Oscillations and Resonance in Basal Ganglia Circuits

长期以来，基底节功能和功能障碍的模型一直基于描绘通过核团的电活动流的电路图。这些模型指导了基底节神经退行性疾病的治疗方法的发展，并继续对新治疗方法的设计和改进有用。功能模型的有效性及其对新疗法设计的预测价值与每个核团中电路的准确信息密切相关。我们对基底节核团神经元之间的解剖连接的了解很好，并且正在迅速改进，但我们对电路对电活动流动的影响的了解还处于初级阶段。本文分析了基底神经节主要输入核团(纹状体)和主要输出核团(黑质)内回路的功能特点。这些实验使用正弦输入和一定频率范围内的正弦组合来表征局部电路对神经元反应的影响。这些输入与神经元和突触的已知共振特性相结合，它们将揭示电路相互作用产生的其他共振。在一些实验中，输入是通过细胞内或光遗传传递给电路中的一些或所有细胞类型，而在另一些实验中，周期性输入信号通过连续控制上游神经元的放电而通过突触传递给电路。这些实验将揭示放大或抑制基底节节律活动的电路机制，包括作为帕金森病主要病理生理成分的β振荡，以及在DBS期间产生的治疗性周期信号。

Models of basal ganglia function and dysfunction have long been based on a circuit diagram sketching the flow of electrical activity through the nuclei. These models have guided the development of treatments for neurodegenerative diseases of the basal ganglia, and continue to be useful for design and refinement of new treatments. The validity of the functional models and their predictive value for design of new treatments is tightly linked to accurate information on the circuitry in each of the nuclei. Our knowledge of the anatomical connectivity among neurons in basal ganglia nuclei is good and improving rapidly, but our understanding of circuit effect on the flow of electrical activity is in its infancy. In this proposal, the functional characteristics of circuits in the main input nucleus of the basal ganglia (the striatum) and that in the main output nucleus (the substantia nigra) are analyzed. The experiments use sinusoidal inputs and combinations of sinusoids over a range of frequencies to characterize the effects of local circuits on neuronal responses. These inputs engage the known resonance properties of the neurons and synapses, and they will reveal other resonances that arise from circuit interactions. In some experiments, the input is intracellularly or optogenetically delivered to some or all cell-types in the circuit, whereas in others the periodic input signal to the circuit is delivered synaptically by continuously controlling firing of upstream neurons. These experiments will reveal the circuit mechanisms that amplify or suppress rhythmic activity in the basal ganglia, including both the beta oscillations that are a principal pathophysiological component of Parkinson's disease, and the therapeutic periodic signal generated during DBS.