Dynamics of odor coding and processing by neural circuits in the olfactory bulb

项目总结 理解感觉的一个基本步骤是理解大脑中的神经回路 将感觉神经元活动的模式转化为对外部世界的强健和有效的表示。 感觉是一个主动的过程，在这个过程中，感觉信息的检测和初始编码是动态的 受采样行为的影响。了解中枢回路如何处理大脑中的感觉信息 主动采样的背景对于理解行为动物感觉的神经基础至关重要。 这个项目的目标是了解哺乳动物嗅球中的神经回路是如何转变的。 在体内和在主动气味采样或嗅探的背景下的感觉输入。 首先，我们将研究二尖瓣兴奋性驱动不同模式的电路级决定因素。 以及簇生细胞，重点关注感觉输入和肾小球回路在产生这种反应中的各自作用 多样性。其次，我们将定义刺激物本身是否以及如何具有特征--特别是气味化学和 强度-与对MT细胞的兴奋性驱动的动力学有关，以及这些动力学是如何形成的 通过嗅探行为。最后，我们将询问兴奋性输入的动力学和肾小球模式如何影响 嗅球的输入-输出转换。 建议的实验实现了几种创新的方法来解剖电路功能 完整的嗅球；包括使用第二代谷氨酸光学记者直接成像 对二尖瓣/簇状细胞的兴奋性信号，具有高时间分辨率，谷氨酸和 用于同时监测突触前输入和二尖瓣/簇状细胞活动读数的钙 肾小球，并使用识别出的具有良好特征的反应光谱的肾小球来设计强大的 模型预测的检验。 该项目的总体影响将是推动对两国关系的机械性理解 气味采样的动态和由此导致的嗅球神经活动的动态之间的关系。 这些发现将为最终理解神经动力学和主动 气味感知中的采样作用。

PROJECT SUMMARY A fundamental step in understanding sensation is understanding how neural circuits in the brain transform patterns of sensory neuron activity into robust and efficient representations of the external world. Sensation is an active process in which the detection and initial encoding of sensory information is dynamically modulated by sampling behavior. Understanding how central circuits process sensory information in the context of active sampling is critical for understanding the neural basis of sensation in the behaving animal. The goals of this project are to understand how neural circuits in the mammalian olfactory bulb transform sensory inputs in vivo and in the context of active odor sampling, or sniffing. First, we will examine circuit-level determinants of the diverse patterns of excitatory drive onto mitral and tufted cells, focusing on the respective roles of sensory inputs and glomerular circuits in generating this diversity. Second, we will define if and how stimulus features themselves – in particular, odorant chemistry and intensity – relate to the dynamics of excitatory drive onto MT cells, as well as how these dynamics are shaped by sniffing behavior. Finally, we will ask how dynamics and glomerular patterns of excitatory input impact the input-output transformation of the olfactory bulb. The proposed experiments implement several innovative approaches to dissecting circuit function in the intact olfactory bulb; these include using second-generation optical reporters of glutamate to directly image excitatory signaling onto mitral/tufted cells with high temporal resolution, dual-color imaging of glutamate and calcium to simultaneously monitor presynaptic inputs and readouts of mitral/tufted cell activity from the same glomerulus, and the use of identified glomeruli with well-characterized response spectra to design powerful tests of model predictions. The overall impact of the project will be to advance a mechanistic understanding of the relationship between the dynamics of odor sampling and the resulting dynamics of neural activity in the olfactory bulb. These findings will pave the way for ultimately understanding the role that neural dynamics and active sampling play in odor perception.