THE ROLE OF THE PULVINAR IN VISUAL ATTENTION

这个子项目是利用由NIH/NCRR资助的中心拨款提供的资源的许多研究子项目之一。子项目和调查员(PI)可能从另一个NIH来源获得了主要资金，因此可能会出现在其他CRISE条目中。列出的机构是针对中心的，而不一定是针对调查员的机构。目的：丘脑枕核是脑内最神秘的结构之一。在丘脑核团中，它的大小随着进化而增加最大，与灵长类新皮质的大小同步。尽管做出了相当大的努力，但它的功能基本上仍然是完全未知的。两个相关的建议主导了当前关于枕骨的想法，每个建议都有一定的实验支持。然而，这两个想法都没有经过严格的测试，本申请旨在提供对这两个想法的关键测试。第一个想法是枕骨控制定向注意力的空间位置。这一观点得到了损伤研究和生理记录研究的支持--尽管不是决定性的。我们计划通过干扰枕区的活动来直接测试这一想法，同时在纹状体外皮质进行记录。我们知道，定向注意会在纹外神经元的反应获得中产生局部变化；枕骨的激活应该会模仿这种变化，而枕骨的可逆失活应该会消除这种变化。关于枕骨作用的另一种暗示涉及到感觉皮质这种获得性变化的机制。特别是，有人提出，枕骨和皮质结构之间的经常性投射控制着皮质区域之间的信息流；这一调节可能是引导空间注意的任何作用的基础。我们计划用纹状体外皮质的多电极记录来测试这一想法。两个背侧纹外区，即颞中(MT)和内侧上颞区(MST)都连接到枕骨(PLM)的同一亚区，也相互连接-MT为MST提供了一个主要的前馈输入来源。我们将同时从两个结构记录，同时再次扰乱枕骨的活动。如果与枕叶的联系调节视皮层的信息流，我们预测这种干扰将调节MT和MST之间的活动的相互关联。这两个目标的成功都将极大地影响我们对丘脑皮质回路功能的思考。

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.