Abnormal medial prefrontal cortex connectivity and defective fear extinction in the presymptomatic G93A SOD1 mouse model of ALS

Amyotrophic lateral sclerosis (ALS) is a fatal progressive neuropathy associated with the degeneration of spinal and brainstem motor neurons. Although ALS is essentially considered as a lower motor neuron disease, prefrontal cortex atrophy underlying executive function deficits have been extensively reported in ALS patients. Here, we examine whether prefrontal cortex neuronal abnormalities and related cognitive impairments are present in presymptomatic G93A Cu/Zn superoxide dismutase mice, a mouse model for familial ALS. Structural characteristics of prelimbic/infralimbic (PL/IL) medial prefrontal cortex (mPFC) neurons were studied in 3-month-old G93A and wild-type mice with the Golgi–Cox method, while mPFC-related cognitive operations were assessed using the conditioned fear extinction paradigm. Sholl analysis performed on the dendritic material showed a reduction in dendrite length and branch nodes on basal dendrites of PL/IL neurons in G93A mice. Spine density was also decreased on basal dendrite segments of branch order five. Consistent with the altered morphology of PL/IL cortical regions, G93A mice showed impaired extinction of conditioned fear. Our findings indicate that abnormal prefrontal cortex connectivity and function are appreciable before the onset of motor disturbances in this model.     

Functional magnetic resonance imaging of the primary motor cortex in humans: response to increased functional demands

Functional magnetic resonance imaging (fMRI) studies have been performed on 20 right handed volunteers at 1.5 Tesla using echo planar imaging (EPI) protocol. Index finger tapping invoked localized activation in the primary motor area. Consistent and highly reproducible activation in the primary motor area was observed in six different sessions of a volunteer over a period of one month. Increased tapping rate resulted in increase in the blood oxygenation level dependent (BOLD) signal intensity as well as the volume/area of activation (pixels) in the contra-lateral primary motor area up to tapping rate of 120 taps/min (2 Hz), beyond which it saturates. Activation in supplementary motor area was also observed. The obtained results are correlated to increased functional demands.     

突触囊泡蛋白在ALS转基因鼠海马的表达变化

目的为了为揭示肌萎缩脊髓侧索硬化症（amyotrophic lateral sclerosis,ALS）认知功能障碍的机制提供依据,观察不同年龄ALS转基因小鼠海马中突触囊泡蛋白（synaptophysin,Syp）的表达情况。方法取95d、108d和122dALS转基因鼠海马,应用免疫荧光、Westernblot、RT-PCR技术检测Syp在海马中的表达变化。结果与同窝野生型鼠比较,Syp蛋白和mRNA表达水平在95d龄ALS转基因鼠海马中无明显变化,在108d与122d龄ALS转基因鼠海马中明显降低。结论Syp在ALS转基因鼠海马中表达减少表明,突触可塑性降低是ALS学习记忆能力下降的重要病理学基础。     

Thalamic input to motor cortex facilitates goal-directed action initiation

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Cytokine expression levels in ALS: A potential link between inflammation and BMAA-triggered protein misfolding

Recently, it has been shown that proinflammatory cytokines play a complex and important role in the pathogenesis of many neurological disorders, including amyotrophic lateral sclerosis (ALS). To help facilitate future discoveries and more effective treatment strategies, we highlight the role that both innate and adaptive immune systems play in ALS and summarize the main observations that relate to cytokine expression levels in this disease. Furthermore, we propose a mechanism by which a known neurotoxin, β-N-methylamino-l-alanine (BMAA), may trigger this cytokine expression profile through motor neuron protein misfolding and subsequent NLRP3 (nucleotide-binding domain (NOD)-like receptor protein 3) inflammasome activation.     

Signals in pathological CNS extracts of ALS mice promote hMSCs neurogenic differentiation in vitro

The capability of MSCs to differentiate into neurons has been proven by many studies. Recently, other studies have cast doubt on MSCs neurogenic differentiation with non-physiological chemical inducing agents in vitro. This present study was designed to use conditioned medium to investigate whether signals from pathological condition of ALS were competent to induce a program of neurogenic differentiation in expanded cultures of hMSCs. Incubation of hMSCs with conditioned medium prepared from CNS extracts of ALS mice (SOD1-G93A ALS mice) resulted in a time-dependent morphological change from fibroblast-like into neuron-like, concomitant with increase in the expression of Nestin and subsequent beta-tubulin III, NSE and GAP43. Moreover, signals in pathological CNS extracts of ALS mice were more effective in promoting hMSCs neurogenic differentiation than those in physiological extracts of normal adult mice. These results show that pathological condition of ALS is endowed with capacity to induce hMSCs neurogenic differentiation and hMSCs have shown a potential candidate in cellular therapy for ALS.     

3 例以延髓麻痹为首发表现的肌萎缩侧索硬化的病例报告

目的:探讨以延髓麻痹为首发症状的肌萎缩侧索硬化的临床特点。方法:报告3例以构音障碍等延髓麻痹症状起病的肌萎缩侧索硬化少见病例,结合文献复习,分析其临床特点。结果:在ALS患者中,以延髓麻痹为首发症状发生率相对较低,多见于老年人,最易表现为构音障碍,患者的生存期缩短,预后不良。结论:对于以延髓麻痹表现起病的ALS患者,要引起重视,及时针对延髓麻痹对症治疗,改善患者生活质量。     

Establishment of a cell model of ALS disease: Golgi apparatus disruption occurs independently from apoptosis

The Golgi apparatus (GA) appears disrupted in motor neurons of amyotrophic lateral sclerosis (ALS). Here, mouse motor neuron-like NSC-34 cell lines stably expressing human superoxide dismutase 1 (hSOD1)^wt and mutant hSOD1^G93A, as an ALS cell model, were constructed. The number of cells with disrupted GA increased from 14% to 34%. Furthermore, NSC-34/hSOD1^G93A cells showed lower levels of proliferation and differentiation. GA disruption was not caused by apoptosis as determined by several techniques including caspase-3 activation. Similarly, spinal cords from ALS patients did not show caspase-3 activation. Therefore, NSC-34/hSOD1^G93A cells are a suitable cell model to study GA dysfunction in ALS.     

ALS转基因小鼠脊髓中miRNA-132表达减少BDNF表达增加

目的研究miRNA-132和脑源性神经营养因子(brain derived neurotrophic factor,BDNF)在肌萎缩侧索硬化症(amyotrophic lateral sclerosis,ALS)转基因小鼠脊髓中的表达变化,探讨miRNA-132、BDNF在ALS发病中的作用。方法取SOD1-G93A ALS转基因鼠发病早期(95d)、中期(108d)和晚期(122d)脊髓组织,应用qRT-PCR及原位杂交(hybridization in situ, ISH)技术检测miRNA-132的表达及定位,应用qRT-PCR及Western blot技术检测BDNF在mRNA及蛋白水平变化,免疫荧光技术检测BDNF在脊髓中的表达及分布,以同窝野生型鼠作为对照。结果与野生型鼠比较,miRNA-132在ALS转基因鼠脊髓组织表达下降,miRNA-132阳性信号主要定位脊髓前角细胞胞体;在ALS转基因鼠脊髓组织BDNF mRNA及蛋白水平均增高,BDNF免疫阳性细胞主要表达于脊髓前角神经元,表达信号明显增强。结论 miRNA-132、BDNF可能在ALS发病过程中发挥了重要作用。     

运动想象的脑机制及其在运动功能康复中应用的研究进展

运动想象对大脑相关功能有明显的改善作用,目前正在大量应用于运动训练和康复治疗领域.近年来随着诸如功能磁共振等成像工具的出现,神经成像的复杂程度得到了不断提高,从而推动了人们对运动想象的脑机制尤其是涉及多脑区之间的协同作用机制的认识逐步深入.针对运动想象的多脑区之间相互协作机制及运动想象在运动功能康复中的应用作了详细介绍.     

Current density threshold for the stimulation of neurons in the motor cortex area

The aim of this study was to determine a current density threshold for exciting the motor cortex area of the brain. The current density threshold for excitation of nerve fibres (20 microm in diameter) found in the literature is approximately 1 A/m(2) at frequencies lower than 1 kHz. In consideration of a safety factor of 100, the International Commission on Non-Ionizing Radiation Protection (ICNIRP) recommends to restrict the exposure to 0.01 A/m(2). The electromagnetic stimulation of neurons in the motor cortex is used in the clinical diagnosis of nerve lesions and neuropathy by means of magnetic or electrical transcranial stimulation. Combining medical data from clinical studies and technical specifications of the Magstim Model 200 stimulator, we were able to compute the current density threshold for the excitation of the human motor cortex by means of the finite element method (FEM). A 3D-CAD head model was built on the basis of magnetic resonance imaging (MRI) slices and segmented into four anatomical structures (scalp, skull, brain, and ventricular system) with different conductivities. A current density threshold for the stimulation of the motor cortex area of the upper limbs of 6 and 2.5 A/m(2) at 2.44 kHz and 50 Hz, respectively, was calculated. As these values lie above the recommended ICNIRP values by two orders of magnitude there is no need for lower safety standards with regard to stimulation of the brain.     

Acid sphingomyelinase inhibition improves motor behavioral deficits and neuronal loss in an amyotrophic lateral sclerosis mouse model

Amyotrophic lateral sclerosis (ALS) is an incurable neurodegenerative disease characterized by the degeneration of motor neurons in the spinal cord. Main symptoms are manifested as weakness, muscle loss, and muscle atrophy. Some studies have reported that alterations in sphingolipid metabolism may be intimately related to neurodegenerative diseases, including ALS. Acid sphingomyelinase (ASM), a sphingolipid-metabolizing enzyme, is considered an important mediator of neurodegenerative diseases. Herein, we show that ASM activity increases in samples from patients with ALS and in a mouse model. Moreover, genetic inhibition of ASM improves motor function impairment and spinal neuronal loss in an ALS mouse model. Therefore, these results suggest the role of ASM as a potentially effective target and ASM inhibition may be a possible therapeutic approach for ALS.     

Analysis of smoking and LPO in ALS

Smoking has been suggested as one of the risk factor for amyotrophic lateral sclerosis (ALS) development. In order to investigate whether adverse effects of cigarette smoke in ALS have any association with increase in oxidative stress, disease severity, lipid hydroperoxides (LPO) and superoxide dismutase-1 (SOD1) levels were measured in biofluids of smoker and never smoker ALS patients and clinically correlated. Serum and CSF from sporadic ALS patients (n = 50) diagnosed with El Escorial criteria were collected in the study. Serum (n = 50) and CSF (n = 42) were also collected from normal healthy controls. The LPO levels were estimated using commercially available kits. Enzyme-linked immunosorbent assays (ELISAs) were used to quantitate SOD1. Their levels were further analyzed among smoker and never smoker subjects. Significantly elevated LPO in sera and CSF of ALS patients were observed (p < 0.05). There was considerably increased LPO in sera and CSF of smoker ALS subjects matched with disease severity as compared to never smoker ALS (p < 0.05). ALS group did not show any alteration in SOD1 when compared to controls (p > 0.05). In addition, no change has been observed in SOD1 levels in ALS subjects who smoke (p > 0.05). Increased LPO and unaltered SOD1 in ALS patients may suggest the neuro-pathological association of LPO with ALS disease independent of SOD1. With current findings, it may be proposed that LPO levels might constitute as probable biomarker for smoker ALS patients, however, it cannot be concluded without larger gender matched studies. Additional investigations are needed to determine whether LPO upregulation is primary or secondary to motor neuron degeneration in ALS.     

正常人长时数字记忆信息提取的神经基础的功能磁共振研究

本文旨在通过功能磁共振成像(functional magnetic resonance imaging,fMRI)技术研究正常人进行长时数字记忆信息提取的神经基础。选取22名右利手志愿者进行长时数字记忆任务实验,采用组块设计,记忆任务与对照任务交替进行,同时利用Siemens 1.5T超导型磁共振仪进行fMRI成像,采用SPM99软件进行数据分析,脑功能区定位在Talairach坐标中显示。结果显示被试者在进行长时数字记忆提取任务时,激活最显著的皮层是左侧额中回(Brodmann分区9区,BA9区),另外左额叶内侧回、左额下回、右额下回、扣带回、左顶下小叶、左顶上小叶、右顶上小叶、右颞中回、左枕舌回、左枕中回、右中脑、小脑、右尾状核尾部等结构也有激活,各大脑皮层的激活均呈现明显的左侧半球优势。根据上述结果推论,长时数字记忆由以左侧大脑半球为优势的各脑区共同参与完成,其中左侧额叶外侧面可能是信息提取的重要结构,而其它脑叶及其之间的广泛联系可能在数字信息的加工、处理和存储中起重要作用。     

Caspase-1 and -3 mRNAs are differentially upregulated in motor neurons and glial cells in mutant SOD1 transgenic mouse spinal cord: a study using laser microdissection and real-time RT-PCR

Amyotrophic lateral sclerosis is characterized by selective motor neuron degeneration. An apoptotic pathway is thought to be involved. It is difficult, however, to analyze the molecular pathogenic mechanism in single motor neurons because of complexity in the neural tissue, which consists of multiple lineages of cells neighboring motor neurons. We quantified the caspase-1 and -3 mRNA in single motor neurons and neighboring glial cells isolated from the spinal ventral horn of mutant SOD1 transgenic (Tg) mice and littermates. Motor neurons and neighboring glial cells were isolated from spinal sections by laser microdissection, and the mRNAs were quantified by RT-PCR. In the Tg mice, caspase-1 mRNA was first upregulated in motor neurons and second in glial cells. The caspase-3 mRNA was increased in motor neurons following the caspase-1 mRNA. These results indicated that caspase-1 and -3 mRNAs are differentially upregulated in motor neurons and glial cells of the Tg mice, and that mRNAs in isolated cells can be accurately assessed using our procedures.     

经颅电刺激对睡眠剥夺后双侧后扣带回皮质功能连接紊乱干预作用的初步研究

目的:探讨经颅电刺激对睡眠剥夺后双侧后扣带回皮质功能连接紊乱的干预作用。方法:研究采用自身前后对照的试验设计。16名受试者均接受2次24 h睡眠剥夺,2次睡眠剥夺间隔3周,受试者分别于第1次正常睡眠后、24 h睡眠剥夺后、经颅电刺激(真或假刺激)干预后(真、假刺激电流大小均为1 mA,电流作用时间分别为20 min、2 s,干预实验均持续20 min)及第2次经颅电刺激(假或真刺激)干预后采集静息态磁共振成像数据。以睡眠剥夺前收集静息态功能磁共振数据作为基线,选取双侧后扣带回皮质作为种子点进行全脑功能连接分析,观察睡眠剥夺前后及经颅电刺激真、假刺激后大脑的功能连接变化。结果:与正常睡眠后相比,24 h睡眠剥夺后双侧后扣带回皮质与双侧丘脑间的功能连接上升(P<0.01),与右侧楔前叶、海马旁回以及双侧岛叶间的功能下降(P<0.01)。与假刺激相比,给予真刺激后左侧后扣带回皮质与右侧楔前叶功能连接上升(P<0.01);与双侧丘脑、岛叶及右侧大脑皮质功能连接下降(P<0.01)。右侧后扣带回皮质与全脑的功能连接在双侧丘脑、右侧岛叶及大脑皮层间也存在下降(P<0....     

Different motor learning effects on excitability changes of motor cortex in muscle contraction state

Abstract

We aimed to investigate whether motor learning induces different excitability changes in the human motor cortex (M1) between two different muscle contraction states (before voluntary contraction [static] or during voluntary contraction [dynamic]). For the same, using motor evoked potentials (MEPs) obtained by transcranial magnetic stimulation (TMS), we compared excitability changes during these two states after pinch-grip motor skill learning. The participants performed a force output tracking task by pinch grip on a computer screen. TMS was applied prior to the pinch grip (static) and after initiation of voluntary contraction (dynamic). MEPs of the following muscles were recorded: first dorsal interosseous (FDI), thenar muscle (Thenar), flexor carpi radialis (FCR), and extensor carpi radialis (ECR) muscles. During both the states, motor skill training led to significant improvement of motor performance. During the static state, MEPs of the FDI muscle were significantly facilitated after motor learning; however, during the dynamic state, MEPs of the FDI, Thenar, and FCR muscles were significantly decreased. Based on the results of this study, we concluded that excitability changes in the human M1 are differentially influenced during different voluntary contraction states (static and dynamic) after motor learning.     

Astrocytes in amyotrophic lateral sclerosis: direct effects on motor neuron survival

Selective motor neuron death during amyotrophic lateral sclerosis (ALS) is a non-cell autonomous process in which non-neuronal cells induce and/or contribute to the disease process. The non-neuronal cells that are clearly involved in the pathogenesis of the disease are the surrounding astrocytes. Under normal conditions, astrocytes remove glutamate from the synaptic cleft and release trophic factors. In addition, these cells determine the functional characteristics of motor neurons. Recent evidence suggests that activation of astrocytes in a degenerative disease like ALS disturbs the crosstalk between astrocytes and motor neurons, which could contribute to and/or accelerate selective motor neuron death. These new insights may contribute to the development of therapeutic approaches to slow this fatal neurodegenerative disease.