Neural mechanisms of distractor filtering in the parietal cortex

描述（由申请人提供）：大脑是如何过滤分散注意力的视觉信息的？众所周知，显著的视觉刺激可以引起短暂的跳跃性或注意力捕获。如果目标是快速定位到外围的潜在捕食者，这种现象在生态学上是有用的，但如果它分散了对其他目标的注意力，如监视难以捉摸的猎物，这种现象是非常有害的。因此，过滤分散注意力、无关的视觉信息的神经机制对于防止浪费的跳眼或注意力转移至关重要。这种过滤可能是视觉刺激的竞争性神经表征之间的横向抑制相互作用的直接结果，尽管这些过程的细节尚未得到很好的理解。猴子的侧顶叶内区（LIP）编码空间位置的相对优先级，该脑区的活动可以可靠地预测注意力的位置或即将到来的跳眼的目标。在LIP的“显著性地图”中，空间位置通过它们的活动来竞争注意力和扫视优先级。先前的研究已经探索了“自上而下”的兴奋性过程，如动机或注意力如何增强LIP中与行为相关刺激相关的活动，从而增加了它们在该地图上的相对优先级。然而，初步证据表明，LIP的侧抑制相互作用与这些兴奋性过程协同作用，可能对过滤分散注意力的信息和解决刺激之间的竞争至关重要，尽管这一点尚未被探索。在这个提议中，我的目标是系统地探索LIP中侧抑制相互作用在过滤分散注意力的视觉信息中的作用，并确定这与清醒行为猴子的跳眼行为之间的关系。我们将结合心理物理和生理记录来研究以下3个目标：1)表征LIP中侧抑制的时空特性及其如何受到预期奖励的调节；2)确定这些过程如何与跳眼行为相关；3)通过配对电极记录来直接比较竞争刺激的反应，探索分心物过滤的机制。这项研究有望让我们深入了解空间注意和跳眼决策过程背后的一般神经机制。这一建议为在知觉和动眼力行为方面表现出极度缺陷的顶叶患者提供了显著的健康益处。前两个目标将直接表征未探索的正常功能领域，第三个目标可能导致未来药物靶向的细胞群鉴定。

DESCRIPTION (provided by applicant): How does the brain filter distracting visual information? It is well known that salient visual stimuli can elicit transient saccadic or attentional capture. This phenomenon is ecologically useful if the goal is to rapidly orient to a potential predator in the periphery, but highly detrimental if it distracts from a different goal such as monitoring elusive prey. Therefore, neural mechanisms for filtering distracting, irrelevant visual information are crucial for preventing wasteful saccadic or attentional shifts. This filtering may emerge as a direct consequence of lateral suppressive interactions between competing neural representations of visual stimuli, though the details underlying these processes are not well understood. The lateral intraparietal area (LIP) of the monkey encodes the relative priority of spatial locations, and activity in this brain area can reliably predict the locus of attention or the target of an upcoming saccade. Within LIP's "salience map," spatial locations compete using their activity for attentional and saccadic priority. Previous studies have explored how "top-down" excitatory processes such as motivation or attention can enhance the activity associated with behaviorally relevant stimuli in LIP, thus increasing their relative priority on this map. However, preliminary evidence suggests that lateral suppressive interactions in LIP operate in tandem with these excitatory processes and may be crucial for filtering distracting information and resolving competition between stimuli, though this has not yet been explored. In this proposal, my goal is to systematically explore the role of lateral suppressive interactions in LIP in filtering distracting visual information, and determine how this is related to saccadic behavior in the awake behaving monkey. We will use a combination of psychophysics and physiological recordings in LIP to investigate the following 3 aims: 1) Characterize the spatiotemporal properties of lateral suppression in LIP and how they are modulated by expected reward 2) Determine how these processes are related to saccadic behavior, and 3) Explore the mechanism of distractor filtering by using paired electrode recordings to directly compare the responses of competing stimuli. This research will hopefully give us insight into the general neural mechanisms that underlie the processes of spatial attention and saccadic decision making. This proposal offers significant health benefits to parietal patients, who exhibit extreme deficits in perception and oculomotor behavior. The first two aims would directly characterize unexplored areas of normal functioning, and the third aim could potentially lead to the identification of cellular populations for future drug targeting.