PKCγ免疫反应定位小鼠皮质脊髓束的实验研究

目的探讨显示皮质脊髓束在成年小鼠脑和脊髓中定位分布的简便有效方法。方法运用蛋白激酶Cγ（PKCγ）免疫组织化学染色法,观察成年ICR小鼠脑和脊髓中皮质脊髓束的定位和分布情况。结果PKCγ免疫阳性产物分布于大脑运动皮层第V层锥体细胞胞体和轴突中,锥体细胞的阳性纤维经内囊、中脑大脑脚底、脑桥基底部、下行至延髓锥体中。在延髓下段,PKCγ阳性纤维经锥体交叉后进入对侧脊髓灰质后联合背侧,形成背侧皮质脊髓束,在脊髓白质的后索腹侧深层下行,至骶髓3-4节段以下逐渐消失。在整个脊髓前索和外侧索中未见有PKCγ阳性纤维。结论PKCγ特异地表达于脊髓后索皮质脊髓束中,提示PKCγ免疫组织化学法是一种显示和观察皮质脊髓束精确定位的有效方法。     

电刺激促进大鼠正常和损伤脊髓内源性神经干细胞的增殖和分化

本文简要地回顾了半个世纪以来人们对于哺乳类动物中枢神经系统内源性神经干细胞（eNSCs）的认识。eNSCs和神经前体细胞的增殖与分化贯穿生命始终,而不是像传统学说所述的出生后神经细胞不再分裂。在脊髓,这些细胞将分化成熟的少突胶质及其它胶质细胞。作者基于近年来植入功能性电刺激器（FES）治疗脊髓损伤的研究工作,回顾了在正常或损伤的实验动物中,将FES植入大脑皮质或周围神经干可以增加脊髓内eNSCs的分化与增生,进而促进脊髓再髓鞘化及组织修复等研究进展。同时探讨了将eNSCs和FES的研究工作与针灸,尤其是电针治疗相结合的可能性。     

基于PSoC的脑电信号采集系统的设计

脑电信号是一种很重要的生物医学信号,它是临床医学诊断和脑科学研究的一种重要手段。本文介绍了基于Cypress PSoC~(TM)可编程片上系统的脑电信号采集系统的整个设计过程,包括硬件组成和软件设计方法。通过PSoC芯片特有的可编程模拟系统和数字系统,可以把大量的外围器件集成到芯片的内部,从而提高了硬件系统的集成度和可靠性;加上功能强大的PSOC Designer集成开发环境,提高了开发效率,而且系统的软硬件升级也更加容易了。     

用弥散张量成像检测猕猴大脑运动区占位病变对健侧皮质脊髓束的作用

因皮质脊髓束(corticospinal tract,CST)损伤而造成的运动功能丧失可得到一定恢复,但关于大脑运动区占位性病变对健侧CST结构功能影响的研究却相对较少。该研究采用两只健康猕猴行球囊置入术建立大脑运动区占位性病变模型,行4次磁共振弥散张量成像(diffusion tensor imaging,DTI)扫描,检测手术区对侧CST的FA值("各向异性"值),发现球囊置入术后当天,对侧CST的FA值无明显变化,但随时间的延长升高,球囊取出术后一周更为明显。实验表明该模型可行、可靠,从DTI观察到病变健侧CST出现代偿,即使占位解除短期内这一作用仍明显,提示健侧CST共同参与瘫痪肢体功能的恢复。     

新生大鼠脊髓神经干细胞的分离培养及鉴定

目的　从新生大鼠的脊髓中分离培养神经干细胞并观察其增殖和分化能力。方法　采用细胞培养技术结合间接免疫荧光细胞化学法。结果　分离的细胞生长旺盛 ,单克隆化生成的细胞团 ,BrdU掺入呈强阳性。分离培养获得的细胞团呈Nestin强阳性 ,至今已在体外连续传代 8个月。培养的细胞团经 1%小牛血清诱导可分化为神经元和星形胶质细胞。结论　成功分离培养了新生大鼠脊髓神经干细胞     

大鼠内侧前额叶皮质内ERK1/2 活化参与脊髓损伤后抑郁情绪

目的:观察细胞外信号调节激酶1/2(ERK1/2)的活化在脊髓损伤引起抑郁中的作用。方法:应用Western blot和行为药理学方法,观察脊髓损伤后(SCI)大鼠内侧前额叶皮质内(mPFC)ERK1/2及磷酸化-ERK1/2(p-ERK1/2)的表达情况及ERK1/2磷酸化抑制剂U0126对抑郁样行为的影响。结果:脊髓损伤后的第2天到第8周,SCI模型大鼠的BBB评分均显著低于假手术组,差异具有统计学意义(p0.05)。脊髓损伤后8周-12周,SCI模型大鼠强迫游泳不动时间与假手术组相比明显缩短,mPFC内pERK1/2蛋白表达水平明显升高,总ERK 1/2的蛋白水平则未见组间差异,而给予U0126的大鼠的不动时间与给药之前相比明显延长增加,mPFC内pERK1/2蛋白表达水平较SCI模型大鼠明显降低,差异均具有统计学意义(P0.05)。结论:内侧前额叶皮质内ERK1/2的激活参与了脊髓损伤后引起的突触可塑性,在相关的抑郁样行为的产生中发挥了重要的作用。     

多通道神经信号分析方法及其应用

在神经科学研究中,多通道记录方法被普遍应用在对神经元群体活动特性的研究中.通过分析多个神经元的活动,可以了解神经系统协同编码外界信息的规则以及大脑实现各项功能的机制.为了挖掘出多通道神经信号中携带的信息及其潜在的相关性,需要合适的计算方法辅助对神经元放电活动进行解码.本文回顾了多通道神经信号分析中的一些常见方法,以及它...     

Neuritin对大鼠急性脊髓损伤后神经中丝作用的研究

目的:探讨Neuritin对大鼠脊髓损伤后神经元突起再生的作用.方法:分为Neuritin组,His组和假手术组.使用改良Allen's打击法打击Neuritin组和His组大鼠T10或T11节段脊髓.Neuritin组和His组经蛛网膜下腔置管局部连续给予Neuritin和His蛋白(6ug/d)一周.假手术组仅咬除椎板不损伤脊髓,经蛛网膜下腔置空管而部损伤脊髓.术后6h、3d、7d、14d、28d、56d分别观察:①运动功能评分(BBB评分)观察大鼠后肢运动功能恢复情况;②HE染色观察脊髓组织形态学变化;③免疫组织化学染色和Western blotting检测损伤段脊髓神经中丝蛋白(NF200)的修复与再生.结果:①BBB评分,Neuritin组和His组在一周内没有明显差别,但Neuritin组和His组的评分均低于假手术组,从术后第14d,实验组评分明显高于对照组(P＜0.05);②HE染色可见损伤段脊髓出血、坏死及炎性细胞浸润;③免疫组化检测,Neuritin组的NF200平均光密度值(IOD/AREA)较His组明显增高(P＜0.05);Western blotting检测的NF200灰度值(GMD)较His组明显增高(P＜0.05),结论:持续外源性Neuritin能促进大鼠脊髓损伤后伤区神经元突起的再生,并能促进大鼠后肢运动功能的康复.     

红核脊髓运动诱发电位与脊髓损伤的关系

目的: 探讨一种可以敏感地反映脊髓损伤程度的客观、定量的电生理学指标.方法: 采用Wrathall等人描述的重力损伤法制备大鼠脊髓胸段(T8)分级损伤模型,通过测量损伤动物红核-脊髓运动诱发电位(MEPs)的变化,并与动物运动行为和组织形态学检查结果进行比较,分析红核-脊髓MEPs与脊髓分级损伤的关系.结果: 在给予红核刺激后,假损伤组红核-脊髓MEPs出现5～7个正波和4～5个负波,峰-峰总幅度值(简称总峰值)为(195.25±34.35)μV,峰潜伏时为(1.57±0.15)ms.随损伤程度加大,总峰值明显减少,而峰潜伏时明显延长.红核-脊髓MEPs总峰值与观察期末的BBB评分(r=0.79)以及损伤中心处的残余面积(r=0.87)显著相关;峰潜伏时与观察期末的BBB评分(r=-0.88)以及损伤中心处的残余面积(r=-0.86)也有显著的相关性.结论: 红核-脊髓MEPs总峰值和峰潜伏时两项指标可以敏感地反映脊髓分级损伤程度、运动功能和形态学情况,是监测胸段脊髓损伤程度的客观、定量、精细的电生理指标.     

Prediction of motor outcome using remaining corticospinal tract in patients with pontine infarct: Diffusion tensor imaging study

The aim of this study was to investigate the relationship between the remaining corticospinal tract (CST) as determined by diffusion tensor imaging (DTI) and 6-month motor outcome in patients with pontine infarct. Ratios of fractional anisotropy (FA), fiber number (FN), and CST area were calculated, and the FN ratio and CST area ratio showed significant correlation with all 6-month motor outcome. Thus, the remaining CST in the pons measured using DTI at early stage of stroke could predict motor outcome in patients with pontine infarct.     

Bilateral movement training promotes axonal remodeling of the corticospinal tract and recovery of motor function following traumatic brain injury in mice

Traumatic brain injury (TBI) results in severe motor function impairment, and subsequent recovery is often incomplete. Rehabilitative training is considered to promote restoration of the injured neural network, thus facilitating functional recovery. However, no studies have assessed the effect of such trainings in the context of neural rewiring. Here, we investigated the effects of two types of rehabilitative training on corticospinal tract (CST) plasticity and motor recovery in mice. We injured the unilateral motor cortex with contusion, which induced hemiparesis on the contralesional side. After the injury, mice performed either a single pellet-reaching task (simple repetitive training) or a rotarod task (bilateral movement training). Multiple behavioral tests were then used to assess forelimb motor function recovery: staircase, ladder walk, capellini handling, single pellet, and rotarod tests. The TBI+rotarod group performed most forelimb motor tasks (staircase, ladder walk, and capellini handling tests) better than the TBI-only group did. In contrast, the TBI+reaching group did not perform better except in the single pellet test. After the injury, the contralateral CST, labeled by biotinylated dextran amine, formed sprouting fibers into the denervated side of the cervical spinal cord. The number of these fibers was significantly higher in the TBI+rotarod group, whereas it did not increase in the TBI+reaching group. These results indicate that bilateral movement training effectively promotes axonal rewiring and motor function recovery, whereas the effect of simple repetitive training is limited.     

Three‐dimensional reconstruction of corticospinal tract using one‐photon confocal microscopy acquisition allows detection of axonal disruption in spinal cord injury

The principal motor tract involved in mammalian locomotor activities is known as the corticospinal tract (CST), which starts in the brain motor cortex (upper motor neuron), extends its axons across the brain to brainstem and finally reaches different regions of spinal cord, contacting the lower motor neurons. Visualization of the CST is essential to carry out studies in different kinds of pathologies such as spinal cord injury or multiple sclerosis. At present, most studies of axon structure and/or integrity that involve histological tissue sectioning present the problem of finding the region where the CST is predominant. To solve this problem, one could use a novel technique to make the tissues transparent and observe them directly without histological sectioning. However, the disadvantage of this procedure is the need of costly and non‐conventional equipment, such as two‐photon fluorescence microscopy or ultramicroscopy to perform the image acquisition. Here, we show that labeling the CST with FluoroRuby in the motor cortex and then performing the clearing technique, the z‐acquisition of the entire CST in unsectioned tissue followed by three‐dimensional reconstruction can be carried out by standard one‐photon confocal microscopy, with yields similar to those obtained by two‐photon microscopy. In addition, we present an example of the application of this method in a spinal cord injury model, where the disruption of CST is shown at the lesion site.

     

Changes of the corticospinal tract in the unaffected hemisphere in stroke patients: A diffusion tensor imaging study

We investigated changes of the corticospinal tract (CST) in the unaffected hemisphere according to severity of the CST injury, using diffusion tensor imaging (DTI). According to the severity of the CST injury in the affected hemisphere, the stroke patients showed different aspects of fiber volume increment of the CST in the unaffected hemisphere; the fiber volume was increased in the early phase in patients with mild injury of CST and later phase in patients with severe injury of CST.     

Axoplasmic flow of tritiated proline in the corticospinal tract of the rat

Summary The rates of axoplasmic transport were studied in the corticospinal tract of the rat by injecting tritiated proline into the sensory-motor cortex and subsequently analyzing the distribution of incorporated label in the spinal cord at intervals after injection. A mathematical model of the anatomy of the corticospinal tract was developed and used in analysis of the data. The rate of a fast component was calculated to be 240–420 mm per day, which is comparable with rates of fast components in the peripheral nervous system (PNS), but considerably greater than rates in other tracts in the central nervous system. A slow component was calculated to have a transport rate of 3–8 mm per day which is greater than rates found either in the CNS or PNS. This higher rate may be related to the greater length of the corticospinal tract as compared to other CNS tracts studied.This research was financed by the Veterans Administration research support awarded to Dr. Feringa by the Development Funds of the Department of Pathology, University of Michigan, and by the University of Michigan Medical Center Fund for Computing. The authors wish to express their appreciation to Ms. Linda Lee Austin for technical assistance, Ms. Diane Trakas and Ms. Barbara Reader for secretarial aid, and Mr. Richard Fritzler for assistance with graphics     

Recovery of instrumental conditioned reflexes in rats after pyramidotomy and action of bacterial melanin

Unilateral pyramidotomy at the bulbar level performed after preliminary elaboration of instrumental conditioned reflex (ICR) and without its elaboration caused hemiparesis of extremities in rats. Next day after this operation a half of the operated animals both with elaborated ICE and without its elaboration was injected intramuscularly with bacterial melanin solution (170 mg/kg). Comparison of terms of recovery of ICR and of a balancing movement of the paralyzed hindlimb in the operated rats without administration of melanin and with its injection showed that in the “melanin” animals the time of posttraumatic rehabilitation was much shorter and recovery of movement occurred faster and more completely. It has been found that the difference in terms of recovery of rat motor functions in this case is due to the protective action of bacterial melanin.     

Sensitively recorded breathing signals of rats and their nonlinear dynamics

Nonlinear dynamical properties of sensitively recorded breathing signals (SRBS), which include cardiac induced air flow pulsations so-called pneumocardiogram (PNCG) signals, are investigated, in this methodological study. For this purpose, we assessed the SRBS of laboratory rat. The nonlinear behaviors of SRBS were investigated by the reconstructing phase space, using the autocorrelation function and the false nearest neighbor method. The chaotic SRBS attractors were discussed from the point of view of the cardiopulmonary system. This method can be used to assess the heart performance and respiratory mechanics, and might be useful to design for the physiological studies of cardiorespiratory system in small laboratory animals.     

The relation between the motor evoked potential and diffusion tensor tractography for the corticospinal tract in chronic hemiparetic patients with cerebral infarct

We examined the relation between the results of transcranial magnetic stimulation (TMS) and diffusion tensor tractography (DTT) for the corticospinal tract (CST) in chronic hemiparetic patients with a middle cerebral artery (MCA) territory infarct. The amplitude of motor evoked potential (MEP) was closely related to the FN of the CST on DTT in chronic hemiparetic patients with an MCA infarct. We believe that our results would be helpful in more precise estimation of the CST.     

A distance-based dynamical transition analysis of time series signals and application to biological systems

This study demonstrates an application of distance-based numerical measures to the phase space of time series signals, in order to obtain a temporal analysis of complex dynamical systems. This method is capable of detecting alterations appearing in the characters of the deterministic dynamical systems and provides a simple tool for the real-time analysis of time series data obtained from a complex dynamical system even with black box functionality. The study presents a possible application of the method in the dynamical transition analysis of real EEG records from epilepsy patients.     

Discriminant analysis on cells from developing squamous cancer of the respiratory tract

Cytologic preparations made from the tracheobronchial tree taken by the Schreiber catheter have been scanned by three color microphotometry. The digitized cell images were processed by the analytical cytodiagnostic programs of the TICAS system. Cells were sorted into two control groups and five groups of increasing atypia ranging from normal epithelium to invasive squamous cell carcinoma. Standard statistical tests, including Wilk's Lambda, Rao's V, and the Kruskal-Wallis tests are performed on these subsets of cell image features. This study demonstrates that discriminant analyses permit differentiation between normal cells and those from marked atypia or carcinoma and that the classification achieves a high degree of agreement with visual assignment.