家兔小脑中央核向脊髓直接投射的研究

本实验将WGA-HRP分別注入家兔脊髓一侧的颈、胸、腰等不同节段,逆行追踪小脑中央各核向脊髓的直接投射。结果表明,小脑中央核的标记神经元恒定地见于颈段(C_1～C_4)注入例动物,而未见于下颈段(C_6～C_8)和胸腰段注入例动物。标记神经元仅出现于注入侧对侧的小脑顶核及间位核的尾侧部。研究结果提示,家兔小脑顶核及间位核的尾侧部,有向颈髓的直接越边投射。本结果为进一步探讨小脑对躯体运动的调节功能提供形态学基础。     

家兔楔外核和后索核的小脑投射—HRP法研究

用逆行轴突运输辣根过氧化物酶法研究了家兔楔外核和后索核的小脑投射。在注射HRP液于小脑前蚓和顶核之后,在其楔外核和后索核中见到标记细胞,楔外核中的标记细胞数多于后索核中的。后索核中的标记细胞主要在其吻侧部。在注射于后蚓和左旁正中小叶之后,只分别在双侧或同侧楔外核中见到标记细胞。本文提供了家兔后索核发纤维到小脑的证据。     

家兔Edinger—Westphal核至脊髓的投射——HRP法研究

用家兔15只,分别将不同量的30％HRP或5％WGA-HRP注入颈髓、胸髓或腰髓内,观察Edinger—Westphal核(E—W核)向脊髓的投射以及此种投射有无定位分布关系。同时,观察了家兔E—W核的正常形态学。家兔的E—W核为中线结构,位于动眼神经核头侧及背内侧,包括头侧的前正中核(AM核)及尾侧的固有E—W核两部。AM核最头端分成左右两部。两核均由中、小型梭形细胞构成,但AM核之细胞较狭长。AM核及固有E—W核的细胞向脊髓颈、胸及腰段有广泛的投射,各段投射细胞在核内分布弥散,无明显定位。但AM核头端分成左右两半处的细胞主要投射至腰髓。     

大鼠腰髓膨大部脊髓小脑束神经元向小脑皮质的投射

将大鼠胸髓在Ｔ＿（１０）—Ｔ＿（１１）间的左侧半横切断，然后将ＷＧＡ—ＨＲＰ注入腰髓膨大部，观察标记终末（Ｌａｂｅｌｅｄｔｅｒｍｉｎａｌｓ，ＬＴ）在小脑皮质的分布。结果表明：当ＷＧＡ—ＨＲＰ注入腰髓膨大左侧时，ＬＴ主要分布在前叶（约占全部ＬＴ的７５％），其中Ⅲ和Ⅳ小叶最多（３８％和２６％），后叶较少（２５％）。ＬＴ集中分布在小叶尖端，中间部较少，基部更少。注入同侧的小脑皮质ＬＴ较多（８２％），对侧较少（１８％）。在Ⅲ和Ⅳ小叶的横切面上ＬＴ可以划分为距中线１．０～１．５ｍｍ，１．５～２．０ｍｍ，２．０～２．５ｍｍ３个集中分布区。当ＷＧＡ—ＨＲＰ注入腰髓膨大右侧时，ＬＴ主要分布在前叶（７８％），其中Ⅲ和Ⅳ小叶最多（２７％和２４％），后叶较少（２２％）。ＬＴ主要分布在小叶的中间部，小叶尖端较少，基部更少。注入部同侧小脑皮质ＬＴ较多（９０％），对侧较少（１０％）。在Ⅲ和Ⅳ小叶的横切面上它们可以区分为距中线０．５～１．０ｍｍ，１．０～１．５ｍｍ，１．５～２．０ｍｍ３个集中分布区。     

家兔脊髓向延髓外侧网状核投射的体部定位——HRP顺行法研究

本实验用HRP顺行传递法研究了家兔脊髓向外侧网状核的纤维投射,结果是: 1.颈、胸和腰髓都有少数的神经元发出纤维投射于双侧的三叉神经下亚核。 2.颈、胸和腰髓至外侧网状核的投射都是双侧性的,但颈髓以同测投射为主,腰髓以对侧投射为主,胸髓至双侧的投射无明显差别。 3.脊髓神经元主要投射于外侧网状核的尾侧半,有体部定位关系。颈髓投射于大细胞亚核的外侧3/5及相邻的部分小细胞亚核;胸髓投射于大细胞亚核的内侧3/5及相邻接的部分小细胞亚核;腰髓投射于小细胞亚核及相邻接的一部分大细胞亚核,相互间有部分重叠。     

家兔前庭核与脊髓的联系——HRP法研究

将HRP注入家兔颈、胸或腰髓的一侧灰质内,追踪前庭四核内的逆行标记细胞和顺行标记终支。发现同侧外侧核内标记细胞数量甚多,且具有体部定位规律。内侧核及降核的尾段标记细胞也较多,内侧核者甚为密集,它们投射到双侧脊髓的颈、胸、腰段,对侧多于同侧,无体部定位关系。降核的头段及在此平面的内侧核内也有一定数量的标记细胞,也投射到颈、胸、腰髓,同侧为主,无体部定位关系。上核内只有极少量标记细胞,主要投射到对侧颈髓。顺行标记终支于降核、内侧核的见端小范围内及外侧核的尾端背面较为恒定,颈、腰注射例在降核和内侧核的尾端尤为密集。     

大鼠腰髓脊髓小脑束神经元向小脑中央核的投射—BDA顺行追踪研究

本实验采用 BDA顺行追踪法研究了大鼠腰髓脊髓小脑束向小脑中央核的投射。结果发现 :(1)大鼠腰髓脊髓小脑束神经元 (Clarke氏柱、第 层神经元和脊髓边缘细胞 )可向两侧小脑中央核投射 ,并以注射部位同侧的投射为主 ;(2 )大鼠腰髓脊髓小脑束向小脑中央核的投射主要分布于内侧核及间位核 ,并存在一定的体部定位关系。同时 ,首次发现有向外侧核的投射     

运用HRP逆行追踪法对家兔脊髓小脑束起始细胞的研究

本文在11只家兔小脑内,进行单侧或双侧辣根过氧化物酶注射,以研究脊髓各部标记神经元的分布。同时,为确定胸髓以下这些神经元轴突是否在脊髓内交叉上行,其中4只家兔在注射前,还作了下胸髓的一侧半断。标记的脊髓小脑束起始细胞在脊髓中分布甚广。位于颈髓的有:1.中央颈核(C_(1～4));2.Ⅵ层内侧部细胞(C_2～T_1);3.Ⅶ层中央部细胞(C_(4～8));4.后角Ⅳ～V层细胞(C_(5～8))。胸髓以下的标记细胞可分两大类:1.具有不交叉上行轴突的细胞为:(1)背核(T_(2～L_4));(2)后角Ⅳ～Ⅵ层细胞(T_2～L_6)。2.具有交叉越边上行轴突的细胞则包括:(1)脊髓前角边缘细胞(L_(3～6));(2)Ⅶ层内侧群细胞(L_5以下骶尾髓);(3)后角V层细胞(骶尾髓);(4)前角Ⅶ～Ⅷ层细胞(骶尾髓)。家兔脊髓小脑束起始细胞的分布和轴突投射特点,与猫相类似。这对进一步用家兔研究脊髓小脑系统的解剖学和生理学打下一定基础。     

家兔中脑网状结构内巨细胞至脊髓的投射——HRP法及WGA HRP法研究

在家兔中脑网状结构中,我们看到一些散在的巨细胞,位于红核头侧半背外方的中脑被盖内,形态和大小与延髓网状核的巨细胞相似。将HRP或WGA-HRP注入家兔颈、胸或腰段脊髓后,这些散在的巨细胞超过半数被标记。并以红核头端平面出现最多。在标记细胞附近还出现了标记终末,说明中脑网状结构与脊髓之间存在着往返联系。     

家兔皮质脊髓束投射神经元的分布

将辣根过氧化物酶（ＨＲＰ）分别注入家兔脊髓单侧颈、胸、腰等不同节段，以显示皮质脊髓束投射神经元的分布。结果表明，大脑皮质的ＨＲＰ标记神经元仅见于颈段注入例，而胸段和腰段注入例未见到皮质标记神经元。标记的皮质脊髓束投射神经元主要分布于注入侧对侧的额叶无颗粒型皮质和顶叶颗粒型皮质，并呈现为３个分隔的标记细胞密集区，分别位于额叶皮质吻侧端的内侧部、邻近前囟的额顶叶皮质、顶叶皮质的外侧部。标记神经元呈柱状     

Spinal projections to the cerebellar nuclei in the cat

Summary Projections from the spinal gray matter to the cerebellar nuclei in the cat have been studied using Nauta's silver technique. Following unilateral section of the ventrolateral cord at the cervical level, heavy degeneration is seen in the nucleus medialis on both sides. Scanty degeneration is present bilaterally in the nucleus interpositus. The degeneration is most intense on the contralateral side. Scanty degeneration is also present bilaterally in subnucleus medialis parvicellularis (SMP) (Flood and Jansen, 1961). No degeneration is seen in nucleus lateralis. Following unilateral section of the dorsolateral cord at the cervical level, scanty degeneration is present bilaterally in nucleus medialis and nucleus interpositus anterior. The degeneration is more pronounced ipsilaterally and is also seen in SMP on both sides. No degeneration is present in nucleus lateralis. Fibers from the ventral and dorsal spinocerebellar tracts (VSCT and DSCT) terminate bilaterally in nuclei medialis and interpositus, with the VSCT as the most important connection.     

Arrangement of neurons in the medullary reticular formation and raphe nuclei projecting to thoracic, lumbar and sacral segments of the spinal cord in the cat

Summary The distribution of neurons in the medullary reticular formation and raphe nuclei projecting to thoracic, lumbar and sacral spinal segments was studied, using the technique of retrograde transport of horseradish peroxidase (HRP), alone or in combination with nuclear yellow (NY). Retrogradely labeled cells were observed in the lateral tegmental field (FTL), paramedian reticular nucleus, magnocellular reticular nucleus (Mc), in the gigantocellular nucleus (Gc), lateral reticular nucleus (LR), lateral paragigantocellular nucleus (PGL), rostral ventrolateral medullary reticular formation (RVR), as well as in the medullary raphe nuclei following the injection of the tracer substance(s) into various levels of the spinal cord. The FTL, the ventral portion of the paramedian reticular nucleus (PRv), Mc, LR, PGL and the raphe nuclei were found to project to thoracic, lumbar and sacral spinal segments. This projection was bilateral; the contralaterally projecting fibers crossed the midline at or near their termination site. The dorsal portion of the paramedian reticular nucleus (PRd), Gc and the RVR projected mainly to thoracic segments. This projection was unilateral. Experiments in which the HRP-injection was combined with lesion of the spinal cord showed that some descending raphe-spinal axons coursed presumably alongside the central canal. Experiments with two tracer substances suggested that some reticulo and raphe-spinal neurons had axon collaterals terminating both in thoracic and sacral spinal segments.Abbreviations CC Central Canal - FTL Lateral Tegmental Field - Gc Gigantocellular Nucleus - IO Inferior Olive - LR Lateral Reticular Nucleus - Mc Magnocellular Reticular Nucleus - Nc Cunetae Nucleus - Ng Gracile Nucleus - P Pyramidal Tract - PGL Lateral Paragigantocellular Nucleus - PRd Paramedian Reticular Nucleus,dorsal portion - PRv Paramedian Reticular Nucleus, ventral portion - RB Restiform Body - Ro Nucleus Raphe Obscurus - Rm Nucleus Raphe Magnus - Rpa Nucleus Raphe Pallidus - RVR Rostral Ventrolateral Medullary Reticular Formation - TSp5 Tractus Spinalis Nervi Trigemini - V4 Fourth Ventricle - 12N Hypoglossal Nerve - A B C D E and F correspond to levels Fr 16.0 Fr 14.7 Fr 12.7 Fr 11.6 Fr 10.0 and Fr 9.2 posterior to the frontal zero     

丹参对脊髓损伤后伤区血流量及血液流变学指标的影响

目的 :比较应用丹参对兔脊髓损伤 (SCI)后伤区血流量及血液流变学指标的影响 ,探讨丹参对脊髓损伤的保护机制。方法 :5 8只成年日本大耳白兔 ,随机分成四组 ,A组 10只 ,作为正常组 ;B、C、D组各 16只 ,分别作对照组、地塞米松 (Dex)治疗组和丹参治疗组。比较脊髓损伤前后及应用Dex、丹参治疗后伤区血流量 (SCBF)及血液流变学指标的变化。结果 :脊髓损伤后 ,SCBF下降 ,血液粘度(ηb)、纤维蛋白原 (Fib)、细胞聚集指数 (RAI)增高。Dex对脊髓SCBF和血液流变学指标异常的改善不明显 ,而使用丹参治疗后 ,脊髓SCBF增高 ,血液流变学指标明显改善。结论 :丹参对脊髓损伤具有保护作用 ,且疗效较Dex明显 ,为临床治疗提供依据。     

Connections of Purkinje cell axons of lobule X with vestibulospinal neurons projecting to the cervical cord in the rat

Connections of Purkinje cell axons of lobule X (nodulus vermis) with vestibulospinal neurons have been demonstrated in the rat, by anterograde labeling of axons with biotinylated dextran (BD) injected into sublobule Xa and by retrograde labeling of neurons with cholera toxin subunit B (CTB) injected into cervical segments. Labeled terminals of Purkinje cell axons were numerous in the superior vestibular nucleus, the parvocellular (MVpc) and the caudal part (MVc) of the medial vestibular nucleus (MV), and group y. A limited number of labeled terminals were seen in the caudal part of the descending vestibular nucleus (DV). Occasional labeled terminals were seen in the lateral part of the lateral vestibular nucleus (LV) whereas few labeled terminals were seen in the magnocellular part of the MV (MVmc). Vestibulospinal neurons labeled from the C2 and C3 segments were seen bilaterally in the MVmc, MVpc, MVc, and DV, and ipsilaterally in the LV. CTB-labeled vestibulospinal neurons in contact with BD-labeled terminals of Purkinje cell axons were identified in the lateral part of the MVpc, near the border between the MVpc and MVmc, or close to the dorsal acoustic stria, and in the middle part of the MVc at its rostral level. The present study suggests that Purkinje cells of lobule X regulate the output of cervical-projecting vestibulospinal neurons in the MVpc and MVc.     

Patterns of maturation of somatotopical distribution of corticospinal neurons in postnatal rats

Summary To better comprehend somatotopic development of the corticospinal projection system, wheat germ agglutinin conjugated to horseradish peroxidase (WGA-HRP) was injected into cervical or lumbar enlargement of the spinal cord of postnatal rats. The cervical projecting neurons appeared first in the middle of the lateral surface of the posterior frontal and anterior parietal cortex on the second postnatal day (postnatal day one, P1). By P3, labeled neurons were distributed in the rostral two-thirds of the cortex, with concentrations both on the same cortex as in P1 and on the dorsomedial part of the frontal cortex. Size of the labeled area was gradually reduced between P3 and P12 to attain an adult organization: three discrete clusters of labeled neurons were isolated in the dorsomedial part of the frontal cortex, the middle of the lateral surface of the posterior frontal and anterior parietal cortex, and in the temporal cortex. The lumbar projecting neurons first appeared in the dorsomedial part of the parietal cortex, on P4. Size of the lumbar projecting area increased by P6 and decreased by P12 to attain the pattern seen in adult animals.Our findings suggest that 1) potential pioneer fibers reaching the cervical enlargement originate from the middle of the lateral surface of the posterior frontal and anterior parietal cortex, and those reaching the lumbar enlargement, from the dorsomedial part of the parietal cortex, and 2) transiently projecting areas consist of less densely distributed neurons compared to the areas destined to become the corticospinal projecting area in adult.     

Anatomical evidence for brainstem circuits mediating feeding motor programs in the leopard frog, Rana pipiens

Using injections of small molecular weight fluorescein dextran amines, combined with activity-dependent uptake of sulforhodamine 101 (SR101), brainstem circuits presumed to be involved in feeding motor output were investigated. As has been shown previously in other studies, projections to the cerebellar nuclei were identified from the cerebellar cortex, the trigeminal motor nucleus, and the vestibular nuclei. Results presented here suggest an additional pathway from the hypoglossal motor nuclei to the cerebellar nucleus as well as an afferent projection from the peripheral hypoglossal nerve to the Purkinje cell layer of the cerebellar cortex. Injections in the cerebellar cortex combined with retrograde labeling of the peripheral hypoglossal nerve demonstrate anatomical convergence at the level of the medial reticular formation. This suggests a possible integrative region for afferent feedback from the hypoglossal nerve and information through the Purkinje cell layer of the cerebellar cortex. The activity-dependent uptake of SR101 additionally suggests a reciprocal, polysynaptic pathway between this same area of the medial reticular formation and the trigeminal motor nuclei. The trigeminal motor neurons innervate the m adductor mandibulae, the primary mouth-closing muscle. The SR101 uptake clearly labeled the ventrolateral hypoglossal nuclei, the medial reticular formation, and the Purkinje cell layer of the cerebellar cortex. Unlike retrograde labeling of the peripheral hypoglossal nerve, stimulating the hypoglossal nerve while SR101 was bath-applied labeled trigeminal motor neurons. This, combined with the dextran labeling, suggests a reciprocal connection between the trigeminal motor nuclei and the cerebellar nuclei, as well as the medulla. Taken together, these data are important for understanding the neurophysiological pathways used to coordinate the proper timing of an extremely rapid, goal-directed movement and may prove useful for elucidating some of the first principles of sensorimotor integration. Electronic Publication     

The cerebellar projection from the reticular formation of the brain stem in the rabbit

Summary By retrograde transport of horseradish peroxidase the reticulocerebellar projections were examined in twenty-six rabbits.After injections in the cerebellum retrogradely labeled neurons were more numerous in the caudal reticular formation (ventral and gigantocellular reticular nuclei) than in its rostral part (caudal and oral pontine reticular nuclei). The labeled cells were of all sizes, large, medium-sized and small. Giant cells were labeled only after injections in the posterior lobe vermis.After injections in the anterior lobe, the posterior vermis, the fastigial nucleus and the flocculus, retrogradely labeled neurons were found bilaterally in the ventral reticular nucleus, the gigantocellular reticular nucleus and the caudal pontine reticular nucleus. Some cases with posterior vermal and fastigial injections in addition showed labeled neurons bilaterally in the oral pontine reticular nucleus. There were no major side differences. The cases with injections in the anterior part of the paramedian lobule gave rise to only a few labeled cells in the gigantocellular reticular nucleus.Negative findings were consistently made in the mesencephalic reticular formation.     

Cerebellar cortical and nuclear afferents from the Edinger-Westphal nucleus in the cat

Summary The cerebellar projection from the Edinger-Westphal nucleus was studied in the cat by means of retrograde transport of the wheat germ agglutinin-horseradish peroxidase complex. The present findings give evidence that the flocculus is the main terminal area. However, small tracer implants and injections into various parts of the cerebellar nuclei and cortex revealed projections also to the fastigial and interposed nuclei and to most parts of the anterior and posterior lobe cortices. The projecting neurons are small and located bilaterally throughout the Edinger-Westphal nucleus. No topical differences between the projections to different parts of the cerebellum were found.