SYNAPTIC ORGANIZATION IN SPINAL CORD AND THALAMUS

该研究项目涉及神经元和 哺乳动物躯体感觉丘脑的突触组织。 大脑的这个区域接收来自 提升体感系统并传输此信息 到躯体感觉皮层。 虽然丘脑经常 被称为“中继核”，很明显， 在这个主要的间脑结构中进行信息处理。 丘脑的神经回路正在被检查， 几种实验技术：1） 小麦胚芽凝集素-凝集素结合的微量注射 将辣根过氧化物酶（WGA-HRP）制成选定区域 已知的投射到躯体感觉的神经轴 丘脑 利用一种新开发的方法， 从投射到丘脑的各个部位产生的， 通过电子显微镜和它们的精确分布显示 在丘脑神经元表面的分布。 （二） 细胞内标记生理学特征的 丘脑体感神经元结合在某些情况下， 轴突运输方法可以揭示突触群体 与这些神经元接触的神经元， 特定的途径， 躯体感觉神经元 这些神经元的突触输入是 然后用三维计算机重建 程序. 3)免疫细胞化学方法用于描述 这些神经元和突触结构含有假定的 神经递质，如γ-氨基丁酸（GABA）， 血清素乙酰胆碱或去甲肾上腺素 据信 其中一些传递器改变了丘脑的放电模式 神经元，从而改变信息的传输，通过 丘脑4）单克隆抗体已经提出了对 从躯体感觉丘脑获得的突触体组分， 随后对其活性进行筛选。 我们得到了六个 抗体（超过3,000种）似乎选择性地 标记躯体感觉丘脑中的特定元素。 这些抗体将被检查，以确定他们是否可以 用于识别轴突终末的某些类别， 丘脑，为了进一步扩大我们的分析能力， 丘脑回路 结合现代解剖学和生理学 在这项研究中使用的方法提供了一个强大的手段， 将神经元的结构和功能特性联系起来， 构成神经系统的主要成分， 各种躯体感觉机制，使动物和 人类检测和解释刺激所产生的皮肤和 身体的深层组织

This research program is concerned with the neuronal and synaptic organization of the mammalian somatosensory thalamus. This region of the brain receives afferent information from ascending somatosensory systems and transmits this information to the somatosensory cortex. Although the thalamus is frequently termed a "relay nucleus", it is evident that there is much complex information processing within this major diencephalic structure. The neuronal circuitry of the thalamus is being examined by several experimental techniques: 1) orthograde transport of wheat germ lectin - microinjections of lectin conjugated to horseradish peroxidase (WGA-HRP) are made into selected regions of the neuraxis which are known to project to the somatosensory thalamus. Utilizing a newly developed methodology, the synapses arising from various sites which project to the thalamus can be revealed by electron microscopy and their precise distribution over the surfaces of thalamic neurons determined. 2) Intracellular labeling of physiologically characterized somatosensory thalamic neurons combined in some cases with the axon transport methodology can reveal the synaptic populations which contact these neurons, as well as the projections of particular pathways upon physiologically-characterized somatosensory neurons. The synaptic input to these neurons is then mapped using a three-dimensional computer reconstruction program. 3) Immunocytochemical methods are used to describe those neuronal and synaptic structures which contain putative neural transmitters, such as gamma-aminobutyric acid (GABA), serotonin, acetylcholine or norepinephrine. It is believed that some of these transmitters change the firing patterns of thalamic neurons and thus alter the transmission of information through the thalamus 4) Monoclonal antibodies have been raised against synaptosome fractions obtained from somatosensory thalamus and subsequently screened for their activity. We have obtained six antibodies (out of more than 3,000) which appear to selectively label particular elements within the somatosensory thalamus. These antibodies will be examined to determine whether they can be used to identify certain classes of axon terminals within the thalamus, in order to further expand our abilities to analyze thalamic circuitry. The combined use of modern anatomical and physiological methods to be used in this study provide a powerful means to relate structural and functional properties of neurons which constitute a major element of the nervous system concerned with a variety of somatosensory mechanisms, which allow animals and humans to detect and interpret stimuli arising from cutaneous and deep tissues of the body.