CRCNS: Input/Output Characterization of the Antennal Lobe of the Drosophila

描述（由申请人提供）：本提案中描述的果蝇触角叶的I/O表征是通过两个关键的使能工具实现的：(I)投射神经元及其支配的肾小球的遗传鉴定，（ii）触角叶中气味信号处理的多输入/多输出（MIMO）建模。这两种工具最近都得到了作者的改进。在MIMO模型中，天线瓣及其功能用传递函数矩阵来描述。我们的目标是确定传输矩阵，并用相同的矩阵构建电路图，该矩阵能够预测天线瓣的时空I/O动态。MIMO模型是理论家和实验家之间的共同语言，并提供了一个框架，在这个框架内设计相关问题和设计实验来回答这些问题。例如，是否存在表现出较低复杂性的天线瓣的等效I/O特征？我们将通过(i)分析表达相同受体的嗅觉感觉神经元的任意子集对气味信息的表示，以及（ii）研究这些神经元之间的空间过滤方法作为气味信号处理的模型来研究这些特征。通过对果蝇嗅觉系统的基因操作，气味受体将在与指定肾小球相连的嗅觉感觉神经元中表达。通过沉默大部分剩余的肾原核，这些肾小球将有效地与触角叶的其余部分分离。这将为我们研究果蝇触角瓣的I/O特性提供一个“体内实验平台”。该平台将使我们首次能够从功能上表征支配同一肾小球的所有单个投射神经元。我们将研究它们是否具有生物物理等效以及它们是否携带等效的气味信息。我们还将把它们的映像描述为活动osn数量的函数。我们将提取单个肾小球和从触角叶其余部分分离的2个肾小球网络的转移基质。我们计划定量表征局部/投射神经元对同一肾小球内传递功能的抑制和反馈。我们还计划测量抑制和反馈对其他肾小球的影响。阐明嗅觉信号在触角叶中的加工过程可以揭示治疗嗅觉缺陷的方法。它还可以揭示其他感觉系统中神经编码的基本机制。

DESCRIPTION (provided by applicant): The I/O characterization of the Drosophila antennal lobe described in this proposal is made possible by 2 key enabling tools (i) the genetic identification of the projection neurons and the glomeruli they innervate and, (ii) multi-input/multi-output (MIMO) modeling of odor signal processing in the antennal lobe. Both tools have recently been advanced by the authors. The antennal lobe and its function are described in the MIMO model by a transfer function matrix. Our goal is to identify the transfer matrix and construct in silico a circuit diagram with the same matrix that is capable of predicting the spatio-temporal I/O dynamics of the antennal lobe. The MIMO model serves as a common language between theorists and experimentalists, and provides a framework within which to devise relevant questions and design experiments to answer those questions. For example, are there equivalent I/O characterizations of the antennal lobe that exhibit a lower complexity? We shall investigate such characterizations by (i) analyzing the representation of odor information by an arbitrary subset of olfactory sensory neurons expressing the same receptor, and (ii) studying spatial filtering methods among these neurons as a model of odor signal processing. Through genetic manipulation of the fly olfactory system, odor receptors will be expressed in olfactory sensory neurons connected to designated glomeruli. By silencing most of the remaining OSNs, these glomeruli will be effectively isolated from the rest of the antennal lobe. This will provide us with an ' in-vivo experimental platform' for investigating the I/O characteristics of the fly antennal lobe. The platform will enable us for the first time to functionally characterize all individual projection neurons innervating the same glomerulus. We shall investigate whether they are biophysically equivalent and whether they carry equivalent odor information. We will also characterize their image as a function of the number of active OSNs. We will extract the transfer matrix of a single glomerulus and of a network of 2 glomeruli isolated from the rest of the antennal lobe. We plan to quantitatively characterize the inhibition and feedback induced by the local/projection neurons on the transfer function within the same glomerulus. We also plan to measure what effect inhibition and feedback have on other glomeruli. Elucidation of odor signal processing in the antennal lobe could reveal methods of treatment of olfactory deficits. It could also reveal fundamental mechanisms of neural coding in other sensory systems.