The activity of V4 in free viewing visual search

描述（由申请人提供）：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并注视感兴趣的物体以进行最大的视觉处理。然而，由于在视觉场景中有许多潜在的感兴趣的对象，因此选择扫视目标是至关重要的。对特定项目的眼球运动的选择基于表示显著世界的地形图。外侧顶叶内皮层（LIP）可能会构建这种显着性地图，因为这个视觉区域可以定位一个行为相关的对象，为视线转移和项目涉及执行眼球运动的区域。然而，LIP缺乏必要的视觉形式处理，以引导有目的的扫视行为，以特定的对象的基础上，它的功能。另一方面，V4是能够选择扫视目标的视觉区域的优秀候选者。它是一个负责物体处理的纹外皮层，具有与眼球运动相关的活动，并将直接投射发送到LIP。因此，我们建议，V4区提供的视觉输入的显着性地图表示的LIP指导眼跳模式，其特征在于自然视觉。本实验的主要目的是描述V4神经元在自由视觉搜索过程中的生理反应特性，以更好地理解它们在更自然的视觉处理中所起的作用。我们设计了一个自由观察视觉搜索任务，猴子完全自由地移动他们的眼睛，并通过非目标性的手部运动报告任务的结果。我们将检查从单个V4和LIP细胞记录的眼球运动行为和神经活动，同时猴子执行该任务以研究以下3个目的：1）我们将表征V4神经元的前扫视活动以描述它们对引导随后的扫视的贡献。2)我们将研究V4用于基于对象特征识别行为相关扫视目标的机制。3)我们将测试V4和LIP之间的连接功能。通过探索V4和LIP之间的关系，我们可以更好地理解视觉形式处理和眼动选择之间的联系，以最终在自然视觉中定位搜索目标。健康相关性：顶叶和枕叶病变患者在视觉感知和眼球运动方面存在困难。通过了解正常视觉行为的生理基础，我们可以更好地诊断和设计这些患者的康复计划。

DESCRIPTION (provided by applicant): 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 since this 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 rehabilitation programs for these patients.