缺血性脑卒中的皮质脊髓束的病理生理与干预研究

缺血性脑卒中是危害人类健康的常见疾病之一,具有高致死率和高致残率.近年来其发病率逐年上升,且有年轻化趋势.缺血性脑卒中急性发作后遗留的肢体运动功能障碍严重影响患者的生活质量,并且还影响患者其他功能的康复,给社会和家庭带来沉重负担.近年来的研究表明,皮质脊髓束作为大脑支配肢体随意运动的关键通路,其在脑卒中后继发的病理变化及重塑,可能在神经功能的恢复中占有重要地位,这就为缺血性脑卒中的恢复期及后遗症期治疗提供了新的思路.     

人脑皮质脊髓束的年龄相关变化

We don't have Chinese abstract. However, If you need abstract in Chinese. I'll make the abstract in chinese and attach it     

Dynamic mapping of the corticospinal tract in open cordotomy and myelomeningocele surgery

ObjectSpinal cord surgeries carry a high risk for significant neurological impairments. The initial techniques for spinal cord mapping emerged as an aid to identify the dorsal columns and helped select a safe myelotomy site in intramedullary tumor resection. Advancements in motor mapping of the cord have also been made recently, but exclusively with tumor surgery. We hereby present our experiences with dynamic mapping of the corticospinal tract (CST) in other types of spinal cord procedures that carry an increased risk of postoperative motor deficit, and thus could directly benefit from this technique.Case reportsTwo patients with intractable unilateral lower extremity pain due to metastatic disease of the sacrum and a thoraco-lumbar chordoma, respectively underwent thoracic cordotomy to interrupt the nociceptive pathways. A third patient with progressive leg weakness underwent cord untethering and surgical repair of a large thoracic myelomeningocele. In all three cases, multimodality intraoperative neurophysiologic testing included somatosensory and motor evoked potentials monitoring as well as dynamic mapping of the CST.ConclusionCST mapping allowed safe advancement of the cordotomy probe and exploration of the meningocele sac with untethering of the anterior-lateral aspect of the cord respectively, resulting in postoperative preservation or improvement of motor strength from the pre-operative baseline. Stimulus thresholds varied likely with the distance between the stimulating probe and the CST as well as with the baseline motor strength in the mapped myotomes.     

The corticospinal tract in Sturge-Weber syndrome: a diffusion tensor tractography study

OBJECTIVE: To utilize diffusion tensor tractography and evaluate the integrity of the corticospinal tract in children with unilateral Sturge-Weber syndrome (SWS). METHODS: Sixteen children (age: 1.5-12.3 years) with SWS involving one hemisphere and varying degrees of motor deficit, underwent magnetic resonance imaging (MRI) as part of a prospective clinical research study. Diffusion tensor imaging (DTI) was obtained and fiber tracking of the corticospinal tract was performed yielding average FA and ADC values along the pathway. These values were compared between the two hemispheres (affected vs. unaffected) and also correlated with the degree of motor deficits, after correction for age. RESULTS: Corticospinal tract FA values on the side of the affected hemisphere were lower (p=0.008) and ADC values were higher (p=0.011) compared to the normal side. Furthermore, FA and ADC values on the side of the angioma did not show the normal age-related variations, which the contralateral corticospinal pathway values did demonstrate. Although none of the patients had severe hemiparesis, those with moderate motor deficit had increased ADC values, as compared to those with mild (p=0.009) or no motor deficit (p=0.045). CONCLUSION: MRI with DTI shows abnormalities of the corticospinal tract in children with SWS even before severe motor impairment develops. Thus, DTI can be a clinically useful method to evaluate the integrity of the corticospinal tract in young children who are at risk for progressive motor dysfunction.     

The corticospinal tract of amyotrophic lateral sclerosis--a morphometric analysis of the myelinated fibers]

The myelinated fibers in the lateral corticospinal tract at the C6, T7, L4 levels in amyotrophic lateral sclerosis (ALS) and control cases were morphometrically examined. ALS cases consisted of 6 males and 2 females with ages ranging between 48 and 85 years, and were all the common or bulbar form in clinical manifestation. As for controls, 10 cases who died of non-neurological diseases, with age ranging 36 to 90 years were served. The population and the diameter profile of the myelinated fibers in the corticospinal tract of the C6, T7, L4 levels were measured by the method previously described and expressed as number per mm2. In control subjects, fiber-size histograms of myelinated fibers showed a bimodal pattern with a sharp peak of small fibers (less than 7.28 microns) and a broad peak of large fibers (greater than or equal to 7.28 microns) in all the spinal levels. In ALS cases, large myelinated fibers were predominantly diminished in number, a small myelinated fibers were also decreased in some cases. The degree of fiber loss was extremely variable among cases; well populated in large fibers in some cases. As for the rostral caudal distribution of myelinated fiber loss, a caudally-accentuated fiber loss particularly in large fiber was seen in some of the cases. The topographical distribution of fiber loss in the horizontal plane of the corticospinal tract in ALS did not show a distinctive pattern.     

Splanchnic preganglionic neurons in man: II. Morphometry of myelinated fibers of T7 ventral spinal root

Summary The T7 ventral spinal root (VSR) was obtained under optimal conditions in 12 human cases. The number and diameter histogram of myelinated fibers per VSR were obtained from sampled photographic enlargements of tranverse sections of nerve embedded in epoxy. A trimodal diameter histogram was consistently obtained. Based on available evidence, most of the fibers of the large diameter peak probably are alpha motoneuron axons, most of the intermediate diameter peak probably are gamma motoneuron axons and most of the small diameter peak are preganglionic autonomic axons. The preganglionic fiber peak was at 2.5 m and had, on the average 4198 fibers. The number of preganglionic fibers reliably reflected the intermediolateral column neuron cell body (ILC) counts previously done on the same cases at the corresponding level-in itself evidence that these tibers are axons of ILC neurons. There was a statistically significant attrition of preganglionic fibers with age. On the average, there was a loss of 340 fibers (8%) per decade, which is identical to the per cent of autonomic cytons lost per decade. This progressive attrition may provide the morphological basis for the postural hypotension of old age. The values obtained also provide important normative data for the three-dimensional pathologic and morphometric evaluation of the splanchnic preganglionic neurons in various neurologic disorders.This investigation was supported in part by NIH grant NSO 5811, MDA Center Grant, Mayo Foundation and Upton, Herrick, Schmitter and Gallagher Funds. Dr. Low was supported in part by followships of the Royal Australasian College of Physicians and the Postgraduate Medical Foundation, University of Sydney, Australia     

Age-related changes in the cerebellum: parallel fibers

Between the ages of 3 and 23 months, the cerebella of NIH Fischer 344 rats lose 30% of the thickness of the molecular layer, 60% of the length of parallel fibers, and 80% of the synaptic varicosities along parallel fibers. Nearly 60% of these synaptic varicosities disappear between 3 and 9 months. Thus, the loss of cerebellar synapses is unusual, may have begun early in life, and continue into old age, causing profound synaptic losses in older rats. In addition to serious implications to functional losses, we speculate that these synaptic losses may trigger other age-related cellular losses in the cerebellum.     

Assessing behavioural function following a pyramidotomy lesion of the corticospinal tract in adult mice

We have developed a pyramidotomy model in mice to lesion the corticospinal tract at the level of the brainstem pyramidal tract, and evaluated the resultant impairments in motor function in a series of behavioural tests. Adult C57BL/6 mice received a unilateral pyramidotomy and a control group of mice underwent sham surgery. We studied the effects of this lesion on forepaw function using five behavioural paradigms, some of which have been widely used in rat studies but have not been fully explored in mice. The tests used were: a rearing test, which assesses forepaw use for weight support during spontaneous vertical exploration of a cylinder; a grid walking test, which assesses the ability to accurately place the forepaws during exploration of an elevated grid; a tape-removal test, which measures both sensory and motor function of the forepaw; a CatWalk automated gait analysis, which provides a number of quantitative measures including stride length and stride width during locomotion; and a staircase reaching task, which assesses skilled independent forepaw use. All tests revealed lesion effects on forepaw function with the tape removal, grid walking, rearing and CatWalk tests demonstrating robust effects throughout the testing period. The development of a pyramidotomy lesion model in mice, together with behavioural tests which can reliably measure functional impairments, will provide a valuable tool for assessing therapeutic strategies to promote regeneration and plasticity.     

Unmyelinated corticospinal axons in adult rat pyramidal tract. An electron microscopic tracer study

The aim of the present study was to provide experimental ultrastructural evidence for a corticospinal component in the adult rat pyramidal tract (PT). For this purpose, the entire sensorimotor and frontal cortex of the left hemisphere was labelled using the anterograde tracer horseradish-peroxidase (HRP). Six months old rats were sacrificed 24 or 48 h after implantation of 6–8 HRP-gels. The detection of anterogradely transported HRP at the cervical as well as the lumbar intumescence was carried out as described earlier (J. Histochem. Cytochem., 35 [1987] 623–626). Our results demonstrate the occurrence of labelled myelinated as well as labelled unmyelinated axons within the adult rat PT at both spinal cord levels analyzed. This implicates that at least part of the unmyelinated profiles in the adult rat PT belong to fibres originating in the cortex and therefore must be interpreted as corticospinal axons. The findings are discussed in the light of their physiological significance.     

The lateral corticospinal tract and spinal ventral horn in X-linked recessive spinal and bulbar muscular atrophy: a quantitative study

A quantitative study was performed on spinal cord lesions in seven patients with X-linked recessive spinal and bulbar muscular atrophy. The myelinated fiber density of the lateral corticospinal tracts at the T7 cord level was well preserved for both large and small myelinated fibers. On the other hand, neurons in the L4 ventral horn were markedly depleted; marked loss was noted of the large alpha and medium-sized gamma motor neurons located in the lateral and medial nuclei as well as the small neurons in the intermediate zones of the ventral horn. These results suggest that myelinated fiber density and fiber-size distribution in the corticospinal tract are well preserved and that neuronal loss in the ventral horns is not restricted to alpha and gamma motoneurons but also involves small interneurons. Received: 8 May 1996 / Accepted: 31 July 1996     

Development of the corticospinal tract in the mouse spinal cord: a quantitative ultrastructural analysis

The growth of corticospinal tract (CST) axons was studied quantitatively at the 7th cervical (C7) and the 4th lumbar (L4) spinal segments in the balb/cByJ mice at the ages of postnatal day (P) 0, 2, 4, 6, 8, 10, 14, and 28. The cross-sectional area of the CST increased progressively with time. Unmyelinated axons, the most prominent CST element during early development, reached maximum at C7 and L4 on P14. Two phases of increase in the number of unmyelinated axons were observed at C7, while only one surge of axonal outgrowth was found at the L4 level. Pro-myelinated axons, defined as axons surrounded by only one layer of oligodendrocytic process, were first seen at P2 and P4 in the C7 and the L4 level, respectively, followed by a dramatic increase in the number of myelinated axons from P14 onwards at both spinal levels. Myelination of the CST axons occurred topographically in a dorsal-to-ventral pattern. The number of growth cones increased rapidly at the C7 level to reach its maximum at P4, while those at L4 increased steadily to the peak at P10. Growth cones with synapse-like junctions were occasionally observed in the growing CST. Degenerating axons and growth cones partly accounted for the massive axon loss at both spinal segments during CST development. Overall, the mouse CST elements changed dynamically in numbers during postnatal development, suggesting a vigorous growing and pruning activity in the tract. The mouse CST also showed a similar growth pattern to that of the rat CST.     

Callosal and corticospinal tract function in patients with hydrocephalus: a morphometric and transcranial magnetic stimulation study

In 15 patients with symptomatic hydrocephalus, pressure-induced morphological changes of the brain and the function of callosal and corticospinal fibres were studied. Morphometry of the corpus callosum (CC) was performed on midsagittal MR images. Focal transcranial magnetic stimulation of the motor cortex was used to assess simultaneously excitatory motor responses in contralateral hand muscle (corticospinally mediated effect) and inhibition of tonic EMG activity in ipsilateral hand muscles (transcallosal inhibition (TI) of the contralateral motor cortex). Before a shunt operation, the midsagittal area of the CC was reduced by 34% on average. The height and, to a lesser degree the length, of the CC were increased before the shunt operation. Thresholds and central motor latencies of corticospinally mediated responses were normal, response amplitudes were smaller than in normal subjects. Motor thresholds increased from 38, SD 5 to 52, SD 8% (P<0.01) within 7 days after ventricular drainage, reflecting the increase in the distance between stimulation coil and brain. The threshold increase paralleled a restoration of normal anatomical conditions within 7 days after shunt operation and the improvement of motor symptoms and might be a predictor of successful decompression. Transcallosal inhibition could be elicited in all patients. The measurements of TI lay within the normal range except the duration, which was prolonged in 73% of 15 patients before shunt operation as a probable indicator of an increased dispersion of callosal conduction. The normalization of the area and shape of the CC after shunt operation and the normal corticospinal and callosal conduction times exclude degeneration, demyelination or functional block of a large proportion of callosal or corticospinal tract fibres or a substantial loss of nerve cells in motor cortex. Received: 22 October 1997 Received in revised form: 13 January 1998 Accepted: 17 January 1998     

Motor outcome of deep intracerebral haemorrhage in diffusion tensor imaging: comparison of data from different locations along the corticospinal tract

Abstract

Objectives:

Although diffusion tensor imaging (DTI) is widely studied to assess the motor outcome after ischaemic stroke, there is paucity of data regarding outcomes of intracerebral haemorrhage (ICH). The aim of this study was to determine the DTI data from different locations along the corticospinal tract (CST) and association to motor outcome.

Methods:

We prospectively recruited patients with deep ICH admitted to our hospital from November 2010 to July 2012.Diffusion tensor imaging was performed within 14?days after the onset of ICH. Fractional anisotropy (FA) was measured along the CST at corona radiata, perihaematomal oedema, cerebral peduncle and pons. Corticospinal tract integrity was classified into three types by diffusion tensor tractography (DTT): type A with preserved CST, type B with partially interrupted CST and type C with completely interrupted CST. Motor outcome was assessed by Motricity index (MI) at admission, after 1 and 3?months.

Results:

Forty-eight patients were enrolled with a mean age of 62?years. The median time interval from onset of ICH to DTI study was 7?days. The patients in type C had significantly worse MI at admission (P?<?0.001), after 1?month (P?<?0.001) and after 3?months (P?<?0.001) as compared to those with type A and type B. Lower rFA at the corona radiata was significantly correlated with poorer motor outcome at admission, after 1?month and after 3?months.

Discussion:

Clinical motor outcome of ICH within 2?weeks can be identified with a statistically significant decrease in rFA at the corona radiata.     

Developmental abnormalities of corticospinal tract neurons in prenatally irradiated rats: a study using retrograde labeling with fast blue and intracellular lucifer yellow staining

The effect of prenatal X-irradiation on the ontogenesis of corticospinal tract (CST) neurons was examined in rats using retrograde labeling with Fast blue and intracellular Lucifer yellow staining. In prenatally irradiated rats, the cortical laminar architecture of the CST neurons was confused and many cells demonstrated migratory disturbances. Migratory-disordered CST neurons at deeper cortical levels resembled pyramidal cells, but their apical dendrites were oriented in various directions and the development of their dendrites was poor. Migratory-disordered CST neurons near the ependymal layer demonstrated round somata and many thin dendrites with spokewise radiation, suggesting a maturation disturbance. These results suggested that prenatal X-irradiation impeded the migration and maturation of CST neurons. These findings may form the basis for analyzing the mechanisms of radiation-induced mental retardation and behavioral changes.     

A quantitative study on changes of the myelinated fibers in the cerebral cortex of cortical dysplasia rats

An animal model of cortical dysplasia was established through X-ray irradiation induced subcortical heterotopic nodules in rats. Transmission electron microscopy detection of the ultrastructure and the stereology examination showed that there was a significant decrease in cerebral white matter and hippocampal volume, the total volume, volume density, length density and total length of the myelinated fibers in the white matter of cortical dysplasia rats. Subcortical heterotopic nodules of the hippocampal CA1 region and synaptic number density in the CA3 region were reduced compared with normal rats. Our experimental findings indicate that erosed subcortical heterotopic nodules, decreased total length of myelinated nerve fibers and demyelination directly lead to a reduction of white matter volume.     

Axonal swellings in the corticospinal tracts in amyotrophic lateral sclerosis

Summary In 2 of 16 cases with sporadic amyotrophic lateral sclerosis (ALS) large numbers of axonal swellings were observed in the corticospinal tracts over a region extending from the posterior limbs of internal capsules to the bulbar pyramids. On electron microscopy, these axonal swellings were seen to consist of accumulations of neurofilaments and altered neuronal organelles (mitochondria and secondary lysosomes). Their morphology differed from the spheroids seen in the anterior horn in ALS.     

Quantitative assessment of forelimb motor function after cervical spinal cord injury in rats: relationship to the corticospinal tract

Approximately 50% of human spinal cord injuries (SCI) are at the cervical level, resulting in impairments in motor function of the upper extremity. Even modest recovery of upper extremity function could have an enormous impact on quality of life for quadriplegics. Thus, there is a critical need to develop experimental models for cervical SCI and techniques to assess deficits and recovery of forelimb motor function. Here, we analyze forelimb and forepaw motor function in rats after a lateral hemisection at C5 and assessed the relationship between the functional impairments and the extent of damage to one descending motor system, the corticospinal tract (CST). Female Sprague-Dawley rats were trained on various behavioral tasks that require the forelimb, including a task that measures gripping ability by the hand (as measured by a grip strength meter, GSM), a food reaching task, and horizontal rope walking. After 8 weeks of post-injury testing, the distribution of the CST was evaluated by injecting BDA into the sensorimotor cortex either ipsi- or contralateral to the cervical lesion. Complete unilateral hemisection injuries eliminated the ability to grip and caused severe impairments in food retrieval by the forepaw ipsilateral to the lesion. There was no indication of recovery in either task. In cases in which hemisections spared white matter near the midline, there was some recovery of forelimb motor function over time. Assessment of rope climbing ability revealed permanent impairments in forelimb use and deficits in hindlimb use and trunk stability. Sensory testing using a dynamic plantar aesthesiometer revealed that there was no increase in touch sensitivity in the affected forelimb. For the cases in which both histological and behavioral data were available, spared forelimb motor function was greatest in rats in which there was sparing of the dorsal CST.     

麻醉复苏期大鼠皮质脊髓束神经电信号特征差异实验研究

目的 观察麻醉复苏过程中大鼠皮质脊髓束(CST)神经电信号放电频率、波幅、峰间期(ISI)等的变化,描述并分析麻醉复苏期大鼠CST神经电信号的特征差异. 方法 在复合麻醉剂Chlorpent麻醉后SD大鼠的脊髓T8节段处的CST内插入微电极,分别在麻醉后1h、2h、3h应用神经信号采集处理系统Cerebus记录大鼠CST神经电信号,利用神经信号分析软件Neuro Explorer及Off-line Sorter分析并比较CST神经电信号放电频率、波幅、ISI的变化. 结果 与麻醉后1 h(麻醉状态)比较,麻醉后2h、3 h(复苏状态)大鼠的CST自发放电频率显著增加,波幅明显减小[(640.13±126.01)μV vs(200.44±19.53)μV、(144.49±22.52)μV],差异有统计学意义(P＜0.05).ISI值从较为集中变化为较为分散. 结论 麻醉复苏过程中大鼠的CST自发放电在放电频率、波幅、ISI等神经电信号的特征方面存在明显差异.     

Unmyelinated fibers in the pyramidal tract of the rat: a new view

An electron microscopical morphometric analysis has been carried out at the medullary level of the pyramidal tract of the rat in order to quantify both myelinated and unmyelinated fibers: it was found that unmyelinated fibers outnumber myelinated ones substantially (133,000 ± 18,000 versus 91,000 ± 11,000, respectively). The unmyelinated fibers range from 0.05 to 1 μm in a monomodal distribution (mean 0.16 μm). For myelinated axons also a monomodal distribution was observed (ranges: axon 0.10–4 μm, mean 0.80 μm; myelin sheath 0.25–5 μm, mean 1.19 μm).