The activity of V4 in free viewing visual search

当观察自然世界时，灵长类动物使用扫视眼球运动来扫描环境和 专注于感兴趣的对象，以获得最大的视觉处理能力。然而，由于存在许多潜在的对象 在视觉场景中，选择一个扫视目标是至关重要的。将眼球运动选择到 特定的项目基于代表突出世界的地形图。外侧顶叶皮质 (嘴唇)可能会构建这个显著图，因为他的视觉运动区可以定位与行为相关的物体 将有目的的扫视行为引导到特定对象所必需的表格处理 功能。另一方面，V4作为能够选择扫视的视觉区域是一个很好的候选者 目标。它是负责物体处理的纹外皮质，具有与眼睛相关的活动 移动并将直接投影发送到嘴唇。因此，我们建议区域V4为以下对象提供视觉输入 用嘴唇表示的突出度图，它引导以自然视觉为特征的眼跳模式。 正在处理。我们设计了一个免费观看的视觉搜索任务，猴子可以完全自由地移动他们的 眼睛并报告任务的结果，做一个非目标的手部运动。我们将研究 从单个V4和嘴唇细胞记录的猴子在执行任务时的动眼行为和神经活动 这项任务研究以下3个目标：1)我们将表征V4神经元的突触前活动 描述他们对指导后续扫视的贡献。2)我们将了解V4使用的机制 基于对象特征识别行为相关的扫视目标。3)我们将测试 V4和LIP之间的连接。通过在这个相同的任务中探索V4和LIP之间的关系，我们 健康相关性：有顶枕病变的患者有视觉障碍和 产生眼球运动。通过了解正常功能视觉行为背后的生理学， 我们可以为这些患者更好地诊断和设计康复方案。

When viewing the natural world, primates use saccadic eye movements to scan the environment and fixate on objects of interest for maximal visual processing. However, since there are many potential objects of interest in the visual scene, choosing a saccade target is crucial. Selection of an eye movement to a particular item is based on a topographic map representing the salient world. Lateral intraparietal cortex (LIP) might construct this salience map sincelhis visuomotor area can localize a behaviorally relevant object for a gaze shift and projects to areas involved in executing eye movements. However, LIP lacks the visual form processing necessary to guide purposeful saccadic behavior to a particular object based on its features. On the other hand, V4 is an excellent candidate as a visual area capable of selecting saccade targets. It is an extrastriate cortex responsible for object processing, has activity correlated to eye movements and sends direct projections to LIP. Thus, we propose that area V4 provides the visual input for the salience map represented in LIP which guides saccade patterns characterized by natural vision. The main objective of this experiment is to characterize the physiological response properties of V4 neurons during free viewing visual search to better understand the role they play in more natural visual processing. We designed a free viewing visual search task where monkeys are entirely free to move their eyes and report the results of the task by making a non-targeting hand movement. We will examine oculomotor behavior and neural activity recorded from single V4 and LIP cells while the monkeys perform this task to investigate the following 3 aims: 1) We will characterize the presaccadic activity of V4 neurons to describe their contribution to guiding subsequent saccades. 2) We will look at the mechanisms V4 uses to identify a behaviorally relevant saccade target based on object features. 3) We will test the function of the connection between V4 and LIP. By exploring the relationship between V4 and LIP in this identical task, we can understand better the link between visual form processing and selection of the eye movement to ultimately locate a search target during natural vision. HEALTH RELEVANCE: Patients with parietal and occipital lesions have difficulty in visual perception and generating eye movements. By understanding the physiology underlying normal functioning visual behavior, we can better diagnose and design rehabilitaion programs for these patients.