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.

雪貂和猫纹状体第4层神经元的感受野 皮质是定向的、矩形的，并且经常也是末端抑制的。 这种复杂性与 在外侧膝状体核的一个突触之外的细胞， 圆形的中心环绕的结构 的长期目标 这里描述的项目是研究突触生理学， 纹状皮层的特征通路来理解，逐步地， 感觉输入由它穿过的突触来重构。 1965年，Hubel和Wibel提出了响应的模型电路 终止性质 他们认为，具有长时间感受性的细胞 场可能与终止区域重叠并抑制那里的活动。 几十年来，解剖学研究的结果 和细胞外记录在体内进行了更详细的研究， 对原始假设的表述。 目前的理论认为， 在第4层中的停止是从第6层通过双突触传递的， 抑制性连接 的特定身份和连接性， 提供抑制作用的细胞仍有待建立。 这一假说的一个中心预测是， 6应该对突触事件有净抑制作用， 膝状皮质的输入细胞对应于那些端- 压抑 将对大脑切片进行全细胞记录， 这个预测。 特别是，对激活的反应， 丘脑和层间通路单独以及一起将是 与第4层中的单个细胞相比。 所有细胞将被标记 以允许生理学和解剖学之间的关联。 在必要时，记录将从神经元， 在研究之前确定，以确保有关关键信息 少数群体如抑制性细胞被获得。 途径- 然后，通过分析，在更细的粒度处检查特定的积分。 从一个细胞到下一个细胞提供的单一响应， 突触站沿着丘脑和层间回路。 了解大脑在日常生活中是如何运作的， 一个标准，用以判断在过程中发生的变化， 各种疾病以及测试药物的模型系统 是用来治疗疾病的 从这个角度来看，视觉皮层是 一个明显的研究地点;它的功能和解剖学被更好地理解 比其他任何皮层区域都要多 更深入地了解Synaptic 机制提供了深入了解过程中出错， 疾病 这里提出的工作直接关系到一个中心主题， 研究弱视，检查异常的视觉体验如何 导致中央处理的变化。