GRADED SYNAPTIC TRANSMISSION IN LOCAL NEURAL CIRCUITS

拟议研究的目的是增加我们对 局部回路神经元使用的突触机制，特别是， 突触分级传递在局部放电中的作用 电路神经元。眼前的目标是理解 分级、棘波诱发和神经调节性突触的作用 传输到一个小型神经网络的功能， 龙虾和螃蟹的口胃神经节。在这之前的几年里 Grant，生理特性和一些潜在的机制 对突触传递的分级进行了描述。在下一个授权期内， 重点将放在神经元结构和突触的解剖学方面 组织，以及相关的电压生理测量 在神经元内部和连接的细胞对之间传播。这些方法 使用范围包括：细胞内记录和染料注入、电压 钳夹、免疫染色和共聚焦显微镜。 口胃神经元具有串联突触结构，延伸 树突和分级突触属性似乎是理想的 专为区域计算而设计。然而，到目前为止，还没有证据表明 他们按地区计算，目前还不清楚他们是如何避免这样做的。 神经调节剂可以功能性地重新连接大脑中的突触连接。 口胃神经节，但我们不知道它们在哪里活动。因此， 关于这些神经元的突触组织及其相关信息 如果我们想要理解电子紧张性的性质 每个神经元对这个局部神经功能的贡献 巡回赛。提供这些信息是这项提案的目标。 这些神经元在结构上类似于较难接近的丘脑神经元。 在人类和口胃运动网络中作为人类的模型 有节奏的运动功能，包括走路和咀嚼。通过增加我们的 了解这个模型系统是如何工作的，我们可能会获得一些线索 常见的运动病理基础以及系统如何重新调整 以恢复正常功能。

The objective of the proposed research is to increase our understanding of the synaptic mechanisms used by local circuit neurons and, in particular, to study the function of graded synaptic transmission in spiking, local circuit neurons. The immediate objective is to understand the contributions of graded, spike-evoked, and neuromodulator synaptic transmission to the functioning of a small neural network, the stomatogastric ganglion of lobsters and crabs. In earlier years of this grant, the physiological properties and some of the underlying mechanisms of graded synaptic transmission were described. In the next grant period, the focus will be on anatomical aspects of neuron structure and synaptic organization, and on correlated physiological measurements of voltage spread both within a neuron and between connected cell pairs. The methods to be used include: intracellular recording and dye injection, voltage clamp, immunostaining, and confocal microscopy. Stomatogastric neurons have the serial synaptic structure, extended dendrites, and graded synaptic properties that appear to be ideally designed for regional computation. However, so far there is no evidence that they regionally compute and it is not clear how they avoid doing so. Neuromodulators can functionally rewire the synaptic connections in the stomatogastric ganglion, but we don't known where they act. Thus, information on the synaptic organization of these neurons and on their electrotonic properties is essential if we are to understand the contribution made by each neuron to the functioning of this local neural circuit. Providing that information is the objective of this proposal. These neurons are structurally similar to less accessible thalamic neurons in humans and the stomatogastric motor network serves as a model for human rhythmic motor functions, including walking and chewing. By increasing our knowledge of how this model system works, we may gain clues to what underlies common motor pathologies and to how the system can be readjusted to restore normal function.