CRCNS: The balance of excitation and inhibition in sensory cortex

CRCNS：感觉皮层兴奋和抑制的平衡

基本信息

批准号：
8837164
负责人：
Nicholas J Priebe
金额：
$ 19.31万
依托单位：
UNIVERSITY OF TEXAS AT AUSTIN
依托单位国家：
美国
项目类别：
财政年份：
2014
资助国家：
美国
起止时间：
2014-09-30 至 2017-08-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/8837164
关键词：
Accounting Address Affect Afferent Neurons American Animals Biology Brain Cells Collaborations Complex Computer Simulation Country Data Dependence Educational process of instructing Engineering Environment Equilibrium Europe European Exhibits Felis catus France General Population Generations Goals Home environment International Light Link Location Maps Measures Microscopy Modeling Mus Nature Neurons Pattern Physics Postdoctoral Fellow Primates Property Recurrence Research Rodent Scheme Science Scientist Sensory Process Side Site Specificity Students Synapses System Testing Thalamic structure Training United States V1 neuron Visit Visual Visual Cortex Work base computer studies critical period equilibration disorder experience mouse model network models orientation selectivity preference receptive field research study response sensory cortex theories two-photon visual information visual stimulus web site

项目摘要

DESCRIPTION (provided by applicant): Visual cortex (V1) is the site at which dramatic transformations in neuronal receptive field properties - and thus the representation of the visual world - occur. One of the major transformations is the emergence of orientation selectivity. The functional organization of orientation selectivity in V1, however, takes different forms across species. In primates and carnivores it is topographically organized across cortex but in rodents no apparent organization is observed, yet rodents still exhibit orientation selectivity. Models tha describe the emergence of orientation selectivity have relied on the functional organization found in primates to guide connectivity between neurons that share selectivity. Two different hypotheses have been proposed to explain the emergence of orientation selectivity without functional organization in rodent V1. In one hypothesis, a specific synaptic connectivity between neurons with shared orientation preference may nonetheless exist without topographic organization of cortex. Alternatively, a computational study has now demonstrated that orientation selectivity may arise from non-specific network connectivity, with the constraint that the excitatory and inhibitory inputs are balanced ("balanced network model"). These two hypotheses are not mutually exclusive, and evidence for both hypotheses currently exists, but the degree to which each of these hypotheses reflects the actual connectivity underlying orientation selectivity in rodent V1 is unclear. The goal of our proposal is to address the relativ contributions of the balanced network and specific cortical connectivity to the generation of V1 orientation selectivity using experimental and computational studies. The proposed research is divided into three Specific Aims that will be carried out collaboratively and will integrate theory and experiment. Aim 1: What is the nature of the LGN input into layer 4 of V1 and how does layer 4 transform this input? In species with an orientation map, the LGN neurons afferent inputs are precisely arranged. Is this also true for species without an orientation map, and how does subcortical selectivity impact cortical selectivity? Can we explain the mechanism for orientation selectivity using a balanced network? Aim 2: Is the cortical connectivity specific? If V1 operates in the balanced state, strong orientation selectivity will arise in layer 2/3, whether or not the connectivity is feature dependet. We will measure the orientation dependence of input correlations and integrate any specific connectivity into a balanced model. Aim 3: How does disturbing the balanced state affect the cortical response? Our hypothesis is that the V1 operates in balanced excitation and inhibition regime. Perturbing this balance will be investigated theoretically and experimentally. Despite decades of study as the prime example of sensory processing, how V1 transforms incoming visual information is not well understood. It is not clear for example, whether feature specific connectivity is required to perform its function. I species with an orientation map, feature specific connectivity is not easily distinguished from connectivity that is solely dependent on anatomical distance because the anatomical and functional maps are linked. The lack of an anatomical organization for orientation selectivity in rodent V1 therefore presents us with an opportunity to study circuitry in a system in which the functional selectivities of neurons are independent of their location within the cortical network. Our proposal represents an integrative collaboration between theoreticians and experimentalists that will create an environment for students and postdoctoral fellows from different background to work side-by-side, gaining access to distinct expertise and perspectives. The collaboration represents a major effort for scientists to work in partnership between France and the US. This partnership will provide students from both France and the US the opportunity to participate in science outside of their home country. The proposed computational and experimental lab work is ideal for the training of students and postdoctoral fellows with backgrounds in physics, engineering or biology. It will be an excellent opportunity for theorists t see and participate in experiments, and for experimentalists to explore a theoretical perspective.

描述（由申请人提供）：视觉皮层（V1）是神经元感受野特性（以及视觉世界的表征）发生戏剧性转变的部位。主要转变之一是方向选择性的出现。然而，V1 中方向选择性的功能组织在不同物种中采取不同的形式。在灵长类动物和食肉动物中，它在皮质上按地形组织，但在啮齿类动物中没有观察到明显的组织，但啮齿类动物仍然表现出方向选择性。描述方向选择性出现的模型依赖于灵长类动物中发现的功能组织来指导共享选择性的神经元之间的连接。人们提出了两种不同的假设来解释啮齿动物 V1 中没有功能组织的方向选择性的出现。在一种假设中，具有共享方向偏好的神经元之间的特定突触连接可能在没有皮层地形组织的情况下仍然存在。或者，一项计算研究现已证明，方向选择性可能源自非特定网络连接，并限制兴奋性和抑制性输入平衡（“平衡网络模型”）。这两个假设并不相互排斥，并且目前存在这两个假设的证据，但是这些假设中的每一个在多大程度上反映了啮齿类动物 V1 中方向选择性的实际连接性尚不清楚。我们提案的目标是通过实验和计算研究来解决平衡网络和特定皮质连接对 V1 方向选择性生成的相对贡献。拟议的研究分为三个具体目标，这些目标将协同进行并整合理论和实验。目标 1：V1 第 4 层的 LGN 输入的性质是什么？第 4 层如何转换该输入？在具有方向图的物种中，LGN 神经元的传入输入是精确排列的。对于没有方向图的物种来说也是如此吗？皮质下选择性如何影响皮质选择性？我们可以解释使用平衡网络的方向选择性机制吗？目标 2：皮质连接是否特定？如果 V1 在平衡状态下运行，无论连接性是否依赖于特征，第 2/3 层都会出现强方向选择性。我们将测量输入相关性的方向依赖性，并将任何特定的连接性集成到平衡模型中。目标 3：扰乱平衡状态如何影响皮质反应？我们的假设是 V1 在平衡的兴奋和抑制状态下运行。扰乱这种平衡将在理论上和实验上进行研究。尽管作为感觉处理的主要例子进行了数十年的研究，但 V1 如何转换传入的视觉信息尚不清楚。例如，尚不清楚是否需要特定功能的连接来执行其功能。在具有方向图的情况下，特征特定连接性不容易与仅依赖于解剖距离的连接性区分开，因为解剖学和功能图是链接的。因此，啮齿类动物 V1 缺乏方向选择性的解剖组织，为我们提供了研究系统中电路的机会，在该系统中，神经元的功能选择性与其在皮质网络中的位置无关。我们的建议代表了理论家和实验家之间的综合合作，将为来自不同背景的学生和博士后研究员创造一个并肩工作的环境，获得不同的专业知识和观点。此次合作代表了法国和美国科学家之间合作的一项重大努力。这种伙伴关系将为法国和美国的学生提供在本国之外参与科学活动的机会。拟议的计算和实验实验室工作非常适合培训具有物理、工程或生物学背景的学生和博士后研究员。这将是理论家观看和参与实验、实验家探索理论视角的绝佳机会。