Brain and Behavior of Visual Expectations

描述(由申请人提供)：对将要发生的事情、发生时间和发生地点的预知，可以帮助有机体寻找食物和躲避捕食者。预备性反应利用这种先见之明为感觉和运动系统做好准备。神经生理学和神经成像的最新发现表明，后顶叶皮质(PPC)的一部分可能作为准备区发挥作用。例如，猴子PPC区的神经元的反应就像是发出信号，表明短暂闭塞的运动目标重新出现。其他研究表明，PPC中的细胞在猴子看向某个方向或到达某个方向之前几秒钟就开始放电。然而，PPC的功能存在争议，因为许多研究报告称，各种其他任务--注意力、工作记忆、形状处理--也依赖于PPC。 在这项研究中，我们提出了一种假设，即PPC在连接感觉和运动信号以准备行动方面发挥了重要作用。在目标1中，我们讨论了准备反应与工作记忆的关系。在目标2中，我们考察了感觉期望和运动期望之间的关系，以获得对准备加工的一般性和特殊性的一些理解。最后，在目标3中，我们通过询问IPS中的活动是否对准备线索的值敏感来对准备过程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.