC). Functional magnetic resonance imaging (fMRI) was performed in 10 HC and 24 patients with epilepsy: 14 patients with extratemporal epilepsy (PE) and 10 patients with temporal epilepsy (PT). Resting state fMRI data was obtained using the 1.5 T Siemens Symphony scanner. The Group ICA of fMRI Toolbox (GIFT) program was used for independent component analysis. The component representing the DMN was chosen according to a spatial correlation with a mask typical for DMN. The FC between the putamen and the primary somatomotor cortex was studied to assess the connectivity of the putamen within the BG-RSN. A second-level analysis was calculated to evaluate differences among the groups using SPM software. In patients with epilepsy as compared to HC, the magnitude of anti-correlation between the putamen and brain regions engaged in the DMN was significantly lower. In fact, the correlation changed the connectivity direction from negative in HC to positive in PE and PT. The disturbed FC of the BG in patients with epilepsy as compared with HC was further illustrated by a significant decrease in connectivity between the left/right putamen and the left/right somatomotor cortex, i.e. between regions that are engaged in the BG-RSN. The FC between the putamen and the cortex is disturbed in patients with epilepsy. This may reflect an altered function of the BG in epilepsy.     

Topographic Disorientation in Patients with Brain Damage

Neuroscience and Behavioral Physiology - This article describes the symptoms, pathogenesis, and variants of topographic disorientation. Methods for the diagnosis and rehabilitation of patients are...     

青少年肌阵挛癫痫患者的大尺度脑网络研究

采用静息态功能性磁共振成像(rs-fMRI)数据探究青少年肌阵挛癫痫(JME)患者大尺度脑网络的变化。采集17例JME患者和15名正常志愿者的脑部静息态功能磁共振成像数据,两组均使用偏相关系数构建静息态脑网络。分别计算JME患者组与正常对照组的阈值,构建二值化脑网络。计算两组被试各个脑区的介数值,采用双样本t检验对比两组脑网络介数值的差异(Bonferroni 校正,P<0.01),找出介数值发生显著变化脑区。结果表明,偏相关系数构造的脑网络具有小世界属性。JME患者组脑网络中脑区的介数值相比正常对照组有显著性差异。与正常对照组相比,JME患者组介数值显著降低的脑区有2个,介数值显著升高的脑区有17个。其中属于默认模式网络(DMN)的脑区有8个,属于突显网络(SN)的脑区有5个。JME患者组介数值显著降低的脑区有右侧中央旁小叶和右侧后扣带回,介数值显著增高脑区主要是右侧背外侧额上回、左侧枕中回、右侧楔前叶和右侧舌回等。JME患者介数值发生显著改变的脑区主要属于默认模式网络和突显网络。可以推断出默认模式网络和突显网络内部脑区间连接发生改变,信息传递产生变化。由此可能会导致JME患者大脑功能发生改变,造成患者的认知能力与执行能力等功能受损。     

Patterns of Functional Connectivity in the Brain in Temporal and Frontal Epilepsy

Neuroscience and Behavioral Physiology - Objectives. To identify the pattern of functional connectivity (FC) between areas and networks in the brain in patients with frontal and temporal foci of...     

基于自适应多尺度脑功能连接的局灶性癫痫发作检测方法研究

利用长时程脑电图检测癫痫发作是临床中较为广泛的应用,然而这项工作乏味、耗时,且很大程度上依赖于临床医生的自身经验和主观判断,准确性和可重复性也较低。针对长时程脑电图检测癫痫中存在的问题,提出一种基于自适应多尺度脑功能连接的癫痫发作检测方法(AMBFC),并选取10例局灶性癫痫患者的发作期和非发作期的样本作为研究对象。首先在一个滑动时间窗内,通过多元经验模态分解(MEMD)提取19通道脑电信号的7个本征模函数(IMF)分量及残差;然后建立多变量自回归(MVAR)模型,利用有向传递函数(DTF)提取流出信息强度,进行特征组合,并通过主成分分析(PCA)降维保留原始特征数目的85%;最后经代价敏感支持向量机(CSVM)分类区分发作期和非发作期脑电,并通过五重交叉验证进行癫痫发作检测算法的效果评价。结果表明,AMBFC算法检测脑电癫痫发作得到的平均准确率为98.6%,精确率为81.9%,召回率为81.4%,F2值为0.80。与各IMF分量、DTF-CSVM算法等检测结果相比,AMBFC算法更具有优越性。有望应用于长时程脑电的实时监测。     

Cerebral Carbohydrate and Energy Metabolism in Perinatal Hypoxic-Ischemic Brain Damage

Cerebral hypoxia-ischemia remains a major cause of acute perinatal brain injury. Research in experimental animals over the past decade has greatly expanded our knowledge of those oxidative events which occur during a hypoxic-ischemic insult to the brain, as well as those metabolic alterations which evolve during the recovery period following resuscitation. The available evidence suggests that hypoxia alone does not lead to brain damage, but rather a combination of hypoxia-ischemia or isolated cerebral ischemia is a necessary prerequisite for tissue injury to occur. Furthermore, hypoxia-ischemia severe enough to produce irreversible tissue injury is always associated with major perturbations in the energy status of the perinatal brain which persists well into the recovery period. The lingering energy depletion sets in motion a cascade of biochemical alterations that are initiated during the course of the insult and proceed well into the recovery period to culminate in either neuronal necrosis or infarction. Unlike the adult, where glucose supplementation prior to or during hypoxia-ischemia accentuates tissue injury, glucose treatment of perinatal animals subjected to a similar insult substantially reduces the extent of tissue injury. The mechanism for the age-specific effect of glucose on hypoxic-ischemic brain damage is discussed in relation to pathogenetic mechanisms responsible for the occurrence of permanent brain damage.     

Resistance to Neurodegenerative Brain Damage in August and Wistar Rats

In Wistar and August rats characterized by different resistance to acute emotional stress we compared the resistance to neurodegenerative brain damage (model of Alzheimer’s disease) produced by administration of a neurotoxic peptide fragment (25–35) β-amyloid into the brain. August rats were more resistant to acute stress and development of neurodegenerative disorders compared to Wistar rats. This conclusion was derived from studying animal behavior in conditioned passive avoidance task and open-field test that characterize cognitive function of the brain. Administration of β-amyloid modulated the behavior of Wistar rats, which reflected the impairment of memory and orientation and exploratory activity in these animals. These disturbances in Wistar rats were accompanied by activation of lipid peroxidation in the hippocampus.__________Translated from Byulleten’ Eksperimental’noi Biologii i Meditsiny, Vol. 139, No. 5, pp. 491–494, May, 2005     

早期干预对脑损伤大鼠学习记忆及神经生长因子的影响

目的:探讨早期干预对缺氧缺血性脑损伤(HIBD)大鼠学习记忆功能的影响及机制.方法:结扎SD大鼠一侧子宫角血管建立HIBD模型,采用早期触摸和丰富环境刺激进行早期干预,为期28天.以一次被动回避反应、脑干听觉诱发电位(BAEP)、神经生长因子(NGF)作为检测指标.结果:干预组大鼠(18只)被动回避反应步入潜伏期(STL)长于非干预组(15只);BAEP的Ⅱ、Ⅳ波潜伏期(PL)及Ⅰ～Ⅳ波峰间期(IPL)短于非干预组;脑组织内NGF的含量高于非干预组(P＜0.05).结论:早期干预可有效改善HIBD大鼠学习记忆功能;提高脑组织内源性NGF的水平是早期干预促进HIBD大鼠脑功能修复的机制之一.     

Neuroimmunological Aspects of Fetus and Newborn Brain Damage in Complicated Pregnancy

PROBLEM: The role of neuroautoimmune mechanisms in pathogenesis of perinatal damage of fetus and neonate brain during complicated pregnancy is considered to be important. METHOD: To determine neurospecific antigens (NSA) and their antibodies, ELISA and two-site column enzyme immunoassay were used. RESULTS: The contents of NSA and anti-brain antibodies, associated with fetal brain congenital development defects, account for the development of neuroautoimmune shifts in the mother-fetus system. The time of NSA appearance in serum from pregnant women, the dynamics of their level during pregnancy, and the appearance of anti-brain antibodies were determined, not by the nosology of extragenital pathology, but by the degree of fetus suffering, i.e., by the state of its central nervous system, connected with the decompensation of metabolic processes and homeostatic disorder in a mother-fetus system. CONCLUSIONS: Approved immunodiagnostic test systems should be recommended as markers for determination of pregnancy risk group, prognosticating perinatal pathology of neonatal and childhood CNS disorders.     

缺氧缺血性脑损伤后谷氨酸水平变化对少突胶质细胞的损伤

谷氨酸是哺乳动物中枢神经系统主要的兴奋性氨基酸,生理状态时,对中枢神经系统各种细胞的发育成熟具有重要作用。但在新生儿缺氧缺血性脑损伤(Hypoxic-Ischemic Brain Damage,HIBD)等病理情况下,脑室周围谷氨酸浓度升高,过度激活少突胶质细胞上的谷氨酸受体,导致少突胶质细胞损伤、死亡,继而使脑室周围白质软化,进一步引起HIBD患儿髓鞘化障碍,造成认知能力下降和远期行为学异常。本文主要综述谷氨酸对生理状态少突胶质细胞迁徙分化的影响及病理情况谷氨酸受体过度激活介导的少突胶质细胞损伤及机制。     

创伤性脑损伤活体脑片不同时相的脂质过氧化损伤

目的 观测创伤性脑损伤后不同时间大鼠脑组织的脂质过氧化损伤。方法 70只SD大鼠随机分为假损伤组（n=10）和脑损伤组，损伤组按伤后1、6、24、48、72和168h观察时间点分为6个亚组（n=10）。用Feeney氏自由落体撞击法制作重型颅脑损伤模型。利用激光扫描共聚焦显微镜观察损伤后不同时间荧光探剂2，7-二氯氢化荧光素（H2DCFDA）与碘化丙啶（PI）标记的活体脑片细胞内脂质过氧化物的动态变化和细胞死亡程度。结果 ①1、6、24h损伤组脂质过氧化物明显增加（P〈0．05），48h达到峰值，之后下降，72h已显著下降（P〈0．05），168h恢复正常水平。②1、6h损伤组神经细胞死亡明显增加（P〈0．05），24h达到峰值，之后维持不变，24、48、72及168h各损伤组之间细胞死亡无明显差异（P〉0．05）。③脂质过氧化物引起神经细胞死亡。结论 创伤性脑损伤早期（〈72h）脑组织即发生脂质过氧化反应引起神经细胞死亡，并且将持续一周。脂质过氧化物在创伤性脑损伤的继发损害中起重要作用。     

Localization Accuracy of Distributed Inverse Solutions for Electric and Magnetic Source Imaging of Interictal Epileptic Discharges in Patients with Focal Epilepsy

Distributed inverse solutions aim to realistically reconstruct the origin of interictal epileptic discharges (IEDs) from noninvasively recorded electroencephalography (EEG) and magnetoencephalography (MEG) signals. Our aim was to compare the performance of different distributed inverse solutions in localizing IEDs: coherent maximum entropy on the mean (cMEM), hierarchical Bayesian implementations of independent identically distributed sources (IID, minimum norm prior) and spatially coherent sources (COH, spatial smoothness prior). Source maxima (i.e., the vertex with the maximum source amplitude) of IEDs in 14 EEG and 19 MEG studies from 15 patients with focal epilepsy were analyzed. We visually compared their concordance with intracranial EEG (iEEG) based on 17 cortical regions of interest and their spatial dispersion around source maxima. Magnetic source imaging (MSI) maxima from cMEM were most often confirmed by iEEG (cMEM: 14/19, COH: 9/19, IID: 8/19 studies). COH electric source imaging (ESI) maxima co-localized best with iEEG (cMEM: 8/14, COH: 11/14, IID: 10/14 studies). In addition, cMEM was less spatially spread than COH and IID for ESI and MSI (p < 0.001 Bonferroni-corrected post hoc t test). Highest positive predictive values for cortical regions with IEDs in iEEG could be obtained with cMEM for MSI and with COH for ESI. Additional realistic EEG/MEG simulations confirmed our findings. Accurate spatially extended sources, as found in cMEM (ESI and MSI) and COH (ESI) are desirable for source imaging of IEDs because this might influence surgical decision. Our simulations suggest that COH and IID overestimate the spatial extent of the generators compared to cMEM.     

基于fMRI的原发全面性癫痫脑活动的局域一致性研究

癫痫是一种以神经活动同步性异常增高为特征的中枢神经系统疾病。我们利用基于局域一致性（regional homogeneity,ReHo）分析方法的功能磁共振成像（functional Magnetic Resonance Imaging,fMRI）技术对原发全面性癫痫（idiopathic generalized epilepsy,IGE）进行研究。观察IGE患者相比正常对照组局域一致性的改变情况。结果表明：在静息状态下,患者大脑的局域一致性在某些脑区较正常人低,主要集中在楔前叶、内侧前额叶、双侧颞叶、双侧额中回;另外,在某些脑区较正常人高,主要集中在底丘脑等中缝核团。提示该方法可检出癫痫活动造成的局部脑组织血氧水平依赖（blood oxygen level dependent,BOLD）信号同步性的改变,从而有助于原发全面性癫痫的病理生理机制的探索。     

Cellular Composition of the Piriform Cortex of the Rat Brain in Experimental Epilepsy

The cellular composition of all layers of the anterior, central, and posterior parts of the piriform cortex of the rat brain was studied two weeks and one month after specific electrical stimulation (kindling) of the ventral hippocampus. Stereomicroscopic analysis at both two weeks and one month after kindling showed significant decreases in the numbers of pyramidal cells and interneurons in all layers of all parts of the piriform cortex. At two weeks, the numbers of pyramidal cells and interneurons in the central part of the piriform cortex also decreased in rats in which electrodes were inserted into the ventral hippocampus but without stimulation. These results, along with published data, led to a series of suggestions regarding the involvement of the piriform cortex in epileptogenesis. __________ Translated from Morfologiya, Vol. 127, No. 1, pp. 14–17, January–February, 2005. director Dr M. G. Zhvaniya     

基于fMRI的原发全面性癫痫脑活动的局域一致性研究

癫痫是一种以神经活动同步性异常增高为特征的中枢神经系统疾病.我们利用基于局域一致性(regional homogeneity,ReHo)分析方法的功能磁共振成像(functional Magnetic Resonance Imaging, fMRI)技术对原发全面性癫痫(idiopathic generalized epilepsy, IGE)进行研究.观察IGE患者相比正常对照组局域一致性的改变情况.结果表明:在静息状态下,患者大脑的局域一致性在某些脑区较正常人低,主要集中在楔前叶、内侧前额叶、双侧颞叶、双侧额中回;另外,在某些脑区较正常人高,主要集中在底丘脑等中缝核团.提示该方法可检出癫痫活动造成的局部脑组织血氧水平依赖(blood oxygen level dependent, BOLD)信号同步性的改变,从而有助于原发全面性癫痫的病理生理机制的探索.