The Effects of Attention in Human Visual Cortex

描述（由申请人提供）：人类非常善于选择混乱视觉场景的相关部分或嘈杂派对中的相关对话。相比之下，人类在将注意力分散到多种刺激上时往往不那么成功。一个人不能同时读两本书，同时打电话和开车是不明智的。 关于注意力对人类和猴子视觉皮层生理反应的影响，人们已经了解了很多。然而，几乎所有这些工作都涉及选择性注意，即注意力被引导到一个信息源而不是另一个。一般来说，对选择性注意力的研究表明，与不相关的刺激相比，与当前任务相关的刺激在大脑的许多区域中的活动更大。 令人惊讶的是，人们对分散注意力（在同一时间内注意多件事）对神经元反应的影响知之甚少。这种缺乏生理学文献是特别令人惊讶的， 关于分散注意力对行为表现影响的研究历史悠久。很有趣。这些行为研究显示了广泛的影响：对于简单特征的辨别，一次关注多个刺激的成本很小，而对于更高级别的感知任务，例如阅读单词，一次关注多个刺激可能是不可能的。 在这里，我们提出了一系列的行为和成像研究，以检查的生理基础，分散注意力。我们将（1）研究在分配注意力时，任务中的哪些因素会导致成本。特别是，我们将研究是否是刺激或任务的复杂性是一个简单的光栅任务（具体目标1）和复杂的词汇任务（具体目标2）的关键因素。其次，我们将确定当注意力能力有限时，神经反应减少和行为表现受损的原因。特别是，我们将确定注意力限制是否是由于注意力的衰减， 增益，转移到串行处理或抑制刺激之间的相互作用。最后，我们将研究注意调制的空间分布在分散注意：它是否广泛分布在空间和/或功能或分散分配。 文献中的这一空白是 临床重要性。患有自闭症谱系障碍和ADHD的个体表现出不同的注意力分散效应：对注意力分散机制的深入理解可能在将这些行为差异与潜在的神经生理机制联系起来方面至关重要。

DESCRIPTION (provided by applicant): Humans are excellent at selecting the relevant part of a cluttered visual scene or the relevant conversation at a noisy party. In contrast, humans are often not so successful at dividing attention over multiple stimuli. One cannot read two books at once and is it is not wise to talk on a phone and drive at the same time. Much has been learned about the effects of attention on physiological responses in the human and monkey visual cortex. However nearly all of this work has addressed selective attention, which is when attention is directed to one source of information over another. In general, studies of selective attention have shown that activity in many areas of the brain is greater for a stimulus that is relevant to the current task compared to a stimulus that is not relevant. Surprisingly, very littl is known about the effects of divided attention - paying attention to more than one thing on a time - on neuronal responses. This lack of a physiological literature is particularly surprising given the long history of research on the effects of divided attention on behavioral performance. Interestingly. these behavioral studies show a wide range of effects: for discrimination of simple features there can little cost to attended to multiple stimuli at a time, whereas for higher-level perceptual tasks such as reading words it may impossible to attend to more than one stimulus at a time. Here we propose a series of behavioral and imaging studies to examine the physiological basis of divided attention. We will (1) examine what factors in a task result in a cost when dividing attention. In particular we will examine whether it is the complexity of the stimulus or the task that is the critical factor for both a simple grating task (Specific Aim 1) an complex lexical task (Specific Aim 2). Second we will determine the cause of reduced neural responses and impaired behavioral performance when attentional capacity is limited. In particular, we will determine whether attentional limitations are due to attenuation of attentional gain, a shift to serial processing or suppressive interactions between stimuli. Finally we will examine the spatial profile of attentional modulations during divided attention: whether it is spread broadly across space and/or features or allocated discretely. This gap in the literature is of clinical importance. Individuals with autism spectrum disorder and ADHD show differential divided attention effects: a deeper understanding of the mechanism underlying divided attention is likely to prove critical in linking these behavioral differences to underlying neurophysiologica mechanisms.