DYNAMIC PROPERTIES OF VISUAL CORTICAL CIRCUITS

描述（改编自申请人的摘要）：突触如何在神经元中形成突触。 纹状体皮层微回路调节信号检测的生理学 皮质神经元？为了解决这个广泛的问题，我们分析了突触的基础， 神经元反应结构在连续的皮层阶段和连接 将信息从一个皮层层传递到下一个皮层层。工作是做出来的 可能的进步，全细胞记录在体内，一种技术， 在视觉过程中诱发的突触后事件的高分辨率视图， 允许单个神经元的细胞内染色。目的1）推拉模型 简单的感受野认为反向对比信号具有 相反的效果：呈现给子区域的明亮刺激引起放电， 而深色的则减少活动。提出了两种机制来说明 为了拉。一种是从丘脑被动撤回兴奋; 另一个是对视觉反应的药理学分析。此外，我们将 确定推拉模型是否充分考虑了 简单感受野的兴奋和抑制，如果它预测 定向调谐目的2）为什么许多复杂的细胞对相同的细胞反应不佳 能很好地驱动简单细胞的刺激？我们的假设是 皮质阶段采用不同的突触机制来调节 刺激选择性如果是真的，那么接受直接丘脑 输入的响应结构应该与外部单元格的响应结构不同 丘脑区这一预测是通过比较细胞的反应， 第4层和第2+3层的人对同一刻板刺激的反应。的 用于从第一皮层到第二皮层的信息传递的解剖基质 阶段通过标记从层4延伸到2+3的连接来确定。 了解大脑在日常生活中是如何运作的， 标准，用以判断在各种过程中发生的变化， 疾病，以及测试开发用于治疗的药物的模型系统 病从这个角度来看，视觉皮层是一个明显的研究场所; 它的功能和解剖结构比任何其他皮质区域都更好地解决。一 对皮层突触机制的更深入理解提供了对以下方面的深入了解： 在疾病期间出错的过程。例如，这里提出的工作 直接关系到弱视研究的一个中心主题， 异常的视觉体验如何导致中央处理的变化。

DESCRIPTION (Adapted From The Applicant's Abstract): How does the synaptic physiology of the cortical microcircuit regulate signal detection in striate cortical neurons? To approach this broad issue we analyze the synaptic basis of neuronal response structures at successive cortical stages and the connections that convey information from one cortical level to the next. The work is made possible by the advance of whole-cell recording in vivo, a technique that gives a highly resolved view of the postsynaptic events evoked during vision and allows intracellular staining of single neurons. AIM 1) The push-pull model of the simple receptive field holds that signals of reverse contrast have the opposite effect: bright stimuli presented to an on subregion evoke firing, whereas dark ones reduce activity. Two mechanisms have been proposed to account for the pull. One is passive withdrawal of excitation from the thalamus; the other is pharmacological analyses of the visual response. Further, we will determine if the push-pull model fully accounts for the spatial distribution of excitation and inhibition in the simple receptive field and if it predicts orientation tuning. AIM 2) Why do many complex cells respond poorly to the same stimuli that drive simple cells well? Our hypothesis is that the successive cortical stages employ different sets of synaptic mechanisms to regulate stimulus selectivity. If true, then complex cells that receive direct thalamic input should have response structures different from those of cells outside thalamic reach. This prediction is tested by comparing responses of cells in layer 4 with those in layer 2+3 to the same stereotyped stimulus. The anatomical substrate for information transfer from the first to second cortical stage is determined by labeling the connections extending from layer 4 to 2+3. 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 resolved than any other cortical region. A deeper understanding of cortical synaptic mechanisms provides insight into processes that go awry during disease. For example, 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.