Encoding information that coordinates distributed neural microcircuits

神经科学的一个主要目标是了解神经回路的动力学。在大多数情况下，对内在神经特性和电路的突触组织的忽视限制了我们理解电路功能或治疗由其故障引起的神经系统疾病的能力。递质和激素的调节可以极大地改变这些电路中神经元和突触的特性，但电路性能的一些特征却奇怪地保持不变。这个项目利用了对小龙虾中枢神经系统(CNS)中协调肢体运动的电路的突触组织的新发现。这个协调电路连接了四对模块化的局部电路，它们分布在中枢神经系统的不同部位，控制着单独的肢体，并在运动过程中处于活跃状态。这些本地电路的周期性电机输出是同步的，但在相邻电路之间存在稳定的相位差。这项研究的目标是用细胞术语理解和解释协调这些分布式电路所需的信息编码。电生理学实验和计算分析将被用来研究和模拟电路中关键的协调神经元对信息的编码。如何在神经调节的情况下保持稳定的相位差是一个深层次的问题。例如，这个系统的胆碱能调制改变了它的马达输出的周期和强度，但不影响相邻电路之间的相位差。电生理学和药理学实验将被用来分析胆碱能调制如何调整编码，以便在周期变化时相位保持不变。这项研究将产生洞察力和分析方法，可以应用于脑干和脊髓的类似系统，以及大脑中有节奏的神经回路。学生参与者将参与项目的各个方面。这一结果也将直接适用于灵活和自适应机器人设备的开发。

A major goal of neuroscience is to understand the dynamics of neural circuits. In most cases, ignorance of intrinsic neural properties and the synaptic organization of circuits limit our ability to understand a circuit's function or to cure disorders of the nervous system caused by its malfunction. Modulation by transmitters and hormones can change the properties of neurons and synapses in these circuits dramatically, but leave some features of the circuit's performance strangely unmodified. This project exploits new discoveries of the synaptic organization of a circuit in the crayfish central nervous system (CNS) that coordinates limb movements during locomotion. This coordinating circuit links four pairs of modular local circuits distributed in different parts of the CNS that control individual limbs and are active during locomotion. Periodic motor output from these local circuits is synchronized, but occurs with a stable difference in phase between neighboring circuits. The goal of this research is to understand and explain in cellular terms the encoding of information needed to coordinate these distributed circuits. Electrophysiological experiments and computational analyses will be used to study and model encoding of information by the circuit's key coordinating neurons. How stable phase differences are maintained in the face of neuromodulation is a deep problem. For example, cholinergic modulation of this system changes the period and strength of its motor output, but does not affect the phase differences between neighboring circuits. Electrophysiological and pharmacological experiments will be used to analyze how cholinergic modulation tunes encoding so that phase remains constant when period changes. This research will generate insights and analytical methods that can be applied to similar systems in the brain stem and spinal cord, and to rhythmic neural circuits in the brain. Student participants will be involved in all aspects of the project. The results will also be directly applicable to the development of flexible and adaptive robotic devices.