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Odor Coding in Piriform Cortex

梨状皮层的气味编码

基本信息

批准号：
10734194
负责人：
Kevin Franks
金额：
$ 56.99万
依托单位：
DUKE UNIVERSITY
依托单位国家：
美国
项目类别：
财政年份：
2016
资助国家：
美国
起止时间：
2016-06-01 至 2028-05-31
项目状态：
未结题

项目摘要

The perception and recognition of odors allow animals to identify food sources, avoid predators, and find potential mates as they navigate their surroundings. These behaviors require at least three essential compu-tations: (1) the ability to discriminate between similar odors while simultaneously allowing generalization for odor recognition; (2) acquiring and retrieving odor associations; and (3) assigning value to salient odors to guide appropriate behaviors. Although the piriform (PCx) cortex is thought to be the locus for odor perception and odor learning and memory, whether or how the PCx performs these essential computations remains unknown. Our long-term goal is to mechanistically understand how odor information is processed to drive appropriate behaviors. The objective of this proposal is to identify where and how the PCx performs these three essential computations. The PCx has two major types of principal cells, semilunar cells (SLs) and py- ramidal cells (PYRs), which have distinct morphologies, synaptic connectivity, and projection targets. Our central hypothesis is that different PCx cell types play distinct and specific roles in these essential com-putations. To this end, we propose the following three aims. Aim 1: To reveal the neural substrates of discrimination and generalization in PCx. We will train mice to discriminate between two odorants and then record from identified SLs and PYRs as the mice are pre-sented with a morphing series of binary mixtures of the two. Our preliminary data support our hypothesis that SLs discriminate and PYRs generalize responses to similar odors. Aim 2: To reveal the neural substrates for acquiring and retrieving odor memories. We do not under-stand how odor memories are formed, or where and how are they stored and retrieved? We will use viral tools with different transgenic mouse lines to selectively suppress activity in SLs or PYRs just before the acquisition or before the retrieval phases of an odor memory task. We hypothesize that SLs are required for the acquisi- tion but not the retrieval of odor memories, while PYRs are required for both acquisition and retrieval. Aim 3: To determine how odor identity and value information emerge in the medial prefrontal cortex (mPFC). mPFC receives direct projections from PCx and encodes odor value. We hypothesize that odor information is directly routed from PCx to mPFC by one specific subset of PYRs (Tbr1 neurons); that Tbr1 neurons encode odor identify but not odor value; and that the conjunction of odor identity and odorvalue in mPFC occurs through strengthening connections between PCx Tbr1 neurons and their postsynaptic partners in mPFC. This study will reveal the distinct roles that different subsets of PCx neurons and circuits play in processing odor information to guide flexible and appropriate behaviors, and can provide more general insight into how information is transformed within and across canonical circuits throughout the brain.

对气味的感知和识别使动物能够识别食物来源，避免捕食者，并找到潜在的配偶，因为他们浏览他们的周围环境。这些行为至少需要三个基本的计算：（1）区分相似气味的能力，同时允许泛化，气味识别;（2）获取和检索气味关联;以及（3）为显著气味赋值，引导适当的行为。尽管梨状皮质被认为是气味感知的场所，以及气味学习和记忆，PCx是否或如何执行这些基本计算仍然存在。未知我们的长期目标是机械地了解气味信息是如何处理的，适当的行为。本提案的目的是确定PCx在何处以及如何执行这些三个基本计算PCx有两种主要类型的主细胞，半月形细胞（SL）和py- 分支细胞（PYR），其具有不同的形态、突触连接和投射靶点。我们中心假设是不同的PCx细胞类型在这些基本计算中发挥不同的和特定的作用。为此，我们提出以下三个目标。目的1：揭示PCx辨别和概括的神经机制。我们会训练老鼠以区分两种气味剂，然后当向小鼠提供一系列两种气味剂的二元混合物时，记录所识别的SL和PYR。我们的初步数据支持我们的假设， SL的歧视和PYR概括反应相似的气味。目的二：揭示气味记忆获得和提取的神经机制。我们不了解气味记忆是如何形成的，或者它们是在哪里以及如何存储和检索的？我们将使用病毒工具用不同的转基因小鼠品系在获得前选择性抑制SL或PYR的活性或者在气味记忆任务的提取阶段之前。我们假设SL是获得所需的- 气味记忆的获取和提取都需要PYR，而气味记忆的提取和提取都需要PYR。目的3：确定气味身份和价值信息是如何在内侧前额叶皮层出现的（mPFC）。mPFC接收来自PCx的直接投射并编码气味值。我们假设气味信息通过PYR（Tbr 1神经元）的一个特定子集从PCx直接路由到mPFC; Tbr 1神经元编码气味识别而不编码气味值，气味识别与气味值的结合可能是一种新的气味识别机制。 mPFC中通过加强PCx Tbr 1神经元及其突触后之间的连接而发生 MPFC的合作伙伴。这项研究将揭示不同的PCx神经元和回路的子集在加工中发挥的不同作用气味信息，以指导灵活和适当的行为，并可以提供更一般的洞察如何信息在整个大脑的规范回路内和跨规范回路进行转换。

项目成果

期刊论文数量（8）

专著数量（0）

科研奖励数量（0）

会议论文数量（0）

专利数量（0）

Odor coding in piriform cortex: mechanistic insights into distributed coding.

DOI：
10.1016/j.conb.2020.03.001
发表时间：
2020-10
期刊：
Current opinion in neurobiology
影响因子：
5.7
作者：
Blazing RM;Franks KM
通讯作者：
Franks KM

Parallel processing by distinct classes of principal neurons in the olfactory cortex.

DOI：
10.7554/elife.73668
发表时间：
2021-12-16
期刊：
eLife
影响因子：
7.7
作者：
Nagappan S;Franks KM
通讯作者：
Franks KM

Chronic loss of inhibition in piriform cortex following brief, daily optogenetic stimulation.

DOI：
10.1016/j.celrep.2021.109001
发表时间：
2021-04-20
期刊：
Cell reports
影响因子：
8.8
作者：
Ryu B;Nagappan S;Santos-Valencia F;Lee P;Rodriguez E;Lackie M;Takatoh J;Franks KM
通讯作者：
Franks KM

Electrophysiological Recordings from Identified Cell Types in the Olfactory Cortex of Awake Mice.

清醒小鼠嗅觉皮层中已识别细胞类型的电生理记录。