Brain and Behavior of Visual Expectations

描述（由申请人提供）：预知会发生什么，何时发生，以及在哪里发生，可以帮助生物体找到食物并避免捕食者。预备反应利用这种预知来准备感觉和运动系统。神经生理学和神经影像学的最新研究结果表明，部分后顶叶皮质（PPC）可能作为一个准备区。例如，猴子PPC区域的神经元的反应就像是发出信号，表明一个短暂被遮挡的移动目标重新出现。其他研究表明，在猴子看向某个方向或到达某个方向之前，PPC中的细胞开始放电。然而，PPC的功能是有争议的，因为许多研究报告说，各种其他任务-注意力，工作记忆，形状处理-也取决于PPC。 在这项研究中，我们提出了一个假设，即PPC在准备行动时重要地参与了连接感觉和运动信号。在目标1中，我们讨论了预备反应与工作记忆的关系。在目标2的关系，感官预期运动的预期进行了检查，以获得一些理解的一般性和特殊性的准备处理。最后，在目标3中，我们通过询问IPS中的活动是否对预备线索的值敏感来对预备处理进行更细粒度的分析。这些问题将通过功能磁共振成像（fMRI），经颅磁刺激（TMS）和行为实验来解决。

DESCRIPTION (provided by applicant): Foreknowledge about what will happen, when it will happen, and where it will happen, can help an organism find food and avoid predators. Preparatory responses use this foreknowledge to ready sensory and motor systems. Recent findings from neurophysiology and neuroimaging suggest that portions of the posterior parietal cortex (PPC) may function as a preparatory region. For instance, neurons in the monkey PPC region respond as though signaling the re-emergence of a briefly occluded moving target. Other studies have shown that cells in the PPC begin to fire seconds before a monkey looks a certain direction or reaches a certain direction. However, the functionality of the PPC is disputed because many studies have reported that various other tasks - attention, working memory, shape processing - also depend on the PPC. In this grant we advance the hypothesis that the PPC is importantly involved in linking sensory and motor signals in preparation to act. In Aim 1 we address the relationship of preparatory responses to working memory. In Aim 2 the relationship of sensory expectations to motor expectations is examined to gain some understanding of both the generality and specificity of preparatory processing. Last of all, in Aim 3 we do a finer grained analysis of preparatory processing by asking whether activity in the IPS is sensitive to the value of a preparatory cue. These questions will be addressed through functional magnetic resonance imaging (fMRI), transcranial magnetic stimulation (TMS), and behavioral experimentation.