DYNAMIC PROPERTIES OF VISUAL CORTICAL CIRCUITS

描述(改编自申请人的摘要)：突触是如何 大脑皮层微电路调节纹状体信号检测的生理学 大脑皮层神经元？为了探讨这个广泛的问题，我们分析了 连续皮质阶段的神经元反应结构及其联系 将信息从一个大脑皮层传递到下一层。作品完成了 通过体内全细胞记录的进步成为可能，这项技术使 视觉和视觉过程中诱发的突触后事件的高分辨率视图 允许对单个神经元进行细胞内染色。目标1)推拉模型 简单感受野认为相反对比信号具有 相反的效果：给予ON分区的明亮刺激会引起激发， 而黑暗者则会减少活动。已经提出了两种机制来说明 为了拉力。一种是被动地从丘脑撤走兴奋； 另一种是对视觉反应的药理学分析。此外，我们还将 确定推-拉模型是否完全考虑了 简单感受野中的兴奋和抑制，如果它预测 定向调整。目标2)为什么许多复杂的细胞对相同的 能很好地驱动简单细胞的刺激？我们的假设是，连续的 皮质阶段使用不同的突触机制来调节 刺激选择性。如果是真的，那么接受直接丘脑的复杂细胞 输入的响应结构应与外部单元格的响应结构不同 丘脑的触角。这一预测通过比较细胞在 第四层与第二层的第三层给相同的刻板印象刺激。这个 从第一皮质到第二皮质信息传递的解剖学基础 阶段通过标记从第4层延伸到第2 3层的连接来确定。 了解大脑在日常情况下是如何运作的提供了一个 用于判断在不同的 疾病，以及用来测试治疗药物的模型系统 生病了。从这个角度来看，视觉皮质显然是一个值得研究的地方； 它的功能和解剖比任何其他皮质区域都要好。一个 对皮质突触机制的更深入了解有助于深入了解 在疾病期间出错的过程。例如，这里提出的工作 与弱视研究的一个中心主题直接相关，弱视的检查 不正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.