Cortical & Subcortical Control of Saccades and Attention

描述(申请人提供)：为了生存，动物必须专注于重要的刺激，而忽略不相关的刺激。我们的长期目标是了解大脑如何选择视觉定向的目标，包括眼跳和注意力转移，而不是眼球运动。扫视目标的选择位于感觉和运动系统之间的交界处。这个项目探索了两个传统上被认为是运动区的结构的功能：上丘(SC)，一个对眼跳很重要的皮质下区域，以及额叶眼场(FEF)，一个解剖学上相连的皮质区域。在这两个地区都观察到了与目标选择相关的活动。然而，这些区域是否参与选择要看的地方，或者只是为了准备产生运动而接受与选择相关的活动，仍然是有争议的，特别是对SC来说。我们将通过暂时使SC或FEF的小区域失活，并测试在区分纯粹感觉或运动缺陷与目标选择缺陷的任务中的表现，来检验这些区域在目标选择中发挥功能作用的假设。比较将揭示这两个结构在其对目标选择(目标1)的贡献方面有何不同。我们还将研究SC和FEF的相互作用。通常认为SC处于FEF等皮质区域的控制之下，即使解剖路径也会从SC通向FEF。我们将使用单单位记录和失活来检验SC活动影响FEF中目标选择的假设。这将揭示这两个区域是否主要以前馈方式相互作用，或者来自SC的反馈是否影响皮质目标选择(目标2)。有证据表明，一些相同的大脑区域同时控制眼球运动和注意力转移。我们将通过调查在需要转移焦点注意力的任务中暂时扰乱SC或FEF活动的后果来检验这一假设(目标3)。这些实验将有助于揭示视觉定向系统的架构，从而更好地理解扰乱眼睛运动和注意力的人类神经综合征。

DESCRIPTION (provided by applicant): To survive, animals must orient toward important stimuli while ignoring irrelevant ones. Our long-term goal is to understand how the brain selects targets for visual orienting, including saccadic eye movements and shifts of attention without eye movements. Saccade target selection lies at the interface between sensory and motor systems. This project probes the functions of two structures traditionally regarded as motor areas: the superior colliculus (SC), a subcortical region important for saccades, and the frontal eye field (FEF), an anatomically connected cortical region. Activity correlated with target selection has been observed in both areas. However, it is still debatable, particularly for the SC, whether these areas are involved in selecting where to look, or simply receive selection-related activity in preparation for generating a movement. We will test the hypothesis that these areas play functional roles in target selection by temporarily inactivating small regions of either the SC or FEF and testing performance in tasks that distinguish purely sensory or motor deficits from deficits in target selection. Comparisons will reveal how the two structures differ from each other in their contributions to target selection (Aim 1). We will also study the interactions of the SC and the FEF. It is usually assumed that the SC is under the control of cortical regions such as FEF, even though anatomical pathways also lead from the SC back to the FEF. We will test the hypothesis that SC activity influences target selection in the FEF, using single-unit recording and inactivation. This will reveal whether the two areas interact primarily in a feed-forward manner, or whether feedback from the SC influences cortical target selection (Aim 2). Evidence suggests that some of the same brain areas control both eye movements and attention shifts. We will test this hypothesis by investigating the consequences of temporarily disrupting activity in the SC or FEF on tasks requiring shifts of focal attention (Aim 3). These experiments will help to reveal the architecture of the visual orienting system, leading to a better understanding of human neurological syndromes that disrupt eye movements and attention.