Synaptic Organization of the Primate Pulvinar Nucleus

在一个不断为我们提供大量感官信息的世界中，重要信号的选择和增强至关重要。普遍认为枕核是唯一参与这一过程。然而，枕执行这一功能的机制尚不清楚。一些定向注意的模型已经提出，枕核在一个网络中充当枢纽，该网络整合了来自广泛皮层区域的输入，以将注意力引导到突出的视觉目标。这些模型预测，投射到不同皮层区域和从不同皮层区域投射的神经元在枕核内突触连接，以链接与视觉空间位置、记忆和动机相关的各种信号。为了验证这一理论，研究者建议在超微结构水平上研究枕核、后扣带回和顶下小叶之间的联系。此外，他们建议检查前顶盖和脚桥被盖皮质下输入的突触目标。这些区域的活动分别与眼球运动和注意力状态相关，也被预测有助于视觉注意力网络。这些研究的结果将有助于了解皮质和皮质下的输入如何在结构上相互作用的灵长类动物枕核的突触回路。通过研究实验动物的这些神经回路，我们可以开始了解正常注意力过程的机制，以及它们如何受到疾病的影响。

Lay summaryIn a world that continually supplies us with a multitude of sensory information, the selection and enhancement of important signals is crucial. There is general agreement that the pulvinar nucleus is uniquely involved in this process. However the mechanisms by which the pulvinar carries out this function are, as yet, unknown. Several models of directed attention have proposed that the pulvinar nucleus acts as a hub in a network that integrates inputs from widespread cortical areas to direct attention to salient visual targets. Such models predict that neurons that project to and from different cortical areas, are synaptically connected within the pulvinar nucleus to link diverse signals related to visual spatial location, memory, and motivation. To test this theory, the investigators propose to examine, at the ultrastructural level, connections between the pulvinar nucleus the posterior cingulate gyrus, and the inferior parietal lobule. In addition, they propose to examine the synaptic targets of subcortical inputs from the pretectum, and the pedunculopontine tegmentum. These areas, in which activity is correlated respectively with eye movements and attentional state, are also predicted to contribute to networks underlying visual attention. The results of these studies will help to understand how cortical and subcortical inputs structurally interact within the synaptic circuitry of the primate pulvinar nucleus. By studying these neural circuits in experimental animals, we can begin to understand the mechanisms underlying normal attentional processes, and how they are affected by disease.