CRCNS: The balance of excitation and inhibition in sensory cortex

CRCNS：感觉皮层兴奋和抑制的平衡

• 批准号: 8932697
• 负责人: Nicholas J Priebe
• 金额: $ 18.93万
• 依托单位: UNIVERSITY OF TEXAS AT AUSTIN
• 依托单位国家: 美国
• 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/8932697
• 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

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发生戏剧性变化的部位，因此是视觉世界的表征。其中一个主要的转变是方向选择性的出现。然而，V1中取向选择性的功能组织在不同物种之间采取不同的形式。在灵长类动物和食肉动物中，它是在皮层上组织起来的，但在啮齿动物中没有观察到明显的组织，但啮齿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在灵长类动物中发现的功能组织，以指导共享选择性的神经元之间的连接。有两种不同的假说被提出来解释方向选择性的出现没有功能组织在啮齿动物V1。在一种假设中，尽管如此，具有共同取向偏好的神经元之间的特定突触连接可能在没有皮层的地形组织的情况下存在。另一方面，一项计算研究表明，取向选择性可能来自非特异性网络连接，其约束条件是兴奋性和抑制性输入是平衡的（“平衡网络模型”）。这两种假设并不相互排斥，目前存在这两种假设的证据，但在何种程度上，这些假设反映了实际的连接基础的方向选择性在啮齿动物V1是不清楚的。我们的建议的目标是解决相对贡献的平衡网络和特定的皮层连接的V1方向选择性的产生，使用实验和计算研究。拟议的研究分为三个具体目标，将协同进行，并将整合理论 和实验 目标1：输入到V1第4层的LGN的性质是什么？第4层如何转换此输入？在具有方向图的物种中，LGN神经元的传入输入被精确地排列。对于没有方向图的物种，这是否也是正确的？皮层下的选择性如何影响皮层的选择性？我们能用平衡网络来解释取向选择性的机制吗？ 目的2：皮质连接是否特异？如果V1在平衡状态下工作，则在层2/3中将出现强的取向选择性，无论连接性是否是特征依赖的。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整合到一个平衡模型中。 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机制。扰动这种平衡将从理论和实验上进行研究。尽管几十年来，V1一直是感觉处理的主要例子，但人们对V1如何转换传入的视觉信息还没有很好的了解。例如，不清楚是否需要特征特定的连接来执行其功能。在具有方向图的物种中，特征特异性连接性不容易与仅依赖于解剖距离的连接性区分开，因为解剖图和功能图是链接的。因此，在啮齿动物V1中缺乏方向选择性的解剖组织为我们提供了一个研究系统中的电路的机会，在该系统中，神经元的功能选择性与它们在皮层网络中的位置无关。 我们的建议代表了理论家和实验家之间的综合合作，这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。这项合作是法国和美国科学家合作的一项重大努力。这一伙伴关系将为来自法国和美国的学生提供在本国以外参与科学的机会。拟议的计算和实验室工作是理想的学生和博士后研究员在物理，工程或生物学背景的培训。这将是一个很好的机会，理论家看和参与实验，并为实验家探索一个理论的观点。