Interaction of Visual and Oculomotor Signals in Cortex

视觉空间注意力是一种关键的心理操作，它允许我们在面对过多的视觉输入时选择性地只处理相关信息。理解这种现象的潜在神经机制是我们理解认知的神经基础的核心，也是改善人类患者注意力障碍的希望的核心。我们和其他最近的工作表明，更好地了解视觉和动眼肌机制之间的相互作用可能是建立空间注意因果神经基础的关键。因此，这项建议的长期目标是了解灵长类动物大脑中动眼肌和视觉机制之间的相互作用。这一目标将通过以下三个目标来实现：我们的第一个目标是测试额叶皮层扫视机制在指导隐蔽空间注意和驱动视觉皮层选择中的因果作用。额眼区（FEF）内的神经元活动将被药理学灭活，我们将检查这对猴子自愿将注意力隐蔽地引导到空间受影响部分的能力的影响，以及在多大程度上被广泛观察到的脑外区V4的注意力相关神经被消除。我们的第二个目标是比较FEF微刺激与隐蔽空间注意的已知效应在层外皮层观察到的视觉增益变化。我们将研究在被动注视的猴子中，阈下FEF微刺激引起的V4反应变化如何与在训练为主动引导隐蔽注意的动物中观察到的调节相似。我们的第三个目的是检验视觉刺激产生扫视的概率与视觉皮层对该刺激的反应增益之间的关系。我们将通过系统地改变FEF微刺激的参数来直接操纵跳眼概率，并研究其影响

Visual spatial attention is a critical mental operation that allows us to selectively process only relevant information in the face of an overabundance of visual input. Understanding the underlying neural mechanisms of this phenomenon is central to our understanding of the neural basis of cognition and central to any hope of ameliorating disorders of attention in human patients. Ours and other recent work suggests that better knowledge of the interplay between visual and oculomotor mechanisms may be the key to establishing a causal neural basis of spatial attention. Thus, the long-term goal of this proposal is to understand the reciprocal interactions between oculomotor and vision mechanisms in the primate brain. This goal will be pursued via the following three aims: Our first aim is to test the causal role of frontal cortical saccade mechanisms in directinq covert spatial attention and in drivinq selection in visual cortex. Neuronal activity within the frontal eye field (FEF) will be inactivated pharmacologically and we will examine the effect of this on the ability of monkeys to voluntarily direct attention covertly to the affected part of space, and on the degree to which the widely observed neural correlates of attention in extrastriate area V4 are eliminated. Our second aim is to compare the changes in visual qain observed in extrastriate cortex during FEF microstimulation with the known effects of covert spatial attention. We will examine how the changes in V4 responses caused by subthreshold FEF microstimulation in passively fixating monkeys parallel the modulations observed in animals trained to direct covert attention voluntarily. Our third aim is to examine the relationship between the probability that a saccade will be made to a visual stimulus and the gain of visual cortical responses to that stimulus. We will directly manipulate saccade probability by systematically varying the parameters of FEF microstimulation and study the effect of this manipulation on the gain of visual responses in area V4. This research may provide insight into the physiological basis of disorders of attention in humans, which affect up to 5% of children in the U.S, and may also provide insight into problems of visual-oculomotor coordination, such as dyslexia, which affects approximately 10% of U.S. citizens.