Neuronal connection of the cortex and reconstruction of the visual space

The distributions of retrograde labeled cells in fields 17 and 18 and the fields 17/18 transitional zone were studied in both hemispheres of cats after microiontophoretic administration of horseradish peroxidase into individual cortical columns in fields 17, 18, 19, and 21a. The clustered organization of the internal connections of the cortical fields, the asymmetrical locations of labeled callosal cells relative to the injected columns, and the defined distribution of labeled cells in layers A of the lateral geniculate body suggested that eye-specific neuronal connections support binding of the visual hemifields separately for each eye. Application of marker to columns in fields 19 or 21a demonstrated disparate inputs from fields 17 and 18 and the fields 17/18 transitional zone. It is suggested that these connections may support the extraction of loci and stereoscopic boundaries located in the central sectors of the visual space.Translated from Rossiiskii Fiziologicheskii Zhurnal imeni I. M. Sechenova, Vol. 89, No. 10, pp. 1281–1290, October, 2003.     

A combined 2-deoxyglucose and neurophysiological study of primate somatosensory cortex

The metabolic activity pattern produced in the primary somatosensory cortex (SI) of primates by repetitive delivery of a tactile stimulus is distinctly patchy. The functional significance of these patches, however, remains obscure. This investigation sought to determine the correlation between neural and metabolic activity produced by tactile stimuli and to evaluate the relationship, if any, between the neural activity and metabolic patches evoked by similar stimuli. Experiments were undertaken in which extracellular microelectrode recordings were carried out in animals that subsequently underwent a 2-deoxyglucose (2DG) study. Three types of relations were identified. First, the receptive fields (RF) and modality properties of neurons sampled in locations at which patches of metabolic label were found matched the "place" and "modal" properties of the stimulus used to produce 2DG labeling. Second, in cortical locations where the RF and modality properties of the sampled neurons differed from either the place or modal properties of the stimulus used to evoke the 2DG label, no above-background increases in metabolic labeling were found. Finally, in some cortical locations at which the receptive field and modality properties of the neurons matched those of the 2-deoxyglucose mapping stimulus, no above-background increases in metabolic labeling were found. This outcome leads us to suggest that moment-to-moment changes in neural responsivity, which might remain undetected by conventional receptive field mapping methods, contribute to the patchy pattern of metabolic activity visualized by the 2-deoxyglucose method.     

Vertebral level of the ending of the spinal cord and its relationship to the length of the vertebral column in Northern Turkish neonates

Summary Racial and sex differences in the level of ending of the spinal cord of the adult have been reported. It is lower in Africans and in females. Since such differences may affect even fetuses and newborns we aimed to study in Northern Turkish neonates. The study was made on 40 full-term newborn still-births (23 male, 17 female). In all cases, the length of the vertebral column, the length of the spinal cord and the body weight were measured and the vertebral level of ending of the spinal cord was noted. It was found that the termination of the spinal cord varied from the first lumbar to the second sacral vertebra, with a mean level between L2 and L3. In female neonates, it was observed that the spinal cord ended at a slightly lower level (0.2 vertebra) than in males. Our findings approximately agreed with those of Barson [2] who studied neonates in England and of Jit and Charnalia [5] in North India. However, we found that the spinal cord ended one and half vertebrae lower in Northern Turkish neonates than in South African and South Indian subjects. The correlations between body-weight and length of the spinal cord, weight and length of the vertebral column, length of the spinal cord and length of vertebral column, length of the vertebral column and level of ending of the cord were statistically highly significant for males, females and both sexes together (p<0.001). The longer the vertebral column, the higher the termination of the spinal cord.

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Niveau vertébral de la terminaison de la moelle épinière et sa relation avec la longueur de la colonne vertébrale chez le nouveau-né en Turquie du Nord

Résumé Selon la race et le sexe, les différences de niveau de la terminaison de la moelle épinière ont été rapportées chez l'adulte. Elle est plus basse chez les Africains et chez les femmes. Dès lors il se peut qu'il existe déjà des différences raciales et selon le sexe, chez le foetus et le nouveau-né. Nous nous proposons d'étudier une population de nouveau-nés du Nord de la Turquie. Cette étude est faite à partir de 40 nouveau-nés à terme, décèdes (23 garçons et 17 filles). Chez tous ces nouveau-nés, la longueur de la colonne vertébrale, la longueur de la moelle épinière et le poids ont été mesurés. Le niveau vertébral de la terminaison de la moelle épinière variait entre la première vertèbre lombaire et la deuxième vertèbre sacrée. Le niveau moyen de cette terminaison était situé entre L2 et L3. Chez les filles nouveau-nés, il était observé que la moelle épinière se terminait légèrement plus bas (0,2 vertèbre) que chez les garçons nouveaunés. Nos observations rejoignent celles de Barson [2] qui étudia des nouveaunés d'Angleterre et celles de Jit et Charnalia [5] qui étudièrent des nouveau-nés du Nord de l'Inde. Cependant, nous avons trouvé que la moelle épinière se terminait une vertèbre et demie plus bas chez les nouveau-nés de la Turquie du Nord que chez les nouveau-nés d'Afrique du Sud et d'Inde du Sud. La corrélation entre le poids des spécimens et la longueur de la moelle épinière; le poids et la longueur de la colonne vertébrale, la longueur de la moelle épinière et la longueur de la colonne vertébrale, la longueur de la colonne vertébrale et le niveau vertébral de la terminaison de la moelle épinière parmi les garçons, les filles, et dans les deux sexes, étaient statistiquement très significatifs (p<0.001). Plus la colonne vertébrale était longue, plus haute était située la terminaison de la moelle épinière.

     

脊柱有关角度的观测及机能意义

对30具男性成人干燥椎骨的体根角、横突间夹角、弓根间夹角及上关节面与横截面冠状面成角进行了测算,并观察了上关节面的方向、形态及横突与上关节突、椎弓根间的相互位置关系。通过综合分析,讨论了不同节段有关角度的差异与重力线,脊柱曲度大小,方向的关系以及在活动节段中的机能意义。     

煤快速加氢热解焦油组成的分析

采用溶剂萃取－化学处理－柱层析相结合的预处理分离程序、色－质联用和色－红联用结合色谱保留值的定性方法,分析研究了内蒙东胜煤快速加氢热解焦油的化学成分和结构,推测鉴定出２００多种化合物,并对具有代表性的１９种多环芳烃进行了定量分析,讨论了快速加氢热解焦油化学成分的结构特征。     

柱切换HPLC法测定腹水中左旋氧氟沙星的含量

目的：应用柱切换ＨＰＬＣ技术直接测定腹水中左旋氧氟沙得含量。方法：采用磷酸二氢钾缓冲溶液（ＰＨ２．２）－０．０５ｍｏｌ／Ｌ四丁溴化化铵（１００：４）为预处理流动相,经μＢｏｎｄａｐａｋ Ｃ１８柱预处理后,切换到Ｉｒｒｅｇｕｌａｒ＿ＨＣ１８分析柱,以甲醇－磷权二氢钾缓冲溶液（ＰＨ２．２）－０．０５ｍｏｌ／Ｌ四丁基溴化铵（３０：７０：４）为分析流动相进行分离测定,紫外线皮长为２９４ｎｍ。结果：左旋氧氟     

NMDA受体与NOS在大鼠脊髓中间外侧柱的定位和生后发育

目的 探讨N-甲基-天冬氨酸受体（NMDAR1和NMDAR2A/B亚基）、一氧化氮合酶（NOS）及还原型辅酶Ⅱ硫辛酰胺脱氢酶（NADPH-d）活性在大鼠脊髓中间外侧柱（IML）的定位与生后发育特征。方法 在甲醛固定的脊髓切片上,进行ABC法免疫染色和NADPH-d组织化学反应与半定量分析。结果 MMDAR1,NMDAR2A/B,NOS I和NADPH-d反应产物丰富地分布于IML,主要定位于神经元胞体、树突和轴突样纤维终末。在生后早期发育中它们具有明显的动态变化,生后7d(P7）有微弱或中等的表达,随后逐渐上调,P21或P28达到高峰,然后保持于此水平于成体动物。结论 NMDA受体-NO通路可能是脊髓交感节前神经元一条重要的细胞内信号途径,并参与神经元生后发育成熟的调控过程。     

Release of [3H]5-hydroxytryptamine from the intermediate area of rat thoracic spinal cord is modulated by presynaptic autoreceptors

Serotonin (5-HT) nerve terminals innervate sympathetic preganglionic neurons of the intermediolateral cell column (IML); however, neither the depolarization-induced release of 5-HT nor the presence of presynaptic modulatory autoreceptors have been directly studied in this system. We used in vitro superfusion of the microdissected intermediate area (including the intermediolateral cell column, intercalated nucleus, and central autonomic nucleus) of the rat thoracic spinal cord to measure basal and stimulated release of preloaded [³H]5-HT. Elevated K⁺ evoked a concentration- and Ca²⁺ dependent release of [³H]5-HT. Exogenous 5-HT and the 5-HT_1B agonist, CGS-12066B, both decreased the K⁺-stimulated release of [³H]5-HT. A 5-HT_1B antagonist (methiothepin) blocked the 5-HT- and the CGS-12066B-induced inhibition of K⁺-evoked release of [³H]5-HT. A 5-HT_1A antagonist (NAN-190) did not alter the inhibitory actions of exogenous 5-HT. Moreover, a 5-HT_1A agonist (8-OH-DPAT), a 5-HT_2A/2C agonist [(+/-)-DOI hydrochloride], and a 5-HT₃ agonist (2-methyl-5-HT) did not alter the K⁺ evoked release of [³H]5-HT. These data demonstrate that 5-HT is released from the intermediate area of the rat thoracic spinal cord. The 5-HT receptor subtype involved in the inhibition of the evoked release of [³H]5-HT is of the 5-HT_1B subtype. These findings may help clarify the complex role of 5-HT in spinal regulation of the sympathetic nervous system. © 1994 Wiley-Liss, Inc

1 This article is US Government work and, as such, is in the public domain in the United States of America.

     

Pax-1 in the development of the cervico-occipital transitional zone

The Pax-1 gene has been found to play an important role in the development of the vertebral column. The cervico-occipital transitional zone is a specialized region of the vertebral column, and malformations of this region have frequently been described in humans. The exact embryonic border between head and trunk is a matter of controversy. In order to determine a possible role of Pax-1 in the development of the cervico-occipital transitional zone we studied the expression of this gene in a series of quail embryos and murine fetuses with in situ hybridization and immunohistochemistry. Pax-1 is expressed in all somites of the embryo, including the first five occipital ones. During embryonic days 3–5 the gene is down-regulated in the caudal direction within the first five somites, whereas more caudally Pax-1 is strongly expressed in the cells of the perinotochordal tube. In 5-day-old quail embryos, the cartilaginous anlage of the basioccipital bone has developed and there is no more expression of Pax-1 in this region. The fusion of the dens axis with the body of the axis also coincides with switching off of the Pax-1 gene. More caudally, the gene is continuously expressed in the intervertebral discs of murine embryos and therefore seems to be important for the process of resegmentation. Quail embryos do not possess permanent intervertebral discs. Hyper- or hyposegmentation defects may be explained by an over- or under-expression of Pax-1 during development. We also reinvestigated the border between the head and trunk in chick embryos by performing homotopical grafting experiments of the 5^th somite between chick and quail embryos. Grafted quail cells formed mainly the caudal end of the basioccipital bone. They were also located in the cranial half of the ventral atlantic arch, and only a few cells were found in the tip of the dens axis.