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: 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
• 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

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转变的部位，从而产生视觉世界的表征。其中一个主要的转变是取向选择性的出现。然而，V1中定向选择性的功能组织在不同物种间表现出不同的形式。在灵长类动物和食肉动物中，它在地形上组织在皮层上，但在啮齿动物中没有明显的组织，但啮齿动物仍然表现出定向选择性。描述定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来指导共享选择性的神经元之间的连接。两种不同的假说被提出来解释啮齿动物V1中无功能组织的定向选择性的出现。在一种假设中，尽管没有皮质的地形组织，但具有共同取向偏好的神经元之间可能存在特定的突触连接。另外，一项计算研究表明，定向选择性可能来自非特异性网络连接，在兴奋性和抑制性输入平衡的约束下（“平衡网络模型”）。这两种假设并不是相互排斥的，目前也有证据表明这两种假设都存在，但这两种假设在多大程度上反映了啮齿动物V1定向选择性的实际联系尚不清楚。我们建议的目标是通过实验和计算研究来解决平衡网络和特定皮层连接对V1定向选择性产生的相对贡献。拟议的研究分为三个具体目标，将协同开展，并将整合理论