SYNAPTIC INTEGRATION OF SENSORY AFFERENTS IN BRAINSTEM

脑干中感觉传入的突触整合

• 批准号: 2271828
• 负责人: MICHAEL ARIEL
• 金额: $ 13.09万
• 依托单位: SAINT LOUIS UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 1995
• 资助国家: 美国
• 起止时间: 1995-08-01 至 1998-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/2271828
• 关键词: Chelonia; brain electrical activity; brain mapping; brain stem; cell cell interaction; electrophysiology; membrane potentials; neural information processing; neurophysiology; organ culture; synapses; visual pathways; voltage /patch clamp; voltage gated channel

DESCRIPTION: A neuron processes information by integrating many synaptic inputs onto its dendritic tree, leading to its spike output. This project will investigate this neural processing by stimulating individual sensory afferents to a neuron in the vertebrate brainstem, using a sensory pathway which has the unique advantage of lacking topography. As a consequence, its afferent cell bodies are widely distributed in the sensory periphery. Specifically, intracellular recordings in the accessory optic system will be performed in a unique in vitro turtle brain preparation in which the eyes remain attached and the brain remains visually responsive. Neurons in the accessory optic system presumably receive their synaptic inputs from a distinct class of retinal cell, the direction sensitive ganglion cell. The interaction between the presynaptic terminals and a postsynaptic cell performs an essential conversion from local retinal directional information into a measure of global image motion, called retinal slip, that has a well defined role in vestibular and oculomotor reflexes. The turtle's accessory optic system is called the basal optic nucleus, a surface brainstem structure whose neurons are easy to locate in vitro. Postsynaptic events of cells in the basal optic nucleus are readily recorded with high fidelity in the whole cell configuration using patch pipettes. Visual and electrical stimulation of individual retinal afferents will be used to study the size and shape of unitary postsynaptic events as well as their direction tuning. Stimulating two afferents will determine how two synaptic potentials interact on the postsynaptic membrane. This interaction is complicated by the finding that synaptic responses to individual afferents are quite variable in amplitude and that the postsynaptic membrane has voltage sensitive channels that can be modulated by synaptic potentials. To further understand this interaction, we will also study the passive membrane properties of each cell, the voltage sensitive channels in its membrane, the ionic and pharmacological nature of the synaptic currents and the cell's morphology. This full analysis will ultimately clarify the neural transformations from the retinal synaptic input to the accessory optic system output. The results of these studies will provide insights into the functioning of neurons that encode the direction of visual field motion in order to maintain our balance and stabilize our gaze. Such visual processing will also provide an excellent model to understand general mechanisms of synaptic integration and the sensory processing of the brainstem.

描述：神经元通过整合许多突触来处理信息。 输入到它的树突树上，导致它的尖峰输出。这 该项目将通过刺激神经元来研究这种神经处理过程。 脊椎动物脑干中神经元的单个感觉传入， 利用一种感觉通路， 地形因此，它的传入细胞体广泛分布于 分布在感觉周围。具体来说，细胞内 辅助光学系统中的记录将在一个独特的 体外龟脑制备，其中眼睛保持附着， 大脑仍然保持视觉反应。副视神经的神经元 系统可能从不同类别接收突触输入 视网膜细胞是方向敏感的神经节细胞。的相互作用 在突触前末梢和突触后细胞之间， 从局部视网膜方向信息到 全局图像运动的测量，称为视网膜滑动，具有良好的 在前庭和眼反射中的作用。海龟的 辅助视系统称为基底视核，表面 脑干结构，其神经元易于在体外定位。 基底视核细胞的突触后事件很容易被发现。 使用贴片以高保真度记录整个细胞配置 移液管。个体视网膜的视觉和电刺激 传入将被用来研究的大小和形状的单一 突触后事件以及它们的方向调谐。刺激二 传入神经将决定两个突触电位如何在神经元上相互作用。 突触后膜这种相互作用因以下发现而变得复杂： 对单个传入神经的突触反应是相当可变的， 突触后膜具有电压敏感性 可以被突触电位调节的通道。进一步 了解这种相互作用，我们也将研究被动膜 每个细胞的特性，细胞膜上的电压敏感通道， 突触电流的离子和药理学性质， 细胞的形态。这一完整的分析将最终澄清 从视网膜突触输入到附件的神经转换 光学系统输出这些研究的结果将提供见解 编码视觉方向的神经元的功能 场运动，以保持我们的平衡和稳定我们的视线。 这样的视觉处理也将提供一个很好的模型来理解 突触整合和感觉处理的一般机制 脑干