NEUROBIOLOGY OF GUSTATORY NEURONS IN SOLITARY NUCLEUS

本研究旨在了解形态和合生体 C 初级味觉中继核的组织及其在 味道 味觉系统对人类的健康和生存起着至关重要的作用 生物体。 它负责评估潜在的食品物质 接受或拒绝，也是一个重要的传入成分， 既有影响饮食选择的复杂习得行为， 对食物摄取至关重要的口面反射。 喙部的三分之一 孤束核是味觉感受区 传入信息 这也是味觉系统 发散成一个上升的组成部分，潜在的知觉和享乐 味觉的各个方面，以及一个脑干成分，有助于协调 摄食反射 虽然它们是不同行为功能的基础， 这两个子系统的相对感觉 功能协调发展的 生成这种细分的NST组织的属性 n 也是未知的。 长期研究将使用形态学和电生理学 分析Rostrol NST中的输出神经元，以便开始深入研究 NST组织。 这些细胞要么向吻侧突出，要么向上突出， G 子系统，或尾侧，进入脑干通路。 形态学实验 计划，其中树枝状形态和输出分布 神经元，通过荧光示踪剂的逆行运输鉴定， 通过细胞内注射荧光黄揭示了这一点。 电 传入外周神经的刺激将用于比较神经元 根据传入输入的来源，相对贡献 的来源和响应特性。 时间复合脉冲串 刺激也将用于研究二阶效应， 由神经元的内在属性产生或通过局部 突触回路，调节这些细胞的峰后反应。 类似的记录实验将在体外培养中进行。 的吻侧NST，以建立输出神经元之间的对应关系， 在体内和体外发挥作用。 大脑切片将建立一个 其中吻侧NST中神经元细胞类型之间的相互关系可以 使用细胞内形态学和电生理学 技术. 这些研究涉及几种新的和 味觉生理学的动力技术。 这些实验将根据1）内含子定义输出神经元的类别 C NST处理，2）传入输入的访问，和3）形态特征。 它们将为未来的实验提供必要的信息， 在NST神经元的识别的子集中的味觉编码，并且用于定义 NST神经元间突触相互作用研究进展 工作 这一研究将有助于了解组织的 脑干和味觉系统的高级功能，以及基本感觉 整个神经系统的系统过程。

This research is directed toward understanding the morphological and synapt c organization of the primary gustatory relay nuclues and how it functions in taste. The gustatory system plays a vital role in the health and survival of the organism. It is responsible for evaluating potential food substance for acceptance or rejection, and is also an important afferent component in both complex learned behaviors influencing diet selection and coordinated orofacial reflexes essential for food ingestion. The rostral one-third of the nucleus of the solitary tract is the recipient zone for gustatory afferent information. It is also the point from which the gustatory system diverges into an ascending component, underlying the perceptual and hedonic aspects of taste, and a brainstem component contributing to coordination of ingestive reflexes. Although they underlie different behavioral functions, these two subsystems are not well understood as to their relative sensory functions. The properties of NST organization that generate this subdivisi n are also unknown. The prolonged studies will use morphological and electrophysiological analysis of output neurons in rostrol NST to begin an in-depth investigatio of NST organization. These cells project either rostrally, into an ascendi g subsystem, or caudally, into a brainstem pathway. Morphological experiment are planned, in which dendritic morphology and distribution of output neurons, identified by retrograde transport of fluorescent tracers, is revealed by intracellular injection of Lucifer Yellow. Electrical stimulation of afferent peripheral nerves will be used to compare neuronal responses in terms of the sources of afferent input, relative contributions of sources, and response characteristics. Temporally complex pulse train stimulation will also be used to investigate second order effects, either resulting from the neurons' intrinsic properties or produced via local synaptic circuitry, that modulate postspike responsiveness in these cells. Similar recording experiments will be carried out in an in vitro preparatio of the rostral NST, to establish the correspondence between output neuron function in vivo and in vitro. The brain slice will establish a preparatio in which interrelationships between neuronal cell types in rostral NST can be investigated using intracellular morphological and electrophysiological techniques. These studies involve the first application of several new and power techniques to gustatory physiology. These experiments will define classes of output neurons based on 1) intrins c NST processing, 2) access to afferent input, and 3) morphological features. They will provide information essential for future experiments comparing taste coding in identified subsets of NST neurons, and for defining hypotheses about synaptic interactions among NST neurons for future in vitr work. This research will contribute to understanding of the organization o brainstem and higher functions of the gustatory system, and basic sensory system processes throughout the nervous system.