DYNAMIC PROPERTIES OF VISUAL CORTICAL CIRCUITS

视觉皮质回路的动态特性

• 批准号: 2163243
• 负责人: Judith A Hirsch
• 金额: $ 10.89万
• 依托单位: ROCKEFELLER UNIVERSITY
• 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 1998-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/2163243
• 关键词: ferrets; intercellular connection; neural information processing; neural inhibition; neuroanatomy; neurophysiology; single cell analysis; synapses; visual cortex; visual pathways

The receptive fields of neurons in layer 4 of the ferret and cat striate cortex are oriented, rectangular and frequently end-inhibited as well. this complexity stands in marked contrast to the receptive fields of cells one synapse away in the lateral geniculate nucleus, which have a circular, center-surround organization. The long-term goal of the project described here is to investigate the synaptic physiology of characteristic pathways in striate cortex to understand, stepwise, how sensory input is restructured by the synapses it traverses. In 1965, Hubel and Wiesel proposed a model circuit for the response property of end-stopping. They suggested that cells with long receptive fields might overlap the end-stopped regions and suppress activity there. Over the intervening decades, the results of anatomical investigations and extracellular recordings made in vivo have led to a more detailed formulation of the original hypothesis. current theory holds that end- stopping in layer 4 is relayed from layer 6 through a disynaptic inhibitory connection. The specific identity and connectivity of the cells providing the inhibition remain to be established. A central prediction of this hypothesis is that the activation of layer 6 should have a net inhibitory effect on synaptic events driven by geniculocortical inputs for cells corresponding to those which are end- inhibited. Whole-cell recordings from brain slices will be made to test this prediction. Specifically, the responses to activation of the thalamic and interlaminar pathways alone as well as together will be compared for single cells in layer 4. All cells will be labelled intracellularly to allow correlation between physiology and anatomy. When necessary, recordings will be made from neurons that are visually identified prior to study in order to ensure that information about key minority populations such as inhibitory cells is acquired. Pathway- specific integration will then be examined at a finer grain by analyzing the unitary response provided from one cell to the next at each major synaptic station along the thalamic and interlaminar circuits. A knowledge of how the brain operates in the everyday situation provides a standard against which to judge changes that occur in the course of various disorders as well as a model system on which to test drugs developed to treat illness. From this perspective, the visual cortex is an obvious site to study; its function and anatomy are better understood than any other cortical region. A deeper understanding of synaptic mechanisms provides insight into the processes that go awry during disease. The work proposed here bears directly on a central theme in research on amblyopia, the examination of how abnormal visual experience leads to changes in central processing.

雪貂和猫曲线的第4层神经元的接受场 皮质是定向的，矩形的，并且经常被束缚。 这种复杂性与与接受场的形成鲜明对比 细胞在横向元素核中一个突触，该核具有A 循环，中心围栏组织。 长期目标 这里描述的项目是为了研究 逐步理解的条纹皮层中的特征途径 感觉输入通过它穿越的突触进行了重组。 1965年，Hubel和Wiesel提出了一个模型电路 末端的属性。 他们提出长期接受的细胞 场可能会重叠末端的区域并抑制那里的活动。 在随后的几十年中，解剖研究的结果 体内制作的细胞外记录导致了更详细的 原始假设的表述。 当前的理论认为 在第4层停止从第6层传递到丝毫 抑制连接。 特定的身份和连通性 提供抑制作用的细胞仍有待确定。 该假设的核心预测是层的激活 6应对由驱动的突触事件产生净抑制作用 对应于末端的细胞的基因皮质输入 抑制。 将制作大脑切片的全细胞记录进行测试 这个预测。 具体而言，对激活的反应 仅丘脑和层间途径以及一起 比较第4层中的单个单元格。所有单元均将标记 细胞内允许生理和解剖学之间的相关性。 必要时，将通过视觉上的神经元进行录音 在学习之前确定，以确保有关关键的信息 获取少数群体（例如抑制细胞）。 途径 然后，将通过分析在细晶粒上检查具体的整合 每个主要的一个单元从一个小区提供的统一响应 沿丘脑和层间电路的突触站。 了解大脑在日常情况下的运作方式 判断在此过程中发生的变化的标准 各种疾病以及测试药物的模型系统 开发以治疗疾病。 从这个角度来看，视觉皮层是 一个明显的研究地点；更好地理解其功能和解剖 比任何其他皮质区域。 对突触的更深入的了解 机制可洞悉对过程中出现问题的过程 疾病。 这里提出的作品直接以中心为主题 对弱视的研究，检查异常视觉体验的研究 导致中央处理的变化。