THE ROLE OF THE PULVINAR IN VISUAL ATTENTION

该子项目是利用NIH/NCRR资助的中心赠款提供的资源的许多研究子项目之一。子项目和研究者（PI）可能从另一个NIH来源获得主要资金，因此可以在其他CRISP条目中表示。所列机构为中心，不一定是研究者所在机构。目的：丘脑枕核是脑内最神秘的结构之一。在丘脑核团中，它显示出随着进化而增加的最大尺寸，与灵长类动物新皮层的尺寸保持同步。尽管作出了相当大的努力，但其功能基本上仍然完全未知。两个相关的建议主导了当前对枕的思考，每个都有一些实验支持。然而，两者都没有经过严格的测试，并且本申请旨在提供对这两种想法的这种严格测试。第一种观点认为枕控制着定向注意的空间位置。这一想法得到了病变研究和生理记录研究的支持--尽管不是结论性的。我们计划直接测试这一想法的扰动活动枕，同时记录在纹外皮层。我们知道，定向注意引起的纹状体外神经元的反应增益的局部变化;枕的激活应该模仿这种变化，而枕的可逆失活应该消除它。枕的作用的另一个建议是关于感觉皮层中这种增益变化的机制。特别是，有人认为枕和皮质结构之间的周期性投射控制了皮质区域之间的信息流;这种调节可能是指导空间注意的任何作用的基础。我们计划在纹外皮层使用多电极记录来测试这个想法。两个背侧纹外区，中颞叶（MT）和内侧上级颞叶（MST）都连接到枕（Plm）的同一细分，也相互连接- MT提供了一个主要的前馈输入源MST。我们将同时从两个结构记录，同时再次干扰枕的活动。如果与枕的联系调节视皮层的信息流，我们预测，这种扰动将调制MT和MST之间的活动的交叉相关性。任何一个目标的成功都将极大地影响我们对丘脑皮层回路功能的思考。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Objective: The pulvinar nucleus of the thalamus is one of the most enigmatic structures in the brain. Of thalamic nuclei, it shows the largest increase in size with evolution, keeping pace with the size of primate neocortex. Despite considerable effort, its function remains essentially completely unknown. Two related suggestions dominate current thinking about the pulvinar, and each has some experimental support. Neither, however, has been critically tested, and the present application is intended to provide this critical test of both ideas. The first idea is that the pulvinar controls the spatial location of directed attention. This idea has support - though not conclusive - from lesion studies and physiological recording studies. We plan to directly test this idea by perturbing activity in the pulvinar while recording in extrastriate cortex. We know that directed attention produces local changes in the gain of response of extrastriate neurons; activation of the pulvinar should mimic this change and reversible inactivation of the pulvinar should eliminate it. The other suggestion for the role of the pulvinar concerns the mechanism of such gain changes in sensory cortex. In particular, it has been suggested that recurrent projections between the pulvinar and cortical structures control the flow of information between cortical areas; this regulation might underlie any role in directing spatial attention. We plan to test this idea using multiple electrode recording in extrastriate cortex. Two dorsal extrastriate areas, the middle temporal (MT) and the medial superior temporal (MST) are both connected to the same subdivision of the pulvinar (Plm), and also connected with each other - MT provides a dominant source of feedforward input to MST. We will record from both structures simultaneously while again perturbing the activity in the pulvinar. If the connections with the pulvinar regulate information flow in visual cortex, we predict that such perturbation will modulate the cross-correlation of activity between MT and MST. Success on either aim will dramatically influence our thinking about the function of thalamocortical circuits.