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重新配置为 产生不同的输出。一个需要解决的主要问题是， 这种重新配置是如何发生的？多项研究表明， 外源性神经调节输入可引起电路重新配置 改变神经元特性和突触强度的物质。或者， 电路可以自我重新配置，根据它们的 自己的活动模式。最近的证据表明，这种情况可能是由于 神经网络固有的神经调节作用。这个 这项研究的目的是研究“内在神经调节”的作用。 在电路重新配置和节奏模式生成中。 在海洋软体动物Tritonia中有一个神经元网络，即 能够从调节戒断反射的回路自我改变的 以产生有节奏的逃生游泳行为。中的两种单元格 该网络对电路中的其他细胞产生神经调制效应 (一种细胞类型是5-羟色胺能的，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，则它们被激活 在每一集游泳节目中。因此，电路似乎是自我调节的。 每次它被激活时，以及在其执行 行为。 该项目的具体目标是：i)识别蜂窝和 三叉神经环的内源性神经调节的突触位点； 二)确定5-羟色胺在其中一些的产生中的作用 神经调节作用；以及Ill)研究内在的作用 神经调制在电路重构和加法模式生成中的作用 对现有电路的计算机模拟进行调制。 研究这个小型神经网络将为我们提供更多关于 内在神经调节机制，并将增加我们的 对这种鲜为人知的形式的功能意义的理解 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.