INTRINSIC NEUROMODULATION OF A SMALL NEURONAL NETWORK

神经元网络通常是多功能的，也就是说， 具有解剖学上定义的突触连接的细胞可以被重新配置， 产生不同的输出。 需要解决的一个主要问题是， 这种重新配置是如何发生的？ 几项研究表明 外部神经调节输入可以引起电路重构 从而改变神经元的特性和突触的强度。 可选择地， 电路可以自我重新配置，重新安排自己的基础上， 自己的活动模式。 最近的证据表明，这可能是由于 神经网络内在神经元的神经调节作用。 的 本研究的目的是探讨“内在神经调节”在脑缺血中的作用。 在电路重构和节奏模式生成中。 在海洋软体动物Tritonia中有一个神经元网络， 能够从一个介导退缩反射的回路 到产生有节奏的逃避游泳行为。 两种细胞类型 该网络对回路中的其他细胞产生神经调节作用 (one细胞类型是肾上腺素能的，另一种是肽能的）。 因为这些细胞 是图案生成电路的组成部分，它们被激活， 每一次游泳都是如此。 因此，电路似乎在自我调节 每当它被激活时， 行为 该项目的具体目标是：I）识别细胞， Tritonia游泳回路中内在神经调节的突触位点; II）确定血清素在产生其中一些中的作用 神经调节作用;和III）研究内源性神经调节因子的作用。 电路重构中的神经调制和通过添加 调制到电路的现有计算机模拟。 研究这个小的神经网络将提供更多的见解， 内在神经调节机制，并将增加我们的 了解这种鲜为人知的形式的功能意义 神经系统的可塑性。

Neuronal networks are often multifunctional, that is, a single group of cells with anatomically defined synaptic connections can be reconfigured to produce different outputs. A major question that needs to be addressed is, how does this reconfiguration occur? Several studies have shown that circuit reconfiguration can be caused by extrinsic neuromodulatory inputs that alter neuronal properties and synaptic strengths. Alternatively, circuits can be self-reconfiguring, rearranging themselves based on their own activity pattern. Recent evidence suggests this may arise as a result of neuromodulatory actions of neurons intrinsic to the network. The purpose of this study is to examine the role of "intrinsic neuromodulation" in circuit reconfiguration and rhythmic pattern generation. There is a network of neurons in the marine mollusc Tritonia that is capable of changing itself from a circuit that mediates a withdrawal reflex to one that produces a rhythmic escape swim behavior. Two cell types in the network evoke neuromodulatory effects on other cells in the circuit (one cell type is serotonergic, the other peptidergic). Since these cells are integral parts of the pattern generating circuit, they are activated during every swim episode. Thus, the circuit appears to modulate itself every time that it is activated and throughout its performance of the behavior. The specific aims of this project are to I) identify the cellular and synaptic loci of intrinsic neuromodulation in the Tritonia swim circuit; II) determine the role of serotonin in producing some of these neuromodulatory effects; and Ill) study the role of intrinsic neuromodulation in circuit reconfiguration and pattern generation by adding the modulation to an existing computer simulation of the circuit. Studying this small neural network will provide more insights into the mechanisms of intrinsic neuromodulation, and will increase our understanding of the functional significance of this little-recognized form of nervous system plasticity.