Dynamic Properties of Visual Cortical Circuits

视觉皮层回路的动态特性

• 批准号: 7736685
• 负责人: Judith A Hirsch
• 金额: $ 40.69万
• 依托单位: UNIVERSITY OF SOUTHERN CALIFORNIA
• 依托单位国家: 美国
• 财政年份: 1993
• 资助国家: 美国
• 起止时间: 1993-07-01 至 2012-09-29
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7736685
• 关键词: Address; Amblyopia; Anatomy; Back; Biological Models; Brain; Cell Nucleus; Cells; Computer Analysis; Computer-Assisted Image Analysis; Disease; Event; Eye; Feedback; Feeds; Felis catus; Goals; In Situ; In Vitro; Individual; Interneurons; Knowledge; Lateral Geniculate Body; Learning; Literature; Location; Maps; Methods; Metric; Modeling; Neurons; Pattern; Pharmacology; Pilot Projects; Play; Positioning Attribute; Process; Property; Research; Reticular Cell; Reticular Formation; Retina; Retinal; Retinal Ganglion Cells; Rodent; Role; Route; Sampling; Sensory Process; Shapes; Sorting - Cell Movement; Stimulus; Synapses; Testing; Thalamic structure; Time; Training; Ursidae Family; Vision; Visual; Visual Cortex; Visual Fields; Visual Pathways; Work; base; cell type; drug testing; experience; extracellular; ganglion cell; in vivo; interdisciplinary approach; public health relevance; receptive field; research study; response; spatiotemporal; visual map; visual process; visual processing

Description (provided by applicant): The inhibitory circuits of the visual thalamus dominate local processing and influence all information that relay cells transmit from the eye to the brain. These circuits divide into two major groups based on position in the visual pathway. Local interneurons in the main layers of the lateral geniculate nucleus receive input from the retina and provide feedforward inhibition to relay cells and each other. The perigeniculate sector of the reticular formation is innervated by relay cells and feeds back inhibition to these cells in turn. Despite the importance of these suppressive networks to vision, little is known about how they operate in situ. The proposed research addresses this gap by investigating inhibitory cells in the perigeniculate and lateral geniculate nuclei using an interdisciplinary approach that combines intracellular recording from identified interneurons and extracellular multiunit recording with computational analysis and modeling. Aim 1) How do the spatiotemporal receptive fields of relay cells and local interneurons compare? Relay cells have receptive fields built from concentric On and Off subregions with a push-pull layout of excitation and inhibition; where bright stimuli excite, dark inhibit and vice versa. The excitation (push) comes from retinal ganglion cells whose receptive fields have the same location and center sign (On or Off) as that of the target relay cell. This aim tests the hypothesis that the inhibition (pull) is routed through interneurons driven by ganglion cells whose fields have similar positions but the opposite sign as that of the target relay cell. Aim 2) Do relay cells and local interneurons sample and integrate feedforward input the same way? Many thalamic neurons receive input from more than one ganglion cell. This aim asks how retinothalamic convergence redraws the map of visual space laid out in the eye. Additional experiments explore how previously established disparities between the anatomy and pharmacology of relay cells vs. interneurons produce commensurate differences in synaptic integration. Aim 3) Does feedback inhibition from the perigeniculate nucleus operate over multiple spatial scales? The perigeniculate nucleus is widely believed to regulate global levels of activity rather than to play a spatially targeted role in visual processing. Yet, mounting evidence counters this simple view. This aim explores circuits that build reticular receptive fields and investigates the possibility that these fields range widely in size, even at the same position in the visual field. SIGNIFICANCE: Knowledge of how the healthy brain operates provides a standard against which to judge changes that result from various disorders, as well as a model system for testing drugs developed to treat illness. Thus, understanding how inhibitory circuits in the thalamus normally function is necessary to identify mechanisms that go awry during disease. For example, this project bears directly on a key theme in research on amblyopia, the examination of how abnormal visual experience leads to changes in central processing. PUBLIC HEALTH RELEVANCE: This project investigates feedforward and feedback inhibitory circuits in the visual thalamus. Understanding how thalamic circuits function in the healthy brain is necessary to identify mechanisms that go awry during disease. For example, the work proposed here bears directly on a key theme in research on amblyopia, the examination of how abnormal visual experience leads to changes in central processing.

描述（由申请人提供）：视觉丘脑的抑制回路主导着局部处理，并影响中继细胞从眼睛传播到大脑的所有信息。这些电路根据视觉途径中的位置分为两个主要组。横向基因核的主要层中的局部神经元从视网膜接收输入，并提供了对中继细胞和彼此的饲料抑制作用。网状形成的周期性扇形通过继电器细胞支配，并反馈抑制这些细胞。尽管这些抑制性网络对视觉具有重要意义，但对它们的原位运作方式知之甚少。提出的研究通过使用跨学科方法来研究周围和侧向基因核中的抑制细胞来解决这一差距，该方法结合了鉴定出的中间神经元的细胞内记录和细胞外多单位记录与计算分析和建模。目标1）如何比较中继细胞和局部神经元的时空接受场？继电器细胞具有由同心开关和关闭子区域建立的接收场，并具有推动的激发和抑制作用。明亮刺激激发的地方，深色抑制，反之亦然。激发（推动）来自视网膜神经节细胞，其接收场的位置和中心符号（开或关）与目标继电器细胞相同。该目标检验了以下假设：抑制（拉）是通过神经节细胞驱动的中间神经元路由的，其磁场的位置相似，但符号与目标继电器细胞的迹象相反。 AIM 2）继电器单元和局部神经元样品样品并以相同的方式集成进发输入？许多丘脑神经元从一个以上的神经节细胞接收输入。这个目标询问视网膜融合如何重新绘制眼睛中铺设的视觉空间图。其他实验探讨了以前的解剖结构与中继神经元的药理学之间的差异如何产生突触整合的相应差异。目标3）来自周围核的反馈抑制是否在多个空间尺度上运行？人们普遍认为，核核可以调节全球活性水平，而不是在视觉处理中起空间靶向作用。然而，安装证据反驳了这种简单的观点。这个目的探索了建立网状接收场的电路，并研究了这些磁场的大小范围广泛，即使在视野中相同的位置也是如此。意义：了解健康大脑运作的知识提供了一种标准，可以判断各种疾病导致的变化，以及用于测试用于治疗疾病的药物的模型系统。因此，了解丘脑中通常功能中的抑制回路对于确定疾病期间出现问题的机制是必要的。例如，该项目直接遵循有关弱视研究的关键主题，对异常视觉体验的研究如何导致中央处理变化。公共卫生相关性：该项目调查了视觉丘脑中的前馈和反馈抑制回路。了解丘脑电路在健康大脑中的作用是为了确定疾病期间出现问题的机制。例如，这里提出的工作直接依靠有关弱视研究的关键主题，对异常视觉体验的研究如何导致中央处理变化。