Attentional modulation of olfaction in mice

 描述（由申请人提供）：根据个体的内部状态，相同的感官刺激可能在不同时间被不同地感知。注意过程是众所周知的，它允许个体过滤掉不相关的刺激，并专注于与生存相关的环境方面。造成这种感知差异的潜在神经机制是什么？它们如何影响行为？特别是，注意力对气味处理的影响的神经机制在很大程度上是未知的，代表了我们对嗅觉系统功能的理解的一个主要空白。然而，人类功能成像研究发现了证据表明，气味导向的注意力调节嗅觉皮层的气味表征-这一发现对感觉系统功能产生了重要影响。此外，胆碱能对刺激加工的影响被假设为提供了一种机制，即注意增强刺激表征和胆碱能纤维通过嗅觉皮层的直接输入。 水平对角带（HDB）提供了一个解剖框架，由此注意力依赖性胆碱能传递可以调节这些结构中的气味编码。在拟议的研究中，我已经制定了两个具体的目标，这将测试的整体假设，即气味导向的注意控制气味的信号-噪声比在两个突出领域的嗅觉皮层，接收密集的嗅球输入，嗅结节（OT）和梨状皮质（PCX）。这两个目标都将涉及记录小鼠的神经活动，这些小鼠参与了一项强大的操作性任务，旨在系统地操纵气味导向的注意力。在目标1中，我将确定注意力对嗅觉皮层神经系统中气味编码的影响。在目标2中，我将采用光遗传学直接测试HDB对气味编码的影响，以及嗅觉皮层神经系统中注意力介导的气味编码。总的来说，这项提议的结果将揭示基本原则，即注意力以一种可能最终影响感知和气味引导行为的方式塑造气味信息的皮层编码。

 DESCRIPTION (provided by applicant): Depending on the internal state of an individual, the same sensory stimulus may be perceived differently at different times. Attentional processes are especially well known to allow an individual to filter out irrelevant stimuli and focus on aspects f the environment that are relevant for survival. What are the underlying neural mechanisms that contribute to this difference in perception and how do they influence behavior? In particular, the neural mechanisms underlying the influences of attention on odor processing are largely unknown and represent a major void in our understanding of olfactory system function. Human functional imaging research has however uncovered evidence that odor-directed attention modulates the representation of odors in the olfactory cortex - a finding which yields important implications for sensory system function. In addition, cholinergic influences on stimulus processing are hypothesized to provide a mechanism whereby attention enhances stimulus representation and the direct input of cholinergic fibers into the olfactory cortex by means of the horizontal diagonal band (HDB) provides an anatomical framework whereby attention-dependent cholinergic transmission may modulate odor coding in these structures. In the proposed research, I have developed two specific aims which will test the overall hypothesis that odor-directed attention controls odor signal-to-noise ratios in two prominent areas of the olfactory cortex which receive dense olfactory bulb input, the olfactory tubercle (OT) and the piriform cortex (PCX). Both Aims will involve recording neural activity from mice engaged in a powerful operant task designed to systematically manipulate odor-directed attention. In Aim 1, I will determine the impact of attention on the coding of odors among olfactory cortex neural ensembles. In Aim 2, I will employ optogenetics to directly test the influences of the HDB on odor coding and also attentionally-mediated odor coding among olfactory cortex neural ensembles. Overall, the results of this proposal will reveal fundamental principles whereby attention shapes the cortical coding of odor information in a manner whereby it may ultimately influence perception and odor-guided behaviors.