Electrophysiological indices of task-dependent attentional biasing in humans

描述(由申请人提供)：给定任务目标和一些先验知识，观察者能够以一种提高感知决策和后续行动的速度和准确性的方式提前为感觉事件做准备。有证据表明，这种“自上而下”注意功能的准备，涉及早期(低水平)感觉区感觉神经元活动的瞬时变化。一个常见的发现是，当注意力被分配到某个位置时，通常对刺激做出反应的视觉皮质区域 定位特别是经历了基线兴奋性的增强。然而，关于如何在不同的层级和具有不同的调谐特性的神经元之间的调制模式被定制以促进特定的感知任务的更详细的细节还没有被理解。使预备神经状态适应不同复杂性、难度和背景的任务是一种基本的较高认知能力，已知在许多大脑疾病中会受到损害，如精神分裂症、自闭症和注意缺陷/多动障碍(ADHD)。这项提议的目标是开发、验证和应用新的方法，使我们能够调查这些细节。在以前工作的基础上，我们将使用脑电(EEG)稳态反应来跟踪人类具有特定特性的视觉神经元的皮质兴奋性。在目标1中，我们将利用视觉皮质解剖学的众所周知的几何特性以及简单的信号处理原理来推导出区别指示纹状体(V1)和纹状体外活动的信号。然后，我们将研究任务复杂性对纹状体和纹外皮质空间特定增益调制调用的影响。这可能会调和围绕最早的注意中枢调节的长期争议。在目标2中，我们将使用定向探头刺激场，在单一特征维度--定向--的一系列值上推导出指示神经敏感性的信号。因此，我们将研究在视觉搜索准备期间，注意力权重对特定特征值的分配，比较细微的和粗略的目标-分心物体相似的条件。这将为上下文相关的特征加权提供关键的洞察力，以及它是如何通过改变早期视觉皮质神经元的敏感性来实现的。这两个目标的实现不仅将带来对重大认知问题的新见解，还将建立在认知神经生理学领域具有广泛实用价值的新程序。

DESCRIPTION (provided by applicant): Given a task goal and some prior knowledge, an observer is able to prepare in advance for sensory events in a way that improves the speed and accuracy of perceptual decisions and subsequent actions. There exists evidence that this preparation, a function of "top-down" attention, involves transient alterations to the activity of sensory neurons in early (low-level) sensory areas. One common finding is that when attention is deployed to a certain location, visual cortical regions that normally respond to stimuli at that location specifically undergo an enhancement in baseline excitability. However, the finer details of how the patterns of modulation across neurons at various hierarchical levels and with various tuning properties are tailored to facilitate specific perceptual tasks are not yet understood. Adapting preparatory neural states to tasks of varying complexity, difficulty and context is a fundamental higher cognitive ability that is known to be impaired in many brain disorders such as schizophrenia, autism and attention deficit/hyperactivity disorder (ADHD). The goal of this proposal is to develop, validate and apply novel methods to allow us to investigate these details. Building on previous work, we will use electroencephalographic (EEG) steady-state responses to track cortical excitability in visual neurons with specific properties in humans. In aim 1, we wll exploit well-known geometrical properties of visual cortical anatomy along with simple signal processing principles to derive signals that differentially index striate (V1) versus extrastriate activity. We will then examine the influence of task complexity on the invocation of spatially specific gain modulation in striate and extrastriate cortex. This could potentially reconcile a longstanding controversy surrounding the earliest locus of attention modulation. In aim 2, we will derive signals indexing neural sensitivity across a range of values of a single feature dimension - orientation - using a field of oriented probe stimuli. We will thus examine the allocation of attentional weights to specific feature values during preparation for visual search, comparing across conditions of fine and coarse target-distracter similarity. This will provide key insight ino context-dependent feature-weighting and how it is accomplished by changes to the sensitivity of early visual cortical neurons. The fulfillment of these two aims will not only bring about new insights into major cognitive problems, but will also establish new procedures that will be of broad utility in the field of cognitive neurophysiology.