Functional relationships between visual cortex and thalamus

项目摘要 我们将首先使用小鼠脑的体外切片来研究丘脑皮质 视觉系统中两个方向的相互作用，集中在皮层区域V1和V2 丘脑核LGN和LP。然后，我们建议开发体内制剂来测试 来自体外工作的假设。我们大量使用光遗传学与其他 刺激范例以激活特定通路并使用单细胞记录和 电流源密度分析来测量响应。我们特别感兴趣的是 两种不同的皮质丘脑投射。一个从第6层发出，并反馈到 丘脑核支配该区域;我们假设其主要功能是抑制 通过多种互补机制的丘脑皮层传递。另一个散发出 从第5层，并组织在前馈的方式，神经支配丘脑区域，不 支配其皮质区;我们假设这代表了经丘脑， 皮质-丘脑-皮质通路与直接皮质-皮质投射平行。 最后，我们还将检验这两条途径同时起作用的假设 检测方式来控制信息流。这可以提供更普遍的见解 关于皮质功能，特别是关于不同皮质功能的新证据， 区域可以根据行为需要动态地协作。

PROJECT SUMMARY We shall initially use in vitro slice preparations from the mouse brain to study thalamocortical interactions in both directions in the visual system, concentrating on cortical areas V1 and V2 and thalamic nuclei LGN and LP. We then propose to develop in vivo preparations to test hypotheses from the in vitro work. We make heavy use of optogenetics in combination with other stimulation paradigms to activate specific pathways and use both single cell recording and current source density analysis to measure responses. We are particularly interested in the role of the two distinct corticothalamic projections. One emanates from layer 6 and feeds back to the thalamic nucleus innervating that area; we hypothesize that its main function is to depress thalamocortical transmission by multiple complementary mechanisms. The other emanates from layer 5 and is organized in a feed forward fashion, innervating thalamic regions that do not innervate its cortical area; we hypothesize that this represents the initiation of a transthalamic, cortico-thalamo-cortical pathway organized in parallel with direct corticocortical projections. Finally, we shall also test the hypothesis that these dual pathways operate in a coincidence detection manner to control information flow. This could provide more general insights regarding cortical functioning, particularly with respect to new evidence that different cortical areas can dynamically cooperate depending on behavioral needs.