Ethologically relevant short term memory in the olfactory bulb

摘要 短期记忆是认知的重要组成部分。在这里，我们将从行为学上调查一个 引导航行行为的短时记忆的相关形式：气味浓度的交叉记忆 闻一闻。这种嗅觉间记忆已被证明在研究自由活动的动物时指导嗅觉搜索， 但这些实验中的刺激很难控制和测量。为了更好地控制注意力 波动，我们已经开发了一种系统，用于呈现快速改变浓度的刺激- 修复了老鼠。使用这个系统，我们已经揭示了嗅球神经元具有嗅觉间记忆， 其反应依赖于之前嗅觉中的刺激。在这里，我们将调查持续时间， 使用双光子电生理学的嗅觉间记忆表示的分辨率和细胞基础 成像和高分辨率行为分析。 从固定头部的实验中推断出的相互嗅觉记忆代码是否会推广到自然行为？至 回答这个问题，我们已经建立了一种不受限制的嗅觉导航实验。老鼠学会了这项任务 快速，并通过跟踪气味浓度变化来解决这一任务。我们发现老鼠会执行一种 与嗅觉循环精确同步的三维动作曲目。重要的是 只有当动物能够在环境中自然移动时，这些行为动态才会被揭示出来。 这些运动是如何影响嗅觉记忆表征的？我们的行为任务给了我们一个 史无前例的机会测试从受控简单刺激中获得的感受野模型 自然主义的刺激和运动的背景。对于给定的鼠标，我们将首先在Head-Fixed和 确定在该条件下的内部嗅探内存编码。然后，我们将在同一只小鼠身上测试相同的神经元 在我们的行为任务中。头部固定编码规则能多好地预测自由运动中的活动 情况如何？通过定义行为学上相关气味动力学的神经表示，我们的工作将 促进对大脑如何实现对改变的输入的短期记忆的总体理解 通过时间，这是引导成功行为的关键。

ABSTRACT Short-term memory is an essential component of cognition. Here, we will investigate an ethologically relevant form of short-term memory that guides navigation behavior: memory of odor concentration across sniffs. This intersniff memory has been shown to guide olfactory search in studies of freely moving animals, but the stimuli in these experiments are hard to control and measure. To better control concentration fluctuation, we have developed a system for presenting stimuli that rapidly change concentration to head- fixed mice. Using this system, we have revealed that neurons of the olfactory bulb have intersniff memory, with responses that depend on stimulation in previous sniffs. Here, we will investigate the duration, resolution, and cellular basis of intersniff memory representations using electrophysiology, 2-photon imaging, and high-resolution behavioral analysis. Will intersniff memory codes inferred from head-fixed experiments generalize to natural behavior? To answer this question, we have established an unrestrained olfactory navigation assay. Mice learn this task rapidly, and solve the task by following odor concentration changes. We have found that mice execute a repertoire of three-dimensional movements that are precisely synchronized to the sniff cycle. Importantly, these behavioral dynamics are only revealed when an animal is able to move naturally in the environment. How do these movements impact intersniff memory representations? Our behavioral task gives us an unprecedented opportunity to test receptive field models derived from controlled simple stimulation in the context of naturalistic stimulation and movement. For a given mouse, we will first record in head-fixed and determine intersniff memory coding in that condition. We will then test the same neurons in the same mouse in our behavioral task. How well can the head-fixed coding rules predict activity in the freely-moving condition? By defining the neural representation of ethologically relevant odor dynamics, our work will advance a general understanding of how the brain implements short-term memory for input that changes through time, which is essential to guide successful behavior.